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Tungsten carbide-based nano-catalysts (Ni-WC, Co-WC and NiCo-WC) and molybdenum carbide-based nano-catalysts (Ni-MoC, Co-MoC and NiCo-MoC) were synthesised using a carbothermal reduction method. X-ray diffraction, scanning electron microscopy coupled with electron dispersive spectroscopy, x-ray photoelectron spectroscopy and cyclic voltammetry were used to evaluate the prepared electrocatalysts. The cyclic voltammetry results showed that Ni-WC coated electrode displayed the best hydrogen evolution reaction catalytic activity with the lowest overpotential of 1.421 V at a current density of 10 mA cm−2, and a Tafel slope of 135 mV dec−1 which is marginally lower than the benchmark Pt/C coated electrodes. Ni-MoC and Co-MoC coated electrocatalysts also produced current more effectively with a change in potential as compared to the Pt/C coated electrode. The durability test showed Co-WC, NiCo-WC and Ni-MoC coated electrodes to have high stability within a wide range of current densities. [ABSTRACT FROM AUTHOR]

The kinetics of dehydroxylation of South African kaolin revealed that both the inner and the surface hydroxyl groups disappear according to first order kinetics, however, the surface group disappeared faster than the inner groups, showing that diffusion control kinetics is also important. The temperature dependent transformations of the kaolin was measure by means of fractional conversion of the ratios between AlO6:AlO4 and Si-O-Al:Si-O-Si, which showed kobs values 0.0168 s-1 and 0.0089 s-1 for the transformation to the spinel phase and values of 0.0165 s-1 and 0.0156 s-1 for the transformation to mullite respectively. The pozzolanic activities of the kaolin calcined at different temperatures showed a maximum pozzolanic activity when the kaolin is calcined at 650°C and the pozzolanic activity for mullite is even less than for the uncalcined kaolin. XPS revealed that the atomic ratio between Si and Al did not change from kaolin to metakaolin (Si:Al = ca. 1.2) however the mullite showed a atomic ratio of Si:Al = 1.52, implying that some deallumination occurred during calcination at high temperatures.

Nuclear magnetic resonance measurements confirm that, as expected, the mer isomer of tris(β-diketonato) cobalt(III) complexes is more stable (mer isomers are more stable because they are less affected by steric hindrance and they have lower dipoles). An excess of the mer isomer or only the mer isomer is experimentally observed. The existence of both fac and mer isomers is predicted by density functional theory calculations. At room temperature, the nuclear magnetic resonance peaks of phenyl-containing mer complexes are broad due to the intermediate rotation of bulky phenyl groups resulting in only the average orientation of the non-equivalent protons in the mer complexes. However, upon heating to 55°C (thus speeding up the rotation) or cooling to −50°C (slowing down the rotation), this broad peak is resolved into three sets of carbon peaks appearing in the 13C NMR spectrum, as well as splitting of the ¹H NMR peaks for the non-equivalent protons in the mer isomer. In solid-state 13C NMR the aromatic rings do not rotate, resulting in the splitting of all the 13C NMR peaks. Two sets of well-defined peaks are observed for the fluorine-containing compound [Co(CF3COCHCOCPh)3] in both the 13C and 19F NMR spectra, indicating that both the fac and mer isomers are present with a ratio of fac:mer = 0.1:1. The X-ray photoelectron spectroscopy measured binding energy of the Co 2p3/2 photoelectron lines are influenced by the subtle electronic (electron-donating or electron-withdrawing) properties of the R groups on the β-diketonato ligands. Various relationships are established between the binding energy of Co 2p3/2 and several physical and density functional theory–calculated properties, confirming good electronic communication (the measurable electronic effect that a molecular fragment has on the physical properties of another molecular fragment in the molecule) of the substituent groups through the pseudo aromatic system of the β-diketonato backbones to the metal. [ABSTRACT FROM AUTHOR]

Nano γ-alumina-supported transition metal-based mono- (Pd 0/γ-Al2O3 or Co111/γ-Al2O3) and bimetallic catalysts (Pd0 Co111 /γ-Al2O3), were prepared by wet impregnation, oxidation and in situ reduction of the palladium. The palladium(II) acetate [Pd113 (OOCCH3)6], cobalt(II) acetate [Co11 (OOCCH3)2]•4H2O and palladium, cobalt bridging tetraacetate [Pd11 Co11 (OOCCH3)4]•H2O•2CH3COOH, were used as catalyst precursors to prepare a 7.4 % mol catalyst/support loading. The oxidation states of these activated catalysts were studied by XPS. These catalysts were evaluated for hydrogenation of cinnamaldehyde in a biphasic reaction under 3 MPa of hydrogen at 80°C. The Pd0/-Al2O3 selectively catalyzed the hydrogenation of C=C bond in cinnamaldehyde to form phenylpropanol (100%). In contrast, catalysiswith Pd0 Co111/γ-Al2O3 hydrogenated both C=C and C=O bonds consecutively, forming 65 % phenylpropanal and 35 % phenylpropanol with TOF = 47.2 h-1 . No reaction occurred when Co111/γ-Al2O3 was used. [ABSTRACT FROM AUTHOR]

The metathesis of 1-hexene and (E)-anethole in the presence of Grubbs 2nd generation catalyst was monitored by in situ 1H NMR spectroscopy at different temperatures (15 °C, 25 °C, and 45 °C) and anethole mol fractions (XAnethole ≈ 0.17, 0.29, 0.5, 0.71, 0.83). Time traces confirmed the instantaneous formation of (E)-1-(4-methoxyphenyl)-1-hexene, the cross-metathesis product. A maximum concentration of (E)-1-(4-methoxyphenyl)-1-hexene is reached fairly fast (the time depending on the reaction conditions), and this is followed by a decrease in the concentration of (E)-1-(4-methoxyphenyl)-1-hexene due to secondary metathesis. The maximum concentration of (E)-1-(4-methoxyphenyl)-1-hexene was more dependent on the XAnethole than the temperature. The highest TOF (3.46 min−1) was obtained for the reaction where XAnethole was 0.16 at 45 °C. The highest concentration of the cross-metathesis product was however achieved after 6 min with an anethole mol fraction of 0.84 at 25 °C. A preliminary kinetic study indicated that the secondary metathesis reaction followed first order kinetics. [ABSTRACT FROM AUTHOR]

The general synthetic strategy towards water-soluble biodegradable drug carriers and the properties that they must have are discussed. The syntheses of water-soluble biodegradable copolymers of lysine and aspartic acid as potential drug-delivering devices, having amine-functionalised side chains are then described. Covalent anchoring of carboxylic acid derivatives of the antineoplastic ferrocene and photodynamically active phthalocyanine moieties to the amine-containing drug carrier copolymers under mild coupling conditions has been achieved utilising the coupling reagent O-benzotriazolyl-N,N,N′,N′-tetramethyluronium hexafluorophosphate to promote formation of the biodegradable amide bond. Even though the parent antineoplastic ferrocene and phthalocyanine derivatives are themselves insoluble in water at pH < 7, the new carrier-drug conjugates that were obtained are well water-soluble. [ABSTRACT FROM AUTHOR]

Palladium-based heterometallic complexes are important because of their interesting physical properties and excellent catalytic activity. In this study, four monometallic trinuclear palladium long chain carboxylates and four palladium-based bimetallic bridging tetracarboxylate complexes were synthesised. These complexes were characterised by different techniques, including DSC, TGA-MS, X-Ray diffraction and IR spectroscopy. [ABSTRACT FROM AUTHOR]

Surface-hydroxylated silicon wafers, 8, were reacted with 3-aminopropyltrimethoxysilane, 9, to create wafers with amine-functionalized surfaces, 10. The metallocenylaldehydes FcCHO, 1 (Fc = ferrocenyl = FeII(C5H5)(C5H4)), RcCHO, 2 (Rc = ruthenocenyl = RuII(C5H5)(C5H4)), and OcCHO, 3 (Oc = osmocenyl = OsII(C5H5)(C5H4)) as well as the carboxylic acids FcCOOH, 4, RcCOOH, 5, OcCOOH, 6, and Cc+COOH·PF6 −, 7 (Cc+ = cationic cobaltocenium = [CoIII(C5H5)(C5H4)]+), were reacted with 10 to covalently anchor the metallocenes on the wafers either via an imine (–CH N–) or amide (–NHCO–) bond. The aldehydes were anchored more effectively than the carboxylic acids. Binding energies of all important atoms in all seven systems were determined by XPS measurements. Metal binding energies of the amide-bonded metallocenes were consistently larger (up to 0.6 eV) than those of the imine-anchored systems. AFM and SEM measurements showed that the covalently anchored metallocenes aggregate into nano-islets of diameter between 40 and 100 nm depending on the metallocene and type of anchoring bond. Up to seven additional layers of unreacted metallocenylaldehyde or -acid further stacked on top of the main layer of metallocene to form each islet. These additional layers of metallocene of each islet are stabilized by a large network of secondary and/or tertiary bonding forces. The main film surfaces have average thicknesses ranging between 2 and 6 nm, while film roughness, which is mostly associated with the islets, was with one exception (that of the Oc–CONH– surface 14) between 17% and 68% of the film thickness. The crystal structures for OcCHO, 3, and Cc+COOH·PF6 −, 7, was determined and the observed tertiary and secondary intermolecular interactions between independent molecules explains the formation of the nano-islets of each metallocene when anchored onto the aminated silicon wafers. [ABSTRACT FROM AUTHOR]

Biodegradable electronic devices play a crucial role in addressing the escalating issue of electronic waste accumulation, which poses significant environmental threats. In this study, we explore the utilization of a methanol-based extract of the Elaeodendron buchananii plant blended with a carboxymethyl cellulose biopolymer to produce a biodegradable and environmentally friendly functional material for a resistive switching memory system using silver and tungsten electrodes. Our analyses revealed that these two materials chemically interact to generate a perfect composite with near semiconducting optical bandgap (4.01 eV). The resultant device exhibits O-type memory behavior, with a low ON/OFF ratio, strong endurance (≥103 write/erase cycles), and satisfactory (≥103) data retention. Furthermore, through a comprehensive transport mechanism analysis, we observed the formation of traps in the composite that significantly improved conduction in the device. In addition, we established that altering the voltage amplitude modifies the concentration of traps, leading to voltage amplitude-driven multiple resistance states. Overall, our findings underscore the potential of functionalizing polymers that can be functionalized by incorporating plant extracts, resulting in biodegradable and nonvolatile memory devices with promising performance metrics.

Objective: To evaluate a model of care to improve arthritis detection and treatment in an urban Aboriginal population., Design: Cohort study., Setting: The Elbow River Healing Lodge in Calgary, Alta., Participants: A total of 26 participants with noninflammatory arthritis and 12 with inflammatory arthritis., Intervention: A monthly rheumatology clinic was embedded in the primary health care service and received referrals from primary care providers and allied health care professionals, or self-referrals. All participants had a standardized assessment to determine their diagnosis. Those with noninflammatory musculoskeletal conditions were returned to primary care management and those with inflammatory arthritis conditions were followed by the rheumatologist., Main Outcome Measures: Accessibility, acceptability, effectiveness, and cultural safety were evaluated as measures of quality for the model of care., Results: Nearly all participants (87%) thought the services were very easy or easy to obtain, and overall satisfaction with the model of care was high (89% were very satisfied or satisfied). For inflammatory arthritis patients, the swollen and tender joint counts improved over time (both P < .01) and patient safety was assured. A high degree of cultural safety was provided, with 95% of participants responding that they did not perceive discrimination on the basis of race., Conclusion: This model of care facilitated access for diagnosis and return to care of inflammatory arthritis conditions, and was acceptable to participants. This model of care removes the complexities of access to non-family physician specialty care while providing health care in a setting valued by Aboriginal patients., (Copyright© the College of Family Physicians of Canada.)

Background: Gold(I) and platinum(II) d(10) and d(8) electronic complexes such as (Au(PPh(2)CH(2)CH(2)PPh(2))(2))Cl and cisplatin, ((H(3)N)(2)PtCl(2)), possess strong antineoplastic activities. Almost no information is available regarding the anticancer activity of isoelectronic silver(I) d(10) complexes. This study examined the cytotoxicity of stable water-soluble silver(I) carboxylates. The results were related to the cytotoxicity of cisplatin and (Au(PPh(2)CH(2)CH(2)PPh(2))(2))Cl., Materials and Methods: The silver carboxylates (AgO(2)CCH(2)OCH(3)), 1, (AgO(2)C-CH(2)OCH(2)CH(2)OCH(3)), 2, and (AgO(2)CCH(2)OCH(2)CH(2)OCH(2)CH(2)OCH(3)), 3, were investigated. Cytotoxicity tests were performed on the HeLa (human cervix epitheloid) cancer cell line, resting lymphocytes and PHA (phytohaemagglutinin)-stimulated lymphocyte cultures. Cell survival was measured by means of the colorometric 3-(4,5-dimethylthiazol-2-yl)-diphenyltetrazolium bromide (MTT) assay., Results: The IC(50) (50% cell growth inhibition) values of 1-3 in the HeLa cells varied between 2.6 and 6.1 μmol dm(-3) with being 1 the most cytotoxic silver complex. Drug activity was inversely proportional to the length of the carboxylato chain length. Complexes 1-3 were 3-5 times more cytotoxic against the HeLa cancer cells than against the PHA stimulated lymphocyte cultures., Conclusion: A drug activity-structure relationship exists in that short-chain silver carboxylates are more cytotoxic than long-chain silver carboxylates, but silver d(10) complexes are one order of magnitude less cytotoxic than platinum(II) d(8) or gold(I) d(10) complexes.

Background: Ferrocene derivatives may possess antineoplastic activity. Those with low ferrocenyl reduction potentials often have the highest anticancer activity, as cell components have to oxidise them to the active ferrocenium species before cytotoxicity can be recorded. Some gold(I) complexes also possess anticancer activity. This study examined the cytotoxicity of ferrocenyl-ethynyl and ruthenocenyl-ethynyl complexes of gold and platinum. The results were related to the ease of iron oxidation in the ferrocenyl fragment and compared with the cytotoxicity of cisplatin, [(H(3)N)(2)PtCl(2)] and [Au(PPh(2)CH(2)CH(2)PPh(2))(2)]Cl., Materials and Methods: Ferrocene-containing gold and platinum complexes of the type Fc-C≡C-PPh(2), 1, and Fc-C≡C-PPh(2)→M with Fc=ferrocenyl (Fe(II)(η(5)-C(5)H(5)) (η(5)-C(5)H(4))), Ph=phenyl (C(6)H(5)) and M=Au-Cl, 2, Au-C≡C-Fc, 3, or Au-C≡C-Rc, 4 (Rc=ruthenocenyl, (Ru(II)(η(5)-C(5)H(5)) (η(5)-C(5)H(4))) and the complex [(Fc-C≡C-PPh(2))(2)PtCl(2)], 5, were investigated. Cytotoxicity tests were determined on the HeLa (human cervix epitheloid) cancer cell line, ATCC CCL-2. Cell survival was measured by means of the colorometric 3-(4,5-dimethylthiazol-2-yl)-diphenyltetrazolium bromide assay., Results: The IC(50) values of compounds 1-4 from four experiments causing 50% cell growth inhibition, ranged between 4.6 and 27 μmol dm(-3). Drug activity was inversely proportional to the sum of all formal reduction potentials, E(o'), of the ferrocenyl groups of the Fc-C≡C-PPh(2) and Fc-C≡C-ligands coordinated to the gold centre. The Fc-C≡C-PPh(2)→Au-Cl complex, compound 2, was most cytotoxic with IC(50)=4.6 μmol dm(-3) , demonstrating the beneficial effect the Cl(-) ion has on the cytotoxicity of these neutral gold complexes. The platinum complex [(Fc-C≡C-PPh(2))(2)PtCl(2)], compound 5, resembling the structure of cisplatin, in principle should exhibit good cytotoxicity, but was not tested due to its total insolubility in any biocompatible medium.