bluuebunny/crossref_metadata_2025 huggingface dataset:
Molecular Modeling Evaluation of Non‐Steroidal Aromatase Inhibitors†
Authors: Narayana Bheemanapalli Lakshmi , Pran Kishore Deb , Balakumar Chadrasekaran , Rao Kaki Venkata , Kaur Rajwinder , Rao Akkinepally Raghuram , Murthy Javali Narashima , Ravikumar Muttineni
Published: December 2011

A recent discovery of aromatase crystal structure triggered the efforts to design novel aromatase inhibitors for breast cancer therapy. While correlating docking scores with inhibitory potencies of known ligands, feeble robustness of scoring functions toward prediction was observed. This prompted us to develop new prediction models using stepwise regression analysis based on consensus of different docking and their scoring methods (gold, LigandFit, and glide). Quantitative structure–activity relationships were developed between the aromatase inhibitory activity (pIC50) of flavonoid derivatives (n = 39) and docking scores and docking descriptors. QSAR models have been validated internally [using leave‐one‐out cross‐validated )] and externally to ensure the predictive capacity of the models. Model 2 [M2] developed using consensus of docking scores of scoring functions viz. ASP, potential of mean force and DOCK Score ( = 0.850, r2 = 0.870,  = 0.633, RMSE = 0.363 μm, r2m(test) = 0.831, r2m(overall) = 0.832) was found to be better in predicting aromatase inhibitory potency (pIC50) compared to the Model 1 [M1] based on docking descriptors ( = 0.848, r2  =  0.825,  = 0.788, RMSE = 0.421 μm, r2m(test) = 0.808, r2m(overall) = 0.821). It has been observed that the natural flavonoids and their derivatives were less potent compared to these scaffolds with imidazolylmethyl substitution owing to the interaction of nitrogen atom of the imidazole ring toward the heme (Fe3+) of the aromatase. Results confirm the potential of our methodology for the design of new potent non‐steroidal aromatase inhibitors.
Synthesis of Aminoquinoline‐Based Aminoalcohols and Oxazolidinones and Their Antiplasmodial Activity
Authors: Kobarfard Farzad , Yardley Vanessa , Little Susan , Daryaee Fereidoon , Chibale Kelly
Published: December 2011

Novel aminoquinoline β‐aminoalcohol and oxazolidinone derivatives were designed, synthesized, and evaluated for in vitro antiplasmodial activity against a chloroquine‐sensitive (3D7) and chloroquine‐resistant (K1) strains of Plasmodium falciparum. A few β‐aminoalcohol derivatives were more potent than chloroquine against chloroquine‐sensetive Plasmodiums. The potency of these derivatives decreased against chloroquine‐resistant species in all cases (higher resistance indices), suggesting a possible cross‐resistance between this group of compounds and chloroquine which could be due to their structural similarity. Although changing β‐aminoalcohols to their oxazolidinone counterparts decreased the potency in all the cases, the compounds were still active and the resistance indices for these compounds improved significantly in comparison with those of β‐aminoalcohols. This may indicate the absence of cross‐resistance between these new derivatives and chloroquine.
From ‘arms, malice, and menacing’ to the courts: disputed elections and the reform of the election petitions system
Authors: Morris Caroline
Published: December 2011

For almost as long as there have been elections, their outcomes have been disputed. Disgruntled candidates have tried many different avenues to right the wrongs of an election they consider they should have won. For several hundred years, jurisdiction over disputed elections was exercised by the Monarch personally, then by the courts, and then by Parliament until finally, in the 1860s, Parliament ceded its power to the courts in the form of the election petitions jurisdiction. This paper considers that history, examines the current system of election petitions, and proposes a number of reforms to this crucial aspect of British democracy.
Primary immunodeficiencies in highly consanguineous North African populations
Authors: Barbouche Mohamed‐Ridha , Galal Nermeen , Ben‐Mustapha Imen , Jeddane Leïla , Mellouli Fethi , Ailal Fatima , Bejaoui Mohamed , Boutros Jeanette , Marsafy Aisha , Bousfiha Ahmed Aziz
Published: December 2011

The study of inbred populations has contributed remarkably to the description of new autosomal recessive primary immunodeficiencies (PIDs). Here, we examine the pattern of PIDs in North African populations and assess the impact of highly prevalent consanguinity. This review reports on the current status of pediatricians’ awareness of PIDs in Egypt, Morocco, and Tunisia, where awareness of PIDs is relatively recent. The phenotypic distribution of PIDs is reported and compared among the three countries and with other populations. Data analysis reveals a prevalence of autosomal recessive forms and a peculiar distribution of major PID categories, particularly more combined immunodeficiencies than antibody disorders. In these endogamous communities, molecular diagnosis is critical to developing a genetic‐based preventive approach. The organization of diagnosis and care services in these resource‐limited settings faces many obstacles. Autosomal recessive PIDs are overrepresented; thus, it is critical to continue investigation of these diseases in order to better understand the underlying mechanisms and to improve patient care.
Photoisomerization of Alfa Calcidol by a Sensitized Quantum Chain Reaction†
Authors: Estruch Gastón A. , Aramendía Pedro F.
Published: December 2011

The production of vitamin D3 is a pharmaceutically relevant process, producing high added‐value products. Precursors are extracts from vegetal origin but bearing mainly an E geometry in the 5,6 double bond. The synthesis of vitamin D3 (5‐E‐α‐calcidol) with the correct Z stereochemistry in the 5,6 double bond from the E isomer using anthracene and triethylamine (TEA) as the sensitizer system was studied from the kinetic and mechanistic point of view. The sensitized isomerization of E‐calcidol by irradiation of anthracene takes place only in deoxygenated solution and yields the Z isomer in ca 5% yield in the photostationary state. When TEA is added to the system, the E–Z reaction is not inhibited by oxygen any more, the quantum yield of photoisomerization to the Z isomer grows linearly with the concentration of E‐calcidol, while conversions higher than 95% to the Z isomer are reached in the photostationary state and E–Z quantum yields as high as 45 at [E‐calcidol] = 25 mm are reached. If TEA is replaced by 1,4‐diazabicyclo[2.2.2]octane, the reaction rate drops to one‐third at the same amine concentration. The observations can be explained by a quantum chain reaction mechanism. The high conversion achieved eliminates the need of isomer separation.
OF TAPYROI AND TABLETS, STATES AND TRIBES: THE HISTORICAL GEOGRAPHY OF PASTORALISM IN THE ACHAEMENID HEARTLAND IN GREEK AND ELAMITE SOURCES
Authors: HENKELMAN WOUTER F. M.
Published: December 2011

The Persian tribe of the Tapyroi appears to be at home in the Caspian region according to the classical sources, except for one passage in Arrian's Anabasis. The Elamite texts from the Persepolis Fortification archive now add more information on this second group of Tapyroi. More important, these sources allow for a new contextualization of classical accounts on the tribes of Achaemenid Iran and yield a more complete image of their status within, and interaction with, the state.
Risk factors for race‐associated sudden death in Thoroughbred racehorses in the UK (2000–2007)
Authors: LYLE C. H. , BLISSITT K. J. , KENNEDY R. N. , MC GORUM B. C. , NEWTON J. R. , PARKIN T. D. H. , STIRK A. , BODEN L. A.
Published: December 2011

Reasons for performing study:Sudden death adversely affects racehorse welfare, jockey safety and the public perception of horseracing.

Objective:To describe the risk of racing‐associated sudden death in Thoroughbred racehorses in the UK from 2000 to 2007, to identify whether there were risk factors uniquely associated with sudden death and to improve the understanding of the pathogenesis of racing‐associated sudden death by identification of risk factors for such cases.

Methods:A sudden death was defined as an acute collapse and death, in an apparently healthy Thoroughbred racehorse, during or immediately after racing, in the absence of clinical data indicative of a catastrophic orthopaedic injury. The retrospective study included 201 case race starts and 705,712 control race starts. Univariable and multivariable logistic regression were used to identify risk factors for sudden death at any one start.

Results:In the multivariable model, age, distance, race type, season and number of starts in the 60 days prior to the race were associated with sudden death.

Conclusions:The risk factors identified in this study are not uniquely associated with sudden death and have been also been identified in studies using all causes of fatality as the outcome. These data suggest that a generic approach to reduce fatal musculoskeletal injury and sudden death may be possible.

Potential relevance:The identification of risk factors allows speculation on the underlying mechanisms of sudden death in racing. This may stimulate hypothesis‐led investigations into the pathogenesis of exercise‐related arrhythmias, exercise‐induced pulmonary haemorrhage and blood vessel rupture.

See also correspondence by Cook
Inner-Loop Control for Electro-Hydraulic Actuation Systems
Authors: El Sayed Mohammed A. , Habibi Saeid
Published: December 2011

This article presents the development of a multiple inner-loop control strategy for improving the performance of hydrostatic actuation systems. In these actuators, the presence of nonlinearities associated with pump/motor static friction and backlash, pressure drop in the piping system, and nonlinear friction at the load have a significant effect on the performance and positional accuracy of the system. The effect of nonlinear friction at the pump/motor interface has been overcome by the use of a high gain pump-speed inner-loop control strategy. In this article, the concept of inner-loop control will be extended to target other specific sources of performance degradation. Velocity feedback will be incorporated in this manner to decrease the effects of pump backlash and nonlinear friction at the load. Simulation results supported by theoretical analysis indicate that a considerable improvement in performance can be achieved by the implementation of this control strategy.
Statistical Evaluation of Local Stress and Strain of Three Dimensional Polycrystalline Material at Elevated Temperature
Authors: Watanabe Osamu
Published: December 2011

The present paper presents results of numerical simulation for statistical evaluation of stress and strain at elevated temperature from view point of crystal plasticity level by employing a new Voronoi tessellation algorithm in the three dimensional geometry for general grain shape using first order tetrahedron element (four nodes). The elasticity tensors are assumed to include isotropic material and anisotropic material of FCC or BCC crystal using three material constant parameters. The employed finite element formulation is based on the updated Lagrange type expressed in the general form using trapezoidal integration rule in time domain, and the selective numerical integration scheme is used in the present analysis. The obtained numerical examples include the effects of employed finite elements, employed grain aggregate model, grain diameter size, and grain regularity on local stress. The statistical variation around mean value is investigated for the isotropic material and the anisotropic materials having different anisotropy ratio A in elastic range. The inelastic analysis at elevated temperature is also carried out for the anisotropic materials in order to investigate the statistical variation for the anisotropic materials in strain rate effect problem and creep strain program by introducing additional six cubic slip systems into the conventional 12 octahedral slip systems inelastic range.
Substrate grain size and orientation of Cu and Cu–Ni foils used for the growth of graphene films
Authors: Robinson Zachary R. , Tyagi Parul , Murray Thomas M. , Ventrice Carl A. , Chen Shanshan , Munson Andrew , Magnuson Carl W. , Ruoff Rodney S.
Published: December 2011

Graphene growth on Cu foils by catalytic decomposition of methane forms predominantly single-layer graphene films due to the low solubility of carbon in Cu. On the other hand, graphene growth on Cu–Ni foils can result in the controlled growth of few-layer graphene films because of the higher solubility of carbon in Ni. One of the key issues for the use of graphene grown by chemical vapor deposition for device applications is the influence of defects on the transport properties of the graphene. For instance, growth on metal foil substrates is expected to result in multidomain graphene growth because of the presence of grains within the foil that exhibit a variety of surface terminations. Therefore, the size and orientation of the grains within the metal foil should influence the defect density of the graphene. For this reason, we have studied the effect of total anneal time and temperature on the orientation and size of grains within Cu foils and Cu–Ni alloy foils with a nominal concentration of 90/10 by weight. The graphene growth procedure involves preannealing the foil in a H2 background followed by the graphene growth in a CH4/H2 atmosphere. Measurements of the substrate grain size have been performed with optical microscopy and scanning electron microscopy. These results show typical lateral dimensions ranging from a few millimeters up to approximately a centimeter for Cu foils annealed at 1030 °C for 35 min and from tens of microns up to a few hundred microns for the 90/10 Cu–Ni foils annealed at 1050 °C for times ranging from 45 to 90 min. The smaller grains within the Cu–Ni foils are attributed to the higher melting point of the Cu–Ni alloy. The crystallographic orientation within each substrate grain was studied with electron backscatter diffraction, and shows that the preferred orientation for the Cu foil is primarily toward the (100) surface plane. For the 90/10 Cu–Ni foils, the orientation of the surface of the grains is initially toward the (110) plane and shifts into an orientation midway between the (100) and (111) planes as the anneal time is increased.
Interhemispheric Ice-Sheet Synchronicity During the Last Glacial Maximum
Authors: Weber Michael E. , Clark Peter U. , Ricken Werner , Mitrovica Jerry X. , Hostetler Steven W. , Kuhn Gerhard
Published: December 2011

Part of the East Antarctic Ice Sheet advanced and retreated in synchrony with Northern Hemispheric ice sheets.
Better Data for a Better Internet
Authors: Palfrey John , Zittrain Jonathan
Published: December 2011

Debates about Internet policy lack, or ignore, good data upon which to make policy decisions.
Improving Validation Practices in “Omics” Research
Authors: Ioannidis John P. A. , Khoury Muin J.
Published: December 2011

“Omics” research poses acute challenges regarding how to enhance validation practices and eventually the utility of this rich information. Several strategies may be useful, including routine replication, public data and protocol availability, funding incentives, reproducibility rewards or penalties, and targeted repeatability checks.
Robust Crossover Assurance and Regulated Interhomolog Access Maintain Meiotic Crossover Number
Authors: Rosu Simona , Libuda Diana E. , Villeneuve Anne M.
Published: December 2011

DNA breaks that drive crossing over between chromosomes in meiosis are tightly regulated in space and time.
Methodological Challenges in the Study of Primate Cognition
Authors: Tomasello Michael , Call Josep
Published: December 2011

Laboratory studies of primate cognition face the problem that captive populations of a species are not always comparable, and generalizations to natural populations are never certain. Studies of primate cognition in the field face the problem that replications are expensive and difficult, and again different populations are not always comparable. To help remedy these problems, we recommend the creation of data banks where primary data and videotapes may be deposited (perhaps as a requirement of publication) to facilitate cross-examination, replication, and, eventually, the pooling of data across investigators.
Addressing Scientific Fraud
Authors: Crocker Jennifer , Cooper M. Lynne
Published: December 2011

An interim report released in October 2011 by Tilburg University, Netherlands, concluded that one of its faculty members, social psychologist Diederik Stapel, fabricated data for numerous studies conducted over a period of 15 to 20 years.
*
The good news, of course, is that the fraud was eventually uncovered. The bad news is that it went undetected for so long and involved so many scientific articles—over 100 publications are now under investigation. The costs of the fraud for the careers of young scientists and others who worked with him, for science, and for public trust in science are devastating. As the investigation unfolds, the moment is opportune to reflect on what can be done to protect science and the public from fraud in the future.
Aging Genes: The Sirtuin Story Unravels
Authors: Couzin-Frankel Jennifer
Published: December 2011

Work that pinpointed the control of aging in a handful of genes is being taken apart by some of the scientists who made early discoveries. Efforts to replicate studies are producing conflicting results.
miRNA Processing and Human Cancer: DICER1 Cuts the Mustard
Authors: Bahubeshi Amin , Tischkowitz Marc , Foulkes William D.
Published: December 2011

Defects in the microRNA processing machinery have emerged as players in numerous tumor types and possible therapeutic targets.
An NKG2D-Mediated Human Lymphoid Stress Surveillance Response with High Interindividual Variation
Authors: Shafi Seema , Vantourout Pierre , Wallace Graham , Antoun Ayman , Vaughan Robert , Stanford Miles , Hayday Adrian
Published: December 2011

Humans mount lymphocyte stress surveillance responses to MICA, but they are individually tuned to optimal bandwidths.
PPAR for the Course in Type 2 Diabetes
Authors: Gesty-Palmer Diane
Published: December 2011

Targeting adipocyte-specific PPARγ may be a new strategy for treating type 2 diabetes.
High Frequency of Tropheryma whipplei in Culture-Negative Endocarditis
Authors: Geißdörfer Walter , Moos Verena , Moter Annette , Loddenkemper Christoph , Jansen Andreas , Tandler René , Morguet Andreas J. , Fenollar Florence , Raoult Didier , Bogdan Christian , Schneider Thomas
Published: December 2011

“Classical” Whipple's disease (cWD) is caused by
Tropheryma whipplei
and is characterized by arthropathy, weight loss, and diarrhea.
T. whipplei
infectious endocarditis (TWIE) is rarely reported, either in the context of cWD or as isolated TWIE without signs of systemic infection. The frequency of TWIE is unknown, and systematic studies are lacking. Here, we performed an observational cohort study on the incidence of
T. whipplei
infection in explanted heart valves in two German university centers. Cardiac valves from 1,135 patients were analyzed for bacterial infection using conventional culture techniques, PCR amplification of the bacterial 16S rRNA gene, and subsequent sequencing.
T. whipplei
-positive heart valves were confirmed by specific PCR, fluorescence
in situ
hybridization, immunohistochemistry, histological examination, and culture for
T. whipplei
. Bacterial endocarditis was diagnosed in 255 patients, with streptococci, staphylococci, and enterococci being the main pathogens.
T. whipplei
was the fourth most frequent pathogen, found in 16 (6.3%) cases, and clearly outnumbered
Bartonella quintana
,
Coxiella burnetii
, and members of the HACEK group (
Haemophilus
species,
Actinobacillus actinomycetemcomitans
,
Cardiobacterium hominis
,
Eikenella corrodens
, and
Kingella kingae
). In this cohort,
T. whipplei
was the most commonly found pathogen associated with culture-negative infective endocarditis.
Complete Genome and Clinicopathological Characterization of a Virulent Newcastle Disease Virus Isolate from South America
Authors: Diel Diego G. , Susta Leonardo , Cardenas Garcia Stivalis , Killian Mary L. , Brown Corrie C. , Miller Patti J. , Afonso Claudio L.
Published: December 2011

Newcastle disease (ND) is one of the most important diseases of poultry, negatively affecting poultry production worldwide. The disease is caused by Newcastle disease virus (NDV) or avian paramyxovirus type 1 (APMV-1), a negative-sense single-stranded RNA virus of the genus
Avulavirus
, family
Paramyxoviridae
. Although all NDV isolates characterized to date belong to a single serotype of APMV-1, significant genetic diversity has been described between different NDV isolates. Here we present the complete genome sequence and the clinicopathological characterization of a virulent Newcastle disease virus isolate (NDV-Peru/08) obtained from poultry during an outbreak of ND in Peru in 2008. Phylogenetic reconstruction and analysis of the evolutionary distances between NDV-Peru/08 and other isolates representing established NDV genotypes revealed the existence of large genomic and amino differences that clearly distinguish this isolate from viruses of typical NDV genotypes. Although NDV-Peru/08 is a genetically distinct virus, pathogenesis studies conducted with chickens revealed that NDV-Peru/08 infection results in clinical signs characteristic of velogenic viscerotropic NDV strains. Additionally, vaccination studies have shown that an inactivated NDV-LaSota/46 vaccine conferred full protection from NDV-Peru/08-induced clinical disease and mortality. This represents the first complete characterization of a virulent NDV isolate from South America.
Seasonal H1N1 Influenza Virus Infection Induces Cross-Protective Pandemic H1N1 Virus Immunity through a CD8-Independent, B Cell-Dependent Mechanism
Authors: Fang Yuan , Banner David , Kelvin Alyson A. , Huang Stephen S. H. , Paige Christopher J. , Corfe Steven A. , Kane Kevin P. , Bleackley R. Chris , Rowe Thomas , Leon Alberto J. , Kelvin David J.
Published: December 2011

During the 2009 H1N1 influenza virus pandemic (pdmH1N1) outbreak, it was found that most individuals lacked antibodies against the new pdmH1N1 virus, and only the elderly showed anti-hemagglutinin (anti-HA) antibodies that were cross-reactive with the new strains. Different studies have demonstrated that prior contact with the virus can confer protection against strains with some degree of dissimilarity; however, this has not been sufficiently explored within the context of a pdmH1N1 virus infection. In this study, we have found that a first infection with the A/Brisbane/59/2007 virus strain confers heterologous protection in ferrets and mice against a subsequent pdmH1N1 (A/Mexico/4108/2009) virus infection through a cross-reactive but non-neutralizing antibody mechanism. Heterologous immunity is abrogated in B cell-deficient mice but maintained in CD8
−/−
and perforin-1
−/−
mice. We identified cross-reactive antibodies from A/Brisbane/59/2007 sera that recognize non-HA epitopes in pdmH1N1 virus. Passive serum transfer showed that cross-reactive sH1N1-induced antibodies conferred protection in naive recipient mice during pdmH1N1 virus challenge. The presence or absence of anti-HA antibodies, therefore, is not the sole indicator of the effectiveness of protective cross-reactive antibody immunity. Measurement of additional antibody repertoires targeting the non-HA antigens of influenza virus should be taken into consideration in assessing protection and immunization strategies. We propose that preexisting cross-protective non-HA antibody immunity may have had an overall protective effect during the 2009 pdmH1N1 outbreak, thereby reducing disease severity in human infections.
Human Herpesvirus 8 Viral Interleukin-6 Interacts with Splice Variant 2 of Vitamin K Epoxide Reductase Complex Subunit 1
Authors: Chen Daming , Cousins Emily , Sandford Gordon , Nicholas John
Published: December 2011

Viral interleukin-6 (vIL-6) specified by human herpesvirus 8 is, unlike its cellular counterpart, secreted very inefficiently and can signal via vIL-6
2
:gp130
2
signaling complexes from the endoplasmic reticulum (ER) compartment. Intracellular, autocrine activities of vIL-6 are important for proproliferative and prosurvival activities of the viral cytokine in latently infected primary effusion lymphoma (PEL) cells. However, the molecular determinants of vIL-6 ER localization and function are unclear. Using yeast two-hybrid analysis, we identified the database-documented but uncharacterized splice variant of vitamin K epoxide reductase complex subunit 1 (VKORC1), termed VKORC1 variant 2 (VKORC1v2), as a potential interaction partner of vIL-6. In transfected cells, epitope-tagged VKORC1v2 was found to localize to the ER, to adopt a single-transmembrane (TM) topology placing the C tail in the ER lumen, and to bind vIL-6 via these sequences. Deletion mutagenesis and coprecipitation assays mapped the vIL-6-binding domain (vBD) of VKORC1v2 to TM-proximal residues 31 to 39. However, while sufficient to confer vIL-6 binding to a heterologous protein, vBD was unable to induce vIL-6 secretion when fused to (secreted) hIL-6, suggesting a VKORC1v2-independent mechanism of vIL-6 ER retention. In functional assays, overexpression of ER-directed vBD led to suppression of PEL cell proliferation and viability, effects also mediated by VKORC1v2 depletion and, as reported previously, by vIL-6 suppression. The growth-inhibitory and proapoptotic effects of VKORC1v2 depletion could be rescued by transduced wild-type VKORC1v2 but not by a vIL-6-refractory vBD-altered variant, indicating the functional relevance of the vIL-6–VKORC1v2 interaction. Notably, gp130 signaling was unaffected by VKORC1v2 or vBD overexpression or by VKORC1v2 depletion, suggesting an alternative pathway of vIL-6 activity via VKORC1v2. Combined, our data identify a novel and functionally significant interaction partner of vIL-6 that could potentially be targeted for therapeutic benefit.
Proline-Serine-Threonine Phosphatase-Interacting Protein 2 (PSTPIP2), a Host Membrane-Deforming Protein, Is Critical for Membranous Web Formation in Hepatitis C Virus Replication
Authors: Chao Ti-Chun , Su Wen-Chi , Huang Jing-Ying , Chen Yung-Chia , Jeng King-Song , Wang Horng-Dar , Lai Michael M. C.
Published: December 2011

Hepatitis C virus (HCV) reorganizes intracellular membranes to establish sites of replication. How viral and cellular proteins target, bind, and rearrange specific membranes into the replication factory remains a mystery. We used a lentivirus-based RNA interference (RNAi) screening approach to identify the potential cellular factors that are involved in HCV replication. A protein with membrane-deforming activity, proline-serine-threonine phosphatase-interacting protein 2 (PSTPIP2), was identified as a potential factor. Knockdown of PSTPIP2 in HCV subgenomic replicon-harboring and HCV-infected cells was associated with the reduction of HCV protein and RNA expression. PSTPIP2 was localized predominantly in detergent-resistant membranes (DRMs), which contain the RNA replication complex. PSTPIP2 knockdown caused a significant reduction of the formation of HCV- and NS4B-induced membranous webs. A PSTPIP2 mutant defective in inducing membrane curvature failed to support HCV replication, confirming that the membrane-deforming ability of PSTPIP2 is essential for HCV replication. Taking these results together, we suggest that PSTPIP2 facilitates membrane alterations and is a key player in the formation of the membranous web, which is the site of the HCV replication complex.
Dengue-1 Virus Clade Replacement in Thailand Associated with Enhanced Mosquito Transmission
Authors: Lambrechts Louis , Fansiri Thanyalak , Pongsiri Arissara , Thaisomboonsuk Butsaya , Klungthong Chonticha , Richardson Jason H. , Ponlawat Alongkot , Jarman Richard G. , Scott Thomas W.
Published: December 2011

Dengue viruses (DENV) are characterized by extensive genetic diversity and can be organized in multiple, genetically distinct lineages that arise and die out on a regular basis in regions where dengue is endemic. A fundamental question for understanding DENV evolution is the relative extent to which stochastic processes (genetic drift) and natural selection acting on fitness differences among lineages contribute to lineage diversity and turnover. Here, we used a set of recently collected and archived low-passage DENV-1 isolates from Thailand to examine the role of mosquito vector-virus interactions in DENV evolution. By comparing the ability of 23 viruses isolated on different dates between 1985 and 2009 to be transmitted by a present-day
Aedes aegypti
population from Thailand, we found that a major clade replacement event in the mid-1990s was associated with virus isolates exhibiting increased titers in the vector's hemocoel, which is predicted to result in a higher probability of transmission. This finding is consistent with the hypothesis that selection for enhanced transmission by mosquitoes is a possible mechanism underlying major DENV clade replacement events. There was significant variation in transmission potential among isolates within each clade, indicating that in addition to vector-driven selection, other evolutionary forces act to maintain viral genetic diversity. We conclude that occasional adaptive processes involving the mosquito vector can drive major DENV lineage replacement events.
Homolytic carbamoylation and alkoxycarbonylation of 2-aminopyrazine
Authors: Vontor Tomáš , Palát Karel , Lyčka Antonín
Published: December 2011

3-Amino-2-pyrazinecarboxylic acid amide and methyl and ethyl esters have been prepared by respective homolytic carbamoylation and alkoxycarbonylation. The identity of products has. been confirmed by the mass and NMR spectroscopies.
Nitric oxide synthase inhibition delays low-frequency stimulation-induced satellite cell activation in rat fast-twitch muscle
Authors: Martins Karen J.B. , MacLean Ian , Murdoch Gordon K. , Dixon Walter T. , Putman Charles T.
Published: December 2011

This study examined the effect of nitric oxide synthase (NOS) inhibition via Nω-nitro-l-arginine methyl ester (l-NAME) administration on low-frequency stimulation-induced satellite cell (SC) activation in rat skeletal muscle. l-NAME only delayed stimulation-induced increases in SC activity. Also, stimulation-induced increases in hepatocyte growth factor (HGF) mRNA and protein expression were only abrogated at the mRNA level in l-NAME–treated animals. Therefore, early stimulation-induced SC activation appears to be NOS-dependent, while continued activation may involve NOS-independent HGF translational control mechanisms.
A comparison of the relationship of 14 performance-based measures with frailty in older women
Authors: Theou Olga , Jones Gareth R. , Jakobi Jennifer M. , Mitnitski Arnold , Vandervoort Anthony A.
Published: December 2011

The purpose of this study was to determine which performance measures of physical function are most closely related to frailty and whether physical function is different across levels of frailty. Fifty-three community-dwelling Greek women (63–100 years) participated in this study. Participants were divided into 3 tertiles based on level of frailty as calculated from a frailty index (FI): lowest FI group (<0.19 FI), intermediate FI group (0.19–0.36 FI), and highest FI group (>0.36 FI). Performance measures tested were handgrip and knee extension muscle strength and fatigue, upper and lower body muscular endurance, walking performance, agility, and dynamic balance. The greatest proportion of variance in the FI was explained by combining all performance-based measures of physical function. The performance measures that were most closely related to frailty yet different across levels of frailty were ambulatory mobility, lower body muscular endurance, and nondominant handgrip strength. Walking at a preferred pace had the strongest relationship to frailty rather than walking at maximal pace. Grip strength of the nondominant hand had a stronger correlation with frailty compared with the dominant hand. The FI was a better predictor of physical function than chronological age. The decline in physical function accelerated after the intermediate FI tertile. Definitions of frailty need to combine performance-based measures that can identify impairments in various domains of physical function. The assessment protocols of these measures are important.
ON THE AVERAGE STATE COMPLEXITY OF PARTIAL DERIVATIVE AUTOMATA: AN ANALYTIC COMBINATORICS APPROACH
Authors: BRODA SABINE , MACHIAVELO ANTÓNIO , MOREIRA NELMA , REIS ROGÉRIO
Published: December 2011

The partial derivative automaton ([Formula: see text]) is usually smaller than other nondeterministic finite automata constructed from a regular expression, and it can be seen as a quotient of the Glushkov automaton ([Formula: see text]). By estimating the number of regular expressions that have ε as a partial derivative, we compute a lower bound of the average number of mergings of states in [Formula: see text] and describe its asymptotic behaviour. This depends on the alphabet size, k, and for growing k's its limit approaches half the number of states in [Formula: see text]. The lower bound corresponds to consider the [Formula: see text] automaton for the marked version of the regular expression, i.e. where all its letters are made different. Experimental results suggest that the average number of states of this automaton, and of the [Formula: see text] automaton for the unmarked regular expression, are very close to each other.
COMPLEXITY IN UNION-FREE REGULAR LANGUAGES
Authors: JIRÁSKOVÁ GALINA , MASOPUST TOMÁŠ
Published: December 2011

We continue the investigation of union-free regular languages that are described by regular expressions without the union operation. We also define deterministic union-free languages as languages accepted by one-cycle-free-path deterministic finite automata, and show that they are properly included in the class of union-free languages. We prove that (deterministic) union-freeness of languages does not accelerate regular operations, except for the reversal in the nondeterministic case.
ON THE AMBIGUITY OF INSERTION SYSTEMS
Authors: KUPPUSAMY LAKSHMANAN , MAHENDRAN ANAND , KRITHIVASAN KAMALA
Published: December 2011

Gene insertion and deletion are the operations that occur commonly in DNA processing and RNA editing. Based on these evolutionary transformations, a computing model has been formulated in formal language theory known as insertion-deletion systems. In this paper, we study about the ambiguity issues of insertion systems. First, we define six levels of ambiguity for insertion systems based on the components used in the derivation such as axiom, contexts and strings. Next, we show that there are inherently i-ambiguous insertion languages which are j-unambiguous for the combinations (i, j) ∈ {(5,0), (5,4), (4,3), (4,2), (3,1),(2,1), (1,0), (0,1)}. Finally, we prove an important result that the ambiguity problem of insertion systems is undecidable.
METHYLENE BLUE LOADED SILICA ENCAPSULATED MAGNETITE NANOPARTICLES: A POTENTIAL DRUG DELIVERY VECTOR FOR PHOTODYNAMIC THERAPY
Authors: ANDHARIYA NIDHI , CHUDASAMA BHUPENDRA , UPADHYAY R. V. , MEHTA R. V.
Published: December 2011

In this article, we describe synthesis of a novel drug delivery vector (DDV) for photodynamic therapy (PDT). The DDV consists of a magnetite core surrounded by a thin layer of functionalized silica. These core–shell structures are loaded with a photosensitizer (PS) drug "Methylene Blue" (MB). Magnetite nanostructures are produce by the well-established chemical co-precipitation technique and encapsulated in silica shell by modified process of hydrolysis and condensation of tetraethyl orthosilicate (TEOS). MB is grafted into the pores of silica shell by demethylation reaction. Reaction kinetics has been established for tunable loading of PS in DDV. Physical and chemical properties of composite nanostructures are determined by X-ray diffraction (XRD), dynamic light scattering (DLS), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR) and vibrating sample magnetometry (VSM). Amount of PS loading in DDV is measured by UV-Visible spectroscopy. Smaller size, biocompatibility, tunable loading of PS and capabilities of magnetic guidance, makes this DDV, a potential candidate for the treatment of malignant tumors by PDT.
AN INVESTIGATION INTO THE TORSIONAL BUCKLING OF CARBON NANOTUBES USING MOLECULAR AND STRUCTURAL MECHANICS
Authors: MAJZOOBI G. H. , PAYANDEHPEYMAN J. , NOJINI Z. BOLBOLI
Published: December 2011

In this work, the critical twist angles of two types of CNTs, zigzag and armchair of different lengths are determined using molecular and structural mechanics. The results show that the torsional buckling modes predicted by the two methods are the same. It is also shown that critical twist angle decreases as CNTs length increases. Structural mechanics underpredicts the critical angle for both armchair and zigzag nonotubes. It is also shown that the critical angle for armchair nanotubes is higher than that for zigzag nanotubes.
SPECTROSCOPIC ELLIPSOMETRIC STUDIES ON THE OPTICAL PROPERTIES OF PHOSPHORUS DOPED NANOCRYSTALLINE NiO THIN FILMS
Authors: DAS N. S. , CHATTOPADHYAY K. K. , SAHA B. , THAPA R.
Published: December 2011

Undoped and phosphorus doped nanocrystalline nickel oxide thin films have been synthesized on silicon and glass substrates by RF magnetron sputtering technique in pure Ar atmosphere. Proper phase formation was confirmed by X-ray diffraction analysis. Energy band gaps were determined using UV-Vis spectra. Formation of NiO nanoparticle of dimension ~15 nm was confirmed using HRTEM. Doping of phosphorus as an impurity was confirmed from EDX spectra and XPS studies. Spectroscopic ellipsometric studies were performed on such films and the spectra were analyzed with a suitable model. Optical constants were determined and refractive indices were found to increase with increase of phosphorus doping percentages.
GRAPHENE PRODUCED BY RADIATION-INDUCED REDUCTION OF GRAPHENE OXIDE
Authors: KUMAR PRASHANT , SUBRAHMANYAM K. S. , RAO C. N. R.
Published: December 2011

Effect of irradiation on graphene oxide by sunlight, UV light and KrF excimer laser has been investigated in detail. Both sunlight and ultraviolet light reduce graphene oxide well after prolonged irradiation, but laser irradiation produces graphene with negligible oxygen functionalities within a short time. Laser irradiation is also useful for one-step synthesis of metal particle decorated graphene. Laser irradiation of graphene oxide appears to be an efficient procedure for large-scale synthesis of graphene.
FABRICATION OF SU-8 RIDGE WAVEGUIDES BY OPTICAL LITHOGRAPHY AND THEIR CHARACTERIZATION
Authors: MAKWANI DIKSHA , VIJAYA R.
Published: December 2011

Planar and ridge waveguides are written on SU-8 thin film, coated on end polished glass substrate, by optical lithography technique at near-UV wavelengths. A significant amount of light from a diode laser at 635 nm is guided down the ridge waveguide in the experiment designed to study optical characterization. The measurement of guiding parameters such as number of modes, depth of the waveguide and refractive index are done using prism coupling technique. Simulation results on beam propagation in the SU-8 ridge waveguide (length of 2.54 cm, width of 10 μm and depth of 6 μm) show an appreciable far-field intensity profile that qualifies the waveguide design.
STUDIES ON TiO2 NANOPARTICLES AS CATALYST FOR ENHANCED DESORPTION CHARACTERISTICS OF NaAlH4
Authors: PUKAZHSELVAN D. , SINHA A. S. K. , SRIVASTAVA O. N.
Published: December 2011

TiO 2 (np) has been found to be an effective catalyst over ZrO 2 (np) for improving the hydrogen storage characteristics of NaAlH 4. TiO 2 catalyst reduces the activation energy of NaAlH 4 to a better extent than ZrO 2. In the reversibly hydrogenated materials, a substantial reduction in the dehydrogenation temperature could be achieved using TiO 2 catalyst. Such effect was not observed through ZrO 2. The activation energy of the reversibly hydrogenated NaAlH 4 catalyzed by TiO 2 nanoparticles obtained in the present study (60 kJ/mol H2 ) is smaller than that of TiO 2: NaAlH 4 starting material (101.9 kJ/mol H2 ). The stability of the intermediate phase Na 3 AlH 6 in the presence of TiO 2 catalyst was studied through TPD and TPA analysis. XRD analysis confirms that only TiO 2 gets reduced during dehydrogenation; therefore, the observed effect is attributed to the consequence of reduction of TiO 2.
GOLD NANOPARTICLES EMBEDDED ZINC OXIDE FILMS AS POSSIBLE OPTICAL FILTERS
Authors: PATRA ANURADHA , KASIVISWANATHAN S.
Published: December 2011

Multilayered structures of gold nanoparticles (AuNPs) embedded Zno films were prepared by sandwiching Au nanoparticles in between magnetron sputtered Zno films. More than 80% transmittance in visible region was observed for Zno film. For structures consisting of single and double layers of AuNPs , transmittance at ~600 nm was reduced to ~25% and ~6%, respectively. AuNPs embedded sandwiches showed a huge reduction in UV Photoluminescence that was prominent in pure Zno films, and was attributed to the interband absorption in Au .
COBALT(II)/NICKEL(II) COMPLEXES OF DITHIOACETYLACETONE [M(SacSac)2](M = Co, Ni) AS SINGLE SOURCE PRECURSORS FOR COBALT/NICKEL SULFIDE NANOSTRUCTURES
Authors: RAMASAMY KARTHIK , MANEEPRAKORN WEERAKANYA , IQBAL NASIR , MALIK MOHAMMAD AZAD , O'BRIEN PAUL
Published: December 2011

Cobalt(II)/Nickel(II) complexes of 4-thiopent-3-ene-2-thione (SacSac), [ M(SacSac) 2]( M = Co, Ni ) have been used as single source precursors (SSPs) for the preparation of cobalt/nickel sulfide thin films by aerosol-assisted chemical vapor deposition (AACVD). Cobalt or nickel sulfide nanoparticles were grown by thermal decomposition of the precursor in hot trioctylphosphine oxide (TOPO) or hexadecylamine (HDA). XRD analysis showed that all samples of cobalt or nickel sulfide are of the sulfur deficient phases ( Ni9S8, Co9S8, Ni7S6 , or Ni3S2 ). SEM and TEM analysis showed that nickel sulfide formed nanowires, nanorods and spheres; cobalt sulfide formed plate like structures and spheres. The chemical compositions of the nanoparticles can be controlled by varying temperature or the capping agents.
STRUCTURAL CHARACTERISTICS OF 70 MeV Si5+ ION IRRADIATION INDUCED NANOCLUSTERS OF GALLIUM NITRIDE
Authors: SURESH S. , GANESH V. , BALAJI M. , BASKAR K. , ASOKAN K. , KANJILAL D.
Published: December 2011

70 MeV Si ions irradiation at the liquid nitrogen temperature (77 K) induced nanoclustering on GaN epilayers grown by Metal Organic Chemical Vapor Deposition (MOCVD) are reported. HRXRD rocking curves show that there are no localized amorphization due to irradiation. Atomic force microscopy images reveal the formation of nanoclusters on the surface of the irradiated samples. On increasing the fluence the number of modified regions on the surface increases and resulted in three dimensional growth of nanocluster due to overlapping and coalescence. X-ray photoelectron spectroscopy (XPS) studies confirm that the surface features are composed of GaN . The variation of carrier concentration and hall mobility with respect to ion fluence are also studied. The effects of ion-beam induced modifications on the structural, surface characteristics and electrical properties of GaN are studied and possible mechanisms responsible for the modifications are discussed.
AMYLOID: A NATURAL NANOMATERIAL
Authors: MAJI SAMIR K.
Published: December 2011

Amyloids are stable, β-sheet-rich protein/peptides aggregates with 2–15 nm diameter and few micrometers long. It is originally associated with many human diseases such as Alzheimer's, Parkinson's and prion diseases. Amyloids are resistant to enzyme degradation, temperature changes and wide ranges of pH. Although, amyloids are hard and their stiffness is comparable to steel, a constant recycling of monomer occur inside the amyloid fibrils. It grows in a nucleation dependent polymerization manner by recruiting native soluble protein and by converting them to amyloid. These extraordinary physical properties make amyloids attractive for nanotechnological applications. Some amyloid fibrils have also evolved to perform native biological functions (functional amyloid) of the host organism. Functional amyloids are present in mammals such as amyloids of pMel17 and pituitary hormones, where they help in skin pigmentation and hormone storage, respectively. Here, the progress of utilizing amyloid fibrils for nanobiotechnological applications with particular emphasis on the recent studies that amyloid could be utilized for the formulation of peptide/protein drugs depot and how secretory cells uses amyloid for hormone storage will be reviewed.
PREPARATION OF CARBON–NITROGEN NANOTUBES (CNNTs)–POLY ETHYLENE OXIDE (PEO) COMPOSITES FILMS AND THEIR ELECTRICAL CONDUCTIVITY MEASUREMENT
Authors: YADAV RAM MANOHAR , KUMAR RAJESH , AWASTHI KALPANA , SRIVASTAVA O. N.
Published: December 2011

The present work describes the preparation characterization and electrical conductivity measurement of carbon–nitrogen (C–N) nanotubes–PEO composites films. CNNTs–PEO composite films have been prepared by using the solution cast technique and characterized by scanning electron microscope (SEM PHILIPS XL-20). The DC electrical conductivity measurements of the composite films revealed that for PEO film conductivity has been found to be ~ 7.5 × 10-8 Scm-1, and for C–N nanotubes (~ 20 wt.%)–PEO film it was found to be ~6.2 Scm-1 at room temperature. Thus, compared to the PEO film, the conductivity of the C–N nanotubes (~ 20 wt.%)–PEO composite film is eight orders of magnitude higher. The same conductivity of ~ 6.2 Scm-1 for the carbon nanotubes (CNT)–PEO composites comes out at 50 wt.% of CNT in PEO as reported earlier by our group. The conductivity increases with the increase of temperature, confirming the semiconducting nature of the C–N nanotubes–PEO composites.
CO-DEPOSITION OF IRON AND NICKEL ON NANOGRAPHITE FOR MICROWAVE ABSORPTION THROUGH FLUIDIZED BED ELECTROLYSIS
Authors: BHATTACHARYYA AMITAVA , JOSHI MANGALA
Published: December 2011

Conventional radar absorbent materials (RAM) such as iron ball (carbonyl iron) and carbon black prove less effective against modern homing devices specially those which operate at low frequency microwaves. Hybrid nanoparticles based on ferrite are found to be more suitable for such applications. Iron (Fe) coated carbon nanoparticles can also be successfully used for conducting, sensing and electromagnetic shielding or radar absorbent applications. Among the carbon nanoparticles, nanographite has its potential for such applications because of its conductivity, nanomagnetism and layered structure. Therefore, nanographite coated with Fe , nickel (Ni) or chromium is an attractive choice for microwave absorbing material. In the present study, Fe coating has been carried out on acid functionalized nanographite by a simple and novel fluidized bed electroplating process. The acid functionalization helps to adhere the coating on the nanographite surface. The electroplating of Fe–Ni alloys is recognized as an anomalous co-deposition and is characterized by a preferential deposition of the less noble metal Fe , even when the concentration of Ni in the bath was higher than that of Fe . The efficiency of the electrolytic coating of powdered material is strongly affected by the applied current density, the rotation speed, the average size of the particles and the density of the electrolyte-powder suspension. The nanoparticles were further dispersed in polyurethane matrix and cast into nanocomposite films. The microwave absorption property observed in the frequency range 300 MHz to 1.5 GHz shows that a very thin coating of Fe–Ni helps to absorb the microwave quite efficiently. Fe–Ni coated functionalized nanographite synthesized by this method is thus an effective microwave absorbent material and can find potential use in several defence applications as specialty coatings for fighter aircrafts/radomes and other coated textiles used for aerial surveillance etc.