ghanaopendata/ghanaian-research-english huggingface dataset:
Hexarelin protects cardiac H9C2 cells from angiotensin II-induced hypertrophy via the regulation of autophagy

Hexarelin is a synthetic growth hormone-releasing peptide that exerts cardioprotective effects. Regulation of autophagy is known to be cardioprotective so this study examined the role of autophagy and potential regulatory mechanisms in hexarelin-elicited anti-cardiac hypertrophic action in cardiomyocytes subjected to hypertrophy. H9C2 cardiomyocytes were subjected to hypertrophy by angiotensin-II (Ang-II). Autophagic light chain-3 (LC3) and cytoskeletal proteins were determined by immunofluorescence assay. Autophagy was also detected using monodansylcadaverine (MDC) for autophagic vacuole visualization and Cyto-ID staining for autophagic flux measurement. Molecular changes were analysed by Western blotting and qRT-PCR. Apoptosis was evaluated using flow cytometry and TUNEL assay. ATP content and CCK-8 assay were used in assessing enhanced cell survival whilst oxidative stress was analysed by measuring malondialdehyde(MDA) and superoxide dismutase(SOD) levels. Ang-II induced cardiomyocyte hypertrophy, oxidative stress, apoptosis and decreased cell survival, all of which were significantly suppressed by hexarelin treatment which also enhanced autophagy in hypertrophic H9C2 cells. Furthermore, inhibition of hexarelin induced autophagy by 3-methyladenine (3MA) abolished the anti-hypertrophic function of hexarelin and also abrogated the protection of hexarelin against cell survival inhibition and apoptosis. Conversely, the application of autophagy stimulator rapamycin in H9C2 hypertrophic cells inhibited apoptosis, cell survival and reduced cell size as well. Additionally, hexarelin regulated the upstream signalling of autophagy by inhibiting the phosphorylation of mammalian target of rapamycin(mTOR). We propose that hexarelin plays a novel role of attenuating cardiomyocyte hypertrophy and apoptosis via an autophagy-dependent mechanism associated with the suppression of the mTOR signalling pathway.

Source: UCC
Hierarchical Linear Modeling of the relationship between Attitudinal and Instructional Variables and Mathematics Achievement

Students’ achievement in mathematics is often considered necessary for the success of the future of a country. Therefore, the training and preparation of students to do well in mathematics has become fundamental goal of education for most countries and more specifically in Ghana. Applying Hierarchical Linear Modeling on the Trends in International Mathematics and Science Study (TIMSS) 2007 data, the relationship between attitudinal and instructional variables and mathematics achievement among Ghana’s grade eight students was examined. Prior to the analyses, exploratory factor analyses were conducted for clusters of similar items to reduce the number of predictor variables. The results indicate that student’s gender, educational aspirations, self-confidence in mathematics, value for mathematics, and frequent use of some instructional variables were significant positive predictors at Level 1. Whiles amount of homework, years of teaching, major area of study were significant positive predictors, teaching license or certificate was a significant negative predictor at Level 2.

Source: UCC
High electron thermal conductivity of chiral carbon nanotubes

Solving the Boltzmann kinetic equation with energy dispersion relation obtained in the tight binding approximation, the carrier thermal conductivity Ke of a chiral carbon nanotube (CCNT) was determined. The dependence of Ke on temperature T, chiral geometric angle fa and overlap integrals Az and As were obtained. The results were numerically analysed. Unusually high values of Ke were observed suggesting that ne is nontrivial in the calculation of the thermal conductivity K of CCNT. More interestingly we noted also that at 104 K and for A2 and As values of 0.020 eV and 0.0150 eV respectively the ne value is about 41000 W/mK as reported for a 99.9% pure 12 C crystal. We predict that the electron thermal conductivity of CCNT should exceed 200,000 W/mK at ~ 80 K

Source: UCC
High frequency conductivity in carbon nanotubes

We report on theoretical analysis of high frequency conductivity in carbon nanotubes. Using the kinetic equation with constant relaxation time, an analytical expression for the complex conductivity is obtained. The real part of the complex conductivity is initially negative at zero frequency and become more negative with increasing frequency, until it reaches a resonance minimum at ω ∼ ωB for metallic zigzag CNs and ω<ωB for armchair CNs. This resonance enhancement is indicative for terahertz gain without the formation of current instabilities induced by negative dc conductivity. We noted that due to the high density of states of conduction electrons in metallic zigzag carbon nanotubes and the specific dispersion law inherent in hexagonal crystalline structure result in a uniquely high frequency conductivity than the corresponding values for metallic armchair carbon nanotubes. We suggest that this phenomenon can be used to suppress current instabilities that are normally associated with a negative dc differential conductivity

Source: UCC
High frequency conductivity of hot electrons in carbon nanotubes

High frequency conductivity of hot electrons in undoped single walled achiral carbon nanotubes (CNTs) under the influence of ac-dc driven fields is considered. We investigated semi classically by solving the Boltzmann’s transport equation with and without the presence of the hot electrons source to derive the current densities. Plots of the normalized current density versus frequency of ac-field reveal an increase in both the minimum and maximum peaks of normalized current density at lower frequencies as a result of a strong enough injection of hot electrons. The applied ac-field plays twofold role of suppressing the space-charge instability in CNT and simultaneously pumping energy for lower frequency generation and amplification of THz radiations which have enormous promising applications in very different areas of science and technology

Source: UCC
High Incidence of Moderately Reduced Renal Function and Lead Bioaccumulation in Agricultural Workers in Assin South District, Ghana: A Community-Based Case-Control Study

Background. The quest to enhance agricultural productivity and crop yields has led to increased use of agrochemicals on a global scale. Long-term use of these agrochemicals may be associated with adverse health implications. Objective. To assess haema- tological indices, renal function, heavy metal bioaccumulation in farmers and sprayers, and their use of personal protective equipment (PPE). Materials and Methods. This community-based case-control study was conducted from January 2018 to June 2018 in the Assin South District, Central Region, Ghana. A total of 144 participants were conveniently sampled: 83 agricultural workers (cases) and 61 indigenes with no direct exposure to agrochemicals (controls). Structured questionnaire was used to obtain demographic data as well as agricultural work practices followed by cases. Venous blood samples were drawn from participants and used for estimating full blood count and renal function (serum creatinine (CRE), blood-urea nitrogen (BUN), BUN : CRE ratio, and estimated GFR (eGFR)). Serum lead, arsenic, and cadmium levels were estimated using the Varian AA 240FS atomic spectrometer in an acetylene-air ﬂame. Results. The median RBC (4.49 vs. 4.92 × 1012/L), haemoglobin (12.50 vs. 13.70 g/dL), and platelet (220.00 vs. 268.00) counts were signiﬁcantly lower in cases. A signiﬁcantly higher proportion of cases were classiﬁed as anaemic or having microcytic cells compared to controls. Also, serum urea (4.08 vs. 3.41; p � 0.0009), creatinine (108.10 vs. 101.10; p � 0.0286), and BUN : CRE ratio (19.75 vs. 17.84) were signiﬁcantly higher in cases. Additionally, 18.1% of cases were classiﬁed as having moderately reduced renal function compared to only 6.6% of controls. Moreover, a signiﬁcantly higher proportion of cases had detectable serum lead (55.6% vs. 16.4%) and arsenic (53.1% vs. 9.8%) levels compared to controls. However, on average, 80% of agricultural workers did not use personal protective equipment (PPE) when applying agrochemicals; 84.3% of used agro- chemical containments were discarded near the river/canal. Conclusion. Neglect of the use of PPE may be predisposing the agrochemical workers and community to lead and arsenic bioaccumulation with a consequent reduced haematological and renal function.

Source: UCC
High Iodine Deficiency among Pregnant Women in Periurban Ghana: A Hospital-Based Longitudinal Study

Background. Iodine deﬁciency causes maternal hypothyroidism which can lead to growth, cognitive, and psychomotor deﬁcit in neonates, infants, and children. This study examined the iodine status of pregnant women in a periurban setting in Ghana. Methods. This longitudinal study recruited 125 pregnant women by purposeful convenience sampling from the antenatal clinic of the Sefwi Wiawso municipal hospital in Ghana. Urinary iodine concentration (UIC) was estimated by the ammonium persulfate method at an estimated gestational age (EGA) of 11, 20, and 32 weeks. Demographic information, iodized salt usage, and other clinical information were collected using a questionnaire. Results. The prevalence of iodine deﬁciency among the pregnant women was 47.2% at EGA 11 and 60.8% at both EGA of 20 and 32, whereas only 0.8% of participants not using iodized salt had iodine suﬃciency at EGA 32. 18.4%, 20%, and 24% of participants using iodized salt had iodine suﬃciency at EGA 11, 20, and 32, respectively. Conclusion. A high prevalence of iodine deﬁciency was observed among our study cohort.

Source: UCC
High Plasma Levels of Soluble Intercellular Adhesion Molecule (ICAM)-1 Are Associated with Cerebral Malaria

Background: Cerebral malaria (CM) is responsible for most of the malaria-related deaths in children in sub-Saharan Africa. Although, not well understood, the pathogenesis of CM involves parasite and host factors which contribute to parasite sequestration through cytoadherence to the vascular endothelium. Cytoadherence to brain microvasculature is believed to involve host endothelial receptor, CD54 or intercellular adhesion molecule (ICAM)-1, while other receptors such as CD36 are generally involved in cytoadherence of parasites in other organs. We therefore investigated the contributions of host ICAM-1 expression and levels of antibodies against ICAM-1 binding variant surface antigen (VSA) on parasites to the development of CM. Methodology/Principal Findings: Paediatric malaria patients, 0.5 to 13 years were recruited and grouped into CM and uncomplicated malaria (UM) patients, based on well-defined criteria. Standardized ELISA protocol was used to measure soluble ICAM-1 (sICAM-1) levels from acute plasma samples. Levels of IgG to CD36- or ICAM-1-binding VSA were measured by flow cytometry during acute and convalescent states. Wilcoxon sign rank-test analysis to compare groups revealed association between sICAM-1 levels and CM (p,0.0037). Median levels of antibodies to CD36-binding VSA were comparable in the two groups at the time of admission and 7 days after treatment was initiated (p.0.05). Median levels of antibodies to CD36-binding VSAs were also comparable between acute and convalescent samples within any patient group. Median levels of antibodies to ICAM-1-binding VSAs were however significantly lower at admission time than during recovery in both groups. Conclusions/Significance: High levels of sICAM-1 were associated with CM, and the sICAM-1 levels may reflect expression levels of the membrane bound form. Anti-VSA antibody levels to ICAM-binding parasites was more strongly associated with both UM and CM than antibodies to CD36 binding parasites. Thus, increasing host sICAM-1 levels were associated with CM whilst antibodies to parasite expressing non-ICAM-1-binding VSAs were not.

Source: UCC
High prevalence of hepatitis B and poor knowledge on hepatitis B and C viral infections among barbers: a cross-sectional study of the Obuasi municipality, Ghana

Background: Barbers, while shaving, may be accidentally exposed to the blood and bodily fluids of their customers increasing their risk of contraction of HBV and HCV infections. Hence, this study aimed at examining the prevalence and knowledge of barbers on HBV and HCV infections in the Obuasi municipality of Ghana. Methods: A work place based cross-sectional study was conducted from January to April 2015 at the Obuasi municipality in the Ashanti Region of Ghana. Two hundred (200) barbers were conveniently recruited and blood sample of each participant collected for the detection of HBsAg and HCV antibodies. Data on socio demographic characteristics, and knowledge on HBV and HCV infections were collected using a structured and pre-tested questionnaire. Analysis was performed using SPSS version 16.0, and P < 0.05 was considered statistically significant. Results: The prevalence of HBV and HCV among the barbers were 14.5 % and 0.5 % respectively. HBV was highest among barbers within 20–29 years (58.6 %). Majority (90.5 %) of the participants had heard of HBV infection before. The mode of transmission of HBV was unknown by 64.5 % of the participants and 64.0 % did not perceive themselves to be at risk for HBV. Most of the participants had never heard of HCV infection (61.3 %), and unaware of any mode of transmission of HCV (97.0 %). The radio was the major source of information on HBV (57.5 %) and HCV (25.0 %) infections. Conclusion: High prevalence of HBV and low knowledge on HBV and HCV infections was found among barbers. Barbers need to be educated on viral hepatitis to reduce the acquisition of HBV and HCV infections

Source: UCC
High prevalence of PfCRT K76T mutation in Plasmodium falciparum isolates in Ghana

Plasmodium falciparum has successfully developed resistance to almost all currently used antimalarials. A single nucleotide polymorphism in the P. falciparum chloroquine resistance transporter (Pfcrt) gene at position 76 resulting in a change in coding from lysine to threonine (K76T) has been implicated to be the corner stone of chloroquine resistance. Widespread resistance to chloroquine in endemic regions led to its replacement with other antimalarials. In some areas this replacement resulted in a reversion of the mutant T76 allele to the wild-type K76 allele. This study was conducted to determine the prevalence of the K76T mutation of the Pfcrt gene eight years after the ban on chloroquine sales and use. A cross-sectional study was conducted in 6 regional hospitals in Ghana. PCR-RFLP was used to analyse samples collected to determine the prevalence of Pfcrt K76T mutation. Of the 1318 participants recruited for this study, 246 were found to harbour the P. falciparum parasites, of which 60.98% (150/246) showed symptoms for malaria. The prevalence of the Pfcrt T76 mutant allele was 58.54% (144/246) and that of the K76 wild-type allele was 41.46% (102/246). No difference of statistical signiﬁcance was observed in the distribution of the alleles in the symptomatic and asymptomatic participants (P = 0.632). No signiﬁcant association was, again, observed between the alleles and parasite density (P = 0.314), as well as between the alleles and Hb levels of the participants (P = 0.254). Notwithstanding the decline in the prevalence of the Pfcrt T76 mutation since the antimalarial policy change in 2004, the 58.54% prevalence recorded in this study is considered high after eight years of the abolishment of chloroquine usage in Ghana. This is in contrast to ﬁndings from other endemic areas where the mutant allele signiﬁcantly reduced in the population after a reduction chloroquine use.

Source: UCC
High prevalence of PfCRTK76T mutationin Plasmodium falciparum isolates in Ghana

Plasmodium falciparum has successfully developed resistance to almost allcurrently used antimalarials. A single nucleotide polymorphism in the P. falciparum chloroquine resistance transporter (Pfcrt) gene at position 76 resulting in a change in coding from lysine to threonine (K76T)has been implicated to be the corner stone of chloroquine resistance. Widespread resistance to chloroquine in endemic regions led to its replacement with other antimalarials. In some areas this replacement resulted in a reversion of the mutant T76 allele to the wild-typeK76 allele. This study was conducted to determine the prevalence of the K76T mutation of the Pfcrtgene eight years after the ban on chloroquine sales and use. A cross-sectional study was conducted in 6 regional hospitals in Ghana.PCR-RFLP was used to analyze samples collected to determine the prevalence ofPfcrtK76T mutation. Of the 1318 participants recruited for this study, 246 were found to harbour the P. falciparum parasites, of which 60.98% (150/246) showed symptoms for malaria. The prevalence of the PfcrtT76 mutant allele was 58.54% (144/246) and that of the K76 wild-type allele was 41.46% (102/246).No difference of statistical significance was observed in the distribution of the alleles in the symptomatic and asymptomatic participants (P = 0.632).No significant association was, again, observed between the alleles and parasite density (P = 0.314),as well as between the alleles and Hb levels of the participants (P = 0.254).Notwithstanding the decline in the prevalence of the PfcrtT76 mutation since the antimalarialpolicy change in 2004,the 58.54% prevalence recorded in this study is considered high after eight years of the abolishment of chloroquine usage in Ghana. This is in contrast to findings from other endemic areas where the mutant allele significantly reduced in the population after a reduction chloroquine use

Source: UCC
High Prevalence of Plasmodium Falciparum Drug Resistance Markers in Ghana, An Artemisinin-Based Combination Therapy (Act) Setting

Resistance to the artemisinins has been reported in less than a decade after their global deployment. The molecular markers for artemisinin resistance, however, have not been clearly characterized. The aim of this study is to determine and describe the genetic polymorphisms of the Pfcrt, Pfmdrl, and PfATPase6 genes as associated to artemisinin resistance. A total of 1,318 subjects were recruited for the study. A 12.75% prevalence of malaria was recorded. Malaria transmission was not found to be seasonal. PCR-RFLP was employed to analyze mutations at codon positions 76 of the Pfcrt gene as well as positions 86 and 184 of the Pfmdrl gene which have been associated with artemisinin resistance. These mutations were found in very high prevalence among 246 cases of 1,318 subjects recruited for the study. Mutations in the PfATPase6 gene were analyzed by PCR-RFLP and Sequencing. The SNPs of PfATPase6 gene that are said to confer resistance to artemisinins were not found in this study, like in many others, suggesting a growing irrelevance of the PfATPase6 gene as a marker for artemisinin resistance. Two novel SNPs in the PfATPase6 gene were, however, discovered confirming the highly diverse nature of this gene. With the current artemisinin drug pressure and the observed high prevalence of SNPs associated with artemisinin resistance, it is only a matter of time for a stable drug resistance to be recorded in Ghana. A national programme to monitor the development of resistance to artemisinin is, thus, crucially needed.

Source: UCC
High repetition-rate laser z-scan measurements: criterion for recognizing adverse thermal effects

This study reports z-scan measurements in which high-repetition-rate and reduced repetition-rate (pulse-picked) laser beams were employed using a standard sample, carbon disulfide (CS2) contained in supposedly high damage-threshold spectroscopic-grade pristine fused-quartz cuvettes. The results suggest that at reduced repetition rates, the closed aperture z-scan profile for CS2 displays the expected configuration. However, at high repetition-rates the closed aperture z-scans are distinctly different resulting in unexpectedly large nonlinear refractive index of CS2 due to thermal effects that resulted in below-threshold laser-induced damage of the cuvettes. Normaski microscope images confirm the damage and open aperture z-scan study of the damaged fused-quartz cuvettes yielded about two orders of magnitude enhancement in the nonlinear absorption coefficient of silica. Based on these findings, the necessary criterion for recognizing below-threshold laser-induced damage in any high-repetition-rate laser z-scan measurement has been formulated in order to help avoid erroneous interpretation of the origin and strength of nonlinear response in such studies

Source: UCC
High Risk of Coagulopathy among Type-2 Diabetes Mellitus Clients at a Municipal Hospital in Ghana

Persistent hyperglycaemia in diabetes mellitus causes coagulopathies due to glycation of haemoglobin, prothrombin, fibrinogen and other proteins involved in the clotting mechanism. Shortened activated partial thromboplastin time (APTT) and prothrombin time (PT) reflect hypercoagulable state, which is associated with an increased thrombotic risk and adverse cardiovascular effects. This study assessed the coagulation profile of type 2 diabetes mellitus (T2DM) clients at a municipal hospital in Ghana. Methods: A hospital-based case-control study was conducted from January to April 2015 at the Agona Swedru Municipal Hospital. Sixty (60) persons with T2DM and 40 without were recruited and screened using appropriate protocols. Blood samples were collected for coagulation and biochemical tests. Demographic and clinical information were collected using pre-tested questionnaire. Data was analyzed with GraphPad Prism version 5. Results: APTT and PT were significantly shorter among patients with T2DM compared to those without (20.88 ± 5.19 v 31.23 ± 5.41, P=0.0001; and 11.03 ± 2.06sec v 14.46 ± 1.86, P=0.0001 respectively). INR was decreased among patients with T2DM compared to those without (0.83 ± 0.18 v 1.13 ± 0.17, P=0.0001). No significant difference was found in platelet count between T2DM and non-diabetics (179.85 ± 66.15×103 /mm3 v 168.55 ± 35.77×103 /mm3, P=0.326). Serum magnesium was lower among the T2DM patients compared to the non-diabetics, while serum ionized calcium was significantly higher among the T2DM patients (P<0.05). Conclusion: Clients with T2DM may have a high coagulation risk evidenced by shortened APTT, PT and a high ionized calcium compared with controls.

Source: UCC