The partial oxidation of methane to methanol presents one of the most challenging targets in catalysis. Although this is the focus of much research, until recently, approaches had proceeded at low ...catalytic rates (<10 h−1), not resulted in a closed catalytic cycle, or were unable to produce methanol with a reasonable selectivity. Recent research has demonstrated, however, that a system composed of an iron‐ and copper‐containing zeolite is able to catalytically convert methane to methanol with turnover frequencies (TOFs) of over 14 000 h−1 by using H2O2 as terminal oxidant. However, the precise roles of the catalyst and the full mechanistic cycle remain unclear. We hereby report a systematic study of the kinetic parameters and mechanistic features of the process, and present a reaction network consisting of the activation of methane, the formation of an activated hydroperoxy species, and the by‐production of hydroxyl radicals. The catalytic system in question results in a low‐energy methane activation route, and allows selective C1‐oxidation to proceed under intrinsically mild reaction conditions.
Activate methane! A reaction network consisting of the activation of methane, the formation of an activated hydroperoxy species, and the by‐production of hydroxyl radicals is presented (see scheme). The catalytic system results in a low‐energy methane activation route, and allows selective C1‐oxidation to proceed under intrinsically mild reaction conditions.
Species determination based on genetic evidence is an indispensable tool in archaeology, forensics, ecology, and food authentication. Most available analytical approaches involve compromises with ...regard to the number of detectable species, high cost due to low throughput, or a labor-intensive manual process. Here, we introduce "Species by Proteome INvestigation" (SPIN), a shotgun proteomics workflow for analyzing archaeological bone capable of querying over 150 mammalian species by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Rapid peptide chromatography and data-independent acquisition (DIA) with throughput of 200 samples per day reduce expensive MS time, whereas streamlined sample preparation and automated data interpretation save labor costs. We confirm the successful classification of known reference bones, including domestic species and great apes, beyond the taxonomic resolution of the conventional peptide mass fingerprinting (PMF)-based Zooarchaeology by Mass Spectrometry (ZooMS) method. In a blinded study of degraded Iron-Age material from Scandinavia, SPIN produces reproducible results between replicates, which are consistent with morphological analysis. Finally, we demonstrate the high throughput capabilities of the method in a high-degradation context by analyzing more than two hundred Middle and Upper Palaeolithic bones from Southern European sites with late Neanderthal occupation. While this initial study is focused on modern and archaeological mammalian bone, SPIN will be open and expandable to other biological tissues and taxa.
•Biomarkers of smoke exposure (PAHs) were extremely high among Kenyan rural population.•Women who cooked indoors with wood without adequate ventilation were particularly affected.•This exposure was ...associated with the precursor lesion for esophageal cancer.•Community-based efforts to improve ventilation and cooking practices are needed.
Exposure to polycyclic aromatic hydrocarbons (PAHs) is a risk factor for esophageal squamous cell carcinoma (ESCC) in high-incidence areas of China, Iran and Brazil, but PAH assessments have not been conducted in East Africa, another ESCC hot spot.
To evaluate demographic or lifestyle factors associated with the PAH biomarker concentrations in the study population, and whether PAH metabolite concentrations showed any associations with esophageal precancerous lesions.
We recruited a community-based sample of 289 asymptomatic adults from a rural area of Kenya and performed Lugol’s chromoendoscopy to detect esophageal squamous dysplasia (ESD); participants completed a questionnaire and provided a spot urine specimen. We analyzed urine for seven hydroxylated metabolites of naphthalene, fluorene, phenanthrene, and pyrene at the U.S. National Center for Environmental Health, and compared creatinine-corrected PAH metabolite concentrations with questionnaire data and the presence of ESD.
PAH metabolite concentrations among never tobacco users in these rural Kenya residents were 2.4–28.1 times higher than those reported from never tobacco users in Iran, Brazil and the USA. Female sex, cooking indoors, having no post-primary education, and age <50, but not tobacco use, were positively and significantly associated with PAH metabolite concentrations. Almost all participants used wood as cooking fuel. Nine participants had advanced ESD. Adjusted logistic regression showed a significant association between 2-hydroxynaphthalene (OR = 4.19, 95%CI: 1.01–17.47) and advanced ESD. All other PAH metabolites had positive but non-significant associations with advanced ESD.
Urinary PAH metabolite concentrations among never tobacco users are markedly higher in this group from Kenya than in other populations and are associated with indoor cooking with wood on open, unvented stoves. These metabolite concentrations were also associated with the presence of advanced esophageal dysplasia. Our findings underline the importance of assessing alternative cooking conditions to reduce PAH exposure in this population.
All bound up: Au‐Pd nanoparticles having a mean particle size of 3–4 nm and supported on titania (see figure; scale bar 2 nm) exhibit high activity in the selective oxidation of aromatic hydrocarbons ...using tert‐butyl hydroperoxide as an oxidant. The supported nanoparticles stabilize surface‐bound radicals.
Objectives: We tested the hypothesis that social integration, measured as number of social roles, is associated with less age-related loss of lung function, an important marker of health and ...longevity. We also investigated possible psychological factors through which social integration might influence lung health. Methods: Data were analyzed from the Health and Retirement Study (ages 52-94, n = 4,224). Results and Conclusions: Each additional social role reported at baseline was associated with less of a decline in lung function between baseline and the follow-up assessment four years later. The association withstood controls for demographics, weight, and height and was mediated by more positive and less negative affect and lower rates of cigarette smoking and more physical activity. Roles were mostly substitutable, with both high (spouse, parent, friends, relatives) and low (employee, religious service attendee, volunteer, members of other groups) intimacy roles independently contributing to less age-related decline in lung function.
Histone H2AX promotes DNA double-strand break (DSB) repair and immunoglobulin heavy chain (IgH) class switch recombination (CSR) in B-lymphocytes. CSR requires activation-induced cytidine deaminase ...(AID) and involves joining of DSB intermediates by end joining. We find that AID-dependent IgH locus chromosome breaks occur at high frequency in primary H2AX-deficient B cells activated for CSR and that a substantial proportion of these breaks participate in chromosomal translocations. Moreover, activated B cells deficient for ATM, 53BP1, or MDC1, which interact with H2AX during the DSB response, show similarly increased IgH locus breaks and translocations. Thus, our findings implicate a general role for these factors in promoting end joining and thereby preventing DSBs from progressing into chromosomal breaks and translocations. As cellular p53 status does not markedly influence the frequency of such events, our results also have implications for how p53 and the DSB response machinery cooperate to suppress generation of lymphomas with oncogenic translocations.
...all known genetic predispositions will be available and, depending on the data sharing policy, accessible to a wide range of researchers and, possibly, the public at large--this, at a time when we ...are still seeking to understand the social, clinical, and personal implications of genetic information. More research and policy analysis on the issues associated with data release is clearly needed, including an analysis of the actual harms and benefits resulting from publicly accessible data; the implications for family members and relevant communities; the appropriate balance between public access and individual privacy interests; and considerations regarding compensation for research-related injury resulting from participation in personal genome research.
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