A general moment NRIXS approach to the determination of equilibrium Fe isotopic fractionation factors: application to goethite and jarosite

We measured the reduced partition function ratios for iron isotopes in goethite FeO(OH), potassium-jarosite KFe3(SO4)2(OH)6, and hydronium-jarosite (H3O)Fe3(SO4)2(OH)6, by Nuclear Resonant Inelastic X-Ray Scattering (NRIXS, also known as Nuclear Resonance Vibrational Spectroscopy -NRVS- or Nuclear Inelastic Scattering -NIS) at the Advanced Photon Source. These measurements were made on synthetic minerals enriched in 57Fe. A new method (i.e., the general moment approach) is presented to calculate {\beta}-factors from the moments of the NRIXS spectrum S(E). The first term in the moment expansion controls iron isotopic fractionation at high temperature and corresponds to the mean force constant of the iron bonds, a quantity that is readily measured and often reported in NRIXS studies.Comment: 38 pages, 2 tables, 8 figures. In press at Geochimica et Cosmochimica Acta. Appendix C contains new derivations relating the moments of the iron PDOS to the moments of the excitation probability function measured in Nuclear Resonant Inelastic X-ray Scatterin

The influence of the COVID-19 lockdown on infants' physiological regulation during mother-father-infant interactions in Switzerland.

In this study, we investigated the physiological regulation of vagal tone during dyadic and triadic parent-infant interactions in infants born before or around the COVID-19 lockdown in Switzerland. We hypothesized that there would be a decrease in vagal tone in triadic interactions compared with dyadic interactions, as triadic interactions are more complex and therefore more resource demanding. However, we expected this difference to be smaller for infants who experienced the period of confinement, as the lockdown led parents to spend more time at home. We also hypothesized that parents would have less stressful interactional events in the triadic interaction because they would be used to interacting with the child together. This study included 36 parents with their 3 month-old infants. Eighteen families met the study authors before the onset of the pandemic (pre-COVID) and 18 met them after its onset, having experienced a period of confinement during the infants' first 3 months of life (COVID). Results showed that the COVID group had no decrease in vagal tone during triadic interactions, whereas the pre-COVID group did. This difference could not, however, be explained by less stressful interactional events in triadic interactions, as the COVID group showed more stressful interactional events in mother-father-infant interactions

When gold stops glittering: corrosion mechanisms of René Lalique's Art Nouveau jewellery

ABSTRACT: Art Nouveau jewellery created by René Lalique is presently corroded. To identify the corrosion processes, Au-Ag-Cu alloys with compositions comparable to those used in the René Lalique’s jewellery were fabricated to be exposed to sulphide-containing environments. Using SEM-EDS, XRD, UV-Vis spectroscopy and ellipsometry, it was for the first time demon-strated that at the surface of tarnished Au alloys forms a corrosion film with a layer-by-layer structure. Considering the complex refractive indices of bulk Cu and Ag oxides and sulphides, a two-step corrosion mechanism was proposed. The formation of Cu-based compounds during the early corrosion stages is followed by the formation of Ag-based compounds. The thinness of the formed film, shown for one of the gold alloys to be of 80 nm, is due to a corrosion kinetics controlled by the presence of Au and by the formation of an Au-S self-assembled monolayer. The corrosion mechanism of gold alloys raises a new conservation challenge concerning the removal of nanometric layers.info:eu-repo/semantics/publishedVersio

HIV-Infektion : Update 2009 für Hausärzte. Teil 1

Quintessenz: In der Schweiz werden jährlich >750 HIV-Infektionen neu diagnostiziert. Die Ansteckung geschieht via Blut oder Sex, und nicht bei alltäglichen sozialen Kontakten. Die CD4-Lymphozytenzahl ist bestens etabliert zur Messung der Immunsuppression. Die grösste Gefahr opportunistischer Infekte droht bei CD4-Werten <200/μl. Dank antiretroviraler Therapie (ART) sollten viele HIV-infizierte Patienten in der Schweiz eine quasi normale Lebenserwartung haben. Momentan ist eine ART bei CD4-Werten <350/μl indiziert. Die HIV-Diagnose wird auch in der Schweiz häufig zu spät gestellt. Hausärzte spielen bei der frühzeitigen Diagnosestellung (grosszügiges Anbieten von HIV-Tests) und bei der Prävention von Immundefizienz und opportunistischen Komplikationen eine entscheidende Rolle. P Bei HIV-Neudiagnose soll der Patient einem HIV-Spezialisten zugewiesen werden, um weitere Abklärungen durchzuführen und die Indikation zum ART-Beginn zu stellen

Prediction of polyspecificity from antibody sequence data by machine learning

Antibodies are generated with great diversity in nature resulting in a set of molecules, each optimized to bind a specific target. Taking advantage of their diversity and specificity, antibodies make up for a large part of recently developed biologic drugs. For therapeutic use antibodies need to fulfill several criteria to be safe and efficient. Polyspecific antibodies can bind structurally unrelated molecules in addition to their main target, which can lead to side effects and decreased efficacy in a therapeutic setting, for example via reduction of effective drug levels. Therefore, we created a neural-network-based model to predict polyspecificity of antibodies using the heavy chain variable region sequence as input. We devised a strategy for enriching antibodies from an immunization campaign either for antigen-specific or polyspecific binding properties, followed by generation of a large sequencing data set for training and cross-validation of the model. We identified important physico-chemical features influencing polyspecificity by investigating the behaviour of this model. This work is a machine-learning-based approach to polyspecificity prediction and, besides increasing our understanding of polyspecificity, it might contribute to therapeutic antibody development

Oxygen isotopes and high ^(26)Mg excesses in a U-depleted fine-grained Allende CAI

CAIs are thought to be among the first solids formed in the early Solar System (ESS). As such, they are prime samples to study when (1) investigating ESS high-temperature processes, and (2) searching for evidence of short-lived radionu-clides at the time of formation of the SS. A recent systematic study of fine-grained CAIs characterized by a Group II REE pat-tern from Allende [1], found an extremely large ^(235)U excess (δ^(235)U >50 ‰ rel. to CRM-112a) in one sample: ME-3364 3.2. The discovery of this large ^(235)U excess provides definite evidence of the existence of live ^(247)Cm in the ESS, as previously suggested by [2]. In this study, we analyzed the oxygen isotope composi-tions and Al-Mg systematics of CAI ME-3364 3.2 to constrain the conditions of its formation

^(36)Cl-^(36)S in Allende CAIs: Implication for the origins of ^(36)Cl in the early solar system

Chlorine-36 (t_(1/2)=0.3 Myr) decays to either ^(36)Ar (98%, β-) or ^(36)S (1.9%, ε and β+). This radionuclide can be produced by either charged particle irradiation [1,2] or stellar nucleosynthesis [3]. Evidence for the prior existence of ^(36)Cl in the Early Solar System (ESS) comes from radiogenic excesses of ^(36)Ar [4,5] and/or ^(36)S [6-9] in secondary phases (e.g., sodalite and wadalite) of ESS materials such as Ca, Al-rich inclusions (CAIs) and chondrules. However, the inferred initial ^(36)Cl/^(35)Cl ratios vary over three orders of magnitude among different chondrite constituents (5×10^(-6)-9×10^(-3)) [6-9]. Interestingly, although the initial ^(36)Cl/^(35)Cl ratios inferred in previous studies vary widely, all secondary phases bearing evidence for live ^(36)Cl in the ESS measured so far lack resolvable ^(26)Mg excesses due to the decay of ^(26)Al (t_(1/2) = 0.7 Myr), implying that ^(36)Cl and ^(26)Al may have been produced by different processes and/or incorporated into ESS solids at different times. Given that secondary phases may have formed late, the ^(36)S anomalies in secondary phases point to either a very high ^(36)Cl/^(35)Cl initial ratio (~10^(-2)) in the ESS, or a late irradiation scenario for the local production of ^(36)Cl (> 3 Myr after CAI formation) [9]. The elevated ESS ratio of ^(36)Cl/^(35)Cl ~10^(-2) inferred from [9] far exceeds the predictions from any model of stellar nucleosynthesis; therefore, a late irradiation scenario producing ^(36)Cl is currently the favored idea. In this framework, ^(36)Cl would be be produced in the nebular gas and then incorporated into the CAIs via aqueous alteration, which formed secondary phases

Serial monitoring of pancreatic stone protein for the detection of sepsis in intensive care unit patients with complicated abdominal surgery: A prospective, longitudinal cohort study.

The objective of this study was to assess the performance of pancreatic stone protein (PSP) monitoring for the detection of sepsis, prediction of outcome and distinction between bacterial and fungal infections in intensive care unit (ICU) patients with complicated abdominal surgery. In this prospective multicenter cohort study, patients with complicated abdominal surgery had serial PSP measurements during their ICU stay. Infectious episodes were classified as bacterial, fungal or mixed. PSPmax (maximal PSP value within 48 h of the diagnosis of infection) and ΔPSP (difference between PSPmax and the preceding PSP value) were used for analyses. PSPmax was obtained for 118 infectious episodes (68 patients). ΔPSP was available for 73 episodes (48 patients). Both PSPmax and ΔPSP were significantly higher in patients with sepsis and in patients with a fatal outcome. A PSPmax ≥124 ng/ml and a ΔPSP ≥34 ng/ml could detect sepsis with a sensitivity/specificity of 84%/54% and 69%/76%, respectively. There was no significant difference of PSPmax or ΔPSP between patients with bacterial/mixed versus fungal infections. Serial PSP monitoring may be an additional tool for the early detection of sepsis in patients with complicated abdominal surgery who are at high risk of severe infections