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Search Results: 1 - 10 of 417583 matches for " Joan J. E. Munissi "
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In Silico Evaluation of Anti-Malarial Agents from Hoslundia opposita as Inhibitors of Plasmodium falciparum Lactate Dehydrogenase (PfLDH) Enzyme  [PDF]
Daniel M. Shadrack, Stephen S. Nyandoro, Joan J. E. Munissi, Egid B. Mubofu
Computational Molecular Bioscience (CMB) , 2016, DOI: 10.4236/cmb.2016.62002
Abstract: Malaria has continued to be a health and economic problem in Africa and the world at large. Many anti-malarial drugs have been rendered ineffective due to the emergence of resistant strains of Plamodium falciparum. A key malaria parasite enzyme in glycolytic pathway, P. falciparum lactate dehydrogenase (PfLDH) is specially targeted for anti-malarial drugs development. Thus, the aim of this investigation was to determine the in silico inhibition effects of antimalarial compounds from Hoslundia opposita Vahl. namely hoslundin, hoslundal and hoslunddiol on PfLDH enzyme. The compounds were docked to the three-dimensional structure of PfLDH as enzyme using AutoDock Vina in PyRx virtual screening software. Binding affinity and position of the inhibitors were evaluated using PyMol software. The PfLDH enzyme showed two binding sites: the cofactors binding site (Site A) and secondary binding site (Site B). In the absence of the cofactor all ligands showed higher affinity than NADH, and were bound to the cofactors binding site (Site A). When docked in the presence of the cofactor, site B was the preferred binding site. Binding to cofactor site with higher binding energy than NADH suggests that these ligands could act as preferential competitive inhibitors of PfLDH. However, the binding to site B also suggests that they may be non-competitive allosteric inhibitors. Amino acid residues Gly99, Asn140, Phe100 and Thr97 were indicated to form hydrogen bonds with Hoslundin. Hoslunddiol showed hydrogen bonding with Thr97 and Met30, while Hoslundal formed hydrogen bond with Thr101 and Asn140.
Resolution Limits for Resonant Mems Sensors Based on Discrete Relay Feedback Techniques
J. Juillard,E. Colinet,M. Dominguez,Joan Pons,J. Ricart
Computer Science , 2007,
Abstract: This paper is devoted to the analysis of resonant MEMS sensors based on discrete relay feedback techniques. One drawback of such techniques is that some synchronization usually occurs between the discrete part and the continuous part of the system: this results in sensor responses that are very similar to the curves known as devil's staircases, i.e. the frequency does not vary smoothly with the sensor's input. The main contribution of this paper is a theoretical calculation of the resolution of such systems. The resolutions of two existing resonant MEMS architectures are then calculated and these results are discussed.
Influence of the Feedback Filter on the Response of the Pulsed Digital Oscillator
M. Dominguez,Joan Pons,J. Ricart,J. Juillard,E. Colinet
Computer Science , 2007,
Abstract: This paper introduces a new feedback topology for the Pulsed Digital Oscillator (PDO) and compares it to the classical topology. The `classic' or single feedback topology, introduced in previous works, shows a strong behavior dependence on the damping losses in the MEMS resonator. A new double feedback topology is introduced here in order to help solving this problem. Comparative discrete-time simulations and preliminary experimental measurements have been carried out for both topologies, showing how the new double feedback topology may increase PDO performance for some frequency ranges.
Adenocarcinomas after Prophylactic Surgery for Familial Adenomatous Polyposis  [PDF]
Joan C. Smith, Michael W. Sch?ffer, Billy R. Ballard, Duane T. Smoot, Alan J. Herline, Samuel E. Adunyah, Amosy E. M’Koma
Journal of Cancer Therapy (JCT) , 2013, DOI: 10.4236/jct.2013.41033

The incidence of familial adenomatous polyposis (FAP) is one in 7,000 to 12,000 live births. Virtually, all surgically untreated patients with FAP inevitably develop colorectal-cancer in their lifetime because they carry the adenomatous polyposis coli gene. Thus prophylactic proctocolectomy is indicated. Surgical treatment of FAP is still controversial. There are however, four surgical options: ileorectal anastomosis, restorative proctocolectomy with ileal pouch-anal anastomosis, proctocolectomy with ileostomy, and proctocolectomy with continent-ileostomy. Conventional proctocolectomy options largely lie between colectomy with ileorectal anastomosis or ileal pouch-anal anastomosis. Detractors of ileal pouch-anal anastomosis prefer ileorectal anastomosis because of better functional results and quality of life. The functional outcome of total colectomy with ileorectal anastomosis is undoubtedly far superior to that of the ileoanal pouch; however, the risk for rectal cancer is increased by 30%. Even after mucosectomy, inadvertent small mucosal residual islands remain. These residual islands carry the potential for the development of subsequent malignancy. We reviewed the literature (1975-2012) on the incidence, nature, and possible etiology of subsequent ileal-pouch and anal transit zone adenocarcinoma after prophylactic surgery procedure for FAP. To date there are 24 studies reporting 92 pouch-related cancers; 15 case reports, 4 prospective and 5 retrospective studies. Twenty three of 92 cancers (25%) developed in the pouch mucosa and 69 (75%) in anal transit zone (ATZ). Current recommendation for pouch surveillance and treatment are presented. Data suggest lifetime surveillance of these patients.

Reproductive Health Needs of Women Living with HIV/AIDS in Yaounde, Cameroon  [PDF]
Robinson E. Mbu, William A. Takang, Hortence J. Fouedjio, Ekane Joan, Flobert Y. Fouelifack, Florence N. Tumasang, Rebecca N. Tonye, Robert J. I. Leke
World Journal of AIDS (WJA) , 2014, DOI: 10.4236/wja.2014.41002

The population plagued with the HIV/AIDS pandemic in Cameroon is young, a generation that may desire or control fertility. For those who may become pregnant, the desire to have children may not be there. We carried out this study to look at the picture of the reproductive health needs of women living with HIV/AIDS in our setting. In this cross-sectional non-analytic design that lasted for three years, we employed both qualitative and quantitative methods to collect data from them after receiving ethical clearance (N221/CM/2009) from the National Ethics Committee. Consenting HIV infected women who were attending the “HIV Day Care” clinics and those who delivered and were in the post partum wards in four of our major hospitals in Yaounde were enrolled. Interviews were individualized. We used both CSPro version 4.1 and Statistical Package for Social Sciences (SPSS) version 19.0 softwares for data analysis. Four hundred and fifteen (415) women were enrolled; the mean age was 29 ± 7.8 years; the most represented age group was 24 -29 years. They were single (36.14%), well educated (5 out of 10 had attained university level of education), 61.20% revealed that their partners knew their HIV status, 82.4% believed that screening for cancer of the cervix was necessary for their status and 47.70% would want to be screened for some or all STIs. About 36.86% had the desire to have children, 57.1% of those who delivered did not plan to have the pregnancies out of which 82% would have wanted a modern method of contraception but did not have (82% unmet needs). Modern contraceptive use was associated with age and individual characteristics such as level of education. It was 64.34% among women who had secondary level of education and below as against 35.66% among those who had high school level of education and above. Contraceptive use was also high among women who were unmarried as against those who were married (89.64% vs 10.36%). The desire to have children decreased as age increased (43.85% vs 18.79%) and was lower among married women compared to those who were single (13.01% versus 49.64%). These women were found to have high unmet needs for modern contraception and showed interest in STIs and cervical cancer screening.

Fat intake and injury in female runners
Kristen E Gerlach, Harold W Burton, Joan M Dorn, John J Leddy, Peter J Horvath
Journal of the International Society of Sports Nutrition , 2008, DOI: 10.1186/1550-2783-5-1
Abstract: Eighty-six female subjects, running a minimum of 20 miles/week, completed a food frequency questionnaire and informed us about injury incidence over the next year.Injured runners had significantly lower intakes of total fat (63 ± 20 vs. 80 ± 50 g/d) and percentage of kilocalories from fat (27 ± 5 vs. 30 ± 8 %) compared with non-injured runners. A logistic regression analysis found that fat intake was the best dietary predictor, correctly identifying 64% of future injuries. Lower energy intake and lower energy availability approached, but did not reach, a significant association with overuse injury in this study.Fat intake is likely associated with injury risk in female runners. By documenting these associations, better strategies can be developed to reduce running injuries in women.The increased popularity of recreational and competitive running among females has led to an increased annual incidence of running-related injuries [1]. These injuries result from a complex interaction of female physiology with numerous risk factors that include sudden increases in training volume or intensity and a history of previous running injuries [1]. With the exception of calcium intake and incidence of stress fractures, though, nutrition as a contributing factor to running injuries has not been well-studied [2-4].Although not yet found to be associated with overuse injury, numerous studies have reported a large negative energy balance in female runners [5-8], with some controversy as to which factor is most important – overestimation of energy expenditure, underestimation of energy intake, enhanced metabolic efficiency, or a true chronic deficiency that results in hormone abnormalities and altered reproductive function [8]. At least one author [8] has argued that the phenomenon of chronic energy deficiency is very real and manifested by a spectrum of reproductive hormone abnormalities that range from the less severe ovarian dysfunctions of follicular/luteal suppression and anovula
Why People Do, or Do Not, Immediately Contact Emergency Medical Services following the Onset of Acute Stroke: Qualitative Interview Study
Joan E. Mackintosh, Madeleine J. Murtagh, Helen Rodgers, Richard G. Thomson, Gary A. Ford, Martin White
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0046124
Abstract: Objectives To identify the reasons why individuals contact, or delay contacting, emergency medical services in response to stroke symptoms. Design Qualitative interview study with a purposive sample of stroke patients and witnesses, selected according to method of accessing medical care and the time taken to do so. Data were analysed using the Framework approach. Setting Area covered by three acute stroke units in the north east of England. Participants Nineteen stroke patients and 26 witnesses who had called for help following the onset of stroke symptoms. Results Factors influencing who called emergency medical services and when they called included stroke severity, how people made sense of symptoms and their level of motivation to seek help. Fear of the consequences of stroke, including future dependence or disruption to family life, previous negative experience of hospitals, or involving a friend or relations in the decision to access medical services, all resulted in delayed admission. Lack of knowledge of stroke symptoms was also an important determinant. Perceptions of the remit of medical services were a major cause of delays in admission, with many people believing the most appropriate action was to telephone their GP. Variations in the response of primary care teams to acute stroke symptoms were also evident. Conclusions The factors influencing help-seeking decisions are complex. There remains a need to improve recognition by patients, witnesses and health care staff of the need to treat stroke as a medical emergency by calling emergency medical services, as well as increasing knowledge of symptoms of stroke among patients and potential witnesses. Fear, denial and reticence to impose on others hinders the process of seeking help and will need addressing specifically with appropriate interventions. Variability in how primary care services respond to stroke needs further investigation to inform interventions to promote best practice. Trial Registration UK Clinical Research Network UKCRN 6590
Mediator Subunit 12 Is Required for Neutrophil Development in Zebrafish
Maria-Cristina Keightley, Judith E. Layton, John W. Hayman, Joan K. Heath, Graham J. Lieschke
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0023845
Abstract: Hematopoiesis requires the spatiotemporal organization of regulatory factors to successfully orchestrate diverse lineage specificity from stem and progenitor cells. Med12 is a regulatory component of the large Mediator complex that enables contact between the general RNA polymerase II transcriptional machinery and enhancer bound regulatory factors. We have identified a new zebrafish med12 allele, syr, with a single missense mutation causing a valine to aspartic acid change at position 1046. Syr shows defects in hematopoiesis, which predominantly affect the myeloid lineage. Syr has identified a hematopoietic cell-specific requirement for Med12, suggesting a new role for this transcriptional regulator.
Temperature effect on tert-butyl alcohol (TBA) biodegradation kinetics in hyporheic zone soils
Mark H Greenwood, Ronald C Sims, Joan E McLean, William J Doucette
BioMedical Engineering OnLine , 2007, DOI: 10.1186/1475-925x-6-34
Abstract: Biodegradation of [U 14C] TBA was determined using hyporheic zone soil microcosms.First order mineralization rate constants of TBA at 5°C, 15°C and 25°C were 7.84 ± 0.14 × 10-3, 9.07 ± 0.09 × 10-3, and 15.3 ± 0.3 × 10-3 days-1, respectively (or 2.86 ± 0.05, 3.31 ± 0.03, 5.60 ± 0.14 years-1, respectively). Temperature had a statistically significant effect on the mineralization rates and was modelled using the Arrhenius equation with frequency factor (A) and activation energy (Ea) of 154 day-1 and 23,006 mol/J, respectively.Results of this study are the first to determine mineralization rates of TBA for different temperatures. The kinetic rates determined in this study can be used in groundwater fate and transport modelling of TBA at the Ronan, MT site and provide an estimate for TBA removal at other similar shallow aquifer sites and hyporheic zones as a function of seasonal change in temperature.The presence of methyl tert-butyl ether (MTBE) and the biodegradation intermediate tert-butyl alcohol (TBA) in shallow aquifer systems affected by seasonal low temperature groundwater (~5°C) have been widely reported [e.g. [1,2]]. In the past, the use of monitored natural attenuation (MNA) as a remediation alternative at MTBE and TBA contaminated sites in low temperature climates has had questionable utility because of the low rate of biodegradation anticipated to occur at low temperatures.Mesophilic microbial communities show optimum growth and biodegradation of substrates from 20°C to 40°C and become ineffective at 5°C [3,4]. Subsurface contaminant remediation with winter temperatures below 5°C would become temporarily depressed through part of the year since these systems are predominated by mesophilic microbial communities. However, MNA may remain an effective remediation year round if the microbial community is psychrotolerant, which is characteristic of having optimum temperature ranges from 15°C to 30°C and becoming ineffective at 0°C [4].Multiple studies have reporte
Phylogeography and sexual macrocyst formation in the social amoeba Dictyostelium giganteum
Natasha J Mehdiabadi, Marcus R Kronforst, David C Queller, Joan E Strassmann
BMC Evolutionary Biology , 2010, DOI: 10.1186/1471-2148-10-17
Abstract: We sequenced approximately 4,000 basepairs of the nuclear ribosomal DNA from 24 isolates collected from Texas, Michigan, Massachusetts, Virginia, and Wisconsin and identified 16 unique haplotypes. Analyses of the sequence data revealed very little genetic differentiation among isolates and no clear evidence of phylogenetic structure, although there was evidence for some genetic differentiation between the Massachusetts and Texas populations. These results suggest that sexual mating (macrocyst formation) is not likely to correlate with either genetic or geographical distance. To test this prediction, we performed 108 mating experiments and found no association between mating probability and genetic or geographical distance.D. giganteum isolates from across North America display little genetic variation, phylogeographic structure, and genetic differentiation among populations relative to the cryptic species observed within D. purpureum. Furthermore, variation that does exist does not predict the probability of mating among clones. These results have important implications for our understanding of speciation and social evolution in microbes.Studies of microbial biogeography and diversity provide a better understanding of the population structure, intraspecific genetic differentiation, and genetic diversity of these ubiquitous organisms [1,2]. Unlike plants and animals, free-living microorganisms are predicted to exhibit little population structure because their small size and large numbers make them easily dispersed [reviewed in [3,4]]. If microbes are characterized by high gene flow, then this should decrease microbial diversity across the landscape [5-7]. However, several studies have found that microorganisms can exhibit biogeographical patterns [e.g., [8-16]]. Distinguishing between these two alternative hypotheses is especially important for social microorganisms because population structure affects social interactions [17].Social amoebae live in decaying vegetati
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