The Malaria Parasitology

The microorganisms causing malaria are commonly referred to as malaria parasites, Plasmodium. In 1808 Laveran discovered plasmodium in blood in Algeria. There are nearly 120 species of plasmodia; 22 found in primate hosts, 19 found in rodents and bats and 70 found in birds and repliles

Fuzzy Logic Control Approach of a Maximum Power Point Employing SEPIC Converter for Standalone Photovoltaic System

AbstractThis paper presents a new fuzzy logic controller as a maximum power point tracker employing single-ended primary-inductor (SEPIC) converter. The new controller improves perturb and observe search method with rules to fuzzify and eliminate its drawbacks. An accurate and fast converging to maximum power point is offered by fuzzy logic tracker during both steady-state and varying weather conditions compared to conventional maximum power point tracking methods. The performance of the proposed maximum power point tracker is demonstrated in both simulation and experiment at different operating conditions

Effects of Seawater on Setting Time and Compressive Strength of Concretes with Different Richness

Water is one of the main constituents of concrete. Although many types of water exist, fresh water is the mostly used in concrete industry. Fresh water is expected to be in a great shortage by 2050 according to UN world water development report. Incorporating seawater in concrete mixture can help in the expected problem of scarcity of fresh water. Also, in many cases seawater may be the only available water especially in coastal regions. Many reports mention various possibilities of using seawater in concrete without detrimental effect on concrete properties. In this study another beneficial effect of seawater over tap water was concluded. Setting tests of cement paste mixed with seawater was determined using Vicat apparatus and compared to tap water. Compressive strength tests at the age of 28 days of Portland cement concretes with varied quantity of cement i.e. 300, 350, 400, 450, and 500 kg, and mixed with seawater was also performed and compared to tap water. The results show that seawater affects standard consistency of cement paste and two percent increase was required in order to attain the same consistency as tap water. It shows also seawater slightly accelerates initial setting of cement but the effect is not so pronounced so as to cause a trouble in concrete and final setting time almost remains unaltered. Compressive strength tests show an increase in concrete strength mixed with seawater for all tested mixtures and depending on quantity of cement. It also shows a beneficial effect of seawater on compressive strength of rich concrete with quantity of cement 450 and 500 kg over tap water. Doi: 10.28991/cej-2021-03091695 Full Text: PD

Impact of fill factor on input current ripple of photovoltaic system

This paper discusses the impact of fill factor on the input current ripple of the photovoltaic module and the loss effect on power extracted. Photovoltaic module's P-V curve produces exponential curve. The curvature of this curve indicates the fill factor of the particular cell; hence, by increasing the fill factor, the available extracted power increases. Yet, this paper states that losses due to photovoltaic current increases by increasing the fill factor

Molecular retention mechanisms of the G1 cyclin/Cdk complex in budding yeast

Budding yeast (Saccharomyces cerevisiae) cells coordinate cell growth and cell cycle progression essentially during G1, where they must reach a critical cell size to traverse Start and enter the cell cycle. The most upstream activator of Start is Cln3, a G1 cyclin that together with the cyclin-dependent kinase Cdc28 triggers a transcriptional wave that drives cell cycle entry. The Cln3 cyclin is a low abundant and very unstable protein whose levels respond very rapidly to nutritional changes. However, Cln3 expression is not sharply regulated through the cell cycle and it is already present in early G1 cells. Notably, most Cln3 is retained bound to the ER in early G1 with the assistance of Whi3, an RNA-binding protein that binds the CLN3 mRNA, and it is released in late G1 by Ydj1, a J-chaperone that might transmit growth capacity information to the cell cycle machinery. However, little is known on the molecular mechanisms that retain the Cdc28-C1n3 complex in the cytoplasm and how do these mechanisms transmit information of cell size to coordinate cell proliferation with cell growth. As Cdc28 is important for proper retention of Cln3 at the ER, we hypothesized that mutations weakening interactions to unknown ER retention factors would cause premature release of the Cdc28-C1n3 complex and, hence, a smaller cell size. This thesis describes the isolation and characterization of a CDC28 quintuple mutant, which we refer to as CDC28wee, that causes premature entry into the cell cycle and a small cell size. Next we used isobaric tags for relative and absolute quantitation (iTRAQ) to identify direct interactors with lower affinities for mutant Cdc28wee, aiming at the identification of proteins with key regulatory roles in the retention mechanism. Among the identified proteins we found Sr13, a protein of unknown function, here renamed as Whi7. Here we show that Whi7 acts as an inhibitor of Start, associates to the ER and contributes to efficient retention of the Cln3 cyclin, thus preventing its unscheduled accumulation in the nucleus. Our results demonstrate that Whi7 acts in a positive feedback loop to release the G1 Cdk¬cyclin complex and trigger Start once a critical size has been reached, thus uncovering a key nonlinear mechanism at the earliest known events of cell cycle entry. In addition to Whi7 we also identified Whi8, renamed here as Whi8, which is an RNA-binding protein present in both stress granules (SGs) and P bodies (PBs) with unknown biological function. We have found that Whi8 interacts with Cdc28 in vivo, binds and colocalizes with the CLN3 mRNA, and interacts with Whi3 in an RNA-dependent manner. Whi8-deficient cells showed a smaller budding cell size while, on the other hand, overexpression of Whi8 increased the budding volume. Cells lacking Whi8 were not capable of accumulating the CLN3 mRNA in SGs under stress conditions, and Cln3 synthesis remained high under glucose and nitrogen starvation, two environmental stress conditions that dramatically decrease Cln3 levels in the cell. Whi8 accumulation in SGs depended on an intrinsically disordered domain (IDD) identified at C-terminus of Whi8 and specific PKA phophosites. Our results suggest that Whi8 acts under stress as a safeguard that limits the influx of newly synthesized Cln3 (and likely other proteins) into the cell cycle machinery, by trapping the CLN3 mRNA in mRNA granules. Thus, we have found a unique target for signaling pathways that directly links stress response and cell cycle entry

DNA methylation of disrupted in schizophrenia 1 (disc1) gene in schizophrenia using methylight taqman assay

Introduction: Significant evidences from functional studies have shown that DISC1 gene has a role in the pathogenesis of schizophrenia, although the basis of the genetic defect has yet to be established. There has been a shift of emphasis from DISC1 gene variations to other genetic defect such as copy number and epigenetic, both of which have not been well investigated. Thus, the aim of this study is to examine the DNA methylation status of DISC1 gene in patients with schizophrenia. Methods: In this study, 239 subjects were included, 117 schizophrenia patients and 122 healthy controls. Genomic DNA was derived from peripheral blood and bisulfite converted. The DNA methylation level was quantitatively measured by Methylight Taqman analysis. Sociodemographic and the clinical parameters were noted. The severity of the clinical symptoms was assessed using Positive and Negative Syndrome Scale (PANSS). Results: The mean age and gender distribution of the study groups were similar. There were no significant differences in the methylation level of DISC1 between the patients and control groups When patients were compared by age, duration of illness, age at diagnosis, body mass index, smoking status, PANSS score, and types of antipsychotic treatment, the DNA methylation level of DISC1, did not show any significant difference (p>0.05). Conclusions: This study found no significant difference in methylation level of DISC1 gene between schizophrenia patients and healthy control. Therefore it is suggested that aberrant DNA methylation of DISC1 most probably does not contribute to the pathogenesis of schizophrenia

Source of stressors among medical students in Malaysia: a brief review

Introduction: This study aimed to identify the main sources of stressors among medical students in Malaysian public or private universities. Studies have shown that undergraduate students suffer from tremendous stress. Tertiary education has always been regarded as a highly stressful environment, especially for medical students. Method: A systematic literature review of the scientific articles on stressors in medical students were conducted. Various literature were searched through electronic databases, i.e. PubMed and SCOPUS published until December 2019 for articles bearing keywords; i) stress, ii) medical students, and iii) Malaysia. A total of eighteen articles were reviewed and data extracted. Results: The most common stressor was related to academic requirements that included tests and examinations. The other significant determinants consisted of psychological stress and personal factors. Conclusion: Studying medicine is highly stressful for undergraduate students. Although comparing various studies were difficult because of the differences in study design, instrument, number of stressors, etc.; this review gives the most recent published articles which included descriptive information that might be very useful for future research and management of stressors for medical students and education

DNA methylation of membrane-bound catechol-O-methyltransferase in Malaysian schizophrenia patients

AIM: This study examined catechol-O-methyltransferase (COMT) DNA methylation in the peripheral blood of schizophrenia patients and also in healthy controls to investigate its potential use as a peripheral biomarker of schizophrenia and its relations with the clinical variables of schizophrenia patients. METHODS: We examined the DNA methylation levels of COMT using genomic DNA from the peripheral blood of schizophrenia patients (n = 138) and healthy control participants (n = 132); all were Malaysian Malays. The extracted DNA was bisulfite converted, and the percentage methylation ratio value was calculated based on the results following a MethyLight protocol analysis. RESULTS: The percentage methylation ratio of COMT was lower in schizophrenia than it was in the healthy controls (P < 0.001) and was different between the body mass index (P = 0.003) and antipsychotic (P = 0.004) groups. The COMT DNA methylation rate was lower in patients receiving atypical antipsychotics (P = 0.004) and risperidone (P = 0.049) as compared to typical antipsychotics. The Excitement and Depressed subdomains of the Positive and Negative Syndrome Scale were inversely related (P < 0.001) and therefore predictors (Excitement: b = -11.396, t = -4.760, P < 0.001; Depressed: b = -7.789, t = -3.487, P = 0.001) of COMT DNA methylation. CONCLUSION: Our results suggested that the methylation level was affected by the severity of the clinical symptoms of schizophrenia and might also be influenced by pharmacological treatment. The epigenetic alteration of COMT in the peripheral blood could be a potential peripheral biomarker of schizophrenia