bluuebunny/crossref_metadata_2025 huggingface dataset:
Deviations in Geometry of Miniature Gears Fabricated by Wire Electrical Discharge Machining
Authors: Gupta Kapil , Jain N. K.
Published: April 2014

Functional performance of a gear during its service life depends on its manufacturing quality which is decided by the amount of deviations in the gear geometry. Most of the conventional miniature gear manufacturing processes (i.e. stamping, hobbing, powder-metallurgy, extrusion, die-casting) are unable to meet the very high quality requirements of miniature gears used in highly precise and sophisticated equipments such as devices used in MEMS, NEMS and timer mechanisms, robots, micro-motors, micro-pumps etc. Present work was undertaken to explore the use of wire electrical discharge machining (WEDM) as a superior alternative miniature gear manufacturing process. This paper reports on the deviations in macro-geometry (i.e. span, tooth thickness, dimensions over two-balls) and micro-geometry (single pitch deviation, runout, and surface finish) of WEDMed miniature external spur gears (having 9.8 mm outside diameter with 12 teeth) made of brass. The best quality WEDMed miniature gear had very less macro-geometry and micro-geometry deviations and belongs to American Gear Manufacturers Association (AGMA) quality range 8–11. The average surface roughness and maximum surface roughness were 1 μm and 6.4 μm respectively. The SEM images indicate tooth surfaces free from surface defects. Attempt was made to find the probable causes of deviations in geometry of WEDMed miniature gears. Comparative study of the WEDMed miniature gear with the hobbed gear was also done. The findings of the present work prove that using appropriate process parameters WEDM can manufacture superior quality miniature gears than by any conventional process.
Controlled Self-Assembly of Functionalized Carbon Nanotubes on Silicon Substrates
Authors: Mortuza S. M. , Banerjee Soumik
Published: April 2014

Self-assembly of carbon nanotubes (CNTs) on silicon substrates has myriad applications including nanotube based electrochemical energy conversion and storage devices, such as batteries and super-capacitors. Patterned assembly of CNTs is required in order to control the effective electrical conductivity and mechanical properties of these devices and achieve substantial improvement in their performance. Solution-based self-assembly of CNTs provides a cost-effective means to synthesize uniform vertically or horizontally aligned nanostructures on top of substrates. However, self-assembly of CNTs is a complex dynamical process that involves intermolecular interaction between the CNTs and that between the nanotubes and the substrate as well as solvent molecules. The transport properties of CNTs and solvents also play an important role. The scientific literature lacks detailed study of understanding the mechanism of self-assembly of CNTs on substrates during synthesis process. Often times, nanotubes are functionalized in an effort to make them more soluble and induce partial charges to control the self-assembly. Some of the key factors that govern the transportation and self-assembly of functionalized CNTs are surface charge density on substrate and electrostatic interaction of the functionalized CNTs with the substrate. In an effort to mimic the conditions during the synthesis of carbon nanomaterials on silicon substrate, we have employed molecular dynamics simulations to simulate both pure and functionalized CNTs sandwiched between silicon substrates in presence of commonly used solvent, water. Our simulations indicate that both pure and functionalized CNTs are not significantly soluble in water and form agglomerates. Our results also illustrate that neither pure nor functionalized CNTs tend to deposit on silicon substrates in water. Results presented in this study provide fundamental insight that can help to understand the agglomeration and orientation of CNTs in water.
Effects of Material Property and Geometry in Nanoindentation Simulation of Thin Film Mechanical Characterization
Authors: Ahsan Sanjida , Rahman Md Tahmidur , Tarefder Rafiqul A.
Published: April 2014

Nanoindentation of thin film-thick substrate system is a commonly employed tool to measure the mechanical properties of materials. Finite Element Method (FEM) simulation of nanoindentation experiment can overcome the expense and limitations of sophisticated test procedure. This study focused on the FEM simulation of nanoindentation test in ABAQUS environment to check the effects of film-substrate material properties and geometry. The indentation process in concern involves a two dimensional axisymmetric model where a thin film is placed above a substrate and indented by a rigid indenter for a specific friction condition. Modulus of elasticity and hardness of thin film has been calculated from analysis results using empirical relationship. For this study, two types of thin film properties i.e. elastic-perfectly plastic and elasto-plastic with specific strain hardening condition are taken for consideration. Firstly, different elastic substrate materials have been used under elastic-perfectly plastic thin film to observe the substrate strength effects. The analysis has been conducted for four different indentation depths to incorporate the influence of depth of penetration also. Secondly, similar analysis was performed for strain-hardening film material for all substrate strength to compare the behavior with perfectly plastic case. Finally, thickness of substrate layer has also been varied to observe the effect of substrate thickness under nanoindentation test. The simulation result shows that substrate strength effect is pronounced on film modulus determination whereas hardness is not significantly sensitive to this effect. Substrate modulus with magnitude smaller or near film modulus can predict reasonable value of film modulus whereas high strength substrate modulus i.e. rigid body as a substrate produces extremely high film modulus. Indentation derived film hardness affects significantly the elastic modulus due to incorporation of strain hardening in thin film properties. In addition, calculated film properties increase with the increment of indentation depth but show negligible change due to the variation of substrate thickness.
Feasibility Study of Heat Pump in Maine Using Attic Heat Source
Authors: Lin Lin , Knittweis Stephen , Doxsey Julie
Published: April 2014

Heat pumps have been widely studied and used as heating sources for decades in the southern part of the United States. In Maine, however, heat pumps are not popular because of a perception that they are of marginal utility in cold climates. Usage has generally been limited to ground-source units, which are expensive to install. Air-source devices require less up-front investment, and can be used as supplemental heat sources. This study focuses on the feasibility of heat pump usage in Maine by utilizing attic air as the heat source. To this end, a heat pump was installed to heat up a 150 liter water tank. Testing was conducted in fall and winter, and the results demonstrate the energy advantage of using a heat pump.
LabVIEW and Measure Foundry Based Data Acquisition System for Mechanical Engineering Technology Laboratories
Authors: Yilmaz Emin
Published: April 2014

Since the ASYST data acquisition and analysis software was discontinued and the old versions of ASYST do not support new computer operating systems and new data acquisition boards, old computer data acquisition (CDAQ) system is being replaced with a new data acquisition system. The new microcomputer based data acquisition system consists of an i-3 microcomputer with 3.0 GHz CPU and Windows-7 operating system, a Data Translation (DT) DT-304, 12-bit, 400 MHz data acquisition board with STP-300 screw terminal, Data Translation Measure Foundry (DT-MF) software and DT-LV link software [2], a National Instruments (NI) PCI-6250, M-series, low level, 16-bit, 1.25 MS/s board with 4-module SCC-68 I/O Connector Block, four thermocouple-input plug-in modules and NI LabVIEW (NI-LV) software [4]. Data Translation’s DT-LV software links DT boards with NI-LV software. Most ASYST-based data acquisition and analysis application programs used in Mechanical Engineering Technology (MET) courses have been converted to NI-LV and DT-MF application programs.

Purpose of this paper is to describe how our old data acquisition application programs were converted to new data acquisition application programs so that they may be used with our new data acquisition system. Descriptions of the experiments, equipment used, and experiences gained with laboratory experiments are given elsewhere [8–13]. Specifically: Reference [8] covers upgrades made to the Materials Testing Laboratory, including Tinius-Olsen [14] tensile testing machine; reference [9] covers design and development of data acquisition programs for the materials testing, including Tensile Testing of Materials experiment; references [11] and [12] cover Heating Ventilating and Air Conditioning (HVAC) experiments and use of DAQ system in these experiments; reference [13] cover all uses of DAQ system in MET at University of Maryland Eastern Shore (UMES).
Multi-Dimensional Modeling of Lithium-Air Batteries
Authors: Wang Yun , Cho Sung Chan
Published: April 2014

In this study, we develop a multi-dimensional model of lithium-air (Li-air) batteries to evaluate their performance. The model consists of a set of partial differential equations of species and charges conservation, in conjunction of the electrochemical reaction kinetics at the reaction interface, and takes into account two major mechanisms of voltage loss due to insoluble discharge products formation: namely, electrode passivation and increased oxygen transport resistance. The model is successfully implemented to numerical simulation of discharging operation of a two-dimensional Li-air battery. Highly non-uniform distributions of oxygen and insoluble products are revealed under high current density. The pore space in the electrode is not fully utilized, particularly under high discharging current operation. The fundamental model and numerical tool are important for developing high-performance Li-air batteries.
Interfacial Debonding of Glass Single Fiber Composites Using the Johnson-Cook Failure Model
Authors: Tenorio Max , Pelegri Assimina A.
Published: April 2014

The interfacial relationship between a glass fiber bundle and epoxy resin is investigated both experimentally and computationally. A cylindrical notched specimen with a single bundle of fibers along the axis is created to observe debonding behavior. All specimens reached a critical stress value and exhibited debonding to some degree. All material properties are obtained experimentally. The Johnson-Cook failure model is used to simulate the experimental results. The computational model exhibits realistic stress distribution as well as calculates element deletion to simulate interfacial debonding. Simulation refinement will be necessary, especially at the interface, to produce more explicit results.
A Numerical Study for Biomimetic Structures to Control Wall Shear Stress in Water
Authors: Gerber Matthew J.
Published: April 2014

There are numerous practical applications whose operational efficiency depends on the shear stress (skin friction drag) on their functional surfaces, including artificial reefs, artificial hearts, and continuous flow microbial fuel cells. For the most part, the fundamental physics that govern surface shear stress are well understood and established, especially for relatively simple shapes such as a sphere or cylinder. However, the use of passive, bio-inspired, additive structures to control surface shear stress has thus far seen limited investigation. To evaluate the effect of geometrical forms on surface shear stress, 29 biomimetic structures based on sharkskin, cacti, and ocean-dwelling suspension feeders were studied. The structures were modeled in COMSOL Multiphysics, and the shear stresses on their surfaces were studied. The results show that shear stress on the surface of a structure depends not only on surface area, but also on the general form of the structure. In addition, the surface shear stress of some structures display a strong dependence on fluid-flow orientation, while others do not.
Pressure Drop Analysis of a Pressure-Channel Type SuperCritical Water-Cooled Reactor
Authors: Dragunov A. , Peiman W.
Published: April 2014

Pressure drop calculation and temperature profiles associated with fuel and sheath are important aspects of a nuclear reactor design. The main objective of this paper is to determine the pressure drop in a fuel channel of a SuperCritical Water-cooled Reactor (SCWR) and to calculate the temperature profile of the sheath and the fuel bundles. One-dimensional steady-state thermal-hydraulic analysis was conducted. In this study, the pressure drops due to friction, acceleration, local losses, and gravity were calculated at supercritical conditions.
Te Kapa o Taika: A Commentary on Boy
Authors: Hokowhitu Brendan
Published: April 2014

Te Kapa o Taika: A Commentary on Boy
Micro(RNA)managing Endothelial Regeneration
Authors: Erbay Ebru
Published: April 2014

Systemic targeting of miR-126 production might be useful in treating atherosclerosis.
Classification, Identification, and Clinical Significance of Haemophilus and Aggregatibacter Species with Host Specificity for Humans
Authors: Nørskov-Lauritsen Niels
Published: April 2014

The aim of this review is to provide a comprehensive update on the current classification and identification ofHaemophilusandAggregatibacterspecies with exclusive or predominant host specificity for humans.Haemophilus influenzaeand some of the otherHaemophilusspecies are commonly encountered in the clinical microbiology laboratory and demonstrate a wide range of pathogenicity, from life-threatening invasive disease to respiratory infections to a nonpathogenic, commensal lifestyle. New species ofHaemophilushave been described (Haemophilus pittmaniaeandHaemophilus sputorum), and the new genusAggregatibacterwas created to accommodate some formerHaemophilusandActinobacillusspecies (Aggregatibacter aphrophilus,Aggregatibacter segnis, andAggregatibacter actinomycetemcomitans).Aggregatibacterspecies are now a dominant etiology of infective endocarditis caused by fastidious organisms (HACEK endocarditis), andA. aphrophilushas emerged as an important cause of brain abscesses. Correct identification ofHaemophilusandAggregatibacterspecies based on phenotypic characterization can be challenging. It has become clear that 15 to 20% of presumptiveH. influenzaeisolates from the respiratory tracts of healthy individuals do not belong to this species but represent nonhemolytic variants ofHaemophilus haemolyticus. Due to the limited pathogenicity ofH. haemolyticus, the proportion of misidentified strains may be lower in clinical samples, but even among invasive strains, a misidentification rate of 0.5 to 2% can be found. Several methods have been investigated for differentiation ofH. influenzaefrom its less pathogenic relatives, but a simple method for reliable discrimination is not available. With the implementation of identification by matrix-assisted laser desorption ionization–time of flight mass spectrometry, the more rarely encountered species ofHaemophilusandAggregatibacterwill increasingly be identified in clinical microbiology practice. However, identification of some strains will still be problematic, necessitating DNA sequencing of multiple housekeeping gene fragments or full-length 16S rRNA genes.
Prosthetic Joint Infection
Authors: Tande Aaron J. , Patel Robin
Published: April 2014

Prosthetic joint infection (PJI) is a tremendous burden for individual patients as well as the global health care industry. While a small minority of joint arthroplasties will become infected, appropriate recognition and management are critical to preserve or restore adequate function and prevent excess morbidity. In this review, we describe the reported risk factors for and clinical manifestations of PJI. We discuss the pathogenesis of PJI and the numerous microorganisms that can cause this devastating infection. The recently proposed consensus definitions of PJI and approaches to accurate diagnosis are reviewed in detail. An overview of the treatment and prevention of this challenging condition is provided.
OXA β-Lactamases
Authors: Evans Benjamin A. , Amyes Sebastian G. B.
Published: April 2014

The OXA β-lactamases were among the earliest β-lactamases detected; however, these molecular class D β-lactamases were originally relatively rare and always plasmid mediated. They had a substrate profile limited to the penicillins, but some became able to confer resistance to cephalosporins. From the 1980s onwards, isolates of
Acinetobacter baumannii
that were resistant to the carbapenems emerged, manifested by plasmid-encoded β-lactamases (OXA-23, OXA-40, and OXA-58) categorized as OXA enzymes because of their sequence similarity to earlier OXA β-lactamases. It was soon found that every
A. baumannii
strain possessed a chromosomally encoded OXA β-lactamase (OXA-51-like), some of which could confer resistance to carbapenems when the genetic environment around the gene promoted its expression. Similarly,
Acinetobacter
species closely related to
A. baumannii
also possessed their own chromosomally encoded OXA β-lactamases; some could be transferred to
A. baumannii
, and they formed the basis of transferable carbapenem resistance in this species. In some cases, the carbapenem-resistant OXA β-lactamases (OXA-48) have migrated into the
Enterobacteriaceae
and are becoming a significant cause of carbapenem resistance. The emergence of OXA enzymes that can confer resistance to carbapenems, particularly in
A. baumannii
, has transformed these β-lactamases from a minor hindrance into a major problem set to demote the clinical efficacy of the carbapenems.
Keeping NAION visual loss: discriminating urgent versus emergent visual loss in an elderly female
Authors: Luber Sarah , Alweis Richard
Published: April 2014

A 72-year-old woman presented with sudden, monocular vision loss and a temporal headache without eye pain. Examination revealed complete loss of vision in the right eye in bilateral superior visual fields and hyperaemic oedema with haemorrhages of the optic disc. She had significant vasculopathic risk factors, including age greater than 50 years, hypertension, recent coronary artery bypass graft and hyperlipidaemia. Atypical features were investigated, including simultaneous vision changes in contralateral eye, prodrome, jaw claudication, scalp tenderness and headache. The patient indicated persistent temporal headaches since the onset of the visual changes, prompting investigation with temporal biopsy and inflammatory markers with initiation of steroids. Diagnostic studies excluded inflammatory disease and retinal vascular thrombosis. The patient was diagnosed with non-arteritic anterior ischaemic optic neuropathy (NAION) and the steroids were tapered off. At 6 months, the patient has maintained altitudinal visual loss, but her central vision in the affected eye has remained 20/25.
Tadalafil enhances the neuroprotective effects of ischemic postconditioning in mice, probably in a nitric oxide associated manner
Authors: Gulati Puja , Singh Nirmal
Published: April 2014

This study investigates the modulatory effect of tadalafil, a selective phosphodiesterase (PDE-5) inhibitor, on the neuroprotective effects of ischemic postconditioning (iPoCo) in mice. Bilateral carotid artery occlusion (BCAO) for 12 min followed by reperfusion for 24 h was employed to produce ischemia and reperfusion induced cerebral injury. Cerebral infarct size was measured using TTC staining. Memory was assessed using the Morris water maze test. Degree of motor incoordination was evaluated using inclined beam-walking, rota-rod, and lateral push tests. Brain nitrite/nitrate, acetylcholinesterase activity, TBARS, and glutathione levels were also estimated. BCAO followed by reperfusion produced a significant increase in cerebral infarct size, brain nitrite/nitrate and TBARS levels, and acetylcholinesterase activity along with a reduction in glutathione. Marked impairment of memory and motor coordination was also noted. iPoCo consisting of 3 episodes of 10 s carotid artery occlusion and reperfusion instituted immediately after BCAO significantly decreased infarct size, memory impairment, motor incoordination, and altered biochemistry. Pretreatment with tadalafil mimicked the neuroprotective effects of iPoCo. The tadalafil-induced neuroprotective effects were significantly attenuated by l-NAME, a nonselective NOS inhibitor. We concluded that tadalafil mimics the neuroprotective effects of iPoCo, probably through a nitric oxide dependent pathway, and PDE-5 could be a target of interest with respect to the neuroprotective mechanism of iPoCo.
SOME RESULTS FOR THE RUPTURE DEGREE
Authors: AYTAÇ AYSUN , AKSU HANIFE
Published: April 2014

The rupture degree of an incomplete connected graph G is defined by[Formula: see text] where w(G − S) denotes the number of components in the graph G − S and m(G − S) is the order of the largest component of G − S. This parameter can be used to measure the vulnerability of a graph. In this paper, some bounds consisted of the relationships between the rupture degree and some vulnerability parameters on the rupture degree of a graph are given.
Phase transition, quasinormal modes and Hawking radiation of Schwarzschild black hole in quintessence field
Authors: Tharanath R. , Varghese Nijo , Kuriakose V. C.
Published: April 2014

Black hole thermodynamic stability can be determined by studying the nature of heat capacity of the system. For Schwarzschild black hole the heat capacity is negative, but in the quintessence field, this system shows a second-order phase transition, implying the existence of a stable phase. We further discuss the equation of state of the present system. While analyzing the quasinormal modes (QNM), we find that the massive scalar QNM frequencies in the complex ω plane shows a dramatic change when we plot it as a progressive function of quintessence state parameter. We also find the Hawking temperature of the system via the method of tunneling.
Stochastic integration with respect to cylindrical Lévy processes in Hilbert spaces: An L2 approach
Authors: Riedle Markus
Published: March 2014

In this work stochastic integration with respect to cylindrical Lévy processes with weak second moments is introduced. It is well known that a deterministic Hilbert–Schmidt operator radonifies a cylindrical random variable, i.e. it maps a cylindrical random variable to a classical Hilbert space valued random variable. Our approach is based on a generalisation of this result to the radonification of the cylindrical increments of a cylindrical Lévy process by random Hilbert–Schmidt operators. This generalisation enables us to introduce a Hilbert space valued random variable as the stochastic integral of a predictable stochastic process with respect to a cylindrical Lévy process. We finish this work by deriving an Itô isometry and by considering shortly stochastic partial differential equations driven by cylindrical Lévy processes.
A new characterization of Cohen–Macaulay rings
Authors: Bahmanpour Kamal , Naghipour Reza
Published: April 2014

The purpose of this paper is to provide a new characterization of Cohen–Macaulay local rings. As a consequence we deduce that a local (Noetherian) ring R is Gorenstein if and only if every parameter ideal of R is irreducible.
FINITE ELEMENT ANALYSIS OF THE DYNAMIC BEHAVIOR OF ALUMINUM HONEYCOMBS
Authors: XU SHANQING , RUAN DONG , BEYNON JOHN H.
Published: April 2014

In this paper, a finite element model was built using ANSYS/LS-DYNA to study the effect of strain rate on the dynamic out-of-plane plateau stress of aluminum honeycombs under constant velocity impact. The strain rates vary from 102 to 104 s-1. It has been found that the t/l ratio (wall thickness to edge length ratio) and strain rate have great influence on deformation pattern and plateau stress. The effect of strain rate on the plateau stress under high velocity impact was found to be different from that under low strain rate compression. The threshold impact velocity is approximately 100 m/s for the aluminum honeycomb studied.
South Korea in 2013
Authors: CHOO Jaewoo
Published: April 2014

In 2013 South Korea elected Asia's first female president. President Park Geunhye enjoyed high approval rating of 60% on average, possibly due to her diplomatic success with the United States and China and her firm North Korean policy. Unemployment trended downwards and South Korea's Kaesong Industrial Complex in North Korea reopened amid controversies. Relations with the North are however likely to worsen with mounting speculation of Pyongyang's possible fourth nuclear test.
EXPERIMENTAL INVESTIGATION OF A REFRIGERATION SYSTEM WORKING UNDER TRANSIENT CONDITIONS
Authors: DABAS J. K. , KUMAR SUDHIR , DODEJA A. K. , KASANA K. S.
Published: April 2014

The impact of transient conditions along with varied capillary tube length and charge quantity over the performance of a simple refrigeration system under all time transient operations has been investigated in a specially designed experimental setup. A maximum drop of 75% in the coefficient of performance (COP) of the system was recorded by the end of the transient cooling period. The continuous deterioration in performance from start to end of the transient cooling job can be well minimized by the optimum selection of capillary tube length and charge quantity. This paper refers some of the existing methods to determine the appropriate length of the coiled capillary tube and charge quantity for a newly designed refrigeration machine working under steady state conditions and compares the experimental results of transient operation with these. Optimum charge quantity for transient operation in the present study is 3.5% to 5% less than that calculated by the existing analytical and numerical methods. The optimum length of coiled capillary tube for transient operation as found in this experimental study matches approximately with the length predicted by the existing dimensionless correlation on the basis of design parameters as estimated towards the end of the transient cooling period.
The growth status of relaxor-based ferroelectric crystals and their development trends
Authors: Xu Guisheng , Yang Danfeng , Liu Jinfeng , Liu Ying , Chen Xiaxia
Published: March 2014

Our progress in the growth of ternary system Pb ( In 1/2 Nb 1/2) O 3– Pb ( Mg 1/3 Nb 2/3) O 3– PbTiO 3 (PIMNT) crystals and reviews on the possible developing trends in the piezoelectric crystals are presented. Large PIMNT crystals with 3 inches in diameter have been grown by using a modified Bridgman method. Meanwhile, Mn -doped PIMNT crystals have also been obtained. PIMNT crystals exhibit Curie temperature Tc ~ 190° C , rhombohedral–tetragonal phase transition temperature T rt > 100° C and coercive field Ec ~ 5.0–7.0 kV/cm on (001) cuts. Meanwhile, higher piezoelectric constant d32 ~ -1500–2200 pC/N , d15 ~ 4000–6000 pC/N and coercive field Ec ~ 7.0–9.0 kV/cm have been achieved on (110) cuts. The development trends of relaxor-based ferroelectric crystals are suggested to grow novel crystals with high rhombohedral–tetragonal phase transition temperature T rt > 150 ~ 160° C and/or high coercive field Ec and mechanical quality factor Qm, to promote growth efficiency of PIMNT crystals and to create new growth methods fitting for the growth of metastable or instable crystals.
Dynamical Outcomes of Quenching: Reflections on a Conical Intersection
Authors: Lehman Julia H. , Lester Marsha I.
Published: April 2014

This review focuses on experimental studies of the dynamical outcomes following collisional quenching of electronically excited OH A2Σ+radicals by molecular partners. The experimental observables include the branching between reactive and nonreactive decay channels, kinetic energy release, and quantum state distributions of the products. Complementary theoretical investigations reveal regions of strong nonadiabatic coupling, known as conical intersections, which facilitate the quenching process. The dynamical outcomes observed experimentally are connected to the local forces and geometric properties of the nuclei in the conical intersection region. Dynamical calculations for the benchmark OH-H2system are in good accord with experimental observations, demonstrating that the outcomes reflect the strong coupling in the conical intersection region as the system evolves from the excited electronic state to quenched products.
Estrogen signaling prevents diet-induced hepatic insulin resistance in male mice with obesity
Authors: Zhu Lin , Martinez Melissa N. , Emfinger Christopher H. , Palmisano Brian T. , Stafford John M.
Published: April 2014

The development of insulin resistance in the liver is a key event that drives dyslipidemia and predicts diabetes and cardiovascular risk with obesity. Clinical data show that estrogen signaling in males helps prevent adiposity and insulin resistance, which may be mediated through estrogen receptor-α (ERα). The tissues and pathways that mediate the benefits of estrogen signaling in males with obesity are not well defined. In female mice, ERα signaling in the liver helps to correct pathway-selective insulin resistance with estrogen treatment after ovariectomy. We assessed the importance of liver estrogen signaling in males using liver ERα-knockout (LKO) mice fed a high-fat diet (HFD). We found that the LKO male mice had decreased insulin sensitivity compared with their wild-type floxed (fl/fl) littermates during hyperinsulinemic euglycemic clamps. Insulin failed to suppress endogenous glucose production in LKO mice, indicating liver insulin resistance. Insulin promoted glucose disappearance in LKO and fl/fl mice similarly. In the liver, insulin failed to induce phosphorylation of Akt-Ser473and exclude FOXO1 from the nucleus in LKO mice, a pathway important for liver glucose and lipid metabolism. Liver triglycerides and diacylglycerides were also increased in LKO mice, which corresponded with dysregulation of insulin-stimulated ACC phosphorylation and DGAT1/2 protein levels. Our studies demonstrate that estrogen signaling through ERα in the liver helps prevent whole body and hepatic insulin resistance associated with HFD feeding in males. Augmenting hepatic estrogen signaling through ERα may lessen the impact of obesity on diabetes and cardiovascular risk in males.
Activation of mTORC1 signaling and protein synthesis in human muscle following blood flow restriction exercise is inhibited by rapamycin
Authors: Gundermann David M. , Walker Dillon K. , Reidy Paul T. , Borack Michael S. , Dickinson Jared M. , Volpi Elena , Rasmussen Blake B.
Published: April 2014

Restriction of blood flow to a contracting muscle during low-intensity resistance exercise (BFR exercise) stimulates mTORC1 signaling and protein synthesis in human muscle within 3 h postexercise. However, there is a lack of mechanistic data to provide a direct link between mTORC1 activation and protein synthesis in human skeletal muscle following BFR exercise. Therefore, the primary purpose of this study was to determine whether mTORC1 signaling is necessary for stimulating muscle protein synthesis after BFR exercise. A secondary aim was to describe the 24-h time course response in muscle protein synthesis and breakdown following BFR exercise. Sixteen healthy young men were randomized to one of two groups. Both the control (CON) and rapamycin (RAP) groups completed BFR exercise; however, RAP was administered 16 mg of the mTOR inhibitor rapamycin 1 h prior to BFR exercise. BFR exercise consisted of four sets of leg extension exercise at 20% of 1 RM. Muscle biopsies were collected from the vastus lateralis before exercise and at 3, 6, and 24 h after BFR exercise. Mixed-muscle protein fractional synthetic rate increased by 42% at 3 h postexercise and 69% at 24 h postexercise in CON, whereas this increase was inhibited in the RAP group. Phosphorylation of mTOR (Ser2448) and S6K1 (Thr389) was also increased in CON but inhibited in RAP. Mixed-muscle protein breakdown was not significantly different across time or groups. We conclude that activation of mTORC1 signaling and protein synthesis in human muscle following BFR exercise is inhibited in the presence of rapamycin.
Insulin sensitivity index in type 1 diabetes and following human islet transplantation: comparison of the minimal model to euglycemic clamp measures
Authors: Rickels Michael R. , Kong Stephanie M. , Fuller Carissa , Dalton-Bakes Cornelia , Ferguson Jane F. , Reilly Muredach P. , Teff Karen L. , Naji Ali
Published: April 2014

Insulin sensitivity is impaired in type 1 diabetes (T1D) and may be enhanced by islet transplantation, an effect best explained by improved metabolic control. While the minimal model index of insulin sensitivity, SI, has been used in studies of T1D, it has not before been evaluated against gold-standard measures derived from the euglycemic clamp. We sought to determine how well minimal model SI derived from an insulin-modified frequently sampled intravenous glucose tolerance (FSIGT) test compared with total body and peripheral insulin sensitivity estimates derived from the hyperinsulinemic-euglycemic clamp in subjects with T1D and following islet transplantation. Twenty-one T1D subjects were evaluated, including a subgroup ( n = 12) studied again after intrahepatic islet transplantation, with results compared with normal controls ( n = 11 for the FSIGT). The transplant recipients received 9,648 ± 666 islet equivalents/kg with reduction in HbA1c from 7.1 ± 0.2 to 5.5 ± 0.1% ( P < 0.01) and 10/12 were insulin independent. FSIGT-derived SI was reduced in T1D pre- compared with posttransplant and with normal [1.76 ± 0.45 vs. 4.21 ± 0.34 vs. 4.45 ± 0.81 × 10−4(μU/ml)−1·min−1; P < 0.01 for both]. Similarly, clamp-derived total body, and by the isotopic dilution method with [6,6-2H2]glucose, peripheral insulin sensitivity increased in T1D from pre- to posttransplant ( P < 0.05 for both). The predictive power ( r2) between volume-corrected SIC and measures of total and peripheral insulin sensitivity was 0.66 and 0.70, respectively ( P < 0.00001 for both). That the minimal model SIC is highly correlated to the clamp-derived measures indicates that the FSIGT is an appropriate methodology for the determination of insulin sensitivity in T1D and following islet transplantation.
Identification of genetic loci associated with different responses to high-fat diet-induced obesity in C57BL/6N and C57BL/6J substrains
Authors: Heiker John T. , Kunath Anne , Kosacka Joanna , Flehmig Gesine , Knigge Anja , Kern Matthias , Stumvoll Michael , Kovacs Peter , Blüher Matthias , Klöting Nora
Published: April 2014

We have recently demonstrated that C57BL/6NTac and C57BL/6JRj substrains are significantly different in their response to high-fat diet-induced obesity (DIO). The C57BL/6JRj substrain seems to be protected from DIO and genetic differences between C57BL/6J and C57BL/6N substrains at 11 single nucleotide polymorphism (SNP) loci have been identified. To define genetic variants as well as differences in parameters of glucose homeostasis and insulin sensitivity between C57BL/6NTac and C57BL/6JRj substrains that may explain the different response to DIO, we analyzed 208 first backcross (BC1) hybrids of C57BL/6NTac and C57BL/6JRj [(C57BL/6NTac × C57BL/6JRj)F1 × C57BL/6NTac] mice. Body weight, epigonadal and subcutaneous fat mass, circulating leptin, as well as parameters of glucose metabolism were measured after 10 wk of high-fat diet (HFD). Genetic profiling of BC1 hybrids were performed using TaqMan SNP genotyping assays. Furthermore, to assess whether SNP polymorphisms could affect mRNA level, we carried out gene expression analysis in murine liver samples. Human subcutaneous adipose tissue was used to verify murine data of SNAP29. We identified four sex-specific variants that are associated with the extent of HFD-induced weight gain and fat depot mass. BC1 hybrids carrying the combination of risk or beneficial alleles exhibit the phenotypical extremes of the parental strains. Murine and human SC expression analysis revealed Snap29 as strongest candidate. Our data indicate an important role of these loci in responsiveness to HFD-induced obesity and suggest genes of the synaptic vesicle release system such as Snap29 being involved in the regulation of high-fat DIO.
Can Vascular Endothelial Growth Factor and Microvessel Density Be Used as Prognostic Biomarkers for Colorectal Cancer? A Systematic Review and Meta-Analysis
Authors: Wang Yibaina , Yao Xiaoping , Ge Jie , Hu Fulan , Zhao Yashuang
Published: March 2014

Background.Vascular endothelial growth factor (VEGF) and microvessel density (MVD) are associated with greater incidence of metastases and decreased survival. Whether they can be used as prognostic indicators of colorectal cancer (CRC) is still controversial.Methods.The authors performed a meta-analysis using the results of a literature search of databases of PubMed and EMBASE, and the references of articles included in the analysis. Meta-analysis was performed using random effects model and hazard ratios (HRs) and 95% confidence intervals (CIs) as effect measures.Results. Twenty studies contributed to the analysis of VEGF, of which 16 were used for overall survival (OS) and 9 for disease-free survival (DFS). High VEGF levels has a relationship with unfavorable survival (OS: HR = 1.98, 95% CI: 1.30–3.02; DFS: HR = 2.10, 95% CI: 1.26–3.49) and a 4.22-fold increase in the rate of distant metastases. Analysis was performed on 18 studies for MVD; the results showed that patients with high MVD expression in tumors appeared to have poorer overall survival (HR = 1.39, 95% CI: 1.22–1.58) and were at a greater risk of having unfavorable clinical characteristics related to prognosis. Corresponding results were obtained from quantitative and/or qualitative analysis of clinicopathological.Conclusions. The meta-analysis demonstrates that VEGF and MVD can be used as prognostic biomarkers for CRC patients.
Self‐Excited Single‐Stage Power Factor Correction Driving Circuit for LED Lighting
Authors: Chang Yong-Nong
Published: March 2014

This pa per proposes a self‐excited single‐stage high power factor LED lighting driving circuit. Being featured with power factor correction capability without needing any control devices, the proposed circuit structure is with low cost and suitable for commercial production. The power factor correction function is accomplished by using inductor in combination with a half‐bridge quasi resonant converter to achieve active switching and yield out voltage regulation according to load requirement. Furthermore, the zero‐voltage switching in the half‐bridge converter can be attained to promote the overall performance efficiency of the proposed circuit. Finally, the validity and production availability of the proposed circuit will be verified as well.
Calculation of the Instream Ecological Flow of the Wei River Based on Hydrological Variation
Authors: Huang Shengzhi , Chang Jianxia , Huang Qiang , Wang Yimin , Chen Yutong
Published: April 2014

It is of great significance for the watershed management department to reasonably allocate water resources and ensure the sustainable development of river ecosystems. The greatly important issue is to accurately calculate instream ecological flow. In order to precisely compute instream ecological flow, flow variation is taken into account in this study. Moreover, the heuristic segmentation algorithm that is suitable to detect the mutation points of flow series is employed to identify the change points. Besides, based on the law of tolerance and ecological adaptation theory, the maximum instream ecological flow is calculated, which is the highest frequency of the monthly flow based on the GEV distribution and very suitable for healthy development of the river ecosystems. Furthermore, in order to guarantee the sustainable development of river ecosystems under some bad circumstances, minimum instream ecological flow is calculated by a modified Tennant method which is improved by replacing the average flow with the highest frequency of flow. Since the modified Tennant method is more suitable to reflect the law of flow, it has physical significance, and the calculation results are more reasonable.
Adaptive Backstepping Control Based on Floating Offshore High Temperature Superconductor Generator for Wind Turbines
Authors: Yang Feng , Li Sheng-shan , Wang Lei , Zuo Shan , Song Qing-wang
Published: March 2014

With the rapid development of offshore wind power, the doubly fed induction generator and permanent magnet synchronous generator cannot meet the increasing request of power capacity. Therefore, superconducting generator should be used instead of the traditional motor, which can improve generator efficiency, reduce the weight of wind turbines, and increase system reliability. This paper mainly focuses on nonlinear control in the offshore wind power system which is consisted of a wind turbine and a high temperature superconductor generator. The proposed control approach is based on the adaptive backstepping method. Its main purpose is to regulate the rotor speed and generator voltage, therefore, achieving the maximum power point tracking (MPPT), improving the efficiency of a wind turbine, and then enhancing the system’s stability and robustness under large disturbances. The control approach can ensure high precision of generator speed tracking, which is confirmed in both the theoretical analysis and numerical simulation.
The Construction of the Dupin Cyclides in a Smectic A Polygonal Texture
Authors: Meyer Claire , Jonckheere Brice , Penaud Coline
Published: March 2014

We report experimental observations with optical microscopy of the usual so-called polygonal texture. We have made simulations of the Dupin cyclides in one small region of the sample.
Poly(Butylene Terephthalate) Based Composites Containing Alumina Whiskers: Influence of Filler Functionalization on Dielectric Properties
Authors: Russo Pietro , Cimino Francesca , Acierno Domenico , Lupò Giovanni , Petrarca Carlo
Published: April 2014

Poly(butylene terephthalate) (PBT) is one of the most widely used semicrystalline thermoplastics polyester because of its superior thermal and mechanical properties, high dimensional stability and excellent processability. In this research PBT-based nanocomposites, including various amounts (up to 10 wt%) of commercial alumina whiskers, have been prepared by using a Brabender internal chamber mixer and analysed in terms of morphological features and dielectric properties. Specific attention has been focused on the effect of the filler functionalization considering 3-glycidoxy propylmethoxysilane (GPS) or 3-methacryloxypropyltrimethoxysilane (MPS) as coupling agents. Tests, performed on compounds filled with neat and functionalized alumina whiskers, show a clear dependence of relative dielectric permittivityεr, invariance of dissipation factor (tgδ), and a sensible increase of volume electrical resistivity(ρv)with the filler’s content and are encouraging for a future introduction of such composites in many electrical applications.
A Global Optimization Algorithm for Signomial Geometric Programming Problem
Authors: Hou Xue-Ping , Shen Pei-Ping , Chen Yong-Qiang
Published: March 2014

This paper presents a global optimization algorithm for solving the signomial geometric programming (SGP) problem. In the algorithm, by the straight forward algebraic manipulation of terms and by utilizing a transformation of variables, the initial nonconvex programming problem (SGP) is first converted into an equivalent monotonic optimization problem and then is reduced to a sequence of linear programming problems, based on the linearizing technique. To improve the computational efficiency of the algorithm, two range reduction operations are combined in the branch and bound procedure. The proposed algorithm is convergent to the global minimum of the (SGP) by means of the subsequent solutions of a series of relaxation linear programming problems. And finally, the numerical results are reported to vindicate the feasibility and effectiveness of the proposed method.
Pointwise Multipliers on Spaces of Homogeneous Type in the Sense of Coifman and Weiss
Authors: Han Yanchang , Liao Fanghui , Liu Zongguang
Published: March 2014

By applying the remarkable orthonormal basis constructed recently by Ausher and Hytönen on spaces of homogeneous type in the sense of Coifman and Weiss, pointwise multipliers of inhomogeneous Besov and Triebel-Lizorkin spaces are obtained. We make no additional assumptions on the quasi-metric or the doubling measure. Hence, the results of this paper extend earlier related results to a more general setting.
On the Nature of Electronic Wave Functions in One-Dimensional Self-Similar and Quasiperiodic Systems
Authors: Maciá Enrique
Published: March 2014

The interest in the precise nature of critical states and their role in the physics of aperiodic systems has witnessed a renewed interest in the last few years. In this work we present a review on the notion of critical wave functions and, in the light of the obtained results, we suggest the convenience of some conceptual revisions in order to properly describe the relationship between the transport properties and the wave functions distribution amplitudes for eigen functions belonging to singular continuous spectra related to both fractal and quasiperiodic distribution of atoms through the space.
Clustering and Genetic Algorithm Based Hybrid Flowshop Scheduling with Multiple Operations
Authors: Zhang Yingfeng , Liu Sichao , Sun Shudong
Published: March 2014

This research is motivated by a flowshop scheduling problem of our collaborative manufacturing company for aeronautic products. The heat‐treatment stage (HTS) and precision forging stage (PFS) of the case are selected as a two‐stage hybrid flowshop system. In HTS, there are four parallel machines and each machine can process a batch of jobs simultaneously. In PFS, there are two machines. Each machine can install any module of the four modules for processing the workpeices with different sizes. The problem is characterized by many constraints, such as batching operation, blocking environment, and setup time and working time limitations of modules, and so forth. In order to deal with the above special characteristics, the clustering and genetic algorithm is used to calculate the good solution for the two‐stage hybrid flowshop problem. The clustering is used to group the jobs according to the processing ranges of the different modules of PFS. The genetic algorithm is used to schedule the optimal sequence of the grouped jobs for the HTS and PFS. Finally, a case study is used to demonstrate the efficiency and effectiveness of the designed genetic algorithm.