bluuebunny/crossref_metadata_2025 huggingface dataset:
Does Twitter Increase Perceived Police Legitimacy?
Authors: Grimmelikhuijsen Stephan G. , Meijer Albert J.
Published: April 2015

Social media use has become increasingly popular among police forces. The literature suggests that social media use can increase perceived police legitimacy by enabling transparency and participation. Employing data from a large and representative survey of Dutch citizens (N = 4,492), this article tests whether and how social media use affects perceived legitimacy for a major social media platform, Twitter. A negligible number of citizens engage online with the police, and thus the findings reveal no positive relationship between participation and perceived legitimacy. The article shows that by enhancing transparency, Twitter does increase perceived police legitimacy, albeit to a limited extent. Subsequent analysis of the mechanism shows both an affective and a cognitive path from social media use to legitimacy. Overall, the findings suggest that establishing a direct channel with citizens and using it to communicate successes does help the police strengthen their legitimacy, but only slightly and for a small group of interested citizens.
Serving Clients When the Server Crashes: How Frontline Workers Cope with E‐Government Challenges
Authors: Tummers Lars , Rocco Philip
Published: April 2015

Implementing e‐government in the contemporary American state is challenging. E‐government places high technical demands on agencies and citizens in an environment of budget austerity and political polarization. Governments developing e‐government policies often mobilize frontline workers—also termed “street‐level bureaucrats”—to help citizens gain access to services. However, we know little about how frontline workers cope in these challenging circumstances. This article fills this gap by examining frontline workers implementing the Patient Protection and Affordable Care Act. Based on a qualitative analysis, the authors find that frontline workers “move toward clients” when coping with stress: they bend the rules, work overtime, and collaborate in order to help clients. They are less inclined to “move away” or “move against” clients, for instance, through rigid rule following and rationing. In other words, frontline workers try to serve clients, even “when the server crashes.” Frontline workers, then, can play a vital role in the successful implementation of e‐government policies.
Patient and practitioner perceptions of student participation in private practice consultations: A mixed-methods study
Authors: Kent Fiona , Richards Karen , Haines Terry , Morgan Prue , Maloney Stephen , Keating Jennifer
Published: April 2015

The majority of undergraduate physiotherapy clinical education occurs in the public sector in Australia, despite the fact that about half of all graduates enter private practice upon graduation. Private practice physiotherapists provide primary care services for a wide range of conditions, with associated opportunities for student education. The barriers to addressing the imbalance between clinical education and graduate practice warrant investigation. This study combined quantitative patient survey data with qualitative practitioner interview data. Sixty-three patient surveys were collected from four private practices, and practitioner educators (n=4) at these sites were interviewed. The survey data revealed that patients tend to be agreeable to student presence in a consultation but expressed varying preferences regarding the degree of student involvement in their care. Practitioners reported benefits associated with taking on an educator role, including screening students for future recruitment. They also reported barriers to increasing education opportunities for education in private practice, including lack of time, cost and limited skills of students. A need to better prepare practitioners for the role of educator was identified. In conclusion, there is a subset of private practice patients that is agreeable to students providing health services. Routine identification of these patients, and better preparation of both educators and students, may improve the current lack of clinical learning opportunities in private, primary care and physiotherapy clinics.
Protein kinase G–regulated production of H
2
S governs oxygen sensing
Authors: Yuan Guoxiang , Vasavda Chirag , Peng Ying-Jie , Makarenko Vladislav V. , Raghuraman Gayatri , Nanduri Jayasri , Gadalla Moataz M. , Semenza Gregg L. , Kumar Ganesh K. , Snyder Solomon H. , Prabhakar Nanduri R.
Published: April 2015

Complex interplay between three gases—oxygen, carbon monoxide, and hydrogen sulfide—is necessary to control breathing.
Origins of Yersinia pestis Sensitivity to the Arylomycin Antibiotics and the Inhibition of Type I Signal Peptidase
Authors: Steed Danielle B. , Liu Jian , Wasbrough Elizabeth , Miller Lynda , Halasohoris Stephanie , Miller Jeremy , Somerville Brandon , Hershfield Jeremy R. , Romesberg Floyd E.
Published: April 2015

Yersinia pestis
is the etiologic agent of the plague. Reports of
Y. pestis
strains that are resistant to each of the currently approved first-line and prophylactic treatments point to the urgent need to develop novel antibiotics with activity against the pathogen. We previously reported that
Y. pestis
strain KIM6+, unlike most
Enterobacteriaceae
, is susceptible to the arylomycins, a novel class of natural-product lipopeptide antibiotics that inhibit signal peptidase I (SPase). In this study, we show that the arylomycin activity is conserved against a broad range of
Y. pestis
strains and confirm that it results from the inhibition of SPase. We next investigated the origins of this unique arylomycin sensitivity and found that it does not result from an increased affinity of the
Y. pestis
SPase for the antibiotic and that alterations to each component of the
Y. pestis
lipopolysaccharide—O antigen, core, and lipid A—make at most only a small contribution. Instead, the origins of the sensitivity can be traced to an increased dependence on SPase activity that results from high levels of protein secretion under physiological conditions. These results highlight the potential of targeting protein secretion in cases where there is a heavy reliance on this process and also have implications for the development of the arylomycins as an antibiotic with activity against
Y. pestis
and potentially other Gram-negative pathogens.
Validation and Pharmacokinetic Application of a High-Performance Liquid Chromatographic Technique for Determining the Concentrations of Amodiaquine and Its Metabolite in Plasma of Patients Treated with Oral Fixed-Dose Amodiaquine-Artesunate Combination in Areas of Malaria Endemicity
Authors: Adedeji Olumuyiwa N. , Bolaji Oluseye O. , Falade Catherine O. , Osonuga Odusoga A. , Ademowo Olusegun G.
Published: April 2015

Artemisinin-based combination therapies (ACTs) have been adopted by most African countries, including Nigeria, as first-line treatments for uncomplicated falciparum malaria. Fixed-dose combinations of these ACTs, amodiaquine-artesunate (FDC AQAS) and artemether-lumefantrine (AL), were introduced in Nigeria to improve compliance and achieve positive outcomes of malaria treatment. In order to achieve clinical success with AQAS, we developed and validated a simple and sensitive high-performance liquid chromatography (HPLC) method with UV detection for determination of amodiaquine (AQ) and desethylamodiaquine (DAQ) in plasma using liquid-liquid extraction of the drugs with diethyl ether following protein precipitation with acetonitrile. Chromatographic separation was achieved using an Agilent Zorbax C
18
column and a mobile phase consisting of distilled water-methanol (80:20 [vol/vol]) with 2% (vol/vol) triethylamine, pH 2.2, at a flow rate of 1 ml/min. Calibration curves in spiked plasma were linear from 100 to 1,000 ng/ml (
r
> 0.99) for both AQ and DAQ. The limit of detection was 1 ng (sample size, 20 μl). The intra- and interday coefficients of variation at 150, 300, and 900 ng/ml ranged from 1.3 to 4.8%, and the biases were between 6.4 and 9.5%. The mean extraction recoveries of AQ and DAQ were 80.0% and 68.9%, respectively. The results for the pharmacokinetic parameters of DAQ following oral administration of FDC AQAS (612/200 mg) for 3 days in female and male patients with uncomplicated falciparum malaria showed that the maximum plasma concentrations (
C
max
) (740 ± 197 versus 767 ± 185 ng/ml), areas under the plasma concentration-time curve (AUC) (185,080 ± 20,813 versus 184,940 ± 16,370 h · ng/ml), and elimination half-life values (
T
1/2
) (212 ± 1.14 versus 214 ± 0.84 h) were similar (
P
> 0.05).
Autophagy Inhibitors as a Potential Antiamoebic Treatment for Acanthamoeba Keratitis
Authors: Moon Eun-Kyung , Kim So-Hee , Hong Yeonchul , Chung Dong-Il , Goo Youn-Kyoung , Kong Hyun-Hee
Published: April 2015

Acanthamoeba
cysts are resistant to extreme physical and chemical conditions. Autophagy is an essential pathway for encystation of
Acanthamoeba
cells. To evaluate the possibility of an autophagic
Acanthamoeba
encystation mechanism, we evaluated autophagy inhibitors, such as 3-methyladenine (3MA), LY294002, wortmannin, bafilomycin A, and chloroquine. Among these autophagy inhibitors, the use of 3MA and chloroquine showed a significant reduction in the encystation ratio in
Acanthamoeba
cells. Wortmannin also inhibited the formation of mature cysts, while LY294002 and bafilomycin A did not affect the encystation of
Acanthamoeba
cells. Transmission electron microscopy revealed that 3MA and wortmannin inhibited autophagy formation and that chloroquine interfered with the formation of autolysosomes. Inhibition of autophagy or autolysosome formation resulted in a significant block in the encystation in
Acanthamoeba
cells. Clinical treatment with 0.02% polyhexamethylene biguanide (PHMB) showed high cytopathic effects on
Acanthamoeba
trophozoites and cysts; however, it also revealed high cytopathic effects on human corneal epithelial cells. In this study, we investigated effects of the combination of a low (0.00125%) concentration of PHMB with each of the autophagy inhibitors 3MA, wortmannin, and chloroquine on
Acanthamoeba
and human corneal epithelial cells. These new combination treatments showed low cytopathic effects on human corneal cells and high cytopathic effects on
Acanthamoeba
cells. Taken together, these results provide fundamental information for optimizing the treatment of
Acanthamoeba
keratitis.
An Invertron-Like Linear Plasmid Mediates Intracellular Survival and Virulence in Bovine Isolates of Rhodococcus equi
Authors: Valero-Rello Ana , Hapeshi Alexia , Anastasi Elisa , Alvarez Sonsiray , Scortti Mariela , Meijer Wim G. , MacArthur Iain , Vázquez-Boland José A.
Published: April 2015

We report a novel host-associated virulence plasmid in
Rhodococcus equi
, pVAPN, carried by bovine isolates of this facultative intracellular pathogenic actinomycete. Surprisingly, pVAPN is a 120-kb invertron-like linear replicon unrelated to the circular virulence plasmids associated with equine (pVAPA) and porcine (pVAPB variant)
R. equi
isolates. pVAPN is similar to the linear plasmid pNSL1 from
Rhodococcus
sp. NS1 and harbors six new
vap
multigene family members (
vapN
to
vapS
) in a
vap
pathogenicity locus presumably acquired via
en bloc
mobilization from a direct predecessor of equine pVAPA. Loss of pVAPN rendered
R. equi
avirulent in macrophages and mice. Mating experiments using an
in vivo
transconjugant selection strategy demonstrated that pVAPN transfer is sufficient to confer virulence to a plasmid-cured
R. equi
recipient. Phylogenetic analyses assigned the
vap
multigene family complement from pVAPN, pVAPA, and pVAPB to seven monophyletic clades, each containing plasmid type-specific allelic variants of a precursor
vap
gene carried by the nearest
vap
island ancestor. Deletion of
vapN
, the predicted “bovine-type” allelic counterpart of
vapA
, essential for virulence in pVAPA, abrogated pVAPN-mediated intramacrophage proliferation and virulence in mice. Our findings support a model in which
R. equi
virulence is conferred by host-adapted plasmids. Their central role is mediating intracellular proliferation in macrophages, promoted by a key
vap
determinant present in the common ancestor of the plasmid-specific
vap
islands, with host tropism as a secondary trait selected during coevolution with specific animal species.
A Heterologous Reporter Defines the Role of the Tetanus Toxin Interchain Disulfide in Light-Chain Translocation
Authors: Zuverink Madison , Chen Chen , Przedpelski Amanda , Blum Faith C. , Barbieri Joseph T.
Published: April 2015

Botulinum neurotoxins (BoNTs) and tetanus toxin (TeNT) are the most potent toxins for humans and elicit unique pathologies due to their ability to traffic within motor neurons. BoNTs act locally within motor neurons to elicit flaccid paralysis, while retrograde TeNT traffics to inhibitory neurons within the central nervous system (CNS) to elicit spastic paralysis. BoNT and TeNT are dichain proteins linked by an interchain disulfide bond comprised of an N-terminal catalytic light chain (LC) and a C-terminal heavy chain (HC) that encodes an LC translocation domain (HCT) and a receptor-binding domain (HCR). LC translocation is the least understood property of toxin action, but it involves low pH, proteolysis, and an intact interchain disulfide bridge. Recently, Pirazzini et al. (FEBS Lett 587:150–155, 2013,
http://dx.doi.org/10.1016/j.febslet.2012.11.007
) observed that inhibitors of thioredoxin reductase (TrxR) blocked TeNT and BoNT action in cerebellar granular neurons. In the current study, an atoxic TeNT LC translocation reporter was engineered by fusing β-lactamase to the N terminus of TeNT [βlac-TeNT(RY)] to investigate LC translocation in primary cortical neurons and Neuro-2a cells. βlac-TeNT(RY) retained the interchain disulfide bond, showed ganglioside-dependent binding to neurons, required acidification to promote βlac translocation, and was sensitive to auranofin, an inhibitor of thioredoxin reductase. Mutation of βlac-TeNT(RY) at C439S and C467S eliminated the interchain disulfide bond and inhibited βlac translocation. These data support the requirement of an intact interchain disulfide for LC translocation and imply that disulfide reduction is a prerequisite for LC delivery into the host cytosol. The data also support a model that LC translocation proceeds from the C to the N terminus. βlac-TeNT(RY) is the first reporter system to measure translocation by an AB single-chain toxin in intact cells.
Comprehensive Functional Analysis of the 18 Vibrio cholerae N16961 Toxin-Antitoxin Systems Substantiates Their Role in Stabilizing the Superintegron
Authors: Iqbal Naeem , Guérout Anne-Marie , Krin Evelyne , Le Roux Frédérique , Mazel Didier
Published: April 2015

The role of chromosomal toxin-antitoxin (TA) systems, which are ubiquitous within the genomes of free-living bacteria, is still debated. We have scanned theVibrio choleraeN16961 genome for class 2 TA genes and identified 18 gene pair candidates. Interestingly, all but one are located in the chromosome 2 superintegron (SI). The single TA found outside the SI is located on chromosome 1 and is related to the well-characterized HipAB family, which is known to play a role in antibiotic persistence. We investigated this clustering within the SI and its possible biological consequences by performing a comprehensive functional analysis on all of the putative TA systems. We demonstrate that the 18 TAs identified encode functional toxins and that their cognate antitoxins are able to neutralize their deleterious effects when expressed inEscherichia coli. In addition, we reveal that the 17 predicted TA systems of the SI are transcribed and expressed in their native context from their own promoters, a situation rarely found in integron cassettes. We tested the possibility of interactions between noncognate pairs of all toxins and antitoxins and found no cross-interaction between any of the different TAs. Although these observations do not exclude other roles, they clearly strengthen the role of TA systems in stabilizing the massive SI cassette array ofV. cholerae.

IMPORTANCEThe chromosomal toxin-antitoxin systems have been shown to play various, sometimes contradictory roles, ranging from genomic stabilization to bacterial survival via persistence. Determining the interactions between TA systems hosted within the same bacteria is essential to understand the hierarchy between these different roles. We identify here the full set of class 2 TAs carried in theVibrio choleraeN16961 genome and found they are all, with a single exception, located in the chromosome 2 superintegron. Their characterization, in terms of functionality, expression, and possible cross-interactions, supports their main role as being the stabilization of the 176-cassette-long array of the superintegron but does not exclude dual roles, such as stress response elements, persistence, and bacteriophage defense through abortive infection mechanisms.
Sodium chlorite – iodide – acetylacetone oscillation reaction investigated by UV-Vis spectrophotometry
Authors: Chen Jingjing , Shi Laishun , Li Demei , Wang Ying , Lin Shujie , Zhang Yifan
Published: April 2015

A new sodium chlorite – iodide – acetylacetone chemical oscillatory reaction has been studied by the UV-Vis spectrophotometric method. The initial concentrations of acetylacetone, sodium chlorite, iodide, and sulfuric acid and the pH value have great influence on the oscillation observed at a wavelength of 570 nm for the starch–triiodide complex. There is a pre-oscillatory or induction stage and the amplitude and number of oscillations depend on the initial concentration of the reactants. Equations for the starch–triiodide complex reaction rate change with reaction time and the initial concentrations in the oscillation stage were obtained. The induction time decreases linearly with the initial concentration of acetylacetone or sodium chlorite but increases linearly with the initial concentration of sulfuric acid. The oscillation reaction can be accelerated by increasing the reaction temperature. The apparent activation energies at the induction stage and the oscillation stage were 61.02 and 61.36 kJ/mol, respectively, indicating that the two stages have similar reaction mechanisms. Generating the enol isomer by keto–enol tautomerism is an important step to constrain the time of the induction period.
Optical resonant RKKY interaction in nanosystems
Authors: Feng Peng , Xie Jianqiao
Published: April 2015

Conduction electron spins interacting with magnetic impurity spins can lead to an indirect exchange interaction between magnetic impurities in nonmagnetic metals or semiconductors, namely, RKKY interaction. In general, this RKKY coupling is too weak to apply on devices. In this paper, we find that when a laser field of appropriate frequency irradiates the nanosystems, it can greatly strengthen the RKKY interaction. This is the so-called optical resonant RKKY interaction. We give the resonant frequencies for different size samples, and calculate the exchange integrals for these samples on the near-resonant conditions. This optical resonant RKKY coupling may be strong enough to guarantee its application on spintronic devices.
Topological T-duality for torus bundles with monodromy
Authors: Baraglia David
Published: April 2015

We give a simplified definition of topological T-duality that applies to arbitrary torus bundles. The new definition does not involve Chern classes or spectral sequences, only gerbes and morphisms between them. All the familiar topological conditions for T-duals are shown to follow. We determine necessary and sufficient conditions for existence of a T-dual in the case of affine torus bundles. This is general enough to include all principal torus bundles as well as torus bundles with arbitrary monodromy representations. We show that isomorphisms in twisted cohomology, twisted K-theory and of Courant algebroids persist in this general setting. We also give an example where twisted K-theory groups can be computed by iterating T-duality.
Multivacuum states in a fermionic gap equation with massive gluons and confinement
Authors: Capdevilla R. M.
Published: April 2015

We study the nontrivial solutions of the Quantum Chromodynamics (QCD) fermionic gap equation (FGE) including the contribution of dynamically massive gluons and the confining propagator proposed by Cornwall. Without the confining propagator, in the case of nonrunning gluon mass (mg), we found the multivacuum solutions (replicas) reported in the literature and we were able to define limits on mg for dynamical chiral symmetry breaking (CSB). On the other side, when considering the running in the gluon mass the vacuum replicas are absent in the limits on mg where the chiral symmetry is broken. In the pure confining sector, the multivacuum states are always absent so it is said that only one stable solution for the gap equation is found as claimed in previous analysis using different approaches. Finally, in the case of the complete gap equation i.e. with both contributions, the vacuum replicas are also absent in both cases; with constant and with running gluon mass.
The spinless relativistic kink-like problem
Authors: Lucha Wolfgang , Schöberl Franz F.
Published: April 2015

We constrain the possible bound-state solutions of the spinless Salpeter equation (the most obvious semirelativistic generalization of the nonrelativistic Schrödinger equation) with an interaction between the bound-state constituents given by the kink-like potential (a central potential of hyperbolic-tangent form) by formulating a bunch of very elementary boundary conditions to be satisfied by all solutions of the eigenvalue problem posed by a bound-state equation of this type, only to learn that all results produced by a procedure very much liked by some quantum-theory practitioners prove to be in severe conflict with our expectations.
A holographic superconductor model with higher correction terms
Authors: Peng Yan , Liu Guohua
Published: April 2015

We study general models for holographic superconductors with higher correction terms of the scalar field in the four-dimensional AdS black hole background including the matter fields' backreaction on the metric. We explore the effects of the model parameters on the scalar condensation and find that different values of model parameters can determine the order of phase transitions. Moreover, we find that the higher correction terms provide richer physics in the phase transition diagram.
Dependence of sinusoidal electric field effect on neuronal morphological properties
Authors: Wei Xile , Yin Xiaowei , Lu Meili , Yi Guosheng , Wang Jiang
Published: April 2015

In this paper, the neuronal firing patterns under extracellular sinusoidal electric field (EF) are investigated based on a reduced two-compartment model with focus on the effects of morphological and internal coupling parameters. We observe that the neuron can exhibit bursting, synchronous firing and subthreshold oscillation depending on EF amplitude A and frequency f. Furthermore, neuronal firing properties change obviously over a range of morphological parameter p. As p increases, the firing region expands first and then diminishes gradually until it disappears in the observed (A, f) parameter space and the transition from bursting to synchronous firing is also markedly distinct. Meanwhile, the morphological parameter also has significant effects on the EF threshold for triggering neuronal spikes. Unlike morphological parameter, though the internal coupling conductance gc can also induce some changes in firing behavior and EF threshold, it cannot qualitatively change neuronal dynamical properties. All these results demonstrate that neuronal morphology plays a crucial role in neuronal responses to sinusoidal EF.
The one-way information deficit for a class of two-qubit states
Authors: Eftekhari H. , Faizi E.
Published: April 2015

So far, one-way information deficit (OWID) has been calculated explicitly only for Bell-diagonal states and the four-parameter family of X-states with additional assumptions and expressions for more general quantum states are not known. In this paper, we derive explicit expressions for OWID for a larger class of two-qubit states, namely, a five-parameter family of two-qubit states. The dynamic behavior of the OWID under decoherence channel is investigated and it is shown that the OWID is more robust against the decoherence than the entanglement.
Reciprocal NUT spacetimes
Authors: Momeni Davood , Chattopadhyay Surajit , Myrzakulov Ratbay
Published: April 2015

In this paper, we study the Ehlers' transformation (sometimes called gravitational duality rotation) for reciprocal static metrics. First, we introduce the concept of reciprocal metric. We prove a theorem which shows how we can construct a certain new static solution of Einstein field equations using a seed metric. Later, we investigate the family of stationary spacetimes of such reciprocal metrics. The key here is a theorem from Ehlers', which relates any static vacuum solution to a unique stationary metric. The stationary metric has a magnetic charge. The spacetime represents Newman-Unti-Tamburino (NUT) solutions. Since any stationary spacetime can be decomposed into a 1 + 3 time-space decomposition, Einstein field equations for any stationary spacetime can be written in the form of Maxwell's equations for gravitoelectromagnetic fields. Further, we show that this set of equations is invariant under reciprocal transformations. An additional point is that the NUT charge changes the sign. As an instructive example, by starting from the reciprocal Schwarzschild as a spherically symmetric solution and reciprocal Morgan–Morgan disk model as seed metrics we find their corresponding stationary spacetimes. Starting from any static seed metric, performing the reciprocal transformation and by applying an additional Ehlers' transformation we obtain a family of NUT spaces with negative NUT factor (reciprocal NUT factors).
Some Einstein nilmanifolds with skew torsion arising in CR geometry
Authors: Dileo Giulia , Lotta Antonio
Published: April 2015

We describe some new examples of nilmanifolds admitting an Einstein with skew torsion invariant Riemannian metric. These are affine CR quadrics, whose CR structure is preserved by the characteristic connection.
Numerical Analysis of Frictionless Nano-Contact Problems Based on Surface Elasticity
Authors: Attia Mohamed A. , El-Shafei Ahmed G. , Mahmoud Fatin F.
Published: April 2015

A nonlinear finite element model is developed to predict the response of frictionless contact of isotropic, elastic nano-bodies incorporating the effect of surface energy. The boundary value problem is formulated based on the classical theory of linear elasticity of the bulk material, while the complete Gurtin–Murdoch constitutive relation is adopted to accommodate the effect of surface energy. The Lagrange multiplier approach is employed to enforce inequality contact constraints without any need of an appropriate value for the penalty parameter, where the contact forces are treated as independent variables. The proposed finite element model accounts for both advancing and receding contact problems. The output results are compared favorably with those published analytical solutions. The influence of surface energy and its size-dependency on the behavior of conformal and nonconformal conformal/nonconformal nano-contact systems is demonstrated by carrying out by analyzing three different contact problems.
A Review on Flow Characteristics of Refrigerant and Oil Mixture in a Heat Pump System
Authors: Kim Hak Soo , Kim Min Soo
Published: April 2015

This paper presents a comprehensive review of oil retention and performance of oil separator in a heat pump system. Liquid volume fraction model, viscous film model and analytical model from continuity and momentum equations for predicting the oil retention amount in a heat pump system are reviewed. In addition, weighing a test section, using an oil injection and extraction device and optical analysis for measuring the oil retention amount are introduced and experimental results are analyzed. Numerical studies which used commercial tools for computational fluid dynamics or suggested a new model by simplifying the flow in cyclone separator are reviewed. Effects of droplet size and angular velocity of gas phase flow in cyclone separator on the performance are discussed. Experimental methods for measuring the efficiency of oil separator are introduced, and theoretical analysis on the efficiency and pressure drop of cyclone separator is suggested.
Rethinking the Ancient Sulfur Cycle
Authors: Fike David A. , Bradley Alexander S. , Rose Catherine V.
Published: April 2015

The sulfur biogeochemical cycle integrates the metabolic activity of multiple microbial pathways (e.g., sulfate reduction, disproportionation, and sulfide oxidation) along with abiotic reactions and geological processes that cycle sulfur through various reservoirs. The sulfur cycle impacts the global carbon cycle and climate primarily through the remineralization of organic carbon. Over geological timescales, cycling of sulfur is closely tied to the redox state of Earth's exosphere through the burial of oxidized (sulfate) and reduced (sulfide) sulfur species in marine sediments. Biological sulfur cycling is associated with isotopic fractionations that can be used to trace the fluxes through various metabolic pathways. The resulting isotopic data provide insights into sulfur cycling in both modern and ancient environments via isotopic signatures in sedimentary sulfate and sulfide phases. Here, we review the deep-time δ34S record of marine sulfates and sulfides in light of recent advances in understanding how isotopic signatures are generated by microbial activity, how these signatures are encoded in marine sediments, and how they may be altered following deposition. The resulting picture shows a sulfur cycle intimately coupled to ambient carbon cycling, where sulfur isotopic records preserved in sedimentary rocks are critically dependent on sedimentological and geochemical conditions (e.g., iron availability) during deposition.
General Cortical and Special Prefrontal Connections: Principles from Structure to Function
Authors: Barbas Helen
Published: April 2015

How is the vast brain communication system organized? A structural model relates connections to laminar differences between linked areas. The model is based on the principle of systematic structural variation in the cortex, extending from the simplest limbic cortices to eulaminate areas with elaborate lamination. The model accounts for laminar patterns and for the strength and topography of connections between nearby or distant cortices and subcortical structures, exemplified quantitatively for the principal and special prefrontal connections. Widespread connections of limbic areas and focal connections of eulaminate areas yield a broad range of circuit patterns for diverse functions. These diverse pathways innervate excitatory and functionally distinct inhibitory neurons, providing the basis for differential recruitment of areas for flexible behavior. Systematic structural variation likely emerges by timing differences in the development of distinct areas and has important implications for altered connections in diseases of developmental origin.
The Types of Retinal Ganglion Cells: Current Status and Implications for Neuronal Classification
Authors: Sanes Joshua R. , Masland Richard H.
Published: April 2015

In the retina, photoreceptors pass visual information to interneurons, which process it and pass it to retinal ganglion cells (RGCs). Axons of RGCs then travel through the optic nerve, telling the rest of the brain all it will ever know about the visual world. Research over the past several decades has made clear that most RGCs are not merely light detectors, but rather feature detectors, which send a diverse set of parallel, highly processed images of the world on to higher centers. Here, we review progress in classification of RGCs by physiological, morphological, and molecular criteria, making a particular effort to distinguish those cell types that are definitive from those for which information is partial. We focus on the mouse, in which molecular and genetic methods are most advanced. We argue that there are around 30 RGC types and that we can now account for well over half of all RGCs. We also use RGCs to examine the general problem of neuronal classification, arguing that insights and methods from the retina can guide the classification enterprise in other brain regions.
Cortical Folding: When, Where, How, and Why?
Authors: Striedter Georg F. , Srinivasan Shyam , Monuki Edwin S.
Published: April 2015

Why the cerebral cortex folds in some mammals but not in others has long fascinated and mystified neurobiologists. Over the past century—especially the past decade—researchers have used theory and experiment to support different folding mechanisms such as tissue buckling from mechanical stress, axon tethering, localized proliferation, and external constraints. In this review, we synthesize these mechanisms into a unifying framework and introduce a hitherto unappreciated mechanism, the radial intercalation of new neurons at the top of the cortical plate, as a likely proximate force for tangential expansion that then leads to cortical folding. The interplay between radial intercalation and various biasing factors, such as local variations in proliferation rate and connectivity, can explain the formation of both random and stereotypically positioned folds.
Epidemiological Investigations on Cystic Echinococcosis in North-West (Sidi Kacem Province) Morocco: Infection in Ruminants
Authors: El Berbri Ikhlass , Petavy Anne Françoise , Umhang Gerald , Bouslikhane Mohammed , Fassi Fihri Ouafaa , Boué Franck , Dakkak Allal
Published: April 2015

Despite alarming statistics on cystic echinococcosis (CE) in humans and the importance of dog and ruminant populations, no epidemiological investigations have been performed on CE in Sidi Kacem Province (North-West of Morocco). A part of large research project was devoted to determine the status of CE in ruminants. This paper reports the results of the investigations carried out in the 10 abattoirs of this region, over four successive years (April 2009–March 2013). A total of 1,302 sheep, 652 head of cattle, and 136 goats were postmortem examined and hydatid cysts were collected and examined. The overall CE prevalence of infection was 42.9% in cattle, 11.0% in sheep, and 1.5% in goats. The prevalence shows significant association with age in sheep and cattle; sheep above 3 years and cattle above 5 years are highly infected (64.0% and 72.2%, resp.). Only liver and lungs are found to be infected. Molecular analyses identified G1, G2, and G3 of E. granulosus sensu stricto in liver and lung samples. Cyst fertility was significantly higher in sheep (54.9%) than in cattle (50.3%). These findings suggest that control measures should target not only sheep but also cattle.
Influences of Two Land-Surface Schemes on RegCM4 Precipitation Simulations over the Tibetan Plateau
Authors: Wang Xuejia , Yang Meixue , Pang Guojin
Published: April 2015

The effects of different RegCM4 land-surface schemes on Tibetan Plateau (TP) precipitation simulations were investigated. Two groups of ten-year (1992–2001) simulation experiments (hereafter referred to as BATS and CLM) were performed based on two land-surface schemes (BATS and CLM3.5, resp.) and were compared with observed data using the same domain, initial, and lateral boundary conditions, cumulus convective scheme, and spatial resolution. The results showed that the CLM monthly precipitation more closely matched the observed data compared with BATS. BATS and CLM both overestimated summer precipitation in the northern TP but underestimated summer precipitation in the southern TP. However, CLM, because of its detailed land-surface process descriptions, reduced the overestimated precipitation areas and magnitudes of BATS. Compared to CN05, the regional average summer precipitation in BATS and CLM was overestimated by 34.7% and underestimated by 24.7%, respectively. Higher soil moisture, evapotranspiration, and heating effects in the BATS experiment triggered changes in atmospheric circulation patterns over the TP. Moreover, BATS simulated the lower atmosphere as warmer and more humid and the upper atmosphere (~150 hPa) as colder than the CLM simulations; these characteristics likely increased the instability for moist convection and produced more summer precipitation.
Benchtop Technologies for Circulating Tumor Cells Separation Based on Biophysical Properties
Authors: Low Wan Shi , Wan Abas Wan Abu Bakar
Published: April 2015

Circulating tumor cells (CTCs) are tumor cells that have detached from primary tumor site and are transported via the circulation system. The importance of CTCs as prognostic biomarker is leveraged when multiple studies found that patient with cutoff of 5 CTCs per 7.5 mL blood has poor survival rate. Despite its clinical relevance, the isolation and characterization of CTCs can be quite challenging due to their large morphological variability and the rare presence of CTCs within the blood. Numerous methods have been employed and discussed in the literature for CTCs separation. In this paper, we will focus on label free CTCs isolation methods, in which the biophysical and biomechanical properties of cells (e.g., size, deformability, and electricity) are exploited for CTCs detection. To assess the present state of various isolation methods, key performance metrics such as capture efficiency, cell viability, and throughput will be reported. Finally, we discuss the challenges and future perspectives of CTC isolation technologies.
Biosignals Analysis for Kidney Function Effect Analysis of Fennel Aromatherapy
Authors: Kim Bong-Hyun , Cho Dong-Uk , Seo Ssang-Hee
Published: April 2015

Human effort in order to enjoy a healthy life is diverse. IT technology to these analyzes, the results of development efforts, it has been applied. Therefore, I use the care and maintenance diagnostic health management and prevention than treatment. In particular, the aromatherapy treatment easy to use without the side effects there is no irritation, are widely used in modern society. In this paper, we measured the aroma effect by applying a biosignal analysis techniques; an experiment was performed to analyze. In particular, we design methods and processes of research based on the theory aroma that affect renal function. Therefore, in this paper, measuring the biosignals and after fennel aromatherapy treatment prior to the enforcement of the mutual comparison, through the analysis, studies were carried out to analyze the effect of fennel aromatherapy therapy on kidney function.
High Performance Electrocatalysts Based on Pt Nanoarchitecture for Fuel Cell Applications
Authors: Lee Young-Woo , Cha SeungNam , Park Kyung-Won , Sohn Jung Inn , Kim Jong Min
Published: April 2015

Fuel cells, converting chemical energy from fuels into electricity directly without the need for combustion, are promising energy conversion devices for their potential applications as environmentally friendly, energy efficient power sources. However, to take fuel cell technology forward towards commercialization, we need to achieve further improvements in electrocatalyst technology, which can play an extremely important role in essentially determining cost‐effectiveness, performance, and durability. In particular, platinum‐ (Pt‐) based electrocatalyst approaches have been extensively investigated and actively pursued to meet those demands as an ideal fuel cell catalyst due to their most outstanding activity for both cathode oxygen reduction reactions and anode fuel oxidation reactions. In this review, we will address important issues and recent progress in the development of Pt‐based catalysts, their synthesis, and characterization. We will also review snapshots of research that are focused on essential dynamics aspects of electrocatalytic reactions, such as the shape effects on the catalytic activity of Pt‐based nanostructures, the relationships between structural morphology of Pt‐based nanostructures and electrochemical reactions on both cathode and anode electrodes, and the effects of composition and electronic structure of Pt‐based catalysts on electrochemical reaction properties of fuel cells.
A Time Scales Approach to Coinfection by Opportunistic Diseases
Authors: Marvá Marcos , Venturino Ezio , Bravo de la Parra Rafael
Published: April 2015

Traditional biomedical approaches treat diseases in isolation, but the importance of synergistic disease interactions is now recognized. As a first step we present and analyze a simple coinfection model for two diseases simultaneously affecting a population. The host population is affected by theprimary disease, a long-term infection whose dynamics is described by a SIS model with demography, which facilitates individuals acquiring a second disease,secondary(or opportunistic)disease. The secondary disease is instead a short-term infection affecting only the primary infected individuals. Its dynamics is also represented by a SIS model with no demography. To distinguish between short- and long-term infection the complete model is written as a two-time-scale system. The primary disease acts at the slow time scale while the secondary disease does at the fast one, allowing a dimension reduction of the system and making its analysis tractable. We show that an opportunistic disease outbreak might change drastically the outcome of the primary epidemic process, although it does among the outcomes allowed by the primary disease. We have found situations in which either acting on the opportunistic disease transmission or recovery rates or controlling the susceptible and infected population size allows eradicating/promoting disease endemicity.
Nonenzymatic Reactions above Phospholipid Surfaces of Biological Membranes: Reactivity of Phospholipids and Their Oxidation Derivatives
Authors: Solís-Calero Christian , Ortega-Castro Joaquín , Frau Juan , Muñoz Francisco
Published: April 2015

Phospholipids play multiple and essential roles in cells, as components of biological membranes. Although phospholipid bilayers provide the supporting matrix and surface for many enzymatic reactions, their inherent reactivity and possible catalytic role have not been highlighted. As other biomolecules, phospholipids are frequent targets of nonenzymatic modifications by reactive substances including oxidants and glycating agents which conduct to the formation of advanced lipoxidation end products (ALEs) and advanced glycation end products (AGEs). There are some theoretical studies about the mechanisms of reactions related to these processes on phosphatidylethanolamine surfaces, which hypothesize that cell membrane phospholipids surface environment could enhance some reactions through a catalyst effect. On the other hand, the phospholipid bilayers are susceptible to oxidative damage by oxidant agents as reactive oxygen species (ROS). Molecular dynamics simulations performed on phospholipid bilayers models, which include modified phospholipids by these reactions and subsequent reactions that conduct to formation of ALEs and AGEs, have revealed changes in the molecular interactions and biophysical properties of these bilayers as consequence of these reactions. Then, more studies are desirable which could correlate the biophysics of modified phospholipids with metabolism in processes such as aging and diseases such as diabetes, atherosclerosis, and Alzheimer’s disease.
The Electrical and Mechanical Properties of Porous Anodic 6061‐T6 Aluminum Alloy Oxide Film
Authors: Cheng Tsung-Chieh , Chou Chu-Chiang
Published: April 2015

The properties of the growth of the 6061‐T6 aluminum alloy oxide were studied using sulfuric acid anodization. The parameters for the manufacturing process include electrolyte categories, electrolyte concentration, and operating voltages. The results showed that the aluminum oxides obtained by anodization process are mainly amorphous structure and the anodic current density is an important factor affecting the rate of response for oxygen and aluminum ions in barrier. In this experiment, polish process is very important to stable the anodic aluminum oxide film and then it will get the better properties of anodic film. Besides, when using sulfuric acid as the electrolyte, the increase of anodic voltage also increases the rate of reaction which increases the mechanical and electrical properties of anodic oxide film, but too large applied anodic voltage will reduce the mechanical and electrical properties of film because of the crack of the anodic oxide film.
A New Improved Kurtogram and Its Application to Bearing Fault Diagnosis
Authors: Zhang Xinghui , Kang Jianshe , Xiao Lei , Zhao Jianmin , Teng Hongzhi
Published: April 2015

A new improved Kurtogram was proposed in this paper. Instead of Kurtosis, correlated Kurtosis of envelope signal extracted from the wavelet packet node was used as an indicator to determine the optimal frequency band. Correlated Kurtosis helps to determine the fault related impulse signals not affected by other unrelated signal components. Finally, two simulated and three experimental bearing fault cases are used to validate the effectiveness of proposed method and to compare with other similar methods. The results demonstrate it can locate resonant frequency band with a high reliability than two previous developed methods by Lei et al. and Wang et al. especially for the incipient faults under low load.
Immunomodulation and Anti-Inflammatory Effects of Garlic Compounds
Authors: Arreola Rodrigo , Quintero-Fabián Saray , López-Roa Rocío Ivette , Flores-Gutiérrez Enrique Octavio , Reyes-Grajeda Juan Pablo , Carrera-Quintanar Lucrecia , Ortuño-Sahagún Daniel
Published: April 2015

The benefits of garlic to health have been proclaimed for centuries; however, only recently haveAllium sativumand its derivatives been proposed as promising candidates for maintaining the homeostasis of the immune system. The complex biochemistry of garlic makes it possible for variations in processing to yield different preparations with differences in final composition and compound proportion. In this review, we assess the most recent experimental results, which indicate that garlic appears to enhance the functioning of the immune system by stimulating certain cell types, such as macrophages, lymphocytes, natural killer (NK) cells, dendritic cells, and eosinophils, by mechanisms including modulation of cytokine secretion, immunoglobulin production, phagocytosis, and macrophage activation. Finally, because immune dysfunction plays an important role in the development and progress of several diseases, we critically examined immunoregulation by garlic extracts and compounds isolated, which can contribute to the treatment and prevention of pathologies such as obesity, metabolic syndrome, cardiovascular disorders, gastric ulcer, and even cancer. We concluded thatA. sativummodulates cytokine secretion and that such modulation may provide a mechanism of action for many of their therapeutic effects.