4,370,073 results match your criteria Chemistry & biology[Journal]


Using Artificial Intelligence to Identify Factors Associated with Autism Spectrum Disorder in Adolescents with Cerebral Palsy.

Neuropediatrics 2019 Apr 24. Epub 2019 Apr 24.

Department of Pediatric Orthopaedic Surgery, Lenval University Pediatric Hospital of Nice, Nice, France.

Autism spectrum disorder (ASD) is common in adolescents with cerebral palsy (CP) and there is a lack of studies applying artificial intelligence to investigate this field and this population in particular. The aim of this study is to develop and test a predictive learning model to identify factors associated with ASD in adolescents with CP. This was a multicenter controlled cohort study of 102 adolescents with CP (61 males, 41 females; mean age ± SD [standard deviation] = 16. Read More

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http://dx.doi.org/10.1055/s-0039-1685525DOI Listing

Platelet Activation by Antiphospholipid Antibodies Depends on Epitope Specificity and is Prevented by mTOR Inhibitors.

Thromb Haemost 2019 Apr 24. Epub 2019 Apr 24.

Institute of Clinical Chemistry and Laboratory Medicine, University Medical Center Mainz, Mainz, Germany.

Antiphospholipid antibodies (aPL) have been reported to activate platelets. This is considered to be one of the pathogenic properties of aPL. Even though aPL heterogeneity is quite well established, little is known, if the ability to activate platelets is common to all aPL or depends on antigen specificity. Read More

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http://dx.doi.org/10.1055/s-0039-1685453DOI Listing

Schiff-base reaction induced selective sensing of trace dopamine based on Pt41Rh59 alloy/ZIF-90 nanocomposite.

Nanotechnology 2019 Apr 24. Epub 2019 Apr 24.

Department of Physics, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, HONG KONG.

Zeolitic imidazole frameworks (ZIFs) are a new class of functional porous materials with attractive characters, such as gas storage, selective separation, catalysis, and drug delivery. We report herein using nanoscale ZIF-90 crystals with free aldehyde group of imidazole-2-carboxaldehyde (ICA) ligand for the selective electrochemical detection of dopamine. The averaged adsorption enthalpy ΔH (i. Read More

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http://dx.doi.org/10.1088/1361-6528/ab1bfbDOI Listing

Implications of the mitochondrial interactome of mammalian thioredoxin 2 for normal cellular function and disease.

Free Radic Biol Med 2019 Apr 21. Epub 2019 Apr 21.

Department of Chemistry, University of Patras, Rion 26504, Greece. Electronic address:

Multiple thioredoxin isoforms exist in all living cells. To explore the possible functions of mammalian mitochondrial thioredoxin 2 (Trx2), an interactome of mouse Trx2 was initially created using (i) a monothiol mouse Trx2 species for capturing protein partners from different organs and (ii) yeast two hybrid screens on human liver and rat brain cDNA libraries. The resulting interactome consisted of 195 proteins (Trx2 included) plus the mitochondrial 16S RNA. Read More

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http://dx.doi.org/10.1016/j.freeradbiomed.2019.04.018DOI Listing

Chemical composition and cytotoxic screening of Musa cavendish green peels extract: Antiproliferative activity by activation of different cellular death types.

Toxicol In Vitro 2019 Apr 21. Epub 2019 Apr 21.

Emergency Medicine Department, Medical School, University of São Paulo, Av. Dr. Arnaldo, 455 - Cerqueira César, São Paulo, São Paulo CEP 01246-903, Brazil.

Musa cavendish, commonly known as banana, is a fruit with nutritional and therapeutic properties. We investigated the chemical composition and in vitro cytotoxic effect of M. cavendish green peel extract (MHE) on cancer cells for the first time. Read More

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http://dx.doi.org/10.1016/j.tiv.2019.04.020DOI Listing

Modeling Glycan Processing Reveals Golgi-Enzyme Homeostasis upon Trafficking Defects and Cellular Differentiation.

Cell Rep 2019 Apr;27(4):1231-1243.e6

Department of Biology, University of York, York YO10 5DD, UK. Electronic address:

The decoration of proteins by carbohydrates is essential for eukaryotic life yet heterogeneous due to a lack of biosynthetic templates. This complex carbohydrate mixture-the glycan profile-is generated in the compartmentalized Golgi, in which level and localization of glycosylation enzymes are key determinants. Here, we develop and validate a computational model for glycan biosynthesis to probe how the biosynthetic machinery creates different glycan profiles. Read More

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https://linkinghub.elsevier.com/retrieve/pii/S22111247193045
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http://dx.doi.org/10.1016/j.celrep.2019.03.107DOI Listing
April 2019
1 Read

Small-Molecule-Based Fluorescent Sensors for Selective Detection of Reactive Oxygen Species in Biological Systems.

Annu Rev Biochem 2019 Apr 24. Epub 2019 Apr 24.

Morningside Laboratory for Chemical Biology, Department of Chemistry, The University of Hong Kong, Hong Kong, P. R. China; email: , , , ,

Reactive oxygen species (ROS) encompass a collection of intricately linked chemical entities characterized by individually distinct physicochemical properties and biological reactivities. Although excessive ROS generation is well known to underpin disease development, it has become increasingly evident that ROS also play central roles in redox regulation and normal physiology. A major challenge in uncovering the relevant biological mechanisms and deconvoluting the apparently paradoxical roles of distinct ROS in human health and disease lies in the selective and sensitive detection of these transient species in the complex biological milieu. Read More

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http://dx.doi.org/10.1146/annurev-biochem-013118-111754DOI Listing

Single Nanoparticle Electrochemistry.

Annu Rev Anal Chem (Palo Alto Calif) 2019 Apr 24. Epub 2019 Apr 24.

School of Chemistry and Molecular Engineering, East China University of Science and Technology, Shanghai 200237, China; email: ;

Experimental techniques to monitor and visualize the behaviors of single nanoparticles have not only revealed the significant spatial and temporal heterogeneity of those individuals, which are hidden in ensemble methods, but more importantly, they have also enabled researchers to elucidate the origin of such heterogeneity. In pursuing the intrinsic structure-function relations of single nanoparticles, the recently developed stochastic collision approach demonstrated some early promises. However, it was later realized that the appropriate sizing of a single nanoparticle by an electrochemical method could be far more challenging than initially expected owing to the dynamic motion of nanoparticles in electrolytes and complex charge-transfer characteristics at electrode surfaces. Read More

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http://dx.doi.org/10.1146/annurev-anchem-061318-114902DOI Listing

Advances in the Use of Microfluidics to Study Crystallization Fundamentals.

Annu Rev Chem Biomol Eng 2019 Apr 24. Epub 2019 Apr 24.

Aix-Marseille Université, CNRS, CINaM UMR 7325, 13288 Marseille, France; email: , , ,

This review compares droplet-based microfluidic systems used to study crystallization fundamentals in chemistry and biology. An original high-throughput droplet-based microfluidic platform is presented. It uses nanoliter droplets, generates a chemical library, and directly solubilizes powder, thus economizing both material and time. Read More

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http://dx.doi.org/10.1146/annurev-chembioeng-060718-030312DOI Listing

Formulation and characterization of conjugate vaccines to reduce opioid use disorders suitable for pharmaceutical manufacturing and clinical evaluation.

Mol Pharm 2019 Apr 24. Epub 2019 Apr 24.

This study focused on formulating conjugate vaccines targeting oxycodone and heroin for technology transfer, Good Manufacturing Process (GMP), and clinical evaluation. Lead vaccines used the highly immunogenic carrier protein keyhole limpet hemocyanin (KLH), which poses formulation problems because of its size. To address this barrier to translation, an oxycodone-based hapten conjugated to GMP-grade subunit KLH (OXY-sKLH) and adsorbed on alum adjuvant was studied with regard to carbodiimide coupling reaction time, buffer composition, purification methods for conjugates, conjugate size, state of aggregation, and protein:alum ratio. Read More

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http://dx.doi.org/10.1021/acs.molpharmaceut.8b01296DOI Listing

Heterointerface-Driven Band Alignment Engineering and its Impact on Macro-Performance in Semiconductor Multilayer Nanostructures.

Small 2019 Apr 24:e1900837. Epub 2019 Apr 24.

Laboratory of Advanced Materials, Department of Materials Science, Collaborative Innovation Center of Chemistry for Energy Materials, Fudan University, Shanghai, 200438, P. R. China.

Interfaces in semiconductor heterostructures is of continuously greater significance in the trend of scaling materials down to the atomic limit. Since atoms tend to behave more irregularly around interfaces than in internal materials, accurate energy band alignment becomes a major challenge, which determines the ultimate performance of devices. Therefore, a comprehensive understanding of the interplay between heterointerface, energy band, and macro-performance is desiderated. Read More

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https://onlinelibrary.wiley.com/doi/abs/10.1002/smll.2019008
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http://dx.doi.org/10.1002/smll.201900837DOI Listing
April 2019
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A guide to hyaluronan and related enzymes in breast cancer: biological significance and diagnostic value.

FEBS J 2019 Apr 24. Epub 2019 Apr 24.

Biochemistry, Biochemical Analysis& Matrix Pathobiochemistry Research Group, Department of Chemistry, University of Patras, 26504, Patras, Greece.

Hyaluronan is a unique non-sulfated glycosaminoglycan that contributes to breast cancer cells growth and functional properties, including cell migration, invasion, adhesion, as well as tumor-associated angiogenesis in different stages of breast cancer progression and especially metastasis. Latest data show that the levels of hyaluronan and/or low molecular mass hyaluronan in blood serum and plasma of breast cancer patients may be a useful biomarker for breast cancer prognosis, differential diagnosis and patients' treatment monitoring. Therefore, the qualitative and quantitative determination of hyaluronan in biological samples is an emerging area of research. Read More

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http://dx.doi.org/10.1111/febs.14860DOI Listing
April 2019
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Bioinspired Multivalent Peptide Nanotubes for Sialic Acid Targeting and Imaging-Guided Treatment of Metastatic Melanoma.

Small 2019 Apr 24:e1900157. Epub 2019 Apr 24.

School of Chemistry and Molecular Engineering, East China Normal University, Shanghai, 200241, China.

Tumor metastasis is considered a major cause of cancer-related human mortalities. However, it still remains a formidable challenge in clinics. Herein, a bioinspired multivalent nanoplatform for the highly effective treatment of the metastatic melanoma is reported. Read More

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https://onlinelibrary.wiley.com/doi/abs/10.1002/smll.2019001
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http://dx.doi.org/10.1002/smll.201900157DOI Listing
April 2019
1 Read

Cocoa Shell Aqueous Phenolic Extract Preserves Mitochondrial Function and Insulin Sensitivity by Attenuating Inflammation Between Macrophages and Adipocytes in vitro.

Mol Nutr Food Res 2019 Apr 24:e1801413. Epub 2019 Apr 24.

M. Rebollo-Hernanz, Q. Zhang, E. G. de Mejia, Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, IL, 61801, United States.

Scope: The aim was to assess the action of an aqueous extract from cocoa shell (CAE) and its main phenolic compounds to prevent the loss of obesity-induced mitochondrial function and insulin sensitivity, targeting inflammation between macrophages-adipocytes in vitro.

Methods And Results: CAE (31-500 μg mL ) inhibited 3T3-L1 adipocytes lipid accumulation and induced browning during differentiation. LPS-stimulated RAW264. Read More

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http://dx.doi.org/10.1002/mnfr.201801413DOI Listing

Ultrathin 2D Rare-Earth Nanomaterials: Compositions, Syntheses, and Applications.

Adv Mater 2019 Apr 24:e1806461. Epub 2019 Apr 24.

Tianjin Key Lab for Rare Earth Materials and Applications, Center for Rare Earth and Inorganic Functional Materials, School of Materials Science and Engineering, National Institute for Advanced Materials, Nankai University, Tianjin, 300350, P. R. China.

Ultrathin 2D nanomaterials possess promising properties due to electron confinement within single or a few atom layers. As an emerging class of functional materials, ultrathin 2D rare-earth nanomaterials may incorporate the unique optical, magnetic, and catalytic behaviors of rare-earth elements into layers, exhibiting great potential in various applications such as optoelectronics, magnetic devices, transistors, high-efficiency catalysts, etc. Despite its importance, reviews on ultrathin 2D rare-earth nanomaterials or related topics are rare and only focus on a certain family of ultrathin 2D rare-earth nanomaterials. Read More

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http://dx.doi.org/10.1002/adma.201806461DOI Listing

Selective SN2 ring opening / C-C coupling of vinyl epoxides and styrene oxide with diborylmethide lithium salts.

Chemistry 2019 Apr 24. Epub 2019 Apr 24.

SPAIN.

Vinyl epoxides and styrene oxide can react with diborylmethide lithium salts throughout an exclusive SN2 borylmethylation / ring opening in a regio- and diastereoselctive way, depending on the nature of the substrate. The ring opening protocol provides homoallylboronates that can be transformed into challenging diastereomeric bishomoallylic alicyclic 1,3-diols. Eventually, unprecedented 3-borylated 1,2-oxaborolan-2-ol products are prepared by borylmethylation / ring opening of 2-methyl-2-vinyloxirane followed by intramolecular cyclization. Read More

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http://dx.doi.org/10.1002/chem.201901406DOI Listing

Phytochemical analysis of Vietnamese propolis produced by the stingless bee Lisotrigona cacciae.

PLoS One 2019 24;14(4):e0216074. Epub 2019 Apr 24.

Institute of Organic Chemistry with Centre of Phytochemistry, Bulgarian Academy of Sciences, Sofia, Bulgaria.

Propolis produced by the stingless bee Lisotrigona cacciae was studied for the first time. Using different chromatographic procedures, a total of eighteen constituents (phenols and triterpenes) were isolated, among which flavane 1, homoisoflavanes 2-4, and xanthones 5 and 6 were new for propolis. Propolis extract was also characterized by gas chromatography/mass spectrometry and other fifteen constituents were identified. Read More

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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0216074PLOS

Narciclasine exerts anti-inflammatory actions by blocking leukocyte-endothelial cell interactions and down-regulation of the endothelial TNF receptor 1.

FASEB J 2019 Apr 24:fj201802440R. Epub 2019 Apr 24.

Institute of Pharmaceutical Biology, Faculty of Biochemistry, Chemistry and Pharmacy, Goethe University Frankfurt, Frankfurt, Germany.

The alkaloid narciclasine has been characterized extensively as an anticancer compound. Accumulating evidence suggests that narciclasine has anti-inflammatory potential; however, the underlying mechanism remains poorly understood. We hypothesized that narciclasine affects the activation of endothelial cells (ECs), a hallmark of inflammatory processes, which is a prerequisite for leukocyte-EC interaction. Read More

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http://dx.doi.org/10.1096/fj.201802440RDOI Listing

A General TR-FRET Assay Platform for High-Throughput Screening and Characterizing Inhibitors of Methyl-Lysine Reader Proteins.

SLAS Discov 2019 Apr 24:2472555219844569. Epub 2019 Apr 24.

2 Center for Integrative Chemical Biology and Drug Discovery, Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.

Chromatin regulatory complexes localize to specific sites via recognition of posttranslational modifications (PTMs) on N-terminal tails of histone proteins (e.g., methylation, acetylation, and phosphorylation). Read More

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http://dx.doi.org/10.1177/2472555219844569DOI Listing

Matrix stiffness regulates microvesicle-induced fibroblast activation.

Am J Physiol Cell Physiol 2019 Apr 24. Epub 2019 Apr 24.

Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, United States.

Extracellular vesicles released by cancer cells have recently been implicated in the differentiation of stromal cells to their activated, cancer-supporting states. Microvesicles, a subset of extracellular vesicles released from the plasma membrane of cancer cells, contain biologically active cargo, including DNA, mRNA, and miRNA, which are transferred to recipient cells and induce a phenotypic change in behavior. While it is known that microvesicles can alter recipient cell phenotype, little is known about how the physical properties of the tumor microenvironment affect fibroblast response to microvesicles. Read More

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http://dx.doi.org/10.1152/ajpcell.00418.2018DOI Listing
April 2019
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Chemoselective Borono-Catellani Arylation for Unsymmetrical Biaryls Synthesis.

Org Lett 2019 Apr 24. Epub 2019 Apr 24.

Sauvage Center for Molecular Sciences, College of Chemistry and Molecular Sciences , Wuhan University , 430072 Wuhan , China.

Reported is the borono-Catellani arylation process for unsymmetrical biaryls synthesis, utilizing the readily available pinacol ester of arylboronic acids, aryl bromides, and olefins as the reactants. The distinct reactivity of arylboronic ester and aryl bromides secures the excellent chemoselectivity in the pivotal arylation step. The reaction is enabled by the cooperative catalysis of Pd(OAc) and the NBE derivative N, with molecular oxygen as the terminal oxidant. Read More

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http://dx.doi.org/10.1021/acs.orglett.9b01072DOI Listing

Pd-Catalyzed Decarboxylative Ortho-Halogenation of Aryl Carboxylic Acids with Sodium Halide NaX Using Carboxyl as a Traceless Directing Group.

Org Lett 2019 Apr 24. Epub 2019 Apr 24.

College of Chemistry , Nanchang University , Nanchang , Jiangxi 330031 , China.

A highly regioselective Pd-catalyzed carboxyl directed decarboxylative ortho-C-H halogenation of cheap o-nitrobenzoic acids with NaX (X = I, Br) under aerobic conditions has been established. The utility of the method has been demonstrated by the gram-scale reaction and derivatization of the product. Experimental results have confirmed Pd and Bi played critical roles in the transformation and indicated the transformation might proceed via 2-halo-6-nitrobenzoic acid derivative intermediate. Read More

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http://dx.doi.org/10.1021/acs.orglett.9b00460DOI Listing
April 2019
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Chemoselective Synthesis of N-Terminal Cysteinyl Thioesters via β,γ-C,S Thiol-Michael Addition.

Org Lett 2019 Apr 24. Epub 2019 Apr 24.

School of Chemistry and Trinity Biomedical Sciences Institute (TBSI) , Trinity College Dublin, The University of Dublin , Dublin 2 , Ireland.

Dehydroalanine (ΔAla) is a highly electrophilic residue that can react efficiently with sulfur nucleophiles to furnish cysteinyl analogues. Herein, we report an efficient synthesis of N-terminal cysteinyl thioesters, suitable for S, N-acyl transfer, based on β,γ-C,S thiol-Michael addition. Both ionic and radical-based methodologies were found to be efficient for this process. Read More

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http://dx.doi.org/10.1021/acs.orglett.9b01013DOI Listing

Halogenated Tyrosine Derivatives from the Tropical Eastern Pacific Zoantharians Antipathozoanthus hickmani and Parazoanthus darwini.

J Nat Prod 2019 Apr 24. Epub 2019 Apr 24.

Marine Biodiscovery, School of Chemistry and Ryan Institute , National University of Ireland Galway (NUI Galway) , University Road , H91 TK33 Galway , Ireland.

In the search for bioactive marine natural products from zoantharians of the Tropical Eastern Pacific, four new tyrosine dipeptides, named valdiviamides A-D (1-4), were isolated from Antipathozoanthus hickmani, and two new tyramine derivatives, 5 and 6, from Parazoanthus darwini. The phenols of all six tyrosine derivatives are substituted by bromine and/or iodine atoms at the ortho positions of the hydroxyl. The planar structures of these aromatic alkaloids were elucidated from 1D and 2D NMR experiments in combination with HRESIMS data, and the absolute configurations of 1-4 were deduced from comparison between experimental and calculated electronic circular dichroism spectra. Read More

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http://dx.doi.org/10.1021/acs.jnatprod.9b00173DOI Listing

Leucinostatin Y: A Peptaibiotic Produced by the Entomoparasitic Fungus Purpureocillium lilacinum 40-H-28.

J Nat Prod 2019 Apr 24. Epub 2019 Apr 24.

Institute of Microbial Chemistry (BIKAKEN) , Numazu, 18-24 Miyamoto , Numazu-shi , Shizuoka 410-0301 , Japan.

Leucinostatin Y, a new peptaibiotic, was isolated from the culture broth of the entomoparasitic fungus Purpureocillium lilacinum 40-H-28. The planar structure was elucidated by detailed analysis of its NMR and MS/MS data. The absolute configurations of the amino acids were partially determined by an advanced Marfey's method. Read More

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http://dx.doi.org/10.1021/acs.jnatprod.8b00839DOI Listing

The Mosaic of Rottlerin: The Sequel.

J Nat Prod 2019 Apr 24. Epub 2019 Apr 24.

School of Chemistry , UNSW Australia , Sydney , NSW 2052 , Australia.

Rottlerin (1) is a potent protein kinase C δ inhibitor that possesses a wide range of biological activities. However, the potential of this molecule to be developed as a drug has been restricted by its limited availability. We report herein a gram scale quantity synthesis of rottlerin in a five-step synthetic route that can be completed within 2 days. Read More

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http://dx.doi.org/10.1021/acs.jnatprod.8b00917DOI Listing
April 2019
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Temperature-Dependent Rate Coefficient for the Reaction of CHSH with the Simplest Criegee Intermediate.

J Phys Chem A 2019 Apr 24. Epub 2019 Apr 24.

The kinetics of the reaction of the simplest Criegee intermediate CHOO with CHSH was measured with transient IR absorption spectroscopy in a temperature-controlled flow reaction cell, and the bimolecular rate coefficients were measured from 278 to 349 K and at total pressure from 10 to 300 Torr. The measured bimolecular rate coefficient at 298 K and 300 Torr is (1.01 ± 0. Read More

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http://dx.doi.org/10.1021/acs.jpca.8b12553DOI Listing

Key Aroma Compounds in Oats and Oat Cereals.

J Agric Food Chem 2019 Apr 24. Epub 2019 Apr 24.

Department of Food Science and Technology , Oregon State University , 100 Wiegand Hall , Corvallis , Oregon 97331-6602 , United States.

Oats possess a unique flavor, comprising grain and nut-like sensory characteristics. The first comprehensive study of oat flavor by Heydanek and McGorrin [ Heydanek , M. G. Read More

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http://dx.doi.org/10.1021/acs.jafc.9b00994DOI Listing

Aligning product chemistry and soil context for agronomic reuse of human-derived resources.

Environ Sci Technol 2019 Apr 24. Epub 2019 Apr 24.

Recovering human-derived nutrients from sanitation systems can offset inorganic fertilizer use and improve access to agricultural nutrients in resource-limited settings, but the agronomic value of recovered products depends upon product chemistry and soil context. Products may exacerbate already-compromised soil conditions, offer benefits beyond nutrients, or have reduced efficacy depending on soil characteristics. Using global spatial modeling, we evaluate the soil suitability of seven products (wastewater, sludge, compost, urine, ammonium sulfate, ammonium struvite, potassium struvite) and integrate this information with local recovery potential of each product from sanitation systems that will need to be installed to achieve universal coverage (referred to here as "newly-installed sanitation"). Read More

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http://pubs.acs.org/doi/10.1021/acs.est.9b00504
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http://dx.doi.org/10.1021/acs.est.9b00504DOI Listing
April 2019
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Comparing the Ligand Behavior of N-Heterocyclic Phosphenium and Nitrosyl Units in Iron and Chromium Complexes.

Inorg Chem 2019 Apr 24. Epub 2019 Apr 24.

Institute for Inorganic Chemistry , University of Stuttgart , Pfaffenwaldring 55 , 70550 Stuttgart , Germany.

N-Heterocyclic phosphenium (NHP) and nitrosonium (NO) ligands are often viewed as isolobal analogues that share the capability to switch between different charge states and thus display redox "noninnocent" behavior. We report here on mixed complexes [(NHP)M(CO) (NO)] (M = Fe, Cr; n = 2, 3), which permit evaluating the donor/acceptor properties of both types of ligands and their interplay in a single complex. The crystalline target compounds were obtained from reactions of N-heterocyclic phosphenium triflates with PPN[Fe(CO)(NO)] or PPN[Cr(CO)(NO)], respectively, and fully characterized (PPN = nitride-bistriphenylphosphonium cation). Read More

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http://dx.doi.org/10.1021/acs.inorgchem.9b00737DOI Listing

Synthesis, Crystal Structures, and Photochemical Properties of a Family of Heterometallic Titanium Oxo Clusters.

Inorg Chem 2019 Apr 24. Epub 2019 Apr 24.

State Key Laboratory of Rare Earth Resource Utilization , Changchun Institute of Applied Chemistry, Chinese Academy of Sciences , 5625 Renmin Street , Changchun , Jilin 130022 , China.

The incorporation of heterometallic atoms into the structure of titanium-oxygen nanomaterials is one of the known and effective strategies to develop new high-performance photovoltaic active materials. In this study, we have synthesized three benzoic acid-stabilized heterometallic titanium oxo clusters with the different transition metals Co, Cu, and Cd, formulated as [TiCo(μ-O)(μ-O)(CHCOO)(CHCN)]·2CHCN (1), [TiCu(μ-O)(CHCOO)] (2), and [TiCd(μ-O)(μ-O)(μ-O)(CHCOO)(CHCOOH)(CHCN)]·CHCN·CHCOOH (3), and then we characterized their structures. UV-vis spectroscopy analysis revealed an enhanced UV-vis-light absorption of those heterometallic clusters. Read More

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http://dx.doi.org/10.1021/acs.inorgchem.9b00508DOI Listing

Probing Size and Substrate Effects on the Hydrogen Evolution Reaction by Single Isolated Pt Atoms, Atomic Clusters, and Nanoparticles.

J Am Chem Soc 2019 Apr 24. Epub 2019 Apr 24.

Center for Electrochemistry, Department of Chemistry , The University of Texas at Austin , Austin , Texas 78712 , United States.

We report the catalytic activity of a single, isolated Pt deposit on Bi and Pb supports to probe the size and substrate effects on the electrochemical hydrogen evolution reaction (HER). Deposits were made electrolytically by an atom-by-atom method in a controlled plating; we prepared an individual Pt deposit on Bi and Pb ultramicroelectrodes (UMEs) such as a single isolated atom, clusters containing one to five Pt atoms, and nanoparticles to about 10 nm radius. A steady-state voltammogram on the single Pt deposits is observed by electrocatalytic amplification of the HER, with a negligible contribution by the HER at the substrate UME. Read More

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http://dx.doi.org/10.1021/jacs.8b13366DOI Listing

CO and CO/H Conversion to Methoxide by a Uranium(IV) Hydride.

J Am Chem Soc 2019 Apr 24. Epub 2019 Apr 24.

Institut des Sciences et Ingénierie Chimiques , Ecole Polytechnique Fédérale de Lausanne (EPFL) , CH-1015 Lausanne , Switzerland.

Here we show that a scaffold combining siloxide ligands and a bridging oxide allows the synthesis and characterization of the stable dinuclear uranium(IV) hydride complex [K{[U(OSi(O Bu))](μ-O)(μ-H)}], 2, which displays high reductive reactivity. The dinuclear bis-hydride 2 effects the reductive coupling of acetonitrile by hydride transfer to yield [K{[U(OSi(O Bu))](μ-O)(μ-κ-NC(CH)NCHCH)}], 3. Under ambient conditions, the reaction of 2 with CO affords the oxomethylene reduction product [K{[U(OSi(O Bu))](μ-CHO)(μ-O)}], 4, that can further add H to afford the methoxide hydride complex [K{[U(OSi(O Bu))](μ-OCH)(μ-O)(μ-H)}], 5, from which methanol is released in water. Read More

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http://dx.doi.org/10.1021/jacs.9b02235DOI Listing

11/15/17 Complexes as Molecular Models for Metal Halide Double Perovskite Materials.

Inorg Chem 2019 Apr 24. Epub 2019 Apr 24.

Department of Chemistry and Material Sciences Center , Philipps-Universität Marburg , Hans-Meerwein-Straße , 35043 Marburg , Germany.

Thirteen neutral complexes [E M X (PPh) (L) ] (E = Bi, Sb; M = Cu, Ag; X = Cl, Br, I; L = solvent) featuring three different motifs were prepared and characterized regarding their structure, stability, and absorption spectra. While not identical in structural motif, the compounds can serve as models for the influence of the composition E/M/X on the optical properties of double perovskites AEMX (A = Cs, CHNH). Read More

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http://pubs.acs.org/doi/10.1021/acs.inorgchem.9b00429
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http://dx.doi.org/10.1021/acs.inorgchem.9b00429DOI Listing
April 2019
1 Read

A Kinetic Model of Oligonucleotide-Brush Interactions for the Rational Design of Gene Delivery Vectors.

Biomacromolecules 2019 Apr 24. Epub 2019 Apr 24.

Polymer brushes are attractive candidates for the design of gene delivery vectors as they allow the systematic study of the impact of structural (type, size and shape of nanomaterials core) and physico-chemical parameters (cationic monomer chemistry, brush thickness and grafting density) on transfection efficiency. However, relatively little is known of their interactions of oligonucleotides. To study such interactions, we use surface plasmon resonance and developed a kinetic model of brush binding and infiltration. Read More

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http://dx.doi.org/10.1021/acs.biomac.9b00155DOI Listing

Interfacial vs Bulk Ozonolysis of Nerolidol.

Environ Sci Technol 2019 Apr 24. Epub 2019 Apr 24.

Ozone readily reacts with olefins with the formation of more reactive Criegee intermediates (CIs). The transient Criegee intermediates impact HOx cycles and they play a role in new particle formation in the troposphere. Oxidation by O3 occurs both in the gas-phase, in the liquid phase, and at air-water and air-aerosol interfaces. Read More

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http://dx.doi.org/10.1021/acs.est.9b00364DOI Listing
April 2019
1 Read

From Molecular and Emulsified Ion Sensors to Membrane Electrodes: Molecular and Mechanistic Sensor Design.

Acc Chem Res 2019 Apr 24. Epub 2019 Apr 24.

University of Geneva , Department of Inorganic and Analytical Chemistry , Quai Ernest Ansermet 30 , Geneva 1211 , Switzerland.

Selective molecular ion probes are often insoluble in water and require a hydrophobic solvent environment for strong and selective binding, which runs counter to the desire of utilizing them in a homogeneous solution. This Account aims to guide the reader on how such molecules, often coined ionophores, can be harnessed to design exceptionally useful optical and electrochemical sensors. We start here with some historical context on the design of such ionophores and continue with the explanation of the response mechanism of optical and potentiometric sensors and the role of combined components to build a robust ion sensor. Read More

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http://dx.doi.org/10.1021/acs.accounts.9b00056DOI Listing
April 2019
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Solid-State Photochromism by Molecular Assembly of Bis-o-Carboranyl Siloles.

Chemistry 2019 Apr 24. Epub 2019 Apr 24.

Korea University, Advanced Materials Chemistry, 2511 Sejong-ro, 30019, Sejong, KOREA, REPUBLIC OF.

A new type of solid-state photochromism was observed in an AB2 type molecular assembly comprising the central silole and two peripheral o-carborane units, and in this assembly, depending on the assembling positions of those units at the adjoining benzene ring, two different regioisomers were formed: Si-m-Cb and Si-p-Cb. Each isomer showed different solid-state photochromism depending on its solid-state conformation and was either in the crystalline or amorphous state. The crystals of each meta- or para-isomer, CSi-m-Cb or CSi-p-Cb, showed yellow or blue emission, and mechanically grinding those crystals into amorphous powders of ASi-m-Cb and ASi-p-Cb, switched their emissions to blue and yellow, respectively. Read More

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http://dx.doi.org/10.1002/chem.201901305DOI Listing

Ion Association in Lanthanide Chloride Solutions.

Chemistry 2019 Apr 24. Epub 2019 Apr 24.

UNITED KINGDOM.

A better understanding of the solution chemistry of the lanthanide (Ln) salts in water would have wide ranging implications in materials processing, waste management, element tracing, medicine and minerals processing - particularly given governmental concerns about Ln security of supply. Despite much effort, even in simple systems, the mechanisms and thermodynamics of Ln(III) association with small anions remain unclear. In the present study, molecular dynamics (MD), using a newly developed force field, provide new insights into LnCl₃(aq) solutions. Read More

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http://dx.doi.org/10.1002/chem.201900945DOI Listing

Nature of halogen-centered intermolecular interactions in crystal growth and design: Fluorine-centered interactions in dimers in crystalline hexafluoropropylene as a prototype.

J Comput Chem 2019 Apr 24. Epub 2019 Apr 24.

Department of Chemical System Engineering, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan.

The wide occurrence of halogen-centered noncovalent interactions in crystal growth and design prompted this study, which includes a mini review of recent advances in the field. Particular emphasis is placed on providing compelling theoretical evidence of the formation of these interactions between sites of positive electrostatic potential, as well as between sites of negative electrostatic potential, localized on the electrostatic surfaces of the bound fluorine atoms in a prototypical system, hexafluoropropylene (C F ), upon its interaction with another same molecule to form (C F ) dimers. The existence of σ- and π-hole interactions is shown for the stable dimers. Read More

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http://dx.doi.org/10.1002/jcc.25836DOI Listing

Observe Spatiotemporal Heterogeneity of Reactions in Solution with High-Speed Single Nanorod Rotational Sensing.

Angew Chem Int Ed Engl 2019 Apr 24. Epub 2019 Apr 24.

Tsinghua University, Department of Chemistry, Department of Chemistry, Tsinghua University, 100084, Beijing, CHINA.

We have developed a high-speed dark-field microscope to monitor the rapid rotation of single gold nanorods (AuNRs) and use it to study the spatiotemporal heterogeneity of chemical reactions in free solution. A wide range of viscosity change from 237 cP to 0.8 cP could be detected conveniently. Read More

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http://dx.doi.org/10.1002/anie.201901550DOI Listing

[Fe(H2O)5(NO)]2+, the 'Brown-Ring' Chromophore.

Angew Chem Int Ed Engl 2019 Apr 24. Epub 2019 Apr 24.

Ludwig-Maximilians-Universitaet, Department of Chemistry, Butenandtstrasse 5-13, Haus D, 81377, München, GERMANY.

Although the 'brown-ring' [Fe(H2O)5(NO)]2+ (1) ion has been a research target for more than a century, this poorly stable species had never been isolated. We now report on the synthesis of crystals of a salt of 1 which allowed us to tackle the unique bonding situation on an experimental basis. As a result of the bonding analysis, two stretched, spin-polarised π-interactions provide the Fe-NO binding - and challenge the concept of 'oxidation state'. Read More

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http://dx.doi.org/10.1002/anie.201902374DOI Listing

The Glycosylation Mechanisms of 6,3-Uronic Acid Lactones.

Angew Chem Int Ed Engl 2019 Apr 24. Epub 2019 Apr 24.

Radboud University, Molecular Chemistry, Heyendaalseweg 135, 6525AJ, Nijmegen, NETHERLANDS.

Uronic acids are important constituents of polysaccharides found on the cell membranes of different organisms. To prepare uronic acid containing oligosaccharides, uronic acid 6,3-lactones can be employed as they display a fixed conformation and a unique reactivity and stereoselectivity. Herein we report a highly β-selective and efficient mannosyl donor based on C-4 acetyl mannuronic acid 6,3-lactone donors. Read More

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http://dx.doi.org/10.1002/anie.201902507DOI Listing

Biochemical and structural characterization of XoxG and XoxJ and their roles in activity of the lanthanide-dependent methanol dehydrogenase, XoxF.

Chembiochem 2019 Apr 24. Epub 2019 Apr 24.

Pennsylvania State University, Chemistry, 220 Chemistry Building, Penn State University, 16802, University Park, UNITED STATES.

Lanthanide (Ln)-dependent methanol dehydrogenases (MDHs) have been recently shown to be widespread in methylotrophic bacteria. Along with the core MDH protein, XoxF, these systems comprise two other proteins, XoxG (a c-type cytochrome) and XoxJ (a periplasmic binding protein of unknown function), about which little is known. Here, we biochemically and structurally characterize these proteins from the methyltroph, Methylobacterium extorquens AM1. Read More

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https://onlinelibrary.wiley.com/doi/abs/10.1002/cbic.2019001
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http://dx.doi.org/10.1002/cbic.201900184DOI Listing
April 2019
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Mitochondria Targeting Fluorescent Probes Based on Through Bond Energy Transfer for Mutually Imaging Signaling Molecules H2S and H2O2.

Chemistry 2019 Apr 24. Epub 2019 Apr 24.

Nanjing University, Department of Polymer Science & Engineering, School of Chemistry & Chemical Engineering, No. 163 Xianlin Avenue, Qixia District, 210046, Nanjing, CHINA.

Reactive signaling molecules participate in varieties of biochemical reactions, and methods to detect their mutual existence and crosstalk are in urgent demand. We first designed a benzothiadiazole-based handle that fluorescently responds to the co-existence of H2S and H2O2 under pseudo-physiological conditions, and demonstrated a thiyl radical-mediated mechanism that accounts for the rapid and efficient domino-like reaction processes. Then we mounted the handle motif to a rhodamine moiety via an ethynylene linkage, and achieved a significant H2S-H2O2 mutual response in the mitochondria of living cells. Read More

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http://dx.doi.org/10.1002/chem.201900959DOI Listing

Pulsed EPR Dipolar Spectroscopy under the Breakdown of the High-Field Approximation: The High-Spin Iron(III) Case.

Chemistry 2019 Apr 24. Epub 2019 Apr 24.

University of Bonn, Institute of Physical and Theoretical Chemistry, Wegelerstr. 12, 53115, Bonn, GERMANY.

Pulsed EPR Dipolar Spectroscopy (PDS) offers several methods for measuring the dipolar coupling and thus the distance between electron-spin centers. Up to now, PDS measurements to metal centers were limited to ions that adhere to the high-field approximation. Here, the PDS methodology is extended to cases where the high-field approximation breaks down on the example of the high-spin Fe3+/nitroxide spin-pair. Read More

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http://dx.doi.org/10.1002/chem.201900977DOI Listing

Catalytic chemosensing assay for selective detection of methyl parathion organophosphate pesticide.

Chemistry 2019 Apr 24. Epub 2019 Apr 24.

The Education University of Hong Kong, Department of Science and Environmental Studies, 10 Lo Ping Road, Tai Po, New Territories, N.A., Hong Kong, HONG KONG.

Herein, a catalytic chemosensing assay (CCA), based on a bimetallic complex, [RuII(bpy)2(CN)2]2-(CuII)2 (bpy = 2,2'-bipyridine), has been described. This complex integrates a task-specific catalyst (CuI-catalyst) and a signaling unit ([RuII(bpy)2(CN)2]) to specifically hydrolyze methyl parathion, a highly toxic organophosphate pesticide (OP). The bimetallic complex catalyzed the hydrolysis of the phosphate ester to generate o,o-dimethyl thiophosphate (DTP) anion and 4-nitrophenolate. Read More

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http://dx.doi.org/10.1002/chem.201901656DOI Listing

Ditocopheryl sulfides and disulfides: Synthesis and antioxidant profile.

Chemistry 2019 Apr 24. Epub 2019 Apr 24.

ITALY.

Symmetrical ditocopheryl disulfides (Toc)2S2 and symmetrical and unsymmetrical ditocopheryl sulfides (Toc)2S were simply prepared under remarkably mild conditions with complete control of the regiochemistry using delta-, gamma-, and beta-tocopheryl-N-thiophthalimides (Toc-NSPht) as common starting materials. The role of the sulfur atom(s), H-bond and aryl ring substitution pattern on the antioxidant profile of these new compounds, assembled linking together two tocopheryl units, are also discussed. Read More

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http://dx.doi.org/10.1002/chem.201901537DOI Listing

Crystalline Divinyldiarsenes and Cleavage of the As=As Bond.

Chemistry 2019 Apr 24. Epub 2019 Apr 24.

GERMANY.

The first divinyldiarsenes [{(NHC)C(Ph)}As]2 (NHC = IPr 3a, SIPr 3b; IPr = C{(NAr)CH}2; SIPr = C{(NAr)CH2}2; Ar = 2,6-iPr2C6H3) are reported. 3a and 3b were prepared by the reduction of corresponding chlorides {(NHC)C(Ph)}AsCl2 (NHC = IPr 2a, SIPr 2b) with Mg. Calculations revealed a small HOMO-LUMO energy gap of 3. Read More

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http://dx.doi.org/10.1002/chem.201901857DOI Listing

Chemo- and Regioselective Catalyst-Controlled Carbocyclization of Alkynyl Ketones: Rapid Synthesis of 1-Indanones and 1-Naphthols.

Chemistry 2019 Apr 24. Epub 2019 Apr 24.

3001, Leuven, BELGIUM.

A catalyst-controlled intramolecular carbocyclization of 2-alkynylarylketones is developed. Under rhodium(III) catalysis, 1-indanones are formed through 5-exo-dig carbocyclization in exclusive chemo-, regio- and stereoselectivity. When catalyzed by copper(I), 1-naphthols are delivered via 6-endo-dig carbocyclization in exclusive chemo- and regioselectivty. Read More

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http://dx.doi.org/10.1002/chem.201901860DOI Listing
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