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Andrew J Pell, Kevin J Sanders, Sebastian Wegner, Guido Pintacuda, Clare P Grey
We propose two broadband pulse schemes for (14)N solid-state magic-angle-spinning (MAS) nuclear magnetic resonance (NMR) that achieves (i) complete population inversion and (ii) efficient excitation of the double-quantum spectrum using low-power single-sideband-selective pulses. We give a comprehensive theoretical description of both schemes using a common framework that is based on the jolting-frame formalism of Caravatti et al. [J. Magn. Reson. 55, 88 (1983)]. This formalism is used to determine for the first time that we can obtain complete population inversion of (14)N under low-power conditions, which we do here using single-sideband-selective adiabatic pulses...
May 21, 2017: Journal of Chemical Physics
Theodore R Saitz, Solange Mongoue-Tchokote, Cynthia Sharadin, Dana W Giel, Sean Corbett, Larisa Kovacevic, Aaron P Bayne
INTRODUCTION: Specific factors associated with the risk of developing pediatric urinary stone disease remain unclear, especially those that may be associated with recurrent stone disease. OBJECTIVE: We compared the results of 24-h urine collections in children with a solitary stone episode to those with multiple stone episodes to determine if there is a difference that may be associated with multiple stone formation in children. STUDY DESIGN: A multi-institutional retrospective analysis was completed to assess 24-h urinary metabolic profiles in children with urolithiasis aged 2-18 years old...
April 20, 2017: Journal of Pediatric Urology
Jian Xie, Yaxing Wang, Wei Liu, Xuemiao Yin, Lanhua Chen, Youming Zou, Juan Diwu, Zhifang Chai, Thomas E Albrecht-Schmitt, Guokui Liu, Shuao Wang
Precise detection of low-dose X- and γ-radiations remains a challenge and is particularly important for studying biological effects under low-dose ionizing radiation, safety control in medical radiation treatment, survey of environmental radiation background, and monitoring cosmic radiations. We report here a photoluminescent uranium organic framework, whose photoluminescence intensity can be accurately correlated with the exposure dose of X- or γ-radiations. This allows for precise and instant detection of ionizing radiations down to the level of 10(-4)  Gy, representing a significant improvement on the detection limit of approximately two orders of magnitude, compared to other chemical dosimeters reported up to now...
May 19, 2017: Angewandte Chemie
Tatsiana Liavitskaya, Nathanaël Guigo, Nicolas Sbirrazzuoli, Sergey Vyazovkin
Following the previous work (Phys. Chem. Chem. Phys., 2016, 18, 32021), this study continues to investigate the intriguing phenomenon of thermal decomposition during continuous cooling. The phenomenon can be detected and its kinetics can be measured by means of thermogravimetric analysis (TGA). The kinetics of the thermal decomposition of ammonium nitrate (NH4NO3), nickel oxalate (NiC2O4), and lithium sulfate monohydrate (Li2SO4·H2O) have been measured upon heating and cooling and analyzed by means of the isoconversional methodology...
May 18, 2017: Physical Chemistry Chemical Physics: PCCP
Ji Xing, Maoying Liao, Chi Zhang, Min Yin, Dongdong Li, Ye Song
To investigate the effect of anions on the electrochemical properties of polyaniline (PANI) for supercapacitors, electrochemical performance tests of PANI with different dopant anions were carried out in the corresponding acid solutions by cyclic voltammetry (CV) and galvanostatic charge-discharge (GCD) methods. In particular, ionic fluxes and solvent molecules involved in redox processes can be analyzed by the electrochemical quartz crystal microbalance (EQCM) technique and discriminated by simultaneously recording cyclic voltammograms and mass changes during redox switching...
May 18, 2017: Physical Chemistry Chemical Physics: PCCP
Elizabeth Pierce, Steven O Mansoorabadi, Mehmet Can, George H Reed, Stephen W Ragsdale
Oxalate:ferredoxin oxidoreductase (OOR) is an unusual member of the thiamine pyrophosphate (TPP)-dependent 2-oxoacid:ferredoxin oxidoreductase (OFOR) family in that it catalyzes the coenzyme A (CoA)-independent conversion of oxalate into two moles of carbon dioxide. This reaction is surprising because binding of CoA to the acyl-TPP intermediate of other OFORs results in formation of a CoA ester and, in the case of pyruvate:ferredoxin oxidoreductase (PFOR), CoA binding generates the central metabolic intermediate acetyl-CoA and promotes a 10(5)-fold acceleration of the rate of electron transfer...
May 17, 2017: Biochemistry
Chin-Fa Lee, Chia-Wei Chen, Yi-Ling Chen, Daggula Mallikarjuna Reddy, Kai Du, Chao-En Li, Bo-Hao Shih, Yung-Jing Xue
We report a general copper-catalyzed cross-coupling of thiols with aryl bromides and aryl chlorides by using N-aryl-N'-alkyl oxalic diamide (L3) or N,N'-dialkyl oxalic diamide (L5) as the ligands. Remarkably, this is the first copper-catalyzed coupling of thiols with unactivated aryl chlorides. Furthermore, this system features broad substrate scope and good tolerance of functional groups. Importantly, the oxalic diamides are stable and can be prepared easily from commercially available cheap starting materials...
May 16, 2017: Chemistry: a European Journal
Bo Jiang, Shuaishuai Xin, Haihong He, Xuyang Liu, Li Gao, Yizheng Tang, Xuejun Bi
In this study, the photooxidation capacity of UVC/Oxalate (Ox) was evaluated using As(III) as a typical pollutant. The results show that the direct oxidation amount of As(III) induced by UVC in water was negligible, but the presence of Ox remarkably accelerated the oxidation rate of As(III). Under UVC irradiation, 50 μM As(III) can be completely oxidized to As(V) in the case of Ox concentration above 300 μM within 60 min. As(III) oxidation was found greatly related with the photodecomposition of Ox. Much more Ox can be mineralized in more acidic solution...
May 7, 2017: Chemosphere
Amin Golpour, Martin Pšenička, Hamid Niksirat
Calcium plays a variety of vital regulatory functions in many physiological and biochemical events in the cell. The aim of this study was to describe the ultrastructural distribution of calcium during different developmental stages of spermatogenesis in a model organism, the zebrafish (Danio rerio), using a combined oxalate-pyroantimonate technique. Samples were treated by potassium oxalate and potassium pyroantimonate during two fixation stages and examined using transmission electron microscopy to detect electron dense intracellular calcium...
May 14, 2017: Journal of Morphology
Anisa Ghogar, Wannee Jiraungkoorskul
Bougainvillea spectabilis (Family: Nyctaginaceae), commonly referred to as Great Bougainvillea or Paper Flower, is one of the traditional medicinal plants with potential antifertility activity. The aqueous extract and decoction of this plant have been used as fertility control among the tribal people in many countries. Furthermore, it has been shown to possess anticancer, antidiabetic, antihepatotoxic, anti-inflammatory, antihyperlipidemic, antimicrobial, antioxidant, and antiulcer properties. Its phytoconstituents such as alkaloids, essential oils, flavonoids, glycosides, oxalates, phenolics, phlobotannins, quinones, saponins, tannins, and terpenoids were reported as the basis of its efficacious therapeutic properties...
January 2017: Pharmacognosy Reviews
Tommaso Poli, Anna Piccirillo, Marco Nervo, Oscar Chiantore
The degradation process involving the formation of metal soaps in drying oils is a well-known problem due to cations from pigments reacting with free fatty acids from the oil. The aggregation of these carboxylates in semi-crystalline structures can lead to eruptions through the paint layers and 'blooming' on the surface. In this work, the metal soaps formation in presence of natural resins has been assessed and studied by means of Fourier transform infrared spectroscopy with experiments concerning the ageing of drying oil and different natural resins (shellac, dammar and colophony) in the presence of common historic pigments (smalt, ochre, umber, azurite, lead white, zinc white and titanium white)...
May 2, 2017: Journal of Colloid and Interface Science
Michael Charles Thompson, Leah G Dodson, J Mathias Weber
We present IR spectra and quantum chemical calculations for anionic iron-CO2 clusters of the form [Fe(CO2)n](-) (n = 3 - 7). All observed clusters have at least two strongly bound CO2 moieties as part of the core ion, and larger clusters show clear infrared signatures of core ion isomers with three CO2 moieties as well. Dominant structural motifs are based on bidentate CO2 ligands with Fe-O/Fe-C bonds, oxalate ligands and metal insertion into a CO bond.
May 12, 2017: Journal of Physical Chemistry. A
Gina Johnson, Jerad M Gardner, Sara C Shalin
Polarizable calcium oxalate (CaOx) crystals have been well documented in breast biopsies, generally associated with benign apocrine metaplasia. In contrast, polarizable crystals are only rarely reported in skin adnexal neoplasms. We report three different cases of sweat gland tumors with polarizable crystals morphologically suggestive of CaOx: 1 apocrine hidrocystoma and 2 tubular apocrine adenomas. The histologic features were examined in 3 cases. Clinical presentation summary included 2 males and 1 female, ages 53 to 74, with lesions located on the left cheek, inferior vertex scalp and the left eyebrow...
May 12, 2017: Journal of Cutaneous Pathology
Juthatip Manissorn, Kedsarin Fong-Ngern, Paleerath Peerapen, Visith Thongboonkerd
Urine pH has been thought to be an important factor that can modulate kidney stone formation. Nevertheless, there was no systematic evaluation of such pH effect. Our present study thus addressed effects of differential urine pH (4.0-8.0) on calcium oxalate (CaOx) crystallization, crystal-cell adhesion, crystal internalization into renal tubular cells, and binding of apical membrane proteins to the crystals. Microscopic examination revealed that CaOx monohydrate (COM), the pathogenic form, was crystallized with greatest size, number and total mass at pH 4...
May 11, 2017: Scientific Reports
Jingzi Beiyuan, Jiang-Shan Li, Daniel C W Tsang, Lei Wang, Chi Sun Poon, Xiang-Dong Li, Scott Fendorf
This study evaluated the feasibility of 2-h chemical-enhanced washing of As-containing soil resulting from geogenic sources in Hong Kong and the fate of As before and after remediation. The soil morphology and As speciation in soil was elucidated by scanning electron microscopy with energy dispersive X-ray spectroscopy, X-ray diffractometer, X-ray photoelectron spectroscopy, and X-ray absorption spectroscopy. Integrated analysis of the results suggests that the As (>90%) resides predominantly as arsenate bound to ferric iron oxides, with a minor contribution (<10%) from an As(III)-sulphide phase...
May 8, 2017: Science of the Total Environment
N Paßlack, J Zentek, J A Larsen, J L Westropp, A J Fascetti
Findings in humans and rats indicate that hyperlipidaemia may be associated with enhanced endogenous oxalate (Ox) synthesis, which may be relevant for calcium oxalate (CaOx) urolith formation. Moreover, changes in lipid metabolism are proposed to negatively affect gut microbiota. This study aimed to investigate those potential interactions in hyperlipidaemic cats. Therefore, 10 normal control cats and seven lipoprotein lipase (LPL)-deficient cats were fed a low-fat diet for seven weeks. During the last week of the study, cats were housed in metabolic cages to collect urine and faeces...
May 11, 2017: Journal of Animal Physiology and Animal Nutrition
Mustafa Kadihasanoglu, Ugur Yucetas, Mehmet Gokhan Culha, Erkan Erkan, Mahmut Gokhan Toktas
OBJECTIVE: To compare the effectiveness of laser lithotripsy (LL) and pneumatic lithotripters (PL) in calcium oxalate (CaOx) and calcium phosphate (CaP) stones and assess whether these stone compositions affect the outcomes of LL and PL. STUDY DESIGN: Comparative, descriptive study. PLACE AND DURATION OF STUDY: Istanbul Training and Research Hospital, Turkey, from August 2010 to August 2015. METHODOLOGY: A total of 114 patients underwent ureteroscopy using LL and PL...
April 2017: Journal of the College of Physicians and Surgeons—Pakistan: JCPSP
Yan-Ying Yan, Qing-An Zhang, Er-Chun Li, Ya-Feng Zhang
Change in electrical conductivity is considered a potential indicator for the on-line monitoring of wine aging accelerated by ultrasound, as determined in our previous study; however, the exact mechanism of change is currently unclear. In this study, the ion content and the total ionic strength were analyzed by ion-exchange chromatography to investigate the change mechanism of the electrical conductivity of wine under ultrasound irradiation. The results indicate that the changes in wine electrical conductivity during ultrasound treatment correlate with the changes in the cations (Na(+), K(+), Ca(2+), Mg(2+), and NH₄(+)) and in the anions from the organic acids (malic acid, citric acid, tartaric acid, oxalic acid, and formic acid) and inorganic acids (Cl(-), SO₄(2-), and PO₄(3-)), especially for the ionic strength of the wine...
May 11, 2017: Journal of AOAC International
Nathalie Demoulin, Zaina Issa, Ralph Crott, Johann Morelle, Etienne Danse, Pierre Wallemacq, Michel Jadoul, Pierre H Deprez
Chronic pancreatitis may lead to steatorrhea, enteric hyperoxaluria, and kidney damage. However, the prevalence and determinants of hyperoxaluria in chronic pancreatitis patients as well as its association with renal function decline have not been investigated.We performed an observational study. Urine oxalate to creatinine ratio was assessed on 2 independent random urine samples in consecutive adult patients with chronic pancreatitis followed at the outpatient clinic from March 1 to October 31, 2012. Baseline characteristics and annual estimated glomerular filtration rate (eGFR) change during follow-up were compared between patients with hyper- and normo-oxaluria...
May 2017: Medicine (Baltimore)
Husain N Kagalwala, Danielle N Chirdon, Isaac N Mills, Nikita Budwal, Stefan Bernhard
A unique microemulsion-based photocatalytic water reduction system is demonstrated. Iridium- and rhodium-based metallosurfactants, namely, [Ir(ppy)2(dhpdbpy)]Cl and [Rh(dhpdbpy)2Cl2]Cl (where ppy = 2-phenylpyridine and dhpdbpy = 4,4'-diheptadecyl-2,2'-bipyridine), were employed as photosensitizer and proton reducing catalyst, respectively, along with oxalic acid as a sacrificial reductant in a toluene/water biphasic mixture. The addition of 1-octylamine is proposed to initiate the reaction, by coupling with oxalic acid to form an ion pair, which acts as an additional surfactant...
May 10, 2017: Inorganic Chemistry
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