Gum Arabic as an Admixture in Modified Concrete Mixed with Calcined Kaolin

The use of calcined kaolin (CK) as a cementitious material in construction has attracted the interest of various researchers due to its environmental, mechanical, and physical qualities, all of which contribute to the lowering of cement usage. Studies have reported numerous problems associated with its use in concrete, apart from the ecological benefit that CK can provide. For instance, there is an issue of increased water demand due to smaller particle size, which generates much more heat in concrete, which has a detrimental effect on the mechanical and physical properties of concrete. This paper presents the analysis of an investigation aimed at using gum Arabic (GA) as a biopolymer admixture and calcined kaolin as a partial replacement of cement to improve the mechanical properties and durability of concrete. GA proportions ranged from 0 to 1% by weight of cement. Calcined kaolin (CK) was used to replace 5, 10, 15, 20, 25, and 30% of the cement content, respectively. Compressive strength, splitting tensile strength, density, strength loss, and weight loss tests were all performed to validate the structural performance of the modified concrete. The compressive tests, performed after 28 days from the time the mixture was made, demonstrated that the maximum percentage of CK that could replace cement without affecting the mechanical properties of concrete was 20%. Beyond 20%, concrete does not exhibit good compressive strength properties. The results also revealed decreased compressive strength and splitting tensile strength tests as the percentage of CK increased. After 56 days, compressive strength at 5% CK and 10% CK increased slightly by 0.743% and 1.162 %, respectively, compared to the control sample. The inclusion of 0.8%GA increased the compressive strength by 8.94% compared to the control sample (0%CK + 0%GA + 100%OPC) after 56 days. The results of durability tests showed that 0.6% GA had a higher compressive strength than other percentages containing GA. Doi: 10.28991/CEJ-2022-08-05-010 Full Text: PD

Relationship Between Teachers’ Motivation Teaching HIV/ADS Education And Students’ Knowledge And Attitude Towards Sexual Behaviour In Secondary Schools In Coast Region, Kenya

Education plays an important role in curbing the spread of HIV and AIDS among the youth. However, there is little known how teachers’ motivation in teaching HIV/AIDS education affects students’ knowledge and attitudes towards sexual behaviour. The purpose of the study was to determine the relationship between teachers’ level of motivation in teaching HIV/AIDS education and students’ knowledge and attitude towards sexual behaviour in secondary schools in the Coast Region of Kenya. The study used descriptive survey research design. Proportional, purposive and random sampling methods were used to choose the participants. The samples comprised 421 respondents of which 33 were teachers and 388 students in 13 secondary schools. Questionnaires, document analysis and interview schedule were used to collect the data. Reliability coefficients of the instruments were 0.8 for both teachers and students. Both descriptive and inferential statistics were used in data analysis. The descriptive statistics that were used were frequencies and percentage. Chi-squire statistics was used to test the hypothesis in the study. The hypothesis testing was done at α = 0.05 level of significance. The data collected in this study was analysed using Statistical Package for Social Sciences (SPSS) computer programme version 20.0. The findings showed that there is a relationship between teachers’ level of motivation in teaching of HIV/AIDS education and students’ knowledge and attitudes towards sexual behaviour. It further revealed that majority of Form 4 students had negative attitude towards sexual behaviour. The study recommends that the Teachers Service Commission and other stakeholders should motivate teachers who teach HIV/AIDS education in secondary schools. Key words: teachers’ motivation, students’ knowledge, students’ sexual behaviou

Effect of Corporate Governance on Performance of Savings and Credit Co-operative Societies in Kakamega County

The study on the effect of corporate governance on performance of SACCOs was based on the revelations that some cooperatives are ailing, while others are very vibrant and sustainable. Good corporate governance is now accepted as vital to achieving the Millennium Development Goals and as a pre-condition for sustainable economic growth. The purpose of this study was to examine the effect of corporate governance on performance of SACCOs. Corporate governance was operationalized by transparency and accountability, shareholder involvement, policies and guidelines, and rewards and incentives while performance of SACCOs was characterized by growth in share capital/deposits, growth in membership, growth in turnover, and customer satisfaction. The significance of the study was to demonstrate the need for good corporate governance in the co-operative movement. Extensive literature was reviewed to establish the importance of the study, highlighted knowledge gaps and provided benchmark for comparison of the findings. The target population was 33 Savings and Credit Co-operative Societies in Kakamega County. Stratified sampling was applied to get the number of respondents in the study. The respondents were the executive board members, ordinary members, and Chief Executive Officers from the sampled SACCOs. Descriptive and correlational survey designs were both used. Data collection was conducted by use of a questionnaire and document review. Cronbach’s alpha coefficient (KR 20), a test of reliability was computed to define the correlation of items contained in the instruments. Piloting of the instruments was through pre-testing of the instruments by carrying out a pilot study in two co-operatives that is Weko and Wesacco. Data was analyzed using descriptive and inferential statistics. The study found that corporate governance had a significant positive effect on performance of SACCOs. Recommendations from this study included the need for all SACCOs to embrace corporate governance since it enhances performance. Measures should also be put in place for SACCOs to embrace right culture, learning, and right organizational structures as they implement their plans. However, the study has recommended further researches on the effect of corporate governance in other types of co-operatives like housing, marketing, and co-operative unions and research that will cover a wider area. Key words: Corporate Governance, Performance, Savings and Credit Co-operatives, Keny

In vitro anthelmintic activity of Albizia gummifera, Crotalaria axillaris, Manilkara discolor, Teclea trichocarpa and Zanthoxylum usambarense using sheep nematodes

Background: Albizia gummifera, Crotalaria axillaris, Manilkara discolor, Teclea trichocarpa and Zanthoxylum usambarense are used to treat different ailments in many parts of the world. For instance, A. gummifera is used to treat stomach pains, malaria, diarrhoea and sleeping sickness while C. axillaris treats ophthalmic disorders and kidney problems. Manilkara discolor stem bark infusion is used to treat stomach disorders and as an astringent while T. trichocarpa has been used to treat malaria, helminth infections and fever. Zanthoxylum usambarense is used to treat rheumatism, backache, painful joints, fever, sore throat, tonsillitis, chest pains, malaria, abscesses and wounds. Objective: The aim was to determine whether the crude plant extracts have in vitro anthelmintic activity. Materials and methods: Different parts of the plants were acquired from Ngong Hills forest, Kajiado County, Kenya in May 2012, dried and macerated to exhaustion with dichloromethane: methanol (1:1, v/v) solution. Nematode eggs (Haemonchus Spp, Trichostrongylus Spp and Oesophagostomum Spp) were obtained from infected sheep rectums at Department of Vet Farm, University of Nairobi based at Kabete. Varying concentrations of water solutions of the dry crude extracts were prepared. Egg hatch (EHA) and larvae development assays (LDA) were used to test the extracts’ effects on nematode egg hatching and larvae development, respectively Results: Albizia gummifera (root bark) and Zanthoxylum usambarense (stem bark) showed high activity (IC50 below 300 μg / mL) in both tests.  Albizia gummifera (root, stem bark and pods), Zanthoxylum usambarense root bark, Crotalaria axillaris twigs and Teclea trichocarpa root and stem bark showed high activity in LDAbut moderate activity (300 μg / mL < IC50 < 500 μg / mL)  in EHA. Teclea trichocarpa twigs showed moderate activity in LDA but low (IC50 > 500 μg / mL) activity in EHA. Manilkara discolor extracts showed low activity in both tests. Conclusion: Different extracts of the plants tested may inhibit nematode growth and development and hence warrant in vivo tests would support their ethnomedicinal application. Key words: Anthelmintic activity, egg hatch, larval development, Haemonchus, Trichostrongylus, Oesophagostomu

Factors leading to disparity in lung cancer diagnosis among black/African American communities in the USA: a qualitative study

This is the final version. Available on open access from BMJ Publishing Group via the DOI in this recordData availability statement: Data are available upon reasonable request. The authors confirm that the data supporting the findings of this study are available within the article and its supplementary materials. The data will become available immediately after publication, with no end date for anyone who wishes access.OBJECTIVE: This study has two objectives: first, to explore the diagnostic experiences of black/African American (BAA) patients with lung cancer to pinpoint pitfalls, suboptimal experiences and instances of discrimination leading to disparities in outcomes compared with patients of other ethnic backgrounds, especially white patients. The second objective is to identify the underlying causes contributing to health disparities in the diagnosis of lung cancer among BAA patients. METHODS: We employed a phenomenological research approach, guiding in-depth interviews with patients self-identifying as BAA diagnosed with lung cancer, as well as caregivers, healthcare professionals and community advocates knowledgeable about BAA experiences with lung cancer. We performed thematic analysis to identify experiences at patient, primary care and specialist levels. Contributing factors were identified using the National Institute of Minority Health and Health Disparities (NIMHD) health disparity model. RESULTS: From March to November 2021, we conducted individual interviews with 19 participants, including 9 patients/caregivers and 10 providers/advocates. Participants reported recurring and increased pain before seeking treatment, treatment for non-cancer illnesses, delays in diagnostic tests and referrals, poor communication and bias when dealing with specialists and primary care providers. Factors contributing to suboptimal experiences included reluctance by insurers to cover costs, provider unwillingness to conduct comprehensive testing, provider bias in recommending treatment, high healthcare costs, and lack of healthcare facilities and qualified staff to provide necessary support. However, some participants reported positive experiences due to their insurance, availability of services and having an empowered support structure. CONCLUSIONS: BAA patients and caregivers encountered suboptimal experiences during their care. The NIMHD model is a useful framework to organise factors contributing to these experiences that may be leading to health disparities. Additional research is needed to fully capture the extent of these experiences and identify ways to improve BAA patient experiences in the lung cancer diagnosis pathway.Cancer Research UKLUNGevity Foundatio

Evidence for Quantum Interference in SAMs of Arylethynylene Thiolates in Tunneling Junctions with Eutectic Ga-In (EGaIn) Top-Contacts

This paper compares the current density (J) versus applied bias (V) of self-assembled monolayers (SAMs) of three different ethynylthiophenol-functionalized anthracene derivatives of approximately the same thickness with linear-conjugation (AC), cross-conjugation (AQ), and broken-conjugation (AH) using liquid eutectic Ga-In (EGaIn) supporting a native skin (~1 nm thick) of Ga2O3 as a nondamaging, conformal top-contact. This skin imparts non-Newtonian rheological properties that distinguish EGaIn from other top-contacts; however, it may also have limited the maximum values of J observed for AC. The measured values of J for AH and AQ are not significantly different (J ≈ 10-1 A/cm2 at V = 0.4 V). For AC, however, J is 1 (using log averages) or 2 (using Gaussian fits) orders of magnitude higher than for AH and AQ. These values are in good qualitative agreement with gDFTB calculations on single AC, AQ, and AH molecules chemisorbed between Au contacts that predict currents, I, that are 2 orders of magnitude higher for AC than for AH at 0 < |V| < 0.4 V. The calculations predict a higher value of I for AQ than for AH; however, the magnitude is highly dependent on the position of the Fermi energy, which cannot be calculated precisely. In this sense, the theoretical predictions and experimental conclusions agree that linearly conjugated AC is significantly more conductive than either cross-conjugated AQ or broken conjugate AH and that AQ and AH cannot necessarily be easily differentiated from each other. These observations are ascribed to quantum interference effects. The agreement between the theoretical predictions on single molecules and the measurements on SAMs suggest that molecule-molecule interactions do not play a significant role in the transport properties of AC, AQ, and AH.

Conductance statistics from a large array of sub-10 nm molecular junctions

Devices made of few molecules constitute the miniaturization limit that both inorganic and organic-based electronics aspire to reach. However, integration of millions of molecular junctions with less than 100 molecules each has been a long technological challenge requiring well controlled nanometric electrodes. Here we report molecular junctions fabricated on a large array of sub-10 nm single crystal Au nanodots electrodes, a new approach that allows us to measure the conductance of up to a million of junctions in a single conducting Atomic Force Microscope (C-AFM) image. We observe two peaks of conductance for alkylthiol molecules. Tunneling decay constant (beta) for alkanethiols, is in the same range as previous studies. Energy position of molecular orbitals, obtained by transient voltage spectroscopy, varies from peak to peak, in correlation with conductance values.Comment: ACS Nano (in press

Diarrhoea Complicating Severe Acute Malnutrition in Kenyan Children: A Prospective Descriptive Study of Risk Factors and Outcome

BACKGROUND: Severe acute malnutrition (SAM) accounts for two million deaths worldwide annually. In those hospitalised with SAM, concomitant infections and diarrhoea are frequent complications resulting in adverse outcome. We examined the clinical and laboratory features on admission and outcome of children with SAM and diarrhoea at a Kenyan district hospital. METHODS: A 4-year prospective descriptive study involving 1,206 children aged 6 months to 12 years, hospitalized with SAM and managed in accordance with WHO guidelines. Data on clinical features, haematological, biochemical and microbiological findings for children with diarrhoea (≥ 3 watery stools/day) were systematically collected and analyzed to identify risk factors associated with poor outcome. RESULTS: At admission 592 children (49%) had diarrhoea of which 122 (21%) died compared to 72/614 (12%) deaths in those without diarrhoea at admission (Χ(2) = 17.6 p&lt;0.001). A further 187 (16%) children developed diarrhoea after 48 hours of admission and 33 died (18%). Any diarrhoea during admission resulted in a significantly higher mortality 161/852 (19%) than those uncomplicated by diarrhoea 33/351 (9%) (Χ(2) = 16.6 p&lt;0.001). Features associated with a fatal outcome in children presenting with diarrhoea included bacteraemia, hyponatraemia, low mid-upper arm circumference &lt;10 cm, hypoxia, hypokalaemia and oedema. Bacteraemia had the highest risk of death (adjusted OR 6.1; 95% C.I 2.3, 16.3 p&lt;0.001); and complicated 24 (20%) of fatalities. Positive HIV antibody status was more frequent in cases with diarrhoea at admission (23%) than those without (15%, Χ(2) = 12.0 p = 0.001) but did not increase the risk of death in diarrhoea cases. CONCLUSION: Children with SAM complicated by diarrhoea had a higher risk of death than those who did not have diarrhoea during their hospital stay. Further operational and clinical research is needed to reduce mortality in children with SAM in the given setting

The Electrical Resistance of AgTS-S(CH2)n-1CH3//Ga2O3/EGaIn Tunneling Junctions

Tunneling junctions having the structure AgTS–S(CH2)n−1CH3//Ga2O3/EGaIn allow physical–organic studies of charge transport across self-assembled monolayers (SAMs). In ambient conditions, the surface of the liquid metal electrode (EGaIn, 75.5 wt % Ga, 24.5 wt % In, mp 15.7 °C) oxidizes and adsorbs―like other high-energy surfaces―adventitious contaminants. The interface between the EGaIn and the SAM thus includes a film of metal oxide, and probably also organic material adsorbed on this film; this interface will influence the properties and operation of the junctions. A combination of structural, chemical, and electrical characterizations leads to four conclusions about AgTS–S(CH2)n−1CH3//Ga2O3/EGaIn junctions. (i) The oxide is ∼0.7 nm thick on average, is composed mostly of Ga2O3, and appears to be self-limiting in its growth. (ii) The structure and composition (but not necessarily the contact area) of the junctions are conserved from junction to junction. (iii) The transport of charge through the junctions is dominated by the alkanethiolate SAM and not by the oxide or by the contaminants. (iv) The interface between the oxide and the eutectic alloy is rough at the micrometer scale.Chemistry and Chemical Biolog