bluuebunny/crossref_metadata_2025 huggingface dataset:
Formation of sprite streamers at subbreakdown conditions from ionospheric inhomogeneities resembling observed sprite halo structures
Authors: Kosar Burcu C. , Liu Ningyu , Rassoul Hamid K.
Published: November 2013

Modeling results of sprite streamer formation from large ionospheric inhomogeneities or patches (several tens to hundreds of meter wide) indicate that positive streamers can be initiated at subbreakdown conditions from the inhomogeneities with a density comparable to sprite halo densities. For spherical patches with a given radius, the minimum density required for streamer initiation decreases with increasing ambient field. For a given density, the minimum size of the inhomogeneity decreases with increasing ambient field. The modeling results on the associated optical emissions show that a luminous spherical‐like cap appears around the lower tip of the ionization patch before streamer initiation, and the streamer is initiated from the bottom of this cap, which appears to be similar to streamer initiation from luminous structures in the lower ionosphere recorded by recent high‐speed videos. Our study suggests that if the sprite halo front is unstable, inhomogeneities developing from it can initiate sprite streamers at subbreakdown conditions.
TETRA observation of gamma‐rays at ground level associated with nearby thunderstorms
Authors: Ringuette Rebecca , Case Gary L. , Cherry Michael L. , Granger Douglas , Guzik T. Gregory , Stewart Michael , Wefel John P.
Published: November 2013

Terrestrial gamma‐ray flashes (TGFs)—very short, intense bursts of electrons, positrons, and energetic photons originating from terrestrial thunderstorms—have been detected with satellite instruments. TGF and Energetic Thunderstorm Rooftop Array (TETRA), an array of NaI(Tl) scintillators at Louisiana State University, has now been used to detect similar bursts of 50 keV to over 2 MeV gamma‐rays at ground level. After 2.6 years of observation, 24 events with durations 0.02–4.2 ms have been detected associated with nearby lightning, three of them coincident events observed by detectors separated by ~1000 m. Nine of the events occurred within 6 ms and 5 km of negative polarity cloud‐to‐ground lightning strokes with measured currents in excess of 20 kA. The events reported here constitute the first catalog of TGFs observed at ground level in close proximity to the acceleration site.
Sensitivity of the atmospheric response to warm pool El Niño events to modeled SSTs and future climate forcings
Authors: Hurwitz Margaret M. , Garfinkel Chaim I. , Newman Paul A. , Oman Luke D.
Published: November 2013

Warm pool El Niño (WPEN) events are characterized by positive sea surface temperature (SST) anomalies in the central equatorial Pacific. Under present‐day climate conditions, WPEN events generate poleward propagating wavetrains and enhance midlatitude planetary wave activity, weakening the stratospheric polar vortices. The late 21st century extratropical atmospheric response to WPEN events is investigated using the Goddard Earth Observing System Chemistry‐Climate Model (GEOSCCM), version 2. GEOSCCM simulations are forced by projected late 21st century concentrations of greenhouse gases (GHGs) and ozone‐depleting substances (ODSs) and by SSTs and sea ice concentrations from an existing ocean‐atmosphere simulation. Despite known ocean‐atmosphere model biases, the prescribed SST fields represent a best estimate of the structure of late 21st century WPEN events. The future Arctic vortex response is qualitatively similar to that observed in recent decades but is weaker in late winter. This response reflects the weaker SST forcing in the Niño 3.4 region and subsequently weaker Northern Hemisphere tropospheric teleconnections. The Antarctic stratosphere does not respond to WPEN events in a future climate, reflecting a change in tropospheric teleconnections: The meridional wavetrain weakens while a more zonal wavetrain originates near Australia. Sensitivity simulations show that a strong poleward wavetrain response to WPEN requires a strengthening and southeastward extension of the South Pacific Convergence Zone; this feature is not captured by the late 21st century modeled SSTs. Expected future increases in GHGs and decreases in ODSs do not affect the polar stratospheric responses to WPEN.
Characterization of high‐latitude ionospheric scintillation of GPS signals
Authors: Jiao Yu , Morton Yu T. , Taylor Steven , Pelgrum Wouter
Published: November 2013

This paper presents statistical analysis of arctic auroral oval ionospheric scintillation events during the current solar maximum based on high‐rate Global Positioning System data collected in Gakona, Alaska (62.39°N, 145.15°W) from August 2010 to March 2013. The objective is to gain a better understanding of the climatology and morphology of ionospheric scintillation in high‐latitude regions. A scintillation event filter, multipath identification procedures, and other processes are applied to exclude nonscintillation related signal intensity and phase fluctuation and to extract scintillation events with S4 index above 0.12 and phase sigma above 6° from over 657 days of data. A total of over 5800 scintillation events were identified; most of them show phase fluctuations, only 10% of the phase fluctuations are accompanied by weak amplitude scintillation. Based on the occurrence time, signal direction of arrival, intensity, and duration of these scintillation events and the solar and geomagnetic activities associated with these events, diurnal, seasonal, spatial, and solar activity dependencies are derived and presented in the paper.
Synthesis and Properties of Branched Oligo(2‐thienyl)‐ and Oligo(2,2′‐bithien‐5‐yl)‐Substituted Pyridine Derivatives
Authors: Bera Mrinal K. , Gholap Shivajirao L. , Hommes Paul , Neuthe Katja , Trawny Daniel , Rabe Jürgen P. , Lentz Dieter , Zimmer Reinhold , Reissig Hans‐Ulrich
Published: November 2013

Starting from easily accessible precursors we describe the preparation of a series of branched oligo(2‐thienyl)‐ and oligo(2,2′‐bithienyl)‐substituted pyridine derivatives. With palladium‐catalyzed cross‐coupling reactions of pyridyl nonaflates/triflates as key steps we synthesized 2,6‐di(2‐thienyl)pyridines bridged by thiophene or benzene rings. By selective bromination of 2,6‐di(2‐thienyl)pyridine and 2,4,6‐tri(2‐thienyl)pyridine and subsequent coupling reactions an access to oligo(2,2′‐bithien‐5‐yl)‐substituted pyridine derivatives was gained. The constitution and solid state conformation of 2,6‐bis(2,2’‐bithien‐5‐yl)pyridine was determined by X‐ray analysis. This series of new pyridine‐thiophene conjugates was systematically investigated by UV/vis spectroscopy. Large Stokes shifts in the neutral and protonated form were observed. The electrochemical oxidation of two typical compounds was studied, however, these oxidations were irreversible forming a polymeric film at the anode. As a selected example, a thiophene‐bridged 2,6‐di(2‐thienyl)pyridine derivative was also investigated by scanning tunneling microscopy showing an interesting self‐assembly into a highly ordered monolayer on highly oriented pyrolytic graphite.

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Broadband efficient light absorbing in the visible regime by a metananoring array
Authors: Cao Shuiyan , Yu Weixing , Zhang Lingtong , Wang Cheng , Zhang Xuming , Fu Yongqi
Published: November 2013

The broadband efficient light‐absorbing property of a metamaterial‐based subwavelength nanoring array in visible regime is reported. The nanoring array can absorb light efficiently with an average absorptivity of 0.97 over the whole visible waveband. In addition, it is found that this kind of super light‐absorbing capability is independent of the incoming light polarization state and can maintain an average of 0.9 for an incident angle as large as ±60° under TM illumination. The perfect absorbing property of the metamaterial‐based nanoring array is attributed to the synergetic effect of the Fabry–Perot resonance and the localized surface plasmon resonance enhancement.
Ultra‐microstructural features of perborate oxidized starch
Authors: Hebeish A. , El‐Rafie M. H. , Rabie A. M. , El‐Sheikh M. A. , El‐Naggar Mehrez E.
Published: November 2013

Ultrafine structures of low, medium, and highly oxidized starches, symbolized as LOS, MOS, and HOS, respectively, were thoroughly investigated. These oxidized starches were obtained by treatment of native starch (NS) with three different concentrations of sodium perborate (SPB). Thus, obtained products were studied with respect to major chemical and fine physical characteristics vis‐a‐vis these of NS (a) acidic and reduced groups creation along with mode of association, (b) significant increase in solubility, and (c) outstanding decrease in apparent viscosity. Thermogravimetric analysis (TGA) revealed thermal stability of the said substrates follows order: HOS > MOS > LOS > NS. Scanning electron micrographs (SEM) showed polygonal or irregular shape with particle size ranging from 2 to 20 μ. After oxidation, the starch surface became rough and the edges lost their definiteness completely. In conclusion, SPB is an efficient oxidant to produce oxidized starches with useful characteristics, which advocate them to wide applications in textile sizing and medicinal domains. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40170.
Antifungal activity of biogenic tellurium nanoparticles against Candida albicans and its effects on squalene monooxygenase gene expression
Authors: Zare Bijan , Sepehrizadeh Zargham , Faramarzi Mohammad Ali , Soltany‐Rezaee‐Rad Mohammad , Rezaie Sassan , Shahverdi Ahmad Reza
Published: November 2013

In this study, we evaluated the antifungal activity of biogenic tellurium nanoparticles (Te NPs) against Candida albicans (ATCC14053). In addition, the effect of these biogenic NPs on squalene monooxygenase activity and the squalene monooxygenase gene (ERG1) expression level was evaluated. Squalene monooxygenase is an important enzyme involved in the synthesis of ergosterol, cholesterol, and phytosterols. Because of the importance of the noted compound, the squalene monooxygenase gene could be considered a good antifungal target. Results showed that biogenic Te NPs had antifungal effect against C. albicans. The minimal fungicidal concentration–minimal inhibitory concentration ratios of the biogenic Te NPs revealed that these NPs exhibited fungicidal effects against the test strain. The results of an enzyme assay using quantitative high‐performance liquid chromatography showed squalene accumulation in C. albicans cells because of enzyme inhibition. Real‐time PCR analysis showed an increase in the expression of the ERG1 gene in C. albicans cells, which were treated with Te NPs (0.2 mg/mL). It is conclution that Te NPs can inhibit the squalene monooxygenase enzyme, and, as a result, this inhibition phenomenon can cause an increase in the expression level of the ERG1 gene. This is the first report of the anti‐Candida effect of biogenic Te NPs and its possible mechanisms.
Cellular responses to individual amino‐acid depletion in antibody‐expressing and parental CHO cell lines
Authors: Fomina‐Yadlin Dina , Gosink John J. , McCoy Rebecca , Follstad Brian , Morris Arvia , Russell Chris B. , McGrew Jeffrey T.
Published: November 2013

Depletion of two nonessential amino acids, asparagine (Asn) and glutamine (Gln), occurred during a fed‐batch production process with a CHO cell line expressing a recombinant antibody. This depletion coincided with growth suppression and the onset of the stationary phase. Experimental withdrawal of Asn led to cell cycle arrest of cell line A in G0/G1 phase. On a mechanistic level, withdrawal of either Asn or Gln stimulated the amino‐acid response (AAR) pathway, indicating that depletion of nonessential amino acids can induce AAR in this cell line. Compared to withdrawal of an essential amino acid, leucine (Leu), withdrawal of either Asn or Gln induced fewer changes in downstream effectors of mammalian target of rapamycin (mTOR) signaling involved in regulation of global protein synthesis. Global transcriptional analysis followed by pathway analysis revealed that the cultures experienced a down‐regulation of cell‐cycle progression, DNA replication and nucleotide biosynthesis in an E2F‐dependent manner, as well as a down‐regulation of lipid metabolism in a SREBP1/2‐dependent manner as a result of individual amino‐acid withdrawal. Timing and magnitude of observed phenotypic and transcriptional responses to amino‐acid withdrawal differed between essential (Leu) and nonessential (Asn and Gln) amino acids examined. Observed responses were similar in parental (CS9 and CHOK‐1) and two other antibody‐producing CHO cell lines, but the magnitude of the transcriptional response was both cell‐line and amino‐acid dependent. Overall, these results suggest that depletion of nonessential amino acids in cell culture plays a role in the onset of the stationary phase of production process and offer mechanistic insights into the observed growth attenuation phenotype. Biotechnol. Biotechnol. Bioeng. 2014;111: 965–979. © 2013 Wiley Periodicals, Inc.
Study on ignition delay of multi‐component syngas using shock tube
Authors: Thi Luong Dinh , Zhang Yingjia , Fu Jin , Huang Zuohua , Zhang Yang
Published: November 2013

Ignition delays of four typical syngas mixtures were investigated using both experimental and simulated methods. The shock tube experiments were conducted behind the reflected shock waves at temperature ranges from 870 to 1 350 K, pressures of 0.2, 1.0 and 2.0 MPa. Six available kinetic models were evaluated by comparing them to the new ignition delay data obtained. NUIG C3 model was in good agreement with the experimental results. The effect of the pressure on ignition delay of all four syngas mixtures was similar to that of hydrogen. The promoting and inhibiting ignition were experimentally observed at high and moderate temperatures, respectively. Sensitivity analyses were conducted at different temperatures and pressures to identify the dominant elementary reactions in the ignition process of the syngas. The results indicated that the ignition delay was generally most sensitive to the chain branching reaction H + O2 = O + OH at both high and low temperatures. Decomposition reaction H2O (+M) = H + OH (+M) was of importance for the syngas with relative inert gas CO2 and N2 at a high temperature. The reaction CO + OH = CO2 + H involving CO kinetic dominated the ignition at a high temperature for the syngas with a high CO level. The inhibiting effect of pressure was attributed to the decrease of sensitivity of the reactions H + O2 = O + OH and O + H2 = H + OH and the increase of sensitivity of the reaction H + O2 (+M) = HO2 (+M) at a moderate‐low temperature.
Impact of Clinical Predictors and Routine Coronary Artery Disease Testing on Outcome of Patients Admitted to Chest Pain Decision Unit
Authors: Cotarlan Vlad , Ho David , Pineda John , Qureshi Anwer , Shirani Jamshid
Published: November 2013

Background

Chest pain decision unit (CDU) evaluation of patients with acute chest pain (ACP) and nondiagnostic electrocardiogram (ECG) usually includes noninvasive testing for coronary artery disease (CAD).

Hypothesis

CAD evaluation will not improve clinical outcome in low‐risk ACP patients.

Methods

We studied 459 adults admitted to CDU with ACP and no troponin release who underwent noninvasive CAD testing (stress testing in 396 and coronary computed tomographic angiography in 63). Multivariate logistic regression was used to determine predictors of adverse outcome over a 3‐year follow‐up period.

Results

Initial noninvasive test was normal in 367 (80%) and abnormal (positive or indeterminate) in 92 (20%). A total of 42 (9%) patients underwent invasive coronary angiography, and 16 (3.5%) underwent revascularization. During follow‐up, 33 patients had a total of 36 major clinical events: 12 revascularizations, 9 myocardial infarctions, and 15 deaths. Multivariate logistic regression analysis identified abnormal ECG (odds ratio [OR]: 2.7, P = 0.03), typical chest pain (OR: 3.8, P = 0.002), diabetes (OR: 4.1, P = 0.001), and known CAD (OR: 2.3, P = 0.03) as independent predictors for adverse outcome, but not noninvasive test result. Thus, in 187 patients with no high‐risk features (41% of the cohort), the annualized event rate was 0.5%. In 272 patients with at least 1 high‐risk feature, annualized event rates were 2.8% and 5.7% when noninvasive test was normal or abnormal, respectively (P = 0.04).

Conclusions

Clinical risk stratification allows identification of patients at low risk of adverse outcome over an intermediate period of follow‐up. Noninvasive testing is not warranted in such patients.
Adding trees to irrigated turfgrass lawns may be a water‐saving measure in semi‐arid environments
Authors: Litvak Elizaveta , Bijoor Neeta S. , Pataki Diane E.
Published: November 2013

Evapotranspiration (ET) of irrigated urban plants is a large yet uncertain component of urban water budgets in semi‐arid regions. A detailed understanding of plot‐scale ET and its sensitivity to plant species composition is necessary to improve estimates of urban water vapour fluxes and water balance. We used portable enclosed chambers and empirical equations to quantify ET from (1) unshaded urban lawns covered exclusively by turfgrass and (2) urban lawns comprised of open‐grown trees and turfgrass groundcover in the Los Angeles Metropolitan area. Turfgrass at all locations had a non‐limiting supply of soil water because of regular sprinkler irrigation. ET of irrigated turfgrass reached a maximum of 10. 4 ± 1·3 mm d−1and was always higher than plot‐scale tree transpiration, which did not exceed 1 mm d−1. In summer, total plot ET of the lawns with trees was lower than lawns without trees by 0·9–3·9 mm d−1. Turfgrass ET was highly sensitive to solar radiation, and the ratio of ET of lawns with trees to ET of lawns without trees decreased with tree canopy cover. Hence, reductions in turfgrass ET caused by shading effects of open‐grown trees were more important in influencing total landscape ET than the addition of tree transpiration. This suggests that low‐density planting of trees that partially shade irrigated urban lawns may be a water‐saving measure in semi‐arid irrigated environments. Copyright © 2013 John Wiley & Sons, Ltd.
Specific and Reversible Alkynyl Transfer Reactions of an N‐Heterocyclic Phosphane
Authors: Gediga Michael , Burck Sebastian , Bender Johannes , Förster Daniela , Nieger Martin , Gudat Dietrich
Published: November 2013

Reaction of P‐chloro‐1,3,2‐diazaphospholenes with alkynyllithium or Grignard reagents produced N‐heterocyclic alkynylphosphanes 3a–c. Terminal alkynylphosphane 3c reacted in the presence of a catalytic amount of CuCl with formation of bis‐phosphanylalkyne 4, ethyne and chlorodiazaphospholene 2b, which was converted into the appropriate azide 6 upon addition of LiN3. Detailed studies allowed us to explain the formal alkynyl/Cl metathesis and alkynyl scrambling as arising from a combination of Cu‐catalysed cross‐coupling steps and the reverse processes, which involved Cu‐induced P–C bond breaking. The superposition of individual steps allows the formulation of an equilibrium reaction: 2 3c [lrarr2] 4 + HCCH. Shift of the equilibrium by enforced release of acetylene into the gas phase enabled quantitative conversion of 3c into 4. Traces of P–C bond‐activation products were also detected upon action of CuCl on 3b with an internal triple bond, but alkynylphosphanes with Ph2P or (iPr2N)2P moieties were unreactive. Alkynylphosphanes 3a–c and 4 were characterised by spectroscopic data and single‐crystal X‐ray diffraction studies. The presence of notably elongated P–C bonds points to a bond‐weakening effect, which is responsible for explaining the unusual P–C bond reactivity.
An Approach to the Carbon Backbone of Bielschowskysin, Part 2: Non‐Photochemical Strategy
Authors: Farcet Jean‐Baptiste , Himmelbauer Martin , Mulzer Johann
Published: November 2013

The stereocontrolled synthesis of complex and highly substituted polycyclic synthetic precursor 2 of the diterpene bielschowskysin is presented. Key steps include a regio‐ and stereoselective hydroalumination as well as an optimized Cr/Ni‐mediated carbon–carbon bond formation between two complex fragments to establish the northern hemisphere of the natural product.
Generation and Conjugate Additions of o‐Quinone Methides Under Mild Base Conditions: Rapid Synthesis of N‐Substituted Aryl Glycine Derivatives
Authors: Wang Wei , Zheng Zhong , Wang Xiangmin , Chen Jinchun
Published: November 2013

A one‐step approach was observed to give N‐substituted aryl glycine derivatives in good to excellent yields (up to 93 %) from (ortho‐hydroxymethyl)aryl benzoates. A cascade mechanism was proposed for the generation and in situ conjugate addition of the ortho‐quinone methides. This mechanism is strongly supported by our subsequent findings that tertiary amines could promote the process. Different functional groups on the (ortho‐hydroxymethyl)aryl benzoates and various amines were investigated to explore the scope of this cascade process. The substituents on the substrates strongly affected the reaction time and yield, and various primary and secondary amines were used as nucleophiles. The addition of tertiary amines enhanced the addition process for less basic nucleophiles.
A Defunctionalization Concept for the Convenient Synthesis of Bis(5‐arylfuran‐2‐yl)methane Scaffolds
Authors: Tiwari Praveen Kumar , Mukhopadhyay Tufan , Aidhen Indrapal Singh
Published: November 2013

The bis(5‐arylfuran‐2‐yl)methane framework has been obtained through defunctionalization of aryl ketones, derived from abundantly available L‐(+)‐tartaric acid, under the influence of acid. The stereocomponents present in these starting aryl ketones have been found to be insignificant for this transformation.
Tunable Phosphine‐Triggered Cascade Reactions of MBH Derivatives and 3‐Acyl‐2H‐chromen‐2‐ones: Highly Selective Synthesis of Diverse Chromenones
Authors: Yuan Wei , Zheng Hu‐Fei , Yu Zhi‐Hua , Tang Zi‐Long , Shi De‐Qing
Published: November 2013

Diverse chromenones were synthesized through tunable phosphine‐mediated cascade reactions between 3‐acyl‐2H‐chromen‐2‐ones and Morita–Baylis–Hillman (MBH) derivatives. With different phosphine loadings and reaction temperatures, MBH derivatives act either as C1 or C3 synthons for the construction of potential biologically active 3‐dihydrofuran‐fused chromen‐2‐ones, 4‐allyl‐3‐acyl‐chromen‐2‐ones, or 6H‐benzo[c]chromen‐6‐ones. This method has the advantages of mild conditions, simple workup, and wide substrate scope, which make it powerful for the synthesis of diverse chromenone derivatives.
The Synthesis of Tetrazoles in Nanometer Aqueous Micelles at Room Temperature
Authors: Xie Aming , Cao Meiping , Liu Yangyang , Feng Liandong , Hu Xinyu , Dong Wei
Published: November 2013

A newly developed nonionic amphiphile (GPGS‐1500), a diester composed of a Guerbet alcohol (2‐octyldodecan‐1‐ol), poly(ethylene glycol) 1500 (PEG 1500), and succinic acid esters, has been prepared as an effective nanomicelle‐forming species for the synthesis of tetrazoles in water at room temperature.
Aldosterone stimulates Na,K‐ATPase activity in basolateral membrane of rat kidney
Authors: Seok Jeong‐Ho , Kim Ju‐Byoung , Hong Jang‐Hee , Hur Gang‐Min , Jeon Jong‐Rye , Lim Kyu , Hwang Byung‐Doo , Lee Jae‐Heun
Published: November 2013

The changes of Na,K‐ATPase activity and its regulation have been investigated in the renal cortex and its basolateral membrane of aldosterone‐induced hypertensive rat. Ouabain‐sensitive Na,K‐ATPase activity and [3H]ouabain‐binding site (Bmax) in the hypertensive rat were significantly increased than those in the control. The levels of Na,K‐ATPase α1‐ and β1‐subunit mRNA of the renal cortex in hypertensive rat were more increased than those in the control, and their increases were repressed by actinomycin‐D. These results suggest that the increase of Na,K‐ATPase activities and ouabain binding sites in aldosterone‐induced hypertensive rat may be correlated with transcriptional regulation of Na,K‐ATPase gene expression.
Purification and cell attachment activity of a D‐galactose‐binding lectin from the skin of sea hare, Aplysia Kurodai
Authors: Ozeki Yasuhiro
Published: November 2013

A D‐galactose‐binding lectin which does not require Ca2+ or reducing reagents to induce activity was purified from skin of sea hare, Aplysia kurodai, by affinity chromatography. Skin lectin was confirmed to be a disulfide‐bonded heteromultimer with molecular mass of 200 kDa, consisting of 28 kDa and 26 kDa subunits by SDS‐PAGE and two‐dimensional SDS‐PAGE. Human rhabdomyosarcoma cells attached to and spread on plastic plates coated with lectin. Cell adhesion induced by lectin was completely inhibited by the addition of lactose.
Biochemical characterization of the third domain From Bacillus thuringiensis CRY1A Toxins
Authors: Vázquez‐Padrón Robert I. , Martínez‐Gil Ariel F. , Ayra‐Pardo Camilo , González‐Cabrera Joel , Prieto‐Samsonov Dmitri L. , de la Riva Gustavo A.
Published: November 2013

Cry proteins from Bacillus thuringiensis have insecticidal properties. The function of domains I and II has been described but domain III has so far eluded understanding. Domain III from Cry1Ab and Cry1Ac has been cloned, expressed in E. coli and injected to rabbits with the aid of characterizing them immunologically. Interestingly, polyclonal antibodies against Cry1Ab fragment did not recognize either the native Cry1Ab toxin or the Cry1Ac fragment while those against the latter did recognize either the native Cry1Ac toxin or the Cry1Ab protein fragment. A combination of information from sequence comparison and hydrophobicity profile indicates that these protein fragments possibly adopt different spatial dispositions within the respective toxins.
A survey of the parallel performance and accuracy of Poisson solvers for electronic structure calculations
Authors: García‐Risueño Pablo , Alberdi‐Rodriguez Joseba , Oliveira Micael J. T. , Andrade Xavier , Pippig Michael , Muguerza Javier , Arruabarrena Agustin , Rubio Angel
Published: November 2013

We present an analysis of different methods to calculate the classical electrostatic Hartree potential created by charge distributions. Our goal is to provide the reader with an estimation on the performance—in terms of both numerical complexity and accuracy—of popular Poisson solvers, and to give an intuitive idea on the way these solvers operate. Highly parallelizable routines have been implemented in a first‐principle simulation code (Octopus) to be used in our tests, so that reliable conclusions about the capability of methods to tackle large systems in cluster computing can be obtained from our work. © 2013 Wiley Periodicals, Inc.
The role of domain shuffling in the evolution of signaling networks
Authors: Di Roberto Raphael B. , Peisajovich Sergio G.
Published: November 2013

In a seminal paper entitled “Evolution and Tinkering,” François Jacob affirmed that: “Novelties come from previously unseen association of old material. To create is to recombine” [Jacob F. (1977) Science 196:1161–1166]. In the 35 years that have passed since Jacob's insight, we have amassed enough data to actually shed light on many of the molecular mechanisms that enable evolution to create novelty by simply recombining what existed already. In this review, we will succinctly discuss the role that the recombination of protein domains has in the evolution of signaling networks, drawing from examples provided by diverse disciplines, including bioinformatics, systems and synthetic biology, and laboratory evolution. J. Exp. Zool. (Mol. Dev. Evol.) 322B: 65–72, 2014. © 2013 Wiley Periodicals, Inc.
Novel 2,4,5‐Trisubstituted Pyridines as Key Intermediates for the Preparation of the TSPO Ligand 6‐F‐PBR28: Synthesis and Full 1H and 13C NMR Characterization
Authors: Damont Annelaure , Lemée Frédéric , Raggiri Guillaume , Dollé Frédéric
Published: November 2013

As part of our ongoing research for molecular structures binding to the translocator protein (TSPO 18 kDa), we investigated the preparation of a number of new 2,4,5‐trisubstituted pyridines as novel building blocks. In particular, 5‐amino‐2‐halo‐4‐phenoxypyridines (11, 12, 13) were designed as key intermediates for the synthesis of the recently developed TSPO ligand 6‐F‐PBR28 and its fluorine‐18‐labeled version for positron emission tomography, 6‐[18F]F‐PBR28. We hereby report the chemical preparation as well as the 1H and 13C NMR spectroscopic data of polysubstituted pyridines 2, 3, 4, 5, 6, 7, 7b, 8, 9, 10, 11, 12, 13, 14. The latter demonstrates dramatic changes in electron density repartition of the aromatic ring upon substitution.
An academic hospitalist model to improve healthcare worker communication and learner education: Results from a quasi‐experimental study at a veterans affairs medical center
Authors: Saint Sanjay , Fowler Karen E. , Krein Sarah L. , Flanders Scott A. , Bodnar Timothy W. , Young Eric , Moseley Richard H.
Published: November 2013

BACKGROUND

Although hospitalists may improve efficiency and quality of inpatient care, their effect on healthcare‐worker communication and education has been less well‐studied.

OBJECTIVE

To test various approaches to improving healthcare‐worker communication and learner education within the context of a newly designed academic hospital medicine program.

DESIGN

Before‐and‐after design with concurrent control group.

SETTING

A Midwestern Veterans Affairs medical center.

INTERVENTION

Multimodal systems redesign of 1 of 4 medical teams (Gold team) that included clinical modifications (change in rounding structure, with inclusion of nurses, a Clinical Care Coordinator, and a pharmacist) and educational interventions (providing explicit expectations of learners and providing a reading list for both learners and attending physicians).

MEASUREMENTS

Number of admissions, length of stay, readmissions, house officer and medical student ratings of attendings' teaching, medical student internal medicine National Board of Medical Examiners Subject Examination (“shelf” exam) scores, and clinical staff surveys.

RESULTS

Length of stay was reduced by about 0.3 days on all teams after the initiative began (P = 0.004), with no significant differences between Gold and non‐Gold teams. The majority of physicians (83%) and nurses (68%) felt that including nurses during rounds improved healthcare‐worker communication; significantly more nurses were satisfied with communication with the Gold team than with the other teams (71% vs 53%; P = 0.02). Gold attendings generally received higher teaching scores compared with non‐Gold attendings, and third‐year medical students on the Gold team scored significantly higher on the shelf exam compared with non–Gold team students (84 vs 82; P = 0.006).

CONCLUSIONS

Academic hospitalists working within a systems redesign intervention were able to improve healthcare‐worker communication and enhance learner education without increasing patient length of stay or readmission rates. Journal of Hospital Medicine 2013;8:702–710. 2013 The Authors. Journal of Hospital Medicine published by Wiley Periodicals, Inc. on behalf of Society of Hospital Medicine
ESTIMATING THE IMPACT OF A FINANCIAL CRISIS—COMBINING RAPID QUALITATIVE STUDIES WITH NATIONALLY REPRESENTATIVE SURVEYS
Authors: McCulloch Neil , Grover Amit
Published: November 2013

This paper tests the conclusions of a qualitative study on the impact of the financial crisis on the labour market in Indonesia using evidence from nationally representative labour force surveys from before and after the onset of the crisis. We find that Indonesia weathered the storm rather well: there is no evidence for increased school dropout; labour force participation fell, particularly for young workers, whilst unemployment rose for the young, but fell for workers over 25 years old. Surprisingly, real wages for employees rose during the crisis period, although those in the informal sector did not benefit to the same extent. Copyright © 2013 John Wiley & Sons, Ltd.
IMPACT OF THE GLOBAL FINANCIAL AND ECONOMIC CRISIS ON DEVELOPMENT: WHITHER AFRICA?
Authors: Fosu Augustin Kwasi
Published: November 2013

The global economic crisis beginning in 2008 has come at an inopportune time for Africa. Economic growth had recovered, poverty had declined, and human development had improved. Then the crisis hit. Growth then fell by 60 per cent. The growth decline has been less than in previous economic crises though. Africa's resilience currently likely results from improvements in economic and political governance and to changes in the external environment. It appears that Africa will once again resume its path towards prosperity. However, although low‐income and ‘fragile’ countries appear to be holding up well, many of them critically depend on external assistance. Above all, the commitment to improved governance must continue. Copyright © 2013 John Wiley & Sons, Ltd.
C‐H…O hydrogen bonds in FK506‐binding protein–ligand interactions
Authors: Rajan Sreekanth , Baek Kwanghee , Yoon Ho Sup
Published: November 2013

Hydrogen bonds are important interaction forces observed in protein structures. They can be classified as stronger or weaker depending on their energy, thereby reflecting on the type of donor. The contribution of weak hydrogen bonds is deemed as an important factor toward structure stability along with the stronger bonds. One such bond, the C‐H…O type hydrogen bond, is shown to make a contribution in maintaining three dimensional structures of proteins. Apart from their presence within protein structures, the role of these bonds in protein–ligand interactions is also noteworthy. In this study, we present a statistical analysis on the presence of C‐H…O hydrogen bonds observed between FKBPs and their cognate ligands. The FK506‐binding proteins (FKBPs) carry peptidyl cis–trans isomerase activity apart from the immunosuppressive property by binding to the immunosuppressive drugs FK506 or rapamycin. Because the active site of FKBPs is lined up by many hydrophobic residues, we speculated that the prevalence of C‐H…O hydrogen bonds will be considerable. In a total of 25 structures analyzed, a higher frequency of C‐H…O hydrogen bonds is observed in comparison with the stronger hydrogen bonds. These C‐H…O hydrogen bonds are dominated by a highly conserved donor, the Cα/β of Val55 and an acceptor, the backbone oxygen of Glu54. Both these residues are positioned in the β4‐α1 loop, whereas the other residues Tyr26, Phe36 and Phe99 with higher frequencies are lined up at the opposite face of the active site. These preferences could be implicated in FKBP pharmacophore models toward enhancing the ligand affinity. This study could be a prelude to studying other proteins with hydrophobic pockets to gain better insights into ligand recognition. Copyright © 2013 John Wiley & Sons, Ltd.
Molecular recognition of a model globular protein apomyoglobin by synthetic receptor cyclodextrin: effect of fluorescence modification of the protein and cavity size of the receptor in the interaction
Authors: Saha Ranajay , Rakshit Surajit , Pal Samir Kumar
Published: November 2013

Labelling of proteins with some extrinsic probe is unavoidable in molecular biology research. Particularly, spectroscopic studies in the optical region require fluorescence modification of native proteins by attaching polycyclic aromatic fluoroprobe with the proteins under investigation. Our present study aims to address the consequence of the attachment of a fluoroprobe at the protein surface in the molecular recognition of the protein by selectively small model receptor. A spectroscopic study involving apomyoglobin (Apo‐Mb) and cyclodextrin (CyD) of various cavity sizes as model globular protein and synthetic receptors, respectively, using steady‐state and picosecond‐resolved techniques, is detailed here. A study involving Förster resonance energy transfer, between intrinsic amino acid tryptophan (donor) and N, N‐dimethyl naphthalene moiety of the extrinsic dansyl probes at the surface of Apo‐Mb, precisely monitor changes in donor acceptor distance as a consequence of interaction of the protein with CyD having different cavity sizes (β and γ variety). Molecular modelling studies on the interaction of tryptophan and dansyl probe with β‐CyD is reported here and found to be consistent with the experimental observations. In order to investigate structural aspects of the interacting protein, we have used circular dichroism spectroscopy. Temperature‐dependent circular dichroism studies explore the change in the secondary structure of Apo‐Mb in association with CyD, before and after fluorescence modification of the protein. Overall, the study well exemplifies approaches to protein recognition by CyD as a synthetic receptor and offers a cautionary note on the use of hydrophobic fluorescent labels for proteins in biochemical studies involving recognition of molecules. Copyright © 2013 John Wiley & Sons, Ltd.
Molecularly imprinted cryogels for human interferon‐alpha purification from human gingival fibroblast culture
Authors: Ertürk Gizem , Bereli Nilay , Tümer M. Aşkın , Say Rıdvan , Denizli Adil
Published: November 2013

Interferons are important proteins for the immune system because of their antiviral, anti‐proliferating and immunomodulatory activities. Therapeutic value of these proteins against certain types of tumors caused interest and investigations aimed to obtain highly purified interferons. Molecular imprinting is an efficient method for purification with high selectivity, specificity and good reproducibility. In this study, we utilized advantages of molecular imprinting technique for the purification of interferon from human gingival fibroblast culture. For this purpose, interferon α‐2b imprinted poly(hydroxyethyl methacrylate) cryogel (hIFN‐α‐MIP) was prepared. Optimum adsorption conditions were determined, and maximum adsorption capacity of hIFN‐α‐MIP cryogel was found as 254.8 × 104 IU/g from aqueous solution. All interferon measurements are expressed as International Unit (IU), which is a unit measurement used to quantify biologically active substances like interferon based on their biological activity or effect. Selectivity experiments were performed using competitive proteins and repeated adsorption–desorption studies showed that the adsorption capacity maintained almost at a constant value after ten cycles. For the purification of interferon from human gingival fibroblast culture, fast protein liquid chromatography was used and the specific activity of the purified interferon α‐2b on HeLa cell line was found between the values 3.45 × 108 IU/mg and 3.75 × 108 IU/mg. The results are promising, and the molecular imprinting technique is effective for the purification of interferon α‐2b. Copyright © 2013 John Wiley & Sons, Ltd.
Cellular interplay among Th17, Th1, and Treg cells in HIV‐1 subtype “C” infection
Authors: Singh Alpana , Vajpayee Madhu , Ali Sharique A. , Chauhan Neeraj Kumar
Published: November 2013

CD4 T cell depletion is central to HIV pathogenesis and disease progression. Different subsets of CD4 T cells cooperate to combat an infection. Therefore, the immune balance among Th17, Th1, and Treg cells may be critical in HIV immunopathogenesis which is not adequately defined yet. The impact of HIV‐1 infection on the interplay of Th17/Th1/Treg cells in HIV‐1 infected Indian individuals was examined in the present study and report that HIV‐1 Gag specific peripheral blood Th17 cells were significantly depleted in late infected subjects, compared to early infected subjects and slow progressors. Although, the gradual loss of Th1 cells was also reported during HIV‐1 disease progression but relative to Th17 cells, Th1 cells were found to be more resistant to HIV‐1 infection. Additionally, a significant and progressive gain in Treg cellular frequency was observed as disease progress from early to late stage of HIV‐1 infection. This study also indicate that slow progressors might have an intrinsic capacity to develop strong HIV‐1 specific Th17 and Th1 cell responses contrasted with a faint Treg cellular performance signifies the importance of these cellular subsets in progressive versus nonprogressive HIV‐1 infection. A significant gradual loss of Th17/Treg ratio was found to be associated with disease state, plasma viral load and immune activation. J. Med. Virol. 86:372–384, 2014. © 2013 Wiley Periodicals, Inc.
Infection of human islets of langerhans with two strains of coxsackie B virus serotype 1: Assessment of virus replication, degree of cell death and induction of genes involved in the innate immunity pathway
Authors: Anagandula Mahesh , Richardson Sarah J. , Oberste M. Steven , Sioofy‐Khojine Amir‐Babak , Hyöty Heikki , Morgan Noel G. , Korsgren Olle , Frisk Gun
Published: November 2013

Type 1 diabetes mellitus is believed to be triggered, in part, by one or more environmental factors and human enteroviruses (HEVs) are among the candidates. Therefore, this study has examined whether two strains of HEV may differentially affect the induction of genes involved in pathways leading to the synthesis of islet hormones, chemokines and cytokines in isolated, highly purified, human islets. Isolated, purified human pancreatic islets were infected with strains of Coxsackievirus B1.Viral replication and the degree of CPE/islet dissociation were monitored. The expression of insulin, glucagon, CXCL10, TLR3, IF1H1, CCL5, OAS‐1, IFNβ, and DDX58 was analyzed. Both strains replicated in islets but only one of strain caused rapid islet dissociation/CPE. Expression of the insulin gene was reduced during infection of islets with either viral strain but the gene encoding glucagon was unaffected. All genes analyzed which are involved in viral sensing and the development of innate immunity were induced by Coxsackie B viruses, with the notable exception of TLR3. There was no qualitative difference in the expression pattern between each strain but the magnitude of the response varied between donors. The lack of virus induced expression of TLR3, together with the differential regulation of IF1H1, OAS1 and IFNβ, (each of which has polymorphic variants influence the predisposition to type 1 diabetes), that might result in defective clearance of virus from islet cells. The reduced expression of the insulin gene and the unaffected expression of the gene encoding glucagon by Coxsackie B1 infection is consistent with the preferential β‐cell tropism of the virus. J. Med. Virol. 86:1402–1411, 2014. © 2013 Wiley Periodicals, Inc.
GBV‐C viremia and clinical events in advanced HIV infection
Authors: Sahni Harleen , Kirkwood Katherine , Kyriakides Tassos C. , Stapleton Jack , Brown Sheldon T. , Holodniy Mark ,   for OPTIMA Study Team
Published: November 2013

GB Virus C (GBV‐C) is a non‐pathogenic flavivirus, commonly found in HIV infected patients. Studies suggest a survival benefit of GBV‐C viremia in HIV infection. Impact of GBV‐C viremia was evaluated on clinical outcome in multidrug‐resistant HIV. The OPTIMA study enrolled advanced multidrug‐resistant HIV patients with a CD4 count ≤300 cells/mm3. This study included a subset of OPTIMA patients. Primary endpoints included AIDS events or death. GBV‐C status was assessed at baseline and last time point on study by real‐time PCR. Cox proportional hazards models were used to determine if CD4 count (</>100/mm3), treatment assignment, presence or disappearance of GBV‐C viremia, GBV‐C viral load level and Hepatitis C virus antibody status were associated with outcome. Of 288 patients (98% male, baseline mean age 48 years, HIV viral load 4.67 log10/ml, and CD4 127 cells/mm3), 62 (21.5%) had detectable GBV‐C viremia. The mortality rate for GBV‐C infected subjects was lower, 19/62 (30.7%) versus 87/226 (38.5%), and time to death shorter (HR 0.67, 95% CI 0.41–1.11), but the results were not significantly different. The time to development of AIDS events was not different (HR 0.90, 95% CI 0.52–1.53). Among covariates, only CD4 count (HR 0.28, CI 0.19–0.42) had a significant survival effect. A trend in decreased mortality was seen in GBV‐C+ patients with CD4 <100/mm3 in multivariate analyses. GBV‐C co‐infection in multidrug‐resistant HIV infected patients was associated with a trend in improved survival but not decreased AIDS events. Analysis was limited by cohort size. J. Med. Virol. 86:426–432, 2014. © 2013 Wiley Periodicals, Inc.
Attenuation of β‐amyloid‐induced tauopathy via activation of CK2α/SIRT1: Targeting for cilostazol
Authors: Lee Hye Rin , Shin Hwa Kyoung , Park So Youn , Kim Hye Young , Lee Won Suk , Rhim Byung Yong , Hong Ki Whan , Kim Chi Dae
Published: November 2013

β‐Amyloid (Aβ) deposits and hyperphosphorylated tau aggregates are the chief hallmarks in the Alzheimer's disease (AD) brains, but the strategies for controlling these pathological events remain elusive. We hypothesized that CK2‐coupled SIRT1 activation stimulated by cilostazol suppresses tau acetylation (Ac‐tau) and tau phosphorylation (P‐tau) by inhibiting activation of P300 and GSK3β. Aβ was endogenously overproduced in N2a cells expressing human APP Swedish mutation (N2aSwe) by exposure to medium containing 1% fetal bovine serum for 24 hr. Increased Aβ accumulation was accompanied by increased Ac‐tau and P‐tau levels. Concomitantly, these cells showed increased P300 and GSK3β P‐Tyr216 expression; their expressions were significantly reduced by treatment with cilostazol (3–30 μM) and resveratrol (20 μM). Moreover, decreased expression of SIRT1 and its activity by Aβ were significantly reversed by cilostazol as by resveratrol. In addition, cilostazol strongly stimulated CK2α phosphorylation and its activity, and then stimulated SIRT1 phosphorylation. These effects were confirmed by using the pharmacological inhibitors KT5720 (1 μM, PKA inhibitor), TBCA (20 μM, inhibitor of CK2), and sirtinol (20 μM, SIRT1 inhibitor) as well as by SIRT1 gene silencing and overexpression techniques. In conclusion, increased cAMP‐dependent protein kinase‐linked CK2/SIRT1 expression by cilostazol can be a therapeutic strategy to suppress the tau‐related neurodegeneration in the AD brain. © 2013 Wiley Periodicals, Inc.
Fostering Entrepreneurship in China: A Survey of the Economic Literature
Authors: Milana Carlo , Wang Jinmin
Published: November 2013

The economic literature can help us find how to foster entrepreneurship in China in order to ensure a sustainable economic growth.

Someone asked Confucius ‘Why do you not take part in government?’ The Master replied: ‘The Book of History says, Oh! Simply by being a good son and friendly to his brothers, a man can exert an influence upon government.” In so doing a man is, in fact, taking part in government.’

(Confucius, The Anaclets, II.21. Translated by D.C. Lau, 1979)

Zeal without knowledge is the sister of folly.

(John Davies of Hereford, The Scourge of Folly, 1611)
Does Demutualization Enhance Financial Performance of Stock Exchanges in Developing and Emerging Economies?
Authors: Tahir Alyas Qadeer , Sial Abdul Wahid
Published: November 2013

Changes in stock exchange ownership and governance structures lead to better financial performance indicators, except for fixed assets utilization in developing and emerging economies.
Dynamics of Value Creation in Indian Bilateral Cross‐Border Joint Ventures: A Systems Approach
Authors: Dhir Sanjay , Mital Amita , Srivastava Samir K.
Published: November 2013

The proposed approach helps to identify all pertinent factors and causal relationships which influence value creation cross‐border joint ventures (CBJVs).
Entrepreneurship and Small Business in the Republic of Macedonia
Authors: Ramadani Veland
Published: November 2013

Entrepreneurship and small business play an important role in the development of the economy of Macedonia.
Social Innovation in Emerging Economies: A Resource‐Based View Perspective
Authors: Descubes Irena , Timsit Jean‐Philippe , Truong Yann
Published: November 2013

Emerging economies can achieve substantial innovation with limited resources based on the analysis of demand (user needs) in contrast with the traditional RBV theory, which considers supply as the departure point of innovation.