bluuebunny/crossref_metadata_2025 huggingface dataset:
Reconstitution of Membrane Proteins into Model Membranes: Seeking Better Ways to Retain Protein Activities
Authors: Shen Hsin-Hui , Lithgow Trevor , Martin Lisa
Published: January 2013

The function of any given biological membrane is determined largely by the specific set of integral membrane proteins embedded in it, and the peripheral membrane proteins attached to the membrane surface. The activity of these proteins, in turn, can be modulated by the phospholipid composition of the membrane. The reconstitution of membrane proteins into a model membrane allows investigation of individual features and activities of a given cell membrane component. However, the activity of membrane proteins is often difficult to sustain following reconstitution, since the composition of the model phospholipid bilayer differs from that of the native cell membrane. This review will discuss the reconstitution of membrane protein activities in four different types of model membrane — monolayers, supported lipid bilayers, liposomes and nanodiscs, comparing their advantages in membrane protein reconstitution. Variation in the surrounding model environments for these four different types of membrane layer can affect the three-dimensional structure of reconstituted proteins and may possibly lead to loss of the proteins activity. We also discuss examples where the same membrane proteins have been successfully reconstituted into two or more model membrane systems with comparison of the observed activity in each system. Understanding of the behavioral changes for proteins in model membrane systems after membrane reconstitution is often a prerequisite to protein research. It is essential to find better solutions for retaining membrane protein activities for measurement and characterization in vitro.
Crystal Structure of Dimeric Flavodoxin from Desulfovibrio gigas Suggests a Potential Binding Region for the Electron-Transferring Partner
Authors: Hsieh Yin-Cheng , Chia Tze , Fun Hoong-Kun , Chen Chun-Jung
Published: January 2013

Flavodoxins, which exist widely in microorganisms, have been found in various pathways with multiple physiological functions. The flavodoxin (Fld) containing the cofactor flavin mononucleotide (FMN) from sulfur-reducing bacteria Desulfovibrio gigas (D. gigas) is a short-chain enzyme that comprises 146 residues with a molecular mass of 15 kDa and plays important roles in the electron-transfer chain. To investigate its structure, we purified this Fld directly from anaerobically grown D. gigas cells. The crystal structure of Fld, determined at resolution 1.3 Å, is a dimer with two FMN packing in an orientation head to head at a distance of 17 Å, which generates a long and connected negatively charged region. Two loops, Thr59–Asp63 and Asp95–Tyr100, are located in the negatively charged region and between two FMN, and are structurally dynamic. An analysis of each monomer shows that the structure of Fld is in a semiquinone state; the positions of FMN and the surrounding residues in the active site deviate. The crystal structure of Fld from D. gigas agrees with a dimeric form in the solution state. The dimerization area, dynamic characteristics and structure variations between monomers enable us to identify a possible binding area for its functional partners.
Gamma-Aminobutyric Acid Production Using Immobilized Glutamate Decarboxylase Followed by Downstream Processing with Cation Exchange Chromatography
Authors: Lee Seungwoon , Ahn Jungoh , Kim Yeon-Gu , Jung Joon-Ki , Lee Hongweon , Lee Eun
Published: January 2013

We have developed a gamma-aminobutyric acid (GABA) production technique using his-tag mediated immobilization of Escherichia coli-derived glutamate decarboxylase (GAD), an enzyme that catalyzes the conversion of glutamate to GABA. The GAD was obtained at 1.43 g/L from GAD-overexpressed E. coli fermentation and consisted of 59.7% monomer, 29.2% dimer and 2.3% tetramer with a 97.6% soluble form of the total GAD. The harvested GAD was immobilized to metal affinity gel with an immobilization yield of 92%. Based on an investigation of specific enzyme activity and reaction characteristics, glutamic acid (GA) was chosen over monosodium glutamate (MSG) as a substrate for immobilized GAD, resulting in conversion of 2.17 M GABA in a 1 L reactor within 100 min. The immobilized enzymes retained 58.1% of their initial activities after ten consecutive uses. By using cation exchange chromatography followed by enzymatic conversion, GABA was separated from the residual substrate and leached GAD. As a consequence, the glutamic acid was mostly removed with no detectable GAD, while 91.2% of GABA was yielded in the purification step.
Epistemological Levelism and Dynamical Complex Systems: The Case of Crowd Behaviour
Authors: Bandini Stefania , Vizzari Giuseppe
Published: January 2013

The main aim of this paper is to show how the design and creation of computational models to study and simulate of the behaviour of dynamical complex systems, and in particular crowds of pedestrian, actually implicitly employs elements of a framework introduced by Luciano Floridi in his paper “The Method of Levels of Abstraction”. The example of the computer based simulation of the complex phenomenon of crowd dynamics and the related knowledge requiring different abstract levels and representation will be introduced in order to show how concepts like observables and system behaviour are commonly employed to compare and evaluate simulation models.
Non-Metallic Biomaterials for Tooth Repair and Replacement. By Pekka Vallittu, Woodhead Publishing, 2013; 406 pages. Price £145.00/US$245.00/€175.00 ISBN 978-0-85709-244-1
Authors: Lin Shu-Kun
Published: January 2013

1. Discusses the properties of enamel and dentin and their role in adhesive dental restoration;2. Chapters also examine the wear properties of dental ceramics, glasses and bioactive glass ceramics for tooth repair and replacement;3. Dental composites and antibacterial restorative materials are also considered;4. Provides a concise overview of non-metallic biomaterials for dental clinicians, materials scientists and academic researchers alike.As the demand for healthy, attractive teeth increases, the methods and materials employed in restorative dentistry have become progressively more advanced. Non-metallic biomaterials for tooth repair and replacement focuses on the use of biomaterials for a range of applications in tooth repair and, in particular, dental restoration.
Hardness and Elastic Modulus on Six-Fold Symmetry Gold Nanoparticles
Authors: Ramos Manuel , Ortiz-Jordan Luis , Hurtado-Macias Abel , Flores Sergio , Elizalde-Galindo José , Rocha Carmen , Torres Brenda , Zarei-Chaleshtori Maryam , Chianelli Russell
Published: January 2013

The chemical synthesis of gold nanoparticles (NP) by using gold (III) chloride trihydrate (HAuCl∙3H2O) and sodium citrate as a reducing agent in aqueous conditions at 100 °C is presented here. Gold nanoparticles areformed by a galvanic replacement mechanism as described by Lee and Messiel. Morphology of gold-NP was analyzed by way of high-resolution transmission electron microscopy; results indicate a six-fold icosahedral symmetry with an average size distribution of 22 nm. In order to understand the mechanical behaviors, like hardness and elastic moduli, gold-NP were subjected to nanoindentation measurements—obtaining a hardness value of 1.72 GPa and elastic modulus of 100 GPa in a 3–5 nm of displacement at the nanoparticle’s surface.
Comparative Study of Loading of Anodic Porous Alumina with Silver Nanoparticles Using Different Methods
Authors: Thorat Sanjay , Diaspro Alberto , Scarpellini Alice , Povia Mauro , Salerno Marco
Published: January 2013

Three different routes were used to infiltrate the pores of anodic porous alumina templates with silver nanoparticles, selected as an example of a bioactive agent. The three methods present a continuous grading from more physical to more chemical character, starting from ex situ filling of the pores with pre-existing particles, moving on to in situ formation of particles in the pores by bare calcination and ending with in situ calcination following specific chemical reactions. The resulting presence of silver inside the pores was assessed by means of energy dispersive X-ray spectroscopy and X-ray diffraction. The number and the size of nanoparticles were evaluated by scanning electron microscopy of functionalized alumina cross-sections, followed by image analysis. It appears that the best functionalization results are obtained with the in situ chemical procedure, based on the prior formation of silver ion complex by means of ammonia, followed by reduction with an excess amount of acetaldehyde. Elution of the silver content from the chemically functionalized alumina into phosphate buffer saline has also been examined, demonstrating a sustained release of silver over time, up to 15 h.
Modeling the Microstructure Curvature of Boron-Doped Silicon in Bulk Micromachined Accelerometer
Authors: Zhou Wu , Yu Huijun , Peng Bei , Shen Huaqin , He Xiaoping , Su Wei
Published: January 2013

Microstructure curvature, or buckling, is observed in the micromachining of silicon sensors because of the doping of impurities for realizing certain electrical and mechanical processes. This behavior can be a key source of error in inertial sensors. Therefore, identifying the factors that influence the buckling value is important in designing MEMS devices. In this study, the curvature in the proof mass of an accelerometer is modeled as a multilayered solid model. Modeling is performed according to the characteristics of the solid diffusion mechanism in the bulk-dissolved wafer process (BDWP) based on the self-stopped etch technique. Moreover, the proposed multilayered solid model is established as an equivalent composite structure formed by a group of thin layers that are glued together. Each layer has a different Young’s modulus value and each undergoes different volume shrinkage strain owing to boron doping in silicon. Observations of five groups of proof mass blocks of accelerometers suggest that the theoretical model is effective in determining the buckling value of a fabricated structure.
Beneficial Effects of Marine Algal Compounds in Cosmeceuticals
Authors: Thomas Noel , Kim Se-Kwon
Published: January 2013

The name “cosmeceuticals” is derived from “cosmetics and pharmaceuticals”, indicating that a specific product contains active ingredients. Marine algae have gained much importance in cosmeceutical product development due to their rich bioactive compounds. In the present review, marine algal compounds (phlorotannins, sulfated polysaccharides and tyrosinase inhibitors) have been discussed toward cosmeceutical application. In addition, atopic dermatitis and the possible role of matrix metalloproteinase (MMP) in skin-related diseases have been explored extensively for cosmeceutical products. The proper development of marine algae compounds will be helpful in cosmeceutical product development and in the development of the cosmeceutical industry.
Comparative ANNs with Different Input Layers and GA-PLS Study for Simultaneous Spectrofluorimetric Determination of Melatonin and Pyridoxine HCl in the Presence of Melatonin’s Main Impurity
Authors: Darwish Hany , Attia Mohamed , Abdelhameed Ali , Alanazi Amer , Bakheit Ahmed
Published: January 2013

Melatonin (MLT) has many health implications, therefore it is important to develop specific analytical methods for the determination of MLT in the presence of its main impurity, N-{2-[1-({3-[2-(acetylamino)ethyl]-5-methoxy-1H-indol-2-yl}methyl)-5-methoxy-1H-indol-3-yl]ethyl}acetaamide (DMLT) and pyridoxine HCl (PNH) as a co-formulated drug. This work describes simple, sensitive, and reliable four multivariate calibration methods, namely artificial neural network preceded by genetic algorithm (GA-ANN), principal component analysis (PCA-ANN) and wavelet transform procedures (WT-ANN) as well as partial least squares preceded by genetic algorithm (GA-PLS) for the spectrofluorimetric determination of MLT and PNH in the presence of DMLT. Analytical performance of the proposed methods was statistically validated with respect to linearity, accuracy, precision and specificity. The proposed methods were successfully applied for the assay of MLT in laboratory prepared mixtures containing up to 15% of DMLT and in commercial MLT tablets with recoveries of no less than 99.00%. No interference was observed from common pharmaceutical additives and the results compared favorably with those obtained by a reference method.
Comparative Analysis of Thermal Behavior, Isothermal Crystallization Kinetics and Polymorphism of Palm Oil Fractions
Authors: Zhang Xia , Li Lin , Xie He , Liang Zhili , Su Jianyu , Liu Guoqin , Li Bing
Published: January 2013

Thermal behavior of palm stearin (PS) and palm olein (PO) was explored by monitoring peak temperature transitions by differential scanning calorimetry (DSC). The fatty acid composition (FAC), isothermal crystallization kinetics studied by pulsed Nuclear Magnetic Resonance (pNMR) and isothermal microstructure were also compared. The results indicated that the fatty acid composition had an important influence on the crystallization process. PS and PO both exhibited more multiple endotherms than exotherms which showed irregular peak shapes. An increasing in cooling rate, generally, was associated with an increase in peak size. Application of the Avaimi equation to isothermal crystallization of PS and PO revealed different nucleation and growth mechanisms based on the Avrami exponents. PS quickly reached the end of crystallization because of more saturated triacylglycerol (TAG). The Avrami index of PS were the same as PO under the same isothermal condition at lower temperatrue, indicating that the crystallization mechanism of the two samples based on super-cooling state were the same. According to the polarized light microscope (PLM) images, crystal morphology of PS and PO was different. With the temperature increased, the structure of crystal network of both PS and PO gradually loosened.
A Novel in Situ FPAR Measurement Method for Low Canopy Vegetation Based on a Digital Camera and Reference Panel
Authors: Liu Liangyun , Peng Dailiang , Hu Yong , Jiao Quanjun
Published: January 2013

The fraction of absorbed photosynthetically active radiation (FPAR) is a key parameter in describing the exchange of fluxes of energy, mass and momentum between the surface and atmosphere. In this study, we present a method to measure FPAR using a digital camera and a reference panel. A digital camera was used to capture color images of low canopy vegetation, which contained a reference panel in one corner of the field of view (FOV). The digital image was classified into photosynthetically active vegetation, ground litter, sunlit soil, shadow soil, and the reference panel. The relative intensity of the incident photosynthetically active radiation (PAR), scene-reflected PAR, exposed background absorbed PAR and the green vegetation-covered ground absorbed PAR were derived from the digital camera image, and then FPAR was calculated. This method was validated on eight plots with four vegetation species using FPAR measured by a SunScan instrument. A linear correlation with a coefficient of determination (R2) of 0.942 and mean absolute error (MAE) of 0.031 was observed between FPAR values derived from the digital camera and measurement using the SunScan instrument. The result suggests that the present method can be used to accurately measure the FPAR of low canopy vegetation.
Applications of Flexible Ultrasonic Transducer Array for Defect Detection at 150 °C
Authors: Shih Jeanne-Louise , Wu Kuo-Ting , Jen Cheng-Kuei , Chiu Chun-Hsiung , Tzeng Jing-Chi , Liaw Jiunn-Woei
Published: January 2013

In this study, the feasibility of using a one dimensional 16-element flexible ultrasonic transducer (FUT) array for nondestructive testing at 150 °C is demonstrated. The FUT arrays were made by a sol-gel sprayed piezoelectric film technology; a PZT composite film was sprayed on a titanium foil of 75 µm thickness. Since the FUT array is flexible, it was attached to a steel pipe with an outer diameter of 89 mm and a wall thickness of 6.5 mm at 150 °C. Using the ultrasonic pulse-echo mode, pipe thickness measurements could be performed. Moreover, using the ultrasonic pulse-echo and pitch-catch modes of each element of FUT array, the defect detection was performed on an Al alloy block of 30 mm thickness with a side-drilled hole (SDH) of f3 mm at 150 °C. In addition, a post-processing algorithm based on the total focusing method was used to process the full matrix of these A-scan signals of each single transmitter and multi-receivers, and then the phase-array image was obtained to indicate this defect- SDH. Both results show the capability of FUT array being operated at 150 °C for the corrosion and defect detections.
Registration of 3D and Multispectral Data for the Study of Cultural Heritage Surfaces
Authors: Chane Camille , Schütze Rainer , Boochs Frank , Marzani Franck
Published: January 2013

We present a technique for the multi-sensor registration of featureless datasets based on the photogrammetric tracking of the acquisition systems in use. This method is developed for the in situ study of cultural heritage objects and is tested by digitizing a small canvas successively with a 3D digitization system and a multispectral camera while simultaneously tracking the acquisition systems with four cameras and using a cubic target frame with a side length of 500 mm. The achieved tracking accuracy is better than 0.03 mm spatially and 0.150 mrad angularly. This allows us to seamlessly register the 3D acquisitions and to project the multispectral acquisitions on the 3D model.
A Flexible Sensor Technology for the Distributed Measurement of Interaction Pressure
Authors: Donati Marco , Vitiello Nicola , De Rossi Stefano , Lenzi Tommaso , Crea Simona , Persichetti Alessandro , Giovacchini Francesco , Koopman Bram , Podobnik Janez , Munih Marko , Carrozza Maria
Published: January 2013

We present a sensor technology for the measure of the physical human-robot interaction pressure developed in the last years at Scuola Superiore Sant’Anna. The system is composed of flexible matrices of opto-electronic sensors covered by a soft silicone cover. This sensory system is completely modular and scalable, allowing one to cover areas of any sizes and shapes, and to measure different pressure ranges. In this work we present the main application areas for this technology. A first generation of the system was used to monitor human-robot interaction in upper- (NEUROExos; Scuola Superiore Sant’Anna) and lower-limb (LOPES; University of Twente) exoskeletons for rehabilitation. A second generation, with increased resolution and wireless connection, was used to develop a pressure-sensitive foot insole and an improved human-robot interaction measurement systems. The experimental characterization of the latter system along with its validation on three healthy subjects is presented here for the first time. A perspective on future uses and development of the technology is finally drafted.
Rethinking What Counts. Perspectives on Wellbeing and Genuine Progress Indicator Metrics from a Canadian Viewpoint
Authors: Wilson Jeffrey , Tyedmers Peter
Published: January 2013

A prevailing undercurrent of doubt regarding the merits of economic growth has motivated efforts to rethink how we measure the success of economic policy and societal wellbeing. This article comments on efforts to better account for impacts of economic activity emphasizing genuine progress indicator (GPI) and wellbeing metrics from a Canadian viewpoint. The authors caution that GPI and related metrics are measures of human and social welfare and not adequate to account for the ecological costs associated with economic growth. In addition, the article discusses the suitability of wellbeing models and metrics for local scale applications, recognizing growing interest in these techniques at the urban and local level. The article concludes with a reflection on the uptake of GPI and wellbeing measures highlighting the Canadian experience.
Bacillus anthracis Protective Antigen Kinetics in Inhalation Spore-Challenged Untreated or Levofloxacin/ Raxibacumab-Treated New Zealand White Rabbits
Authors: Corey Alfred , Migone Thi-Sau , Bolmer Sally , Fiscella Michele , Ward Chris , Chen Cecil , Meister Gabriel
Published: January 2013

Inhaled Bacillus anthracis spores germinate and the subsequent vegetative growth results in bacteremia and toxin production. Anthrax toxin is tripartite: the lethal factor and edema factor are enzymatic moieties, while the protective antigen (PA) binds to cell receptors and the enzymatic moieties. Antibiotics can control B. anthracis bacteremia, whereas raxibacumab binds PA and blocks lethal toxin effects. This study assessed plasma PA kinetics in rabbits following an inhaled B. anthracis spore challenge. Additionally, at 84 h post-challenge, 42% of challenged rabbits that had survived were treated with either levofloxacin/placebo or levofloxacin/raxibacumab. The profiles were modeled using a modified Gompertz/second exponential growth phase model in untreated rabbits, with added monoexponential PA elimination in treated rabbits. Shorter survival times were related to a higher plateau and a faster increase in PA levels. PA elimination half-lives were 10 and 19 h for the levofloxacin/placebo and levofloxacin/raxibacumab groups, respectively, with the difference attributable to persistent circulating PA-raxibacumab complex. PA kinetics were similar between untreated and treated rabbits, with one exception: treated rabbits had a plateau phase nearly twice as long as that for untreated rabbits. Treated rabbits that succumbed to disease had higher plateau PA levels and shorter plateau duration than surviving treated rabbits.
Maize Aflatoxin Accumulation Segregates with Early Maturing Selections from an S2 Breeding Cross Population
Authors: Henry W.
Published: January 2013

Maize breeders continue to seek new sources of aflatoxin resistance, but most lines identified as resistance sources are late maturing. The vast difference in flowering time makes it hard to cross these lines with proprietary commercial lines that mature much earlier and often subjects the reproductive phase of these resistant lines to the hottest and driest portion of the summer, making silking, pollination and grain fill challenging. Two hundred crosses from the GEM Project were screened for aflatoxin accumulation at Mississippi State in 2008, and a subset of these lines were screened again in 2009. The breeding cross UR13085:S99g99u was identified as a potential source of aflatoxin resistance, and maturity-based selections were made from an S2 breeding population from this same germplasm source: UR13085:S99g99u-B-B. The earliest maturing selections performed poorly for aflatoxin accumulation, but later maturing selections were identified with favorable levels of aflatoxin accumulation. These selections, while designated as “late” within this study, matured earlier than most aflatoxin resistant lines presently available to breeders. Two selections from this study, designated S5_L7 and S5_L8, are potential sources of aflatoxin resistance and will be advanced for line development and additional aflatoxin screening over more site years and environments.
Base Composition and Translational Selection are Insufficient to Explain Codon Usage Bias in Plant Viruses
Authors: Cardinale Daniel , DeRosa Kate , Duffy Siobain
Published: January 2013

Viral codon usage bias may be the product of a number of synergistic or antagonistic factors, including genomic nucleotide composition, translational selection, genomic architecture, and mutational or repair biases. Most studies of viral codon bias evaluate only the relative importance of genomic base composition and translational selection, ignoring other possible factors. We analyzed the codon preferences of ssRNA (luteoviruses and potyviruses) and ssDNA (geminiviruses) plant viruses that infect translationally distinct monocot and dicot hosts. We found that neither genomic base composition nor translational selection satisfactorily explains their codon usage biases. Furthermore, we observed a strong relationship between the codon preferences of viruses in the same family or genus, regardless of host or genomic nucleotide content. Our results suggest that analyzing codon bias as either due to base composition or translational selection is a false dichotomy that obscures the role of other factors. Constraints such as genomic architecture and secondary structure can and do influence codon usage in plant viruses, and likely in viruses of other hosts.
Insights into the Roles of Cyclophilin A During Influenza Virus Infection
Authors: Liu Xiaoling , Zhao Zhendong , Liu Wenjun
Published: January 2013

Cyclophilin A (CypA) is the main member of the immunophilin superfamily that has peptidyl-prolyl cis-trans isomerase activity. CypA participates in protein folding, cell signaling, inflammation and tumorigenesis. Further, CypA plays critical roles in the replication of several viruses. Upon influenza virus infection, CypA inhibits viral replication by interacting with the M1 protein. In addition, CypA is incorporated into the influenza virus virions. Finally, Cyclosporin A (CsA), the main inhibitor of CypA, inhibits influenza virus replication through CypA-dependent and -independent pathways. This review briefly summarizes recent advances in understanding the roles of CypA during influenza virus infection.
How pure are your vesicles?
Authors: Webber Jason , Clayton Aled
Published: January 2013

We propose a straightforward method to estimate the purity of vesicle preparations by comparing the ratio of nano‐vesicle counts to protein concentration, using tools such as the increasingly available NanoSight platform and a colorimetric protein assay such as the BCA‐assay. Such an approach is simple enough to apply to every vesicle preparation within a given laboratory, assisting researchers as a routine quality control step. Also, the approach may aid in comparing/standardising vesicle purity across diverse studies, and may be of particular importance in evaluating vesicular biomarkers. We herein propose some criteria to aid in the definition of pure vesicles.
Thioester derivatives of the natural product psammaplin A as potent histone deacetylase inhibitors
Authors: Baud Matthias G J , Leiser Thomas , Petrucci Vanessa , Gunaratnam Mekala , Neidle Stephen , Meyer-Almes Franz-Josef , Fuchter Matthew J
Published: January 2013

There has been significant interest in the bioactivity of the natural product psammaplin A, most recently as a potent and isoform selective HDAC inhibitor. Here we report our preliminary studies on thioester HDAC inhibitors derived from the active monomeric (thiol) form of psammaplin A, as a means to improve compound delivery into cells. We have discovered that such compounds exhibit both potent cytotoxicity and enzymatic inhibitory activity against recombinant HDAC1. The latter effect is surprising since previous SAR suggested that modification of the thiol functionality should detrimentally affect HDAC potency. We therefore also report our preliminary studies on the mechanism of action of this observed effect.
Community-associated methicillin-resistant Staphylococcus aureus in children treated in Uruguay
Authors: Pardo Lorena , Vola Magdalena , Macedo-Viñas Marina , Machado Virginia , Cuello Dianna , Mollerach Marta , Castro Marta , Pírez Catalina , Varela Gustavo , Algorta Gabriela
Published: January 2013

Introduction: Staphylococcus aureus produces a variety of diseases among children, ranging from skin and soft tissue infections to invasive life-threatening diseases. Since 1990, an increasing number of diseases produced by community-associated methicillin-resistant S. aureus (CA-MRSA) isolates have been reported. The aim of this study was to describe the importance and the microbiological characteristics of S. aureus isolates recovered from children treated at the Hospital Pediátrico del Centro Hospitalario “Pereira Rossell” (HP-CHPR); focusing on invasive diseases caused by CA-MRSA isolates, as well as some clinical aspects of the diseases they have produced. Methodology: One hundred and twenty-five S. aureus isolates recovered from the HP-CHPR between 2003 and 2006 from children with invasive (n=89) and superficial diseases (n=36) were included. Genotypic and phenotypic characteristics of S. aureus isolates and relevant clinical aspects of each child were studied. Results: CA-MRSA isolates accounted for 73% of all S. aureus recovered from invasive (mainly bone and joint) infections, pneumonia and bacteraemia. The most common CA-MRSA strain recovered from invasive (n=65) and superficial (n=36) diseases had the following features: pulsotype A (type USA1100), SCCmec cassette type IV, Panton-Valentine Leukocidin genes positive, susceptibility to trimethoprim-sulfamethoxazole without the inducible macrolide-lincosamide-streptogramin B (iMLSB) resistance phenotype. No association between genotypic characteristics of invasive CA-MRSA isolates and clinical outcomes was found. Conclusions: CA-MRSA isolates produced a wide spectrum of invasive diseases in a public paediatric hospital between 2003 and 2006. Microbiologic characterization suggests the spread of an adapted CA-MRSA clone lacking erm genes.
Severe acute respiratory disease in health-care workers during the influenza H1N1 pandemic in Argentina
Authors: Pryluka Daniel , Lopardo Gustavo , Daciuk Lucia , Stecher Daniel , Bonvehi Pablo
Published: January 2013

Introduction: During the 2009 influenza H1N1virus pandemic, health-care workers were exposed to elevated risk of infection. The aim of this study was to estimate the risk for severe acute respiratory disease (SARD) in this population during the pandemic period in Argentina. Methodology: we conducted a retrospective survey in which all members of the Argentine Society of Infectious Diseases were invited to answer an online survey providing information on health-care staff working at their hospital or health center, who were hospitalized for SARD, between May and August 2009. Results were compared to population-based SARD surveillance data obtained from the Ministry of Public Health. Results: Fifty hospitals completed the survey. Out of a total population of 58,902 health-care workers, 41 were reported to have been hospitalized for SARD (hospitalization rate 69.6/100000), 19 of whom tested positive for H1N1 using real time polymerase chain reaction. Hospitalization rate in the general population during the same time period was 20.3/100000 (p < 0.01), thus indicating increased SARD hospitalization risk in health-care workers (OR 3.1 95% CI: 2.3 - 4.1; p < 0.01). Conclusions: During the 2009 pandemic, health-care workers in Argentina suffered increased risk of hospitalization due to SARD compared to the general population. We recommend immunization of all personnel, as well as enforcing stricter infection control measures in hospitals to prevent future transmission of influenza H1N1virus.
Comparison of two molecular methods for diagnosis of Chlamydia trachomatis
Authors: Molicotti Paola , Usai Donatella , Cubeddu Marina , Sechi Leonardo A , Zanetti Stefania
Published: January 2013

This item has no abstract. Follow the links below to access the full text.
Mitochondrial Superoxide Generation Enhances P2X7R-Mediated Loss of Cell Surface CD62L on Naive Human CD4+ T Lymphocytes
Authors: Foster John G. , Carter Edward , Kilty Iain , MacKenzie Amanda B. , Ward Stephen G.
Published: January 2013

Migration of naive CD4+ T lymphocytes into lymphoid tissue is essential for their activation and subsequent roles in adaptive immunity. The adhesion molecule L-selectin (CD62L), critical for this process, is highly expressed on naive CD4+ T lymphocytes and is downregulated upon T lymphocyte activation. We demonstrate protein expression of P2X7R on naive CD4+ T lymphocytes and show functional channel activity in whole-cell patch clamp recordings. CD62L downregulation occurs rapidly in response to extracellular ATP, a process that is blocked by selective antagonists of P2X7R. This loss of surface CD62L expression was not associated with externalization of phosphatidylserine. While investigating the mechanisms for this process, we revealed that pharmacological modulation of mitochondrial complex I or III, but not inhibition of NADPH oxidase, enhanced P2X7R-dependent CD62L downregulation by increasing ATP potency. Enhanced superoxide generation in the mitochondria of rotenone- and antimycin A–treated cells was observed and may contribute to the enhanced sensitivity of P2X7R to ATP. P2X7R-dependent exposure of phosphatidylserine was also revealed by preincubation with mitochondrial uncouplers prior to ATP treatment. This may present a novel mechanism whereby P2X7R-dependent phosphatidylserine exposure occurs only when cells have enhanced mitochondrial reactive oxygen species generation. The clearance of apoptotic cells may therefore be enhanced by this mechanism which requires functional P2X7R expression.
Cloning, Expression, and Functional Characterization of TL1A-Ig
Authors: Khan Samia Q. , Tsai Matthew S. , Schreiber Taylor H. , Wolf Dietlinde , Deyev Vadim V. , Podack Eckhard R.
Published: January 2013

TNF superfamily member 15 (TL1A) is the ligand for TNFR superfamily (TNFRSF)25. We previously reported that TNFRSF25 stimulation with an agonist Ab, 4C12, expands pre-existing CD4+Foxp3+ regulatory T cells (Tregs) in vivo. To determine how the physiological ligand differs from the Ab, we generated a soluble mouse TL1A-Ig fusion protein that forms a dimer of TL1A trimers in solution with an apparent molecular mass of 516 kDa. In vitro, TL1A-Ig mediated rapid proliferation of Foxp3+ Tregs and a population of CD4+Foxp3− conventional T cells. TL1A-Ig also blocked de novo biogenesis of inducible Tregs and it attenuated the suppressive function of Tregs. TNFRSF25 stimulation by TL1A-Ig in vivo induced expansion of Tregs such that they increased to 30–35% of all CD4+ T cells in the peripheral blood within 5 d of treatment. Treg proliferation in vivo was dependent on TCR engagement with MHC class II. Elevated Treg levels can be maintained for at least 20 d with daily injections of TL1A-Ig. TL1A-Ig–expanded Tregs expressed high levels of activation/memory markers KLRG1 and CD103 and were highly suppressive ex vivo. TL1A-Ig–mediated Treg expansion in vivo was protective against allergic lung inflammation, a mouse model for asthma, by reversing the ratio of conventional T cells to Tregs in the lung and blocking eosinophil exudation into the bronchoalveolar fluid. Thus, TL1A-Ig fusion proteins are highly active and tightly controllable agents to stimulate Treg proliferation in vivo, and they are uniquely able to maintain high levels of expanded Tregs by repeated administration.
L Chain Allelic Inclusion Does Not Increase Autoreactivity in Lupus-Prone New Zealand Black/New Zealand White Mice
Authors: Makdasi Efi , Eilat Dan
Published: January 2013

L chain allelic inclusion has been proposed as a B cell tolerance mechanism in addition to clonal deletion, clonal anergy, and receptor editing. It is said to rescue autoreactive B cells from elimination by diluting out the self-reactive BCR through the expression of a second innocuous L chain. In autoimmune animals, such as lupus-prone mice, allelically included B cells could be activated and produce pathogenic autoantibodies. We have previously shown that anti-DNA hybridomas from diseased New Zealand Black/New Zealand White F1 mice exhibit nearly perfect allelic exclusion. In the current study, we have analyzed single B cells from these and from nonautoimmune mice. In addition, we have cloned and expressed the Ig variable regions of several L chain–included B cells in cell culture. We find that although the number of L chain-included B cells increases as a result of receptor editing, the majority of such cells do not retain an autoreactive HxL chain combination and, therefore, allelic inclusion in itself does not serve as a B cell tolerance mechanism in these autoimmune mice.
IL-23–Independent Induction of IL-17 from γδT Cells and Innate Lymphoid Cells Promotes Experimental Intraocular Neovascularization
Authors: Hasegawa Eiichi , Sonoda Koh-Hei , Shichita Takashi , Morita Rimpei , Sekiya Takashi , Kimura Akihiro , Oshima Yuji , Takeda Atsunobu , Yoshimura Takeru , Yoshida Shigeo , Ishibashi Tatsuro , Yoshimura Akihiko
Published: January 2013

Choroidal neovascularization (CNV) is a characteristic of age-related macular degeneration. Genome-wide association studies have provided evidence that the immune system is involved in the pathogenesis of age-related macular degeneration; however, the role of inflammatory cytokines in CNV has not been established. In this study, we demonstrated that IL-17 had a strong potential for promoting neovascularization in a vascular endothelial growth factor–independent manner in laser-induced experimental CNV in mice. Infiltrated γδT cells and Thy-1+ innate lymphoid cells, but not Th17 cells, were the main sources of IL-17 in injured eyes. IL-23 was dispensable for IL-17 induction in the eye. Instead, we found that IL-1β and high-mobility group box 1 strongly promoted IL-17 expression by γδT cells. Suppression of IL-1β and high-mobility group box 1, as well as depletion of γδT cells, reduced IL-17 levels and ameliorated experimental CNV. Our findings suggest the existence of a novel inflammatory cytokine network that promotes neovascularization in the eye.
Mast Cells Recruited to Mesenteric Lymph Nodes during Helminth Infection Remain Hypogranular and Produce IL-4 and IL-6
Authors: Liu Anne Y. , Dwyer Dan F. , Jones Tatiana G. , Bankova Lora G. , Shen Shiliang , Katz Howard R. , Austen K. Frank , Gurish Michael F.
Published: January 2013

Mast cells (MC) and basophils share expression of the high-affinity receptor for IgE (FcεRI) but can be distinguished by their divergent expression of KIT and CD49b. In BALB/c mice, MC lineage cells expressing high levels of FcεRI by flow cytometry were seen only in bone marrow whereas those expressing intermediate levels of FcεRI were present in bone marrow and spleen of naive mice and in mesenteric lymph nodes (mLN) of Trichinella spiralis–infected mice. These FcεRI+KIT+CD49b− cells had a membrane phenotype similar to i.p. connective tissue-type MC, but were smaller and hypogranular by flow cytometry forward and side scatter profiles, respectively. Consistent with this, they lacked the prominent secretory granules identified by histochemistry and immunodetection for the MC-specific granule proteases that are readily seen in mature jejunal mucosal MC that also are induced by the infection and present at the same time. The concentration of these MC lineage cells in mLN determined by flow cytometry was comparable to that of MC progenitors (MCp) measured by limiting dilution and clonal expansion with maturation. We observed upregulation of IL-4 transcription by MCp in mLN and spleens of helminth-infected 4get mice, and we demonstrated by intracellular cytokine staining production of IL-4 and IL-6 by the mLN MCp in helminth-infected mice. Furthermore, treatment of helminth-infected mice with anti-FcεRI mAb, a protocol known to deplete basophils, also depleted mLN MCp. Thus, this study identifies a hypogranular subset of MCp recruited to mLN by helminth infection that may be an important unrecognized source of cytokines.
Role of Lumbar Drainage as an Adjunct for controlling Intracranial pressure in Acute Bacterial Meningitis
Authors: Gudmundsson G. , Oskarsdottir A.S. , Einarsdottir H.
Published: January 2013

This case report describes a 16-year-old girl with fulminant bacterial meningitis in whom external ventricular drainage and intense volume-targeted therapy (the Lund protocol) was not sufficient to control intracranial pressure, but lumbar drainage on day 8 decreased the intracranial pressure immediately and led to a sustained low intracranial pressure level. The case is unusual and not fully understood, but the authors assume that due to inflammation and tissue reactions following aggressive infection, cerebrospinal fluid could not flow freely from the posterior fossa up to the ventricular drain. High pressure in the posterior compartment maintained the high intracranial pressure measured by the ventricular drain, and lumbar drain insertion caused an immediate fall in pressure. The lesson learned is that during an intracranial pressure crisis in a patient with open basal cisterns, a lumbar drain may be necessary because the cerebrospinal fluid space can be compartmentalized.
How to support sensing capabilities in highly volatile situations
Authors: de Waard Erik J , Volberda Henk W , Soeters Joseph
Published: January 2013

In the scholarly debate on how to deal with hypercompetition, a dominant logic has become that investing in ‘sensing’, ‘seizing’, and ‘transforming’ dynamic capabilities offers organization’s the potential to repetitively initiate business innovations. Actual research into the micro-foundations of these dynamic capabilities has been limited. This study explores whether modular organizing and lateral coordination are typical processes that support an organization’s sensing function. Empirically the study investigates how these two variables help The Netherlands armed forces to deal with its volatile crisis response environment. The findings show that both predictors stimulate the development of a broad knowledge base from which the organization can operationally benefit. Yet, the study has also uncovered that, when modularity's demand of organizational autonomy is not sufficiently satisfied, the organization becomes preoccupied with its own internal functioning at the expense of its external lateral sensing capacity.
Openness to diversity, trust and conflict in multicultural organizations
Authors: Lauring Jakob , Selmer Jan
Published: January 2013

The purpose of this study was to explore the relation between openness to diversity in terms of linguist, visible, value and informational heterogeneity and group processes depicted by group trust and group conflict. We collected data using a web-based survey among 498 academics in multicultural departments. The departments were located in four different Danish universities. We found openness to value diversity and informational diversity to have a positive association with group trust and a negative association with group conflict. Openness to linguistic diversity had positive relationships with group trust. The findings of this study suggest that openness to diversity should be highly prioritized by human resource managers in demographically diverse organizations. Possible interventions include organizational culture change programs, diversity training at individual and team levels as well as rewarding group oriented behavior.
Person-organization fit and organizational citizenship behavior: Time perspective
Authors: Wei Yu-Chen
Published: January 2013

Viewing organizational citizenship behavior (OCB) engagement from the time cost perspective, this study not only investigates the direct effect of person—organization (P—O) fit on OCB but also examines the moderating effect of time evaluation on the effective magnitude of P—O fit on OCB. Specifically, I hypothesized that the positive relationship between P—O fit and OCB will be strengthened (weakened) if employees have a higher future (present) orientation time perspective. A sample of 262 bank financial specialists with supervisor-rated dependent variables is used to examine the hypothesized relationships. Research findings suggest that P—O fit can predict OCB engagement. I also found that time evaluation plays a moderating role in the relationship between P—O fit and OCB such that P—O fit will have a weaker predictive power if the employees have a higher present-orientation time perspective. The research results provide further understanding of why employees engage in OCB.
Information interests and exporting: The Spanish natural stone industry
Authors: Santos-Álvarez María-Valle , García-Merino María-Teresa
Published: January 2013

Export decisions depend on a wide variety of information stimuli. The current research focuses on the attention that international entrepreneurs (IEs) dedicate to different information stimuli relating to how the firm operates internationally, and examines whether the IE's attention varies in function of their experience and knowledge. For their empirical analysis, the authors study the information interests of the IEs in the Spanish natural stone industry. They identify three centres of interest: the strategic attractiveness of the foreign markets, barriers to exporting, and support programmes for exporters. The results show that the IEs are most interested in information about support programmes, and that is due to IEs with scant knowledge about the export markets. As the IEs accumulate knowledge about which are the main export markets, they become more interested in information about the strategic attractiveness of these markets. The authors conclude that a trade-off exists between the information about market attractiveness and the information about support programmes in the IE's attention. In contrast, attention towards export barriers behaves independently and depends on the IE's experience.
Organizational learning, innovation, and performance in KIBS
Authors: Santos-Vijande María Leticia , López-Sánchez José Ángel , González-Mieres Celina
Published: January 2013

There is widespread agreement that organizational learning (OL) and firms' innovative culture (innovativeness) positively influence organizational innovation (OI), which ultimately fosters long-term competitiveness. However, there is more limited empirical evidence on the role of OL as a forerunner of innovativeness, or on the combined effects of OL and innovativeness on OI and how performance is ultimately improved. In this research, OI is evaluated as a firm's actual ability to regularly adopt and implement more technical and administrative innovations with a greater degree of incorporated novelty relative to their main competitors. The aim is to approach innovation from a comprehensive viewpoint and to assess the attainment of superior competitive advantage in the innovation field. Effects on performance are evaluated at both the organizational level and in the commercialization of new services by means of two different conceptual model. These models are tested on a sample of 246 knowledge intensive business services (KIBS) located in Spain. We used polychoric correlations (Lee, Poon, & Bentler, 1995), together with a robust methodological approach, to analyze categorical variables in structural equation systems in EQS. The empirical results show that OL is an important antecedent for innovativeness, and that the latter plays a key role in the adoption of more technical and administrative innovations with a greater degree of incorporated novelty. Organizational learning exerts a direct effect on administrative innovation efforts although, contrary to previous research, the mediating role of innovativeness is required for the former to affect technical innovation. The research also supports the influence of OI on the attainment of competitive advantages at the business level and in the performance of new services. The greater ability of KIBS to innovate thus constitutes an invaluable resource to foster customer performance and profitability at the business level and in the commercialization of new service offerings.