197 research outputs found
A study of annular slurry jet for abrasive waterjet cutting
The objective of this project is to study the performance of an annualr slurry jet nozzle for abrasive waterjet cutting. This nozzle has been invented by Avraham. Harnoy, Department of Mechanical Engineering, NJIT and presented to the patent committee of NJIT in May 1990. This study includes design and development of prototyes and testing of their performance. Moreover, it includes initial theoretical study of the flow behavior.
The idea is based on the merging of a high velocity pure waterjet with an annular jet of a slurry of water and abrasives at low velocity. The two jets merge outside the nozzle. In this way, the major problems of wear and particle disintegration associated with conventional abrasive waterjet systems are eliminated. Our tests shows that it is possibe to merge the two jets and the abrasive particles are accelerated. However, more experiments are required in actual cutting inorder to evaluate the merits of the proposed nozzle. Initial flow analysis helped to elucidate the flow pattern of the merging. More work is required to varify these results
Expression of Aprotinin in anther causes male sterility in tobacco var Petit havana
Expression of many proteinases has been
documented during anther development. Although their
roles are not completely understood, their inhibition
could possibly result in impairment of anther development
leading to male sterility. We proposed that such an
impairment of anther development can be engineered in
plants resulting in male sterile plants that can be used for
hybrid seed production. Here, we report that antherspecific
expression of Aprotinin gene (serine proteinase
inhibitor) in tobacco has resulted in male sterility.
Southern analysis and zymogram analysis confirmed the
integration and expression of Aprotinin gene in the anthers
of the transgenic plants. Transverse sections of anthers of
transgenic male sterile plants showed damaged tapetum.
The pollen germination in the transgenic plants ranged
between 2% and 65% that confirmed the impairment in
pollen production leading to male sterility and low seed
yield. Thus, inhibition of serine proteinases that are
expressed during anther development has resulted in
impaired pollen production and male sterility, though the
exact role of these proteinases in anther development still
has to be elucidated.Council for Scientific and Industrial Research.http://www.springerlink.com/content/0735-9640/nf201
Random amplification of genomic ends (RAGE) as an efficient method for isolation and cloning of promoters and uncloned genomic regions
Isolation of complete coding sequences and regulatory regions is critical for the complete characterization of a gene. Efficient methods to obtain complete genomic or regulatory is important in the process of isolation. The utility of the available genome walking methods are influenced by factors like the size of the genome and the length of the desired sequence. This study utilizes a genome walking method -random amplification of genomic ends (RAGE) efficiently to obtain the 5' -regulatory sequence of a rice stress inducible gene OsAsr1 and to obtain the full length sequence and promoter of the HetR gene of Cylindrospermum stagnale (Cylindrospermum sp. A1345). We demonstrate that this technique can be used for cloning of full length gene and promoters in organisms where whole genome data is unavailable utilising very little sequence information. Our studies show that RAGE can be a strong tool in functional genomics especially in the study of promoter
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Highly Conductive, Stretchable, and Cell-Adhesive Hydrogel by Nanoclay Doping
Electrically conductive materials that mimic physical and biological properties of tissues are urgently required for seamless brain-machine interfaces. Here, a multinetwork hydrogel combining electrical conductivity of 26 S m-1 , stretchability of 800%, and tissue-like elastic modulus of 15 kPa with mimicry of the extracellular matrix is reported. Engineering this unique set of properties is enabled by a novel in-scaffold polymerization approach. Colloidal hydrogels of the nanoclay Laponite are employed as supports for the assembly of secondary polymer networks. Laponite dramatically increases the conductivity of in-scaffold polymerized poly(ethylene-3,4-diethoxy thiophene) in the absence of other dopants, while preserving excellent stretchability. The scaffold is coated with a layer containing adhesive peptide and polysaccharide dextran sulfate supporting the attachment, proliferation, and neuronal differentiation of human induced pluripotent stem cells directly on the surface of conductive hydrogels. Due to its compatibility with simple extrusion printing, this material promises to enable tissue-mimetic neurostimulating electrodes
Induced glare testing â an underutilized test in evaluating visual disability in patients presenting with symptomatic cataracts
Background: Cataract increases intraocular light scatter which affects the retinal image contrast and sensitivity.Symptomatic patients with cataract complain of a drop in the quality of vision or glare affecting daily routine evenwith preserved visual acuity. This study was aimed to quantify the drop in the glare induced visual acuity (VA) andcontrast sensitivity (CS) in different morphological types of cataracts.
Material and methods: This was an observational study on a prospective cohort, conducted at a tertiary-carecentre in South-India. Patients admitted for cataract surgeries between March and September 2017 with BCVA â„6/60 (Snellen) and â„ 40 years were enrolled. LogMAR VA and CS were measured pre and post-operatively, with andwithout glare induction using brightness acuity tester. Patients were sub-categorised based on morphology and thepresence of glare as a symptom. Paired-t test for the pre- and post-operative values and analysis with Bonferroniâsadjustment were the statistical methods used.
Results: Data of 78 patients were sub-categorised and analysed. Glare induction with high glare was significant inall the studied groups. LogMAR VA was affected most in group 3 (0.20, 10 letters, p < 0.05) and the CS in group2 (0.62, 4.1 step drop, p < 0.05). Patients who had glare as a symptom had an average greater drop in LogMAR VA(0.30, p = 0.01) and CS (â0.29, p = 0.03) when induced with a high glare.
Conclusions: All morphological types of cataracts affect VA and CS to a greater extent in conditions of brightlighting. Glare induced VA and CS testing is a sensitive and an adjunct tool to traditional high contrast VA testing,in evaluating the visual dysfunction of patients presenting with symptomatic cataracts
Whole Genome Sequencing and Comparative Genomic Analysis Reveal Allelic Variations Unique to a Purple Colored Rice Landrace (Oryza sativa ssp. indica cv. Purpleputtu)
Purpleputtu (Oryza sativa ssp. indica cv. Purpleputtu) is a unique rice landrace from southern India that exhibits predominantly purple color. This study reports the underlying genetic complexity of the trait, associated domestication and de-domestication processes during its coevolution with present day cultivars. Along-with genome level allelic variations in the entire gene repertoire associated with the purple, red coloration of grain and other plant parts. Comparative genomic analysis using âa panel of 108 rice linesâ revealed a total of 3,200,951 variants including 67,774 unique variations in Purpleputtu (PP) genome. Multiple sequence alignment uncovered a 14 bp deletion in Rc (Red colored, a transcription factor of bHLH class) locus of PP, a key regulatory gene of anthocyanin biosynthetic pathway. Interestingly, this deletion in Rc gene is a characteristic feature of the present-day white pericarped rice cultivars. Phylogenetic analysis of Rc locus revealed a distinct clade showing proximity to the progenitor species Oryza rufipogon and O. nivara. In addition, PP genome exhibits a well conserved 4.5 Mbp region on chromosome 5 that harbors several loci associated with domestication of rice. Further, PP showed 1,387 unique when SNPs compared to 3,023 lines of rice (SNP-Seek database). The results indicate that PP genome is rich in allelic diversity and can serve as an excellent resource for rice breeding for a variety of agronomically important traits such as disease resistance, enhanced nutritional values, stress tolerance, and protection from harmful UV-B rays
The effect of Gonioscopy on keratometry and corneal surface topography
BACKGROUND: Biometric procedures such as keratometry performed shortly after contact procedures like gonioscopy and applanation tonometry could affect the validity of the measurement. This study was conducted to understand the short-term effect of gonioscopy on corneal curvature measurements and surface topography based Simulated Keratometry and whether this would alter the power of an intraocular lens implant calculated using post-gonioscopy measurements. We further compared the effect of the 2-mirror (Goldmann) and the 4-mirror (Sussman) Gonioscopes. METHODS: A prospective clinic-based self-controlled comparative study. 198 eyes of 99 patients, above 50 years of age, were studied. Exclusion criteria included documented dry eye, history of ocular surgery or trauma, diabetes mellitus and connective tissue disorders. Auto-Keratometry and corneal topography measurements were obtained at baseline and at three follow-up times â within the first 5 minutes, between the 10(th)-15(th )minute and between the 20(th)-25(th )minute after intervention. One eye was randomized for intervention with the 2-mirror gonioscope and the other underwent the 4-mirror after baseline measurements. t-tests were used to examine differences between interventions and between the measurement methods. The sample size was calculated using an estimate of clinically significant lens implant power changes based on the SRK-II formula. RESULTS: Clinically and statistically significant steepening was observed in the first 5 minutes and in the 10â15 minute interval using topography-based Sim K. These changes were not present with the Auto-Keratometer measurements. Although changes from baseline were noted between 20 and 25 minutes topographically, these were not clinically or statistically significant. There was no significant difference between the two types of gonioscopes. There was greater variability in the changes from baseline using the topography-based Sim K readings. CONCLUSION: Reversible steepening of the central corneal surface is produced by the act of gonioscopy as measured by Sim K, whereas no significant differences were present with Auto-K measurements. The type of Gonioscope used does not appear to influence these results. If topographically derived Sim K is used to calculate the power of the intraocular lens implant, we recommend waiting a minimum of 20 minutes before measuring the corneal curvature after gonioscopy with either Goldmann or Sussman contact lenses
Toward improved prediction of the bedrock depth underneath hillslopes: Bayesian inference of the bottomâup control hypothesis using highâresolution topographic data
The depth to bedrock controls a myriad of processes by influencing subsurface flow paths, erosion rates, soil moisture, and water uptake by plant roots. As hillslope interiors are very difficult and costly to illuminate and access, the topography of the bedrock surface is largely unknown. This essay is concerned with the prediction of spatial patterns in the depth to bedrock (DTB) using highâresolution topographic data, numerical modeling, and Bayesian analysis. Our DTB model builds on the bottomâup control on freshâbedrock topography hypothesis of Rempe and Dietrich (2014) and includes a mass movement and bedrockâvalley morphology term to extent the usefulness and general applicability of the model. We reconcile the DTB model with field observations using Bayesian analysis with the DREAM algorithm. We investigate explicitly the benefits of using spatially distributed parameter values to account implicitly, and in a relatively simple way, for rock mass heterogeneities that are very difficult, if not impossible, to characterize adequately in the field. We illustrate our method using an artificial data set of bedrock depth observations and then evaluate our DTB model with realâworld data collected at the Papagaio river basin in Rio de Janeiro, Brazil. Our results demonstrate that the DTB model predicts accurately the observed bedrock depth data. The posterior mean DTB simulation is shown to be in good agreement with the measured data. The posterior prediction uncertainty of the DTB model can be propagated forward through hydromechanical models to derive probabilistic estimates of factors of safety.Key Points:We introduce an analytic formulation for the spatial distribution of the bedrock depthBayesian analysis reconciles our model with field data and quantifies prediction and parameter uncertaintyThe use of a distributed parameterization recognizes geologic heterogeneitiesPeer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/137555/1/wrcr22005.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/137555/2/wrcr22005_am.pd
Resilience: New Utopia or New Tyranny? Reflection about the Potentials and Limits of the Concept of Resilience in Relation to Vulnerability Reduction Programmes
Resilience is becoming influential in development and vulnerability reduction sectors such as social protection, disaster risk reduction and climate change adaptation. Policy makers, donors and international development agencies are now increasingly referring to the term. In that context, the objective of this paper was to assess in a critical manner the advantages and limits of resilience. While the review highlights some positive elements âin particular the ability of the term to foster integrated approach across sectorsâ it also shows that resilience has important limitations. In particular it is not a pro-poor concept, and the objective of poverty reduction cannot simply be substituted by resilience building
Addition of elotuzumab to lenalidomide and dexamethasone for patients with newly diagnosed, transplantation ineligible multiple myeloma (ELOQUENT-1): an open-label, multicentre, randomised, phase 3 trial
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