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Magnetic Nuclear Resonance

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https://www.readbyqxmd.com/read/28106743/design-synthesis-and-antifungal-activity-evaluation-of-new-thiazolin-4-ones-as-potential-lanosterol-14%C3%AE-demethylase-inhibitors
#1
Anca Stana, Dan C Vodnar, Radu Tamaian, Adrian Pîrnău, Laurian Vlase, Ioana Ionuț, Ovidiu Oniga, Brînduşa Tiperciuc
Twenty-three thiazolin-4-ones were synthesized starting from phenylthioamide or thiourea derivatives by condensation with α-monochloroacetic acid or ethyl α-bromoacetate, followed by substitution in position 5 with various arylidene moieties. All the synthesized compounds were physico-chemically characterized and the IR (infrared spectra), ¹H NMR (proton nuclear magnetic resonance), (13)C NMR (carbon nuclear magnetic resonance) and MS (mass spectrometry) data were consistent with the assigned structures...
January 17, 2017: International Journal of Molecular Sciences
https://www.readbyqxmd.com/read/28106742/mechanochemical-lignin-mediated-strecker-reaction
#2
Saumya Dabral, Mathias Turberg, Andrea Wanninger, Carsten Bolm, José G Hernández
A mechanochemical Strecker reaction involving a wide range of aldehydes (aromatic, heteroaromatic and aliphatic), amines, and KCN afforded a library of α-aminonitriles upon mechanical activation. This multicomponent process was efficiently activated by lignocellulosic biomass as additives. Particularly, commercially available Kraft lignin was found to be the best activator for the addition of cyanide to the in situ formed imines. A comparative study of the (31)P-NMR (Nuclear Magnetic Resonance) along with IR (Infrared) data analysis for the Kraft lignin and methylated Kraft lignin samples ascertained the importance of the free hydroxyl groups in the activation of the mechanochemical reaction...
January 17, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/28104838/distortion-of-histone-octamer-core-promotes-nucleosome-mobilization-by-a-chromatin-remodeler
#3
Kalyan K Sinha, John D Gross, Geeta J Narlikar
Adenosine 5'-triphosphate (ATP)-dependent chromatin remodeling enzymes play essential biological roles by mobilizing nucleosomal DNA. Yet, how DNA is mobilized despite the steric constraints placed by the histone octamer remains unknown. Using methyl transverse relaxation-optimized nuclear magnetic resonance spectroscopy on a 450-kilodalton complex, we show that the chromatin remodeler, SNF2h, distorts the histone octamer. Binding of SNF2h in an activated ATP state changes the dynamics of buried histone residues...
January 20, 2017: Science
https://www.readbyqxmd.com/read/28104837/the-role-of-dimer-asymmetry-and-protomer-dynamics-in-enzyme-catalysis
#4
Tae Hun Kim, Pedram Mehrabi, Zhong Ren, Adnan Sljoka, Christopher Ing, Alexandr Bezginov, Libin Ye, Régis Pomès, R Scott Prosser, Emil F Pai
Freeze-trapping x-ray crystallography, nuclear magnetic resonance, and computational techniques reveal the distribution of states and their interconversion rates along the reaction pathway of a bacterial homodimeric enzyme, fluoroacetate dehalogenase (FAcD). The crystal structure of apo-FAcD exhibits asymmetry around the dimer interface and cap domain, priming one protomer for substrate binding. This asymmetry is dynamically averaged through conformational exchange on a millisecond time scale. During catalysis, the protomer conformational exchange rate becomes enhanced, the empty protomer exhibits increased local disorder, and water egresses...
January 20, 2017: Science
https://www.readbyqxmd.com/read/28104795/magnetic-resonance-spectroscopy-of-an-atomically-thin-material-using-a-single-spin-qubit
#5
I Lovchinsky, J D Sanchez-Yamagishi, E K Urbach, S Choi, S Fang, T I Andersen, K Watanabe, T Taniguchi, A Bylinskii, E Kaxiras, P Kim, H Park, M D Lukin
Two-dimensional (2D) materials offer a promising platform for exploring condensed matter phenomena and developing technological applications. However, the reduction of material dimensions to the atomic scale poses a challenge for traditional measurement and interfacing techniques that typically couple to macroscopic observables. We demonstrate a method for probing the properties of 2D materials via nanometer-scale nuclear quadrupole resonance (NQR) spectroscopy using individual atom-like impurities in diamond...
January 19, 2017: Science
https://www.readbyqxmd.com/read/28104558/composition-and-copper-binding-properties-of-aquatic-fulvic-acids-in-eutrophic-taihu-lake-china
#6
Weiwei Li, Fenfen Zhang, Qi Ye, Dan Wu, Liying Wang, Yihua Yu, Bing Deng, Jinzhou Du
Fulvic acid (FA) plays a significant role in biogenic-elemental cycling in aquatic ecosystems which is highly dependent on their organic composition. In this study, the aquatic FA contents and binding properties during bloom and non-bloom periods in Taihu Lake were investigated by two-dimensional correlation spectroscopy Fourier transform infrared spectroscopy (2D-COS-FTIR), nuclear magnetic resonance (NMR) and elemental analysis. Compared with non-bloom FA, bloom FA was of lower nitrogen content and higher C/N ratio...
January 4, 2017: Chemosphere
https://www.readbyqxmd.com/read/28104248/continuous-hemifacial-myokymia-as-the-revealing-symptom-of-demyelinating-disease-of-the-cns
#7
Frédéric London, Nawal Hadhoum, Hélène Zéphir, Patrick Vermersch, Olivier Outteryck
Facial myokymia (FM) is an uncommon involuntary movement, disorder of the musculature supplied by the facial nerve and, characterized by spontaneous undulating, vermicular movements beneath the, skin. It has rarely been described as a form of presentation of multiple, sclerosis. We describe a 31-year-old man presenting with continuous, unilateral facial myokymia as the revealing symptom of a demyelinating, disorder of central nervous system. Brain magnetic resonance imaging, showed an ipsilateral pontine T2/FLAIR hyperintensity close to the, postgenu course of facial nerve, suggestive of a segmental demyelination, of facial nerve causing facial nuclear hyperactivity and resulting in FM...
January 2017: Multiple Sclerosis and related Disorders
https://www.readbyqxmd.com/read/28103873/masquelier-s-grape-seed-extract-from-basic-flavonoid-research-to-a-well-characterized-food-supplement-with-health-benefits
#8
REVIEW
Antje R Weseler, Aalt Bast
Careful characterization and standardization of the composition of plant-derived food supplements is essential to establish a cause-effect relationship between the intake of that product and its health effect. In this review we follow a specific grape seed extract containing monomeric and oligomeric flavan-3-ols from its creation by Jack Masquelier in 1947 towards a botanical remedy and nutraceutical with proven health benefits. The preparation's research history parallels the advancing insights in the fields of molecular biology, medicine, plant and nutritional sciences during the last 70 years...
January 19, 2017: Nutrition Journal
https://www.readbyqxmd.com/read/28103782/structures-of-the-first-extracellular-domain-of-crf-receptors
#9
Viviane Zelenay, Marilyn Perrin, Roland Riek
Corticotropin releasing factor (CRF) receptors belong to the secretin family of G protein-coupled receptors (GPCRs) and are responsible for initiating endocrine stress responses and mediating anxiety related behaviors upon activation via stressors. The main binding site for the CRF ligands is the first extracellular domain (ECD) of the receptors. Several structures of ligand-free and ligand-bound ECDs were recently determined either by nuclear magnetic resonance (NMR) spectroscopy or X-ray crystallography. They reveal how the ligands bind through both hydrophobic and hydrophilic interactions to the ECDs, which is highly dynamic in absence of ligands...
January 10, 2017: Current Molecular Pharmacology
https://www.readbyqxmd.com/read/28103047/anionic-head-containing-oxacalix-2-arene-2-triazines-synthesis-and-anion-%C3%AF-directed-self-assembly-in-solution-and-solid-state
#10
Rui-Bin Xu, Qi-Qiang Wang, Yu-Fei Ao, Zhi-Yan Li, Zhi-Tang Huang, De-Xian Wang
A series of oxacalix[2]arene[2]triazines bearing one anionic head such as carboxylate, sulfonate, sulfate, and phosphate were synthesized. With the anionic head and complementary V-shape electron-deficient cavity, these macrocycles can serve as dual building units, and their anion-π directed self-assembly was investigated. The formation of oligomeric aggregates in solution was revealed by nuclear magnetic resonance, dynamic light scattering, and mass spectroscopy. Crystal structures further confirmed chainlike assembly formation directed by anion-π interactions...
January 19, 2017: Organic Letters
https://www.readbyqxmd.com/read/28103036/paramagnetic-enhancement-of-nuclear-spin-spin-coupling
#11
Peter John Cherry, Syed Awais Rouf, Juha Vaara
We present a derivation and computations of the paramagnetic enhancement of the nuclear magnetic resonance (NMR) spin-spin coupling, which may be expressed in terms of the hyperfine coupling (HFC) and (for systems with multiple unpaired electrons) zero-field splitting (ZFS) tensors. This enhancement is formally analogous to the hyperfine contributions to the NMR shielding tensor as formulated by Kurland and McGarvey. The significance of the spin-spin coupling enhancement is demonstrated by using a combination of density-functional theory and correlated ab initio calculations, to determine the HFC and ZFS tensors, respectively, for two paramagnetic 3d metallocenes, a Cr(II)(acac) 2 complex, a Co(II) pyrazolylborate complex, and a lanthanide system, Gd-DOTA...
January 19, 2017: Journal of Chemical Theory and Computation
https://www.readbyqxmd.com/read/28102735/bulk-immunoassays-for-analysis-of-extracellular-vesicles
#12
Frank A W Coumans, Elmar L Gool, Rienk Nieuwland
There is increasing clinical interest in extracellular vesicles (EV) for diagnostic and treatment purposes. This review provides an overview of bulk immunoassays to analyse EV. Western blot and enzyme-linked immunosorbent assay are still the two predominant bulk immunoassays. Recently, new assays have become available that can detect exposure to EV concentrations that are up to 10,000-fold lower. This is advantageous for applications that detect rare EV. Other important parameters are the detectable concentration range, the required sample volume, whether simultaneous presence of different antigens on a single EV can be detected, size selectivity of each assay and practical considerations...
January 19, 2017: Platelets
https://www.readbyqxmd.com/read/28102680/ionicity-of-protic-ionic-liquid-quantitative-measurement-by-spectroscopic-methods
#13
Minming Shen, Yuyang Zhang, Kaizhou Chen, Siying Che, Jia Yao, Haoran Li
The ionicity value, which is a key property of protic ionic liquids, was obtained by the attenuated total reflection Fourier transform infrared spectroscopy and nuclear magnetic resonance respectively for a protic ionic liquid: n-propylammonium acetate. The method of potentiometric titration is found not suitable for such kind of ionic liquid as the ∆pKa of the compositing acid and base is relatively small. In the IR spectrum, molecular species can be directly observed in the range 1200-1800 cm-1, and the ratio of ionic and molecular species can be quantitatively calculated by the area of characteristic absorption peaks calibrated by standard curve from NaAc/HAc solutions...
January 19, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/28102665/cosolute-and-crowding-effects-on-a-side-by-side-protein-dimer
#14
Alex J Guseman, Gary J Pielak
The effects of small (~102 Da) and larger (>103 Da) cosolutes on protein stability are broadly understood: excluding volume stabilizes proteins, and chemical interactions are stabilizing when repulsive, but destabilizing when attractive. Proteins, however, rarely work alone. Here, we investigate the effects of small and larger cosolutes on the equilibrium stability of the simplest defined protein-protein interactions, the side-by-side homodimer formed by the A34F variant of the 56-residue B1 domain of protein G...
January 19, 2017: Biochemistry
https://www.readbyqxmd.com/read/28100626/effect-of-metformin-on-metabolites-and-relation-with-myocardial-infarct-size-and-left-ventricular-ejection-fraction-after-myocardial-infarction
#15
Ruben N Eppinga, Daniel Kofink, Robin P F Dullaart, Geertje W Dalmeijer, Erik Lipsic, Dirk J van Veldhuisen, Iwan C C van der Horst, Folkert W Asselbergs, Pim van der Harst
BACKGROUND: Left ventricular ejection fraction (LVEF) and infarct size (ISZ) are key predictors of long-term survival after myocardial infarction (MI). However, little is known about the biochemical pathways driving LV dysfunction after MI. To identify novel biomarkers predicting post-MI LVEF and ISZ, we performed metabolic profiling in the GIPS-III randomized clinical trial (Glycometabolic Intervention as Adjunct to Primary Percutaneous Intervention in ST Elevation Myocardial Infarction)...
February 2017: Circulation. Cardiovascular Genetics
https://www.readbyqxmd.com/read/28098776/distinguishing-benign-from-malignant-pancreatic-and-periampullary-lesions-using-combined-use-of-%C3%A2-h-nmr-spectroscopy-and-gas-chromatography-mass-spectrometry
#16
Yarrow J McConnell, Farshad Farshidfar, Aalim M Weljie, Karen A Kopciuk, Elijah Dixon, Chad G Ball, Francis R Sutherland, Hans J Vogel, Oliver F Bathe
Previous work demonstrated that serum metabolomics can distinguish pancreatic cancer from benign disease. However, in the clinic, non-pancreatic periampullary cancers are difficult to distinguish from pancreatic cancer. Therefore, to test the clinical utility of this technology, we determined whether any pancreatic and periampullary adenocarcinoma could be distinguished from benign masses and biliary strictures. Sera from 157 patients with malignant and benign pancreatic and periampullary lesions were analyzed using proton nuclear magnetic resonance (¹H-NMR) spectroscopy and gas chromatography-mass spectrometry (GC-MS)...
January 13, 2017: Metabolites
https://www.readbyqxmd.com/read/28098763/new-abietane-and-kaurane-type-diterpenoids-from-the-stems-of-tripterygium-regelii
#17
Dongsheng Fan, Shuangyan Zhou, Zhiyuan Zheng, Guo-Yuan Zhu, Xiaojun Yao, Ming-Rong Yang, Zhi-Hong Jiang, Li-Ping Bai
Eleven new abietane type (1‒11), and one new kaurane (12), diterpenes, together with eleven known compounds (13-23), were isolated and identified from the stems of Tripterygium regelii, which has been used as a traditional folk Chinese medicine for the treatment of rheumatoid arthritis in China. The structures of new compounds were characterized by means of the interpretation of high-resolution electrospray ionization mass spectrometry (HRESIMS), extensive nuclear magnetic resonance (NMR) spectroscopic data and comparisons of their experimental CD spectra with calculated electronic circular dichroism (ECD) spectra...
January 13, 2017: International Journal of Molecular Sciences
https://www.readbyqxmd.com/read/28098279/eu-3-doped-y3-xndxal3o12-garnet-synthesis-and-structural-investigation
#18
L Pavasaryte, A Katelnikovas, V Klimavicius, V Balevicius, A Krajnc, G Mali, J Plavec, A Kareiva
Nd(3+)-Doped yttrium aluminium garnet and Eu(3+)-Nd(3+)-co-doped yttrium aluminium garnet were synthesized using an environmentally friendly sol-gel method at low temperatures. The results of X-ray diffraction (XRD) analysis of the powders sintered at 1000 °C showed the purity and formation of monophasic compounds. The phase composition and purity confirmation of the samples were also characterized via FTIR spectroscopy. Desirable microstructural features and particle size of phosphorous materials of the polycrystalline samples were studied via scanning electron microscopy (SEM)...
January 18, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28098267/a-tailored-multi-frequency-epr-approach-to-accurately-determine-the-magnetic-resonance-parameters-of-dynamic-nuclear-polarization-agents-application-to-amupol
#19
P Gast, D Mance, E Zurlo, K L Ivanov, M Baldus, M Huber
To understand the dynamic nuclear polarization (DNP) enhancements of biradical polarizing agents, the magnetic resonance parameters need to be known. We describe a tailored EPR approach to accurately determine electron spin-spin coupling parameters using a combination of standard (9 GHz), high (95 GHz) and ultra-high (275 GHz) frequency EPR. Comparing liquid- and frozen-solution continuous-wave EPR spectra provides accurate anisotropic dipolar interaction D and isotropic exchange interaction J parameters of the DNP biradical AMUPol...
January 18, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28098142/carbon-translocation-from-a-plant-to-an-insect-pathogenic-endophytic-fungus
#20
Scott W Behie, Camila C Moreira, Irina Sementchoukova, Larissa Barelli, Paul M Zelisko, Michael J Bidochka
Metarhizium robertsii is a common soil fungus that occupies a specialized ecological niche as an endophyte and an insect pathogen. Previously, we showed that the endophytic capability and insect pathogenicity of Metarhizium are coupled to provide an active method of insect-derived nitrogen transfer to a host plant via fungal mycelia. We speculated that in exchange for this insect-derived nitrogen, the plant would provide photosynthate to the fungus. By using (13)CO2, we show the incorporation of (13)C into photosynthate and the subsequent translocation of (13)C into fungal-specific carbohydrates (trehalose and chitin) in the root/endophyte complex...
January 18, 2017: Nature Communications
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