Public secondary school libraries in Nairobi and the satisfaction of the curriculum needs among history teachers.

Thesis (M.I.S.)-University of Natal, Pietermaritzburg, 1999.The aim of this study is to investigate the level of awareness of history teachers in public secondary schools in Nairobi, Kenya, of the benefits of library use for the curriculum. The availability of school libraries in public secondary schools in Nairobi provided a context for this investigation into teacher library use. In order to establish if libraries are used effectively, or used at all, for curriculum purposes, literature on this was searched and little came from Nairobi or even Kenya. This lack of information in this area formed a justification for investigation because libraries exist in many public schools in Nairobi and they have the potential to have a positive influence. A survey of literature internationally illustrates the degree of the serious attention both history as a discipline, and library and the curriculum receive. History is given attention because of its role in both maintaining and revolutionising order in a country. In the case of resource-based learning, many countries have shifted to a child-centred approach. This requires much more use of libraries than traditional teaching methods. The evaluation of teacher and librarian views was undertaken by means of a survey. In the survey questionnaires were used. The population was that provided by the Director of Education in Nairobi and a corresponding list of schools where teachers and librarians were employed is given. The findings of the survey established the level of awareness of history teachers to resource based education that took account of library-curriculum partnership. The study established the need for greater attention towards school libraries in the allocation of budgets, building resources that are needed, and management. Staff development of both teachers and librarians was suggested in order to promote resource-based education. To achieve this, a written policy on the management of school libraries is suggested

Intelligent Model Based Imbalance Fault Detection and Identification System of a Turbocharger Based on Vibration Analysis

Inappropriate fault detection of turbocharger’s operating parameters has generated unnecessary economic loss due to unplanned down-time. This results to a combination of late and inaccurate diagnosis of the turbocharger faults by the employed maintenance systems. This study, used a Model-based fault diagnosis approach to identify imbalance fault in a turbocharger rotor system. In this approach, the generalized theoretical equation of motion for both healthy and faulty system models of a complete turbocharger rotor, were developed using the Finite element method. A test rig for the turbocharger rotor with sensors to monitor its dynamic behavior under the influence of the aforementioned faulty condition was also developed. Following Modal Expansion, curve fitting technique was used to minimize the error between a set of equivalent experimental and numerical results. From the results, the theoretical Frequency response functions developed from Finite Element Method fault models had good agreement with the Time and frequency-based responses measured from experimental data for the induced imbalance fault condition, hence, validating the theoretical fault models developed in this study. Using Modal Expansion technique, data from nodal residual forces generated from the developed numerical fault model was compared with measured corresponding experimental nodal residual forces data. The results showed good agreement between the theoretical and experimental findings. Hence, the Model based fault identification scheme implemented in this study successfully identified the magnitude, severity and exact location of imbalance faulty conditions. Keywords: Model based, fault detection and identification, Turbocharger, vibration, Modal expansion, Test rig, Imbalance, modelling. DOI: 10.7176/ISDE/12-2-06 Publication date: August 30th 202

Optimal placement of a piezoelectric ring in an ultrasonic powder transport system

The transport of powder materials is an important aspect of process engineering. Various industries such as the food, chemical, pharmaceutical, coating, information and telecommunication industries have set a high demand on the performances of existing plants, which are mainly for bulk powder transfer. Modern systems demand powder transport systems which have a high quantitative accuracy. Therefore, the ultrasonic material transport process technology has in the last few years developed into an attractive alternative compared to the classical technologies. This technology involves transfer of powder through a pipe in which the ultrasonic waves are transmitted. However, this technology is not refined. In this paper, the optimal placement of the piezoelectric transducer on the pipe in order to produce traveling ultrasonic waves is investigated. A given length of the pipe is considered for transmission of the ultrasonic waves

Determination of resonant frequency of a piezoelectric ring for generation of ultrasonic waves

Ultrasound technology has become an important aspect in material handling and machining. Standing and traveling ultrasonic waves have been applied in powder transportation, feeding, dosing and supply of small amounts of powder with high quantitative accuracy and precision. Piezoelectric actuators are the most commonly used to generate the ultrasonic waves in various devices. Hence, these devices have presented a unique, economic and simple means of accurate handling of powder. This paper describes the determination of the resonant frequency of a piezoelectric ring that can be applied for generation of the ultrasonic waves. The resonant frequency is important in determining the highest amplitude of the vibration of the ring

Mutations in the “a” Determinant Region of Hepatitis B Virus Genotype A among Voluntary Kenyan Blood Donors

Background: Occurrence of mutations within the major antigenic alpha determinant region of hepatitis B surface antigen (HBsAg can alter HBV antigenicity resulting in   failures in diagnosis, vaccine and hepatitis B immunoglobulin therapy. Objective: This study aimed at detection of mutations in the “a” determinant region of HBV surface antigen among voluntary blood donors in Kenya. Design: A cross sectional study involving serology and molecular techniques Settings: This study involved analysis of samples from blood transfusion centers Subjects: A total of 301 blood samples from donor blood were collected for the study. Methods: Sero-status for HBsAg was determined using Enzyme-Linked Immunosorbent Assay (ELISA). A fragment of the S gene including the "a" determinant was amplified by PCR from the HBsAg positive samples and sequenced for mutation analysis. Mutations and phylogenetic analyses were performed using Mega 6 software, Bioedit software and GENETYX® software version 9.1.0. Results: Out of the 301 samples tested 69/301 (22.9%) were Polymerase Chain Reaction (PCR) positive including 2/69(2.9%) were sero-negative for HBsAg. All isolates were genotype A, sub-genotype A1. A total of 29 mutations were observed of which 37.9% were located within the “a” determinant. Mutations T143M and K122R were the most frequent in this study. Escape mutations associated with diagnostic failure, vaccine and immunoglobulin therapy escape were also identified. Conclusions: These findings are important for policies related to vaccine implementation and therapeutic and diagnostic guidelines. Keywords: Escape mutants, genotype, hepatitis B virus, antigenic determinant, surface antigen

Interaction Between Climatic, Environmental, and Demographic Factors on Cholera Outbreaks in Kenya

Background: Cholera remains an important public health concern in developing countries including Kenya where 11,769 cases and 274 deaths were reported in 2009 according to the World Health Organization (WHO). This ecological study investigates the impact of various climatic, environmental, and demographic variables on the spatial distribution of cholera cases in Kenya. Methods: District-level data was gathered from Kenya’s Division of Disease Surveillance and Response, the Meteorological Department, and the National Bureau of Statistics. The data included the entire population of Kenya from 1999 to 2009. Results: Multivariate analyses showed that districts had an increased risk of cholera outbreaks when a greater proportion of the population lived more than five kilometers from a health facility (RR: 1.025 per 1% increase; 95% CI: 1.010, 1.039), bordered a body of water (RR: 5.5; 95% CI: 2.472, 12.404), experienced increased rainfall from October to December (RR: 1.003 per 1 mm increase; 95% CI: 1.001, 1.005), and experienced decreased rainfall from April to June (RR: 0.996 per 1 mm increase; 95% CI: 0.992, 0.999). There was no detectable association between cholera and population density, poverty, availability of piped water, waste disposal methods, rainfall from January to March, or rainfall from July to September. Conclusion: Bordering a large body of water, lack of health facilities nearby, and changes in rainfall were significantly associated with an increased risk of cholera in Kenya

Mutations in the “a” Determinant Region of Hepatitis B Virus Genotype A among Voluntary Kenyan Blood Donors

Occurrence of mutations within the major antigenic alpha determinant region of hepatitis B surface antigen (HBsAg can alter HBV antigenicity resulting in   failures in diagnosis, vaccine and hepatitis B immunoglobulin therapy. This study aimed at detection of mutations in the “a” determinant region of HBV surface antigen among voluntary blood donors in Kenya. This was a cross sectional study involving serology and molecular techniques. This study involved analysis of samples from blood transfusion centers. A total of 301 blood samples from donor blood were collected for the study.  Sero-status for HBsAg was determined using Enzyme-Linked Immunosorbent Assay (ELISA). A fragment of the S gene including the "a" determinant was amplified by PCR from the HBsAg positive samples and sequenced for mutation analysis. Mutations and phylogenetic analyses were performed using Mega 6 software, Bioedit software and GENETYX® software version 9.1.0. Out of the 301 samples tested 69/301 (22.9%) were Polymerase Chain Reaction (PCR) positive including 2/69(2.9%) were sero-negative for HBsAg. All isolates were genotype A, sub-genotype A1. A total of 29 mutations were observed of which 37.9% were located within the “a” determinant. Mutations T143M and K122R were the most frequent in this study. Escape mutations associated with diagnostic failure, vaccine and immunoglobulin therapy escape were also identified. These findings are important for policies related to vaccine implementation and therapeutic and diagnostic guidelines. Keywords: Escape mutants, genotype, hepatitis B virus, antigenic determinant, surface antige

Development of immunoassays for detection of Human Immunodeficiency Virus based on Consensus env gp41 Immunodominant Region Peptide from HIV-1 infections in Kenya

Background: Human Immunodeficiency Virus (HIV) is characterized by high rates of genetic variability in vivo that could affect the performance of the HIV antibody-based detection kits. Objective: This study aimed at developing immunoassays for HIV based on Consensus env gp41 Immunodominant region (IDR) from HIV infections in Kenya. Methods: HIV RNA was extracted from 91 samples collected from 5 regional blood transfusion centers in Kenya. The RNA was reverse transcribed, sequenced in the env gp41-Immunodominant Region (IDR) and the Consensus sequence generated used to synthesize corresponding peptide. The Global HIV envgp41-IDR Consensus peptide was obtained from the literature and also synthesized. The two peptides were used to separately develop HIV immunoassays based on Enzyme-linked Immunosorbent Assay (ELISA) and Lateral Flow Assay (LFA) platforms and the performance of developed assays was evaluated. The same HIV env gp41 IDR peptides were used to develop ELISA-based immunoassays for determination HIV Incidence / Recency. Results: The study did not find significant difference between the performance of the immunoassays that were developed with Consensus env gp41-IDR peptide (Kenya) and those developed using Consensus env gp41-IDR peptide (Global). However, the study found a significant difference between the performance of HIV ELISA for HIV Incidence testing that was developed with Consensus envgp41-IDR peptide (Kenya) and that which was developed using Consensus envgp41-IDR peptide (Global) with the former displaying superior performance. Conclusions: The developed immunoassays demonstrated that both Consensus env gp41-IDR peptides (Kenya and Global) could be used to develop HIV immunoassays but Consensus env gp41-IDR peptide (Kenya) could be more suitable for development of HIV Incidence assays in Kenya. Keywords: HIV, Consensus sequence, env gp41-Immunodominant Region, Immunoassay

Performance of selected HIV testing centers in a HIV Proficiency Testing Scheme in Kenya: a case study

Background: The Proficiency Testing (PT) for Human Immunodeficiency Virus (HIV) using Lateral flow assays provides an avenue for participating institutions/individuals to assess their technical competence in testing for HIV using LFAs that are recommended in the National HIV Testing Algorithm (NHTA) in Kenya. It also provides confidence to the participating institutions and potential users of their services besides giving the institutions an opportunity for improvement. Objective: To determine the performance of selected HIV testing centers in a HIV PT Scheme in Kenya Methods: Fifty one participants (51) in Kenya were selected from 7 sites (Kisumu, Mombasa, Kilifi, Nairobi and Malindi) to participate in this PT round. The sites comprised both private sector and institutions that do not participate in the National HIV referral Lab-PT scheme. They were provided with panels containing six samples to analyze using the current NHTA in Kenya. Obtained results were sent to our laboratory electronically. Results: Eighty nine percent (89.0%) of the panels were correctly identified by the participants as positive or negative. Of the 11.0% errors, 74.2% were committed in one or more test result obtained while 12.9% committed in failure to follow NHTA. Two minor errors repeated by participants were; failure to record the final results in spite of obtaining correct tests and correct reactive results with the first and second test kits but in conclusion the participant recorded negative (12.9%). Root cause analysis revealed that the error committed by participants were as a result of failure to observe the kit manufactures’ instructions and NHTA guidelines. Conclusion: The results of this PT Scheme enhance the need for constant training of personnel conducting HIV testing and Counseling in Kenya on proper techniques of carrying out HIV testing using Lateral flow assays in the NHTA. Key words: HIV, Proficiency Testing, errors, false negative, false positive

The Potential for DPPIV/CD26 usage as a surrogate marker for Antiretroviral Therapy Efficacy in HIV Infected populations

Background: Human Immunodeficiency Virus (HIV) viral load and CD4+ cell counts are the most commonly used markers for monitoring efficacy of anti-retroviral therapy (ART) in HIV infected individuals. The high cost of viral load monitoring limits its usage in resource limited countries, often leaving the use of CD4+ T cell counts as the only alternative. Though cheaper and more readily available, CD4+ cell counts as a measure of detecting treatment failure, is an unreliable predictor of disease progression. Hence, there is a need for more sensitive alternative, but less costly techniques for detecting treatment failure which can be used in resource limited settings. Objective: To evaluate the feasibility of using plasma CD26/Dipeptidyl peptidase IV (DPPIV) as a novel marker for clinical evaluation of treatment efficacy in HIV infected children. Method: Blood samples collected from HIV+ children (n=76) before and after initiation on ART, were assessed for HIV RNA (viral load), CD4+ T-cell count and DPPIV/CD26 levels. Viral load levels were analyzed using Roche Amplicor HIV-1 Monitor Test kit; CD4+ T-Cell Counts were analyzed using BD FACS Calibur flow cytometer while DPPIV/CD 26 levels were analyzed using Human DPPIV/CD26 Quantikine ELISA kit (R&D Systems, Minneapolis MN). Results: The plasma DPPIV/CD26 levels increased significantly in children after ART initiation (p = 0.017), while the viral load levels declined after ART initiation with subsequent CD4+ cell counts increase. The DPPIV/CD 26 increase positively correlated with viral load decrease while negatively correlating to the CD4+ cell count increase. Conclusion: These findings demonstrate an inverse relationship between DPPIV/CD26 levels and HIV viral load and the direct proportionality of CD4+ Cell counts and DPPIV/CD26 levels, suggesting potential for use of DPPIV/CD26 as a surrogate marker for evaluating HIV disease progression in children receiving anti-retroviral therapy. Key words: CD26/Dipeptidyl peptidase IV (DPPIV), ELISA, Surrogate marker, Viral Load, CD4 Count, antiretroviral