bluuebunny/crossref_metadata_2025 huggingface dataset:
Capture technique and fish personality: angling targets timid bluegill sunfish,Lepomis macrochirus
Authors: Wilson Alexander D.M. , Binder Thomas R. , McGrath Keegan P. , Cooke Steven J. , Godin Jean-Guy J.
Published: May 2011

Size-selective harvesting associated with commercial and recreational fishing practices has been shown to alter life history traits through a phenomenon known as fishing-induced evolution. This phenomenon may be a result of selection pathways targeting life-history traits directly or indirectly through correlations with behavioral traits. Here, we report on the relationship between individual differences in behavior and capture technique (beach seining versus angling) in wild-caught juvenile bluegill sunfish ( Lepomis macrochirus ). Both fish caught by using a seine net (seined) and fish caught by using a lure (angled) were individually tested under standardized laboratory conditions for their boldness, water-column use, and general activity. Observed inter-individual differences in boldness were strongly correlated with method of capture in the wild. Fish caught by angling were more timid and had fewer ectoparasites than fish caught using a seine net. However, this relationship did not carry over to an experiment in a large outdoor pool with seine-caught, individually tagged wild fish, where bolder individuals were more likely to be angled in open water away from refuges than more timid individuals, based on their previously assessed boldness scores. Our study is both novel and important, as it describes the relationship between capture technique and boldness in a natural population and underscores the potential risk of sampling biases associated with method of animal capture for behavioral, population, and conservation biologists.
Estimation of feeding patterns for piscivorous fish using individual prey data from stomach contents
Authors: Berg Casper Willestofte , Temming Axel
Published: May 2011

The problem of estimating temporal feeding patterns using stomach data is considered, where the time of ingestion for each prey item can be predicted through a gastric evacuation model. The arrival of prey is modelled as a nonhomogeneous Poisson process with known periodic intensity. A maximum likelihood approach is used to estimate the intensity, which is assumed to be the same for all predators, incorporating different uncertainties for the arrival time of each prey item. The method is applied to a case where a population of whiting ( Merlangius merlangus ) is feeding on sandeel ( Ammodytes marinus ), and peak feeding periods around dusk and dawn are identified.
Mysis diluvianapopulation and cohort dynamics in Lake Ontario before and after the establishment ofDreissena spp.,Cercopagis pengoi, andBythotrephes longimanus
Authors: Johannsson Ora E. , Bowen Kelly L. , Holeck Kristen T. , Walsh Maureen G.
Published: May 2011

We investigated population responses of Mysis to ecosystem changes induced by invasion of dreissenids and predatory cladocerans, Cercopagis and Bythotrephes . Lake productivity declined as dreissenids invaded the offshore region. Whole-lake mysid biomass was compared before (early 1990s) and after (2002–2007) the invasion period; it declined 40%–45%. Abundance of young mysids and presence of a summer cohort increased with summer, epilmnetic, nighttime zooplankton biomass (i.e., food biomass index). Cercopagis + Bythotrephes biomass was negatively correlated with this index, implicating them in the mysid decline. Eggs per gravid female increased with autumn, total-water-column zooplankton biomass, reflecting the greater use of hypolimnetic waters by adults. Reproductive success was below replacement during the period 2002–2005. First-year mysid growth rate was maintained while population abundance declined, suggesting selection for individuals that feed effectively at low food concentrations. Mortality rates in the first and second years were dependent on cohort density, indicating that competition for food limited abundance in the first 2 years. Fish predation indices (smelt and alewife combined) were correlated positively with mortality rates and negatively with abundance in the third year. Thus, mysids cannot support as many fish in invaded compared with non-invaded lakes. They may also not be a stable food resource; unusual cohort losses occurred in some years.
The promises and pitfalls of including decadal-scale climate forcing of recruitment in groundfish stock assessment
Authors: Haltuch Melissa A. , Punt André E.
Published: May 2011

Concurrent declines in demersal fish stock abundances and shifts in long-term average environmental conditions have been well documented in the Pacific. Management advice ignoring environmental forcing of recruitment may cause stocks to be over- or under-harvested, so it is important to consider including environmental forcing on recruitment in stock assessment models. Simulation testing is used to determine the statistical power of stock assessments to identify long-term, decadal-scale environmental forcing of recruitment and the ability to estimate management reference points when the duration of the fisheries time series is equal to or less than the period of the environmental cycle. Commonly used assessment methods generally lead to lower total type I (incorrectly rejecting the null hypothesis of no environmental impact) and type II (failing to detect an environmental impact when such a relationship exists) error rates. The promise of integrating environmental data with decadal-scale variability directly into stock assessments via the stock–recruitment relationship is outweighed by the pitfall of high type I error rates that are due to fishing-induced stock declines that coincide with directional environmental change. However, the impact of type I errors can be minimized by choosing an appropriate combination of assessment method and reference point estimators.
Seasonal forecasting of tuna habitat for dynamic spatial management
Authors: Hobday Alistair J. , Hartog Jason R. , Spillman Claire M. , Alves Oscar
Published: May 2011

Capture of the target, bycatch, and protected species in fisheries is often regulated through spatial measures that partition fishing effort, including areal closures. In eastern Australian waters, southern bluefin tuna (SBT, Thunnus maccoyii ) are a quota-limited species in a multispecies longline fishery; minimizing capture by nonquota holders is an important management concern. A habitat preference model (conditioned with electronic tag data) coupled with ocean reanalysis data has been used since 2003 to generate real-time predicted maps of SBT distribution (nowcasts). These maps are used by fishery managers to restrict fisher access to areas with high predicted SBT distribution. Here we use the coupled ocean–atmosphere model, POAMA (predictive ocean atmosphere model for Australia), and a habitat model to forecast SBT distribution at lead times of up to 4 months. These forecasts are comparable with nowcasts derived from the operational system, and show skill in predicting SBT habitat boundaries out to lead-times of 3–4 months. For this fishery, seasonal forecasts can provide managers and fishers with valuable insights into future habitat distributions for the upcoming months, to better inform operational decisions.
SHAPE EVOLUTION IN ONE-DIMENSIONAL ZnO NANOSTRUCTURES GROWN FROM ZnO NANOPOWDER SOURCE: VAPOR–LIQUID–SOLID VERSUS VAPOR–SOLID GROWTH MECHANISMS
Authors: DHARA SOUMEN , GIRI P. K.
Published: May 2011

Here we report on the growth and evolution of ZnO nanowires grown from ZnO nanopowder as a source material using a horizontal muffle furnace. The shape evolution has been studied with variation in growth temperature and zinc vapor pressure. The structural analysis on these nanostructures shows c-axis oriented aligned growth. Scanning electron microscopy imaging of these nanostructures revealed the shape evolution from nanowires to nanoribbons and then to nanorods as the growth temperature increases from 650°C to 870°C. At 650°C, only vertical nanowires have been observed and with increase in growth temperature nanowires transform to nanoribbons and then to nanorods at 870°C. And we also observed simultaneous growth of nanorods and nanoribbons under a specific growth condition. We believe that these nanowires and nanorods were formed by vapor–liquid–solid growth mechanism (catalyst-mediated growth), whereas nanoribbons were grown by vapor–solid growth mechanism (without the aid of a metal catalyst). We observed simultaneous occurrence of vapor–liquid–solid and vapor–solid growth mechanisms at a particular growth temperature. These ZnO nanowires exhibit bound exciton related UV emission at ~379 nm, and defect-emission band in the visible region. Possible growth mechanism, shape evolution, and simultaneous growth of two types of one-dimensional ZnO nanostructures under the same growth condition are discussed.
SELF-ORDERING ELECTROCHEMICAL SYNTHESIS OF TiO2 NANOTUBE ARRAYS: CONTROLLING THE NANOTUBE GEOMETRY AND THE GROWTH RATE
Authors: KANT KRISHNA , LOSIC DUSAN
Published: May 2011

We report the fabrication of highly ordered TiO 2 nanotube arrays employing electrochemical anodization of titanium using an organic electrolyte comprised of water, NH 4 F , and ethylene glycol. To achieve the self-ordering regime of TiO 2 nanotube growth and reliable fabrication optimal potential window between 80 and 100 V was determined. We show that anodization voltage can be used not only to control nanotube diameters (70–180 nm) but also to have impact on nanotube growth rate. The anodization voltage and anodization time were used to adjust the length of TiO 2 nanotube (thickness of nanotube layer). TiO 2 nanotube array films and self-supporting layers with thickness from < 5 μm to > 250 μm were routinely fabricated.
EXPERIMENTAL INVESTIGATIONS ON NANOSIZED FERRIC OXIDE AND ITS LPG SENSING
Authors: YADAV B. C. , SINGH SATYENDRA , YADAV ANURADHA , SHUKLA TRIPTI
Published: May 2011

Nanosized particles of α- Fe 2 O 3 in the range of 17–64 nm were synthesized via hydroxide precipitation. The synthesized powder was investigated by XRD employing CuK α radiation and 2θ geometry. SEM images show the nanosheet like morphology. The pellet of this sensing material was made by hydraulic press under a uniaxial pressure of 616 MPa. The LPG sensing properties of α- Fe 2 O 3 were investigated at room temperature for different exposure times of LPG. A maximum value of sensitivity and sensor response were found 3 and 213%, respectively for an exposure time of 300 s. Electrical properties of α- Fe 2 O 3 in air were also investigated by measuring temperature–resistance (R–T) characteristics and plotting them as Arrhenius plot. Activation energy was calculated by thermal resistance method and found to have a value 1.07 eV.
INVESTIGATIONS ON THE ELECTRICAL PROPERTIES OF ZnO NANORODS AND COMPOSITES FOR PHOTOVOLTAIC AND ELECTROCHEMICAL APPLICATIONS
Authors: HARI PARAMESWAR , BYRCZEK MICHAL , TEETERS DALE , UTEKAR PRAVIN
Published: May 2011

ZnO nanorods grown by hydrothermal technique on glass, Zinc, and Indium tin oxide (ITO) substrates exhibit both open and closed hexagonal structures. On the nanoscale, closed ZnO nanostructures exhibit two types of ion conduction regions as revealed by AC-impedance spectra collected through the tip of an atomic force microscope (AFM). One region has higher impedance values (apparent values of approximately 107 ohms) with two semicircles. Two semicircles are indicative of a ZnO structure composed of bulk and grain boundary conduction. Other regions were found to have impedance values that were two orders of magnitude lower (apparent values of 105 ohms). This indicates that these ZnO films have two conduction pathways. The polyethylene oxide ( PEO )– ZnO nanorod composite was made by spin-coating the ZnO rods growing from the ITO substrate with PEO. In the PEO – ZnO composite film, only the AC impedance values of 105 ohms were observed. This is higher than PEO electrolyte without ZnO nanorods. Since regions of higher impedance were not seen in the PEO – ZnO nanorod composites, the polymer electrolyte either dominated the conduction of the system or suppressed the first pathway of higher impedance in the ZnO rods.
ELECTRICAL TRANSPORT CHARACTERISTICS OF FOCUSED ION BEAM FABRICATED Au, Cu NANOWIRES
Authors: RAJPUT NITUL S. , SINGH ABHISHEK K. , SHUKLA NEERAJ , KULKARNI VISHWAS N.
Published: May 2011

Nanowires of Au and Cu were fabricated using a top–down method in which focused ion beam (FIB) milling process has been used. The width of the fabricated nanowires has been kept in the range of 45 to 300 nm and the length in the range of 2–10 μm. In situ electrical measurements of the nanowires were carried out. The resistivities of these wires are found to be higher (five to nine times larger than their bulk values). These results have been understood on the basis of increase in the electron surface scattering due to one-dimensional confinement of the electrons. Also, other effects such as nanogap formation in the range of 40 nm to few hundreds of nanometers, structural changes of the wires, increase of current density with time at constant applied voltage, etc. have been observed during measurements.
GOLD NANOPARTICLES-EMBEDDED TRANSPARENT CONDUCTING OXIDES: PREPARATION, CHARACTERIZATION, AND TUNING OF THE OPTICAL PROPERTIES
Authors: LAHA RANJIT , KASIVISWANATHAN S.
Published: May 2011

Gold nanoparticles ( AuNP )-embedded indium oxide and indium tin oxide thin films were prepared by DC and DC magnetron reactive co-sputtering techniques. The concentration and size distribution of AuNP were changed by deposition conditions. The nanoparticles-embedded films were characterized by X-ray diffraction, transmission electron microscopy, and optical spectrophotometry. The X-ray diffraction data showed the polycrystalline nature of indium oxide and indium tin oxide along with the Au (111) peak confirming the presence of elemental AuNP in the matrices. The transmission electron microscope studies revealed that AuNP are distributed in the matrices in different shapes and sizes with the average sizes as 40 nm and 10 nm, respectively for DC-sputtered and DC magnetron-sputtered films. The optical absorbance measurements showed the SPR peak due to AuNP to be around 600 nm. The position and intensity of the SPR peak could be tuned from 650 to 570 nm by changing the concentration of AuNP and annealing the films in oxygen and Ar for different durations.
EVIDENCE OF THICKNESS-DEPENDENT STABILITY OF NANOMETER RANGE W/Ni MULTILAYERS AGAINST SWIFT HEAVY ION IRRADIATION
Authors: BAGCHI SHARMISTHA , LALLA N. P. , ANWAR SHAHID
Published: May 2011

We report microstructural characterization studies, including cross-sectional TEM, carried out on pristine and swift heavy ion irradiated W / Ni multilayers with different bilayer thicknesses. Our results very clearly show a strong thickness dependence of the SHI effect; thinner Ni -layers get severely affected while the thicker ones remain intact. This has been confirmed using a multilayer having composite bilayer thickness. This result appears to indicate toward the possible electron conferment and its implication on the dissipation of electronic excitation in metals.
EFFECT OF GROWTH TEMPERATURE ON THE CATALYST-FREE GROWTH OF LONG SILICON NANOWIRES USING RADIO FREQUENCY MAGNETRON SPUTTERING
Authors: DHARA SOUMEN , GIRI P. K.
Published: May 2011

We have grown metal catalyst free, straight Si nanowires (NWs) with high aspect ratio of about 130 on Si (100) substrate using radio frequency magnetron sputtering. Thin Si seed layer on thermally oxidized substrate was used for catalyst-free growth. Then Si deposition was done on that substrate using sputtering technique followed by heat treatment at different temperatures (900°C–1100°C). Sample heated at 1000°C results in straight, long, and uniform cylindrical shaped Si NWs with diameter 62–74 nm and length up to 8 μm, whereas sample heated above 1000°C transformed toward nanorods with larger diameter. However, no significant growth of Si NWs took place at 900°C. Sputter deposition technique provides an alternate fabrication route for Si NW synthesis. For comparison, we have also grown Au catalyst assisted Si NWs on Si (100) substrate by similar process. These nanowires also show similar morphology with diameter 48–65 nm and aspect ratio about 165. Growth mechanism and effect of growth temperatures on the structure and morphology of Si NWs are discussed.
IMPROVED CHEMICAL SYNTHESIS OF GRAPHENE USING A SAFER SOLVOTHERMAL ROUTE
Authors: SINGH DILIP KUMAR , IYER P. K. , GIRI P. K.
Published: May 2011

Graphene has been synthesized using thermal decomposition of ethyl alcohol in a medium pressure autoclave. The synthesis was carried out in the presence of strong alkaline solution at a temperature of ~230°C and pressure of 60 bar. The as-synthesized graphene has been characterized using atomic force microscopy (AFM) and high-resolution transmission electron microscopy (HRTEM). AFM analysis on various graphene sheets shows the presence of monolayer (n = 1) to trilayer (n = 3) graphene sheets with thickness of ~1.168 nm. HRTEM studies confirm the high quality of graphene obtained after purification of as-synthesized product. Use of chemically nonexplosive material for synthesis and reduced reaction time along with the absence of post-pyrolysis process make it a commercially viable process for bulk production of graphene.
THE EFFECT OF FILTER TYPE, CONCENTRATION, AND TYPE OF CARBON NANOTUBE ON THE BUCKYPAPER SURFACE QUALITY
Authors: KAMALVAND M. , MADHKHAN M. , HAMIDI B. , VAHEDI A. , ZIAEI-RAD S. , VAZIRI M. A.
Published: May 2011

Buckypaper is a thin sheet fabricated from the aggregation of carbon nanotubes. The generally accepted method for forming such carbon nanotube (CNT) films involves the use of stable suspension of carbon nanotubes in water. These suspensions can then be membrane-filtered under pressure to yield uniform films. After preparation of a stable solution, it should be membrane-filtrated on the surface of a filter. Usually, the quality of a buckypaper depends on sonication time and power, surfactant type and concentration, filter type, and concentration of carbon nanotube. In order to investigate the surface quality of buckypapers, low-magnification images could give rather useful information about the roughness of surface. Analysis of the 100 × images clearly shows that with increasing the suspension concentration, the smoothness of buckypaper surface will decrease. Therefore, from this viewpoint, decreasing the concentration can enhance the quality of the buckypaper. Surface of the filter also affects on the buckypaper quality. Therefore, for filtration of the suspension, a filter with suitable material, pore sizes, and surface should be used. As the pore sizes of the filter are usually small, the filtration process may be very time-consuming. Since the process is carring out under pressure and also due to the brittle nature of the buckypaper, removal of the buckypaper from the surface of the filter is a very serious and important stage and depends on the filter type, concentration, and type of CNTs. The buckypaper usually can be removed from the filter mechanically. The type of CNTs (MWNT or SWNT) may change the above-mentioned factors.
A DUAL OPTICAL TWEEZER FOR MICRORHEOLOGY OF BACTERIAL SUSPENSIONS
Authors: YOGESHA  , RAGHU A. , NAGESH B. V. , BHATTACHARYA SARBARI , MOHANA D. C. , ANANTHAMURTHY SHARATH
Published: May 2011

A dual optical tweezer has been built around an inverted microscope with high numerical aperture objective (N.A 1.4). The setup is versatile and can be used both as a single and a dual tweezer, and in the dual mode, enables us to optically trap two micron-sized latex beads within a few microns from each other in solution. Using this setup, we report measurements of the microrheological parameters of Pseudomonas fluorescens and Bacillus subtilis bacterial suspensions. We study the variation of viscoelastic moduli of these bacterial suspensions as a function of their cell count in solution. A comparison with inactive bacteria of corresponding cell count enables us to characterize the activity of the bacterial samples in terms of an average force that the bacteria exerts on the trapped bead. This work paves way for studies of interesting nonlinear rheological phenomena at small length scales.
DSETHVASAN: A NOVEL NANODRUG AGAINST SLEEPING SICKNESS
Authors: SETH D. , BRAHMACHARY R. L. , ULRICHS C. , MONDAL M. , MUKHOPADHAYAY S. , SASMAL N. K. , CHANDRA R. , GUPTA S. , GOSWAMI A.
Published: May 2011

Sleeping sickness (causal agent, Trypanosoma sp. parasite) causes huge morbidity and mortality in Africa (both human and livestock) in particular and zoo animals worldwide. Three of the four currently approved drugs (Pentamidine, Melarsoprol, Eflornithine, and Nifurtimox) were developed over 50 years ago. Current therapies are unsatisfactory due to unacceptable level of side effects. Pentamidine, an aromatic diamidine, safest so far, inhibits mitochondrial enzymes. Furthermore, it is effective only in early stages of infections and not on the later stage. Melarsoprol, practically insoluble in water, is very toxic and it is given intravenously (i.v.) for later stage infections only. Other drugs like eflornithine and nitfurtimox are also unsatisfactory for various reasons. Human serum derived high-density lipoprotein (HDL; not mouse or any other mammalian HDL) shows trypanolytic effect in vitro and in vivo on T. brucei. But the mechanism of action of human HDL is far from clear. In the absence of novel drug leads, nanodrugs might be valid options as nanoparticles show better accessibility to cells, supramolecular interactions due to enormous increase in surface area to volume ratio, altered partition coefficient, etc. Surface-modified hydrophobic microsilica (FS), mixture of micro- and nanosilica (Dsethvasan) and nanosilica (AL) were characterized by UV–Vis, DLS, SEM, EDAX, AFM, and XRD. Trypanosoma evansi collected from infected horses were injected in mice. Control infected mouse (n = 30) showed 100% mortality within 72±24 h of injection. Dsethvasan-treated mice (n = 30) survived for 192±24 h. FS-treated mice (n = 30) survived for 120±24 h but the AL-treated mice (n = 30) died within 72±24 h of inoculation like infected control. Hydrophobic Dsethvasan which consists of pure amorphous forms of micro- and nanosilica works better than FS (AL is not at all effective). Therefore, micro- and nanomixture of amorphous silica is best suited for treating Trypanosoma infection in mice. The possible role of ratio of higher to lower size class has been discussed.
EFFICIENT DELIVERY OF NUCLEIC ACIDS BY USING MODIFIED POLYETHYLENIMINE-BASED NANOPARTICLES
Authors: GOYAL RITU , TRIPATHI SUSHIL KUMAR , SWAMI ARCHANA , GUPTA KAILASH CHAND
Published: May 2011

Branched polyethylenimine, (b PEI, 25 kDa), was converted into nanoparticles by using three different crosslinkers, 1,6-hexanebisphosphate (HP), adipic acid (AA), and 1,4-butane dialdehyde (BA), having same carbon chain length (C-6), and the effect of ionic and covalent crosslinking on the transfection efficiency was studied. The synthesized nanoparticles were characterized by 1H-NMR, IR, DLS, AFM, and TEM. The entire series of nanoparticles was tested for their toxicity and ability to deliver genes in COS-1 and CHO cell lines. It was observed that, AAP-3 nanoparticle/DNA complex exhibited highest transfection efficiency (~2.1–10.7 folds) than the native PEI and commercially available transfection reagents, such as GenePORTER 2TM, LipofectamineTM, and SuperfectTM, with cell viability >80%. Among the series, the highest cell viability was observed with BAP nanoparticles (>96%). These nanoparticles were able to deliver GFP-siRNA very efficiently inside the cells with ~76%–90% suppression of EGFP expression. Cellular trafficking studies showed that these nanoparticles carry pDNA inside the nucleus of the cells within 2 h of the addition to the cells.
STUDIES ON MECHANICAL PROPERTIES OF CARBON NANOTUBES/HIGH-DENSITY POLYETHYLENE NANOCOMPOSITES BY SMALL PUNCH TECHNIQUE
Authors: MEHTA HARSH , WANGSHUL HMANTHA , KANAGARAJ S.
Published: May 2011

Carbon nanotubes have been used as a reinforcing element to improve the properties of polymer matrix. An attempt has been made to investigate the mechanical behavior of carbon nanotubes–high-density polyethylene (CNT–HDPE) nanocomposites using a small punch technique. The designed punch assembly was fabricated and mounted on the Universal Testing Machine. The experimental setup was calibrated using aluminum and mild steel where the relative error was found to be within 7%. The mechanical properties of the nanocomposites, were studied by varying the weight fraction of CNT in HDPE. It was found that Young's modulus and ultimate strength of nanocomposites were increased by 37% and 36%, respectively for 1 wt% of CNTs in HDPE and they were found to increase linearly with an increase in CNT concentration. It is concluded that the small punch technique was successfully developed and tested to characterize the mechanical properties of HDPE and CNT–HDPE nanocomposites.
SYNTHESIS AND CHARACTERIZATION OF BIFUNCTIONAL CoFe2O4–ZnS NANOCOMPOSITE
Authors: BORAH J. P. , BORGOHAIN C. , SARMA K. C. , SENAPATI K. K. , PHUKAN P.
Published: May 2011

The synthesis of composite magnetic nanomaterials has received increasing attention due to their electronic, magnetic, catalytic, and chemical or biological sensing properties. We have prepared cobalt ferrite–zinc sulfide nanocomposites by a chemical route. The synthesized nanocomposites were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), vibrating sample magnetometer (VSM), and photoluminescence spectrometer (PL). The fluorescent magnetic nanoparticles (FMNPs) had a typical diameter of 30±5 nm and saturation magnetization of 5.8 emu g-1 at room temperature. So, these FMNPs may be potentially applied in different fields such as optoelectronic devices, biolabeling, imaging, drug targeting, bioseparation, magnetic fluid hyperthermia, etc.
ON THE PHONON CONFINEMENT AND PARTICLE SIZE IN TiO2:ZnO NANOCOMPOSITE
Authors: KANMANI S. S. , RAJKUMAR N. , RAMACHANDRAN K.
Published: May 2011

TiO 2 nanoparticles and TiO 2: ZnO (80:20) nanocomposites were prepared by chemical method, and X-ray diffraction, high resolution transmission electron microscopy, and Raman analysis of the samples showed a strong anatase phase and they are further used to find and compare the particle size.
IMPACT OF ZrO2 NANOPARTICLES ON IONIC TRANSPORT AND ELECTROCHEMICAL PROPERTIES OF NANOCOMPOSITE GEL POLYMER ELECTROLYTE: PPG (4000)–AgCF3SO3:ZrO2
Authors: SUTHANTHIRARAJ S. AUSTIN , KUMAR R. , PAUL B. JOSEPH
Published: May 2011

The phenomenon of enhancement of ionic transport and electrochemical behavior of a new poly (propylene glycol) (PPG 4000)–silver triflate ( AgCF3SO3 ) as a result of incorporation of varying concentrations of ZrO 2 nanoparticles have been investigated. The significant conformal changes and the strength of interactions along with chain enlargement of polymer matrix have been analyzed by means of FT-IR and DSC studies as well. From the ac impedance measurements, it is clear that the addition of filler particles favors an increase in the conductivity by more than two orders of magnitude and that the typical sample PPG4– AgCF3SO3 :10 wt% ZrO 2 exhibits a maximum conductivity of 2.9 × 10-3 Scm-1 along with the cationic transference number of 0.49 at room temperature.
PHOTOCATALYTIC DEGRADATION OF ORGANIC DYE USING NANO ZnO
Authors: SARAVANAN R. , SHANKAR H. , RAJASUDHA G. , STEPHEN A. , NARAYANAN V.
Published: May 2011

Photocatalytic degradation of methylene blue was investigated using nanocrystalline ZnO prepared by chemical precipitation and thermal decomposition routes. In both preparation routes zinc acetate dihydrate was used as the precursor. In the case of precipitation route, sodium hydroxide was used as the precipitating agent at room temperature, but in thermal decomposition method the precursor was just calcined at 450°C for 30 min. The structural and morphological properties were studied by X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), and Scanning Electron Microscopy (SEM). The sample prepared by precipitation route exhibits higher photocatalytic activity than that by thermal decomposition method and the reasons for the enhanced photocatalytic activity have been discussed in detail.
NANOSTRUCTURED ITO THIN FILMS BY RF SPUTTERING FOR ACETONE SENSOR
Authors: PANDYA H. J. , CHANDRA SUDHIR , VYAS A. L.
Published: May 2011

A sensor for detection of acetone vapors using nanostructured ITO thin film is reported. The ITO film was sputter-deposited on glass substrate using RF magnetron sputtering at 200 W RF power in argon atmosphere at 20 mTorr pressure. The film was then annealed at 450°C for 1h in air. The sensing area was kept to be 3 mm × 3 mm. Two aluminum pads of 7 mm × 4 mm size were formed using lift-off technique for electrical contacts. The crystallinity, microstructure, and acetone vapor-sensing properties were systematically investigated. The stability of the sensing films with aging and temperature variations was also investigated.
ANALYSIS OF SHORT CHANNEL EFFECTS IN NANOSCALE MOSFETS
Authors: JOSHI GARIMA , CHOUDHARY AMIT
Published: May 2011

A quantum-mechanical model, by combining the quantum mechanical carrier distribution and short channel effects (SCEs) with the classical carrier transport is used to predict the I–V characteristics at sub-90 nm technology nodes. I–V characteristics of 90, 65, and 45 nm for developed model are benchmarked. The analysis of SCEs, namely, velocity saturation, mobility degradation, and threshold voltage shift, has been carried out in this paper for these technology nodes. The detailed physical view of the variation of these effects with channel length (L) and drain voltage (Vds) has been presented. Also, the impact of including these effects in I–V equations of nanoscale MOSFETs is included in the paper. The observations presented in this paper will help in developing a clear understanding of physical behavior of nanoscale MOSFETs.
STRUCTURAL AND MAGNETIC PROPERTIES OF NANOCRYSTALLINE Sn0.98Co0.02O2 UNDER DIFFERENT ANNEALING CONDITIONS
Authors: MOHANTY SUNITA , RAVI S. , JENA H. S. , MANIVANNAN V.
Published: May 2011

Nanocrystalline samples of pure and 2 at% Co -doped SnO 2 was prepared by a co-precipitate technique with a crystallite size of the order 10 nm. The homogeneity and single-phase nature of the sample was confirmed by using various characterization techniques, such as X-ray diffraction, transmission electron microscope, and Fourier infrared spectroscopy. Magnetization measurement shows a signature of room temperature ferromagnetism. The reduction in magnetization with decrease in crystalline size has been explained as a result of restriction in the range of bound magnetic polaron interaction. The samples prepared under nitrogen gas environment exhibit improvement in ferromagnetic behavior and enhanced electrical conductivity.
COMPUTATIONAL MODELING AND SIMULATION OF NANOMOLECULAR SWITCH FOR ALZHEIMER'S DISEASE (A GENE SILENCING TECHNIQUE)
Authors: RADHAGAYATHRI K. U. , NAMBOORI P. K. KRISHNAN , MOHANDAS V. P. , SUBEESH T. , GOPAKUMAR DEEPA , RAMACHANDRAN K. I.
Published: May 2011

The design of artificial gene regulatory networks has paved way for the construction of therapeutic gene circuits that would find application in next generation gene therapy approaches. The main challenge in such designs is in selecting the appropriate genetic components to make up the circuit in order to produce the anticipated or desired behavior. To eliminate this complexity, computational simulation tools are used to guide circuit design. This involves selection and genetic modification of components, until the required system behavior is achieved.

In this work, we have designed a model for a synthetic nanogene network. The gene expression involved in diseases caused by mutation, like cancer, Alzheimer's disease (AD), etc., can be effectively controlled by "Nanogene silencing genetic switch". Here, we have considered the case of Alzheimer's disease.

Genes that are responsible for genetic AD are APP, PSEN1, and PSEN2. Antimutagenic study of phytochemicals has been carried out with the common AD causing APP gene mutation. By our computational analysis, phytochemicals like curcumin, eugenol, and limonene have been identified as "molecular switch" devices to prevent mutation of AD gene. All these chemicals are found to be strongly interacted with the AD gene without making changes to the remaining part of the sequence. Among the analyzed chemicals, curcumin is found to be most interacting with AD gene protecting it from mutation. Hence, inclusion of curcumin-containing food items in our menu would prevent Alzheimer's disease to a large extent.

This technique is a type of gene therapy leading to silencing of the mutated part of the gene and preventing mutation.
SURFACE ENERGY TRANSFER BETWEEN NANOSTRUCTURED GOLD AND DYE MOLECULES
Authors: SEN TAPASI , PATRA AMITAVA
Published: May 2011

Here, we report the surface energy transfer from Rhodamine 6G dye to assembled gold nanoparticles. There is a pronounced effect on the PL and a shortening of the lifetime of the dye, and the calculated distances (d) between the donor and acceptor are 85.5 Å, 91.3 Å, and 109.5 Å for 50, 75, and 125 μM MNA capped Au NPs, respectively. Analysis suggests that the energy transfer from dye to the assembled Au nanoparticles is dominant by surface energy transfer and it follows 1/d4 distance dependence.
Similar effects of all WNK3 variants on SLC12 cotransporters
Authors: Cruz-Rangel Silvia , Melo Zesergio , Vázquez Norma , Meade Patricia , Bobadilla Norma A. , Pasantes-Morales Herminia , Gamba Gerardo , Mercado Adriana
Published: May 2011

With-no-lysine kinase 3 (WNK3) is a member of a subfamily of serine/threonine kinases that modulate the activity of the electroneutral cation-coupled chloride cotransporters. WNK3 activates NKCC1/2 and NCC and inhibits the KCCs. Four splice variants are generated from the WNK3 gene. Our previous studies focused on the WNK3–18a variant. However, it has been suggested that other variants could have different effects on the cotransporters. Thus, the present study was designed to define the effects of all WNK3 variants on members of the SLC12 family. By RT-PCR from a fetal brain library, exons 18b and 22 were separately amplified and subcloned into the original WNK3–18a or catalytically inactive WNK3-D294A to obtain all four potential combinations with and without catalytic activity (18a, 18a+22, 18b, and 18b+22). The basal activity of the cotransporters and the effects of WNK3 isoforms were assessed in Xenopus laevis oocytes coinjected with each of the WNK3 variant cRNAs. In isotonic conditions, the basal activity of NCC and NKCC1/2 were increased by coinjection with any of the WNK3. The positive effects occurred even in hypotonic conditions, in which the basal activity of NKCC1 is completely prevented. Consistent with these observations, when expressed in hypotonicity, all KCCs were active, but in the presence of any of the WNK3 variants, KCC activity was completely reduced. That is, NKCC1/2 and NCC were inhibited, even in hypertonicity, while KCCs were activated, even in isotonic conditions. We conclude that the effects of all WNK3 variants toward SLC12 proteins are similar.
Serum starvation: caveat emptor
Authors: Pirkmajer Sergej , Chibalin Alexander V.
Published: May 2011

Serum starvation is one of the most frequently performed procedures in molecular biology and there are literally thousands of research papers reporting its use. In fact, this method has become so ingrained in certain areas of research that reports often simply state that cells were serum starved without providing any factual details as to how the procedure was carried out. Even so, we quite obviously lack unequivocal terminology, standard protocols, and perhaps most surprisingly, a common conceptual basis when performing serum starvation. Such inconsistencies not only hinder interstudy comparability but can lead to opposing and inconsistent experimental results. Although it is frequently assumed that serum starvation reduces basal activity of cells, available experimental data do not entirely support this notion. To address this important issue, we studied primary human myotubes, rat L6 myotubes and human embryonic kidney (HEK)293 cells under different serum starvation conditions and followed time-dependent changes in important signaling pathways such as the extracellular signal-regulated kinase 1/2, the AMP-activated protein kinase, and the mammalian target of rapamycin. Serum starvation induced a swift and dynamic response, which displayed obvious qualitative and quantitative differences across different cell types and experimental conditions despite certain unifying features. There was no uniform reduction in basal signaling activity. Serum starvation clearly represents a major event that triggers a plethora of divergent responses and has therefore great potential to interfere with the experimental results and affect subsequent conclusions.
Calcium-dependent inhibition of adrenal TREK-1 channels by angiotensin II and ionomycin
Authors: Enyeart John J. , Liu Haiyan , Enyeart Judith A.
Published: May 2011

Bovine adrenocortical cells express bTREK-1 K+ (bovine KCNK2) channels that are inhibited by ANG II through a Gq-coupled receptor by separate Ca2+ and ATP hydrolysis-dependent signaling pathways. Whole cell and single patch clamp recording from adrenal zona fasciculata (AZF) cells were used to characterize Ca2+-dependent inhibition of bTREK-1. In whole cell recordings with pipette solutions containing 0.5 mM EGTA and no ATP, the Ca2+ ionophore ionomycin (1 μM) produced a transient inhibition of bTREK-1 that reversed spontaneously within minutes. At higher concentrations, ionomycin (5–10 μM) produced a sustained inhibition of bTREK-1 that was reversible upon washing, even in the absence of hydrolyzable [ATP]i. BAPTA was much more effective than EGTA at suppressing bTREK-1 inhibition by ANG II. When intracellular Ca2+ concentration ([Ca2+]i) was buffered to 20 nM with either 11 mM BAPTA or EGTA, ANG II (10 nM) inhibited bTREK-1 by 12.0 ± 4.5% ( n=11) and 59.3 ± 8.4% ( n=4), respectively. Inclusion of the water-soluble phosphatidylinositol 4,5-bisphosphate (PIP2) analog DiC8PI(4,5)P2 in the pipette failed to increase bTREK-1 expression or reduce its inhibition by ANG II. The open probability ( Po) of unitary bTREK-1 channels recorded from inside-out patches was reduced by Ca2+ (10–35 μM) in a concentration-dependent manner. These results are consistent with a model in which ANG II inhibits bTREK-1 K+ channels by a Ca2+-dependent mechanism that does not require the depletion of membrane-associated PIP2. They further indicate that the Ca2+ source is located in close proximity within a “Ca2+ nanodomain” of bTREK-1 channels, where [Ca2+]i may reach concentrations of >10 μM. bTREK-1 is the first two-pore K+ channel shown to be inhibited by Ca2+ through activation of a G protein-coupled receptor.
Intracellular angiotensin II activates rat myometrium
Authors: Deliu Elena , Tica Andrei A. , Motoc Dana , Brailoiu G. Cristina , Brailoiu Eugen
Published: May 2011

Angiotensin II is a modulator of myometrial activity; both AT1 and AT2 receptors are expressed in myometrium. Since in other tissues angiotensin II has been reported to activate intracellular receptors, we assessed the effects of intracellular administration of angiotensin II via microinjection on myometrium, using calcium imaging. Intracellular injection of angiotensin II increased cytosolic Ca2+ concentration ([Ca2+]i) in myometrial cells in a dose-dependent manner. The effect was abolished by the AT1 receptor antagonist losartan but not by the AT2 receptor antagonist PD-123319. Disruption of the endo-lysosomal system, but not that of Golgi apparatus, prevented the angiotensin II-induced increase in [Ca2+]i. Blockade of AT1 receptor internalization had no effect, whereas blockade of microautophagy abolished the increase in [Ca2+]i produced by intracellular injection of angiotensin II; this indicates that microautophagy is a critical step in transporting the peptide into the endo-lysosomes lumenum. The response to angiotensin II was slightly reduced in Ca2+-free saline, indicating a major involvement of Ca2+ release from internal stores. Blockade of inositol 1,4,5-trisphosphate (IP3) receptors with heparin and xestospongin C or inhibition of phospholipase C (PLC) with U-73122 abolished the response to angiotensin II, supporting the involvement of PLC-IP3 pathway. Angiotensin II-induced increase in [Ca2+]i was slightly reduced by antagonism of ryanodine receptors. Taken together, our results indicate for the first time that in myometrial cells, intracellular angiotensin II activates AT1-like receptors on lysosomes and activates PLC-IP3-dependent Ca2+ release from endoplasmic reticulum; the response is further augmented by a Ca2+-induced Ca2+ release mechanism via ryanodine receptors activation.
Mechanisms of facilitation of synaptic glutamate release by nicotinic agonists in the nucleus of the solitary tract
Authors: Kalappa Bopanna I. , Feng Lin , Kem William R. , Gusev Alexander G. , Uteshev Victor V.
Published: May 2011

The nucleus of the solitary tract (NTS) is the principal integrating relay in the processing of visceral sensory information. Functional nicotinic acetylcholine receptors (nAChRs) have been found on presynaptic glutamatergic terminals in subsets of caudal NTS neurons. Activation of these receptors has been shown to enhance synaptic release of glutamate and thus may modulate autonomic sensory-motor integration and visceral reflexes. However, the mechanisms of nAChR-mediated facilitation of synaptic glutamate release in the caudal NTS remain elusive. This study uses rat horizontal brainstem slices, patch-clamp electrophysiology, and fluorescent Ca2+ imaging to test the hypothesis that a direct Ca2+ entrance into glutamatergic terminals through active presynaptic non-α7- or α7-nAChR-mediated ion channels is sufficient to trigger synaptic glutamate release in subsets of caudal NTS neurons. The results of this study demonstrate that, in the continuous presence of 0.3 μM tetrodotoxin, a selective blocker of voltage-activated Na+ ion channels, facilitation of synaptic glutamate release by activation of presynaptic nAChRs (detected as an increase in the frequency of miniature excitatory postsynaptic currents) requires external Ca2+ but does not require activation of presynaptic Ca2+ stores and presynaptic high- and low-threshold voltage-activated Ca2+ ion channels. Expanding the knowledge of mechanisms and pharmacology of nAChRs in the caudal NTS should benefit therapeutic approaches aimed at restoring impaired autonomic homeostasis.
Thermotolerance and heat acclimation may share a common mechanism in humans
Authors: Kuennen Matthew , Gillum Trevor , Dokladny Karol , Bedrick Edward , Schneider Suzanne , Moseley Pope
Published: May 2011

Thermotolerance and heat acclimation are key adaptation processes that have been hitherto viewed as separate phenomena. Here, we provide evidence that these processes may share a common basis, as both may potentially be governed by the heat shock response. We evaluated the effects of a heat shock response-inhibitor (quercetin; 2,000 mg/day) on established markers of thermotolerance [gastrointestinal barrier permeability, plasma TNF-α, IL-6, and IL-10 concentrations, and leukocyte heat shock protein 70 (HSP70) content]. Heat acclimation reduced body temperatures, heart rate, and physiological strain during exercise/heat stress) in male subjects ( n = 8) completing a 7-day heat acclimation protocol. These same subjects completed an identical protocol under placebo supplementation (placebo). Gastrointestinal barrier permeability and TNF-α were increased on the 1st day of exercise/heat stress in quercetin; no differences in these variables were reported in placebo. Exercise HSP70 responses were increased, and plasma cytokines (IL-6, IL-10) were decreased on the 7th day of heat acclimation in placebo; with concomitant reductions in exercise body temperatures, heart rate, and physiological strain. In contrast, gastrointestinal barrier permeability remained elevated, HSP70 was not increased, and IL-6, IL-10, and exercise body temperatures were not reduced on the 7th day of heat acclimation in quercetin. While exercise heart rate and physiological strain were reduced in quercetin, this occurred later in exercise than with placebo. Consistent with the concept that thermotolerance and heat acclimation are related through the heat shock response, repeated exercise/heat stress increases cytoprotective HSP70 and reduces circulating cytokines, contributing to reductions in cellular and systemic markers of heat strain. Exercising under a heat shock response-inhibitor prevents both cellular and systemic heat adaptations.
β-Adrenergic receptor blockade blunts postexercise skeletal muscle mitochondrial protein synthesis rates in humans
Authors: Robinson Matthew M. , Bell Christopher , Peelor Frederick F. , Miller Benjamin F.
Published: May 2011

β-Adrenergic receptor (AR) signaling is a regulator of skeletal muscle protein synthesis and mitochondrial biogenesis in mice. We hypothesized that β-AR blockade blunts postexercise skeletal muscle mitochondrial protein synthesis rates in adult humans. Six healthy men (mean ± SD: 26 ± 6 yr old, 39.9 ± 4.9 ml·kg−1·min−1peak O2uptake, 26.7 ± 2.0 kg/m2body mass index) performed 1 h of stationary cycle ergometer exercise (60% peak O2uptake) during 1) β-AR blockade (intravenous propranolol) and 2) administration of saline (control). Skeletal muscle mitochondrial, myofibrillar, and sarcoplasmic protein synthesis rates were assessed using [2H5]phenylalanine incorporation into skeletal muscle proteins after exercise. The mRNA content of signals for mitochondrial biogenesis was determined using real-time PCR. β-AR blockade decreased mitochondrial (from 0.217 ± 0.076 to 0.135 ± 0.031%/h, P < 0.05), but not myofibrillar or sarcoplasmic, protein synthesis rates. Peroxisome proliferator-activated receptor-γ coactivator-1α mRNA was increased ∼2.5-fold ( P < 0.05) at 5 h compared with 1 h postexercise but was not influenced by β-AR blockade. We conclude that decreased β-AR signaling during cycling can blunt the postexercise increase in mitochondrial protein synthesis rates without affecting mRNA content.
Preference of IRES-mediated initiation of translation during hibernation in golden-mantled ground squirrels, Spermophilus lateralis
Authors: Pan Peipei , van Breukelen Frank
Published: May 2011

Mammalian hibernation involves virtual cessation of energetically consumptive processes normally vital to homeostasis, including gene transcription and protein synthesis. As animals enter torpor, the bulk of initiation of translation is blocked at a body temperature of 18°C in golden-mantled ground squirrels [ Spermophilus (Callospermophilus) lateralis ]. Previous data demonstrated regulation of cap-dependent initiation of translation during torpor. We asked what happens to cap-independent, specifically, internal ribosome entry site (IRES)-mediated initiation of translation during hibernation. We analyzed polysome fractions for mRNAs that are known to contain or not to contain IRES elements. Here, we show that mRNAs harboring IRES elements preferentially associate with ribosomes as a torpor bout progresses. Squirrels allowed to naturally complete a torpor cycle have a higher IRES preference index than those animals that are prematurely aroused from torpor. Data indicate that this change in preference is not associated with gene expression, i.e., change is due to change in mRNA association with ribosomes as opposed to mRNA abundance. Thus, although processes like transcription and translation are virtually arrested during torpor, ribosomes are preferentially loaded with IRES-containing transcripts when squirrels arouse from torpor and translation resumes. Differential translation of preexisting mRNAs may allow for the preferential production of key stress proteins critical for survival of physiological insults that are lethal to other mammals.