Concentration Of NaI Research Articles

Fucoidan/κ-carrageenan mixed gel: Effect of anions of different valence including chloride, bromide, iodide, sulfate and phosphate

The effects of the differently charged anions, NaCl, NaBr, NaI, Na2SO4, and Na3PO4 on the gel properties and structure of the fucoidan/κ-carrageenan mixed gel (FC) were investigated using the rheometer, texture analyzer, LF-NMR, Cryo-SEM, FT-IR, and XRD. At a certain concentration, Cl− and Br− could stabilize the helical conformation of the gel through electrostatic shielding. The addition of SO42− and PO43− would reduce the strength of the gel. And I− would soften the gel. With increasing anion concentration, the electrostatic repulsion between FUC and KC was gradually enhanced. The FUC dispersions remained liquid after the addition of anions, while FC gelled depending on the type and concentration of anions. The elastic modulus increased with increasing concentration of NaCl and NaBr, but decreased with increasing concentration of NaI, Na2SO4, and Na3PO4. Moreover, the addition of anions promoted the water migration of FC, as reflected by the T23 relaxation time changing from high to low and the significantly higher migration of NaCl and NaBr than NaI and Na2SO4. The pores of the gel microstructure change from disordered to uniform. The FT-IR and XRD results were well related to the structural changes. There is electrostatic repulsion between anion and FC, and the binding ability of FC to monovalent anions and trivalent anions is better than that of divalent anions. Overall, this study could provide a theoretical basis for the design and development of FUC-based gels.

Substantial ion conduction in the biopolymer membrane: Efficacy of NaI on sodium alginate matrix

Water-soluble sodium alginate-based biopolymer electrolyte membranes integrated with NaI have been prepared by solution cast route and analyzed in terms of its complexation, degree of crystallinity, glass transition temperature and ionic conductivity. With the increasing concentration of NaI in the biopolymer matrix, the amorphous phase becomes prominent besides NaI content changes the transition temperature values and the ionic conductivity. The membrane can fetch high ionic conductivity in the order of 10−2 S cm−1. The present study lays the groundwork for scrutinizing the optimal concentration for obtaining high ion conductive membranes which are favorable for all solid batteries.

Exploration of Gas-Liquid Interfaces for Liquid Water and Methanol Using Extreme Ultraviolet Laser Photoemission Spectroscopy.

We present a study using extreme UV (EUV) photoemission spectroscopy of the valence electronic structures of aqueous and methanol solutions using a 10 kHz EUV light source based on high-order harmonic generation and a magnetic bottle time-of-flight electron spectrometer. Two aspects of the observed spectra are highlighted in this study. One is variation of the vertical ionization energy (VIE) for liquids as a function of the solute concentration, which is closely related to surface dipoles at the gas-liquid interface. The experimental results show that the VIE of liquid water increases slightly with increasing concentrations of NaCl and NaI and decreases with NaOH. The VIE of liquid methanol was also found to change slightly with NaI. On the other hand, tetrabutylammonium iodide (TBAI) and butylamine (BA) clearly reduce the VIE for liquid water, which is attributed to the formation of an electric double layer (EDL) by segregated solutes at the gas-liquid interface. As evidence for this, when the pH of an aqueous BA solution is reduced to protonate BA, the VIE shift gradually decreases because the protonated BA moves into the bulk to suppress the influence of the EDL. We computed the surface potentials for these solutions using molecular dynamics simulations, and the results supported our interpretation of the experimental results. Another observation is the variation of the relative energy and shape of individual photoelectron bands for solvents, which is related to alteration of the structure and constituents of the first solvation shell of ionized solvent molecules. All of the solutes cause changes in the photoelectron spectra at high concentration, one of the most prominent of which is the degree of splitting of the 3a1 band for liquid water and the 7a' band for liquid methanol, which are sensitive to hydrogen bonding in the liquids. The 3a1 splitting decreases with the increasing concentration of NaI, NaCl, and NaOH, indicating that Na+ penetrates into the hydrogen-bonding network to coordinate to a nonbonding electron of a water molecule. On the other hand, TBAI and BA cause smaller changes in the 3a1 splitting. Full interpretation of these spectroscopic features awaits extensive quantum chemical calculations and is beyond the scope of this study. However, these results illustrate the strong potential of EUV laser photoemission spectroscopy of liquids for exploration of interfacial and solution chemistry.

Analysis of Eco-Tourism Climate Resources in Xingwen, China Based on the Comfort Index and the Negative Air (Oxygen) Ion

The present work investigates an analysis of Eco-Tourism Climate Resources in Xingwen, China based on the Comfort Index and Negative Air (Oxygen) Ion (“NAI” for short in this article) concentration. The daily temperature, precipitation, wind speed, sunshine hours, and relative humidity data of the Xingwen National Meteorological Station from 1999 to 2018, as well as the NAI data of Feiwu Cave station and Shoushan Lake station in Xingwen of 2018 were used in this study. Based on the analysis of the characteristics of basic meteorological elements, the index of climate comfort of human living environment and the NAI variation in Xingwen, the eco-tourism climate resources in this area were evaluated comprehensively. The results show that: The climate is mild, the precipitation is abundant and the seasonal variation trend of precipitation and heat is similar in the study area. The annual average temperature of this area is 17.8°C, the annual average precipitation is 1096 mm, the annual average precipitation days are 186 days, the annual average relative humidity is 81%, the annual average wind speed is 1.3 m/s, and the annual average sunshine hours are 999 h. The living environment comfort level reaches the “comfort” level for 6 months per year. In addition, the concentration of NAI in Xingwen remains at the highest level 7 throughout the year, and the rate of good air quality is extremely high. Overall, the study area has high-quality ecological climate resources that are conducive to the development of forest recuperation, leisure and vacation and other ecological tourism activities.

Sensitization of SnO2 Single Crystals with Multidentate‐Ligand‐Capped PbS Colloid Quantum Dots to Enhance the Photocurrent Stability

AbstractA PbS quantum dot (QD) sensitized SnO2 solar cell has the advantage of producing photocurrent from near‐infrared to the ultraviolet that covers much of the higher energy solar spectrum. However, the long‐chain ligands, that are frequently used to cap as‐synthesized QDs, inhibit the charge transfer ability to the sensitized substrate, decreasing the photovoltaic efficiency in the device. Herein, we present a fast and efficient ligand‐exchange strategy for the replacement of synthetically convenient hydrophobic oleic acid (OA) ligands with short‐chain multidentate hydrophilic ligands such as meso‐2,3‐dimercaptosuccinic acid (DMSA) that increase the electronic coupling to the SnO2 substrate. Results from ultraviolet‐visible‐near‐infrared (UV‐Vis‐NIR) spectroscopy, X‐ray diffraction (XRD) measurements, and high‐resolution transmission electron microscopy (HR‐TEM) micrographs verify that this ligand‐exchange method produces no significant QD size or crystal‐structure changes. X‐ray photon spectra (XPS) results suggest that thiol groups from DMSA are likely bound to the PbS QDs compared to other bifunctional ligands. The PbS QDs sensitized SnO2 single crystals were characterized with atomic force microscopy (AFM), and with incident photon current efficiency (IPCE) spectra. Furthermore, it was shown that the IPCE of DMSA‐capped PbS QDs sensitized SnO2 single crystals retains >80% of its initial value after >7 hours of illumination within an electrolyte containing a high concentration of NaI whereas other ligand capped PbS QDs degraded much more rapidly.

Single-Crystal Electrochemistry Explains Why Cu Nanoplates Form in the Presence of I-

Shape-directing agents such as halide ions and organic adsorbates play an important role on the growth of metallic nanocrystals. Halide ions, in particular, have been of interest due to their importance in determining the shape of metallic nanocrystals. A systematic study showed that halide ions determine the final shape of Au nanocrystals such as cubes, plates, and various polyhedrons.1 Additionally, it has been demonstrated that the diameter of Ag nanowires can be tuned by modulating the concentration of Br- in a polyol synthesis.2 Finally, it was reported that varying concentrations of I- impurities found in different brands of CTAB affect the formation of gold nanorods.3 However, although we know that halide ions can dictate the shape of nanocrystals, there is no direct evidence clarifying the role of halide ions and their interaction with other organic shape-directing agents on metal surfaces. In a recently published article, Kim et al demonstrated the power of single-crystal electrochemistry in elucidating the previously-misunderstood mechanism of Cu nanowire growth.4 Until recently, it was believed that capping agents selectively bind onto {100} facets—which make up the sides of penta-twinned Cu nanowires—and inhibit atomic addition, thereby directing anisotropic growth on the {111} facets that make up the ends of the nanowires.5,6 However, there were limited experimental results that supported this hypothesis. By using Cu(111) and Cu(100) single-crystal electrodes to simulate the crystal facets of Cu nanowires, Kim et al demonstrated that HDA (a shape-directing agent) passivated both the Cu(111) and Cu(100) surfaces equally, unlike previously hypothesized.4 In fact, they found that it was Cl- that selectively facilitated atomic addition on Cu(111) by interrupting the passivating HDA self-assembled monolayer (SAM), leading to anisotropic growth. Using a similar method, this presentation aims to demonstrate how and why Cu nanoplates grow when I- is introduced to a Cu nanowire growth solution using single-crystal electrochemistry. Synthetic results have shown that when a minimum concentration of NaI (75 µM) is introduced to an HDA-Cl--based synthesis for Cu nanowires, Cu nanoplates can be obtained (Fig. 1). Preliminary electrochemical measurements with a polycrystalline Cu electrode showed that I- was more effective in disrupting the HDA SAM compared to Cl-. In this presentation, we will introduce the interactions between I-, Cl-, and HDA on Cu single-crystal electrodes to understand why the addition of I- ions causes a change in nanocrystal structure from nanowires to nanoplates.

The liquid ammoniate of sodium iodide as an alternative electrolyte for sodium ion batteries: The case of titanium dioxide nanotube electrodes

Efforts for the development of sodium ion batteries (NIB) are focusing on insertion electrode materials rather than on novel electrolytes. In a radically new approach, sodium insertion into amorphous TiO2 nanotubes, chosen as a typical electrode material for NIBs, is studied for the NaI liquid ammoniate (NaI·3.3NH3) and compared with the behavior in typical organic electrolytes (for instance 1 M NaClO4 in propylene carbonate, PC). The liquid ammoniate leads to significantly larger electrode capacities (between 0.5 and 2.6 V vs. Na+/Na): 145 mA h g−1 in NaI·3.3NH3 versus 105 mA h g−1 in 1M NaClO4/PC at 1 mA cm−2 (14C for the ammoniate). This is linked to the outstanding conductivity and sodium concentration of NaI·3.3NH3, together with the much smaller charge transfer resistance observed for this electrolyte. In more general vein, the prospects for using the NaI·3.3NH3 liquid ammoniate in NIBs are finally discussed.

Dielectrical and electrical properties of PVA-NaI composites

The electrical characteristics of polyvinyl alcohol PVA doped with different concentrations (0, 1, 2, 3 and 4wt%) of sodium iodide NaI powder were studied. The films are prepared using solution casting technique, in order to investigate the effect of sodium iodide NaI additions on the electrical properties of PVA host. The D.C conductivity measured by measuring the D.C electrical resistance using the Keithly Electrometer type 616C, and for different temperatures ranging from 30 – 70oC.
 The dielectric properties measured by measuring the capacitor and the loss angle tangent as a function of the alternating electric field frequency using the Agilent impedance analyzer 4294A, within the frequency range 50 – 6 ×106 Hz at room temperature. The experimental results showed that the dielectric constant is decrease with increase frequency of applied electrical field and increase with increasing concentrations, dielectric loss is increase with increasing frequency of applied electrical field to be 1MHz after this it was decreasing, A.C electrical conductivity are increasing with increasing frequency of applied electrical field, also, the results showed that the D.C electrical conductivity are increasing with increase concentration of NaI and temperature, activation energy are decreasing with increase concentration of additive salt.

Determination of trace methanesulfonates in drug matrix using derivatization and headspace single drop microextraction followed by high-performance liquid chromatography with ultraviolet detection

The selective and sensitive determination of potential genotoxic methanesulfonate impurities in drug substances is highly challenging. A new method is reported for testing of methyl methanesulfonate (MMS), ethyl methanesulfonate (EMS) and isopropyl methanesulfonate (IPMS) in active pharmaceutical ingredients (APIs). Headspace single drop microextraction (HS-SDME) with room-temperature ionic liquid (RTIL) as extractant was employed to preconcentrate analytes and eliminate the drug matrix simultaneously. In order to increase volatilities for HS extraction and to improve their reactivity of the further derivatization at the same time, sodium iodide (NaI) was added to the sample to derivatize methanesulfonates to the corresponding iodoalkanes. The iodoalkanes in the extract were derivatized with N, N-diethyldithiocarbamate (DDTC) after HS-SDME, followed by separation and detection with high-performance liquid chromatography with ultraviolet detection (HPLC-UV). Several important parameters, including reaction temperature, reaction time and concentration of NaI, sample volume, microdrop volume, stirring rate, salt addition, extraction time, concentration, reaction time and reaction temperature of DDTC were investigated. Under the optimal conditions, LODs and LOQs of all methanesulfonates were 15 ng mL−1 and 40 ng mL−1, respectively. Linearity (correlation coefficient values r > 0.999) and precision (the relative standard deviations were 1.0–4.6%) of six repeated injections were obtained. The recoveries at three spiked concentration levels were all in the range of 86.2–107.5% with the relative standard deviations <3.5%. The method reported here avoids interference of drug substances efficiently and detects methanesulfonate impurities in high sensitivity by HPLC-UV in Imatinib Mesylate and Levofloxacin Mesylate.

Review on Research of the Negative Air Ion Concentration Distribution and its Correlation with Meteorological Elements in Mountain Tourist Area

This paper focuses on the research progress of the negative air ion concentration distribution characteristics and its correlation with meteorological elements in mountain tourist areas for recent decades in China. Many researches showed that the distribution of negative air ion in mountain tourist areas has obvious daily and seasonal variations, and its space changes also have regularity. In a day, the NAI concentration will appear alternately with peaks and troughs. The changes of NAI concentration are the summer, autumn high, winter and spring low, the highest in summer, the lowest in winter. In the middle and low altitude areas, NAI concentration is positively correlated with elevation, and negative correlation in high altitude. The concentration of NAI is related to wind speed, air humidity, air temperature, solar radiation, weather conditions, and other meteorological elements. Most research results show that humidity is the most important meteorological factor affecting NAI concentration. The NAI concentration in mountainous scenic spots is significantly positively correlated with relative humidity and rainfall intensity, positively correlated with wind speed and solar radiation, negatively correlated with air temperature. However, due to different sources of monitoring data, observations difference in time, different sample size and other elements, the conclusions on negative air ion concentration distribution characteristics and its correlation with the meteorological factors are not entirely consistent. Negative air ion monitoring equipment should be gradually standardize to ensure the reliability of monitoring data in the future, while we should take advantage of years of continuous observations to carry the study of correlation between negative air ion and meteorological factors, and this will provide a theoretical basis for negative air ion concentration forecasts.

Three-dimensional viscous fingering of miscible fluids in porous media

Viscous fingering is a flow instability that is induced at the displacement front when a less-viscous fluid (LVF) displaces a more-viscous fluid (MVF). Because of the opaque nature of porous media, most experimental investigations of the structure of viscous fingering and its development in time have been limited to two-dimensional porous media or Hele–Shaw cells. In this study, we investigate the three-dimensional characteristics of viscous fingering in porous media using a microfocused x-ray computer tomography (CT) scanner. Similar to two-dimensional experiments, characteristic events such as tip-splitting, shielding, and coalescence were observed in three-dimensional viscous fingering as well. With an increase in the Péclet number at a fixed viscosity ratio, M, the fingers appearing on the interface tend to be fine; however, the locations of the tips of the fingers remain the same for the same injected volume of the LVF. The finger extensions increase in proportion to ln M, and the number of fingers emerging at the initial interface increases with M. This fact agrees qualitatively with linear stability analyses. Within the fingers, the local concentration of NaI, which is needed for the x-ray CT scanner, linearly decreases, whereas it sharply decreases at the tips of the fingers. A locally high Péclet number as well as unsteady motions in lateral directions may enhance the dispersion at the tips of the fingers. As the viscosity ratio increases, the efficiency of each sweep monotonically decreases and reaches an asymptotic state; in addition, the degree of mixing increases with the viscosity ratio. For high flow rates, the asymptotic value of the sweep efficiency is low for high viscosity ratios, while there is no clear dependence of the asymptotic value on the Péclet number.4 MoreReceived 21 July 2017DOI:https://doi.org/10.1103/PhysRevFluids.2.103902©2017 American Physical SocietyPhysics Subject Headings (PhySH)Research AreasFlows in porous mediaMixing in geophysical flowsSaffman-Taylor instabilityFluid Dynamics

Aqueous controllable synthesis of spindle-like palladium nanoparticles and their application for catalytic reduction of 4-nitrophenol

In this study, an effective wet-chemical route was developed in an aqueous solution for the synthesis of spindle-like palladium nanoparticles (Pd NPs). Spindle-like Pd NPs in high-yield were successfully synthesized by using cetyltrimethylammonium chloride (CTAC) as surfactant and ascorbic acid (AA) as reduction reagent. The influence factors including the concentration of CTAC, AA, and NaI, as well as the reaction temperature for synthesis of spindle-like Pd NPs were systematically investigated. The formation mechanism of spindle-like Pd NPs was proposed on the basis of these experimental results. Spindle-like Pd NPs with high density of twins and sharp edges exhibit enhanced catalytic activities for the reduction of 4-nitrophenol.

On the rheology of refractive-index-matched, non-Newtonian blood-analog fluids for PIV experiments

Four commonly used refractive-index (RI)-matched Newtonian blood-analog fluids are reviewed, and different non-Newtonian blood-analogs, with RI of 1.372–1.495, are investigated. Sodium iodide (NaI), sodium thiocyanate (NaSCN) and potassium thiocyanate are used to adjust the RI of blood-analogs to that of test sections for minimizing optical distortions in particle image velocimetry data, and xanthan gum (XG) is added to the fluids to give them non-Newtonian properties (shear thinning and viscoelasticity). Our results support the general belief that adding NaI to Newtonian fluids matches the RI without changing the kinematic viscosity. However, in contrast to claims made in a few studies that did not measure rheology, our investigation revealed that adding NaI or NaSCN to XG-based non-Newtonian fluids changes the viscosity of the fluids considerably and reduces the shear-thinning property. Therefore, the RI of non-Newtonian blood-analog fluids with XG cannot be adjusted easily by varying the concentration of NaI or NaSCN and needs more careful rheological study.

Synthesis and optimization of P(MMA-BA-MAA)/PEG-based polymer gel electrolytes

A polymer gel electrolyte based on poly(methyl methacrylate-butyl acrylate-methacrylic acid)/polyethylene glycol 400 blend (P(MMA-BA-MAA)/PEG400) was successfully prepared by a simple and efficient procedure. The optimal ionic conductivity was achieved to be 3.12 mS cm−1 at the temperature of 30 °C when the electrolyte has the composition of 20 wt% P(MMA-BA-MAA)/PEG400 blend, 0.6 M NaI, and 0.06 M I2 in the solvent γ-butyrolactone (GBL). For tuning the ionic conductivity, various additives were introduced into the polymer gel electrolytes. The measured values of open circuit voltage, short circuit current, and total photovoltaic efficiency indicates that the adding of pyridine (PY) leads to better performance of the final dye-sensitized solar cells (DSSCs), while the adding of Guanidine thiocyante (GuSCN) leads to a worse one. 4-Tert-butylpyridine (TBP) additive takes a more complex effect on the performance of the final DSSCs. For polymer gel electrolyte with 0.5 M pyridine, the final fabricated dye-sensitized solar cell has overall energy conversion efficiency (η) of 3.63 % (0.16 cm2 active area) under AM 1.5 at irradiation of 100 mW cm−2, which reached the level of the liquid electrolyte based device (η = 3.83 % at 0.16 cm2 active area). Meanwhile, this gel electrolyte exhibits well long-term stability. The mechanism analysis revealed the dependences of ionic conductivity on the concentration of polymer and NaI and the temperatures.

Dynamics of Formamide Ionic Solutions Investigated by Ultrafast Optical Kerr Effect

Molecular dynamics of formamide solutions of alkali metal halide salts were investigated using the time-resolved ultrafast optical Kerr effect (OKE) to observe the effects of ion solvation on the dynamics of a nonaqueous high-permittivity H-bonding solvent. The picosecond orientational and ultrafast intermolecular dynamics of liquid formamide as a function of concentration of NaI and KI are compared with the temperature effect on the pure solvent. The effect of a range of other salts at fixed concentration is also recorded. Transient OKE and corresponding low-frequency (THz) Raman spectra of the solutions revealed differences in the solvent dynamics caused by ion solvation. Increasing concentrations of NaI and KI have the effect of slowing down the diffusive reorientation and reducing the librational frequencies of formamide, with cation-related effects observed on the THz Raman spectrum. These effects are discussed in terms of an ion perturbation of the H-bonding structure in the solution. This approach provides a valuable means of investigating the dynamics, structure, and interactions in complex, interacting systems.

Some Experiments on Sorption Behavior of Iodide ions into CSH Gel under the Condition Saturated with Saline Groundwater

ABSTRACTThe main hydrate of cement is calcium silicate hydrate (CSH). Such a cement-based material is essential for constructing the geological disposal system of TRU radioactive wastes including I-129 in Japan. So far, the sorption behavior of iodine on CSH gel has been examined by using the CSH samples dried once. However, the Japan’s repository would be constructed under water table. Therefore, we must focus on also the interaction of altered cementitious material and iodine under the condition saturated with saline groundwater.In this study, the sorption behavior of iodide ions into CSH gel, formed without dried processes, was examined in imitated saline groundwater. Ca/Si ratio was set to 0.4, 0.8, 1.2 and 1.6, and NaCl concentration of each sample also was set to 0.6 M, 0.06 M or 0.006 M. These samples were synthesized with CaO, SiO2 (fumed silica), and distilled water in a given combination of 20 ml/g in liquid/solid ratio. A NaI solution was added after curing the CSH gel (hereinafter referred to as the “Surface sorption sample”) for 7 days, setting the initial concentration of NaI to 0.5 mM in sample tube. The values of Eh and pH of each sample showed iodide ions as the chemical species of iodine in the sample tube. Furthermore, this study prepared the “Co-precipitation sample” of CSH gel with iodide ions. Here, the NaI solution was added before curing the CSH gel. For all samples, the contact time-period of the CSH gel with iodide ions was set to 7 days. After each contact time-period, each sample for analyses was separated into the solid and the liquid phases by 0.20 µm membrane filter. In the liquid phase, the concentrations of Ca, I, Si and Na ions in the liquid phase were measured by ICP-AES. Besides, the Raman spectra were obtained from the solid phases of the surface sorption sample and the co-precipitation sample without dried process.The results showed that the sorption of iodide ions into CSH gel strongly depends on the amount of water included in the CSH gel. Such a sorption behavior was confirmed in both co-precipitation samples and the surface sorption samples, even if the Ca/Si ratio is low. This means that iodide ions can be easily immobilized through the water-molecular of CSH gel. Besides, Na concentration did not so much affect the sorption behavior of iodide ions into CSH gel. In addition, the Raman spectra showed that the degree of polymerization of SiO4 tetrahedrons in CSH gel was unaffected with increasing Na ions concentration. These results suggest that the CSH gel saturated with groundwater would retard the migration of iodide ions, even if the groundwater includes salinity.

Surveillance for Oseltamivir-resistant influenza pandemic A H1N1 viruses in Guangdong province

Objective To investigate the susceptibility to oseltamivir of influenza pandemic A (H1N1) 2009 viruses in Guangdong province during 2009,provide valuable information of prescription for clinics,and elucidate the variant trend of the epidemic strain based on phylogenetic analysis.Methods During April to December 2009,clinical specimens were collected from sentinel hospitals covering the whole Guangdong province.Virus isolation was performed by in MDCK cells or embryonated chicken eggs.A fluorescence-based neuraminidase (NA) enzyme inhibition assay was conducted to measure influenza susceptibility.The NAI susceptibility of influenza virus was expressed as the concentration of NAI needed to inhibit the NA enzyme activity by 50％.A subset of 68 viruses were performed NA sequencing for detecting resistant mutations and studying variant trends.Results During surveillance,221 influenza pandemic A ( H1N1 ) viruses were isolated.All strains were sensitive to oseltamivir inhibition assay,with a median IC50 of 0.24 nmol/L (range 0.02 -1.66 nmol/L).No mutation related to resistance was found.Phylogenic analysis illustrated that these NA genes were homology high to 99.5％ - 100.0％ with those from other countries.Conclusions influenza pandemic A (H1N1) 2009 viruses were sensitive to oseltamivir in Guangdong,and useful for prophylaxis and treatment of influenza infection.Little selective pressure was found by phylogenic analysis.Our laboratory will continue to observe antiviral-resistance among circulating influenza viruses. Key words: Influenza A virus, H1N1 subtype; Oseltamivir; Drug resistance,viral

Solvation Structure of I− and Na+ on the Surface of NaI Aqueous Solution Studied by Photodetachment Spectroscopy in Combination with Mass Spectrometry

We investigated solvation structures of I(-) and Na(+) on an aqueous solution surface by photodetachment spectroscopy and mass spectrometry. An aqueous solution of NaI was introduced into the vacuum as a continuous liquid flow (liquid beam), and the liquid beam was irradiated with a UV laser pulse. The abundance of electrons emitted by the laser excitation was measured as a function of wavelength (photodetachment spectroscopy). For a concentrated aqueous solution of NaI, we observe an absorption peak at longer wavelengths than the charge-transfer-to-solvent band of I(-) in solution. This feature is assigned to the photoabsorption of I(-) at the surface. This finding indicates that when the concentration of NaI is high (>1.0 M), I(-) exists on the solution surface. The identity of the ion clusters ejected from the liquid beam following selective laser excitation of I(-) on the surface or I(-) inside the solution was revealed by mass spectrometry. The mass spectra show that Na rich clusters are formed when I(-) inside the solution is excited, whereas Na rich clusters are hardly formed by the excitation of surface I(-). These findings lead us to conclude that Na(+) does not exist on the surface of the NaI aqueous solution.

Overall Water Splitting under Visible Light through a Two‐Step Photoexcitation between TaON and WO3 in the Presence of an Iodate–Iodide Shuttle Redox Mediator

A two-step, photocatalytic water splitting system consisting of Pt-loaded TaON (a H(2) evolution photocatalyst), Pt-loaded WO(3) (an O(2) evolution photocatalyst), and an iodate-iodide (IO(3)(-)/I(-)) shuttle redox mediator is investigated under visible light irradiation. Photocatalytic oxidation of water to O(2) and reduction of IO(3)(-) to I(-) proceeded with good selectivity over the Pt-WO(3) photocatalyst, even in the presence of a considerable amount of I(-) anions in the solution. The key difference between the adsorption properties of IO(3)(-) and I(-) anions on WO(3) strongly suggested that the photoexcited electrons could react efficiently with IO(3)(-) adsorbed on WO(3), whereas the photogenerated holes selectively reacted with water molecules owing to the low adsorptivity of I(-) on WO(3). Photocatalytic H(2) evolution on Pt-TaON proceeded efficiently, accompanied by I(-) oxidation to IO(3)(-) due to a substantial amount of adsorption of I(-) anions on the surface, whereas H(2) evolution was significantly inhibited by the competitive adsorption of IO(3)(-), which consumes photoexcited electrons. It was also found that WO(3) photocatalysts loaded with platinum oxide (PtO) showed a much higher activity for O(2) evolution in the presence of the electron acceptor IO(3)(-), compared to those loaded with Pt metal. Overall water splitting at a steady rate was demonstrated using a combination of Pt-TaON and Pt(PtO)-WO(3) in an aqueous NaI solution with neutral or weakly acidic pH values, where the concentration of NaI significantly affected the efficiency.

Co-Ion and Ion Competition Effects: Ion Distributions Close to a Hydrophobic Solid Surface in Mixed Electrolyte Solutions

We consider within a modified Poisson-Boltzmann theory an electrolyte, with different mixtures of NaCl and NaI, near uncharged and charged solid hydrophobic surfaces. The parametrized potentials of mean force acting on Na+, Cl-, and I- near an uncharged self-assembled monolayer were deduced from molecular simulations with polarizable force fields. We study what happens when the surface presents negative charges. At moderately charged surfaces, we observe strong co-ion adsorption and clear specific ion effects at biological concentrations. At high surface charge densities, the co-ions are pushed away from the interface. We predict that Cl- ions can also be excluded from the surface by increasing the concentration of NaI. This ion competition effect (I- versus Cl-) may be relevant for ion-specific partitioning in multiphase systems where polarizable ions accumulate in phases with large surface areas.