bluuebunny/crossref_metadata_2025 huggingface dataset:
Networked Chemoreceptors Benefit Bacterial Chemotaxis Performance
Authors: Frank Vered , Piñas Germán E. , Cohen Harel , Parkinson John S. , Vaknin Ady
Published: December 2016

Motile bacteria use large receptor arrays to detect and follow chemical gradients in their environment. Extended receptor arrays, composed of networked signaling complexes, promote cooperative stimulus control of their associated signaling kinases. Here, we used structural lesions at the communication interface between core complexes to create an
Escherichia coli
strain with functional but dispersed signaling complexes. This strain allowed us to directly study how networking of signaling complexes affects chemotactic signaling and gradient-tracking performance. We demonstrate that networking of receptor complexes provides bacterial cells with about 10-fold-heightened detection sensitivity to attractants while maintaining a wide dynamic range over which receptor adaptational modifications can tune response sensitivity. These advantages proved especially critical for chemotaxis toward an attractant source under conditions in which bacteria are unable to alter the attractant gradient.

IMPORTANCE
Chemoreceptor arrays are found in many motile bacteria. However, although our understanding of bacterial chemotaxis is quite detailed, the signaling and behavioral advantages of networked receptor arrays had not been directly studied in cells. We have recently shown that lesions in a key interface of the
E. coli
receptor array diminish physical connections and functional coupling between core signaling complexes while maintaining their basic signaling capacity. In this study, we exploited an interface 2 mutant to show, for the first time, that coupling between core complexes substantially enhances stimulus detection and chemotaxis performance.
Cytochrome
bd
-Dependent Bioenergetics and Antinitrosative Defenses in
Salmonella
Pathogenesis
Authors: Jones-Carson Jessica , Husain Maroof , Liu Lin , Orlicky David J. , Vázquez-Torres Andrés
Published: December 2016

In the course of an infection,
Salmonella enterica
occupies diverse anatomical sites with various concentrations of oxygen (O
2
) and nitric oxide (NO). These diatomic gases compete for binding to catalytic metal groups of quinol oxidases.
Enterobacteriaceae
express two evolutionarily distinct classes of quinol oxidases that differ in affinity for O
2
and NO as well as stoichiometry of H
+
translocated across the cytoplasmic membrane. The investigations presented here show that the dual function of bacterial cytochrome
bd
in bioenergetics and antinitrosative defense enhances
Salmonella
virulence. The high affinity of cytochrome
bd
for O
2
optimizes respiratory rates in hypoxic cultures, and thus, this quinol oxidase maximizes bacterial growth under O
2
-limiting conditions. Our investigations also indicate that cytochrome
bd
, rather than cytochrome
bo
, is an intrinsic component of the adaptive antinitrosative toolbox of
Salmonella
. Accordingly, induction of cytochrome
bd
helps
Salmonella
grow and respire in the presence of inhibitory NO. The combined antinitrosative defenses of cytochrome
bd
and the flavohemoglobin Hmp account for a great part of the adaptations that help
Salmonella
recover from the antimicrobial activity of NO. Moreover, the antinitrosative defenses of cytochrome
bd
and flavohemoglobin Hmp synergize to promote
Salmonella
growth in systemic tissues. Collectively, our investigations indicate that cytochrome
bd
is a critical means by which
Salmonella
resists the nitrosative stress that is engendered in the innate response of mammalian hosts while it concomitantly allows for proper O
2
utilization in tissue hypoxia.

IMPORTANCE
It is becoming quite apparent that metabolism is critically important to the virulence potential of pathogenic microorganisms. Bacterial cells use a variety of terminal electron acceptors to power electron transport chains and metabolic processes. Of all the electron acceptors available to bacteria, utilization of O
2
yields the most energy while diversifying the type of substrates that a pathogen can use. Recent investigations have demonstrated important roles for
bd
-type quinol oxidases with high affinity for O
2
in bacterial pathogenesis. The investigations presented here have revealed that cytochrome
bd
potentiates virulence of a clinically relevant bacterial pathogen by fueling bioenergetics of prokaryotic cells while protecting the respiratory chain against NO toxicity. The adaptive antinitrosative defenses afforded by cytochrome
bd
synergize with other NO-detoxifying systems to preserve cellular bioenergetics, thereby promoting bacterial virulence in tissue hypoxia.
Strain Prioritization and Genome Mining for Enediyne Natural Products
Authors: Yan Xiaohui , Ge Huiming , Huang Tingting , Hindra  , Yang Dong , Teng Qihui , Crnovčić Ivana , Li Xiuling , Rudolf Jeffrey D. , Lohman Jeremy R. , Gansemans Yannick , Zhu Xiangcheng , Huang Yong , Zhao Li-Xing , Jiang Yi , Van Nieuwerburgh Filip , Rader Christoph , Duan Yanwen , Shen Ben
Published: December 2016

The enediyne family of natural products has had a profound impact on modern chemistry, biology, and medicine, and yet only 11 enediynes have been structurally characterized to date. Here we report a genome survey of 3,400 actinomycetes, identifying 81 strains that harbor genes encoding the enediyne polyketide synthase cassettes that could be grouped into 28 distinct clades based on phylogenetic analysis. Genome sequencing of 31 representative strains confirmed that each clade harbors a distinct enediyne biosynthetic gene cluster. A genome neighborhood network allows prediction of new structural features and biosynthetic insights that could be exploited for enediyne discovery. We confirmed one clade as new C-1027 producers, with a significantly higher C-1027 titer than the original producer, and discovered a new family of enediyne natural products, the tiancimycins (TNMs), that exhibit potent cytotoxicity against a broad spectrum of cancer cell lines. Our results demonstrate the feasibility of rapid discovery of new enediynes from a large strain collection.

IMPORTANCE
Recent advances in microbial genomics clearly revealed that the biosynthetic potential of soil actinomycetes to produce enediynes is underappreciated. A great challenge is to develop innovative methods to discover new enediynes and produce them in sufficient quantities for chemical, biological, and clinical investigations. This work demonstrated the feasibility of rapid discovery of new enediynes from a large strain collection. The new C-1027 producers, with a significantly higher C-1027 titer than the original producer, will impact the practical supply of this important drug lead. The TNMs, with their extremely potent cytotoxicity against various cancer cells and their rapid and complete cancer cell killing characteristics, in comparison with the payloads used in FDA-approved antibody-drug conjugates (ADCs), are poised to be exploited as payload candidates for the next generation of anticancer ADCs. Follow-up studies on the other identified hits promise the discovery of new enediynes, radically expanding the chemical space for the enediyne family.
Epidemiology and Host Factors
Authors: Mehta Jay B. , Dutt Asim K.
Published: December 2016

In 2014, WHO reported approximately 9.6 million new cases of tuberculosis (TB) in the world, more than half of which are contributed by developing countries in Asia and Africa. Lack of modern diagnostic tools, underreporting of the new cases and underutilization of directly observed therapy (DOT) remain a concern in developing countries. Transient resurgence of TB during the HIV epidemic has subsided and the annual decline has resumed in developed countries including the USA. In 2014 though, the rate of decline has slowed down resulting in leveling of TB incidence in the USA. In developed countries like the USA, the incidence of TB remains high in those with certain risk factors for TB. This group includes immunocompromised patients, particularly those with positive HIV infection. Others at high risk include those with diabetes, cancer, those taking immunosuppressive drugs, and those with other medical conditions that reduce host immunity. If we look at age and ethnicity, elderly patients are at higher risk of developing TB. African-American, foreign-born, and homeless populations are also at higher risk of developing tuberculosis. Virulence of the mycobacteria, and immunological and genetically mediated factors are also mentioned, but these topics are not the primary goal of this article. This review, thus discusses the epidemiology, host factors, and those at high risk for developing active TB. A brief review of the current trends in drug resistance of mycobacteria is also presented.
Diabetes and Tuberculosis
Authors: Restrepo Blanca I.
Published: December 2016

The increase in type 2 diabetes mellitus (DM) patients in countries where tuberculosis (TB) is also endemic has led to the reemerging importance of DM as a risk factor for TB. DM causes a 3-fold increase in TB risk and a 2-fold increase in adverse TB treatment outcomes. Given the sheer numbers of DM patients worldwide, there are now more TB patients with TB-DM comorbidity than TB-HIV coinfection. There is an urgent need to implement strategies for TB prevention and control among the millions of DM patients exposed toMycobacterium tuberculosis. This chapter summarizes the current epidemiological, clinical, and immunological knowledge on TB and DM and their clinical and public health implications. These include the underlying mechanisms for TB risk in DM patients and their clinical and sociodemographic characteristics that distinguish them from TB patients without DM. TB-DM comorbidity is posing a new challenge for integrating the short-term care for TB with the long-term care for DM, particularly in low- and middle-income countries.
Biologic Agents and Tuberculosis
Authors: Dobler Claudia C.
Published: December 2016

Treatment with biologic agents, in particular tumor necrosis factor alpha (TNF-α) inhibitors, is associated with an increased risk of tuberculosis (TB), and screening and treatment for latent TB infection (LTBI) in patients undergoing such treatment is therefore indicated. The risk of TB associated with different biologics varies significantly, with the highest relative risks, 29.3 and 18.6, associated with adalimumab and infliximab, respectively. The risk of TB with newer TNF-α inhibitors and other biologics appears to be lower. Performance of LTBI screening tests is affected by immune-mediated inflammatory diseases and immunosuppressive therapy in patients due to commence TNF-α inhibitor treatment. Interferon gamma release assays (IGRAs) have a higher specificity than the tuberculin skin test (TST) in patients with Bacillus Calmette–Guérin (BCG) vaccination and have probably a better sensitivity than TST in immunosuppressed patients. LTBI screening programs prior to commencement of anti-TNF-α treatment significantly reduce the incidence of TB, but the optimal screening algorithm, in particular the question of whether a combination of IGRA and TST or a single test only should be used, is a matter of ongoing debate. Use of TST in combination with IGRA is justified to increase sensitivity. Repeat testing for LTBI should be limited to patients at increased risk of TB. If TB develops during anti-TNF-α treatment, it is more likely to be disseminated and extrapulmonary than are other TB cases. Discontinuation of anti-TNF-α treatment in patients diagnosed with TB is associated with an increased risk of immune reconstitution inflammatory syndrome, which is probably best managed by reintroduction of anti-TNF-α treatment.
Feed-forward regulation of self-selected exercise intensity in response to different rates of arterial deoxygenation
Authors: Farra Saro D.
Published: December 2016

Arterial desaturation impairs exercise performance in a dose-dependent manner. However, new theories of exercise-induced fatigue suggest that increasing rates of arterial deoxygenation augment the fatigue response during exercise. The purpose of this dissertation is to clarify if self-selected exercise intensity, while exercising at a constant rate of perceived exertion (RPE), is sensitive to alterations in the absolute arterial saturation (SPO2) and/or the rate of change in SPO2. Subjects performed constant RPE exercise for 30 min. They were instructed to adjust their exercise intensity during the trial to maintain their RPE at 5 on Borg’s 10-point scale. Subjects engaged in continuous bilateral, isokinetic cycling and intermittent, unilateral, isometric knee-extension. The fraction of inspired oxygen was reduced to desaturate arterial blood from starting values (>98%) to 70%. This desaturation occurred linearly over 3 target time periods (FAST, 5 min; MED, 15 min; SLOW, 25 min). The rate of arterial desaturation was significantly different between each of the 3 conditions. During cycling exercise, PO (FAST = 2.8 ± 2.1 W·% SPO2−1; MED = 2.5 ± 1.8 W·% SPO2−1; SLOW = 1.8 ± 1.6 W·% SPO2−1; P < 0.001) and surface electromyography (sEMG) of the vastus medialis (FAST = 1.3 ± 0.6%·% SPO2−1; MED = 1.1 ± 0.5%·% SPO2−1; SLOW = 0.7 ± 0.7%·% SPO2−1; P < 0.001) decreased at significantly different rates. Post hoc comparisons revealed that the rates of decline in PO and sEMG during FAST and MED were similar, and both were greater than SLOW. However, during isometric knee extension exercise, the level of force production and sEMG remained similar across saturation levels. These results confirm that decreases in absolute SPO2 impair self-selected exercise intensity and that faster desaturation rates magnify that impairment, but only when a large muscle mass is engaged. These findings suggest that the rate of arterial deoxygenation independently influences exercise performance and that the central depressant effect may be a function of the metabolic strain associated with hypoxia, rather than the hypoxia per se.
A new proportionality-based back-calculation approach, which employs traditional forms of growth equations, improves estimates of length at age
Authors: Ashworth Eloïse C. , Hesp S. Alex , Hall Norman G.
Published: December 2016

The performance of a new proportionality-based back-calculation approach, describing the relationship among length, otolith size, and age using traditional growth curves and assuming a bivariate distribution of deviations from those curves, was evaluated. Cross-validation was used for six teleost species to compare predictions of expected lengths or otolith sizes at age, given otolith size or length, respectively, with those of other proportionality-based approaches that incorporate age. For four species, and particularly Acanthopagrus butcheri when using a biological intercept, better estimates were produced using the new model than were produced using the regression equations in the other back-calculation approaches. Back-calculated lengths for A. butcheri estimated using this model were more consistent with observed lengths, particularly when employing a biological intercept, than those obtained using other proportionality-based approaches and also a constraint-based approach known to produce reliable estimates. By selecting somatic and otolith growth curves from a suite of alternatives to better describe the relationships among length, otolith size, and age, the new approach is likely to produce more reliable estimates of back-calculated length for other species.
Reduced expression of HCN channels in the sinoatrial node of streptozotocin-induced diabetic rats
Authors: Huang Xin , Zhong Nier , Zhang Hong , Ma Aiqun , Yuan Zuyi , Guo Ning
Published: December 2016

Diabetes mellitus (DM) is associated with an electrical remodeling of the heart, increasing the risk of arrhythmias. However, knowledge of electrical remodeling in the sinoatrial node (SAN) by DM is limited. We investigated the expression of HCN channel isoforms, HCN1–HCN4, in SAN from streptozotocin (STZ)-induced diabetic rats and the age-matched controls. We found that the STZ-induced diabetic rats have a lower intrinsic heart rate, a lengthened sinoatrial conduction time, and rate-corrected maximal sinoatrial node recovery time in vivo as well as a longer cycle length (CL) in vitro, as compared with the control. Optical mapping of the SAN demonstrated an inferior leading pacemaker site, reduced SAN conduction velocity and diastolic depolarization slope, and a longer action potential duration in the STZ-induced diabetic rats than in the control. The transcripts and proteins of HCN2 and HCN4 in diabetic SAN were reduced. Specific blockade of HCN channels by 3 μmol/L ivabradine significantly prolonged the CL of a Langendorff heart by 18% in the diabetic rats and 26% in the control. The reduced expression of HCN channel isoforms in the SAN of the STZ-induced diabetic rat may be an important contributor to the reduced SAN function in DM.
Olanzapine alleviates oxidative stress in the liver of socially isolated rats
Authors: Stanisavljevic Andrijana , Peric Ivana , Pantelic Marija , Filipovic Dragana M.
Published: December 2016

Olanzapine, an antipsychotic drug, is used to treat depressive disorder, but its effects on the liver, the main site of drug metabolism, still remain elusive. We studied the effects of 3 weeks of olanzapine treatment (7.5 mg/kg per day) on the malondialdehyde (MDA) and protein carbonyl (PCO) contents, protein expression of copper/zinc superoxide dismutase (CuZnSOD), and activity of total superoxide dismutase (SOD), as well as catalase (CAT) protein expression and activity levels in the liver cytosol of rats exposed to 6 weeks of chronic social isolation (CSIS), which causes depressive- and anxiety-like behaviors. Increased cytosolic MDA in CSIS rats (vehicle- or olanzapine-treated) indicated hepatic oxidative stress. Increase in PCO and CAT activity associated with unchanged total SOD activity following CSIS also confirm the presence of oxidative stress. Chronic olanzapine treatment in CSIS prevented increase in PCO without an effect on MDA content. Increased SOD activity in olanzapine-treated (controls and CSIS) groups compared with corresponding vehicle-treated groups and decreased CAT activity in olanzapine-treated CSIS rats compared with vehicle-treated CSIS group was found. The data suggest that chronic olanzapine treatment has a protective effect on hepatic protein oxidation and improves antioxidant defense. The beneficial effects of olanzapine may be due to its free radical scavenging properties and antioxidant activity.
Arsenic in groundwater in the southern lowlands of Nepal and its mitigation options: a review
Authors: Mueller Barbara
Published: December 2016

As in several other countries of Southeast Asia (namely Bangladesh, India, Myanmar, China, Vietnam, and Cambodia) arsenic (As) concentrations in the groundwater of the lowlands of Nepal (the so called Terai) can reach concentrations that are unsafe to humans using the groundwater as drinking water. Whereas Bangladesh has received much international attention concerning the As crisis, Nepal was more or less neglected. The first report about As contamination of the groundwater above toxic levels in Nepal was published in 1999. Twenty-four percent of samples analyzed (n = 18 635) from the Terai Basin exceeded the WHO guideline of 10 μg/L. Since the first overall survey from 2001, only sporadic information on the situation has been published. The geological and geochemical conditions favour the release of the contaminant as As can be easily solubilized in groundwaters depending on pH, redox conditions, temperature, and solution composition. The thin alluvial aquifers of the Terai are some of the most severely As contaminated. These sediments constituting a hugh proportion of the Terai aquifers are derived from two main sources: (i) sediments deposited by large rivers that erode the upper Himalayan crystalline rocks, and (ii) weathered meta-sediments carried by smaller rivers originating in the Siwalik forehills. The generally low redox potential and low SO42− and high DOC, PO43−, and HCO3− concentrations in groundwater signify ongoing microbial-mediated redox processes favoring As mobilization in the aquifer. Other geochemical processes, e.g., Fe-oxyhydroxide reduction and carbonate dissolution, are also responsible for high As occurrence in groundwaters. Originally, gagri filters (a two-filter system with chemical powder) and later iron (Fe)-assisted biosand filters were commonly used to remove As and Fe from well water in Nepal—these two options were believed to be the best treatment option at household levels. This review focus on the description of the overall situation, including geogenic issues, occurrence of As in the sediments of the Terai, mechanisms for the release of As to the groundwater, and mitigation options.
Natural variation in CIRCADIAN CLOCK ASSOCIATED 1 is associated with flowering time in Brassica rapa
Authors: Yi Hankuil , Li Xiaonan , Lee Seong Ho , Nou Ill-Sup , Lim Yong Pyo , Hur Yoonkang
Published: December 2016

Flowering time is a very important agronomic trait and the development of molecular markers associated with this trait can facilitate crop breeding. CIRCADIAN CLOCK ASSOCIATED 1 (CCA1), a core oscillator component of circadian rhythms that affect metabolic pathways in plants, has been implicated in flowering time control in species of Brassica. CCA1 gene sequences from three Brassica rapa inbred lines, showing either early flowering or late flowering phenotypes, were analyzed and a high level of sequence variation was identified, especially within the fourth intron. Using this information, three PCR primer sets were designed and tested using various inbred lines of B. rapa. The usage of InDel markers was further validated by evaluation of flowering time and high resolution melting (HRM) analysis. Both methods, PCR and HRM, validated the use of newly developed markers. Additional sequence analyses of Brassica plants with diploid (AA, BB, or CC) and allotetraploid genomes further confirmed a large number of sequence polymorphisms in the CCA1 gene, including insertions/deletions in the fourth intron. Our results demonstrated that sequence variations in CCA1 can be used to develop valuable trait-related molecular markers for Brassica crop breeding.
The importance of molecular markers and primer design when characterizing biodiversity from environmental DNA
Authors: Freeland Joanna R.
Published: December 2016

Environmental DNA (eDNA) comprises DNA fragments that have been shed into the environment by organisms, and which can be extracted from environmental samples such as water or soil. Characterization of eDNA can allow researchers to infer the presence or absence of species from a particular site without the need to locate and identify individuals, and therefore may provide an extremely valuable tool for quantifying biodiversity. However, as is often the case with relatively new protocols, methodological challenges remain. A number of earlier reviews have discussed these challenges, but none have provided extensive treatment of the critical decisions surrounding molecular markers and primer development for use in eDNA assays. This review discusses a number of options and approaches that can be used when determining which primers and gene regions are most appropriate for either targeted species detection or metabarcoding macro-organisms from eDNA. The latter represents a new field that is growing rapidly, and which has the potential to revolutionize future assessments of community and ecosystem diversity.
Clinical Vagus Nerve Stimulation Paradigms Induce Pronounced Brain and Body Hypothermia in Rats
Authors: Larsen Lars Emil , Lysebettens Wouter Van , Germonpré Charlotte , Carrette Sofie , Daelemans Sofie , Sprengers Mathieu , Thyrion Lisa , Wadman Wytse Jan , Carrette Evelien , Delbeke Jean , Boon Paul , Vonck Kristl , Raedt Robrecht
Published: December 2016

Vagus nerve stimulation (VNS) is a widely used neuromodulation technique that is currently used or being investigated as therapy for a wide array of human diseases such as epilepsy, depression, Alzheimer’s disease, tinnitus, inflammatory diseases, pain, heart failure and many others. Here, we report a pronounced decrease in brain and core temperature during VNS in freely moving rats. Two hours of rapid cycle VNS (7s on/18s off) decreased brain temperature by around [Formula: see text]C, while standard cycle VNS (30[Formula: see text]s on/300[Formula: see text]s off) was associated with a decrease of around [Formula: see text]C. Rectal temperature similarly decreased by more than [Formula: see text]C during rapid cycle VNS. The hypothermic effect triggered by VNS was further associated with a vasodilation response in the tail, which reflects an active heat release mechanism. Despite previous evidence indicating an important role of the locus coeruleus-noradrenergic system in therapeutic effects of VNS, lesioning this system with the noradrenergic neurotoxin DSP-4 did not attenuate the hypothermic effect. Since body and brain temperature affect most physiological processes, this finding is of substantial importance for interpretation of several previously published VNS studies and for the future direction of research in the field.
Universal resilience patterns in cascading load model: More capacity is not always better
Authors: Wang Jianwei , Wang Xue , Cai Lin , Ni Chengzhang , Xie Wei , Xu Bo
Published: December 2016

We study the problem of universal resilience patterns in complex networks against cascading failures. We revise the classical betweenness method and overcome its limitation of quantifying the load in cascading model. Considering that the generated load by all nodes should be equal to the transported one by all edges in the whole network, we propose a new method to quantify the load on an edge and construct a simple cascading model. By attacking the edge with the highest load, we show that, if the flow between two nodes is transported along the shortest paths between them, then the resilience of some networks against cascading failures inversely decreases with the enhancement of the capacity of every edge, i.e. the more capacity is not always better. We also observe the abnormal fluctuation of the additional load that exceeds the capacity of each edge. By a simple graph, we analyze the propagation of cascading failures step by step, and give a reasonable explanation of the abnormal fluctuation of cascading dynamics.
Lattice Boltzmann simulation of fluid flow and heat transfer in a parallel-plate channel with transverse rectangular cavities
Authors: Mohebbi Rasul , Heidari Hanif
Published: December 2016

The aim of this paper is investigating the forced convection heat transfer in a channel with transverse rectangular cavities using the lattice Boltzmann method (LBM) which is not available in the literature yet. The effects of the Reynolds number (100–400), cavity aspect ratio ([Formula: see text], 0.5, 1.0), distance of cavities from each other ([Formula: see text]) in fixed depth of cavity ([Formula: see text]) on the velocity and temperature profiles are studied. Moreover, the flow patterns such as deflection and re-circulation zone inside the cavities are obtained. The local and averaged Nusselt numbers on the channel walls are achieved. The results show that the channel with cavities achieves heat transfer enhancements relative to the smooth channel. For the constant cavity aspect ratio, the maximum value of averaged Nusselt number in the channel is obtained in the case of [Formula: see text]. Heat transfer to the working fluids increases significantly by increasing the aspect ratio. The existed results are used to ascertain the validity of the numerical code and excellent agreement between results was found.
ARE PRICES STICKY IN LARGE DEVELOPING ECONOMIES? AN EMPIRICAL COMPARISON OF CHINA AND INDIA
Authors: CHONG TERENCE TAI LEUNG , RAFIQ M. S. , ZHU TINGTING JUNI , WU ZHANG
Published: December 2016

By employing the factor augmented vector autoregression (FAVAR) model, this paper compares the role of macroeconomic and sector-specific factors in price movements for China and India, taking into account the features unique to developing economies. We find that fluctuations in the aggregated prices in China are more persistent than the underlying disaggregated prices. Compared to China, prices in India respond more promptly to macroeconomic and monetary policy shocks. We also show that the urban CPI in China responds more sharply than rural CPI when facing sector-specific shocks, while the opposite is valid for India.
Electronic and magnetic properties of monolayer MnS2
Authors: Yue Yunliang
Published: December 2016

First-principles calculations are performed to study the electronic and magnetic properties of monolayer MnS2. Based on the electronic structure, a half-metallic state is predicted for monolayer MnS2. The magnetic moment is 3.0 [Formula: see text] per formula unit, and the main contribution is localized at the transition metal site Mn with a local moment of 3.733 [Formula: see text]. The magnetic anisotropy energy (MAE) is 0.056 meV per formula unit with an easy axis perpendicular to the plane, and it indicates that monolayer MnS2 belongs to the category of Ising magnets. The positive MAE of nanosheets mainly stems from the area around [Formula: see text] in the reciprocal space. To find the microscopic origin, we take the method of the second-order spin orbit coupling. The occupied spin-up dz2 state and the unoccupied spin-down dyz states in the [Formula: see text] point through the [Formula: see text] operator make positive contributions to the MAE.
The influence of bubble populations generated under windy conditions on the blue–green light transmission in the upper ocean: An exploratory approach
Authors: Wang Chengan , Tan Jianyu , Lai Qingzhi
Published: December 2016

The “blue–green window” in the ocean plays an important role in functions such as communication between vessels, underwater target identification, and remote sensing. In this study, the transmission process of blue–green light in the upper ocean is analyzed numerically using the Monte Carlo method. First, the effect of total number of photons on the numerical results is evaluated, and the most favorable number is chosen to ensure accuracy without excessive costs for calculation. Then, the physical and mathematical models are constructed. The rough sea surface is generated under windy conditions and the transmission signals are measured in the far field. Therefore, it can be conceptualized as a 1D slab with a rough boundary surface. Under windy conditions, these bubbles form layers that are horizontally homogeneous and decay exponentially with depth under the influence of gravity. The effects of bubble populations on the process of blue–green light transmission at different wind speeds, wavelengths, angle of incidence and chlorophyll-[Formula: see text] concentrations are studied for both air-incident and water-incident cases. The results of this study indicate that the transmission process of blue–green light is significantly influenced by bubbles under high wind-speed conditions.
Design and Optimization of Differential Ring Oscillator for IR-UWB Applications in 0.18 μm CMOS Technology
Authors: Gargouri Nadia , Issa Dalenda Ben , Sakka Zied , Kachouri Abdennaceur , Samet Mounir
Published: December 2016

This study presents a two-stage ring voltage-controlled oscillator (VCO) for use in impulse-radio ultra-wideband (IR-UWB) applications. A systematic and efficient graphical optimization method was employed to find the optimal dimensions of the VCO which give a best performance. A good agreement was observed between the desired specifications and simulation results with regard to the optimum component size of the VCO circuit. The operation range of the VCO was extended to cover an ultra-wide tuning range of 176.6%. The phase noise was [Formula: see text]107.1[Formula: see text]dBc/Hz at 10[Formula: see text]MHz offset frequency from a carrier frequency of 4[Formula: see text]GHz. The power consumption of VCO was 7.41[Formula: see text]mW from a 1.8[Formula: see text]V supply voltage. A large tuning range, low power, and appropriate phase noise were obtained with the optimum components size obtained through the optimization method.
A Novel High-Speed, Low-Power CNTFET-Based Inexact Full Adder Cell for Image Processing Application of Motion Detector
Authors: Mehrabani Yavar Safaei , Mirzaee Reza Faghih , Zareei Zahra , Daryabari Seyedeh Mohtaram
Published: December 2016

This paper presents a novel inexact full adder based on carbon nanotube field-effect transistors (CNTFET) for approximate computations, which has soared in popularity especially for image processing applications. The proposed design generates the output carry without error. Therefore, the propagation of incorrect value to higher bit positions is avoided. It has the least relative error distance (Relative ED) compared to other approximate full adders reported in the literature. Practical simulations by using MATLAB demonstrate higher peak signal to noise ratio (PSNR) and image quality for motion detector image processing application. HSPICE simulations also confirm the efficiency of the proposed design. Moreover, area occupation is investigated by using electric tool. Power consumption, delay, area and ED are important evaluating factors in this subject. Comparisons are made by a comprehensive parameter (PDAEDP), based on which the new design has 23.8%, 41.5%, 70.5%, 78% and 83.6% higher performance than TGA1, TGA2, AXA1, AXA2 and AXA3, respectively.
An Analytic Method for Estimating the Computation Capacity of Computing Devices
Authors: Ryabko Boris , Rakitskiy Anton
Published: December 2016

A recently suggested method for evaluating computer performance is applied to real processors. The method is based on notion of Computer Capacity, which is determined only by the computer architecture and can be computed theoretically on the design stage. The computer capacity for different Intel and AMD processors is calculated and the results are compared with those of widely recognized benchmarks. The obtained results show that computer capacity is a reasonable estimate of computer performance.
Rule Extraction from Training Data Using Neural Network
Authors: Biswas Saroj Kumar , Chakraborty Manomita , Purkayastha Biswajit , Roy Pinki , Thounaojam Dalton Meitei
Published: December 2016

Data Mining is a powerful technology to help organization to concentrate on most important data by extracting useful information from large database. One of the most commonly used techniques in data mining is Artificial Neural Network due to its high performance in many application domains. Despite many advantages of Artificial Neural Network, one of its main drawbacks is its inherent black box nature which is the main problem of using Artificial Neural Network in data mining. Therefore, this paper proposes a rule extraction algorithm from neural network using classified and misclassified data to convert the black box nature of Artificial Neural Network into a white box. The proposed algorithm is a modification of the existing algorithm, Rule Extraction by Reverse Engineering (RxREN). The proposed algorithm extracts rules from trained neural network for datasets with mixed mode attributes using pedagogical approach. The proposed algorithm uses both classified as well as misclassified data to find out the data ranges of significant attributes in respective classes, which is the innovation of the proposed algorithm. The experimental results clearly show that the performance of the proposed algorithm is superior to existing algorithms.
Mechanics of Collapse of WTC Towers Clarified by Recent Column Buckling Tests of Korol and Sivakumaran
Authors: Le Jia-Liang , Bažant Zdeněk P.
Published: December 2016

The previously formulated model of the gravity-driven collapse of the twin towers of the World Trade Center (WTC) on September 11, 2011 was shown to match all the existing observations, including the video record of the crush-down motion of the top part of tower during the first few seconds, the seismically recorded duration of collapse, the size distribution of particles caused by impact comminution of concrete floor slabs, the loud booms due to near-sonic lateral ejection velocity of air and dust, and precedence of the crush-down collapse mode before the crush-up. Nevertheless, different degrees of ductility, fracturing and end support flexibility of WTC columns could lead to an equally good match of these observations and remained uncertain, due to lack of test data. Recently, Korol and Sivakumaran reported valuable experiments that allow clarifying this uncertainty. They revealed that, under the simplifying assumptions of rigid end supports and unlimited ductility (or no fracturing) of unheated columns, the energy dissipation of the WTC columns would have been at maximum 3.5-times as large as that calculated by the plastic hinge mechanism normally considered for small-deflection buckling. This increase would still allow close match of all the aforementioned observations except for the first two seconds of the video. The proper conclusion from Korol and Sivakumaran’s tests, based on close matching of the video record, is that the fracturing of unheated columns and the flexibility of their end restraints must have significantly reduced the energy dissipation in columns calculated under the assumptions of no fracture and no end restraint flexibility.
Adically finite chain complexes
Authors: Sather-Wagstaff Sean , Wicklein Richard
Published: December 2016

We investigate the similarities between adic finiteness and homological finiteness for chain complexes over a commutative Noetherian ring. In particular, we extend the isomorphism properties of certain natural morphisms from homologically finite complexes to adically finite complexes. We do the same for characterizations of certain homological dimensions. In addition, we study transfer of adic finiteness along ring homomorphisms, all with a view toward subsequent applications.
NUMERICAL STUDY OF SLIP EFFECTS ON UNSTEADY ASYMMETRIC BIOCONVECTIVE NANOFLUID FLOW IN A POROUS MICROCHANNEL WITH AN EXPANDING/CONTRACTING UPPER WALL USING BUONGIORNO’S MODEL
Authors: BÉG O. ANWAR , BASIR Md. FAISAL Md. , UDDIN M. J. , ISMAIL A. I. Md.
Published: December 2016

In this paper, the unsteady fully developed forced convective flow of viscous incompressible biofluid that contains both nanoparticles and gyrotactic microorganisms in a horizontal micro-channel is studied. Buongiorno’s model is employed. The upper channel wall is either expanding or contracting and permeable and the lower wall is static and impermeable. The plate separation is therefore a function of time. Velocity, temperature, nanoparticle species (mass) and motile microorganism slip effects are taken into account at the upper wall. By using the appropriate similarity transformation for the velocity, temperature, nanoparticle volume fraction and motile microorganism density, the governing partial differential conservation equations are reduced to a set of similarity ordinary differential equations. These equations under prescribed boundary conditions are solved numerically using the Runge–Kutta–Fehlberg fourth-fifth-order numerical quadrature in the MAPLE symbolic software. Excellent agreement between the present computations and solutions available in the literature (for special cases) is achieved. The key thermofluid parameters emerging are identified as Reynolds number, wall expansion ratio, Prandtl number, Brownian motion parameter, thermophoresis parameter, Lewis number, bioconvection Lewis number and bioconvection Péclet number. The influence of all these parameters on flow velocity, temperature, nanoparticle volume fraction (concentration) and motile microorganism density function is elaborated. Furthermore, graphical solutions are included for skin friction, wall heat transfer rate, nanoparticle mass transfer rate and microorganism transfer rate. Increasing expansion ratio is observed to enhance temperatures and motile microorganism density. Both nanoparticle volume fraction and microorganism increases with an increase in momentum slip. The dimensionless temperature and microorganism increases as wall expansion increases. Applications of the study arise in advanced nanomechanical bioconvection energy conversion devices, bio-nano-coolant deployment systems, etc.
Boosting non-graph matching feature-based face recognition with a multi-stage matching strategy
Authors: Chen Xianming , Zhang Chaoyang , Zhou Zhaoxian
Published: December 2016

In this paper, a multi-stage matching strategy is proposed to boost the performance of a non-graph matching feature-based face recognition. As the gallery size increases, the problem of recognition degradation gradually arises, due to the fact that the correct matching of feature points becomes more and more difficult. Other than only one round of matching in traditional methods, the multi-stage matching strategy determines the recognition result step by step. Instead of finding the best one matching, each step picks out a small portion of the training candidates and removes the others. The behavior of picking and removing repeats until the number of remaining candidates is small enough to produce the final result. Two multi-stage matching algorithms, n-ary elimination and divide and conquer, are introduced into the non-graph matching feature-based method from the perspectives of global and local, respectively. The experimental result shows that with the multi-stage matching strategy, the recognition accuracy of the non-graph matching feature-based method is evidently boosted. Moreover, the improvement level also increases with the gallery size.
Computations of Singular Stresses Along Three-Dimensional Corner Fronts by a Super Singular Element Method
Authors: Ping Xuecheng , Chen Mengcheng , Zhu Wei , Xiao Yihua , Wu Weixing
Published: December 2016

In order to consider corner configurations with straight corner fronts in three-dimensional (3D) solids, a super polygonal prismatic element containing a straight corner front is established by using the numerical eigensolutions of singular stress fields and the Hellinger–Reissner variational principle. Singular stresses near the corner front subject to far-field boundary conditions can be obtained by incorporating the super singular element with conventional 3D brick elements. The numerical studies are conducted to demonstrate the simplicity of the proposed technique in handling fracture problems of 3D corner configurations and cracks. The usage of the super singular element can avoid mesh refinement near the corner front domain that is necessary for conventional and enriched finite element methods, and lead to high accuracy and fast convergence. Compared with the conventional finite element methods and existing analytical methods, the present method is more suitable for dealing with complicated problems of stress singularity in elasticity including multiple defects.
Generalized Robertson–Walker spacetimes — A survey
Authors: Mantica Carlo Alberto , Molinari Luca Guido
Published: December 2016

Generalized Robertson–Walker spacetimes extend the notion of Robertson–Walker spacetimes, by allowing for spatial non-homogeneity. A survey is presented, with main focus on Chen's characterization in terms of a timelike concircular vector. Together with their most important properties, some new results are presented.
The derivative and tangent operators of a motion in Lorentzian space
Authors: Durmaz Olgun , Aktaş Buşra , Gündoğan Hali̇t
Published: December 2016

In this paper, by using Lorentzian matrix multiplication, [Formula: see text]-Tangent operator is obtained in Lorentzian space. The [Formula: see text]-Tangent operators related with planar, spherical and spatial motion are computed via special matrix groups. [Formula: see text]-Tangent operators are related to vectors. Some illustrative examples for applications of [Formula: see text]-Tangent operators are also presented.
Bose description of the generalized Pauli spin operators and para super symmetry
Authors: Chung Won Sang
Published: December 2016

In this paper, the generalized fermion algebra is introduced so as to have the [Formula: see text]-dimensional Fock space. The generalized Pauli spin matrices of order [Formula: see text] are introduced by identifying these matrices with the step operators of the generalized fermion algebra. From the [Formula: see text]-graded parity relation [Formula: see text] generalized Pauli matrices are obtained. Finally, the para super symmetry (SUSY) is realized in terms of these matrices and ordinary bosonic operators.
Dissipative universe-inflation with soft singularity
Authors: Brevik Iver , Timoshkin Alexander V.
Published: December 2016

We investigate the early-time accelerated universe after the Big Bang. We pay attention to the dissipative properties of the inflationary universe in the presence of a soft type singularity, making use of the parameters of the generalized equation of state of the fluid. Flat Friedmann–Robertson–Walker metric is being used. We consider cosmological models leading to the so-called type IV singular inflation. Our obtained theoretical results are compared with observational data from the Planck satellite. The theoretical predictions for the spectral index turn out to be in agreement with the data, while for the scalar-to-tensor ratio, there are minor deviations.
The minimal decay regularity of smooth solutions to the Euler–Maxwell two-fluid system
Authors: Xu Jiang , Kawashima Shuichi
Published: December 2016

The compressible Euler–Maxwell two-fluid system arises in the modeling of magnetized plasmas. We first design crucial energy functionals to capture its dissipative structure, which is relatively weaker in comparison with the one-fluid case in the whole space [Formula: see text], due to the nonlinear coupling and cancelation between electrons and ions. Furthermore, with the aid of [Formula: see text]-[Formula: see text]-[Formula: see text] time-decay estimates, we obtain the [Formula: see text]-[Formula: see text] decay rate with the critical regularity ([Formula: see text]) for the global-in-time existence of smooth solutions, which solves the decay problem left open in [Y. J. Peng, Global existence and long-time behavior of smooth solutions of two-fluid Euler–Maxwell equations, Ann. IHP Anal. Non Linéaire 29 (2012) 737–759].
A vector field method for non-trapping, radiating spacetimes
Authors: Oliver Jesús
Published: December 2016

We study the global decay properties of solutions to the linear wave equation in 1+3 dimensions on time-dependent, weakly asymptotically flat spacetimes. Assuming non-trapping of null geodesics and a local energy decay estimate, we prove that sufficiently regular solutions to this equation have bounded conformal energy. As an application we also show a conformal energy estimate with vector fields applied to the solution as well as a global [Formula: see text] decay bound in terms of a weighted norm on initial data. For solutions to the wave equation in these dynamical backgrounds, our results reduce the problem of establishing the classical pointwise decay rate [Formula: see text] in the interior and [Formula: see text] along outgoing null cones to simply proving that local energy decay holds.
Scattering operator for the one-dimensional Dirac equation with power nonlinearity
Authors: Hayashi Nakao , Sasaki Hironobu
Published: December 2016

We consider the nonlinear Dirac equation with a power nonlinearity [Formula: see text] where [Formula: see text], [Formula: see text]. We prove the existence of the scattering operator in the neighborhood of the origin of the weighted Sobolev space [Formula: see text], where [Formula: see text].