Publications by authors named "Neumann H"

A general and selective palladium-catalyzed alkoxycarbonylation of all kinds of alkenes with formic acid (HCOOH, FA) is described. Terminal, di-, tri-, and tetra-substituted including functionalized olefins are converted into linear esters with high yields and regioselectivity. Key-to-success is the use of specific palladium catalysts containing ligands with built-in base, e.

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The genetic incorporation of unnatural amino acids (UAAs) into proteins by amber suppression technology provides unique avenues to study protein structure, function and interactions both in vitro and in living cells and organisms. This approach has been particularly useful for studying mechanisms of epigenetic chromatin regulation, since these extensively involve dynamic changes in structure, complex formation and posttranslational modifications that are difficult to access by traditional approaches. Here, we review recent achievements in this field, emphasizing UAAs that help to unravel protein-protein interactions in cells by photo-crosslinking or that allow the biosynthesis of proteins with defined posttranslational modifications for studying their function and turnover in vitro and in cells.

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Zenker's diverticulum (ZD), or pharyngeal pouch, is an anatomical defect characterized by herniation of the posterior pharyngeal wall through Killian's dehiscence, and may result in dysphagia and regurgitation. Multiple therapeutic modalities including surgery, rigid and flexible endoscopy have been developed to manage ZD. Although surgical management with open and endoscopically assisted techniques have historically been the mainstay of ZD treatment, minimally invasive flexible endoscopic techniques, carried out under conscious sedation, are increasingly favored.

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The installation of unnatural amino acids into proteins of living cells is an enabling technology that facilitates an enormous number of applications. UV-activatable crosslinker amino acids allow the formation of a covalent bond between interaction partners in living cells with nearly perfect spatial and temporal control. Here, we describe how this method can be employed to map chromatin interactions and to follow these interactions across the cell cycle in synchronized yeast populations.

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Background: Pheochromocytomas (PH) and paragangliomas (PGL) are rare tumours in children accounting for about 1% of the paediatric hypertension. While minimally invasive surgical techniques are well established in adult patients with PH, the experience in children is extremely limited. To the best of our knowledge, we herewith present the largest series of young patients operated on chromaffin tumours by minimally invasive access.

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Crohn's disease and ulcerative colitis are chronic inflammatory bowel diseases (IBD) causing severe damage of the luminal gastrointestinal tract. Differential diagnosis between both disease entities is sometimes awkward requiring a multifactorial pathway, including clinical and laboratory data, radiological findings, histopathology and endoscopy. Apart from disease diagnosis, endoscopy in IBD plays a major role in prediction of disease severity and extent (i.

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First descriptions of diseases attract tremendous interest because they reveal scientific insight even in retrospect. Max Schottelius, the pathologist contributing the first histological description of pheochromocytoma, remains anonymous. We reviewed the description by Schottelius and weighed the report in modern context.

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Background And Study Aims:  Endoscopic treatment of malignant colorectal polyps is often challenging, especially for early rectal cancer (ERC) localized close to the dentate line. Conversely, the surgical approach may result in temporary or definitive stoma and in frequent post-surgical complications. The Full-Thickness Resection Device (FTRD ) System (Ovesco Endoscopy, Tübingen, Germany) is a novel system that, besides having other indications, appears to be promising for wall-thickness excision of intestinal T1 carcinoma following incomplete endoscopic resection.

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Background: Early-life sensitization to indoor allergens predicts asthma development. The aim of this study was to compare allergen concentrations in day-care centers (DCC) with those in private homes.

Methods: Settled airborne dust was collected 4 times a year from 20 German DCC (620 samples) and from the homes of children and day-care workers (602 samples) using electrostatic dust collectors (EDC).

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For the first time, the bidentate phosphinite ligand 1,2-bis(di-tert-butylphosphinoxy)ethane (tBu POCH CH OPtBu ) was synthesized. In the presence of this ligand, various N-acyl enamides were obtained in good yields and chemoselectivity by Pd-catalyzed carbonylation reaction of imines containing α-H. Meanwhile, imines without α-H could be transformed to N-acyl imines, which form highly hindered amides by straightforward addition of Grignard reagents.

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Neuroendocrine tumors (NET) represent the variability of almost benign lesions either secreting hormones occurring as a single lesion up to malignant lesions with metastatic potential. Treatment of NET is usually performed by surgical resection. Due to the rarity of NET, surgical treatment is mainly based on the experience and recommendations of experts and less on the basis of prospective randomized studies.

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N-Methylated amines play an important role in regulating the biological and pharmaceutical properties of all kinds of life science molecules. In general, this class of compounds is synthesized via reductive amination reactions using high pressure of molecular hydrogen. Thus, on laboratory scale especially in drug discovery, activated (toxic) methyl compounds such as methyl iodide and dimethyl sulfate are still employed, which also generate significant amounts of waste.

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Background And Aims: Assessment of prognostic factors in patients with Crohn's disease (CD) is of pivotal importance for early intervention and "treat-to-target" strategies. Confocal laser endomicroscopy (CLE) enables on-demand in vivo characterization of mucosal inflammatory and architectural changes during endoscopy. We prospectively assessed the value of CLE for prediction of clinical outcome parameters in CD.

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Tetraadamantylbiphosphine (TABP; L1), which showed superior activity in the palladium-catalyzed cyanation of 4-chloroanisole compared to standard phosphines, was synthesized as a new ligand. The generality of the new catalytic system was shown by the cyanation reaction of approximately 30 (hetero)aryl halides including hindered, electron-rich, and electron-poor aryl chlorides. These reactions constitute the first examples of using biphosphine ligands in Pd-catalyzed coupling reactions.

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Background And Study Aim: Advanced endoscopic imaging has revolutionized the characterization of lesions during colonoscopy. The aim of this study was to create a new classification for differentiating subcentimetric hyperplastic and adenomatous polyps, and deeply invasive malignant lesions using blue-light imaging (BLI) with high definition, with and without optical magnification, as well as to assess its interobserver concordance.

Methods: A video library consisting of 48 videos/still images (with/without optical magnification) from 24 histologically verified polyps/cancer with BLI was prospectively created.

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The development of base metal catalysts for the synthesis of pharmaceutically relevant compounds remains an important goal of chemical research. Here, we report that cobalt nanoparticles encapsulated by a graphitic shell are broadly effective reductive amination catalysts. Their convenient and practical preparation entailed template assembly of cobalt-diamine-dicarboxylic acid metal organic frameworks on carbon and subsequent pyrolysis under inert atmosphere.

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Oral Squamous Cell Carcinoma (OSCC) is a common type of cancer of the oral epithelium. Despite their high impact on mortality, sufficient screening methods for early diagnosis of OSCC often lack accuracy and thus OSCCs are mostly diagnosed at a late stage. Early detection and accurate outline estimation of OSCCs would lead to a better curative outcome and a reduction in recurrence rates after surgical treatment.

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Identifying patterns in the effects of temperature on species' population abundances could help develop a general framework for predicting the consequences of climate change across different communities and realms. We used long-term population time series data from terrestrial, freshwater, and marine species communities within central Europe to compare the effects of temperature on abundance across a broad range of taxonomic groups. We asked whether there was an average relationship between temperatures in different seasons and annual abundances of species in a community, and whether species attributes (temperature range of distribution, range size, habitat breadth, dispersal ability, body size, and lifespan) explained interspecific variation in the relationship between temperature and abundance.

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Climate change, land-use change, pollution and exploitation are among the main drivers of species' population trends; however, their relative importance is much debated. We used a unique collection of over 1,000 local population time series in 22 communities across terrestrial, freshwater and marine realms within central Europe to compare the impacts of long-term temperature change and other environmental drivers from 1980 onwards. To disentangle different drivers, we related species' population trends to species- and driver-specific attributes, such as temperature and habitat preference or pollution tolerance.

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The importance of emotions experienced by learners during their interaction with multimedia learning systems, such as serious games, underscores the need to identify sources of information that allow the recognition of learners' emotional experience without interrupting the learning process. Bodily expression is gaining in attention as one of these sources of information. However, to date, the question of how bodily expression can convey different emotions has largely been addressed in research relying on acted emotion displays.

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Full-coverage spatial data of occurrence and a detailed description of habitat requirements of epibenthic communities are needed in many conservation and management contexts. In the North Sea the focus has so far been on small benthic infauna, whereas structure and ecosystem functions of larger epifaunal communities have been largely ignored. This study provides a comprehensive analysis of epibenthic community structure in the south-eastern North Sea, including a detailed inventory of species, diversity and spatially contiguous distribution of communities.

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An effective method for alkoxycarbonylation of (hetero)aryl bromides is developed in the presence of in situ-generated phosphinite ligands BuPOR (R = Bu, Pr, Et or Me). For this purpose commercially available BuPCl was used as the pre-ligand in the presence of different alcohols. For the first time cross coupling reactions with two alcohols - one generating the ligand, the other used as substrate - were developed.

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Preterm birth is a major risk factor for children's development. It affects children's cognitive and intellectual development and is related to impairments in IQ, executive functions, and well-being, with these problems persisting into adulthood. While preterm children's intellectual and cognitive development has been studied in detail, their social development and social-cognitive competencies have received less attention.

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