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Search Results: 1 - 10 of 3720 matches for " Joshua Barasa "
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Modeling and Simulation of an Isothermal Suspension Polymerization Reactor for PMMA Production Using Python  [PDF]
Aldo Okullo, Noah Tibasiima, Joshua Barasa
Advances in Chemical Engineering and Science (ACES) , 2017, DOI: 10.4236/aces.2017.74029
Abstract:
This paper presents the modeling and simulation of a suspension polymerization for methyl methacrylate in an isothermal reactor to produce poly methyl methacrylate using Python 3.5. The numeral solution to the stiff ordinary differential equations was performed by building a custom module which was used with the inbuilt NumPy and matplotlib modules that come with the Anaconda python distro. Python was used in order to obtain a realistic solution that considers the gel, glass and cage effects that affect the non-linear polymerization kinetics established in literature. The results showed that a maximum monomer conversion of about 92.8% at a minimum batch time of about 2.2 hours could be achieved at the specified conditions to obtain a polydisperse polymer with an index of 27. It is further concluded that Python can be employed to perform similar studies with equal success as any other programming language.
In vitro and in vivo antileishmanial efficacy of a combination therapy of diminazene and artesunate against Leishmania donovani in BALB/c mice
Mutiso, Joshua Muli;Macharia, John Chege;Barasa, Mustafa;Taracha, Evans;Bourdichon, Alain J.;Gicheru, Michael M.;
Revista do Instituto de Medicina Tropical de S?o Paulo , 2011, DOI: 10.1590/S0036-46652011000300003
Abstract: the in vitro and in vivo activity of diminazene (dim), artesunate (art) and combination of dim and art (dim-art) against leishmania donovani was compared to reference drug; amphotericin b. ic50 of dim-art was found to be 2.28 ± 0.24 μg/ml while those of dim and art were 9.16 ± 0.3 μg/ml and 4.64 ± 0.48 μg/ml respectively. the ic50 for amphot b was 0.16 ± 0.32 μg/ml against stationary-phase promastigotes. in vivo evaluation in the l. donovani balb/c mice model indicated that treatments with the combined drug therapy at doses of 12.5 mg/kg for 28 consecutive days significantly (p < 0.001) reduced parasite burden in the spleen as compared to the single drug treatments given at the same dosages. although parasite burden was slightly lower (p < 0.05) in the amphot b group than in the dim-art treatment group, the present study demonstrates the positive advantage and the potential use of the combined therapy of dim-art over the constituent drugs, dim or art when used alone. further evaluation is recommended to determine the most efficacious combination ratio of the two compounds.
In vitro and in vivo antileishmanial efficacy of a combination therapy of diminazene and artesunate against Leishmania donovani in BALB /c mice
Joshua Muli Mutiso,John Chege Macharia,Mustafa Barasa,Evans Taracha,Alain J. Bourdichon,Michael Muita Gicheru
Quantitative Biology , 2011, DOI: 10.1590/S0036-46652011000300003
Abstract: The in vitro and in vivo activity of diminazene (Dim), artesunate (Art) and combination of Dim and Art (Dim-Art) against Leishmania donovani was compared to reference drug; amphotericin B. IC50 of Dim-Art was found to be $2.28 \pm 0.24 \mu$ g/mL while those of Dim and Art were $9.16 \pm 0.3 \mu$ g/mL and $4.64 \pm 0.48 \mu$ g/mL respectively. The IC50 for Amphot B was $0.16 \pm 0.32 \mu$ g/mL against stationary-phase promastigotes. In vivo evaluation in the L. donovani BALB/c mice model indicated that treatments with the combined drug therapy at doses of 12.5 mg/kg for 28 consecutive days significantly ($p < 0.001$) reduced parasite burden in the spleen as compared to the single drug treatments given at the same dosages. Although parasite burden was slightly lower ($p < 0.05$) in the Amphot B group than in the Dim-Art treatment group, the present study demonstrates the positive advantage and the potential use of the combined therapy of Dim-Art over the constituent drugs, Dim or Art when used alone. Further evaluation is recommended to determine the most efficacious combination ratio of the two compounds.
True story about HIV: theory of viral sequestration and reserve infection
Barasa S
HIV/AIDS - Research and Palliative Care , 2011, DOI: http://dx.doi.org/10.2147/HIV.S26578
Abstract: ue story about HIV: theory of viral sequestration and reserve infection Expert Opinion (6274) Total Article Views Authors: Barasa S Video presented by Simon Barasa Views: 271 Published Date December 2011 Volume 2011:3 Pages 125 - 133 DOI: http://dx.doi.org/10.2147/HIV.S26578 Simon Situma Barasa Kenya Polytechnic University College, Nairobi, Kenya Abstract: Radical cure of infectious disease lies in the principle that the contagion is eliminated and its propagation within the body is stopped. By understanding the true mechanisms of human immunodeficiency virus (HIV) infection, effective cure is possible. Vertical research in HIV/acquired immunodeficiency syndrome (AIDS) has produced much advanced data about its nature without discovering a true cure, implying that the infective concept may have been missed. Overall, current interventions have had a significant impact on the pandemic, but they definitely have not achieved a cure. Given that modern research has already provided almost all significant data on HIV/AIDS, this inevitably means that understanding of the HIV and AIDS mechanism in the human body and population is less than sufficient. This paper advances a new concept using the available scientific data in an attempt to open a new frontier in HIV research.
True story about HIV: theory of viral sequestration and reserve infection
Barasa S
HIV/AIDS - Research and Palliative Care , 2011,
Abstract: Simon Situma BarasaKenya Polytechnic University College, Nairobi, KenyaAbstract: Radical cure of infectious disease lies in the principle that the contagion is eliminated and its propagation within the body is stopped. By understanding the true mechanisms of human immunodeficiency virus (HIV) infection, effective cure is possible. Vertical research in HIV/acquired immunodeficiency syndrome (AIDS) has produced much advanced data about its nature without discovering a true cure, implying that the infective concept may have been missed. Overall, current interventions have had a significant impact on the pandemic, but they definitely have not achieved a cure. Given that modern research has already provided almost all significant data on HIV/AIDS, this inevitably means that understanding of the HIV and AIDS mechanism in the human body and population is less than sufficient. This paper advances a new concept using the available scientific data in an attempt to open a new frontier in HIV research.Keywords: human immunodeficiency virus, HIV, acquired immunodeficiency syndrome, AIDS, viral sequestration
Plasmodium knowlesi H strain pregnancy malaria immune responses in olive baboons (Papio anubis)
Barasa Mustafa,Mwangi Irungu Michael,Mutiso Muli Joshua,Kagasi Ambogo Esther,Ozwara Suba Hastings,Gicheru Muita Michael
Quantitative Biology , 2012,
Abstract: Approximately 24 million pregnant women in Sub-Saharan Africa are at risk of suffering from pregnancy malaria complications. Mechanisms responsible for increased susceptibility to malaria in pregnant women are not fully understood. Baboons are susceptible to Plasmodium knowlesi and their reproductive physiology and host pathogen interactions are similar to those in humans, making them attractive for development as a model for studying mechanisms underlying pregnancy malaria. This study exploited the susceptibility of baboons to Plasmodium knowlesi infection to characterize cytokine and peripheral blood mononuclear cell recall proliferation responses underlying the pathogenesis of pregnancy malaria in baboons infected with Plasmodium knowlesi. The pregnancies of three time mated adult female baboons and their gestational levels were confirmed by ultrasonography. On the 150th day of gestation, the pregnant baboons together with four non pregnant controls were infected with Plasmodium knowlesi H strain parasites. Collection of peripheral sera, and mononuclear cells was then done on a weekly basis. Sera cytokine concentrations were measured by Enzyme Linked Immunosorbent Assay (ELISA) using respective enzyme conjugated antibodies. Peripheral blood mononuclear cell recall proliferation assays were also done on a weekly basis. Results indicate that pregnancy malaria in this model is associated with suppression of interferon gamma and interleukin 6 (IL-6) responses. Tumour necrosis factor alpha responses were upregulated while IL-4, IL-12 and recall proliferation responses were not different from controls. These data to a great extent are consistent with some findings from human studies, showing the feasibility of this model for studying mechanisms underlying pregnancy malaria.
Overcoming Barriers to Contraceptive Uptake among Adolescents: The Case of Kiambu County, Kenya  [PDF]
Mary Murigi, Dennis Butto, Sammy Barasa, Evah Maina, Bonnie Munyalo
Journal of Biosciences and Medicines (JBM) , 2016, DOI: 10.4236/jbm.2016.49001
Abstract: Despite high sexual activity among adolescent girls in Kenya, contraceptive uptake is very low with only about 26 percent sexually active adolescent girls currently using a contraceptive method. This exposes them to HIV infections and unplanned pregnancies which consequently lead to school dropouts, unsafe abortions, and lack of employment opportunities. This cross-sectional study aimed at assessing the utilization of contraceptives among secondary school adolescent girls in Karuri Town Council, Kiambu County. Overall, 421 girls aged between 13.0 to 19.0 years took part in the study. Findings showed that despite majority (77.5%) of the adolescent girls having had sexual debut by the age of 15 years, contraceptive utilization was very low at 43%. The results revealed that age of the adolescent, knowledge of contraceptives options, perception and accessibility of the contraceptives had positive significant effect on contraceptive utilization. Adolescents aged 18 years and above were more likely to utilize contraceptives as compared to those of a lesser age (p ≤ 0.001; OR: 9.870 (95% CI: 3.781 - 25.763)). Those with knowledge on contraceptives were OR 3.2 times more likely to use contraceptives (p = 0.025), similarly, accessibility was significantly associated with increased contraceptive utilization (p = 0.34, 95% CI: 1.054 - 4.187). Adolescents who perceived use of contraceptives as wise were more likely to use a contraceptive than those of a divergent opinion (OR: 2.053 (95% CI: 1.024 - 4.115), p = 0.041). This revealed that high level of knowledge on contraceptives did not always amount to practice. There is therefore a need to develop age specific reproductive health messages to guide school education curriculum as well as parent or guardian-child communication.
Molecular Footprint of Kenya’s Gene Bank Repositories Based on the cp-Genome Signatures  [PDF]
Okoth Patrick, Muoma John, Omayio Dennis, Barasa Mustafa, Angienda Paul
American Journal of Molecular Biology (AJMB) , 2018, DOI: 10.4236/ajmb.2018.84019
Abstract: While the mutational processes that subsume biological diversity can be revealed in great detail through phylogenetic inferencing using plastid markers, few studies document their use. Accurate phylogenic inference can provide a framework for addressing a host of important evolutionary questions including a context to reconstruct molecular evolution of an organism. Despite the obvious utility of plastid markers in illuminating biological enquiry, many important questions still abound. The use of cp-DNA gene sequence data for phylogenetic inference can have an enormous impact on plant phylogenetics and systematics. The repertoire of genetic diversity of Kenya’s Gene Bank repositories can be explored based on cp-genome signatures. This is because cp-DNA-based mutational changes are an important additional tool to the previous evidence available on plant evolution yet to be explored in biodiversity studies in Kenya. Taken together, these evolutionary changes can inspire development of realistic algorithms for phylogenetic inferencing based on molecular data. Phylogenetic reconstructions are at the very core of molecular evolution. Comparative sequence analyses of plastid markers can have utility beyond the study of phylogeny. The pattern of nucleotide substitution observed over evolutionary time can reflect functional constraints imposed due to natural selection. In line with this, it is possible to detect subtle anatomical variations associated with small fitness effects that can account for genetic diversity at varietal level. The lack of sequence information in Kenyan cowpea has limited the robust advancement of molecular markers use in dissecting diversity based on the putative plastid markers[1]. The present study sought to generate and upscale novel technologies such as genomics, DNA barcoding and bio-informatics in understanding molecular diversity of cowpea accessions from the Gene Bank of Kenya and ecotypes. A total of 298 sequences of cowpea germplasm conserved as in
Blunted IL17/IL22 and Pro-Inflammatory Cytokine Responses in the Genital Tract and Blood of HIV-Exposed, Seronegative Female Sex Workers in Kenya
Duncan Chege, Yijie Chai, Sanja Huibner, Taylor Kain, Charles Wachihi, Makubo Kimani, Samson Barasa, Lyle R. McKinnon, Festus K. Muriuki, Anthony Kariri, Walter Jaoko, Omu Anzala, Joshua Kimani, T. Blake Ball, Francis A. Plummer, Rupert Kaul
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0043670
Abstract: Background Identifying the immune correlates of reduced susceptibility to HIV remains a key goal for the HIV vaccine field, and individuals who are HIV-exposed, seronegative (HESN) may offer important clues. Reduced systemic immune activation has been described in HESN individuals. Conversely, pro-inflammatory T cell subsets, particularly CD4+ T cells producing the cytokine IL17 (Th17 cells), may represent a highly susceptible target for HIV infection after sexual exposure. Therefore, we characterized the cellular pro-inflammatory and IL17/IL22 cytokine immune milieu in the genital mucosa and blood of HESN female sex workers (FSWs). Methods and Results Blinded lab personnel characterized basal and mitogen-induced gene and cytokine immune responses in the cervix and blood of HESN FSWs (n = 116) and non-FSW controls (n = 17) using qPCR and ELISA. IL17 and IL22 production was significantly reduced in both the cervix and blood of HESNs, both in resting cells and after mitogen stimulation. In addition, HESN participants demonstrated blunted production of both pro-inflammatory cytokines and β-chemokines. Discussion and Conclusions We conclude that HIV exposure without infection was associated with blunted IL17/IL22 and pro-inflammatory responses, both systemically and at the site of mucosal HIV exposure. It will be important for further studies to examine the causal nature of the association and to define the cell subsets responsible for these differences.
The HAART cell phone adherence trial (WelTel Kenya1): a randomized controlled trial protocol
Richard T Lester, Edward J Mills, Antony Kariri, Paul Ritvo, Michael Chung, William Jack, James Habyarimana, Sarah Karanja, Samson Barasa, Rosemary Nguti, Benson Estambale, Elizabeth Ngugi, T Blake Ball, Lehana Thabane, Joshua Kimani, Lawrence Gelmon, Marta Ackers, Francis A Plummer
Trials , 2009, DOI: 10.1186/1745-6215-10-87
Abstract: A multi-site randomized controlled open-label trial. A central randomization centre provided opaque envelopes to allocate treatments. Patients initiating ART at three comprehensive care clinics in Kenya will be randomized to receive either a structured weekly SMS ('short message system' or text message) slogan (the intervention) or current standard of care support mechanisms alone (the control). Our hypothesis is that using a structured mobile phone protocol to keep in touch with patients will improve adherence to ART and other patient outcomes. Participants are evaluated at baseline, and then at six and twelve months after initiating ART. The care providers keep a weekly study log of all phone based communications with study participants.Primary outcomes are self-reported adherence to ART and suppression of HIV viral load at twelve months scheduled follow-up. Secondary outcomes are improvements in health, quality of life, social and economic factors, and retention on ART. Primary analysis is by 'intention-to-treat'. Sensitivity analysis will be used to assess per-protocol effects. Analysis of covariates will be undertaken to determine factors that contribute or deter from expected and determined outcomes.This study protocol tests whether a novel structured mobile phone intervention can positively contribute to ART management in a resource-limited setting.Trial Registration Number: NCT00830622The most important factor for sustainable treatment of HIV/AIDS for individuals and programs globally is highly consistent use of highly active antiretroviral therapy (ART). For patients, this means adhering to daily or twice daily medication schedules, typically at a minimum of at least 95% of the time, and for programs this means supporting and monitoring patients to achieve those goals.[1] The World Health Organization and UNAIDS have outlined ambitious goals of universal access to those in need among the 28 million people infected with HIV globally, and include a directive
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