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Johannes Lützenkirchen, Tim Scharnweber, Tuan Ho, Alberto Striolo, Marialore Sulpizi, Ahmed Abdelmonem
We present a measurement cell that allows simultaneous measurement of second harmonic generation (SHG) and streaming potential (SP) at mineral-water interfaces with flat specimen that are suitable for non-linear optical (NLO) studies. The set-up directly yields SHG data for the interface of interest and can also be used to obtain information concerning the influence of flow on NLO signals from that interface. The streaming potential is at present measured against a reference substrate (PTFE). The properties of this inert reference can be independently determined for the same conditions...
June 15, 2018: Journal of Colloid and Interface Science
Gideon Koren, Asher Ornoy, Matitiyahu Berkovich
Hyperemesis gravidarum (HG) is characterized by severe gestational nausea and vomiting, leading to dehydration, electrolyte imbalance and nutritional deficits. HG adversely affects the health and wellbeing of the woman. However, the detrimental impact of HG on fetal brain development has not been addressed. We evaluate herein the emerging evidence suggesting that HG interferes with human brain development, and discuss putative mechanisms. Evidence emerges from prospective developmental studies in offspring exposed in utero to HG, from studies of pregnancy outcome after in utero exposure to famine, as well as evidence on specific nutritional deficiencies affecting fetal brain development...
June 15, 2018: Reproductive Toxicology
Mariana F Lima, Iuri S Neville, Sergio Cavalheiro, Dafne C Bourguignon, Paolo Pelosi, Luiz M S Malbouisson
BACKGROUND: Balanced crystalloid solutions induce less hyperchloremia than normal saline, but their role as primary fluid replacement for children undergoing surgery is unestablished. We hypothesized that balanced crystalloids induce less chloride and metabolic derangements than 0.9% saline solutions in children undergoing brain tumor resection. METHODS: In total, 53 patients (age range, 6 mo to 12 y) were randomized to receive balanced crystalloid (balanced group) or 0...
June 15, 2018: Journal of Neurosurgical Anesthesiology
Byung Nam Kim, Alia Weaver, Marina Chumakov, Ileana M Pazos, Dianne L Poster, Karen Gaskell, Do Hung Han, Günther Scherer, Michael A Yandrasits, Byung Cheol Lee, Mohamad Al-Sheikhly
During the pulsed-electron beam direct grafting of neat styrene onto poly(tetrafluoroethylene-co-hexafluoropropylene) (FEP) substrate, the radiolytically-produced styryl and carbon-centered FEP radicals undergo various desired and undesired competing reactions. In this study, a high-dose rate is used to impede the undesired free radical homopolymerization of styrene and ensure uniform covalent grafting through 125-μm FEP films. This outweighs the enhancement of the undesired crosslinking reactions of carbon-centered FEP radicals and the dimerization of the styryl radicals...
June 18, 2018: Radiation Research
Kiminori Sato
In solid-like polymer electrolytes, salt precipitation (SP) followed by the occurrence of neutral ion pairs in polymer electrolytes is known to deteriorate ionic conductivity, but has not been the subject of intense study so far. Here, the mechanism of SP is studied for the polymer electrolyte consisting of poly(ethylene oxide) (PEO) and ionic liquid (IL) salt of 1-ethyl-3-methylimidazolium trifluoromethanesulfonate (EMImTf), which is one of the promising prototype systems due to its technological relevance...
June 18, 2018: Journal of Physical Chemistry. B
Nathalie R Wingert, Natália O Dos Santos, Sarah C Campanharo, André Jablonski, Martin Steppe
Microemulsion electrokinetic chromatography (MEEKC) is an electrophoretic methodology based on the separation of compounds by a microemulsionated electrolyte. There are few options for the evaluation of the stability and content of the oral anticoagulant rivaroxaban (RIV) in pharmaceutical formulations. RIV has low water solubility and undergoes ionization only under restricted pH conditions (pH < 1 or pH > 13), thus, hindering the application of free zone capillary electrophoresis as an analytical method...
April 18, 2018: Journal of Chromatographic Science
Laura K Schenk, Jiraporn Ousingsawat, Boris V Skryabin, Rainer Schreiber, Hermann Pavenstädt, Karl Kunzelmann
The Ca2+ -activated phospholipid scramblase and ion channel TMEM16F is expressed in podocytes of renal glomeruli. Podocytes are specialized cells that form interdigitating foot processes as an essential component of the glomerular filter. These cells, which participate in generation of the primary urine, are often affected during primary glomerular diseases, such as glomerulonephritis and secondary hypertensive or diabetic nephropathy, which always leads to proteinuria. Because the function of podocytes is known to be controlled by intracellular Ca2+ signaling, it is important to know about the role of Ca2+ -activated TMEM16F in these cells...
June 18, 2018: International Journal of Molecular Sciences
Sujaya Kumar Vishwanath, Hyunsuk Woo, Sanghun Jeon
Conductive-bridge random access memory (CBRAM) has become one of the most suitable candidates for non-volatile memory in next-generation information and communication technology. The resistive switching mechanism of CBRAM depends on the formation/annihilation of the conductive filament (CF) between the active metal electrode and the inert electrode. However, excessive ion injection from the active electrode into the solid electrolyte is reduces the uniformity and reliability of the resistive switching devices...
June 18, 2018: Nanotechnology
Alfredo Gonz Aacute Lez-Calder Oacute N, Martin Chavez-Paez, Enrique Gonzalez-Tovar, Marcelo Lozada-Cassou
Most theoretical and simulation studies on charged suspensions are at infinite dilution, and are focused on the electrolyte structure around one or two isolated particles. Some classic experimental studies with latex particles solutions exhibit interesting phenomenology which imply very long-range correlations. Here we apply an integral equation theory to a model charged macroions suspension, at finite volume fraction, and find an amplitude modulated charge inversions structure, with outsized amplitudes and of very long-range extension...
June 18, 2018: Journal of Physical Chemistry. B
Jongmyung Yoo, Jeonghwan Song, Hyunsang Hwang
In this study, we investigate the effect of cation amount in electrolyte on Ag/TiO2 based threshold&#13; switching devices based on field-induced nucleation theory. For this purpose, normal Ag/TiO2,&#13; annealed Ag/TiO2, and Ag-Te/TiO2 based TS devices are prepared, which have different cation&#13; amounts in their electrolytes during the switching process. First, we find that all of the prepared TS&#13; devices follow the field-induced nucleation theory with different nucleation barrier energy (W0) by&#13; investigating the delay time dependency at various voltages and temperatures...
June 18, 2018: Nanotechnology
Yue Zhang, Lu Gao, Emiel J M Hensen, Jan P Hofmann
The evaluation of the stability of emerging earth-abundant metal phosphide electrocatalysts by solely electrochemical current-potential sweeps is often not conclusive. In this study, we investigated Co2 P to evaluate its stability under both acidic (0.5 M H2 SO4 ) and alkaline (1.0 M KOH) hydrogen evolution (HER) conditions. We found that the electrochemical surface area (ECSA) of Co2 P only slightly increased in acidic conditions but almost doubled after electrolysis in alkaline electrolyte. The surface composition of the electrode remained almost unchanged in acid but was significantly altered in alkaline during current-potential sweeps...
June 8, 2018: ACS Energy Letters
Ming Ma, Kai Liu, Jie Shen, Recep Kas, Wilson A Smith
In this work, the highly selective and stable electrocatalytic reduction of CO2 to CO on nanostructured Ag electrocatalysts is presented. The Ag electrocatalysts are synthesized by the electroreduction of Ag2 CO3 formed by in situ anodic-etching of Ag foil in a KHCO3 electrolyte. After 3 min of this etching treatment, the Ag2 CO3 -derived nanostructured Ag electrocatalysts are capable of producing CO with up to 92% Faradaic efficiency at an overpotential as low as 290 mV, which surpasses all of the reported Ag catalysts at identical conditions to date...
June 8, 2018: ACS Energy Letters
Satyendra Kumar Sonkar, Satish Kumar, Neeraj Kumar Singh
Hypokalemia is a serious and life-threatening clinical condition. We present a case of a 45-year-old male, with known hyperthyroidism presenting with profound tremor, irritability, quadriparesis, and labored breathing since morning, on the day of admission. Arterial blood gas analysis showed severe hypokalemia. Patient's vital was stabilized and patient's oxygen saturation was maintained on oxygen inhalation. Intravenous potassium chloride infusion was administered with regular monitoring of vitals and electrolytes...
May 2018: Indian Journal of Critical Care Medicine
Radu-Cristian Moldovan, Ede Bodoki, Anne-Catherine Servais, Bezhan Chankvetadze, Jacques Crommen, Radu Oprean, Marianne Fillet
A targeted CE-MS approach was developed for the chiral analysis of biologically relevant amino acids in artificial cerebrospinal fluid (aCSF). In order to achieve chiral resolution, the five amino acids (Ser, Asn, Asp, Gln and Glu) were derivatized with (+)-1-(9-fluorenyl)ethyl chloroformate ((+)-FLEC). The diastereoselectivity was found to be highly dependent on pH for all analytes and the optimized background electrolyte (BGE) consisted of 150 mM acetic acid, adjusted to pH 3.7 with NH4 OH. Furthermore, a reversal of the migration order of Asp derivatives was observed...
June 13, 2018: Journal of Chromatography. A
Xiaoyang Cui, Cheng Tang, Xiaomeng Liu, Chen Wang, Wenjun Ma, Qiang Zhang
Catalytic conversion of dinitrogen (N2) into ammonia under ambient conditions represents one of the Holy Grails in sustainable chemistry. However, owning to the kinetically complex and energetically challenging N2 reduction reaction (NRR) process, NRR electrocatalysts with high catalytic activity and high selectivity are rare. In this contribution, as a proof-of-concept, we demonstrate that both the NH3 yield and NH3 faradaic efficiency (FE) at ambient conditons can be improved by modification of the hematite nanostructure surface...
June 15, 2018: Chemistry: a European Journal
Filip Moučka, Jiří Kolafa, Martin Lísal, William R Smith
We present a molecular-level simulation study of CaCl2 in water and crystalline hydrates formed by CaCl2 at ambient (298.15 K, 1 bar) conditions and at a high-temperature high-pressure state (365 K, 275 bars) typical of hydraulic fracturing conditions in natural-gas extraction, at which experimental properties are poorly characterized. We focus on simulations of chemical potentials in both solution and crystalline phases and on the salt solubility, the first time to our knowledge that such properties have been investigated by molecular simulation for divalent aqueous electrolytes...
June 14, 2018: Journal of Chemical Physics
Yixing Chen, Nathan Dupertuis, Halil I Okur, Sylvie Roke
The temperature dependence of the femtosecond elastic second harmonic scattering (fs-ESHS) response of bulk light and heavy water and their electrolyte solutions is presented. We observe clear temperature dependent changes in the hydrogen (H)-bond network of water that show a decrease in the orientational order of water with increasing temperature. Although D2 O has a more structured H-bond network (giving rise to more fs-ESHS intensity), the relative temperature dependence is larger in H2 O. The changes are interpreted in terms of the symmetry of H-bonds and are indicators of nuclear quantum effects...
June 14, 2018: Journal of Chemical Physics
Yizhak Marcus
The effect of ions on the structure of water in dilute solutions, whether they are structure-makers or structure-breakers, is manifested also in the volatility of the water. For more than 40 uni-univalent electrolytes, there is a linearly increasing relationship between 2φ(m = 0.4) - φ(m = 0.2), where φ is the osmotic coefficient and m is the molality, and the difference between the viscosity B-coefficients of the cation and anion. Exceptions to this relationship are electrolytes with highly structure-making anions and with hydrophobic cations...
June 14, 2018: Journal of Chemical Physics
Virginia Mazzini, Guangming Liu, Vincent S J Craig
We present an experimental investigation of specific-ion effects in non-aqueous solvents, with the aim of elucidating the role of the solvent in perturbing the fundamental ion-specific trend. The focus is on the anions: CH3 COO- >F- >Cl- >Br- >I- >ClO4 - >SCN- in the solvents water, methanol, formamide, dimethyl sulfoxide (DMSO), and propylene carbonate (PC). Two types of experiments are presented. The first experiment employs the technique of size exclusion chromatography to evaluate the elution times of electrolytes in the different solvents...
June 14, 2018: Journal of Chemical Physics
A Muralidharan, L R Pratt, M I Chaudhari, S B Rempe
Laying a basis for molecularly specific theory for the mobilities of ions in solutions of practical interest, we report a broad survey of velocity autocorrelation functions (VACFs) of Li+ and PF6 - ions in water, ethylene carbonate, propylene carbonate, and acetonitrile solutions. We extract the memory function, γ(t), which characterizes the random forces governing the mobilities of ions. We provide comparisons controlling for the effects of electrolyte concentration and ion-pairing, van der Waals attractive interactions, and solvent molecular characteristics...
June 14, 2018: Journal of Chemical Physics
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