Studying the mode of action of phospholipid anit-tumor drugs using sacchromyces cerevisiae

Bibliography: p. 120-128Some pages are in colour

A Variable Speed Pumped Storage System Based on Droop-Fed Vector Control Strategy for Grid Frequency and AC-Bus Voltage Stability

Harnessing wind energy is the most rapidly growing amongst renewable energy sources. However, because of its intermittency in nature, wind power results in unfavorable influences on power system control, operation and stability. The voltage sag and flicker and grid frequency fluctuation are significant in this regard. To minimize the effect of wind power fluctuations and other contingencies on the grid frequency and AC-bus voltage, this paper presents a droop-fed vector control strategy based variable speed pumped storage (VSPS) system comprising the doubly fed induction machine. Modelling of the system is undertaken based on a phasor model technique. The case study is made by considering the droop-controlled VSPS plant in a grid containing conventional synchronous machines for hydropower and thermal power plants and an induction machine wind farm. The performance is validated and analyzed using a MATLAB/Simulink platform. The proposed droop-fed control model is compared with the conventional control strategy (without being droop-fed) and tested to wind power fluctuations, start-up transients, load variations and three-phase fault. The results show that the droop-fed vector control strategy of the VSPS plant achieves better dynamic and steady state controlling responses for grid frequency and AC-bus voltage in the power system than the conventional vector control scheme during wind power fluctuations and contingencies

Wind Power Fluctuation Compensation by Variable-Speed Pumped Storage Plant in a Grid Integrated System

Wind power technology is the fastest-growing technology for electrical energy production due to its potential characteristics. However, due to its randomness, it has an unnecessary impact on the operation and stability of the grid system. For example, the problem of power grid frequency fluctuation is more obvious. Fluctuations in frequency, in turn, can even affect the breakdown of power systems. To minimize these problems, a droop vector control strategy applied to variable-speed pumped storage (VSPS) systems can be implemented. This method should be used as a wind power fluctuation compensation solution in the wind farm grid-connected system. This chapter introduces the droop-fed direct power control strategy in a VSPS-wind farm-grid-connected system. The modeling of the system is based on the phasor model technique. The spectrum analysis method is used in the VSPS system to determine the dynamic performance of the power grid under wind power fluctuation compensation and emergencies and is verified on the MATLAB/Simulink platform. The results show that the spectrum analysis method is effective for determining the fluctuation and stability requirements of wind power in large power grids. The VSPS control strategy in the wind farm grid-connected integrated system achieves good power flow regulation and stable grid frequency, and the deviation is within an acceptable range

Effects of vitamin D on neonatal sepsis: A systematic review and meta-analysis

Vitamin D deficiency is a major public health concern of pregnant women and neonates worldwide, affecting more than half of neonates. Studies report inconsistent and inconclusive effects of vitamin D treatment on neonatal sepsis. This study aimed to provide conclusive evidence regarding the effect of maternal and cord blood vitamin D levels on neonatal sepsis. Data were retrieved from the electronic database (Web of Science, Scopus, CINAHL [EBSCOhost], ProQuest, EMBASE [Ovid], PubMed, Emcare, MEDLINE [Ovid], and gray literature sources [World cat, Mednar, Google scholar and Google]). Joanna Briggs Institute quality assessment tool was utilized for quality assessment while analysis was performed using Open Meta-analyst, Comprehensive Meta-analysis version 3.3.070, and Review Manager version 5.3 software. From the 18 studies included in the study, the overall prevalence of vitamin D deficiency among neonates was 61% (95% CI: 44.3, 77.7); 79.4% (95% CI: 71.6, 87.3) of neonates with sepsis were vitamin D deficient as were 43.7% (23.4, 63.9) of sepsis-free neonates. Neonates born from mothers with low vitamin D levels were at greater risk of developing neonatal sepsis with a weighed mean difference of −8.57 ng/ml (95% CI: −13.09, −4.05). Similarly, neonates with low cord vitamin D levels were at risk for neonatal sepsis with a mean difference of −8.78 ng/ml (95% CI:-11.58, −5.99). The incidence of EONS in full-term newborns was significantly associated with low maternal and cord blood vitamin D levels with weighed mean differences of −11.55ng/ml (95% CI: −17.63, −5.46) & −11.59 ng/ml (95% CI:-16.65, −6.53), respectively. Low levels of vitamin D both in the cord blood and maternal blood were significantly associated with neonatal sepsis. Hence, vitamin D supplementation for pregnant women and newborns could decrease neonatal sepsis

Alteration of plasma membrane organization by an anticancer lysophosphatidylcholine analogue induces intracellular acidification and internalization of plasma membrane transporters in yeast

The lysophosphatidylcholine analogue edelfosine is a potent antitumor lipid that targets cellular membranes. The underlying mechanisms leading to cell death remain controversial, although two cellular membranes have emerged as primary targets of edelfosine, the plasma membrane (PM) and the endoplasmic reticulum. In an effort to identify conditions that enhance or prevent the cytotoxic effect of edelfosine, we have conducted genome-wide surveys of edelfosine sensitivity and resistance in Saccharomyces cerevisiae presented in this work and the accompanying paper (Cuesta-Marbán, Á., Botet, J., Czyz, O., Cacharro, L. M., Gajate, C., Hornillos, V., Delgado, J., Zhang, H., Amat-Guerri, F., Acuña, A. U., McMaster, C. R., Revuelta, J. L., Zaremberg, V., and Mollinedo, F. (January 23, 2013) J. Biol. Chem. 288,), respectively. Our results point to maintenance of pH homeostasis as a major player in modulating susceptibility to edelfosine with the PM proton pump Pma1p playing a main role. We demonstrate that edelfosine alters PM organization and induces intracellular acidification. Significantly, we show that edelfosine selectively reduces lateral segregation of PM proteins like Pma1p and nutrient H+-symporters inducing their ubiquitination and internalization. The biology associated to the mode of action of edelfosine we have unveiled includes selective modification of lipid raft integrity altering pH homeostasis, which in turn regulates cell growth. © 2013 by The American Society for Biochemistry and Molecular Biology, Inc.This work was supported in part by a Natural Sciences and Engineering Research Council of Canada discovery grant, a seed grant from the University of Calgary, a Natural Sciences and Engineering Research Council of Canada University Faculty award (to V. Z.), Canadian Institutes of Health Research Grant 14124 (to C. R. M.), Spanish Ministerio de Economia y Competitividad Grants SAF2008-02251 and SAF2011-30518, Red Temática de Investigación Cooperativa en Cáncer, Instituto de Salud Carlos III, co-funded by the Fondo Europeo de Desarrollo Regional of the European Union Grants RD06/0020/1037 and RD12/0036/0065, European Community's Seventh Framework Programme FP7-2007-2013 Grant HEALTH-F2-2011-256986, (PANACREAS), and Junta de Castilla y León Grants CSI052A11-2 and CSI221A12-2 (to F. M.).Peer Reviewe

A Variable Speed Pumped Storage System Based on Droop-Fed Vector Control Strategy for Grid Frequency and AC-Bus Voltage Stability

Harnessing wind energy is the most rapidly growing amongst renewable energy sources. However, because of its intermittency in nature, wind power results in unfavorable influences on power system control, operation and stability. The voltage sag and flicker and grid frequency fluctuation are significant in this regard. To minimize the effect of wind power fluctuations and other contingencies on the grid frequency and AC-bus voltage, this paper presents a droop-fed vector control strategy based variable speed pumped storage (VSPS) system comprising the doubly fed induction machine. Modelling of the system is undertaken based on a phasor model technique. The case study is made by considering the droop-controlled VSPS plant in a grid containing conventional synchronous machines for hydropower and thermal power plants and an induction machine wind farm. The performance is validated and analyzed using a MATLAB/Simulink platform. The proposed droop-fed control model is compared with the conventional control strategy (without being droop-fed) and tested to wind power fluctuations, start-up transients, load variations and three-phase fault. The results show that the droop-fed vector control strategy of the VSPS plant achieves better dynamic and steady state controlling responses for grid frequency and AC-bus voltage in the power system than the conventional vector control scheme during wind power fluctuations and contingencies

Incidence and predictors of extrapulmonary tuberculosis among people living with Human Immunodeficiency Virus in Addis Ababa, Ethiopia: A retrospective cohort study.

BACKGROUND:Extrapulmonary tuberculosis is an emerging public health problem among HIV positives compared to the general population. This study aimed to assess the incidence and predictors of extrapulmonary tuberculosis among people living with HIV in selected health facilities in Addis Ababa, Ethiopia, from 01 January 2013 up to 31 December 2018. METHODS:A retrospective cohort study design was employed based on data collected from 566 HIV positive individuals. Data were entered using EpiInfo version 7.1 and analyzed by SPSS version 20. The incidence rate was determined per 100 person-years. Kaplan-Meier estimates used to estimate survivor and the hazard function, whereas log-rank tests used to compare survival curves and hazard across different categories. Cox proportional hazard model was used to identify the predictors and 95%CI of the hazard ratio were computed. P-value<0.05 in the multivariable analysis was considered statistically significant. RESULTS:Five hundred sixty-six HIV positive individuals were followed for 2140.08 person-years. Among them, 72 developed extrapulmonary tuberculosis that gives an incidence rate of 3.36/100 person-years (95%CI = 2.68-4.22). The most frequent forms of extrapulmonary tuberculosis were; lymph node tuberculosis (56%, 41) followed equally by pleural tuberculosis (15%, 11) and disseminated tuberculosis (15%, 11). The majority (70.83%) of the cases occurred within the first year of follow-up. In multivariable Cox regression analysis, baseline WHO stage III/IV (AHR = 2.720, 95%CI = 1.575-4.697), baseline CD4 count<50cells/μl (AHR = 4.073, 95%CI = 2.064-8.040), baseline CD4 count 50-200 cells/μl (AHR = 2.360, 95%CI = 1.314-4.239) and baseline Hgb<10 mg/dl (AHR = 1.979, 95%CI = 1.091-3.591) were the independent risk factors. While isoniazid prophylaxis (AHR = 0.232, 95%CI = 0.095-0.565) and taking antiretroviral drugs (AHR = 0.134, 95%CI = 0.075-0.238) had a protective benefit. CONCLUSION:Extrapulmonary tuberculosis co-infection was common among HIV positive individuals, and mostly occurred in those with advanced immune suppression. The risk decreases in those taking antiretroviral therapy and took isoniazid preventive treatment. Screening of HIV positives for extrapulmonary tuberculosis throughout their follow-up would be important

Incidence Density Rate of Neonatal Mortality and Predictors in Sub-Saharan Africa: A Systematic Review and Meta-Analysis

Background. Neonatal mortality in Sub-Saharan countries is remarkably high. Though there are inconsistent studies about the incidence density rate of neonatal mortalities (IDR) and predictors in Sub-Saharan Africa, they are inconclusive to policymakers and program planners. In this study, the IDR of neonatal mortalities and predictors was determined. Methods. Electronic databases (Web of Science, PubMed, EMBASE (Elsevier), Scopus, CINAHL (EBSCOhost), World Cat, Google Scholar, and Google) were explored. 20 out of 818 studies were included in this study. The IDRs and predictors of neonatal mortality were computed from studies conducted in survival analysis. Fixed and random effect models were used to compute pooled estimates. Subgroup and sensitivity analyses were performed. Results. Neonates were followed for a total of 1,095,611 neonate-days; 67142 neonate-days for neonates treated in neonatal intensive care units and 1,028,469 neonate-days for community-based studies. The IDRs of neonatal mortalities in neonatal intensive care units and in the community were 24.53 and 1.21 per 1000 person-days, respectively. The IDRs of early and late neonatal mortalities neonatal intensive care units were 22.51 and 5.09 per 1000 neonate-days, respectively. Likewise, the IDRs of early and late neonatal mortalities in the community were 0.85 and 0.31, respectively. Not initiating breastfeeding within one hour, multiple births, rural residence, maternal illness, low Apgar score, being preterm, sepsis, asphyxia, and respiratory distress syndrome were independent predictors of time to neonatal mortality in neonatal intensive care units and male gender, perceived small size, multiple births, and ANC were predictors of neonatal mortality in the community. Conclusion. The incidence density rate of neonatal mortality in Sub-Saharan Africa is significantly high. Multiple factors (neonatal and maternal) were found to be independent predictors. Strategies must be designed to address these predictors, and prospective studies could reveal other possible factors of neonatal mortalities