bluuebunny/crossref_metadata_2025_split huggingface dataset:
The mechanism of NDM-1-catalyzed carbapenem hydrolysis is distinct from that of penicillin or cephalosporin hydrolysis
Authors: Feng Han , Liu Xuehui , Wang Sheng , Fleming Joy , Wang Da-Cheng , Liu Wei 
Published: December 2017

AbstractNew Delhi metallo-β-lactamases (NDMs), the recent additions to metallo-β-lactamases (MBLs), pose a serious public health threat due to its highly efficient hydrolysis of β-lactam antibiotics and rapid worldwide dissemination. The MBL-hydrolyzing mechanism for carbapenems is less studied than that of penicillins and cephalosporins. Here, we report crystal structures of NDM-1 in complex with hydrolyzed imipenem and meropenem, at resolutions of 1.80–2.32 Å, together with NMR spectra monitoring meropenem hydrolysis. Three enzyme-intermediate/product derivatives, EI1, EI2, and EP, are trapped in these crystals. Our structural data reveal double-bond tautomerization from Δ2 to Δ1, absence of a bridging water molecule and an exclusive β-diastereomeric product, all suggesting that the hydrolytic intermediates are protonated by a bulky water molecule incoming from the β-face. These results strongly suggest a distinct mechanism of NDM-1-catalyzed carbapenem hydrolysis from that of penicillin or cephalosporin hydrolysis, which may provide a novel rationale for design of mechanism-based inhibitors.
Hidden genetic variation shapes the structure of functional elements in Drosophila
Authors: Chakraborty Mahul , VanKuren Nicholas W. , Zhao Roy , Zhang Xinwen , Kalsow Shannon , Emerson J. J. 
Published: December 2017

AbstractMutations that add, subtract, rearrange, or otherwise refashion genome structure often affect phenotypes, although the fragmented nature of most contemporary assemblies obscures them. To discover such mutations, we assembled the first new reference-quality genome ofDrosophila melanogastersince its initial sequencing. By comparing this new genome to the existingD. melanogasterassembly, we created a structural variant map of unprecedented resolution and identified extensive genetic variation that has remained hidden until now. Many of these variants constitute candidates underlying phenotypic variation, including tandem duplications and a transposable element insertion that amplifies the expression of detoxification-related genes associated with nicotine resistance. The abundance of important genetic variation that still evades discovery highlights how crucial high-quality reference genomes are to deciphering phenotypes.
Prefabrication of a functional bone graft with a pedicled periosteal flap as an in vivo bioreactor
Authors: Huang Ru-Lin , Tremp Mathias , Ho Chia-Kang , Sun Yangbai , Liu Kai , Li Qingfeng 
Published: December 2017

AbstractThein vivobioreactor principle, which focuses on using the body as a living bioreactor to cultivate stem cells, bioscaffolds, and growth factors and leveraging the body’s self-regenerative capacity to regenerate new tissue, has been considered a potential approach for bone defect reconstruction. The histological characteristics of the periosteum allow it to possess a remarkable capacity to induce bone growth and remodeling, making it suitable as anin vivobioreactor strategy for bone graft prefabrication. The present study was designed to prefabricate vascularized bone grafts using pedicled periosteal flaps and decellularized bone matrix (DBM) scaffolds in a rabbit model. The muscular pouches created in the femoral muscle were acted as a control. Our histological results revealed that both the periosteal flap group and muscular pouch group induced bone tissue formation on the DBM surface at both 8 and 16 weeks postoperatively. However, micro-computed tomography (microCT) scanning, biomechanical, and histomorphometric findings indicated that bone grafts from the periosteal flap group showed larger bone mass, faster bone formation rates, higher vascular density, and stronger biomechanical properties than in the muscular pouch group. We suggest that using the pedicled periosteal flap as anin vivobioreactor is a promising approach for functional bone graft prefabrication.
Disentangling the influence of climate, soil and belowground microbes on local species richness in a dryland ecosystem of Northwest China
Authors: Wang Jianming , Long Ting , Zhong Yueming , Li Jingwen , Zhang Tianhan , Feng Yiming , Lu Qi 
Published: December 2017

AbstractXinjiang Uygur Autonomous Region (XUAR) covers one of the largest drylands in the world, while the relative effects of different environmental factors on plant diversity are poorly understood. We sampled 66 sites in a typical dryland of XUAR, which covers more than 450,000 km2, to evaluate the relative influences of different factors on the patterns of local plant species richness (LPSR). We found that overall and herbaceous LPSR were positively correlated with water availability, soil nutrients but negatively correlated with energy availability, while the shrub LPSR showed the opposite response. Climate, soil attributes together explained 53.2% and 59.2% of the variance in overall and herbaceous LPSR, respectively; revealing that LPSR patterns were shaped by abiotic and underground biotic factors together. Only 31.5% of the variance in the shrub LPSR was explained by soil attributes, indicating that shrub LPSR was mainly limited by non-climatic factors. There findings provide robust evidence that relative contribution of climate and soil attributes differ markedly depending on the plant functional group. Furthermore, we found the different relationship between microbes and plant diversity, indicating that the linkages between soil microbial diversity and plant diversity may vary across functional groups of microbes and plant. These findings provide robust evidence that the relative roles of climate, soil and microbes differ markedly depending on the plant functional group. Microbial richness showed a significantly pure influence on the LPSR of all groups, suggesting that microbes play a non-negligible role in regulating plant diversity in dryland ecosystems.
Precipitation variability increases in a warmer climate
Authors: Pendergrass Angeline G. , Knutti Reto , Lehner Flavio , Deser Clara , Sanderson Benjamin M. 
Published: December 2017

AbstractUnderstanding changes in precipitation variability is essential for a complete explanation of the hydrologic cycle’s response to warming and its impacts. While changes in mean and extreme precipitation have been studied intensively, precipitation variability has received less attention, despite its theoretical and practical importance. Here, we show that precipitation variability in most climate models increases over a majority of global land area in response to warming (66% of land has a robust increase in variability of seasonal-mean precipitation). Comparing recent decades to RCP8.5 projections for the end of the 21st century, we find that in the global, multi-model mean, precipitation variability increases 3–4% K−1 globally, 4–5% K−1 over land and 2–4% K−1 over ocean, and is remarkably robust on a range of timescales from daily to decadal. Precipitation variability increases by at least as much as mean precipitation and less than moisture and extreme precipitation for most models, regions, and timescales. We interpret this as being related to an increase in moisture which is partially mitigated by weakening circulation. We show that changes in observed daily variability in station data are consistent with increased variability.
Integration of miRNA and gene expression profiles suggest a role for miRNAs in the pathobiological processes of acute Trypanosoma cruzi infection
Authors: Ferreira Ludmila Rodrigues Pinto , Ferreira Frederico Moraes , Laugier Laurie , Cabantous Sandrine , Navarro Isabela Cunha , da Silva Cândido Darlan , Rigaud Vagner Carvalho , Real Juliana Monte , Pereira Glaucia Vilar , Pereira Isabela Resende , Ruivo Leonardo , Pandey Ramendra Pati , Savoia Marilda , Kalil Jorge , Lannes-Vieira Joseli , Nakaya Helder , Chevillard Christophe , Cunha-Neto Edecio 
Published: December 2017

AbstractChagas disease, caused by the parasite Trypanosoma cruzi, is endemic in Latin America. Its acute phase is associated with high parasitism, myocarditis and profound myocardial gene expression changes. A chronic phase ensues where 30% develop severe heart lesions. Mouse models of T. cruzi infection have been used to study heart damage in Chagas disease. The aim of this study was to provide an interactome between miRNAs and their targetome in Chagas heart disease by integrating gene and microRNA expression profiling data from hearts of T. cruzi infected mice. Gene expression profiling revealed enrichment in biological processes and pathways associated with immune response and metabolism. Pathways, functional and upstream regulator analysis of the intersections between predicted targets of differentially expressed microRNAs and differentially expressed mRNAs revealed enrichment in biological processes and pathways such as IFNγ, TNFα, NF-kB signaling signatures, CTL-mediated apoptosis, mitochondrial dysfunction, and Nrf2-modulated antioxidative responses. We also observed enrichment in other key heart disease-related processes like myocarditis, fibrosis, hypertrophy and arrhythmia. Our correlation study suggests that miRNAs may be implicated in the pathophysiological processes taking place the hearts of acutely T. cruzi-infected mice.
Microbial stress mediated intercellular nanotubes in an anaerobic microbial consortium digesting cellulose
Authors: John Martina , Trzcinski Antoine Prandota , Zhou Yan , Ng Wun Jern 
Published: December 2017

AbstractThe anaerobic digestion process is a multi - step reaction dependent on concerted activities such as exchange of metabolites among physiologically different microbial communities. This study investigated the impact of iron oxide nanoparticles on the anaerobic sludge microbiota. It was shown there were three distinct microbial phases following addition of the nanoparticles: microbial stress and cell death of approximately one log order of magnitude, followed by microbial rewiring, and recovery. Furthermore, it was noted that cellular stress led to the establishment of intercellular nanotubes within the microbial biomass. Intercellular nanotube - mediated communication among genetically engineered microorganisms and ad hoc assembled co - cultures have been previously reported. This study presents evidence of intercellular nanotube formation within an environmental sample – i.e., anaerobic sludge microbiota subjected to stress. Our observations suggested a mode of microbial communication in the anaerobic digestion process not previously explored and which may have implications on bioreactor design and microbial functions.
Application of Fourier transform infrared spectroscopy with chemometrics on postmortem interval estimation based on pericardial fluids
Authors: Zhang Ji , Li Bing , Wang Qi , Wei Xin , Feng Weibo , Chen Yijiu , Huang Ping , Wang Zhenyuan 
Published: December 2017

AbstractPostmortem interval (PMI) evaluation remains a challenge in the forensic community due to the lack of efficient methods. Studies have focused on chemical analysis of biofluids for PMI estimation; however, no reports using spectroscopic methods in pericardial fluid (PF) are available. In this study, Fourier transform infrared (FTIR) spectroscopy with attenuated total reflectance (ATR) accessory was applied to collect comprehensive biochemical information from rabbit PF at different PMIs. The PMI-dependent spectral signature was determined by two-dimensional (2D) correlation analysis. The partial least square (PLS) and nu-support vector machine (nu-SVM) models were then established based on the acquired spectral dataset. Spectral variables associated with amide I, amide II, COO−, C-H bending, and C-O or C-OH vibrations arising from proteins, polypeptides, amino acids and carbohydrates, respectively, were susceptible to PMI in 2D correlation analysis. Moreover, the nu-SVM model appeared to achieve a more satisfactory prediction than the PLS model in calibration; the reliability of both models was determined in an external validation set. The study shows the possibility of application of ATR-FTIR methods in postmortem interval estimation using PF samples.
Fast polarization mechanisms in the uniaxial tungsten-bronze relaxor strontium barium niobate SBN-81
Authors: Buixaderas E. , Kadlec C. , Kempa M. , Bovtun V. , Savinov M. , Bednyakov P. , Hlinka J. , Dec J. 
Published: December 2017

AbstractThe high-frequency dielectric response of the uniaxial strontium barium niobate crystals with 81% of Sr has been studied from 1 kHz to 30 THz along the polarcaxis by means of several techniques (far infrared, time domain terahertz, high-frequency and low-frequency dielectric spectroscopies) in a wide temperature interval 20–600 K. Relaxor properties were observed in the complex dielectric response and four main excitations were ascertained below the phonon frequencies. These fast polarization mechanisms take place at THz, GHz and MHz ranges and show different temperature evolution. The central mode excitation in the THz range, related to anharmonic dynamics of cations, slightly softens from high temperatures and then hardens belowT ~ 400 K. Below the phase transition (atT~ 330 K) an additional microwave excitation appears near 10 GHz related to micro domain wall oscillations. The strongest relaxation appears in the GHz range and slows down on cooling according to the Arrhenius law. Finally, another relaxation, present in the MHz range at high temperatures, also slows down on cooling at least to the kHz range. These two relaxations are due to polar fluctuations and nanodomains dynamics. Altogether, the four excitations explain the dielectric permittivity maximum in the kHz range.
Tunable direct band gap photoluminescent organic semiconducting nanoparticles from lignite
Authors: B Manoj , Raj Ashlin M , Chirayil George Thomas 
Published: December 2017

AbstractFluorescent organic semiconducting dots (OSDs) with tunable particle size and surface functionality are synthesized from lignite by chemical oxidation method followed by ultra-sonication techniques and dialysis. The defects and oxygen functionalities play a vital role in the photoluminescent property of the synthesized nanoparticles along with quantum confinement effect. These nanomaterials are suitable for imaging and chemical sensing applications as there is no photobleaching and quenching even after a continuous UV exposure of 24 hours and storage of 2 years. The excellent excitation dependent luminescence of the synthesized carbon dots can be utilized for making a low-cost carbon-based sensor for Cu2+metal ions sensing. The OSDs show good ratiometric fluorescent sensing and can be used as a reliable probe for the detection of Cu2+ions. They exhibit excellent detection limit of copper ion in acidic solution to a very low concentration of 0.0089 nM. The fluorescent nanodots synthesized from such an abundant and cost-effective precursor exhibiting high copper ion sensitivity is being reported for the first time.
Attraction of Culex mosquitoes to aldehydes from human emanations
Authors: Leal Helena M. , Hwang Justin K. , Tan Kaiming , Leal Walter S. 
Published: December 2017

AbstractAnecdotes related to preferential mosquito bites are very common, but to date there is no complete explanation as to why one out of two people systematically receives more mosquito bites than the other when both are equally accessible. Here we tested the hypothesis that two constituents of skin emanations, 6-methyl-5-heptan-2-one (6-MHO) and geranylacetone (GA), are natural repellents and may account for differential attraction in different ratios. We studied skin emanations from two human subjects, confirmed in behavioral assays that female southern house mosquitoes are significantly more attracted to subject A (attractant) than to subject N (non-attractant), and tested their 6-MHO/GA ratios in a dual-choice olfactometer. Although repelling at high doses, 6-MHO/GA mixtures were not active at the levels emitted by human skin. We found, however, differential attraction elicited by the aldehydes in the ratios produced by subjects A and N. When tested in a dose commensurate with the level released from human skin and in the ratio produced by subject A, the aldehyde mixture significantly attracted mosquitoes. By contrast, an aldehyde mixture at the same ratio released by subject N did not attract mosquitoes. We, therefore, hypothesized that aldehydes may play a role in the commonly observed differential attraction.
Natural‐air‐cooled 5 kVA single‐phase GaN inverter with paralleled multilayer PCB magnetics
Authors: Meşe Hüseyin , Çadırcı Işık 
Published: December 2017

In this study, a systematic approach to the design and development of a high‐efficiency, natural‐air‐cooled, single‐phase inverter with a multilayer high‐current printed‐circuit board (PCB) magnetics is presented. The size and efficiency of inverters implemented with the silicon transistor technology have almost reached a certain limit. The use of wide bandgap power semiconductors, such as the silicon carbide metal–oxide–semiconductor field‐effect transistor and the gallium nitride (GaN) enhancement‐mode (e‐mode) transistor not only pushes further the efficiency limits, but also shrinks the inverter size. A new approach is proposed here in order to obtain a high‐efficiency inverter which relies basically upon the derivation of analytical expressions for the inverter losses as a function of the inverter modulation index, for the optimum transistor and highest switching frequency pair selection, and the design of the output filter based on a paralleled, multilayer PCB magnetics. In the developed 5 kVA single‐phase full‐bridge inverter, GaN e‐mode transistors are used to minimise the inverter losses and to decrease the cooling requirement, and size of the system. The proposed systematic design approach has been verified on the implemented 5 kVA, 50 kHz, naturally‐cooled GaN inverter, with a power density of 2.7 W/cm3 (44.3 W/inch3), and a full‐load efficiency of 98%.
Comparison of centralised and distributed battery energy storage systems in LV distribution networks on operational optimisation and financial benefits
Authors: Qiao Zhi , Yang Jin 
Published: December 2017

The integration of renewable energy sources and plug‐in electric vehicles (PEVs) into the existing low‐voltage (LV) distribution network at a high penetration level can cause reverse power flow, increased overall energy demand, network congestion, voltage rise/dip, transformer overloading and other operational issues. In this study, these potentially negative impacts caused by increasing penetration of distributed energy resources and PEVs are stochastically quantified based on a real practical 400 V distribution network as a case study. Battery energy storage (BES) is known to be a promising method for peak shaving and to provide network ancillary services. Two types of BES implementations aiming at distinctive charging and discharging targets without communication infrastructure or control centre are proposed and simulated. Optimisation results and potential financial profit of these two BES systems are compared and discussed in detail.
Release of Prometastatic Platelet-Derived Microparticles Induced by Breast Cancer Cells: A Novel Positive Feedback Mechanism for Metastasis
Authors: Zarà Marta , Guidetti Gianni , Boselli Daniela , Villa Chiara , Canobbio Ilaria , Seppi Claudio , Visconte Caterina , Canino Jessica , Torti Mauro 
Published: December 2017

AbstractCirculating platelets and platelet-derived microparticles are regulators of cancer metastasis. In this study, we show that breast cancer cells induce platelet aggregation and lead to the release of platelet-derived microparticles. Although able to cause comparable aggregation, the highly aggressive MDA-MB-231 cells were more potent than the poorly aggressive MCF7 cells in inducing platelet-derived microparticles release, which was comparable to that promoted by thrombin. MDA-MB-231 cells were able to bind and internalize both MCF7- and MDA-MB-231-induced platelet-derived microparticles with comparable efficiency. By contrast, MCF7 cells did not interact with either type of platelet-derived microparticles. Upon internalization, only platelet-derived microparticles released by platelet stimulation with MDA-MB-231 cells, but not those released upon stimulation with MCF7 cells, caused activation of MDA-MB-231 cells and promoted the phosphorylation of selected signaling proteins, including p38MAPK and myosin light chain. Accordingly, MDA-MB-231-induced, but not MCF7-induced, platelet-derived microparticles dose-dependently stimulated migration and invasion of targeted MDA-MB-231 cells. These results identify a novel paracrine positive feedback mechanism initiated by aggressive breast cancer cell types to potentiate their invasive phenotype through the release of platelet-derived microparticles.
Serum Sex Hormone Binding Globulin (SHBG) Relation with Different Components of Metabolic Syndrome in Men with Type 2 Diabetes
Authors: Siddiqui Khalid , Al-Rubeaan Khalid , Nawaz Shaik , Aburisheh Khaled , Alaabdin Anas , Tolba Ibrahim 
Published: December 2017

AbstractSex hormone binding globulin (SHBG) is demonstrated to be decreased in subjects with metabolic syndrome (MetS). The aim of the present study was to investigate the association of SHBG in relation to MetS components among men with type 2 diabetes (T2D). This cross-sectional study was carried out among 429 Saudi T2D male patients aged >30 years. Metabolic syndrome was defined using International Diabetes Federation (IDF) criteria. Fasting blood glucose (FBG), HbA1c, albumin, and lipid parameter were measured. Gonadal hormones, namely total testosterone, luteinizing hormone (LH), follicle-stimulating hormone (FSH), and SHBG were determined using ELISA. The SHBG levels of the MetS group was significantly lower than non-MetS group 47.25±31.03 nmol/l vs. 56.55±37.84 nmol/l; p=0.013. As the MetS score increases, SHBG and HDL levels decrease while weight, BMI, waist circumference, SBP, DBP, FBG, HbA1c, TC, and TG levels increase. SHBG correlated with age, BMI, TG, HDL, TT, free testosterone, and bio-available testosterone. This is the first study that provides detailed analyses of SHBG with MetS components in male diabetic subjects. The mean serum SHBG levels gradually declined with the addition of MetS components in T2D men. TT, free testosterone, and bio-available testosterone remained independently associated with SHBG by multivariable regression analysis.
Modelling disease in aquatic systems that are spread by processes operating at different temporal and spatial scales: examples from salmon aquaculture.
Authors: Murray A. G. , Salama N. K. G. 
Published: December 2017

Abstract
Disease is an important limitation on aquatic production, particularly for intensified aquaculture. Disease spread depends on behaviour of the pathogens on local scales and over short periods, their interaction with currents operating over many kilometres and days and the build-up of infection in populations over months and large geographical areas often spread by anthropogenic processes. Models are able to identify critical factors operating at different time and space scales in the spread of disease and use these to identify disease control measure. Models incorporating different levels of complexity are appropriate for simulating different diseases and for application for different purposes. Simple transmission models can be useful for high-level disease control policy but more complexity incorporating details of anthropogenic and hydrodynamic contacts may be required to inform management of specific groups and clusters of farms. Diseases affecting salmon aquaculture are used to explore application of modelling as this industry is relatively a well-documented and, for reasons of familiarity, examples tend to be taken from Scotland.