bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Processing Conditions on the Microstructure and Electromechanical Response of PVDF TrFE CTFE Terpolymers
Authors: Sigamani Nirmal Shankar , Ahmed Saad , Ounaies Zoubeida
Published: December 2014

Effect of annealing time on the micro structure and electromechanical properties PVDF TrFE CTFE terpolymer with 7.8 mol % CTFE was investigated to better understand structure-property relationships in these polymers. DSC results show that the 9 hr-annealing time gives the maximum enthalpy of melting which suggests the crystallinity of the polymer is increased. WAXS results show that annealing increases the proportion of the γ-phase with the ratio of the intensity of γ-phase to α-phase increases with more annealing time. Dielectric spectroscopic study of 9hr-annealed film also suggests that the film shows complete relaxor ferroelectric behavior with a maximum electrostrictive strain up to 4.4 % compared to 4.1 % for the 2.5 hr-annealed film. Finally, annealing time higher than 9 hrs result in a decrease in the electrostrictive strain.
Microstructure Properties and Strengthening Mechanisms of the AS4-3501-6 Polymeric Resin With Embedded Terfenol-D Particles
Authors: Alexander Jamel H. , Myers Oliver J.
Published: December 2014

Polymeric composite laminates play a vital role in the fabrication of strong, lightweight materials. Composites also play a critical role in the aerospace and automotive industries. They are the very things that protect us from harsh environments. Due to widespread usage, it is important to understand how these materials age and perform over time. The advantages of polymeric composites are high rigidity, high strength to weight ratio, corrosion resistance, high fatigue strength, low thermal expansion, and manufacturability. The advantages of polymeric composite parts in machines and vehicles are low mass, high speed of operation, excellent fatigue resistance, quiet running due to shock absorption, easy installment and demounting, low maintenance cost, low energy costs during production and life cycle. Despite the advantages, there are concerns regarding the long-term durability of these composites especially when it comes to performances under critical and varying conditions. Since Terfenol-D, a magnetostrictive material will be placed in these polymeric composites for structural health monitoring, it is imperative to understand the microstructure of the particles and their net effect on the resin, e.g. distortions, volume fraction, and induced strain. Terfenol-D (Tb1−xDyxFe2) is of the cubic laves phase structure in which there is less plastic deformation which in turn makes the particles hard and brittle.
Shape Memory Polymers: Viscoelastic Thermomechanical Constitutive Modeling
Authors: Balogun Olaniyi A. , Mo Changki
Published: December 2014

Shape memory polymers (SMPs) are known to change their elastic stiffness as they respond to change in induced stimulus such as temperature. Under appropriate loading and pre-deformation, a shape memory effect can be captured as the stimulus change. From the nature of polymers, the pre-deformation can tend to be large and can in turn be memorized by SMPs. Due to this characteristic of SMPs, it makes a great candidate for morphing structures. To analyze complex structures a simple but yet practical constitutive model needs to be developed for commercial engineering application. In this paper, a thermomechanical constitutive model is proposed making use of the standard linear viscoelastic model. The total strain during the shape memorization process is defined by mechanical, thermal and storage strains. The rheological model defined is an elastic element in parallel with a Maxwell element, which in turn are both in series with storage and thermal element. Inclusion of a storage strain within the model reveals the internal strain storage mechanism as the temperature of the material drops. Similar work done in the past requires material parameters that can be arduous to determine in the laboratory. This model proposes a simplified approximate material parameter called a binding factor which accounts for the polymer’s molecular architecture and morphology as the temperature changes. Finally, the model is applied to a four step shape memorization and stress-free recovery process. For this study, the four steps considered are a) Pre-loading of the material at high temperature b) Constant strain fixity c) unconstrained relaxation at low temperature d) unconstrained free strain recovery. The developed model is validated by comparing the predictions to experimental results in literature.
The Experimental Validation of Pseudoelastic Shape Memory Sheet Elements in Tooling Applications
Authors: Theiß Ralf , Nürnberg Tobias , Czechowicz Alexander
Published: December 2014

Shape memory alloys (SMA) are capable to remember a previously programmed form even after strong deformation. The reversible deformation of pseudoelastic SMA takes place on the basis of stress-induced martensitic phase transformation. These alloys are also interesting for elastic spring and damping elements, making their use in a variety of different machining and tool applications conceivable. Examples are elastic spring elements in forceps or damping elements in the field of sawing applications. The use of sheet like pseudoelsatic elements is of particular relevance for applications in handheld- and machining-tools. High elastic deformability, the damping properties and the potential of setting a horizontal spring characteristic curve in SMA elements come with problems such as strong temperature dependence of the spring and damping characteristics, possible limitations on the durability due to aging effects in cyclically occurring loads. Therefore, it requires a more extensive characterization and validation of sheet-shaped NiTi spring and damping elements. Hence different sheet-shaped SMA elements are analyzed in this publication due to different bends and thicknesses as well as different heat treatments for programming shapes into the sheets. Prepared sheets are characterized, especially cycle dependent force to displacement and damping properties. The publication shows experimental results of this analysis for various SMA sheets and potential industrial applications in the field of machine tools.
Artificial Hair Sensors: Electro-Mechanical Characterization
Authors: Phillips David M. , Slinker Keith A. , Ray Cody W. , Hagen Benjamin J. , Baur Jeffery W. , Dickinson Benjamin T. , Reich Gregory W.
Published: December 2014

Performance demands of future unmanned air vehicles will require rapid autonomous responses to changes in environment. Towards this goal, we expect that the next generation flight control systems will include advanced sensors beyond the contemporary array. One promising scenario correlates measurements of flow footprints over aircraft surfaces with aerodynamic data to aid navigation and feedback control algorithms. As a sensor for this concept, we construct artificial hair sensors (AHSs) based on glass microfibers enveloped in an annular, radially-aligned piezoresistive carbon nanotube (CNT) forest to measure air flow in boundary layers. This study includes an analysis of the sensitivity based on laboratory scale electromechanical testing.

The sensors in this work utilize nine micron diameter S2 glass fibers as the sensing mechanism for coupling to boundary layer air flows. The annular CNT forest resides in a fused silica microcapillary with electrodes at the entrance. The sensor electrical transduction mechanism relies on the resistance change of the CNT forest due to changes in both the bulk and contact resistance as a function of mechanical loading on the fiber. For the electromechanical analysis, the sensors are controllably loaded to measure both the force and moment acting at the base of the hair and the resulting deflection of the CNT forest inside of the microcapillary is measured to estimate the stress on the forest and the pressure between the forest and the electrode. The electrical responses of the sensors are compared to the mechanical state of the CNT forest. This work represents the development of a characterization tool to better understand and control the response of CNT based AHSs.
Investigating the Feasibility of Tuning the Natural Frequency of an Electromagnetically-Transduced Energy Harvester Using Passively-Controlled Inductance
Authors: Yamamoto Brennan E. , Trimble A. Zachary
Published: December 2014

As the required power for wireless, low-power sensor systems continues to decrease, the feasibility of a fully self-sustaining, onboard power supply, has increased interest in the field of vibration energy harvesting — where ambient kinetic energy is scavenged from the surrounding environment. Current literature has produced a number of harvesting techniques and transduction methods; however, they are all fundamentally similar in that, the harmonic excitation frequency must fall within the resonant bandwidth frequency of the harvesting mechanism to maintain acceptable energy output. The purpose of this research is to investigate the potential for natural frequency tuning by means of passive electrical components, that is, using an imposed electrical inductance to adjust the equivalent stiffness, and resulting resonant frequency of a vibration energy harvester. In past literature, it was concluded that an “active” frequency tuning mechanism would be infeasible, as the power required by an equivalent “stiffening transducer” would require more power to maintain the system at resonance, than the system would actually produce as a result of maintaining resonance, i.e., a net energy loss (Roundy and Zhang 2005). It is believed that the model used in this conclusion can be improved by directly modeling changes in system stiffness as an equivalent mechanical spring, instead of an external inertial loading. Due to the conservative nature of the harmonic spring, the compliance of a harvesting mechanism can be theoretically altered without energy losses, whether the actuation is applied using “active” or “passive” means. This revised model departs from the traditional, base excitation model in most vibration energy harvesting systems, and includes additional stiffness, and damping elements, representative of induced mechanical spring, and related losses. We can validate the feasibility of this technique, if it can be shown that the natural frequency of an energy harvester can be altered, and still maintain energy output similar to its “untuned” natural frequency. If feasible, this tuning method would provide a viable alternative to other bandwidth-increasing techniques in literature, e.g., wideband harvesting, bandwidth normalizing, high-damping, etc. In this research, a change in natural frequency of the experimental energy harvesting system of 0.5 Hz was demonstrated, indicating that adjusting the natural frequency of a vibration energy harvesting system is possible; however, there are many new challenges associated with the revised energy harvesting model, related to the new introduced losses to the system, as well as impedance matching between the mechanical and electrical domains. Further research is required to better quantitatively characterize the relationship between natural frequency shift, and imposed electrical inductance.
A New Method for Coupling Transient Network Models and Stationary Finite-Element Models
Authors: Ziske Johannes , Neubert Holger
Published: December 2014

In many cases, the accuracy of transient multi-domain network models can be improved by coupling to distributed models, e.g. finite-element (FE) models, which compute for specific element parameters, flow or potential variables of the network model. Two opposing methods are known. The first is direct simulator coupling. It requires solving of the distributed model in each iteration step of the network model simulation. The second is the uncoupled calculation of characteristic maps from stationary distributed models which are then used in the transient model in form of look-up tables. Since the course of the base parameters of the characteristic maps is unknown before the transient simulation runs the stationary distributed model has to be solved for all grid points of the spanned parameter space. Both methods lead to an inefficient high number of necessary calculations of the distributed model which usually determines the computing costs. We present a new approach which significantly reduces the number of necessary computations. The main idea is combining both methods and successively computing grid points of the characteristic maps depending on the current need while solving the transient model. This is demonstrated for the example of an electromagnetic actuator. In the presented example, the number of FE model calculations was reduced to a tenth.
Cantilever Beam Metamaterial Structure With Periodic Piezoelectric Arrays With High-Order Resonant Circuit Shunts for Vibration Control
Authors: Zhou Wanlu , Wu You , Zuo Lei
Published: December 2014

Metamaterial structures of beam or plate with periodic piezoelectric arrays have attracted more and more attention in recent years, which are conventionally designed for waveguide and/or wave propagation attenuation. The metamaterial structure with periodic piezoelectric shunts has also been explored for vibration control. R shunt and R-L shunt are traditionally adopted for the shunt circuit. An innovative type of high-order resonant circuit shunt is proposed and investigated for the periodic piezoelectric metamaterial in this paper. The introduction of an external inductor in the R-L shunt forms a resonance with the piezoelectric capacitance, which has the effect of reducing mechanical vibration at the resonant frequency of LC branch, with a certain bandwidth. The design of high-order resonant circuit shunt is introducing one more resonance around the resonant frequency, which is expected to broaden the bandwidth of the vibration attenuation. Finite element modeling of the metamaterial structure with periodic piezoelectric transducers is established. The method of obtaining the attenuation constant is also presented. Simulations have been conducted on comparing the vibration control performances among piezoelectric arrays with R shunt, R-L shunt, and the proposed high-order resonant circuit shunt. The simulation results illustrate that the proposed metamaterial structure with high-order resonant circuit shunts has broader vibration attenuation bandwidth. However, there is a tradeoff between the vibration attenuation amplitude and the vibration attenuation bandwidth, that is, although the high-order resonant circuit shunt has broader vibration reduction bandwidth, it cannot attenuate in larger amplitude.
Inelastic effects in low-energy electron reflectivity of two-dimensional materials
Authors: Gao Qin , Mende Patrick C. , Widom Michael , Feenstra Randall M.
Published: December 2014

A simple method is proposed for inclusion of inelastic effects (electron absorption) in computations of low-energy electron reflectivity (LEER) spectra. The theoretical spectra are formulated by matching of electron wavefunctions obtained from first-principles computations in a repeated vacuum–slab–vacuum geometry. Inelastic effects are included by allowing these states to decay in time in accordance with an imaginary term in the potential of the slab, and by mixing of the slab states in accordance with the same type of distribution as occurs in a free-electron model. LEER spectra are computed for various two-dimensional materials, including free-standing multilayer graphene, graphene on copper substrates, and hexagonal boron nitride on cobalt substrates.
Build-up and two-step relaxation of internal stress in jammed suspensions
Authors: Mohan Lavanya , Cloitre Michel , Bonnecaze Roger T.
Published: December 2014

We perform experiments on jammed suspensions of microgels with different constituent properties to determine their stress relaxation behavior on flow cessation. We observe that the stress relaxes through a two-step process: A rapid initial relaxation where internal stresses are trapped followed by a much slower decay. Trapped internal stresses are related to the solvent viscosity, particle elasticity, and volume fraction through a universal scaling. The second slower relaxation of the internal stress is characterized by a single exponential decay, which is independent of the preshear stress and relatively insensitive to the material properties of the microgel suspension. Particle-scale simulations are used to understand the microscopic mechanisms which drive the amplitude and the kinetics of the stress relaxation as well as the local particle dynamics in each regime. The rapid initial relaxation occurs through ballistic particle motion, where the number of contacts and average compression return to their static values but the asymmetry of the pair distribution function remains as a signature of the internal stress.
Smoking is associated with mosaic loss of chromosome Y
Authors: Dumanski Jan P. , Rasi Chiara , Lönn Mikael , Davies Hanna , Ingelsson Martin , Giedraitis Vilmantas , Lannfelt Lars , Magnusson Patrik K. E. , Lindgren Cecilia M. , Morris Andrew P. , Cesarini David , Johannesson Magnus , Tiensuu Janson Eva , Lind Lars , Pedersen Nancy L. , Ingelsson Erik , Forsberg Lars A.
Published: December 2014

Men beware, when smoke gets in your Y's

The relationship between tobacco smoking and elevated cancer risk has been recognized for 60 years. Yet what smoking does to our genetic material is still not fully understood. New work suggests that men should be particularly concerned. In a study of over 6000 men, Dumanski
et al.
find that men who smoke are more than three times as likely as nonsmokers to show loss of the Y chromosome in their blood cells. Whether this is a causal factor in cancer development or simply a marker of more consequential damage on other chromosomes could not be deduced from the study.

Science
, this issue p.
81
Draft Genome Sequences of Antibiotic-Resistant Commensal Escherichia coli
Authors: Garrett Meghan , Parker Jennifer , Stephens Craig M.
Published: December 2014

Antimicrobial resistance is a significant public health issue. We report here the draft genome sequences of three drug-resistant strains of commensal
Escherichia coli
isolated from a single healthy college student. Each strain has a distinct genome, but two of the three contain an identical large plasmid with multiple resistance genes.
Complete Genome Sequence of the Embu Virus Strain SPAn880
Authors: Ibrahim M. Sofi , Antwerpen Markus , Georgi Enrico , Vette Philipp , Zoeller Gudrun , Meyer Hermann
Published: December 2014

We report the complete genome sequence of the Embu virus. The genome consists of 185,139 bp and is nearly identical to that of the Cotia virus. This is the first report on the Embu virus genome sequence, which has been considered an unclassified poxvirus until now.
Complete Genome Sequence of Haemophilus influenzae Strain 375 from the Middle Ear of a Pediatric Patient with Otitis Media
Authors: Mell Joshua Chang , Sinha Sunita , Balashov Sergey , Viadas Cristina , Grassa Christopher J. , Ehrlich Garth D. , Nislow Corey , Redfield Rosemary J. , Garmendia Junkal
Published: December 2014

Originally isolated from a pediatric patient with otitis media,
Haemophilus influenzae
strain 375 (Hi375) has been extensively studied as a model system for intracellular invasion of airway epithelial cells and other pathogenesis traits. Here, we report its complete genome sequence and methylome.
Draft Genome Sequence of Bacillus subtilis GXA-28, a Thermophilic Strain with High Productivity of Poly-γ-Glutamic Acid
Authors: Zeng Wei , Chen Guiguang , Tang Zhen , Wu Hao , Shu Lin , Liang Zhiqun
Published: December 2014

Bacillus subtilis
GXA-28 is a thermophilic strain that can produce high yield and high molecular weight of poly-γ-glutamic acid under high temperature. Here, we report the draft genome sequence of this strain, which may provide the genomic basis for the high productivity of poly-γ-glutamic acid.
Lactobacillus reuteriDSM 17938 for managing infant colic: protocol for an individual participant data meta-analysis
Authors: Sung Valerie , Cabana Michael D , D'Amico Frank , Deshpande Girish , Dupont Christophe , Indrio Flavia , Mentula Silja , Partty Anna , Savino Francesco , Szajewska Hania , Tancredi Daniel
Published: December 2014

Introduction

Infant colic, or excessive crying of unknown cause in infants less than 3 months old, is common and burdensome. Its aetiology is undetermined, and consensus on its management is still lacking. Recent studies suggest a possible link between infant colic and gut microbiota, indicating probiotics to be a promising treatment. However, only a few strains have been tested, and results from randomised controlled trials are conflicting. It is important to clarify whether probiotics are effective for treating infant colic in general, and to identify whether certain subgroups of infants with colic would benefit from particular strains of probiotics.

Methods and analysis

Through an individual participant data meta-analysis (IPDMA), we aim to identify whether the probioticLactobacillus reuteriDSM 17938 is effective in the management of infant colic, and to clarify whether its effects differ according to feeding method (breast vs formula vs combined), proton pump inhibitor exposure, and antibiotic exposure. The primary outcomes are infant crying duration and treatment success (at least 50% reduction in crying time from baseline) at 21 days postintervention. Individual participant data from all studies will be modelled simultaneously in multilevel generalised linear mixed-effects regression models to account for the nesting of participants within studies. Subgroup analyses of participant-level and intervention-level characteristics will be undertaken on the primary outcomes to assess if the intervention effect differs between certain groups of infants.

Ethics and dissemination

Approved by the Royal Children's Hospital Human Research Ethics Committee (HREC 34081). Results will be reported in a peer-reviewed journal in 2015.

Trial registration number

PROSPERO CRD42014013210.
Ten‐minute chat
Authors: Wedderburn Pete
Published: December 2014

Pete Wedderburn is a partner in a four‐vet companion animal practice near Dublin. He spends half of his working life in the media, with weekly veterinary features on Irish breakfast television and local radio stations, as well as working in print journalism.
Analysis of buried pipelines subjected to ground surface settlement and heave
Authors: Kouretzis George P. , Karamitros Dimitrios K. , Sloan Scott W.
Published: December 2014

This paper presents an analytical methodology for the calculation of internal forces and strains developing in continuous buried pipelines that cross geotechnically problematic areas and are susceptible to permanent ground surface settlement or heave. Material nonlinearity effects are introduced in the solution via an iterative procedure, while taking into account the effect of pipeline elongation on its response. The use of a versatile bilinear expression to describe the stress–strain response of the pipeline material renders the method appropriate for steel, high-density polyethylene (HDPE), concrete, and cast iron pipelines alike. Comparison of the analytical results against those from benchmark finite element analyses highlights the effectiveness of the simplified analysis. The method is a potential alternative to elaborate three-dimensional nonlinear numerical analyses that are often used in pipeline design practice, and offers ease-of-use with no expense in accuracy, at least for problems involving simple pipeline geometries.
Nonperturbative dynamics of reheating after inflation: A review
Authors: Amin Mustafa A. , Hertzberg Mark P. , Kaiser David I. , Karouby Johanna
Published: December 2014

Our understanding of the state of the universe between the end of inflation and big bang nucleosynthesis (BBN) is incomplete. The dynamics at the end of inflation are rich and a potential source of observational signatures. Reheating, the energy transfer between the inflaton and Standard Model fields (possibly through intermediaries) and their subsequent thermalization, can provide clues to how inflation fits in with known high-energy physics. We provide an overview of our current understanding of the nonperturbative, nonlinear dynamics at the end of inflation, some salient features of realistic particle physics models of reheating, and how the universe reaches a thermal state before BBN. In addition, we review the analytical and numerical tools available in the literature to study preheating and reheating and discuss potential observational signatures from this fascinating era.
Dense elements characterization of quasi-complemented Almost Distributive Lattices
Authors: Rao G. C. , Nanaji Rao G. , Lakshmana A.
Published: December 2014

The properties of the set D of dense elements of an ADL are studied. The filter congruence θD generated by D in quasi-complemented ADLs is characterized. Quasi-complemented ADLs is characterized in terms of dense elements. A necessary and sufficient condition for a quasi-complemented ADLs to become a Boolean algebra is established.
Sandwich results for analytic functions involving with iterations of the Owa–Srivastava operator and its combination
Authors: Soren Madan Mohan
Published: December 2014

In this paper, we investigate some strong differential subordination and strong differential superordination results for analytic functions, which involving the iterations of the Owa–Srivastava operator and its combination. Some new sandwich type results are also obtained.
Facilitating Adoption of Services with Positive Externalities via Subsidies
Authors: Weber Steven , Guérin Roch
Published: December 2014

The paper investigates adoption of network services whose value incorporates three key features, namely, heterogeneity in user service afinity, a positive externality, and a cost. Positive externalities often result in a \chicken and egg" problem where early adopters can see a cost that exceeds the service's (low) initial value. In this paper we study sub- sidies as a means to \reach the knee" and push adoption higher (from zero to one). We focus on the simplest of sub-sidies, namely, a fixed subsidy over a given period of time, and are able to obtain expressions for quantities of natural interest, e.g., the minimum subsidy required, the minimum subsidy duration, and the total subsidy cost. Interestingly, the expressions reveal conditions under which the optimal subsidy is neither the lowest nor applied for the shortest duration. The findings help develop guidelines for effective subsidies to promote the adoption of network services.
Minimizing Energy Consumption of FatTree Data Center Networks
Authors: Yi Qing , Singh Suresh
Published: December 2014

Many data centers are built using a fat-tree network topology because of its high bisection bandwidth. Therefore thereis a need to develop analytical models for the energy behavior of fat-tree networks and examine strategies to reduce energy consumption. The most effective strategy is to power off entire switches, if possible. In this paper, we derive formulas for the minimum number of active switches needed in a fat-tree data center network for arbitrary types of loading. We also derive expressions for the expected traffic loss when these networks are overloaded with external (Internet) traffic. Results of detailed simulations conducted using well-known traffic models for data center networks [4] closely match our derived formulas. We show that a fat-tree network incurs significant energy cost even when very lightly loaded. In order to further reduce energy consumption, we consolidate traffic into fewer switches and derive expressions for energy cost versus load assuming traffic consolidation and show linear scaling. Finally, we observe that traffic patterns have a significant impact on energy consumption and this fact is evident in the analytical formulas.
Central administration of nicotine suppresses tracheobronchial cough in anesthetized cats
Authors: Poliacek I. , Rose M. J. , Pitts T. E. , Mortensen A. , Corrie L. W. , Davenport P. W. , Bolser D. C.
Published: December 2014

We tested the hypothesis that nicotine, which acts peripherally to promote coughing, might inhibit reflex cough at a central site. Nicotine was administered via the vertebral artery [intra-arterial (ia)] to the brain stem circulation and by microinjections into a restricted area of the caudal ventral respiratory column in 33 pentobarbital anesthetized, spontaneously breathing cats. The number of coughs induced by mechanical stimulation of the tracheobronchial airways; amplitudes of the diaphragm, abdominal muscle, and laryngeal muscles EMGs; and several temporal characteristics of cough were analyzed after administration of nicotine and compared with those during control and recovery period. (−)Nicotine (ia) reduced cough number, cough expiratory efforts, blood pressure, and heart rate in a dose-dependent manner. (−)Nicotine did not alter temporal characteristics of the cough motor pattern. Pretreatment with mecamylamine prevented the effect of (−)nicotine on blood pressure and heart rate, but did not block the antitussive action of this drug. (+)Nicotine was less potent than (−)nicotine for inhibition of cough. Microinjections of (−)nicotine into the caudal ventral respiratory column produced similar inhibitory effects on cough as administration of this isomer by the ia route. Mecamylamine microinjected in the region just before nicotine did not significantly reduce the cough suppressant effect of nicotine. Nicotinic acetylcholine receptors significantly modulate functions of brain stem and in particular caudal ventral respiratory column neurons involved in expression of the tracheobronchial cough reflex by a mecamylamine-insensitive mechanism.
A frequency-resolved mutual information rate and its application to neural systems
Authors: Bernardi Davide , Lindner Benjamin
Published: December 2014

The encoding and processing of time-dependent signals into sequences of action potentials of sensory neurons is still a challenging theoretical problem. Although, with some effort, it is possible to quantify the flow of information in the model-free framework of Shannon's information theory, this yields just a single number, the mutual information rate. This rate does not indicate which aspects of the stimulus are encoded. Several studies have identified mechanisms at the cellular and network level leading to low- or high-pass filtering of information, i.e., the selective coding of slow or fast stimulus components. However, these findings rely on an approximation, specifically, on the qualitative behavior of the coherence function, an approximate frequency-resolved measure of information flow, whose quality is generally unknown. Here, we develop an assumption-free method to measure a frequency-resolved information rate about a time-dependent Gaussian stimulus. We demonstrate its application for three paradigmatic descriptions of neural firing: an inhomogeneous Poisson process that carries a signal in its instantaneous firing rate; an integrator neuron (stochastic integrate-and-fire model) driven by a time-dependent stimulus; and the synchronous spikes fired by two commonly driven integrator neurons. In agreement with previous coherence-based estimates, we find that Poisson and integrate-and-fire neurons are broadband and low-pass filters of information, respectively. The band-pass information filtering observed in the coherence of synchronous spikes is confirmed by our frequency-resolved information measure in some but not all parameter configurations. Our results also explicitly show how the response-response coherence can fail as an upper bound on the information rate.
Distance Degree Regular Graphs and Distance Degree Injective Graphs: An Overview
Authors: Huilgol Medha Itagi
Published: December 2014

The distance d(v,u) from a vertex v of G to a vertex u is the length of shortest v to u path. The eccentricity ev of v is the distance to a farthest vertex from v. If d(v,u) = e(v), (u ≠ v), we say that u is an eccentric vertex of v. The radius rad(G) is the minimum eccentricity of the vertices, whereas the diameter diam(G) is the maximum eccentricity. A vertex v is a central vertex if e(v) = rad(G), and a vertex is a peripheral vertex if e(v)  = diam(G). A graph is self-centered if every vertex has the same eccentricity; that is, rad(G) = diam(G). The distance degree sequence (dds) of a vertex v in a graph G = (V, E) is a list of the number of vertices at distance 1, 2, ... . , e(v) in that order, where e(v) denotes the eccentricity of v in G. Thus, the sequence (di0,di1,di2,  …,  dij,…) is the distance degree sequence of the vertex vi in G where dij denotes the number of vertices at distance j from vi. The concept of distance degree regular (DDR) graphs was introduced by Bloom et al., as the graphs for which all vertices have the same distance degree sequence. By definition, a DDR graph must be a regular graph, but a regular graph may not be DDR. A graph is distance degree injective (DDI) graph if no two vertices have the same distance degree sequence. DDI graphs are highly irregular, in comparison with the DDR graphs. In this paper we present an exhaustive review of the two concepts of DDR and DDI graphs. The paper starts with an insight into all distance related sequences and their applications. All the related open problems are listed.
Anion Gap Toxicity in Alloxan Induced Type 2 Diabetic Rats Treated with Antidiabetic Noncytotoxic Bioactive Compounds of Ethanolic Extract ofMoringa oleifera
Authors: Omabe Maxwell , Nwudele Chibueze , Omabe Kenneth Nwobini , Okorocha Albert Egwu
Published: December 2014

Moringa oleifera(MO) is used for a number of therapeutic purposes. This raises the question of safety and possible toxicity. The objective of the study was to ascertain the safety and possible metabolic toxicity in comparison with metformin, a known drug associated with acidosis. Animals confirmed with diabetes were grouped into 2 groups. The control group only received oral dose of PBS while the test group was treated with ethanolic extract of MO orally twice daily for 5-6 days. Data showed that the extract significantly lowered glucose level to normal values and did not cause any significant cytotoxicity compared to the control group (P=0.0698); there was no gain in weight between the MO treated and the control groups (P>0.8115). However, data showed that treatment with an ethanolic extract of MO caused a decrease in bicarbonate (P<0.0001), and more than twofold increase in anion gap (P<0.0001); metformin treatment also decreased bicarbonate (P<0.0001) and resulted in a threefold increase in anion gap (P<0.0001). Conclusively, these data show that while MO appears to have antidiabetic and noncytotoxic properties, it is associated with statistically significant anion gap acidosis in alloxan induced type 2 diabetic rats.
Chemokines in Cancer
Authors: Chow Melvyn T. , Luster Andrew D.
Published: December 2014

Chemokines are chemotactic cytokines that control the migration of cells between tissues and the positioning and interactions of cells within tissue. The chemokine superfamily consists of approximately 50 endogenous chemokine ligands and 20 G protein–coupled seven-transmembrane spanning signaling receptors. Chemokines mediate the host response to cancer by directing the trafficking of leukocytes into the tumor microenvironment. This migratory response is complex and consists of diverse leukocyte subsets with both antitumor and protumor activities. Although chemokines were initially appreciated as important mediators of immune cell migration, we now know that they also play important roles in the biology of nonimmune cells important for tumor growth and progression. Chemokines can directly modulate the growth of tumors by inducing the proliferation of cancer cells and preventing their apoptosis. They also direct tumor cell movement required for metastasis. Chemokines can also indirectly modulate tumor growth through their effects on tumor stromal cells and by inducing the release of growth and angiogenic factors from cells in the tumor microenvironment. In this Masters of Immunology primer, we focus on recent advances in understanding the complex nature of the chemokine system in tumor biology with a focus on how the chemokine system could be used to augment cancer immunotherapeutic strategies to elicit a more robust and long-lasting host antitumor immune response. Cancer Immunol Res; 2(12); 1125–31. ©2014 AACR.
Prenatal Diagnosis of Covered Cloacal Exstrophy
Authors: Mallmann Michael R. , Reutter Heiko , Müller Andreas , Boemers Thomas M. , Geipel Annegret , Berg Christoph , Gembruch Ulrich
Published: December 2014

The authors present the case of a prenatally diagnosed covered cloacal exstrophy in a female fetus and potential differential diagnoses within the exstrophy-epispadias complex. While on prenatal ultrasound, low-set umbilicus, omphalocele, diastasis of the pubic rami, split vulva and left-sided renal agenesis were suggestive of classic cloacal exstrophy, the presence of bladder filling and the missing characteristic elephant trunk appearance of the usually prolapsing terminal ileum suggested the diagnosis of covered cloacal exstrophy. Besides urogenital anomalies, the fetus presented with an additional small muscular ventricular septal defect. Postnatal presentation showed an omphalocele with a low-set umbilicus and a directly inferior positioned large everted (exstrophic) bladder plate with low positioned ureteric orifices. The external genitalia impressed with rudimentary vulvae and hemiclitorises. An imperforate anus was present, yet bowel movements were passed shortly after birth through a small vesicointestinal fistula positioned at the lower vesical trigone. We conclude that prenatal diagnosis of covered cloacal exstrophy can be made if bladder filling is present during prenatal ultrasound, although the bladder might become exstrophic during later gestation.
Stage-Related Outcome after Fetoscopic Laser Ablation in Twin-to-Twin Transfusion Syndrome
Authors: Has Recep , Kalelioglu Ibrahim , Corbacioglu Esmer Aytul , Ermis Hayri , Dural Ozlem , Dogan Yasemin , Yasa Cenk , Yumru Harika , Demir Omer , Yuksel Atil , Ibrahimoglu Lemi , Yildirim Alkan
Published: December 2014

Aim: To review the perinatal outcome of twin-to-twin transfusion syndrome (TTTS) treated with fetoscopic laser coagulation in a developing country with detailed analysis according to the stage of the syndrome. Methods: This was a retrospective study of 85 TTTS cases treated with fetoscopic laser coagulation at the Fetal Diagnosis and Treatment Unit of Istanbul Faculty of Medicine between January 2006 and March 2013. Results: The surgical failure rate was 5.8% (5/85). Among all the cases of the total cohort, only 1 fetus survived in 27 pregnancies (31.8%), and both fetuses survived in 22 pregnancies (25.9%). In 49 pregnancies (57.6%) at least one fetus survived at the end of the neonatal period. The overall survival and live birth rates were 41.8% (71/170) and 56.4% (96/170), respectively, and they significantly decreased as the stage of disease increased. Delivery occurred before 32 weeks of gestation in 54 (63.5%) pregnancies. Logistic regression analysis showed that gestational age at delivery was the only independent factor, and the risk of nonsurvival significantly decreased with increasing age. Conclusion: Based on our experience, the outcome of fetoscopic laser coagulation of the placental anastomoses for TTTS became worse as the Quintero stage of the disease advanced.
Gene Expression Profiling in Melasma in Korean Women
Authors: Chung Bo Young , Noh Tai Kyung , Yang Sang Hwa , Kim Il Hwan , Lee Mi Woo , Yoon Tae Jin , Chang Sung Eun
Published: December 2014

Background: There has been a paucity of data about the difference in gene expression between melasma lesional skin and normal adjacent one. Objective: Our aim was to identify novel genes involved in the pathogenesis of melasma. Methods: We performed a microarray analysis and confirmed the results on quantitative real-time polymerase chain reaction (qRT-PCR) in Korean women with melasma. Results: There were 334 genes whose degree of expression showed a significant difference between melasma lesional skin and normal adjacent one. Of these, five were confirmed on qRT-PCR. In melasma lesional skin, there were down-regulation of genes involved in the PPAR signaling pathway and up-regulation of genes involved in neuronal component and the functions of stratum corneum barrier. Conclusion: This result suggests that the pathogenesis of melasma might be associated with novel genes involved in the above signaling pathway in Korean women.
MicroRNAs in Atherosclerosis
Authors: Hosin Ali A. , Prasad Anoop , Viiri Leena E. , Davies Alun H. , Shalhoub Joseph
Published: December 2014

Micro-ribonucleic acids (miRNAs) are a class of endogenous non-coding ribonucleic acids that regulate gene expression. MiRNAs have been shown to act as key regulators in the vascular system, with wide-ranging physio-pathological effects. Atherosclerotic disease is a leading cause of morbidity and mortality worldwide. This review presents current knowledge on miRNAs implicated in atherosclerosis susceptibility, development and progression. They are involved in cell phenotype switching, response to shear stress, cell senescence, adhesion molecule expression, macrophage response to oxidised low-density lipoprotein, Toll-like receptor 4 expression, neointimal lesion formation, plaque angiogenesis and cellular cholesterol homeostasis. Clinically, early work has demonstrated the utility of miRNAs for differentiating patients with arterial disease from controls and predicting future cardiac events; this highlights potential diagnostic and prognostic roles. MiRNA involvement in the crucial stages of atherosclerosis promises new hope in treating arterial disease. However, issues regarding multiple miRNA targets, stability and delivery continue to present challenges. i 2014 S. Karger AG, Basel
Vascular Function of the Mesenteric Artery Isolated from Thyroid Hormone Receptor-E Knockout Mice
Authors: Liu Kiao Ling , Lo Ming , Canaple Laurence , Gauthier Karine , del Carmine Peggy , Beylot Michel
Published: December 2014

Objective: This study evaluated the consequences of thyroid hormone receptor-E (TRE) disruption on vascular reactivity. Methods: The activity of superior mesenteric arteries isolated from TRE knockout mice generated in the SV129 background (TRE0/0SV) or in a pure C57BL/6 background (TRE0/0C57) was compared to that of their corresponding wild-type strains (SV129 or C57BL/6 mice). Results: The wild-type SV129 mice exhibited an impaired acetylcholine (Ach)-induced mesenteric artery relaxation compared to C57BL/6 mice, associated with greater responses to angiotensin II (AII) and phenylephrine (PE). The disruption of TRE decreased the vascular response to sodium nitroprusside and PE in both the SV129 and C57BL/6 genetic backgrounds. Responses to Ach and AII were also blunted, but only in TRE0/0C57 mice. The administration of 3,3′5-triiodo-L-thyronine sodium salt (T3) elicited a vasodilatation in C57BL/6 mice even at the lowest concentration (10-9M); a maximal relaxation of more than 50% was observed with the concentrations between 10-9 and 10-8M. However, the response to T3 was nearly absent in TRE0/0C57 mice. Conclusion: TRE is essential for the control of vascular tone, particularly in thyroid hormone-mediated relaxation. The difference in response to Ach observed between the two wild-type mice should be taken into account for interpreting the vascular responses of genetically engineered mice. i 2014 S. Karger AG, Basel
Mineralocorticoid and SGK1-Sensitive Inflammation and Tissue Fibrosis
Authors: Artunc Ferruh , Lang Florian
Published: December 2014

Effects of mineralocorticoids are not restricted to regulation of epithelial salt transport, extracellular volume and blood pressure; mineralocorticoids also influence a wide variety of seemingly unrelated functions such as inflammation and fibrosis. The present brief review addresses the role of mineralocorticoids in the orchestration of these latter processes. Mineralocorticoids foster inflammation as well as vascular, cardiac, renal and peritoneal fibrosis. Mechanisms involved in mineralocorticoid-sensitive inflammation and fibrosis include the serum- and glucocorticoid-inducible kinase 1 (SGK1), which is genomically upregulated by mineralocorticoids and transforming growth factor β (TGF-β), and stimulated by mineralocorticoid-sensitive phosphatidylinositide 3-kinase. SGK1 upregulates the inflammatory transcription factor nuclear factor-κB, which in turn stimulates the expression of diverse inflammatory mediators including connective tissue growth factor. Moreover, SGK1 inhibits the degradation of the TGF-β-dependent transcription factors Smad2/3. Mineralocorticoids foster the development of TH17 cells, which is compromised following SGK1 deletion. Excessive SGK1 expression is observed in a wide variety of fibrosing diseases including lung fibrosis, diabetic nephropathy, glomerulonephritis, obstructive kidney disease, experimental nephrotic syndrome, obstructive nephropathy, liver cirrhosis, fibrosing pancreatitis, peritoneal fibrosis, Crohn's disease and celiac disease. The untoward inflammatory and fibrosing effects of mineralocorticoids could be blunted or even reversed by mineralocorticoid receptor blockers, which may thus be considered in the treatment of inflammatory and/or fibrosing disease.
Retrospective Analysis of a Combined Endoscopic and Transcutaneous Technique for the Management of Parotid Salivary Gland Stones
Authors: Numminen Jura , Sillanp(( Saara , Virtanen Jussi , Sipil( Markku , Rautiainen Markus
Published: December 2014

Sialendoscopy is used in the diagnosis and treatment of various symptoms relating to the salivary gland, e.g. chronic swelling or obstruction and inflammation of the salivary duct. Small intraductal stones can be removed with various instruments during sialendoscopy, whereas larger ones can be fragmented with extracorporeal shockwave lithotripsy or laser. However, 5-10% of the patients with parotid stones cannot be treated with these methods. In patients with large impacted stones or stones in a hilus area, a combined endoscopic and transcutaneous technique can be employed. The stone is approached endoscopically, a skin flap is raised over or a small incision is made through the illuminated area, and the stone is removed by an external route with minimal morbidity. This retrospective study analysed the cases of 8 patients treated using the combined technique, 6 of whom became symptom free. Superficial parotidectomy was performed in 1 patient. No complications were observed, and ductal stents were not used. The average diameter of the stones was 7.6 mm (range 7.0-10.2). The combined technique is recommended for the removal of large and impacted intraductal stones in the parotid gland. No major complications have been reported. i 2014 S. Karger AG, Basel
Gastrostomy Intraperitoneal Bumper Migration in a Three-Year-Old Child: A Rare Complication following Gastrostomy Tube Replacement
Authors: Guanà Riccardo , Lonati Luca , Barletti Claudio , Cisarò Fabio , Casorzo Ilaria , Carbonaro Giulia , Lezo Antonella , Delmonaco Angelo Giovanni , Mussa Alessandro , Capitanio Martina , Cussa Davide , Lemini Riccardo , Schleef Jürgen
Published: December 2014

Feeding gastrostomy is used worldwide for adults and children with feeding impairment to obtain long-term enteral nutrition. Percutaneous endoscopic gastrostomy insertion is considered the gold standard, but after the first months requires gastrostomy tube replacement with a low-profile button. The replacement is known as an easy procedure, but several minor and major complications may occur during and after the manoeuvre. We describe intraperitoneal bumper migration in a 3-year-old boy, a rare complication following gastrostomy tube replacement, and we discuss the recent literature regarding similar cases.