bluuebunny/crossref_metadata_2025 huggingface dataset:
Virological and Immunological Factors Associated with HIV-1 Differential Disease Progression in HLA-B*58:01-Positive Individuals
Authors: Chopera D. R. , Mlotshwa M. , Woodman Z. , Mlisana K. , de Assis Rosa D. , Martin D. P. , Abdool Karim S. , Gray C. M. , Williamson C. ,   the CAPRISA 002 Study Team
Published: May 2011

Molecular epidemiology studies have identified HLA-B*58:01 as a protective HIV allele. However, not all B*58:01-expressing persons exhibit slow HIV disease progression. We followed six HLA-B*58:01-positive, HIV subtype C-infected individuals for up to 31 months from the onset of infection and observed substantial variability in their clinical progression despite comparable total breadths of T cell responses. We therefore investigated additional immunological and virological factors that could explain their different disease trajectories. Cytotoxic T-lymphocyte (CTL) responses during acute infection predominantly targeted the TW10 and KF9 epitopes in p24
Gag
and Nef, respectively. Failure to target the TW10 epitope in one B*58:01-positive individual was associated with low CD4
+
counts and rapid disease progression. Among those targeting TW10, escape mutations arose within 2 to 15 weeks of infection. Rapid escape was associated with preexisting compensatory mutations in the transmitted viruses, which were present at a high frequency (69%) in the study population. At 1 year postinfection, B*58:01-positive individuals who targeted and developed escape mutations in the TW10 epitope (
n
= 5) retained significantly higher CD4
+
counts (
P
= 0.04), but not lower viral loads, than non-B*58:01-positive individuals (
n
= 17). The high population-level frequency of these compensatory mutations may be limiting the protective effect of the B*58:01 allele.
‘forbidden Points— in Pregnancy: No Plausible Mechanism for Risk
Authors: Cummings Mike
Published: May 2011

It has been suggested that acupuncture may pose particular risks during pregnancy: by enhancing oxygenation to the developing embryo (presumably via increasing blood flow to the uterus); by affecting the level of maternal progesterone in early pregnancy; or by stimulating uterine contractions. This article examines the proposed risks and fails to find any plausible physiological mechanism for them.
Justification for a home-based education programme for kidney patients and their social network prior to initiation of renal replacement therapy
Authors: Massey Emma K , Hilhorst Medard T , Nette Robert W , Smak Gregoor Peter J H , van den Dorpel Marinus A , van Kooij Anthony C , Zuidema Willij C , Zietse R , Busschbach Jan J V , Weimar Willem
Published: May 2011

In this article, an ethical analysis of an educational programme on renal replacement therapy options for patients and their social network is presented. The two main spearheads of this approach are: (1) offering an educational programme on all renal replacement therapy options ahead of treatment requirement and (2) a home-based approach involving the family and friends of the patient. Arguments are offered for the ethical justification of this approach by considering the viewpoint of the various stakeholders involved. Finally, reflecting on these ethical considerations, essential conditions for carrying out such a programme are outlined. The goal is to develop an ethically justified and responsible educational programme.
Attitudes towards the extension of smoking restrictions to selected outdoor areas in Italy
Authors: Gallus Silvano , Rosato Valentina , Zuccaro Piergiorgio , Pacifici Roberta , Colombo Paolo , Manzari Marco , La Vecchia Carlo
Published: May 2011

Objectives

To estimate the attitudes of Italians on the extension of the smoking ban to selected public outdoor areas.

Methods

The authors considered data from two Italian surveys on smoking conducted in 2009 and 2010 on a total sample of 6233 individuals, representative of the Italian population aged 15 years or over.

Results

64.6% of Italians supported smoke-free policies in public parks, 68.5% in sports stadiums, 62.1% in beaches, 85.9% in school courtyards and 79.9% in outdoor areas surrounding hospitals. Among current smokers, the corresponding estimates were 32.9% for parks, 38.2% for stadiums, 31.2% for beaches, 67.6% for schools and 55.3% for hospitals.

Conclusions

Extension of the smoking ban to selected outdoor areas is supported by the large majority of the Italian population. The overwhelming majority of support for smoke-free school grounds and outdoor areas surrounding hospitals indicates that legislative action is required.
Relationships between habitat characteristics and breeding population densities in sockeye salmon (Oncorhynchus nerka)
Authors: Braun Douglas C. , Reynolds John D.
Published: May 2011

We examine the importance of stream habitat characteristics in governing variation in spawning densities of sockeye salmon ( Oncorhynchus nerka ) across 32 streams in the Fraser River Basin, British Columbia, Canada. We used mixed-effects models to examine four competing hypotheses for the influence of abiotic stream characteristics acting on either adult salmon or embryo mortality. All models that received support using Akaike’s information criterion included stream characteristics that are associated with cover. These included the percent area of pools, percentage of the banks that were undercut, and large woody debris (in that order). These results suggest the importance of stream characteristics, which reduce risk of predation on adults, in determining spawning sockeye salmon densities. Thus, identification of a small number of physical characteristics of streams provides insight into ecological processes that determine population densities. This information can be used to quantify habitat quality, which can guide habitat prioritization for conservation.
Changed cycling of P, N, Si, and DOC in Danish Lake Nordborg after aluminum treatment
Authors: Egemose Sara , de Vicente Inmaculada , Reitzel Kasper , Flindt Mogens R. , Andersen Frede Ø. , Lauridsen Torben L. , Søndergaard Martin , Jeppesen Erik , Jensen Henning S.
Published: May 2011

Loading, retention, and in-lake cycling of phosphorus (P), nitrogen, silica, and dissolved organic carbon (DOC) were studied 1 year before and 3 years after P-inactivation by aluminum (Al) hydroxide in Danish Lake Nordborg in 2006. Simultaneously, external P loading was reduced by 40% via establishment of precipitation ponds in two inlets. After Al treatment, the internal P loading (sediment P release) during summer declined 90%–94%, owing to adsorption to aluminum hydroxide. Also, silicate regeneration from the sediment was reduced by 69%–76%, and sediment oxygen uptake as well as ammonium release declined markedly. Consequently, lake water total P, dissolved inorganic P, silicate, and DOC decreased by 73%, 97%, 87%, and 46%, respectively. The Secchi depth increased in the summer period during the first post-treatment year, but declined afterwards to pre-treatment levels, even though the mean lake-water total P concentration during summer was reduced from ∼240 µg·L–1before treatment to 26–65 µg·L–1in the first three post-treatment years. We conclude that a further reduction in external P loading is needed to obtain the full effect of the Al treatment in Lake Nordborg.
Confidence intervals for trawlable abundance from stratified-random bottom trawl surveys
Authors: Cadigan Noel G.
Published: May 2011

A basic objective of most trawl surveys is to estimate average fish density and account for uncertainty in the estimation. This is of increasing relevance because of the desire to better reflect uncertainty about stock status in fisheries management decisions. I develop score-statistic confidence intervals based on the common stratum area-weighted average estimator for stock abundance based on catches from stratified-random bottom trawl surveys and on the assumption that variation in survey catches is negative binomial in form. These confidence intervals cover only positive values and have improved coverage accuracy compared with standard-t or bootstrap intervals that are commonly used for this type of data. Methods are applied to six case studies, and simulations based on these case studies are used to evaluate the accuracy of the confidence intervals.
THEORETICAL ANALYSIS OF COEXISTING TETRAGONAL AND RHOMBOHEDRAL PHASE IN PB(ZR0.35TI0.65)O3 FILMS
Authors: CHEN QINGDONG , LI XINZHONG , LI LIBEN , YOU JINGHAN , ZHU JINSONG
Published: May 2011

Within the framework of Pertsev's thermodynamic theory, the equilibrium polarization states and the physical properties of single-domain Pb ( Zr 0.35 Ti 0.65) O 3 (PZT) thin films epitaxially grown on dissimilar cubic substrates are investigated. The "misfit strain-temperature" phase diagrams are obtained for the films. The presence of stability range of the rhombohedral phase is the characteristic feature of these phase diagrams, which separates the stability ranges of the tetragonal phase and the orthorhombic phase. The coexistence of the rhombohedral phase and the tetragonal phase in PZT film can be explained by Pertsev's theory with the gradient strain case with a suitable stress form.
THEORY OF ORBITAL MAGNETIZATION IN SOLIDS
Authors: THONHAUSER T.
Published: May 2011

In this review article, we survey the relatively new theory of orbital magnetization in solids — often referred to as the "modern theory of orbital magnetization" — and its applications. Surprisingly, while the calculation of the orbital magnetization in finite systems such as atoms and molecules is straight forward, in extended systems or solids it has long eluded calculations owing to the fact that the position operator is ill-defined in such a context. Approaches that overcome this problem were first developed in 2005 and in the first part of this review we present the main ideas reaching from a Wannier function approach to semi-classical and finite-temperature formalisms. In the second part, we describe practical aspects of calculating the orbital magnetization, such as taking k-space derivatives, a formalism for pseudopotentials, a single k-point derivation, a Wannier interpolation scheme, and DFT specific aspects. We then show results of recent calculations on Fe, Co, and Ni. In the last part of this review, we focus on direct applications of the orbital magnetization. In particular, we will review how properties such as the nuclear magnetic resonance shielding tensor and the electron paramagnetic resonance g-tensor can be elegantly calculated in terms of a derivative of the orbital magnetization.
EFFECT OF SWIFT HEAVY ION IRRADIATION ON THE STRUCTURAL AND MORPHOLOGICAL ASPECTS OF COPPER FERRITE NANOPARTICLES
Authors: BALAJI M. , PADIYAN D. PATHINETTAM , RAJA M. MANIVEL , ASOKAN K. , KANJILAL D.
Published: May 2011

Influence of Ni 11+ swift heavy ion (SHI) irradiation induced modifications on structural and morphological aspects of CuFe 2 O 4 nanoparticles have been studied. The bulk sample is synthesized using co-precipitation technique. The cubic spinel structure is identified using X-ray diffraction technique and these nanoparticles have an average grain size of about 10 nm. These materials are irradiated at various fluences of 1 × 1011, 1 × 1012, 1 × 1013, 1 × 1014, and 5 × 1014 ions/cm 2 using Ni 11+ ion beam of 150 MeV energy. The XRD pattern of the irradiated material shows the change in crystalline nature. The spinel ferrite (311) peak, which is having maximum intensity in the pristine, decreases at the fluence of 1 × 1011 and 1 × 1012 ions/cm 2 and then completely vanishes on further irradiation. However, a new X-ray peak arises in the (222) direction. All the other peaks in the pristine sample vanish on irradiation elucidating the creation of amorphization nature. Scanning electron microscope (SEM) analysis shows fine blocks of material for pristine and partial agglomeration on irradiation. Notably, a large number of holes are present at the fluence of 5 × 1014 ions/cm 2 due to heavy ion irradiation. The phase change from crystalline to amorphous nature on XRD and the creation of holes from SEM is discussed on the basis of electrophonon coupling and it invokes the thermal spike theory.
SWIFT HEAVY ION IRRADIATION: A NOVEL TECHNIQUE FOR TAILORING THE SIZE OF POLYANILINE NANOFIBERS
Authors: KUMAR A. , BANERJEE SOMIK
Published: May 2011

Swift heavy ion (SHI) (energy > 1 MeV/u) irradiation of polymer nanostructures is a novel technique to tailor their structure and properties. Polyaniline nanofibers synthesized by interfacial polymerization using HCl and camphor sulfonic acid (CSA) as dopants have been irradiated with 90 MeV O 7+ ion at different fluences of 3 × 1010, 3 × 1011, and 1 × 1012 ions/cm2. TEM micrographs of the irradiated nanofibers reveal a gradual decrease in the size of the nanofibers with an increase in fluence, which could be attributed to the strain-induced fragmentation upon SHI irradiation. The generation of strain in the PAni nanofibers upon SHI irradiation can be explained on the basis of the Coulomb explosion model. X-ray diffraction analysis for both the HCl and CSA-doped nanofibers shows broadening of the peak at 2θ = 20.050, which can be attributed to the reduced domain length and enhanced strain in the material. The two contributions have been separated out. The samples have been characterized with microRaman spectroscopy, which shows a decrease in the intensity of the Raman active modes that can be attributed to the reduction in size of the nanofibers leading to the amorphization of the material.
FORMATION OF ONE-DIMENSIONAL Ga STRUCTURES ON Si(5 5 12)-2 × 1 TRENCHED TEMPLATES
Authors: KUMAR PRAVEEN , KUMAR MAHESH , GOVIND  , MEHTA B. R. , SHIVAPRASAD S. M.
Published: May 2011

In the advent of GaN photonic devices, there is renewed interest in looking at the growth of nanostructures of III-Nitrides that can yield novel properties. To grow a high density of self-assembled GaN nanostructures on a large scale, there is a need to use templates with well-defined nanometer scale features. The Si (5 5 12)-2 × 1 surface is a naturally faceted stable surface that has several nanotrenches of (225) and (337) with a large unit cell of 5.35 × 0.77 nm2. In this work we present here, the first report on the X-ray photoelectron spectroscopy study of the adsorption kinetics of Ga on Si (5 5 12)-2 × 1 reconstructed surface. The uptake curve which is the plot of the ratio of Ga (2 p ) to Si (2 p ) intensity with deposition time, shows that Ga grows in a Stranski–Krastnov growth mode on Si (5 5 12) surface. The core level spectra of Si (2 p ) and Ga (2 p ) have been deconvoluted to see the evolution of the interface during the adsorption process of Ga . The valence-band spectra show the modification of the electronic structure and the secondary electron emission spectra yield the change in work function during Ga adsorption. Correlating the electronic and structural aspects of the interface formation results the study demonstrates the possibility of integrating Si and group III-nitride technologies while exploiting the novel properties due to reduced dimensions.
EFFECT OF RAPID THERMAL ANNEALING ON MICROSTRUCTURE AND OPTICAL PROPERTIES OF ZnO NANORODS
Authors: CHAKRABORTY R. , DHARA SOUMEN , GIRI P. K.
Published: May 2011

In this work, we have investigated the influence of rapid thermal annealing (RTA) on structural and optical properties of ZnO nanorods synthesized by a mechanochemical reaction route using a planetary ball mill for different reaction time durations. Optical properties of as-grown and RTA-annealed samples are studied by UV–visible absorption and photoluminescence (PL), while structural studies are performed using X-ray diffraction line profile analysis and transmission electron microscopy. X-ray diffraction pattern of each sample is accompanied by characteristic wurtzite peaks of zinc oxide and exhibits the decrease in full width half maxima of the peaks after RTA. Williamson–Hall plot of each pattern is done to correlate the effect of strain of as-synthesized and RTA-treated samples. UV–visible absorption spectra show distinct redshift of excitonic absorption peaks with respect to those of as-synthesized samples. Interestingly, in PL spectra, the broad visible emission peaks observed for as-synthesized samples are eliminated completely for annealed samples. However, some of the constituent peaks in the UV–blue region of the PL spectra redshifted due to the grain growth and strain reduction.
CHARACTERIZATION AND ELECTRICAL PROPERTIES OF ALIGNED CARBON NANOTUBES WITH HIGH ASPECT RATIO
Authors: BHATIA RAVI , PRASAD V. , REGHU M.
Published: May 2011

High-quality multiwall carbon nanotubes (MWNTs) were produced by a simple one-step technique. The production of MWNTs was based on thermal decomposition of the mixture of a liquid phase organic compound and ferrocene. High degree of alignment was noticed by scanning electron microscopy. The aspect ratio of as-synthesized MWNTs was quite high (more than 4500). Transmission electron microscopy analysis showed the presence of the catalytic iron nanorods at various lengths of MWNTs. Raman spectroscopy was used to know the quality of MWNTs. The ratio of intensity of the G-peak to the D-peak was very high which revealed high quality of MWNTs. Magnetotransport studies were carried out at low temperature and a negative MR was noticed.
DUMBBELL-SHAPED ZnO NANORODS: GROWTH AND CHARACTERIZATION
Authors: RAJKUMAR N. , PRABHU M. , RAMACHANDRAN K.
Published: May 2011

A novel one-step method to synthesize large-scale uniform dumbbell-shaped ZnO nanorods is presented here. The structural morphology was investigated by using X-ray diffraction, scanning electron microscopy, and high-resolution transmission electron microscopy analyses. The prepared dumbbells with diameter of 300 nm and length of 1.5 μm possess hexagonal structure with preferable [001] growth direction. The UV–vis absorption spectra show blueshift for smaller nanoparticles and redshift for bigger dumbbell-shaped ZnO nanorods.
SWIFT HEAVY ION INDUCED NANOHILL FORMATION ON THE SURFACE OF GaP
Authors: DUBEY R. L. , DUBEY S. K. , YADAV A. D. , KANJILAL D.
Published: May 2011

Gallium phosphide ( GaP ) samples were irradiated with swift (100 MeV)56 Fe 9+ ions for various ion fluences varying from 1 × 1011 to 1 × 1014 cm -2. Atomic force microscopy, Raman scattering, and X-ray diffraction techniques have been used to investigate the irradiation effect. Atomic force microscopy studies showed the presence of nanosized hills separated with valleys at the surface of irradiated gallium phosphide. The average diameters of hills were found to be 19.76, 19.81, 20.70, and 22.64 nm for ion fluences 5 × 1012, 1 × 1013, 5 × 1013, and 1 × 1014 cm -2, respectively. Root mean square surface roughness analysis has been used to characterize the nature of the surface under swift heavy ion irradiation. The features observed in the Raman spectra at 402.18 cm-1 and 365.05 cm-1 were assigned to the characteristic first-order longitudinal optical (LO) phonon mode and transverse optical (TO) phonon mode of gallium phosphide, respectively. We have also observed the second-order overtones and combinations of optical modes giving rise to three characteristic peaks in the region between 700 and 800 cm-1. X-ray diffraction technique has been used to determine the crystallite size. The crystallite size was found to decrease with increase in ion fluence.
ULTRAFAST HEAT DISSIPATION DYNAMICS OF SILVER NANOPARTICLES
Authors: PAL S. P. , SEN P.
Published: May 2011

Time-resolved fluorescence spectroscopy has been employed to study the ultrafast heat dissipation dynamics of silver nanoparticles dispersed in methanol, tetrahydrofuran, and hexane. The average relaxation time obtained is in the order of several hundreds of picoseconds indicating lack of band-edge emission where lack of scaling of these times with the thermal conductivity of the surrounding medium indicate disparate heat dissipation pathways.
CONTROLLED GROWTH OF SEMICONDUCTING SINGLE-WALL CARBON NANOTUBE
Authors: ROY SOUMYENDU , BAJPAI REETI , HAZRA K. S. , RAI PADMNABH , KULSRESTHA N. , MISRA D. S.
Published: May 2011

SWCNT was synthesized by catalytic thermal CVD using Fe–Mo and Co–Mo bimetallic catalysts supported by MgO . The nanotubes were studied by SEM and HRTEM microscopy, thermogravimetric analysis, and Raman spectroscopy. The chiralities of the tubes were established from their Raman spectra using Kataura plot. The Raman shifts for the Co-catalyzed nanotubes were found to lie in the semiconducting region.
STRUCTURAL TRANSITION OF NANOCRYSTALLINE TiO2
Authors: KAR MANORANJAN , RAMA KRISHNAN N. , TALUKDAR INDRAJIT , ACHARYYA K.
Published: May 2011

Nanocrystalline TiO 2 sample was prepared by high-energy ball mill method. A known quantity of anatase phase- TiO 2 was milled for 83 h in air. The samples were collected at intervals of 5 h of milling. The XRD patterns were recorded for all the samples. The crystal structure changed from anatase phase for bulk material to rutile-rich phase for nanocrystalline material. Nanocrystalline TiO 2, which is a mixture of anatase, rutile, and srilankite phase, was prepared by milling for 60 h. The XRD pattern of unmilled anatase phase of TiO 2 could be refined with I41/amd space group. The crystallite size of the TiO 2 was found to decrease with milling time upto 50 h and then the size of rutile phase increases while the sizes of anatase and srilankite phases remain constant upto 60 h of milling. After 60 h, the sizes of all the phases remain constant. The average crystallite size for rutile phase is found to be 12 nm after 60 h of milling.
GROWTH OF PERCOLATED Ag NANOSTRUCTURES ON Si(111)-(7 × 7) SURFACES
Authors: GOSWAMI D. K. , PAL A.
Published: May 2011

Growth of Ag nanostructures on Si (111)-7 × 7 surfaces has been investigated at the atomic scale regime by studying the evolution of nanoscale surface morphology with Ag coverage. Ag growth on Si (111)-7 × 7 surfaces at room temperature showed a strongly preferential height with even atomic layer thick flat top percolated islands. Here we report that the roughness scaling exponent α and growth scaling exponents β associated with such electronic growth mode are determined by statistical analysis of rough surfaces obtained from scanning tunneling micrograph images of Ag nanostructures grown on Si (111)-7 × 7 surfaces. Observed roughness and growth exponent for this system are 0.82±0.02 and 0.45±0.04, respectively.
GROWTH OF Si ATOMIC WIRES ON Pb-MEDIATED Si(111)7 × 7 SUBSTRATE
Authors: CHATTERJEE K. , CHANG T.-C. , CHANG S.-H. , HONG I. PO , HWANG I.-S.
Published: May 2011

The growth of the self-assembled Si atomic wires on Pb -covered Si (111) 7 × 7 substrate has been studied using homemade scanning tunneling microscope (STM) at room temperature (RT). These surfactant-mediated epitaxially grown Si atomic wires ( SiAWs ) are quite stable at RT. It is interesting that they always appear in pairs having a distance of ~9 Å in between them. They have only three special growth directions, parallel to the three possible crystal directions of the Si (111) substrate underneath. The SiAW can be imaged down to few mV bias voltages, and the voltage current characteristic investigated with scanning tunneling spectroscopy reveals metallic electronic structure of this special kind of SiAW .
ROOM TEMPERATURE FERROMAGNETISM IN Co-DOPED ZnO NANOPARTICLES: MILLING TIME DEPENDENCE AND ANNEALING EFFECT
Authors: PAL BAPPADITYA , GIRI P. K.
Published: May 2011

We report on the occurrence of room temperature ferromagnetism in Co -doped ZnO nanoparticles (NPs). Doping is performed by ball milling of 3 wt% of Co mixed with ZnO nanopowders (commercial) for durations of 2–8 h. X-ray diffraction data and high-resolution transmission electron microscopy (HRTEM) confirm the absence of metallic Co clusters or any other phase different from würtzite-type ZnO . The magnetization (M–H curve) measured at room temperature exhibits the clear ferromagnetic characteristic with saturation magnetization (Ms) and coercive field (Hc) of the order of 3–4 emu/g and 225 Oe, respectively. Post-growth annealing at 250°C results in an increase of Ms by a small magnitude, while annealing at 500°C results in reduction of Ms. UV–visible absorption spectra show small redshift in the absorption peaks in the Co -doped ZnO NPs due to the incorporation of Co atoms in ZnO lattice. Room temperature photoluminescence studies show enhanced near-band-edge emission at 378 nm in the doped NPs as compared to the undoped NPs indicating low density of defects in the doped ZnO crystals. Contribution of intrinsic defects and magnetic impurities in the observed ferromagnetism is discussed.
ELECTRONIC PROPERTIES OF GRAPHENE, FEW-LAYER GRAPHENE, AND BULK GRAPHITE UNDER VERY HIGH MAGNETIC FIELD
Authors: KUMAR AMIT , POUMIROL J. M. , ESCOFFIER W. , GOIRAN M. , RAQUET B. , BROTO J. M.
Published: May 2011

In the present work, we report on the magneto-transport properties of graphitic based materials (graphene, few-layer graphene, and bulk graphite) in very high magnetic field. Quantum Hall Effect (QHE) has been studied in graphitic systems in very high pulsed magnetic field (up to B = 57 T ) and at low temperature (≤ 4 K). Graphene sample shows well-defined Hall resistance plateaus at filling factors v = 2,6,10, etc. Few-layer graphene systems display clear signatures of standard and unconventional QHE. Magneto-transport studies on bulk highly oriented pyrolytic graphite show a charge density wave transition at strong enough magnetic field as well as Hall coefficient sign reversal.
NONLINEAR OPTICAL PROPERTIES OF DOPED ZnS QUANTUM DOTS
Authors: KUMBHAKAR P. , CHATTOPADHYAY M. , MITRA A. K.
Published: May 2011

Three- and four-photon nonlinear absorptions are reported by z-scan techniques in ZnS and 1% Mn 2+ doped ZnS quantum dots (QDs) with 532 and 1064 nm radiations, respectively, obtained from a Q-switched Nd :YAG laser fundamental and its second harmonic radiation. The obtained maximum value of the 3PA coefficient in the doped ZnS QDs is ~105 times that of bulk ZnS . Also, intensity-dependent saturation of 3PA has been observed and the measured experimental data are explained theoretically using a 3PA saturation model and the characteristic saturation intensity is estimated to be 0.92±0.04 GW/cm2.
PHOTOLUMINESCENCE OF ZINC OXIDE INVERSE PHOTONIC CRYSTAL
Authors: KEDIA SUNITA , VIJAYA R.
Published: May 2011

Three-dimensional photonic crystals prepared by self-assembly method from polymethyl methacrylate colloids are infiltrated with zinc oxide ( ZnO ) prepared using sol–gel technique. The polymer template is removed by chemical method and heat treatment to obtain inverse photonic crystals of ZnO . The inverse crystal fabricated by the chemical method is further heated at high temperature and the X-ray diffraction establishes the presence of single-crystalline ZnO . The photoluminescence is recorded from the inverse photonic crystals by exciting them with He–Cd laser at 325 nm. The as-prepared inverse crystals show only UV emission while the inverse crystal obtained by the chemical route and treated at high temperature shows the visible emission due to oxygen vacancy defects.
NANO-GOLD AND NANO-ZINC OXIDE: EFFECT ON GUSTATORY RECEPTOR GENES IN FLIES
Authors: DAS SUMISTHA , DEBNATH NITAI , BRAHMACHARY R. L. , CHANDRA RAMESH , ROY BISWAJIT , GOSWAMI ARUNAVA
Published: May 2011

Drinking colloidal gold as elixir of life is an age-old practice worldwide. A large body of data containing patients' experiences after intake of colloidal gold for long duration would be available in the medical records of hospitals. ZnO has been approved by FDA for topical use and not for oral intake. Drosophila melanogaster (wild type) strains were fed with physiologically relevant concentrations of nano-gold and nano- ZnO along with appropriate controls. Citrate-capped nano-gold (average particle size is 15–20 nm) synthesized by reducing hydrogen tetrachloroaurate with 1% trisodium citrate and custom-made nano- ZnO , purchased from M K Implex, Canada (average particle size 50 nm) were used as treatments. Microarray studies revealed that fly trehalose receptor genes, Tre and Tre1, are both unaffected after nano-gold and nano- ZnO treatment. Gr64 subfamily members (encoding sugar receptors like glucose, sucrose, and maltose), for example, Gr64a-b become downregulated, but Gr64c, Gr64d, Gr64f remain unaltered in case of both the treatments. Among bitter receptor genes, Gr66a is the most well studied and shows significant downregulation by nano-gold and not by nano- ZnO . Ppk11 and Ppk19 are gustatory ion channel genes which modulate salt perception. Ppk11 was found to be downregulated by both nano-gold and nano- ZnO , while ppk19 expression is suppressed by nano-gold treatment but not by nano- ZnO . The effects of these two nanoparticles on pheromone receptors (Gr32a, Gr39a, and Gr68a) and CO 2 receptors (Gr21a and Gr63a) are presented. To the best of our knowledge, this is the first report on the effect of pure nanoparticles on gustation. Data has been analyzed in the light of the age-old tradition of oral administration of the nano-gold viz-a-viz topical use of nano- ZnO . These results would have far reaching implications in the design of nano-gold mediated oral drug delivery of cancer and other drugs as well as nano- ZnO coated drugs/cosmetics and nano- ZnO carrier based drug delivery in skins and in other topical applications.
PRODUCTION OF HERBAL-BASED NANOPARTICLES FOR MEDICAL TEXTILES
Authors: RAJENDRAN R. , RADHAI R. , MAITHILI N. , BALAKUMAR C.
Published: May 2011

The use of materials created through nanotechnology is expected to dramatically increase over the next few years. Nanotechnology can provide high durability for fabrics because nanoparticles have a large surface area to volume ratio and high surface energy, thus presenting better affinity for fabrics, leading to an increase in durability of the function. In this study herbal plants such as Curcuma longa and Datura metel were selected, and bioactive compounds were extracted and standardized. Nanoparticles of the medicinal plant extracts were prepared by coacervation method using bovine serum albumin, cross-linked with gluteraldehyde and finished on 100% pure cotton by pad-dry-cure method. The antimicrobial activities of the nanoparticles-treated cotton fabrics were found to be higher than that of the control fabrics in both AATCC 147 and Hohestein Challenge test.
AMIDE FUNCTIONALIZATION OF MULTIWALLED CARBON NANOTUBES AND THEIR EVALUATION FOR Hg(II) REMOVAL FROM WATER
Authors: MISRA R. K. , JAIN S. K. , ABRAHAM THOMAS N. , KHATRI P. K.
Published: May 2011

This paper deals with the amide functionalization of multiwalled carbon nanotubes (MWNTs) and its evaluation for mercury removal from water. The functionalized MWNTs were characterized using FTIR for structural modification. The properties of MWNTs such as hydrophilic character, nature of surface, selective chemical interaction with mercury, etc., were significantly improved after functionalization making them promising adsorbents for mercury removal. The equilibrium is achieved in short time of 5 h resulting in up to 80% removal of Hg (II). Kinetics of adsorption was established and found to follow first-order reversible kinetics with forward and backward reaction rate constants 0.6648 and 0.1662, respectively.
HUMIDITY SENSOR USING NIPAAm NANOGEL AS SENSING MEDIUM IN SAW DEVICES
Authors: RAMAKRISHNAN N. , VAMSI TALLA , KHAN ASLAM , NEMADE HARSHAL B. , PALATHINKAL ROY PAILY
Published: May 2011

In this paper we report poly N-isopropylacrylamide (NIPAAm) nanogel used as sensing medium in Rayleigh wave type surface acoustic wave (SAW) devices to measure relative humidity. NIPAAm is synthesized by single-step surfactant-free emulsion polymerization reaction method. The prepared nanogel particles have dimensions less than 180 nm. Dynamic light scattering (DLS) analysis of these particles shows increase in size of the particles up to 100% when dispersed in water at room temperature. In this work we have developed two types of relative humidity (RH) sensors. In the first type commercial SAW resonators with resonance frequency at 315 MHz from EPCOSTM were used in our experiment. The casings of two resonators were removed carefully and one of them was left as such to serve as the reference device. The other was coated with the NIPAAm nanogel and used as the sensor. In the second type of SAW-based humidity sensor aluminum interdigital transducers (IDT) are fabricated over YZ lithium niobate piezoelectric substrate using metallization and lithography techniques. The fabricated IDTs have the pitch length of 34 μm and a resonance frequency of 51.6 MHz. Response of sensor to RH is measured by measuring the scattering parameters of both the types of sensors and reference devices recorded using the network analyzer.
POST-DEPOSITION ANNEALING INFLUENCED STRUCTURAL AND OPTICAL PROPERTIES OF RF MAGNETRON SPUTTERED TiO2 FILMS
Authors: UTHANNA S. , KONDAIAH P. , SEKHAR M. CHANDRA , REDDY R. SUBBA , RAO G. MOHAN
Published: May 2011

Titanium oxide films were deposited on Si and quartz substrates by RF magnetron sputtering of titanium target under various oxygen partial pressures. The films were annealed in air at different temperatures and the influence of annealing temperature on the structural and optical properties was studied. The XPS studies revealed that the films formed at oxygen partial pressure of 2 × 10-2 Pa were nearly stoichiometric. The as-deposited films were amorphous, the films annealed at 573 K were anatase, while those annealed at 973 K were mixed anatase and rutile phases of TiO 2. The as-deposited films showed an optical bandgap of 3.32 eV while those annealed at 973 K was 3.19 eV.
MAGNETOCALORIC EFFECT IN NANOCRYSTALLINE La0.67Ca0.33Mn0.9V0.1O3
Authors: NISHA P. , SURESH K. G. , VARMA MANOJ RAAMA
Published: May 2011

Vanadium-substituted La0.67Ca0.33MnO3 is synthesized fully in phase pure and nanocrystalline form for the first time, using nebulized spray pyrolysis. Highly uniform nanoparticles of average size in the range of 31–40 nm as revealed by XRD and TEM studies have been prepared. Rietveld refinement of XRD patterns shows small changes in lattice parameter compared to the parent compound La0.67Ca0.33MnO3 . The transition from ferromagnetic to paramagnetic state takes place over a broad temperature range, which can be attributed to the substitution of V at Mn sites as well as the nanometer size of the particles. Peak magnetic entropy change of these nanopowders was estimated to be about 4.5 J/kgK for a magnetic field of 5 T at 255 K. Compared to the bulk La0.67Ca0.33Mn0.9V0.1O3 , the entropy change of the nanoparticles is found to be smaller.
FREQUENCY-DEPENDENT POLARIZABILITY OF SMALL SILICON CLUSTERS
Authors: MAKWANI DIKSHA , VIJAYA R.
Published: May 2011

Polarizability of small Si n (n = 3 to 9) clusters has been calculated using density functional theory (DFT) with Vosko–Wilk–Nusair (VWN) correlation functional. The computed values of polarizability per atom tend to decrease with increasing cluster size. Frequency-dependent polarizability of Si 3, Si 4, Si 6, and Si 9 clusters demonstrates that the polarizability increases slowly with the increase in the energy for energy values less than 1.2 eV but exhibit the same size-dependent features as the static polarizability. The first resonance energy for Si 3, Si 4, Si 6, and Si 9 clusters occur at 1.25, 1.63, 2.5, and 1.98 eV, respectively. Moreover, the anisotropic polarizability is found to be the highest for Si 9 cluster.
A COMPARATIVE STUDY OF OPTICAL PROPERTIES OF C3N AND CN3 SYSTEMS THROUGH DENSITY FUNCTIONAL THEORY (DFT)
Authors: JANA DEBNARAYAN , CHEN LI-CHYONG , CHEN CHUN WEI , CHEN KUEI-HSIEN
Published: May 2011

The optical properties of (8,0) single wall carbon nanotubes (SWCNTs) alloyed with nitrogen ( N ) are computed using ab initio density functional theory (DFT). Both the real as well as imaginary dielectric constant in the long wavelength limit depends essentially on the nature of electromagnetic field. It is observed that for CN 3 systems, the reflectivity vanishes at 3.45, 6.95, and 8.20 eV, respectively for parallel, perpendicular polarization, and unpolarized light with incidence (1,0,0), while for C 3 N the vanishing reflectivity occurs only for parallel polarization at 8.05 eV. Although the magnitude of the significant peaks of loss function of CN 3 systems are comparable to C 3 N in perpendicular and unpolarized situation, however, they are significantly one order of magnitude higher in CN 3 for parallel polarization.
CRITICAL THICKNESS FOR Nb NANOFILM ON SAPPHIRE SUBSTRATE: AN EXAMPLE TOWARD UNDERSTANDING EVOLUTION OF COHERENT NANOSTRUCTURES
Authors: KUMAR ARUN , SUBRAMANIAM ANANDH
Published: May 2011

On growth beyond critical thickness, interfacial misfit dislocations partially relax the misfit strains in epitaxially grown nanofilms. In this study the stress state and growth of nanofilms are simulated using Finite Element Method (FEM) by imposing stress-free strains, corresponding to the lattice mismatch between Nb nanofilm and Sapphire substrate. On growth of the Nb nanofilm, a triangular network of edge misfit dislocations nucleates at the (0001) Al 2 O 3∥(111) Nb interface. Using a combined simulation of a coherently strained nanofilm and an edge dislocation, the critical thickness for the nucleation of an edge dislocation is determined using an equilibrium energy criterion. Theoretical analyses in literature use only the component of the Burgers vector parallel to the interface, which is an erroneous description of the stress state and energetics of the system. In this investigation the full interfacial edge dislocation is simulated using standard commercially available software and comparisons are made with results available in literature to bring out the utility of the methodology.
Hypertonic stress induces rapid and widespread protein damage in C. elegans
Authors: Burkewitz Kris , Choe Keith , Strange Kevin
Published: May 2011

Proteostasis is defined as the homeostatic mechanisms that maintain the function of all cytoplasmic proteins. We recently demonstrated that the capacity of the proteostasis network is a critical factor that defines the limits of cellular and organismal survival in hypertonic environments. The current studies were performed to determine the extent of protein damage induced by cellular water loss. Using worm strains expressing fluorescently tagged foreign and endogenous proteins and proteins with temperature-sensitive point mutations, we demonstrate that hypertonic stress causes aggregation and misfolding of diverse proteins in multiple cell types. Protein damage is rapid. Aggregation of a polyglutamine yellow fluorescent protein reporter is observable with <1 h of hypertonic stress, and aggregate volume doubles approximately every 10 min. Aggregate formation is irreversible and occurs after as little as 10 min of exposure to hypertonic conditions. To determine whether endogenous proteins are aggregated by hypertonic stress, we quantified the relative amount of total cellular protein present in detergent-insoluble extracts. Exposure for 4 h to 400 mM or 500 mM NaCl induced a 55–120% increase in endogenous protein aggregation. Inhibition of insulin signaling or acclimation to mild hypertonic stress increased survival under extreme hypertonic conditions and prevented aggregation of endogenous proteins. Our results demonstrate that hypertonic stress causes widespread and dramatic protein damage and that cells have a significant capacity to remodel the network of proteins that function to maintain proteostasis. These findings have important implications for understanding how cells cope with hypertonic stress and other protein-damaging stressors.
Reconstitution of lysosomal NAADP-TRP-ML1 signaling pathway and its function in TRP-ML1−/− cells
Authors: Zhang Fan , Xu Ming , Han Wei-Qing , Li Pin-Lan
Published: May 2011

It is well known that the mutation of TRP-ML1 (transient receptor potential-mucolipin-1) causes mucolipidosis IV, a lysosomal storage disease. Given that lysosomal nicotinic acid adenine dinucleotide phosphate (NAADP)-Ca2+ release channel activity is associated with TRP-ML1, the present study was designed to test the hypothesis that NAADP regulates lysosome function via activation of TRP-ML1 channel activity. Using lysosomal preparations from wild-type (TRP-ML1+/+) human fibroblasts, channel reconstitution experiments demonstrated that NAADP (0.01–1.0 μM) produced a concentration-dependent increase in TRP-ML1 channel activity. This NAADP-induced activation of TRP-ML1 channels could not be observed in lysosomes from TRP-ML1−/− cells, but was restored by introducing a TRP-ML1 transgene into these cells. Microscopic Ca2+ fluorescence imaging showed that NAADP significantly increased intracellular Ca2+ concentration to 302.4 ± 74.28 nM (vs. 180 ± 44.13 nM of the basal) in TRP-ML1+/+ cells, but it had no effect in TRP-ML1−/− cells. If a TRP-ML1 gene was transfected into TRP-ML1−/− cells, the Ca2+ response to NAADP was restored to the level comparable to TRP-ML1+/+ cells. Functionally, confocal microscopy revealed that NAADP significantly enhanced the dynamic interaction of endosomes and lysosomes and the lipid delivery to lysosomes in TRP-ML1+/+ cells. This functional action of NAADP was abolished in TRP-ML1−/− cells, but restored after TRP-ML1 gene was rescued in these cells. Our results suggest that NAADP increases lysosomal TRP-ML1 channel activity to release Ca2+, which promotes the interaction of endosomes and lysosomes and thereby regulates lipid transport to lysosomes. Failure of NAADP-TRP-ML1 signaling may be one of the important mechanisms resulting in intracellular lipid trafficking disorder and consequent mucolipidosis.
Smad2 and PEA3 cooperatively regulate transcription of response gene to complement 32 in TGF-β-induced smooth muscle cell differentiation of neural crest cells
Authors: Huang Wen-Yan , Xie Weibing , Guo Xia , Li Fengmin , Jose Pedro A. , Chen Shi-You
Published: May 2011

Response gene to complement 32 (RGC-32) is activated by transforming growth factor- β (TGF-β) and plays an important role in smooth muscle cell (SMC) differentiation from neural crest Monc-1 cells. The molecular mechanism governing TGF-β activation of RGC-32, however, remains to be determined. The present studies indicate that TGF-β regulates RGC-32 gene transcription. Sequence analysis revealed a Smad binding element (SBE) located in the region from −1344 to −1337 bp upstream of the transcription start site of RGC-32 gene. A polyomavirus enhancer activator (PEA3) binding site is adjacent to the SBE. Mutation at either SBE or PEA3 site significantly inhibited RGC-32 promoter activity. Mutations at both sites completely abolished TGF-β-induced promoter activity. Biochemically, TGF-β stimulated recruitment of Smad2, Smad4, and PEA3 to the RGC-32 promoter, as revealed by gel shift and chromatin immunoprecipitation analyses. Functionally, Smad2, but not Smad3, activated RGC-32 promoter. PEA3 appeared to enhance Smad2 activity. In agreement with their function, Smad2, but not Smad3, physically interacted with PEA3. In TGF-β-induced SMC differentiation of Monc-1 cells, knockdown of Smad2 by short hairpin RNA resulted in downregulation of RGC-32 and SMC marker genes. The downregulation of SMC markers, however, was rescued by exogenously introduced RGC-32. These results demonstrate that Smad2 regulation of RGC-32 transcription is essential for SMC differentiation from neural crest cells.
Low birth weight increases susceptibility to renal injury in a rat model of mild ischemia-reperfusion
Authors: Ojeda Norma B.
Published: May 2011

Renal injury due to ischemia-reperfusion (I/R) is the major cause of acute kidney injury. Whether enhanced susceptibility to renal injury due to I/R can be programmed during fetal life is unknown. Epidemiological studies indicate that low birth weight (LBW) individuals are more susceptible to renal injury than normal birth weight (NBW) individuals. Thus, the aim of this study was to test the hypothesis that LBW is associated with an increased susceptibility to renal injury induced by mild renal I/R (15-min ischemia). Systemic and renal hemodynamic parameters were determined in NBW and LBW adult male rats after mild renal I/R; renal superoxide production and tubular injury were also assessed. A subgroup was pretreated with tempol, a superoxide dismutase mimetic, initiated 15 min before ischemia. Mild renal I/R did not alter renal hemodynamic parameters, induce tubular injury, or induce superoxide production in NBW rats. However, renal hemodynamic parameters declined, superoxide production increased, and histological indicators of tubular injury were present following mild renal I/R in LBW rats. Acute treatment with tempol prevented these alterations in LBW rats subjected to mild renal I/R. Thus, these findings suggest that adverse conditions during fetal life can compromise the renal response to subtle insults leading to an increased susceptibility to renal injury, suggesting that LBW individuals may be an “at risk” population for renal disease. Additionally, the outcome of tempol treatment proposes a possible mechanistic pathway involved in mediating enhanced susceptibility to renal injury programmed during fetal life.
Interaction of H+with the extracellular and intracellular aspects of hMATE1
Authors: Dangprapai Yodying , Wright Stephen H.
Published: May 2011

Human multidrug and toxin extrusion 1 (hMATE1, SLC47A1) is a major candidate for being the molecular identity of organic cation/proton (OC/H+) exchange activity in the luminal membrane of renal proximal tubules. Although physiological function of hMATE1 supports luminal OC efflux, the kinetics of hMATE1-mediated OC transport have typically been characterized through measurement of uptake, i.e., the interaction between outward-facing hMATE1 and OCs. To examine kinetics of hMATE1-mediated transport in a more physiologically relevant direction, i.e., an interaction between inward-facing hMATE1 and cytoplasmic substrates, we measured the time course of hMATE1-mediated efflux of the prototypic MATE1 substrate, [3H]1-methyl-4-phenylpyridinium, under a variety of intra- and extracellular pH conditions, from Chinese hamster ovary cells that stably expressed the transporter. In this study, we showed that an IC50/ Kifor interaction between extracellular H+and outward-facing hMATE1 determined from conventional uptake experiments [12.9 ± 1.23 nM (pH 7.89); n = 9] and from the efflux protocol [14.7 ± 3.45 nM (pH 7.83); n = 3] was not significantly different ( P = 0.6). Furthermore, kinetics of interaction between intracellular H+and inward-facing hMATE1 determined using the efflux protocol revealed an IC50for H+of 11.5 nM (pH 7.91), consistent with symmetrical interactions of H+with the inward-facing and outward-facing aspects of hMATE1.
Role of fibroblast growth factor receptor signaling in kidney development
Authors: Bates Carlton M.
Published: May 2011

Fibroblast growth factor receptors (Fgfrs) consist of four signaling family members and one nonsignaling “decoy” receptor, Fgfr-like 1 (Fgfrl1), all of which are expressed in the developing kidney. Several studies have shown that exogenous fibroblast growth factors (Fgfs) affect growth and maturation of the metanephric mesenchyme (MM) and ureteric bud (UB) in cultured tissues. Transgenic and conditional knockout approaches in whole animals have shown that Fgfr1 and Fgfr2 (predominantly the IIIc isoform) in kidney mesenchyme are critical for early MM and UB formation. Conditional deletion of the ligand, Fgf8, in nephron precursors or global deletion of Fgfrl1 interrupts nephron formation. Fgfr2 (likely the IIIb isoform signaling downstream of Fgf7 and Fgf10) is critical for ureteric morphogenesis. Moreover, Fgfr2 appears to act independently of Frs2α (the major signaling adapter for Fgfrs) in regulating UB branching. Loss of Fgfr2 in the MM leads to many kidney and urinary tract anomalies, including vesicoureteral reflux. Thus Fgfr signaling is critical for patterning of virtually all renal lineages at early and later stages of development.