Studies on some VO(IV), Ni(II) and Cu(II) complexes of non-symmetrical tetradentate Schiff-bases

The coordination chemistry of VO(IV), Ni(II) and Cu(II) with unsymmetrical Schiff base ligands, [HO(OCH3)C6H3C(CH3):N(CH2CH2)N:C(CH3)CH:C(C6H5)OH], H2L and [HO(OCH3)C6H3C(CH3):N(CH2CH2)N:C(CH3)CH:C(CH3)OH], H2L1 (derived from condensation of 1-phenyl-1,3-butanedione/2,4-pentanedione, ethylenediamine and 5-methoxy-2-hydroxy acetophenone) is discussed. The metal complexes were characterized by elemental analysis, molar conductance, magnetic susceptibility, infrared and electronic spectral measurements. They are magnetically dilute, non-electrolytes in nitromethane. The ligands are tetradentately coordinating via the imine N and enolic O atoms, resulting in 5-coordinate square-pyramidal geometry for the VO(IV) complexes and 4-coordinate square-planar geometry for the Ni(II) and Cu(II) complexes. The assignment of geometry is supported by magnetic and spectral measurements. KEY WORDS: Coordination chemistry, Magnetically dilute, Non-electrolyte, Non-symmetrical Schiff base  Bull. Chem. Soc. Ethiop. 2008, 22(2), 219-224

Synthesis, spectroscopic characterization, in-vitro antibacterial and antiproliferative activities of some metal(II) complexes of 3,4-dihydronaphthalen-1(2H)-one Schiff base

The Schiff base, 3-hydroxy-4-{[4-(methylsulfanyl)phenyl]imino}-3,4-dihydronaphthalen-1(2H)-one, and its Mn(II), Co(II), Ni(II), Cu(II), Zn(II) and Pd(II) complexes have been synthesized and characterized by microanalysis, conductance, 1H NMR, infrared and electronic spectral measurements. The ligand exists in the ketoimine form in chloroform, and in the enolimine form in the solid state, as shown by 1H NMR and IR spectroscopies. The ligand coordinates to the metal ions in the ratio 1:1, using NO chromophores forming complexes of the type [MLNO3]H2O, with the exception of the Zn(II) and Pd(II) complexes. Electronic measurements are indicative of a four coordinate square-planar geometry for all the complexes, except for the Cu(II) and Zn(II) complexes which assume a tetrahedral geometry. None is an electrolyte in nitromethane. The ligand and the metal complexes are air–stable, but decomposed on heating at 120 °C and in the range 150-156 °C respectively. The antibacterial studies reveal that the Co(II) and the Cu(II) complexes exhibit broad-spectrum activity against Proteus mirabilis, Escherichia coli and Staphylococcus aureus with inhibitory zones range of 14.0-22.0 and 13.0-25.0 mm respectively. The antiproliferative studies show that the Zn(II) complex has the best in-vitro anticancer activity against both HT-29 (colon) carcinoma and MCF-7 (human breast) adenocarcinoma with IC50 values of 6.46 μm and 3.19 μm, which exceeds the activity of Cis-platin by 8 % and 63 % respectively

ON THE IDENTIFICATION OF CORE DETERMINANTS OF POVERTY: A LOGISTIC REGRESSION APPROACH

This study carried out a logistic regression modelling of poverty status of households in Nigeria to identify possible determinants of poverty using the 2003/2004 National Living Standard Survey (NLSS) data. This approach differs from classical regression methods that place inappropriate restrictions on the residuals of the model. The results of the logistic regression showed that household size and educational group for highest level attained by the household head were the most significant determinants of poverty. Others include sex of the household head, age in years of the household head, father’s education level, father’s work, mother’s work, and occupation group of the household head. It strongly recommends that moderate household size and acquiring of formal education be encouraged to reduce poverty prevalence. Keywords: poverty incidence, multidimensional concept, lack of representation and freedom, household's consumption expenditure, classical  regression methods, logistic regression mode

Censored Foster Greer Thorbecke (FGT) indexes in poverty analysis in Nigeria

This study is an attempt to assess the prospects of censoring in one-dimensional poverty analysis in Nigeria. The conventional method involves truncation of the non-poor households and this often leads to measurement error. Censoring instead of truncation was considered using data from the Nigeria General Household Survey (NGHS) Panel Survey. The estimated poverty indices obtained via censoring gave higher precision estimates compared to the indices obtained traditionally. This finding implies that censoring could reduce the problem of measurement error involved in the traditional poverty analytical procedures.Keywords: Censoring, Measurement error. One-dimensional, Poverty analysis, Poverty indice

Optimization of some selected process factors in wheat production: A response surface approach

This study applied the approach of Response Surface Methodology to optimize some selected process factors in wheat production in order to minimize the amount of wheat harvest loss using combine harvester. The factors considered were Grain Moisture Content (GMC), Rotor Speed (RS) and Ground Speed (GS) of the combine harvester. The amount of wheat loss was evaluated in different levels of GMC (10, 15 and 20 %), RS (450, 550 and 650 rpm) and GS (3.5, 4.5 and 5.5 km/h) and the relationship between the specified factors and the amount of wheat harvest loss was established. The study revealed that the 2-factor interaction model with coefficient of multiple determination (R^2) and adjusted coefficient of multiple determination (R ̅^2) of 79.5% and 76.88% respectively and an insignificant lack of fit (p value of 0.289) best predicts the wheat harvest loss using combine harvester. In the canonical analysis, the Eigenvalues were 10.83, 4.46 and 1.21 which shows that the points 15% for grain moisture content, 650 rpm for rotor speed and 3.5km/h for machine ground speed are points of minimization which give the least wheat harvest loss. The 3-D surface plot for the wheat harvest loss gave a concave up image justifying the points of minimization obtained. The farmer will recover at least 66kg of wheat per hectare if the recommended factor combination is applied

Proxy Means Test (PMT) analysis of poverty in Oyo State

This study attempts an assessment of the effectiveness of the proxy means test (PMT) procedure in achieving better targeting of the poor in Oyo State, Nigeria. This is because proper identification and corresponding targeting of the poor is still a challenge in poverty analysis in Africa. The PMT method was therefore used to estimate household expenditures, corresponding poverty statuses of the households, inclusion and exclusion rates using data from the National Living Standard Survey (NLLS) for the five poverty lines considered. The PMT method gave higher percentages of the poor compared to the conventional method for all the five poverty lines. The implication of this finding is that the PMT method could indeed be used alternatively for improved targeting of the poor, especially in Oyo State.Keywords: Poverty, Proxy Means Test (PMT), Poverty lines, Oyo State, Afric

Two Stage Robust Ridge Method in a Linear Regression Model

Two Stage Robust Ridge Estimators based on robust estimators M, MM, S, LTS are examined in the presence of autocorrelation, multicollinearity and outliers as alternative to Ordinary Least Square Estimator (OLS). The estimator based on S estimator performs better. Mean square error was used as a criterion for examining the performances of these estimators

Effect of hemodialysis on the hearing function of patients with chronic renal failure

Sensorineural hearing impairment (SHI) has been reported in chronic renal failure (CRF) patients with a prevalence of 20-40%. The aetiopathogenetic mechanisms reported included osmotic alteration resulting in loss of hair cells and in some, complications of haemodialysis have been hypothesized. We have in the past reported 2 cases of CRF patients who developed acute SHL following hemodialysis. This is a report of investigation of the effect of hemodialysis on the hearing function of CRF patients using pure tone audiometry findings. Thirty-three CRF patients were recruited for Pure Tone Audiometry (PTA) at admission and after three sessions of hemodialysis. The pure tone audiometry was done with a computer audiometer BA 20 Kamplex in the sound - proof (acoustic) booth in the ENT clinic. The duration of illness, dosage of diuretics and blood pressure were also noted. Similar age and sex-matched control were selected among volunteers who were otherwise clinically healthy. The data was processed using the Statistical Package for the Social Sciences (SPSS Inc, Chicago, Illinois, USA). Thirty-three CRF patients treated with haemodialysis and 28 healthy controls completed the study, 34 males and 27 females, age range was 16 - 72 years, mean of 45.30 (SD16.20) for subjects and 49.7 for controls. Hearing loss was found in 22/34 (67%) at recruitment and 27/34 (79%) after 3 sessions of hemodialysis. There was a significant difference between the mean pre- and post-hemodialysis PTA values, P =0.0008. There was also a significant correlation between post - hemodialysis hearing threshold and (i) duration of illness (P = 0.00340) and (ii) creatinine levels of the patients (P=0.035). In conclusion, there was a significant depression in the hearing threshold of patients with CRF following three sessions of hemodialysis. This could be caused by changes induced by hemodialysis or effects of the duration and severity of disease. African Journal of Health Sciences Vol. 13 (3-4) 2006: pp. 29-3

Synthesis, characterization, DNA-binding and biological activity of Zn(II) complexes of sulfadiazine with different amino acids

New Zn(II) complexes (ZnII-VS, ZnII-LS, ZnII-SS, ZnII-CS and ZnII-MS) of the sulfonamide antibiotic sulfadiazine with different amino acids were prepared and fully characterized by elemental analyses, thermal analysis and IR, UV/Vis and 1H NMR spectroscopy. The IR and 1H NMR spectral data show that the ligands behave in a dibasic bidentate fashion coordinating to zinc ion. Interactions of these complexes with DNA were investigated by spectrophotometric method. Moreover, the antibacterial and antifungal activities were evaluated for five ligands and their complexes. The computational study for prediction of absorption, distribution, metabolism, elimination and toxic factors (ADMET) properties were performed for the prepared ligands

(Methanol-κO){1-[2-(piperazin-4-ium-1-yl-κN 1)ethyl­imino­methyl-κN]naphthalen-2-olato-κO}bis­(thio­cyanato-κN)nickel(II) methanol monosolvate

In the title solvated complex, [Ni(C17H21N3O)(NCS)2(CH3OH)]·CH3OH, the Ni2+ ion is coordinated by one phenolate O, one imine N, and one amine N atom of the tridentate Schiff base ligand, two thio­cyanate N atoms and one methanol O atom, resulting in a distorted cis-NiO2N4 octa­hedral geometry. The chelate ring formed by the phenolate O and imine N atoms approximates to an envelope with the Ni atom as the flap, whereas the chelate ring formed by the two N atoms is twisted about the C—C bond. In the crystal, the components are linked by O—H⋯O, N—H⋯O, N—H⋯S, and O—H⋯S hydrogen bonds