A review of electroencephalograms done at the Kenyatta National Hospital, Nairobi

Background: Electroencephalogram based studies done elsewhere suggest that epileptiform activity originates predominantly from the left cortical hemisphere. There is evidence that partial epilepsies (focal spike and wave epileptiform discharges on tracings) connotes focal;secondary structural cortical dysfunction.Studies seeking similar findings have not been done locally. Objective: To review electroencephalograms (BEGs) done at Kenyatta National Hospital (KNH); looking for various types of epileptiform discharges and their cerebral cortex of origin. Design: Retrospective observational study. Setting: Kenyatta National Hospital, Nairobi, Kenya- from January 1986 to June 2004 Results: A total10431EEG records were reviewed. Ninety Eight percent of referrals for EEG evaluation was for clinical differential diagnosis of epilepsy. AbnormalBEGs comprised 32.2% of the study population. Epileptiform abnormalities (i.e.focal spike and wave,generalized spike and wave and 3Hz spike and wave) discharges accounted for75.2% of all abnormal EEG waveform discharges.Of the epileptiform abnormalities, focal spike and wave discharges comprised 71%. Focal spike and wave discharge implies a possible secondary aetiology of epilepsy.The left cerebral hemisphere was the origin of 49.8% of focal spike and wave epileptiform EEG discharges. Multifocal loci in cerebral cortices (i.e. frontal, temporal and parietal) were the foci of origin of abnormal EEG waveforms in 69.9% of recordings. Conclusion: Focal spike and wave epileptiform discharges, with attendant likely secondary aetiology of epilepsy is predominantly evident in this study. It contrasts findings from western literature.The left cerebral hemisphere is more epileptogenic as is noted in other studies

A unified rule-based small-signal modelling technique for two-switch, non-isolated DC-DC converters in CCM

DATA AVAILABILITY STATEMENT : All generated data is contained in the manuscript.The inherent non-linear behavior of switch-mode power supplies complicates the task of computing their linear models, which are essential for a model-oriented control design of DC–DC converters. In a model-oriented control design approach, the accuracy of the plant model directly influences the performance of the control system as the plant parameters tend to be linked to the controllers’ gains. Moreover, the extractions of linear dynamic models of high-order non-linear plants such as DC–DC converters are laborious and mathematically intractable. Therefore, in this paper, a generalized expression that represents either the audio-susceptibility or the control-to-output voltage transfer function for voltage-mode control is proposed. The proposed generalization reduces the task of computing the small-signal model of a given converter to simple calculations of coefficients of generalized transfer function/expression. It is shown that the coefficients of the generalized model can be deduced by inspection, directly from the circuit diagram, allowing the whole model to be computed by inspection. Additionally, the proposed modelling technique will be shown to have secondary use of verifying accuracy even when conventional modelling techniques such as state-space averaging or circuit averaging are used.The National Research Foundation (NRF).https://www.mdpi.com/journal/energiesam2023Electrical, Electronic and Computer Engineerin

Task Shifting in HIV Clinics, Western Kenya

Background: United states Agency for International development-Academic Model for Providing Accesses to Healthcare (USAID-AMPATH) cares for over 80,000 HIVinfected patients. Express care (EC) model addresses challenges of: clinically stable patient’s adherent to combined-antiretroviral-therapy with minimal need for clinician intervention and high risk patients newly initiated on cART with CD4 counts ≤100 cells/mm3 with frequent need for clinician intervention. Objective: To improve patient outcomes without increasing clinic resources. Design: A descriptive study of a clinician supervised shared nurse model. Setting: USAID-AMPATH clinics, Western Kenya. Results: Four thousand eight hundred and twenty four patients were seen during the pilot period, 90.4% were eligible for EC of whom 34.6% were enrolled. Nurses performed all traditional roles and attended to two thirds and three quarters of stable and high risk patient visits respectively. Clinicians attended to one third and one quarter of stable and high risk patient visits respectively and all visits ineligible for express care. Conclusion: The EC model is feasible. Task shifting allowed stable patients to receive visits with nurses, while clinicians had more time to concentrate on patients that were new as well as more acutely ill patients.East African Medical Journal Vol. 87 No. 7 July 201

Unified approach for synthesis and analysis of non-isolated DC-DC converters

Transformational techniques unifying synthesis of two-state DC-DC converters and analytical synthesis techniques allowing generation of all possible converters meeting a certain criteria already exist. The analysis of a family of converters derived from a single converter cell has also been uni ed. Current waveforms generated by the family of converters were shown to be related. However, a concept or basic building blocks that facilitate uni ed synthesis, analysis, prediction of current waveforms and assignment of switch states over a very wide range of DC-DC converters is still lacking. This study will propose three 3-terminal basic building blocks and one 3-terminal lter block. It will be shown that between them, they are suf cient for realizing all non-isolated DC-DC converters excluding those with coupled inductors. The various DC-DC converters fall into those realized through cascade, stacked, stacked plus cascade, interleaved/paralleled or differential connection of the basic building blocks. A systematic approach for evaluating input-output current gains will be presented. Moreover, a basic building block will be shown to have xed switching states for proper operation. This gives rise to the generation of a unique set of current waveforms at the three terminals irrespective of where a basic building block is embedded. It has been shown that the effort and time needed to design DC-DC converters can be reduced as switching device stresses can be estimated without the need for tedious rst principle derivations.http://ieeexplore.ieee.org/xpl/RecentIssue.jsp?punumber=6287639am2022Electrical, Electronic and Computer Engineerin

A system dynamics-based scenario analysis of residential solid waste management in Kisumu, Kenya

The problem of solid waste management presents an issue of increasing importance in many low-income settings, including the progressively urbanised context of Kenya. Kisumu County is one such setting with an estimated 500 t of waste generated per day and with less than half of it regularly collected. The open burning and natural decay of solid waste is an important source of greenhouse gas (GHG) emissions and atmospheric pollutants with adverse health consequences. In this paper, we use system dynamics modelling to investigate the expected impact on GHG and PM_{2.5} emissions of (i) a waste-to-biogas initiative and (ii) a regulatory ban on the open burning of waste in landfill. We use life tables to estimate the impact on mortality of the reduction in PM_{2.5} exposure. Our results indicate that combining these two interventions can generate over 1.1 million tonnes of cumulative savings in GHG emissions by 2035, of which the largest contribution (42%) results from the biogas produced replacing unclean fuels in household cooking. Combining the two interventions is expected to reduce PM_{2.5} emissions from the waste and residential sectors by over 30% compared to our baseline scenario by 2035, resulting in at least around 1150 cumulative life years saved over 2021–2035. The contribution and novelty of this study lies in the quantification of a potential waste-to-biogas scenario and its environmental and health impact in Kisumu for the first time