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Alan J Bergmann, Gary L Points, Richard P Scott, Glenn Wilson, Kim A Anderson
With hundreds of thousands of chemicals in the environment, effective monitoring requires high-throughput analytical techniques. This paper presents a quantitative screening method for 1550 chemicals based on statistical modeling of responses with identification and integration performed using deconvolution reporting software. The method was evaluated with representative environmental samples. We tested biological extracts, low-density polyethylene, and silicone passive sampling devices spiked with known concentrations of 196 representative chemicals...
March 19, 2018: Analytical and Bioanalytical Chemistry
Ekaterina N Lazareva, Valery V Tuchin
This study is focused on the measurements of the refractive index of hemoglobin solutions in the visible/near-infrared (NIR) spectral range at room temperature for characteristic laser wavelengths: 480, 486, 546, 589, 644, 656, 680, 930, 1100, 1300, and 1550 nm. Measurements were performed using the multiwavelength Abbe refractometer. Aqua hemoglobin solutions of different concentrations obtained from human whole blood were investigated. The specific increment of refractive index on hemoglobin concentration and the Sellmeier coefficients were calculated...
March 2018: Journal of Biomedical Optics
Yun Gao, Guodong Zhou, Ni Zhao, Hon Ki Tsang, Chester Shu
Waveguide photodetectors integrated with graphene have demonstrated potential for ultrafast response and broadband operation. Here, we demonstrate high-performance chemical vapor deposited graphene-on-silicon nitride waveguide photodetectors by enhancing the absorption of light propagating in the transverse-magnetic mode through a metal-graphene junction. A doubling in responsivity is experimentally observed. In our zero-biased metal-graphene junction, a 15  mA W-1 intrinsic responsivity and a 30 GHz bandwidth are achieved at ∼1550  nm...
March 15, 2018: Optics Letters
Rémi Patouret, Christelle Doebelin, Ruben D Garcia-Ordonez, Mi Ra Chang, Claudia Ruiz, Michael D Cameron, Patrick R Griffin, Theodore M Kamenecka
Crystallography has identified stearic acid, ALRT 1550 and ATRA as ligands that bind RORβ, however, none of these molecules represent good starting points to develop optimized small molecule modulators. Recently, Compound 1 was identified as a potent dual RORβ and RORγ inverse agonist with no activity towards RORα (Fig. 1). To our knowledge, this is one of only two small molecule RORβ inverse agonists identified in the primary literature from a tractable chemical series and represents an ideal starting point from which to design RORβ-selective modulators...
March 3, 2018: Bioorganic & Medicinal Chemistry Letters
Zhenju Wan, Jinxia Feng, Yuanji Li, Kuanshou Zhang
Phase quadrature squeezed states at 1550 nm generated from degenerate optical parametric amplifiers (DOPAs) using periodically poled KTiOPO4 (PPKTP) and periodically poled lithium niobate (PPLN) are compared. A squeezing of 6.8 dB was produced from the DOPA using PPKTP with the phase matching temperature of 34.5 °C. By contrast, a measured squeezing of 4.9 dB was generated using PPLN with the phase matching temperature of 135.2 °C. The degradation of squeezing using a nonlinear crystal with a high phase matching temperature is explained by a theoretical model of DOPAs including the extra phase noise caused by the guided acoustic wave Brillouin scattering within the nonlinear crystal...
March 5, 2018: Optics Express
Mahima Bansal, Manisha Sharma, Chris Bullen, Darren Svirskis
We report the fabrication of PEDOT films using vapour phase polymerisation with Fe(III)tosylate as the oxidant and to provide the doping ion. Multiple polymerisation steps resulted in the formation of free-standing PEDOT films. The PEDOT films were highly conductive, a single layer was 1840±50S/cm with a small decrease in conductivity for the five layered films to 1550±60S/cm. The five-layered films were flexible and freestanding in air with a thickness of 1.66±0.06μm. The ability of the freestanding PEDOT films to act as electrically tuneable rate controlling membranes was determined for nicotine (MW 162...
March 1, 2018: Materials Science & Engineering. C, Materials for Biological Applications
Rajendiran Karthikraj, Sonali Borkar, Sunmi Lee, Kurunthachalam Kannan
The exposure of pets, such as dogs and cats, to a wide range of chemicals present in the indoor environment and the concomitant increase in noninfectious diseases in these companion animals are a concern. Nevertheless, little is known about the sources and pathways of exposure to chemicals in pets. In this study, we determined the concentrations of parabens in commercially available cat and dog foods as well as in urine samples from these pets collected from the Albany area of the state of New York in the United States...
March 7, 2018: Environmental Science & Technology
Alem Gebru, Samuel Jansson, Rickard Ignell, Carsten Kirkeby, Jord C Prangsma, Mikkel Brydegaard
We present a dual-wavelength polarimetric measurement method to distinguish species and sexes of disease transmitting mosquitoes in flight. By measuring co- and de-polarized backscattered light at 808 and 1550 nm, the degree of linear polarization, wingbeat frequency, reflectance, spectral ratio and glossiness of mosquitoes can be retrieved. Body and wing contributions to these signals can be separated. Whereas the optical cross-section is sensitive to the aspect of observation, thus the heading direction of the insect in flight, we demonstrate that polarimetric- and spectral- band ratios are largely invariant to the aspect of observation...
March 5, 2018: Journal of Biophotonics
E Pavlenko, A Barbova, A Hovhannesyan, Z Tsenilova, A Slavuckij, B Shcherbak-Verlan, A Zhurilo, E Vitek, G Skenders, I Sela, A M Cabibbe, D M Cirillo, P de Colombani, M Dara, A Dean, M Zignol, A Dadu
SETTING: The true prevalence of multidrug-resistant tuberculosis (MDR-TB) in Ukraine is not known. Available data are a decade old and limited to only one province. OBJECTIVE: To determine the prevalence of MDR-TB among new and previously treated TB cases in Ukraine and explore the risk factors associated with drug resistance. METHODS: A total of 1550 sputum smear-positive pulmonary TB patients were recruited from 40 clusters throughout Ukraine...
February 1, 2018: International Journal of Tuberculosis and Lung Disease
Ahmed Elsherif, Rachel Gaulton, Jon Mills
Vegetation water content, quantified as the leaf equivalent water thickness (EWT), can serve as an indicator of vegetation stress. The intensity data recorded by terrestrial laser scanning (TLS) instruments, operating at shortwave infrared wavelengths, can be used to estimate the three-dimensional distribution of EWT, after a full and rigorous calibration for the range and incidence angle effects. However, TLS instruments do not record the incidence angles automatically, making calibration challenging. In this study, intensity data from two commercially available TLS instruments (Leica P40, 1550 nm shortwave infrared wavelength, and Leica P20, 808 nm near-infrared wavelength) were combined in a normalized difference index (NDI)...
April 6, 2018: Interface Focus
Chaoqun Jiang, Yang Li, Qiancheng Liu, Xianming Zhou, S N Luo
Conventional fiber-optic displacement interferometers operated at 1550 nm suffer from low temporal or velocity resolution for lower velocity measurements. To overcome this drawback, a fiber-optic Doppler pin system operated at 532 nm is developed, and its capability is demonstrated with low-velocity plate impact experiments. The new instrument would be an important supplemental to the existed systems.
February 2018: Review of Scientific Instruments
Andrew Michaels, Eli Yablonovitch
Efficient coupling between integrated optical waveguides and optical fibers is essential to the success of silicon photonics. While many solutions exist, perfectly vertical grating couplers that scatter light out of a waveguide in the direction normal to the waveguide's top surface are an ideal candidate due to their potential to reduce packaging complexity. Designing such couplers with high efficiencies, however, has proven difficult. In this paper, we use inverse electromagnetic design techniques to optimize a high efficiency two-layer perfectly vertical silicon grating coupler...
February 19, 2018: Optics Express
Haroon Asghar, Wei Wei, Pramod Kumar, Ehsan Sooudi, John G McInerney
We report experimental studies of the influence of symmetric dual-loop optical feedback on the RF linewidth and timing jitter of self-mode-locked two-section quantum dash lasers emitting at 1550 nm. Various feedback schemes were investigated and optimum levels determined for narrowest RF linewidth and low timing jitter, for single-loop and symmetric dual-loop feedback. Two symmetric dual-loop configurations, with balanced and unbalanced feedback ratios, were studied. We demonstrate that unbalanced symmetric dual loop feedback, with the inner cavity resonant and fine delay tuning of the outer loop, gives the narrowest RF linewidth and reduced timing jitter over a wide range of delay, unlike single and balanced symmetric dual-loop configurations...
February 19, 2018: Optics Express
Ruiying Xu, Yongchao Li, Fan Zheng, Guanghao Zhu, Lin Kang, Labao Zhang, Xiaoqing Jia, Xuecou Tu, Qingyuan Zhao, Biaobing Jin, Weiwei Xu, Jian Chen, Peiheng Wu
Polarization sensitive photo-detectors are the key to the implementation of the polarimetric imaging systems, which are proved to have superior performance than their traditional counterparts based on intensity discriminations. In this article, we report the demonstration of a superconducting nanowire single photon detector (SNSPD) of which the response is ultra-sensitive to the polarization state of the incident photons. Measurements carried out on a fabricated SNSPD show that a device efficiency of ~48% can be achieved at 1550 nm for the case of parallel polarization, which is ~420 times larger than that for the case of perpendicular polarization...
February 19, 2018: Optics Express
Yifei Wang, Md Azahar Ali, Edmond K C Chow, Liang Dong, Meng Lu
The rapid growth of point-of-care tests demands for biosensors with high sensitivity and small size. This paper demonstrates an optofluidic metasurface that combines silicon-on-insulator (SOI) nanophotonics and nanofluidics to realize a high-performance, lateral flow-through biosensor. The metasurface is made of a periodic array of silicon nanoposts on an SOI substrate, and functionalized with specific receptor molecules. Bonding of a polydimethylsiloxane slab directly onto the surface results in an ultracompact biosensor, where analyte solutions are restricted to flow only in the space between the nanoposts...
February 17, 2018: Biosensors & Bioelectronics
Ji Sun, Yue Zhou, Yitang Dai, Jianqiang Li, Feifei Yin, Jian Dai, Kun Xu
In this paper, we build a mode-locked all-polarization-maintaining figure-of-8 erbium-doped fiber oscillator based on a nonlinear amplifying loop mirror. The fiber oscillator can generate 1.6 ps chirped pulses that can be de-chirped to 500 fs at 1550 nm with a pulse energy of 0.8 nJ and a repetition rate of 12 MHz. It can be further amplified up to 10 nJ and compressed down to 100 fs with a pre-chirp managed nonlinear amplification setup. Such an oscillator and amplifier configuration has the advantages of self-starting and long-term operation, and it is highly suitable for subsequent frequency conversion, which is desirable for many applications in ultrafast microscopy and precision spectroscopy...
February 20, 2018: Applied Optics
Alan Zhan, Taylor K Fryett, Shane Colburn, Arka Majumdar
Arrays of wavelength scale scatterers are a promising platform for designing optical elements with a compact footprint. The large number of degrees of freedom in this system allows for unique and plentiful functionalities. However, the many variables also create a complex design problem. While intuitive forward design methods work for simple optical elements, they often fail to produce complicated elements, especially those involving multiple elements. We present an inverse design methodology for large arrays of wavelength scale spheres based on both adjoint optimization or sensitivity analysis and generalized multi-sphere Mie theory as a solution to the design problem...
February 20, 2018: Applied Optics
Sanaa E Tork, Magda M Aly, Omar Elsemin
In the current study, the purified l-glutaminase from Streptomyces pratensis NRC10 (GenBank number KC857622) was characterized. Its molecular weight was estimated to be 46 kDa and isoelectric point 7.4. Its Vmax was calculated to be 2.19 U/mg/min, while Km was 0.175 mM. The optimum pH and temperature were 9 and 45 °C, respectively. It was thermostable at 45 °C but thermally inactivated at 60 °C after 50 min. Moreover, its enzymatic activity was enhanced by K+ ions and inhibited by Mg2+ , Cu2+ , Ag+ , Hg2+ , Ni2+ , Fe2+ , Cr2 , Na+ , Ca2+ , and EDTA...
February 16, 2018: International Journal of Biological Macromolecules
Hidetaka Nomura, Kimihiko Sakamoto, Takeru Sugihara, Shuhei Okamoto, Yoichi Aoki, Terumi Tanigawa, Maki Matoda, Kohei Omatsu, Hiroyuki Kanao, Kazuyoshi Kato, Kuniko Utsugi, Yuko Sugiyama, Nobuhiro Takeshima
Pegylated liposomal doxorubicin (PLD) has a good safety profile, but long-term use has been associated with development of squamous cell carcinoma of the tongue and oral cavity (SCCTO) in some patients. The study objective was to estimate the prevalence of oral leukoplakia, a known precursor of SCCTO, in patients with ovarian cancer and long-term PLD use.After approval of the institutional review board, medical record of 114 patients who were treated with PLD at our institution between January 2010 and December 2016 were retrospectively reviewed...
February 2018: Medicine (Baltimore)
Harman S Parhar, Donald W Anderson, Arif S Janjua, J Scott Durham, Eitan Prisman
Objectives There are well-established outcome disparities among different demographic groups with head and neck squamous cell carcinoma (HNSCC). We aimed to investigate the potential contribution of patient choice of nonsurgical treatment to these disparities by estimating the rate of this phenomenon, identifying its predictors, and estimating the effect on cancer-specific survival. Study Design Retrospective nationwide analysis. Settings Surveillance, Epidemiology, and End Results Database (2004-2014). Subjects and Methods Patients with HNSCC, who were recommended for primary surgery, were included...
February 1, 2018: Otolaryngology—Head and Neck Surgery
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