spectroscopy laboratory experiment






	of the spectroscope .






	(like a filament) creates a spectrum of colors that is smooth and follows a bell curve. At around 5,000 degrees Celsius an object looks white because the spectrum centers around with lesser amounts of , , at smaller wavelengths, and lesser amounts of and at longer wavelengths.




	, but aimed at something white that is in the sunshine or even in the shade. You see a continuous shade from red to purple. It's basically the same as a rainbow.
light (which we can't see). However, this photon strikes the inside of the fluorescent bulb which is coated with various . A phosphor is a mineral that absorbs light and converts it to visible light. Zinc sulfide (ZnS) doped with silver and aluminum emits light. Many phosphors use exotic metals to create different colors.




	the type of lighting. For example, let's say we work at a company that wants to by switching all lights to the type. You can walk through the building and easily spot the that haven't been changed.

	You see the continuous spectrum of incandescent bulbs (top) and the banded spectrum of the energy saver fluorescent bulbs (bottom). So we'd know quickly that the top 4 bulbs need to be replaced.

Intro Physics for Living Systems

Lab 10: Spectroscopy

In this final lab, we will be exploring the interaction of light with matter. Using spectroscopy (also called spectral analysis , spectrometry , or spectrophotometry ), we will examine emission and absorption of light by various substances. Spectrometers (also called spectrophotometers ) are measurement tools designed to distinguish different colors of light. The spectrometers we will use in this lab detect the intensity of the light (the power-per-area associated with the light) as a function of the wavelength of the light. These spectrometers have a sensitivity range from 350 nm to 1000 nm, with a spectral resolution of 2 nm. In contrast, the human eye has a sensitivity range from approximately 400 nm (violet) to 700 nm (red), with a spectral resolution ranging from 1 nm (in the green to yellow range) to 10 nm (in the violet and red ranges). You may have been exposed to spectroscopy data through your previous chemistry and biology courses. To thoroughly understand data, one must know where it came from, its limitations, and its interpretations and potential meanings. With this lab we hope to deepen your comprehension of the function of spectrometers and thereby enrich your understanding of the data they produce. This will lay a firm foundation for your use of spectroscopy in your broader scientific career.

Matter has rich internal activity. Since matter is bound together in stable situations by forces, it has lots of natural ways to oscillate and resonate. The methyl groups on organic molecules can spin around. Similarly, long molecular chains can vibrate back-and-forth like a spring. Within each atom, electrons are constantly shifting towards and away from the nucleus. Each of these processes has a particular wavelength (color) of light associated with it: a specifically-sized photon energy packet is emitted or absorbed. Since light can only be absorbed or emitted in these packets, the way different colors of light interact with matter tells us about the energy spacing between the allowed excitation states of atoms and molecules. Doing a spectral analysis of light emitted or absorbed by something can give us a lot of information about it. Stokes (famous for his study of viscosity) was the first to show that hemoglobin was the molecule responsible for carrying oxygen in the blood—he did this using spectral analysis! On an entirely different physical scale, it’s spectral analysis that permits us to figure out the composition of stars.

Your lab will consist of three parts: I) exploring the quantized atom; II) exploring emission and absorption; and III) analyzing the emission spectrum of chlorophyll. The lab report you turn in at the end of this investigation should discuss answers to questions posed in the sections below as well as any insights you gain from your explorations and investigations, along with the data supporting those insights.

A Short Introduction to Light and Photons

All light waves move at a speed of c = 3.0 × 10 8 m/s in a vacuum. In a medium other than vacuum their speed is reduced to v = c / n , where n is the index of refraction of the medium. Since nothing can move faster than c , it follows that n ≥ 1; since n air = 1.0003, light in air moves at a speed so close to c that we don’t usually even bother distinguish between air and vacuum.
A light wave’s frequency, f , and wavelength, λ , are related with their speed, v , according to the standard wave speed equation: v = f λ .
All of these different waves are produced by electric charges moving, oscillating, and resonating in very specific ways. For each resonant frequency producing a photon of light there is an associated packet of energy, called a quantum. Because all light is made of these packets, these quanta, we say that light is quantized. The energy, E , carried by a photon is proportional to its frequency: E = hf , where the proportionality constant, h , is Planck’s constant ( h = 6.63 × 10 –34 J·s = 4.14 × 10 –15 eV·s).

The Bohr Model of the Atom

Perhaps the most famous model of the quantization is the Bohr model of the hydrogen (H) atom. In this model, the proton nucleus of the hydrogen atom is orbited by the single electron at fixed orbital radii, like a planet orbiting a star. Unlike a planet, however, the electron can have only certain discrete radii corresponding to certain discrete energies. The energy of the n th level is

E n = – E 0 /n 2

where n is the integer that labels the state. The lowest-energy state (usually called the ground state ) has n=1, corresponding to energy – E 0 ; the next-lowest-energy state (usually called the first excited state ) has n=2, corresponding to energy – E 0 /4; and so on until the highest energy state (n=∞) where E =0. Larger values of n correspond to the electron being farther and farther from the nucleus until it finally escapes altogether at n=∞ and the atom is ionized .

Δ E if = E 0 (1/n i 2 – 1/n f 2 ).

Specifically, when a H atom transitions from a higher energy state to lower energy state (that is, when n i > n f ) it must make and emit a photon containing the energy Δ E . When a H atom transitions up in energy (that is, when n i < n f ) it must obtain extra energy from somewhere; typically it gets this energy by absorbing a photon with energy Δ E . Quantitatively, conservation of energy tells us that Δ E if + E photon = 0, so

E photon = – Δ E if = E 0 (1/n f 2 – 1/n i 2 ).

In summary, only certain discrete values of energy can be emitted (or absorbed) by the atom – in accordance with the formula for Δ E above. Each of these values of Δ E corresponds to a particular wavelength (and frequency), so an atom can only emit or absorb certain discrete wavelengths of light .

Some of the energy level transitions within the hydrogen atom have been given specific names. All transitions to/from the ground state (lowest energy level, n = 1) are part of the Lyman series. All transitions to/from the 1st excited stated (n = 2) are part of the Balmer series. All transitions to/from the 2nd excited state (n = 3) are part of the Paschen series. Other transitions also have formal names, but the Lyman, Balmer, and Paschen are the most commonly encountered.

Materials and Methods

Fire up the hydrogen emission tube and clamp the end of the fiber optic up against it.
Insert the cuvette end of the fiber into the spectrometer.
Turn on the spectrometer. Its three LEDs will flash in succession.
Select “Analyze Light”
Select the “Record” button (bottom left) to start acquiring data.
Tweak the integration time and number of averages in order to obtain a large (but not cut off) signal. You may need to use different values of these parameters for different emission peaks. You should be able to locate 3 or possibly 4 emission peaks by judiciously adjusting the integration time and signal averaging.
Use “Autoscale Display” and/or click and drag on the axes to zoom the plot.
Use the “Coordinate Tool” to extract the wavelength of each peak. This tool is a box that snaps onto a peak when you drag it nearby. You may want to stop acquiring data while doing this (click the “Stop Record” button on lower left).
Calculate the photon energy E photon (in eV) corresponding to each wavelength in the emission spectrum.
Guess (or look up from a diagram of H emission spectra) n i for each wavelength. The spectrometer can only see H emission in the Balmer series (n f = 2). Calculate the quantity (1/n f 2 – 1/n i 2 ) for each photon.
Plot E photon vs (1/n f 2 – 1/n i 2 ). From the equation for E photon above, you can see that you should obtain a straight line that goes through the origin; its slope is E 0 . When you do your fit, make sure you constrain the trend line so that it goes through the origin.
Compare your value for E 0 (from the plot) to the accepted value of 13.67 eV. How well do they agree? Calculate E 0 using your data.
Hold the spectrometer’s fiber optic end up to a white LED lamp (for instance, the “flash” from your phone and to the incandescent lamp and record their spectra. You may want to use the lens to collect more light.
Record the Sun’s spectrum. Hopefully you’ll be able to do this by standing near the window, but if necessary you can plug the spectrometer into your laptop and take it outside. You will need the software, which is available on the Using our spectrometer page.
In the spectrometer’s “Analyze Light” mode, measure the spectrum of the green LED on the top of the spectrometer.
Switch to “Analyze Solution” mode and measure the absorption of a cuvette full of green food coloring.
Measure the absorption of chlorophyll.
Measure the fluorescence spectrum of chlorophyll with excitation at 405 and 500 nm.
If you are having trouble holding the optical fiber steady in front of the hydrogen tube, clamp it in place.
The spectrometer is not terribly sensitive. You can see easily in light levels that are too low for it to record via the fiber optic insert. Also, your vision adapts effortlessly to a huge range of light levels, so you are probably a very poor judge of whether a source is bright enough to be measured by the spectrometer.
You can use a lens to capture more light. Hold the fiber optic cable at the focus of the lens.
Be gentle with the fiber optic cable.
The spectrometers do have a WiFi connection, but the WiFi on the lab computers is permanently disabled. You can connect with the USB cable, though.
You may need to manually pair your spectrometer with your computer if you are using WiFi. Check the number on the bottom of the spectrometer to ensure you connect to the correct one!
In Absorbance / Transmittance mode, you will need to first take “Dark” and “Blank” measurements. See the Using our spectrometer page on our website for guidance, look at the documentation from the manufacturer (PASCO), or ask a TA for help.
All our samples are dissolved in ethanol (EthOH) so you should use plain EthOH as the blank.

Use Lab 10 blank as a template for your lab writeup.

Questions to be answered

Which series of emission lines is visible in the hydrogen emission spectrum?
Calculate E 0 (the constant in the Bohr formula for the hydrogen atom) and compare it to the accepted value of 13.6 eV.
Which artificial light source (the LED or the incandescent light) is likely to reproduce the effect of natural light more closely? Though this is a qualitative question, answer with reference to the quantitative spectra you recorded.
Compare and contrast (with measured spectra) the mechanism by which a green LED looks “green” and by which green food coloring looks “green”.
Why is the 405 nm emission spectrum so much bigger than the 500 nm curve? You will want to refer to the absorption spectrum.
You may see an extra bump in the 500 nm emission spectrum at around 500 nm (compared to the 405 nm emission spectrum). Where does this come from? Hint: it’s not real.
In our experiment, chlorophyll in solution absorbs photons and then re-emits their energy as fluorescence photons, which is kind of pointless. Inside a cell, the energy absorbed by chlorophyll as passed along to an electron acceptor (eventually making a transmembrane potential that can be used to, for instance, make ATP from ADP). Assuming that the emitted photon energy (for chlorophyll in solution) is the same as the donor electron energy (for chlorophyll in a chloroplast), estimate the % efficiency for photosynthesis using 405 nm light.

Browse Course Material

Course info.

Physics Department Faculty, Lecturers, and Technical Staff

Departments

As taught in.

Atomic, Molecular, Optical Physics

Learning Resource Types

Experimental physics i & ii "junior lab", raman spectroscopy, description.

Raman spectroscopy uses the inelastic scattering of monochromatic light to probe molecular structure. In Raman scattering, the frequency of the scattered light is shifted from the frequency of the incident beam. The rotational and vibrational energy levels of the molecule in question determine the magnitude of the frequency shift. In this experiment, you will use a high powered laser scattered off of a gaseous sample to find the rotational constants of the molecules.

Raman spectrum experiment equipment.

Greytak, T. “ Indistinguishable Particle Effects in Rotational Raman Scattering (PDF) .” MIT course 8.044 Statistical Physics I on MIT OpenCourseWare.

Zhou, H. and F. Machado, “ Raman Spectroscopy on Diatomic Molecules (PDF) .” Junior Lab Exploratory Project Proposal 2015.

Ferraro, J., K. Nakamoto, and C. Brown, Introductory Raman Spectroscopy. Amsterdam: Academic Press, 2002. ISBN: 9780122541056.

Weber, A. Raman Spectroscopy of Gases and Liquids (Topics in Current Physics). Berlin: Springer-Verlag, 1979.

Edwards, D. F. and C. Y. She, “ Laser Excited Raman Spectroscopy .” American Journal of Physics 40 (1972): 1389-1399.

You are leaving MIT OpenCourseWare

An official website of the United States government

Here's how you know

Official websites use .gov A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Facebook
Twitter
Linkedin
Digg
Reddit
Pinterest
Email

Latest Earthquakes | Chat Share Social Media

Spectroscopy Lab

Researchers at the USGS Spectroscopy Lab are studying and applying methods for identifying and mapping materials through spectroscopic remote sensing (called imaging spectroscopy, hyperspectral imaging,imaging spectrometry, ultraspectral imaging, etc), on the earth and throughout the solar system using laboratory, field, airborne and spacecraft spectrometers.

USGS Digital Spectral Libraries

Collage of spectral library data and spectroscopy laboratory images

Reflectance spectra of minerals, mineral mixtures, rock coatings, liquids, frozen volatiles, organic compounds, manmade materials, vegetation, and other biological materials. You can download the main spectral library

Hyperspectral Imaging Spectrometer Maps

Maps of hyperspectral imaging spectrometer data used to identify and characterize mineral deposits, vegetation, and other land surface features.

Secretary of the Interior Visits Geology, Geophysics, and Geochemistry Science Center

Spectroscopy lab hosts hyperspectral imaging-uas training, u.s. geological survey and colorado school of mines announce long-term partnership, publications, hyperspectral (vnir-swir) analysis of roll front uranium host rocks and industrial minerals from karnes and live oak counties, texas coastal plain.

VNIR-SWIR (400–2500 nm) reflectance measurements were made on the surfaces of various cores, cuttings and sample splits of sedimentary rocks from the Tertiary Jackson Group, and Catahoula, Oakville and Goliad Formations. These rocks vary in composition and texture from mudstone and claystone to sandstone and are known host rocks for roll front uranium occurrences in Karnes and Live Oak Counties, T

The EnMAP imaging spectroscopy mission towards operations

Hyperspectral remote sensing of white mica: a review of imaging and point-based spectrometer studies for mineral resources, with spectrometer design considerations.

Collage of airborne spectroscopy imagery

Spectroscopy and Hyperspectral Imaging of Critical Mineral Resources

scientist walking in desert with equipment

Hyperspectral Imaging of Mineral Resources from New and Old Origins: Minerals for the Nation’s Economy and Utilization of Legacy Mine Lands

Scanning Electron Image of Vermiculite Asbestos

Using In Situ IR Spectroscopy Measurements of Vermiculite Insulation to Determine Its Origin

November 10, 2015

Mildred Dresselhaus, MIT

on March 19.

-->

Join us for the on October 13, 2015.

Adam Wax

Duke University

Nanoscale Imaging and Sensing of Live Cells.

On October 20, 2015

Michael Morse

University of Utah

Transition Metal Spectroscopy: From Diatomic Metals to the Metal-Carbon Bond

-->
The Spectroscopy Laboratory mourns the death of Dr. Michael Feld, late director of the Spectroscopy Laboratory and MIT Professor of Physics.

Celebrating 2010 as the 50th anniversary of the laser. Join events throughout the year and around the world that showcase how the laser works, the history of the laser and its impact on society, and the laser's potential for the future.

-->

LBRC LASER B IOMEDICAL RESEARCH CENTER

[ | | | | | | | | ]

Spectroscopy

Astronomical images carry a lot of scientific information hidden within the beautiful colors, but even that’s only part of the story. A great deal of knowledge comes from analyzing the light as broken down into its spectrum. The specific colors and relative amounts of each color reveal information about temperature, what atoms are present, and the speed of the astronomical object being observed, which reveals the distances to far-off galaxies. For those reasons, spectroscopy is one of the essential tools of astronomy.

Center for Astrophysics | Harvard & Smithsonian scientists apply spectroscopy to every aspect of astronomy:

Hunting for absorption spectra in the atmospheres of exoplanets, using the next generation of telescopes. Future observatories such as the Giant Magellan Telescope (GMT) will be able to detect the spectrum from traces of oxygen and water, chemicals that are important for life as we know it. Potentially Habitable Super-Earth is a Prime Target for Atmospheric Study

Developing new spectrographs for the next-generation observatories, including the GMT. The GMT-Consortium Large Earth Finder (G-CLEF) is a precision spectrograph designed to measure Doppler effect red- and blueshifts for exoplanets, down to 10 centimeters per second, or less than a quarter of a mile per hour — about the rate an ant walks. CfA Research: http://gclef.cfa.harvard.edu/

Studying the spectrum of interesting environments, including the regions around newborn star systems. Astronomers use the Atacama Large Millimeter/submillimeter Array (ALMA) and other observatories to identify molecules from their spectrum. In that away, they identified an organic molecule in common between an infant star system and a comet in the Solar System. Astronomers Discover Traces of Methyl Chloride around Infant Stars and Nearby Comet

computer-generated preview of the Giant Magellan Telescope

The Giant Magellan Telescope (GMT) will carry the G-CLEF spectrometer to study the atmospheres of exoplanets and perform other spectroscopic measurements. This computer-generated image shows the GMT at sunset, preparing for observations.

The Quantum Rainbow

As Isaac Newton demonstrated in 1704, white light is a mixture of all the colors of the rainbow, which can be separated using a prism or — in the case of a real rainbow — a drop of water. In the 19th century, scientists realized they could identify different types of atom by the light they emitted. A group of astronomers even discovered the element helium by looking at the spectrum from the Sun, naming it for “Helios”, the Greek sun god.

Spectroscopy rapidly became a powerful tool in both chemistry and astronomy. The quantum theory of atoms provided an explanation for the unique spectrum of each element and molecule. Thanks to the particular interactions between the electrons and nuclei, each type of atom or molecule can only absorb or emit light of specific wavelengths, which are the physical property of light that gives its color. For instance, colors of neon, krypton, or sodium light bulbs are colored red, blue, and yellow because atoms of those elements emit most of their light in those wavelengths.

Today, astronomers use that quantum knowledge to build spectrographs, which split light into its component colors in a more precise way than Newton’s glass prism. By seeing which colors are emitted or absorbed, and the relative amounts of each wavelength, astronomers can identify the chemical composition of a star’s atmosphere or an interstellar nebula , along with the temperature and pressure of the gas.

Astronomers also use known spectra to measure the distance to galaxies. The universe is expanding, carrying galaxies along with it, so distant galaxies appear to be moving away from us. The light emitted by those galaxies is “redshifted”, meaning it’s stretched to longer wavelengths. The larger the redshift, the faster the galaxy seems to be moving, and the farther away it is. By identifying how much the spectrum of hydrogen from distant galaxies is redshifted, astronomers can measure the distance to those galaxies.

On a smaller scale, astronomers use spectroscopy to measure the the motion of a star in a binary star system, from an orbiting exoplanet, due to the tug of a black hole, or any number of other possibilities. The motion of the star toward us blueshifts the light slightly, moving it to shorter wavelengths, while moving away redshifts the light. This is the Doppler effect for light, the same essential phenomena produced when an ambulance siren changes pitch as it passes.

Laboratory Spectroscopy

Researchers also do spectroscopy in the lab, studying the spectrum of different elements and molecules under a variety of conditions.

For example, experiments have determined that the relative strength of two emission lines in a spectrum provides an independent test of the temperature and density of the atoms making that spectrum. That in turn is useful for astronomical observations.

Astrochemists have also produced and studied complex organic molecules in the lab under simulated interstellar conditions. These molecules were later observed in space, confirming the experiments’ findings.

Laboratory research in astrochemistry studies how ionization changes the spectrum of atoms and molecules. Ionization in astronomy means stripping electrons away, turning the material into a plasma. This happens in many astronomical environments, including the atmospheres of stars, interstellar space, the region between galaxies in a galaxy cluster , and many other places. Using laboratory experiments and theoretical calculations, researchers develop methods of studying astronomical plasmas and the processes that made them.

What is the universe made of?
How do stars and planets form and evolve?
Solar & Heliospheric Physics
Instrumentation
Laboratory Astrophysics
Stellar Astronomy
Planetary Systems
Atomic and Molecular Physics
Radio and Geoastronomy

Related News

Nasa media call on upcoming air quality satellite launch, media advisory: new space instrument to deliver near real-time air pollution data, air pollution sensor integrated and tested with commercial satellite host, first rocky exoplanet confirmed with nasa's jwst, a leading light in atmospheric science, new from jwst: an exoplanet atmosphere as never seen before, astronomers warn of risk of misinterpreting jwst planetary signals, new grant supports teen air quality studies, astronomers detect carbon dioxide on planet for the first time with jwst, tempo air pollution instrument completes satellite integration, hitran and hitemp database, sensing the dynamic universe, pintofale (package for interactive analysis of line emission), telescopes and instruments, air-spec/aspire, solar and heliospheric observer (soho), solar dynamics observatory (sdo), the coronal spectrographic imager in the euv (cosie).

Sensitive and reliable lab-on-paper biosensor for label-free detection of exosomes by electrochemical impedance spectroscopy

Published: 24 September 2024
Volume 191 , article number 617 , ( 2024 )

Cite this article

Sevda Akay Sazaklioglu 1 , 2 ,
Hilal Torul 3 ,
Uğur Tamer 3 , 4 ,
Hilal Kabadayi Ensarioglu 5 ,
Hafize Seda Vatansever 5 , 6 ,
Bilal H. Gumus 7 &
Hüseyin Çelikkan 8

51 Accesses

Explore all metrics

A new, sensitive, and cost-effective lab-on-paper-based immunosensor was designed based on electrochemical impedance spectroscopy (EIS) for the detection of exosomes. EIS was selected as the determination method since there was a surface blockage in electron transfer by binding the exosomes to the transducer. Briefly, the carbon working electrode (WE) on the paper electrode (PE) was modified with gold particles (AuPs@PE) and then conjugated with anti-CD9 (Anti-CD9/AuPs@PE) for the detection of exosomes. Variables involved in the biosensor design were optimized with the univariate mode. The developed method presents the limit of detection of 8.7 × 10 2 exosomes mL −1 , which is lower than that of many other available methods under the best conditions. The biosensor was also tested with urine samples from cancer patients with high recoveries. Due to this a unique, low-cost, biodegradable technology is presented that can directly measure exosomes without labeling them for early cancer or metastasis detection.

Graphical abstract

This is a preview of subscription content, log in via an institution to check access.

Access this article

Subscribe and save.

Get 10 units per month
Download Article/Chapter or eBook
1 Unit = 1 Article or 1 Chapter
Cancel anytime

Price includes VAT (Russian Federation)

Instant access to the full article PDF.

Rent this article via DeepDyve

Institutional subscriptions

Direct impedimetric detection of exosomes and practical application in urine

Chitosan–Fe 3 O 4 nanoparticle enzymatic electrodes on paper as an efficient assay for glucose and uric acid detection in biological fluids

Data availability.

No datasets were generated or analysed during the current study.

Fitzmaurice C, Dicker D, Pain A et al (2015) The Global Burden of Cancer 2013. JAMA Oncol 1:505–527. https://doi.org/10.1001/jamaoncol.2015.0735

Article PubMed Google Scholar

Sidorova EA, Zhernov Y, v., Antsupova MA, et al (2023) The role of different types of microRNA in the pathogenesis of breast and prostate cancer. Int J Mol Sci 24:1980. https://doi.org/10.3390/ijms24031980

Article CAS PubMed PubMed Central Google Scholar

Aprile M, Costa V, Cimmino A, Calin GA (2022) Emerging role of oncogenic long noncoding RNA as cancer biomarkers. Int J Cancer 152:822–834

Becker A, Thakur BK, Weiss JM et al (2016) Extracellular vesicles in cancer: cell-to-cell mediators of metastasis. Cancer Cell 30:836–848

Keller S, König AK, Marmé F et al (2009) Systemic presence and tumor-growth promoting effect of ovarian carcinoma released exosomes. Cancer Lett 278:73–81. https://doi.org/10.1016/j.canlet.2008.12.028

Article CAS PubMed Google Scholar

Le MTN, Hamar P, Guo C et al (2014) MiR-200-containing extracellular vesicles promote breast cancer cell metastasis. J Clin Investig 124:5109–5128. https://doi.org/10.1172/JCI75695

Article PubMed PubMed Central Google Scholar

Melo SA, Luecke LB, Kahlert C et al (2015) Glypican-1 identifies cancer exosomes and detects early pancreatic cancer. Nature 523:177–182. https://doi.org/10.1038/nature14581

Liu X, Lu Y, Xu Y et al (2019) Exosomal transfer of miR-501 confers doxorubicin resistance and tumorigenesis via targeting of BLID in gastric cancer. Cancer Lett 459:122–134. https://doi.org/10.1016/j.canlet.2019.05.035

Khan S, Bennit HF, Turay D, et al (2014) Early diagnostic value of surviving and its alternative splice variants in breast cancer. BMC Cancer 14:. https://doi.org/10.1186/1471-2407-14-176

Taylor DD, Gercel-Taylor C (2008) MicroRNA signatures of tumor-derived exosomes as diagnostic biomarkers of ovarian cancer. Gynecol Oncol 110:13–21. https://doi.org/10.1016/j.ygyno.2008.04.033

Riches A, Campbell E, Borger E, Powis S (2014) Regulation of exosome release from mammary epithelial and breast cancer cells-a new regulatory pathway. Eur J Cancer 50:1025–1034. https://doi.org/10.1016/j.ejca.2013.12.019

Kim B, Kim K-M (2023) Role of exosomes and their potential as biomarkers in Epstein-Barr virus-associated gastric cancer. Cancers (Basel) 15:469. https://doi.org/10.3390/cancers15020469

Bamankar S, Londhe VY (2023) The rise of extracellular vesicles as new age biomarkers in cancer diagnosis: promises and pitfalls. Technol Cancer Res Treat 22 https://doi.org/10.1177/15330338221149266

Zhou Y, Chi H, Wu Y et al (2016) Organic additives stabilize RNA aptamer binding of malachite green. Talanta 160:172–182. https://doi.org/10.1016/j.talanta.2016.06.067

Chen J, Meng HM, An Y, et al (2020) Structure-switching aptamer triggering hybridization displacement reaction for label-free detection of exosomes. Talanta 209:. https://doi.org/10.1016/j.talanta.2019.120510

Zheng XS, Jahn IJ, Weber K et al (2018) Label-free SERS in biological and biomedical applications: recent progress, current challenges and opportunities. Spectrochim Acta A Mol Biomol Spectrosc 197:56–77. https://doi.org/10.1016/j.saa.2018.01.063

Wang Q, Zou L, Yang X et al (2019) Direct quantification of cancerous exosomes via surface plasmon resonance with dual gold nanoparticle-assisted signal amplification. Biosens Bioelectron 135:129–136. https://doi.org/10.1016/j.bios.2019.04.013

Zhang J, Wang LL, Hou MF et al (2018) A ratiometric electrochemical biosensor for the exosomal microRNAs detection based on bipedal DNA walkers propelled by locked nucleic acid modified toehold mediate strand displacement reaction. Biosens Bioelectron 102:33–40. https://doi.org/10.1016/j.bios.2017.10.050

Taylor DD, Gercel-Taylor C (2011) Exosomes/microvesicles: mediators of cancer-associated immunosuppressive microenvironments. Semin Immunopathol 33:441–454

Seipold L, Saftig P (2016) The emerging role of tetraspanins in the proteolytic processing of the amyloid precursor protein. Front Mol Neurosci 9:. https://doi.org/10.3389/fnmol.2016.00149

Brosseau C, Colas L, Magnan A, Brouard S (2018) CD9 tetraspanin: a new pathway for the regulation of inflammation? Front Immunol 9:2316

Khushman M, Bhardwaj A, Patel GK, et al (2017) Exosomal markers (CD63 and CD9) expression pattern using immunohistochemistry in resected malignant and nonmalignant pancreatic specimens. In: Pancreas. Lippincott Williams and Wilkins, pp 782–788

Grønborg M, Kristiansen TZ, Iwahori A et al (2006) Biomarker discovery from pancreatic cancer secretome using a differential proteomic approach. Mol Cell Proteomics 5:157–171

An J, Park H, Kim J et al (2023) Extended-gate field-effect transistor consisted of a CD9 aptamer and MXene for exosome detection in human serum. ACS Sens 8:3174–3186. https://doi.org/10.1021/acssensors.3c00879

Doldán X, Fagúndez P, Cayota A et al (2016) Electrochemical sandwich immunosensor for determination of exosomes based on surface marker-mediated signal amplification. Anal Chem 88:10466–10473. https://doi.org/10.1021/acs.analchem.6b02421

Sazaklıoğlu SA, Torul H, Vatansever HS et al (2022) Direct impedimetric detection of exosomes and practical application in urine. J Appl Electrochem. https://doi.org/10.1007/s10800-022-01753-3

Dutta G (2022) Electrochemical detection of cancer fingerprint: a systematic review on recent progress in extracellular vesicle research from lab to market. In: Next-Generation Nanobiosensor Devices for Point-Of-Care Diagnostics. Springer Nature. https://doi.org/10.1007/978-981-19-7130-3_3

Pandey N, Mandal M, Samanta D, et al (2023) A nanobody based ultrasensitive electrochemical biosensor for the detection of soluble CTLA-4 –A candidate biomarker for cancer development and progression. Biosens Bioelectron 242:. https://doi.org/10.1016/j.bios.2023.115733

Lazanas AC, Prodromidis MI (2023) Electrochemical impedance spectroscopy─a tutorial. ACS Measurement Science Au 3:162–193

Pradhan R, Kalkal A, Jindal S et al (2020) Four electrode-based impedimetric biosensors for evaluating cytotoxicity of tamoxifen on cervical cancer cells. RSC Adv 11:798–806. https://doi.org/10.1039/d0ra09155c

Uygun ZO, Yeniay L, Gi̇rgi̇nSağın F, (2020) CRISPR-dCas9 powered impedimetric biosensor for label-free detection of circulating tumor DNAs. Anal Chim Acta 1121:35–41. https://doi.org/10.1016/j.aca.2020.04.009

Xie Q-Z, Lin M-W, Hsu W-E, Lin C-T (2020) Review—advancements of nanoscale structures and materials in impedimetric biosensing technologies. ECS J Solid State Sci Technol 9:115027. https://doi.org/10.1149/2162-8777/abbcb3

Article CAS Google Scholar

Kirchhain A, Bonini A, Vivaldi F et al (2020) Latest developments in non-faradic impedimetric biosensors: towards clinical applications. TrAC - Trends in Anal Chem 133:116073

Dutta G, Rainbow J, Zupancic U et al (2018) Microfluidic devices for label-free DNA detection. Chemosensors 6:43

Diaz-Armas GG, Cervantes-Gonzalez AP, Martinez-Duarte R, Perez-Gonzalez VH (2022) Electrically driven microfluidic platforms for exosome manipulation and characterization. Electrophoresis 43:327–339

Prodromidis MI (2010) Impedimetric immunosensors-a review. Electrochim Acta 55:4227–4233

Dutta G, Jallow AA, Paul D, Moschou D (2019) Label-free electrochemical detection of S. mutans exploiting commercially fabricated printed circuit board sensing electrodes. Micromachines (Basel) 10:. https://doi.org/10.3390/mi10090575

Ming T, Luo J, Liu J et al (2020) Paper-based microfluidic aptasensors. Biosens Bioelectron 170:112649

Yarali E, Eksin E, Torul H, et al (2022) Impedimetric detection of miRNA biomarkers using paper-based electrodes modified with bulk crystals or nanosheets of molybdenum disulfide. Talanta 241:. https://doi.org/10.1016/j.talanta.2022.123233

Ozer T, Henry CS (2021) Paper-based analytical devices for virus detection: recent strategies for current and future pandemics. TrAC-Trends Anal Chem 144:116424

Liu S, Su W, Ding X (2016) A review on microfluidic paper-based analytical devices for glucose detection. Sensors (Switzerland) 16:1–17

Article Google Scholar

Pang R, Zhu Q, Wei J et al (2022) Enhancement of the detection performance of paper-based analytical devices by nanomaterials. Molecules 27:508

Wang P, Kricka LJ (2018) Current and emerging trends in point-of-care technology and strategies for clinical validation and implementation. Clin Chem 64:1439–1452

Biswas P, Mukherjee A, Goyal P, et al (2024) A rapid diagnostic technology for isolating rare blood group patients under medical emergency using a three-fold paper-polymer microfluidic kit. Sens Actuators B Chem 409:. https://doi.org/10.1016/j.snb.2024.135650

St John A, Price CP point-of-care testing technologies Clin Biochem Rev 35 (3) 2014 155 Existing and Emerging Technologies for Point-of-Care Testing

PubMed PubMed Central Google Scholar

Yetisen AK, Akram MS, Lowe CR (2013) Paper-based microfluidic point-of-care diagnostic devices. Lab Chip 13:2210–2251

Sazaklioglu SA, Torul H, Kabadayi H et al (2022) Calibration curve approaches for nonlinear data points obtained in Colo 320 exosomes determination. Anal Bioanal Electrochem 14(11):1027–43

CAS Google Scholar

Wongkaew N, Simsek M, Griesche C, Baeumner AJ (2019) Functional nanomaterials and nanostructures enhancing electrochemical biosensors and lab-on-a-chip performances: recent progress, applications, and future perspective. Chem Rev 119:120–194

Collinson MM (2013) Nanoporous gold electrodes and their applications in analytical chemistry. ISRN Anal Chem 2013:1–21. https://doi.org/10.1155/2013/692484

Eksin E, Torul H, Yarali E, et al (2021) Paper-based electrode assemble for impedimetric detection of miRNA. Talanta 225:. https://doi.org/10.1016/j.talanta.2020.122043

Yu Y, Li YT, Jin D et al (2019) Electrical and label-free quantification of exosomes with a reduced graphene oxide field effect transistor biosensor. Anal Chem 91:10679–10686. https://doi.org/10.1021/acs.analchem.9b01950

Pan S, Pei L, Zhang A, et al (2020) Passion fruit-like exosome-PMA/Au-BSA@Ce6 nanovehicles for real-time fluorescence imaging and enhanced targeted photodynamic therapy with deep penetration and superior retention behavior in tumor. Biomaterials 230 https://doi.org/10.1016/j.biomaterials.2019.119606

Rafighdoust Z, Baharara J, Forghanifard MM, Kerachian MA (2021) Isolation and characterization of exosomes derived from breast cancer MDA-MB-231 cell line. Gene Cell Tissue 8 https://doi.org/10.5812/gct.110505

Kore RA, Henson JC, Hamzah RN, et al (2019) Molecular events in MSC exosome mediated cytoprotection in cardiomyocytes. Sci Rep 9 https://doi.org/10.1038/s41598-019-55694-7

Kilic T, Valinhas ATDS, Wall I, et al (2018) Label-free detection of hypoxia-induced extracellular vesicle secretion from MCF-7 cells. Sci Rep 8 https://doi.org/10.1038/s41598-018-27203-9

Liu W, Li J, Wu Y et al (2018) Target-induced proximity ligation triggers recombinase polymerase amplification and transcription-mediated amplification to detect tumor-derived exosomes in nasopharyngeal carcinoma with high sensitivity. Biosens Bioelectron 102:204–210. https://doi.org/10.1016/j.bios.2017.11.033

Gu C, Bai L, Pu L, et al (2021) Highly sensitive and stable self-powered biosensing for exosomes based on dual metal-organic frameworks nanocarriers. Biosens Bioelectron 176 https://doi.org/10.1016/j.bios.2020.112907

da Li T, Zhang R, Chen H et al (2018) An ultrasensitive polydopamine bi-functionalized SERS immunoassay for exosome-based diagnosis and classification of pancreatic cancer. Chem Sci 9:5372–5382. https://doi.org/10.1039/c8sc01611a

Xu H, Liao C, Zuo P et al (2018) Magnetic-based microfluidic device for on-chip isolation and detection of tumor-derived exosomes. Anal Chem 90:13451–13458. https://doi.org/10.1021/acs.analchem.8b03272

Liu L, Thakur A, Kar Li W, et al (2022) Site specific biotinylated antibody functionalized Ag@AuNIs LSPR biosensor for the ultrasensitive detection of exosomal MCT4, a glioblastoma progression biomarker. Chem Eng J 446 https://doi.org/10.1016/j.cej.2022.137383

Wang S, Zhang L, Wan S et al (2017) Aptasensor with expanded nucleotide using DNA nanotetrahedra for electrochemical detection of cancerous exosomes. ACS Nano 11:3943–3949. https://doi.org/10.1021/acsnano.7b00373

Li Q, Tofaris GK, Davis JJ (2017) Concentration-normalized electroanalytical assaying of exosomal markers. Anal Chem 89:3184–3190. https://doi.org/10.1021/acs.analchem.6b05037

Chen J, Xu Y, Lu Y, Xing W (2018) Isolation and visible detection of tumor-derived exosomes from plasma. Anal Chem 90:14207–14215. https://doi.org/10.1021/acs.analchem.8b03031

Joshi S, Raj KA, Rao MR, Ghosh R (2022) An electronic biosensor based on semiconducting tetrazine polymer immobilizing matrix coated on rGO for carcinoembryonic antigen. Sci Rep 12 https://doi.org/10.1038/s41598-022-06976-0

Suan Ng S, Ling Lee H, Bothi Raja P, Doong R an (2022) Recent advances in nanomaterial-based optical biosensors as potential point-of-care testing (PoCT) probes in carcinoembryonic antigen detection. Chem Asian J https://doi.org/10.1002/asia.202200287

Li J, Liu L, Ai Y et al (2020) Self-polymerized dopamine-decorated Au NPs and coordinated with Fe-MOF as a dual binding sites and dual signal-amplifying electrochemical aptasensor for the detection of CEA. ACS Appl Mater Interfaces 12:5500–5510. https://doi.org/10.1021/acsami.9b19161

Moreno García V, Cejas P, Blanco Codesido M et al (2009) Prognostic value of carcinoembryonic antigen level in rectal cancer treated with neoadjuvant chemoradiotherapy. Int J Colorectal Dis 24:741–748. https://doi.org/10.1007/s00384-009-0682-6

Snider J, Kotlyar M, Saraon P, et al (2015) Fundamentals of protein interaction network mapping. Mol Syst Biol 11:848 https://doi.org/10.15252/msb.20156351

Soltermann F, Struwe WB, Kukura P (2021) Label-free methods for optical: In vitro characterization of protein-protein interactions. Phys Chem Chem Phys 23:16488–16500. https://doi.org/10.1039/d1cp01072g

Roth S, Zander I, Michelson Y, et al (2020) Identification of protein-protein interactions using a magnetic modulation biosensing system. Sens Actuators B Chem 303:. https://doi.org/10.1016/j.snb.2019.127228

Lorencova L, Bertok T, Bertokova A et al (2020) Exosomes as a source of cancer biomarkers: advances in electrochemical biosensing of exosomes. ChemElectroChem 7:1956–1973

Tutanov O, Proskura K, Kamyshinsky R, et al (2020) Proteomic profiling of plasma and total blood exosomes in breast cancer: a potential role in tumor progression, diagnosis, and prognosis. Front Oncol 10:. https://doi.org/10.3389/fonc.2020.580891

Download references

Acknowledgements

The authors are thankful to Gazi University Scientific Research Office (FCD-2021-7119). This study originated from a section of Sevda Akay Sazaklioglu’s Ph.D. thesis.

Author information

Authors and affiliations.

Faculty of Pharmacy, Department of Analytical Chemistry, Ankara Medipol University, 06050, Ankara, Turkey

Sevda Akay Sazaklioglu

Graduate School of Natural and Applied Science, Gazi University, 06560, Ankara, Turkey

Faculty of Pharmacy, Department of Analytical Chemistry, Gazi University, 06330, Ankara, Turkey

Hilal Torul & Uğur Tamer

METU MEMS Center, Ankara, Turkey

Faculty of Medicine, Department of Histology and Embryology, Manisa Celal Bayar University, 45200, Manisa, Turkey

Hilal Kabadayi Ensarioglu & Hafize Seda Vatansever

DESAM Institute, Near East University, Mersin 10, Turkey

Hafize Seda Vatansever

Faculty of Medicine, Department of Urology, Manisa Celal Bayar University, 45200, Manisa, Turkey

Bilal H. Gumus

Faculty of Science, Department of Chemistry, Gazi University, 06560, Ankara, Turkey

Hüseyin Çelikkan

You can also search for this author in PubMed Google Scholar

Contributions

Sevda Akay Sazaklioglu data curation, investigation, methodology, writing of the original draft, and validation. Hilal Torul investigation, methodology, and formal analysis. Uğur Tamer conceptualization, methodology, and supervision. Hilal Kabadayi Ensarioglu data curation and investigation. Hafize Seda Vatansever resources and methodology. Bilal H. Gumus resources and methodology. Hüseyin Çelikkan conceptualization, methodology, supervision, funding acquisition, review & editing of the manuscript.

Corresponding author

Correspondence to Hüseyin Çelikkan .

Ethics declarations

Ethics approval.

The urine samples used in this Project were collected with the collaboration work of Manisa Celal Bayar University Faculty of Medicine Department of Urology and Manisa Celal Bayar University Faculty of Medicine, Department of Histology and Embryology with the approval of Manisa Celal Bayar University Faculty of Medicine Health Sciences Ethics Committee dated 25/10/2017 and numbered 20.478.486–164.

Conflict of interest

The authors declare no competing interests.

Additional information

Publisher's note.

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

• Impedimetric detection of exosomes with paper electrodes has been suggested for early cancer detection.

• Simple, rapid, real-time quantitative determination of exosomes takes only 40 min.

• The lowest LOD for exosomes in PBS medium was 8.7 × 10 2 exosomes mL −1 .

• The biosensor design allowed analysis in a sample volume as low as 5 µL.

• Exosomes in urine samples taken from patients were detected with 79% to 110% recoveries.

Supplementary Information

Below is the link to the electronic supplementary material.

Supplementary file1 (DOCX 2180 KB)

Rights and permissions.

Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.

Reprints and permissions

About this article

Sazaklioglu, S.A., Torul, H., Tamer, U. et al. Sensitive and reliable lab-on-paper biosensor for label-free detection of exosomes by electrochemical impedance spectroscopy. Microchim Acta 191 , 617 (2024). https://doi.org/10.1007/s00604-024-06644-2

Download citation

Received : 10 July 2024

Accepted : 19 August 2024

Published : 24 September 2024

DOI : https://doi.org/10.1007/s00604-024-06644-2

Share this article

Anyone you share the following link with will be able to read this content:

Sorry, a shareable link is not currently available for this article.

Provided by the Springer Nature SharedIt content-sharing initiative

Paper-based electrode
Gold particle modified electrode
Electrochemical impedance spectroscopy
Label-free detection
Find a journal
Publish with us
Track your research

Current Article

PPRI seeks faculty-student bids for unique State Department policy-development program

WEST LAFAYETTE, Ind. — The Purdue Policy Research Institute (PPRI) is inviting proposals for participation in the spring 2025 Diplomacy Lab , a U.S. Department of State initiative that connects with academic institutions to address real-world policy challenges.

Through the PPRI Diplomacy Lab initiative , students can gain valuable learning opportunities while giving the State Department fresh perspectives on complex problems. The program covers a wide range of topics such as climate change, sustainable development, human rights, economic policy, global health, energy security, conflict and stabilization, and more.

The Diplomacy Lab seeks teams of Purdue students, each led and supervised by a faculty member, to conduct research in those and other areas of interest relevant to the State Department’s affairs.

Those wishing to apply can use the menu of projects available in creating their project bid. PPRI is coordinating the application process, which is currently open to faculty at all Purdue campuses. Project bids, which are limited to 200 words, are to be submitted in a Word document or directly via email to [email protected] , before noon ET, Oct. 3.

Each bid must state the project of interest and explain how the project will be conducted (as a course, capstone, stand-alone project, etc.). It also must explain the planned approach(es) and note whether the student team will be composed of undergraduates, graduate students or both. Purdue will submit up to six project bids.

The State Department will review submissions from the first round of bidding and respond with decisions after Oct. 18. A second round of bidding will be announced in late October.

General queries regarding the Diplomacy Lab initiative or the bidding process should be emailed to Krista Kelley, PPRI senior operations manager, [email protected] . To learn more about Purdue’s partnership with the Diplomacy Lab program, please watch this PPRI-led info session . For more information, please visit PPRI’s Diplomacy Lab web page .

About Diplomacy Lab

Launched by the Department of State in 2013, Diplomacy Lab enables the State Department to “course-source” research related to foreign policy challenges by harnessing the efforts of students and faculty experts at colleges and universities across the United States. Diplomacy Lab underscores the State Department’s commitment to engage the American people in its work, and the need to broaden its research base in response to the proliferation of complex global challenges.

About the Purdue Policy Research Institute

The Purdue Policy Research Institute (PPRI) catalyzes and leverages extant policy-relevant transdisciplinary research among members of the Purdue research community, facilitates enduring connections among local and global actors, and generates impact on policymaking and beyond. The institute is guided by the principle that policy development must consider the interdependencies among technological, economic, ethical, and social factors. Together with collaborators in academia and the public and private sectors, PPRI inspires the development of nonpartisan policies that solve pressing global challenges.

Source: [email protected]

An official website of the United States government

Here's how you know

Official websites use .gov A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS A lock ( Lock Locked padlock ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

The Attorney General
Organizational Chart
Budget & Performance
Privacy Program
Press Releases
Photo Galleries
Guidance Documents
Publications
Information for Victims in Large Cases
Justice Manual
Business and Contracts
Why Justice ?
DOJ Vacancies
Legal Careers at DOJ

Hospital, Laboratory, Referring Physician, and Lab Employees Pay More than $7.2 Million To Resolve Civil Allegations of Fraudulent Laboratory Testing

LEXINGTON, Ky. — A hospital, a laboratory, three lab employees, and a referring physician and his office manager have agreed to collectively pay the United States more than $7.2 million dollars to resolve civil allegations that they defrauded federal healthcare programs in connection with laboratory tests that were not medically necessary or were tainted by violations of the federal Anti-Kickback Statute.

Physicians’ Medical Center, LLC (“PMC”), a hospital in New Albany, Indiana, operated a clinical laboratory that was managed by the now defunct United States Medical Scientific Indiana, LLC (“US Med Sci Indiana”). The United States alleged that PMC, through its lab manager’s fraudulent conduct, violated the False Claims Act by submitting false claims for laboratory services to Medicare, Kentucky Medicaid, and TRICARE, from December 2016 to September 2018.

Federal healthcare programs only pay for laboratory services that are used for medical diagnosis or treatment. As set forth in the settlement documents, the United States alleged that PMC billed Medicare, Kentucky Medicaid, and TRICARE for urine drug tests referred by various entities – including a homeless shelter and peer-to-peer recovery centers – that did not use the test results for medical diagnosis or treatment. These nonmedical entities only used the test results to monitor clients’ compliance with the conditions of their programs and with court orders. In total, the United States alleged that PMC submitted nearly $3 million in false claims to Medicare, Kentucky Medicaid, and TRICARE, for urine drug tests referred by these nonmedical entities.

Two lab employees also entered settlement agreements to resolve their False Claims Act liability, for causing PMC’s submission of false claims for lab tests from these nonmedical entities. The United States alleged that Bobby Sturgeon, a sales representative for PMC’s laboratory, knew that these entities did not provide medical services, but nonetheless pursued and worked with them as clients. And Sturgeon financially benefited from these fraudulent sales practices because his salary was based in part on the amount insurers paid PMC for his clients’ tests, including those from the nonmedical entities. Similarly, the United States alleged that Derrick Arthur, one of the peer-to-peer recovery center’s directors, worked as a specimen collector for PMC’s lab and helped arrange for a volunteer doctor to order urine drug testing, despite knowing that the doctor did not provide medical treatment to the center’s clients. By doing so, Arthur facilitated the improper billing of laboratory tests to federal healthcare programs.

After PMC closed its laboratory in October 2018, Sturgeon became a sales representative for Bluewater Toxicology, a laboratory in Mount Washington, Kentucky. As set forth in the settlement documents, Sturgeon then caused Bluewater to submit false claims for medically unnecessary urine drug tests, from the same peer-to-peer recovery centers and homeless shelter, through July 2019. Like PMC, Bluewater knew that federal healthcare programs would not pay for urine drug tests used for nonmedical purposes, but still submitted the claims for payment. In total, the United States alleged that Bluewater submitted nearly $450,000 in false claims to Medicare and Kentucky Medicaid for urine drug tests referred by the nonmedical entities. Bluewater, Sturgeon, and Arthur have entered settlement agreements resolving their liability for the submission of Bluewater’s false claims for tests from these nonmedical entities.

In a related scheme, Steve Moore, a laboratory sales representative for PMC and Bluewater Toxicology, allegedly paid a physician, Pablo Merced, M.D., and his wife and office manager, Theresa Merced, to induce referrals of laboratory tests to PMC and Bluewater Toxicology. To gain Dr. Merced’s large volume of referrals, Moore paid cash to the Merceds and paid additional salary to lab specimen collectors who worked at their office. PMC, through its lab manager, also employed specimen collectors in Dr. Merced’s medical practice, who were alleged to perform office work unrelated to their specimen collection duties. Moore’s cash payments and the PMC lab manager’s in-kind payments to the Merceds violated the Anti-Kickback Statute, 42 U.S.C. § 1320a-7b(b). PMC and Bluewater submitted millions of dollars of claims to federal healthcare programs for the lab tests that were tainted by their sales representative’s kickbacks. PMC, Moore, and the Merceds have entered settlement agreements resolving their liability for the submission of the false claims tainted by kickbacks.

PMC’s settlement agreement also resolved its False Claims Act liability for claims for lab tests referred by medical providers at Prescribe Recovery, a medical practice in Paris, Kentucky. The United States alleged that PMC’s lab manager, US Med Sci Indiana, actually owned Prescribe Recovery, and directed its medical providers’ referral of laboratory tests to PMC’s lab. As PMC’s lab manager, US Med Sci Indiana received 78% of the laboratory claim reimbursements paid to PMC, including the reimbursements from Prescribe Recovery. PMC’s payment of 78% of laboratory reimbursements to US Med Sci Indiana induced them (as the lab manager) to direct Prescribe Recovery’s lab referrals to PMC, and violated the Anti-Kickback Statute.

Collectively, these civil healthcare fraud settlements return more than $7.2 million to the Medicare, Kentucky Medicaid, and TRICARE programs. For their roles in the scheme as the laboratories submitting the false claims, PMC agreed to pay $5,219,000 and Bluewater Toxicology agreed to pay $895,952. Sturgeon and Moore, agreed to pay $713,466 and $40,000, respectively, to resolve their liability. Arthur agreed to pay $5,500 to resolve his liability; and Dr. and Mrs. Merced collectively agreed to pay $450,000 to resolve their liability, under the False Claims Act and Dr. Merced’s liability for separate conduct under the Controlled Substances Act. The value of Moore’s, Arthur’s, and the Merceds’ settlements included factoring in their inability to pay, based on financial disclosures.

“Through a complex patchwork of schemes, the federal government was defrauded out of millions of dollars,” said Carlton S. Shier, IV, United States Attorney for the Eastern District of Kentucky. “This money was appropriated to provide medical services to eligible Americans; instead, it improperly yielded proceeds to those who were submitting false claims. When fraud and abuse deplete these valuable resources, it injures all of us. With the assistance of our partners and the filing of a qui tam complaint, vital resources are now being returned to their intended purpose.”

“Individuals and entities participating in the federal health care system must comply with laws designed to protect program funds and ensure patients receive appropriate, quality care,” said Special Agent in Charge Kelly J. Blackmon of the U.S. Department of Health and Human Services Office of Inspector General (HHS-OIG). “We will continue to collaborate with our law enforcement partners to hold health care providers accountable for improper payments from federal health care programs.”

The settlements resolve a lawsuit brought by a private citizen under the qui tam provisions of the False Claims Act. Under those provisions, a private party can file a civil action on behalf of the United States, thereby bringing allegations of fraud to the Government’s attention, and share in any financial recovery. As part of this resolution, the individuals who filed the qui tam complaint will receive a portion of the settlement proceeds. The civil case is captioned United States ex rel. Clark et al. v. United States Medical Scientific, LLC, et al. , Case No. 0:18-cv-109-KKC.

The settlement agreements resulted from the joint efforts of the United States Attorney’s Office for the Eastern District of Kentucky; U.S. Department of Health and Human Services, Office of Inspector General; U.S. Drug Enforcement Administration; U.S. Department of Defense, Office of the Inspector General, Defense Criminal Investigative Service; and the Kentucky Attorney General’s Office of Medicaid Fraud and Abuse Control . The United States was represented by Assistant U.S. Attorney Meghan Stubblebine. The claims resolved by the settlements are allegations only, and there has been no determination of liability.

CONTACT: Gabrielle Dudgeon

PHONE: (859) 685-4887

E-MAIL: [email protected]

Rocket Lab Completes Second Spacecraft for Varda Space Industries, Advancing In-Space Manufacturing

Long Beach, Calif. September 26, 2024 – Rocket Lab USA, Inc. (Nasdaq: RKLB) (“Rocket Lab” or “the Company”), a global leader in launch services and space systems, has completed testing and integration of its second Pioneer spacecraft for Varda Space Industries, Inc. (“Varda”), the world's first in-space pharmaceutical processing and hypersonic Earth re-entry logistics company.

Rocket Lab’s first Pioneer spacecraft for Varda was launched in June 2023. Varda successfully crystallized the HIV drug Ritonavir while on orbit and Rocket Lab and Varda successfully landed the re-entry capsule in the Utah desert in February 2024. The Company is now preparing Varda’s second mission during which Rocket Lab and Varda will once again conduct in-space operations, reentry positioning maneuvers, and deorbiting to recover Varda’s capsule. Varda received permission from the FAA under a Part 450 license earlier this month, making them the only company to ever secure a second reentry license.

Designed and built at Rocket Lab’s Spacecraft Production Complex and Headquarters in Long Beach, California, the Pioneer spacecraft will provide power, communications, propulsion, and attitude control for Varda’s 120 kg reentry capsule. Each Pioneer spacecraft leverages the company’s vertically integrated spacecraft components and subsystems, including star trackers, reaction wheels, solar panels, flight software, and radios.

“By leveraging Rocket Lab’s vertically integrated approach to spacecraft production, we can rapidly develop and deliver the highly capable and reliable spacecraft that Varda needs for their missions,” said Rocket Lab Founder and CEO, Sir Peter Beck. “This close collaboration allows us to push the boundaries of innovation, enabling Varda to create high-value products in microgravity and bring them back to Earth. We’re excited to work alongside Varda as they revolutionize manufacturing processes and open new markets through space.”

"Our partnership with Rocket Lab demonstrates the power of collaboration to evolve the orbital economy," said Varda CEO and co-founder Will Bruey. "Each reentry is a remarkable milestone that paves the way for future innovations, and the day when reentry is as common as launch"

Rocket Lab’s Pioneer spacecraft is a flight proven highly configurable medium delta-V platform designed to support large payloads, re-entry capabilities, and dynamic space operations.

Learn more about Rocket Lab and Varda’s partnership: Varda Space Industries | Rocket Lab (rocketlabusa.com)

+ Rocket Lab Media Contact

Lindsay McLaurin

media@rocketlabusa.com

+ About Rocket Lab

Rocket Lab is a global leader in launch and space systems. Rocket Lab’s Electron launch vehicle is the second most frequently launched U.S. rocket annually and has delivered more than 197 satellites to orbit for commercial and Government partners, including NASA, the U.S. Air Force, DARPA and the NRO. Rocket Lab also delivers proven suborbital hypersonic launch capability with its HASTE launch vehicle. Building on the deep heritage of Electron, Rocket Lab is developing Neutron, an advanced 13-tonne payload class, reusable launch vehicle tailored for constellation deployment and interplanetary missions. Rocket Lab is also a premier supplier of advanced satellites, flight-proven subsystems and spacecraft components. At a component level, Rocket Lab spacecraft technology spans space solar power, composite structures, flight software, star trackers, reaction wheels, separation systems, and more. Rocket Lab satellite technology and components have been integrated into more than 1,700 satellite missions globally. www.rocketlabusa.com .

+ Forward Looking Statements

This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. We intend such forward-looking statements to be covered by the safe harbor provisions for forward looking statements contained in Section 27A of the Securities Act of 1933, as amended (the “Securities Act”) and Section 21E of the Securities Exchange Act of 1934, as amended (the “Exchange Act”). All statements contained in this press release other than statements of historical fact, including, without limitation, statements regarding our launch and space systems operations, launch schedule and window, safe and repeatable access to space, Neutron development, operational expansion and business strategy are forward-looking statements. The words “believe,” “may,” “will,” “estimate,” “potential,” “continue,” “anticipate,” “intend,” “expect,” “strategy,” “future,” “could,” “would,” “project,” “plan,” “target,” and similar expressions are intended to identify forward-looking statements, though not all forward-looking statements use these words or expressions. These statements are neither promises nor guarantees, but involve known and unknown risks, uncertainties and other important factors that may cause our actual results, performance or achievements to be materially different from any future results, performance or achievements expressed or implied by the forward-looking statements, including but not limited to the factors, risks and uncertainties included in our Annual Report on Form 10-K for the fiscal year ended December 31, 2023, as such factors may be updated from time to time in our other filings with the Securities and Exchange Commission (the “SEC”), accessible on the SEC’s website at www.sec.gov and the Investor Relations section of our website at www.rocketlabusa.com, which could cause our actual results to differ materially from those indicated by the forward-looking statements made in this press release. Any such forward-looking statements represent management’s estimates as of the date of this press release. While we may elect to update such forward-looking statements at some point in the future, we disclaim any obligation to do so, even if subsequent events cause our views to change.

Varda Media Contact:

Media@varda.com

About Varda:

Varda Space Industries is expanding the economic bounds of humankind by designing and building the infrastructure needed to make low Earth orbit accessible to industry, from in-orbit production equipment to reliable and economical reentry capsules. The company operates out of El Segundo, California with office and industrial production space. You can follow Varda on X (@vardaspace) and LinkedIn.

More News From Rocket Lab

Rocket Lab Successfully Launches 53rd Electron Mission, Deploys Another Five Satellites for Kinéis

Rocket Lab Appoints Chief Operations Officer to Support Company Growth

Rocket Lab Sets Launch Date for Second Dedicated Kinéis Mission to Deploy IoT Constellation

Rocket Lab Ships Twin Satellites to Launch Site for NASA Mars Mission

Rocket Lab Begins Installation of Large Carbon Composite Rocket-Building Machine

Rocket Lab Completes Successful First Hot Fire of Archimedes Engine for Neutron Rocket

First-Year Admissions
Transfer Admissions
Financial Aid
Graduate Admissions
Medical Education Admissions
International Admissions
Tours & Open Houses
Online Learning
Degree Completion
Colleges & Schools
Degrees & Programs
Courses, Schedules & Registration
Student Success
International
Winter & Summer Sessions
Camden Campus
Rowan University Libraries
The Arts at Rowan
Athletics & Sports Recreation
Health & Safety
Housing & Dining
Technology on Campus
Entertainment & Culture
Rowan Thrive
Cooper Medical School of Rowan University (MD)
Virtua Health College of Medicine & Life Sciences (DO)
Shreiber School of Veterinary Medicine (DVM)
Office of Research
Research Centers & Institutes
South Jersey Technology Park
Research News
Military/Veterans
Our Past, Present & Future
Visiting Rowan
Working at Rowan
Rowan Fast Facts
Giving to Rowan
News & Events

Job Postings

Welcome to rowan university’s career site.

A top 100 national public research institution, Rowan University offers bachelor’s through doctoral and professional programs in person and online to 22,000 students through its main campus in Glassboro, N.J., its medical school campuses in Camden and Stratford, and five others. The University has earned national recognition for innovation, commitment to high-quality, affordable education, and developing public-private partnerships. A Carnegie-classified R2 (high research activity) institution, Rowan has been recognized as the fourth fastest-growing public research university, as reported by The Chronicle of Higher Education. For more information on Rowan University, click here

All positions are contingent upon budget appropriations.

Please send any inquiries to [email protected]

Lab Technician (Strich Lab), Department of Molecular Biology, Rowan-Virtua School of Translational Biomedical Engineering & Sciences

Apply now Job no: 499969 Work type: Regular Full-Time Location: Stratford, New Jersey Categories: Laboratory

Under direction, performs and assists with technical laboratory procedures and analyses in support of specialized research activities of the laboratory. Assists in the set-up and execution of experiments as required. Performs other related laboratory duties as described below.

ESSENTIAL DUTIES AND RESPONSIBILITIES include the following. Other duties may be assigned.

As assigned, performs various research and technical procedures, as well as assists in the establishment of new methodologies and instrumentation use.

Assists in preparing culture media, reagents, buffers, and stock solutions.

Assists in ordering laboratory supplies, maintaining chemical inventories, and other lab-related administrative duties.

Prepares reports and documents related to experimental methods and results and maintains accurate records of experimentation and research.

Experience in molecular biology and biochemistry techniques including, but not limited to, buffer preparation, electrophoresis, and chromatography.

Understands and adheres to legacy Rowan-SOM compliance standards as they appear in the Corporate Compliance Policy, Code of Conduct and Conflict of Interest Policy.

Keeps abreast of all federal, state and Rowan University regulations, laws and policies as they presently exist and as they change or are modified.

Performs other duties as assigned.

QUALIFICATIONS:

To perform this job successfully, an individual must be able to perform each essential duty satisfactorily. The requirements listed above are specific for the knowledge, skill, and/or ability required. Reasonable accommodations may be made to enable individuals with disabilities to perform the essential functions.

EDUCATION and/or EXPERIENCE:

Bachelors' Degree in a relevant field such as Biochemistry, Biology, Chemistry, Chemical Biology, Molecular Biology, Biophysics, or Neuroscience. Previous research experience is desirable.

Only completed, online applications submitted on or before the deadline will be considered.
Candidates must be legally authorized to work in the US, and the university will not sponsor an applicant for a work visa for this position.

Advertised: Sep 26 2024 Eastern Daylight Time Applications close: Oct 9 2024 11:55 PM Eastern Daylight Time

Back to search results Apply now Refer a friend

We will email you new jobs that match this search.

Great, we can send you jobs like this, if this is your first time signing up, please check your inbox to confirm your subscription.

The email address was invalid, please check for errors.

You must agree to the privacy statement

Search results

Position	Location	Closes
	Stratford, New Jersey
Under direction, performs and assists with technical laboratory procedures and analyses in support of specialized research activities of the laboratory. Assists in the set-up and execution of experiments as required. Performs other related laboratory duties as described below.

Current Opportunities

-->

Position	Location	Closes
	Stratford, New Jersey

About Rowan University

Now celebrating its Centennial, Rowan focuses on practical research at the intersection of engineering, medicine, science, and business while ensuring excellence in undergraduate education. The University has earned national recognition for innovation, commitment to high-quality and affordable education, and developing public-private partnerships. A Carnegie-classified R2 (high research activity) institution, Rowan has been recognized as the fourth fastest-growing public research university, as reported by The Chronicle of Higher Education.

Non-Discrimation at Rowan University

Rowan University celebrates diversity and is committed to creating an inclusive environment for all employees. All qualified applicants will receive consideration for employment without regard to age, ethnicity, race, religion, sex, gender identity or expression, genetic information, marital status, national origin, (dis)ability status, military status, and other NJ protected classes. Rowan University does not discriminate on the basis of sex in its educational programs and activities, including employment as required by Title IX. Rowan is committed to providing access, equal opportunity, and reasonable accommodation for individuals with (dis)abilities.

To request reasonable accommodation, contact Christy Mroz, Administrative Assistant, [email protected], 856-256-5494. Rowan strongly encourages applicants from underrepresented groups to apply.

Pursuant to Title IX of the Education Amendments of 1972 and supporting regulations, Rowan does not discriminate on the basis of sex in the education programs or activities that it operates; this extends to admission and employment. Inquiries about the application of Title IX and its supporting regulations may be directed to the Assistant Secretary for Civil Rights, Office for Civil Rights, U.S. Department of Education, or to the University’s Title IX Coordinator, Office of Student Equity & Compliance, Rowan University, Hawthorne Hall, Suite 312, 201 Mullica Hill Rd, Glassboro, NJ 08028, [email protected] , 856-256-5440.

For information on the Title IX Sexual Harassment/Sexual Assault policy and grievance procedures, please click here .

More Information

Rowan University is subject to the residency requirements of the NJ First Act (N.J.S.A. 52:14-7, P.L. 2011, Chapter 70). Any person hired to a non-exempt position shall either have their principal residence in New Jersey or have one (1) year from the date of employment to establish, and then maintain, principal residence in the State of New Jersey. Any person hired to an exempt position shall either have their principal residence in New Jersey, Delaware, Pennsylvania, or New York or have ninety (90) days from the date of employment to establish, then maintain, principal residence in the State of New Jersey, Delaware, Pennsylvania, or New York.

Rowan University is committed to assisting all members of the Rowan community in providing for their own safety and security. The Annual Security and Fire Safety Report is available on the Department of Public Safety website at: https://sites.rowan.edu/publicsafety/_docs/annual_security_report.pdf

If you would like to receive a hard copy of the Annual Security and Fire Safety Report which contains this information, you can stop by the Department of Public Safety Office, located at Bole Hall Annex, 201 Mullica Hill Road, Glassboro, NJ 08028 or you can request that a copy be mailed to you by calling (856) 256-4562 or 4506.

The report contains information regarding campus security and personal safety including topics such as: crime prevention, public safety authority, crime reporting policies, fire safety, disciplinary procedures and other matters of importance related to security on campus. The report also contains information about fire statistics in Rowan University Residential Facilities and crime statistics for the three previous calendar years concerning reported crimes that occurred on campus; in certain off-campus buildings or property owned or controlled by the University; and on public property within, or immediately adjacent to and accessible from the campus. This information is required by federal law, Jeanne Clery Disclosure of Campus Security Policy and Campus Crime Statistics Act or "Clery Act" and is provided by the Rowan University Department of Public Safety.

Position Search

Filter results.

Regular Full-Time 1
Stratford, New Jersey 1
Laboratory 1
Rowan on Twitter
Rowan on Facebook
Rowan on Instagram
Rowan on YouTube
Rowan on Flickr

Rowan University • 201 Mullica Hill Road • Glassboro, New Jersey 08028 • 856-256-4000

Read the Notice of Availability of Rowan’s Annual Security & Fire Safety Report

IMAGES

Atomic and Molecular Laser Spectroscopy Laboratory
Building a Spectroscopy High Resolution Experiment
Understanding Spectrometry and Spectroscopy
Atomic and Molecular Laser Spectroscopy Laboratory
Atomic and Molecular Laser Spectroscopy Laboratory
Laboratory of photoluminescence spectroscopy

VIDEO

Gamma Ray Spectroscopy Advanced Lab
NMR Spectroscopy Experiment S21
Infrared Spectroscopy: Tips & Tricks
Infrared spectroscopy experiment
Introduction to Spectroscopy
LIBS spectroscopy experiment Laser Laboratory IPN-CICATA Altamira

COMMENTS

PDF Experiment 2: INTRODUCTION TO SPECTROSCOPY
EXPERIMENT 2: INTRODUCTION TO SPECTROSCOPYIn Part One of this experiment you will be intr. duced to the fundamentals of spectroscopy. You will first learn how to properly use a Spectronic 20 instrument and then you will use the instrument to find the wavelength (λ) at which absorbance of light by a solution of food.
PDF Module 1: Fundamentals of Spectroscopy
This module is designed to introduce the basic concepts of spectroscopy and to provide a survey of several of the most common types of spectroscopic measurement. You will conduct the following measurements. UV-VIS (ultraviolet-visible) spectroscopy of electronic states. Fluorescence spectroscopy of electronic states.
PDF Exp 8
The purpose of this laboratory experiment is for you to gain hands-on experience in the operation of an infrared (IR) spectrometer and interpretation of IR spectra to elucidate structural details. This experiment will supplement the theoretical aspects of IR spectroscopy discussed in lecture. The information provided below was written to be ...
PDF Experiment 11
Experiment 11 — Infrared Spectroscopy _____ Pre-lab preparation. (1) In Ch 5 and 12 of the text you will find examples of the most common functional groups in organic molecules. In your notebook, provide generic examples of the following compound classes: (a) alkane, (b) alkene, (c) alkyne, (d) alkyl halide, (e) alcohol, (f) ...
Lab #7: Analyzing Light: The Spectroscope
S p e c tr o s c o p e. The spectroscope in the picture is the updated spectroscope that is now in the kits. The entire light spectrum (also known as the electromagnetic spectrum) span light waves that are miles long to waves that are extremely short. The light we see (visible light) only spans about 1.5% of then entire light spectrum.
Lab 10: Spectroscopy
Using spectroscopy (also called spectral analysis, spectrometry, or spectrophotometry), we will examine emission and absorption of light by various substances. Spectrometers (also called spectrophotometers) are measurement tools designed to distinguish different colors of light. The spectrometers we will use in this lab detect the intensity of ...
PDF Experiment: Spectroscopy
Experiment: Spectroscopy Introduction to light Light is a form of energy called electromagnetic radiation. A chart of the electromagnetic spectrum is shown below. ... Spectroscopy Lab Partner _____ Data and Questions Part 1 Flame tests for known elements Metal Ion Color of flame ...
PDF EXPERIMENT 3: Introduction to Spectroscopy
EXPERIMENT 3: Introduction to Spectroscopy. Background (Read your text to review electromagnetic energy) The word spectroscopy is used to refer to the broad area of science dealing with the absorption, emission, or scattering of electromagnetic radiation by molecules, ions, atoms, or nuclei. Spectroscopic techniques are probably the most widely ...
Intro to Spectroscopy Lab Report
Intro to Spectroscopy Lab Report Introduction. Spectroscopy is the study of absorption and emission of electromagnetic radiation through matter. The process involves splitting light into its constituent wavelengths creating a line spectrum which reveals a wealth of information about the properties of elements and molecules.
Raman Spectroscopy
Description. Raman spectroscopy uses the inelastic scattering of monochromatic light to probe molecular structure. In Raman scattering, the frequency of the scattered light is shifted from the frequency of the incident beam. The rotational and vibrational energy levels of the molecule in question determine the magnitude of the frequency shift.
Physics 204
This experiment will introduce you to one of the most powerful tools from physics: Optical Spectroscopy. ... Spectroscopy. It has applications in nearly every field of science, from medicine to engineering to interior design! Spectroscopy is generally meant to describe the process of ... or energies. An example: If you remember the first lab of ...
PDF Introduction to spectroscopy
spectroscopy to find out the chemical constitution of known and unknown gases. The same procedure is used for starlight, telling us what its source is composed of. The baseline is a laboratory experiment with known materials, and later we can compare the unknown to what we already know.
Spectroscopy Lab
EnMAP (Environmental Mapping and Analysis Program) is a high-resolution imaging spectroscopy remote sensing mission that was successfully launched on April 1st, 2022. Equipped with a prism-based dual-spectrometer, EnMAP performs observations in the spectral range between 418.2 nm and 2445.5 nm with 224 bands and a high radiometric and spectral ...
MIT Spectroscopy Lab
The George R. Harrison Spectroscopy Laboratory of the Massachusetts Institute of Technology is engaged in research in the field of modern optics and spectroscopy for the purpose of furthering fundamental knowledge of atoms and molecules and pursuing advanced engineering biomedical applications.
Spectroscopy
Laboratory Spectroscopy Researchers also do spectroscopy in the lab, studying the spectrum of different elements and molecules under a variety of conditions. For example, experiments have determined that the relative strength of two emission lines in a spectrum provides an independent test of the temperature and density of the atoms making that ...
Sensitive and reliable lab-on-paper biosensor for label-free ...
A new, sensitive, and cost-effective lab-on-paper-based immunosensor was designed based on electrochemical impedance spectroscopy (EIS) for the detection of exosomes. EIS was selected as the determination method since there was a surface blockage in electron transfer by binding the exosomes to the transducer. Briefly, the carbon working electrode (WE) on the paper electrode (PE) was modified ...
PPRI seeks faculty-student bids for unique State Department policy
WEST LAFAYETTE, Ind. — The Purdue Policy Research Institute (PPRI) is inviting proposals for participation in the spring 2025 Diplomacy Lab, a U.S. Department of State initiative that connects with academic institutions to address real-world policy challenges. Through the PPRI Diplomacy Lab initiative, students can gain valuable learning opportunities while giving the State Department fresh ...
Hospital, Laboratory, Referring Physician, and Lab Employees Pay More
LEXINGTON, Ky. — A hospital, a laboratory, three lab employees, and a referring physician and his office manager have agreed to collectively pay the United States more than $7.2 million dollars to resolve civil allegations that they defrauded federal healthcare programs in connection with laboratory tests that were not medically necessary or were tainted by violations of the federal Anti ...
Rocket Lab's stock soars as KeyBanc raises price target
Rocket Lab USA Inc.'s shares ended Friday's session up 12.5%, boosted by KeyBanc Capital Markets' price-target hike for the space-launch company. In a note released Thursday, KeyBanc Capital ...
Rocket Lab Completes Second Spacecraft for Varda Space Industries
Long Beach, Calif. September 26, 2024 - Rocket Lab USA, Inc. (Nasdaq: RKLB) ("Rocket Lab" or "the Company"), a global leader in launch services and space systems, has completed testing and integration of its second Pioneer spacecraft for Varda Space Industries, Inc. ("Varda"), the world's first in-space pharmaceutical processing and hypersonic Earth re-entry logistics company.
Rowan HR
Welcome to Rowan University's Career Site. A top 100 national public research institution, Rowan University offers bachelor's through doctoral and professional programs in person and online to 22,000 students through its main campus in Glassboro, N.J., its medical school campuses in Camden and Stratford, and five others.