Removal of trace organics by MBR treatment: the role of molecular properties

This study examined the relationship between specific molecular features of trace organic contaminants and their removal efficiencies by a laboratory scale membrane bioreactor (MBR). Removal efficiencies of 40 trace organic compounds were assessed under stable operating conditions. The reported results demonstrate an apparent correlation between chemical structures and the removal of trace organic contaminants by the laboratory scale MBR system. The removal of all 14 very hydrophobic (Log D \u3e 3.2) trace organic compounds selected in this study was consistently high and was above 85%. The occurrence and types of electron withdrawing or donating functional groups appear to be important factors governing their removal by MBR treatment. In this study, all hydrophilic and moderately hydrophobic (Log D \u3c 3.2) compounds possessing strong electron withdrawing functional groups showed removal efficiency of less than 20%. In contrast, high removal efficiencies were observed with most compounds bearing electron donating functional groups such as hydroxyl and primary amine groups. A qualitative framework for the assessment of trace organic removal by MBR treatment was proposed to provide further insights into the removal mechanisms

Effects of thermal pre-treatment and recuperative thickening on the fate of trace organic contaminants during anaerobic digestion of sewage sludge

This study examined the effects of thermal pre-treatment and recuperative thickening on anaerobic digestion of sewage sludge on biogas production and removal of trace organic contaminants (TrOCs). Thermal pre-treatment and recuperative thickening resulted in approximately 15% increase in biogas production. However, the effects of thermal pretreatement and recuperative thickening on anaerobic digestion performance in respect to the removal of TrOCs were less obvious and varied widely depending on the molecular properties of each compound. Of the 40 TrOCs monitored in this study, 16 TrOCs were detected in all primary sludge samples. Removal from the aqueous phase was negligible for most of these 16 TrOCs. Caffeine and paracetamol were the only two TrOCs with a high removal from the aqueous phase. In comparison to the aqueous phase, TrOC removal from the solid phase was considerably higher. Through a mass balance calculation, it was shown that thermal pre-treatment or a combination of thermal pre-treatment and recuperative thickening could enhance the biodegradation of five persistent TrOCs, namely TCEP, verapamil, clozapine, triclosan, and triclocarban by 17-50%

Continuous transformation of chiral pharmaceuticals in enzymatic membrane bioreactors for advanced wastewater treatment

This study demonstrates continuous enantiomeric inversion and further biotransformation of chiral profens including ibuprofen, naproxen and ketoprofen by an enzymatic membrane bioreactor (EMBR) dosed with laccase. The EMBR showed non-enantioselective transformations, with high and consistent transformation of both (R)- and (S)-ibuprofen (93 ± 6%, n = 10), but lower removals of both enantiomers of naproxen (46 ± 16%, n = 10) and ketoprofen (48 ± 17%, n = 10). Enantiomeric analysis revealed a bidirectional but uneven inversion of the profens, for example 14% inversion of (R)- to (S)- compared to 4% from (S)- to (R)-naproxen. With redox-mediator addition, the enzymatic chiral inversion of both (R)- and (S)-profens remained unchanged, although the overall conversion became enantioselective; except for (S)-naproxen, the addition of redox mediator promoted the degradation of (R)-profens only

An anaerobic membrane bioreactor - membrane distillation hybrid system for energy recovery and water reuse: Removal performance of organic carbon, nutrients, and trace organic contaminants

In this study, a direct contact membrane distillation (MD) unit was integrated with an anaerobic membrane bioreactor (AnMBR) to simultaneously recover energy and produce high quality water for reuse from wastewater. Results show that AnMBR could produce 0.3-0.5 L/g CODadded biogas with a stable methane content of approximately 65%. By integrating MD with AnMBR, bulk organic matter and phosphate were almost completely removed. The removal of the 26 selected trace organic contaminants by AnMBR was compound specific, but the MD process could complement AnMBR removal, leading to an overall efficiency from 76% to complete removal by the integrated system. The results also show that, due to complete retention, organic matter (such as humic-like and protein-like substances) and inorganic salts accumulated in the MD feed solution and therefore resulted in significant fouling of the MD unit. As a result, the water flux of the MD process decreased continuously. Nevertheless, membrane pore wetting was not observed throughout the operation

Volumetric Properties of Binary Mixtures of 2-Ethoxyethanol and 2-Butoxyethanol with 1,4-Dioxane

Densities, r, of 2-Ethoxyethanol (EGMEE) + 1,4-Dioxane (DXN) and  2-Butoxyethanol (EGMBE) + 1,4-Dioxane (DXN) systems have been measured in the whole range of composition at an interval of 5 K ranging from 303.15 to 323.15 K. Excess molar volumes, , partial molar volumes, , thermal expansivities,a, and excess thermal expansivities, aE, have been estimated from the experimental values of ρ. All of the derived properties have been fitted to appropriate polynomials. Values of   and aE were fitted to the Redlich-Kister polynomial equation and their variations with composition and temperature have been discussed in terms of molecular interaction in the mixtures. Values of  and aE were all positive and were attributed due to specific interactions

Higher entropy observed in SARS-CoV-2 genomes from the first COVID-19 wave in Pakistan

Background: We investigated the genome diversity of SARS-CoV-2 associated with the early COVID-19 period to investigate evolution of the virus in Pakistan.Materials and methods: We studied ninety SARS-CoV-2 strains isolated between March and October 2020. Whole genome sequences from our laboratory and available genomes were used to investigate phylogeny, genetic variantion and mutation rates of SARS-CoV-2 strains in Pakistan. Site specific entropy analysis compared mutation rates between strains isolated before and after June 2020.Results: In March, strains belonging to L, S, V and GH clades were observed but by October, only L and GH strains were present. The highest diversity of clades was present in Sindh and Islamabad Capital Territory and the least in Punjab province. Initial introductions of SARS-CoV-2 GH (B.1.255, B.1) and S (A) clades were associated with overseas travelers. Additionally, GH (B.1.255, B.1, B.1.160, B.1.36), L (B, B.6, B.4), V (B.4) and S (A) clades were transmitted locally. SARS-CoV-2 genomes clustered with global strains except for ten which matched Pakistani isolates. RNA substitution rates were estimated at 5.86 x10-4. The most frequent mutations were 5\u27 UTR 241C \u3e T, Spike glycoprotein D614G, RNA dependent RNA polymerase (RdRp) P4715L and Orf3a Q57H. Strains up until June 2020 exhibited an overall higher mean and site-specific entropy as compared with sequences after June. Relative entropy was higher across GH as compared with GR and L clades. More sites were under selection pressure in GH strains but this was not significant for any particular site.Conclusions: The higher entropy and diversity observed in early pandemic as compared with later strains suggests increasing stability of the genomes in subsequent COVID-19 waves. This would likely lead to the selection of site-specific changes that are advantageous to the virus, as has been currently observed through the pandemic

The association between histamine 2 receptor antagonist use and Clostridium difficile infection: a systematic review and meta-analysis.

Background Clostridium difficile infection (CDI) is a major health problem. Epidemiological evidence suggests that there is an association between acid suppression therapy and development of CDI. Purpose We sought to systematically review the literature that examined the association between histamine 2 receptor antagonists (H2RAs) and CDI. Data source We searched Medline, Current Contents, Embase, ISI Web of Science and Elsevier Scopus from 1990 to 2012 for all analytical studies that examined the association between H2RAs and CDI. Study selection Two authors independently reviewed the studies for eligibility. Data extraction Data about studies characteristics, adjusted effect estimates and quality were extracted. Data synthesis Thirty-five observations from 33 eligible studies that included 201834 participants were analyzed. Studies were performed in 6 countries and nine of them were multicenter. Most studies did not specify the type or duration of H2RAs therapy. The pooled effect estimate was 1.44, 95% CI (1.22–1.7), I2 = 70.5%. This association was consistent across different subgroups (by study design and country) and there was no evidence of publication bias. The pooled effect estimate for high quality studies was 1.39 (1.15–1.68), I2 = 72.3%. Meta-regression analysis of 10 study-level variables did not identify sources of heterogeneity. In a speculative analysis, the number needed to harm (NNH) with H2RAs at 14 days after hospital admission in patients receiving antibiotics or not was 58, 95% CI (37, 115) and 425, 95% CI (267, 848), respectively. For the general population, the NNH at 1 year was 4549, 95% CI (2860, 9097). Conclusion In this rigorous systematic review and meta-analysis, we observed an association between H2RAs and CDI. The absolute risk of CDI associated with H2RAs is highest in hospitalized patients receiving antibiotics

Changes of DNA methylation are associated with changes in lung function during adolescence

Background Adolescence is a significant period for the gender-dependent development of lung function. Prior studies have shown that DNA methylation (DNA-M) is associated with lung function and DNA-M at some cytosine-phosphate-guanine dinucleotide sites (CpGs) changes over time. This study examined whether changes of DNA-M at lung-function-related CpGs are associated with changes in lung function during adolescence for each gender, and if so, the biological significance of the detected CpGs. Methods Genome-scale DNA-M was measured in peripheral blood samples at ages 10 (n = 330) and 18 years (n = 476) from the Isle of Wight (IOW) birth cohort in United Kingdom, using Illumina Infinium arrays (450 K and EPIC). Spirometry was conducted at both ages. A training and testing method was used to screen 402,714 CpGs for their potential associations with lung function. Linear regressions were applied to assess the association of changes in lung function with changes of DNA-M at those CpGs potentially related to lung function. Adolescence-related and personal and family-related confounders were included in the model. The analyses were stratified by gender. Multiple testing was adjusted by controlling false discovery rate of 0.05. Findings were further examined in two independent birth cohorts, the Avon Longitudinal Study of Children and Parents (ALSPAC) and the Children, Allergy, Milieu, Stockholm, Epidemiology (BAMSE) cohort. Pathway analyses were performed on genes to which the identified CpGs were mapped. Results For females, 42 CpGs showed statistically significant associations with change in FEV1/FVC, but none for change in FEV1 or FVC. No CpGs were identified for males. In replication analyses, 16 and 21 of the 42 CpGs showed the same direction of associations among the females in the ALSPAC and BAMSE cohorts, respectively, with 11 CpGs overlapping across all the three cohorts. Through pathway analyses, significant biological processes were identified that have previously been related to lung function development. Conclusions The detected 11 CpGs in all three cohorts have the potential to serve as the candidate epigenetic markers for changes in lung function during adolescence in female

The Association of Toll-Like Receptor 4 Polymorphism with Hepatitis C Virus Infection in Saudi Arabian Patients

Hepatitis C virus (HCV) is a single stranded RNA virus. It affects millions of people worldwide and is considered as a leading cause of liver diseases including cirrhosis and hepatocellular carcinoma. A recent study reported that TLR4 gene polymorphisms are good prognostic predictors and are associated with protection from liver fibrosis among Caucasians. This study aims to investigate the implication of genetic polymorphisms of TLR4 gene on the HCV infection in Saudi Arabian patients. Two SNPs in the TLR4 gene, rs4986790 (A/G) and rs4986791 (C/T), were genotyped in 450 HCV patients and 600 uninfected controls. The association analysis confirmed that both SNPs showed a significant difference in their distribution between HCV-infected patients and uninfected control subjects ( < 0.0001; OR = 0.404, 95% CI = 0.281-0.581) and ( < 0.0001; OR = 0.298, 95% CI = 0.201-0.443), respectively. More importantly, haplotype analysis revealed that four haplotypes, AC, GT, GC, and AT (rs4986790, rs4986791), were significantly associated with HCV infection when compared with control subjects. One haplotype AC was more prominently found when chronic HCV-infected patients were compared with cirrhosis/HCC patients (frequency = 94.7% and = 0.04). Both TLR4 SNPs under investigation were found to be significantly implicated with HCV-infection among Saudi Arabian population

Knowledge, perceptions and myths regarding infertility among selected adult population in Pakistan: a cross-sectional study

<p>Abstract</p> <p>Background</p> <p>The reported prevalence of infertility in Pakistan is approximately 22% with 4% primary and 18% secondary infertility. Infertility is not only a medical but also a social problem in our society as cultural customs and perceived religious dictums may equate infertility with failure on a personal, interpersonal, or social level. It is imperative that people have adequate knowledge about infertility so couples can seek timely medical care and misconceptions can be rectified.</p> <p>We aim to assess the knowledge, perception and myths regarding infertility and suggest ways to improve it.</p> <p>Methods</p> <p>A cross-sectional survey was carried out by interviewing a sample of 447 adults who were accompanying the patients at two tertiary care hospitals in Karachi, Pakistan. They were interviewed one-on-one with the help of a pretested questionnaire drafted by the team after a thorough literature review and in consultation with infertility specialists.</p> <p>Results</p> <p>The correct knowledge of infertility was found to be limited amongst the participants. Only 25% correctly identified when infertility is pathological and only 46% knew about the fertile period in women's cycle. People are misinformed that use of IUCD (53%) and OCPs (61%) may cause infertility. Beliefs in evil forces and supernatural powers as a cause of infertility are still prevalent especially amongst people with lower level of education. Seeking alternative treatment for infertility remains a popular option for 28% of the participant as a primary preference and 75% as a secondary preference. IVF remains an unfamiliar (78%) and an unacceptable option (55%).</p> <p>Conclusions</p> <p>Knowledge about infertility is limited in the population and a lot of misconceptions and myths are prevalent in the society. Alternative medicine is a popular option for seeking infertility treatment. The cultural and religious perspective about assisted reproductive technologies is unclear, which has resulted in its reduced acceptability.</p