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https://www.readbyqxmd.com/read/28231608/quantitative-analysis-of-malondialdehyde-guanine-adducts-in-genomic-dna-samples-by-liquid-chromatography-tandem-mass-spectrometry
#1
S A Yates, N M Dempster, M F Murphy, S A Moore
RATIONALE: The lipid peroxidation product malondialdehyde forms M1 dG adducts with guanine bases in genomic DNA. The analysis of these adducts is important as a biomarker of lipid peroxidation, oxidative stress and inflammation which may be linked to disease risk or exposure to a range of chemicals. METHODS: Genomic DNA samples were subjected to acid hydrolysis to release the adducts in the base form (M1 G) alongside the other purines. A liquid chromatography-mass spectrometry method was optimised for the quantitation of the M1 G adducts in genomic DNA samples using product ion and multiple reaction mode scans...
February 23, 2017: Rapid Communications in Mass Spectrometry: RCM
https://www.readbyqxmd.com/read/28231012/quantum-percolation-and-magnetic-nano-droplet-states-in-electronically-phase-separated-manganite-nanowires
#2
Kaixuan Zhang, Lin Li, Hui Li, Qiyuan Feng, Nan Zhang, Long Cheng, Xiaodong Fan, Yubin Hou, Qingyou Lu, Zhenyu Zhang, Changgan Zeng
One-dimensional (1D) confinement has been revealed to effectively tune the properties of materials in homogeneous states. The 1D physics can be further enriched by electronic inhomogeneity, which unfortunately remains largely unknown. Here we demonstrate the ultra-high sensitivity to magnetic fluctuations and the tunability of phase stability in the electronic transport properties of self-assembled electronically phase-separated manganite nanowires with extreme aspect ratio. The onset of magnetic nano-droplet state, a precursor to the ferromagnetic metallic state, is unambiguously revealed, which is attributed to the small lateral size of the nanowires that is comparable to the droplet size...
February 23, 2017: Nano Letters
https://www.readbyqxmd.com/read/28230996/a-facile-n-mercaptoethoxyglycinamide-mega-linker-ap-proach-to-peptide-thioesterification-and-cyclization
#3
Patrick M M Shelton, Caroline E Weller, Champak Chatterjee
The C-terminal selective electrophilic activation of polypeptides is essential for site-specific peptide mod-ification and conjugation techniques such as Native Chemi-cal Ligation (NCL). Peptide C-terminal α-thioesters are par-ticularly valuable precursors for NCL, due to their hydrolytic stability in aqueous buffers and reactivity toward thiol nucle-ophiles. The synthesis of peptide α-thioesters, however, re-quires harsh acidic conditions or complex chemical manipu-lations, which ultimately limits their functional group com-patibility and broad utility...
February 23, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28230972/paclitaxel-biosynthesis-adenylation-and-thiolation-domains-of-an-nrps-tyca-pheat-module-produce-various-arylisoserine-coa-thioesters
#4
Ruth Muchiri, Kevin D Walker
Structure-activity relationship studies show that the phenylisoserinyl moiety of paclitaxel is largely necessary for the effective anticancer activity. Several paclitaxel analogs with a variant isoserinyl sides chain have improved pharmaceutical properties over the parent drug. To produce the isoserinyl CoAs as intermediates needed for enzyme catalysis on a semibiosynthetic pathway to paclitaxel analogs, we repurposed the adenylation and thiolation domains of a non-ribosomal peptide synthetase (Phe-AT) to function as a CoA ligase...
February 23, 2017: Biochemistry
https://www.readbyqxmd.com/read/28230971/multifaceted-gold-palladium-bimetallic-nanorods-and-their-geometric-compositional-and-catalytic-tunabilities
#5
Lichao Sun, Qingfeng Zhang, Guangfang Grace Li, Esteban Villarreal, Xiaoqi Fu, Hui Wang
Kinetically controlled, seed-mediated coreduction provides a robust and versatile synthetic approach to multimetallic nanoparticles with precisely controlled geometries and compositions. Here we demonstrate that single-crystalline cylindrical Au nanorods selectively transform into a series of structurally distinct Au@Au-Pd alloy core-shell bimetallic nanorods with exotic multifaceted geometries enclosed by specific types of facets upon seed-mediated Au-Pd coreduction under diffusion controlled conditions. By adjusting several key synthetic parameters, such as the Pd/Au precursor ratio, the reducing agent concentration, the capping surfactant concentration, and foreign metal ion additives, we have been able to simultaneously fine-tailor the atomic-level surface structures and fine-tune the compositional stoichiometries of the multifaceted Au-Pd bimetallic nanorods...
February 23, 2017: ACS Nano
https://www.readbyqxmd.com/read/28230966/increasing-peak-capacity-in-non-targeted-omics-applications-by-combining-full-scan-field-asymmetric-waveform-ion-mobility-spectrometry-with-liquid-chromatography-mass-spectrometry
#6
Kayleigh L Arthur, Matthew A Turner, James C Reynolds, Colin S Creaser
Full scan field asymmetric waveform ion mobility spectrometry (FAIMS) combined with liquid chromatography and mass spectrometry (LC-FAIMS-MS) is shown to enhance peak capacity for omics applications. A miniaturized FAIMS device capable of rapid compensation field scanning has been incorporated into an ultra-high performance liquid chromatography (UHPLC) and time-of-flight (TOF) mass spectrometry analysis, allowing the acquisition of full scan FAIMS and MS nested data sets within the timescale of a UHPLC peak...
February 23, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28230880/atomic-layer-deposited-ultrafine-mos2-nanocrystals-on-cobalt-foam-for-efficient-and-stable-electrochemical-oxygen-evolution
#7
Dehua Xiong, Qingqing Zhang, Wei Li, Junjie Li, Xiuli Fu, M F Cerqueira, Pedro Alpuim, Lifeng Liu
Ultrafine molybdenum sulfide (MoS2) nanocrystals are grown on a porous cobalt (Co) foam current collector by atomic layer deposition (ALD) using molybdenum hexacarbonyl and hydrogen sulfide as precursors. When used to catalyze the oxygen evolution reaction (OER), the optimal Co@MoS2 electrode, even with a MoS2 loading as small as 0.06 mg cm(-2), exhibits a large cathodic shift of ca. 200 mV in the onset potential (the potential at which the current density is 5 mA cm(-2)), a low overpotential of only 270 mV to attain an anodic current density of 10 mA cm(-2), much smaller charge transfer resistance and substantially improved long-term stability at both low and high current densities, with respect to the bare Co foam electrode, showing substantial promise for use as an efficient, low-cost and durable anode in water electrolyzers...
February 23, 2017: Nanoscale
https://www.readbyqxmd.com/read/28230754/green-hydroselenation-of-aryl-alkynes-divinyl-selenides-as-a-precursor-of-resveratrol
#8
Gelson Perin, Angelita M Barcellos, Eduardo Q Luz, Elton L Borges, Raquel G Jacob, Eder J Lenardão, Luca Sancineto, Claudio Santi
A simple and efficient protocol to prepare divinyl selenides has been developed by the regio- and stereoselective addition of sodium selenide species to aryl alkynes. The nucleophilic species was generates in situ, from the reaction of elemental selenium with NaBH₄, utilizing PEG-400 as the solvent. Several divinyl selenides were obtained in moderate to excellent yields with selectivity for the (Z,Z)-isomer by a one-step procedure that was carried out at 60 °C in short reaction times. The methodology was extended to tellurium, giving the desired divinyl tellurides in good yields...
February 20, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/28230375/three-component-coupling-of-triflyloxy-substituted-benzocyclobutenones-organolithium-reagents-and-arynophiles-promoted-by-generation-of-aryne-via-carbon-carbon-bond-cleavage
#9
Keisuke Uchida, Suguru Yoshida, Takamitsu Hosoya
Treatment of benzocyclobutenones bearing a triflyloxy group adjacent to the four-membered ring with organolithium reagents in the presence of arynophiles efficiently affords three-component coupled α-arylketones. Mechanistic studies indicate that the reaction is promoted by generation of the aryne via carbon-carbon bond cleavage of a benzocyclobutenoxide intermediate, which led us to find a fluoride-mediated aryne generation method from triflyloxy-substituted benzocyclobutenone silyl acetal precursors.
February 23, 2017: Organic Letters
https://www.readbyqxmd.com/read/28230317/p-cymene-as-a-solvent-for-olefin-metathesis-matching-efficiency-and-sustainability
#10
Eduardo N Dos Santos, Artur V Granato, Alexandra G Santos
The underexploited, biorenewable, p-cymene is employed as a solvent for the metathesis of various substrates. p-cymene is a nontoxic compound that can be obtained in large amounts from side product of cellulose and citrus industry. For the cross-metathesis of estragole with methyl acrylate, this solvent prevents the consecutive double-bond isomerization of the product and gives the best yield of all solvents tested. Undesired consecutive isomerization is a major problem for many substrates in olefin metathesis, including pharmaceutical precursors, and the use of p-cymene as solvent may be a way to prevent it...
February 23, 2017: ChemSusChem
https://www.readbyqxmd.com/read/28230278/deletion-of-psychiatric-risk-gene-cacna1c-impairs-hippocampal-neurogenesis-in-cell-autonomous-fashion
#11
Bianca Völkening, Kai Schönig, Golo Kronenberg, Dusan Bartsch, Tillmann Weber
Ca(2+) is a universal signal transducer which fulfills essential functions in cell development and differentiation. CACNA1C, the gene encoding the alpha-1C subunit (i.e., Cav 1.2) of the voltage-dependent l-type calcium channel (LTCC), has been implicated as a risk gene in a variety of neuropsychiatric disorders. To parse the role of Cav 1.2 channels located on astrocyte-like stem cells and their descendants in the development of new granule neurons, we created Tg(GLAST-CreERT2) /Cacna1c(fl/fl) /RCE:loxP mice, a transgenic tool that allows cell-type-specific inducible deletion of Cacna1c...
February 23, 2017: Glia
https://www.readbyqxmd.com/read/28230272/sizing-up-a-superstorm-exploring-the-role-of-recalled-experience-and-attribution-of-responsibility-in-judgments-of-future-hurricane-risk
#12
Laura N Rickard, Z Janet Yang, Jonathon P Schuldt, Gina M Eosco, Clifford W Scherer, Ricardo A Daziano
Research suggests that hurricane-related risk perception is a critical predictor of behavioral response, such as evacuation. Less is known, however, about the precursors of these subjective risk judgments, especially when time has elapsed from a focal event. Drawing broadly from the risk communication, social psychology, and natural hazards literature, and specifically from concepts adapted from the risk information seeking and processing model and the protective action decision model, we examine how individuals' distant recollections, including attribution of responsibility for the effects of a storm, attitude toward relevant information, and past hurricane experience, relate to risk judgment for a future, similar event...
February 23, 2017: Risk Analysis: An Official Publication of the Society for Risk Analysis
https://www.readbyqxmd.com/read/28230087/nardilysin-regulates-inflammation-metaplasia-and-tumors-in-murine-stomach
#13
Yuto Kimura, Kozo Ikuta, Takeshi Kimura, Tsutomu Chiba, Hiroko Oshima, Masanobu Oshima, Eiichiro Nishi, Hiroshi Seno
Chronic inflammation contributes to a wide variety of human disorders. In the stomach, longstanding gastritis often results in structural alterations in the gastric mucosa, including metaplastic changes and gastric cancers. Therefore, it is important to elucidate factors that are involved in gastric inflammation. Nardilysin (N-arginine dibasic convertase; Nrdc) is a metalloendopeptidase of the M16 family that promotes ectodomain shedding of the precursor forms of various growth factors and cytokines by enhancing the protease activities of a disintegrin and metalloproteinase (ADAM) proteins...
February 23, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28230075/oxygen-impairs-oligodendroglial-development-via-oxidative-stress-and-reduced-expression-of-hif-1%C3%AE
#14
Christina Brill, Till Scheuer, Christoph Bührer, Stefanie Endesfelder, Thomas Schmitz
The premature increase of oxygen tension may contribute to oligodendroglial precursor cell (OPC) damage in preterm infants. Fetal OPCs are exposed to low oxygen tissue tensions not matched when cells are cultured in room air. Maturation (A2B5, O4, O1, MBP, CNP, arborization), oxidative stress (nitrotyrosine Western blot, NRF2 and SOD2 expression), apoptosis (TUNEL), proliferation (Ki67), and expression of transcription factors regulated by Hypoxia-Inducible-Factor-1-alpha (Hif-1α) expressed in OPCs (Olig1, Olig2, Sox9, Sox10) were assessed in rat OPCs and OLN93 cells cultured at 5% O2 and 21% O2...
February 23, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28229612/preliminary-results-of-a-screening-program-for-anal-cancer-and-its-precursors-for-hiv-infected-men-who-have-sex-with-men-in-vigo-spain
#15
Mauricio Iribarren Díaz, Antonio Ocampo Hermida, Joaquín González-Carreró Fojón, Rebeca Longueira Suárez, Alberto Rivera Gallego, Enrique Casal Núñez, Antón Ocampo Álvarez, Edward Cachay
BACKGROUND: Men who have sex with men (MSM) infected with human immunodeficiency virus (HIV) have the highest risk of developing anal cancer (AC). The objective of this study was to describe our screening implementation program in this population, and report the prevalence of human papillomavirus (HPV) anal infection, and cytological and histological findings in a Spanish medium-size community (Vigo, Spain). METHOD: Prospective cohort analysis of 240 HIV-infected MSM...
February 23, 2017: Revista Española de Enfermedades Digestivas
https://www.readbyqxmd.com/read/28229414/isolation-and-culture-of-satellite-cells-from-mouse-skeletal-muscle
#16
Antonio Musarò, Silvia Carosio
Skeletal muscle tissue is characterized by a population of quiescent mononucleated myoblasts, localized between the basal lamina and sarcolemma of myofibers, known as satellite cells. Satellite cells play a pivotal role in muscle homeostasis and are the major source of myogenic precursors in mammalian muscle regeneration.This chapter describes protocols for isolation and culturing satellite cells isolated from mouse skeletal muscles. The classical procedure, which will be discussed extensively in this chapter, involves the enzymatic dissociation of skeletal muscles, while the alternative method involves isolation of satellite cells from isolated myofibers in which the satellite cells remain in their in situ position underneath the myofiber basal lamina...
2017: Methods in Molecular Biology
https://www.readbyqxmd.com/read/28229413/cardiac-progenitor-cell-extraction-from-human-auricles
#17
Paolo Di Nardo, Francesca Pagliari
For many years, myocardial tissue has been considered terminally differentiated and, thus, incapable of regenerating. Recent studies have shown, instead, that cardiomyocytes, at least in part, are slowly substituted by new cells originating by precursor cells mostly embedded into the heart apex and in the atria. We have shown that an elective region of progenitor cell embedding is represented by the auricles, non-contractile atria appendages that can be easily sampled without harming the patient. The protocol here reported describes how from auricles a population of multipotent, cardiogenic cells can be isolated, cultured, and differentiated...
2017: Methods in Molecular Biology
https://www.readbyqxmd.com/read/28229187/-precursors-of-gastric-cancer-dysplasia-and-adenoma
#18
C Langner
Gastric cancer develops from preneoplastic and early neoplastic precursor lesions. In particular, the intestinal type according to the Lauren classification is driven by chronic inflammation and progresses via a chronic gastritis - atrophy/metaplasia - dysplasia - carcinoma sequence. Staging of the extent of atrophy (OLGA) or intestinal metaplasia (OLGIM) enables risk stratification and determines follow-up investigations according to the management of precancerous conditions and lesions in the stomach (MAPS) international guidelines...
February 22, 2017: Der Pathologe
https://www.readbyqxmd.com/read/28229143/metal-free-nitroxyl-radical-mediated-%C3%AE-c-sp-3-h-amination-of-saturated-ketones-with-heteroaryl-halides-multiple-roles-of-tempo
#19
Ping Qian, Yu Deng, Haibo Mei, Jianlin Han, Yi Pan
The first metal-free nitroxyl-radical-mediated β-amination of saturated ketones by using heteroaryl halides as amide precursors has been developed. This reaction proceeds through a cascade α-aminoxylation/Cope-like elimination/aza-Michael addition sequence to afford β-amino ketone derivatives with excellent yields. TEMPO plays multiple roles in the current β-amination process, including those of an oxidant, an α-aminoxylation reagent, a β-hydrogen acceptor, an in situ base, and an oxygen source.
February 23, 2017: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/28229135/the-colonic-metabolites-dihydrocaffeic-acid-and-dihydroferulic-acid-are-more-effective-inhibitors-of-in-vitro-platelet-activation-than-their-phenolic-precursors
#20
Gema Baeza, Eva-Maria Bachmair, Sharon Wood, Raquel Mateos, Laura Bravo, Baukje de Roos
Cardiovascular disease (CVD) is the major cause of morbidity and mortality worldwide. The consumption of a healthy diet rich in polyphenols has been inversely associated with the development of CVD. This study evaluated the effects of green coffee bean extract (GCBE) and yerba mate phenolic extract (YMPE), the main phenolic and methylxanthine constituents (5-caffeoylquinic acid, 3,5-dicaffeoylquinic acid, caffeine, and theobromine), and their main metabolites (caffeic acid, ferulic acid, dihydrocaffeic acid (DHCA) and dihydroferulic acid (DHFA)) on platelet activation in vitro...
February 23, 2017: Food & Function
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