bluuebunny/crossref_metadata_2025 huggingface dataset:
Asymptotic Approach to Oblique Cross-Sectional Analysis of Beams
Authors: Rajagopal Anurag , Hodges Dewey H.
Published: September 2013

Structural and aeroelastic analyses using beam theories by default choose a cross section that is perpendicular to the reference line. In several cases, such as swept wings with high AR, a beam theory that allows for the choice of a cross section that is oblique to the reference line may be more convenient. This work uses the variational asymptotic method (VAM) to develop such a beam theory. The problems addressed are the planar deformation of a strip and the full 3D deformation of a solid, prismatic, right-circular cylinder, both made of homogeneous, isotropic material. The motivation for choosing these problems is primarily the existence of 3D elasticity solutions, which comprise a complete validation set for all possible deformations and which are shown to be accurately captured by the current analysis. A secondary motivation was that the development and final results of the beam theory, i.e., the cross-sectional stiffness matrix and stress-strain-displacement recovery relations, are obtainable as closed-form analytical expressions. These results, coupled with the VAM-based beam analysis being devoid of ad hoc assumptions, culminate in what is expected to be of significance when formulating a general oblique cross-sectional analysis for beams with anisotropic material and initial curvature/twist, the detailed treatment of which will be alluded to in a later paper.
Friction Self-Piercing Riveting of Aluminum Alloy AA6061-T6 to Magnesium Alloy AZ31B
Authors: Li YongBing , Wei ZeYu , Wang ZhaoZhao , Li YaTing
Published: September 2013

Implementation of lightweight low-ductility materials such as aluminum alloys, magnesium alloys and composite materials has become urgently needed for automotive manufacturers to improve the competitiveness of their products. However, hybrid use of these materials poses big challenges to traditional joining process. Self-piercing riveting (SPR) is currently the most popular technique for joining dissimilar materials and has been widely used in joining all-aluminum and multimaterial vehicle bodies. However, in riveting magnesium alloys, cracks always occur for its low ductility. In this paper, a hybrid joining process named friction self-piercing riveting (F-SPR), which combines mechanical joining mechanism of SPR with solid-state joining mechanism of friction stir spot welding (FSSW) by making rivet rotating at high speed in riveting process, was proposed aiming at joining the low-ductility materials. The effectiveness of the F-SPR process was validated via riveting 1 mm thick AA6061-T6 and 2 mm thick AZ31B. The results showed that the F-SPR process could significantly improve the rivetability of magnesium alloys, and greatly increase the joint strength, comparing with the traditional SPR process.
A Novel Magnetic Stimulator Using Parallel Excited Coils and Capable of High Frequency Stimulation
Authors: Wankhar Syrpailyne , Devasahayam Suresh , Babu Srinivasa
Published: September 2013

Magnetic stimulators are used for transcranial and peripheral stimulation of nerves for diagnostic, therapeutic, and research purposes. Stimulation is achieved by generating a rapidly changing magnetic field to induce a current at the nerve of interest. Effective nerve stimulation requires a current transient of about 108A/s. This current is obtained by switching the current through a thyristor or an insulated gate bipolar transistor (IGBT). Insulated gate bipolar transistors have better turn off characteristics than thyristors. Due to the large currents, fast switching, and inductive load required in magnetic stimulators, spike voltages can occur and cause device damage. Therefore, they require elaborate protection circuitry. Contemporary magnetic stimulators are large, bulky, and give a current wave that is constrained by the device characteristics rather than decided by physiology. Recent instruments using IGBTs have addressed this question. However, the IGBTs require special considerations to protect them against damage. No magnetic stimulators reported so far can stimulate at rates greater than 60 Hz (Magstim Rapid2, two linked stimulators). A novel magnetic stimulator design is presented in this paper which uses a set of stacked coils driven by independent but synchronized electronic circuits to distribute the current so that only a fraction of the required current flows through any given circuit element. The coils can be arranged in several different geometries, depending on the location and shape of the nerves to be stimulated. While such paralleling of coils and control circuits is not so important for the thyristor circuit design, in the case of the IGBT design it allows the use of smaller IGBTs and better transient control. The design of the coils and independent excitation improves the current control and the magnetic field that is generated. The result is a portable instrument with well controlled rectangular pulse shapes. This stimulator is also capable of much higher frequencies (tested up to 100 Hz) than previously reported. Experimental tests have been compared with the biophysical analysis of stimulation with this instrument. Peripheral nerve stimulation and the elicited compound muscle action potential was used to validate the instrument. The instrument has been tested for the controlled recruitment of a compound nerve at up to 100 Hz. In this paper we present a portable magnetic stimulator capable of high frequency stimulation and rectangular stimulation pulse. These features should give fresh momentum to the use of magnetic stimulation in neurological investigations and interventions. In particular, we expect that it will find wide clinical use such as in pediatric neurology, psychiatry, and neuromodulation.
Microstructure-Sensitive Fatigue Modeling of AISI 4140 Steel
Authors: Jordon J. B. , Horstemeyer M. F.
Published: September 2013

A microstructure-based fatigue model is employed to predict fatigue damage in 4140 steel. Fully reversed, strain control fatigue tests were conducted at various strain amplitudes and scanning electron microscopy was employed to establish structure-property relations between the microstructure and cyclic damage. Fatigue cracks were found to initiate from particles near the free surface of the specimens. In addition, fatigue striations were found to originate from these particles and grew radially outward. The fatigue model used in this study captured the microstructural effects and mechanics of nucleation and growth observed in this ferrous metal. Good correlation of the number of cycles to failure between the experimental results and the model were achieved. Based on analysis of the mechanical testing, fractography and modeling, the fatigue life of the 4140 steel is estimated to comprise mainly of small crack growth in the low cycle regime and crack incubation in the high cycle fatigue regime.
Mucosal Immunization with High-Mobility Group Box 1 in Chitosan Enhances DNA Vaccine-Induced Protection against Coxsackievirus B3-Induced Myocarditis
Authors: Wang Maowei , Yue Yan , Dong Chunsheng , Li Xiaoyun , Xu Wei , Xiong Sidong
Published: September 2013

Coxsackievirus B3 (CVB3), a small single-stranded RNA virus, belongs to thePicornaviridaefamily. Its infection is the most common cause of myocarditis, with no vaccine available. Gastrointestinal mucosa is the major entry port for CVB3; therefore, the induction of local immunity in mucosal tissues may help control initial viral infections and alleviate subsequent myocardial injury. Here we evaluated the ability of high-mobility group box 1 (HMGB1) encapsulated in chitosan particles to enhance the mucosal immune responses induced by the CVB3-specific mucosal DNA vaccine chitosan-pVP1. Mice were intranasally coimmunized with 4 doses of chitosan-pHMGB1 and chitosan-pVP1 plasmids, at 2-week intervals, and were challenged with CVB3 4 weeks after the last immunization. Compared with chitosan-pVP1 immunization alone, coimmunization with chitosan-pHMGB1 significantly (P< 0.05) enhanced CVB3-specific fecal secretory IgA levels and promoted mucosal T cell immune responses. In accordance, reduced severity of myocarditis was observed in coimmunized mice, as evidenced by significantly (P< 0.05) reduced viral loads, decreased myocardial injury, and increased survival rates. Flow cytometric analysis indicated that HMGB1 enhanced dendritic cell (DC) recruitment to mesenteric lymph nodes and promoted DC maturation, which might partly account for its mucosal adjuvant effect. This strategy may represent a promising approach to candidate vaccines against CVB3-induced myocarditis.
Diversity of Methicillin-Resistant Staphylococcus aureus Strains Isolated from Residents of 26 Nursing Homes in Orange County, California
Authors: Hudson Lyndsey O. , Reynolds Courtney , Spratt Brian G. , Enright Mark C. , Quan Victor , Kim Diane , Hannah Paul , Mikhail Lydia , Alexander Richard , Moore Douglas F. , Godoy Daniel , Bishop Cynthia J. , Huang Susan S.
Published: September 2013

Nursing homes represent a unique and important methicillin-resistant
Staphylococcus aureus
(MRSA) reservoir. Not only are strains imported from hospitals and the community, strains can be transported back into these settings from nursing homes. Since MRSA bacteria are prevalent in nursing homes and yet relatively poorly studied in this setting, a multicenter, regional assessment of the frequency and diversity of MRSA in the nursing home reservoir was carried out and compared to that of the MRSA from hospitals in the same region. The prospective study collected MRSA from nasal swabbing of residents of 26 nursing homes in Orange County, California, and characterized each isolate by
spa
typing. A total of 837 MRSA isolates were collected from the nursing homes. Estimates of admission prevalence and point prevalence of MRSA were 16% and 26%, respectively. The
spa
type genetic diversity was heterogeneous between nursing homes and significantly higher overall (77%) than the diversity in Orange County hospitals (72%). MRSA burden in nursing homes appears largely due to importation from hospitals. As seen in Orange County hospitals, USA300 (sequence type 8 [ST8]/t008), USA100 (ST5/t002), and a USA100 variant (ST5/t242) were the dominant MRSA clones in Orange County nursing homes, representing 83% of all isolates, although the USA100 variant was predominant in nursing homes, whereas USA300 was predominant in hospitals. Control strategies tailored to the complex problem of MRSA transmission and infection in nursing homes are needed in order to minimize the impact of this unique reservoir on the overall regional MRSA burden.
Baculovirus F-Box Protein LEF-7 Modifies the Host DNA Damage Response To Enhance Virus Multiplication
Authors: Mitchell Jonathan K. , Byers Nathaniel M. , Friesen Paul D.
Published: September 2013

The DNA damage response (DDR) of a host organism represents an effective antiviral defense that is frequently manipulated and exploited by viruses to promote multiplication. We report here that the large DNA baculoviruses, which require host DDR activation for optimal replication, encode a conserved replication factor, LEF-7, that manipulates the DDR via a novel mechanism. LEF-7 suppresses DDR-induced accumulation of phosphorylated host histone variant H2AX (γ-H2AX), a critical regulator of the DDR. LEF-7 was necessary and sufficient to block γ-H2AX accumulation caused by baculovirus infection or DNA damage induced by means of pharmacological agents. Deletion of LEF-7 from the baculovirus genome allowed γ-H2AX accumulation during virus DNA synthesis and impaired both very late viral gene expression and production of infectious progeny. Thus, LEF-7 is essential for efficient baculovirus replication. We determined that LEF-7 is a nuclear F-box protein that interacts with host S-phase kinase-associated protein 1 (SKP1), suggesting that LEF-7 acts as a substrate recognition component of SKP1/Cullin/F-box (SCF) complexes for targeted protein polyubiquitination. Site-directed mutagenesis demonstrated that LEF-7's N-terminal F-box is necessary for γ-H2AX repression and
Autographa californica
multiple nucleopolyhedrovirus (AcMNPV) replication events. We concluded that LEF-7 expedites virus replication most likely by selective manipulation of one or more host factors regulating the DDR, including γ-H2AX. Thus, our findings indicate that baculoviruses utilize a unique strategy among viruses for hijacking the host DDR by using a newly recognized F-box protein.
Lower extremity performance following ACL rehabilitation in the KANON-trial: impact of reconstruction and predictive value at 2 and 5 years
Authors: Ericsson Ylva B , Roos Ewa M , Frobell Richard B
Published: September 2013

Background

The additional effect of anterior cruciate ligament (ACL) reconstruction on muscle strength and physical performance after a structured exercise programme is not well understood.

Objectives

To investigate and compare muscle strength and physical performance test results after a structured exercise programme, in young active adults with acute ACL injury, between those treated with and without ACL reconstruction (ACLR) and to evaluate these test results as predictors of clinical outcomes 2 and 5 years after injury.

Study design

Prospective cohort study.

Methods

In a treatment randomised controlled trial of acute ACL injury (the KANON-study), 87/121 young active adults underwent two muscle strength tests and five physical performance tests after a structured exercise programme (median 37 (IQR 24) weeks after injury). Results were presented and compared as limb symmetry indices (LSI); endpoints in predictive analyses were having a delayed ACLR over the first 5 years and self-reported knee function (Knee injury and Osteoarthritis Outcome Score; KOOS4) at 2 and 5 years.

Results

Overall, 74–95% of patients had LSI≥90% in the individual tests, with no difference between treatment groups (p=0.08–0.92). Results of the one-leg rise tests predicted KOOS4at 2 and 5 years (R2=0.25 and 0.24, p=0.001 and 0.002) and vertical hop results predicted having a delayed ACLR over a 5-year course after injury (p=0.048) in those starting with exercise alone (n=21).

Conclusions

After an acute ACL tear, the majority of young active adults regain physical performance and muscle strength after a structured exercise programme, with or without surgical reconstruction. Poor physical performance at the end of rehabilitation predicted worse patient-reported outcomes at 2 and 5 years regardless of treatment.

Registration number:

ISRCTN84752559.
AN INTRODUCTION TO WELL-POSEDNESS AND FREE-EVOLUTION
Authors: HILDITCH DAVID
Published: September 2013

These lecture notes accompany two classes given at the NRHEP2 school. In the first lecture I introduce the basic concepts used for analyzing well-posedness, that is the existence of a unique solution depending continuously on given data, of evolution partial differential equations. I show how strong hyperbolicity guarantees well-posedness of the initial value problem. Symmetric hyperbolic systems are shown to render the initial boundary value problem well-posed with maximally dissipative boundary conditions. I discuss the Laplace–Fourier method for analyzing the initial boundary value problem. Finally, I state how these notions extend to systems that are first-order in time and second-order in space. In the second lecture I discuss the effect that the gauge freedom of electromagnetism has on the PDE status of the initial value problem. I focus on gauge choices, strong-hyperbolicity and the construction of constraint preserving boundary conditions. I show that strongly hyperbolic pure gauges can be used to build strongly hyperbolic formulations. I examine which of these formulations is additionally symmetric hyperbolic and finally demonstrate that the system can be made boundary stable.
DEALING WITH VARIABILITY WHEN RECOGNIZING USER'S PERFORMANCE IN NATURAL 3D GESTURE INTERFACES
Authors: SOREL ANTHONY , KULPA RICHARD , BADIER EMMANUEL , MULTON FRANCK
Published: September 2013

Recognition of natural gestures is a key issue in many applications including videogames and other immersive applications. Whatever is the motion capture device, the key problem is to recognize a motion that could be performed by a range of different users, at an interactive frame rate. Hidden Markov Models (HMM) that are commonly used to recognize the performance of a user however rely on a motion representation that strongly affects the overall recognition rate of the system. In this paper, we propose to use a compact motion representation based on Morphology-Independent features and we evaluate its performance compared to classical representations. When dealing with 15 very similar upper limb motions, HMM based on Morphology-Independent features yield significantly higher recognition rate (84.9%) than classical Cartesian or angular data (70.4% and 55.0%, respectively). Moreover, when the unknown motions are performed by a large number of users who have never contributed to the learning process, the recognition rate of Morphology-Independent input feature only decreases slightly (down to 68.2% for a HMM trained with the motions of only one subject) compared to other features (25.3% for Cartesian features and 17.8% for angular features in the same conditions). The method is illustrated through an interactive demo in which three virtual humans have to interactively recognize and replay the performance of the user. Each virtual human is associated with a HMM recognizer based on the three different input features.
Stationary radiative transfer with vanishing absorption
Authors: Egger Herbert , Schlottbom Matthias
Published: September 2013

We investigate the unique solvability of radiative transfer problems without strictly positive lower bounds on the absorption and scattering parameters. The analysis is based on a reformulation of the transfer equation as a mixed variational problem with penalty term for which we establish the well-posedness. We also prove stability of the solution with respect to perturbations in the parameters. This allows to approximate stationary radiative transfer problems by even-parity formulations even in the case of vanishing absorption. The mixed variational framework used for the analysis also enables a systematic investigation of discretization obtained by Galerkin methods. We show that, in contrast to the full problem, the widely used PN-approximations, and discretizations based on these, are not stable in the case of vanishing absorption. Some consequences and possible remedies yielding stable approximations are discussed.
Existence and approximation of a mixed formulation for thin film magnetization problems in superconductivity
Authors: Barrett John W. , Prigozhin Leonid
Published: September 2013

We recall a recently introduced mixed formulation of thin film magnetization problems for type-II superconductors written in terms of two variables, the electric field and the magnetization function, see [Electric field formulation for thin film magnetization problems, Supercond. Sci. Technol.25 (2012) 104002]. A finite element approximation, [Formula: see text], based on this mixed formulation, involving the lowest-order Raviart–Thomas element for approximating the electric field, was also introduced in [Electric field formulation for thin film magnetization problems, Supercond. Sci. Technol.25 (2012) 104002]. Here h, τ are the spatial and temporal discretization parameters, and [Formula: see text] with p-1 the value of power in the current–voltage relation characterizing the superconducting material. In this paper, we establish well-posedness of [Formula: see text], and prove convergence of the unique solution of [Formula: see text] to a solution of the power law model ( Q r), for a fixed r > 1, as h, τ → 0. In addition, we prove convergence of a solution of ( Q r) to a solution of the critical state model (Q), as r → 1. Hence, we prove existence of solutions to ( Q r), for a fixed r > 1, and (Q). Finally, numerical experiments are presented.
DESALINATION BY CAPACITIVE DEIONIZATION WITH CARBON-BASED MATERIALS AS ELECTRODE: A REVIEW
Authors: HUANG WEI , ZHANG YIMIN , BAO SHENXU , SONG SHAOXIAN
Published: September 2013

Capacitive deionization (CDI) is a recently developed electrosorption technology for deionization using porous electrodes. The electrode materials play an important role in the efficiency. This paper highlights the current research status of carbon-based materials as the electrode and the adsorption models in the CDI. It includes the types and performances of carbon-based materials and the main influencing factors of the desalination characteristics. Also, operating parameters such as charging voltage, flow rate, concentration of feed solution, treating time and temperature are summarized.
CHARACTERIZING FLUORESCENCE LIFETIME OF NAD(P)H IN HUMAN LEUKEMIC MYELOID CELLS AND MONONUCLEAR CELLS
Authors: LIN LI-SHENG , LIU LI-NA , HUANG HUI-FANG , CHEN YUAN-ZHONG , LI BU-HONG , HUANG ZHENG
Published: September 2013

The aim of this ex vivo study was to explore the potential of using the fluorescence lifetime of intracellular reduced nicotinamide adenine dinucleotide (phosphate) (NAD(P)H) as a label-free indicator to characterize the differences between human leukemic myeloid cells and normal mononuclear cells (MNC). The steady-state and time-resolved autofluorescence of two human leukemic myeloid cell lines (K562, HL60) and MNC were measured by a spectrofluorimeter. According to excitation–emission matrix (EEM) analysis, the optimal emission of NAD(P)H in these cells suspensions occurred at 445 nm. Furthermore, the fluorescence lifetimes of NAD(P)H in leukemic myeloid cells and MNC were determined by fitting the time-resolved autofluorescence data. The mean fluorescence lifetimes of NAD(P)H in K562, HL60, and MNC cells were 5.57 ± 1.19, 4.45 ± 0.71, and 7.31 ± 0.60 ns, respectively. There was a significant difference in the mean lifetime of NAD(P)H between leukemic myeloid cells and MNC (p < 0.05). The difference was essentially caused by the change in relative concentration of free and protein-bound NAD(P)H. This study suggests that the mean fluorescence lifetime of NAD(P)H might be a potential label-free indicator for differentiating leukemic myeloid cells from MNC.
DOX-CONJUGATED HIGH-QUALITY AgZnInS QDs FOR REVERSAL OF MULTIDRUG RESISTANCE
Authors: QU LINGZHI , DENG DAWEI , WANG JIE , GU YUEQING
Published: September 2013

The synthesis of water-soluble quantum dots (QDs) has recently received extensive attention due to noninvasive detection of biological information in living subjects. In this paper, high-quality water-soluble (cadmium-free) quaternary AgZnInS QDs have been successfully synthesized using a green synthetic route. The as-prepared QDs exhibit tunable photoluminescence (PL) emission between 521 and 658 nm. Secondly, multidrug resistance (MDR) is a major impediment to the effective cancer chemotherapy. DOX, a widely used antitumor drug was modified on the surface of the QDs in this study. It, therefore, significantly enhanced the cytotoxicity of DOX to MDR cancer cells as the QDs could bring the DOX to nucleus.
3D imaging of the mitochondrial redox state of rat hearts under normal and fasting conditions
Authors: Xu He N. , Zhou Rong , Moon Lily , Feng Min , Li Lin Z.
Published: September 2013

The heart requires continuous ATP availability that is generated in the mitochondria. Although studies using the cell culture and perfused organ models have been carried out to investigate the biochemistry in the mitochondria in response to a change in substrate supply, mitochondrial bioenergetics of heart under normal feed or fasting conditions has not been studied at the tissue level with a sub-millimeter spatial resolution either in vivo or ex vivo. Oxidation of many food-derived metabolites to generate ATP in the mitochondria is realized through the NADH/NAD+couple acting as a central electron carrier. We employed the Chance redox scanner — the low-temperature fluorescence scanner to image the three-dimensional (3D) spatial distribution of the mitochondrial redox states in heart tissues of rats under normal feeding or an overnight starvation for 14.5 h. Multiple consecutive sections of each heart were imaged to map three redox indices, i.e., NADH, oxidized flavoproteins (Fp, including flavin adenine dinucleotide (FAD)) and the redox ratio NADH/Fp. The imaging results revealed the micro-heterogeneity and the spatial distribution of these redox indices. The quantitative analysis showed that in the fasted hearts the standard deviation of both NADH and Fp, i.e., SD_NADH and SD_Fp, significantly decreased with a p value of 0.032 and 0.045, respectively, indicating that the hearts become relatively more homogeneous after fasting. The fasted hearts contained 28.6% less NADH (p = 0.038). No significant change in Fp was found (p = 0.4). The NADH/Fp ratio decreased with a marginal p value (0.076). The decreased NADH in the fasted hearts is consistent with the cardiac cells' reliance of fatty acids consumption for energy metabolism when glucose becomes scarce. The experimental observation of NADH decrease induced by dietary restriction in the heart at tissue level has not been reported to our best knowledge. The Chance redox scanner demonstrated the feasibility of 3D imaging of the mitochondrial redox state in the heart and provides a useful tool to study heart metabolism and function under normal, dietary-change and pathological conditions at tissue level.
A Paradigm for Endosymbiotic Life: Cell Differentiation of Rhizobium Bacteria Provoked by Host Plant Factors
Authors: Kondorosi Eva , Mergaert Peter , Kereszt Attila
Published: September 2013

Symbiosis between Rhizobium bacteria and legumes leads to the formation of the root nodule. The endosymbiotic bacteria reside in polyploid host cells as membrane-surrounded vesicles where they reduce atmospheric nitrogen to support plant growth by supplying ammonia in exchange for carbon sources and energy. The morphology and physiology of endosymbionts, despite their common function, are highly divergent in different hosts. In galegoid plants, the endosymbionts are terminally differentiated, uncultivable polyploid cells, with remarkably elongated and even branched Y-shaped cells. Bacteroid differentiation is controlled by host peptides, many of which have antibacterial activity and require the bacterial function of BacA. Although the precise and combined action of several hundred host peptides and BacA has yet to be discovered, similarities, especially to certain insect-bacterium symbioses involving likewise host peptides for manipulation of endosymbionts, suggest convergent evolution. Rhizobium-legume symbiosis provides a rich source of information for understanding host-controlled endosymbiotic life in eukaryotic cells.
Experimental Approaches for Defining Functional Roles of Microbes in the Human Gut
Authors: Dantas Gautam , Sommer Morten O.A. , Degnan Patrick H. , Goodman Andrew L.
Published: September 2013

The complex and intimate relationship between humans and their gut microbial communities is becoming less obscure, due in part to large-scale gut microbial genome-sequencing projects and culture-independent surveys of the composition and gene content of these communities. These studies build upon, and are complemented by, experimental efforts to define underlying mechanisms of host-microbe interactions in simplified model systems. This review highlights the intersection of these approaches. Experimental studies now leverage the advances in high-throughput DNA sequencing that have driven the explosion of microbial genome and community profiling projects, and the loss-of-function and gain-of-function strategies long employed in model organisms are now being extended to microbial genes, species, and communities from the human gut. These developments promise to deepen our understanding of human gut host–microbiota relationships and are readily applicable to other host-associated and free-living microbial communities.
Vitamin D and the heart
Authors: Gardner David G. , Chen Songcang , Glenn Denis J.
Published: September 2013

Vitamin D receptors (VDR) are found in cells throughout the cardiovascular system. A variety of experimental studies indicate that the liganded VDR may play an important role in controlling cardiac hypertrophy and fibrosis, regulating blood pressure, and suppressing the development of atherosclerosis. Some, but not all, observational studies in humans provide support for these experimental findings, raising the possibility that vitamin D or its analogs might prove useful therapeutically in the prevention or treatment of cardiovascular disease.
The von Hippel-Lindau Chuvash mutation in mice causes carotid-body hyperplasia and enhanced ventilatory sensitivity to hypoxia
Authors: Slingo Mary E. , Turner Philip J. , Christian Helen C. , Buckler Keith J. , Robbins Peter A.
Published: September 2013

The hypoxia-inducible factor (HIF) family of transcription factors coordinates diverse cellular and systemic responses to hypoxia. Chuvash polycythemia (CP) is an autosomal recessive disorder in humans in which there is impaired oxygen-dependent degradation of HIF, resulting in long-term systemic elevation of HIF levels at normal oxygen tensions. CP patients demonstrate the characteristic features of ventilatory acclimatization to hypoxia, namely, an elevated baseline ventilation and enhanced acute hypoxic ventilatory response (AHVR). We investigated the ventilatory and carotid-body phenotype of a mouse model of CP, using whole-body plethysmography, immunohistochemistry, and electron microscopy. In keeping with studies in humans, CP mice had elevated ventilation in euoxia and a significantly exaggerated AHVR when exposed to 10% oxygen, with or without the addition of 3% carbon dioxide. Carotid-body immunohistochemistry demonstrated marked hyperplasia of the oxygen-sensing type I cells, and the cells themselves appeared enlarged with more prominent nuclei. This hypertrophy was confirmed by electron microscopy, which also revealed that the type I cells contained an increased number of mitochondria, enlarged dense-cored vesicles, and markedly expanded rough endoplasmic reticulum. The morphological and ultrastructural changes seen in the CP mouse carotid body are strikingly similar to those observed in animals exposed to chronic hypoxia. Our study demonstrates that the HIF pathway plays a major role, not only in regulating both euoxic ventilatory control and the sensitivity of the response to hypoxia, but also in determining the morphology of the carotid body.
Influences of premotoneuronal command statistics on the scaling of motor output variability during isometric plantar flexion
Authors: Watanabe Renato N. , Magalhães Fernando H. , Elias Leonardo A. , Chaud Vitor M. , Mello Emanuele M. , Kohn André F.
Published: September 2013

This study focuses on neuromuscular mechanisms behind ankle torque and EMG variability during a maintained isometric plantar flexion contraction. Experimentally obtained torque standard deviation (SD) and soleus, medial gastrocnemius, and lateral gastrocnemius EMG envelope mean and SD increased with mean torque for a wide range of torque levels. Computer simulations were performed on a biophysically-based neuromuscular model of the triceps surae consisting of premotoneuronal spike trains (the global input, GI) driving the motoneuron pools of the soleus, medial gastrocnemius, and lateral gastrocnemius muscles, which activate their respective muscle units. Two types of point processes were adopted to represent the statistics of the GI: Poisson and Gamma. Simulations showed a better agreement with experimental results when the GI was modeled by Gamma point processes having lower orders (higher variability) for higher target torques. At the same time, the simulations reproduced well the experimental data of EMG envelope mean and SD as a function of mean plantar flexion torque, for the three muscles. These results suggest that the experimentally found relations between torque-EMG variability as a function of mean plantar flexion torque level depend not only on the intrinsic properties of the motoneuron pools and the muscle units innervated, but also on the increasing variability of the premotoneuronal GI spike trains when their mean rates increase to command a higher plantar flexion torque level. The simulations also provided information on spike train statistics of several hundred motoneurons that compose the triceps surae, providing a wide picture of the associated mechanisms behind torque and EMG variability.
Purinergic modulation of norepinephrine release and uptake in rat brain cortex: contribution of glial cells
Authors: Pinho Diana , Quintas Clara , Sardo Filipa , Cardoso Teresa Magalhães , Queiroz Glória
Published: September 2013

The pathogenesis of psychiatric and neurodegenerative diseases is often associated with a deregulation of noradrenergic transmission. Considering the potential involvement of purinergic signaling in the modulation of noradrenergic transmission in the brain cortex, this study aimed to identify the P2Y receptor subtypes involved in the modulation of neuronal release and neuronal/glial uptake of norepinephrine. Electrical stimulation (100 pulses at 5 Hz) of rat cortical slices induced norepinephrine release that was inhibited by ATP and ADP (0.01–1 mM), adenosine 5′- O-(2-thiodiphosphate) (ADPβS, 0.03–0.3 mM), and UDP (0.1–1 mM). The effect of ADPβS was mediated by P2Y1receptors and possibly by A1/P2Y1heterodimers since it was attenuated by the A1receptor antagonist DPCPX and by the P2Y1receptor antagonist MRS 2500 but was resistant to the effect of adenosine deaminase (ADA). UDP inhibited norepinephrine release through activation of P2Y6receptors, an effect that was abolished by the P2Y6receptor antagonist MRS 2578 and by DPCPX, indicating that it depends on the formation and/or release of adenosine and activation of A1receptors. Supporting this hypothesis, the inhibitory effect of UDP was also prevented by inhibition of ectonucleotidases, by ADA and was attenuated by the inhibitor of nucleoside transporter 6-[(4-nitrobenzyl)thio]-9-β-d-ribofuranosylpurine (NBTI). Additionally, the inhibitory effect of UDP was attenuated when norepinephrine uptake 1 or 2 was inhibited. In astroglial cultures, ADPβS and UDP increased norepinephrine uptake mainly by activation of P2Y1and P2Y6receptors, respectively. The results indicate that neuronal and glial P2Y1and P2Y6receptors may represent new targets of intervention to regulate noradrenergic transmission in CNS diseases.
Graphs Whose Certain Polynomials Have Few Distinct Roots
Authors: Alikhani Saeid
Published: September 2013

Let G=(V,E) be a simple graph. Graph polynomials are a well-developed area useful for analyzing properties of graphs. We consider domination polynomial, matching polynomial, and edge cover polynomial of G. Graphs which their polynomials have few roots can sometimes give surprising information about the structure of the graph. This paper is primarily a survey of graphs whose domination polynomial, matching polynomial, and edge cover polynomial have few distinct roots. In addition, some new unpublished results and questions are concluded.
Discoloration of Indigo Carmine Using Aqueous Extracts from Vegetables and Vegetable Residues as Enzyme Sources
Authors: Solís A. , Perea F. , Solís M. , Manjarrez N. , Pérez H. I. , Cassani J.
Published: September 2013

Several vegetables and vegetable residues were used as sources of enzymes capable to discolor indigo carmine (IC), completely or partially. Complete discoloration was achieved with aqueous extracts of green pea seeds and peels of green pea, cucumber, and kohlrabi, as well as spring onion leaves. The source of polyphenol oxidase (PPO), pH, time, and aeration is fundamental for the discoloration process catalyzed by PPO. The PPO present in the aqueous extract of green pea seeds was able to degrade 3,000 ppm of IC at a pH of 7.6 and magnetic stirring at 1,800 rpm in about 36 h. In addition, at 1,800 rpm and a pH of 7.6, this extract discolored 300 ppm of IC in 1:40 h; in the presence of 10% NaCl, the discoloration was complete in 5:50 h, whereas it was completed in 4:30 h with 5% NaCl and 2% laundry soap.
Two Live Births following Robotic-Assisted Abdominal Cerclage in Nonpregnant Women
Authors: Göçmen Ahmet , Şanlıkan Fatih
Published: September 2013

Introduction. To report the robotic-assisted abdominal cerclage performed in two nonpregnant women and the success of live birth outcomes.Presentation of Cases. A 36-year-old woman with a complaint of recurrent second trimester pregnancy losses and a 35-year-old patient with a complaint of preterm deliveries and cervical insufficiency underwent robotic assisted abdominal cervicoisthmic cerclage placement in nonpregnant period. The two patients had spontaneous pregnancy after the robotic-assisted abdominal cerclage and delivered healthy infants.Discussion. The limitations of traditional laparoscopic abdominal cerclage have been accomplished with robotic surgery advantages especially intuitive movements and increased range of motion. There are only a few studies in the literature including robotic assisted abdominal cerclage in nonpregnant women, and only five successful live birth outcomes were reported. In this paper, we reported the sixth and seventh cases of achieved live pregnancy after robotic assisted abdominal cerclage in the literature.Conclusion. Robotic assisted abdominal cerclage is a good alternative surgical method with successful pregnancy outcomes.
The Investigation of Tramadol Dependence with No History of Substance Abuse: A Cross-Sectional Survey of Spontaneously Reported Cases in Guangzhou City, China
Authors: Zhang Haoran , Liu Zhimin
Published: September 2013

The study was to survey and assess the drug dependence and abuse potential of tramadol with no history of substance abuse. Subjects of tramadol dependence with no prior history of substance abuse were surveyed by interview. Physical dependence of tramadol was assessed using 10 items opiate withdrawal scale (OWS), and psychological dependence was assessed by Addiction Research Center Inventory—Chinese Version (ARCI-CV). Twenty-three male subjects (the median age was23.4±4.1years) referred to the addiction unit in Medical Hospital of Guangzhou with tramadol abuse problems were included in this cross-sectional study. The control group included 87 heroin addicts, 60 methamphetamine (MA) abusers, and 50 healthy men. The scores of OWS of tramadol were 0.83–2.30; the mean scores of identifying euphoric effects–MBG, sedative effects–PCAG, and psychotomimetic effects–LSD of ARCI were8.96±3.08,6.52±3.25, and6.65±2.50, respectively,F= 4.927,P<0.001. Scores of MBG scale in tramadol did not differ from those in heroin and MA groups (P>0.05) but were higher than those in healthy men (P<0.05). Tramadol with no history of substance abuse has a clear risk of producing high abuse potential under the long-term infrequent abuse and the high doses.
Full-Wave Analysis of Microstrip Antennas in Three-Layered Spherical Media
Authors: Yu Tao , Yin Chengyou
Published: September 2013

A model of three-layered spherical microstrip antenna has been analyzed based on Rao-Wilton-Glisson (RWG) triangular basis functions using mixed potential integral equation (MPIE). Firstly, the model of antenna and the dyadic Green’s function in spherical microstrip antennas are given at the beginning of this paper. Then, due to the infinite series convergence problem, asymptotic extraction approach is presented to accelerate the Green’s functions convergence speed when source and field points are located in the same layer and different layers. The convergence speed can be accelerated observably by using this method. Finally, in order to simplify impedance matrix elements calculation at the junction of the probe and patch, a novel division fashion of pair of triangles is adopted in this paper. The input impedance result obtained shows the validity and effectiveness of the analysis method comparing with published data.
Spatial and Temporal Trends in PM2.5Organic and Elemental Carbon across the United States
Authors: Hand J. L. , Schichtel B. A. , Malm W. C. , Frank N. H.
Published: September 2013

The rural/remote IMPROVE network (Interagency Monitoring of Protected Visual Environments) and the Environmental Protection Agency's urban Chemical Speciation Network have measured PM2.5organic (OC) and elemental carbon (EC) since 1989 and 2000, respectively. We aggregated OC and EC data from 2007 to 2010 at over 300 sites from both networks in order to characterize the spatial and seasonal patterns in rural and urban carbonaceous aerosols. The spatial extent of OC and EC was more regional in the eastern United States relative to more localized concentrations in the West. The highest urban impacts of OC and EC relative to background concentrations occurred in the West during fall and winter. Urban and rural carbonaceous aerosols experienced a large (although opposite) range in seasonality in the West compared to a much lower seasonal variability in the East. Long-term (1990–2010) trend analyses indicated a widespread decrease in rural TC (TC = OC + EC) across the country, with positive, though insignificant, trends in the summer and fall in the West. Short-term trends indicated that urban and rural TC concentrations have both decreased since 2000, with the strongest and more spatially homogeneous urban and rural trends in the West relative to the East.
Synthesis, Antimicrobial, and Anti-HIV1 Activity of Quinazoline-4(3H)-one Derivatives
Authors: Vijayakumar K. , Ahamed A. Jafar , Thiruneelakandan G.
Published: September 2013

The present investigation aims to synthesize 11 compounds of quinazoline-1 derivatives and to test their antimicrobial and anti-HIV1 activities. A quick-witted method was developed for the synthesis of novel substituted quinazolinone derivatives by summarizing diverse diamines with benzoxazine reactions, and it demonstrated the benefits of typical reactions, handy operation, and outstanding product yields. These compounds were confirmed by elemental analysis, I R, 1H NMR, 13C NMR, and mass spectra. Then antimicrobial and anti-HIV1 activities of the compounds were tested in-vitro. It was found that compounds 7–11 possessed a wide range of anti microbial and anti-HIV1 activity.
Preoperative Cardiac Variables of Diastolic Dysfunction and Clinical Outcomes in Lung Transplant Recipients
Authors: Yadlapati Ajay , Lynch Joseph P. , Saggar Rajan , Ross David , Belperio John A. , Weigt Stephen , Ardehali Abbas , Grogan Tristan , Yang Eric H. , Aboulhosn Jamil
Published: September 2013

Background. Orthotopic lung transplantation is now widely performed in patients with advanced lung disease. Patients with moderate or severe ventricular systolic dysfunction are typically excluded from lung transplantation; however, there is a paucity of data regarding the prognostic significance of abnormal left ventricular diastolic function and elevated pretransplant pulmonary pressures.Methods. We reviewed the characteristics of 111 patients who underwent bilateral and unilateral lung transplants from 200 to 2009 in order to evaluate the prognostic significance of preoperative markers of diastolic function, including invasively measured pulmonary capillary wedge pressure (PCWP) and echocardiographic variables of diastolic dysfunction including mitralA>EandA′>E′.Results. Out of 111 patients, 62 were male (56%) and average age was 54.0 ± 10.5 years. Traditional echocardiographic Doppler variables of abnormal diastolic function, includingA′>E′andA>E, did not predict adverse events (P=0.49). Mildly elevated pretransplant PCWP (16–20 mmHg) and moderately/severely elevated PCWP (>20 mmHg) were not associated with adverse clinical events after transplant (P=0.30). Additionally, all clinical endpoints did not show any statistical significance between the two groups.Conclusions. Pre-lung transplant invasive and echocardiographic findings of elevated pulmonary pressures and abnormal left ventricular diastolic function are not predictive of adverse posttransplant clinical events.
Balance Fatigue Design of Cast Steel Nodes in Tubular Steel Structures
Authors: Wang Libin , Jin Hui , Dong Haiwei , Li Jing
Published: September 2013

Cast steel nodes are being increasingly popular in steel structure joint application as their advanced mechanical performances and flexible forms. This kind of joints improves the structural antifatigue capability observably and is expected to be widely used in the structures with fatigue loadings. Cast steel node joint consists of two parts: casting itself and the welds between the node and the steel member. The fatigue resistances of these two parts are very different; the experiment results showed very clearly that the fatigue behavior was governed by the welds in all tested configurations. This paper focuses on the balance fatigue design of these two parts in a cast steel node joint using fracture mechanics and FEM. The defects in castings are simulated by cracks conservatively. The final crack size is decided by the minimum of 90% of the wall thickness and the value deduced by fracture toughness. The allowable initial crack size could be obtained through the integral of Paris equation when the crack propagation life is considered equal to the weld fatigue life; therefore, the two parts in a cast steel node joint will have a balance fatigue life.
Molecular Design and Applications of Self‐Assembling Surfactant‐Like Peptides
Authors: Tang Chengkang , Qiu Feng , Zhao Xiaojun
Published: September 2013

Self‐assembling surfactant‐like peptides have been explored as emerging nanobiomaterials in recent years. These peptides are usually amphiphilic, typically possessing a hydrophobic moiety and a hydrophilic moiety. The structural characteristics can promote many peptide molecules to self‐assemble into various nanostructures. Furthermore, properties of peptide molecules such as charge distribution and geometrical shape could also alter the formation of the self‐assembling nanostructures. Based on their diverse self‐assembling behaviours and nanostructures, self‐assembling surfactant‐like peptides exhibit great potentials in many fields, including membrane protein stabilization, drug delivery, and tissue engineering. This review mainly focuses on recent advances in studying self‐assembling surfactant‐like peptides, introducing their designs and the potential applications in nanobiotechnology.
Coverage Optimization Algorithm Based on Sampling for 3D Underwater Sensor Networks
Authors: Xiaoyu Du , Lijuan Sun , Linfeng Liu
Published: September 2013

We discuss the problem of maximizing the sensor field coverage for a specific number of sensors while minimizing the distance traveled by the sensor nodes. Thus, we define the movement task as an optimization problem that involves the adjustment of sensor node positions in a coverage optimization mission. We propose a coverage optimization algorithm based on sampling to enhance the coverage of 3D underwater sensor networks. The proposed coverage optimization algorithm is inspired by the simple random sampling in probability theory. The main objective of this study is to lessen computation complexity by dimension reduction, which is composed of two detailed steps. First, the coverage problem in 3D space is converted into a 2D plane for heterogeneous networks via sampling plane in the target 3D space. Second, the optimization in the 2D plane is converted into an optimization in a line segment by using the line sampling method in the sample plane. We establish a quadratic programming mathematical model to optimize the line segment coverage according to the intersection between sensing circles and line segments while minimizing the moving distance of the nodes. The intersection among sensors is decreased to increase the coverage rate, while the effective sensor positions are identified. Simulation results show the effectiveness of the proposed approach.