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https://www.readbyqxmd.com/read/28651024/short-term-proton-pump-inhibitor-treatment-may-cause-hypomagnesaemia-in-critically-ill-patients-a-pilot-study
#1
Łukasz J Krzych, Piotr Łój, Teresa Nowak, Wojciech Kazura, Piotr Knapik
Many studies have suggested a link between long-term PPI treatment and hypomagnesaemia, though none of them investigated the short-term exposure in high-risk patients. We sought to investigate this issue in 90 critically ill patients. We assessed serum Mg concentrations, necessity of Mg supplementation, PPI dose, duration of PPI therapy and route of administration. In multiple analysis we found that Mg supplementation (positive effect/p=0.03) and enteral route of PPI administration (negative effect/p=0.02) had significant impact on Mg concentration...
June 24, 2017: Acta Biochimica Polonica
https://www.readbyqxmd.com/read/28650846/dosimetric-verification-in-water-of-a-monte-carlo-treatment-planning-tool-for-proton-helium-carbon-and-oxygen-ion-beams-at-the-heidelberg-ion-beam-therapy-center
#2
Thomas Tessonnier, Till Tobias Boehlen, Francesco Cerutti, Alfredo Ferrari, Paola Roberta Sala, Stephan Brons, Thomas Haberer, Juergen Debus, Katia Parodi, Andrea Mairani
The introduction of "new" ion species in particle therapy needs to be supported by a thorough assessment of their dosimetric properties and by treatment planning comparisons with clinically used proton and carbon ion beams. In addition to the latter two ions, helium and oxygen ion beams are foreseen at the Heidelberg Ion beam Therapy (HIT) center as potential assets for improving clinical outcomes in the near future. We present in this study a dosimetric validation of a FLUKA-based Monte Carlo Treatment Planning tool (MCTP) for protons, helium, carbon and oxygen ions for spread-out Bragg peaks...
June 26, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28650664/the-dynamical-transition-of-lipid-multi-lamellar-bilayers-as-a-matter-of-cooperativity
#3
Judith Peters, Jérémie Marion, Francesca Natali, Efim Kats, Dominique J Bicout
The present study is the application of a two-state model formerly developed by Bicout, D.J. and and Zaccai, G., Biophys J 2001, 80 (3), 1115-23 1 to describe the dynamical transition exhibited in the atomic mean square displacements of biological samples in terms of dynamic and thermodynamic parameters. Data were obtained by elastic incoherent neutron scattering on 1,2-dimyristoyl-sn-glycero-3-phosphocholine lipid membranes in various hydration states and on one partially per-deuterated lipid membrane. Fitting the data with the model allowed investigating which parts of lipid molecules were mainly involved in the dynamical transition, heads, tails or both...
June 26, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/28650637/a-dft-tddft-study-on-the-sensing-mechanism-of-a-fluorescent-probe-for-hydrogen-sulfide-excited-state-intramolecular-proton-transfer-coupled-twisted-intramolecular-charge-transfer
#4
Yang Li, Tian-Shu Chu
By using density functional theory (DFT) and time-dependent density functional theory (TDDFT) methods, the sensing mechanism of a fluorescent probe 2-(2-hydroxyphenyl) benzothiazole (HBT) derivative HBTPP-S for hydrogen sulfide has been thoroughly studied. The thiolysis reaction has a moderate reaction barrier of 18.40 kcal mol-1, which indicates that the hydrogen sulfide sensing process has a favorable response speed. Due to the non-radiative donor-excited photoinduced electron transfer (d-PET, fluorophore as the electron donor) from the excited HBTPP group to the electron-withdrawing 2,4-dinitrophenyl group, as well as the inhibition of the proton transfer (PT) and the excited state intramolecular proton transfer (ESIPT) process by 2,4-dinitrophenyl group, the probe HBTPP-S is essentially non-fluorescent...
June 26, 2017: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/28650636/orthogonal-electric-field-measurements-near-the-green-fluorescent-protein-fluorophore-through-stark-effect-spectroscopy-and-pka-shifts-provide-a-unique-benchmark-for-electrostatics-models
#5
Joshua D Slocum, Jeremy T First, Lauren J Webb
Measurement of the magnitude, direction, and functional importance of electric fields in biomolecules has been a longstanding experimental challenge. pKa shifts of titratable residues have been the most widely implemented measurements of local electrostatic environment around the labile proton, and experimental data sets of pKa shifts in a variety of systems have been used to test and refine computational prediction capabilities of protein electrostatic fields. A more direct and increasingly popular technique to measure electric fields in proteins is Stark effect spectroscopy, where the change in absorption energy of a chromophore relative to a reference state is related to the change in electric field felt by the chromophore...
June 26, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/28650621/novel-cdta-based-bifunctional-chelators-for-stable-and-inert-mn-ii-complexation-synthesis-and-physicochemical-characterization
#6
Christian Vanasschen, Enikő Molnár, Gyula Tircsó, Ferenc K Kálmán, Éva Tóth, Marie Brandt, Heinz H Coenen, Bernd Neumaier
In the search for Mn(II) MR and PET/MR imaging agents with optimal balance between thermodynamic stability, kinetic inertness, and relaxivity, two novel bifunctional Mn(II) chelators (BFMnCs) based on CDTA (trans-1,2-diaminocyclohexane-N,N,N',N'-tetraacetic acid) were synthesized. A six-step synthesis, involving the buildup of a functionalized trans-1,2-diaminocyclohexane core, provided CuAAC-reactive 6a and 6b bearing an alkyne or azide substituent on the cyclohexane ring, respectively (CuAAC = Cu(I)-catalyzed azide-alkyne 1,3-dipolar cycloaddition)...
June 26, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28650617/kinetics-and-mechanism-of-the-autocatalytic-oxidation-of-bis-terpyridine-iron-ii-by-peroxomonosulfate-ion-oxone-in-acidic-medium
#7
Gábor Bellér, Gábor Lente, István Fábián
The autocatalytic oxidation of the bis(terpyridine)iron(II) complex, Fe(tpy)2(2+) by peroxomonosulfate ion (PMS) proceeds via the formation of the corresponding iron(III) complex (Fe(tpy)2(3+)) as the primary oxidation product. The proton-assisted dissociation of Fe(tpy)2(2+) and subsequent oxidation of Fe(2+) are side reactions in this system. In the initial stage of the reaction, a 1:1 adduct is formed between PMS and bis(terpyridine)iron(II), which decomposes in an intramolecular electron transfer reaction step...
June 26, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28650571/development-of-proton-responsive-catalysts
#8
REVIEW
Lin Wang, Ryoichi Kanega, Hajime Kawanami, Yuichiro Himeda
A changeable ligand, which involves in activation of a catalyst or assists a reaction, draws an increasing attention, in contrast to a classical ligand as spectator. Proton-responsive catalysts, which are capable of undergoing changes of properties on gaining/losing one or more protons, provides interesting features as follows: (i) catalyst activation by electronic effect, (ii) pH-tuning of water-solubility, and (iii) second-coordination-sphere interaction. On the basis of this catalyst design concept, we developed several highly efficient proton-responsive catalysts for CO2 hydrogenation as H2 storage, formic acid (FA) dehydrogenation as H2 production, and transfer hydrogenation...
June 26, 2017: Chemical Record: An Official Publication of the Chemical Society of Japan ... [et Al.]
https://www.readbyqxmd.com/read/28650510/experiment-and-theory-confirm-that-uv-laser-photodissociation-spectroscopy-can-distinguish-protomers-formed-via-electrospray
#9
Edward Matthews, Caroline E H Dessent
The identification of protonation sites in electrosprayed molecules remains a challenge in contemporary physical science. We present the first demonstration that low-resolution, UV laser photodissociation spectroscopy can be applied in situ to identify the protomers of para-aminobenzoic acid (PABA) formed via electrospray from a single solution. Electronic absorption spectra are recorded via photodepletion and photofragmentation for PABA electrosprayed from solutions of water and acetonitrile. Using this approach, two protomers can be straightforwardly identified, with only the carboxylic acid protomer being produced on electrospray from water while the amine-protonated isomer dominates upon electrospray from acetonitrile...
June 26, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28650492/exploiting-the-biosynthetic-machinery-of-streptomyces-pilosus-to-engineer-a-water-soluble-zirconium-iv-chelator
#10
Tomas Richardson-Sanchez, William Tieu, Michael P Gotsbacher, Thomas J Telfer, Rachel Codd
The water solubility of a natural product-inspired octadentate hydroxamic acid chelator designed to coordinate Zr(iv)-89 has been improved by using a combined microbiological-chemical approach to engineer four ether oxygen atoms into the main-chain region of a methylene-containing analogue. First, an analogue of the trimeric hydroxamic acid desferrioxamine B (DFOB) that contained three main-chain ether oxygen atoms (DFOB-O3) was generated from cultures of the native DFOB-producer Streptomyces pilosus supplemented with oxybis(ethanamine) (OBEA), which competed against the native 1,5-diaminopentane (DP) substrate during DFOB assembly...
June 26, 2017: Organic & Biomolecular Chemistry
https://www.readbyqxmd.com/read/28650138/photoelectrochemical-and-impedance-spectroscopic-analysis-of-amorphous-si-for-light-guided-electrodeposition-and-hydrogen-evolution-reaction
#11
Sung Yul Lim, Donghyeop Han, Yang-Rae Kim, Taek Dong Chung
For more efficient photoelectrochemical water splitting, there is a dilemma that a photoelectrode needs both light absorption and electrocatalytic faradaic reaction. One of the promising strategies is to deposit a pattern of electrocatalysts onto a semiconductor surface; leaving sufficient bare surface for light absorption, while minimizing concentration overpotential as well as resistive loss at the ultramicroelectrodes for faradaic reaction. This scheme can be successfully realized by "maskless" direct photoelectrochemical patterning of electrocatalyst onto an SiOx/amorphous Si (a-Si) surface by light-guided electrodeposition technique...
June 26, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28650042/monitoring-aggregation-of-a-ph-responsive-polymer-via-proton-exchange
#12
Ipsita Chakraborty, Ishita Mukherjee, Ujjal Haldar, Priyadarsi De, Rangeet Bhattacharyya
Understanding the changes in the macro-structure of amphiphilic pH-responsive polymers remains a relevant issue due to their potential use as drug delivery carriers. Since some of the amphiphilic polymers are known to exchange hydrogen ions with an aqueous solvent, we monitor the effective change of the surface to volume ratio of such polymer aggregates using solution-state nuclear magnetic resonance (NMR) spectroscopy. The surface to volume ratio with the help of UV-visible spectroscopy is shown to yield the average diameter of the polymer aggregates...
June 26, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28650016/prediction-of-1-h-nmr-chemical-shifts-for-clusters-of-imidazolium-based-ionic-liquids
#13
Su Chen, Ekaterina I Izgorodina
Nuclear magnetic resonance (NMR) has been widely used to elucidate the bulk structure of ionic liquids. In this work, we calculated (1)H NMR chemical shifts of 1-ethyl-3-methylimidazolium (C2mim(+)) ionic liquids combined with various anions such as chloride (Cl), tetrafluoroborate (BF4), hexafluorophosphate (PF6), acetate (OAc), trifluoroacetate (TFA), and dicyanamide (DCA). The previously established level of theory, HF/6-311G+(3df,2p), was used for the accurate prediction of NMR chemical shifts both in gas phase and in solvents with varying dielectric constant such as CHCl3 and ethanol...
June 26, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28649976/efficiency-of-analytical-and-sampling-based-uncertainty-propagation-in-intensity-modulated-proton-therapy
#14
N Wahl, P Hennig, H P Wieser, M Bangert
The sensitivity of intensity-modulated proton therapy (IMPT) treatment plans to uncertainties can be quantified and mitigated with robust/min-max and stochastic/probabilistic treatment analysis and optimization techniques. Those methods usually rely on sparse random, importance, or worst-case sampling. Inevitably, this imposes a trade-off between computational speed and accuracy of the uncertainty propagation. Here, we investigate analytical probabilistic modeling (APM) as an alternative for uncertainty propagation and minimization in IMPT that does not rely on scenario sampling...
June 26, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28649828/dimerization-of-the-conserved-n-terminal-domain-of-a-spider-silk-protein-controls-the-self-assembly-of-the-repetitive-core-domain
#15
Joschka Bauer, Thomas Scheibel
Spider silk proteins comprise a repetitive core domain with polyalanine and glycine/proline stretches flanked by highly conserved nonrepetitive N- and C-terminal domains. The termini are responsive to assembly triggers, sensing changes in the ionic (H+, phosphate) and mechanical (shear stress) environment along the spinning duct. Upon assembly, the N-terminal domain dimerizes in a pH-dependent manner induced by protonation of conserved acidic residues. So far, dimerization of N-terminal spider silk domains has been individually investigated in the absence of large core domains...
June 26, 2017: Biomacromolecules
https://www.readbyqxmd.com/read/28649773/synthesis-and-pka-determination-of-new-enantiopure-dimethyl-substituted-acridino-crown-ethers-containing-a-carboxyl-group-useful-candidates-for-enantiomeric-recognition-studies
#16
Tamás Németh, Gergő Dargó, József Levente Petró, Zsófia Petrik, Sándor Lévai, Balázs Krámos, Zoltán Béni, József Nagy, György Tibor Balogh, Péter Huszthy, Tünde Tóth
New enantiopure dimethyl-substituted acridino-18-crown-6 and acridino-21-crown-7 ethers containing a carboxyl group at position 9 of the acridine ring [(S,S)-8, (S,S)-9, (R,R)-10] were synthesized. The pKa values of the new crown ethers [(S,S)-8, (S,S)-9, (R,R)-10] and of an earlier reported macrocycle [(R,R)-2] were determined by UV-pH titrations. Crown ether (S,S)-8 was attached to silica gel by covalent bonds and the enantiomeric separation ability of the newly prepared chiral stationary phase [(S,S)-CSP-12] was studied by high-performance liquid chromatography (HPLC)...
June 26, 2017: Chirality
https://www.readbyqxmd.com/read/28649754/characterization-and-differentiation-of-geometric-isomers-of-3-methylfentanyl-analogs-by-gas-chromatography-mass-spectrometry-liquid-chromatography-mass-spectrometry-and-nuclear-magnetic-resonance-spectroscopy
#17
Tatsuyuki Kanamori, Yuko T Iwata, Hiroki Segawa, Tadashi Yamamuro, Kenji Kuwayama, Kenji Tsujikawa, Hiroyuki Inoue
The cis and trans isomers of 3-methylfentanyl and its three analogs were chemically synthesized, and these compounds were characterized and differentiated by gas chromatography/mass spectrometry (GC/MS), liquid chromatography/mass spectrometry (LC/MS), and nuclear magnetic resonance (NMR) spectroscopy. The cis and trans isomers of the 3-methylfentanyl analogs were completely separated by GC/MS. Although the high temperature of the GC injection port caused thermal degradation of β-hydroxy-3-methylfentanyl, the degradation was completely suppressed by trimethylsilyl derivatization...
June 26, 2017: Journal of Forensic Sciences
https://www.readbyqxmd.com/read/28649076/renal-clearance-and-urinary-excretion-of-omeprazole-in-healthy-female-volunteers-in-pakistan
#18
Nazia Qadir, Tanweer Khaliq, Rai Altaf Hussain, Ghulam Abbas Shah, Sadia Asharaf, Ahmad Raza, Nadia Noor
Omeprazole is a widely prescribed proton pump inhibitor to treat various gastric acid hyper secretion disorders. The present study was designed to evaluate the renal clearance and urinary excretion of omeprazole in eight healthy female volunteers to increase the understanding of the contributing factors such as demographics variability in the renal clearance and urinary excretion of omeprazole under indigenous conditions. The urine and blood samples were collected 0.5, 1, 1.5, 2, 3, 4, 6, 8 hours after oral administration of enteric coated omeprazole (20 mg) and drug concentration in the samples was determined by High Performance Liquid Chromatography (HPLC) with C18 column and UV detector...
March 2017: Pakistan Journal of Pharmaceutical Sciences
https://www.readbyqxmd.com/read/28648927/silibinin-capsules-improves-high-fat-diet-induced-nonalcoholic-fatty-liver-disease-in-hamsters-through-modifying-hepatic-de-novo-lipogenesis-and-fatty-acid-oxidation
#19
Chun-Xue Cui, Jing-Na Deng, Li Yan, Yu-Ying Liu, Jing-Yu Fan, Hong-Na Mu, Hao-Yu Sun, Ying-Hong Wang, Jing-Yan Han
ETHNOPHARMACOLOGICAL RELEVANCE: Silibinin Capsules (SC) is a silybin-phospholipid complex with silybin as the bioactive component. Silybin accounts for 50-70% of the seed extract of Silybum marianum (L.) Gaertn.. As a traditional medicine, silybin has been used for treatment of liver diseases and is known to provide a wide range of hepatoprotective effects. AIM OF THE STUDY: High fat diet (HFD)-induced nonalcoholic fatty liver disease (NAFLD) is a worldwide health problem...
June 22, 2017: Journal of Ethnopharmacology
https://www.readbyqxmd.com/read/28648804/the-single-igf-1-partial-deficiency-is-responsible-for-mitochondrial-dysfunction-and-is-restored-by-igf-1-replacement-therapy
#20
M Olleros Santos-Ruiz, M C Sádaba, I Martín-Estal, U Muñoz, C Sebal Neira, I Castilla-Cortázar
BACKGROUND & AIMS: We previously described in cirrhosis and aging, both conditions of IGF-1 deficiency, a clear hepatic mitochondrial dysfunction with increased oxidative damage. In both conditions, the hepatic mitochondrial function was improved with low doses of IGF-1. The aim of this work was to explore if the only mere IGF-1 partial deficiency, without any exogenous insult, is responsible for hepatic mitochondrial dysfunction. METHODS: Heterozygous (igf1(+/-)) mice were divided into two groups: untreated and treated mice with low doses of IGF-1...
June 2, 2017: Growth Hormone & IGF Research
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