166 research outputs found
STUDIES ON SOLVENT EXTRACTION OF FREE HYDROGEN CYANIDE FROM RIVER WATER
A method for free and strongly complexed cyanide measurement in river water was developed. Recovery tests from solution with and without river water, using various solvent combinations and background control were investigated to obtain an accurate and precise extraction method for the measurement of hydrogen cyanide in Kaduna River, Nigeria. The method enhanced the determination of undissociated hydrogen cyanide and the equilibria between hydrogen cyanide, cyanide ion and complex cyanides. A small portion of the hydrogen cyanide was extracted by equilibrating the sample with methylchloroform (1,1,1-trichloroethane), methanol, hexane and 2-octanol inclusions, respectively, in the solvent matrix with 2.5 M NaOH. The extracted hydrogen cyanide is transferred into tetrasodium pyrophosphate solution and determined colorimetrically. A total cyanide concentration of 0.03 mg/L in the river water and 0.40 mg/L in an effluent water sample, respectively, were obtained by the proposed method compared to 0.020 and 0.45 mg/L from the established diffusion method. The proposed method was sensitive and reproducible in the range of 0 to 5 mgL-1 of hydrogen cyanide with detectable limit of about 0.01 mgL-1.
KEY WORDS: Solvent extraction; Free hydrogen cyanide; River water
Bull. Chem. Soc. Ethiop. 2007, 21(3), 305-313
Analysis of the Problems and Prospects in the Use of Local Building Materials: Review of Literature
One of the strong considerations for the use of Local Building Material (LBMs) in housing delivery is that it could reduce cost and enhance foreign exchange earnings. This paper examines the type of LBMs, problems envisaged in the use of LBMs, its prospects among other issues. This paper is essentially a review of literature from which inferences are drawn. Recommendations towards the use and acceptability of the LBMs include; (i) that various government agencies should engage in the use of LBMs rather than mere campaigning to developers (ii) that every state should establish cottage building industries to improve the supply, and that more researches should be engaged on for more discovery of LBMs
Criteria for the Extraction of Fish Oil
The effect of pre-treatment of mackery (Scomber scombrus) on oil recovery and quality was investigated. Fish oil was extracted using the screw expeller press after heat pre-treatment of the fish sample. The effect of cooking temperatures and cooking times was evaluated. It was observed that the oil yield has a positive relationship with cooking temperature. The oil yield increased with increasing cooking temperature at all the cooking times investigated and also increased with increasing cooking time from 5-15 minutes and then decreased for 20 minutes cooking time at all the cooking temperatures investigated. The results revealed that a highest yield of 22.8 % was obtained when the fish was treated at 90 0C cooking temperature for 15 minutes. The lowest oil yield of 16.5 % was obtained for the conditions of 60 0C cooking temperature and 5 minutes cooking time. Analysis of oil quality indices (e.g. colour, specific gravity, refractive index, free fatty acid value, saponification value. iodine value, peroxide value, unsaponifiable matter and microbiological analysis) of oil extracted by non pre-treatment and heat pre-treatment indicated that mackery oil from both processes has comparatively similar fatty acids composition. In addition, mackery fish oil was extracted by heat pre-treatment and mechanical press had lower lipid oxidation compared to several standards
Les Goitres Plongeants : Aspects Épidémiologiques, Cliniques, Radiologiques Et Thérapeutiques
Purpose: To describe the epidemiological and diagnostic aspects and surgical treatment procedures of plunging goiter in the Oto-Rhino- Laryngology and Neck Surgery Office of the National Hospital of Niamey in Niger. Materials and Methods: We analyzed the clinical and paraclinical symptoms as well as the technique and postoperative evolution of plunging goiters through a retrospective and descriptive study conducted from January 2010 to December 2015. Results: During the five years period, 15 cases of plunging goiter were registered representing 6.35% of thyroidectomy. Among the patients, there were 4 men (26.66%) and 11 women (73.34%). The mean age was 37.84 years. The character “plunging goiter” was noticed on clinical examination and confirmed by imaging. Two cases of hyperthyroidism were recorded. Eso-trachea compression that is characterized by dysphagia and dyspnea was recorded in 7 cases (46.66%), dysphonia in 2 cases (13.33%). The scanner performed in 8 cases showed a goiter with anterior superior mediastinal shift in 84.61%, driving the eso-tracheal axis in 62.5% of cases. The goiters plunged right in 5 cases (33.33%), left in 2 cases (13.33%) and were bilateral in 1 case. Complete thyroidectomy was performed on all patients by exclusive cervical way with as immediate complications, one intraoperative hemorrhage case (n = 1) and one transient hypoparathyroidism case (n = 1). Histological examination of surgical specimens shows no evidence of malignancy. Conclusion: The plunging goiters are rare and their treatment was complete thyroidectomy by exclusive cervical way. Postoperative evolution was uneventful
Surgical management of mesh-related complications after prior pelvic floor reconstructive surgery with mesh
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96379.pdf (publisher's version ) (Closed access)INTRODUCTION AND HYPOTHESIS: The objective of this study is to evaluate the complications and anatomical and functional outcomes of the surgical treatment of mesh-related complications. METHODS: A retrospective cohort study of patients who underwent complete or partial mesh excision to treat complications after prior mesh-augmented pelvic floor reconstructive surgery was conducted. RESULTS: Seventy-three patients underwent 30 complete and 51 partial mesh excisions. Intraoperative complications occurred in 4 cases, postoperative complications in 13. Symptom relief was achieved in 92% of patients. Recurrence of pelvic organ prolapse (POP) occurred in 29% of complete and 5% of partial excisions of mesh used in POP surgery. De novo stress urinary incontinence (SUI) occurred in 36% of patients who underwent excision of a suburethral sling. CONCLUSIONS: Mesh excision relieves mesh-related complications effectively, although with a substantial risk of serious complications and recurrence of POP or SUI. More complex excisions should be performed in skilled centers
Short Day–Mediated Cessation of Growth Requires the Downregulation of AINTEGUMENTALIKE1 Transcription Factor in Hybrid Aspen
Day length is a key environmental cue regulating the timing of major developmental transitions in plants. For example, in perennial plants such as the long-lived trees of the boreal forest, exposure to short days (SD) leads to the termination of meristem activity and bud set (referred to as growth cessation). The mechanism underlying SD–mediated induction of growth cessation is poorly understood. Here we show that the AIL1-AIL4 (AINTEGUMENTALIKE) transcription factors of the AP2 family are the downstream targets of the SD signal in the regulation of growth cessation response in hybrid aspen trees. AIL1 is expressed in the shoot apical meristem and leaf primordia, and exposure to SD signal downregulates AIL1 expression. Downregulation of AIL gene expression by SDs is altered in transgenic hybrid aspen plants that are defective in SD perception and/or response, e.g. PHYA or FT overexpressors. Importantly, SD–mediated regulation of growth cessation response is also affected by overexpression or downregulation of AIL gene expression. AIL1 protein can interact with the promoter of the key cell cycle genes, e.g. CYCD3.2, and downregulation of the expression of D-type cyclins after SD treatment is prevented by AIL1 overexpression. These data reveal that execution of SD–mediated growth cessation response requires the downregulation of AIL gene expression. Thus, while early acting components like PHYA and the CO/FT regulon are conserved in day-length regulation of flowering time and growth cessation between annual and perennial plants, signaling pathways downstream of SD perception diverge, with AIL transcription factors being novel targets of the CO/FT regulon connecting the perception of SD signal to the regulation of meristem activity
Maternal vaccination against COVID-19 and neonatal outcomes during Omicron: INTERCOVID-2022 study
Background: In early 2023, when Omicron was the variant of concern, we showed that vaccinating pregnant women decreased the risk for severe COVID-19-related complications and maternal morbidity and mortality. Objective: This study aimed to analyze the impact of COVID-19 during pregnancy on newborns and the effects of maternal COVID-19 vaccination on neonatal outcomes when Omicron was the variant of concern. Study design: INTERCOVID-2022 was a large, prospective, observational study, conducted in 40 hospitals across 18 countries, from November 27, 2021 (the day after the World Health Organization declared Omicron the variant of concern) to June 30, 2022, to assess the effect of COVID-19 in pregnancy on maternal and neonatal outcomes and to assess vaccine effectiveness. Women diagnosed with laboratory-confirmed COVID-19 during pregnancy were compared with 2 nondiagnosed, unmatched women recruited concomitantly and consecutively during pregnancy or at delivery. Mother-newborn dyads were followed until hospital discharge. The primary outcomes were a neonatal positive test for COVID-19, severe neonatal morbidity index, severe perinatal morbidity and mortality index, preterm birth, neonatal death, referral to neonatal intensive care unit, and diseases during the neonatal period. Vaccine effectiveness was estimated with adjustment for maternal risk profile. Results: We enrolled 4707 neonates born to 1577 (33.5%) mothers diagnosed with COVID-19 and 3130 (66.5%) nondiagnosed mothers. Among the diagnosed mothers, 642 (40.7%) were not vaccinated, 147 (9.3%) were partially vaccinated, 551 (34.9%) were completely vaccinated, and 237 (15.0%) also had a booster vaccine. Neonates of booster-vaccinated mothers had less than half (relative risk, 0.46; 95% confidence interval, 0.23-0.91) the risk of being diagnosed with COVID-19 when compared with those of unvaccinated mothers; they also had the lowest rates of preterm birth, medically indicated preterm birth, respiratory distress syndrome, and number of days in the neonatal intensive care unit. Newborns of unvaccinated mothers had double the risk for neonatal death (relative risk, 2.06; 95% confidence interval, 1.06-4.00) when compared with those of nondiagnosed mothers. Vaccination was not associated with any congenital malformations. Although all vaccines provided protection against neonatal test positivity, newborns of booster-vaccinated mothers had the highest vaccine effectiveness (64%; 95% confidence interval, 10%-86%). Vaccine effectiveness was not as high for messenger RNA vaccines only. Vaccine effectiveness against moderate or severe neonatal outcomes was much lower, namely 13% in the booster-vaccinated group (all vaccines) and 25% and 28% in the completely and booster-vaccinated groups, respectively (messenger RNA vaccines only). Vaccines were fairly effective in protecting neonates when given to pregnant women ≤100 days (14 weeks) before birth; thereafter, the risk increased and was much higher after 200 days (29 weeks). Finally, none of the neonatal practices studied, including skin-to-skin contact and direct breastfeeding, increased the risk for infecting newborns. Conclusion: When Omicron was the variant of concern, newborns of unvaccinated mothers had an increased risk for neonatal death. Neonates of vaccinated mothers had a decreased risk for preterm birth and adverse neonatal outcomes. Because the protective effect of COVID-19 vaccination decreases with time, to ensure that newborns are maximally protected against COVID-19, mothers should receive a vaccine or booster dose no more than 14 weeks before the expected date of delivery
Diabetes mellitus, maternal adiposity, and insulin-dependent gestational diabetes are associated with COVID-19 in pregnancy: the INTERCOVID study
BACKGROUND: Among nonpregnant individuals, diabetes mellitus and high body mass index increase the risk of COVID-19 and its severity.OBJECTIVE: This study aimed to determine whether diabetes mellitus and high body mass index are risk factors for COVID-19 in pregnancy and whether gestational diabetes mellitus is associated with COVID-19 diagnosis.STUDY DESIGN: INTERCOVID was a multinational study conducted between March 2020 and February 2021 in 43 institutions from 18 countries, enrolling 2184 pregnant women aged >= 18 years; a total of 2071 women were included in the analyses. For each woman diagnosed with COVID-19, 2 nondiagnosed women delivering or initiating antenatal care at the same institution were also enrolled. The main exposures were preexisting diabetes mellitus, high body mass index (overweight or obesity was defined as a body mass index >= 25 kg/m(2)), and gestational diabetes mellitus in pregnancy. The main outcome was a confirmed diagnosis of COVID-19 based on a real-time polymerase chain reaction test, antigen test, antibody test, radiological pulmonary findings, or >= 2 predefined COVID-19 symptoms at any time during pregnancy or delivery. Relationships of exposures and COVID-19 diagnosis were assessed using generalized linear models with a Poisson distribution and log link function, with robust standard errors to account for model misspecification. Furthermore, we conducted sensitivity analyses: (1) restricted to those with a real-time polymerase chain reaction test or an antigen test in the last week of pregnancy, (2) restricted to those with a real-time polymerase chain reaction test or an antigen test during the entire pregnancy, (3) generating values for missing data using multiple imputation, and (4) analyses controlling for month of enrollment. In addition, among women who were diagnosed with COVID-19, we examined whether having gestational diabetes mellitus, diabetes mellitus, or high body mass index increased the risk of having symptomatic vs asymptomatic COVID-19.RESULTS: COVID-19 was associated with preexisting diabetes mellitus (risk ratio, 1.94; 95% confidence interval, 1.55-2.42), overweight or obesity (risk ratio, 1.20; 95% confidence interval, 1.06-1.37), and gestational diabetes mellitus (risk ratio, 1.21; 95% confidence interval, 0.99-1.46). The gestational diabetes mellitus association was specifically among women requiring insulin, whether they were of normal weight (risk ratio, 1.79; 95% confidence interval, 1.06-3.01) or overweight or obese (risk ratio, 1.77; 95% confidence interval, 1.28-2.45). A somewhat stronger association with COVID-19 diagnosis was observed among women with preexisting diabetes mellitus, whether they were of normal weight (risk ratio, 1.93; 95% confidence interval, 1.18-3.17) or overweight or obese (risk ratio, 2.32; 95% confidence interval, 1.82-2.97). When the sample was restricted to those with a real-time polymerase chain reaction test or an antigen test in the week before delivery or during the entire pregnancy, including missing variables using imputation or controlling for month of enrollment, the observed associations were comparable.CONCLUSION: Diabetes mellitus and overweight or obesity were risk factors for COVID-19 diagnosis in pregnancy, and insulin-dependent gestational diabetes mellitus was associated with the disease. Therefore, it is essential that women with these comorbidities are vaccinated
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