Investigation of Photophysical and Electrochemical Properties of Magic-Sized CdS Nanocrystals

poster abstractColloidal semiconductor nanocrystals (NCs) have been the interest of many studies over the past two decades due to their applications in device fabrication, electrocatalysts, and medical diagnostics. Recent discovery of thermodynamically stable ultra-small nanocrystals (“magic-sized”) has provided the opportunity to understand their different properties at the molecular level. Herein we present the synthesis and purification of poly(ethylene glycol) thiolate-capped magic-sized CdS nanocrystals with distinct photophysical properties. These CdS NCs overcame solubility restraints by directly transferring from aqueous to organic mediums and also showed significant increased in peak sharpness when analyzed by high-resolution MALDI-TOF-MS, which confirmed formation of (CdS)33,34 nanocrystals. The electrochemical properties of dissolved CdS nanocrystals were investigated in organic solvent/electrolyte medium by different voltammetric techniques. The nanocrystals displayed molecule-like HOMO-LUMO energy gap. The electrochemical features are strongly temperature, solvent, and capping-ligand thickness dependent. We also developed a working model of the energy level structure of the PEG-thiolate-capped (CdS)33,34 nanocrystals

Amide Synthesis through the In Situ Generation of Chloro- and Imido-Phosphonium Salts

We describe a methodology for the amidation of carboxylic acids by generating phosphonium salts in situ from N-chlorophthalimide and triphenylphosphine. Aliphatic, benzylic, and aromatic carboxylic acids can be transformed into their amide counter parts using primary and secondary amines. This functional group interconversion is achieved at room temperature in good to excellent yields. Mechanistic work shows the in situ formation of chloro- and imido-phosphonium salts that react as activating agents for carboxylic acids and generate an acyloxy-phosphonium species

Health services under pressure: a scoping review and development of a taxonomy of adaptive strategies

Objective The objective of this review was to develop a taxonomy of pressures experienced by health services and an accompanying taxonomy of strategies for adapting in response to these pressures. The taxonomies were developed from a review of observational studies directly assessing care delivered in a variety of clinical environments. Design In the first phase, a scoping review of the relevant literature was conducted. In the second phase, pressures and strategies were systematically coded from the included papers, and categorised. Data sources Electronic databases (MEDLINE, Embase, CINAHL, PsycInfo and Scopus) and reference lists from recent reviews of the resilient healthcare literature. Eligibility criteria Studies were included from the resilient healthcare literature, which used descriptive methodologies to directly assess a clinical environment. The studies were required to contain strategies for managing under pressure. Results 5402 potential articles were identified with 17 papers meeting the inclusion criteria. The principal source of pressure described in the studies was the demand for care exceeding capacity (ie, the resources available), which in turn led to difficult working conditions and problems with system functioning. Strategies for responding to pressures were categorised into anticipatory and on-the-day adaptations. Anticipatory strategies included strategies for increasing resources, controlling demand and plans for managing the workload (efficiency strategies, forward planning, monitoring and co-ordination strategies and staff support initiatives). On-the-day adaptations were categorised into: flexing the use of existing resources, prioritising demand and adapting ways of working (leadership, teamwork and communication strategies). Conclusions The review has culminated in an empirically based taxonomy of pressures and an accompanying taxonomy of strategies for adapting in response to these pressures. The taxonomies could help clinicians and managers to optimise how they respond to pressures and may be used as the basis for training programmes and future research evaluating the impact of different strategies

Carelessly / music by Norman Ellis; words by Charles Kenny

Cover: photo of Red Nichols; Publisher: Irving Berlin Inc. (New York)https://egrove.olemiss.edu/sharris_e/1040/thumbnail.jp

The P450 CYP6Z1 confers carbamate/pyrethroid cross-resistance in a major African malaria vector beside a novel carbamate-insensitive N485I acetylcholinesterase-1 mutation

Carbamates are increasingly used for vector control notably in areas with pyrethroid resistance. However, a cross-resistance between these insecticides in major malaria vectors such as Anopheles funestus could severely limit available resistance management options. Unfortunately, the molecular basis of such cross-resistance remains uncharacterized in An. funestus, preventing effective resistance management. Here, using a genome-wide transcription profiling, we revealed that metabolic resistance through up-regulation of cytochrome P450 genes is driving carbamate resistance. The P450s CYP6P9a, CYP6P9b and CYP6Z1 were the most up-regulated detoxification genes in the multiple resistant mosquitoes. However, in silico docking simulations predicted CYP6Z1 to metabolise both pyrethroids and carbamates, whereas CYP6P9a and CYP6P9b were predicted to metabolise only the pyrethroids. Using recombinant enzyme metabolism and inhibition assays we demonstrated that CYP6Z1 metabolizes bendiocarb and pyrethroids, whereas CYP6P9a and CYP6P9b metabolise only the pyrethroids. Other up-regulated gene families in resistant mosquitoes included several cuticular protein genes suggesting a possible reduced penetration resistance mechanism. Investigation of the target-site resistance in acetylcholinesterase 1 (ace-1) gene detected and established the association between the new N485I mutation and bendiocarb resistance (Odds ratio 7.3; P<0.0001). The detection of multiple haplotypes in single mosquitoes after cloning suggested the duplication of ace-1. A TaqMan genotyping of the N485I in nine countries revealed that the mutation is located only in Southern Africa with frequency of 10-15% suggesting its recent occurrence. These findings will help in monitoring the spread and evolution of carbamate resistance and improve the design of effective resistance management strategies to control this malaria vector