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Kátia S D Nunes, José H Vallim, Márcia R Assalin, Sonia C N Queiroz, Lourival C Paraíba, Claudio M Jonsson, Felix G R Reyes
The residue depletion of sulfamethazine (SMZ) was evaluated in tilapia (Oreochromis niloticus) after 11 days of administration of medicated feed containing SMZ, at the dose of 422 mg/kg body weight (bw). The determination of SMZ in feed and tilapia fillet was carried out using the QuEChERS approach for sample preparation, and high performance liquid chromatography with diode array detector (HPLC-DAD) and ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-QToF-MS) for quantitation, respectively...
January 9, 2018: Chemosphere
Xiaole Zhang, George Efthimiou, Yan Wang, Meng Huang
Radiation from the deposited radionuclides is indispensable information for environmental impact assessment of nuclear power plants and emergency management during nuclear accidents. Ground shine estimation is related to multiple physical processes, including atmospheric dispersion, deposition, soil and air radiation shielding. It still remains unclear that whether the normally adopted "infinite plane" source assumption for the ground shine calculation is accurate enough, especially for the area with highly heterogeneous deposition distribution near the release point...
January 12, 2018: Journal of Environmental Radioactivity
Jhy-Charm Soo, Eun Gyung Lee, Ryan F LeBouf, Michael L Kashon, William Chisholm, Martin Harper
The objective of this present study was to evaluate the performance of a portable gas chromatograph ─ photoionization detector (GC-PID), under various test conditions to determine if it could be used in occupational settings. A mixture of seven volatile organic compounds (VOCs) - acetone, ethylbenzene, methyl isobutyl ketone, toluene, m-xylene, p-xylene, and o-xylene - was selected because its components are commonly present in paint manufacturing industries. A full-factorial combination of four concentration levels (exposure scenarios) of VOC mixtures, three different temperatures (25˚C, 30˚C, and 35˚C), and three relative humidities (RHs; 25%, 50%, and 75%) was conducted in a full- size controlled environmental chamber...
January 15, 2018: Journal of Occupational and Environmental Hygiene
Noemi Villaseca-González, Virginia Rodríguez Robledo, Lucía Castro-Vázquez, María Victoria Lozano, Manuel J Santander-Ortega, Joaquín González-Fuentes, Pilar Marcos, María Del Mar Arroyo-Jiménez
AIM: We proposed a rapid and high quality method to determine α-tocopherol (α-T) in different biopharmaceutical samples using liquid chromatography-diode array detector on-line ESI-MS/MS. MATERIALS & METHODS: A working standard solution of α-T and internal standard, phenyl-5,7-dimethyl-d6-α-tocopherol, were used for optimization and validation of the method. Levels of α-T in nanoemulsions, serum and plasma samples were evaluated. RESULTS & CONCLUSION: Precision (1% for retention time, 5% for peak area and 3% for relative peak area), linearity range (among 0...
January 15, 2018: Bioanalysis
Rui Liu, Lin Fu, Bruno De Man, Hengyong Yu
Projection and backprojection operations are essential in a variety of image reconstruction and physical correction algorithms in CT. The distance-driven (DD) projection and backprojection are widely used for their highly sequential memory access pattern and low arithmetic cost. However, a typical DD implementation has an inner loop that adjusts the calculation depending on the relative position between voxel and detector cell boundaries. The irregularity of the branch behavior makes it inefficient to be implemented on massively parallel computing devices such as graphics processing units (GPUs)...
December 2017: IEEE Transactions on Computational Imaging
Win Mar
Nuclear Medicine was established in Myanmar in 1963 by Dr Soe Myint and International Atomic Energy expert Dr R. Hochel at Yangon General Hospital. Nuclear medicine diagnostic and therapeutic services started with Probe Scintillation Detector Systems and rectilinear scanner. In the early stage, many Nuclear Medicine specialists from the International Atomic Energy Agency (IAEA) spent some time in Myanmar and made significant contributions to the development of Nuclear Medicine in our country. The department participated in various IAEA technical cooperation projects and regional cooperation projects...
2018: Asia Oceania Journal of Nuclear Medicine & Biology
Hamid Dadkhahi, Benjamin M Marlin
In this paper, we present a new approach to learning cascaded classifiers for use in computing environments that involve networks of heterogeneous and resource-constrained, low-power embedded compute and sensing nodes. We present a generalization of the classical linear detection cascade to the case of tree-structured cascades where different branches of the tree execute on different physical compute nodes in the network. Different nodes have access to different features, as well as access to potentially different computation and energy resources...
August 2017: KDD: Proceedings
Yan Xi, Wenxiang Cong, Daniel Harrison, Ge Wang
In medical X-ray Computed Tomography (CT), the use of two distinct X-ray source spectra (energies) allows dose-reduction and material discrimination relative to that achieved with only one source spectrum. Existing dual-energy CT methods include source kVp-switching, double-layer detection, dual-source gantry, and two-pass scanning. Each method suffers either from strong spectral correlation or patient-motion artifacts. To simultaneously address these problems, we propose to improve CT data acquisition with the Grating Oriented Line-wise Filtration (GOLF) method, a novel X-ray filter that is placed between the source and patient...
December 2017: Sensing and Imaging
Ronghu Mao, Lingling Tian, You Zhang, Lei Ren, Renqi Gao, Fang-Fang Yin, Hong Ge
OBJECTIVE: The objective of this study is to theoretically and experimentally evaluate the dosimetry in the microscopic disease regions surrounding the tumor under stereotactic body radiation therapy of lung cancer. METHODS: For simplicity, the tumor was considered moving along 1 dimension with a periodic function. The probability distribution function of the tumor position was generated according to the motion pattern and was used to estimate the delivered dose in the microscopic disease region...
December 2017: Technology in Cancer Research & Treatment
Wenwen Lin, Constantinos C Stoumpos, Oleg Y Kontsevoi, Zhifu Liu, Yihui He, Sanjib Das, Yadong Xu, Kyle M McCall, Bruce W Wessels, Mercouri G Kanatzidis
Cu2I2Se6 is a new wide-bandgap semiconductor with high stability and great potential towards hard radiation and photon detection. Cu2I2Se6 crystallizes in the rhombohedral R3 ̅m space group with a density of d = 5.287 g·cm-3 and a wide bandgap Eg of 1.95 eV. First-principles electronic band structure calculations at the density functional theory level indicate an indirect bandgap and a low electron effective mass me* of 0.32. The congruently melting compound was grown in centimeter-size Cu2I2Se6 single crystals using a vertical Bridgman method...
January 14, 2018: Journal of the American Chemical Society
Ji Hyun Park, Sungim Whang, Hyun Young Lee, Cheol-Min Lee, Dae Ryong Kang
Objectives: Radon, the primary constituent of natural radiation, is the second leading environmental cause of lung cancer after smoking. To confirm a relationship between indoor radon exposure and lung cancer, estimating cumulative levels of exposure to indoor radon for an individual or population is necessary. This study sought to develop a model for estimate indoor radon concentrations in Korea. Especially, our model and method may have wider application to other residences, not to specific site, and can be used in situations where actual measurements for input variables are lacking...
January 8, 2018: Environmental Health and Toxicology
Vania Sáez, Camila Gayoso, Sebastián Riquelme, Julie Pérez, Carola Vergara, Claudia Mardones, Dietrich von Baer
Grape canes, the residues from the annual pruning of vines, contain high levels of inducible (E)-resveratrol and also oligomeric stilbenoids and proanthocyanidins. These two families of phenolic compounds are bioactive, but to quantify them in a single chromatographic run using only ultraviolet detection is a difficult task. To overcome this limitation, a chromatographic method was developed using a core shell column for separation, an ultraviolet-visible diode array detector (DAD) and a fluorescence (FL) detector connected in series for quantification, with an electrospray ionization interface (ESI) and a triple quadrupole mass spectrometric detector (MS/MS) added for identification of the analytes...
December 29, 2017: Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences
Mohamed Yasreen Mohamed Ali, Marlia M Hanafiah, Md Firoz Khan
This study aimed to measure the equilibrium equivalent radon (EECRn) concentration in an old building (Building-1) and a new building (Building-2) with mechanical ventilation and a natural ventilation system, respectively. Both buildings were located at the campus of University Kebangsaan Malaysia. The concentration of indoor radon was measured at 25 sampling stations using a radon detector model DOSEman PRO. The sampling was conducted for 8 h to represent daily working hours. A correlation of the radon concentration was made with the annual inhalation dose of the occupants at the indoor stations...
January 11, 2018: Science of the Total Environment
F Tavakkoli, M Zahedifar, E Sadeghi
LaF3: Ag nanoparticles (NPs) were synthesized by the co-precipitation method. The produced NPs were characterized by X-ray diffraction (XRD) pattern, scanning electron microscope (SEM), dynamic light scattering (DLS) and Fourier transform infrared spectroscopy (FTIR). The emission spectrum of LaF3:Ag NPs is mostly overlapped with the absorption band of protoporphyrin IX (PpIX) and their conjugation was confirmed by studying fluorescence resonance energy transfer (FRET) from LaF3:Ag donor to protoporphyrin IX acceptor...
January 10, 2018: Photodiagnosis and Photodynamic Therapy
A Villière, S Le Roy, C Fillonneau, C Prost
Despite continuous advances in analytical and physiological knowledge, the comprehension of an aroma is still a challenge. Gas chromatography coupled to olfactometry (GC-O) is an efficient method to identify and estimate individual potential of odorants, but there is a gap between this individual characterization and the effective contribution of compounds in the mixture, which is due to complex chemical and perceptual interactions. Therefore, recombination and omission experiments are often performed to achieve an understanding of food aromas...
December 24, 2017: Journal of Chromatography. A
Saeed Reza Kheradpisheh, Mohammad Ganjtabesh, Simon J Thorpe, Timothée Masquelier
Previous studies have shown that spike-timing-dependent plasticity (STDP) can be used in spiking neural networks (SNN) to extract visual features of low or intermediate complexity in an unsupervised manner. These studies, however, used relatively shallow architectures, and only one layer was trainable. Another line of research has demonstrated - using rate-based neural networks trained with back-propagation - that having many layers increases the recognition robustness, an approach known as deep learning. We thus designed a deep SNN, comprising several convolutional (trainable with STDP) and pooling layers...
December 23, 2017: Neural Networks: the Official Journal of the International Neural Network Society
Yao-Kun Xu, Shi-Hai Sun, Wei-Tao Liu, Guang-Zhao Tang, Ji-Ying Liu, Ping-Xing Chen
Measurement of fast signal is getting more and more important in many fields. In this paper, we propose to detect a temporal signal based on the idea of computational ghost imaging (GI), which can greatly reduce requirements on bandwidth of detectors. In experiments, we implement retrieving of a temporal signal with time scale of 50ns using a detector of 1kHz bandwidth, which is much lower than the requirement on bandwidth of detector according to information theory. The performance of our technique are also investigated under different detection bandwidths...
January 8, 2018: Optics Express
Enzheng Zhang, Benyong Chen, Hao Zheng, Liping Yan, Xueying Teng
A laser heterodyne interferometer with rotational error compensation is proposed for precision displacement measurement. In this interferometer, the rotational error of the measured object is obtained by using an angle detecting unit which is composed of a semi-reflective film, a polarizing beam splitter, a quarter-wave plate, a convex lens and a two-dimensional position sensitive detector. And the obtained rotational angle is used for compensating its influence on displacement measurement result. The optical configuration of the proposed interferometer is designed, and the mathematical model for displacement measurement with rotational error compensation is established...
January 8, 2018: Optics Express
Xiaoliang He, Cheng Liu, Jianqiang Zhu
An optical setup and corresponding reconstruction algorithm are proposed to realize single-shot Fourier ptychography (FP). Multiple angle-varied object waves are generated by placing a Dammann grating at a certain distance behind the object, and the generated image array of low resolution corresponding to different diffraction orders formed on the detector plane is recorded simultaneously in a single exposure. The amplitude, as well as the phase information of the object, can be properly reconstructed with a common FP algorithm from the recorded image array...
January 15, 2018: Optics Letters
Qun Yuan, Zhishan Gao, Yimeng Dou, Yanxia Yao, Lu Chen
The ideal mapping geometry in a Fizeau interferometer is to map equal height increments on a flat object and equal angle increments on a spherical surface to equal heights on the detector. So the initial intent of the optical design of Fizeau transmission spheres (TSs) is to provide R-θ mapping geometry for equal angle increments. The corresponding unequal heights mapping will introduce retrace error as coma when linear carrier fringes exist. On the contrary, equal heights mapping with R-sin θ mapping geometry will avoid linear carrier fringes induced coma error...
January 10, 2018: Applied Optics
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