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chemical shift

Aaron M Marcella, Sannie J Culbertson, Michael A Shogren-Knaak, Adam W Barb
The Escherichia coli holo-(acyl carrier protein) synthase (ACPS) catalyzes the coenzyme A-dependent activation of apo-ACPP to generate holo-(acyl carrier protein) (holo-ACPP) in an early step of fatty acid biosynthesis. E. coli ACPS is sufficiently different from the human fatty acid synthase to justify the development of novel ACPS-targeting antibiotics. Models of E. coli ACPS in unliganded and holo-ACPP-bound forms solved by X-ray crystallography to 2.05Å and 4.10Å, respectively, revealed ACPS bound three product holo-ACPP molecules to form a 3:3 hexamer...
October 17, 2017: Journal of Molecular Biology
Lorenzo Lazzaro, Giuseppe Mazza, Giada d'Errico, Arturo Fabiani, Claudia Giuliani, Alberto F Inghilesi, Alessandra Lagomarsino, Silvia Landi, Lorenzo Lastrucci, Roberta Pastorelli, Pio Federico Roversi, Giulia Torrini, Elena Tricarico, Bruno Foggi
Biological invasions are a global threat to biodiversity. Since the spread of invasive alien plants may have many impacts, an integrated approach, assessing effects across various ecosystem components, is needed for a correct understanding of the invasion process and its consequences. The nitrogen-fixing tree Robinia pseudoacacia (black locust) is a major invasive species worldwide and is used in forestry production. While its effects on plant communities and soils are well known, there have been few studies on soil fauna and microbes...
October 17, 2017: Science of the Total Environment
T Kirchgesner, V Perlepe, N Michoux, A Larbi, B Vande Berg
PURPOSE: To compare the effectiveness of fat suppression and the image quality of the Dixon method with those of the chemical shift-selective (CHESS) technique in hands of normal subjects at non-enhanced three-dimensional (3D) T1-weighted MR imaging. MATERIALS AND METHODS: Both hands of 14 healthy volunteers were imaged with 3D fast spoiled gradient echo (FSPGR) T1-weighted Dixon, 3D FSPGR T1-weighted CHESS and 3D T1-weighted fast spin echo (FSE) CHESS sequences in a 1...
October 17, 2017: Diagnostic and Interventional Imaging
Eric J Esswein, Marissa Alexander-Scott, John Snawder, Michael Breitenstein
Diesel engines serve many purposes in modern oil and gas extraction activities. Diesel particulate matter (DPM) emitted from diesel engines is a complex aerosol that may cause adverse health effects depending on exposure dose and duration. This study reports on personal breathing zone (PBZ) and area measurements for DPM (expressed as elemental carbon) during oil and gas extraction operations including drilling, completions (which includes hydraulic fracturing) and servicing work. Researchers at the National Institute for Occupational Safety and Health (NIOSH) collected 104 full-shift air samples (49 PBZ and 55 area) in Colorado, North Dakota, Texas, and New Mexico during a four year period from 2008-2012 The arithmetic mean (AM) of the full shift TWA PBZ samples was 10 µg/m(3); measurements ranged from 0...
October 20, 2017: Journal of Occupational and Environmental Hygiene
Na Kyung Kwon, Tae Kyung Lee, Sang Kyu Kwak, So Youn Kim
Localized surface plasmon resonance (LSPR) effect relies on the shape, size, and dispersion state of metal nanoparticles and can potentially be employed in many applications such as chemical/biological sensor, optoelectronics, and photocatalyst. While complicated synthetic approaches changing shape and size of nanoparticles can control the intrinsic LSPR effect, here we show that controlling interparticle interactions with silica-coated gold nanoparticles (Au@SiO2 NPs) is a powerful approach, permitting wide range of optical bandwidth of gold nanoparticles with great stability...
October 20, 2017: ACS Applied Materials & Interfaces
Simar J Singh, William Turner, Drew E Glaser, Kara E McCloskey, Fabian V Filipp
BACKGROUND: Vascular progenitor cells (VPCs) derived from embryonic stem cells (ESCs) are a valuable source for cell- and tissue-based therapeutic strategies. During the optimization of endothelial cell (EC) inductions from mouse ESCs using our staged and chemically-defined induction methods, we found that cell seeding density but not VEGF treatment between 10 ng/mL and 40 ng/mL was a significant variable directing ESCs into FLK1(+) VPCs during stage 1 induction. Here, we examine potential contributions from cell-to-cell signaling or cellular metabolism in the production of VPCs from ESCs seeded at different cell densities...
October 20, 2017: Cell Communication and Signaling: CCS
Peng Wang, Xue Jiang, Jun Hu, Jijun Zhao
Continuous miniaturization of magnetic units in spintronics devices inspires efforts to search for novel 2D magnetic materials with giant magnetic anisotropy energy (MAE). Through systematic first-principles calculations, large MAE of 24 meV in W or Re embedded 2D polyporphyrin frameworks is found. Interestingly, the MAE can be enhanced up to 60 meV, through replacing the hydrogen atoms on the edges of the Re based 2D polyporphyrin framework by hydroxyl and amino radicals. Analysis of the electronic structures reveals that the enhancement of MAE is mainly attributed to charge redistributions and energy shifts of Re 5d orbitals induced by the functional radicals...
October 2017: Advanced Science (Weinheim, Baden-Wurttemberg, Germany)
Karl Kaiser, Maria Canedo-Oropeza, Rachel McMahon, Rainer M W Amon
Arctic river watersheds are important components of the global climate system and show an amplified response to climate change. Here, we characterize origins and transformations of dissolved organic matter (DOM) in five major Arctic rivers (Kolyma, Lena, Yenisei, Ob, Mackenzie) over 3 years with seasonal sampling periods using measurements of carbohydrates, amino acids, bacterial biomarkers (D-amino acids), and plant protein biomarkers (hydroxyproline). A strong seasonal cycle of bioavailable DOM export was observed that correlated with discharge, vegetation, river morphology and water residence time...
October 19, 2017: Scientific Reports
I B Obot, Ikenna B Onyeachu, A Madhan Kumar
Sodium alginate (SA), a polysaccharide biopolymer, has been studied as an effective inhibitor against the corrosion of API X60 steel in neutral 3.5% NaCl using gravimetric and electrochemical techniques (OCP, EIS and EFM). The inhibition efficiency of the SA increased with concentration but was lower at higher temperature (70°C). Electrochemical measurements showed that the SA shifted the steel corrosion potential to more positive value and reduced the kinetics of corrosion by forming an adsorbed layer which mitigated the steel surface wetting, based on contact angle measurement...
December 15, 2017: Carbohydrate Polymers
Jing Dai, Zahra Alaei, Beatrice Plazzotta, Jan Skov Pedersen, Istvan Furo
By combining NMR (yielding 1H chemical shift, spin relaxation and self-diffusion data) and SAXS experiments, we investigate the complex temperature dependence of the molecular and aggregate states in aqueous solutions of the surfactant [CH3(CH2)17(OCH2CH2)20OH], abbreviated C18E20, and hexamethyldisiloxane HMDSO. The latter molecule serves as a model for hydrophobic solubilizates. Previously, the pure micellar solution was demonstrated to exhibit core freezing at approx. 7-8 °C. At room temperature, we find that HMDSO solubilizes at a volume fraction of approx...
October 20, 2017: Journal of Physical Chemistry. B
Yan-Jie Shi, Xiao-Ting Li, Xiao-Yan Zhang, Yu-Liang Liu, Lei Tang, Ying-Shi Sun
The retrospective study investigated accuracy of quantitative evaluation of T1-weighted imaging (T1WI) with and without fat suppression (FS), chemical-shift, diffusion-weighted imaging (DWI) and enhanced imaging at 3.0 T MRI for distinguishing spinal hemangiomas from metastases. 27 patients with 33 spinal hemangiomas (15 atypical hemangiomas) and 26 patients with 71 metastases were recruited. T1WI, FS T1WI, in- and out-phase, DWI and enhanced T1WI were acquired. Signal intensities (SIs) of lesions were obtained...
September 19, 2017: Oncotarget
Dieter Vollhardt, Gerald Brezesinski, Rainer Rudert, Antonio Gonzalez
The influence of the position of the aliphatic chain at the glycerol backbone has been basically unknown. Solely the results of 2-monopalmitoyl-rac-glycerol obtained at ≥13 °C indicated an essential influence of the position of the palmitoyl group at the glycerol backbone, substantiated by a disordered packing of the alkyl chains. Therefore, the present study extends the comprehensive characterization of 2-monopalmitoyl-rac-glycerol monolayers to the low temperature range for highlighting the effect of the position of the aliphatic chain at the glycerol backbone of monoalkanoylglycerolester monolayers...
October 19, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
Pallavi Singh, D Kar Chowdhuri
Increased oxidative stress is one of the major causes of hexavalent chromium [Cr(VI)], a heavy metal with diverse applications and environmental presence, induced neuronal adversities in exposed organism including Drosophila. Sestrin (sesn), an oxidative stress responsive gene, emerges as a novel player in the management of oxidative stress response. It is reported to be regulated by Target of rapamycin (TOR) and the former regulates autophagy and plays an important role in the prevention of neurodegeneration...
October 7, 2017: Chemosphere
Minakshi Ghate, H K Dahule, N Thejo Kalyani, S J Dhoble
A novel blue luminescent 6-chloro-2-(4-cynophenyl) substituted diphenyl quinoline (Cl-CN DPQ) organic phosphor has been synthesized by the acid-catalyzed Friedlander reaction and then characterized to confirm structural, optical and thermal properties. Structural properties of Cl-CN-DPQ were analyzed by Fourier transform infrared (FTIR), nuclear magnetic resonance (NMR) spectroscopy, X-ray diffraction technique (XRD) and scanning electron microscopy (SEM) and energy dispersive analysis of X-ray (EDAX) spectroscopy...
October 18, 2017: Luminescence: the Journal of Biological and Chemical Luminescence
Chih-Hung Chou, Basker Rajagopal, Chien-Fu Liang, Kuan-Lin Chen, Dun-Yuan Jin, Hsing-Yin Chen, Hsiu-Chung Tu, Yo-Ying Shen, Po-Chiao Lin
In this study, a series of variously substituted 2,3-dihydroquinolin-4-imines (DQIs) were synthesized from N-substituted propargylanilines by copper(I)-catalyzed annulation. The approach adopted in this study under mild, effective conditions exhibited broad substrate tolerance, particularly for functional groups substituted on anilines. Most of the DQI derivatives synthesized under optimal conditions were obtained in good isolated yields of 63-88%. 2,3-Dihydroquinolinimine thus obtained was easily converted to important structures like 2,3-dihydroquinolone and tetrahydrobenzodiazepin-5-one, confirming the importance of this strategy in constructing various heterocycles...
October 18, 2017: Chemistry: a European Journal
Abubakr Eldirdiri, Andreas Clemmensen, Sean Bowen, Andreas Kjaer, Jan Henrik Ardenkjaer-Larsen
A co-polarization scheme for [1,4-(13) C2 ]fumarate and [1-(13) C]pyruvate is presented to simultaneously assess necrosis and metabolism in rats with hyperpolarized (13) C magnetic resonance (MR). The co-polarization was performed in a SPINlab polarizer. In addition, the feasibility of simultaneous positron emission tomography (PET) and MR of small animals with a clinical PET/MR scanner is demonstrated. The hyperpolarized metabolic MR and PET was demonstrated in a rat model of necrosis. The polarization and T1 of the co-polarized [1,4-(13) C2 ]fumarate and [1-(13) C]pyruvate substrates were measured in vitro and compared with those obtained when the substrates were polarized individually...
October 18, 2017: NMR in Biomedicine
Biju Basumatary, Jyoti Rai, R V Ramana Reddy, Jeyaraman Sankar
One-electron oxidation of a Ga(III)-corrole with N(4-BrC6H4)3SbCl6 resulted in an air-stable non-innocent Ga(III)-corrole radical. Single crystal X-ray crystallography of 1,18-bisformyl[(TPFC)Ga(III)-Cl]* revealed delocalization of the unpaired electron, which was further confirmed by electron spin resonance (ESR) spectroscopy and spin density distribution plot. In addition, the nucleus-independent chemical shift (NICS), anisotropy induced-current density (AICD) and harmonic oscillator model of aromaticity (HOMA) supported a [17] pi-electron conjugated (or antiaromatic) radical...
October 18, 2017: Chemistry: a European Journal
Davy Sinnaeve
2D J-resolved spectroscopy is one of the oldest and conceptually most elegant ways to separate homonuclear scalar couplings from chemical shift information. In practice, the classical experiment suffers from a number of complications that limits accuracy and resolution, including phasetwist lineshapes, strong coupling artifacts and the need for shearing the spectrum by 45° to obtain a (J,δ)-representation. Here, a novel pure shift 2DJ experiment based on the TSE-PSYCHE experiment is reported that deals with all these issues...
October 16, 2017: Magnetic Resonance in Chemistry: MRC
Przemysław Krawczyk, Beata Jędrzejewska, Piotr Cysewski, Tomasz Janek
In this study, a new oxazolone derivative 4-{N,N-bis[2-phenyl-4-benzylidene-1,3-oxazol-5(4H)-one]amino}benzaldehyde (PB3) was synthesized and investigated as a fluorescent dye. The spectroscopic properties in different solvents were thoroughly studied. The experimental data were supported by quantum-chemical calculations using density functional theory. Measurements and theoretical calculations showed that the PB3 dye is characterized by non-monotonic solvatochromism, a strongly polar charge transfer excited state, a large Stokes' shift, a high fluorescence quantum yield and a high fluorescence lifetime...
October 18, 2017: Organic & Biomolecular Chemistry
Raphael J Eberle, Liege A Kawai, Fabio R de Moraes, Ljubica Tasic, Raghuvir K Arni, Monika A Coronado
Glutaredoxin A1 from Corynebacterium pseudotuberculosis was shown to be a mycoredoxin protein. In this study, we established a process to overexpress and purify glutaredoxin A1. The aim of this study was the investigation of the Glutaredoxin A1 from C. pseudotuberculosis behavior under different redox environments and the identification of lead molecules, which can be used for specific inhibitor development for this protein family. A quantitative assay was performed measuring the rate of insulin reduction spectrophotometrically at 640nm through turbidity formation from the precipitation of the free insulin...
October 14, 2017: International Journal of Biological Macromolecules
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