bluuebunny/crossref_metadata_2025 huggingface dataset:
Mirtazapine add‐on therapy in the treatment of schizophrenia with atypical antipsychotics: a double‐blind, randomised, placebo‐controlled clinical trial
Authors: Berk Michael , Gama Clarissa S. , Sundram Suresh , Hustig Harry , Koopowitz Les , D'Souza Russell , Malloy Hamish , Rowland Cate , Monkhouse Alison , Monkhouse Andrew , Bole Fiona , Sathiyamoorthy Sumathy , Piskulic Danijela , Dodd Seetal
Published: March 2009

Objective

Schizophrenia is a multifaceted illness with positive, negative and cognitive symptom domains. Standard treatments often focus on positive symptoms and may not adequately relieve other symptoms. Previous studies have suggested a role for mirtazapine in schizophrenia, particularly in negative symptoms. This study investigates the efficacy of adding mirtazapine to treatment as usual to alleviate the negative symptoms of schizophrenia.

Methods

In a 6 week, double‐blind clinical trial, participants with a diagnosis of schizophrenia and currently being treated with atypical antipsychotic medication were randomised to adjunctive treatment with mirtazapine (30 mg/day) or placebo. The primary outcome measure was improvement in the Positive and Negative Syndrome Scale (PANSS). Measures of cognition, collected at baseline and week 6 only, were analysed using an Analysis of Covariance (ANCOVA) model. All other outcome measures were analysed using a linear mixed model.

Results

Forty participants were recruited to the study with equal numbers randomised to each treatment arm. There was no significant difference between mirtazapine and placebo treated participants for improvement in PANSS scores or any of the secondary outcome measures at any stage during the 6‐week trial.

Conclusions

This trial does not confirm previous research supporting the use of mirtazapine adjunctive to atypical antipsychotic treatment for schizophrenia. Copyright © 2009 John Wiley & Sons, Ltd.
Spatial assessment of hydrologic alteration across the Pearl River Delta, China, and possible underlying causes
Authors: Zhang Qiang , Xu Chong‐Yu , Chen Yongqin David , Yang Tao
Published: March 2009

The alterations of the water level across the Pearl River Delta (PRD) were investigated using a ‘range of variability approach’ (RVA) based on monthly water level datasets extracted from 17 gauging stations. A mapping method was used to illustrate the spatial patterns in the degrees of alteration of water levels. The results indicated that more stations showing moderate and high alterations in monthly mean maximum and minimum water levels when compared with monthly maximum and minimum water levels. River channels characterized by higher alterations of water levels were observed mainly in the regions north of 22° 30′N. Alterations of water levels across the PRD were a consequence of various influencing factors. However, changed hypsography due to extensive and intensive human activities, particularly the large‐scale dredging and excavation of the river sand, may be taken as one of the major causes for the substantial hydrologic alteration. This study indicated that the river channels characterized by altered water levels are mostly those characterized by highly and moderately intensive sand dredging. The changed ratio of the streamflow between Makou and Sanshui stations, the major upstream flow control stations, also influenced the water level alterations of the Pearl River delta. The results of this study will be of great significance in water resources management and better human mitigation of the natural hazards due to the altered water level under the changing environment. Copyright © 2009 John Wiley & Sons, Ltd.
Is Runx a linchpin for developmental signaling in metazoans?
Authors: Coffman James A.
Published: March 2009

The Runt domain (Runx) is a 128 amino acid sequence motif that defines a metazoan family of sequence‐specific DNA binding proteins, which appears to have originated in concert with the intercellular signaling systems that coordinate multicellular development in animals. In the model organisms where they have been studied (fruit fly, mouse, sea urchin, and nematode) Runx genes are essential for normal development, and in humans they are causally associated with a variety of cancers, manifesting both oncogenic and tumor suppressive attributes. During development Runx proteins support both cell proliferation and differentiation, and function in both transcriptional activation and repression. Runx function is thus context‐dependent, with the context provided genetically by cis‐regulatory sequence architecture and epigenetically by development. This context dependency makes it difficult to formulate reductionistic generalizations concerning Runx function in normal and carcinogenic development. However, a growing body of literature links Runx function to each of the major intercellular signaling systems in animals, suggesting that the general function of Runx transcription factors may be to potentiate and govern genomic responsiveness to developmental signaling. J. Cell. Biochem. 107: 194–202, 2009. © 2009 Wiley‐Liss, Inc.
Purification and characterization of solvent‐tolerant, thermostable, alkaline metalloprotease from alkalophilic Pseudomonas aeruginosa MTCC 7926
Authors: Patil Ulhas , Chaudhari Ambalal
Published: March 2009

BACKGROUND: Microbial proteases are becoming imperative for commercial applications. The protease secreted by Pseudomonas aeruginosa MTCC 7926, isolated from solvent‐contaminated habitat was purified and characterized for activity at various edaphic conditions. The purified alkaline protease was investigated for dehairing of animal skin, anti‐staphylococcal activity and processing of X‐ray film.

RESULTS: The protease was 24‐fold purified by ammonium sulfate fractionation, sephadex G‐100 gel filtration and DEAE‐cellulose, with 36% recovery. KM and Vmax, using casein were 2.94 mg mL−1 and 1.27 µmole min−1, respectively. The apparent molecular mass by SDS‐PAGE was 35 kDa. Alkaline protease was active at pH 6–11 and temperature 25–65 °C. Its activity was (a) 86.8% in 100 mmol L−1 NaCl, (b) >95% in metal ions (Mn2+, Ca2+, Mg2+, Fe2+) for 1 h, (c) >90% in bleaching agents and chemical surfactants, (d) 135.4 ± 2.0% and 119.9 ± 6.2% with rhamnolipid and cyclodextrin, respectively, (e) stable in solvents for 5–30 days at 27 °C, and (f) inhibited by EDTA, indicating metalloprotein.

CONCLUSION: This work showed that purified protease retained its activity in surfactants, solvents, metals, and bleaching agents. The enzyme is an alternative for detergent formulations, dehairing of animal skin, X‐ray film processing, treatment of staphylococcal infections and possibly non‐aqueous enzymatic peptide synthesis. Copyright © 2009 Society of Chemical Industry
Effect of surfactants and biomass on the gas/liquid mass transfer in an aqueous‐silicone oil two‐phase partitioning bioreactor using Rhodococcus erythropolis T902.1 to remove VOCs from gaseous effluents
Authors: Aldric Jean‐Marc , Gillet Sébastien , Delvigne Frank , Blecker Christophe , Lebeau Frédéric , Wathelet Jean‐Paul , Manigat Geralda , Thonart Philippe
Published: March 2009

BACKGROUND: The two‐phase partitioning bioreactor (TPPB) has become a new strategy for waste gas treatment. However, the impact of biomass and surfactants on gas/liquid (G/L) mass transfer needs to be better evaluated because the effects on the mass transfer coefficient KL and the interfacial area a, respectively, remains misunderstood.

RESULTS: This study showed that, first, the surfactant extract produced by Rhodococcus erythropolis reduced the surface hydrophobicity of the biomass. Secondly, an optimal concentration appeared to exist for both components, respectively 0.5 g L−1 and 0.7 g L−1 for biomass (B) and surfactant extract (SE) when the global mass transfer coefficient (KLa) of oxygen was measured in a silicone oil/water TPPB. However, the combination of B and SE was found to induce a negative synergism. In particular, SE improved the interfacial area a by increasing the bubble diameter, while B reduced it as soon as a concentration of 1 g L−1 was exceeded. In contrast, the SE acted negatively on the KL, while B improved it overall.

CONCLUSION: Better consideration is needed of the effect of biotic components in order to understand the phenomenon of G/L mass transfer in a TPPB. The behaviour of biomass growth and surfactants may strongly influence the mathematical models proposed in the literature. Copyright © 2009 Society of Chemical Industry
Reaction diastereoselectivity of chiral aminoalcohols/[Co(II)NO3]+ complexes in evaporating ESI nanodroplets: new insights from a joint experimental and computational investigation
Authors: Aschi Massimiliano , Fraschetti Caterina , Filippi Antonello , Speranza Maurizio
Published: March 2009

The nature of the ionic species, formed by electrospray ionization (ESI) of Co(NO3)2/CH3OH solutions with a pair of aminoalcohols W and Y, has been investigated by mass spectrometric and computational methods. Collision induced dissociation (CID) of ions, formally corresponding to the [WYCoNO3]+ structures, yields fragmentation patterns which reflect not only the expected [WYCoNO3]+ connectivity but also that of other isomeric structures. Formation of these latter species is observed only in the presence of a tertiary aminoalcohol, like N‐methylpseudoephedrine. The CID patterns are found to be strongly dependent on the chemical form (whether the free aminoalcohol or its hydrochloride), the configuration, and the relative concentration of the W and Y aminoalcohols. This variability parallels the results of classical MD (molecular dynamics) simulations of the [WYCoNO3]+ adducts which show a drastic alteration of the mechanical–dynamical features of the adducts by simply changing the charge state of W and/or Y, their absolute configuration, or by removing the solvent. The present experimental and computational study confirms the observation of fast stereoselective reactions in ESI nanodroplets before their evaporation and warns against any automatic correlation between the ESI spectrum of an analyte and its structure in solution. Copyright © 2009 John Wiley & Sons, Ltd.
A platinum agent resistance gene, POLB, is a prognostic indicator in colorectal cancer
Authors: Iwatsuki Masaaki , Mimori Koshi , Yokobori Takehiko , Tanaka Fumiaki , Tahara Koichiro , Inoue Hiroshi , Baba Hideo , Mori Masaki
Published: March 2009

Background

Recent progress in chemotherapy with platinum agents has improved clinical outcome in colorectal cancer (CRC), but there are no useful markers to predict the efficacy of such agents. DNA polymerase beta (POLB) mediates the efficacy of chemotherapy through DNA repair machinery. We analyzed the significance of POLB expression in CRC chemotherapy and its potential as a prognostic indicator.

Methods

Using microarray, POLB was found to be overexpressed in CRC cells compared with corresponding normal colon epithelial cells. We determined the susceptibility of POLB‐suppressed cells to cisplatin and oxaliplatin. We evaluated POLB mRNA expression in 97 CRC cases to determine the clinicopathologic significance of POLB expression.

Results

We found the suppression of POLB altered the in vitro susceptibility to cisplatin but not to oxaliplatin. In 97 CRC cases, lymph node metastasis, distant metastasis and TNM classification were significantly greater in the high POLB group than in the low group (P < 0.05). Patients with high POLB expression had significantly poorer prognosis than those with low expression (P < 0.05).

Conclusions

The data indicate POLB is overexpressed in CRC cases with high malignant potential. We suggest POLB could be useful as a predictive marker for selection of patients responsive to cisplatin. J. Surg. Oncol. 2009;100:261–266. © 2009 Wiley‐Liss, Inc.
Welding with High Power Diode Lasers
Authors: Venkat Sri
Published: March 2009

The new HighLight 1000F from Coherent is a fiber‐delivered, high power direct diode laser system for industrial metal fabrication uses. Specifically, this turnkey system produces 1 kW of high brightness output at 980 nm from a 600 μm core fiber having a numerical aperture of 0.22. This fiber, which is available in lengths from 5 m to 20 m, is terminated with an industry standard fiber connector making it compatible with common beam delivery accessories and process heads. This article provides an overview of the system's new possibilities.
Electrostatically‐driven Ordering in Model Dendrimer Polyelectrolytes: Effects of Concentration
Authors: Karatasos K. , Krystallis M.
Published: March 2009

In this study we extend our previous work in the self‐organization of dendrimer polyelectrolytes (Macromolecules, 2008, 41, 225) by examining the effects of dendrimer concentration and/or total volume fraction in the ordering process and the resulting structure, in the arrangement of counterions and dendrimer beads and in the diffusive motion of dendrimers at different strengths of Coulombic interactions. It is found that as long as the total volume fraction remains low (i.e. no jamming phenomena intervene) the symmetry of the resulted cubic phases is unaltered. At a higher volume fraction and at the strong electrostatic regime a kinetic arrest of the dendrimer molecules much in analogy to a colloidal glass‐like transition is observed, inhibiting thus the ordering process. Changes in the strength of electrostatic interactions and dendrimer concentration induces a systematic variation of the counterion ‐ counterion and the counterion ‐ charged‐dendrimer‐bead spatial arrangement. These findings are in qualitative agreement with previous studies in systems with very different structural details of the considered solutes, indicating a more general behaviour in charged macroion/counterion solutions.
Block Copolymer Micellisation in a Common Solvent Modeled by Self‐Consistent Field Calculations
Authors: Leermakers Frans A. M.
Published: March 2009

Summary: Recently it was shown that it is possible that block copolymers form micellar solutions in non‐selective solvents. Such micellisation is the result of a pure form of self‐assembly. A molecular realisation is given by asymmetric Poly‐(methacrylic acid)‐block‐Poly(ethylene oxide) copolymers (PMAA‐b‐PEO) in water at a pH < 5. As both the (short) methacrylic acid block and the (long) ethylene oxide are water soluble in the conditions used, it was concluded that the driving force is interchain hydrogen bonding between the PMAA and the PEO units. The mismatch in length of the blocks forces one block to accumulate at the micellar periphery and this eventually stops the phase separation process. We have performed self‐consistent field calculations to examine this scenario. With very reasonable parameters we are able to mimic the properties of these micelles, elaborate the pH dependence and confirm the trend found for the electrophoretic mobility. A nontrivial result of the calculations is that the ratio EO/MAA in the core is close to two.
Development and implementation of a physiotherapy intervention for use in a pragmatic randomized controlled trial in primary care for shoulder pain
Authors: Dziedzic Krysia , Stevenson Kay , Thomas Elaine , Sim Julius , Hay Elaine
Published: March 2009

Objective: To develop a package of physiotherapy treatment for a randomized controlled trial in primary care for shoulder pain and audit its use within the trial.

Methods: A survey of current physiotherapy approaches to the management of shoulder pain was conducted. The most frequently reported treatments were proposed as a package of care for a physiotherapy intervention in a trial of shoulder pain. The package was refined by a subgroup of 13 physiotherapists. For patients receiving the physiotherapy intervention in the main trial (n = 98), the frequency of use of modalities over the treatment period was calculated by percentages of modality usage per number of patient contacts. Treatment details were recorded by the physiotherapist at each patient visit.

Results: The physiotherapy intervention included passive movements/mobilizations, active movement/mobilizations, a home exercise programme, education and advice, and ultrasound. The most frequently used modality at the assessment visit was the standardized education and advice leaflet for shoulder pain (85%) followed by the home exercise programme (79%), which was reinforced throughout the trial treatment course. The most frequently used modalities over the treatment period were ultrasound (42%), active mobilizations (41%) and passive mobilizations (41%). The mean number of trial treatment visits was 6.2 (SD: 2.1; range 1–8). Additional trial treatments (1–8) were delivered to 12 patients. Eighty‐five patients were given only one therapeutic diagnosis, and 13 were given two. The most common diagnoses were tendonitis (32%) and capsulitis (25%). Pain was the major problem in 78% of patients, 15% had stiffness and 7% of patients reported both pain and stiffness.

Conclusions: Physiotherapists complied well with the trial protocol. Few treatments were used in isolation. This report demonstrates how physiotherapists can agree and deliver a standardized package of treatment, which reflects current practice, as part of a randomized controlled trial. Copyright © 2009 John Wiley & Sons, Ltd.
Investigation of electrorheological properties and creep behavior of poly(oxymethylene)/polythiophene composites
Authors: Eyrik Mehtap , Yavuz Mustafa , Unal H. Ibrahim , Sari Bekir
Published: March 2009

In this study, electrorheological (ER) properties of polythiophene (PT) and poly(oxymethylene)/polythiophene (POM/PT), conducting composites having different compositions were investigated. The particle sizes of the composites were measured by dynamic light scattering method. Conductivities and dielectric properties of these composites were determined. Suspensions of PT and POM/PT composites were prepared in silicone oil (SO) at several concentrations (c = 5–25%, m/m) and their sedimentation stabilities were determined. The flow times of these suspensions at various dc electric field strengths were measured. The effects of dispersed particle concentration, particle size, shear rate, electric field strength, frequency, and temperature onto ER activities of these suspensions were investigated. Further, creep tests were applied to the composite suspensions and reversible viscoelastic deformations observed. POLYM. COMPOS., 2009. © 2009 Society of Plastics Engineers
Fatigue delamination, initiation, and growth, under mode I and II of fracture in a carbon‐fiber epoxy composite
Authors: Argüelles Antonio , Viña Jaime , Canteli Alfonso F. , Bonhomme Jorge
Published: March 2009

In this article, interlaminar crack initiation and propagation under mode I and II dynamic loading of an epoxy matrix reinforced with unidirectional carbon fibers were evaluated. Delamination in mode I was carried out employing the DCB test (Double Cantilever Beam). In mode II, the ENF test (End Notched Flexure) was used. The fracture toughness in mode I was obtained using the methods of the ASTM D5528 Standard, whereas in mode II, the methods were applied in accordance with the ESIS (European Structural Integrity Society) Protocol. Employing this experimental program, the fatigue curves (ΔG,N) and growth rate curves (ΔG, da/dN) in both fracture modes were determined for an asymmetry ratio R = 0.2. The influence of the manufacturing process of the material on its behavior with respect to crack growth onset may be deduced from the experimental results, mainly the presence of resin bags. Moreover, as the crack growth rate decreases for large crack lengths, crack growth may even cease if the critical fracture energy does not increase above the values obtained in the static characterization of the material. POLYM. COMPOS., 2010. © 2009 Society of Plastics Engineers
The influence of the compatibilizer on the morphology and thermal properties of polypropylene‐layered double hydroxide composites
Authors: Coiai Serena , Passaglia Elisa , Hermann Alexandra , Augier Sylvain , Pratelli Daniele , Streller Rouven C.
Published: March 2009

Polypropylene (PP)/layered double hydroxide (LDH) composites were prepared via melt‐compounding using both a carbonate‐LDH and an organo‐LDH (dodecyl benzene sulfonate DBS‐LDH) in different concentrations. Transmission electron microscopy and X‐ray diffraction analysis were used to investigate the morphology. The results showed that only by using DBS‐LDH the intercalation of polymer chains and a partial delamination were obtained. However, the introduction of maleic anhydride‐grafted polypropylene (PP‐g‐MAH), as coupling agent, favored the aggregation of the particles generating localized domains of aggregates. The thermo‐gravimetric analysis showed that PP/DBS‐LDH composites have a higher thermal stability than the pure matrix. Differential scanning calorimetry evidenced that both LDH and DBS‐LDH particles acted as nucleating agents increasing the crystallization temperature, even if, in the case of LDH the effect was observed only with the addition of the compatibilizer. The results collected by dynamic mechanical thermal analysis, beyond showing a significant increase of the matrix stiffness by incorporation of DBS‐LDH, evidenced an increase of the PP glass transition temperature (Tg) indicating a restriction of PP chain segment mobility due to the strong polymer‐particle interactions. POLYM. COMPOS., 2010. © 2009 Society of Plastics Engineers
Proteomic analysis of the bacterial pathogen Bartonella henselae and identification of immunogenic proteins for serodiagnosis
Authors: Eberhardt Christian , Engelmann Susanne , Kusch Harald , Albrecht Dirk , Hecker Michael , Autenrieth Ingo B. , Kempf Volkhard A. J.
Published: March 2009

Bartonella henselae is a slow growing, fastidious and facultative intracellular pathogen causing cat scratch disease and vasculoproliferative disorders. To date, knowledge about the pathogenicity of this human pathogenic bacterium is limited and, additionally, serodiagnosis still needs further improvement. Here, we investigated the proteome of B. henselae using 2‐D SDS‐PAGE and MALDI‐TOF‐MS. We provide a comprehensive 2‐D proteome reference map of the whole cell lysate of B. henselae with 431 identified protein spots representing 191 different proteins of which 16 were formerly assigned as hypothetical proteins. To unravel immunoreactive antigens, we applied 2‐D SDS‐PAGE and subsequent immunoblotting using 33 sera of patients suffering from B. henselae infections. The analysis revealed 79 immunoreactive proteins of which 71 were identified. Setting a threshold of 20% seroreactivity, 11 proteins turned out to be immunodominant antigens potentially useful for an improved Bartonella‐specific serodiagnosis. Therefore, we provide for the first time (i) a comprehensive 2‐D proteome map of B. henselae for further proteome‐based studies focussed on the pathogenicity of B. henselae and (ii) an integrated view into the humoral immune responses targeted against this newly emerged human pathogenic bacterium.
Comparative proteomic profile of rat sciatic nerve and gastrocnemius muscle tissues in ageing by 2‐D DIGE
Authors: Capitanio Daniele , Vasso Michele , Fania Chiara , Moriggi Manuela , Viganò Agnese , Procacci Patrizia , Magnaghi Valerio , Gelfi Cecilia
Published: March 2009

Ageing induces a progressive morphological change and functional decline in muscles and in nerves. Light and electron microscopy, 2‐D DIGE and MS, were applied to profile the qualitative and quantitative differences in the proteome and morphology of rat gastrocnemius muscle and sciatic nerve, in healthy 22‐month‐old rats. At muscle level, morphological changes are associated to fibre atrophy accompanied by myofibrillar loss and degeneration, disappearance of sarcomeres and sarcoplasmic reticulum dilatation, internal migration of nuclei, longitudinal fibre splitting, increment of subsarcolemmal mitochondria aggregates and increment of lipofuscin granules. Sciatic nerve shows myelin abnormalities like enfoldings, invaginations, onion bulbs, breakdowns and side axonal atrophy. Proteomic analysis identified changes correlated to morphological abnormalities in metabolic, contractile and cytoskeletal proteins, deregulation of iron homeostasis, change of Ca2+ balance and stress response proteins, accompanied by a deregulation of myelin membrane adhesion protein and proteins regulating the neuronal caliber. By comparing proteomic results from the two tissues, 16 protein isoforms showed the same up and down regulation trend suggesting that there are changes implying a general process which may act as a signal event of degeneration. Only β enolase and tropomyosin 1α were differentially expressed in the tissues.
High‐throughput screening of Erwinia chrysanthemi pectin methylesterase variants using carbohydrate microarrays
Authors: Øbro Jens , Sørensen Iben , Derkx Patrick , Madsen Christian T. , Drews Martin , Willer Martin , Mikkelsen Jørn D. , Willats William G. T.
Published: March 2009

Pectin methylesterases (PMEs) catalyse the removal of methyl esters from the homogalacturonan (HG) backbone domain of pectin, a ubiquitous polysaccharide in plant cell walls. The degree of methyl esterification (DE) impacts upon the functional properties of HG within cell walls and plants produce numerous PMEs that act upon HG in muro. Many microbial plant pathogens also produce PMEs, the activity of which renders HG more susceptible to cleavage by pectin lyase and polygalacturonase enzymes and hence aids cell wall degradation. We have developed a novel microarray‐based approach to investigate the activity of a series of variant enzymes based on the PME from the important pathogen Erwinia chrysanthemi. A library of 99 E. chrysanthemi PME mutants was created in which seven amino acids were altered by various different substitutions. Each mutant PME was incubated with a highly methyl esterified lime pectin substrate and, after digestion the enzyme/substrate mixtures were printed as microarrays. The loss of activity that resulted from certain mutations was detected by probing arrays with a mAb (JIM7) that preferentially binds to HG with a relatively high DE. Active PMEs therefore resulted in diminished JIM7 binding to the lime pectin substrate, whereas inactive PMEs did not. Our findings demonstrate the feasibility of our approach for rapidly testing the effects on PME activity of substituting a wide variety of amino acids at different positions.
A comprehensive Plasmodium falciparum protein interaction map reveals a distinct architecture of a core interactome
Authors: Wuchty Stefan , Adams John H. , Ferdig Michael T.
Published: March 2009

We derive a map of protein interactions in the parasite Plasmodium falciparum from conserved interactions in Saccharomyces cerevisiae, Caenorhabditis elegans, Drosophila melanogaster, and Escherichia coli and pool them with experimental interaction data. The application of a clique‐percolation algorithm allows us to find overlapping clusters, strongly correlated with yeast specific conserved protein complexes. Such clusters contain core activities that govern gene expression, largely dominated by components of protein production and degradation processes as well as RNA metabolism. A critical role of protein hubs in the interactome of P. falciparum is supported by their appearance in multiple clusters and the tendencies of their interactions to reach into many distinct protein clusters. Parasite proteins with a human ortholog tend to appear in single complexes. Annotating each protein with the stage where it is maximally expressed we observe a high level of cluster integrity in the ring stage. While we find no signal in the trophozoite phase, expression patterns are reversed in the schizont phase, implying a preponderance of parasite specific functions in this late, invasive schizont stage. As such, the inference of potential protein interactions and their analysis contributes to our understanding of the parasite, indicating basic pathways and processes as unique targets for therapeutic intervention.
Analysis of the periplasmic proteome of Pseudomonas aeruginosa, a metabolically versatile opportunistic pathogen
Authors: Imperi Francesco , Ciccosanti Fabiola , Perdomo Ariel Basulto , Tiburzi Federica , Mancone Carmine , Alonzi Tonino , Ascenzi Paolo , Piacentini Mauro , Visca Paolo , Fimia Gian Maria
Published: March 2009

The Gram‐negative bacterium Pseudomonas aeruginosa is a main cause of infection in hospitalized, burned, immunocompromised, and cystic fibrosis patients. Many processes essential for P. aeruginosa pathogenesis, e.g., nutrient uptake, antibiotic resistance, and virulence, take place in the cell envelope and depend on components residing in the periplasmic space. Recent high‐throughput studies focused on P. aeruginosa membrane compartments. However, the composition and dynamics of its periplasm remain largely uncharacterized. Here, we report a detailed description of the periplasmic proteome of the wild‐type P. aeruginosa strain PAO1 by 2‐DE and MALDI‐TOF/TOF analysis. Three extraction methods were compared at proteome level in order to achieve the most reliable and comprehensive periplasmic protein map. A total of 495 spots representing 395 different proteins were identified. Most of the high intensity spots corresponded to periplasmic proteins, while cytoplasmic contaminants were mainly detected among faint spots. The majority of the identified periplasmic proteins is involved in transport, cell‐envelope integrity, and protein folding control. Notably, more than 30% still has an unpredicted function. This work provides the first overview of the P. aeruginosa periplasm and offers the basis for future studies on periplasmic proteome changes occurring during P. aeruginosa adaptation to different environments and/or antibiotic treatments.
Properties modification of PET vascular prostheses
Authors: Chaouch W. , Dieval F. , Chakfe N. , Durand B.
Published: March 2009

Aging mechanisms have been investigated on polyethylene terephthalate (PET) fibres extracted from various vascular prostheses in order to identify the different modifications of the material's degradation. NMR spectroscopy provides a comprehensive view of chemical structures of macromolecules. Examination of a series of PET fibres showed significant chemical differences between the virgin prostheses and the explants, especially for diethylene glycol (DEG) and cyclic oligomeric groups. These analyses revealed that PET failures in vascular prostheses are susceptible to hydrolysis during in vivo stay. We also extended this 1H NMR technique to determine the hydroxyl and carboxyl end‐group concentrations. In order to validate the 1H NMR results, complementary techniques — chemical titration and classical viscosimetry — were used. The obtained results showed an increase in end‐group concentrations and a decrease of the viscosity averaged macromolecular weight (Mν) for the explants. Copyright © 2009 John Wiley & Sons, Ltd.
Role of sorption and degradation in the herbicidal function of isoxaflutole
Authors: Sims Gerald K , Taylor‐Lovell Sarah , Tarr Gabe , Maskel Shawn
Published: March 2009

BACKGROUND: The fate of isoxaflutole (IFT) in soil is closely related to soil sorption. Sorption and transformation of IFT were investigated in laboratory incubations with four soils, and these results were used to interpret greenhouse studies using IFT to control several weed species.

RESULTS: Degradation proceeded by previously observed pathways to form diketonitrile (DKN) and benzoic acid (BA) derivatives, as well as traces of unidentified products. Over the course of the incubation, DKN was the dominant active form of the herbicide present in the experimental system, and was thus critical to the soil activity of the herbicide for weed control.

CONCLUSION: Control of most weed species appeared to be a function of both sorption and biodegradation of DKN, with greatest weed control being observed in soils in which a significant portion of the DKN that was formed persisted and remained bioavailable over the course of the incubation. Copyright © 2009 Society of Chemical Industry
New developments in green LEDs
Authors: Peter Matthias , Laubsch Ansgar , Bergbauer Werner , Meyer Tobias , Sabathil Matthias , Baur Johannes , Hahn Berthold
Published: March 2009

Green InGaN LEDs showed great improvements over the last decade, but still perform not as good as blue InGaN LEDs. Brightness, Efficiency and sub‐linearity of brightness versus driving current (“droop”) are significantly lower for a 530 nm green LED than for a 440 nm blue LED. Assuming an indirect Auger effect as one of the major loss mechanisms in InGaN LEDs, a reduction of the carrier density per emitting well is the key for efficiency improvement for green LEDs. An optimized multiple quantum well (MQW) structure with multiple emitting wells at 525 nm is compared to a single quantum well LED structure. A color‐coding scheme was used to investigate MQW operation: up to four MQWs contribute to the green emission at 525 nm. Packaged 1 × 1 mm2 ThinGaN® chips emit up to 109 lm (209 mW) at 350 mA and 170 lm (339 mW) at 700 mA, the efficacy was 90 lm/W and 66 lm/W, respectively. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Modulation spectroscopy of InAs semiconductor nanostructures grown on (631) high index substrates
Authors: Méndez‐García Victor H. , Martínez‐Velis I. , Rojas‐Ramirez J. S. , Contreras‐Guerrero R. , Ramírez‐Lopez M. , Hernandez‐Rosas J. , Garcia‐Liñan G. , Gorbatchev A. Yu. , Zamora‐Peredo L. , López‐López M.
Published: March 2009

The molecular beam epitaxial (MBE) growth of InAs nanostructures on GaAs(631)‐oriented substrates is studied by photoluminescence (PL) and photoreflectance spectroscopy (PR). First, a corrugated surface conformed by regularly spaced grooves aligned along the [$ \bar 5 $93] azimuth was formed by the GaAs homoepitaxial growth on the (631) substrate. On this template, we proceeded with the deposition of InAs at several thicknesses in the range of 1 to 4.5 monolayers (MLs). An atomic force microscopy (AFM) analysis of samples without GaAs capping, revealed that assemblage of QDs occurs only after the deposition of the equivalent to ∼1.9 ML of InAs. On these samples, we observed changes on the PR line‐shape in the near‐bandgap GaAs region linked to the quantity of InAs deposited. The intensity of the built in electric fields was correlated with the strain state at the heterointerface, as a consequence of the self induced piezoelectric effect, typical from high index surfaces. On the other hand, when the samples were capped with a 100 Å thick GaAs layer, strong emission of the nanostructures occurs even for deposited quantities of InAs as low as 1 ML. Since for this InAs thickness the self‐assemblage of QDs is not observed, the optical transitions observed were associated with the optical emission of self assembled semiconductor quantum wires, promoted by surface diffusion anisotropy, characteristic of the (631) plane. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Multi‐decker sandwich complexes using Be32− and Mg32− dianions
Authors: Chattaraj P. K. , Giri S.
Published: March 2009

Global and local reactivity descriptors as well as the nucleus independent chemical shift values of different multi‐decker sandwich complexes involving Be32− and Mg32− dianions are calculated at the B3LYP/6‐311+G* level of theory. Important insights into their bonding, reactivity, and aromaticity are obtained through this study. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
Transferability of the venture capital model to the corporate context: Implications for the performance of corporate venture units
Authors: Hill Susan A. , Maula Markku V. J. , Birkinshaw Julian M. , Murray Gordon C.
Published: March 2009

While recent literature has advocated the transfer of venture capital (VC) practices and structures to corporate venture (CV) units, the wisdom of this advice has not been subject to rigorous empirical scrutiny. We test the implications of the VC model for CV unit performance using a longitudinal database combining survey, archival, and survival data on 95 CV units. VC model elements of high‐powered incentives, autonomous organization, investment syndication, investment staging, and specialization were each associated with higher CV unit performance. Critically, different elements of the VC model predicted improvements in either strategic or financial performance in CV units. Survival of the CV unit was strongly associated with employing the VC model, partially mediated by enhanced performance. Copyright © 2009 Strategic Management Society.
Self‐selection, endogeneity, and the relationship between CEO duality and firm performance
Authors: Iyengar Raghavan J. , Zampelli Ernest M.
Published: March 2009

This study focuses explicitly on the methodological implications of the endogenous theory of governance as applied to firm performance. In particular, if firms choose their governance structures as part of a constrained performance maximization process, then application of an appropriate empirical methodology should reveal statistical evidence of such behavior. In this study we take advantage of the endogenous switching regression model framework to determine whether such predicted optimizing behavior can be corroborated by the data. The model allows us to test explicitly for selection behavior in accordance with comparative advantage and, concomitantly, the presence of selectivity bias, in estimating the impact of CEO duality on firm performance. The selection and performance equations are modeled in accordance with the extant accounting, economics, and management literature on the impact of the dual governance structure on firm performance. Overall, we tested four performance measures for the entire sample of firm‐year observations as well as for the largest three industries in terms of sample sizes. The major finding, robust in all cases, is that there is no evidence to support a contention that CEO duality is a structure purposefully chosen for optimizing performance. If firms are indeed choosing the dual leadership structure, they are doing so for reasons other than improving performance from what it would be otherwise. In fact, for performance measured as market return and earnings per share, there is evidence of a significant selectivity bias that acts to lower performance below what it would have been under random assignment. For performance measured by Tobin's q and return on assets, we found neither evidence of selectivity bias, nor any significant marginal performance impacts of CEO duality. Such findings are inconsistent with an endogenous governance theory, at least when applied to firm performance. Copyright © 2009 John Wiley & Sons, Ltd.
A novel wideband space‐time channel simulator based on the geometrical one‐ring model with applications in MIMO‐OFDM systems
Authors: Zhang Haixia , Yuan Dongfeng , Pätzold Matthias , Wu Yi , Nguyen Van Duc
Published: March 2009

In this paper, we extend the geometrical one‐ring multiple‐input multiple‐output (MIMO) channel model with respect to frequency selectivity. Our approach enables the design of efficient and accurate simulation models for wideband space‐time MIMO channels under isotropic scattering conditions. Two methods will be provided to compute the parameters of the simulation model. Especially, the temporal, frequency and spatial correlation properties of the proposed wideband space‐time MIMO channel simulator are studied analytically. It is shown that any given specified or measured discrete power delay profile (PDP) can be incorporated into the simulation model. The high accuracy of the simulation model is demonstrated by comparing its statistical properties with those of the underlying reference model with specified correlation properties in the time, frequency and spatial domain. As an application example of the new MIMO frequency‐selective fading channel model, we study the influence of various channel model parameters on the system performance of a space‐time coded orthogonal frequency division multiplexing (OFDM) system. For example, we investigate the influence of the antenna element spacings of the base station (BS) antenna as well as the mobile station (MS) antenna. It turns out that an increasing of the antenna element spacing at the BS side results in a higher diversity gain than an increasing of the antenna element spacing at the MS side. Furthermore, the diversity gain brought in by space‐time block coding schemes is investigated by simulation. Our results show that transmitter diversity can significantly reduce the symbol error rate (SER) of multiple antenna systems. Finally, the influence of the Doppler effect and the impact of imperfect channel state information (CSI) on the system performance is also investigated. Copyright © 2009 John Wiley & Sons, Ltd.
Sustainability of gains made in a primary school HIV prevention programme in Kenya into the secondary school years
Authors: Maticka‐Tyndale Eleanor
Published: March 2009

The question addressed in this paper is whether the beneficial effects of Primary School Action for Better Health (PSABH), an HIV prevention programme delivered in Kenyan primary schools, continue once students move on to secondary schools. Questionnaires were completed in December 2005 and January 2006 by all form 1–3 students in 154 randomly selected secondary schools. Students who had attended primary schools with PSABH programming were compared to those who did not on knowledge, attitudes and behaviours using multivariate regression with controls for gender, school year, religion and financial resources. Students who attended PSABH primary schools were significantly more likely to have higher levels of knowledge and attitudes that were more supportive of sexual restraint, condom use and HIV testing. They were more likely to have used several safer sex practices and to have been tested for HIV. The effects were strongest in the first year of secondary school and decreased thereafter. PSABH continues to have a beneficial effect for students who continue to secondary school.
SGS3 and RDR6 interact and colocalize in cytoplasmic SGS3/RDR6‐bodies
Authors: Kumakura Naoyoshi , Takeda Atsushi , Fujioka Yoichiro , Motose Hiroyasu , Takano Ryo , Watanabe Yuichiro
Published: March 2009

MINT‐7014697: RDR6 (uniprotkb:Q9SG02) and SGS3 (uniprotkb:Q9LDX1) colocalize (MI:0403) by fluorescence microscopy (MI:0416)
Oil and gas pools: the fundamentals of formation, prospecting, and exploitation
Authors: Nesterov I.I.
Published: March 2009

The paper deals with the main fundamental problem of oil and gas geology—compilation of a theoretical basis and elucidation of the mechanism of hydrocarbon pool formation. The temperature factor determining this mechanism is insufficient for the breaking of carbon–carbon bonds in organic molecules. It is shown that this process is provoked by the internal energy of the subsurface organic matter determined by unpaired electrons surrounding carbon nuclei. In natural processes, this phenomenon is realized as a result of sedimentary-rock consolidation on the subsidence of sedimentation basins, during subhorizontal microdislocations measured via Poisson’s ratio and Protod’yakonov “arch”. This effect can be reached on hydrofracturing. A possibility of fluid hydrocarbon migration beyond the modern-day oil and gas pools is discussed, thus demonstrating that there are no traces that would suggest oil migration. Hydrocarbon pools have been revealed in clayey rocks, both bituminous and OM-poor. It is shown that the exploitation of a new type of reservoir (bazhenite) with natural hydrocarbon pools as well as technogenic (newly formed) oil and gas pools in clayey, clay-siliceous, siliceous, clay-carbonate, and clay-siliceous-carbonate bituminous rocks will significantly increase oil production in West Siberia.
Vertical zoning of oil and gas formation: historico-genetic aspects
Authors: Safronov A.F.
Published: March 2009

Considerable variations in depth zoning of dispersed organic matter (DOM) catagenesis are caused by various physical and geological factors. The evolution of a sedimentary basin (SB) implies successive changes in organization levels of this system. In the process of evolution the system structure is determined by the interaction of its subsystems. Any parameter of an SB (physical properties of rocks, degree of OM catagenesis, temperature, formation pressure, phase ratio of hydrocarbons) is governed by the processes running in the system. Variations of these parameters in space and time characterize the structure of the changing system. The intensity of lithification of terrigenous rocks, OM catagenesis, and HC generation in time is approximated by a curvilinear relation, which becomes asympthotic at a particular stage. In other words, these processes drastically decay 150±50 Myr after the main sedimentation had completed. For an SB system with a natural set of main subsystems (mineral, water, organic, hydrocarbon), the age is less important (at least throughout the Phanerozoic) than the duration of the process. Analysis is given to the formation of vertical HC zoning, which includes all the processes observable within an SB. The relationship of events and qualitative temporal and spatial changes during these processes is considered.
The geodynamic evolution of the folded framing and the western margin of the Siberian craton in the Neoproterozoic: geological, structural, sedimentological, geochronological, and paleomagnetic data
Authors: Vernikovsky V.A. , Kazansky A.Yu. , Matushkin N.Yu. , Metelkin D.V. , Sovetov J.K.
Published: March 2009

The formation of the western margin of the Siberian craton in the Neoproterozoic is considered, with a focus on its transformation from a passive continental margin into an active one, accretion and collision processes, formation of island arcs and ophiolites, orogeny, and continent-marginal rifting. The evolution and correlation of sedimentary basins within fold-thrust belts of the Siberian Platform framing are considered. New structural and kinematic data on the Yenisei fault zone are discussed. On the basis of paleomagnetic data obtained for the structures in the zone of junction of the Siberian Platform and the West Siberian Plate, new models are proposed for the location of the Siberian craton relative to other paleocontinents and microcontinents in the Neoproterzoic. All these data provide a consistent evolution scheme for the western margin of the Siberian paleocontinent in the Neoproterozoic and constrain the position of the Siberian craton margin in Late Neoproterozoic (pre-Vendian) time.
Comparative Genomic Study Reveals a Transition from TA Richness in Invertebrates to GC Richness in Vertebrates at CpG Flanking Sites: An Indication for Context-Dependent Mutagenicity of Methylated CpG Sites
Authors: Wang Yong , Leung Frederick C.C.
Published: March 2009

Vertebrate genomes are characterized with CpG deficiency, particularly for GC-poor regions. The GC content-related CpG deficiency is probably caused by context-dependent deamination of methylated CpG sites. This hypothesis was examined in this study by comparing nucleotide frequencies at CpG flanking positions among invertebrate and vertebrate genomes. The finding is a transition of nucleotide preference of 5′ T to 5′ A at the invertebrate-vertebrate boundary, indicating that a large number of CpG sites with 5′ Ts were depleted because of global DNA methylation developed in vertebrates. At genome level, we investigated CpG observed/expected (obs/exp) values in 500 bp fragments, and found that higher CpG obs/exp value is shown in GC-poor regions of invertebrate genomes (except sea urchin) but in GC-rich sequences of vertebrate genomes. We next compared GC content at CpG flanking positions with genomic average, showing that the GC content is lower than the average in invertebrate genomes, but higher than that in vertebrate genomes. These results indicate that although 5′ T and 5′ A are different in inducing deamination of methylated CpG sites, GC content is even more important in affecting the deamination rate. In all the tests, the results of sea urchin are similar to vertebrates perhaps due to its fractional DNA methylation. CpG deficiency is therefore suggested to be mainly a result of high mutation rates of methylated CpG sites in GC-poor regions.