Siliconoid Expansion by a Single Germanium Atom through Isolated Intermediates

The growth of (semi-)metal clusters is pivotal for nucleation processes in gaseous and condensed phases. We now report the isolation of intermediates during the expansion of a stable unsaturated silicon cluster (siliconoid) by a single germanium atom through a sequence of substitution, rearrangement and reduction. The reaction of ligato-lithiated hexasilabenzpolarene LiSi6Tip5 (1Li⋅(thf)2, Tip=2,4,6-triisopropylphenyl) with GeCl2⋅NHC (NHC=1,3-diisopropyl-4,5-dimethylimidazol-2-ylidene) initially yields the product with exohedral germanium(II) functionality, which then inserts into an Si−Si bond of the Si6 scaffold. The concomitant transfer of the chloro functionality from germanium to an adjacent silicon preserves the electron-precise nature of the formed endohedral germylene. Full incorporation of the germanium heteroatom to the Si6Ge cluster core is finally achieved either by reduction under loss of the coordinating NHC or directly by reaction of 1Li⋅(thf)2 with GeCl2⋅1,4-dioxane

Interlinkage of a siliconoid with a silsesquioxane : en route to a molecular model system for silicon monoxide

A new potential model system for silicon monoxide (SiO) is synthesized by the interlinkage of an unsaturated silicon cluster (siliconoid) with a polyhedral silsequioxane cage. Two derivatives with variable linker size are obtained by the corner-capping reaction of Ph7T7(ONa)3 with a trichlorosilane featuring a remote benzylic chloride functionality and the subsequent nucleophilic substitution of the latter by the anionic hexasilabenzpolarene-type Si6 siliconoid. Based on the recently proposed heterogeneous cluster model for the SiO structure, the stoichiometry between silicon and oxygen reiterates the suboxidic interface of the nano-composite in a Si : O ratio of 14 : 12

Gerüsterweiterung eines Silicoids um ein einzelnes Germaniumatom über isolierte Zwischenprodukte

Das Wachstum von (Halb-)Metallclustern ist entscheidend für Keimbildungsprozesse in gasförmigen und kondensierten Phasen. Wir berichten nun über die Isolierung von Zwischenprodukten während der Erweiterung eines stabilen, ungesättigten Siliciumclusters (Silicoid) um ein einzelnes Germaniumatom durch eine Abfolge von Substitution, Umlagerung und Reduktion. Die Reaktion von ligato-lithiiertem Hexasilabenzpolaren LiSi6Tip5 (Li·(thf)2, Tip=2,4,6-Triisopropylphenyl) mit GeCl2·NHC (NHC=1,3-Diisopropyl-4,5-dimethylimidazol-2-yliden) liefert zunächst das Produkt mit exohedraler Germanium(II)-Funktionalität, die dann in eine Si Si Bindung des Si6-Gerüsts insertiert. Die gleichzeitige Übertragung der Chlorfunktionalität von Germanium auf ein benachbartes Siliciumatom bewahrt die elektronenpräzise Natur des gebildeten endohedralen Germylens. Der vollständige Einbau des Germaniumheteroatoms in den Si6Ge-Clusterkern wird schließlich entweder durch Reduktion unter Verlust des koordinierenden NHC oder direkt durch Reaktion von 1Li·(thf)2 mit GeCl2·1,4-Dioxan erreicht

Nystagmus Assessments Documented by Emergency Physicians in Acute Dizziness Presentations: A Target for Decision Support?

Objectives:  Dizziness is a common presenting complaint to the emergency department (ED), and emergency physicians (EPs) consider these presentations a priority for decision support. Assessing for nystagmus and defining its features are important steps for any acute dizziness decision algorithm. The authors sought to describe nystagmus documentation in routine ED care to determine if nystagmus assessments might be an important target in decision support efforts. Methods:  Medical records from ED visits for dizziness were captured as part of a surveillance study embedded within an ongoing population‐based cohort study. Visits with documentation of a nystagmus assessment were reviewed and coded for presence or absence of nystagmus, ability to draw a meaningful inference from the description, and coherence with the final EP diagnosis when a peripheral vestibular diagnosis was made. Results:  Of 1,091 visits for dizziness, 887 (81.3%) documented a nystagmus assessment. Nystagmus was present in 185 of 887 (20.9%) visits. When nystagmus was present, no further characteristics were recorded in 48 of the 185 visits (26%). The documentation of nystagmus (including all descriptors recorded) enabled a meaningful inference about the localization or cause in only 10 of the 185 (5.4%) visits. The nystagmus description conflicted with the EP diagnosis in 113 (80.7%) of the 140 visits that received a peripheral vestibular diagnosis. Conclusions:  Nystagmus assessments are frequently documented in acute dizziness presentations, but details do not generally enable a meaningful inference. Recorded descriptions usually conflict with the diagnosis when a peripheral vestibular diagnosis is rendered. Nystagmus assessments might be an important target in developing decision support for dizziness presentations.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/86927/1/j.1553-2712.2011.01093.x.pd

Vascular health, diabetes, APOE and dementia: the Aging, Demographics, and Memory Study.

INTRODUCTION: Evidence from clinical samples and geographically limited population studies suggests that vascular health, diabetes and apolipoprotein epsilon4 (APOE) are associated with dementia. METHODS: A population-based sample of 856 individuals aged 71 years or older from all contiguous regions of the United States received an extensive in-home clinical and neuropsychological assessment in 2001-2003. The relation of hypertension, diabetes, heart disease, stroke, medication usage, and APOE epsilon4 to dementia was modelled using adjusted multivariable logistic regression. RESULTS: Treated stroke (odds ratio [OR] 3.8, 95% confidence interval [CI] 2.0, 7.2), untreated stroke (OR 3.5, 95% CI 1.7, 7.3), and APOE epsilon4 (OR 2.8, 95% CI 1.7, 4.5) all increased the odds of dementia. Treated hypertension was associated with lower odds of dementia (OR 0.5, 95% CI 0.3, 1.0). Diabetes and heart disease were not significantly associated with dementia. A significant interaction was observed between APOE epsilon4 and stroke (P = 0.001). CONCLUSIONS: Data from the first dementia study that is representative of the United States population suggest that stroke, the APOE epsilon4 allele and their interaction are strongly associated with dementia.RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are

Evaluating the relationship between interannual variations in the Antarctic ozone hole and Southern Hemisphere surface climate in chemistry-climate models

Studies have recently reported statistically significant relationships between observed year-to-year spring Antarctic ozone variability and the Southern Hemisphere Annular Mode and surface temperatures in spring-summer. This study investigates whether current chemistry-climate models (CCMs) can capture these relationships, in particular, the connection between November total column ozone (TCO) and Australian summer surface temperatures, where years with anomalously high TCO over the Antarctic polar cap tend to be followed by warmer summers. The interannual ozone-temperature teleconnection is examined over the historical period in the observations and simulations from the Whole Atmosphere Community Climate Model (WACCM) and nine other models participating in the Chemistry-Climate Model Initiative (CCMI). There is a systematic difference between the WACCM experiments forced with prescribed observed sea surface temperatures (SSTs) and those with an interactive ocean. Strong correlations between TCO and Australian temperatures are only obtained for the uncoupled experiment, suggesting that the SSTs could be important for driving both variations in Australian temperatures and the ozone hole, with no causal link between the two. Other CCMI models also tend to capture this relationship with more fidelity when driven by observed SSTs, though additional research and targeted modelling experiments are required to determine causality and further explore the role of model biases and observational uncertainty. The results indicate that CCMs can reproduce the relationship between spring ozone and summer Australian climate reported in observational studies, suggesting that incorporating ozone variability could improve seasonal predictions, however more work is required to understand the difference between the coupled and uncoupled simulations

Evaluating the relationship between interannual variations in the Antarctic ozone hole and Southern Hemisphere surface climate in chemistry-climate models

Studies have recently reported statistically significant relationships between observed year-to-year spring Antarctic ozone variability and the Southern Hemisphere Annular Mode and surface temperatures in spring-summer. This study investigates whether current chemistry-climate models (CCMs) can capture these relationships, in particular, the connection between November total column ozone (TCO) and Australian summer surface temperatures, where years with anomalously high TCO over the Antarctic polar cap tend to be followed by warmer summers. The interannual ozone-temperature teleconnection is examined over the historical period in the observations and simulations from the Whole Atmosphere Community Climate Model (WACCM) and nine other models participating in the Chemistry-Climate Model Initiative (CCMI). There is a systematic difference between the WACCM experiments forced with prescribed observed sea surface temperatures (SSTs) and those with an interactive ocean. Strong correlations between TCO and Australian temperatures are only obtained for the uncoupled experiment, suggesting that the SSTs could be important for driving both variations in Australian temperatures and the ozone hole, with no causal link between the two. Other CCMI models also tend to capture this relationship with more fidelity when driven by observed SSTs, though additional research and targeted modelling experiments are required to determine causality and further explore the role of model biases and observational uncertainty. The results indicate that CCMs can reproduce the relationship between spring ozone and summer Australian climate reported in observational studies, suggesting that incorporating ozone variability could improve seasonal predictions, however more work is required to understand the difference between the coupled and uncoupled simulations

Large-Scale Transport into the Arctic: The Roles of the Midlatitude Jet and the Hadley Cell

Transport from the Northern Hemisphere (NH) midlatitudes to the Arctic plays a crucial role in determining the abundance of trace gases and aerosols that are important to Arctic climate via impacts on radiation and chemistry. Here we examine this transport using an idealized tracer with a fixed lifetime and predominantly midlatitude land-based sources in models participating in the Chemistry Climate Model Initiative (CCMI). We show that there is a 25%-45% difference in the Arctic concentrations of this tracer among the models. This spread is correlated with the spread in the location of the Pacific jet, as well as the spread in the location of the Hadley Cell (HC) edge, which varies consistently with jet latitude. Our results suggest that it is likely that the HC-related zonal-mean meridional transport rather than the jet-related eddy mixing is the major contributor to the inter-model spread in the transport of land-based tracers into the Arctic. Specifically, in models with a more northern jet, the HC generally extends further north and the tracer source region is mostly covered by surface southward flow associated with the lower branch of the HC, resulting in less efficient transport poleward to the Arctic. During boreal summer, there are poleward biases in jet location in free-running models, and these models likely underestimate the rate of transport into the Arctic. Models using specified dynamics do not have biases in the jet location, but do have biases in the surface meridional flow, which may result in differences in transport into the Arctic. In addition to the land-based tracer, the midlatitude-to-Arctic transport is further examined by another idealized tracer with zonally uniform sources. With equal sources from both land and ocean, the inter-model spread of this zonally uniform tracer is more related to variations in parameterized convection over oceans rather than variations in HC extent, particularly during boreal winter. This suggests that transport of land-based and oceanic tracers or aerosols towards the Arctic differs in pathways and therefore their corresponding inter-model variabilities result from different physical processes

Tobacco smoking as a risk factor of bronchioloalveolar carcinoma of the lung: pooled analysis of seven case–control studies in the International Lung Cancer Consortium (ILCCO)

Background: The International Lung Cancer Consortium (ILCCO) was established in 2004, based on the collaboration of research groups leading large molecular epidemiology studies of lung cancer that are ongoing or have been recently completed. This framework offered the opportunity to investigate the role of tobacco smoking in the development of bronchioloalveolar carcinoma (BAC), a rare form of lung cancer. Methods: Our pooled data comprised seven case–control studies from the United States, with detailed information on tobacco smoking and histology, which contributed 799 cases of BAC and 15,859 controls. We estimated the odds ratio of BAC for tobacco smoking, using never smokers as a referent category, after adjustment for age, sex, race, and study center. Results: The odds ratio of BAC for ever smoking was 2.47 (95% confidence interval [CI] 2.08, 2.93); the risk increased linearly with duration, amount, and cumulative cigarette smoking and persisted long after smoking cessation. The proportion of BAC cases attributable to smoking was 0.47 (95% CI 0.39, 0.54). Conclusions: This analysis provides a precise estimate of the risk of BAC for tobacco smoking

Avelumab in paediatric patients with refractory or relapsed solid tumours: dose-escalation results from an open-label, single-arm, phase 1/2 trial

Background: We report dose-escalation results from an open-label, phase 1/2 trial evaluating avelumab (anti-PD-L1) in paediatric patients with refractory/relapsed solid tumours. Methods: In phase 1, patients aged \u3c 18 years with solid (including central nervous system [CNS]) tumours for which standard therapy did not exist or had failed were enrolled in sequential cohorts of 3–6 patients. Patients received avelumab 10 or 20 mg/kg intravenously every 2 weeks. Primary endpoints were dose-limiting toxicities (DLTs) and grade ≥ 3 treatment-emergent adverse events (AEs). Results: At data cut-off (27 July 2021), 21 patients aged 3–17 years had received avelumab 10 mg/kg (n = 6) or 20 mg/kg (n = 15). One patient had three events that were classified as a DLT (fatigue with hemiparesis and muscular weakness associated with pseudoprogression; 20 mg/kg cohort). Grade ≥ 3 AEs occurred in five (83%) and 11 (73%) patients in the 10 and 20 mg/kg cohorts, respectively, and were treatment-related in one patient (7%; grade 3 [DLT]) in the 20 mg/kg cohort. Avelumab exposure in paediatric patients receiving 20 mg/kg dosing, but not 10 mg/kg, was comparable or higher compared with approved adult dosing (10 mg/kg or 800 mg flat dose). No objective responses were observed. Four patients with CNS tumours (20 mg/kg cohort) achieved stable disease, which was ongoing in two patients with astrocytoma at cut-off (for 24.7 and 30.3 months). Conclusion: In paediatric patients with refractory/relapsed solid tumours, avelumab monotherapy showed a safety profile consistent with previous adult studies, but clinical benefits were limited