67 research outputs found

    Low-current Scanning Tunneling Microscope for Nanoscale Imaging

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    Advances in the nanotechnology, which is still in its infancy, will depend on our ability todesign, build, replicate, and mass-produce usable nanoscale systems. At sub-nanometer lengthscales, scanning tunneling microscopy (STM) and the related techniques, collectively calledscanning probe microscopies, replace the optical microscopy for real-space imaging andmanipulation of materials. STM operation is based on measurement of current due to tunnelingof electrons across a finite potential barrier between the probe and the sample. In conventionalSTM, tunneling current of tens of nA and probe-sample distance of a few Å are maintained.These conditions, while necessary for atomic-scale imaging under ultra high vacuum environment,are not suited to handle nanostructures. Quantum structures deposited on a flat substrate usuallypresent a non-metallic sample, and the roughness levels involved are much too high forconventional STM. STM operation with low tunneling current (few pA) and larger tunneling gap(several nm) is preferred to overcome these difficulties. This paper presents experimental workand theoretical considerations for developing an atmospheric low-current STM (LC-STM).Researchers from diverse fields can build their own LC-STM for routine imaging and spectroscopy.Several design details are included keeping this aspect in mind

    Plant vigour QTLs co-map with an earlier reported QTL hotspot for drought tolerance while water saving QTLs map in other regions of the chickpea genome

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    Background Terminal drought stress leads to substantial annual yield losses in chickpea (Cicer arietinum L.). Adaptation to water limitation is a matter of matching water supply to water demand by the crop. Therefore, harnessing the genetics of traits contributing to plant water use, i.e. transpiration rate and canopy development dynamics, is important to design crop ideotypes suited to a varying range of water limited environments. With an aim of identifying genomic regions for plant vigour (growth and canopy size) and canopy conductance traits, 232 recombinant inbred lines derived from a cross between ICC 4958 and ICC 1882, were phenotyped at vegetative stage under well-watered conditions using a high throughput phenotyping platform (LeasyScan). Results Twenty one major quantitative trait loci (M-QTLs) were identified for plant vigour and canopy conductance traits using an ultra-high density bin map. Plant vigour traits had 13 M-QTLs on CaLG04, with favourable alleles from high vigour parent ICC 4958. Most of them co-mapped with a previously fine mapped major drought tolerance “QTL-hotspot” region on CaLG04. One M-QTL was found for canopy conductance on CaLG03 with the ultra-high density bin map. Comparative analysis of the QTLs found across different density genetic maps revealed that QTL size reduced considerably and % of phenotypic variation increased as marker density increased. Conclusion Earlier reported drought tolerance hotspot is a vigour locus. The fact that canopy conductance traits, i.e. the other important determinant of plant water use, mapped on CaLG03 provides an opportunity to manipulate these loci to tailor recombinants having low/high transpiration rate and plant vigour, fitted to specific drought stress scenarios in chickpea

    InDel markers: An extended marker resource for molecular breeding in chickpea

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    Chickpea is one of the most important food legumes that holds the key to meet rising global food and nutritional demand. In order to deploy molecular breeding approaches in crop improvement programs, user friendly and cost effective marker resources remain prerequisite. The advent of next generation sequencing (NGS) technology has resulted in the generation of several thousands of markers as part of several large scale genome sequencing and re-sequencing initiatives. Very recently, PCR based Insertion-deletions (InDels) are becoming a popular gel based genotyping solution because of their co-dominant, inexpensive, and highly polymorphic nature. With an objective to expand marker resources for genomics assisted breeding (GAB) in chickpea, whole genome re-sequencing data generated on five parental lines of one interspecific (ICC 4958 × PI 489777) and two intra-specific (ICC 283 × ICC 8261 and ICC 4958 × ICC 1882) mapping populations, were used for identification of InDels. A total of 231,658 InDels were identified using Dindel software with default parameters. Further, a total of 8,307 InDels with ≄20 bp size were selected for development of gel based markers, of which primers could be designed for 7,523 (90.56%) markers. On average, markers appeared at a frequency of 1,038 InDels/LG with a maximum number of markers on CaLG04 (1,952 InDels) and minimum on CaLG08 (360 InDels). In order to validate these InDels, a total of 423 primer pairs were randomly selected and tested on the selected parental lines. A high amplification rate of 80% was observed ranging from 46.06 to 58.01% polymorphism rate across parents on 3% agarose gel. This study clearly reflects the usefulness of available sequence data for the development of genome-wide InDels in chickpea that can further contribute and accelerate a wide range of genetic and molecular breeding activities in chickpea

    Superprocesses as models for information dissemination in the Future Internet

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    Future Internet will be composed by a tremendous number of potentially interconnected people and devices, offering a variety of services, applications and communication opportunities. In particular, short-range wireless communications, which are available on almost all portable devices, will enable the formation of the largest cloud of interconnected, smart computing devices mankind has ever dreamed about: the Proximate Internet. In this paper, we consider superprocesses, more specifically super Brownian motion, as a suitable mathematical model to analyse a basic problem of information dissemination arising in the context of Proximate Internet. The proposed model provides a promising analytical framework to both study theoretical properties related to the information dissemination process and to devise efficient and reliable simulation schemes for very large systems

    Mapping Quantitative Trait Loci of Resistance to Tomato Spotted Wilt Virus and Leaf Spots in a Recombinant Inbred Line Population of Peanut (Arachis hypogaea L.) from SunOleic 97R and NC94022

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    Peanut is vulnerable to a range of diseases, such as Tomato spotted wilt virus (TSWV) and leaf spots which will cause significant yield loss. The most sustainable, economical and eco-friendly solution for managing peanut diseases is development of improved cultivars with high level of resistance. We developed a recombinant inbred line population from the cross between SunOleic 97R and NC94022, named as the S-population. An improved genetic linkage map was developed for the S-population with 248 marker loci and a marker density of 5.7 cM/loci. This genetic map was also compared with the physical map of diploid progenitors of tetraploid peanut, resulting in an overall co-linearity of about 60% with the average co-linearity of 68% for the A sub-genome and 47% for the B sub-genome. The analysis using the improved genetic map and multi-season (2010–2013) phenotypic data resulted in the identification of 48 quantitative trait loci (QTLs) with phenotypic variance explained (PVE) from 3.88 to 29.14%. Of the 48 QTLs, six QTLs were identified for resistance to TSWV, 22 QTLs for early leaf spot (ELS) and 20 QTLs for late leaf spot (LLS), which included four, six, and six major QTLs (PVE larger than 10%) for each disease, respectively. A total of six major genomic regions (MGR) were found to have QTLs controlling more than one disease resistance. The identified QTLs and resistance gene-rich MGRs will facilitate further discovery of resistance genes and development of molecular markers for these important diseases

    Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

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    Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

    Metallic and non-metallic anionic interaction activities estimated with sound velocity and refractive index

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    Density (ρ ± 10−3 kg m−3), sound velocity (VS ± 10−2 ms−1) as acoustic property and refractive index (ÎŒri ± 10−4) for 0.01–0.1 m K2Cr2O7, K2HPO4, KMnO4, KH2PO4, KCl, and KOH aqueous salts with compressibility attained with ion–solvent interaction (ISI) are reported at 0.01 interval and 293.15 K. Ionic internal pressure generated with ISI is expressed as adiabatic compressibility (ÎČ, pa−1) with relative change (ΔÎČ/ÎČ0) and apparent molal compressibility (ϕk, m2N−1) with specific ionic activities for metallic and non-metallic anions. Linear regression generated VS0, ÎŒri0, ϕk0, and ÎČ0 as limiting data for analysis of speed of light and sound. The VS0 as KH2PO4 > K2HPO4 > KOH > K2Cr2O7 > KCl > KMnO4 denoted a minimum VS0 metallic anions. With concentrations, the sound velocity and refractive index are noted as ISI functions where the sound and light waves were in opposite trends. The Mn0 and Cr0 transitional metals with anions of the K2Cr2O7 and KMnO4 have affected the compressibility as K2Cr2O7 > KMnO4 due to 2Cr+6. The VS0, ÎŒri0, ϕk0, and ÎČ0 analyzed their ionic strengths in comparison to HPO4-, H2PO4-, Cl−, and OH− as non-metallic anions considering the interactions as sensors. A molionic model of ion–water interaction was proposed to generalize ion-molecular interactions in industrial mixtures

    Development and evaluation of high-density AxiomÂź CicerSNP Array for high-resolution genetic mapping and breeding applications in chickpea

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    To accelerate genomics research and molecular breeding applications in chickpea, a high-throughput SNP genotyping platform 'AxiomÂź CicerSNP Array' has been designed, developed and validated. Screening of whole-genome resequencing data from 429 chickpea lines identified 4.9 million SNPs, from which a subset of 70 463 high-quality nonredundant SNPs was selected using different stringent filter criteria. This was further narrowed down to 61 174 SNPs based on p-convert score ≄0.3, of which 50 590 SNPs could be tiled on array. Among these tiled SNPs, a total of 11 245 SNPs (22.23%) were from the coding regions of 3673 different genes. The developed AxiomÂź CicerSNP Array was used for genotyping two recombinant inbred line populations, namely ICCRIL03 (ICC 4958 × ICC 1882) and ICCRIL04 (ICC 283 × ICC 8261). Genotyping data reflected high success and polymorphic rate, with 15 140 (29.93%; ICCRIL03) and 20 018 (39.57%; ICCRIL04) polymorphic SNPs. High-density genetic maps comprising 13 679 SNPs spanning 1033.67 cM and 7769 SNPs spanning 1076.35 cM were developed for ICCRIL03 and ICCRIL04 populations, respectively. QTL analysis using multilocation, multiseason phenotyping data on these RILs identified 70 (ICCRIL03) and 120 (ICCRIL04) main-effect QTLs on genetic map. Higher precision and potential of this array is expected to advance chickpea genetics and breeding applications

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    Not AvailableThe present study investigated the effects oforganic and plastic mulching on root d evelopment and nodulation related biometric properties of cowpea determined at different stages of crop growth (60 DAS and at harvest after 90 DAS). At 60 DAS and 90 DAS (at harvest stage), majority of the root development parameters such as root length, number of secondary roots/lateral roots, root weight with nodules, root weight without nodules were recorded highest in plants grown under organic mulch treatments with different level of drip irrigation. Similar trend was also observed in regard to root no dulation development in various mulch treatments. Highest number of nodules per main root of plant i.e., 12.67 and 17.00 after 60 DAS and 90 DAS (at harvest stage) was observed in NM- 80% and OM-60% treatments respectively, At 60 DAS and 90 DAS (at harvest stage), highest number of root nodules per secondary/lateral root (184.67 and 195.50) and total root nodules per plant (195.00 and 211.00) was recorded in organic mulch treatment plants. Fresh weight of total nodule per plant after 60 DAS and 90 DAS was recorded highest in NM100% (2.72 gm) and OM -100 %(5.77gm). In conclusion, overall development of plant roots and root nodulation was positively affected by organic mulches while black mulch has negatively influence on these plant parameters.Not Availabl

    Genotyping-by-sequencing of three mapping populations for identification of candidate genomic regions for resistance to sterility mosaic disease in pigeonpea

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    Sterility mosaic disease (SMD) is one of the serious production constraints that may lead to complete yield loss in pigeonpea. Three mapping populations including two recombinant inbred lines and one F2, were used for phenotyping for SMD resistance at two locations in three different years. Genotyping-by-sequencing approach was used for simultaneous identification and genotyping of SNPs on above mentioned populations. In total, 212,464, 89,699 and 64,798 SNPs were identified in ICPL 20096 × ICPL 332 (PRIL_B), ICPL 20097 × ICP 8863 (PRIL_C) and ICP 8863 × ICPL 87119 (F2) respectively. By using high-quality SNPs, genetic maps were developed for PRIL_B (1,101 SNPs; 921.21 cM), PRIL_C (484 SNPs; 798.25 cM) and F2 (996 SNPs; 1,597.30 cM) populations. The average inter marker distance on these maps varied from 0.84 cM to 1.65 cM, which was lowest in all genetic mapping studies in pigeonpea. Composite interval mapping based QTL analysis identified a total of 10 QTLs including three major QTLs across the three populations. The phenotypic variance of the identified QTLs ranged from 3.6 to 34.3%. One candidate genomic region identified on CcLG11 seems to be promising QTL for molecular breeding in developing superior lines with enhanced resistance to SMD
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