Hydroalumination of Cl‐functionalized alkynylgermanes yielded mixed Al/Ge compounds (1). The Cl atoms adopted bridging positions between the Ge and Al atoms to form four‐membered GeCAlCl heterocycles ...with relatively long endocyclic Ge–Cl and Al–C bonds. Reactions with isocyanates resulted in the insertion of the heterocumulenes into both activated bonds and the formation of four‐membered GeC2N heterocycles, which featured exocyclic C–C and C–O double bonds with C–O oxygen atoms coordinated to ClAltBu2 molcules (2). An intermediate (3) was isolated with Ad‐NCO (Ad = 1‐adamantyl) from the insertion of isocyanate into the endocyclic Al–C bond. These products are characterized by intact Ge–Cl bonds and a chelating coordination of the Al atoms by the OCN groups. They rearranged at elevated temperature to yield compounds of type 2. Quantum‐chemical calculations were applied to evaluate the thermodynamics of these isocyanate insertion reactions. An azide reacted similarly by insertion into the Al–C and Ge–Cl bonds and afforded a GeCN3 heterocycle with an intact N3 group.
σ‐Bond activation results from an intramolecular interaction between Al and Cl atoms in dialkylaluminum‐functionalized chlorogermanes. The concomitant weakening of the Ge–Cl and Al–C(vinyl) bonds facilitates insertion reactions with isocyanate and azide and the formation of unusual structural motifs by C–C and C–N bond formation.
The active Al/N Lewis pair, (Me
C)
Al-C(SiMe
)=C(H)-N(CHMe-CH
)
CH
(2), reacted with isocyanates to afford a fascinating variety of products. One equivalent of Ph-N=C=O yielded by the release of ...H-C≡C-SiMe
an urea-type ligand which coordinated the Al atom in a chelating manner (4). Dipp-N=C=O gave a similar product, but the bulky substituent hindered the approach of the N-aryl group to Al. A situation similar to that of frustrated Lewis pairs resulted in the coordination of the alkyne to the Al and N atoms (6) by C-H bond activation. Dual insertion was observed upon treatment of 2 with two equivalents of isocyanates (8 to 11). The preferred formation of cyclic oligomers is prevented by the specific cooperative properties of the Lewis pair. A metal-free dimeric isocyanate (13) was formed by hydrolysis. Replacement of the CMe
groups in 2 by less bulky isobutyl groups (7) afforded the insertion of two isocyanate molecules into the Al-vinyl bonds without alkyne elimination. The resulting highly functionalised compound had a chain formed by two isocyanates and the organic backbone of the Lewis pair. Me
C-N=C=O and 2 afforded a unique compound (14) in which an isocyanate ligand connects two molecules of 2 by the release of dimethylpiperidine. The combination of a C
building block and two C
groups gave an unsaturated branched C
moiety by the simultaneous formation of two C-C bonds. The molecular structure showed an interaction between an Al atom and a C-C π-bond.
Das »Jahrbuch der Deutschen Schillergesellschaft« ist ein literaturwissenschaftliches Periodikum, das vorwiegend Beiträge zur deutschsprachigen Literatur von der Aufklärung bis zur Gegenwart ...veröffentlicht. Diese Zeitspanne entspricht den Sammelgebieten des Deutschen Literaturarchivs Marbach, das von der Deutschen Schillergesellschaft getragen wird.
Das »Jahrbuch der Deutschen Schillergesellschaft« ist ein literaturwissenschaftliches Periodikum, das vorwiegend Beiträge zur deutschsprachigen Literatur von der Aufklärung bis zur Gegenwart ...veröffentlicht. Diese Zeitspanne entspricht den Sammelgebieten des Deutschen Literaturarchivs Marbach, das von der Deutschen Schillergesellschaft getragen wird.
Das »Jahrbuch der Deutschen Schillergesellschaft« ist ein literaturwissenschaftliches Periodikum, das vorwiegend Beiträge zur deutschsprachigen Literatur von der Aufklärung bis zur Gegenwart ...veröffentlicht. Diese Zeitspanne entspricht den Sammelgebieten des Deutschen Literaturarchivs Marbach, das von der Deutschen Schillergesellschaft getragen wird.
Necrotising pancreatitis, and particularly infected necrosis, are still associated with high morbidity and mortality. Since 2011, a step-up approach with lower morbidity rates compared to initial ...open necrosectomy has been established. However, mortality and complication rates of this complex treatment are hardly studied thereafter.
The German Pancreatitis Study Group performed a multicenter, retrospective study including 220 patients with necrotising pancreatitis requiring intervention, treated at 10 hospitals in Germany between January 2008 and June 2014. Data were analysed for the primary endpoints "severe complications" and "mortality" as well as secondary endpoints including "length of hospital stay", "follow up", and predisposing or prognostic factors.
Of all patients 13.6% were treated primarily with surgery and 86.4% underwent a step-up approach. More men (71.8%) required intervention for necrotising pancreatitis. The most frequent etiology was biliary (41.4%) followed by alcohol (29.1%). Compared to open necrosectomy, the step-up approach was associated with a lower number of severe complications (primary composite endpoint including sepsis, persistent multiorgan dysfunction syndrome (MODS) and erosion bleeding: 44.7% vs. 73.3%), lower mortality (10.5% vs. 33.3%) and lower rates of diabetes mellitus type 3c (4.7% vs. 33.3%). Low hematocrit and low blood urea nitrogen at admission as well as a history of acute pancreatitis were prognostic for less complications in necrotising pancreatitis. A combination of drainage with endoscopic necrosectomy resulted in the lowest rate of severe complications.
A step-up approach starting with minimal invasive drainage techniques and endoscopic necrosectomy results in a significant reduction of morbidity and mortality in necrotising pancreatitis compared to a primarily surgical intervention.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
IMPORTANCE Helicobacter pylori is a major cause of gastritis and gastroduodenal ulcer disease and can cause cancer. H pylori prevalence is as high as 90% in some developing countries but 10% of a ...given population is never colonized, regardless of exposure. Genetic factors are hypothesized to confer H pylori susceptibility. OBJECTIVE To identify genetic loci associated with H pylori seroprevalence in 2 independent population-based cohorts and to determine their putative pathophysiological role by whole-blood RNA gene expression profiling. DESIGN, SETTING, AND PARTICIPANTS Two independent genome-wide association studies (GWASs) and a subsequent meta-analysis were conducted for anti-H pylori IgG serology in the Study of Health in Pomerania (SHIP) (recruitment, 1997-2001 n = 3830) as well as the Rotterdam Study (RS-I) (recruitment, 1990-1993) and RS-II (recruitment, 2000-2001 n = 7108) populations. Whole-blood RNA gene expression profiles were analyzed in RS-III (recruitment, 2006-2008 n = 762) and SHIP-TREND (recruitment, 2008-2012 n = 991), and fecal H pylori antigen in SHIP-TREND (n = 961). MAIN OUTCOMES AND MEASURES H pylori seroprevalence. RESULTS Of 10 938 participants, 6160 (56.3%) were seropositive for H pylori. GWASs identified the toll-like receptor (TLR) locus (4p14; top-ranked single-nucleotide polymorphism (SNP), rs10004195; P = 1.4 × 10−18; odds ratio, 0.70 95% CI, 0.65 to 0.76) and the FCGR2A locus (1q23.3; top-ranked SNP, rs368433; P = 2.1 × 10−8; odds ratio, 0.73 95% CI, 0.65 to 0.81) as associated with H pylori seroprevalence. Among the 3 TLR genes at 4p14, only TLR1 was differentially expressed per copy number of the minor rs10004195-A allele (β = −0.23 95% CI, −0.34 to −0.11; P = 2.1 × 10−4). Individuals with high fecal H pylori antigen titers (optical density >1) also exhibited the highest 25% of TLR1 expression levels (P = .01 by χ2 test). Furthermore, TLR1 exhibited an Asn248Ser substitution in the extracellular domain strongly linked to the rs10004195 SNP. CONCLUSIONS AND RELEVANCE GWAS meta-analysis identified an association between TLR1 and H pylori seroprevalence, a finding that requires replication in nonwhite populations. If confirmed, genetic variations in TLR1 may help explain some of the observed variation in individual risk for H pylori infection.
The Al/P-based frustrated Lewis pair (FLP) Mes2PC(CHPh)Al(CMe3)2 (1) reacted with boron halides BX3 (X = F, Cl, Br, I) as an ambiphilic ligand to form complexes (2–5) in which the boron atoms ...were coordinated to phosphorus and one of the halogen atoms to aluminum. Nonplanar five-membered heterocycles resulted that had five different ring atoms (AlCPBX). The distance of the bridging halogen atoms to the AlCPB plane increased steadily with the radius of the halogen atoms. Only the BF3 adduct showed a dynamic behavior in solution at room temperature with equivalent tert-butyl or mesityl groups in the NMR spectra, while in other cases, the rigid conformation led to the magnetic inequivalence of the substituents at Al and P with well-resolved signals for each group. The BBr3 and BI3 complexes underwent in solution at room temperature a spontaneous stereoselective rearrangement with the concomitant release of isobutene. The obtained products, Mes2P(μ-CCHPh)(μ-HBX2)AlX(CMe3) (6 and 7) may be viewed as unique adducts of a modified new Al/P-based FLP, Mes2PC(CHPh)AlX(CMe3) (X = Br, I), with dihalogenboranes, HBX2. The trapped boranes are either completely unknown (X = I) or unstable in the free form. Quantum–chemical calculations suggest an ionic rearrangement mechanism via the formation of a borenium cation, β-hydride elimination, and hydride transfer. The bromine migration from boron to aluminum corresponds to a formal suprafacial 1,3-sigmatropic rearrangement.
Zinc (Zn) and its alloys have been considered as potential materials for osteosynthesis implants. Nonetheless, the relatively slow degradation rates within bone environments impede their further ...application. Herein, sandblasting surface treatment with two Al2O3 particle sizes (125 μm and 250 μm) was employed to accelerate the degradation rates of Zn and two Zn alloys, a Zn4Ag and a Zn-2Ag-1.8Au-0.2V (wt%). The degradation processes of Zn and Zn alloys were significantly increased after sandblasting treatment mainly due to the increased surface roughness and embedded Al2O3 particles in the surfaces. However, an increase of sandblasting particle size from 125 μm to 250 μm did not affect the degradation rates. Moreover, the mean relative metabolic activities of Saos-2 osteoblasts below 70% were observed for alloys treated with 250 μm Al2O3 particles, indicating apparent cytotoxic effects. The results showed that the size of the sandblasting particles had no direct effect on the degradation rate but on the cytotoxicity. Therefore, sandblasting treatment with appropriate particles might be a promising surface modification to accelerate the biodegradability of Zn and its alloys.
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•Zn and its alloys were sandblasted using alumina oxide abrasives of different size.•Degradation rate of Zn and its alloys was significantly accelerated after sandblasting.•Cytotoxicity of Zn and its alloys can be minimized by careful sandblasting particle selection.•Sandblasting might be a promising approach to adjust biodegradability of Zn and its alloys.
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