369 research outputs found

    A23187-Channel behaviour: fluorescence study

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    Pyranine entrapped soylipid liposomes have been used as a model system to study the proton transport across membrane in the presence of A23187, a carboxylic ionophore specific for electroneutral exchange of divalent cations. An apparent rate constant (kapp) for transport of protons has been determined from the rate of change of fluorescence intensity of pyranine by stopped flow rapid kinetics in the presence of proton gradient The variation of kapp has been studied as a function of ionophore concentration and the results have been compared with gramicidin-a well known channel former under the similar experimental conditions. The rates thus obtained showed that A23187 is not only a simple carrier but also shows channel behaviour at high concentration of ionophore

    Genetic diversity among three Indian populations of black tiger shrimp (Penaeus monodon Fabricious, 1798) using microsatellite DNA markers

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    Genetic variation is an essential factor while selecting superior stocks for breeding programs. Eight microsatellite loci (TUZX pm2.27, TUZX pm2.28, TUZX pm2.36, TUZX pm2.69, TUZX pm4.84, TUZX pm4.87, TUZX pm6.1 and TUZX pm4.9) were used for molecular characterisation of Penaeus monodon collected from three different locations in India, viz., Kakinada and Chennai on the east coast and Mumbai on the west coast and all the loci were found to be highly polymorphic. The number of alleles and genotypes across the loci ranged from 5 to 23 and 42 to 98, respectively. The observed heterozygosity among the populations across the loci ranged from 0 to 0.1678. The overall FST value was found to be 0.021 (<0.05), which implies a low degree of population differentiation in the species. On the basis of pair-wise allelic differentiation and UPGMA dendrogram, the investigated samples from three locations were allocated in to two distinct populations composed of east coast and west coast populations

    Orientation Field Estimation for Latent Fingerprint Using Region Segmentation

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    ABSTRACT:Latent fingerprint matching has played a critical role in identifying suspects and criminals. However, compared torolled and plain fingerprint matching, latent fingerprint identification accuracy is much lower due to complex background noise,poor ridge quality and overlapping structured noise in latent images. Accordingly, manual markup of various features (e.g.,region of interest, singular points and minutiae) is typically necessary to extract reliable features from latents. To reduce thismarkup cost and to improve the consistency in feature markup, fully automatic and highly accurate latentmatching algorithms are needed. In this paper, we propose an automatic region segmentation algorithm whose goal is to separate the fingerprint region (region of interest) from background. It utilizes both ridge orientation and frequency features. The orientation tensor is used to obtain the symmetric patterns of fingerprint ridge orientation, and local Fourier analysis method is used to estimate the local ridge frequency of the latent fingerprint. Candidate fingerprint (foreground) regions are obtained for each feature type; an intersection of regions from orientation and frequency features localizes the true latent fingerprint regions. To verify the viability of the proposed region segmentation algorithm, we evaluated the segmentation results in two aspects: a comparison with the ground truth foreground and matching performance based on segmented region

    A transient numerical model for desiccant-coated fixed-bed regenerators and compensation for transient sensor errors

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    This is an Accepted Manuscript of an article published by Taylor & Francis in Science and Technology for Build Environment on 06-January 2022, available at: https://doi.org/10.1080/23744731.2021.2017236Natural Science and Engineering Research Council (NSERC), Tempeff North America Inc., Winnipeg, Canada (Project No: 533225-18), ASHRAE.Peer ReviewedDesiccant-coated fixed-bed regenerators (FBRs) can achieve high effectiveness due to high ratio of energy transfer area to volume, and therefore, they are favourable air-to-air energy recovery exchangers for HVAC systems. However, unlike other types of energy recovery exchangers, the air properties (i.e., temperature and humidity) at the outlet of FBRs vary with time. The variations in outlet airflow properties can cause errors in measurements because the measurements include the FBR and sensors transient responses. In this paper, a numerical model is developed to evaluate the performance of desiccant-coated FBRs and their transient operation. The model consists of an exchanger model (FBR model) and sensor (temperature and humidity) models to distinguish the actual performance of the FBR alone from the measured performance, which includes both the FBR and the sensor's response. The model is validated with experimental measurements and available results in the literature. The model can decouple the measured response of the FBR and sensors to predict the FBR performance. This paper's main contribution is an insight into the complex heat and mass transfer processes in desiccant-coated FBRs and measurement sensors. The results of this paper could be used to provide practical recommendations for humidity measurements of different types of desiccant-coated FBRs developed for HVAC applications. Furthermore, the measurement requirements in the current testing standards (ASHRAE 84 and CSA C439-18 standards) for FBRs are examined. Recommendations from this paper could be implemented in future versions of these standards

    Experimental Investigation on Thermo-Hydraulic Performance of Triangular Cross-Corrugated Flow Passages

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    National Science and Engineering Research Council (NSERC), Tempeff North America Inc., Winnipeg, Canada, (Project No: 533225-18)Peer ReviewedHeat exchangers made of corrugated flow passages generally have better thermo-hydraulic performance compared to parallel flow passages. The corrugation angle (), corrugation pattern, and the ratio of depth to pitch (hch/Pch) are critical geometrical parameters influencing the heat transfer and pressure drop in corrugated flow passages. This paper experimentally investigates heat transfer and pressure drop characteristics of triangular-shaped cross-corrugated flow passages for the range of 25°<<75° and 0.13<hch/Pch<0.36. Experiments are performed using representative compact heat exchangers in a small-scale test facility. This study also reports the effects of plate geometry on heat transfer and pressure drop and provides correlations for the average Nusselt number and friction factor. A detailed comparison of test data with relevant literature is also presented. Results of this study will be useful to manufactures and designers for developing high-performance heat exchangers

    Theoretical calculations that determine the stability of the knife holder milling tool on a support sliding in the process of operation

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    In this regard at department of woodworking machines and tools the mill which has an opportunity to change the angles of cutting and an axial corner at the same time is designed and made. It will allow to reduce power by cutting, to increase quality of the processed sur-face and to increase the period of firmness of the tool.На кафедре деревообрабатывающих станков и инструментов спроектирована и изготовлена фреза, у которой есть возможность изменять углы резания и осевой угол одновременно. Это позволит уменьшить мощность на резание, повысить качество обработанной поверхности и увеличить период стойкости инструмента

    Alterations of immune response of non-small lung cancer with azacytidine

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    Innovative therapies are needed for advanced Non-Small Cell Lung Cancer (NSCLC). We have undertaken a genomics based, hypothesis driving, approach to query an emerging potential that epigenetic therapy may sensitize to immune checkpoint therapy targeting PD-L1/PD-1 interaction. NSCLC cell lines were treated with the DNA hypomethylating agent azacytidine (AZA - Vidaza) and genes and pathways altered were mapped by genome-wide expression and DNA methylation analyses. AZA-induced pathways were analyzed in The Cancer Genome Atlas (TCGA) project by mapping the derived gene signatures in hundreds of lung adeno (LUAD) and squamous cell carcinoma (LUSC) samples. AZA up-regulates genes and pathways related to both innate and adaptive immunity and genes related to immune evasion in a several NSCLC lines. DNA hypermethylation and low expression of IRF7, an interferon transcription factor, tracks with this signature particularly in LUSC. In concert with these events, AZA up-regulates PD-L1 transcripts and protein, a key ligand-mediator of immune tolerance. Analysis of TCGA samples demonstrates that a significant proportion of primary NSCLC have low expression of AZA-induced immune genes, including PD-L1. We hypothesize that epigenetic therapy combined with blockade of immune checkpoints - in particular the PD-1/PD-L1 pathway - may augment response of NSCLC by shifting the balance between immune activation and immune inhibition, particularly in a subset of NSCLC with low expression of these pathways. Our studies define a biomarker strategy for response in a recently initiated trial to examine the potential of epigenetic therapy to sensitize patients with NSCLC to PD-1 immune checkpoint blockade

    Growth promoting activity of Pangasianodon hypophthalmus recombinant growth hormone expressed in Escherichia coli

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    Recombinant growth hormone of Pangasianodon hypophthalmus (rPhGH) was efficiently expressed in Escherichia coli BL 21 (DE3) cells. The expression vector pET-32a(+) was used to clone and express a 550 bp long cDNA fragment, which encodes the mature region of growth hormone. The rPhGH was expressed as a 6X HIS-tag fusion protein in E. coli upon induction by Isopropyl b-D-thiogalactoside, and formed insoluble inclusion bodies in the host cells. SDS-PAGE analysis indicated that the molecular weight of the fusion protein was about 23 kDa, which is comparable to the theoretical value of the mature growth hormone of the fish. The expressed protein was recovered by solubilising the inclusion bodies under denaturing conditions with urea and then the denatured proteins were refolded and purified on Ni-NTA column. The purified recombinant protein was confirmed by Western blot analysis using anti-His antibodies. Total yield of the refolded and purified protein was 20 mg l-1 of LB medium. Biological activity of the purified recombinant protein was determined in in vivo bioassay by its ability to promote growth in rohu (Labeo rohita) fingerlings, injected with three different concentrations of the hormone. A significant increase in growth was observed in rohu fingerlings administered with rPhGH at a dosage of 1.0 mg g body weight -1

    Cauchy's infinitesimals, his sum theorem, and foundational paradigms

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    Cauchy's sum theorem is a prototype of what is today a basic result on the convergence of a series of functions in undergraduate analysis. We seek to interpret Cauchy's proof, and discuss the related epistemological questions involved in comparing distinct interpretive paradigms. Cauchy's proof is often interpreted in the modern framework of a Weierstrassian paradigm. We analyze Cauchy's proof closely and show that it finds closer proxies in a different modern framework. Keywords: Cauchy's infinitesimal; sum theorem; quantifier alternation; uniform convergence; foundational paradigms.Comment: 42 pages; to appear in Foundations of Scienc
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