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https://www.readbyqxmd.com/read/29150942/a-novel-epididymal-quiescence-factor-inhibits-sperm-motility-by-modulating-nos-activity-and-intracellular-no-cgmp-pathway
#1
Prasanta Ghosh, Sandipan Mukherjee, Arpita Bhoumik, Sandhya Rekha Dungdung
Mature and potentially motile spermatozoa stored in cauda epididymis in an inactive state for approximately 30 days; however during ejaculation they regain motility. To understand the actual molecular mechanism of the sperm quiescence during caudal stay, a proteinaceous quiescence factor (QF) has been purified from caprine epididymal plasma to apparent homogeneity. In the present study complete purification, detailed characterization as well as mechanistic pathway of QF has been described. QF was purified to 215 fold with 45% activity recovery...
November 18, 2017: Journal of Cellular Physiology
https://www.readbyqxmd.com/read/29150807/single-cell-versus-large-population-analysis-cell-variability-in-elemental-intracellular-concentration-and-distribution
#2
Emil Malucelli, Alessandra Procopio, Michela Fratini, Alessandra Gianoncelli, Andrea Notargiacomo, Lucia Merolle, Azzurra Sargenti, Sara Castiglioni, Concettina Cappadone, Giovanna Farruggia, Marco Lombardo, Stefano Lagomarsino, Jeanette A Maier, Stefano Iotti
The quantification of elemental concentration in cells is usually performed by analytical assays on large populations missing peculiar but important rare cells. The present article aims at comparing the elemental quantification in single cells and cell population in three different cell types using a new approach for single cells elemental analysis performed at sub-micrometer scale combining X-ray fluorescence microscopy and atomic force microscopy. The attention is focused on the light element Mg, exploiting the opportunity to compare the single cell quantification to the cell population analysis carried out by a highly Mg-selective fluorescent chemosensor...
November 17, 2017: Analytical and Bioanalytical Chemistry
https://www.readbyqxmd.com/read/29150709/simultaneous-detection-of-nadph-consumption-and-h2o2-production-using-the-ampliflu%C3%A2-red-assay-for-screening-of-p450-activities-and-uncoupling
#3
Lisa K Morlock, Dominique Böttcher, Uwe T Bornscheuer
Cytochrome P450s belong to a large and diverse group of heme-containing enzymes. These monooxygenases catalyze the incorporation of a single atom of molecular oxygen into their substrate. In contrast to most other enzymes, the activity of P450 enzymes is not only dependent on substrate and cofactor availability and reaction conditions, but also depends on the coupling efficiency of the catalytic cycle itself. Through the electron transfer from NAD(P)H to the heme-center of the P450, the enzyme becomes activated and binds oxygen...
November 17, 2017: Applied Microbiology and Biotechnology
https://www.readbyqxmd.com/read/29150657/specific-heat-electrical-resistivity-and-electronic-band-structure-properties-of-noncentrosymmetric-th7fe3-superconductor
#4
V H Tran, M Sahakyan
Noncentrosymmetric superconductor Th7Fe3 has been investigated by means of specific heat, electrical resisitivity measurements and electronic properties calculations. Sudden drop in the resistivity at 2.05 ± 0.15 K and specific heat jump at 1.98 ± 0.02 K are observed, rendering the superconducting transition. A model of two BCS-type gaps appears to describe the zero-magnetic-field specific heat better than those based on the isotropic BCS theory or anisotropic functions. A positive curvature of the upper critical field H c2(T c) and nonlinear field dependence of the Sommerfeld coefficient at 0...
November 17, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29150653/a-theoretical-quest-for-high-temperature-superconductivity-on-the-example-of-low-dimensional-carbon-structures
#5
C H Wong, R Lortz, E A Buntov, R E Kasimova, A F Zatsepin
High temperature superconductivity does not necessarily require correlated electron systems with complex competing or coexisting orders. Instead, it may be achieved in a phonon-mediated classical superconductor having a high Debye temperature and large electronic density of states at the Fermi level in a material with light atoms and strong covalent bonds. Quasi-1D conductors seem promising due to the Van Hove singularities in their electronic density of states. In this sense, quasi-1D carbon structures are good candidates...
November 17, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29150649/non-empirical-atomistic-dipole-interaction-model-for-quantum-plasmon-simulation-of-nanoparticles
#6
Jaechang Lim, Sungwoo Kang, Jaewook Kim, Woo Youn Kim, Seol Ryu
Plasmonic nanoparticles in the quantum regime exhibit characteristic optical properties that cannot be described by classical theories. Time-dependent density functional theory (TDDFT) is rising as a versatile tool for study on such systems, but its application has been limited to very small clusters due to rapidly growing computational costs. We propose an atomistic dipole-interaction-model for quantum plasmon simulations as a practical alternative. Namely the atomic dipole approximation represents induced dipoles with atomic polarizabilities obtained from TDDFT without empirical parameters...
November 17, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29150627/high-efficiency-backward-four-wave-mixing-by-quantum-interference
#7
Zi-Yu Liu, Jian-Ting Xiao, Jia-Kang Lin, Jun-Jie Wu, Jz-Yuan Juo, Chin-Yao Cheng, Yong-Fan Chen
Electromagnetically-induced-transparency-based four-wave mixing (FWM) in a resonant four-level double-Λ system has a maximum conversion efficiency (CE) of 25% due to spontaneous emission. Herein, we demonstrate that spontaneous emission can be considerably suppressed by arranging the applied laser beams in a backward configuration. With the backward double-Λ FWM scheme, we observe a CE of 63% in cold rubidium atoms with an optical depth (OD) of 48. To the best of our knowledge, this is the first observation of a CE exceeding the conversion limit in resonant FWM processes...
November 17, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29150617/carbon-contamination-during-ion-irradiation-accurate-detection-and-characterization-of-its-effect-on-microstructure-of-ferritic-martensitic-steels
#8
Jing Wang, Mychailo B Toloczko, Karen Kruska, Daniel K Schreiber, Danny J Edwards, Zihua Zhu, Jiandong Zhang
Accelerator-based ion beam irradiation techniques have been used to study radiation effects in materials for decades. Although carbon contamination induced by ion beams in target materials is a well-known issue in some material systems, it has not been fully characterized nor quantified for studies in ferritic/martensitic (F/M) steels that are candidate materials for applications such as core structural components in advanced nuclear reactors. It is an especially important issue for this class of material because of the strong effect of carbon level on precipitate formation...
November 17, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29150609/atomic-resolution-snapshot-of-leishmania-ribosome-inhibition-by-the-aminoglycoside-paromomycin
#9
Moran Shalev-Benami, Yan Zhang, Haim Rozenberg, Yuko Nobe, Masato Taoka, Donna Matzov, Ella Zimmerman, Anat Bashan, Toshiaki Isobe, Charles L Jaffe, Ada Yonath, Georgios Skiniotis
Leishmania is a single-celled eukaryotic parasite afflicting millions of humans worldwide, with current therapies limited to a poor selection of drugs that mostly target elements in the parasite's cell envelope. Here we determined the atomic resolution electron cryo-microscopy (cryo-EM) structure of the Leishmania ribosome in complex with paromomycin (PAR), a highly potent compound recently approved for treatment of the fatal visceral leishmaniasis (VL). The structure reveals the mechanism by which the drug induces its deleterious effects on the parasite...
November 17, 2017: Nature Communications
https://www.readbyqxmd.com/read/29150558/branched-pectic-galactan-in-phloem-sieve-element-cell-walls-implications-for-cell-mechanics
#10
Thomas A Torode, Rachel E O'Neill, Susan E Marcus, Valerie Cornuault, Sara Pose-Albacete, Rebecca P Lauder, Stjepan Kresimir Kracun, Maja Gro Rydahl, Mathias C F Andersen, William George Tycho Willats, Siobhan Ariel Braybrook, Belinda J Townsend, Mads H Clausen, J Paul Knox
A major question in plant biology concerns the specification and functional differentiation of cell types. This is in the context of constraints imposed by networks of cell walls that both adhere cells and contribute to the form and function of developing organs. Here, we report the identification of a glycan epitope that is specific to phloem sieve element cell walls in several systems. A monoclonal antibody, designated LM26, binds to the cell wall of phloem sieve elements in stems of Arabidopsis thaliana, Miscanthus x giganteus and notably sugar beet (Beta vulgaris) roots where phloem identification is an important factor for the study of phloem unloading of sucrose...
November 17, 2017: Plant Physiology
https://www.readbyqxmd.com/read/29150378/enhanced-antibacterial-effects-of-green-synthesized-zno-nps-using-aristolochia-indica-against-multi-drug-resistant-bacterial-pathogens-from-diabetic-foot-ulcer
#11
Katherin Steffy, G Shanthi, Anson S Maroky, S Selvakumar
BACKGROUND: Increased incidence of Multi-drug resistance in microorganisms has become the greatest challenge in the treatment of Diabetic Foot Ulcer (DFU) and urges the need of a new antimicrobial agent. In this study, we determined the bactericidal effects of ZnO nanoparticles (ZnO NPs) green synthesized from Aristolochia indica against Multi-drug Resistant Organisms (MDROs) isolated from pus samples of DFU patients attending in a tertiary care hospital in South India. METHODS: ZnO NPs were characterized by UV-vis-DRS spectroscopy, Atomic Force Microscopy (AFM), Transmission Electron Microscopy (TEM) and for its zeta potential value...
November 14, 2017: Journal of Infection and Public Health
https://www.readbyqxmd.com/read/29150015/the-flotation-and-adsorption-of-mixed-collectors-on-oxide-and-silicate-minerals
#12
REVIEW
Longhua Xu, Jia Tian, Houqin Wu, Zhongyuan Lu, Wei Sun, Yuehua Hu
The analysis of flotation and adsorption of mixed collectors on oxide and silicate minerals is of great importance for both industrial applications and theoretical research. Over the past years, significant progress has been achieved in understanding the adsorption of single collectors in micelles as well as at interfaces. By contrast, the self-assembly of mixed collectors at liquid/air and solid/liquid interfaces remains a developing area as a result of the complexity of the mixed systems involved and the limited availability of suitable analytical techniques...
November 11, 2017: Advances in Colloid and Interface Science
https://www.readbyqxmd.com/read/29149889/electronic-cigarette-vapor-alters-the-lateral-structure-but-not-tensiometric-properties-of-calf-lung-surfactant
#13
Rebecca J Przybyla, Jason Wright, Rajan Parthiban, Saeed Nazemidashtarjandi, Savas Kaya, Amir M Farnoud
BACKGROUND: Despite their growing popularity, the potential respiratory toxicity of electronic cigarettes (e-cigarettes) remains largely unknown. One potential aspect of e-cigarette toxicity is the effect of e-cigarette vapor on lung surfactant function. Lung surfactant is a mixture of lipids and proteins that lines the alveolar region. The surfactant layer reduces the surface tension of the alveolar fluid, thereby playing a crucial role in lung stability. Due to their small size, particulates in e-cigarette vapor can penetrate the deep lungs and come into contact with the lung surfactant...
November 17, 2017: Respiratory Research
https://www.readbyqxmd.com/read/29149812/architectures-and-mechanical-properties-of-drugs-and-complexes-of-surface-active-compounds-at-air-water-and-oil-water-interfaces
#14
Dipak K Sarker
BACKGROUND: Drugs can represents a multitude of compounds from proteins and peptides, such as growth hormones and insulin and on to simple organic molecules such as flurbiprofen, ibuprofen and lidocaine. Given the chemical nature of these compounds two features are always present. A portion or portions of the molecule that has little affinity for apolar surfaces and media and the opposite a series of part or one large part that has considerable affinity for hydrophilic, polar or charged media and surfaces...
November 17, 2017: Current Drug Discovery Technologies
https://www.readbyqxmd.com/read/29149699/tetrahymena-cilia-cap-is-built-in-a-multi-step-process-a-study-by-atomic-force-microscopy
#15
Cecília Seixas, João Gonçalves, Luís Viseu Melo, Helena Soares
Cilia are complex and dynamic organelles that have motility and sensory functions. Defects in cilia biogenesis and function are at the origin of human ciliopathies. In motile cilia, a basal body organizes the axoneme composed of nine microtubule doublets surrounding a central pair of singlet microtubules. The distal ends of axonemal microtubules are attached to the membrane by microtubule-capping structures. Little is known about the early steps of cilium assembly. Although cilia grow and resorb from their distal tips, it remains poorly understood where and when the components of the caps are first assembled...
October 20, 2017: Protist
https://www.readbyqxmd.com/read/29149619/association-of-snps-in-genes-encoding-zinc-transporters-on-blood-zinc-levels-in-humans
#16
Junko Fujihara, Toshihiro Yasuda, Kaori Kimura-Kataoka, Yoshikazu Takinami, Masataka Nagao, Haruo Takeshita
Zinc homeostasis in cells depends on zinc transporters, which are divided into 2 families: ZnT (SLC30A) and ZIP (SLC39A). In this study, we examined the effect of 20 single nucleotide polymorphisms (SNPs) in 10 genes encoding zinc transporters on blood zinc concentration in Japanese subjects (n = 102). Blood zinc levels were determined by microwave plasma-atomic emission spectrometry, and SNPs were analyzed by polymerase chain reaction followed by restriction fragment length polymorphism analysis. Among the 20 SNPs examined, 3 SNPs (SLC30A3 rs11126936, SLC39A8 rs233804, and SLC39A14 rs4872479) were significantly associated with blood zinc concentration...
November 9, 2017: Legal Medicine
https://www.readbyqxmd.com/read/29149568/individual-atomic-imaging-of-multiple-dopant-sites-in-as-doped-si-using-spectro-photoelectron-holography
#17
Kazuo Tsutsui, Tomohiro Matsushita, Kotaro Natori, Takayuki Muro, Yoshitada Morikawa, Takuya Hoshii, Kuniyuki Kakushima, Hitoshi Wakabayashi, Kouichi Hayashi, Fumihiko Matsui, Toyohiko Kinoshita
The atomic scale characterization of dopant atoms in semiconductor devices to establish correlations with the electrical activation of these atoms is the essential to the advancement of contemporary semiconductor process technology. Spectro-photoelectron holography combined with first-principles simulations can determine the local three-dimensional atomic structures of dopant elements, which in turn affect their electronic states. In the work reported herein, this technique was used to examine arsenic (As) atoms doped into a silicon (Si) crystal...
November 17, 2017: Nano Letters
https://www.readbyqxmd.com/read/29149556/evaluating-force-field-london-dispersion-coefficients-using-the-exchange-hole-dipole-moment-model
#18
Mohamad Mohebifar, Erin R Johnson, Christopher N Rowley
London dispersion interactions play an integral role in materials science and biophysics. Force fields for atomistic molecular simulations typically represent dispersion interactions by the 12-6 Lennard-Jones potential, using empirically-determined parameters. These parameters are generally underdetermined and there is no straightforward way to test if they are physically realistic. Alternatively, the exchange-hole dipole moment (XDM) model from density-functional theory predicts atomic and molecular London dispersion coefficients from first principles, providing an innovative strategy to validate the dispersion terms of molecular-mechanical force fields...
November 17, 2017: Journal of Chemical Theory and Computation
https://www.readbyqxmd.com/read/29149535/a-valence-delocalised-osmium-dimer-capable-of-dinitrogen-photocleavage-ab-initio-insights-into-its-electronic-structure
#19
Vera Krewald, Leticia Gonzalez
The search for molecular catalysts that efficiently activate or cleave the dinitrogen molecule is ongoing. While many thermal dinitrogen cleavage catalysts are known, the photochemical activation of N₂ has received considerably less attention. In this paper, we present the first computational study of the osmium dimer [Os(II,III)₂(µ-N₂)(NH₃)₁₀]5+, which was shown to be capable of dinitrogen photocleavage. Despite its deceptively simple geometry, it has a complex electronic structure with a valence-delocalized and electronically degenerate ground state...
November 17, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/29149444/morphology-molecular-structure-and-stable-carbon-isotopic-composition-of-black-carbon-bc-in-urban-topsoils
#20
Yutong Zong, Qing Xiao, Shenggao Lu
Urban soils contain significant amounts of black carbon (BC) from biomass and fossil fuel combustion and regard to be a pool of BC. BC in urban soils has multiple effects on environmental processes in urban system, such as global climate change, air quality, and public health. Urban topsoil samples (0-10 cm) were collected from Anshan, Liaoning Province, northeast China, which is one of the most important old steel industrial bases in China. The BC in urban topsoils was extracted using the density method. Their chemical composition, morphology, molecular structure, and stable carbon isotopic composition were examined using elemental analysis, scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), X-ray diffraction (XRD), and stable carbon isotope (δ(13)C)...
November 17, 2017: Environmental Science and Pollution Research International
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