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Protecting Triazabutadienes To Afford Acid Resistance

Lindsay E. Guzman, Flora W. Kimani, John C. Jewett
2016 ChemBioChem  
Recent work on triazabutadienes has shown that they possess the ability to release aryl diazonium ions under exceptionally mild acidic conditions. There are instances that require that this release be prevented or minimized. Accordingly, a base-labile protection strategy for the triazabutadiene is presented allowing for enhanced synthetic and practical utility of the triazabutadiene. Herein the effects of steric and electronic factors in the rate of removal are discussed. Finally, the
more » ... diene protection is shown to be compatible with the traditional acid-labile protection strategy used in solid phase peptide synthesis. Graphical Abstract Triazabutadienes can be used as masked tyrosine-selective aryl diazonium ions. We report a baselabile protecting group for triazabutadienes to prevent the acid-dependent release of aryl diazonium ions. The pH-dependent deprotection rate constants are reported with electronic and steric perturbations to the system, enabling widespread utility of triazabutadienes in chemical biology. Keywords protecting group; aryl diazonium ion; rate of hydrolysis; acid / base chemistry Chemical reactions that proceed with predictable outcomes in aqueous media are of interest to the field of bioconjugation. Selectivity is both essential and challenging as sample complexity increases. The selective reactivity of aryl diazonium ions with protein side chains has been known for over 100 years, [1] but yet their utility remains untapped relative
doi:10.1002/cbic.201600517 pmid:27662242 pmcid:PMC5170869 fatcat:sr3lkgzl65eu7lr2xspxfwt7z4

Reduced Cellular Susceptibility to In Vitro HIV Infection Is Associated with CD4+ T Cell Quiescence

Catherine M. Card, W. John Rutherford, Suzie Ramdahin, Xiaojian Yao, Makobu Kimani, Charles Wachihi, Joshua Kimani, Francis A. Plummer, T. Blake Ball, Keith R. Fowke, Alan Landay
2012 PLoS ONE  
HIV preferentially establishes productive infection in activated CD4+ T cells. Since proportions of activated CD4+ T cells vary between individuals, this study aimed to determine if individuals with a greater proportion of activated CD4+ T cells would be more susceptible to in vitro HIV infection. Methodology/Principal Findings: Unstimulated peripheral blood mononuclear cells (PBMC) from various donors were inoculated with HIV ML1956 in vitro. HIV replication was evaluated by HIV p24 ELISA of
more » ... lture supernatants and intracellular staining for HIV p24, which was detected by flow cytometry. Baseline T cell phenotypes and infected cell phenotypes were also evaluated by flow cytometry. Ex vivo phenotyping at the time of blood draw showed that elevated T cell activation and reduced Tregs were associated with increased cellular susceptibility to in vitro infection. Furthermore, the infected CD4+ T cell population was enriched for activated cells. Conclusion/Significance: These data suggest that CD4+ T cell quiescence provides an environment less conducive to the establishment of HIV infection by limiting the pool of activated target cells.
doi:10.1371/journal.pone.0045911 pmid:23029309 pmcid:PMC3448692 fatcat:asuurzfymzad3hbvvyzzgt4kna

Understanding and comparing the globe-trotting cancer patient with the locally managed patient: A case control study [article]

Mary W Wangai, Frederick Kimani Wangai, Francis John Njiiri, John Kinuthia, Enan Ngugi Wangai, Catherine Nyongesa, Paul Wangai
2022 medRxiv   pre-print
Medical tourism is characterized by people seeking treatment abroad for various medical conditions due to varied reasons, many of whom benefit from specialized care for non-communicable diseases. Conversely, there are associated negative effects such as medical complications and weakened health systems. Currently, there is paucity of scientific evidence on factors influencing seeking treatment benefits abroad. This study sought to compare patient-related factors associated with choice of cancer
more » ... treatment center locally or abroad, to understand reasons for seeking treatment outside Kenya. Materials and Methods As a case-control study, 254 cancer patients were randomly sampled to compare responses from those who chose to receive treatment abroad or in Kenya. The cases were recruited from Ministry of Health while the controls from Kenyatta National Hospital and Texas Cancer Center. Data was analyzed using SPSS Software Version 21. Descriptive statistics, bivariate and multiple logistic regression analysis was carried out. Level of significance was set at 5%. Results Out of 254 respondents, 174 (69.5%) were treated for cancer in Kenya and 80 (31.5%) in India. We found that cost effectiveness was a significant factor for over 73% of all respondents. The study revealed independent predictors for seeking treatment in India were: monthly income higher than US$ 250; every additional month from diagnosis increased likelihood by 1.16 times; physician advice (Odds Ratio(OR) 66; 95% Confidence Interval(CI) 7.9 -552.9); friends and family (OR 42; 95% CI 7.07-248.6); and perception of better quality of care (OR 22.5; 95% CI 2.2-230.6). Conclusion Reasons patients with cancer sought treatment in India are multifactorial. Several of these can be addressed to reverse out-ward bound medical tourism and position Kenya to be a regional hub as per Kenyas development blueprint. It will require strengthening the health system accordingly and sensitizing the medical fraternity and general public on the same.
doi:10.1101/2022.04.13.22273435 fatcat:t6em2ynlpjfqnbzdjq3j5xm6am


Robert Kariuki Waithaka, John G. Kimani
2021 Global Journal of Purchasing and Procurement Management  
Purpose: the purpose of the study is to establish the influence of electronic procurement practices on supply chain performance. Methodology: The researcher employed a method of reviewing desktop literature. To assess the feasibility of the subject for testing, three processing stages were applied on the subject under review. This was the first step of the original identification of all papers based on the effect of electronic sourcing activities on the efficiency of the supply chain. A second
more » ... uest covered fully available literature on the issue of e-procurement processes and efficiency of the supply chain. The third stage included the collection of journals that were freely available. The researcher arrived at 12 papers that were relevant for review after an in-depth quest into the top key terms (e-procurement processes, supply chain management, performance). Findings: Procurement performance is the backbone of an organization success since it contributes to competitive purchase and acquisition of quality goods that puts the organization products or services in the competitive edge in the market. In the analysis of the use of e-procurement on performance of the procurement functions of county governments in Kenya, the results revealed that e-procurement is positively related with performance of supply chain function of County Governments in Kenya. Unique contribution to theory, practice and policy: The study therefore recommended that the Government come up with policies on adoption of e-procurement practices and provide critical resources and leadership in adoption of e-procurement. It is recommended that in order to achieve maximum benefits of reduced order processing time, reduced costs, reduced human errors and improved delivery, management should enhance electronic system and insist on all orders being processed electronically.
doi:10.47604/gjppm.1200 fatcat:tpknqjirmbbypiq6azbwfrzqb4

Genotype environment interactions for grain yield in rice under no drought and drought conditions

N. Musila Ruth, Sibiya Julia, Derera John, M. Kimani John, Tongoona Pangirayi
2017 African Journal of Plant Science  
Environments in sub-Saharan Africa fluctuate considerably across sites and seasons. This suggests the importance of assessing genotype x environment interaction (GEI) in cultivar development. The objective of this study was to estimate the magnitude of GEI for rice grain yield and identify high yielding and stable rice genotypes. Fifty six genotypes including 45 F 3 rice populations, their 10 parents and one check were evaluated in 7 x 8 alpha lattice design with two replications under three no
more » ... drought and one random managed drought stress condition at reproductive growth stage at three sites in coast region of Kenya. The additive main effects and multiplicative interaction (AMMI) analysis and genotype plus genotype x environment interaction (GGE) biplot analysis were used to measure grain yield stability of the 45 F 3 populations and their 10 parents. Ranking of the genotypes changed in each environment and three mega environments were identified revealing a crossover type of GEI. The genotypes G39 (Luyin 46 x IR74371-54-1-1) and G40 (NERICA-L-25 x IR55423-01) were the most stable high yielding genotypes. These were identified as candidates with general adaption for advancement to homozygozity simultaneously selecting within each population good performing pure lines for release in the region. Key words: Additive main effects and multiplicative interaction (AMMI), genotype x environment interactions, genotype plus genotype x environment interaction (GGE) biplot, rice, yield stability.
doi:10.5897/ajps2016.1441 fatcat:yzp6okwytvcnxlxxfbcpcimhua

Depressive symptoms and problematic alcohol and other substance use in 1476 gay, bisexual, and other MSM at three research sites in Kenya

Christine Korhonen, Makobu Kimani, Elizabeth Wahome, Fredrick Otieno, Duncan Okall, Robert C. Bailey, Gary W. Harper, Robert R. Lorway, Monika Doshi, John Mathenge, Joshua Kimani, Eduard J. Sanders (+1 others)
2018 AIDS (London)  
doi:10.1097/qad.0000000000001847 pmid:29734218 pmcid:PMC6150184 fatcat:m3ij3yesxfa4hjsc264gbebzoe


John Githii Kimani, Dr. George Ruigu Ruigu
2017 Journal of agricultural policy  
Purpose: The purpose of the study was to assess the impact of research and development investment/expenditure on the agricultural sector performance in Kenya.Methodology: The study took the peoples impact assessment direction. The data for this study was collected from various government agencies such as KARI, ASTI, Kenya Agricultural Sector Data compendium website, FAOSTAT, World Bank among others. Co-integration and error correction modeling methods were used in analyzing the data for this
more » ... dy.Results: Co-integration results for both the parsimonious and non-parsimonious model indicated that that there is a long-run relationship among the variables in the agriculture performance in Kenya. Further, findings in this study indicated that the variables under study were insignificant determinants of the long run Total Factor Productivity of the agricultural sector. Meanwhile, Trade openness was the only significant determinant of the short run agricultural Total Factor Productivity.Unique Contribution to Policy and Practice: This study recommends the institutionalization of policies aimed at ensuring interaction between the various stakeholders in the agricultural sectors. This interaction will ensure that resources are better allocated to reduce duplication of research and dissemination activities. In addition, greater collaboration among the stakeholders will promote and strengthen the connection between research, policy and the application of research findings. The study further advocates that the government should follow a trade liberazation oriented approach to the agricultural sector as opposed to a trade tightening approach.
doi:10.47941/jap.161 fatcat:bhjjrx7awvfvxnjo3bzlmgktfm

Use of insecticide-treated clothes for personal protection against malaria: a community trial

Elizabeth W Kimani, John M Vulule, Isabel W Kuria, Fredrick Mugisha
2006 Malaria Journal  
The study sought to determine the effect of using insecticide-treated clothes (ITCs) on personal protection against malaria infection. The specific objectives were to determine the effect of using ITCs on the rate of infection with malaria parasites and the effect on indoor mosquito density. Methods: This study was done in Dadaab refugee camps, North Eastern Province Kenya between April and August 2002, and involved a total of 198 participants, all refugees of Somali origin. The participants
more » ... e selected through multi-stage cluster sampling. Half of the participants (treatment group) had their personal clothes worn on a daily basis (Diras, Saris, Jalbaabs, Ma'awis and shirts) and their bedding (sheets and blankets) treated with insecticide (permethrin). The other half (comparison group) had their clothes treated with placebo (plain water). Indoor mosquito density was determined from twelve households belonging to the participants; six in the treatment block and six in the comparison block. During pre-test and post-test, laboratory analysis of blood samples was done, indoor mosquito density determined and questionnaires administered. Using STATA statistical package, tests for significant difference between the two groups were conducted. Results: Use of ITCs reduced both malaria infection rates and indoor mosquito density significantly. The odds of malaria infection in the intervention group were reduced by about 70 percent. The idea of using ITCs for malaria infection control was easily accepted among the refugees and they considered it beneficial. No side effects related to use of the ITCs were observed from the participants. Conclusion: The use of ITCs reduces malaria infection rate and has potential as an appropriate method of malaria control. It is recommended, therefore, that this strategy be considered for use among poor communities like slum dwellers and other underprivileged communities, such as street children and refugees, especially during an influx to malaria-prone regions. Further research on cost-effectiveness and sustainability of this strategy is worthwhile.
doi:10.1186/1475-2875-5-63 pmid:16872529 pmcid:PMC1555594 fatcat:5altpsoyirdqtoxq7ryjzdgleu

Online Requirements and Portal Design for Female University Science and Technology Students in Kenya [chapter]

Stephen Kimani, Eunice Njeri, John Njue
2013 Lecture Notes in Computer Science  
In science and technology (S&T) career progression, women drop out at virtually every step until extremely few are found in positions of influence and recognition. Although this is a global problem, it is even more critical in Africa. The number of female university S&T students in Africa has remained low for the past about three decades. There is thus a dire need to encourage/support such students especially in African countries, including Kenya. Online portals have the potential to
more » ... pport Kenyan female university S&T students. It is however critical to understand the characteristics and requirements of these students. While there exists literature on the differences between online female users and male users, women in S&T in African countries (including Kenya) face rather unique challenges. This paper reports a study that indicates the characteristics and online requirements of Kenyan female university S&T students, and then describes a corresponding online portal design.
doi:10.1007/978-3-642-40498-6_31 fatcat:t6tchjagonhlpedmgv2j4y5oje


Kengo Danda, John Kimani, Kyung Ho Kang
2022 International journal of agriculture  
(2010) and Kimani et al. (2011) .  ...  Generally in the rice subsector, lack of quality seed that has undergone rigorous production system is lacking (Kimani, 2010 and Musila, 2015) and thus there is urgent need to scale up availability of  ... 
doi:10.47604/ija.1487 fatcat:wqy4qtvdtfch7ki26ncmgf7sia


Robert Kariuki Waithaka, John G. Kimani
2021 Global Journal of Purchasing and Procurement Management  
Purpose: This study proposes sought to determine factors influencing the adoption of e-procurement practices. Methodology: The paper used a desk study review methodology where relevant empirical literature was reviewed to identify main themes and to extract knowledge gaps. The study adopted a desktop literature review method (desk study). This involved an in-depth review of studies related to factors influencing the adoption of e-procurement practices. The search was done generally by searching
more » ... the articles in the Article title, abstract, keywords. A second search involved fully available publications on the subject of e-procurement practices. The third step involved the selection of fully accessible publications. The drawing and interpretation of research findings and sense which is not a quantitative impact evaluation, was important in this context, which implies that qualitative and thematic analysis was most suitable in this study. Findings: From the study, it was noted that E-procurement has not been fully adopted by all the agencies. Further, E-security, staffing, user acceptance and top management support were the factors that were found to be influencing adoption of e-procurement. Top management support and E-security are the major influence of E-procurement adoption especially in the public sector. Unique contribution to theory, practice and policy: The study recommended that Top management support among the organizations should set goals, strategies and baselines that are necessary for the adoption of the E-procurement and follow up to ensure implementation. The study also recommended that due to the sensitivity of the data and the legal nature of orders and payments, security of data should be enhanced. Organizations should create personalized technology systems that create a demand adaptation of ICT at every level of the organizational operations
doi:10.47604/gjppm.1199 fatcat:j45vixdc3vfgxpvz5ifdjupvsu

Locating irregularly shaped clusters of infection intensity

Niko Yiannakoulias, Shona Wilson, H. Curtis Kariuki, Joseph K. Mwatha, John H. Ouma, Eric Muchiri, Gachuhi Kimani, Birgitte J. Vennervald, David W. Dunne
2010 Geospatial Health  
Patterns of disease may take on irregular geographic shapes, especially when features of the physical environment influence risk. Identifying these patterns can be important for planning, and also identifying new environmental or social factors associated with high or low risk of illness. Until recently, cluster detection methods were limited in their ability to detect irregular spatial patterns, and limited to finding clusters that were roughly circular in shape. This approach has less power
more » ... detect irregularly-shaped, yet important spatial anomalies, particularly at high spatial resolutions. We employ a new method of finding irregularly-shaped spatial clusters at micro-geographical scales using both simulated and real data on Schistosoma mansoni and hookworm infection intensities. This method, which we refer to as the "greedy growth scan", is a modification of the spatial scan method for cluster detection. Real data are based on samples of hookworm and S. mansoni from Kitengei, Makueni district, Kenya. Our analysis of simulated data shows how methods able to find irregular shapes are more likely to identify clusters along rivers than methods constrained to fixed geometries. Our analysis of infection intensity identifies two small areas within the study region in which infection intensity is elevated, possibly due to local features of the physical or social environment. Collectively, our results show that the "greedy growth scan" is a suitable method for exploratory geographical analysis of infection intensity data when irregular shapes are suspected, especially at micro-geographical scales.
doi:10.4081/gh.2010.200 pmid:20503188 fatcat:j77r2zvx7vdqzeen55mcbcdhtu

Engaging sophomores in embedded design using robotics

Amir Momeni, Fritz Previlon, Agamemnon Despopoulos, Gunar Schirner, John Kimani, David Kaeli
2015 Proceedings of the Workshop on Computer Architecture Education - WCAE '15  
The material covered in a typical Computer Engineering class tends to be heavily focused on a single subject area. Students often struggle to see how different subjects are interrelated or how they can be combined to address a wider range of problems.
doi:10.1145/2795122.2795131 dblp:conf/wcae/MomeniPDSKK15 fatcat:grlcsxanqrcq3n25zcbdkxupou

Have power sector reforms increased access to electricity among the poor in East Africa?

Stephen Karekezi, John Kimani
2004 Energy for Sustainable Development  
The article focuses on power sector reforms in East Africa and attempts to assess their impact on the poor. Specifically, the article examines the extent to which the amendment of the Electricity Act -a key pillar of power sector reform -has influenced the electrification of the poor. The article is based on the case studies of Kenya and Uganda undertaken under the auspices of the Global Network on Energy for Sustainable Development's "Energy Access" Working Group. Poverty levels in the East
more » ... ican sub-region are very high, particularly in the rural areas. For instance, in both Kenya and Uganda, virtually the entire (100%) 1 rural population falls under the US$ 2 per capita per day poverty threshold. Consequently, the rural population has been used as a proxy for the poor in this article. This article reveals that only 1% of the rural households in Kenya and Uganda has access to electricity -implying that very few of the poor are electrified. The two case studies demonstrate key shortfalls in the provision of electricity to the poor. First and foremost, the amended Electricity Acts do not sufficiently address the issue of the 1 Stated as 100%, as the few individuals with incomes higher than US$ 2/day constitute a tiny total that adds up to a fraction of a decimal point (effectively, a rounding error). electrification of the poor (e.g. proposing new and innovative initiatives that would increase electrification of the poor). Secondly, the utilities, ministries of energy and regulatory agencies make no attempt to track electrification of the poor. Thirdly, the sequence of power sector reform measures appears to have been detrimental to electrification of the poor. In both countries, rural electrification was only addressed at the end of the reform process. Fourthly, reforms also appear to have failed to link rural electrification to the overall strategy of improving the performance of the electricity industry. Lastly, current rural electrification targets are very low and would, within the next decade, leave well over 80% of the rural population with no electrification even if the set targets are realized. The article concludes that although some of the reforms have had some benefical impacts on the region's electricity industry, the analysis presented demonstrates that they have not led to significant electrification of the poor. As a result, only a comprehensive transformation of ongoing power sector reforms could lead to greater electrification of the poor. The article ends with some suggestions on how reforms could be amended to ensure greater access to electricity among the poor in East Africa. The Electricity Act also appears not to provide for "ring-fencing" of the funds allocated for rural electrification. As witnessed in the Kenyan case, inadequate protection of the Rural Electrification Fund hobbles attempts to reach the poor.
doi:10.1016/s0973-0826(08)60510-4 fatcat:gwjl3lq4cbdqxivskdttdk4qey

Distribution and Contribution of K13-propeller Gene to Artemisinin Resistance in sub-Saharan Africa: A Systematic Review

Laura Nyawira Wangai, Kenny Kimani Kamau, Immaculate Marwa, Elly OMunde, Samuel Mburu, John Mwangi, Mark Webale, Dennis Butto, Lucy Kamau, John Hiuhu
2020 Biomedical Sciences  
The observed clinical failure after treatment with artemisinin combination therapy (ACT) has recently been confirmed in western Cambodia. Evidence of declining ACT efficacy has also been reported in Africa. Molecular markers for artemisinin resistance have played an essential role in monitoring the spread of the resistant phenotype and identifying the mechanisms of resistance. Several candidate genes, including the P. falciparum kelch propeller region (K13). However, in sub-Saharan Africa,
more » ... te the observed delayed clearance after treatment, the association between ART resistance and K13 gene is questionable as studies have not found significant mutations or an association with the delayed parasite clearance rate following ACT treatment. There is need for more data to clarify the significance of K13-propeller mutations as markers of artemisinin resistance in Africa. An electronic search of studies in sub-Saharan Africa from 2014 to date was done via PubMED, SCOPUS, and EMBASE databases. The search was conducted independently by two librarians. The articles were screened for selection using a priori criteria set following PRISMAP and STREGA guidelines. Data analysis was performed in R-statistics software. A total of 197 articles were identified from Pubmed= 139, Research gate=40, Bibliography/other searches=18, of which 102 did not meet the selection criteria. A total of 74 independent K13 mutations were identified across malaria-affected African countries. Only 7 unconfirmed K13 mutations were associated with delayed parasite clearance half-life (t1/2>3 h). The majority, 47.5% (35/74), of the mutations were reported in single P. falciparum parasite isolate. Of the 74 K13-mutations, nearly two-thirds were reported as new alleles. Twenty-seven (27) non-synonymous mutations in the Pfkelch13 gene were identified. Although artemisinin resistance in South-East Asia seems to be a heritable genetic trait, none of the candidate genes suggested by earlier studies confer artemisinin resistance to the observed clinical failure in Africa. Mutations outside the Pfkelch13 propeller region associated with increased ART parasite clearance half-life occur in malaria-affected regions in Africa. The use of a genome-wide approach by whole genome sequencing and gene expression transcriptome studies to identify the molecular basis of artemisinin resistance is warranted to aid in identification potential markers for ACT resistance in Africa.
doi:10.11648/ fatcat:dibd6umh7vhw3nwv46ffqp67di
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