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https://www.readbyqxmd.com/read/28454171/depth-resolution-enhancement-of-terahertz-deconvolution-by-autoregressive-spectral-extrapolation
#1
Junliang Dong, Alexandre Locquet, D S Citrin
This Letter presents a method for enhancing the depth resolution of terahertz deconvolution based on autoregressive (AR) spectral extrapolation. The terahertz frequency components with a high signal-to-noise ratio (SNR) are modeled with an AR process, and the missing frequency components in the regions with low SNRs are extrapolated based on the AR model. In this way, the entire terahertz frequency spectrum of the impulse response function, corresponding to the material structure, is recovered. This method, which is verified numerically and experimentally, is able to provide a "quasi-ideal" impulse response function and, therefore, greatly enhances the depth resolution for characterizing optically thin layers in the terahertz regime...
May 1, 2017: Optics Letters
https://www.readbyqxmd.com/read/28454058/identification-and-characterization-of-process-related-substances-and-degradation-products-in-apremilast-process-optimization-and-degradation-pathway-elucidation
#2
Yuting Lu, Xiaoyue Shen, Taijun Hang, Min Song
This study aims at investigating the separation, identification and characterization of related substances in apremilast by LC-MS hyphenated techniques, as well as the synthesis optimization and the degradation pathways elucidation. Forced degradation studies were conducted under the ICH prescribed stress conditions. The chromatographic separation was achieved on XBridge C18 column (4.6mm×150mm, 3.5μm) using a mobile phase consisting of water adjusted to pH 3.0 with formic acid as solvent A and acetonitrile as solvent B in linear gradient elution program...
April 2, 2017: Journal of Pharmaceutical and Biomedical Analysis
https://www.readbyqxmd.com/read/28454057/application-of-2d-nmr-with-room-temperature-nmr-probes-for-the-assessment-of-the-higher-order-structure-of-filgrastim
#3
Robert G Brinson, Houman Ghasriani, Derek J Hodgson, Kristie M Adams, Ian McEwen, Darón I Freedberg, Kang Chen, David A Keire, Yves Aubin, John P Marino
The higher order structure (HOS) of biotherapeutics is a critical quality attribute that can be evaluated by nuclear magnetic resonance (NMR) spectroscopy at atomic resolution. NMR spectral mapping of HOS can be used to establish HOS consistency of a biologic across manufacturing changes or to compare a biosimilar to an innovator reference product. A previous inter-laboratory study performed using filgrastim drug products demonstrated that two-dimensional (2D)-NMR (1)H(N)-(15)N(H) heteronuclear correlation spectroscopy is a highly robust and precise method for mapping the HOS of biologic drugs at natural abundance using high sensitivity NMR 'cold probes...
April 4, 2017: Journal of Pharmaceutical and Biomedical Analysis
https://www.readbyqxmd.com/read/28453911/validation-of-biomechanical-deformable-image-registration-in-the-abdomen-thorax-and-pelvis-in-a-commercial-radiotherapy-treatment-planning-system
#4
Michael Velec, Joanne L Moseley, Stina Svensson, Björn Hårdemark, David A Jaffray, Kristy K Brock
PURPOSE: The accuracy of deformable image registration tools can vary widely between imaging modalities and specific implementations of the same algorithms. A biomechanical model-based algorithm initially developed in-house at an academic institution was translated into a commercial radiotherapy treatment planning system and validated for multiple imaging modalities and anatomic sites. METHODS: Biomechanical deformable registration (Morfeus) is a geometry driven algorithm based on the finite element method...
April 28, 2017: Medical Physics
https://www.readbyqxmd.com/read/28453814/graphene-specimen-support-technique-for-low-voltage-stem-imaging
#5
Masao Yamashita, Matthew Ryan Leyden, Hidehito Adaniya, Martin Philip Cheung, Teruhisa Hirai, Yabing Qi, Tsumoru Shintake
The scanning transmission electron microscopy (STEM) mode of today's field emission scanning electron microscopes enables sub-nanometer resolution imaging. Graphene is a single-atom thick, electrically conductive material, making it an excellent specimen support for the low voltage STEM imaging of nanometer-sized objects such as viruses. Here we present low voltage STEM images of bacteriophage T4 recorded on highly cleaned graphene films. The results show that ultrathin graphene support films markedly improve image signal at low accelerating voltages...
April 27, 2017: Microscopy
https://www.readbyqxmd.com/read/28453513/genetic-diversity-and-population-structure-of-the-tsetse-fly-glossina-fuscipes-fuscipes-diptera-glossinidae-in-northern-uganda-implications-for-vector-control
#6
Robert Opiro, Norah P Saarman, Richard Echodu, Elizabeth A Opiyo, Kirstin Dion, Alexis Halyard, Augustine W Dunn, Serap Aksoy, Adalgisa Caccone
Uganda is the only country where the chronic and acute forms of human African Trypanosomiasis (HAT) or sleeping sickness both occur and are separated by < 100 km in areas north of Lake Kyoga. In Uganda, Glossina fuscipes fuscipes is the main vector of the Trypanosoma parasites responsible for these diseases as well for the animal African Trypanosomiasis (AAT), or Nagana. We used highly polymorphic microsatellite loci and a mitochondrial DNA (mtDNA) marker to provide fine scale spatial resolution of genetic structure of G...
April 28, 2017: PLoS Neglected Tropical Diseases
https://www.readbyqxmd.com/read/28449245/characterization-of-a-poly-4-vinylpyridine-supported-cupd-bimetallic-catalyst-for-sonogashira-coupling-reactions
#7
Claudio Evangelisti, Antonella Balerna, Rinaldo Psaro, Graziano Fusini, Adriano Carpita, Maurizio Benfatto
CuPd bimetallic Solvated Metal Atoms (SMA) synthesized by metal vapor synthesis (MVS) technique and supported on poly-4-vinylpyridine (PVPy) resin, showed signicantly higher catalytic activity in Sonogashira-type carbon-carbon coupling reactions than the corresponding monometallic Cu and Pd systems as well as their physical mixture. The analysis of the bimetallic catalyst combining high-resolution transmission electron microscopy (HRTEM) and x-ray absorption ne structure (XAFS) spectroscopy revealed the presence of small Pd nanoparticles (dm = 2...
April 27, 2017: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
https://www.readbyqxmd.com/read/28448541/complementary-and-alternative-medicine-cam-use-and-delays-in-presentation-and-diagnosis-of-breast-cancer-patients-in-public-hospitals-in-malaysia
#8
Noor Mastura Mohd Mujar, Maznah Dahlui, Nor Aina Emran, Imisairi Abdul Hadi, Yan Yang Wai, Sarojah Arulanantham, Chea Chan Hooi, Nur Aishah Mohd Taib
Complementary and alternative medicine (CAM) is widely used among the breast cancer patients in Malaysia. Delays in presentation, diagnosis and treatment have been shown to impact the disease prognosis. There is considerable use of CAM amongst breast cancer patients. CAM use has been cited as a cause of delay in diagnosis and treatments in qualitative studies, however there had not been any confirmatory study that confirms its impact on delays. The purpose of this study was to evaluate whether the use of CAM among newly diagnosed breast cancer patients was associated with delays in presentation, diagnosis or treatment of breast cancer...
2017: PloS One
https://www.readbyqxmd.com/read/28448436/role-of-archaeal-hera-protein-in-the-biology-of-the-bacterium-thermus-thermophilus
#9
Alba Blesa, Nieves G Quintans, Ignacio Baquedano, Carlos P Mata, José R Castón, José Berenguer
Intense gene flux between prokaryotes result in high percentage of archaeal genes in the genome of the thermophilic bacteria Thermus spp. Among these archaeal genes a homolog to the Sulfolobus spp. HerA protein appears in all of the Thermus spp. strains so far sequenced (HepA). The role of HepA in Thermus thermophilus HB27 has been analyzed using deletion mutants, and its structure resolved at low resolution by electron microscopy. Recombinant HepA shows DNA-dependent ATPase activity and its structure revealed a double ring, conically-shaped hexamer with an upper diameter of 150 Å and a bottom module of 95 Å...
April 27, 2017: Genes
https://www.readbyqxmd.com/read/28448431/a-type-2-block-component-decomposition-based-2d-aoa-estimation-algorithm-for-an-electromagnetic-vector-sensor-array
#10
Yu-Fei Gao, Guan Gui, Wei Xie, Yan-Bin Zou, Yue Yang, Qun Wan
This paper investigates a two-dimensional angle of arrival (2D AOA) estimation algorithm for the electromagnetic vector sensor (EMVS) array based on Type-2 block component decomposition (BCD) tensor modeling. Such a tensor decomposition method can take full advantage of the multidimensional structural information of electromagnetic signals to accomplish blind estimation for array parameters with higher resolution. However, existing tensor decomposition methods encounter many restrictions in applications of the EMVS array, such as the strict requirement for uniqueness conditions of decomposition, the inability to handle partially-polarized signals, etc...
April 27, 2017: Sensors
https://www.readbyqxmd.com/read/28448153/on-the-thermal-stability-of-metal-nanocrystals-an-investigation-of-the-surface-and-bulk-reconstructions-of-pd-concave-icosahedra
#11
Kyle D Gilroy, Ahmed O Elnabawy, Tung-Han Yang, Luke T Roling, Jane Howe, Manos Mavrikakis, Younan Xia
Despite the remarkable success in controlling the synthesis of metal nanocrystals, it still remains a grand challenge to stabilize and preserve the shapes or internal structures of metastable kinetic products. In this work, we address this issue by systematically investigating the surface and bulk reconstructions experienced by a Pd concave icosahedron when subjected to heating up to 600 (o)C in vacuum. We used in situ high-resolution transmission electron microscopy to identify the equilibration pathways of this far-from-equilibrium structure...
April 27, 2017: Nano Letters
https://www.readbyqxmd.com/read/28448052/an-in-vitro-organ-culture-model-of-the-murine-intervertebral-disc
#12
Jennifer W Liu, Kevin H Lin, Christian Weber, Sameer Bhalla, Sean Kelso, Kaixi Wang, Simon Y Tang
Intervertebral disc (IVD) degeneration is a significant contributor to low back pain. The IVD is a fibrocartilaginous joint that serves to transmit and dampen loads in the spine. The IVD consists of a proteoglycan-rich nucleus pulposus (NP) and a collagen-rich annulus fibrosis (AF) sandwiched by cartilaginous end-plates. Together with the adjacent vertebrae, the vertebrae-IVD structure forms a functional spine unit (FSU). These microstructures contain unique cell types as well as unique extracellular matrices...
April 11, 2017: Journal of Visualized Experiments: JoVE
https://www.readbyqxmd.com/read/28448005/open-source-single-particle-analysis-for-super-resolution-microscopy-with-virusmapper
#13
Robert D M Gray, Jason Mercer, Ricardo Henriques
Super-resolution fluorescence microscopy is currently revolutionizing cell biology research. Its capacity to break the resolution limit of around 300 nm allows for the routine imaging of nanoscale biological complexes and processes. This increase in resolution also means that methods popular in electron microscopy, such as single-particle analysis, can readily be applied to super-resolution fluorescence microscopy. By combining this analytical approach with super-resolution optical imaging, it becomes possible to take advantage of the molecule-specific labeling capacity of fluorescence microscopy to generate structural maps of molecular elements within a metastable structure...
April 9, 2017: Journal of Visualized Experiments: JoVE
https://www.readbyqxmd.com/read/28447597/resonant-and-non-resonant-magnetic-scatterings-with-circularly-polarized-x-rays-magnetic-scattering-factor-and-electron-density-of-gadolinium-iron-garnet
#14
Yo Sasaki, Maki Okube, Satoshi Sasaki
Theoretical and experimental studies on resonant magnetic scattering have been carried out using circularly polarized X-rays. Polarization dependence of the asymmetric ratio between right- and left-handed polarized scattering amplitudes has revealed that resonant and non-resonant magnetic scatterings can be observed simultaneously. In this study, synchrotron X-ray intensity experiments were conducted on Gd iron garnet (GdIG) at the pre-edge of the Fe K absorption edge. The asymmetric ratio between circular polarizations exhibited three peaks due to the resonant magnetic responses of Fe(3+) in the Fe2 (24d) site...
May 1, 2017: Acta Crystallographica. Section A, Foundations and Advances
https://www.readbyqxmd.com/read/28447426/next-generation-sequencing-as-a-tool-for-breakpoint-analysis-in-rearrangements-of-the-globin-gene-clusters
#15
REVIEW
B E Clark, C Shooter, F Smith, D Brawand, S L Thein
INTRODUCTION: Next-generation sequencing (NGS), now embedded within genomic laboratories, is well suited to the detection of small sequence changes but is less well adapt for detecting structural variants (SV), mainly due to the relatively short sequence reads. Of the available target enrichment methods, bait capture or whole-genome sequencing appears better suited to detecting SV as there is less PCR amplification and is therefore more representative of the genome being sequenced. MATERIAL AND METHODS: In 2015, we described the first inversion/deletion causing εγδβ- thalassemia using an NGS approach, with base-pair resolution...
May 2017: International Journal of Laboratory Hematology
https://www.readbyqxmd.com/read/28447085/studying-structure-and-dynamics-of-self-assembled-peptide-nanostructures-using-fluorescence-and-super-resolution-microscopy
#16
Sílvia Pujals, Kai Tao, Adrià Terradellas, Ehud Gazit, Lorenzo Albertazzi
Understanding the formation and properties of self-assembled peptide nanostructures is the basis for the design of new architectures for various applications. Here we show the potential of fluorescence and super resolution imaging to unveil the structural and dynamic features of peptide nanofibers with high spatiotemporal resolution.
April 27, 2017: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/28446777/structural-investigations-on-orotate-phosphoribosyltransferase-from-mycobacterium-tuberculosis-a-key-enzyme-of-the-de-novo-pyrimidine-biosynthesis
#17
Stefano Donini, Davide M Ferraris, Riccardo Miggiano, Alberto Massarotti, Menico Rizzi
The Mycobacterium tuberculosis orotate phosphoribosyltransferase (MtOPRT) catalyses the conversion of α-D-5-phosphoribosyl-1-pyrophosphate (PRPP) and orotate (OA) in pyrophosphate and orotidine 5'-monophosphate (OMP), in presence of Mg(2+). This enzyme is the only responsible for the synthesis of orotidine 5'-monophosphate, a key precursor in the de novo pyrimidine biosynthesis pathway, making MtOPRT an attractive drug target for the development of antitubercular agents. We report the crystal structures of MtOPRT in complex with PRPP (2...
April 26, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28446752/near-atomic-structure-of-japanese-encephalitis-virus-reveals-critical-determinants-of-virulence-and-stability
#18
Xiangxi Wang, Shi-Hua Li, Ling Zhu, Qing-Gong Nian, Shuai Yuan, Qiang Gao, Zhongyu Hu, Qing Ye, Xiao-Feng Li, Dong-Yang Xie, Neil Shaw, Junzhi Wang, Thomas S Walter, Juha T Huiskonen, Elizabeth E Fry, Cheng-Feng Qin, David I Stuart, Zihe Rao
Although several different flaviviruses may cause encephalitis, Japanese encephalitis virus is the most significant, being responsible for thousands of deaths each year in Asia. The structural and molecular basis of this encephalitis is not fully understood. Here, we report the cryo-electron microscopy structure of mature Japanese encephalitis virus at near-atomic resolution, which reveals an unusual "hole" on the surface, surrounded by five encephalitic-specific motifs implicated in receptor binding. Glu138 of E, which is highly conserved in encephalitic flaviviruses, maps onto one of these motifs and is essential for binding to neuroblastoma cells, with the E138K mutation abrogating the neurovirulence and neuroinvasiveness of Japanese encephalitis virus in mice...
April 26, 2017: Nature Communications
https://www.readbyqxmd.com/read/28446042/the-use-of-fibroblasts-for-ameliorating-structural-changes-associated-with-skin-aging
#19
Toshimitsu Itaya, Tatsuo Hirai, Takahisa Hirai, Hideki Numoto, Hideo Takeda, Minoru Ueda
Various causes underlie the structural changes associated with skin aging. To treat these problems, surgical or non-surgical approaches are available. One of the non-surgical approaches- regeneration therapy-has become the focus of research and clinical applications. In an earlier clinical study, we injected fibroblasts into the nasolabial region and lips to counter the structural changes associated with skin aging. Assessments performed 12 months after the first injection showed mostly adequate satisfaction scores...
April 27, 2017: Rejuvenation Research
https://www.readbyqxmd.com/read/28446020/direct-writing-of-microfluidic-footpaths-by-pyro-ehd-printing
#20
Sara Coppola, Giuseppe Nasti, Michele Todino, Federico Olivieri, Veronica Vespini, Pietro Ferraro
A direct writing method for fabricating microfluidic footpaths by pyro-Electrohydrodynamic (EHD) jet printing is reported. Here we propose the use of a nozzle-free 3D printing technique for the fabrication of printed structures that can be embedded in a variety of soft, transparent, flexible and biocompatible polymers, and thus easily integrated into lab-on-chip (LOC) devices. We prove the advantage of the high resolution and flexibility of pyro-EHD printing for the realization of microfluidic channels well below the standard limit in dimension of conventional ink-jet printing technique and simply adaptable to the final user desires in terms of geometry and materials...
April 27, 2017: ACS Applied Materials & Interfaces
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