189 research outputs found
Measurement of Single and Double Spin-Flip Probabilities in Inelastic Deuteron Scattering on 12C at 270 MeV
The deuteron single and double spin-flip probabilities, S1 and S2, have been
measured for the 12C(pol{d},pol{d}') reaction at Ed = 270 MeV for an excitation
energy range between 4 and 24 MeV and a scattering angular range between
Theta_lab = 2.5 and 7.5 deg. The extracted S1 exhibits characteristic values
depending on the structure of the excited state. The S2 is close to zero over
the measured excitation energy range. The SFP angular distribution data for the
2+ (4.44 MeV) and 1+ (12.71 MeV) states are well described by the microscopic
DWIA calculations
Rare Mutations of Peroxisome Proliferator-Activated Receptor Gamma: Frequencies and Relationship with Insulin Resistance and Diabetes Risk in the Mixed Ancestry Population from South Africa
Background. Genetic variants in the nuclear transcription receptor, PPARG, are associated with cardiometabolic traits, but reports remain conflicting. We determined the frequency and the clinical relevance of PPARG SNPs in an African mixed ancestry population. Methods. In a cross-sectional study, 820 participants were genotyped for rs1800571, rs72551362, rs72551363, rs72551364, and rs3856806, using allele-specific TaqMan technology. The homeostatic model assessment of insulin (HOMA-IR), ÎČ-cells function (HOMA-B%), fasting insulin resistance index (FIRI), and the quantitative insulin-sensitivity check index (QUICKI) were calculated. Results. No sequence variants were found except for the rs3856806. The frequency of the PPARG-His447His variant was 23.8% in the overall population group, with no difference by diabetes status (). The His447His allele T was associated with none of the markers of insulin resistance overall and by diabetes status. In models adjusted for 2-hour insulin, the T allele was associated with lower prevalent diabetes risk (odds ratio 0.56 (95% CI 0.31â0.95)). Conclusion. Our study confirms the almost zero occurrences of known rare PPARG SNPs and has shown for the first time in an African population that one of the common SNPs, His447His, may be protective against type 2 diabetes
APOL1 genetic variants, chronic kidney diseases and hypertension in mixed ancestry South Africans
BackgroundThe frequencies of apolipoprotein L1 (APOL1) variants and their associations with chronic kidney disease (CKD) vary substantially in populations from Africa. Moreover, available studies have used very small sample sizes to provide reliable estimates of the frequencies of these variants in the general population. We determined the frequency of the two APOL1 risk alleles (G1 and G2) and investigated their association with renal traits in a relatively large sample of mixed-ancestry South Africans. APOL1 risk variants (G1: rs60910145 and rs73885319; G2: rs71785313) were genotyped in 859 African mixed ancestry individuals using allele-specific TaqMan technology. Glomerular filtration rate (eGFR) was estimated using the Modification of Diet in Renal Disease (MDRD) and Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations.ResultsThe frequencies of rs73885319, rs60910145 and rs71785313 risk alleles were respectively, 3.6%, 3.4%, and 5.8%, resulting in a 1.01% frequency of the APOL1 two-risk allele (G1:G1 or G1:G2 or G2:G2). The presence of the two-risk allele increased serum creatinine with a corresponding reduction in eGFR (either MDRD or CKD-EPI based). In dominant and log-additive genetic models, significant associations were found between rs71785313 and systolic blood pressure (both pââ€â0.025), with a significant statistical interaction by diabetes status, pâ=â0.022, reflecting a negative non-significant effect in nondiabetics and a positive effect in diabetics.ConclusionsAlthough the APOL1 variants are not common in the mixed ancestry population of South Africa, the study does provide an indication that APOL1 variants may play a role in conferring an increased risk for renal and cardiovascular risk in this population
Urinary schistosomiasis in communities around Kiri Lake, Shelleng Local Government Area, Adamawa State, Nigeria
The objectives of the study were to determine the prevalence of urinary schistosomiasis in the different communities, the intensity of infection, prevalence among gender and age groups and to relate infection with parentâs occupation. A study on the prevalence of urinary schistosomiasis was conducted in four villages around Kiri Lake in Shelleng Local Government Area, Adamawa State, Nigeria. Two hundred and thirty two urine samples were collected from four primary school children randomly selected from within the four study communities. Overall, prevalence of urinary schistosomiasis was 48% (111/232), with males recording 49% (69/142) and females 47% (42/90). The total mean egg count (MEC) was 8.3. There was no significant difference in prevalence between males and females (PË0.05). Prevalence was higher among age groups, with the 13-15 year old age group having the highest 62.96% (17/27) and the 4-6 year old age group had the least 37% (19/52). There was no statiscally significant difference in prevalence among the different age groups (P>0.05). Infection was also high among children of fishermen 59.09% (13/22), followed by farmersâ children 56.25% (45/80) and the least prevalence was among children of teachers 20% (3/15). Old Banjiram had the highest infection of 91% (21/23), while Kwadadai had the least 36.8% (21/57) (P<0.05). Old Banjiram and children in the 10-12 years age group had the highest mean egg count of 10.6 and 9.4 respectively. The study reveals a high prevalence of urinary schistosomiasis. And therefore portable water source should be made functional in all communities surrounding the lake. While rehabilitation and repair of the existing water borehole system in the community should be effected as well as drilling new additional boreholes to serve their water needs. Commun JASEMity participatory health education on this neglected tropical disease in the area is needed on knowledge of the disease, the intermediate host and transmission pattern. Since school children harbour infection and are a source of infection of schistosomiasis in endemic communities, planning and provision for their treatment should be considered in control programmes.Keywords: Schistosoma haematobium, Prevalence, Kiri lake, Socio-economic, School children, Nigeri
Association of the ENPP1 rs997509 polymorphism with obesity in South African mixed ancestry learners
Background: The Ectonucleotide Pyrophosphatase Phosphodiesterase1 (ENPP1) polymorphisms have been associated with metabolic traits. There is no data on the effect of ENPP1 in South African children or adults. Objective: To investigate the role of K121Q (rs1044498), rs997509 and rs9402349 in obesity and other components of the metabolic syndrome. Design: A case-control study. Subjects: Sixty four obese and 64 lean mixed ancestry learners. Setting: Western Cape, South Africa. Main outcome measure: The EN PP1 rs997509T allele is independently associated with obesity in children of mixed ancestry from South Africa. Results: The T allele frequency of the rs997509 differed significantly between obese and controls, p=0.0100 and increased the risk of being obese, p = 0.0238. Furthermore, the estimated effect of the T allele was an increase of 8.6 cm in waist circumference, 10.2 kg in weight and a corresponding 4.9 kg/m2 in BMI. Individuals carrying both the 121Q and the T allele of rs997509 were more associated with obesity (odds ratio = 3.85, 95% CI: 1.13 to 13.09) whilst those carrying the C allele of rs997509 in the presence of 121Q were likely to be lean with odds ratio of obesity 0.41 (95% CI: 0.19 to 0.87). Conclusion: Our findings suggest that ENPP1 polymorphisms may contribute to different metabolic characteristics, all of which are associated with insulin resistance in mixed ancestry children of South Africa. However, a larger study is required to confirm findings of this study.East African Medical Journal Vol. 87 No. 8 August 201
Determination of the Gamow-Teller Quenching Factor from Charge Exchange Reactions on 90Zr
Double differential cross sections between 0-12 degrees were measured for the
90Zr(n,p) reaction at 293 MeV over a wide excitation energy range of 0-70 MeV.
A multipole decomposition technique was applied to the present data as well as
the previously obtained 90Zr(p,n) data to extract the Gamow-Teller (GT)
component from the continuum. The GT quenching factor Q was derived by using
the obtained total GT strengths. The result is Q=0.88+/-0.06 not including an
overall normalization uncertainty in the GT unit cross section of 16%.Comment: 11 papes, 4 figures, submitted to Physics Letters B (accepted),
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Optimal waist-to-height ratio values for cardiometabolic risk screening in an ethnically diverse sample of South African urban and rural school boys and girls
BACKGROUND: The proposed waist-to-height ratio (WHtR) cut-off of 0.5 is less optimal for cardiometabolic risk screening in children in many settings. The purpose of this study was to determine the optimal WHtR for children from South Africa, and investigate variations by gender, ethnicity and residence in the achieved value. METHODS: Metabolic syndrome (MetS) components were measured in 1272 randomly selected learners, aged 10-16 years, comprising of 446 black Africans, 696 mixed-ancestry and 130 Caucasians. The Youden's index and the closest-top-left (CTL) point approaches were used to derive WHtR cut-offs for diagnosing any two MetS components, excluding the waist circumference. RESULTS: The two approaches yielded similar cut-off in girls, 0.465 (sensitivity 50.0, specificity 69.5), but two different values in boys, 0.455 (42.9, 88.4) and 0.425 (60.3, 67.7) based on the Youden's index and the CTL point, respectively. Furthermore, WHtR cut-off values derived differed substantially amongst the regions and ethnic groups investigated, whereby the highest cut-off was observed in semi-rural and white children, respectively, Youden's index0.505 (31.6, 87.1) and CTL point 0.475 (44.4, 75.9). CONCLUSION: The WHtR cut-off of 0.5 is less accurate for screening cardiovascular risk in South African children. The optimal value in this setting is likely gender and ethnicity-specific and sensitive to urbanization
Analyzing powers Ayy, Axx, Axz and Ay in the dd->3Hen reaction at 270 MeV
The data on the tensor Ayy, Axx, Axz and vector Ay analyzing powers in the
dd->3Hen obtained at Td= 270 MeV in the angular range 0 - 110 degrees in the
c.m. are presented. The observed negative sign of the tensor analyzing powers
Ayy, Axx and Axz at small angles clearly demonstrate the sensitivity to the
ratio of the D and S wave component of the 3He wave function. However, the
one-nucleon exchange calculations by using the standard 3He wave functions have
failed to reproduce the strong variation of the tensor analyzing powers as a
function of the angle in the c.m.Comment: 8 pages, 7 figures, 4 tables. Submitted to EPJ
Performance of the neutron polarimeter NPOL3 for high resolution measurements
We describe the neutron polarimeter NPOL3 for the measurement of polarization
transfer observables with a typical high resolution of 300 keV
at 200 MeV.
The NPOL3 system consists of three planes of neutron detectors.
The first two planes for neutron polarization analysis are made of 20 sets of
one-dimensional position-sensitive plastic scintillation counters with a size
of 100 cm 10 cm 5 cm, and they cover the area of 100
100 .
The last plane for detecting doubly scattered neutrons or recoiled protons is
made of the two-dimensional position-sensitive liquid scintillation counter
with a size of 100 cm 100 cm 10 cm.
The effective analyzing powers and double scattering
efficiencies were measured by using the three kinds
of polarized neutrons from the , , and reactions at = 198 MeV.
The performance of NPOL3 defined as
are similar to that of the
Indiana Neutron POLarimeter (INPOL) by taking into account for the counter
configuration difference between these two neutron polarimeters.Comment: 28 pages, 18 figures, submitted to Nucl. Instrum. Methods Phys. Res.
Precision measurement of vector and tensor analyzing powers in elastic deuteron-proton scattering
High precision vector and tensor analyzing powers of elastic deuteron-proton
d+p scattering have been measured at intermediate energies to investigate
effects of three-nucleon forces (3NF). Angular distribution in the range of
70-120 degree in the center-of mass frame for incident-deuteron energies of 130
and 180 MeV were obtained using the RIKEN facility. The beam polarization was
unambiguously determined by measuring the 12C(d,alpha)10B(2+) reaction at 0
degree. Results of the measurements are compared with state-of-the-art
three-nucleon calculations. The present modeling of nucleon-nucleon forces and
its extension to the three-nucleon system is not sufficient to describe the
high precision data consistently and requires, therefore, further
investigation
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