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Chitosan (Ch) is a partially crystalline biopolymer, insoluble in pure water but soluble in acid solutions. It has attracted interest from researchers to prepare solutions using different acid types and concentrations. This research aims to study both the effect of chitosan (Ch) or acetic acid (Ac) concentrations, at different temperatures, on rheological and viscoelastic properties of Ch solutions. To study the effect of Ch, solutions were prepared with 0.5−2.5 g Ch/100 g of solution and Ac = 1%, whereas to study the effect of Ac, the solutions were prepared with 2.0 g of Ch/100 g of solution and Ac = 0.2−1.0%. Overall, all analyzed solutions behaved as pseudoplastic fluid. The Ch strongly affected rheological properties, the consistency index (K) increased and the index flow behavior (n) decreased as a function of Ch. The activation energy, defined as the energy required for the molecule of a fluid to move freely, was low for Ch = 0.5%. The effect of Ac was less evident. Both K and n varied according to a positive and negative, respectively, parabolic model as a function of Ac. Moreover, all solutions, irrespective of Ch and Ac, behaved as diluted solutions, with G" > G'. The relaxation exponent (n") was always higher than 0.5, confirming that these systems behaved as a viscoelastic liquid. This n" increased with Ch, but it was insensitive to Ac, being slightly higher at 45 °C.
RESUMO
Background: Pregnancy complications are the major health problems among women in developing countries. Globally, around 295,000 women die from pregnancy-related causes annually and 86% of these maternal deaths happen in developing countries. Objective: To assess knowledge of obstetric danger signs among reproductive-age women living in southeastern zone of Tigray Region, Ethiopia, 2021. Methods: A community-based quantitative cross-sectional survey was undertaken in southeastern zone of Tigray. A multistage random sampling technique was implemented to select total participants of 410 reproductive-age women. Two districts were randomly selected, and from those districts, 12 kebeles were selected randomly, and the calculated sample size (410) was proportionally allocated to each selected kebel. The data were collected by using face-to-face interview with a structured questionnaire from January 20 to February 20/2021 after ensuring that all requirements of ethical considerations were fulfilled. The collected data were entered into EpiData version 4.2 and then exported to SPSS version 20 for analysis. Descriptive statistics with frequency, percentage, table and graph, and cross-tabulation were used for presentation of result. Bivariable and multivariable analyses were used to examine the association. Odds ratios with 95% confidence interval and P value < 0.05 were used to determine the statistical association. Result: Four hundred ten reproductive-age women participated in the study making a response rate of 100%. Leakage of fluid per vagina was the most commonly mentioned obstetric danger signs (61%). Overall, one hundred seventy-two (42%) had good knowledge on obstetric danger sign. Educational status of the mother (AOR (95%CI = 2.7 (1.189-6.24))), site of delivery (AOR (95%CI = 2.2 (1.6-3.432))), and having history of an ANC follow-up (AOR (95%CI = 2.4 (1.13-5.6))) were found to be independent predictors of knowledge of women about the obstetric danger sign. Conclusion and Recommendation. Educational status of the mother site of delivery and having history of an ANC follow-up were independently associated with knowledge of women about obstetric danger signs. Thus, provision of the Information, Education and Communication targeting women, family, and the general community on obstetric danger signs and associated factors was recommended.
RESUMO
A study on speciation of chromium in soils near Sheba Leather Industry was performed by Flame Atomic Absorption (FAAS) after selective extraction of Cr(VI) using the EPA 3060A method, and oxidizing the Cr(III) residue in the soils with HNO3 and H2O2. The extraction method was evaluated using the spiking method with satisfactory results (recoveries>95% and RSDs<5%). The limit of detection (LOD) for Cr(VI) based on three times the standard deviations of the blank (for n=5) was 0.56 µg g(-1). Statistical evaluation indicated that the comparison of the sum of the concentrations of chromium species to that of the total concentration of chromium do not show any difference at 95% level of confidence. Besides, no statistically significant difference at 95% confidence level was observed between the UV-vis spectrophotometry and FAAS results for Cr(VI). However, it is observed that selective extraction of Cr(VI) using EPA 3060A and subsequent determination by FAAS is simple and faster compared to the other method. Furthermore, for comparison and as control two soil samples collected from a distance of about 2 km from the main Industry and effluent stream. The results indicate that higher total chromium content was observed in soils collected from the target area. Nevertheless, the maximum concentrations of Cr(VI) found in soil samples collected around Sheba Leather Industry was 9.9 µg g(-1) and are within the acceptable level of 10 µg g(-1) in accordance with the WHO.
