42,849 results match your criteria Chemie Der Erde-geochemistry[Journal]


Targeting non-apoptotic cell death in cancer treatment by nanomaterials: Recent advances and future outlook.

Nanomedicine 2020 Jul 2:102243. Epub 2020 Jul 2.

Nanotechnology Research Center, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran 13169-43551, Iran; Physical Chemistry I and Research Center of Micro and Nanochemistry (Cμ), University of Siegen, Siegen, Germany. Electronic address:

Many tumors develop resistance to most of the apoptosis-based cancer therapies. In this sense targeting non-apoptotic forms of cell death including necroptosis, autophagy and ferroptosis may have therapeutic benefits in apoptosis-defective cancer cells. Nanomaterials have shown great advantages in cancer treatment owing to their unique characteristics. Read More

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http://dx.doi.org/10.1016/j.nano.2020.102243DOI Listing

Selective magnetic resonance signal suppression by colored Frank excitation.

J Magn Reson 2020 Jun 21;317:106776. Epub 2020 Jun 21.

Institut für Technische und Makromolekulare Chemie, RWTH Aachen University, Worringerweg 2, 52074 Aachen, Germany. Electronic address:

Inspired by the growing interest in miniaturized NMR devices and their applications in material science as well as in chemical and biological research, low power rf excitation is explored. H NMR spectra have been measured with low power Frank excitation and are compared to spectra obtained by single-pulse excitation. Frank excitation consists of a large number of phase-modulated, constant-amplitude rf-pulses. Read More

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http://dx.doi.org/10.1016/j.jmr.2020.106776DOI Listing

Paediatric population pharmacokinetic modelling to assess hydrocortisone replacement dosing regimens in young children.

Eur J Endocrinol 2020 Jul 1. Epub 2020 Jul 1.

C Kloft, Department of Clinical Pharmacy and Biochemistry, Freie Universität Berlin Institute of Pharmacy, Berlin, 12169, Germany.

Context: Accurate hydrocortisone dosing in children with adrenal insufficiency is important to avoid the risks of over and under treatment including iatrogenic Cushing`s syndrome and adrenal crisis.

Objective: To establish a population pharmacokinetic model of hydrocortisone in children and use this to refine hydrocortisone replacement regimens.

Design And Methods: Pharmacokinetic study of hydrocortisone granules, available in 0. Read More

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http://dx.doi.org/10.1530/EJE-20-0231DOI Listing

Supramolecular self-assembly of β3-peptides mediated by Janus-type recognition units.

Chemistry 2020 Jul 4. Epub 2020 Jul 4.

Georg-August-Universitat Gottingen, Institut für Physikalische Chemie, GERMANY.

To gain mechanistic insights, natural systems with biochemical relevance are inspiring for the creation of novel biomimetics with unique properties and functions. Despite progress in rational design and protein engineering, folding and intramolecular organization of individual components into supramolecular structures remains challenging and requires controlled methods. Foldamers like b-peptides are structurally well defined with rigid conformations and suitable for the specific arrangement of recognition units. Read More

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http://dx.doi.org/10.1002/chem.202003107DOI Listing

D-serine - a useful biomarker for renal injury?

Acta Physiol (Oxf) 2020 Jul 3:e13531. Epub 2020 Jul 3.

Institut für Vegetative Physiologie, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.

Nature is full of miracles. One such phenomenon is the existence of enantiomers, molecules that are mirror images of each other. Chirality is wide spread and stereoisomers exhibit similar physical and chemical properties, however, are not identical and may have strikingly different physiological effects. Read More

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http://dx.doi.org/10.1111/apha.13531DOI Listing

Highly Conjugated π-Systems Arising from Cannibalistic Hexadehydro-Diels-Alder Couplings: Cleavage of C-C Single and Triple Bonds.

Chemistry 2020 Jul 3. Epub 2020 Jul 3.

Julius-Maximilians-Universität Würzburg, Institut für Anorganische Chemie, Am Hubland, 97074, Würzburg, GERMANY.

We have investigated the cannibalistic self-trapping reaction of an ortho -benzyne derivative generated from 1,11-bis( p -tolyl)undeca-1,3,8,10-tetrayne in an HDDA reaction. Without adding any specific trapping agent, the highly reactive benzyne is trapped by another bisdiyne molecule in at least three different modes. We have isolated and characterized the resulting products and performed high-level calculations concerning the reaction mechanism. Read More

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http://dx.doi.org/10.1002/chem.202002511DOI Listing

New reactivity patterns in 3H-phosphaallene chemistry [Aryl-P=C=C(H)-tBu] - hydroboration of the C=C bond, deprotonation and trimerisation.

Chemistry 2020 Jul 3. Epub 2020 Jul 3.

Westfalische Wilhelms-Universitat Munster, Fachbereich Chemie, GERMANY.

3H-Phosphaallenes, R-P=C=C(H)-R' ( 3 ), are accessible in a multigram scale on a new and facile route and show a fascinating chemical reactivity. BH 3 (SMe 2 ) and 3a (R = Mes*, R' = t Bu) afforded by hydroboration of the C=C bonds of two phosphaallene molecules an unprecedented borane ( 7 ) with the B atom bound to two P=C double bonds. This compound represents a new FLP based on a B and two P atoms. Read More

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http://dx.doi.org/10.1002/chem.202002506DOI Listing

Solvation and the secondary structure of a proline-containing dipeptide: insights from VCD spectroscopy.

Phys Chem Chem Phys 2020 Jul 3. Epub 2020 Jul 3.

Ruhr-Universität Bochum, Fakultät für Chemie und Biochemie, Organische Chemie II, Universitätsstraße 150, 44801 Bochum, Germany.

In this study we investigate the IR and VCD spectra of the diastereomeric dipeptide Boc-Pro-Phe-(n-propyl) 1 in chloroform-d1 (CDCl3) and the strongly hydrogen bonding solvent dimethylsulfoxide-d6 (DMSO-d6). From comparison of the experimental spectra, the amide II spectral region is identified as marker signature for the stereochemistry of the dipeptide: the homochiral LL-1 features a (+/-)-pattern in the amide II region of the VCD spectrum, while the amide II signature of the diastereomer LD-1 is inverted. Computational analysis of the IR and VCD spectra of LL-1 reveals that the experimentally observed amide II signature is characteristic for a βI-turn structure of the peptide. Read More

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http://dx.doi.org/10.1039/d0cp02283gDOI Listing

A four-parameter system for rationalising the electronic properties of transition metal-radical ligand complexes.

Dalton Trans 2020 Jul 3. Epub 2020 Jul 3.

Institut für Anorganische Chemie, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany.

A system of four principal parameters is reported that provides a unified description of the electronic and chemical properties of radical-ligand coordination compounds. This type of parametrisation applies to compositionally different types of radical-ligands, and the principal parameters rank in the following order: (a) coordination mode (metal-ligand orbital alignment) > (b) metal linkage > (c) ligand charge > (d) geometric strain (on orbital overlap). A series of group-10 metal complexes of an open-shell thiolate-arene-thiolate ligand suits to differentiate between three of the four effects in a clear-cut fashion, which allowed sorting these into a semi-quantitative order for the first time. Read More

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http://dx.doi.org/10.1039/d0dt02237cDOI Listing

Efficient NH-based process to remove chlorine from electron beam deposited ruthenium produced from (η-CH)Ru(CO)Cl.

Sci Rep 2020 Jul 2;10(1):10901. Epub 2020 Jul 2.

Institute for Applied and Physical Chemistry (IAPC), Fachbereich 2 (Chemie/Biologie), University of Bremen, Leobener Str. 5 (NW2), 28359, Bremen, Germany.

The fabrication of Ru nanostructures by focused electron beam induced deposition (FEBID) requires suitable precursor molecules and processes to obtain the pure metal. So far this is problematic because established organometallic Ru precursors contain large organic ligands, such as cyclopentadienyl anions, that tend to become embedded in the deposit during the FEBID process. Recently, (η-CH)Ru(CO)X (X = Cl, Br) has been proposed as an alternative precursor because CO can easily desorb under electron exposure. Read More

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http://dx.doi.org/10.1038/s41598-020-67803-yDOI Listing

Identification of the amino acid position controlling the different enzymatic activities in walnut tyrosinase isoenzymes (jrPPO1 and jrPPO2).

Sci Rep 2020 Jul 2;10(1):10813. Epub 2020 Jul 2.

Universität Wien, Fakultät für Chemie, Institut für Biophysikalische Chemie, Althanstraße 14, 1090, Wien, Austria.

Polyphenol oxidases (PPOs) are ubiquitously distributed among plants, bacteria, fungi and animals. They catalyze the hydroxylation of monophenols (monophenolase activity) and the oxidation of o-diphenols (diphenolase activity) to o-quinones. PPOs are commonly present as an isoenzyme family. Read More

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http://dx.doi.org/10.1038/s41598-020-67415-6DOI Listing

Why do we still cling to spirometry for assessing small airway function?

Eur Respir J 2020 Jul 2;56(1). Epub 2020 Jul 2.

Pneumology and Critical Care Medicine, Thoraxklinik at University Hospital Heidelberg, Translational Lung Research Center Heidelberg (TLRC), Member of German Center for Lung Research (DZL), Heidelberg, Germany.

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http://dx.doi.org/10.1183/13993003.01071-2020DOI Listing

[Basic Knowledge of Drug Pain Therapy in the Palliative Situation].

Dtsch Med Wochenschr 2020 Jul 2;145(13):917-925. Epub 2020 Jul 2.

Klinik für Palliativmedizin, Medizinische Fakultät Uniklinik RWTH Aachen.

This review provides an overview of the basic knowledge of drug pain therapy in the palliative situation. Pain is one of the main symptoms in 60 to 90 % of cancer patients. Pain also develops with neurological and other diseases that occur in end-of-life situations. Read More

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http://dx.doi.org/10.1055/a-1016-9941DOI Listing

Ligand-free ZnS nanoparticles: as easy and green as it gets.

Chem Commun (Camb) 2020 Jul 2. Epub 2020 Jul 2.

Dipartimento di Scienze Chimiche, Università degli Studi di Padova and INSTM UdR, via Marzolo, 1, 35131, Padova, Italy.

The controlled nucleation and crystallization of small pure sphalerite ZnS nanoparticles was achieved under batch and continuous flow conditions at low temperature, in water and without the use of any stabilizing ligand. The obtained nanoparticles displayed a narrow size distribution and high specific surface area. Moreover, the synthesis was suitable to directly obtain stable water-based suspensions and the products were found to be active photocatalysts for the hydrogen evolution reaction. Read More

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http://dx.doi.org/10.1039/d0cc01901aDOI Listing

Heterobimetallic Transition-Metal Carbonyl Clusters: Changing the Charges.

Chemistry 2020 Jul 2. Epub 2020 Jul 2.

Albert-Ludwigs-Universitat Freiburg, Institut für Anorganische und Analytische Chemie, GERMANY.

The homoleptic group 5 carbonylates [M(CO)6]- (M = Nb, Ta) serve as ligands in carbonyl terminated heterobimetallic AgmMn-clusters containing 3 to 11 metal atoms. Based on our serendipitous [Ag6{Nb(CO)6}4]2+ (4a2+) precedent, we established access to such AgmMn-clusters of the composition [Agm{M(CO)6}n]x (M = Nb, Ta; m = 1, 2, 6; n = 2, 3, 4, 5; x = 1-, 1+, 2+). Salts of those molecular cluster ions were synthesized by the reaction of [NEt4][M(CO)6] and Ag[Al(ORF)4] (RF = C(CF3)3) in the correct stoichiometry in 1,2,3,4-tetrafluorobenzene at -35 °C. Read More

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http://dx.doi.org/10.1002/chem.202002339DOI Listing

Allergen Immunotherapy (AIT) in children: a vulnerable population with its own rights and legislation - summary of EMA-initiated multi-stakeholder meeting on Allergen Immunotherapy (AIT) for children, held at Paul-Ehrlich-Institut, Langen, Germany, 16.1.2019.

Clin Transl Allergy 2020 29;10:28. Epub 2020 Jun 29.

Paul-Ehrlich-Institut, Paul-Ehrlich-Str. 51-59, 63225 Langen, Germany.

Concerning development of medicinal products, children belong to a so-called "special population" for which additional legislation applies: Regulation (EC) No 1901/2006 on medicinal products for paediatric use sets up a system of requirements, rewards and incentives to ensure that medicinal products are researched, developed and authorized to meet the therapeutic needs of children. Allergen Immunotherapy (AIT) is believed to contain a strong potential for immunomodulatory effects inducing sustained clinical efficacy after cessation of treatment (disease modifying effect) and thereby may prevent the progression of the atopic march towards asthma manifestation. However, to this day only few data on long-term effects in general exist and even fewer in children. Read More

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http://dx.doi.org/10.1186/s13601-020-00327-wDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7325268PMC

International prospective observational study investigating the disease course and heterogeneity of paediatric-onset inflammatory bowel disease: the protocol of the PIBD-SETQuality inception cohort study.

BMJ Open 2020 Jul 1;10(7):e035538. Epub 2020 Jul 1.

Department of Paediatric Gastroenterology, Erasmus University Medical Center-Sophia Children's Hospital, Rotterdam, The Netherlands

Introduction: Patients with paediatric-onset inflammatory bowel disease (PIBD) may develop a complicated disease course, including growth failure, bowel resection at young age and treatment-related adverse events, all of which can have significant and lasting effects on the patient's development and quality of life. Unfortunately, we are still not able to fully explain the heterogeneity between patients and their disease course and predict which patients will respond to certain therapies or are most at risk of developing a more complicated disease course. To investigate this, large prospective studies with long-term follow-up are needed. Read More

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http://dx.doi.org/10.1136/bmjopen-2019-035538DOI Listing

Protocol for a multinational risk-stratified randomised controlled trial in paediatric Crohn's disease: methotrexate versus azathioprine or adalimumab for maintaining remission in patients at low or high risk for aggressive disease course.

BMJ Open 2020 Jul 1;10(7):e034892. Epub 2020 Jul 1.

Department of Paediatric Gastroenterology, Royal Hospital for Children Glasgow, Glasgow, UK.

Introduction: Immunomodulators such as thiopurines (azathioprine (AZA)/6-mercaptopurine (6MP)), methotrexate (MTX) and biologics such as adalimumab (ADA) are well established for maintenance of remission within paediatric Crohn's disease (CD). It remains unclear, however, which maintenance medication should be used first line in specific patient groups.

Aims: To compare the efficacy of maintenance therapies in newly diagnosed CD based on stratification into high and low-risk groups for severe CD evolution; MTX versus AZA/6MP in low-risk and MTX versus ADA in high-risk patients. Read More

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http://dx.doi.org/10.1136/bmjopen-2019-034892DOI Listing

Does nuclear permutation symmetry allow dynamical localization in symmetric double-well achiral molecules?

J Chem Phys 2020 Jun;152(24):244308

Institut für Chemie, Universität Potsdam, Karl-Liebknecht-Str. 24-25, D-14476 Potsdam-Golm, Germany.

We discuss the effect of molecular symmetry on coherent tunneling in symmetric double-well potentials whose two molecular equilibrium configurations are interconverted by nuclear permutations. This is illustrated with vibrational tunneling in ammonia molecules, electronic tunneling in the dihydrogen cation, and laser-induced rotational tunneling of homonuclear diatomics. In this contribution, we reexamine the textbook picture of coherent tunneling in such potentials, which is depicted with a wavepacket shuttling back and forth between the two potential-wells. Read More

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http://dx.doi.org/10.1063/1.5141746DOI Listing

Step-Economic Synthesis of Biomimetic β-Ketopolyene Thioesters and Demonstration of Their Usefulness in Enzymatic Biosynthesis Studies.

Org Lett 2020 Jul 17;22(13):4955-4959. Epub 2020 Jun 17.

Fakultät Biologie, Chemie und Geologie, Department of Chemistry, Universität Bayreuth, Universitätsstraße 30, 95447 Bayreuth, Germany.

Studies on the biosynthetic processing of polyene thioester intermediates are complicated by limited access to appropriate substrate surrogates. We present a step-economic synthetic access to biomimetic β-ketopolyene thioesters that is based on an Ir-catalyzed reductive Horner-Wadsworth-Emmons olefination. New β-ketotriene and pentaenethioates of pantetheine and -acetylcysteamine were exemplarily synthesized via short and concise routes. Read More

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http://dx.doi.org/10.1021/acs.orglett.0c01348DOI Listing

[Pharmacogenetics in daily practice].

Ned Tijdschr Geneeskd 2020 Jun 4;164. Epub 2020 Jun 4.

Erasmus MC, afd. Klinische Chemie, Rotterdam.

With the exception of a few medical specialties, the implementation of pharmacogenetic tests in daily practice has thus far been limited. The Royal Dutch Pharmacists Association (KNMP) has developed pharmacogenetics-based therapeutic doserecommendations for 80 medicinal product combinations on the basis of a systematic literature review. Genotyping of patients can take place on a reactive or pre-emptive basis; the advantage of pre-emptive genotyping is that it provides genetic information the moment a medicinal product is prescribed. Read More

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Polymer Transformers: Interdigitating Reaction Networks of Fueled Monomer Species to Reconfigure Functional Polymer States.

Angew Chem Int Ed Engl 2020 Jul 1. Epub 2020 Jul 1.

Albert-Ludwigs-University of Freiburg, Institut für Makromolekulare Chemie, Stefan-Meier-Str. 31, 79104, Freiburg, GERMANY.

Adaptivity is an essential trait of life. Its mimicry using chemical systems remains a grand challenge. One type of adaptivity is the reconfiguration of functional system states by correlating sensory inputs. Read More

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http://dx.doi.org/10.1002/anie.202006526DOI Listing

Kinetic studies on the reaction of NO with iron(ii) complexes using low temperature stopped-flow techniques.

Dalton Trans 2020 Jul 1. Epub 2020 Jul 1.

Institut für Anorganische und Analytische Chemie, Justus-Liebig-Universität Gießen, Heinrich-Buff-Ring 17, 35392 Gießen, Germany.

Low temperature stopped-flow techniques were used to investigate the reaction of three different iron(ii) complexes with nitrogen monoxide. The kinetic studies allowed calculation of the activation parameters from the corresponding Eyring plots for all three systems. The reaction of iron(ii) chloride with NO leading to the formation of MNIC (mononitrosyl-iron-complex) and DNIC (dinitrosyl-iron-complex) led to activation parameters of ΔH‡ = 55. Read More

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http://dx.doi.org/10.1039/d0dt01764gDOI Listing

Self-degrading graphene sheets for tumor therapy.

Nanoscale 2020 Jul 1. Epub 2020 Jul 1.

Institut für Chemie und Biochemie, Freie Universität Berlin, Takustr. 3, 14195 Berlin, Germany.

Low biodegradability of graphene derivatives and related health risks are the main limiting factors for their in vivo biomedical applications. Here, we present the synthesis of enzyme-functionalized graphene sheets with self-degrading properties under physiological conditions and their applications in tumor therapy. The synergistic enzyme cascade glucose oxidase and myeloperoxidase are covalently conjugated to the surface of graphene sheets and two-dimensional (2D) platforms are obtained that can produce sodium hypochlorite from glucose. Read More

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http://dx.doi.org/10.1039/d0nr02159hDOI Listing

Varying the sustained release of BMP-2 from chitosan nanogel-functionalized PCL fiber mats by different PCL surface modifications.

J Biomed Mater Res A 2020 Jun 30. Epub 2020 Jun 30.

Technische Universität Braunschweig, Institut für Pharmazeutische Technologie, Braunschweig, Germany.

Polycaprolactone (PCL) fiber mats with different surface modifications were functionalized with a chitosan nanogel coating to attach the growth factor human bone morphogenetic protein 2 (BMP-2). Three different hydrophilic surface modifications were compared with regard to the binding and in vitro release of BMP-2. The type of surface modification and the specific surface area derived from the fiber thickness had an important influence on the degree of protein loading. Read More

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http://dx.doi.org/10.1002/jbm.a.37045DOI Listing

Electrocatalysis as the nexus for sustainable renewable energy. The Gordian knot of activity, stability, and selectivity.

Angew Chem Int Ed Engl 2020 Jun 30. Epub 2020 Jun 30.

Ruhr-Universitat Bochum, Analytische Chemie, Universitätsstr 150, 44780, Bochum, GERMANY.

Coupling harnessing of renewable energies with electro-chemical technologies that convert the omnipresent molecules H 2 O, CO 2 and N 2 into chemical energy carriers and chemical feedstocks is at the frontier towards securing a sustainable green energy future. In this minireview, some weaknesses and incoherencies in the current predominant practices of determining electrocatalytic performance that have not only protracted progress towards realizing functional systems but also obstructed atomic and molecular scale insight into important fundamental properties and phenomena to inform rational bottom-up catalyst design are discussed. We highlight examples of stark discrepancies in material properties and electrocatalytic activity and stability that manifest when materials are tested at conditions of their envisaged deployment as opposed to common laboratory condi-tions and thereby advocate for unified activity-stability correlations at application relevant conditions and disambiguation of reporting elec-trocatalytic performance by contextualization with respect to funda-mental inquisition or progress towards application. Read More

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http://dx.doi.org/10.1002/anie.202007672DOI Listing

Cs[Cl3F10]: A Propeller-Shaped [Cl3F10]- Anion in a Peculiar A[5]B[5] Structure Type.

Angew Chem Int Ed Engl 2020 Jun 30. Epub 2020 Jun 30.

Philipps-Universitat Marburg, Chemie, Hans-Meerwein-Straße 4, 35032, Marburg, GERMANY.

Reaction of CsF with ClF3 leads to Cs[Cl3F10]. It contains a molecular, propeller-shaped [Cl3F10]- anion with a central µ3-F atom and three T-shaped ClF3 molecules coordinated to it. This anion represents the first example of a heteropolyhalide anion of higher ClF3 content than [ClF4]- and is the first Cl-containing interhalogen species with a µ-bridging F atom. Read More

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http://dx.doi.org/10.1002/anie.202007019DOI Listing

SAR Studies of the Leupyrrins: Design and Total Synthesis of Highly Potent Simplified Leupylogs.

Chemistry 2020 Jul 1. Epub 2020 Jul 1.

Universität Bonn, Kekule-Institut für Organische Chemie und Biochemie, Gerhard-Domagk-Str. 1, 53121, Bonn, GERMANY.

Leupyrrins are highly potent antifungal agents. A structure-activity-relationship study of natural and synthetic derivatives is reported which reveals important insights into the biological relevance of several structural subunits leading to the discovery of highly potent but drastically simplified leupylogs that incorporate a stable and readily available aromatic side chain. For their synthesis a concise strategy is described that enables a short and versatile access. Read More

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http://dx.doi.org/10.1002/chem.202002622DOI Listing

Chalcogen bonding interactions in telluroether heterocycles [Te(CH2)m]n (n = 1-4; m = 3-7).

Chemistry 2020 Jun 30. Epub 2020 Jun 30.

University of Oulu, Laboratory of Inorganic Chemistry, Center for Molecular Materials, P.O. Box 3000, 90014, Oulu, FINLAND.

The Te…Te secondary bonding interactions (SBI) in solid heterocyclic telluroethers were explored by preparing and structurally characterizing a series of [Te(CH2)m]n (n = 1-4; m = 3-7) species.  The SBIs in 1,7-Te2(CH2)10, 1,8-Te2(CH2)12, 1,5,9-Te3(CH2)9, 1,8,15-Te3(CH2)18, 1,7,13,19-Te4(CH2)20, 1,8,15,22-Te4(CH2)24, and 1,9,17,25-Te4(CH2)28 led to the tubular packing of the molecules, as has been observed previously for related thio- and selenoether rings. The nature of the intermolecular interactions was explored by solid-state PBE0-D3/pob-TZVP calculations involving periodic boundary conditions. Read More

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http://dx.doi.org/10.1002/chem.202002510DOI Listing

Effectiveness and Tolerability of LABA/LAMA Fixed-Dose Combinations Aclidinium/Formoterol, Glycopyrronium/Indacaterol and Umeclidinium/Vilanterol in the Treatment of COPD in Daily Practice - Results of the Non-Interventional DETECT Study.

Int J Chron Obstruct Pulmon Dis 2020 10;15:1335-1347. Epub 2020 Jun 10.

Insaf - Respiratory Research Institute GmbH, Wiesbaden, Germany.

Background: LABA (long-acting β2-agonists) and/or LAMA (long-acting muscarinic antagonists) represent the first treatment options for patients with symptomatic COPD. Although both display different mechanisms of activity, in combination they have a stronger broncho-dilating effect than monotherapy; hence, a combination of both LABA and LAMA is particularly recommended for patients whose symptoms cannot be sufficiently improved by a single active ingredient. To date, only few data have been collected regarding the therapeutic outcomes of approved LABA/LAMA fixed-dose combinations (FDCs) under everyday (real-life) conditions in non-clinical trial settings. Read More

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http://dx.doi.org/10.2147/COPD.S252354DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7293910PMC

An Integrative Approach of the Fissure Completeness Score and Chartis Assessment in Endobronchial Valve Treatment for Emphysema.

Int J Chron Obstruct Pulmon Dis 2020 9;15:1325-1334. Epub 2020 Jun 9.

Charité Universitätsmedizin Berlin, Campus Virchow Klinikum, Department of Pneumology, Berlin, Germany.

Purpose: Lung volume reduction using one-way endobronchial valves is a bronchoscopic treatment for patients with severe emphysema without collateral ventilation between the treatment target lobe and the ipsilateral lobe(s). CT-scan fissure analysis is often used as a surrogate to predict the absence of collateral ventilation. We aimed to evaluate the predictive value of the fissure completeness score (FCS) compared to the functional Chartis measurement of collateral ventilation and to provide cut-off values of the FCS in patient selection. Read More

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http://dx.doi.org/10.2147/COPD.S242210DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7294564PMC

Day and Night Control of COPD and Role of Pharmacotherapy: A Review.

Int J Chron Obstruct Pulmon Dis 2020 4;15:1269-1285. Epub 2020 Jun 4.

Department of Biomedicine and Internal and Specialistic Medicine (DIBIMIS), University of Palermo, Palermo, Italy.

The topic of 24-hour management of COPD is related to day-to-night symptoms management, specific follow-up and patients' adherence to therapy. COPD symptoms strongly vary during day and night, being worse in the night and early morning. This variability is not always adequately considered in the trials. Read More

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http://dx.doi.org/10.2147/COPD.S240033DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7283230PMC

Vibrational Excitation Hindering an Ion-Molecule Reaction: The c-C_{3}H_{2}^{+}-H_{2} Collision Complex.

Phys Rev Lett 2020 Jun;124(23):233401

I. Physikalisches Institut, Universität zu Köln, Zülpicher Str. 77, D-50937 Köln, Germany.

Experiments within a cryogenic 22-pole ion trap have revealed an interesting reaction dynamic phenomenon, where rovibrational excitation of an ionic molecule slows down a reaction with a neutral partner. This is demonstrated for the low-temperature hydrogen abstraction reaction c-C_{3}H_{2}^{+}+H_{2}, where excitation of the ion into the ν_{7} antisymmetric C-H stretching mode decreased the reaction rate coefficient toward the products c-C_{3}H_{3}^{+}+H. Supported by high-level quantum-chemical calculations, this observation is explained by the reaction proceeding through a c-C_{3}H_{2}^{+}-H_{2} collision complex in the entrance channel, in which the hydrogen molecule is loosely bound to the hydrogen atom of the c-C_{3}H_{2}^{+} ion. Read More

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http://dx.doi.org/10.1103/PhysRevLett.124.233401DOI Listing

Light dynamics of retinal disease-relevant G90D bovine rhodopsin mutant.

Angew Chem Int Ed Engl 2020 Jun 30. Epub 2020 Jun 30.

Goethe-Universitat Frankfurt am Main, Institut für Organische Chemie und Chemische Biologie, Max-von-Laue-Str. 7, 60438, Frankfurt, GERMANY.

The RHO gene encodes the GPCR rhodopsin. Numerous mutations associated with impaired visual cycle have been reported; the G90D mutation leads to a constitutively active mutant form of rhodopsin that causes CSNB disease. We report here on the structure investigation of the retinal configuration and conformation in the binding pocket in the dark and light-activated state by solution and MAS-NMR spectroscopy. Read More

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http://dx.doi.org/10.1002/anie.202003671DOI Listing

Influence of cyclic and acyclic cucurbiturils on the degradation pathways of the chemical warfare agent VX.

Org Biomol Chem 2020 Jun 30. Epub 2020 Jun 30.

Technische Universität Kaiserslautern, Fachbereich Chemie - Organische Chemie, Erwin-Schrödinger-Straße, 67663 Kaiserslautern, Germany.

The highly toxic nerve agent VX is a methylphosphonothioate that degrades via three pathways in aqueous solution, namely through the hydrolysis of the P-O or P-S bonds, or the cleavage of the C-S bond at the 2-aminoethyl residue. In the latter case, an aziridinium ion and a phosphonothioate is formed. Here it is shown that acyclic or cyclic cucurbiturils inhibit these reactions in phosphate buffer at physiological pH and thus stabilise the nerve agent. Read More

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http://dx.doi.org/10.1039/d0ob01167cDOI Listing

Is it really possible to control aromaticity of benzene with light?

Phys Chem Chem Phys 2020 Jun 30. Epub 2020 Jun 30.

Laboratoire de Physique et Chimie Théoriques, CNRS-Université de Lorraine, UMR 7019 ICPM, 1 Bd Arago, 57070 Metz, France.

Recent theoretical investigations claim that tailored laser pulses may selectively steer benzene's aromatic ground state to localized non-aromatic excited states. For instance, it has been shown that electronic wavepackets, involving the two lowest electronic eigenstates, exhibit subfemtosecond charge oscillation between equivalent Kekulé resonance structures. In this contribution, we show that such dynamical electron-localization in the molecule-fixed frame contravenes the principle of the indistinguishability of identical particles. Read More

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http://dx.doi.org/10.1039/c9cp06794aDOI Listing

The Reaction of β,γ-Epoxy Alcohols with Titanium(III) Reagents. A Proposed Role for Intramolecular Hydrogen Bonding.

Tetrahedron 2019 Nov 1;75(45). Epub 2019 Oct 1.

Department of Chemistry and Biochemistry, The Ohio State University, 100 West 18th Avenue, Columbus, OH 43210 USA.

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http://dx.doi.org/10.1016/j.tet.2019.130662DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7322769PMC
November 2019

Tetracenomycin X inhibits translation by binding within the ribosomal exit tunnel.

Nat Chem Biol 2020 Jun 29. Epub 2020 Jun 29.

Center of Life Sciences, Skolkovo Institute of Science and Technology, Skolkovo, Russia.

The increase in multi-drug resistant pathogenic bacteria is making our current arsenal of clinically used antibiotics obsolete, highlighting the urgent need for new lead compounds with distinct target binding sites to avoid cross-resistance. Here we report that the aromatic polyketide antibiotic tetracenomycin (TcmX) is a potent inhibitor of protein synthesis, and does not induce DNA damage as previously thought. Despite the structural similarity to the well-known translation inhibitor tetracycline, we show that TcmX does not interact with the small ribosomal subunit, but rather binds to the large subunit, within the polypeptide exit tunnel. Read More

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http://dx.doi.org/10.1038/s41589-020-0578-xDOI Listing

NH formation from N and H mediated by molecular tri-iron complexes.

Nat Chem 2020 Jun 29. Epub 2020 Jun 29.

Technische Universität Braunschweig, Institut für Anorganische und Analytische Chemie, Braunschweig, Germany.

Living systems carry out the reduction of N to ammonia (NH) through a series of protonation and electron transfer steps under ambient conditions using the enzyme nitrogenase. In the chemical industry, the Haber-Bosch process hydrogenates N but requires high temperatures and pressures. Both processes rely on iron-based catalysts, but molecular iron complexes that promote the formation of NH on addition of H to N have remained difficult to devise. Read More

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http://dx.doi.org/10.1038/s41557-020-0483-7DOI Listing

The Advanced Floating Chirality Distance Geometry Approach-How Anisotropic NMR Parameters Can Support the Determination of the Relative Configuration of Natural Products.

Mar Drugs 2020 Jun 24;18(6). Epub 2020 Jun 24.

Clemens-Schöpf-Institut für Organische Chemie und Biochemie, Technische Universität Darmstadt, Alarich-Weiss-Straße 4, 64287 Darmstadt, Germany.

The configurational analysis of complex natural products by NMR spectroscopy is still a challenging task. The assignment of the relative configuration is usually carried out by analysis of interproton distances from NOESY or ROESY spectra (qualitative or quantitative) and scalar () couplings. About 15 years ago, residual dipolar couplings (RDCs) were introduced as a tool for the configurational determination of small organic molecules. Read More

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http://dx.doi.org/10.3390/md18060330DOI Listing

Formation and properties of inorganic Si-contaminant compounds.

Environ Pollut 2020 Jun 19;265(Pt B):115032. Epub 2020 Jun 19.

Fachgebiet Bodenchemie mit Pedologie, Institut für Bodenkunde und Standortslehre, Universität Hohenheim, 70593, Stuttgart, Germany.

Soil contamination with inorganic contaminants such as lead (Pb), copper (Cu) and cadmium (Cd) is a major environmental issue. Silicon (Si) may reduce the mobility of the contaminants in the environment so that we studied the extent and the mechanisms of the interactions between Pb, Cd and Cu and silicic acid during its polymerization. We used tetraethyl orthosilicate as Si source and separately Pb(NO), Cd(NO) or Cu(NO). Read More

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http://dx.doi.org/10.1016/j.envpol.2020.115032DOI Listing

Efficient Chemoenzymatic Synthesis of N-Glycans with a β1,4-Galactosylated Bisecting-GlcNAc Motif.

Chembiochem 2020 Jun 28. Epub 2020 Jun 28.

Universität Bayreuth, Bioorganische Chemie, Gebäude NWI, 95440, Bayreuth, GERMANY.

In human serum immunoglobulin G (IgG) a rare modification of biantennary complex N-glycans leads to a  b 1,4-galactosylated bisecting-GlcNAc branch. We found that the bisecting-GlcNAc on a biantennary core-fucosylated N-glycan was enzymatically galactosylated under stringent reaction conditions. Further optimizations led to an efficient enzymatic approach to this particular modification for biantennary substrates. Read More

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http://dx.doi.org/10.1002/cbic.202000268DOI Listing

Toward artificial mussel-glue proteins: Differentiating sequence modules for adhesion and switchable cohesion.

Angew Chem Int Ed Engl 2020 Jun 28. Epub 2020 Jun 28.

Humboldt-University Berlin, Laboratory of Organic Synthesis of Functional System, Department of Chemistry R, Brook-Taylor-Str. 2, 12489, Berlin, GERMANY.

The synthesis of artificial mussel-glue proteins with pH triggered cohesion control mechanism is described by extending the tyrosinase activated polymerization of peptides to sequences having specific modules for cohesion control. The high propensity of those sequence sections to adapt β-sheets is temporarily suppressed by switch defects. This allows enzymatic activation and polymerization to proceed undisturbed. Read More

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http://dx.doi.org/10.1002/anie.202008515DOI Listing

Insights into Ruthenium(II/IV)-Catalyzed Distal C-H Oxygenation by Weak Coordination.

Chemistry 2020 Jun 29. Epub 2020 Jun 29.

Georg-August-Universitaet Goettingen, Institut fuer Organische und Biomolekulare Chemie, Tammannstr. 2, 37077, Goettingen, GERMANY.

C-H hydroxylation of aryl acetamides and alkyl phenylacetyl esters was accomplished via challenging distal weak O -coordination by versatile ruthenium(II/IV) catalysis. The ruthenium(II)-catalyzed C-H oxygenation of aryl acetamides proceeded through C-H activation, ruthenium(II/IV) oxidation and reductive elimination, thus providing step-economical access to valuable phenols. The p -cymene-ruthenium(II/IV) manifold was established by detailed experimental and DFT-computational studies. Read More

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http://dx.doi.org/10.1002/chem.202003062DOI Listing

An α2,3-sialyltransferase from Photobacterium phosphoreum with broad substrate scope: Controlling hydrolytic activity by directed evolution.

Chemistry 2020 Jun 29. Epub 2020 Jun 29.

Technische Universitat Darmstadt, Institut für Organische Chemie und Biochemie, GERMANY.

Defined sialoglycoconjugates are important molecular probes to study the role of sialylated glycans in biological systems. We show that the  α 2,3-sialyltransferase from  Photobacterium phosphoreum  JT-ISH-467 (2,3SiaT pph ) tolerates a very broad substrate scope for modifications in the sialic acid part, including bulky amide variation, C5/C9 substitution and C5 stereoinversion. To reduce the enzyme's hydrolytic activity that erodes the product yield, an extensive structure-guided mutagenesis study identified 3 variants that show up to 5 times higher catalytic efficiency for sialyltransfer, up to 10 times lower efficiency for substrate hydrolysis and drastically reduced product hydrolysis. Read More

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http://dx.doi.org/10.1002/chem.202002277DOI Listing

A 3D-polyphenylalanine network inside porous alumina: Synthesis and characterization of an inorganic-organic composite membrane.

Beilstein J Nanotechnol 2020 17;11:938-951. Epub 2020 Jun 17.

Technische Universität Darmstadt, Fachbereich Chemie, Eduard-Zintl-Institut für Anorganische und Physikalische Chemie, Alarich-Weiss Str. 12, 64287 Darmstadt, Germany.

Surface functionalization of porous materials allows for the introduction of additional functionality coupled with high mechanical stability of functionalized inner pores. Herein, we investigate the surface-initiated ring-opening polymerization (SI-ROP) of phenylalanine--carboxyanhydride (PA-NCA) in porous alumina membranes (ALOX-membranes) with respect to different solvent mixtures (tetrahydrofuran (THF) and dichloromethane (DCM)). It was found that increasing the volume fraction of DCM leads to an increasing amount of fibrillar polymer structures within the porous ALOX-membrane. Read More

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http://dx.doi.org/10.3762/bjnano.11.78DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7308615PMC

Synthesis, structure and anti-cancer activity of osmium complexes bearing π-bound arene substituents and phosphane Co-Ligands: A review.

Eur J Med Chem 2020 May 28;201:112483. Epub 2020 May 28.

Maastricht Science Programme, Faculty of Science and Engineering, Maastricht University, Kapoenstraat 2, PO Box 616, 6200, MD, Maastricht, the Netherlands. Electronic address:

While many examples of osmium complexes, as anti-cancer agents, have been reported and some reviews have been devoted to this topic, a particularly interesting and synthetically accessible sub-class of these compounds namely those bearing a π- bound arene and phosphane co-ligand have escaped review. These complexes have made a surprisingly late entry in the literature (2005) in terms of anti-cancer investigations. This is somewhat surprising considering the plethora of analogous complexes that have been reported for the lighter analogue, ruthenium. Read More

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http://dx.doi.org/10.1016/j.ejmech.2020.112483DOI Listing

Diradical organic one-dimensional polymers synthesized on a metallic surface.

Angew Chem Int Ed Engl 2020 Jun 27. Epub 2020 Jun 27.

Instituto Madrileno de Estudios Avanzados, Nanoarchitectures at Surfaces, SPAIN.

The synthesis of radical polymers with control over chemical composition and structure is a milestone in materials science and has re-emerged recently because of the development of new synthetic methods to produce stable radical organic compounds. However, their synthesis is remarkably challenging due to the inherent reactivity induced by the presence of unpaired electrons in their structure. Here, we report on the synthesis and characterization of atomically precise one-dimensional diradical peripentacene polymers on a Au(111) surface. Read More

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http://dx.doi.org/10.1002/anie.202006276DOI Listing

Antiproliferative Activity of Functionalized Histidine derived Au(I) bis-NHC Complexes for Bioconjugation.

Chem Asian J 2020 Jun 27. Epub 2020 Jun 27.

Technische Universität München, Department of Chemistry, Lichtenbergstr. 4, 85747, Garching bei München, GERMANY.

A series of histidine derived Au(I) bis -NHC complexes bearing different ester, amide and carboxylic acid functionalities as well as wingtip substituents is synthesized and characterized. The stability in aqueous media, in vitro cytotoxicity in a set of cancer cell lines (MCF7, PC3 and A2780/A2780cisR) along with the cellular uptake are evaluated. Stability tests suggest hydrolysis of the ester within 8 h, which might lead to deactivation. Read More

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http://dx.doi.org/10.1002/asia.202000620DOI Listing

Understanding the interaction of polyelectrolyte architectures with proteins and biosystems.

Angew Chem Int Ed Engl 2020 Jun 26. Epub 2020 Jun 26.

McGill University, Pharmacology and Therapeutics, GERMANY.

Polyelectrolytes such as e.g. DNA or heparin are long linear or branched macromolecules onto which charges are appended. Read More

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http://dx.doi.org/10.1002/anie.202006457DOI Listing