Delocalized π‐electrons in 2‐oxazoline rings resulting in negatively charged nitrogen atoms: revealing the selectivity during the initiation of cationic ring‐opening polymerizations

The inventory of the single‐crystal X‐ray structures of aliphatic and aromatic 2‐oxazolines, namely 2‐nonyl‐2‐oxazoline, 2,2′‐tetramethylenebis(2‐oxazoline) and 2‐phenyl‐2‐oxazoline, reveals significant delocalization of π‐electrons along the N? C? O segment. The delocalization of π‐electrons is stabilized by inductive and resonance contributions of the side‐chains; in 2‐phenyl‐2‐oxazoline, also π‐arene interactions between the benzene ring and the C? N and the C? O bond stabilize the crystalline phase. This delocalization gives a partial negative charge to the nitrogen atom and a partial positive charge to the oxygen atom. The partial negative charge of the nitrogen atom makes this atom the exclusive reaction partner also for highly reactive non‐selective cations, which explains the regioselectivity of electrophilic attacks in cationic ring‐opening polymerizations. Copyright © 2011 Society of Chemical Industry     

Oberfl?chennahe Geothermie und ihre potenziellen Auswirkungen auf Grundwasser?kosysteme

The use of shallow geothermal energy is a thriving technology. Still, its impact on the ecology of subsurface habitats has not been adequately investigated. Biological processes are substantially influenced by temperature. In field and laboratory investigations comprising a temperature range from 2 to 45?°C we show, that the diversity and structure of aquifer microbial communities is significantly influenced by temperature. Microbial biomass and activities are shown to additionally depend on the availability of nutrients and substrates in the groundwater. Selected groundwater invertebrates exhibited little tolerance towards mid- and long-term exposure to increased temperatures. Our results allow first recommendations towards the design, authorization, construction and operation of shallow geothermal energy facilities in an ecologically sustainable way.     

Characterization of the Gene Cluster CYP264B1‐geoA from Sorangium cellulosum So ce56: Biosynthesis of (+)‐Eremophilene and Its Hydroxylation

Terpenoids can be found in almost all forms of life; however, the biosynthesis of bacterial terpenoids has not been intensively studied. This study reports the identification and functional characterization of the gene cluster CYP264B1–geoA from Sorangium cellulosum So ce56. Expression of the enzymes and synthesis of their products for NMR analysis and X‐ray diffraction were carried out by employing an Escherichia coli whole‐cell conversion system that provides the geoA substrate farnesyl pyrophosphate through simultaneous overexpression of the mevalonate pathway genes. The geoA product was identified as a novel sesquiterpene, and assigned NMR signals unambiguously proved that geoA is an (+)‐eremophilene synthase. The very tight binding of (+)‐eremophilene (～0.40 μM ), which is also available in S. cellulosum So ce56, and its oxidation by CYP264B1 suggest that the CYP264B1–geoA gene cluster is required for the biosynthesis of (+)‐eremophilene derivatives.     

Receptor‐Mediated Uptake of Boron‐Rich Neuropeptide Y Analogues for Boron Neutron Capture Therapy

Peptidic ligands selectively targeting distinct G protein‐coupled receptors that are highly expressed in tumor tissue represent a promising approach in drug delivery. Receptor‐preferring analogues of neuropeptide Y (NPY) bind and activate the human Y₁ receptor subtype (hY₁ receptor), which is found in 90 % of breast cancer tissue and in all breast‐cancer‐derived metastases. Herein, novel highly boron‐loaded Y₁‐receptor‐preferring peptide analogues are described as smart shuttle systems for carbaboranes as ¹⁰B‐containing moieties. Various positions in the peptide were screened for their susceptibility to carbaborane modification, and the most promising positions were chosen to create a multi‐carbaborane peptide containing 30 boron atoms per peptide with excellent activation and internalization patterns at the hY₁ receptor. Boron uptake studies by inductively coupled plasma mass spectrometry revealed successful uptake of the multi‐carbaborane peptide into hY₁‐receptor‐expressing cells, exceeding the required amount of 10⁹ boron atoms per cell. This result demonstrates that the NPY/hY receptor system can act as an effective transport system for boron‐containing moieties.     

Comparative Anti-Inflammatory Effects of Salix Cortex Extracts and Acetylsalicylic Acid in SARS-CoV-2 Peptide and LPS-Activated Human In Vitro Systems

The usefulness of anti-inflammatory drugs as an adjunct therapy to improve outcomes in COVID-19 patients is intensely discussed in this paper. Willow bark (Salix cortex) has been used for centuries to relieve pain, inflammation, and fever. Its main active ingredient, salicin, is metabolized in the human body into salicylic acid, the precursor of the commonly used pain drug acetylsalicylic acid (ASA). Here, we report on the in vitro anti-inflammatory efficacy of two methanolic Salix extracts, standardized to phenolic compounds, in comparison to ASA in the context of a SARS-CoV-2 peptide challenge. Using SARS-CoV-2 peptide/IL-1β- or LPS-activated human PBMCs and an inflammatory intestinal Caco-2/HT29-MTX co-culture, Salix extracts, and ASA concentration-dependently suppressed prostaglandin E2 (PGE₂), a principal mediator of inflammation. The inhibition of COX-2 enzyme activity, but not protein expression was observed for ASA and one Salix extract. In activated PBMCs, the suppression of relevant cytokines (i.e., IL-6, IL-1β, and IL-10) was seen for both Salix extracts. The anti-inflammatory capacity of Salix extracts was still retained after transepithelial passage and liver cell metabolism in an advanced co-culture model system consisting of intestinal Caco-2/HT29-MTX cells and differentiated hepatocyte-like HepaRG cells. Taken together, our in vitro data suggest that Salix extracts might present an additional anti-inflammatory treatment option in the context of SARS-CoV-2 peptides challenge; however, more confirmatory data are needed.     

Metformin Protects against Radiation-Induced Acute Effects by Limiting Senescence of Bronchial-Epithelial Cells

Radiation-induced damage to normal lung parenchyma remains a dose-limiting factor in thorax-associated radiotherapy (RT). Severe early and late complications with lungs can increase the risk of morbidity in cancer patients after RT. Herein, senescence of lung epithelial cells following RT-induced cellular stress, or more precisely the respective altered secretory profile, the senescence-associated secretory phenotype (SASP), was suggested as a central process for the initiation and progression of pneumonitis and pulmonary fibrosis. We previously reported that abrogation of certain aspects of the secretome of senescent lung cells, in particular, signaling inhibition of the SASP-factor Ccl2/Mcp1 mediated radioprotection especially by limiting endothelial dysfunction. Here, we investigated the therapeutic potential of a combined metformin treatment to protect normal lung tissue from RT-induced senescence and associated lung injury using a preclinical mouse model of radiation-induced pneumopathy. Metformin treatment efficiently limited RT-induced senescence and SASP expression levels, thereby limiting vascular dysfunctions, namely increased vascular permeability associated with increased extravasation of circulating immune and tumor cells early after irradiation (acute effects). Complementary in vitro studies using normal lung epithelial cell lines confirmed the senescence-limiting effect of metformin following RT finally resulting in radioprotection, while fostering RT-induced cellular stress of cultured malignant epithelial cells accounting for radiosensitization. The radioprotective action of metformin for normal lung tissue without simultaneous protection or preferable radiosensitization of tumor tissue might increase tumor control probabilities and survival because higher radiation doses could be used.     

Perceived overprotection and distress in adults with visual impairment.

Objective: To investigate the role of perceived overprotection, a problematic aspect of social support, as a risk factor for distress among adults with chronic vision impairment. Study Design: Cross-sectional study using telephone interviews. Setting: Vision rehabilitation agency. Participants: One hundred fourteen adults with vision impairment (ages 24-64). Measures: 18-item Overprotection Scale for Adults, 20-item Center for Epidemiological Studies-Depression Scale, 21-item Beck Anxiety Inventory. Results: Hierarchical multiple regression analyses demonstrated that higher levels of perceived overprotection were associated with higher levels of depressive symptomatology as well as higher levels of anxiety. Conclusions: Vision rehabilitation programs should address issues around perceived overprotection. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Colloidal quantum dots in all-dielectric high-Q pillar microcavities

We have fabricated all-dielectric high-Q optical pillar resonators with embedded colloidal CdSe/ZnS quantum dots or rods as light emitters by focused ion beam milling. Three-dimensional light confinement and distinct pillar microcavity modes are observed. Results from a waveguide model for the mode patterns and their spectral positions are in excellent agreement with the experimental data. Cavities with elliptical cross sections show higher quality factors in the short axis direction than do circular resonators of the same cross-sectional area.