Narrow range of early habitable Venus scenarios permitted by modeling of oxygen loss and radiogenic argon degassing.

Whether Venus was ever habitable is a key question driving missions to Earth's sister planet in the next decade. Venus today has a dry, O2-poor atmosphere, but recent work has proposed that early Venus may have had liquid water [J. Krissansen-Totton, J. J. Fortney, F. Nimmo, Planet. Sci. J. 2, 216 (2021)] and reflective clouds that could have sustained habitable conditions until 0.7 Ga [J. Yang, G. Boué, D. C. Fabrycky, D. S. Abbot, Astrophys. J. 787, L2 (2014), M. J. Way, A. D. Del Genio, J. Geophys. Res.: Planets 125, e2019JE006276 (2020)]. Water present at the end of a habitable era must since have been lost by photodissociation and H escape, causing buildup of atmospheric oxygen [F. Tian, Earth Planet. Sci. Lett. 432, 126-132 (2015)]. We present a time-dependent model of Venus's atmospheric composition starting from the end of a hypothetical habitable era with surface liquid water. We find that O2 loss to space, oxidation of reduced atmospheric species, oxidation of lava, and oxidation of a surface magma layer formed in a runaway greenhouse climate can remove O2 from up to 500 m global equivalent layer (GEL) (30% of an Earth ocean), unless melts on Venus had a much lower oxygen fugacity than Mid Ocean Ridge melts on Earth, which increases the upper limit twofold. Volcanism is required to supply oxidizable fresh basalt and reduced gases to the atmosphere but also contributes 40Ar. Consistency with Venus's modern atmospheric composition occurs in less than 0.4% of runs, in a narrow parameter range where the reducing power introduced by O2 loss processes can balance O2 introduced by H escape. Our models favor hypothetical habitable eras ending before 3 Ga and very reduced melt oxygen fugacities three log units below the fayalite-magnetite-quartz buffer (fO2< FMQ-3), among other constraints.

Methenamine hippurate compared with trimethoprim for the prevention of recurrent urinary tract infections: a randomized clinical trial.

INTRODUCTION AND HYPOTHESIS: The objective was to find an alternative treatment to a low-dose antibiotic for the prevention of recurrent urinary tract infections (UTI) and to evaluate the difference in rates of reinfection within 1 year when treated with methenamine hippurate for prophylaxis compared with trimethoprim. METHODS: We present a non-blinded randomized trial comparing methenamine hippurate with trimethoprim for the prevention of recurrent UTI at 12 months after starting treatment. Women over 18 who had at least two culture-positive UTI in the prior 6 months or three in the prior year were included. Ninety-two patients met enrollment criteria and were randomized to receive daily prophylaxis with methenamine hippurate or trimethoprim for a minimum of 6 months. Both intent-to-treat and per-protocol analyses if patients received the alternative drug after randomization were analyzed using Student's t test, Mann-Whitney U test, Kaplan-Meier curves, log-rank test, and a logistic and multivariate regression model. The primary outcome of this study was culture-proven UTI recurrence by 12 months after initiating prophylaxis. RESULTS: In the intent-to-treat analysis, we found no difference between groups in recurrent UTI, with a 65% (28 out of 43) recurrence in the trimethoprim group versus 65% (28 out of 43) in the methenamine hippurate group (p = 1.00). In the per-protocol analysis, 65% (26 out of 40) versus 65% (30 out of 46) of patients had UTI recurrences in the trimethoprim group versus the methenamine hippurate group (p = 0.98). CONCLUSIONS: Methenamine hippurate may be an alternative for the prevention of recurrent UTI, with similar rates of recurrence and adverse effects to trimethoprim.

Silylation of Pyridine, Picolines, and Quinoline with a Zinc Catalyst.

Zn(OTf)2 (OTf- = trifluoromethanesulfonate) catalyzes the silylation of pyridine, 3-picoline, and quinoline to afford the silylated products, where the silyl groups are meta to the nitrogen. The isolated yields of the products range from 41 to 26%. The 2- and 4-picolines yielded the silylmethylpyridines, where the CH3 groups were silylated instead of the ring. The pyridine silylation can occur via two separate pathways, involving either a 1,4- or a 1,2-hydrosilylation of pyridine as the first step. A byproduct of the pyridine silylation is a head-to-tail dimerization of N-silyl-1,4-dihydropyridine to form a diazaditwistane molecule.

Cognitive changes in women starting anticholinergic medications for overactive bladder: a prospective study.

INTRODUCTION AND HYPOTHESIS: To assess cognitive changes in women 12 months after starting anticholinergic medications for overactive bladder syndrome (OAB). METHODS: We present a prospective cohort study assessing changes in cognition in women seen in a referral urogynecology practice. We compared women who started anticholinergic OAB medications with women not on anticholinergic OAB medications. The primary outcome was change over time on the Montreal Cognitive Assessment (MOCA) screening score. At enrollment, women completed a baseline MOCA screening, a Geriatric Depression Screen (GDS), and an assessment of medications to create an anticholinergic burden score (ACB). At 3, 6, 9, and 12 months after enrollment women were administered the MOCA, GDS, and a review of their medications and medical problems. Statistical analysis was performed using a linear mixed effects model taking into account correlated error terms given multiple MOCA assessments at various time points per patient. RESULTS: A total of 106 women were enrolled, 60 in the OAB medication group and 46 in the control (non-OAB medication) group. The mean age was 77 years, 93% of women were Caucasian, and 98% completed high school, with no difference between groups. Over time there was no difference in change of MOCA score between the OAB and control groups when controlling for age, GDS score, and ACB score (p = 0.78). This association did not change when women with a neurological diagnosis were excluded (n = 6). On average MOCA scores for the OAB group increased by 0.76 over 12 months and the control group increased 0.39, with no difference between the groups (p = 0.53). CONCLUSIONS: We found no changes in MOCA scores between OAB medication and control groups after controlling for age, depression, and polypharmacy after 12 months of follow-up.

Equine sinonasal anaplastic sarcoma infected with multi-drug resistant Escherichia coli.

A 5-year-old Hanoverian horse was presented for a palpable and visible mass over the frontal and maxillary sinuses. Following endoscopy and radiography surgical excision was attempted. The horse was euthanized during surgery and samples of the mass were identified as malignant anaplastic sarcoma, a seldom reported sinonasal tumor in equids.

Sarcome anaplasique naso-sinusien équin infecté par Escherichia coli multirésistant aux antibiotiques. Un cheval Hanovrien âgé de 5 ans a été présenté pour une masse palpable et visible sur les sinus frontal et maxillaire. Après une endoscopie et la radiographie, une excision chirurgicale a été tentée. Le cheval a été euthanasié durant la chirurgie et des échantillons de la masse ont été identifiés comme un sarcome anaplasique malin, une tumeur naso-sinusienne rarement signalée chez les équidés.(Traduit par Isabelle Vallières).