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https://www.readbyqxmd.com/read/28644987/thiophene-thiazole-benzene-replacement-on-guanidine-derivatives-targeting-%C3%AE-2-adrenoceptors
#1
Aoife Flood, Cristina Trujillo, Goar Sanchez-Sanz, Brendan Kelly, Carolina Muguruza, Luis F Callado, Isabel Rozas
Searching for improved antagonists of α2-adrenoceptors, a thorough theoretical study comparing the aromaticity of phenyl-, pyridinyl-, thiophenyl- and thiazolylguanidinium derivatives has been carried out [at M06-2X/6-311++G(p,d) computational level] confirming that thiophene and thiazole will be good 'ring equivalents' to benzene in these guanidinium systems. Based on these results, a small but chemically diverse library of guanidine derivatives (15 thiophenes and 2 thiazoles) were synthesised to explore the effect that the bioisosteric change has on affinity and activity at α2-adrenoceptors in comparison with our previously studied phenyl derivatives...
June 6, 2017: European Journal of Medicinal Chemistry
https://www.readbyqxmd.com/read/28644917/an-oxygen-isotope-chronometer-for-cellulose-deposition-the-successive-leaves-formed-by-tillers-of-a-c4-perennial-grass
#2
Hai Tao Liu, Fang Yang, Xiao Ying Gong, Rudi Schäufele, Hans Schnyder
Multiannual time series of (palaeo)hydrological information can be reconstructed from the oxygen isotope composition of cellulose (δ(18) OCel ) in biological archives, e.g. tree-rings, but our ability to temporally resolve information at subannual scale is limited. We capitalized on the short and predictable leaf appearance interval (2.4 d) of a perennial C4 grass (Cleistogenes squarrosa), to assess its potential for providing highly time-resolved δ(18) OCel records of vapor pressure deficit (VPD). Plants grown at low (0...
June 23, 2017: Plant, Cell & Environment
https://www.readbyqxmd.com/read/28644909/a-highly-efficient-synthesis-of-z-macrocycles-using-stereoretentive-ruthenium-based-metathesis-catalysts
#3
Tonia Sarah Ahmed, Robert H Grubbs
A highly efficient, Z-selective ring-closing metathesis system for the formation of macrocycles using a stereoretentive, ruthenium-based catalyst supported by a dithiolate ligand is reported. This catalyst is demonstrated to be remarkably active as observed in initiation experiments showing complete catalyst initiation at -20 °C within 10 min. Macrocyclization reactions generated Z-products from easily accessible diene starting materials bearing a Z-olefin moiety. This stereoretentive approach provides a more efficient and selective route to Z-macrocyles than in previously reported systems...
June 23, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28644708/the-arabidopsis-mind-mutation-causes-aberrant-ftsz1-ring-placement-and-moderate-heterogeneity-of-chloroplasts-in-the-leaf-epidermis
#4
Makoto T Fujiwara, Mana Yasuzawa, Shun Sasaki, Takeshi Nakano, Yasuo Niwa, Shigeo Yoshida, Tomoko Abe, Ryuuichi D Itoh
Symmetric division of leaf mesophyll chloroplasts requires MinD and MinE, which work together to suppress division other than at the mid-chloroplast. arc11 is a MinD loss-of-function mutant of Arabidopsis thaliana. In arc11 plants, asymmetric chloroplast division, as well as its delay or arrest, results in extreme size polymorphism of chloroplasts in mature mesophyll cells. The current study examined chloroplast phenotypes in the epidermis of arc11 leaves. Fluorescence microscopy analysis revealed that epidermal chloroplasts in mature leaves exhibited moderate heterogeneity in size...
June 23, 2017: Plant Signaling & Behavior
https://www.readbyqxmd.com/read/28644686/cervical-adenocarcinoma-diagnosis-of-human-papillomavirus-positive-and-human-papillomavirus-negative-tumors
#5
Edyta C Pirog
CONTEXT: - Cervical adenocarcinomas span a diverse group of tumors with several distinct histologic tumor types, which include endocervical, endometrioid, intestinal, villoglandular, gastric, signet ring, serous, clear cell, and mesonephric. Diagnosis of cervical adenocarcinoma, especially early diagnosis, poses a significant challenge. OBJECTIVE: - To review the pathogenesis, diagnostic criteria, immunohistochemical markers, and differential diagnosis of various subtypes of human papillomavirus (HPV)-positive and HPV-negative cervical adenocarcinomas...
June 23, 2017: Archives of Pathology & Laboratory Medicine
https://www.readbyqxmd.com/read/28644616/importance-of-a-fully-anharmonic-treatment-of-equilibrium-isotope-fractionation-properties-of-dissolved-ionic-species-as-evidenced-by-li-aq
#6
Romain Dupuis, Magali Benoit, Mark E Tuckerman, Merlin Méheut
Equilibrium fractionation of stable isotopes is critically important in fields ranging from chemistry, including medicinal chemistry, electrochemistry, geochemistry, and nuclear chemistry, to environmental science. The dearth of reliable estimates of equilibrium fractionation factors, from experiment or from natural observations, has created a need for accurate computational approaches. Because isotope fractionation is a purely quantum mechanical phenomenon, exact calculation of fractionation factors is nontrivial...
June 23, 2017: Accounts of Chemical Research
https://www.readbyqxmd.com/read/28644576/size-dependency-of-tree-growth-response-to-drought-among-norway-spruce-and-european-beech-individuals-in-monospecific-and-mixed-species-stands
#7
Haiyu Ding, Hans Pretzsch, Gerhard Schütze, Thomas Rötzer
Climatic anomalies have resulted in changing forest productivity, increasing tree mortality in Central and Southern Europe. This has resulted in more severe and frequent ecological disturbances to the forest stands. This study analysed the size dependency of growth response to drought years based on 384 tree individuals of Norway spruce (Picea abies [L.] Karst.) and European beech (Fagus sylvatica [L.]) in Bavaria, Germany. Samples were collected in both monospecific and mixed-species stands. To quantify the growth response of drought stress, indices including basal area increment, resistance, recovery, and resilience were calculated from tree ring measurements of increment cores...
June 23, 2017: Plant Biology
https://www.readbyqxmd.com/read/28644563/gas-phase-dissociation-study-of-erythrinian-alkaloids-by-electrospray-ionization-mass-spectrometry-and-computational-methods
#8
T Guaratini, L G P Feitosa, D B Silva, N P Lopes, J L C Lopes, R Vessecchi
Alkaloids from plants of the genus Erythrina display important biological activities, including anxiolytic action. Characterization of these alkaloids by mass spectrometry (MS) has contributed to the construction of a spectral library, has improved understanding of their structures, and has supported the proposal of fragmentation mechanisms in light of density functional calculations (DFT). In this study, we have used low- and high-resolution MS(n) analyses to investigate the fragmentation patterns of erythrinian alkaloids; we have employed the B3LYP/6-31+G(d,p) model to obtain their reactive sites...
June 23, 2017: Journal of Mass Spectrometry: JMS
https://www.readbyqxmd.com/read/28644553/structural-insights-into-the-inclusion-complexes-between-clomiphene-citrate-and-%C3%AE-cyclodextrin-the-mechanism-of-preferential-isomeric-selection
#9
Arti Maheshwari, Harish Saraswat, Santosh Kumar Upadhyay
A major challenge in pharmaceuticals for clinical applications is to alter the solubility, stability, and toxicity of drug molecules in living systems. Cyclodextrins (CDs) have the ability to form host-guest inclusion complexes with pharmaceuticals for further development of new drug formulations. The inclusion complex of clomiphene citrate (CL), a poorly water-soluble drug, with native β-cyclodextrin (β-CD) was characterized by a one and two-dimensional nuclear magnetic resonance (NMR) spectroscopic approach and also by molecular docking techniques...
June 23, 2017: Chirality
https://www.readbyqxmd.com/read/28644528/a-systematic-1-h-and-13-c-nmr-spectral-analysis-of-bicyclo-n-3-1-alkanone-systems-determination-of-the-relative-configuration-of-the-stereogenic-centres-and-conformation-of-the-six-membered-ring
#10
Giorgio Giorgi, Pilar López-Alvarado, J Carlos Menéndez
No abstract text is available yet for this article.
June 23, 2017: Magnetic Resonance in Chemistry: MRC
https://www.readbyqxmd.com/read/28644240/corneal-stiffening-by-a-bacteriochlorophyll-derivative-with-dextran-and-near-infrared-light-effect-of-shortening-irradiation-time-up-to-1-minute
#11
Jurriaan Brekelmans, Alexandra Goz, Mor M Dickman, Alexander Brandis, Xiaomeng Sui, H Daniel Wagner, Rudy M M A Nuijts, Avigdor Scherz, Arie L Marcovich
PURPOSE: The aim of this study is to determine the effect of variation of the exposure time of near-infrared irradiation on corneal stiffening after a bacteriochlorophyll derivative (WST11) with dextran (WST-D) application. METHODS: One hundred four paired eyes of 3-month-old New Zealand White rabbits were included in this study. Fifty-two eyes (ex vivo n = 34, in vivo n = 18) were mechanically deepithelialized, treated topically with WST-D, and irradiated at 10 mW/cm using a diode laser at 755 nm for 1, 5, or 30 minutes...
June 21, 2017: Cornea
https://www.readbyqxmd.com/read/28644123/pin-malposition-in-external-fixator-stabilization-of-combat-related-pelvic-fractures
#12
Mark P Coseo, Dustin J Schuett, Kevin M Kuhn, Joseph Bellamy
The purpose of this study was to compare the accuracy of pin placement in patients with unstable pelvic fractures undergoing either iliac crest or supra-acetabular external fixation. A retrospective review was performed of computed tomography (CT) scans and injury characteristics for all patients presenting to a North Atlantic Treaty Organization Medical Treatment Facility with data entered into the Department of Defense Trauma Registry from January 2008 to October 2013 who underwent pelvic external fixation for unstable pelvic ring injuries...
2017: Journal of Surgical Orthopaedic Advances
https://www.readbyqxmd.com/read/28644017/spectrally-undiscerned-isomers-might-lead-to-erroneous-determination-of-water-exchange-rates-of-paracest-eu-iii-agents
#13
Nevenka Cakić, Ben Tickner, Moritz Zaiss, David Esteban-Gómez, Carlos Platas-Iglesias, Goran Angelovski
We report a detailed study of the solution structure and water exchange rate of a Eu(III) complex with the cyclen-based ligand L(1), containing (S)-2-(2-acetamido)-3-(4-(trifluoromethyl)phenyl)propanoate pendant arms at positions 1 and 7 of the cyclen ring and acetylglycinate pendants at positions 4 and 10. The EuL(1) complex was characterized by a combination of NMR and luminescence spectroscopy and density functional theory (DFT) calculations. The chemical exchange saturation transfer (CEST) spectra obtained at different temperatures and saturation powers present a CEST signal attributed to the coordinated water molecule...
June 23, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28643874/2-6-bis-diazaboryl-pyridine-a-superbasic-sterically-demanding-pyridine-ligand
#14
Tobias Böttcher, Daniel Himmel, Jan Schröder
Herein we present a convenient one-pot route to a sterically demanding superbasic pyridine. Functionalization of the 2,6-positions with the highly sigma-donating boryl-groups shifts the calculated gas phase basicity of the pyridine's nitrogen atom to 1012 kJ mol-1, which outperforms the 'proton sponge' 1,8-bis(dimethylamino)naphthalene (996 kJ mol-1). The diazaboryl groups are oriented orthogonal to the pyridine ring and do not block the N-position, resembling the geometry of commonly used N-heterocyclic carbenes...
June 23, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28643863/design-of-iron-ii-pthalocyanine-fepc-derived-oxygen-reduction-electrocatalysts-for-high-power-density-microbial-fuel-cells
#15
Carlo Santoro, Rohan Gokhale, Barbara Mecheri, Alessandra D'Epifanio, Silvia Licoccia, Alexey Serov, Kateryna Artyushkova, Plamen Atanassov
Iron(II) Phthalocyanine (FePc) deposited onto two different carbonaceous supports was synthesized by the non-conventional pyrolysis-free method, studied in the reaction of oxygen reduction (ORR) in neutral media, incorporated in an air-breathing cathode structure and tested in operating microbial fuel cell (MFC) configuration. Rotating ring disk electrode (RRDE) analysis revealed high performances of the Fe-based catalysts compared with activated carbon (AC). It was shown that Black Pearls supported FePc (Fe-BP(N)) exhibits the highest performance in term of more positive onset, positive shift of half-wave potential and higher limiting as well as highest power density in operating MFC (243±7 μWcm-2) that was 33% higher than Fe-CNT(N) (182±5 μWcm-2)...
June 23, 2017: ChemSusChem
https://www.readbyqxmd.com/read/28643859/gibberellic-and-kaurenoic-hybrid-strigolactone-mimics-for-seed-germination-of-parasitic-weeds
#16
Rondinelle G Pereira, Antonio Cala, Mónica Fernández-Aparicio, José M G Molinillo, Maria A D Boaventura, Francisco A Macías
BACKGROUND: Parasitic weeds are widespread and they cause significant losses in important crops. Their germination requires the detection of crop-derived molecules such as strigolactones. Strigolactone mimics are germination-inducing molecules with potential to apply the suicidal germination strategy for seed bank control of parasitic weeds. RESULTS: Attachment of the D-ring, which is instrumental in the germination process of seeds of parasitic weeds, has been carried out to gibberellin (GA3 ) and kaurenoic as the scaffold...
June 23, 2017: Pest Management Science
https://www.readbyqxmd.com/read/28643783/cdt1-stabilizes-an-open-mcm-ring-for-helicase-loading
#17
Jordi Frigola, Jun He, Kerstin Kinkelin, Valerie E Pye, Ludovic Renault, Max E Douglas, Dirk Remus, Peter Cherepanov, Alessandro Costa, John F X Diffley
ORC, Cdc6 and Cdt1 act together to load hexameric MCM, the motor of the eukaryotic replicative helicase, into double hexamers at replication origins. Here we show that Cdt1 interacts with MCM subunits Mcm2, 4 and 6, which both destabilizes the Mcm2-5 interface and inhibits MCM ATPase activity. Using X-ray crystallography, we show that Cdt1 contains two winged-helix domains in the C-terminal half of the protein and a catalytically inactive dioxygenase-related N-terminal domain, which is important for MCM loading, but not for subsequent replication...
June 23, 2017: Nature Communications
https://www.readbyqxmd.com/read/28643776/ezrin-enhances-line-tension-along-transcellular-tunnel-edges-via-nmiia-driven-actomyosin-cable-formation
#18
Caroline Stefani, David Gonzalez-Rodriguez, Yosuke Senju, Anne Doye, Nadia Efimova, Sébastien Janel, Justine Lipuma, Meng Chen Tsai, Daniel Hamaoui, Madhavi P Maddugoda, Olivier Cochet-Escartin, Coline Prévost, Frank Lafont, Tatyana Svitkina, Pekka Lappalainen, Patricia Bassereau, Emmanuel Lemichez
Transendothelial cell macroaperture (TEM) tunnels control endothelium barrier function and are triggered by several toxins from pathogenic bacteria that provoke vascular leakage. Cellular dewetting theory predicted that a line tension of uncharacterized origin works at TEM boundaries to limit their widening. Here, by conducting high-resolution microscopy approaches we unveil the presence of an actomyosin cable encircling TEMs. We develop a theoretical cellular dewetting framework to interpret TEM physical parameters that are quantitatively determined by laser ablation experiments...
June 23, 2017: Nature Communications
https://www.readbyqxmd.com/read/28643515/structures-of-degradation-products-and-degradation-pathways-of-aflatoxin-b1-by-high-voltage-atmospheric-cold-plasma-hvacp-treatment
#19
Hu Shi, Bruce R Cooper, Richard L Stroshine, Klein E Ileleji, Kevin Keener
High voltage atmospheric cold plasma (HVACP) is a novel non-thermal decontamination technology that has potential for use in the food industry. In this study, HVACP was applied to treat pure aflatoxin B1 (AFB1) powder on a glass slide. AFB1 was degraded by 76% using a 5 min HVACP treatment in air having 40% relative humidity. The degradation products of AFB1 were separated and their molecular formulas were elucidated using liquid chromatography time of flight mass spectrometry (HPLC-TOF MS). Six main degradation products were observed...
June 23, 2017: Journal of Agricultural and Food Chemistry
https://www.readbyqxmd.com/read/28643513/photochemical-cleavage-of-benzylic-c-o-bond-facilitated-by-an-ortho-or-meta-amino-group
#20
Xiong Ding, Pengfei Wang
The excited state meta effect, also known as the meta-ortho effect, results from selective electron transmission from an electron-donating group to the meta and ortho sites on an aromatic ring in its first excited singlet state. This effect facilitates photochemical cleavage of benzylic C-O or C-N bond to release the corresponding alcohol, carboxylic acid, or amine when an electron-donating amino group is at the meta position, as demonstrated in our recent work of using a 3-diethylaminobenzyl (DEABn) group as an effective photolabile protecting group (PPG)...
June 23, 2017: Journal of Organic Chemistry
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