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Chemical dependency

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https://www.readbyqxmd.com/read/28641388/recognition-of-the-component-odors-in-mixtures
#1
Marion E Frank, Dane B Fletcher, Thomas P Hettinger
Natural olfactory stimuli are volatile-chemical mixtures in which relative perceptual saliencies determine which odor-components are identified. Odor identification also depends on rapid selective adaptation, as shown for 4 odor stimuli in an earlier experimental simulation of natural conditions. Adapt-test pairs of mixtures of water-soluble, distinct odor stimuli with chemical features in common were studied. Identification decreased for adapted components but increased for unadapted mixture-suppressed components, showing compound identities were retained, not degraded to individual molecular features...
June 21, 2017: Chemical Senses
https://www.readbyqxmd.com/read/28641237/tunable-excited-state-intramolecular-proton-transfer-reactions-with-nh-or-oh-as-a-proton-donor-a-theoretical-investigation
#2
Yuanyuan Li, Keke Wen, Songyan Feng, Huijuan Yuan, Beibei An, Qiuling Zhu, Xugeng Guo, Jinglai Zhang
Excited-state intramolecular proton transfer (ESIPT) reactions occurring in the S1 state for five molecules, which possess five/six-membered ring intramolecular NH···N or OH···N hydrogen bonds bearing quinoline or 2-phenylpyridine moiety, have been described in detail by the time-dependent density functional theory (TD-DFT) approach using the B3LYP hybrid functional. For the five molecules, the constrained potential energy profiles along the ESIPT reactions show that proton transfer is barrierless in molecules possessing six-membered ring intramolecular H-bonds, which is smoother than that with certain barriers in five-membered ring H-bonding systems...
June 15, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/28641225/investigation-of-dissociation-constants-for-individual-and-total-naphthenic-acids-species-using-ultra-performance-liquid-chromatography-ion-mobility-time-of-flight-mass-spectrometry-analysis
#3
Rongfu Huang, Pamela Chelme-Ayala, Yanyan Zhang, Mohamed Changalov, Mohamed Gamal El-Din
Ultra-performance liquid chromatography ion mobility time-of-flight mass spectrometry (UPLC-IM-TOFMS) was utilized for the analysis of naphthenic acids (NAs) in fractions of pH-dependent sequential liquid-liquid extractions from oil sands process-affected water. Ion-mobility separation technique allowed the differentiation of OyS-NAs (2 ≤ y ≤ 4) from Ox-NAs (2 ≤ x ≤ 5) via drift time versus retention time separations. The results indicated that the addition of S atom to the O2-NA molecule led to a lower increase in the dissociation constant (pKa) compared to that caused by the addition of O atom...
June 18, 2017: Chemosphere
https://www.readbyqxmd.com/read/28641195/biotransformation-in-the-zebrafish-embryo-temporal-gene-transcription-changes-of-cytochrome-p450-enzymes-and-internal-exposure-dynamics-of-the-ahr-binding-xenobiotic-benz-a-anthracene
#4
Agnes Kühnert, Carolina Vogs, Bettina Seiwert, Silke Aulhorn, Rolf Altenburger, Henner Hollert, Eberhard Küster, Wibke Busch
Not much is known about the biotransformation capability of zebrafish (Danio rerio) embryos. For understanding possible toxicity differences to adult fish, it might be crucial to understand the biotransformation of chemicals in zebrafish embryos i.e. as part of toxicokinetics. The biotransformation capabilities were analysed for two different stages of zebrafish embryos in conjunction with the internal concentrations of a xenobiotic. Zebrafish embryos of the late cleavage/early blastula period (2-26 hpf) and the early pharyngula period (26-50 hpf) were exposed for 24 h to the AhR binding compound benz[a]anthracene (BaA)...
June 19, 2017: Environmental Pollution
https://www.readbyqxmd.com/read/28641164/protective-effects-of-flavonoids-against-alzheimer-s-disease-related-neural-dysfunctions
#5
REVIEW
Mahsa Bakhtiari, Yunes Panahi, Javad Ameli, Behrad Darvishi
Senile ages of human life is mostly associated with developmental of several neurological complicated conditions including decreased cognition and reasoning, increased memory loss and impaired language performance. Alzheimer's disease (AD) is the most prevalent neural disorder associated with dementia, consisting of about 70% of dementia reported cases. Failure of currently approved chemical anti-AD therapeutic agents has once again brought up the idea of administering naturally occurring compounds as effective alternative and/or complementary regimens in AD treatment...
June 19, 2017: Biomedicine & Pharmacotherapy, Biomédecine & Pharmacothérapie
https://www.readbyqxmd.com/read/28640886/epigenomic-diversification-within-the-genus-lupinus
#6
Karolina Susek, Agnieszka Braszewska-Zalewska, Adam J Bewick, Robert Hasterok, Robert J Schmitz, Barbara Naganowska
Deciphering the various chemical modifications of both DNA and the histone compound of chromatin not only leads to a better understanding of the genome-wide organisation of epigenetic landmarks and their impact on gene expression but may also provide some insights into the evolutionary processes. Although both histone modifications and DNA methylation have been widely investigated in various plant genomes, here we present the first study for the genus Lupinus. Lupins, which are members of grain legumes (pulses), are beneficial for food security, nutrition, health and the environment...
2017: PloS One
https://www.readbyqxmd.com/read/28637166/comparison-of-the-anaerobic-digestion-at-the-mesophilic-and-thermophilic-temperature-regime-of-organic-wastes-from-the-agribusiness
#7
Daniela Almeida Streitwieser
An overall kinetic power law model has been successfully applied to study the anaerobic digestion of agricultural wastes. In this comparative kinetic study feed composition, organic load rate, residence time and process temperature have been systematically varied in an automated semi-continuous fermentation system to obtain the dependency of the rate of degradation as biogas production on the organic load rate and temperature. The results show that the overall reaction order depend only on the Chemical Oxygen Demand (COD) at values between 3...
June 17, 2017: Bioresource Technology
https://www.readbyqxmd.com/read/28637004/autophagy-is-required-for-crizotinib-induced-apoptosis-in-met-amplified-gastric-cancer-cells
#8
Rebecca D Schroeder, Woonyoung Choi, David S Hong, David J McConkey
MET amplification has been clinically credentialed as a therapeutic target in gastric cancer, but the molecular mechanisms underlying sensitivity and resistance to MET inhibitors are still not well understood. Using whole-genome mRNA expression profiling, we identified autophagy as a top molecular pathway that was activated by the MET inhibitor crizotinib in drug-sensitive human gastric cancer cells, and functional studies confirmed that crizotinib increased autophagy levels in the drug-sensitive cells in a concentration-dependent manner...
June 7, 2017: Oncotarget
https://www.readbyqxmd.com/read/28636625/comparison-study-of-exhaust-plume-impingement-effects-of-small-mono-and-bipropellant-thrusters-using-parallelized-dsmc-method
#9
Kyun Ho Lee
A space propulsion system is important for the normal mission operations of a spacecraft by adjusting its attitude and maneuver. Generally, a mono- and a bipropellant thruster have been mainly used for low thrust liquid rocket engines. But as the plume gas expelled from these small thrusters diffuses freely in a vacuum space along all directions, unwanted effects due to the plume collision onto the spacecraft surfaces can dramatically cause a deterioration of the function and performance of a spacecraft. Thus, aim of the present study is to investigate and compare the major differences of the plume gas impingement effects quantitatively between the small mono- and bipropellant thrusters using the computational fluid dynamics (CFD)...
2017: PloS One
https://www.readbyqxmd.com/read/28636622/inhibition-of-hepatitis-b-viral-entry-by-nucleic-acid-polymers-in-heparg-cells-and-primary-human-hepatocytes
#10
Clément Guillot, Nora Martel, Françoise Berby, Isabelle Bordes, Olivier Hantz, Matthieu Blanchet, Camille Sureau, Andrew Vaillant, Isabelle Chemin
Hepatitis B virus (HBV) infection remains a major public health concern worldwide with 240 million individuals chronically infected and at risk of developing cirrhosis and hepatocellular carcinoma. Current treatments rarely cure chronic hepatitis B infection, highlighting the need for new anti-HBV drugs. Nucleic acid polymers (NAPs) are phosphorothioated oligonucleotides that have demonstrated a great potential to inhibit infection with several viruses. In chronically infected human patients, NAPs administration lead to a decline of blood HBsAg and HBV DNA and to HBsAg seroconversion, the expected signs of functional cure...
2017: PloS One
https://www.readbyqxmd.com/read/28636342/charge-transfer-properties-of-triarylamine-integrated-dimolybdenum-dyads
#11
Lu Chen, Suman Mallick, Ying Ning Tan, Miao Meng, Chun Y Liu
Three quadruply bonded dimolybdenum complexes equipped with a triarylamine pendant, [(DAniF)3Mo2(μ-O2CC6H4N(C6H4CH3)2] (DAniF = N,N'-di(p-anisyl)formamidinate; [OO-ph-N]), [(DAniF)3Mo2(μ-OSCC6H4N(C6H4CH3)2] ([OS-ph-N]), and [(DAniF)3Mo2(μ-S2CC6H4N(C6H4CH3)2] ([SS-ph-N]), have been synthesized and characterized by single crystal X-ray diffraction. In electrochemical measurements, the redox couple for the organic amine group becomes irreversible, reflecting the substantially strong electronic interaction between the dimetal center and organic redox site...
June 21, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28636052/chemically-induced-degradation-of-cdk9-by-a-proteolysis-targeting-chimera-protac
#12
Caroline M Robb, Jacob I Contreras, Smit Kour, Margaret A Taylor, Mohammad Abid, Yogesh A Sonawane, Muhammad Zahid, Daryl J Murry, Amarnath Natarajan, Sandeep Rana
Cyclin-dependent kinase 9 (CDK9), a member of the cyclin-dependent protein kinase (CDK) family, is involved in transcriptional elongation of several target genes. CDK9 is ubiquitously expressed and has been shown to contribute to a variety of malignancies such as pancreatic, prostate and breast cancers. Here we report the development of a heterobifunctional small molecule proteolysis targeting chimera (PROTAC) capable of cereblon (CRBN) mediated proteasomal degradation of CDK9. In HCT116 cells, it selectively degrades CDK9 while sparing other CDK family members...
June 21, 2017: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/28636013/new-insights-into-the-solubility-of-graphene-oxide-in-water-and-alcohols
#13
Vadim V Neklyudov, Nail R Khafizov, Igor A Sedov, Ayrat M Dimiev
One of the main advantages of graphene oxide (GO) over its non-oxidized counterpart is its ability to form stable solutions in water and some organic solvents. At the same time, the nature of GO solutions is not completely understood; the existing data are scarce and controversial. Here, we demonstrate that the solubility of GO, and the stability of the as-formed solutions depend not just on the solute and solvent cohesion parameters, as commonly believed, but mostly on the chemical interactions at the GO/solvent interface...
June 21, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28635651/effects-of-tetrodotoxin-in-mouse-models-of-visceral-pain
#14
Rafael González-Cano, Miguel Ángel Tejada, Antonia Artacho-Cordón, Francisco Rafael Nieto, José Manuel Entrena, John N Wood, Cruz Miguel Cendán
Visceral pain is very common and represents a major unmet clinical need for which current pharmacological treatments are often insufficient. Tetrodotoxin (TTX) is a potent neurotoxin that exerts analgesic actions in both humans and rodents under different somatic pain conditions, but its effect has been unexplored in visceral pain. Therefore, we tested the effects of systemic TTX in viscero-specific mouse models of chemical stimulation of the colon (intracolonic instillation of capsaicin and mustard oil) and intraperitoneal cyclophosphamide-induced cystitis...
June 21, 2017: Marine Drugs
https://www.readbyqxmd.com/read/28635550/peptide-grafted-and-self-assembled-poly-%C3%AE-glutamic-acid-phenylalanine-nanoparticles-targeting-camptothecin-to-glioma
#15
Hitesh Kulhari, Srinivasa R Telukutla, Deep Pooja, Ravi Shukla, Ramakrishna Sistla, Vipul Bansal, David J Adams
AIM: To synthesize cRGDfK peptide conjugated poly(γ-glutamic acid)-phenylalanine nanoparticles to improve the therapeutic efficacy of camptothecin (CPT) against glioblastoma multiforme. METHODS: Peptide-conjugated, drug-loaded nanoparticles (cRGDfK-conjugated camptothecin-loaded PGA-PA nanoparticles [RCPN]) were prepared and physico-chemically characterized using different techniques. Nanoparticles were evaluated for in vitro anticancer activity, cellular uptake, induction of apoptosis and wound healing cell migration against U87MG human glioblastoma cells...
June 21, 2017: Nanomedicine
https://www.readbyqxmd.com/read/28635268/isotope-controlled-selectivity-by-quantum-tunneling-hydrogen-migration-versus-ring-expansion-in-cyclopropylmethylcarbenes
#16
Ashim Nandi, Dennis Gerbig, Peter R Schreiner, Weston Thatcher Borden, Sebastian Kozuch
Using the tunneling-controlled reactivity of cyclopropylmethylcar-bene, we demonstrate the viability of isotope-controlled selectivity (ICS), a novel non-classical control element of chemical reactivity where a molecular system with two conceivable products of tunneling exclusively produces one or the other, depending only on isotopic composition. Our multidimensional small-curvature tunneling (SCT) computations indicate that under cryogenic conditions, 1-methoxycyclopropylmethylcarbene shows rapid H-migration to 1-methoxy-1-vinylcyclopropane, whereas deuterium-substituted 1-methoxycyclopropyl-d3-methylcarbene undergoes ring expansion to 1-d3-methylcyclobutene...
June 21, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28633424/three-dimensional-3d-heparg-spheroid-model-with-physiologically-relevant-xenobiotic-metabolism-competence-and-hepatocyte-functionality-for-liver-toxicity-screening
#17
Sreenivasa C Ramaiahgari, Suramya Waidyanatha, Darlene Dixon, Michael J DeVito, Richard S Paules, Stephen S Ferguson
Effective prediction of human responses to chemical and drug exposure is of critical importance in environmental toxicology research and drug development. While significant progress has been made to address this challenge using in vitro liver models, these approaches often fail due to inadequate tissue model functionality. Herein, we describe the development, optimization, and characterization of a novel three-dimensional (3D) spheroid model using differentiated HepaRG cells that achieve and maintain physiologically-relevant levels of xenobiotic metabolism (CYP1A2, CYP2B6, and CYP3A4/5)...
June 15, 2017: Toxicological Sciences: An Official Journal of the Society of Toxicology
https://www.readbyqxmd.com/read/28632392/lewis-acid-promoted-hydrogenation-of-co2-and-hcoo-by-amine-boranes-mechanistic-insight-from-computational-approach
#18
Lisa Roy, Boyli Ghosh, Ankan Paul
We employ quantum chemical calculations to study the hydrogenation of carbon dioxide by amine-boranes, NMe3BH3 ((Me3)AB) and NH3BH3 (AB) weakly bonded to a bulkier Lewis acid, Al(C6F5)3 (LA). Additionally, computations has also been conducted to elucidate the mechanism of hydrogenation of carbon dioxide by (Me3)AB while captured between one Lewis Base (P(o-tol3), (LB)) and two Lewis acids, Al(C6F5)3. In agreement to the experiments, our computational study predicts that hydride transfer to conjugated HCO2(‒), generated in the reaction of (Me3)AB-LA with CO2, is not feasible...
June 20, 2017: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/28632382/manipulation-of-chain-conformation-for-optimum-charge-transport-pathway-in-conjugated-polymers
#19
Seolhee Jeon, Jung Hun Lee, Jai Il Park, Bonghyun Jo, Dong Ryeol Whang, Tae Kyu Ahn, Hui Joon Park, Sung Dong Kim, Wi Hyoung Lee, Bong-Gi Kim
Two different diketopyrrolopyrrole-based conjugated polymers (CPs) were designed and synthesized to investigate the effect of chain conformation on their molecular assembly. Conformation management was achieved by the incorporation of different linkers during polymerization. Using computational calculations and UV-vis absorption measurements, the resulting CPs were found to exhibit partly modulated chain geometry. Grazing incident X-ray diffraction experiment with a 2-dimensional detector revealed that PDPP-T having a planar chain conformation exhibited an edge-on type molecular arrangement, which evolved to a face-on type chain assembly when the planar geometry was altered to a slightly twisted one as in PDPP-BT...
June 20, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28631839/natural-variability-of-biochemical-biomarkers-in-the-macro-zoobenthos-dependence-on-life-stage-and-environmental-factors
#20
Lucia Scarduelli, Roberto Giacchini, Paolo Parenti, Sonia Migliorati, Agnese Maria Di Brisco, Marco Vighi
Biomarkers are widely used in ecotoxicology as indicators of exposure to toxicants. However, their ability to provide ecologically relevant information remains controversial. One of the major problems is understanding if the measured responses are determined by stress factors or lie within the natural variability range. In a previous work, the natural variability of enzymatic levels in invertebrates sampled in pristine rivers was proved to be relevant across both space and time. In this work, the experimental design was improved by considering different life stages of the selected taxa and by measuring more environmental parameters...
June 20, 2017: Environmental Toxicology and Chemistry
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