bluuebunny/crossref_metadata_2025_split huggingface dataset:
Catalytic Enantioselective Aza‐pinacol Rearrangement
Authors: Yu Yuanyuan , Li Jingwen , Jiang Long , Zhang Jing‐Ren , Zu Liansuo 
Published: June 2017

AbstractThe first catalytic enantioselective asymmetric aza‐pinacol rearrangement is reported. The reactions are catalyzed by a chiral phosphoric acid and proceed via a highly organized transition state involving a cyclic aza‐ortho‐xylylene intermediate to afford the indoline structures with good to excellent enantioselectivity. The synthetic utility of this method is demonstrated by the asymmetric synthesis of a key intermediate to the natural product minfiensine and the identification of a chiral lead compound to repress antibiotic resistance.
Living on the edge: Traits of freshwater fish species at risk in Canada
Authors: Glass William R. , Corkum Lynda D. , Mandrak Nicholas E. 
Published: June 2017

Abstract

The native ranges of many species in North America reach their northern extent in southern Canada, which results in several aquatic species with core populations found farther south being assessed as at risk by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) and receiving protection under the Species at Risk Act (SARA).
To determine traits that predict at‐risk status for freshwater fishes in Canada a classification and regression tree analysis was performed using a suite of ecological and life‐history traits, and the species’ distributions in Canada.
Range‐edge distribution in Canada was a significant predictor of a species assessed as at risk by COSEWIC and to be listed as at risk under SARA. Other predictive traits included Balon reproductive guild, reproductive age/maximum age ratio, and lifespan. Species with economic value were also not likely to be assessed as at risk by COSEWIC. Analyses showed greater inconsistency in listing status under SARA than COSEWIC assessment, and a bias toward not listing species, despite predicted at‐risk status, was evident.
The predictive models may prove useful in making future conservation decisions and highlight species that should have their status (re)assessed.
Enantioselective determination of R‐(−)‐manidipine and S‐(+)‐manidipine in human plasma by a sensitive and selective chiral LC–MS/MS assay
Authors: Adireddy Vinayender , Bimireddy Bhavani Prasanna Kumar , Ponneri Venkateswarlu 
Published: June 2017

AbstractA sensitive and selective liquid chromatography–tandem mass spectrometric (LC–MS/MS) assay method has been developed and validated for the enantioselective determination of manidipine in human plasma using isotope‐labeled compounds as internal standards. After solid‐phase extraction, R‐(−)‐manidipine and S‐(+)‐manidipine were chromatographed on a Chiralpack IC‐3 C18 column using a isocratic mobile phase composed of 2 mm ammonium bicarbonate and acetonitrile (15:85, v/v). The precursor ion to product ion transitions for the enantiomers and internal standards were monitored in the multiple reaction monitoring and positive ionization mode using an API‐4000 mass spectrometer. The method was linear over the concentration range of 0.05–10.2 ng/mL for both enantiomers. The precision and accuracy results over five concentration levels in five different batches were well within the acceptance limits. The mean extraction recovery was >80% for both enantiomers. A variety of stability tests were executed in plasma and in neat samples, which complies with the FDA guidelines. After complete validation, the method was successfully applied to a pharmacokinetic study of a manidipine 20 mg oral dose in 10 healthy South India subjects under fasting conditions. The assay reproducibility is shown through incurred samples reanalysis of 20 subject plasma samples.
Self‐Assembled Nano‐Immunostimulant for Synergistic Immune Activation
Authors: Sun Zhan‐Yi , Chen Pu‐Guang , Liu Yan‐Fang , Shi Lei , Zhang Bo‐Dou , Wu Jun‐Jun , Zhao Yu‐Fen , Chen Yong‐Xiang , Li Yan‐Mei 
Published: June 2017

AbstractImmunotherapy has become one of the most promising therapies for the treatment of diseases. Synthetic immunostimulants and nanomaterial immunostimulant systems are indispensable for the activation of the immune system in cancer immunotherapy. Herein, a strategy for preparing self‐assembled nano‐immunostimulants (SANIs) for synergistic immune activation is reported. Three immunostimulants self‐assemble into nanoparticles through electrostatic interactions. SANIs showed strong synergistic immunostimulation in macrophages. SANIs could also induce a strong antitumor immune response to inhibit tumor growth in mice and act as an efficient adjuvant of antitumor vaccines. Therefore, SANIs may be generally applied in cancer immunotherapy. This novel SANI strategy provides a new way for the development of both immunostimulants and ‐suppressants.
Cold interferes with male meiotic cytokinesis in Arabidopsis thaliana independently of the AHK2/3‐AHP2/3/5 cytokinin signaling module
Authors: Liu Bing , De Storme Nico , Geelen Danny 
Published: June 2017

AbstractPreviously we have shown that low temperature stress in Arabidopsis causes defects in microtubule organization and cytokinesis in male meiocytes, which leads to the formation of diploid pollen. Because cytokinin (CK) mediates multiple physiological responses to cold stress, we investigated whether CK signaling is involved in cold‐induced diploid pollen formation. To this end, we monitored male sporogenesis in a series of mutants defective in CK metabolism and signalling. Arabidopsis plants with altered CK homeostasis, that is, the ahk2‐2 ahk3‐3 double and the ahp2‐1 ahp3 ahp5‐2 triple mutant, were cold sensitive and displayed similar defective male meiotic cytokinesis as wild type plants upon cold stress. These findings demonstrate that the AHK2/3‐AHP2/3/5 CK‐signaling module is not required for cold‐induced ploidy stability of male gamete in Arabidopsis. Cytological analysis further revealed that the cold‐induced cytokinesis defects in the ahk2‐2 ahk3‐3 mutant correlated with irregular organization of the radial microtubule array (RMA) in tetrad microspores at the end of male meiosis. Contrary to the ahk and ahp mutants, Arabidopsis plants defective for ARR1, a downstream target of ahk and ahp mediated CK signalling, displayed higher cold‐tolerance of male meiotic cytokinesis program. We here suggest that the transcription regulator ARR1 may act independently from the CK AHK2/3‐AHP2/3/5 signaling module in conveying the cold response to male meiocytes.
Iron‐Catalyzed Olefin Metathesis with Low‐Valent Iron Alkylidenes
Authors: Mauksch Michael , Tsogoeva Svetlana B. 
Published: June 2017

AbstractInspired by recent reports of low‐valent iron‐complex‐catalyzed formal [2+2] cycloaddition of olefins, we demonstrate computationally that with such low‐valent iron complexes and with “strong” ligands, the olefin metathesis is also preferred over the undesired cyclopropanation side‐reaction, competition already studied by Hoffmann and co‐workers almost 40 years ago (J. Am. Chem. Soc. 1981, 103, 5582). The [2+2] cycloaddition step in metathesis propagation, which gives a Chauvin‐type metallacyclobutane intermediate, is proposed to proceed either via a planar four‐electron Craig–Möbius aromatic [π2s+π2s] transition‐state structure with a low barrier of 4.7 kcal mol−1 or, alternatively, via a twisted Zimmerman–Möbius aromatic [π2s+π2a] transition state with a 5.5 kcal mol−1 activation‐energy barrier, with respect to an “encounter” π‐complex minimum obtained from an FeII alkylidene and the entering olefin, while the corresponding triplet pathways are all disfavored.
Tribute to Fumio Oosawa the pioneer in actin biophysics
Authors: Pollard Thomas D. 
Published: June 2017

AbstractFumio Oosawa and his colleagues at Nagoya University laid the foundation for mechanistic studies of actin. Using relatively primitive tools they discovered that actin monomers assemble in a two‐step mechanism: highly unfavorable formation of small oligomeric nuclei followed by rapid elongation. Oosawa and his student Sadashi Hatano were the first to purify actin from a nonmuscle cell, Physarum polycephalum, initiating studies of the molecular mechanism of cellular movements.
Critical Evaluation of Native Electrospray Ionization Mass Spectrometry for Fragment‐Based Screening
Authors: Göth Melanie , Badock Volker , Weiske Jörg , Pagel Kevin , Kuropka Benno 
Published: June 2017

AbstractFragment‐based screening presents a promising alternative to high‐throughput screening and has gained great attention in recent years. So far, only a few studies have discussed mass spectrometry as a screening technology for fragments. Herein, we report the application of native electrospray ionization mass spectrometry (MS) for screening defined sets of fragments against four different target proteins. Fragments were selected from a primary screening conducted with a thermal shift assay (TSA) and represented different binding categories. Our data indicated that, beside specific complex formation, many fragments show extensive multiple binding and also charge‐state shifts. Both of these factors complicate automated data analysis and decrease the attractiveness of native MS as a primary screening tool for fragments. A comparison of the hits identified by native MS and TSA showed good agreement for two of the proteins. Furthermore, we discuss general challenges, including the determination of an optimal fragment concentration and the question of how to rank fragment hits according to their affinity. In conclusion, we consider native MS to be a highly valuable tool for the validation and deeper investigation of promising fragment hits rather than a method for primary screening.
Altered expression of IGF‐I system in neurons of the inflamed spinal cord during acute experimental autoimmune encephalomyelitis
Authors: Parvaneh Tafreshi Azita , Talebi Farideh , Ghorbani Samira , Bernard Claude , Noorbakhsh Farshid 
Published: June 2017

AbstractThere is growing evidence that the impaired IGF‐I system contributes to neurodegeneration. In this study, we examined the spinal cords of the EAE, the animal model of multiple sclerosis, to see if the expression of the IGF‐I system is altered. To induce EAE, C57/BL6 mice were immunized with the Hooke lab MOG kit, sacrificed at the peak of the disease and their spinal cords were examined for the immunoreactivities (ir) of the IGF‐I, IGF binding protein‐1 (IGFBP‐1) and glycogen synthase kinase 3β (GSK3β), as one major downstream molecule in the IGF‐I signaling. Although neurons in the non EAE spinal cords did not show the IGF‐I immunoreactivity, they were numerously positive for the IGFBP‐1. In the inflamed EAE spinal cord however, the patterns of expressions were reversed, that is, a significant increased number of IGF‐I expressing neurons versus a reduced number of IGFBP‐1 positive neurons. Moreover, while nearly all IGF‐I‐ir neurons expressed GSK3β, some expressed it more intensely. Considering our previous finding where we showed a significant reduced number of the inactive (phosphorylated) but not that of the total GSK3β expressing neurons in the EAE spinal cord, it is conceivable that the intense total GSK3β expression in the IGF‐I‐ir neurons belongs to the active form of GSK3β known to exert neuroinflammatory effects. We therefore suggest that the altered expression of the IGF‐I system including GSK3β in spinal cord neurons might involve in pathophysiological events during the EAE.
Physically consistent data assimilation method based on feedback control for patient‐specific blood flow analysis
Authors: Ii Satoshi , Adib Mohd Azrul Hisham Mohd , Watanabe Yoshiyuki , Wada Shigeo 
Published: June 2017

AbstractThis paper presents a novel data assimilation method for patient‐specific blood flow analysis based on feedback control theory called the physically consistent feedback control‐based data assimilation (PFC‐DA) method. In the PFC‐DA method, the signal, which is the residual error term of the velocity when comparing the numerical and reference measurement data, is cast as a source term in a Poisson equation for the scalar potential field that induces flow in a closed system. The pressure values at the inlet and outlet boundaries are recursively calculated by this scalar potential field. Hence, the flow field is physically consistent because it is driven by the calculated inlet and outlet pressures, without any artificial body forces. As compared with existing variational approaches, although this PFC‐DA method does not guarantee the optimal solution, only one additional Poisson equation for the scalar potential field is required, providing a remarkable improvement for such a small additional computational cost at every iteration. Through numerical examples for 2D and 3D exact flow fields, with both noise‐free and noisy reference data as well as a blood flow analysis on a cerebral aneurysm using actual patient data, the robustness and accuracy of this approach is shown. Moreover, the feasibility of a patient‐specific practical blood flow analysis is demonstrated.
Solid‐State Lithium Conductors for Lithium Metal Batteries Based on Electrospun Nanofiber/Plastic Crystal Composites
Authors: Zhou Yundong , Wang Xiaoen , Zhu Haijin , Yoshizawa‐Fujita Masahiro , Miyachi Yukari , Armand Michel , Forsyth Maria , Greene George W. , Pringle Jennifer M. , Howlett Patrick C. 
Published: June 2017

AbstractOrganic ionic plastic crystals (OIPCs) are a class of solid‐state electrolytes with good thermal stability, non‐flammability, non‐volatility, and good electrochemical stability. When prepared in a composite with electrospun polyvinylidene fluoride (PVdF) nanofibers, a 1:1 mixture of the OIPC N‐ethyl‐N‐methylpyrrolidinium bis(fluorosulfonyl)imide ([C2mpyr][FSI]) and lithium bis(fluorosulfonyl)imide (LiFSI) produced a free‐standing, robust solid‐state electrolyte. These high‐concentration Li‐containing electrolyte membranes had a transference number of 0.37(±0.02) and supported stable lithium symmetric‐cell cycling at a current density of 0.13 mA cm−2. The effect of incorporating PVdF in the Li‐containing plastic crystal was investigated for different ratios of PVdF and [Li][FSI]/[C2mpyr][FSI]. In addition, Li|LiNi1/3Co1/3Mn1/3O2 cells were prepared and cycled at ambient temperature and displayed a good rate performance and stability.
Self‐Assembled Dendritic Pt Nanostructure with High‐Index Facets as Highly Active and Durable Electrocatalyst for Oxygen Reduction
Authors: Jang Youngjin , Choi Kwang‐Hyun , Chung Dong Young , Lee Ji Eun , Jung Namgee , Sung Yung‐Eun 
Published: June 2017

AbstractThe durability issues of Pt catalyst should be resolved for the commercialization of proton exchange membrane fuel cells. Nanocrystal structures with high‐index facets have been recently explored to solve the critical durability problem of fuel cell catalysts as Pt catalysts with high‐index facets can preserve the ordered surfaces without change of the original structures. However, it is very difficult to develop effective and practical synthetic methods for Pt‐based nanostructures with high‐index facets. The current study describes a simple one‐pot synthesis of self‐assembled dendritic Pt nanostructures with electrochemically active and stable high‐index facets. Pt nanodendrites exhibited 2 times higher ORR activity and superior durability (only 3.0 % activity loss after 10 000 potential cycles) than a commercial Pt/C. The enhanced catalytic performance was elucidated by the formation of well‐organized dendritic structures with plenty of reactive interfaces among 5 nm‐sized Pt particles and the coexistence of low‐ and high‐index facets on the particles.
Data‐driven programmatic approach to analysis of basophil activation tests
Authors: Patil Sarita U. , Calatroni Agustin , Schneider Michael , Steinbrecher Johanna , Smith Neal , Washburn Cecilia , Ma Alex , Shreffler Wayne G. 
Published: June 2017

BackgroundConventional data analysis of flow cytometry‐based basophil activation testing requires repetitive, labor‐intensive analysis that hampers efforts to standardize testing for clinical applications. Using an open‐source platform, we developed and implemented a programmatic approach to the analysis of the basophil activation test (BAT) by flow cytometry.MethodsUsing the BÜHLMANN FlowCAST® assay, peripheral blood from peanut allergic patients undergoing oral immunotherapy was incubated with peanut allergens (Arah1, Arah2, Arah6, whole peanut extract) and stained with fluorescent antibodies to CCR3 and CD63 for the development of a data‐driven programmatic analysis using Bioconductor and R. Basophil identification using clustering and classification was validated using manually gated comparisons in an experimental subset. Reproducibility of CD63 upregulation set on unstimulated or anti‐FcERI stimulated basophils was compared.ResultsBAT analysis of 294 experiments was successful in 91.5% using the above approach, with a total of 7,166 individual basophil activation tests from 269 experiments. We estimate this represents a net saving of 1340 min of labor by a skilled operator. Medium‐based gating correlated to respective manual gating more closely than anti‐FcERI based gating (R = 0.96 vs. R = 0.84, P < 0.001). Only 2% of the basophil activation results were significantly different from manual gating. Quality measures of the experiments and other measures of basophil activation were also provided by the analysis.ConclusionsWe present a novel data‐driven flow cytometric platform for the analysis of clinical basophil activation testing, providing a high throughput objective approach to basophil activation analysis. © 2017 International Clinical Cytometry Society
Capacity planning framework for mobile network operator cloud using analytical performance model
Authors: Raei Hassan 
Published: June 2017

SummaryA mobile network operator cloud (MNOC), solely or with the help of public clouds, provides the computational resources in the form of virtual machines on physical machines (PMs) to handle heavy tasks, which are offloaded by the subscribers. Definitely, cost is a constant source of worry for an MNOC. In fact, although a large number of used PMs of the MNOC and public clouds decreases the penalty cost of request rejection, other associated costs, such as infrastructure, power consumption, cooling, and virtual machine instances of public clouds, are imposed on the MNOC. Therefore, to minimize the overall cost, finding the optimal number of required PMs in all participant clouds, including the MNOC and public clouds, is recognized as an important issue. To deal with this issue, in the present paper, using analytical performance model of a MNOC, a capacity planning framework is proposed. Specifically, this framework solves a cost optimization problem using a simulated annealing algorithm. Numerical results demonstrate the ability of the proposed framework to identify the optimal solution within an acceptable duration of the time.
Optimization of recombinant β‐glucuronidase hydrolysis and quantification of eight urinary cannabinoids and metabolites by liquid chromatography tandem mass spectrometry
Authors: Sempio Cristina , Scheidweiler Karl B. , Barnes Allan J. , Huestis Marilyn A. 
Published: June 2017

Prolonged urinary cannabinoid excretion in chronic frequent cannabis users confounds identification of recent cannabis intake that may be important in treatment, workplace, clinical, and forensic testing programs. In addition, differentiation of synthetic Δ9‐tetrahydrocannabinol (THC) intake from cannabis plant products might be an important interpretive issue. THC, 11‐hydroxy‐THC (11‐OH‐THC) and 11‐nor‐9‐carboxy‐THC (THCCOOH) urine concentrations were evaluated during previous controlled cannabis administration studies following tandem alkaline/E. coli β‐glucuronidase hydrolysis. We optimized recombinant β‐glucuronidase enzymatic urinary hydrolysis before simultaneous liquid chromatography tandem mass spectrometry (LC–MS/MS) quantification of THC, 11‐OH‐THC, THCCOOH, cannabidiol (CBD), cannabinol (CBN), cannabigerol (CBG), tetrahydrocannabivarin (THCV) and 11‐nor‐9‐carboxy‐THCV (THCVCOOH) in urine. Enzyme amount, incubation time and temperature, buffer molarity and pH were optimized using pooled urine samples collected during a National Institute on Drug Abuse, Institutional Review Board‐approved clinical study. Optimized cannabinoid hydrolysis with recombinant β‐glucuronidase was achieved with 2000 IU enzyme, 2 M pH 6.8 sodium phosphate buffer, and 0.2 mL urine at 37°C for 16 h. The LC–MS/MS quantification method for hydrolyzed urinary cannabinoids was validated per the Scientific Working Group on Toxicology guidelines. Linear ranges were 1–250 μg/L for THC and CBG, 2–250 μg/L for 11‐OH‐THC, CBD, CBN, THCV and THCVCOOH, and 1–500 μg/L for THCCOOH. Inter‐batch analytical bias was 92.4–112.4%, imprecision 4.4–9.3% CV (n = 25), extraction efficiency 44.3–97.1% and matrix effect −29.6 to 1.8% (n = 10). The method was utilized to analyze urine specimens collected during our controlled smoked, vaporized, and edible cannabis administration study to improve interpretation of urine cannabinoid test results.
Relative Selection Strength: Quantifying effect size in habitat‐ and step‐selection inference
Authors: Avgar Tal , Lele Subhash R. , Keim Jonah L. , Boyce Mark S. 
Published: June 2017

AbstractHabitat‐selection analysis lacks an appropriate measure of the ecological significance of the statistical estimates—a practical interpretation of the magnitude of the selection coefficients. There is a need for a standard approach that allows relating the strength of selection to a change in habitat conditions across space, a quantification of the estimated effect size that can be compared both within and across studies. We offer a solution, based on the epidemiological risk ratio, which we term the relative selection strength (RSS). For a “used‐available” design with an exponential selection function, the RSS provides an appropriate interpretation of the magnitude of the estimated selection coefficients, conditional on all other covariates being fixed. This is similar to the interpretation of the regression coefficients in any multivariable regression analysis. Although technically correct, the conditional interpretation may be inappropriate when attempting to predict habitat use across a given landscape. Hence, we also provide a simple graphical tool that communicates both the conditional and average effect of the change in one covariate. The average‐effect plot answers the question: What is the average change in the space use probability as we change the covariate of interest, while averaging over possible values of other covariates? We illustrate an application of the average‐effect plot for the average effect of distance to road on space use for elk (Cervus elaphus) during the hunting season. We provide a list of potentially useful RSS expressions and discuss the utility of the RSS in the context of common ecological applications.