| 1. |
- Jayasree, R. S., et al.
(författare)
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Raman and infrared spectral analysis of corrosion products on zinc NaZn4Cl(OH)(6)SO4-6H(2)O and Zn4Cl2(OH)(4)SO4 center dot 5H(2)O
- 2006
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Ingår i: Materials Chemistry and Physics. - : Elsevier BV. - 0254-0584 .- 1879-3312. ; 99:03-feb, s. 474-478
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Tidskriftsartikel (refereegranskat)abstract
- Two corrosion products of zinc namely NaZn4Cl(OH)(6)SO4 center dot 6H(2)O which occurs mainly in marine and traffic environments and Zn4Cl2(OH)(4)SO4 center dot 5H(2)O which occurs in industrial, rural and urban environments were analysed using infrared and Raman spectroscopic methods and the vibrational modes of SO42- ion, OH radical and H2O molecules have been identified and discussed. The symmetric stretching vibrations of the SO42- ion of the compounds give an indication of the distorted structure for the SO4 anion in the compounds, the distortion being more in Zn4Cl2(OH)(4)SO4 center dot 5H(2)O. Due to the presence of strong hydrogen bond network, an unusual lowering of the symmetric stretching mode of SO4 is observed in both the compounds. In NaZn4Cl(OH)(6)SO4 center dot 6H(2)O, medium to weak hydrogen bonding network is present while strong to weak hydrogen bonding is present in Zn4Cl2(OH)(4)SO4 center dot 5H(2)O.
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| 2. |
- Klug, Stefanie J, et al.
(författare)
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TP53 codon 72 polymorphism and cervical cancer : a pooled analysis of individual data from 49 studies
- 2009
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Ingår i: The Lancet Oncology. - 1470-2045 .- 1474-5488. ; 10:8, s. 772-784
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Cervical cancer is caused primarily by human papillomaviruses (HPV). The polymorphism rs1042522 at codon 72 of the TP53 tumour-suppressor gene has been investigated as a genetic cofactor. More than 80 studies were done between 1998 and 2006, after it was initially reported that women who are homozygous for the arginine allele had a risk for cervical cancer seven times higher than women who were heterozygous for the allele. However, results have been inconsistent. Here we analyse pooled data from 49 studies to determine whether there is an association between TP53 codon 72 polymorphism and cervical cancer. METHODS: Individual data on 7946 cases and 7888 controls from 49 different studies worldwide were reanalysed. Odds ratios (OR) were estimated using logistic regression, stratifying by study and ethnic origin. Subgroup analyses were done for infection with HPV, ethnic origin, Hardy-Weinberg equilibrium, study quality, and the material used to determine TP53 genotype. FINDINGS: The pooled estimates (OR) for invasive cervical cancer were 1.22 (95% CI 1.08-1.39) for arginine homozygotes compared with heterozygotes, and 1.13 (0.94-1.35) for arginine homozygotes versus proline homozygotes. Subgroup analyses showed significant excess risks only in studies where controls were not in Hardy-Weinberg equilibrium (1.71 [1.21-2.42] for arginine homozygotes compared with heterozygotes), in non-epidemiological studies (1.35 [1.15-1.58] for arginine homozygotes compared with heterozygotes), and in studies where TP53 genotype was determined from tumour tissue (1.39 [1.13-1.73] for arginine homozygotes compared with heterozygotes). Null results were noted in studies with sound epidemiological design and conduct (1.06 [0.87-1.29] for arginine homozygotes compared with heterozygotes), and studies in which TP53 genotype was determined from white blood cells (1.06 [0.87-1.29] for arginine homozygotes compared with heterozygotes). INTERPRETATION: Subgroup analyses indicated that excess risks were most likely not due to clinical or biological factors, but to errors in study methods. No association was found between cervical cancer and TP53 codon 72 polymorphism when the analysis was restricted to methodologically sound studies.
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| 3. |
- Pai, Ranjith Krishna, et al.
(författare)
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Temperature induced formation of strong gels of acrylamide-based polyelectrolyte
- 2009
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Ingår i: Journal of Colloid and Interface Science. - 0021-9797 .- 1095-7103. ; 337, s. 46-53
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Tidskriftsartikel (refereegranskat)abstract
- Very strong physical gels have been formed by moderate temperature increases in aqueous dispersions of acrylamide-based beads and dissolved polymeric molecules. Rheometry, confocal laser scanning microscopy, and differential scanning calorimetric studies of acrylamide-based copolymers with acrylic acid, [Poly(AM-co-AA)], and 2-acrylamido-2-methylpropane acid, [Poly(AM-co-NaAMPS)], suggest that the temperature induced swelling of the polymer beads and chains, create strongly entangled polymer networks, above the upper critical solution temperature. Analyses of the viscoelastic response showed that the time-scale for the gelation process is about minutes to hours. The addition of high concentrations of Ca2+ resulted in a significant decrease in the gel strength
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| 4. |
- Wilkins, Justin J., et al.
(författare)
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Variability in the population pharmacokinetics of pyrazinamide in South African tuberculosis patients
- 2006
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Ingår i: European Journal of Clinical Pharmacology. - : Springer Science and Business Media LLC. - 0031-6970 .- 1432-1041. ; 62:9, s. 727-735
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: This study was designed to characterize the population pharmacokinetics of pyrazinamide in South African pulmonary tuberculosis patients, with special reference to interindividual and interoccasional variability (IIV and IOV, respectively). METHODS: Concentration-time measurements obtained from 227 patients receiving oral doses of pyrazinamide were pooled to create a dataset containing 3,092 data points spanning multiple dosing occasions. The software program NONMEM was used to analyze the data. RESULTS: A one-compartment model with first-order absorption, including a zero-order component describing release from formulation, and first-order elimination best described the data. The absorption rate constant was estimated to be bimodally distributed between two distinct subgroups, fast and slow, in approximately even proportion. Absorption rate was threefold greater in fast absorbers (3.56 h(-1)) in comparison to slow absorbers (1.25 h(-1)). Typical values of oral clearance and apparent volume of distribution were estimated as 3.42 L h(-1) and 29.2 l, respectively. IOV was supported in oral clearance (0.0238, variance) and absorption rate (0.623, variance). The duration of zero-order absorption was estimated as 0.290 h, and was quite variable between patients (0.957, variance). CONCLUSION: The absorption of pyrazinamide in the studied population was highly variable and two separate subpopulations were identified. IOV accounted for a proportion of the variability in clearance and the absorption rate constant.
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