Investigation of ion induced bending mechanism for nanostructures

Ion induced bending is a promising controlled technique for manipulating nanoscale structures. However, the underlying mechanism of the process is not well understood. In this letter, we report a detailed study of the bending mechanism of Si nanowires (NWs) under Ga+ irradiation. The microstructural changes in the NW due to ion beam irradiation are studied and molecular dynamics simulations are used to explore the ion–NW interaction processes. The simulation results are compared with the microstructural studies of the NW. The investigations inform a generic understanding of the bending process in crystalline materials, which we suggest to be feasible as a versatile manipulation and integration technique in nanotechnology

Precedence-type Test based on Progressively Censored Samples

In this paper, we introduce precedence-type tests for testing the hypothesis that two distribution functions are equal, which is an extension of the precedence life-test rst proposed by Nelson (1963), when the two samples are progressively Type-II censored. The null distributions of the test statistics are derived. Critical values for some combination of sample sizes and censoring schemes for the proposed tests are presented. Then, we present the exact power functions under the Lehmann alternative, and compare the exact power as well as simulated power (under location-shift) of the proposed precedence test based on nonparametric estimates of CDF with other precedence-type tests. We then examine the power properties of the proposed test procedures through Monte Carlo simulations. Two examples are presented to illustrate all the test procedures discussed here. Finally, we make some concluding remarks.Precedence test; Product-limit estimator; Type-II progressive censoring; Life-testing; level of significance; power; Lehmann alternative; Monte Carlo simulations

Observational Evidence of Sausage-Pinch Instability in Solar Corona by SDO/AIA

We present the first observational evidence of the evolution of sausage-pinch instability in Active Region 11295 during a prominence eruption using data recorded on 12 September 2011 by the Atmospheric Imaging Assembly (AIA) onboard the Solar Dynamics Observatory (SDO). We have identified a magnetic flux tube visible in AIA 304 \AA\ that shows curvatures on its surface with variable cross-sections as well as enhanced brightness. These curvatures evolved and thereafter smoothed out within a time-scale of a minute. The curved locations on the flux tube exhibit a radial outward enhancement of the surface of about 1-2 Mm (factor of 2 larger than the original thickness of the flux tube) from the equilibrium position. AIA 193 \AA\ snapshots also show the formation of bright knots and narrow regions inbetween at the four locations as that of 304 \AA\ along the flux tube where plasma emission is larger compared to the background. The formation of bright knots over an entire flux tube as well as the narrow regions in < 60 s may be the morphological signature of the sausage instability. We also find the flows of the confined plasma in these bright knots along the field lines, which indicates the dynamicity of the flux tube that probably causes the dominance of the longitudinal field component over short temporal scales. The observed longitudinal motion of the plasma frozen in the magnetic field lines further vanishes the formed curvatures and plasma confinements as well as growth of instability to stablize the flux tube.Comment: 12 pages, 5 figure

On the polarization of the resonance lines of lithium and sodium atoms by electron impact

The polarization of the resonance lines of 6Li, 7Li and Na, excited by electron impact, are calculated using the Glauber approximation. The present results are in good agreement with experimental values and with other theoretical calculations in the energy range from 2 eV to 5 eV

Flow injection analysis of iron in rain water with thiocyanate and surfactant

This paper explains a new procedure for flow injection analysis (FIA) determination of iron in rain water based on the colour reaction of Fe3+ with thiocyanate ions in the presence of the cationic surfactant cetylpyridinium chloride (CPC). The value of apparent molar absorptivity of the complex in terms of iron is (2.00) x 104 l mole-1 cm-1 at an absorption maximum of 490 nm. The detection limit of the method is 8 ppb Fe. The sample throughput is 90 samples/h at a flow rate of 4.0 ml/min. The reaction mechanism, optimization of FIA variables, and effect of various types of surfactant are described. None of the tested anions and cations interfered with the determination of iron. The method was used for the quantification and flux determination of iron in rain water

Gene encoding γ-carbonic anhydrase is cotranscribed with argC and induced in response to stationary phase and high CO2 in Azospirillum brasilense Sp7

<p>Abstract</p> <p>Background</p> <p>Carbonic anhydrase (CA) is a ubiquitous enzyme catalyzing the reversible hydration of CO₂to bicarbonate, a reaction underlying diverse biochemical and physiological processes. Gamma class carbonic anhydrases (γ-CAs) are widespread in prokaryotes but their physiological roles remain elusive. At present, only γ-CA of <it>Methanosarcina thermophila </it>(Cam) has been shown to have CA activity. Genome analysis of a rhizobacterium <it>Azospirillum brasilense</it>, revealed occurrence of ORFs encoding one β-CA and two γ-CAs.</p> <p>Results</p> <p>One of the putative γ-CA encoding genes of <it>A. brasilense </it>was cloned and overexpressed in <it>E. coli</it>. Electrometric assays for CA activity of the whole cell extracts overexpressing recombinant GCA1 did not show CO₂hydration activity. Reverse transcription-PCR analysis indicated that <it>gca1 </it>in <it>A. brasilense </it>is co-transcribed with its upstream gene annotated as <it>argC</it>, which encodes a putative <it>N</it>-acetyl-γ-glutamate-phosphate reductase. 5'-RACE also demonstrated that there was no transcription start site between <it>argC </it>and <it>gca1</it>, and the transcription start site located upstream of <it>argC </it>transcribed both the genes (<it>argC-gca1</it>). Using transcriptional fusions of <it>argC</it>-<it>gca1 </it>upstream region with promoterless <it>lacZ</it>, we further demonstrated that <it>gca1 </it>upstream region did not have any promoter and its transcription occurred from a promoter located in the <it>argC </it>upstream region. The transcription of <it>argC-gca1 </it>operon was upregulated in stationary phase and at elevated CO₂atmosphere.</p> <p>Conclusions</p> <p>This study shows lack of CO₂hydration activity in a recombinant protein expressed from a gene predicted to encode a γ-carbonic anhydrase in <it>A. brasilense </it>although it cross reacts with anti-Cam antibody raised against a well characterized γ-CA. The organization and regulation of this gene along with the putative <it>argC </it>gene suggests its involvement in arginine biosynthetic pathway instead of the predicted CO₂hydration.</p

Analysis of Environmental Factors in Rice Mill Workers of Uttar Pradesh, India

This study was carried out in the Barabanki District, of Uttar Pradesh. In this study a group of 50 healthy workers and another group of (100 exposed) labours working in rice mill workers were randomly selected with ages ranging from 20-35, 35-50, 50-65 years. The blood samples were taken from them and estimation of haemoglobin (Darkbins method), total Leukocyte counts were analysed. The result shows the% of haemoglobin of exposed labours from different age groups 20-35, 35-50, 50-65 are non-significant (P&gt;0.05) Total leukocyte counts in labours of different age groups 20-35, 35-50, 50-65 are insignificant (P&lt;0.05) Results were compared in a mean, and on the basis of period exposure. Considering the hazards of exposure to rice husk dust, this study incorporated the basic haematological parameters, erythrocyte sedimentation rate and the total leukocyte count. The idea was to identify a simple, readily available and cost effective screening test that could help in identifying the presence of disease, its severity, in rice mill workers potentially related to their workplace5. The findings of this study recognized the role of rice husk dust for a longer duration in decline of haematological parameters as per tests conducted among rice mills workers. The present work was undertaken to study the health problems related to the workplace environment of rice mill workers. Diseases of the respiratory system induced by occupational dusts are influenced by the duration of exposure The aim of the study is to investigate the impairment due to environmental factors in rice mill workers. In addition, the amount of dust particle at this station is greater than the standard value of allowance. All workers have restrictive lung conditions related to breathing filled with dust during the milling process every day

Hematological disorders in Rice mill workers of district Shahjahanpur, Uttar Pradesh, India

India is a second largest rice growing countries in the world. A large number of unskilled laborers are employed for paddy processing. In rice mills, most of the workers have shown adverse health effects associated with occupational exposure to rice husk dust (WHO, 1968). Present study was conducted to determine the hematological disorders in rice mill workers in rural/urban areas of Uttar Pradesh. Total numbers of 100 blood samples were collected from rural and urban area from rice mill workers of Shahjahanpur district. Majority of hematological test parameters showed reduced levels in rice mill workers. This study may helpful in preventing longstanding harmful effects of such exposures. It is also useful for preventing environmental risks. It is concluded that rice husk dust causes deterioration of hematological parameters in subjects working at rice mill. The findings of this study recognized the role of rice husk dust for a longer duration in decline of hematological parameters as per tests conducted among rice mills workers