AL | Science News


physicians time in making a treatment decision and helps improve patient care.


The test is the first quantitative HCV RNA assay to be approved for use as an aid in diagnosis for active HCV infection. This expanded indication is in addition to its approved use as a viral load test to help physicians assess a patient’s response to antiviral therapy.


Lab Technology, Analysis and Biotechnology are Focus of analytica Anacon India/India Lab Expo


Hyderabad, India, is the setting for analytica Anacon India and India Lab Expo (October 20–22, 2016). Key exhibitor segments to be featured are Analysis, Biotechnology, Laboratory Equipment, Quality Control/ Measurement and Testing and Clinical Diagnostics.


The events will attract a wide range of attendees from the pharmaceutical, food and beverage, material science, biotechnology, chemical processing, healthcare diagnostics and environmental sectors. Visitors from research laboratories, universities, government agencies, clinical research laboratories and contract laboratories will also be on hand.


Please visit www.indialabexpo.com for more information.


New Method Uses GC to Examine Lipstick Samples for Forensic Analysis


Raman spectroscopy and X-ray diffraction are two techniques currently employed to remove lipstick samples from crime scenes and analyze their chemical constituents. But in underfunded forensic laboratories, such methods, which require specialized equipment and training, may be limited.


To improve on this, researchers at Western Illinois University started with an established lipstick sample extraction technique and then


added an organic solvent to remove oils and waxes, and a basic organic solvent to extract the residue.


The team selected 40 lipsticks and made marks with them on paper to simulate lipstick smears found at the scene of a crime. Different brands have unique compositions of organic molecules, which give distinct chromatography signals. The study shows that the spectra of crime scene lipstick can be compared to those of known lipsticks, which are compiled in a database. Once the brand is identified, law enforcement officials can investigate whether a suspect uses that particular cosmetic.


While analyses are still being conducted, the researchers say that the most optimal results have been obtained with the GC technique versus thin layer chromatography (TLC) and high- performance liquid chromatography (HPLC).


Laser-Based Absorption Technique Detects Microbial Growth in Food


Researchers have developed a rapid, noninvasive method to monitor bacterial growth in packaged foods. The technique is based on tunable diode laser absorption spectroscopy (TDLAS), which combines the most optimal properties of noninvasive optical spectrometry, namely, high sensitivity and the ability to provide results in real time. “One major advantage TDLAS offers is its ability to achieve very low detection limits, on the order of parts per billion,” said Jie Shao, associate professor at Zhejiang Normal University. “Apart from concentration, it’s also possible to determine other properties of the gas under observation—temperature, pressure, velocity and mass flux.”


The instrument comprises a tunable diode laser as the light source, beam shaping optics, the sample to be investigated, receiving optics and one or more detectors. “The emission wavelength of the laser is tuned over a characteristic absorption line transition—of the species within the gas being assessed,” Shao explained. “This causes a reduction of the measured signal intensity, which we


AMERICAN LABORATORY 7 APRIL 2016


can use to determine the gas concentration.” When the wavelength is rapidly tuned across the transition in a specific manner, it can be combined with wavelength modulation (WM), which enhances the sensitivity of TDLAS.


The WM-TDLAS method is truly noninvasive, making it ideal for monitoring the status of food and medical supplies, or determining under which environmental conditions bacterial growth is expected to be severe.


Microwave Imaging Allows Scientists to Study Processes in Reactive, Toxic or


Radioactive Environments


A novel technique uses microwaves to nondestructively image reactive and biological samples at nanoscale levels under realistic conditions. Key to the method, developed by researchers at the Center for Nanoscale Science and Technology at the National Institute of Standards and Technology (NIST) and the Department of Energy’s Oak Ridge National Laboratory (ORNL), is an ultrathin membrane that separates the needle-like probe of an atomic force microscope (AFM) from the underlying sample, held in small containers that maintain a consistent liquid or gas environment.


The method extends the applications of near-field microwave imaging beyond semiconductor technology, where it is used to study solid structures, to liquids and gases.


Using the new microscope, researchers were able to observe the early stages of a silver electroplating process. Microwave imaging captured the electrochemical formation of dendrites on electrodes, and features nearly as small as 100 nm could be seen. The low- energy microwaves did not damage chemical bonds or otherwise disrupt the process during imaging. By way of contrast, a scanning electron microscope used to record the same electroplating process at comparable levels of resolution yielded images that showed destructive effects of the electron beam.


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