A comparative study of α-Ni(OH)2 and Ni nanoparticle supported ZIF-8@reduced graphene oxide-derived nitrogen doped carbon for electrocatalytic ethanol oxidation.

Ethanol electrooxidation is an important reaction for fuel cells, however, the major obstacle to ethanol electrocatalysis is the splitting of the carbon-carbon bond to CO2 at lower overpotentials. Herein, a ZIF-8@graphene oxide-derived highly porous nitrogen-doped carbonaceous platform containing zinc oxide was attained for supporting a non-precious Ni-based catalyst. The support was doped with the disordered α-phase Ni(OH)2 NPs and Ni NPs that are converted to Ni(OH)2 through potential cycling in alkaline media. The Ni-based catalysts exhibit high electroactivity owing to the formation of the NiOOH species which has more unpaired d electrons that can bond with the adsorbed species. From CV curves, the EOR onset potential of the α-Ni(OH)2/ZNC@rGO electrode is strongly shifted to negative potential (Eonset = 0.34 V) with a high current density of 8.3 mA cm-2 relative to Ni/ZNC@rGO. The high catalytic activity is related to the large interlayer spacing of α-Ni(OH)2 which facilitates the ion-solvent intercalation. Besides, the porous structure of the NC and the high conductivity of rGO facilitate the kinetic transport of the reactants and electrons. Finally, the catalyst displays a high stability of 92% after 900 cycles relative to the Ni/ZNC@rGO and commercial Pt/C catalysts. Hence, the fabricated α-Ni(OH)2/ZNC@rGO catalyst could be regarded as a potential catalyst for direct EOR in fuel cells.

Solar-driven seawater desalination via plasmonic hybrid MOF/polymer and its antibacterial activity.

In recent years, solar seawater desalination has been considered to be a promising and cost-effective technique to produce clean sources for water treatment and water deficiency. In addition, this technique shows high photothermal conversion efficiency by solar collectors to transfer solar energy into heat and the transformation of molecules in the capillaries of solar evaporators. In this study, we report the preparation of graphene-supported MIL-125 with polyurethane foam (MGPU) for solar steam generation. We modified MGPU by using the plasmonic nanoparticles of Ag and a polymer of polyaniline to increase the evaporation rate. Polyurethane foam can float on the surface of water and self-pump water by its hydrophilic porous structure, superior thermal insulation capabilities, and easy fabrication. MIL-125 has a high salt rejection and higher water permeability. It can reduce the affinity between water molecules and the pore surface of membrane, making it simple for water molecules to move through the pores. GO is a great alternative for steam generation applications since it exhibits broad-band light. The strong solar absorption, photothermal conversion efficiency, and photoreaction efficiency are enhanced by the use of silver nanoparticles in the photoreaction. The salt resistance capability is enhanced in saline water in the presence of polyaniline in a composite. Under one solar irradiation, the Ag/PANI/GO@MIL-125 (Ag-PMG) nanocomposite demonstrates an average 1.26 kg m2 h-1 rate of evaporation and an efficiency as high as 90%. The composite exhibits remarkable stability and durability after more than 10 cycles of use without a noticeable decrease in activity. In addition, the composite exhibits excellent organic dye removal from contaminated water and generates pure condensed freshwater. The antibacterial photoactivity of the photocatalysts was examined against B. subtilis and E. coli. The results demonstrate that Ag-PMG shows higher antibacterial activity than MIL-125 and PMG. It was shown that the presence of rGO, PANI, and Ag in the sample enhances the antimicrobial activity.

Muonic atom spectroscopy with microgram target material.

Muonic atom spectroscopy-the measurement of the x rays emitted during the formation process of a muonic atom-has a long standing history in probing the shape and size of nuclei. In fact, almost all stable elements have been subject to muonic atom spectroscopy measurements and the absolute charge radii extracted from these measurements typically offer the highest accuracy available. However, so far only targets of at least a few hundred milligram could be used as it required to stop a muon beam directly in the target to form the muonic atom. We have developed a new method relying on repeated transfer reactions taking place inside a 100 bar hydrogen gas cell with an admixture of 0.25% deuterium that allows us to drastically reduce the amount of target material needed while still offering an adequate efficiency. Detailed simulations of the transfer reactions match the measured data, suggesting good understanding of the processes taking place inside the gas mixture. As a proof of principle we demonstrate the method with a measurement of the 2p-1s muonic x rays from a 5  µ g gold target.

Translation, cultural adaptation, and evaluation of the psychometric properties of an Arabic diabetes distress scale: A cross sectional study from Saudi Arabia.

OBJECTIVES: To translate, validate, and adapt the diabetes distress scale (DDS)-17 to a Saudi Arabian (SA) DDS (SADDS-17). Also, to evaluate the psychometric properties of the newly adapted SADDS-17. METHODS: This was a cross-sectional study evaluating the psychometric properties of the DDS. The DDS was translated using the forward-backward translation from English to Arabic at King Saud University Medical City (KSUMC), Riyadh, Saudi Arabia, in January 2016. Statistical analyses included exploratory factor analysis, internal consistency, testretest reliability, and construct validity. Moreover, contingent validity was evaluated using hospital anxiety and depression scale, visual analogue scale, and the World Health Organization quality of life assessment instrument. RESULTS: A total of 109 participants were included in this study. The exploratory factor analysis of our Arabic scale supported the original DDS with 4 sub-scales. Correlations ranged from 0.376 to 0.718 for items in regimen-related distress, 0.327 to 0.533 for items in emotional burden, 0.413 to 0.722 for items in physician-related distress, and 0.492 to 0.556 for items in interpersonal distress. The Cronbach's alpha value of the SADDS was 0.848 for the total scale. The test-retest reliability value was 0.78. CONCLUSION: Our SADDS is a valid and reliable instrument for detecting diabetes distress among Saudi Arabian patients with type 2 diabetes.

The Emergency surgery score (ESS) accurately predicts outcomes of emergency surgical admissions at a Saudi academic health center.

BACKGROUND: The emergency surgery score (ESS) has emerged as a tool to predict outcomes in emergency surgery (EGS) patients. Our study examines the ability of ESS to predict outcomes in EGS admissions. METHODS: All EGS admissions to King Saud University Medical City (KSUMC) from January 2017 to October 2019 were included. ESS was calculated for each patient. Correlations between ESS and 30-day mortality and complications were evaluated. RESULTS: 1607 patients were included. 30-day mortality rate was 2.2% while complication rate was 18.7%. Mortality increased as ESS increased, from 0.3% for ESS≤2, to 30.1% for ESS >10, with a c-statistic of 0.88. Complication rates were 2.2%, 40%, and 100% at ESS of 0, 6, and 15, respectively, with a c-statistic of 0.82. CONCLUSIONS: ESS accurately predicted outcomes at our tertiary center. ESS could be useful in identifying high risk EGS admissions and in benchmarking quality of care across Saudi institutions.

Adsorption of Cr(VI) and As(V) ions by modified magnetic chitosan chelating resin.

Cross-linked magnetic chitosan anthranilic acid glutaraldehyde Schiff's base (CAGS) was prepared for adsorption of both As(V) and Cr(VI) ions and their determination by ICP-OES. Prepared cross-linked magnetic CAGS was investigated by means of SEM, FTIR, wide angle X-ray diffraction (WAXRD) and TGA analysis. The adsorption properties of cross-linked magnetic CAGS resin toward both As(V) and Cr(VI) were evaluated. Various factors affecting the uptake behavior such as pH, temperature, contact time, initial concentration of metal ions, effect of other ions and desorption were studied. The equilibrium was achieved after about 110 min and 120 min for As(V) and Cr(VI), respectively at pH=2. The adsorption kinetics followed the mechanism of the pseudo-second order equation for all systems studied, evidencing chemical sorption as the rate-limiting step of adsorption mechanism and not involving a mass transfer in solution. The equilibrium data were analyzed using the Langmuir, Freundlich, and Tempkin isotherm models. The best interpretation for the equilibrium data was given by Langmuir isotherm, and the maximum adsorption capacities were 58.48 and 62.42 mg/g for both Cr(VI) and As(V), respectively. Cross-linked magnetic CAGS displayed higher adsorption capacity for Cr(VI). The adsorption capacity of the metal ions increased with increasing temperature under optimum conditions in case of Cr(VI), but decreased in case of As(V). The metal ion-loaded cross-linked magnetic CAGS were regenerated with an efficiency of greater than 88% using 0.2M sodium hydroxide (NaOH).

Colorimetric determination of sympathomimetic amines methyldopa and noradrenaline.

The chromogenic reagent p-dimethylaminocinnamaldehyde (PDAC) is introduced for the determination of the sympathomimetic amines methyldopa and noradrenaline. The method is based on measurement of the orange color developed when the alkaline solution of methyldopa and noradrenaline is allowed to react with PDAC at pH 5.0. The color developed obeys Beer's law in the concentration range 0.1-1.5 mL of 2 X 10(-3)M solution of noradrenaline and methyldopa. The results are compared with those obtained with another chromogenic reagent, p-dimethylaminobenzaldehyde (PDAB). Determinations on dosage forms of the drugs, using PDAC and PDAB reagents, agreed well with results of determinations by official pharmacopoeial methods.

Preparation of alkoxyquinoline derivatives and their evaluation as potential central nervous system stimulants.

A variety of substituted amides of 6,7-dimethoxy-2-hydroxyquinoline-3-carboxylic acid were synthesized. Three of these compounds, tested as potential central nervous system stimulants, showed no marked biological activity.

Polarographic behaviour and determination of some penicillins after bromometric oxidation.

The direct current polarographic behaviour of the bromometric oxidation product of certain penicillins has been investigated. The oxidized products give a well defined cathodic wave with E1/2 = 0.6 V vs saturated calomel electrode (SCE). The nature of the wave and the electrode reaction have been evaluated. A procedure was developed for investigation of the penicillins either in the pure state or in dosage forms. The results were compared with those obtained with the official methods.

Simultaneous spectrophotometric determination of amodiaquine-primaquine mixtures in dosage forms.

Using 0.1N hydrochloric acid as solvent, mixtures of amodiaquine and primaquine have been measured at 282 and 342 nm. The concentration of each can then be calculated by solving 2 simultaneous equations. Excellent recoveries from authentic samples were obtained and the method proved suitable for routine analysis.

Spectrophotometric and titrimetric determination of certain adrenergic drugs, using organic brominating agents.

New oxidimetric titrants, bromamine T, dibromohydantoin, N-bromophthalimide, and N-bromosuccinimide, were applied to the determination of ephedrine.HCl, norephedrine.HCl, and methyldopa. Direct potentiometric and visual indicator titration methods as well as back-titration procedures have been developed for their determination. Oxidation of ephedrine and norephedrine produces benzaldehyde, which is extracted from pH 11.0 phosphate buffer with ether or hexane and determined spectrophotometrically at 242 nm. Beer's law is obeyed in the concentration range from 0.2 to 2 mg ephedrine.HCl and from 0.15 to 1.9 mg norephedrine.HCl. Methyldopa is determined titrimetrically and spectrophotometrically. In addition, this drug acts as a self-indicator: Solutions change from colorless to red, which gradually disappears with continuous addition of brominating agent and shaking. Phosphate buffer is used to produce adrenochrome, characterized by its pink color which can be measured at 485 nm in a working range from 40 to 650 micrograms.

Colorimetric determination of certain phenol derivatives in pharmaceutical preparations.

Simple colorimetric methods are reported for determining both acetaminophen and oxyphenbutazone. These methods are based on coupling between the phenolic compound and the diazonium salts of both sulfanilic acid and p-nitroaniline; the optimum conditions for the reactions were carefully studied. For acetaminophen, the reaction products with diazosulfanilic acid and diazo-p-nitroaniline show maximum absorbance at 480 and 425 nm, respectively. The mean percentage recoveries for authentic samples were 99.5 +/- 1.1 and 100.6 +/- 0.66, respectively (P = 0.05). For oxyphenbutazone, the obtained colors showed maxima at 385 nm with diazosulfanilic acid and 490 nm with diazo-p-nitroaniline reactions. The mean percentage recoveries for authentic samples were 99.8 +/- 0.27 and 100.1 +/- 0.57, respectively (P = 0.05). The proposed methods were successfully applied to the analysis of commercial preparations; results were statistically compared with those of other methods.

Spectrophotometric determination of piperazine and its salts in pharmaceuticals.

A spectrophotometric determination of piperazine and some of its salts is described. The method depends on the UV measurement of the N-nitroso derivatives formed by the interaction of piperazine with nitrous acid. The chromophore is developed by heating the reaction mixture at 80 degrees C for 15 min, at pH 2.3--2.6. Beer's law is obeyed in the range 1--15 micrograms/mL.

Evaluation of certain pharmaceuticals with dibromodimethylhydantoin. Part 2: Determination of analgesics.

1,3-Dibromodimethylhydantoin (DBH) is a stable dihalogen reagent. It can be used as an analytical reagent for certain analgesics. It gives stoichiometric results by direct titration in acid medium. The end point is detected visually or potentiometrically. Also spectrophotometric titrations have been attempted at 345 nm. In all cases the results of the analysis of the drugs studied either in the pure state or in their dosage forms comply with those given by N-bromo succinimide (NBS) and by the official methods, however this application is distinguished by simplicity and accuracy.