Truncated Edge Cuprous Oxide Cube Architecture for Reduction of Nitrophenols

Truncated cubic Cu-oxide nanocrystals with edge lengths of ca. 600 nm were prepared employing the low-cost copper (II) chloride as the precursor. XRD  revealed that the truncated cubic Cu-oxide nanocrystals are present in both the CuI and Cu0 state. XPS characterisation gives insight into the amount of  each state present in the as-prepared, oxidised, reduced and recovered catalyst species. The catalytic activity of the truncated cubic Cu-oxide nanocrystals  was tested for the reduction of nitrophenols using NaBH4 . After one catalytic cycle of the reduction of 4-nitrophenol, the activity almost  halved. The SEM images revealed that the recovered catalyst showed some disfigurement of the structure, and XPS confirmed the reduction of the CuI to  metallic Cu0

Factors Affecting Teaching and Learning of Square Roots without Calculators in Secondary Schools: A Case Study of 6 Secondary Schools in Mpika District, Zambia

This study was undertaken to determine the factors affecting the teaching and learning of square roots of real numbers without the calculators in secondary schools in Mpika District. Three research questions were raised and answered by administering questionnaires. Data was collected by means of four different questionnaires administered to twenty one teachers of mathematics, six Heads of Mathematics Department and one hundred and seventy four pupils drawn from six secondary schools in Mpika District. The five points Likert rating scale was used in determining the factors. Data was analyzed using simple frequency counts, percentages and analysis of variance. The results of the study showed that lack of content knowledge among the teachers, lack of educational materials and library facilities were the factors responsible for not teaching the topic without the calculators. For the pupils, it was due to lack of appropriate mathematics text books, not being taught by the teachers and failure to be given at the beginning of the term the  course outline of the mathematics topics to be taught in the term. Some strategies have been adopted to enhance the teaching and learning of square roots without the calculators and a number of recommendations have been made to the government and other stakeholders involved in the provision of education. Keywords: Teaching, learning, square roots, secondary schools, algorithm, calculato

Genetic diversity of proprietary inbred lines of sunflower, determined by mapped SSR markers and total protein analysis.

Thesis (Ph.D)-University of KwaZulu-Natal, Pietermaritzburg, 2008.This study compared DNA based SSR markers with total seed protein markers, used to evaluate genetic diversity of sunflower. The multiplex-ability, cost effectiveness and applicability of microsatellites as molecular markers for a genetic diversity study were investigated and evaluated based on pedigree data of the sunflower germplasm. A solution for oil and fat interference in ultrathin iso-electric focusing gels was investigated, in order to make imaging and interpretation easier and clearer. Total protein analysis was utilized for the determination of genetic diversity on the same inbred material used for the DNA analysis. Finally a correlation is made between the data obtained on DNA vs Protein compared with phenotype and expected pedigree data. A set of 73 SSR markers with known mapped positions were utilized to determine genetic similarity in a group of sunflower inbred lines. Cluster analysis of genetic similarity revealed an excellent correlation with the breeding background and source information obtained from breeders on all inbred lines used in this study. Cluster analysis gave a clear differentiation between B and R-lines, showing clearly defined heterotic groups of the proprietary set of inbred lines. The most outstanding single-locus SSR markers in the set used for this study were identified and used as a core set. Multiplex assays were designed and optimized for the most cost and time effective method for rapid variety identification. The selected markers produced robust PCR products, amplified a single locus each, were polymorphic among the elite inbred lines and supplied a good, genome-wide framework of completely co-dominant, single-locus DNA markers for molecular breeding. The use of a fluorescent-tailed primer technique resulted in a considerable cost saving. Furthermore, the SSR markers can be multiplexed through optimization, in order to avoid undesirable primer-primer interactions and non-specific amplification. First stage iso-electric focusing of total protein extracts were used to analyze sunflower looking at genetic purity and genetic variety verification on diverse sunflower germplasm. Severe visual interference was visible on most seed storage protein extracts of sunflower. This interference was visible as a distortion in the gel matrix on the anodal end of the gel, and caused important proteins to denature in the presence of heightened field strength and the absence of a uniform matrix. Adjustment of the extraction solutions removed this interference. Total protein profiles were generated with the use ultrathin layer iso-electric focusing (UTLIEF) to assess the level of genetic diversity on the same set of sunflower lines used for the SSR analysis. Finally, the genetic diversity of the sunflower germplasm was analysed by comparing proteomic, genomic and pedigree data from the same germplasm. A total of 295 alleles were amplified with a set of 73 SSR markers with known mapped positions. These were utilized to determine the genetic relatedness of a group of B-lines and R-lines of sunflower. In parallel, a total of 68 protein bands were visualized using protein samples of two types of seed storage proteins derived from exactly the same sunflower lines. Cluster analysis clearly differentiated between the B-lines and R-lines, identifying defined heterotic groups of this proprietary set of lines. The comparison of DNA and protein data for the application of genetic diversity studies is analysed, as well as the general comparison on the use of the two different molecules as markers

Synthesis and Anchoring of Antineoplastic Ferrocene and Phthalocyanine Derivatives on Water-Soluble Polymeric Drug Carriers Derived from Lysine and Aspartic Acid

The general synthetic strategy towards water-soluble biodegradable drug carriers and the properties that they must have are discussed. The syntheses of water-soluble biodegradable copolymers of lysine and aspartic acid as potential drug-delivering devices, having amine-functionalised side chains are then described. Covalent anchoring of carboxylic acid derivatives of the antineoplastic ferrocene and photodynamically active phthalocyanine moieties to the amine-containing drug carrier copolymers under mild coupling conditions has been achieved utilising the coupling reagent O-benzotriazolyl-N,N,N′,N′-tetramethyluronium hexafluorophosphate to promote formation of the biodegradable amide bond. Even though the parent antineoplastic ferrocene and phthalocyanine derivatives are themselves insoluble in water at pH < 7, the new carrier-drug conjugates that were obtained are well water-soluble

Comparison of equations for estimating glomerular filtration rate in screening for chronic kidney disease in asymptomatic black Africans: A cross sectional study

Background: Several equations have been developed to estimate glomerular filtration rate (eGFR). The common equations used were derived from populations predominantly comprised of Caucasians with chronic kidney disease (CKD). Some of the equations provide a correction factor for African-Americans due to their relatively increased muscle mass and this has been extrapolated to black Africans. Studies carried out in Africa in patients with CKD suggest that using this correction factor for the black African race may not be appropriate. However, these studies were not carried out in healthy individuals and as such the extrapolation of the findings to an asymptomatic black African population is questionable. We sought to compare the proportion of asymptomatic black Africans reported as having reduced eGFR using various eGFR equations. We further compared the association between known risk factors for CKD with eGFR determined using the different equations. Methods: We used participant and laboratory data collected as part of a global reference interval study conducted by the Committee of Reference Intervals and Decision Limits (C-RIDL) under the International Federation of Clinical Chemistry (IFCC). Serum creatinine values were used to calculate eGFR using the Cockcroft-Gault (CG), re-expressed 4 variable modified diet in renal disease (4v–MDRD), full age spectrum (FAS) and chronic kidney disease epidemiology collaboration equations (CKD-EPI). CKD classification based on eGFR was determined for every participant. Results: A total of 533 participants were included comprising 273 (51.2%) females. The 4v–MDRD equation without correction for race classified the least number of participants (61.7%) as having an eGFR equivalent to CKD stage G1 compared to 93.6% for CKD-EPI with correction for race. Only age had a statistically significant linear association with eGFR across all equations after performing multiple regression analysis. The multiple correlation coefficients for CKD risk factors were higher for CKD-EPI determined eGFRs. Conclusions: This study found that eGFR determined using CKD-EPI equations better correlated with a prediction model that included risk factors for CKD and classified fewer asymptomatic black Africans as having a reduced eGFR compared to 4v–MDRD, FAS and CG corrected for body surface area

Electrochemical study of chromium(0) Fischer carbene complexes : trends in redox potential

It is illustrated that the electrochemical redox potentials of chromium(0) Fischer carbene complexes containing a heteroaromatic substituent can be determined to a high degree of accuracy from the gas phase density functional theory (DFT) optimized frontier orbital energies, with a mean average error of the calculated redox potentials of 0.047 V for the chromium-based oxidation potential and 0.057 V for the carbene ligand based reduction potential. For the first time it was possible to distinguish between the Cr0/I oxidation peaks of the E and the Z-isomer of a cyclohexylamino pentacarbonyl chromium Fischer carbene complex, namely [(CO)5CrC(NHCy)(2-thienyl)]. The linear relationship obtained between the oxidation potential and the DFT calculated highest molecular orbital energies, made it possible to assign the oxidation peak at the lower less positive oxidation potential to the oxidation of the E isomer, and the peak at the slightly higher (more positive) oxidation potential to the oxidation of the Z isomer of [(CO)5CrC(NHCy)(2-thienyl)].The South African National Research Foundation (JC, ML), the Central Research Fund of the University of the Free State, Bloemfontein, South Africa (JC, EE) and the University of Pretoria, Pretoria, South Africa (ML).http://www.elsevier.com/locate/poly2018-05-08Chemistr

Synthesis and XPS characterization of Si-supported chromium(0) Fischer aminocarbene complexes

Ethoxy chromium (0) Fischer carbene pentacarbonyl complexes [(CO)5CrC(OEt)R]; R = 2- thienyl (1), 2-furyl (2) were covalently anchored onto aminopropyltrimethoxysilanefunctionalised silicon-wafers to form Cr-grafted Si-wafers S1 and S2 that were characterized by X-ray photoelectron spectroscopy (XPS). X-ray photoelectron spectroscopy determined that binding energy of the Cr 2p3/2 photoelectron line of the thienyl-containing complexes were smaller than that of the furyl-containing complexes. The binding energy of the Cr 2p3/2 photoelectron line of the ethoxycarbene complexes was smaller than that of aminocarbenes. The binding energy of the Cr 2p3/2 photoelectron line of the Cr-grafted Si-wafers were ca. 1 eV higher than that of the related aminocarbenes. A 25 – 33 % anchoring of the Crcomplexes 1 and 2 on the aminopropyltrimethoxysilane-functionalised silicon-wafers was achieved.The South African National Research Foundation (JC, ML), the Central Research Fund of the University of the Free State, Bloemfontein, South Africa (JC, EE) and the University of Pretoria, Pretoria, South Africa (ML).http://www.elsevier.com/locate/jorganchem2018-05-31hb2017Chemistr

Metabolic syndrome and its predictors in an urban population in Kenya: A cross sectional study

Background: The metabolic syndrome (MetS) is a clustering of interrelated risk factors which doubles the risk of cardio-vascular disease (CVD) in 5–10 years and increases the risk of type 2 diabetes 5 fold. The identification of modifiable CVD risk factors and predictors of MetS in an otherwise healthy population is necessary in order to identify individuals who may benefit from early interventions. We sought to determine the prevalence of MetS as defined by the harmonized criteria and its predictors in subjectively healthy black Africans from various urban centres in Kenya. Method: We used data collected from healthy black Africans in Kenya as part of a global study on establishing reference intervals for common laboratory tests. We determined the prevalence of MetS and its components using the 2009 harmonized criterion. Receiver operator characteristic (ROC) curve analysis was used to determine the area under the curves (AUC) for various predictors of MetS. Youden index was used to determine optimum cut-offs for quantitative measurements such as waist circumference (WC). Results: A total of 528 participants were included in the analysis. The prevalence of MetS was 25.6% (95% CI: 22. 0%–29.5%). Among the surrogate markers of visceral adiposity, lipid accumulation product was the best predictor of MetS with an AUC of 0.880 while triglyceride was the best predictor among the lipid parameters with an AUC of 0.816 for all participants. The optimal WC cut-off for diagnosing MetS was 94 cm and 86 cm respectively for males and females. Conclusions: The prevalence of MetS was high for a healthy population highlighting the fact that one can be physically healthy but have metabolic derangements indicative of an increased CVD risk. This is likely to result in an increase in the cases of CVD and type 2 diabetes in Kenya if interventions are not put in place to reverse this trend. We have also demonstrated the inappropriateness of the WC cut-off of 80 cm for black African women in Kenya when defining MetS and recommend adoption of 86 cm

Complete blood count reference intervals from a healthy adult urban population in Kenya

Background: There are racial, ethnic and geographical differences in complete blood count (CBC) reference intervals (RIs) and therefore it is necessary to establish RIs that are population specific. Several studies have been carried out in Africa to derive CBC RIs but many were not conducted with the rigor recommended for RI studies hence limiting the adoption and generalizability of the results. Method: By use of a Beckman Coulter ACT 5 DIFF CP analyser, we measured CBC parameters in samples collected from 528 healthy black African volunteers in a largely urban population. The latent abnormal values exclusion (LAVE) method was used for secondary exclusion of individuals who may have had sub-clinical diseases. The RIs were derived by both parametric and non-parametric methods with and without LAVE for comparative purposes. Results: Haemoglobin (Hb) levels were lower while platelet counts were higher in females across the 4 age stratifications. The lower limits for Hb and red blood cell parameters significantly increased after applying the LAVE method which eliminated individuals with latent anemia and inflammation. We adopted RIs by parametric method because 90% confidence intervals of the RI limits were invariably narrower than those by the non-parametric method. The male and female RIs for Hb after applying the LAVE method were 14.5-18.7 g/dL and 12.0-16.5 g/dL respectively while the platelet count RIs were 133-356 and 152-443 x10(3) per μL respectively. Conclusion: Consistent with other studies from Sub-Saharan Africa, Hb and neutrophil counts were lower than Caucasian values. Our finding of higher Hb and lower eosinophil counts compared to other studies conducted in rural Kenya most likely reflects the strict recruitment criteria and healthier reference population after secondary exclusion of individuals with possible sub-clinical diseases

Determination of reference intervals for common chemistry and immunoassay tests for Kenyan adults based on an internationally harmonized protocol and up-to-date statistical methods

Background: Due to a lack of reliable reference intervals (RIs) for Kenya, we set out to determine RIs for 40 common chemistry and immunoassay tests as part of the IFCC global RI project. Methods: Apparently healthy adults aged 18–65 years were recruited according to a harmonized protocol and samples analyzed using Beckman-Coulter analyzers. Value assigned serum panels were measured to standardize chemistry results. The need for partitioning reference values by sex and age was based on between-subgroup differences expressed as standard deviation ratio (SDR) or bias in lower or upper limits (LLs and ULs) of the RI. RIs were derived using a parametric method with/without latent abnormal value exclusion (LAVE). Results: Sex-specific RIs were required for uric acid, creatinine, total bilirubin (TBil), total cholesterol (TC), ALT, AST, CK, GGT, transferrin, transferrin saturation (TfSat) and immunoglobulin-M. Age-specific RIs were required for glucose and triglyceride for both sexes, and for urea, magnesium, TC, HDL-cholesterol ratio, ALP, and ferritin for females. LAVE was effective in optimizing RIs for AST, ALT, GGT iron-markers and CRP by reducing influence of latent anemia and metabolic diseases. Thyroid profile RIs were derived after excluding volunteers with anti-thyroid antibodies. Kenyan RIs were comparable to those of other countries participating in the global study with a few exceptions such as higher ULs for TBil and CRP. Conclusions: Kenyan RIs for major analytes were established using harmonized protocol from well-defined reference individuals. Standardized RIs for chemistry analytes can be shared across sub-Saharan African laboratories with similar ethnic and life-style profile