bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental and Numerical Studies of Vortex Induced Vibration on Cylinder
Authors: Mobassher Tofa M. , Maimun Adi , M. Ahmed Yasser , Jamei Saeed , Abyn Hassan
Published: March 2014

Study of vibrations due to vortex shedding (VIV) in the wake of a cylinder that is exposed to current or oscillatory flow is very important, especially for marine risers which are used to extract oil  and gas from the sea bed. The phenomenon of vortex induced vibration (VIV) has been one of the major concerns for hydrodynamic researchers due to its potential ability to cause severe fatigue damage. The hydrodynamics of VIV is very complex and still not fully understood. In this paper, some results (amplitude over diameter, lift and drag coefficients) of high Reynolds VIV experiments that are performed in UTM towing tank with an in-house test set-up are presented. A circular cylinder of 114 mm in diameter and 3 min length was towed at constant speed through the basin at Reynolds numbers up to 1.1x105. Model tests with a stationary cylinder and tests with a freely vibrating cylinder were carried out to investigate the influence of VIV on drag coefficient. Later these results are compared with results obtained through 3D numerical simulation, LES is used to solve turbulence flow. It was found that CFD results showed similar trends with experimental results. Results of this paper can be very important to design riser system  and future endeavor  to perform  similar kind of experiments. Successful numerical study of the VIV can also be fruitful for designing efficient VIV suppression devices.
An Innovative Vertical Axis Current Turbine Design for Low Current Speed
Authors: Behrouzi Fatemeh , Maimun Adi , Nakisa Mehdi , Hanafi Mohamad , Jaswar Jaswar
Published: March 2014

This article presents the new innovative concept for optimal design of Vertical Axis Current Turbines (VACT) applicable in low current speed which is being increasingly used to harness kinetic energy of water and convert it into other useful forms of energy as a clean and renewable energy. Widespread commercial acceptability of these turbo machines depends upon their efficiency. This largely depends upon the geometric features of the hydro turbines such as operation of designed system, joints, number and shape of blades and etc. The concept of VACT was proposed to provide a solution for the case of low current force inflow to vertical axis turbines. VACT has four suitable blades with flexible hinge joint to guide the water in come to reduce the drag force, light shaft and arms with stiff metal to make rigid and strong structure. The current study discusses the components of VAC turbine, rigidity of structure, performance, executive concept, efficiency, material, gearbox, environmental impacts and prevention of water corrosion. The new proposed innovative concept of VACT has flexible hinge connection for changing the blades directions automatically to reduce hydrodynamic drag and increase the hydrodynamic pressure to rotate the main shaft and enhance the efficiency as well. Main shaft connected to epicyclical gearbox to provide the higher torque for maximum electric power generation.
Investigation on Wear Behavior and Chip Formation During Up-Milling and Down-Milling Operations for Inconel 718
Authors: Hadi M. A. , Ghani J. A. , Che Haron C. H. , Kasim M. S.
Published: March 2014

A comprehensive study and FEM simulation of ball nose end milling on tool wear behavior and chip formation had been performed on Inconel 718 (nickle-based superalloy) under minimum quantity lubricant (MQL) condition. In this paper, the investigation was focusing on the comparison of up-milling and down-milling operations using a multi-layer TiAlN/AlCrN-coated carbide inserts. A various cutting parameters; depth of cut, feed rate and cutting speed were considered during the evaluation. The experimental results showed that down-milling operation has better results in terms of tool wear compared to up-milling operation. Chipping on cutting tool edge responsible to notch wear with prolong machining. It was observed that the chips formed in up-milling operation were segmented and continuous, meanwhile down-milling operation produced discontinuous type of chips.
Approximate Analytical Solutions of KdV and Burgers’ Equations via HAM and nHAM
Authors: Nazari Mojtaba , Baratie Vahid , Daniel David Vincent , Salah Faisal , Abdul Aziz Zainal
Published: March 2014

This article presents a comparative study of the accuracy between homotopy analysis method (HAM) and a new technique of homotopy analysis method (nHAM) for the Korteweg–de Vries (KdV) and Burgers’ equations. The resulted HAM and nHAM solutions at 8th-order and 6th-order approximations are then compared with that of the exact soliton solutions of KdV and Burgers’ equations, respectively. These results are shown to be in excellent agreement with the exact soliton solution. However, the result of HAM solution is ratified to be more accurate than the nHAM solution, which conforms to the existing finding.
The Influence Factor for the Successful Implementation of Cleaner Production: A Review
Authors: Yusup Muhamad Zaki , Wan Mahmood Wan Hasrulnizzam , Salleh Mohd Rizal , Muhamad Mohd Razali
Published: March 2014

Cleaner Production (CP) is an environmental management strategy that is being implemented based on social-technical approach. It has been proved to be adapted at every stage of the manufacturing process, particularly in establishing the green factory. Even so, the implementation performance of this practice is still depends on several critical factors to be successful. The review has disclosed that social responsiveness; legislation compliance’s and economic performance are the element that has a high influence level for the successful implementation of this practice. The ability to underline these elements has been seen able to assist manufacturers to identify the strength and weaknesses of the implementation process. This eventually motivates the manufacturer to develop a significant guideline in establishing the sustainable environmental practices and consequently increases the manufacturing performance and strengthens the ability to continuously compete in global markets.
Study on Trajectory Motion and Computational Analysis of Robot Manipulator
Authors: Umar Siti Nur Hanisah , Abu Bakar Elmi
Published: March 2014

The relation of arm and forearm for arm pitching a ball and bowling game, relation of rotating arm and the connecting rod for crankshaft and any other mechanical system will determine the performance of the system. To obtain the best performance of the system, the study of the dynamic mechanism of the system is essential. In order to study and analyze the dynamic interaction of each link for various applications, robot links manipulator is used as a simplified model for dynamic analysis. The dynamic mathematical equation of robot manipulator is derived by using the Lagrange equation. The elevation angle and angular velocity over time of link one and two is simulated using computerized algorithm. The trajectory motion of both links is illustrated and the relation between both links is determined. The results obtained are then compared with the SimMechanics model.
The Formulation of Ceramic Bodies using the Toba Volcanic Ash of Lenggong
Authors: Haron Hamdzun , Ayob Salwa
Published: March 2014

The amalgamation of science and art is indisputable in the production of ceramic clay bodies for the creation of an artwork. It covers all stages of the production process starting from the formulation of raw materials (clay) to the final glazed products. This research observes the transformation of the clay body formulation by using alternative silica from Toba volcanic ash. Malaysia is located outside the ring of fire, but through the archaeological findings, there are volcanic ash deposits found at several places such as in Kedah, Perak, Selangor and Pahang. From previous studies, it is proven that this volcanic ash originated from the volcanic eruption of Toba in northern Sumatra around 74,000 years ago. Among all of these findings, volcanic ash in which situated at Lenggong, Perak is considered as the most suitable for this research because it is categorized as a primary and through the laboratory studies that has been conducted, it is found that it has sufficient amount of silica to be used as alternative material in producing ceramic bodies. Silica is one of the main ingredients in a glass formation. In the production of porcelain bodies, silica has been used at a rate of 15% to 25%. The success in producing ceramic bodies using volcanic ash opens up possibilities for diversifying the products made from volcanic ash, a material which has been wasted before and this will reduce the cost of raw materials. At the same time it is considered as an innovation of ceramic product with the specialties of its own including the historical values that come through the transformation process of the body to the creation of ceramic works displayed at galleries.
Mg2+ block properties of triheteromeric GluN1–GluN2B–GluN2D NMDA receptors on neonatal rat substantia nigra pars compacta dopaminergic neurones
Authors: Huang Zhuo , Gibb Alasdair J.
Published: March 2014

Key points

NMDAR receptors (NMDARs) are tetrameric cation channels permeable to calcium and blocked by Mg2+.

Voltage‐dependent Mg2+ block of NMDARs is crucial to several forms of synaptic plasticity and to the integration of synaptic activity with neuronal activity. Although diheteromeric GluN1–GluN2A or GluN1–GluN2B NMDARs display stronger voltage‐dependent Mg2+ block than GluN1–GluN2C or GluN1–GluN2D NMDARs, the extracellular Mg2+ block properties for triheteromeric NMDARs are still elusive.

Here, we show that in dopaminergic neurones the voltage dependence of Mg2+ block is less steep than previously observed in hippocampus or cortex, consistent with the presence of triheteromeric GluN1–GluN2B–GluN2D NMDARs.

These results may help to understand the role of triheteromeric NMDARs in dopaminergic neurone synaptic plasticity and to inform simulations of dopaminergic neurone physiology.

Native NMDA receptors (NMDARs) are tetrameric channels formed by two GluN1 and two GluN2 subunits. So far, seven NMDARs subunits have been identified and they can form diheteromeric or triheteromeric NMDARs (more than one type of GluN2 subunit). Extracellular Mg2+ is an important regulator of NMDARs, and particularly the voltage dependence of Mg2+ block is crucial to the roles of NMDARs in synaptic plasticity and the integration of synaptic activity with neuronal activity. Although the Mg2+ block properties of diheteromeric NMDARs are fully investigated, properties of triheteromeric NMDARs are still not clear. Our previous data suggested that dopaminergic neurones expressed triheteromeric GluN1–GluN2B–GluN2D NMDARs. Here, using NMDARs in dopaminergic neurones from postnatal day 7 (P7) rats as a model system, we characterize the voltage‐dependent Mg2+ block properties of triheteromeric NMDARs. In control conditions, external Mg2+ significantly inhibits the whole cell NMDA‐evoked current in a voltage‐dependent manner with IC50 values of 20.9 μm, 53.3 μm and 173 μm at −90 mV, −70 mV and −50 mV, respectively. When the GluN2B‐selective antagonist ifenprodil was applied, the Mg2+ sensitivity of the residual NMDA‐mediated currents (which is mainly carried by GluN1–GluN2B–GluN2D NMDARs) is reduced to IC50 values of 45.9 μm (−90 mV), 104 μm (−70 mV) and 276 μm (−50 mV), suggesting that triheteromeric GluN1–GluN2B–GluN2D NMDARs have less affinity for external Mg2+ than GluN1–GluN2B receptors. In addition, fitting INMDA–V curves with a trapping Mg2+ block model shows the triheteromeric GluN1–GluN2B–GluN2D NMDARs have weaker voltage‐dependent Mg2+ block (δ = 0.56) than GluN1–GluN2B NMDARs. Finally, our concentration jump and single channel recordings suggest that GluN1–GluN2B–GluN2D rather than GluN1–GluN2D NMDARs are present. These data provide information relevant to Mg2+ block characteristics of triheteromeric NMDARs and may help to better understand synaptic plasticity, which is dependent on these triheteromeric NMDARs.
Modulation of ionotropic glutamate receptor function by vertebrate galectins
Authors: Copits Bryan A. , Vernon Claire G. , Sakai Ryuichi , Swanson Geoffrey T.
Published: March 2014

Key points

Lectins are a family of small evolutionarily conserved sugar‐binding proteins that regulate a diverse array of physiological processes ranging from immune system activation to cancer cell metastasis.

Ionotropic glutamate receptor function can be modulated by plant‐derived lectins, but the physiological relevance of this activity is unclear as no analogous function has been identified in animal lectins.

We found that a variety of vertebrate lectins, including human brain‐expressed galectin‐1, modulated glutamate receptor kinetics in a subunit and lectin‐dependent manner, which critically depended on complex oligosaccharide processing.

Galectin application slowed neuronal kainate receptor currents from nociceptive dorsal root ganglion neurons.

We propose that brain‐expressed galectins are potential endogenous modulators of neuronal glutamate receptors, which may play important roles in diseases of altered cellular excitability, such as epilepsy or chronic pain.

AMPA and kainate receptors are glutamate‐gated ion channels whose function is known to be altered by a variety of plant oligosaccharide‐binding proteins, or lectins, but the physiological relevance of this activity has been uncertain because no lectins with analogous allosteric modulatory effects have been identified in animals. We report here that members of the prototype galectin family, which are β‐galactoside‐binding lectins, exhibit subunit‐specific allosteric modulation of desensitization of recombinant homomeric and heteromeric AMPA and kainate receptors. Galectin modulation of GluK2 kainate receptors was dependent upon complex oligosaccharide processing of N‐glycosylation sites in the amino‐terminal domain and downstream linker region. The sensitivity of GluA4 AMPA receptors to human galectin‐1 could be enhanced by supplementation of culture media with uridine and N‐acetylglucosamine (GlcNAc), precursors for the hexosamine pathway that supplies UDP‐GlcNAc for synthesis of complex oligosaccharides. Neuronal kainate receptors in dorsal root ganglia were sensitive to galectin modulation, whereas AMPA receptors in cultured hippocampal neurons were insensitive, which could be a reflection of differential N‐glycan processing or receptor subunit selectivity. Because glycan content of integral proteins can be modified dynamically, we postulate that physiological or pathological conditions in the CNS could arise in which galectins alter excitatory neurotransmission or neuronal excitability through their actions on AMPA or kainate receptors.
Distinct Cytoplasmic Domains in Plexin-A4 Mediate Diverse Responses to Semaphorin 3A in Developing Mammalian Neurons
Authors: Mlechkovich Guy , Peng Sheng-Shiang , Shacham Vered , Martinez Edward , Gokhman Irena , Minis Adi , Tran Tracy S. , Yaron Avraham
Published: March 2014

Deletion analysis reveals how one neuronal guidance cue–receptor pair can produce either axonal retraction or dendritic branching.
Immune Variation
Authors: Zahn Laura
Published: March 2014

Consideration of cell type– and disease-associated environmental conditions is critical to connecting specific genetic variants to immune disorders.
Comparative Genomic Analysis of KPC-Encoding pKpQIL-Like Plasmids and Their Distribution in New Jersey and New York Hospitals
Authors: Chen Liang , Chavda Kalyan D. , Melano Roberto G. , Jacobs Michael R. , Koll Brian , Hong Tao , Rojtman Albert D. , Levi Michael H. , Bonomo Robert A. , Kreiswirth Barry N.
Published: March 2014

The global spread of
Klebsiella pneumoniae
carbapenemase (KPC) is predominately associated with
K. pneumoniae
strains genotyped as sequence type 258 (ST258). The first ST258-associated plasmid, pKpQIL, was described in Israel in 2006, but its history in the northeastern United States remains unknown. Six pKpQIL-like plasmids from four
K. pneumoniae
isolates (three ST258 and one ST234), one
Escherichia coli
isolate, and one
Enterobacter aerogenes
isolate, collected from 2003 to 2010 in New York (NY) and New Jersey (NJ) hospitals, were completely sequenced. The sequences and overall sizes of the six plasmids are highly similar to those of pKpQIL; the major difference is that five of six NJ/NY strains harbor
bla
KPC-2
, while pKpQIL contains
bla
KPC-3
. Moreover, a 26.7-kb fragment was inverted in pKpQIL-234 (from ST234
K. pneumoniae
), while a 14.5-kb region was deleted in pKpQIL-Ec (from ST131
E. coli
). PCR screening of 284 other clinical
K. pneumoniae
isolates identified 101 (35.6%) harboring pKpQIL-like plasmids from 9 of 10 surveyed hospitals, demonstrating the wide dissemination of pKpQIL in this region of endemicity. Among the positive isolates, 87.1% were typed as ST258 and 88.1% carried
bla
KPC-2
. The finding of pKpQIL-like plasmid in this study from strains that predate the initial report of KPC in Israel provides evidence that pKpQIL may have originated in the United States. Our findings demonstrate that pKpQIL plasmids are both spreading clonally in ST258 strains and spreading horizontally to different sequence types and species, further highlighting the clinical and public health concerns associated with carbapenem resistance.
Characterization of the Proliferating Cell Nuclear Antigen of Leishmania donovani Clinical Isolates and Its Association with Antimony Resistance
Authors: Tandon Rati , Chandra Sharat , Baharia Rajendra Kumar , Das Sanchita , Misra Pragya , Kumar Awanish , Siddiqi Mohammad Imran , Sundar Shyam , Dube Anuradha
Published: March 2014

Previously, through a proteomic analysis, proliferating cell nuclear antigen (PCNA) was found to be overexpressed in the sodium antimony gluconate (SAG)-resistant clinical isolate compared to that in the SAG-sensitive clinical isolate ofLeishmania donovani. The present study was designed to explore the potential role of the PCNA protein in SAG resistance inL. donovani. For this purpose, the protein was cloned, overexpressed, purified, and modeled. Western blot (WB) and real-time PCR (RT-PCR) analyses confirmed that PCNA was overexpressed by ≥3-fold in the log phase, stationary phase, and peanut agglutinin isolated procyclic and metacyclic stages of the promastigote form and by ∼5-fold in the amastigote form of the SAG-resistant isolate compared to that in the SAG-sensitive isolate.L. donovaniPCNA (LdPCNA) was overexpressed as a green fluorescent protein (GFP) fusion protein in a SAG-sensitive clinical isolate ofL. donovani, and modulation of the sensitivities of the transfectants to pentavalent antimonial (SbV) and trivalent antimonial (SbIII) drugs was assessedin vitroagainst promastigotes and intracellular (J774A.1 cell line) amastigotes, respectively. Overexpression of LdPCNA in the SAG-sensitive isolate resulted in an increase in the 50% inhibitory concentrations (IC50) of SbV(from 41.2 ± 0.6 μg/ml to 66.5 ± 3.9 μg/ml) and SbIII(from 24.0 ± 0.3 μg/ml to 43.4 ± 1.8 μg/ml). Moreover, PCNA-overexpressing promastigote transfectants exhibited less DNA fragmentation compared to that of wild-type SAG-sensitive parasites upon SbIIItreatment. In addition, SAG-induced nitric oxide (NO) production was found to be significantly inhibited in the macrophages infected with the transfectants compared with that in wild-type SAG-sensitive parasites. Consequently, we infer that LdPCNA has a significant role in SAG resistance inL. donovaniclinical isolates, which warrants detailed investigations regarding its mechanism.
Population Pharmacokinetics of Rifapentine and Desacetyl Rifapentine in Healthy Volunteers: Nonlinearities in Clearance and Bioavailability
Authors: Savic Radojka M. , Lu Yanhui , Bliven-Sizemore Erin , Weiner Marc , Nuermberger Eric , Burman William , Dorman Susan E. , Dooley Kelly E.
Published: March 2014

Rifapentine is under active investigation as a potent drug that may help shorten the tuberculosis (TB) treatment duration. A previous rifapentine dose escalation study with daily dosing indicated a possible decrease in bioavailability as the dose increased and an increase in clearance over time for rifapentine and its active metabolite, desacetyl rifapentine. This study aimed to assess the effects of increasing doses on rifapentine absorption and bioavailability and to evaluate the clearance changes over 14 days. A population analysis was performed with nonlinear mixed-effects modeling. Absorption, time-varying clearance, bioavailability, and empirical and semimechanistic autoinduction models were investigated. A one-compartment model linked to a transit compartment absorption model best described the data. The bioavailability of rifapentine decreased linearly by 2.5% for each 100-mg increase in dose. The autoinduction model suggested a dose-independent linear increase in clearance of the parent drug and metabolite over time from 1.2 and 3.1 liters · h
−1
, respectively, after a single dose to 2.2 and 5.0 liters · h
−1
, respectively, after 14 once-daily doses, with no plateau being reached by day 14. In clinical trial simulations using the final model, rifapentine demonstrated less-than-dose-proportional pharmacokinetics, but there was no plateau in exposures over the dose range tested (450 to 1,800 mg), and divided dosing increased exposures significantly. Thus, the proposed compartmental model incorporating daily dosing of rifapentine over a wide range of doses and time-related changes in bioavailability and clearance provides a useful tool for estimation of drug exposure that can be used to optimize rifapentine dosing for TB treatment. (This study has been registered at ClinicalTrials.gov under registration no. NCT01162486.)
Quantification of Cell-Associated Atazanavir, Darunavir, Lopinavir, Ritonavir, and Efavirenz Concentrations in Human Mononuclear Cell Extracts
Authors: Podany Anthony T. , Winchester Lee C. , Robbins Brian L. , Fletcher Courtney V.
Published: March 2014

An ultrasensitive assay utilizing high-pressure liquid chromatography and mass spectrometry detection was developed and validated for the quantification of the antiretrovirals atazanavir (ATV), darunavir (DRV), lopinavir (LPV), ritonavir (RTV), and efavirenz (EFV) in human mononuclear cell (MNC) extracts. The assay utilizes 20 μl of cellular extract that contains as few as 50,000 MNCs. The analytical range of the assay is 0.0200 to 10.0 fmol/μl for ATV, 0.0500 to 25.0 fmol/μl for DRV, LPV, and RTV, and 0.200 to 100 fmol/μl for EFV. The assay has proven to be a clinically useful tool for investigating antiretroviral drug concentrations in virologic sanctuaries where harvested cell numbers are extremely low. The assay provides a tool for investigators to explore the clinical pharmacology of strategies for prevention, treatment, and cure in pathophysiologically relevant sites.
Modulation of Alternaria infectoria Cell Wall Chitin and Glucan Synthesis by Cell Wall Synthase Inhibitors
Authors: Fernandes Chantal , Anjos Jorge , Walker Louise A. , Silva Branca M. A. , Cortes Luísa , Mota Marta , Munro Carol A. , Gow Neil A. R. , Gonçalves Teresa
Published: March 2014

The present work reports the effects of caspofungin, a β-1,3-glucan synthase inhibitor, and nikkomycin Z, an inhibitor of chitin synthases, on two strains of
Alternaria infectoria
, a melanized fungus involved in opportunistic human infections and respiratory allergies. One of the strains tested, IMF006, bore phenotypic traits that conferred advantages in resisting antifungal treatment. First, the resting cell wall chitin content was higher and in response to caspofungin, the chitin level remained constant. In the other strain, IMF001, the chitin content increased upon caspofungin treatment to values similar to basal IMF006 levels. Moreover, upon caspofungin treatment, the
FKS1
gene was upregulated in IMF006 and downregulated in IMF001. In addition, the resting β-glucan content was also different in both strains, with higher levels in IMF001 than in IMF006. However, this did not provide any advantage with respect to echinocandin resistance. We identified eight different chitin synthase genes and studied relative gene expression when the fungus was exposed to the antifungals under study. In both strains, exposure to caspofungin and nikkomycin Z led to modulation of the expression of class V and VII chitin synthase genes, suggesting its importance in the robustness of
A. infectoria
. The pattern of
A. infectoria
phagocytosis and activation of murine macrophages by spores was not affected by caspofungin. Monotherapy with nikkomycin Z and caspofungin provided only fungistatic inhibition, while a combination of both led to fungal cell lysis, revealing a strong synergistic action between the chitin synthase inhibitor and the β-glucan synthase inhibitor against this fungus.
2-Aminothiazolones as Anti-HIV Agents That Act as gp120-CD4 Inhibitors
Authors: Tiberi Marika , Tintori Cristina , Ceresola Elisa Rita , Fazi Roberta , Zamperini Claudio , Calandro Pierpaolo , Franchi Luigi , Selvaraj Manikandan , Botta Lorenzo , Sampaolo Michela , Saita Diego , Ferrarese Roberto , Clementi Massimo , Canducci Filippo , Botta Maurizio
Published: March 2014

We report here the synthesis of 2-aminothiazolones along with their biological properties as novel anti-HIV agents. Such compounds have proven to act through the inhibition of the gp120-CD4 protein-protein interaction that occurs at the very early stage of the HIV-1 entry process. No cytotoxicity was found for these compounds, and broad antiviral activities against laboratory strains and pseudotyped viruses were documented. Docking simulations have also been applied to predict the mechanism, at the molecular level, by which the inhibitors were able to interact within the Phe43 cavity of HIV-1 gp120. Furthermore, a preliminary absorption, distribution, metabolism, and excretion (ADME) evaluation was performed. Overall, this study led the basis for the development of more potent HIV entry inhibitors.
Differential Requirement for PBP1a and PBP1b in
In Vivo
and
In Vitro
Fitness of Vibrio cholerae
Authors: Dörr Tobias , Möll Andrea , Chao Michael C. , Cava Felipe , Lam Hubert , Davis Brigid M. , Waldor Matthew K.
Published: March 2014

We investigated the roles of the
Vibrio cholerae
high-molecular-weight bifunctional penicillin binding proteins, PBP1a and PBP1b, in the fitness of this enteric pathogen. Using a screen for synthetic lethality, we found that the
V. cholerae
PBP1a and PBP1b proteins, like their
Escherichia coli
homologues, are each essential in the absence of the other and in the absence of the other's putative activator, the outer membrane lipoproteins LpoA and LpoB, respectively. Comparative analyses of
V. cholerae
mutants suggest that PBP1a/LpoA of
V. cholerae
play a more prominent role in generating and/or maintaining the pathogen's cell wall than PBP1b/LpoB.
V. cholerae
lacking PBP1b or LpoB exhibited wild-type growth under all conditions tested. In contrast,
V. cholerae
lacking PBP1a or LpoA exhibited growth deficiencies in minimal medium, in the presence of deoxycholate and bile, and in competition assays with wild-type cells both
in vitro
and in the infant mouse small intestine. PBP1a pathway mutants are particularly impaired in stationary phase, which renders them sensitive to a product(s) present in supernatants from stationary-phase wild-type cells. The marked competitive defect of the PBP1a pathway mutants
in vivo
was largely absent when exponential-phase cells rather than stationary-phase cells were used to inoculate suckling mice. Thus, at least for
V. cholerae
PBP1a pathway mutants, the growth phase of the inoculum is a key modulator of infectivity.
Vibrio vulnificus Biotype 3 Multifunctional Autoprocessing RTX Toxin Is an Adenylate Cyclase Toxin Essential for Virulence in Mice
Authors: Ziolo Kevin J. , Jeong Hee-Gon , Kwak Jayme S. , Yang Shuangni , Lavker Robert M. , Satchell Karla J. F.
Published: March 2014

Vibrio vulnificus
is an environmental organism that causes both food-borne and wound infections with high morbidity and mortality in humans. The annual incidence and global distribution of infections associated with this pathogen are increasing with climate change. In the late 1990s, an outbreak of tilapia-associated wound infections in Israel was linked to a previously unrecognized variant of
V. vulnificus
designated biotype 3. The sudden emergence and clonality of the outbreak suggest that this strain may be a true newly emergent pathogen with novel virulence properties compared to those of other
V. vulnificus
strains. In a subcutaneous infection model to mimic wound infection, the multifunctional autoprocessing RTX (MARTX) toxin of biotype 3 strains was shown to be an essential virulence factor contributing to highly inflammatory skin wounds with severe damage affecting every tissue layer. We conducted a sequencing-based analysis of the MARTX toxin and found that biotype 3 MARTX toxin has an effector domain structure distinct from that of either biotype 1 or biotype 2. Of the two new domains identified, a domain similar to
Pseudomonas aeruginosa
ExoY was shown to confer adenylate cyclase activity on the MARTX toxin. This is the first demonstration that the biotype 3 MARTX toxin is essential for virulence and that the ExoY-like MARTX effector domain is a catalytically active adenylate cyclase.
Toll-Like Receptor 2-Dependent Protection against Pneumococcal Carriage by Immunization with Lipidated Pneumococcal Proteins
Authors: Moffitt Kristin , Skoberne Mojca , Howard Angela , Gavrilescu L. Cristina , Gierahn Todd , Munzer Scott , Dixit Bharat , Giannasca Paul , Flechtner Jessica Baker , Malley Richard
Published: March 2014

Infections withStreptococcus pneumoniaecause substantial morbidity and mortality, particularly in children in developing nations. Polysaccharide-conjugate vaccines provide protection against both invasive disease and colonization, but their use in developing countries is limited by restricted serotype coverage and expense of manufacture. Using proteomic screens, we recently identified several antigens that protected mice from pneumococcal colonization in a CD4+T cell- and interleukin-17A (IL-17A)-dependent manner. Since several of these proteins are lipidated, we hypothesized that their immunogenicity and impact on colonization are in part due to activation of Toll-like receptor 2 (TLR2), a receptor for lipoproteins. Here we show that lipidated versions of the antigens elicited significantly higher activation of both human embryonic kidney cells engineered to express TLR2 (HEK-TLR2) and wild-type (WT) murine macrophages than nonlipidated mutant antigens. Lipoprotein-stimulated secretion of proinflammatory cytokines was ∼10× to ∼100× lower in murine TLR2-deficient macrophages than in WT macrophages. Subcutaneous immunization of C57BL/6 mice with protein subunit vaccines containing one or two of these lipoproteins or protein fusion constructs bearing N-terminal lipid adducts elicited a robust IL-17A response and a significant reduction in colonization compared with immunization with alum alone. In contrast, immunization ofTlr2−/−mice elicited no detectable IL-17A response and no protection against pneumococcal colonization. These experiments suggest that the lipid moieties enhance the immunogenicity and protective efficacy of pneumococcal TH17 antigens through activation of TLR2. Thus, triggering TLR2 with an antigen-specific protein subunit formulation is a possible strategy for the development of a serotype-independent pneumococcal vaccine that would reduce pneumococcal carriage.
The clinical dilemma of treating transient ischaemic attack-like symptoms in patients with coexisting arteriovenous malformation
Authors: Jabbari Edwin , Sethuraman Sakthivel , Sekaran Lakshmanan
Published: March 2014

Antiplatelet agents are established, evidence-based treatments to reduce the risk of subsequent stroke in patients diagnosed with transient ischaemic attack (TIA). This case discusses the clinical dilemma clinicians are faced with when treating TIA-like symptoms in patients with coexisting arteriovenous malformation (AVM). A 65-year-old Caucasian woman reported a sudden onset of right hand weakness and impaired coordination. The episode lasted for 1 min and then resolved completely. She was subsequently diagnosed with a TIA and started on aspirin 75 mg. Her coexisting medical history included a large left-sided parietal-occipital AVM. The case highlights the clinician's need to balance the risk posed by antiplatelet agents increasing the likelihood of AVM rupture between the risk of untreated TIA progressing to stroke. Factors worth considering include number of vascular risk factors, AVM-related steal phenomena, size of AVM and whether or not there has been previous AVM-related haemorrhage.
Sestamibi scintigraphy for parathyroid localisation: a reminder of the dangers of false positives
Authors: Whitcroft Katherine Lisa , Sharma Anup
Published: March 2014

Surgical parathyroidectomy is the only curative treatment for primary hyperparathyroidism. As minimally invasive parathyroidectomy increases in popularity, so does reliance on preoperative parathyroid localisation techniques. One such technique is sestamibi scintigraphy. We report a case of false-positive sestamibi scintigraphy caused by follicular variant of papillary thyroid carcinoma. Subsequent completion thyroidectomy was not possible due to widespread postoperative fibrosis. This case, therefore, highlights the potential dangers of false-positive results due to thyroid carcinoma and encourages surgeons to consider this possibility when faced with intrathyroidal or otherwise ambiguous parathyroid localisation results.
Injury and illness definitions and data collection procedures for use in epidemiological studies in Athletics (track and field): Consensus statement
Authors: Timpka Toomas , Alonso Juan-Manuel , Jacobsson Jenny , Junge Astrid , Branco Pedro , Clarsen Ben , Kowalski Jan , Mountjoy Margo , Nilsson Sverker , Pluim Babette , Renström Per , Rønsen Ola , Steffen Kathrin , Edouard Pascal
Published: March 2014

Background

Movement towards sport safety in Athletics through the introduction of preventive strategies requires consensus on definitions and methods for reporting epidemiological data in the various populations of athletes.

Objective

To define health-related incidents (injuries and illnesses) that should be recorded in epidemiological studies in Athletics, and the criteria for recording their nature, cause and severity, as well as standards for data collection and analysis procedures.

Methods

A 1-day meeting of 14 experts from eight countries representing a range of Athletics stakeholders and sport science researchers was facilitated. Definitions of injuries and illnesses, study design and data collection for epidemiological studies in Athletics were discussed during the meeting. Two members of the group produced a draft statement after this meeting, and distributed to the group members for their input. A revision was prepared, and the procedure was repeated to finalise the consensus statement.

Results

Definitions of injuries and illnesses and categories for recording of their nature, cause and severity were provided. Essential baseline information was listed. Guidelines on the recording of exposure data during competition and training and the calculation of prevalence and incidences were given. Finally, methodological guidance for consistent recording and reporting on injury and illness in athletics was described.

Conclusions

This consensus statement provides definitions and methodological guidance for epidemiological studies in Athletics. Consistent use of the definitions and methodological guidance would lead to more reliable and comparable evidence.
THE INFLUENCE OF MUSCLE TIGHTNESS OF LOWER EXTREMITIES ON LOW BACK PAIN IN YOUNG FEMALE FIGURE SKATERS
Authors: Abe A , Sato K , Mitsueda S , Kimura M , Hirooka E , Tsuchiya A , Kanisawa I
Published: March 2014

Background

It has been reported that low back pain (LBP) is a major problem in figure skaters. However, the relationship between flexibility or muscle strength and LBP among figure skaters is unclear.

Objective

To investigate the influence of flexibility and muscle strength on the incidence of LBP in young figure skaters.

Design

Retrospective cohort study.

Setting

A study of an amateur figure skating team in Japan.

Participants

39 female figure skaters aged 9–16 years were included in this study. They were divided into an LBP group (14 members, 11.9±1.9 years) and a control group (25 members, 11.8±1.9 years) from our injury records of the previous 25 months.

Main outcome measurements

Five physical examinations (Thomas test, Ober test, finger-floor distance, trunk rotation test, and abdominal muscle test) were performed on all subjects. The trunk rotation test was performed with the subjects in the prone position with shoulder abduction at 90°. Subjects attempted to rotate their toe toward their opposite middle finger. The abdominal muscle strength was scored 1–10. The positive rates of Thomas test and Ober test, finger-floor distance (cm), toe-finger distance (cm), abdominal muscle test score were compared in the 2 groups. The Chi-square test and Mann-Whitney U test were used for statistical analysis (P<.05).

Results

The positive rate of Ober test was significantly higher in the LBP group (78.6%) than in the control group (36.0%). There were no significant differences in other tests.

Conclusions

Our research showed that figure skaters who experienced LBP had tightness of anterior and lateral hip muscles such as the Tensor fasciae latae muscle. These results suggest that reduction of hip muscle tightness might be effective in preventing LBP in young figure skaters.
EVALUATING INFLUENCES ON CLASSIFICATIONS OF SEVERITY FOR INJURIES IN PROFESSIONAL FOOTBALL
Authors: Hammond L , Lilley J , Pope G , Ribbans W
Published: March 2014

Background

According to consensus definitions for football surveillance, injury severity is classified from ‘slight’ to ‘career ending’, based on number of days absence from participation.

Objective

To examine whether different definitions of return to participation (RTP), and playing in matches while injured, affect groupings of injury severity in professional football.

Design

Secondary analysis of prospective injury data.

Setting

English league football.

Participants

Male professional footballers contracted to a Championship, League 1 and League 2 football team (n=78).

Interventions

1) RTP, defined as ‘return to full participation in training (RTT)’ and ‘return to match play (RTM)’ in 161 injuries. 2) Presence of pain or symptoms that directly preceded or followed time loss, in 45 episodes of playing while injured.

Main outcome measurements

Injury severity, measured by the number of days from date of injury to RTP, expressed according to consensus statement severity groupings.

Results

Median days absence from participation was significantly higher for RTM than RTT, although this did not affect average severity groupings (z=-8.824, P<.001; RTM: mean 15.7±2.3 days [moderate injury], median 6 days [mild injury]; RTT: mean 10.9±2.2 days [moderate injury], median 4 days [mild injury]). Differences were observed in the distribution of injuries grouped according to their severity with the two definitions of RTP. Two thirds of cases where athletes played in matches while injured were reclassified into higher severity groupings when the time spent playing in matches while injured, either directly preceding or following a period of absence, was counted.

Conclusions

When measured in days, football injury severity is directly influenced by definitions of RTP, and may be affected by match scheduling. Pain or injury symptoms do not contribute towards current severity classifications, yet often precede or follow a period of absence. Therefore, expressions of injury severity in football should encompass more than just absence from participation.
POTENTIAL RISK FACTORS FOR HAMSTRING MUSCLE STRAIN INJURY DURING THE LATE SWING PHASE OF SPRINTING
Authors: Higashihara A , Nagano Y , Ono T , Fukubayashi T
Published: March 2014

Background

The hamstring muscles are susceptible to strain injury during sprinting, and the biceps femoris long head (BFlh) is reportedly the most frequently injured muscle. Therefore, elucidation of the risk factors is of particular concern for injury prevention.

Objective

To clarify the potential risk factors for the incidence of muscle strain injury in each hamstring muscle by comparing the time of occurrence of peak musculotendon length and electromyography (EMG) activation during the late swing phase of sprinting.

Design

Descriptive laboratory study.

Setting

Male college track and field athletes.

Participants

13 male sprinters (age 20.2±0.6 years).

Intervention

Full-body kinematics and EMG of the BFlh and semitendinosus (ST) were recorded during overground sprinting at maximum effort. The hamstring musculotendon lengths were computed by using a three-dimensional musculoskeletal model.

Main outcome measurements

The time at the peak musculotendon length, in terms of percentage of the running gait cycle, was calculated and compared with that of the peak EMG activity.

Results

The peak length of the BFlh and ST was observed during the late swing phase, at 86.7% [2.5%] and 81.1% [2.5%] gait cycle, respectively (mean [SD]). A significant difference was observed in the time of the peak musculotendon length (P<.001). Peak EMG activation time of the BFlh occurred significantly later (86.0% [7.9%] gait cycle, P<.01) than that of the ST (76.2% [7.8%] gait cycle). The peak musculotendon length was synchronous with the peak EMG activation in the BFlh, while a statistically significant difference was observed between these values in the ST (P<.05).

Conclusions

The results indicate that the BFlh is exposed to instantaneous high tensile force during the late swing phase of sprinting, suggesting a higher potential risk for strain injury among the hamstring muscles.
PRESSURES EXERTED BY COMMERCIALLY AVAILABLE LOWER LIMB COMPRESSION GARMENTS
Authors: Hill J , Howatson G , van Someren K , Davidson S , Pedlar C
Published: March 2014

Background

Commercially available compression garments (CGs) enhance recovery from exercise in some, but not all studies. It has been suggested that the minimum physiologically effective pressure is 17.3 mmHg at the lower leg decreasing to 15.1 mmHg at the thigh (Watanuki and Murata, 1994). CGs are usually fitted using a generalised sizing system based on height and mass, potentially causing variability in the pressure exerted by the garment.

Objective

We aimed to quantify the pressure, and the variability in pressure, exerted on the leg by CGs fitted according to the manufacturers instructions.

Participants

50 healthy, physically active individuals (n=26 male, n=24 female; age 18–65years) volunteered to participate.

Design

Participants were fitted with CGs according to manufacturers guidelines. The compressive force of the garments was measured in participants standing in the anatomical position including: the medial aspect of the calf at the site of maximal girth and at the midpoint of the femur measured between the inguinal crease and the superior aspect of the patella, of the lower limb. Data were compared to target pressure values.

Results

Pressure fell short of target values by 3% and 20% at the calf and by 34% and 47% at the thigh for males and females respectively.

Figure 1

Box plots representing the mean, standard deviation, upper and lower quartiles for pressure exerted at the calf and thigh for males and females and compared to the target pressure suggested by Watanuki and Murata (1994).

Conclusion

Many individuals may not be experiencing an adequate pressure from CG (Figure 1); this might explain the inconsistency within the literature regarding CG and recovery. Future research should measure and control for actual pressure exerted by the garment.
TWO DIMENSIONAL ANALYSIS OF LANDING KINEMATICS IN MALE AND FEMALE EARLY ADOLESCENT SECONDARY SCHOOL ATHLETES
Authors: Holden S , Colin B , Wang D , Doherty C , Delahunt E
Published: March 2014

Background

The intensity and magnitude of secondary school sports participation is increasing annually. In this population there is a high incidence of anterior cruciate ligament injury, particularly in females. Two dimensional (2D) lower limb biomechanical analysis may present an inexpensive and clinically applicable way to evaluate biomechanical risk factors for knee injury in this population.

Objective

To compare 2D landing biomechanics of early adolescent male and female athletes in their first year of secondary school.

Design

Cross-sectional.

Setting

Secondary school gymnasium.

Participants

42 male (age=13.06±2.5 years) and 50 female (age=13.09±2.3 years) early adolescent secondary school athletes. All participants were fully engaged in sports and free from injury at the time of testing.

Interventions

Each participant performed 3 drop vertical jump (DVJ) trials. Frontal and sagittal plane knee angles were recorded by video cameras for the dominant and non-dominant limbs.

Main Outcome Measurements

The categorical independent variables were gender (malevsfemale) and limb (dominantvsnon-dominant). Knee flexion angle and frontal plane knee angle (FPKA) measured at the video frame prior to initial contact (pre-IC) were used as dependant variables. Peak knee flexion and peak FPKA following IC were also used as dependant variables.

Results

There was a significant main effect for gender. Females demonstrated greater FPKA pre-IC (P<.01; mean difference=2.32°±0.45°) and peak FPKA following IC (P<.01; mean difference=9.82°±1.26°). Females displayed significantly less knee flexion pre-IC (P<.01; mean difference=3.22°±0.95°), but no differences were observed for peak knee flexion following IC (P>.05).

Conclusions

The results of the current investigation show that early adolescent female athletes demonstrate less desirable jump landing biomechanical profiles than their male counterparts, which may have implications for knee injury. 2D analysis could be utilised in this population to identify those at an increased risk of injury.
OVERUSE AND TRAUMATIC MUSCULOSKELETAL EXTREMITY INJURIES IN SCHOOL CHILDREN
Authors: Jespersen E , Holst R , Franz C , Rexen C , Klakk H , Wedderkopp N
Published: March 2014

Background

Injuries sustained in sports and leisure time has been established as a leading cause of the paediatric injury burden in western countries. Injuries reported are mostly traumatic, but there is a growing concern about overuse injuries in children.

Objective

The objectives of this prospective cohort study were to report the incidence, prevalence and duration of traumatic and overuse injuries during a period of 2.5 years and to estimate the injury incidence rates.

Design

Prospective cohort study.

Setting

10 public schools in the municipality of Svendborg, Denmark.

Participants

A total of 1 259 school children aged 6–12 years participating in the Childhood Health, Activity, and Motor Performance School Study Denmark.

Risk factor assessment

School children were surveyed each week during a period of 2.5 years. Injuries were reported by parents answering mobile phone text questions on a weekly basis (response rate 96.2%) and prospectively diagnosed by clinicians. Physical activity was measured from text messaging and accelerometer assessments.

Main outcome measurements

Overuse and traumatic musculoskeletal extremity injuries.

Results

A total number of 1229 injuries were diagnosed with a weekly mean injury incidence and prevalence being 1.2% and 4.6% respectively. Twice as many overuse as traumatic extremity injuries were diagnosed with mean injury durations being 5.3 and 4.4 weeks respectively. Overuse injury incidence rate was 1.03 injuries per 1000 physical activity units (95% CI 0.95–1.10). Traumatic incidence rate was 0.56 injuries per 1000 physical activity units (95% CI 0.51–0.61).

Conclusions

This study has added a wider perspective to the area concerning musculoskeletal extremity injuries in school children by including overuse injuries. The understanding of injury epidemiology in children is fundamental to acknowledge and ensure the appropriate prevention and treatment in relation to the growing and physically active child.