Template-Directed Olefin Cross Metathesis

A template containing two secondary dialkylammonium ion recognition sites for encirclement by olefin-bearing dibenzo[24]crown-8 derivatives has been used to promote olefin cross metatheses with ruthenium-alkylidene catalysts. For monoolefin monomers, the rates of metatheses and yields of the dimers are both amplified in the presence of the template. Likewise, for a diolefin monomer, the yield of the dimer is enhanced in the presence of the template under conditions where higher oligomers are not formed

Localized Plasticity in the Streamlined Genomes of Vinyl Chloride Respiring Dehalococcoides

Vinyl chloride (VC) is a human carcinogen and widespread priority pollutant. Here we report the first, to our knowledge, complete genome sequences of microorganisms able to respire VC, Dehalococcoides sp. strains VS and BAV1. Notably, the respective VC reductase encoding genes, vcrAB and bvcAB, were found embedded in distinct genomic islands (GEIs) with different predicted integration sites, suggesting that these genes were acquired horizontally and independently by distinct mechanisms. A comparative analysis that included two previously sequenced Dehalococcoides genomes revealed a contextually conserved core that is interrupted by two high plasticity regions (HPRs) near the Ori. These HPRs contain the majority of GEIs and strain-specific genes identified in the four Dehalococcoides genomes, an elevated number of repeated elements including insertion sequences (IS), as well as 91 of 96 rdhAB, genes that putatively encode terminal reductases in organohalide respiration. Only three core rdhA orthologous groups were identified, and only one of these groups is supported by synteny. The low number of core rdhAB, contrasted with the high rdhAB numbers per genome (up to 36 in strain VS), as well as their colocalization with GEIs and other signatures for horizontal transfer, suggests that niche adaptation via organohalide respiration is a fundamental ecological strategy in Dehalococccoides. This adaptation has been exacted through multiple mechanisms of recombination that are mainly confined within HPRs of an otherwise remarkably stable, syntenic, streamlined genome among the smallest of any free-living microorganism

Development and Validation of a Risk Score for Chronic Kidney Disease in HIV Infection Using Prospective Cohort Data from the D:A:D Study

Ristola M. on työryhmien DAD Study Grp ; Royal Free Hosp Clin Cohort ; INSIGHT Study Grp ; SMART Study Grp ; ESPRIT Study Grp jäsen.Background Chronic kidney disease (CKD) is a major health issue for HIV-positive individuals, associated with increased morbidity and mortality. Development and implementation of a risk score model for CKD would allow comparison of the risks and benefits of adding potentially nephrotoxic antiretrovirals to a treatment regimen and would identify those at greatest risk of CKD. The aims of this study were to develop a simple, externally validated, and widely applicable long-term risk score model for CKD in HIV-positive individuals that can guide decision making in clinical practice. Methods and Findings A total of 17,954 HIV-positive individuals from the Data Collection on Adverse Events of Anti-HIV Drugs (D:A:D) study with >= 3 estimated glomerular filtration rate (eGFR) values after 1 January 2004 were included. Baseline was defined as the first eGFR > 60 ml/min/1.73 m2 after 1 January 2004; individuals with exposure to tenofovir, atazanavir, atazanavir/ritonavir, lopinavir/ritonavir, other boosted protease inhibitors before baseline were excluded. CKD was defined as confirmed (>3 mo apart) eGFR In the D:A:D study, 641 individuals developed CKD during 103,185 person-years of follow-up (PYFU; incidence 6.2/1,000 PYFU, 95% CI 5.7-6.7; median follow-up 6.1 y, range 0.3-9.1 y). Older age, intravenous drug use, hepatitis C coinfection, lower baseline eGFR, female gender, lower CD4 count nadir, hypertension, diabetes, and cardiovascular disease (CVD) predicted CKD. The adjusted incidence rate ratios of these nine categorical variables were scaled and summed to create the risk score. The median risk score at baseline was -2 (interquartile range -4 to 2). There was a 1: 393 chance of developing CKD in the next 5 y in the low risk group (risk score = 5, 505 events), respectively. Number needed to harm (NNTH) at 5 y when starting unboosted atazanavir or lopinavir/ritonavir among those with a low risk score was 1,702 (95% CI 1,166-3,367); NNTH was 202 (95% CI 159-278) and 21 (95% CI 19-23), respectively, for those with a medium and high risk score. NNTH was 739 (95% CI 506-1462), 88 (95% CI 69-121), and 9 (95% CI 8-10) for those with a low, medium, and high risk score, respectively, starting tenofovir, atazanavir/ritonavir, or another boosted protease inhibitor. The Royal Free Hospital Clinic Cohort included 2,548 individuals, of whom 94 individuals developed CKD (3.7%) during 18,376 PYFU (median follow-up 7.4 y, range 0.3-12.7 y). Of 2,013 individuals included from the SMART/ESPRIT control arms, 32 individuals developed CKD (1.6%) during 8,452 PYFU (median follow-up 4.1 y, range 0.6-8.1 y). External validation showed that the risk score predicted well in these cohorts. Limitations of this study included limited data on race and no information on proteinuria. Conclusions Both traditional and HIV-related risk factors were predictive of CKD. These factors were used to develop a risk score for CKD in HIV infection, externally validated, that has direct clinical relevance for patients and clinicians to weigh the benefits of certain antiretrovirals against the risk of CKD and to identify those at greatest risk of CKD.Peer reviewe

A Combined Experimental and Computational Study of Dihydrido-Phosphinooxazoline Iridium Complexes

The reaction of a [(PHOX)Ir(COD)]+ complex (COD = 1,5-cyclooctadiene) with dihydrogen was studied by NMR spectroscopy (PHOX = chiral phosphinooxazoline ligand). A single [(PHOX)Ir(H)2(COD)]+ isomer was formed as the primary product at -40 °C in THF. Subsequent reaction with H2 at -40 to 0 °C led to a mixture of two diastereomeric [(PHOX)Ir(H)2(solvent)2]+ complexes with concomitant loss of cyclooctane. The stereochemistry of the three hydride complexes could be assigned from the NMR data. The structures and energies of the observed hydride complexes and the possible stereoisomers were calculated using density functional theory. The substantial energy differences (up to 39 kcal/mol) between the various stereoisomers demonstrate the strong influence of the chiral ligand. The observed stereoselective formation of dihydride complexes can be explained by steric effects of the PHOX ligand combined with a strong electronic influence of the coordinating N and P atoms, favoring addition of a hydride trans to the Ir-N bond

The First Careers Fair Specifically for Chemists in Switzerland

Here we report on the first careers fair for chemists in Switzerland, contactchemists.ch. This event was organized by the Swiss Young Chemists' Committee Basel under the auspices of the SCS. Twelve companies accepted our invitation to take part and present their activities in both poster booths and oral presentations. This was complemented by a workshop that aided applicants in forming a suitable job-finding strategy. An informal exchange of information was possible and made contactchemists.ch a success not only for the participating companies but also for the numerous visitors. Synopses of the oral company presentations are included in this report

A multidomain lifestyle intervention to maintain optimal cognitive functioning in Dutch older adults—study design and baseline characteristics of the FINGER-NL randomized controlled trial

Abstract Background Evidence on the effectiveness of multidomain lifestyle interventions to prevent cognitive decline in older people without dementia is mixed. Embedded in the World-Wide FINGERS initiative, FINGER-NL aims to investigate the effectiveness of a 2-year multidomain lifestyle intervention on cognitive functioning in older Dutch at risk individuals. Methods Multi-center, randomized, controlled, multidomain lifestyle intervention trial with a duration of 24 months. 1210 adults between 60–79 years old with presence of ≥ 2 modifiable risk factors and ≥ 1 non-modifiable risk factor for cognitive decline were recruited between January 2022 and May 2023 via the Dutch Brain Research Registry and across five study sites in the Netherlands. Participants were randomized to either a high-intensity or a low-intensity intervention group. The multidomain intervention comprises a combination of 7 lifestyle components (physical activity, cognitive training, cardiovascular risk factor management, nutritional counseling, sleep counseling, stress management, and social activities) and 1 nutritional product (Souvenaid®) that could help maintain cognitive functioning. The high-intensity intervention group receives a personalized, supervised and hybrid intervention consisting of group meetings (on-site and online) and individual sessions guided by a trained lifestyle coach, and access to a digital intervention platform that provides custom-made training materials and selected lifestyle apps. The low-intensity intervention group receives bi-monthly online lifestyle-related health advice via the digital intervention platform. Primary outcome is 2-year change on a cognitive composite score covering processing speed, executive function, and memory. Results Within 17 months, participant recruitment has been successfully completed (N = 1210; mean age: 67.7 years (SD: 4.6); 64% female). Modifiable risk factors commonly present at baseline were physical inactivity (89%), low mental/cognitive activity (50%), low social engagement (39%), hypertension (39%) and high alcohol consumption (39%). The mean body mass index of participants was 28.3 (SD: 4.2) and the total serum cholesterol was 5.4 mmol/L (SD: 1.2). Conclusions Baseline lifestyle and clinical measurements showed successful recruitment of participants with sufficient potential for prevention. Results of FINGER-NL will provide further insight into the efficacy of a multidomain lifestyle intervention to prevent cognitive decline in older adults. Trial registration ClinicalTrials.gov (ID: NCT05256199)/2022–01-11