850 research outputs found

    Protein kinase C in cellular transformation: a valid target for therapy?

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    The protein kinase C (PKC) family of serine/threonine protein kinases share structural homology, while exhibiting substantial functional diversity. PKC isoforms are ubiquitously expressed in tissues which makes it difficult to define roles for individual isoforms, with complexity compounded by the finding that PKC isoforms can co-operate with or antagonize other PKC family members. A number of studies suggest the involvement of PKC family members in regulating leukaemic cell survival and proliferation. Chronic lymphocytic leukaemia (CLL), the most common leukaemia in the Western world, exhibits dysregulated expression of PKC isoforms, with recent reports indicating that PKCβ and δ play a critical role in B-cell development, due to their ability to link the B-cell receptor (BCR) with downstream signalling pathways. Given the prognostic significance of the BCR in CLL, inhibition of these BCR/PKC-mediated signalling pathways is of therapeutic relevance. The present review discusses the emerging role of PKC isoforms in the pathophysiology of CLL and assesses approaches that have been undertaken to modulate PKC activity

    Research in Information Systems: Intra-Disciplinary and Inter-Disciplinary Approaches

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    The deep embeddedness of information systems (IS) in many areas of human activity poses a dual challenge to the IS discipline: advancing an expanding disciplinary boundary that includes an increasing set of IS topics; and engaging with other disciplines in order to understand IS-enabled phenomena. An inability to meet these challenges could lead to conceptually stunted development of the IS discipline, missed opportunities to inform other disciplines and a failure to effectively contribute to solving the pressing problems of our time. We undertook this study to investigate both how IS research has addressed these challenges in the past and how it can continue to do so in the future. Drawing on the concept of knowledge-materialization through knowledge-creating practice, and based on approaches for disciplinary and interdisciplinary knowledge creation, we theorize four different types of knowledge contribution that IS researchers can produce, encompassing both an intradisciplinary and an interdisciplinary view. We then analyze a wide-ranging sample of research studies published in 176 papers in the AIS basket of eight journals to investigate the nature of their contribution vis-à-vis these types. We find that the predominant types of knowledge contribution are intradisciplinary, with relatively few interdisciplinary contributions. Based on our analysis, we explain why each type of knowledge contribution is important to the IS discipline and provide guidance for IS scholars in planning their research strategies for these contributions. We comment on the implications of our study for IS scholars and for the vigor and growth of the IS discipline

    On non-LTE H<SUB>2</SUB><SUP>+</SUP> as missing solar opacity

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    A careful examination has revealed that use of incomplete reaction processes and incorrect rates have led Krishna Swamy and Stecher to overestimate the H2+ opacity by a factor of 104 at &#955; = 2000 &#197;. H2+ is not a significant source of opacity in the solar atmosphere

    Condensation and Evaporation of Mutually Repelling Particles :Steady states and limit cycles

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    We study condensation and evaporation of particles which repel each other, using a simple set of rules on a square lattice. Different results are obtained for a mobile and an immobile surface layer.A two point limit cycle is observed for high temperature and low pressure in both cases. Here the coverage oscillates between a high and a low value without ever reaching a steady state. The results for the immobile case depend in addition on the initial coverage.Comment: 8 pages, 3 figure

    Exploring combined effect of elevated CO2 and temperature on Fusarium wilt development of chickpea

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    Fusarium wilt (FW) caused by Fusarium oxysporum f. sp. ciceris (Foc) is one of the major diseases in chickpea. Under changing climatic scenario, elevated CO2 (eCO2) (550 and 700 ppm) and temperature (25°C, 30°C and 35°C) have potential impact on plant resistance mechanisms and pathogen virulence. Hence, the present study was aim to assess the impact of eCO2 and temperature on FW incidence and disease progression in two chickpea cultivars, JG 62 (susceptible) and WR 315 (resistant). Irrespective of temperature, the incubation period was delayed in eCO2 when compared to ambient. In case of combined effect, the maximum disease incidence was found in 30°C combined with 700 ppm as well as ambient CO2 conditions. To quantify the pathogen load and expression of several defence responsive genes in chickpea and virulence-related genes in Foc, qPCR study was employed. As compared to the eCO2, the expression of defence and virulence response genes in chickpea inoculated seedlings was highly up-regulated in ambient CO2 conditions irrespective of temperatures. The results suggested that among different defence-related genes studied, peroxidise gene was highly expressed in WR 315 cultivar, there by restricting the Foc colonization, by providing an evidence of efficient defense mechanism in the resistant cultivar. Moreover, in JG 62 the pathogenicity-causing secreted in xylem (SIX 14) gene was highly expressed as it mainly helps in colonization of Foc by defeating its defense in susceptible cultivar, which helps in providing more insights in understanding the compatible and incompatible interactions between chickpea and Fo

    Role of sonomammography and its diagnostic accuracy for evaluating benign and malignant breast lesions

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    Background: Mammography and ultrasound are the best-known techniques used for screening and diagnosis of breast cancer. This study evaluated the accuracy of sonomammography in diagnosing breast lesions, both benign and malignant separately and confirmation of the findings by histopathology.Methods: A prospective study was conducted for 18 months in women aged above 15 years with breast lesions or symptoms of breast diseases. The diagnosis protocol consisted of clinical breast examination, mammography, ultrasound and histopathological examination. Mammograms were interpreted according to the breast imaging reporting and data system (BI-RADS) diagnostic categories on a five-point scale. This was followed by ultrasound imaging of the breast and axilla with ultrasound-guided fine needle aspiration cytology (sonomammography-FNAC) from the breast lump.Results: Among the 52 patients, three patients were divorced, 40 were married and nine were unmarried. Eight had a history of oral contraceptive pills (OCP) use and one patient had a family history of breast lesions. The mammography report revealed 31 patients suspected to be malignant and 21 patients to be benign. According to the sonomammography report, 32 patients were suspected to be malignant while 20 patients were suspected to be benign. Correlation between mammography report, sonomammography report and grade versus histopathological finding also showed significance with p<0.0001.Conclusions: Sonomammography reveals good sensitivity and specificity for detecting all breast lesions. Hence it can be considered as a suitable means of investigation than mammography especially in patients less than 40 years of age.

    Improving fault ride-through of three phase voltage source inverter during symmetrical fault using DC link fault current limiter

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    The majority of distributed generation (DG) units utilize three phase voltage source inverter (VSI) to exchange electric power with the utility grid. The VSI employs semiconductor devices (SDs) with limited current withstand capabilities which are very vulnerable during grid faults. However, to ensure a secure and reliable operation of power systems at high penetration level of the DGs, most of the new grid codes worldwide require that the VSIs must have fault ride-through (FRT) capability. This paper presents a DC link fault current limiter (DLFCL) based VSI FRT scheme to improve its FRT capability. In the proposed scheme, the DLFCL is connected in series with the DC side of the VSI to limit the output current during symmetrical grid fault. The DLFCL does not have considerable effect on the VSI performance during the normal operation, whereas it limits the output current in all phases to the safe area operation of the SDs of the inverter. The effectiveness of the proposed scheme is validated through the simulation studies in PSCAD/EMTDC software

    Guaiacol as a new reagent for the spectrophotometric determination of uranium

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    Guiacol, i.e. o-hydroxyanisole, gives a distinct color reaction with U(VI) suitable for spectrophotometric determination of the metal. The complex formed in the reaction has an absorption maximum at 352 nm. Optimum pH for the color development ranges from 6.5 to 8.5. The molar absorptivity and Sandell's sensitivity of the method were found to be 3.75&#215;103 l.mol-1.cm-1 and 0.063 &#956;g.cm-2, respectively. Many anions and cations do not interfere up to 100 ppm. The method has been made very specific by selective extraction of U(VI) with TBP from a mixture of different cations and anions in the presence of 60% NH4NO3 as salting out agent followed by developing the color in the non-aqueous phase by adding quaiacol in methanol at pH 6.5 to 8.5 An amount as low as 30 &#956;g of uranium (VI) per 10 ml of the solution could be satisfactorily determined with an RSD of &#177;2.0%. The method was applied to rock samples after U(VI) had been extracted from a sample solution into 25% TBP in hexane. Results obtained by the new method compare very well with those of conventional fluorimetric and radiometric assays. The features of the method include excellent precision, rapidity, good selectivity, and ease of performance
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