Biomonitoring potentially toxic elements in atmospheric particulate matter of greater Dhaka region using leaves of higher plants.

In this study, four different plant species, namely Artocarpus heterophyllus, Mangifera indica, Psidium guajava, and Swietenia mahagoni, were selected from seven different locations to assess the feasibility of using them as a cost-effective alternative for biomonitoring air quality. Atmospheric coarse particulate matter (PM10), soil samples, and leaf samples were collected from residential, industrial, and traffic-congested sites located in the greater Dhaka region. The heavy metal concentrations (Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) in the leaves of the different species, PM10, and soil samples were analyzed. The highest Pb (718 ng/m3) and Zn (15,956 ng/m3) concentrations were found in PM10 of Kodomtoli which is an industrial area. On the other hand, the highest Fe (6,152 ng/m3) and Ni (61.1 ng/m3) concentrations were recorded in the PM10 of Gabtoli, a heavy-traffic area. A significant positive correlation (r = 0.74; p < 0.01) between Pb content in plant leaves and PM fraction was found which indicated that atmospheric PM-bound Pb may contribute to the uptake of Pb by plant leaves. The analysis of the enrichment factor (EF) revealed that soils were contaminated with Cd, Ni, Pb, and Zn. The abaxial leaf surfaces of Psidium guajava growing at the polluted site exhibited up to a 40% decrease in stomatal pores compared to the control site. Saet's summary index (Zc) demonstrated that Mangifera indica had the highest bioaccumulation capacity. The metal accumulation index (MAI) was also evaluated to assess the overall metal accumulation capacity of the selected plants. Of the four species, Swietenia mahagoni (3.05) exhibited the highest MAI value followed by Mangifera indica (2.97). Mangifera indica and Swietenia mahagoni were also found to accumulate high concentrations of Pb and Cr in their leaves and are deemed to be good candidates to biomonitor Pb and Cr contents in ambient air.

Dissolution of cellulose in imidazolium-based double salt ionic liquids.

The dissolution of cellulose in double salt ionic liquids (DSILs) was studied in detail and compared with the dissolution in individual constituent ionic liquids (ILs). The DSILs, [C4mim](CH3CO2)xCl1-x (x is the mole fraction of the single component ILs), were synthesized using acetate and chloride salts of 1-butyl-3-methylimidazolium. These DSILs were then used for the investigation of the solubility of cellulose in the whole mole fraction range. Commercial cellulose (CC) powder, kraft pulp (KP), and prehydrolysis kraft pulp (PHKP) of jute were chosen as cellulose sources. The solubility of cellulose increased with an increasing temperature for [C4mim](CH3CO2)0.6Cl0.4 and with increasing amount of [C4mim]Cl in DSILs. The maximum solubility of CC powder was 32.8 wt% in [C4mim](CH3CO2)0.6Cl0.4 at 100 °C, while for KP and PHKP, solubilities were 30.1 and 30.5 wt%, respectively under the identical condition. Cellulose could be regenerated from the DSILs using water as an antisolvent. Structure, morphology, and thermal stability of the regenerated cellulosic materials were analyzed. DSILs could be recycled >99 % without a discernible change in structure. This work demonstrates that DSILs display enhanced solubility over ILs system and have potential as a chemical processing methodology.

4G mobile phone radiation alters some immunogenic and vascular gene expressions, and gross and microscopic and biochemical parameters in the chick embryo model.

BACKGROUND: The risks to human health have grown over the past 10 years due to the excessive use of mobile phones. OBJECTIVES: The study was designed to determine the harmful effects of 4G mobile phone radiation on the expression of immunogenic and vascular genes and gross, microscopic and biochemical alterations in the development of chicken embryos. METHODS: Sixty individuals in the exposure group were subjected to mobile phones with a specific absorption rate of 1.4 W/kg and a frequency of 2100 MHz positioned at a distance of 12 cm in the incubator for 60 min/night for 14 days. The histopathological examination involved hematoxylin and eosin staining, whereas cresyl violet staining was used to evaluate the condition and number of neurons in the brain. The biochemical parameters of amniotic fluid were analysed using the photometry method, and the expression of VEGF-A and immunity genes (AvBD9, IL6) was measured using the real-time PCR (qPCR) technique. RESULTS: Compared to the control, the exposure group's body weight and length significantly decreased (p < 0.05). Subcutaneous bleeding was seen in the exposure group. Urea, creatinine, alkaline phosphatase, aspartate aminotransferase and alanine aminotransferase levels were all significantly higher than in the control group (p < 0.05). The exposed group showed pathological lesions in the liver and degenerated neurons with lightly stained nuclei in the cerebral cortex. Hyperchromatic neurons were significantly higher in the exposure group (58.8 ± 2.28) compared to the control (6.6 ± 0.44) (p < 0.05). 4G exposure reduced lymphocyte count in the caecal tonsil (86.8 ± 5.38) compared to the control (147.2 ± 9.06) (p < 0.05). Vascular gene mRNA expression was higher, but immune gene expression was lower in the exposed group. CONCLUSION: Exposure to mobile phone radiation may result in gross, microscopic and biochemical changes, as well as alterations in gene expression that could hinder embryonic development.

Urethral rhinosporidiosis: Prolapsing mass from urethra in a Bangladeshi farmer.

Rhinosporidiosis is a chronic granulomatous fungal infection caused by Rhinosporidium seeberi. Usual site of infection is the nasal mucosa & nasopharynx. Male urethra is extremely rare site involving this disease. Here we are reporting a rare case where rhinosporidiosis presented as a prolapsing mass from urethra during voiding.

Cibacron blue 3G-A is a novel inhibitor of Otopetrin 1 (OTOP1), a proton channel.

Otopetrin 1 (OTOP1) is a proton (H+) channel which detects acidic stimuli in sour taste receptor cells and plays some sort of role in the formation of otoconia in the inner ear. Although it is known that zinc ion (Zn2+) inhibits OTOP1, Zn2+ requires high concentrations (mM order) to inhibit OTOP1 sufficiently, and no other inhibitors have been found. Therefore, to identify a novel inhibitor, we screened a chemical library (LOPAC1280) by whole-cell patch clamp recordings, measuring proton currents of heterologously-expressed mouse OTOP1. From the screening, we found that reactive blue 2 inhibited OTOP1 currents. Further evaluations of three analogues of reactive blue 2 revealed that cibacron blue 3G-A potently inhibited OTOP1 currents. Cibacron blue 3G-A inhibited OTOP1 currents in a concentration-dependent manner, and its 50% inhibitory concentration (IC50) and the Hill coefficient were 5.0 µM and 1.1, respectively. The inhibition of OTOP1 currents by cibacron blue 3G-A was less affected by extracellular anion compositions, membrane potentials, and low pH than the inhibition by Zn2+. These results suggest that the inhibition of OTOP1 by cibacron blue 3G-A is neither likely to be a pore-blocking inhibition nor a competitive inhibition. Furthermore, our findings revealed that cibacron blue 3G-A can be used as a novel inhibitor of OTOP1 especially under the conditions in which OTOP1 activity is evaluated such as low pH.

Complications of the suburethral sling in the form of Mini Vaginal Tape (MVT): A case report.

Synthetic sub-urethral sling has become the most widely used technique for the surgical management of stress urinary incontinence. Despite a higher success rate, complications like migration, encrustation, and stone formation have been reported by a mid-urethral sling (MUS). Among mid-urethral sling procedures, mini vaginal tape (MVT) is very popular. As periurethral stone formation and urethrovaginal fistula are very uncommon after MVT, case report on this issue is sparse. The current case report features a 55-year female presented with lower abdominal pain and continuous urinary incontinence, 10 years after the MVT. She was diagnosed as a case of periurethral stone with urinary incontinence due to urethro-vaginal fistula. Our surgical team successfully removed the stone formed by the encrustation of the displaced tape and repaired the fistula. Following the MVT, a high degree of suspicion and long-term follow-up is mandatory for the diagnosis and management of these rare complications.

Preparation of Manganese Oxide Nanoparticles with Enhanced Capacitive Properties Utilizing Gel Formation Method.

Development of efficient and environmentally benign materials is important to satisfy the increasing demand for energy storage materials. Nanostructured transition-metal oxides are attractive because of their variety in morphology, high conductivity, and high theoretical capacitance. In this work, the nanostructured MnO2 was successfully fabricated using a gel formation process followed by calcination at 400 °C (MNO4) and 700 °C (MNO7) in the presence of air. The suitability of the prepared materials for electrochemical capacitor application was investigated using graphite as an electrode substrate. The chemical, elemental, structural, morphological, and thermal characterizations of the materials were performed with relevant techniques. The structural and morphological analyses revealed to be a body-centered tetragonal crystal lattice with a nano-tablet-like porous surface. The capacitive performances of the MNO4- and MNO7-modified graphite electrodes were examined with cyclic voltammetry and chronopotentiometry in a 0.5 M Na2SO4 aqueous solution. The synthesized MNO7 demonstrated a higher specific capacitance (627.9 F g-1), energy density (31.4 Wh kg-1), and power density (803.5 W kg-1) value as compared to that of MNO4. After 400 cycles, the material MNO7 preserves 100% of capacitance as its initial capacitance. The highly conductive network of nanotablet structure and porous morphologies of MNO7 are most likely responsible for its high capacitive behavior. Such material characteristics deserve a good candidate for electrode material in energy storage applications.

Highly robust, novel aluminum counter cation-based monophosphate tungsten bronze electro-catalysts for oxygen evolution in acidic solution.

This study describes the successful synthesis of novel bronze with a low tungsten oxidation state for the efficient electro-catalytic oxidation of water. An extraordinarily robust monophosphate tungsten bronze (MPTB)-modified graphite anode was successfully fabricated for the oxygen evolution reaction (OER) at a thermodynamic potential of 1.23 V in H2SO4 acidic solution. Several Al, Cr and Fe counter-cation-based MPTBs were synthesized by the solution combustion method. Novel Al-based MPTBs calcined at 700 °C in O2 (AlO7) showed almost zero onset overpotential, high current density, high turnover frequency for OER and steady catalysis in repeated use even after 30 weeks. The orthorhombic AlO7 comprising crystallites of 9.89 nm and an indirect band gap (1.89 eV), is an unusually stable MPTB that contains 98% W5+ state stabilized with the Al3+ counter cation. The catalysis decreases as the ratio of W5+ : W6+ in MPTBs decreases and [410] and [601] facets play main roles in the first H2O association and nucleophilic attack of the second H2O molecule on the catalyst surface. Thus, MPTBs can be non-noble metal anode materials for robust acidic H2O electrolyzers.

Electrode surface modification of graphene-MnO2 supercapacitors using molecular dynamics simulations.

In this study, molecular dynamics (MD) simulations have been performed to explore the variation of ion density and electric potential due to electrode surface modification. Two different surface morphologies, having planer and slit pore with different conditions of surface charge, have been studied for graphene-MnO2 surface using LAMMPS. For different pore widths, the concentration of ions in the double layer is observed to be very low when the surface of the graphene-MnO2 electrode is charged. With a view to identify the optimal pore size for the simulation domain considered, three different widths for the nano-slit type pores and the corresponding ion-ion interactions are examined. Though this effect is negligible for pores with 9.23 and 3.55 Å widths, a considerable increase in the ionic concentration within the 7.10 Å pores is observed when the electrode is kept neutral. The edge region of these nano-slit pores leads to effective energy storage by promoting ion separation and a significantly higher charge accumulation is found to occur on the edges compared to the basal planes. For the simulation domain of the present study, partition coefficient is maximum for a pore size of 7.10 Å, indicating that the ions' penetration and movement into nano-slit pores are most favorable for this optimum pore size for MnO2-graphene electrodes with aqueous NaCl electrolyte. Graphical Abstract The importance of understanding the commercial feasibility of supercapacitor material has made qualitatively predicting the optimized electrode structure one of the main targets of energy related researches. While great progress has been made in recent years, a coherent theoretical picture of the optimized electrode structure remains elusive. This article discusses the most favorable design of supercapacitor electrode for ion-electrode interaction.

Temperature dependence of differential capacitance in the electric double layer.Symmetric valency 1:1 electrolytes.

The differential capacitance of an electric double layer formed by an aqueous solution of KNO3 on a glassy carbon electrode is measured by impedance analysis at constant frequency. Results are obtained at electrolyte concentrations of 0.1 mol/dm3, 0.5 mol/dm3, and 1.0 mol/dm3, and at a series of temperatures, viz., 288 K, 298 K, 308 K, 318 K, and 328 K. The differential capacitance envelopes reveal a rich, complex pattern of maxima, minima, and local minima, whose magnitude and position change with a change in solution concentration. At the two lower concentrations, the temperature dependence of the capacitance, for example, at zero electrode potential, shows an alternating positive-negative behavior, while at the highest concentration of 1.0 mol/dm3, the slope of the differential capacitance-electrode potential curve is always positive. The experimental results are supplemented by a numerical grand canonical Monte Carlo simulation study of a restricted primitive model double layer but with an off-center cationic charge achieved by displacing the charge center from the ion sphere center toward its surface. The simulations, performed at the electrolyte concentration of 1.0 mol/dm3 and constant cation charge center displacement, and at varying electrode potentials and temperatures, show, in general, a negative temperature dependence of the differential capacitance. However, this temperature dependence can also be positive for a negative electrode charge and for a sufficiently large gradient of the cation charge center displacement with temperature. This feature is seen to be associated with an increase in the entropy of formation of the double layer.

Frontier performance of in situ formed α-MnO2 dispersed over functionalized multi-walled carbon nanotubes covalently anchored to a graphene oxide nanosheet framework as supercapacitor materials.

α-MnO2 has been recognized as a potential material for supercapacitor applications because of its abundance, cost-effectiveness, environmental-benign nature and high theoretical specific capacitance (C sp) of 1370 F g-1. In this study, we succeeded for the first time to achieve the theoretical C sp with 3D multi-walled carbon nanotubes (MWCNTs) horizontally dispersed on 2D graphene oxide (GO) nanosheet framework-supported MnO2 ternary nanocomposites synthesized by a simple precipitation method. The in situ formation of α-MnO2 and GO, and the growth of 3D MWCNT/GO framework took place simultaneously in a strong acidic suspension containing functionalized-MWCNTs, graphite, NaNO3 and KMnO4. Characterizations of the composites synthesized by varying % wt MWCNTs were performed with state-of-the-art techniques. These composites were characterized to be semi-crystalline and mesoporous in nature, and the scrupulous analyses of field emission scanning electron microscopic images showed MnO2 nano-flower distributed over 3D MWCNTs dispersed-on-GO-nanosheet frameworks. These composites deposited on a graphite electrode exhibited an ideal supercapacitive behavior in an Na2SO4 solution measured via cyclic voltammetry and chronopotentiometry. Optimum contents of MnO2 and MWCNTs in the composites showed a maximum C sp of 1380 F g-1 with satisfactory energy and power densities compared in the Ragone plot. An ascending trend of C sp against the charge-discharge cycle number studied for 700 cycles was noticed. Well-dispersion of α-MnO2 nanoparticles throughout 3D MWCNTs covalently-anchored to the GO nanosheet framework is discussed to aid in achieving the frontier C sp of MnO2.

In vitro analysis of genetically distinct Chlamydia pecorum isolates reveals key growth differences in mammalian epithelial and immune cells.

Chlamydia (C.) pecorum is an obligate intracellular bacterium that infects and causes disease in a broad range of animal hosts. Molecular studies have revealed that this pathogen is genetically diverse with certain isolates linked to different disease outcomes. Limited in vitro or in vivo data exist to support these observations, further hampering efforts to improve our understanding of C. pecorum pathogenesis. In this study, we evaluated whether genetically distinct C. pecorum isolates (IPA, E58, 1710S, W73, JP-1-751) display different in vitro growth phenotypes in different mammalian epithelial and immune cells. In McCoy cells, shorter lag phases were observed for W73 and JP-1-751 isolates. Significantly smaller inclusions were observed for the naturally plasmid-free E58 isolate. C. pecorum isolates of bovine (E58) and ovine origin (IPA, W73, JP-1-751) grew faster in bovine cells compared to a porcine isolate (1710S). C. pecorum isolates could infect but appear not able to complete their developmental cycle in bovine peripheral neutrophil granulocytes. All isolates, except 1710S, could multiply in bovine monocyte-derived macrophages. These results reveal potentially important phenotypic differences that will help to understand the pathogenesis of C. pecorum in vivo and to identify C. pecorum virulence factors.

Sustainable Generation of Ni(OH)2 Nanoparticles for the Green Synthesis of 5-Substituted 1H-Tetrazoles: A Competent Turn on Fluorescence Sensing of H2O2.

A mutually correlated green protocol has been devised that originates from a sustainable production of ß-Ni(OH)2 nanoparticles which is used for an efficient catalytic synthesis of versatile substituted tetrazoles, under mild reaction conditions in water via a simple, one-pot, eco-friendly method. The synthesis is followed by derivatization into a highly fluorescence active compound 9-(4-(5-(quinolin-2-yl)-1H-tetrazol-1-yl)phenyl)-9H-carbazole that can be used at tracer concentrations (0.1 µM) to detect as well as quantify hydrogen peroxide down to 2 µM concentration. The nanocatalyst was synthesized by a simple, proficient, and cost-effective methodology and characterized thoroughly by UV-vis absorption and Fourier transform infrared spectra, N2 adsorption/desorption, high resolution transmission electron microscopy, powder X-ray diffraction pattern, field emission scanning electron microscopy, and thermogravimetric analysis. Broad substrate scope, easy handling, higher efficiency, low cost, and reusability of the catalyst are some of the important features of this heterogeneous catalytic system. The strong analytical performance of the resultant derivative in low-level quantification of potentially hazardous hydrogen peroxide is the key success of the overall green synthesis procedure reported here.

Development and evaluation of rapid novel isothermal amplification assays for important veterinary pathogens: Chlamydia psittaci and Chlamydia pecorum.

BACKGROUND: Chlamydia psittaci and Chlamydia pecorum are important veterinary pathogens, with the former also being responsible for zoonoses, and the latter adversely affecting koala populations in Australia and livestock globally. The rapid detection of these organisms is still challenging, particularly at the point-of-care (POC). In the present study, we developed and evaluated rapid, sensitive and robust C. psittaci-specific and C. pecorum-specific Loop Mediated Isothermal Amplification (LAMP) assays for detection of these pathogens. METHODS AND MATERIALS: The LAMP assays, performed in a Genie III real-time fluorometer, targeted a 263 bp region of the C. psittaci-specific Cps_0607 gene or a 209 bp region of a C. pecorum-specific conserved gene CpecG_0573, and were evaluated using a range of samples previously screened using species-specific quantitative PCRs (qPCRs). Species-specificity for C. psittaci and C. pecorum LAMP targets was tested against DNA samples from related chlamydial species and a range of other bacteria. In order to evaluate pathogen detection in clinical samples, C. psittaci LAMP was evaluated using a total of 26 DNA extracts from clinical samples from equine and avian hosts, while for C. pecorum LAMP, we tested a total of 63 DNA extracts from clinical samples from koala, sheep and cattle hosts. A subset of 36 C. pecorum samples was also tested in a thermal cycler (instead of a real-time fluorometer) using newly developed LAMP and results were determined as an end point detection. We also evaluated rapid swab processing (without DNA extraction) to assess the robustness of these assays. RESULTS: Both LAMP assays were demonstrated to species-specific, highly reproducible and to be able to detect as little as 10 genome copy number/reaction, with a mean amplification time of 14 and 24 min for C. psittaci and C. pecorum, respectively. When testing clinical samples, the overall congruence between the newly developed LAMP assays and qPCR was 92.3% for C. psittaci (91.7% sensitivity and 92.9% specificity); and 84.1% for C. pecorum (90.6% sensitivity and 77.4% specificity). For a subset of 36 C. pecorum samples tested in a thermal cycler using newly developed LAMP, we observed 34/36 (94.4%) samples result being congruent between LAMP performed in fluorometer and in thermal cycler. Rapid swab processing method evaluated in this study also allows for chlamydial DNA detection using LAMP. DISCUSSION: In this study, we describe the development of novel, rapid and robust C. psittaci-specific and C. pecorum-specific LAMP assays that are able to detect these bacteria in clinical samples in either the laboratory or POC settings. With further development and a focus on the preparation of these assays at the POC, it is anticipated that both tests may fill an important niche in the repertoire of ancillary diagnostic tools available to clinicians.

Heterogeneous Route for the One-Pot Synthesis of N-Arylamides from Aldoximes and Aryl Halides Using the CuO/Carbon Material.

Metal oxide nanoparticles (NPs) stabilized by porous carbon materials (PCMs) are very promising for catalysis. In this work, monodispersed small and stable copper oxide (CuO) NPs were prepared with an average size of 10-20 nm without using any capping agent and then these NPs were encapsulated into porous carbon. The chemical and structural properties of the CuO/PCM material were characterized by powder X-ray diffraction, electron microscopy, Raman spectroscopy, scanning electron microscopy, transmission electron microscopy, and nitrogen sorption. The obtained CuO/PCM nanocatalytic system has been used for the synthesis of N-arylamides from the reaction of aldoximes and aryl halides. Generally, copper(II) salt was used for the preparation of amides from aldoximes using some ligands and bases, but harsh reaction condition, stoichiometric amount of metal, and lack of recyclability limit their applications in industry. An alternative method is the use of heterogeneous catalysts. More importantly, these heterogeneous catalysts could be easily recycled and reused, showing potential application in organic synthesis.

Enhanced catalytic reduction of oxygen at tantalum deposited platinum electrode.

A tantalum deposited platinum electrode that offers an enhanced catalytic four-electron reduction of oxygen over the bare platinum electrode in acidic solution is explored.

Clinical anatomy of the head region of the black bengal goat in Bangladesh / Anatomía clínica de la región de la cabeza de la cabra negra bengal en Bangladesh

The study involved the measurements of some clinically important landmarks for regional anesthesia in the maxillary and mandibular regions of head of fifty Black Bengal (BB) goats. The distance from facial tuberosity to the infra-orbital canal and from the latter to the root of the alveolar tooth directly ventral to it were 1.85 cm and 1.75 cm respectively. Both the distances from facial tuberosity to infra-orbital canal and from infra-orbital canal to the root of the alveolar tooth are of clinical important even in live animal as a guide for tracking infra-orbital nerve because of facial tuberosity. The distance between the lateral end of the alveolus of the incisor tooth to the mental foramen was 2.11 cm and are from the mental foramen to the caudal mandibular border was 11.69 cm and important for the regional anesthesia of mental nerve. The length and maximum height of the mandibles were 14.21 cm and 8.83 cm respectively. The distance from Caudal border of mandible to below mandibular foramen was 1.47 cm, while the distance from the mandibular foramen to the base of the mandible, Caudal border of mandibular to the level of mandibular foramen and mandibular foramen to border of mandibular angle were 3.64cm, 0.90 cm and 2.65 cm respectively. Parameters regarding mandible are of c linical important landmarks and will be guide for the regional anesthesia of mandibular nerve block. However, these data was discussed with regard to their application in proper tracking of infra-orbital, mental and mandibular nerves in aid of regional anesthetic procedures for the clinical affection around the head of the Black Bengal goat.

El estudio incluyó la medición de algunos puntos anatómicos de importancia clínica para la anestesia regional en las regiones superior e inferior de la cabeza de cincuenta cabras Negras de Bengal (BB). La distancia desde la tuberosidad facial hasta el canal infraorbitario y de éste a la raíz del diente alveolar directamente ventral a él fueron 1,85 cm y 1,75 cm, respectivamente. Tanto las distancias desde la tuberosidad facial hasta el canal infraorbitario y desde el canal infraorbitario a la raíz del diente alveolar fueron importancia clínica en animales vivos como una guía para el seguimiento del nervio infraorbitario a través de la tuberosidad facial. La distancia entre el extremo lateral de los alvéolos de los dientes incisivos al foramen mental fue de 2,11 cm y desde el foramen mental al borde mandibular caudal fue 11,69 cm y es importante para la anestesia regional del nervio mentoniano. La longitud y la altura máxima de las mandíbulas fueron 14,21 cm y 8,83 cm respectivamente. La distancia desde el borde caudal de la mandíbula por debajo del foramen mandibular fue de 1,47 cm, mientras que la distancia desde el foramen mental hasta la base de la mandíbula, desde el borde caudal de la mandíbula a nivel del foramen mandibular y del foramen mandibular hasta el borde del ángulo mandibular fueron 3,64cm , 0,90 cm y 2,65 cm, respectivamente. Los parámetros en relación con la mandíbula son puntos anatómicos de importancia clínica y sirven de guía para la anestesia regional del bloqueo del nervio mandibular. No obstante, estos datos fueron discutidos en relación a su aplicación en el seguimiento adecuado de las infraestructuras de los nervios infraorbitario, mental y mandibular en ayuda a procedimientos anestésicos regionales para el uso clínico alrededor de la cabeza de cabra de Bengal Negra.

Stability of superoxide ion in imidazolium cation-based room-temperature ionic liquids.

The stability of superoxide ion (O(2)(*-)) generated chemically by dissolving KO(2) in dried dimethyl sulfoxide solutions containing imidazolium cation [e.g., 1-ethyl-3-methylimidazolium (EMI(+)) and 1-n-butyl-2,3-dimethylimidazolium (BMMI(+))] based ionic liquids (ILs) was investigated with UV-visible spectroscopic, NMR, and voltammetric techniques and an ab initio molecular orbital calculation. UV-visible spectroscopic and cyclic voltammetric measurements reveal that the O(2)(*-) species reacts with BMMI(+) and EMI(+) cations of ILs to form hydrogen peroxide. The pseudo first order rate constant for the reaction of BMMI(+) and O(2)(*-) species was found to be about 2.5 x 10(-3) s(-1). With a molecular orbital calculation, the O(2)(*-) species is understood to attack the 2-position (C-2) of the imidazolium ring (i.e., BMMI(+)) to form an ion pair complex in which one oxygen atom is bounded to C-2 and the other to the hydrogen atom of -CH(3) group attached to C-2. Eventually, the ion pair complex of BMMI(+) cation and O(2)(*-) species undergoes a ring opening reaction as evidenced with (1)H NMR measurement.

Water electrolysis: an excellent approach for the removal of water from ionic liquids.

An electrochemical system based on platinum cathode and glassy carbon anode was assembled for a successful removal of water from ionic liquids via the water electrolysis strategy.

Electrochemical, HPLC and electrospray ionization mass spectroscopic analyses of peroxycitric acid coexisting with citric acid and hydrogen peroxide in aqueous solution.

We successfully determined the molecular structure of peroxycitric acid (PCA) coexisting in the aqueous equilibrium mixture with citric acid (CA; 1,2,3-tricarboxylic-2-hydroxy propane) and hydrogen peroxide (H(2)O(2)) by a combined use of reversed-phase HPLC (RP-HPLC), potentiometric, hydrodynamic chronocoulometric (HCC) and electrospray ionization mass spectroscopic (ESI-MS) methods. Firstly, the RP-HPLC was employed to separate CA, PCA and H(2)O(2) coexisting in the equilibrium mixture and the concentration of CA consumed (DeltaC(CA)) in the formation of PCA that was evidenced to be fairly stable during the RP-HPLC measurement was quantitatively measured based on the standard calibration curve of CA. Secondly, the total oxidant concentration (C(Ox)) corresponding to peroxycarboxylic (-COOOH) group in PCA in the equilibrium mixture was determined using potentiometric measurement. The ratio of C(Ox)/DeltaC(CA) was found to be 1.07, which indicates that only one -COOH group in CA molecule is oxidized to the corresponding -COOOH group in PCA molecule. Thirdly, using the HCC technique the diffusion coefficient of PCA, which could be electroreduced at a more positive potential by 1.0 V than the coexisting H(2)O(2), was independently measured as 0.3 x 10(-5)cm(2)s(-1) and at the same time, by considering DeltaC(CA) as the concentration of PCA, the number of electrons (n) required for the reduction of PCA was determined to be 2. The result obtained from RP-HPLC and HCC, i.e., n=2 which is equivalent to one -COOOH group in PCA, is in agreement with that obtained from the combination of RP-HPLC and potentiometric measurements. Finally, the structure of PCA was proposed to contain one -COOOH group with a molecular mass of 208 confirmed by negative ion ESI-MS method. A probable molecular structure of PCA was discussed.