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Timothy J Ritchie, Simon J F Macdonald
The impact of replacing a mono-substituted benzene (phenyl) ring with thirty three aromatic and nine aliphatic heterocycles on nine ADME-related screens (solubility, lipophilicity, permeability, protein binding CYP450 inhibition and metabolic clearance) was assessed using matched molecular pair analysis. The results indicate that the influence on the ADME profile can differ significantly depending on the ring identity and importantly on the individual regioisomers that are possible for some rings. This information enables the medicinal chemist to make an informed choice about which rings and regioisomers to employ as mono-substituted benzene replacements, based upon the knowledge of how such replacements are likely to influence ADME-related parameters, for example to target higher solubility whilst avoiding CYP450 liabilities...
October 15, 2016: European Journal of Medicinal Chemistry
Vanessa I S Mendes, Geoffrey A Bartholomeusz, Mary Ayres, Varsha Gandhi, Jorge A R Salvador
No abstract text is available yet for this article.
October 23, 2016: European Journal of Medicinal Chemistry
Ming Wang, Qiaoling Fan, Xuefeng Jiang
A facile, straightforward protocol was established for diarylannulated sulfide and selenide construction through S-I and Se-I exchange without transition metal assistance. Elemental sulfur and selenium served as the chalcogen source. Diarylannulated sulfides were systematically achieved from a five- to eight-membered ring. A trisulfur radical anion was demonstrated as the initiator for this radical process via electron paramagnetic resonance (EPR) study. OFET molecules [1]benzothieno[3,2-b][1]benzothiophene (BTBT) and [1]benzothieno[3,2-b][1]benzoselenophene (BTBS) were efficiently established...
October 26, 2016: Organic Letters
Katharina Witte, Cornelia Streeck, Ioanna Mantouvalou, Svetlana A Suchkova, Heiko Lokstein, Daniel Groetzsch, Wjatscheslav Martyanov, Jan Weser, Birgit Kanngiesser, Burkhard Beckhoff, Holger Stiel
The interaction of the central magnesium atom of chlorophyll a (Chl a) with its carbon and nitrogen backbone was investigated by magnesium (Mg) K near edge X-ray absorption fine structure (NEXAFS) spectroscopy in fluorescence detection mode. Chl a was measured as 1*10(-2) mol/l ethanol solution, which represents an upper limit of concentration without aggregation and as dried droplets. For the first time, the investigation of the structure of Chl a in a liquid environment by means of X-ray absorption spectroscopy is demonstrated...
October 26, 2016: Journal of Physical Chemistry. B
Peter Olsén, Jenny Undin, Karin Odelius, Helmut Keul, Ann-Christine Albertsson
Full control over the ceiling temperature (Tc) enables a selective transition between the monomeric and polymeric state. This is exemplified by the conversion of the monomer 2-allyloxymethyl-2-ethyl-trimethylene carbonate (AOMEC) to poly(AOMEC) and back to AOMEC within 10 h by controlling the reaction from conditions that favor ring-opening polymerization (Tc > T0) (where T0 is the reaction temperature) to conditions that favor ring-closing depolymerization (Tc < T0). The ring-closing depolymerization (RCDP) mirrors the polymerization behavior, with a clear relation between the monomer concentration and the molecular weight of the polymer, indicating that RCDP occurs at the chain end...
October 26, 2016: Biomacromolecules
Kit Man Wong, Lindsey N Micel, Heather M Selby, Aik Choon Tan, Todd M Pitts, Stacey M Bagby, Anna Spreafico, Peter J Klauck, Stephen J Blakemore, Peter F Smith, Alice McDonald, Allison Berger, John J Tentler, S Gail Eckhardt
Background The neddylation pathway conjugates NEDD8 to cullin-RING ligases and controls the proteasomal degradation of specific proteins involved in essential cell processes. Pevonedistat (MLN4924) is a selective small molecule targeting the NEDD8-activating enzyme (NAE) and inhibits an early step in neddylation, resulting in DNA re-replication, cell cycle arrest and death. We investigated the anti-tumor potential of pevonedistat in preclinical models of melanoma. Methods Melanoma cell lines and patient-derived tumor xenografts (PDTX) treated with pevonedistat were assessed for viability/apoptosis and tumor growth, respectively, to identify sensitive/resistant models...
October 25, 2016: Investigational New Drugs
Akihiro Okano, Shigeru Kato, Masaya Ohana
The incidence of Helicobacter pylori-negative gastric cancer (HpNGC) is extremely low. A 78-year old female without H. pylori infection was diagnosed with type 4 advanced-stage gastric prepylorus cancer. Distal gastrectomy was performed as for HpNGC (cT3N0M0). Histological findings of the resected specimen showed poorly differentiated adenocarcinoma and signet ring cell carcinoma, which were located in the pyloric gland area, diffusely invaded beyond the serosa without lymph node metastasis (pT4aN0M0). Most cases of undifferentiated-type HpNGC are diagnosed in the early stage and are located in the fundic gland area...
October 25, 2016: Clinical Journal of Gastroenterology
Seiichi Yamamoto, Tadashi Watabe, Hayato Ikeda, Yasukazu Kanai, Kazuhiro Ichikawa, Motonao Nakao, Katsuhiko Kato, Jun Hatazawa
PURPOSE: Positron emission tomography (PET) has high sensitivity for imaging radioactive tracer distributions in subjects. However, it is not possible to image free radical distribution in a subject by PET. Since free radicals are quite reactive, they are related to many diseases, including but not limited to cancer, inflammation, strokes, and heart disease. The Overhauser enhanced magnetic resonance imaging (OMRI) is so far the only method that images free radical distribution in vivo...
October 2016: Medical Physics
D Möncke, E I Kamitsos, D Palles, R Limbach, A Winterstein-Beckmann, T Honma, Z Yao, T Rouxel, L Wondraczek
A series of transition and post-transition metal ion (Mn, Cu, Zn, Pb, Bi) binary borate glasses was studied with special consideration of the cations impact on the borate structure, the cations cross-linking capacity, and more generally, structure-property correlations. Infrared (IR) and Raman spectroscopies were used for the structural characterization. These complementary techniques are sensitive to the short-range order as in the differentiation of tetrahedral and trigonal borate units or regarding the number of non-bridging oxygen ions per unit...
September 28, 2016: Journal of Chemical Physics
Lijun Yang, Honglei Yang, Hongyuan Zhang, Haoyun Wei, Yan Li
We propose a stable method for repetition rate multiplication of a 250-MHz Er-fiber frequency comb by a phase-locked all-pass fiber ring resonator, whose phase-locking configuration is simple. The optical path length of the fiber ring resonator is automatically controlled to be accurately an odd multiple of half of the original cavity length using an electronical phase-locking unit with an optical delay line. As for shorter cavity length of the comb, high-order odd multiple is preferable. Because the power loss depends only on the net-attenuation of the fiber ring resonator, the energetic efficiency of the proposed method is high...
September 2016: Review of Scientific Instruments
E Villa, J Cagigas, B Aja, L de la Fuente, E Artal
A 30% bandwidth phase shifter with four phase states is designed to be integrated in a radio astronomy receiver. The circuit has two 90° out-of-phase microwave phase-shifting branches which are combined by Wilkinson power dividers. Each branch is composed of a 180° phase shifter and a band-pass filter. The 180° phase shifter is made of cascaded hybrid rings with microwave PIN diodes as switching devices. The 90° phase shift is achieved with the two band-pass filters. Experimental characterization has shown significant results, with average phase shift values of -90...
September 2016: Review of Scientific Instruments
Lei Liu, Cui-E Hu, Mei Tang, Xiang-Rong Chen, Ling-Cang Cai
The low-lying isomers of cationic water cluster (H2O)6(+) have been globally explored by using particle swarm optimization algorithm in conjunction with quantum chemical calculations. Compared with previous results, our searching method covers a wide range of structural isomers of (H2O)6(+) and therefore turns out to be more effective. With these local minima, geometry optimization and vibrational analysis are performed for the most interesting clusters at second-order Møller-Plesset (MP2)/aug-cc-pVDZ level, and their energies are further refined at MP2/aug-cc-pVTZ and coupled-cluster theory with single, double, and perturbative triple excitations/aug-cc-pVDZ level...
October 21, 2016: Journal of Chemical Physics
Maria A Trachsel, Timo Wiedmer, Susan Blaser, Hans-Martin Frey, Quansong Li, Sergi Ruiz-Barragan, Lluís Blancafort, Samuel Leutwyler
We have investigated the S0 → S1 UV vibronic spectrum and time-resolved S1 state dynamics of jet-cooled amino-keto 1-methylcytosine (1MCyt) using two-color resonant two-photon ionization, UV/UV holeburning and depletion spectroscopies, as well as nanosecond and picosecond time-resolved pump/delayed ionization measurements. The experimental study is complemented with spin-component-scaled second-order coupled-cluster and multistate complete active space second order perturbation ab initio calculations. Above the weak electronic origin of 1MCyt at 31 852 cm(-1) about 20 intense vibronic bands are observed...
October 7, 2016: Journal of Chemical Physics
Yaacov Netanel Oded, Sergey Pogodin, Israel Agranat
Intramolecular Scholl reaction of 1-benzoylpyrene (1) gave 8H-dibenzo[def,qr]chrysen-8-one (2) and 11H-indeno[2,1-a]pyren-11-one (3) in a 1:2 ratio. The structures of 2 and 3 were determined, using (1)H NMR, (13)C NMR, and IR spectroscopies. A DFT B3LYP/6-311G(d,p) study of the reaction's arenium-cation mechanism of (E)-1 and (Z)-1 giving 2 and 3, respectively, indicated the reaction's regioselectivity and kinetic control. The analogous reaction of 1-(1'-naphthoyl)pyrene gave exclusively 13H-benz[4,5]indeno[2,1-a]pyren-13-one...
October 26, 2016: Journal of Organic Chemistry
Raúl Sánchez-Salguero, J Julio Camarero, Emilia Gutiérrez, Fidel González Rouco, Antonio Gazol, Gabriel Sangüesa-Barreda, Laia Andreu-Hayles, Juan Carlos Linares, Kristina Seftigen
Growth models can be used to assess forest vulnerability to climate warming. If global warming amplifies water deficit in drought-prone areas, tree populations located at the driest and southernmost distribution limits (rear-edges) should be particularly threatened. Here we address these statements by analyzing and projecting growth responses to climate of three major tree species (silver fir, Abies alba; Scots pine, Pinus sylvestris, and mountain pine, Pinus uncinata) in mountainous areas of NE Spain. This region is subjected to Mediterranean continental conditions, it encompasses wide climatic, topographic and environmental gradients, and, more importantly, it includes rear-edges of the continuous distributions of these tree species...
October 26, 2016: Global Change Biology
Y-F Ma, C Yuan, W-C Jiang, X-L Wang, P Humbert
BACKGROUND: Nowadays, the diagnosis for sensitive skin relies on subjective assessment or on the combination of subjective and objective evaluation. No quantitative evaluation is available. It could be expected that confocal microscopy imaging could be of interest to better define the condition. METHODS: Total 166 healthy female subjects were recruited in this study. Firstly, all subjects completed the sensitive questionnaire. Then, the cutaneous structures were measured by the reflectance confocal microscopy (RCM) on the face and fossa cubitalia...
October 26, 2016: Skin Research and Technology
A Sagar, Venkata Nagarjuna Babu, Anand H Shinde, Duddu S Sharada
A reactive cyclic iminium induced one-pot Groebke-Blackburn-Bienayme (GBB) double annulation cascade (DAC) for the synthesis of skeletally diverse DHIQ salts has been described. The key features of this protocol are transition-metal and solvent-free, mild reaction conditions, robust method, one-step construction of two privileged heterocyclic rings, clean reaction profile and operational simplicity.
October 26, 2016: Organic & Biomolecular Chemistry
Otome E Okoromoba, Zhou Li, Nicole Robertson, Mark S Mashuta, Uenifer R Couto, Cláudio F Tormena, Bo Xu, Gerald B Hammond
We developed an efficient fluorination protocol that converts easily accessible aziridines into β-fluoroamines, which are important motifs in biologically active molecules. In contrast with traditional fluorination approaches, DMPU-HF has shown both higher reactivity and regioselectivity and good functional group tolerance; thus, a wide scope of β-fluoroamines can now be accessed conveniently. The stereochemical behavior of the ring opening depends on the substitution pattern of the aziridine substrate.
October 26, 2016: Chemical Communications: Chem Comm
Suman Mallick, Kaushik Pal, Falguni Chandra, Apurba L Koner
Host-guest complexation of mono and dicationic quinine with cucurbit[7]uril (CB7), a water-soluble macrocyclic host molecule, has been investigated. Job's plot, time-resolved anisotropy as well as concentration dependent NMR titration confirm the binding of two CB7 macrocycles with one quinine molecule. The binding affinity of dicationic quinine with CB7 is one order of magnitude higher than the binding constant of mono-cationic quinine. Such preferential binding results in one unit pKa shift in the ground-state of the quinoline ring...
October 26, 2016: Physical Chemistry Chemical Physics: PCCP
Romina Brasca, María C Onaindia, Héctor C Goicoechea, Arsenio Muñoz de la Peña, María J Culzoni
A method for the detection and quantitation of Hg2+ in aqueous samples by fluorescence spectroscopy is presented. It consists of a turn-on sensor developed by coupling Gold nanoparticles (AuNPs) with the rhodamine 6G derivative FC1, in which the response is generated by a mercury-induced ring-opening reaction. The AuNPs were included in order to improve the sensitivity of the method towards the analyte, maintaining its high selectivity. The method was validated in terms of linearity, precision and accuracy, and applied to the quantitation of Hg2+ in Milli-Q and tap water with and without spiked analyte...
October 6, 2016: Sensors
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