bluuebunny/crossref_metadata_2025 huggingface dataset:
High performance platinum-silicided p-type Schottky barrier metal-oxide-semiconductor field-effect transistors scaled down to 30 nm
Authors: Jun Myungsim , Park Youngsam , Hyun Younghoon , Zyung Taehyoung , Jang Moongyu , Choi Sung-Jin
Published: May 2011

Platinum-silicided p-type Schottky barrier metal-oxide-semiconductor field-effect-transistors with sizes varying from 350 to 30 nm were fabricated on silicon-on-insulator substrates. Threshold voltage, subthreshold swing, drain-induced barrier lowering, and saturation current were investigated as a function of gate length and channel width. The device with a gate length of 30 nm showed excellent short channel characteristics with an on/off current ratio larger than 107, an off-leakage current less than 10 pA/μm, and a subthreshold swing of 110 mV/decades.
Ultranarrow bandpass filter with wide nontransmission region composed of randomly distributed layer thicknesses
Authors: Chen Guibin , Yu Haichun
Published: May 2011

By introducing disorder into a periodic Fabry–Pérot type of ultranarrow bandpass (UNBP) filter, the nontransmission region of the filter can be remarkably enlarged while maintaining the UNBP. The filter that was used was fabricated by using electronic beam evaporation. The introduction of disorder into the periodic structure ensures that the nontransmission region is significantly extended by 14%, with a very narrow bandpass of full width at half maximum <1.9 nm and intensity=80%.
Characteristics of PMN-PZT ferroelectric electron emitters with three-dimensional emission sites formed by chemical etching
Authors: Sugiyama Tomohiko , Ohwada Iwao , Nanataki Tsutomu , Moriguchi Yukihisa , Eryu Osamu , Ichimura Masaya , Gomi Manabu
Published: May 2011

Pb(Mg1/3N2/3)O3-PbZrO3-PbTiO3 (PMN-PZT) ferroelectric electron emitters with a novel electrode structures were formed by photolithography and chemical etching to investigate their electron emission characteristics. For the electron emitter formed with the most suitable etching time, the electron emission density was 17 nC/cm2. An electric potential distribution was simulated to clarify the effects of the vacuum gap, and results confirmed that the vacuum gap produces an electric field that leads electrons from the ferroelectric surface to the surrounding space.
Response to Comment on “A Persistent Oxygen Anomaly Reveals the Fate of Spilled Methane in the Deep Gulf of Mexico”
Authors: Kessler John D. , Valentine David L. , Redmond Molly C. , Du Mengran
Published: May 2011

We hypothesized that methane from the Deepwater Horizon oil spill was quantitatively consumed and presented results from four tests supporting this finding. Subsequent published studies provide further support for our conclusions. We refute the criticisms by Joye
et al
., which are incorrect, internally contradictory, based on flow-rate estimates that exceed consensus values, and overall do not disprove our hypothesis or invalidate its underlying assumptions.
TFEB Links Autophagy to Lysosomal Biogenesis
Authors: Settembre Carmine , Di Malta Chiara , Polito Vinicia Assunta , Arencibia Moises Garcia , Vetrini Francesco , Erdin Serkan , Erdin Serpil Uckac , Huynh Tuong , Medina Diego , Colella Pasqualina , Sardiello Marco , Rubinsztein David C. , Ballabio Andrea
Published: May 2011

Starvation activates a transcriptional program controlling autophagosome formation, lysosome fusion, and substrate degradation.
High Pre-Eruptive Water Contents Preserved in Lunar Melt Inclusions
Authors: Hauri Erik H. , Weinreich Thomas , Saal Alberto E. , Rutherford Malcolm C. , Van Orman James A.
Published: May 2011

Primitive magmatic melt inclusions from the Moon contain as much water as some terrestrial mid-ocean ridge magmas.
Chameleon Magnets
Authors: Žutić Igor , Černe John
Published: May 2011

An external voltage can switch ferromagnetism on and off in a material at room temperature, which may add new functionality to electronics.
Innovation Needs Novel Thinking
Authors: Leshner Alan I.
Published: May 2011

Science, Technology, and Innovation are critical drivers of economic growth and national well-being. As a result, investing in them has become a source of hope for many countries, both rich and poor. But innovation demands that novel ideas be pursued, and the science and technology (S&T) enterprise may not be well structured, in the United States and elsewhere, to attract, recognize, and exploit new ideas. Some long-held traditions and modes of operation need to be reexamined to ensure that the system is optimized as an engine for advancing society's goals.
Manta Machines
Authors: Pennisi Elizabeth
Published: May 2011

By observing manta rays in the wild, modeling them, and building robots, researchers are learning how these agile animals ply the oceans.
Comparison of Passively Transferred Antibodies in Bighorn and Domestic Lambs Reveals One Factor in Differential Susceptibility of These Species to Mannheimia haemolytica-Induced Pneumonia
Authors: Herndon Caroline N. , Shanthalingam Sudarvili , Knowles Donald P. , Call Douglas R. , Srikumaran Subramaniam
Published: May 2011

Mannheimia haemolyticaconsistently causes fatal bronchopneumonia in bighorn sheep (BHS;Ovis canadensis) under natural and experimental conditions. Leukotoxin is the primary virulence factor of this organism. BHS are more susceptible to developing fatal pneumonia than the related speciesOvis aries(domestic sheep [DS]). In BHS herds affected by pneumonia, lamb recruitment is severely impaired for years subsequent to an outbreak. We hypothesized that a lack of maternally derived antibodies (Abs) againstM. haemolyticaprovides an immunologic basis for enhanced susceptibility of BH lambs to population-limiting pneumonia. Therefore, the objective of this study was to determine the titers of Abs directed againstM. haemolyticain the sera of BH and domestic lambs at birth through 12 weeks of age. Results revealed that BH lambs had approximately 18-fold lower titers of Ab against surface antigens ofM. haemolyticaand approximately 20-fold lower titers of leukotoxin-neutralizing Abs than domestic lambs. The titers of leukotoxin-neutralizing Abs in the serum and colostrum samples of BH ewes were approximately 157- and 50-fold lower than those for domestic ewes, respectively. Comparatively, the higher titers of parainfluenza 3 virus-neutralizing Abs in the BH lambs ruled out the possibility that these BHS had an impaired ability to passively transfer Abs to their lambs. These results suggest that lower levels of leukotoxin-neutralizing Abs in the sera of BH ewes, and resultant low Ab titers in their lambs, may be a critical factor in the poor lamb recruitment in herds affected by pneumonia.
Emergence of Extended-Spectrum β-Lactamase (CTX-M-15 and CTX-M-14)-Producing Nontyphoid Salmonella with Reduced Susceptibility to Ciprofloxacin among Food Animals and Humans in Korea
Authors: Tamang Migma Dorji , Nam Hyang-Mi , Kim Tae-Sun , Jang Geum-Chan , Jung Suk-Chan , Lim Suk-Kyung
Published: May 2011

Twenty of 1,279 nontyphoid
Salmonella
strains isolated from food animals and humans produced CTX-M-type extended-spectrum β-lactamase. All expressed CTX-M-15, except two which coexpressed CTX-M-14 and TEM-1. Insertion sequence IS
Ecp1
was identified upstream of
bla
CTX-M
genes. The
bla
CTX-M-15
and
bla
CTX-M-14
genes were disseminated by large conjugative IncFIIs and IncI1-Iγ plasmids, respectively.
Interleukin-28B Genotyping by Melt-Mismatch Amplification Mutation Assay PCR Analysis Using Single Nucleotide Polymorphisms rs12979860 and rs8099917, a Useful Tool for Prediction of Therapy Response in Hepatitis C Patients
Authors: Fonseca-Coronado Salvador , Vaughan Gilberto , Cruz-Rivera Mayra Yolanda , Carpio-Pedroza Juan Carlos , Ruiz-Tovar Karina , Ruiz-Pacheco Juan Alberto , Escobar-Gutiérrez Alejandro
Published: May 2011

Several studies have identified associations between single nucleotide polymorphisms (SNPs) occurring near the interleukin-28B (IL-28B) gene and response to antiviral treatment among hepatitis C virus (HCV) patients. Here, we describe a reliable melt-mismatch amplification mutation assay (melt-MAMA) PCR-based genotyping method for IL-28B which can be used in the management of HCV patients, helping to better define the course of therapy.
Expanded Potential for Recombinant Trisegmented Lymphocytic Choriomeningitis Viruses: Protein Production, Antibody Production, and
In Vivo
Assessment of Biological Function of Genes of Interest
Authors: Popkin Daniel L. , Teijaro John R. , Lee Andrew M. , Lewicki Hanna , Emonet Sebastien , de la Torre Juan Carlos , Oldstone Michael
Published: May 2011

The recombinant engineering of trisegmented lymphocytic choriomeningitis virus (LCMV) to express two genes of interest was recently reported. We used this technology to efficiently express green fluorescent protein (GFP) and the immunoregulatory gene product interleukin-10 (IL-10)
in vitro
, assess IL-10 function
in vivo
during viral meningitis, and generate specific, robust monoclonal antibody responses to IL-10. Tripartite viruses were attenuated in wild-type and TLR7
−/−
mice. However, IFNAR1
−/−
mice sustained systemic viral replication when 2 nucleotide substitutions from a persistent LCMV variant were present. These findings demonstrate the utility of tripartite LCMV
in vitro
and
in vivo
to study genes in the context of a well-defined model system.
Rhesus Monkey Rhadinovirus ORF57 Induces gH and gL Glycoprotein Expression through Posttranscriptional Accumulation of Target mRNAs
Authors: Shin Young C. , Desrosiers Ronald C.
Published: May 2011

Open reading frame 57 (ORF57) of gamma-2 herpesviruses is a key regulator of viral gene expression. It has been reported to enhance the expression of viral genes by transcriptional, posttranscriptional, or translational activation mechanisms. Previously we have shown that the expression of gH and gL of rhesus monkey rhadinovirus (RRV), a close relative of the human Kaposi's sarcoma-associated herpesvirus (KSHV), could be dramatically rescued by codon optimization as well as by ORF57 coexpression (J. P. Bilello, J. S. Morgan, and R. C. Desrosiers, J. Virol.82:7231–7237, 2008). We show here that ORF57 coexpression and codon optimization had similar effects, except that the rescue of expression by codon optimization was temporally delayed relative to that of ORF57 coexpression. The transfection of gL mRNA directly into cells with or without ORF57 coexpression and with or without codon optimization recapitulated the effects of these modes of induction on transfected DNA. These findings suggested an important role for the enhancement of mRNA stability and/or the translation of mRNA for these very different modes of induced expression. This conclusion was confirmed by several different measures of gH and gL mRNA stability and accumulation with or without ORF57 coexpression and with or without codon optimization. Our results indicate that RRV gH and gL expression is severely limited by the stability of the mRNA and that ORF57 coexpression and codon optimization independently induce gH and gL expression principally by allowing accumulation and translation of these mRNAs.
A chronoamperometric study of the oxidative nucleation of niazid and isoniazid on mercury electrodes in basic solutions
Authors: Ruiz Montoya Mercedes , Pintado Sara , Rodríguez Mellado José Miguel
Published: May 2011

Using chronoamperometric measurements at pH 12 it is shown that the oxidation mechanism of niazid adsorbed on the mercury electrode changes with respect to the mechanism reported in the literature for the electrooxidation of the molecules reaching the electrode by diffusion. A compact monolayer of niazid molecules is formed on the electrode surface, being the hydrazide oxidized through a two-electron process. The oxidation product is not able to dissociate a H+ ion, and the oxidation process does not proceeds beyond. For isoniazid the monolayer never becomes compact.
Detection and follow-up of cardiovascular disease and risk factors in the Southern Cone of Latin America: the CESCAS I study
Authors: Rubinstein Adolfo Luis , Irazola Vilma Edith , Poggio Rosana , Bazzano Lydia , Calandrelli Matías , Lanas Zanetti Fernando Tomas , Manfredi Jose Anibal , Olivera Héctor , Seron Pamela , Ponzo Jacqueline , He Jiang
Published: May 2011

Introduction

Cardiovascular diseases (CVD) are increasing throughout the world and cause 16.7 million deaths each year, 80% of which occur in low and middle income countries. In Argentina, Chile and Uruguay, the available data on cardiovascular risk factors come predominantly from cross-sectional studies that are principally based on self-report or studies conducted with small convenience samples. The CESCAS I study will generate reliable estimates of the prevalence and distribution of and secular trends in CVD and its risk factors in this region.

Methods and analysis

CESCAS I is an observational prospective cohort study with a multistage probabilistic sample of 8000 participants aged 35–74 years from four mid-sized cities representing the Southern Cone of Latin America: Bariloche and Marcos Paz in Argentina, Temuco in Chile and Pando-Barros Blancos in Uruguay. In the first phase, baseline data regarding exposure to risk factors and prevalence of CVD will be collected in two stages: (1) in homes and (2) in health centres. Information will be gathered on medical history, risk factors, lifestyles and health utilisation through specific questionnaires, physical measurements, an ECG and an overnight, fasting blood sample to measure levels of serum lipids, glucose and creatinine. In the second phase, annual follow-up data will be obtained on the incidence rate of CVD events and the association between exposure and events.

Ethics and dissemination

The protocol has obtained formal ethics approval from institutional review boards in Argentina, Chile, Uruguay and the USA. The lack of follow-up studies has prevented Argentina, Chile and Uruguay from implementing risk factor stratification and management strategies at a population level. However, the CESCAS I study data will help the development of public health strategies based on primary care intervention, thus helping to improve cardiovascular health in this region.
The views of genitourinary medicine (GUM) clinic users on unlinked anonymous testing for HIV: evidence from a pilot study of clinics in two English cities
Authors: Datta Jessica , Kessel Anthony , Wellings Kaye , Nanchahal Kiran , Marks Dalya , Kinghorn George
Published: May 2011

A study was undertaken of the views of users of two genitourinary medicine (GUM) clinics in England on unlinked anonymous testing (UAT) for HIV. The UAT programme measures the prevalence of HIV in the population, including undiagnosed prevalence, by testing residual blood (from samples taken for clinical purposes) which is anonymised and irreversibly unlinked from the source. 424 clinic users completed an anonymous questionnaire about their knowledge of, and attitudes towards, UAT. Only 1/7 (14%) were aware that blood left over from clinical testing may be tested anonymously for HIV. A large majority (89%) said they would agree to their blood being tested, although 74% wanted the opportunity to consent. These findings indicate broad support for UAT of blood in a group of patients whose samples are included in the HIV surveillance programme. The findings suggest the need for greater attention to be given to the provision of information and, if replicated in a larger survey, may justify a reappraisal of UK policy on UAT.
Workplace and individual risk factors for carpal tunnel syndrome
Authors: Burt Susan , Crombie Ken , Jin Yan , Wurzelbacher Steve , Ramsey Jessica , Deddens James
Published: May 2011

Objectives

To quantify the relationship between workplace physical factors, particularly hand activity level (HAL) and forceful exertion and carpal tunnel syndrome (CTS), while taking into account individual factors. To compare quantitative exposure assessment measures with more practical ratings-based measures.

Methods

In a group of healthcare and manufacturing workers, each study participant's job tasks were evaluated for HAL, forceful exertion and other physical stressors and videotaped for further analysis, including frequency and duration of exertion and postural deviation. Electrodiagnostic testing of median and ulnar nerves and questionnaires were administered to all participants. A CTS case required median mononeuropathy and symptoms on hand diagrams in fingers 1–3. Multiple logistic regression models were used to analyse associations between job and individual factors and CTS.

Results

Of 477 workers studied, 57 (11.9%) were dominant hand CTS cases. Peak force ≥70% maximum voluntary contraction versus <20% maximum voluntary contraction resulted in an OR of 2.74 (1.32–5.68) for CTS. Among those with a body mass index ≥30, the OR for ≥15 exertions per minute was 3.35 (1.14–9.87). Peak worker ratings of perceived exertion increased the odds for CTS by 1.14 (1.01–1.29) for each unit increase on the 10-point scale. The odds for CTS increased by 1.38 (1.05–1.81) for each unit increase on the HAL 10-point scale among men, but not women. Combined force and HAL values above the ACGIH TLV for HAL resulted in an OR of 2.96 (1.51–5.80) for CTS.

Discussion/Conclusions

Quantitative and ratings-based job exposure measures were each associated with CTS. Obesity increased the association between frequency of exertion and CTS.
Republished paper: Assessing and improving safety culture throughout an academic medical centre: a prospective cohort study
Authors: Paine Lori A , Rosenstein Beryl J , Sexton J Bryan , Kent Paula , Holzmueller Christine G , Pronovost Peter J
Published: May 2011

Objectives

To describe the authors' hospital-wide efforts to improve safety climate at a large academic medical centre.

Design and setting

A prospective cohort study used multiple interventions to improve hospital-wide safety climate. 144 clinical units in an urban academic medical centre are included in this analysis.

Interventions

The comprehensive unit-based safety programme included steps to identify hazards, partner units with a senior executive to fix hazards, learn from defects, and implement communication and teamwork tools. Hospital-level interventions were also implemented.

Main outcome measures

Safety climate was assessed annually using the safety attitudes questionnaire. The safety culture goal was to meet or exceed the 60% minimum positive score or improve the score by ≥10 points.

Results

Response rates were 77% (2006) and 79% (2008). For safety climate, 55% of units in 2006 and 82% in 2008 achieved the culture goal. For teamwork climate, 61% of units in 2006 and 83% in 2008 achieved the culture goal. The mean safety climate improvement (difference score) for 79 units at or above 60% in 2006 was 0.201 in 2008; the mean improvement for the 65 units below the threshold was 18.278. The mean teamwork climate improvement (difference score) for the 89 units at or above 60% in 2006 was 0.452 in 2008; the mean improvement for the 55 units below the threshold was 16.176. Climate scores improved significantly from 2006 to 2008 in every domain except stress recognition.

Conclusions

Hospital-wide interventions were associated with improvements in safety climate at a large academic medical centre.
Use of recent and historical records to estimate status and trends of a rare and imperiled stream fish, Percina jenkinsi (Percidae)
Authors: Hagler Megan M. , Freeman Mary C. , Wenger Seth J. , Freeman Byron J. , Rakes Patrick L. , Shute J.R.
Published: May 2011

Rarely encountered animals may be present but undetected, potentially leading to incorrect assumptions about the persistence of a local population or the conservation priority of a particular area. The federally endangered and narrowly endemic Conasauga logperch ( Percina jenkinsi ) is a good example of a rarely encountered fish species of conservation concern, for which basic population statistics are lacking. We evaluated the occurrence frequency for this species using surveys conducted with a repeat-observation sampling approach during the summer of 2008. We also analyzed museum records since the late 1980s to evaluate the trends in detected status through time. The results of these analyses provided support for a declining trend in this species over a portion of its historical range, despite low estimated detection probability. We used the results to identify the expected information return for a given level of monitoring where the sampling approach incorporates incomplete detection. The method applied here may be of value where historic occurrence records are available, provided that the assumption of constant capture efficiency is reasonable.
Understanding limits to cod and haddock separation using size selectivity in a multispecies trawl fishery: an application of FISHSELECT
Authors: Sistiaga Manu , Herrmann Bent , Nielsen Kåre N. , Larsen Roger B.
Published: May 2011

This investigation demonstrates how a multidisciplinary approach based on the FISHSELECT framework, sea trial data, underwater recordings, and laboratory investigations of netting can be applied to size selectivity studies and related management issues. We studied the morphological characteristics of Atlantic cod ( Gadus morhua ) and haddock ( Melanogrammus aeglefinus ) in the Barents Sea bottom trawl fishery. The differences between the L50 values (i.e., the size at which a fish has a 50% chance of being retained) that were recorded for the two species during sea trials can to a large extent be explained by the morphological differences between them. Because of these morphological differences, L50 is always larger for cod than for haddock with the grid and codend setup commonly used in the area. While catch separation of cod and haddock is a management objective in the Barents Sea, we demonstrate that the morphological differences between the species and the grid and codend setup in force today limit achievable differences in L50 to 5.5 cm. Furthermore, we show that for this fishery, the scope for increasing L50 differences between these species by changing the mesh shape configuration of the codend is minimal.
Effects of substrate condition on habitat use and survival by white sturgeon (Acipenser transmontanus) larvae and potential implications for recruitment
Authors: McAdam Steven O.
Published: May 2011

To understand links between substrate and recruitment of white sturgeon ( Acipenser transmontanus ), I evaluated the effects of substrate condition on larval drift, hiding, and predation between hatch and 15 days posthatch (dph). Over porous substrates (small gravel = 1.2–1.9 cm; medium gravel = 2.5–5.0 cm; cobble = 10–15 cm), rapid interstitial hiding was observed from 0 to 6 dph at low water velocity (4 cm·s–1), whereas larvae drifted in response to nonporous substrates (sand < 0.2 cm; embedded cobble). Velocities of 20 cm·s–1 led to significantly lower drift only at 1 dph over small gravel. Hiding occurred an average of 2.0–13.3 s after release at 0–6 dph. Predation by sculpins ( Cottus  spp.) on larval sturgeon also decreased significantly in response to porous substrates at 1 dph. The strongest expression of increased hiding and decreased predation when small gravel was available suggests that yolksac larvae prefer small interstitial spaces created by that substrate. Considering behavioural responses in preferred natural spawning habitat suggests yolksac larvae predominantly hide in the vicinity of spawning locations. Identification of strong effects of substrate condition on age-specific drift and survival suggests that substrate degradation may contribute to recruitment limitations for sturgeon.
DIODE p-i-n-STRUCTURES BASED ON NEUTRON DOPED Si1-xGex-ALLOYS
Authors: CHEKANOV V. , YEVSEYEV V. , KURYATKOV V. , PROKOFYEVA T.
Published: May 2011

Photoelectric properties of neutron transmutation doped (NTD) Si 1-x Ge x solid solutions (alloy) with variable composition are presented. It is shown that the application of NTD method to Si 1-x Ge x solid solutions with gradient composition (x = 0–2 at.%) along an ingot allows to receive p-i-n-structures with typical diode characteristics. We studied electrical and photoelectrical properties of that structure. Deep level transient spectroscopy of p-i-n diode has revealed the energy levels in the forbidden zone of Si 1-x Ge x, connected with transmutation Se impurity. It is established that p-i-n-structures possess high spectral sensitivity with a maximum at hν = 1.2–1.5 eV (300 K). Possible application of Si 1-x Ge x-alloys in development of uncooled photodiodes with large effective area was considered.
A FIRST-PRINCIPLE INVESTIGATION OF BORON- AND NITROGEN-DOPED HETEROFULLERENES
Authors: GARG ISHA , DHARAMVIR KEYA , JINDAL V. K. , SHARMA HITESH
Published: May 2011

A systematic study of structural, electronic and vibrational properties of boron- and nitrogen-doped heterofullerenes has been performed. N and B doping lead to the structural deformation, and the dopant has a tendency to occupy a single position in a pentagon and two positions in a hexagon which are not adjacent. B -substitution produces clusters of greater thermodynamic stability than N substitution. The C–N and C–B bond lengths lie in the range of 1.40–1.44 Å and 1.53–1.57 Å for hexagon–hexagon (6, 6) and 1.39–1.46 Å and 1.55–1.60 Å at pentagon–hexagon (5, 6) interfaces, respectively. The Mulliken charge analysis shows a charge transfer of -0.30 to -0.45 electrons from N to C atoms; B atom act as electron acceptors with charge gain ranging between -0.59 to -0.70 electrons. N - and B -doping in fullerene molecules present an interesting way to alter electronic and chemical properties of the C 60 molecule for useful device applications.
TEMPLATE SYNTHESIS OF NICKEL, COBALT, AND NICKEL HEXACYANOFERRATE NANODOT, NANOROD, AND NANOTUBE ARRAYS
Authors: KANT KRISHNA , LOSIC DUSAN , SABZI REZA EMAMALI
Published: May 2011

This work presents template synthesis of ordered arrays of nickel, cobalt and nickel hexacyanoferrates ( NiHCF ) with several distinct morphologies such as dots, rods, and tubes. Anodic alumina oxide (AAO) with preferred pore diameters and thickness was fabricated by electrochemical anodization of aluminum used as template. Ni and Co nanostructures inside AAO template were prepared by electrodeposition using galvanostatic method. NiHCF nanostructures were prepared by electrochemical oxidation of Ni using cyclic voltametry (CV) in the presence of hexacyanoferrate ions. The morphology, chemical, and functional properties of prepared nanostructures were investigated by scanning electron microscopy (SEM), energy-dispersive X-ray microscopy (EDAX), and electrochemical methods. The electrocatalytic properties of NiHCF nanorod arrays electrode and their potential for the detection of hydrogen peroxide and biosensing application were demonstrated.
ANNEALING EFFECT ON THE DARK ELECTRICAL TRANSPORT AND ABSORBANCE SPECTRA OF CHEMICAL BATH DEPOSITED CdS NANOCRYSTALLITES
Authors: SINGH NAOREM SHANTA , SINGH WAIKHOM SHAMBHUNATH , SINGH SHOUGAIJAM DORENDRAJIT
Published: May 2011

We report here our investigations on dark DC resistivity and optical absorption of chemical bath deposited CdS thin films prepared by chemical bath deposition. Crystallite sizes of about 30 nm are found from XRD using Scherrer formula with an added term for strain broadening. Energy-dispersive X-ray measurement shows correct stoichiometry of Cd and S atomic ratio. The grain size of the as-deposited film determined from both AFM and TEM is found to be ~180 nm. On vacuum annealing, the dark resistivity decreases from ~109 to 106 Ω-cm. Dark resistivity variation of as-deposited and vacuum-annealed films with temperature in the temperature region (95–350 K) reveals that each film exhibits two types of conduction in this temperature region. From the optical absorption study the optical band gap of as-deposited film is found to be ~2.29 eV.
GROWTH OF INDIUM-RICH NANOCRYSTALLINE INDIUM GALLIUM NITRIDE THIN FILMS BY MODIFIED ACTIVATED REACTIVE EVAPORATION
Authors: MEHER S. R. , BIJU KUYYADI P. , JAIN MAHAVEER K.
Published: May 2011

Indium-rich In x Ga 1-x N thin films were prepared on glass substrates by a mixed source modified activated reactive evaporation technique. All the films exhibit hexagonal wurtzite structure preferentially oriented along the c-axis. The band gap values obtained through Urbach fitting of the absorption edge were found to be in good agreement with the values obtained from photoluminescence spectra. The decrease in band gap below 1.9 eV (i.e., for pure InN ) for indium-rich films is mainly due to the compensation of Burstein–Moss shift due to gallium incorporation into the lattice which is further confirmed from the carrier concentration measurements.
DEFECT EVOLUTION AND STRUCTURAL IMPROVEMENT IN LOW ENERGY ION IRRADIATED CARBON NANOTUBES: MICROSCOPIC AND SPECTROSCOPIC STUDIES
Authors: SINGH DILIP K. , IYER PARAMESWAR K. , GIRI P. K.
Published: May 2011

The capability of graphitic networks to reorganize their structures under irradiation of energetic particles provides the tool for nano-engineering of carbon nanotubes (CNTs). We have studied the effect of 30 keV N + ion irradiation with three different fluences 1012, 1013, and 1014 ions/cm2 on the structural and spectroscopic properties of single-walled carbon nanotubes (SWNTs) and multiwalled carbon nanotubes (MWNTs). Irradiation-induced structural defects and coalescence of the nanotubes are studied using high-resolution transmission electron microscopy (HRTEM). Upon irradiation, some of the radial breathing modes in Raman spectra disappear due to conversion from single-walled to multiwalled structure. We observed a systematic change in intensity of the intermediate frequency mode (IFM) with increasing dose of ion-irradiation and these IFM modes are attributed to structural defects of SWNTs. Dramatic improvement in the intensity ratio G-band to D-band (at ~1335 cm-1) for ion fluence of 1013 ions/cm2 indicates improved graphitic structure as a result of reconstruction. Similarly, X-ray Photoelectron spectroscopy studies show improvement in the amount of sp 2 carbon upon 1013 ions/cm2 N + ion irradiation dose. At a higher dose (1014 N + ions/cm 2), vacancy and bent structures having Stone–Wales defects were observed in HRTEM, whereas MWNTs show formation of surface hillock like protrusions leading to formation of fullerene-like structures.
POTENTIAL OF NANOCHITOSAN-COATED INERT SUBSTRATE AS AN ANTIBACTERIAL WATER FILTER
Authors: RAJENDRAN R. , BALAKUMAR C. , RADHAI R. , DEVAKI N.
Published: May 2011

The current study deals with the aspects of surface modification of Polyurethane (PU) foam using chitosan nanoparticles to purify the water from bacteria. The present work also addresses the synthesis and characterizations of chitosan nanoparticles. The particles were characterized by evaluating their topography, size via SEM. These nanoparticles were then coated onto PU foams in order to evaluate these filter samples for purification efficiency through standardized test procedures. The percentage bacterial reduction with the chitosan nanoparticle coated PU foam was 100%, whereas it was only 58.33% with uncoated PU foam. The results were confirmed by flow test which showed coliform count of 30 CFU/mL in the input water, whereas in the Output water the coliform count was 0. Hence, from the overall results it can be confirmed that the PU foams coated with chitosan nanoparticles have good purification efficiency and can be used as an antibacterial water filter.
BIOCONJUGATED QUANTUM DOTS BASED RAPID DETECTION OF PATHOGENIC BACTERIA FROM WATER SAMPLES
Authors: JACKERAY RICHA , SINGH GURPAL , JAIN SWATI , ABID CKV ZAINUL , SINGH HARPAL , ZAIDI NEELAM H. , SONI UDIT , SAPRA SAMEER , SHRIVASTAV T. G.
Published: May 2011

A sensitive and rapid method for the detection of pathogenic bacteria (Salmonella typhi) in water sample was developed using core-shell CdSe / ZnS quantum dots (QDs) as fluorescence label. Surface-functionalized core-shell quantum dots were synthesized by successive ion layer adsorption and reaction (SILAR) technique and were made hydrophilic by ligand exchange method. Developed hydrophobic and hydrophilic QDs were characterized by transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), and spectrofluorimetry. Carboxy- terminated QDs were conjugated with bacteria-specific antibodies (S. typhi-specific IgG) for the preparation of photostable fluorescent label and were characterized by various techniques like spectrofluorimetry and enzyme-linked immunosorbent assay (ELISA) for their photoluminescence and successful bioconjugation. Antibody (Ab)-conjugated QDs were incubated with bacteria-contaminated water for S. typhi detection. Microscopic images and spectral profile of bacteria–Ab conjugated QDs complex were recorded by confocal laser scanning microscopy (CLSM). A sensitivity of 103 organisms/mL of targeted bacteria (S. typhi) could be attained in a period of about 2 h.
CONSOLIDATION OF CNT-REINFORCED AA4032 NANOCOMPOSITES BY ECAP
Authors: SARAVANAN M. S. SENTHIL , BABU S. P. KUMARESH , SIVAPRASAD K. , RAVISANKAR B. , SUSILA P. , MURTY B. S.
Published: May 2011

The present work emphasizes on the synthesis of CNT-reinforced nanocrystalline AA4032 alloy powders and their consolidation by equal channel angular pressing (ECAP). Nanocrystalline AA4032 alloy reinforced with 2 wt% CNTs was produced by high-energy ball milling. The XRD analysis and TEM observation revealed the formation of nanocrystalline AA4032 alloy and uniform distribution of CNTs in the nanocrystalline matrix. The nanocomposite powders were canned in commercially pure aluminum sheath and subjected to ECAP for consolidation. More than 98% of density was achieved after four passes in route BA at the center of the can. The hardness obtained is around 218 HV5.0 after four passes in the core of alloy with 2 wt% of CNTs. Increase in hardness was significant even with minimum addition of CNTs.
BLUE-GREEN LUMINESCENCE OF CHEMICALLY SYNTHESIZED MWCNT/CdS NANOHYBRID STRUCTURE
Authors: PAUL RIMA , KUMBHAKAR P. , MITRA A. K.
Published: May 2011

A simple inexpensive wet chemical technique at room temperature to prepare hybrid structure of multiwalled carbon nanotubes (MWCNT) and cadmium sulfide ( CdS ) nanoparticles has been reported in this paper. Cadmium sulfide nanocrystals of average size 5 nm have been synthesized and attached with the surfaces of MWCNTs. The hybrid material is characterized by high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), and Raman spectroscopy. Interesting optical properties of the composite are revealed through UV–visible and photoluminescence (PL) spectroscopy. Significant blue-green PL emission covering a region from 450–600 nm wavelength has been observed when excited by UV radiation of 220–240 nm wavelength. Sharp emission peak has been obtained and this may find wide applications in optical sensors and optoelectronic devices.
MODIFICATION OF TRANSPORT AND MAGNETIC BEHAVIOR IN HALF-DOPED CHARGE-ORDERED NANOCRYSTALLINE MANGANITE Sm0.5Ca0.5MnO3
Authors: GIRI S. K. , NATH T. K.
Published: May 2011

Half-doped Sm0.5Ca0.5MnO3 nanoparticles with varying particle size down to ~14 nm are synthesized by chemical "pyrophoric reaction" route and their electronic transport and magnetotransport behaviors are investigated in detail in order to understand the nanodimensional size effect on the charge ordering in manganites. The experimental result shows that reduction of particle size (having same chemical composition) down to nanometer scale destabilizes the charge ordering. Weak ferromagnetism and metal–insulator transition are observed in the sample having lowest particle size (14 nm) as a consequence of such suppression of charge ordering. The observed phenomena have been attributed to enhanced surface pressure in the nanoparticles.
COUPLED EFFECT OF STRAIN AND MAGNETIC FIELD ON ELECTRONIC BAND STRUCTURE OF GRAPHENE
Authors: SINGH YASHUDEEP , MAHAPATRA D. ROY
Published: May 2011

Hofstadter's fractal energy spectrum, which is also called Hofstadter butterfly, remained as one of the most interesting topics of condensed matter physics for decades. We study, in this paper, how different patterns of energy spectrum emerge when a graphene sheet is subjected to in-plane uniaxial and shear strain in the presence of transverse magnetic field. We discuss these patterns in the context of opening of the electronic energy band structure of graphene. We thus provide a unified framework for graphene under the coupled effect of strain and magnetic field. Due to such coupling, the energy bandgap opens when certain threshold of strain in the zigzag direction of graphene is crossed. The threshold strain value depends on the rationality of the parameter ϕ/ϕo, i.e., the ratio of magnetic flux through the deformed hexagonal plaquette and the quantum flux (h/e). Numerical results shows that the energy bandgap depends nonlinearly on the magnitude of strain, and that the threshold strain and energy gap decrease with decreasing magnetic field.
STRUCTURAL, ELECTRONIC, AND OPTICAL PROPERTIES OF ZnxSy (x + y = 2 TO 4) NANOCLUSTERS: A B3LYP-DFT STUDY
Authors: YADAV P. S. , PANDEY D. K. , AGRAWAL S. , AGRAWAL B. K.
Published: May 2011

The stability, structural, electronic, and optical properties have been studied for most stable zinc sulfide nanoclusters Zn x S y (x + y = n = 2 to 4). A B3LYP-DFT/6-311G(3df) method is employed to optimize the geometries, and a TDDFT method is used for the study of the optical properties. The binding energies (BE), HOMO–LUMO gaps and the bond lengths have been obtained for all the clusters. We have considered also the zero point energy (ZPE) corrections ignored by the earlier workers. For a fixed value of n, we designate the most stable structure the one, which has maximum final binding energy per atom. The adiabatic and vertical ionization potentials (IP) and electron affinities (EA), charge on atoms, dipole moment, and optical properties have been investigated for the most stable structures. The nanoclusters containing large number of S atoms for each "n" are found to be most stable. Except for ZnS nanocluster, the HOMO–LUMO gap increases with the number of S atoms. Similarly, except for ZnS , IP and EA fluctuate with the cluster size but reveal downward trend. The optical absorption is quite weak in visible region but is strong in the ultraviolet region in most of the nanoclusters except a few. The growth of most stable nanoclusters may be possible in the experiments.
INSILICO MODELING AND SIMULATION OF MAGNETIC NANOPARTICLES FOR THE BIOLOGICAL CELL ISOLATION TECHNIQUE
Authors: GOPAL K. VARUN , NAMBOORI P. K. KRISHNAN , PREMKUMAR P. , GOPAKUMAR DEEPA , NARAYANAN B. SABARISH
Published: May 2011

Magnetic nanoparticles (MNPs) can be used in a wide variety of biomedical applications like contrast agents for magnetic resonance imaging, magnetic labeling, controlled drug release, hyperthermia, and in cell isolation. Most of these applications need distinct and controllable interactions between the MNPs and living cells and can be made possible by a proper functionalization technique. This paper describes a computational approach for the identification of magnetic nanoparticles for the development, design, and demonstration of a novel, incorporated system for selective and rapid removal of biological, chemical, and radioactive biohazards from human body.

The attraction between an external magnetic field and the MNPs facilitate separation of a wide variety of biological materials. This principle can be used for the isolation and aggregation of wandering cancer cells from the blood or the bone marrow to make a proper and early diagnosis of leukemia. Similarly, toxins, kidney stones, and other unwanted particles in the human body can be easily diagnosed and removed by the same technique.

Nanoparticle-sized iron oxides have been studied in this work by computational modeling and molecular dynamic (MD) simulation techniques. Structural, thermodynamic, and magnetic properties have been formulated. In this work, nanoparticles of size varying from 0.5 to 2.5 nm have been analyzed. Cell isolation ability of the nanoparticles has been compared based on the computational results.

MNPs are biologically activated and permitted to bind with the targeted cells through various pathways, thereby allowing certain cellular compartments to be specifically addressed. Once the cells are identified, the preferred cellular compartments can be magnetically isolated and removed with the help of an external magnetic field. Out of the iron oxides analyzed in this work, 1.1 nm Fe3O4 is found to be most interacting with leukemia protein. Hence, leukemia cells can be effectively targeted, separated, and removed using Fe3O4 of the suggested dimension.
INVESTIGATING BRIDGE-LIKE STRUCTURES IN A SQUARE-WELL BINARY MIXTURE USING NVT MONTE CARLO SIMULATION
Authors: SINGH SATYA PAL , SINGH JAYANT K. , SHARMA ASHUTOSH
Published: May 2011

Bridge-like structures have been reported in recent studies for a binary mixture with square well fluids in 2D and 3D using different techniques. In this paper, we present our NVT simulation results in 3D with symmetric additive water and oil-like molecules. We use Dirac's delta function defined using theta step function for evaluating pressure components and surface tension values. Our investigation reveals that though 3D NVT MC results are in qualitative agreement with the published results showing all the structures as bridge-like, complete wetting of the walls by the preferred component and micelle structures but the critical parameters as surface attraction strength significantly alter to lower values for PW and CW cases in comparison to the 2D MD cases. We have studied cases with pore width as H = 6.0, 8.0, and 10.0 at T = 0.70, 0.80, and 0.90 for εAB = 0.0, 0.25, 0.50, and 1.0. For all of the bridge cases ε Wall -A = -0.50 and λ wall -A = 1.0. For fluid–fluid interaction λ ff = 1.2 and 1.5 are taken with εAA = εBB = -1.0. Our pressure and surface tension values show clear signature of confinement effect and dependence on other parameters for the bridge cases but it is concluded that different structural transitions depend only on the predefined energetically favorable and unfavorable interfaces which in turn comes from the separation of the two walls and average initial density. Our density profiles confirm the evolved structures.
SURFACE EFFECTS ON THE VELOCITY OF DISLOCATIONS AT THE NANOSCALE
Authors: BHATTACHARYA M. , DUTTA A. , MUKHERJEE P. , GAYATHRI N. , DAS G. C. , BARAT P.
Published: May 2011

We have observed prominent change in the velocity of dislocation in thin films due to the proximity of free surfaces using molecular dynamics simulations. A simple model has been introduced and the numerical implementation of our model is in accord with the simulation results. Such surface effects have been attributed to the change in lattice resistance to dislocation motion.
STUDIES ON UV PHOTOLUMINESCENCE FROM PULSED LASER DEPOSITED ENSEMBLES OF CAPPED SILICON NANOPARTICLES
Authors: KUKREJA LALIT M. , CHATURVEDI AMITA , SINGH B. N. , DETTY A. P. , PILLAI V. P. M. , SARTOR J. , KALT H. , KLINGSHIRN C.
Published: May 2011

Multilayer ensembles of alumina capped, widely dispersed silicon nanoparticles ( Si -nps) with mean diameter in the range of about 1–4 nm were grown using pulsed laser deposition. With photo-excitation at ~3.82 eV, photoluminescence (PL) was found to emanate from these Si -nps mainly in the UV spectral region centered at about 3.37 eV due to the Γ25–Γ15 transitions. It was found that while the bandgap measured from photoabsorption spectra showed blueshift with decreasing mean size of the Si -nps, spectral position of the PL peaks remained almost insensitive to variation in the mean size. The PL peak at about 3.37 eV was observed to vanish at temperatures higher than 70 K and another one at about 3.31 eV attributed to the TO phonon replica disappeared above 100 K. In general FWHM of both these PL peaks was found to increase monotonically from about 6 to 19 meV and the peak positions were found to undergo redshift with increase in the sample temperature from 10 to 100 K. These observations could be explained by applying Bose statistics for a 6 meV confined phonon mode broadening of the Si -nps and using the Varshni equation, respectively. Si -nps grown in oxygen ambient at 600°C showed significant enhancement in the PL intensity with increasing pressure. These findings elicit that light emission from Si -nps is either due to the nanoparticles of about 1 nm and smaller size primarily driven by the quantum confinement or due to an interface state pumped by these Si -nps.
TNF-α converting enzyme-mediated ErbB4 transactivation by TNF promotes colonic epithelial cell survival
Authors: Hilliard Valda C. , Frey Mark R. , Dempsey Peter J. , Peek Richard M. , Polk D. Brent
Published: May 2011

Disruption of intestinal epithelial homeostasis, including enhanced apoptosis, is a hallmark of inflammatory bowel disease (IBD). We have recently shown that tumor necrosis factor (TNF) increases the kinase activity of ErbB4, a member of the epidermal growth factor receptor family that is elevated in mucosa of IBD patients and that promotes colon epithelial cell survival. In this study, we tested the hypothesis that TNF transactivates ErbB4 through TNF-α converting enzyme (TACE)-mediated ligand release and that this transactivation is necessary to protect colonic epithelial cells from cytokine-induced apoptosis. Using neutralizing antibodies, we show that heparin-binding EGF-like growth factor (HB-EGF) is required for ErbB4 phosphorylation in response to TNF. Pharmacological or genetic inhibition of the metalloprotease TACE, which mediates HB-EGF release from cells, blocked TNF-induced ErbB4 activation. MEK, but not Src or p38, was also required for transactivation. TACE activity and ligand binding were required for ErbB4-mediated antiapoptotic signaling; whereas mouse colon epithelial cells expressing ErbB4 were resistant to TNF-induced apoptosis, TACE inhibition or blockade of ErbB4 ligand binding reversed the survival advantage. We conclude that TNF transactivates ErbB4 through TACE-dependent HB-EGF release, thus protecting colon epithelial cells from cytokine-induced apoptosis. These findings have important implications for understanding how ErbB4 protects the colon from apoptosis-induced tissue injury in inflammatory conditions such as IBD.
Impact of exercise training on endothelial transcriptional profiles in healthy swine: a genome-wide microarray analysis
Authors: Padilla Jaume , Simmons Grant H. , Davis J. Wade , Whyte Jeffrey J. , Zderic Theodore W. , Hamilton Marc T. , Bowles Douglas K. , Laughlin M. Harold
Published: May 2011

While the salutary effects of exercise training on conduit artery endothelial cells have been reported in animals and humans with cardiovascular risk factors or disease, whether a healthy endothelium is alterable with exercise training is less certain. The purpose of this study was to evaluate the impact of exercise training on transcriptional profiles in normal endothelial cells using a genome-wide microarray analysis. Brachial and internal mammary endothelial gene expression was compared between a group of healthy pigs that exercise trained for 16–20 wk ( n = 8) and a group that remained sedentary ( n = 8). We found that a total of 130 genes were upregulated and 84 genes downregulated in brachial artery endothelial cells with exercise training (>1.5-fold and false discovery rate <15%). In contrast, a total of 113 genes were upregulated and 31 genes downregulated in internal mammary artery endothelial cells using the same criteria. Although there was an overlap of 66 genes (59 upregulated and 7 downregulated with exercise training) between the brachial and internal mammary arteries, the identified endothelial gene networks and biological processes influenced by exercise training were distinctly different between the brachial and internal mammary arteries. These data indicate that a healthy endothelium is indeed responsive to exercise training and support the concept that the influence of physical activity on endothelial gene expression is not homogenously distributed throughout the vasculature.