1,496 research outputs found

    Direct Measurement of Periodic Electric Forces in Liquids

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    The electric forces acting on an atomic force microscope tip in solution have been measured using a microelectrochemical cell formed by two periodically biased electrodes. The forces were measured as a function of lift height and bias amplitude and frequency, providing insight into electrostatic interactions in liquids. Real-space mapping of the vertical and lateral components of electrostatic forces acting on the tip from the deflection and torsion of the cantilever is demonstrated. This method enables direct probing of electrostatic and convective forces involved in electrophoretic and dielectroforetic self-assembly and electrical tweezer operation in liquid environments

    Oxidation and chemical state analysis of polycrystalline magnetron sputtered (Ti,Al)N films at ambient and liquid N-2 temperatures

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    In order to improve the functional properties of hard coatings, recent investigations have been directed towards Ti-N based multicomponent materials. The nitride (Ti, Al)N, in particular, with a Ti:Al ratio of 1:1 seems to be a promising alternative to the widely used TiN, exhibits better oxidation resistance and hence improved performance over that of TiN. (Ti, Al)N coatings were de sputter deposited onto 316SS substrates under ambient and liquid nitrogen temperatures. As deposited films were oxidized in a vertical fused-silica tube furnace in pure O-2 flowing atmosphere at temperatures ranging from 700 to 900 degrees C. Scanning electron microscope and atomic force microscope images reveal information about the particle size and film thickness. X-ray photoelectron spectroscopy was employed to study the chemistry of the cop few atomic layers in addition to compositional analysis and information on the details of chemical bonding, The difference in film stoichiometry are compared at two different deposition conditions thus reflecting their behavior under oxidizing conditions

    Change in cost and affordability of a typical and nutritionally adequate diet among socio-economic groups in rural Nepal after the 2008 food price crisis

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    Diet quality is an important determinant of nutrition and food security and access can be constrained by changes in food prices and affordability. Poverty, malnutrition, and food insecurity are high in Nepal and may have been aggravated by the 2008 food price crisis. To assess the potential impact of the food price crisis on the affordability of a nutritionally adequate diet in the rural plains of Nepal, data on consumption patterns and local food prices were used to construct typical food baskets, consumed by four different wealth groups in Dhanusha district in 2005 and 2008. A modelled diet designed to meet household requirements for energy and essential nutrients at minimum cost, was also constructed using the ‘Cost of Diet’ linear programming tool, developed by Save the Children. Between 2005 and 2008, the cost of the four typical food baskets increased by 19% – 26% and the cost of the nutritionally adequate modelled diet increased by 28%. Typical food baskets of all wealth groups were low in macro and micronutrients. Income data for the four wealth groups in 2005 and 2008 were used to assess diet affordability. The nutritionally adequate diet was not affordable for poorer households in both 2005 and 2008. Due to an increase in household income levels, the affordability scenario did not deteriorate further in 2008. Poverty constrained access to nutritionally adequate diets for rural households in Dhanusha, even before the 2008 food price crisis. Despite increased income in 2008, households remain financially unable to meet their nutritional requirements

    Power-law distributions in empirical data

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    Power-law distributions occur in many situations of scientific interest and have significant consequences for our understanding of natural and man-made phenomena. Unfortunately, the detection and characterization of power laws is complicated by the large fluctuations that occur in the tail of the distribution -- the part of the distribution representing large but rare events -- and by the difficulty of identifying the range over which power-law behavior holds. Commonly used methods for analyzing power-law data, such as least-squares fitting, can produce substantially inaccurate estimates of parameters for power-law distributions, and even in cases where such methods return accurate answers they are still unsatisfactory because they give no indication of whether the data obey a power law at all. Here we present a principled statistical framework for discerning and quantifying power-law behavior in empirical data. Our approach combines maximum-likelihood fitting methods with goodness-of-fit tests based on the Kolmogorov-Smirnov statistic and likelihood ratios. We evaluate the effectiveness of the approach with tests on synthetic data and give critical comparisons to previous approaches. We also apply the proposed methods to twenty-four real-world data sets from a range of different disciplines, each of which has been conjectured to follow a power-law distribution. In some cases we find these conjectures to be consistent with the data while in others the power law is ruled out.Comment: 43 pages, 11 figures, 7 tables, 4 appendices; code available at http://www.santafe.edu/~aaronc/powerlaws

    Transcript expression of vesicular glutamate transporters in lumbar dorsal root ganglia and the spinal cord of mice – Effects of peripheral axotomy or hindpaw inflammation

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    Using specific riboprobes, we characterized the expression of vesicular glutamate transporter (VGLUT)1–VGLUT3 transcripts in lumbar 4–5 (L4–5) dorsal root ganglions (DRGs) and the thoracolumbar to lumbosacral spinal cord in male BALB/c mice after a 1- or 3-day hindpaw inflammation, or a 7-day sciatic nerve axotomy. Sham animals were also included. In sham and contralateral L4–5 DRGs of injured mice, VGLUT1-, VGLUT2- and VGLUT3 mRNAs were expressed in ∼45%, ∼69% or ∼17% of neuron profiles (NPs), respectively. VGLUT1 was expressed in large and medium-sized NPs, VGLUT2 in NPs of all sizes, and VGLUT3 in small and medium-sized NPs. In the spinal cord, VGLUT1 was restricted to a number of NPs at thoracolumbar and lumbar segments, in what appears to be the dorsal nucleus of Clarke, and in mid laminae III–IV. In contrast, VGLUT2 was present in numerous NPs at all analyzed spinal segments, except the lateral aspects of the ventral horns, especially at the lumbar enlargement, where it was virtually absent. VGLUT3 was detected in a discrete number of NPs in laminae III–IV of the dorsal horn. Axotomy resulted in a moderate decrease in the number of DRG NPs expressing VGLUT3, whereas VGLUT1 and VGLUT2 were unaffected. Likewise, the percentage of NPs expressing VGLUT transcripts remained unaltered after hindpaw inflammation, both in DRGs and the spinal cord. Altogether, these results confirm previous descriptions on VGLUTs expression in adult mice DRGs, with the exception of VGLUT1, whose protein expression was detected in a lower percentage of mouse DRG NPs. A detailed account on the location of neurons expressing VGLUTs transcripts in the adult mouse spinal cord is also presented. Finally, the lack of change in the number of neurons expressing VGLUT1 and VGLUT2 transcripts after axotomy, as compared to data on protein expression, suggests translational rather than transcriptional regulation of VGLUTs after injury.Fil: Malet, Mariana. Universidad Austral. Facultad de Ciencias Biomédicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Vieytes, C. A.. Universidad Austral. Facultad de Ciencias Biomédicas; ArgentinaFil: Lundgren, K. H.. University of Cincinnati; Estados UnidosFil: Seal, R. P.. University of Pittsburgh; Estados UnidosFil: Tomasella, María Eugenia. Universidad Austral. Facultad de Ciencias Biomédicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Seroogy, K. B.. University of Cincinnati; Estados UnidosFil: Hökfelt, T.. Karolinska Huddinge Hospital. Karolinska Institutet; SueciaFil: Gebhart, G. F.. University of Pittsburgh; Estados UnidosFil: Brumovsky, Pablo Rodolfo. Universidad Austral. Facultad de Ciencias Biomédicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. University of Pittsburgh; Estados Unido

    Intracranial Hypertension Secondary to Eosinophilic Meningitis Caused by Angiostrongylus Cantonensis

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    Angiostrongylus Cantonensis, a nematode, is a well-known cause of eosinophilic meningitis in endemic areas such as Southeast Asia, the Pacific Islands, and Hawaii. Nevertheless, an increasing number of cases in the southeast of the U.S. have been documented recently, specifically in Louisiana, Texas, and Florida. Infection is acquired after ingesting undercooked fresh water snails, mollusks, or undercooked vegetables contaminated by the slime from infected snails or slugs. Typical signs and symptoms include fever, general malaise, meningeal signs, headaches, photophobia, nausea and vomiting. Here we present a 23 year-old woman who presented to our emergency department with signs and symptoms consistent with intracranial hypertension, malaise, mild photophobia, and without fever, or meningeal signs. We also provide a review of the most recent literature regarding eosinophilic meningitis secondary to A. cantonensis

    Identification and evaluation of suitable reference genes for gene expression studies in the whitefly Bemisia tabaci (Asia I) by reverse transcription quantitative realtime PCR

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    This study presents a reliable method for performing reverse transcription quantitative realtime PCR (RT-qPCR) to measure gene expression in the whitefly Bemisia tabaci (Asia I) (Gennadius) (Hemiptera: Aleyrodidae), utilising suitable reference genes for data normalisation. We identified orthologs of commonly used reference genes (actin (ACT), cyclophilin 1 (CYP1), elongation factor 1α (EF1A), glyceraldehyde 3-phosphate dehydrogenase (GAPDH), ribosomal protein L13a (RPL13A), and α-tubulin (TUB1A)), measured the levels of their transcripts by RT-qPCR during development and in response to thermal stress, and evaluated their suitability as endogenous controls using geNorm, BestKeeper, and NormFinder programs. Overall, TUB1A, RPL13A, and CYP1 were the most stable reference genes during B. tabaci development, and TUB1A, GAPDH, and RPL13A were the most stable reference genes in the context of thermal stress. An analysis of the effects of reference gene choice on the transcript profile of a developmentally-regulated gene encoding vitellogenin demonstrated the importance of selecting the correct endogenous controls for RT-qPCR studies. We propose the use of TUB1A, RPL13A, and CYP1 as endogenous controls for transcript profiling studies of B. tabaci development, whereas the combination of TUB1A, GAPDH, and RPL13A should be employed for studies into thermal stress. The data pre- sented here will assist future transcript profiling studies in whiteflies

    Fabrication, Dynamics, and Electrical Properties of Insulated SPM Probes for Electrical and Electromechanical Imaging in Liquids

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    Insulated cantilever probes with a high aspect ratio conducting apex have been fabricated and their dynamic and electrical properties analyzed. The cantilevers were coated with silicon dioxide and a via was fabricated through the oxide at the tip apex and backfilled with tungsten to create an insulated probe with a conducting tip. The stiffness and Q-factor of the cantilevers increased after the modifications and their resonances shifted to higher frequencies. The coupling strength between the cantilever and the coating are determined. The applications to conductive and electromechanical imaging of ferroelectric domains are illustrated, and a probe apex repair process is demonstrated.Comment: 3 fig

    Adoption of Rational Farming Technology for Development of a Model for Exploring Sustainable Farming Practice in Farmer’s Field

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    The effectivity of Inhana Rational Farming (IRF) Technology was critically evaluated as a model of Sustainable Farming Practice in farmers’ field using okra (variety : Shakti - F1 hybrid) as test crop. The stusy was conducted at Binuria village in Birbhum District of West Bengal during February to October (2013). The village is in close vicinity of Visva Bharati University, Santiniketan. The study area lies in 23.660 N and 87.630E at about 179 ft. above MSL, with level to nearly level landscape. The experiment was laid down as per randomized block design (RBD) with 7 treatments replicated 3 times. The treatments included local farming practice with chemical inputs, organic farming practice (Inhana Rational Farming (IRF) Technology’ developed by Dr. P. Das Biswas, Founder, Inhana Biosciences, Kolkata) as well as integrated farming practice (combination of chemical and organic inputs for both soil and plant management). The most significant finding was that 100% reduction of chemical pesticide can be economically viable in the very first year with adoption of IRF Organic Package of Practice, under which 13.6% yield increase was recorded as compared to conventional farmer’s practice. Also when IRF was adopted for integrated cultivation model, higher yield as well as higher net income was obtained in comparison to conventional Farmer’s practice. Upto 144.5% higher Nitrogen Utilization efficiency and 32.8 % higher partial factor productivity was recorded under treatments with IRF Package. This higher response might be due to increased uptake and utilization of indigenous nutrients under the influence of high quality Novcom compost containing huge population (in order of 1016 c.f.u per gm moist compost) of self- generated microbes, which led to better nutrient (both macro and micro) mineralization in soil for plant uptake. This was also complimented by IRF Plant Management Package, which perhaps enhanced plant physiological functioning in terms of better N uptake and its utilization within plants
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