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Supplemental material, sj-docx-1-jiv-10.1177_08862605221145720 for Longitudinal Associations Between Childhood Adversity and Adolescent Intimate Partner Violence in Malawi by Rachel Kidman, Etienne Breton, Jere R. Behrman, Andrew Zulu and Hans-Peter Kohler in Journal of Interpersonal Violence

Supplemental material, sj-docx-1-jiv-10.1177_08862605221145720 for Longitudinal Associations Between Childhood Adversity and Adolescent Intimate Partner Violence in Malawi by Rachel Kidman, Etienne Breton, Jere R. Behrman, Andrew Zulu and Hans-Peter Kohler in Journal of Interpersonal Violence

Supplemental material, sj-pdf-2-jiv-10.1177_08862605221145720 for Longitudinal Associations Between Childhood Adversity and Adolescent Intimate Partner Violence in Malawi by Rachel Kidman, Etienne Breton, Jere R. Behrman, Andrew Zulu and Hans-Peter Kohler in Journal of Interpersonal Violence

Supplemental material, sj-pdf-2-jiv-10.1177_08862605221145720 for Longitudinal Associations Between Childhood Adversity and Adolescent Intimate Partner Violence in Malawi by Rachel Kidman, Etienne Breton, Jere R. Behrman, Andrew Zulu and Hans-Peter Kohler in Journal of Interpersonal Violence

Oxygenations of aromatic soil and water contaminants with molecular O2catalyzed by Rieske dioxygenases are frequent initial steps of biodegradation in natural and engineered environments. Many of these non-heme ferrous iron enzymes are known to be involved in contaminant metabolism, but the understanding of enzyme-substrate interactions that lead to successful biodegradation is still elusive. Here, we studied the mechanisms of O2activation and substrate hydroxylation of two nitroarene dioxygenases to evaluate enzyme- and substrate-specific factors that determine the efficiency of oxygenated product formation. Experiments in enzyme assays of 2-nitrotoluene dioxygenase (2NTDO) and nitrobenzene dioxygenase (NBDO) with methyl-, fluoro-, chloro-, and hydroxy-substituted nitroaromatic substrates reveal that typically 20-100% of the enzyme's activity involves unproductive paths of O2activation with generation of reactive oxygen species through so-called O2uncoupling. The 18O and 13C kinetic isotope effects of O2activation and nitroaromatic substrate hydroxylation, respectively, suggest that O2uncoupling occurs after generation of FeIII-(hydro)peroxo species in the catalytic cycle. While 2NTDO hydroxylates ortho-substituted nitroaromatic substrates more efficiently, NBDO favors meta-substituted, presumably due to distinct active site residues of the two enzymes. Our data implies, however, that the O2uncoupling and hydroxylation activity cannot be assessed from simple structure-reactivity relationships. By quantifying O2uncoupling by Rieske dioxygenases, our work provides a mechanistic link between contaminant biodegradation, the generation of reactive oxygen species, and possible adaptation strategies of microorganisms to the exposure of new contaminants., ACS Environmental Au, 2 (5)

Rieske dioxygenases catalyze the initial steps in the hydroxylation of aromatic compounds and are critical for the metabolism of xenobiotic substances. Because substrates do not bind to the mononuclear non-heme FeII center, elementary steps leading to O2 activation and substrate hydroxylation are difficult to delineate, thus making it challenging to rationalize divergent observations on enzyme mechanisms, reactivity, and substrate specificity. Here, we show for nitrobenzene dioxygenase, a Rieske dioxygenase capable of transforming nitroarenes to nitrite and substituted catechols, that unproductive O2 activation with the release of the unreacted substrate and reactive oxygen species represents an important path in the catalytic cycle. Through correlation of O2 uncoupling for a series of substituted nitroaromatic compounds with 18O and 13C kinetic isotope effects of dissolved O2 and aromatic substrates, respectively, we show that O2 uncoupling occurs after the rate-limiting formation of FeIII-(hydro)peroxo species from which substrates are hydroxylated. Substituent effects on the extent of O2 uncoupling suggest that the positioning of the substrate in the active site rather than the susceptibility of the substrate for attack by electrophilic oxygen species is responsible for unproductive O2 uncoupling. The proposed catalytic cycle provides a mechanistic basis for assessing the very different efficiencies of substrate hydroxylation vs unproductive O2 activation and generation of reactive oxygen species in reactions catalyzed by Rieske dioxygenases., ACS Catalysis, 12 (11), ISSN:2155-5435

Using biodegradable instead of conventional plastics in agricultural applications promises to help overcome plastic pollution of agricultural soils. However, analytical limitations impede our understanding of plastic biodegradation in soils. Utilizing stable carbon isotope (13C-)labelled poly(butylene succinate) (PBS), a synthetic polyester, we herein present an analytical approach to continuously quantify PBS mineralization to 13CO2 during soil incubations and, thereafter, to determine non-mineralized PBS-derived 13C remaining in the soil. We demonstrate extensive PBS mineralization (65 % of added 13C) and a closed mass balance on PBS-13C over 425 days of incubation. Extraction of residual PBS from soils combined with kinetic modeling of the biodegradation data and results from monomer (i.e., butanediol and succinate) mineralization experiments suggest that PBS hydrolytic breakdown controlled the overall PBS biodegradation rate. Beyond PBS biodegradation in soil, the presented methodology is broadly applicable to investigate biodegradation of other biodegradable polymers in various receiving environments., Nature Communications, 13, ISSN:2041-1723

Additional file 1. Figure S1: Recruitment and enrolment of pregnant adolescents and women in a rural district in KwaZulu-Natal, South Africa between December 2016 to March 2017.

Supplemental Material for Marital Histories and Associations With Later-Life Dementia and Mild Cognitive Impairment Risk in the HUNT4 70+ Study in Norway by Vegard Skirbekk, Asta Håberg, Ekaterina Zotcheva, Bo Lars Engdahl, Steinar Krokstad, Hans-Peter Kohler, Astanand Jugessur, PhD, Bernt Bratsberg, Jordan Weiss, PhD, Catherine Bowen, Sarah Tom, PhD, Jennifer Harris, PhD, Yaakov Stern, PhD, Geir Selbæk, and Heine Strand, PhD in Journal of Aging and Health

We revisit the much-investigated relationship between schooling and health, focusing on cognitive abilities at older ages using the Harmonized Cognition Assessment Protocol in the Health & Retirement Study. To address endogeneity concerns, we employ a nonparametric partial identification approach that provides bounds on the population average treatment effect using a monotone instrumental variable together with relatively weak monotonicity assumptions on treatment selection and response. The bounds indicate potentially large effects of increasing schooling from primary to secondary but are also consistent with small and null effects. We find evidence for a causal effect of increasing schooling from secondary to tertiary on cognition. We also replicate findings from the Health & Retirement Study using another sample of older adults from the Midlife in United States Development Study Cognition Project.

Altres ajuts: Global Family Change (1729185) ; Juan de la Cierva (FJC2019-040652-I) ; Eunice Shriver Kennedy National Institute of Child Health and Human Development Population Research Infrastructure Program (NIH P2C HD044964) ; National Institute on Aging (NIH P30 AG012836) Studies on global changes in families have greatly increased over the past decade, adopting both a country-specific and, more recently, a cross-national comparative perspective. While most studies are focused on the drivers of global changes in families, little comparative research has explored the implications of family processes for the health and well-being of children. This study aims to fill this gap and launch a new research agenda exploring the intergenerational implications of union-formation and within-couple dynamics for children's health and well-being across low- and middle-income countries (LMICs), both globally, regionally, and by the stage of fertility transition. We do so by adopting a multi-axis conceptualization of children's outcomes - health at birth, health in later life, and schooling - and leveraging Demographic and Health Survey and World Bank data across 75 LMICs. Our results show that in settings where partnerships are characterized by more equal status between spouses - i.e., where the age range between spouses and differences in years of schooling between partners are narrower - their offspring fare better on several outcomes. These associations are particularly strong in mid- and highfertility settings. Despite a series of regularities, our results also highlight a set of findings whereby, at a macro-level, the prevalence of marriage and divorce/separation are not invariably associated with children's outcomes, especially in LMICs where fertility is comparatively lower. We document little crossregional heterogeneity, primarily highlighting the centrality of demographic factors such as age vis-à-vis, for instance, region-specific characteristics that are more tied to the social fabric of specific societies.

We provide new evidence on the effect of adolescent health behaviors/outcomes (obesity, depression, smoking, and attention deficit hyperactivity disorder (ADHD)) on schooling attainment using the National Longitudinal Study of Adolescent to Adult Health. We take two different approaches to deal with omitted variable bias and reverse causality. Our first approach attends to the issue of reverse causality by using health polygenic scores (PGSs) as proxies for actual adolescent health. Second, we estimate the effect of adolescent health using sibling fixed-effects models that control for unmeasured genetic and family factors shared by siblings. We use the PGSs as additional controls in the sibling fixed-effects models to reduce concerns about residual confounding from sibling-specific genetic differences. We find consistent evidence across both approaches that being genetically predisposed to smoking and smoking regularly in adolescence reduces schooling attainment. We find mixed evidence for ADHD. Our estimates suggest that having a high genetic risk for ADHD reduces grades of schooling, but we do not find any statistically significant negative effects of ADHD on grades of schooling. Finally, results from both approaches show no consistent evidence for a detrimental effect of obesity or depression on schooling attainment.

It is well-established that (1) there is a large genetic component to mental health, and (2) higher schooling attainment is associated with better mental health. Given these two observations, we test the hypothesis that schooling may attenuate the genetic predisposition to poor mental health. Specifically, we estimate associations between a polygenic score (PGS) for depressive symptoms, schooling attainment and gene-environment (GxE) interactions with mental health (depressive symptoms and depression), in two distinct United States datasets at different adult ages- 29 years old in the National Longitudinal Study of Adolescent Health (Add Health) and 54 years old in the Wisconsin Longitudinal Study (WLS). OLS results indicate that the association of the PGS with mental health is similar in Add Health and the WLS, but the association of schooling attainment is much larger in Add Health than in the WLS. There is some suggestive evidence that the association of the PGS with mental health is lower for more-schooled older individuals in the WLS, but there is no evidence of any significant GxE associations in Add Health. Quantile regression estimates also show that in the WLS the GxE associations are statistically significant only in the upper parts of the conditional depressive symptoms score distribution. We assess the robustness of the OLS results to omitted variable bias by using the siblings samples in both datasets to estimate sibling fixed-effect regressions. The sibling fixed-effect results must be qualified, in part due to low statistical power. However, the sibling fixed-effect estimates show that college education is associated with fewer depressive symptoms in both datasets.

This article provides a broad empirical overview of the relationship between family change and socioeconomic development drawing on 30-plus years of Demographic and Health Surveys data from 3.5 million respondents across 84 low- and middle-income countries (LMICs). We conduct two sets of analyses. First, we document global and regional-level associations between the Human Development Index (HDI) and novel indicators reflecting multi-dimensional family change. Second, we use methods from the growth convergence literature to examine whether—and in which domains—there is evidence of cross-country convergence in family indicators over levels of development. We show that families in LMICs have transformed in multiple ways, changing differently across domains, world regions, and genders. Fertility, intra-couple decision-making, and women’s life-course timing indicators are strongly associated with HDI, yet cross-country convergence is limited to the latter domain. Marriage, cohabitation, household structure, and men’s life-course timing indicators are more weakly associated with HDI, and span a broad spectrum of convergence dynamics ranging from divergence to modest convergence. We describe this scenario as “persistent diversity with development,” and shed light on the underlying regional heterogeneity—driven primarily by sub-Saharan Africa.

The extent to which physical functioning limitations result in permanent job loss, lowered lifetime income and assets, in part, depends upon the extent to which onset of these limitations becomes permanent. This paper uses five rounds of data from Malawi to examine path dependence in physical functioning limitations. We do so using a dynamic linear panel data model where the coefficient on the one-period lagged health outcome captures path dependence in functional limitations. Our preferred estimates indicate – (a) partial recovery from onset of functional limitations for males, (b) there is less recovery in severe limitations than moderate limitations for males, (c) perfect recovery from both moderate and severe functional limitation for females.

In high HIV-prevalence contexts, marriage can lead to significant risks through spousal behaviours. Yet, individuals cannot rely on their spouse to reveal their HIV status. Couples' HIV testing and counselling can provide spouses with credible information about each other's HIV status. Using random variation in participation in couples' testing, this study documents that uncertainty about spouses' HIV status contributes to marital dissolutions. Innovations, such as HIV couples' testing and counselling - and, in the future, possibly rapid self-testing - that reduce this uncertainty can thus have profound impacts on marital behaviours and stability.

Summary β‐Peptides and their derivates are usually stable to proteolysis and have an increased half‐life compared with α‐peptides. Recently, β‐aminopeptidases were described as a new enzyme class that enabled the enzymatic degradation and formation of β‐peptides. As an alternative to the existing chemical synthesis routes, the aim of the present work was to develop a whole‐cell biocatalyst for the synthesis and production of β‐peptides using this enzymatic activity. For the optimization of the reaction system we chose the commercially relevant β,α‐dipeptide l‐carnosine (β‐alanine‐l‐histidine) as model product. We were able to show that different recombinant yeast and bacteria strains, which overexpress a β‐peptidase, could be used directly as whole‐cell biocatalysts for the synthesis of l‐carnosine. By optimizing relevant reaction conditions for the best‐performing recombinant Escherichia coli strain, such as pH and substrate concentrations, we obtained high l‐carnosine yields of up to 71%. Long‐time as well as biocatalyst recycling experiments indicated a high stability of the developed biocatalyst for at least five repeated batches. Application of the recombinant E. coli in a fed‐batch process enabled the accumulation of l‐carnosine to a concentration of 3.7 g l−1.

For capturing dynamic demographic relationships, longitudinal household data can have considerable advantages over more widely used cross-sectional data. But because the collection of longitudinal data may be difficult and expensive, analysts must assess the magnitudes of the problems, specific to longitudinal, but not to cross-sectional data. One problem that concerns many analysts is that sample attrition may make the interpretation of estimates problematic. Such attrition may be especially severe where there is considerable migration between rural, and urban areas. And attrition is likely to be selective on such characteristics as schooling, so high attrition is likely to bias estimates. The authors consider the extent, and implications of attrition for three longitudinal household surveys from Bolivia, Kenya, and South Africa that report very high annual attrition rates between survey rounds. Their estimates indicate that: 1) the means for a number of critical outcome, and family background variables differ significantly between those who are lost to follow-up, and those who are re-interviewed. 2) A number of family background variables are significant predictors of attrition. 3) Nevertheless, the coefficient estimates for standard family background variables in regressions, and probit equations for the majority of outcome variables in all three data sets, are not significantly affected by attrition. So attrition is apparently not a general problem for obtaining consistent estimates of the coefficients of interest for most of these outcomes. These results, which are very similar to those for industrial countries, suggest that multivariate estimates of behavioral relations may not be biased because of attrition. This wold support the collection of longitudinal data.

Human leukocyte antigen (HLA) allele frequencies vary between different human populations, with implications both for the evolutionary pressures shaping those populations as well as for the outcome of new infectious epidemics. We defined HLA class I types in a well-described cohort of persons on Likoma Island in Malawi, a population for which there are lacking data on allelic frequencies. The profile of HLA frequencies was similar but phylogenetically distinct from those of other sub-Saharan African populations in neighboring regions. The most common A alleles included A30, A23, A28 (A*68), and A2, and the most common B alleles included B15 (group), B53, B58, and B44. Notably, the frequency of B53, which is protective against malaria, was similar to that of other malaria-endemic African countries, and higher than that in countries with less malaria. This is the first reported significant dataset of HLA class I allelic frequencies in Malawians.

The extent and structure of sexual networks have important consequences for the spread of sexually transmitted diseases such as HIV. However, very few datasets currently exist that allow a detailed investigation of sexual networks in sub-Saharan African settings where HIV epidemics have become generalized. In this paper, we describe the context and methods of the Likoma Network Study (LNS), one of the few studies that have collected extensive information on sexual networks in sub-Saharan Africa. We start by reviewing theoretical arguments and empirical studies emphasizing the importance of network structures in the epidemiology of HIV and other sexually transmitted infections (STI). The island setting of this study is described, and we argue that the choice of an island as a research site limited potential biases that may make the collection of sexual network data difficult. We then document our empirical strategy for the collection of sexual network data and the subsequent identification of sexual network partners. A description of the protocol for the collection of biomarker data (HIV infection) is provided. Finally, we present initial results relating to the socioeconomic context of the island, the size and composition of sexual networks, the quality of the sexual network data, the determinants of successful contact tracing during the LNS, and the prevalence of HIV in the study population.

Objective: To examine the acceptance of repeat population-based voluntary counseling and testing (VCT) for HIV in rural Malawi. Methods: Behavioral and biomarker data were collected in 2004 and 2006 from approximately 3,000 adult respondents. In 2004, oral swab specimens were collected and analyzed using enzyme-linked immunosorbent assay (ELISA) and confirmatory Western blot tests while finger-prick rapid testing was done in 2006. We use cross-tabulations with chi-square tests and significance tests of proportions to determine the statistical significance of differences in acceptance of VCT by year, individual characteristics and HIV risk. Results: First, over 90% of respondents in each round accepted HIV test, despite variations in testing protocols. Second, the percentage of individuals who obtained their test results significantly increased from 67% in 2004 when the results were provided in randomly selected locations several weeks after the specimens were collected, to 98% in 2006 when they were made available immediately within the home. Third, whereas there were significant variations in the socio-demographic and behavioral profiles of those who were successfully contacted for a second HIV test, this was not the case for those who accepted repeat VCT. This suggests that variations in the success of repeat testing might come from contacting the individuals rather than from accepting the test or knowing the results. Conclusions: Repeat HIV testing at home by trained health care workers from outside the local area, and with either saliva or blood, is almost universally acceptable in rural Malawi, and thus likely to be acceptable in similar contexts.

Network-based strategies and competencies are probably even more important in poor societies with limited means of communication and less effective formal structures than in developed economies. And they often deal with life and death matters. This paper presents lessons from and insights about the nature of and the impacts of informal social networks in reducing fertility and coping with HIV/AIDS in Kenya and Malawi based on analyses of quantitative longitudinal data and qualitative data that the authors and their collaborators have been collecting and analyzing for over a decade. Specific lessons include the relevance of social networks and informal interactions for many different domains related to health – and thus life and death – in developing countries, the importance of accounting for the endogeneity of network partners in analyzing network effects, that networks are important even with control for endogeneity, that network effects may be nonlinear, that there may be multiple equilibria, that which networks may either reinforce the status quo or help diffuse new options and behaviors, that both the context (e.g., the degree of market development) and the density of networks matter (possibly interactively), and that multiple approaches, including both qualitative and quantitative analyses, can be informative in providing more in-depth understanding of what networks do and how they function.

"Eine ausgeprägte Präferenz für männliche Nachkommen, mit zum Teil dramatischen Folgen für die Lebenssituation von Mädchen und Frauen, findet sich heute vor allem in einer Reihe asiatischer Länder, wie China, Indien oder Korea. Geschlechterpräferenzen für Kinder sind jedoch ein kulturelles und demographisches Phänomen, das auch in modernen westlichen Gesellschaften zunehmend beachtet wird. In den vergangenen Jahrzehnten sind nicht nur traditionelle Geschlechterrollen teilweise erodiert, sondern auch die Geburtenneigung ist deutlich zurückgegangen. Darüber hinaus erlauben es neue Verfahren der Reproduktionsmedizin (z.B. MicroSort), das Geschlecht eines Kindes vorzubestimmen. Wie hat sich vor diesem Hintergrund der spezifische Wunsch von Paaren nach einem Sohn oder nach einer Tochter verändert? Gibt es in Europa überhaupt (noch) Geschlechterpräferenzen, und falls ja: sind sie regional und über die Zeit stabil, oder lassen sich möglicherweise unterschiedliche Entwicklungen beobachten? Die Verfasser untersuchen die Existenz von Geschlechterpräferenzen und ihren Effekt auf Fertilitätsentscheidungen in Deutschland (auf Basis von Daten des ALLBUS 2000) sowie in Dänemark, Finnland, Norwegen und Schweden (unter Verwendung der jeweiligen Bevölkerungsregister seit 1961/71). Dabei zeigt sich, dass a) in allen Ländern verhaltensrelevante Geschlechterpräferenzen für Kinder existieren, b) dass es diesbezüglich - mutmaßlich kulturell bedingte - regionale Unterschiede gibt, und c) dass sich sogar 'neue' Präferenzen parallel zu gesellschaftlichen Modernisierungsprozessen entwickeln können." (Autorenreferat)

Longitudinal household data can have considerable advantages over much more widely used cross-sectional data. The collection of longitudinal data, however, may be difficult and expensive. One problem that has concerned many analysts is that sample attrition may make the interpretation of estimates problematic. Such attrition may be particularly severe in areas where there is considerable mobility because of migration between rural and urban areas. Many analysts share the intuition that attrition is likely to be selective on characteristics such as schooling and that high attrition is likely to bias estimates made from longitudinal data. This paper considers the extent of and implications of attrition for three longitudinal household surveys from Bolivia, Kenya, and South Africa that report very high per-year attrition rates between survey rounds. Our estimates indicate that (1) the means for a number of critical outcome and family background variables differ significantly between attritors and nonattritors; (2) a number of family background variables are significant predictors of attrition; but (3) nevertheless, the coefficient estimates for “standard” family background variables in regressions and probit equations for the majority of the outcome variables considered in all three data sets are not affected significantly by attrition. Therefore, attrition apparently is not a general problem for obtaining consistent estimates of the coefficients of interest for most of these outcomes. These results, which are very similar to results for developed economies, suggest that for these outcome variables—despite suggestions of systematic attrition from univariate comparisons between attritors and nonattritors, multivariate estimates of behavioral relations of interest may not be biased due to attrition.

To cite this article: Schroeder V, Kohler HP. New developments in the area of factor XIII. J Thromb Haemost 2013; 11: 234-44. Summary. Coagulation factor (F)XIII is best known for its role in fibrin stabilization and cross-linking of antifibrinolytic proteins to the fibrin clot. From patients with congenital FXIII deficiency, it is known that FXIII also has important functions in wound healing and maintaining pregnancy. Over the last decade more and more research groups with different backgrounds have studied FXIII and have unveiled putative novel functions for FXIII. FXIII, with its unique role as a transglutaminase among the other serine protease coagulation factors, is now recognized as a multifunctional protein involved in regulatory mechanisms and construction and repair processes beyond hemostasis with possible implications in many areas of medicine. The aim of this review was to give an overview of exciting novel findings and to highlight the remarkable diversity of functions attributed to FXIII. Of course, more research into the underlying mechanisms and (patho-)physiological relevance of the many described functions of FXIII is needed. It will be exciting to observe future developments in this area and to see if and how these interesting findings may be translated into clinical practice in the future.

Although the production and use of technical hexachlorocyclohexane (HCH) and lindane (the purified insecticidal isomer -HCH) are prohibited in most countries, residual concentrations still constitute an immense environmental burden. Many studies describe the mineralization of -HCH by bacterial strains under aerobic conditions. However, the metabolic fate of the other HCH isomers is not well known. In this study, we investigated the transformation of -, -, -, -, epsilon-HCH, and a heptachlorocyclohexane isomer in the presence of varying ratios of the two enzymes that initiate -HCH degradation, a dehydrochlorinase (LinA) and a haloalkane dehalogenase (LinB). Each substrate yielded a unique metabolic profile that was strongly dependent on the enzyme ratio. Comparison of these results to those of in vivo experiments with different bacterial isolates showed that HCH transformation in the tested strains was highly optimized towards productive metabolism of -HCH and that under these conditions other HCH-isomers were metabolized to mixtures of dehydrochlorinated and hydroxylated side-products. In view of these results, bioremediation efforts need very careful planning and toxicities of accumulating metabolites need to be evaluated.

Plastic materials are widely used in agricultural applications to achieve food security for the growing world population. The use of biodegradable instead of nonbiodegradable polymers in single-use agricultural applications, including plastic mulching, promises to reduce plastic accumulation in the environment. We present a novel approach that allows tracking of carbon from biodegradable polymers into CO2 and microbial biomass. The approach is based on 13C-labeled polymers and on isotope-specific analytical methods, including nanoscale secondary ion mass spectrometry (NanoSIMS). Our results unequivocally demonstrate the biodegradability of poly(butylene adipate-co-terephthalate) (PBAT), an important polyester used in agriculture, in soil. Carbon from each monomer unit of PBAT was used by soil microorganisms, including filamentous fungi, to gain energy and to form biomass. This work advances both our conceptual understanding of polymer biodegradation and the methodological capabilities to assess this process in natural and engineered environments., Science Advances, 4 (7), ISSN:2375-2548

delta-Hexachlorocyclohexane (delta-HCH), one of the prevalent isomers of technical HCH, was enantioselectively dehydrochlorinated by the dehydrochlorinases LinA1 and LinA2 from Sphingobium indicum B90A to the very same delta-pentachlorocyclohexene enantiomer. Racemic delta-pentachlorocyclohexene, however, was transformed with opposite enantioselectivities by the two enzymes. A transformation pathway based on an anti-1,2-elimination, followed by a syn-1,4-elimination and a subsequent syn-1,2-elimination is postulated.

Reactions of ozone (O-3) with the beta-lactam antibiotics penicillin G (PG) and cephalexin (CP) have previously been found to yield products retaining antibacterial activities. These products are unequivocally identified here as the stereoisomeric (R)-sulfoxides of each parent molecule and characterized by a combination of chemical analysis and an antibacterial activity assay. PG-(R)-sulfoxide, which is similar to 15% as potent as PG itself, is formed in similar to 55% yield, whereas CP-(R)-sulfoxide, which is similar to 83% as active as CP, is formed with a maximum similar to 34% yield. PG-(R)-sulfoxide is recalcitrant toward further oxidation by O-3, but readily transformed by hydroxyl radical (HO center dot) k(HO center dot)(,app)(N) = 7.4 x 10(9) M(-1)s(-1), pH 7), resulting in quantitative elimination of its antibacterial activity. In contrast CP-(R)-sulfoxide is degraded by both O-3 and HO center dot (k"(O3,app) = 2.6 x 10(4) M-1 s(-1) and k"(HO center dot,app) = 7.6 x 10(9) M-1 s(-1), pH 7), leading to quantitative elimination of its antibacterial activity. During ozonation of a secondary municipal wastewater effluent sample (pH 8.1, C-DOC = 4.0 mg/L, [alkalinity] = 3.6 mM as HCO3-) spiked with [PG](0) = 1 mu M, PG-(R)-sulfoxide yields did not exceed 0.15 mu M for O-3 doses up to 100 mu M (4.8 mg/L), but reached 0.47 mu M with 10-mM t-BuOH added as a HO center dot scavenger. In contrast, CP-(R)-sulfoxide yields did not exceed 0.1 mu M for the same wastewater spiked with [CP](0) = 1,mu M in either the presence or absence of t-BuOH, indicating that CP-(R)-sulfoxide transformation is governed primarily by direct reaction with O-3. These findings suggest that, for a given degree of parent compound transformation, PG-(R)-sulfoxide yields would likely be greatest during zonation of wastewaters characterized by low O-3 demands and high HO center dot scavenging rates, whereas CP-(R)-sulfoxide yields would be less matrix-dependent In general, complete deactivation of penicillins during wastewater treatment will likely require higher O-3 exposures than necessary for deactivation of cephalosporins.

Most peri-alpine shallow aquifers fed by rivers are oxic and the drinking water derived by riverbank filtration is generally of excellent quality. However, observations during past heat waves suggest that water quality may be affected by climate change due to effects on redox processes such as aerobic respiration, denitrification, reductive dissolution of manganese(III/IV)- and iron(III)(hydr)oxides that occur during river infiltration. To assess the dependence of these redox processes on the climate-related variables temperature and discharge, we performed periodic and targeted (summer and winter) field sampling campaigns at the Thur River, Switzerland, and laboratory column experiments simulating the field conditions. Typical summer and winter field conditions could be successfully simulated by the column experiments. Dissolved organic matter (DOM) was found not to be a major electron donor for aerobic respiration in summer and the DOM consumption did not reveal a significant correlation with temperature and discharge. It is hypothesized that under summer conditions, organic matter associated with the aquifer material (particulate organic matter, POM) is responsible for most of the consumption of dissolved oxygen (DO), which was the most important electron acceptor in both the field and the column system. For typical summer conditions at temperatures >20 °C, complete depletion of DO was observed in the column system and in a piezometer located only a few metres from the river. Both in the field system and the column experiments, nitrate acted as a redox buffer preventing the release of manganese(II) and iron(II). For periodic field observations over five years, DO consumption showed a pronounced temperature dependence (correlation coefficient r = 0.74) and therefore a seasonal pattern, which seemed to be mostly explained by the temperature dependence of the calculated POM consumption (r = 0.7). The river discharge was found to be highly and positively correlated with DO consumption (r = 0.85), suggesting an enhanced POM input during flood events. This high correlation could only be observed for the low-temperature range (T < 15 °C). For temperatures >15 °C, DO consumption was already high (almost complete) and the impact of discharge could not be resolved. Based on our results, we estimate the risk for similar river-infiltration systems to release manganese(II) and iron(II) to be low during future average summer conditions. However, long-lasting heat waves might lead to a consumption of the nitrate buffer, inducing a mobilization of manganese and iron.

Riverbank filtration is an established technique used world-wide to produce clean drinking water in a reliable and cost-efficient way. This practice is, however, facing new challenges posed by climate change, as already observed during past heat waves with the local occurrence of anoxic conditions. In this study we investigated the effect of direct (temperature) and indirect (dissolved organic matter (DOM) concentration and composition, flow rate) climate change variables on redox processes (aerobic respiration, denitrification and Mn(III/IV)/Fe(III) reduction) by means of column experiments. Natural river water, modified river water and river water mixed with treated wastewater effluent were used as feed waters for the columns filled with natural sand from a river-infiltration system in Switzerland. Biodegradable dissolved organic matter was mainly removed immediately at the column inlet and particulate organic matter (POM) associated with the natural sand was the main electron donor for aerobic respiration throughout the column. Low infiltration rates (

Scientific reports 7, 15783 (2017). doi:10.1038/s41598-017-16132-8, Published by Nature Publishing Group, London

Soil biodegradable mulch films composed of the polyester polybutylene adipate-co-terephthalate (PBAT) are being increasingly used in agriculture. Analytical methods to quantify PBAT in field soils are needed to assess its soil occurrence and fate. Here, we report an analytical method for PBAT in soils that couples Soxhlet extraction or accelerated solvent extraction (ASE) with quantitative protonnuclear magnetic resonance (q-H-1 NMR) spectroscopy detection. The H-1 NMR peak areas of aromatic PBAT protons increased linearly with PBAT concentrations dissolved in deuterated chloroform (CDCl3), demonstrating accurate quantitation of PBAT by q-H-1 NMR Spike-recovery experiments involving PBAT addition to model sorbents and soils showed increased PBAT extraction efficiencies into chloroform (CHCl3) with methanol (MeOH) as cosolvent, consistent with MeOH competitively displacing PBAT from H-bond donating sites on mineral surfaces. Systematic variations in solvent composition and temperatures in ASE revealed quantitative PBAT extraction from soil with 90/10 volume % CHCl3/MeOH at 110-120 degrees C. Both Soxhlet extraction and ASE resulted in the complete recovery of PBAT added to a total of seven agricultural soils covering a range of physicochemical properties, independent of whether PBAT was added to soils dissolved in CHCl3, as film, or as particles. Recovery was also complete for PBAT added to soil in the form of a commercial soil biodegradable mulch film with coextractable polylactic acid (PLA). The presented analytical method enables accurate quantification and biodegradation monitoring of PBAT in agricultural field soils.