Trace elements in glucometabolic disorders: an update

Many trace elements, among which metals, are indispensable for proper functioning of a myriad of biochemical reactions, more particularly as enzyme cofactors. This is particularly true for the vast set of processes involved in regulation of glucose homeostasis, being it in glucose metabolism itself or in hormonal control, especially insulin. The role and importance of trace elements such as chromium, zinc, selenium, lithium and vanadium are much less evident and subjected to chronic debate. This review updates our actual knowledge concerning these five trace elements. A careful survey of the literature shows that while theoretical postulates from some key roles of these elements had led to real hopes for therapy of insulin resistance and diabetes, the limited experience based on available data indicates that beneficial effects and use of most of them are subjected to caution, given the narrow window between safe and unsafe doses. Clear therapeutic benefit in these pathologies is presently doubtful but some data indicate that these metals may have a clinical interest in patients presenting deficiencies in individual metal levels. The same holds true for an association of some trace elements such as chromium or zinc with oral antidiabetics. However, this area is essentially unexplored in adequate clinical trials, which are worth being performed

Influence of hybrid nano-filler on the crystallization behaviour and interfacial interaction in polyamide 6 based hybrid nano-composites

Expanded graphite (EG) and multiwalled carbon nanotubes (MWNTs) based hybrid nano-composites were prepared with polyamide 6 (PA6) matrix via melt-mixing technique using a conical twin-screw micro-compounder. A novel organic modifier (lithium salt of 6-aminohexanoic acid; Li-AHA) was employed to modify MWNTs, which was utilized to intercalate Li-AHA modified MWNTs into the partially exfoliated EG gallery. Morphological investigation showed the intercalation of Li-AHA modified MWNTs into a partially exfoliated EG gallery in an EG/MWNTs-m2h hybrid, whereas the unmodified EG/MWNTs-h hybrid mixture exhibited a separate identity in the mixture. Improved interaction via melt-interfacial reaction between the acid end group of PA6 and the amine functionality of Li-AHA in the EG/MWNTs-m2h hybrid filler was confirmed by Fourier transform infrared spectroscopic analysis. The extent of melt-interfacial reaction was increased as a function of Li-AHA concentration in the filler. Wide angle X-ray diffraction analysis showed the existence of the alpha-crystalline phase of PA6. The incorporation of MWNTs, EG and EG/MWNTs hybrid in the PA6 matrix has favoured an alpha-crystalline structure of the PA6 phase. Crystallization studies have indicated a significant increase in the bulk crystallization temperature of the PA6 phase in the presence of MWNTs, EG and the EG/MWNTs hybrid filler. Moreover, the formation of PA6 'trans-crystalline lamellae' on the MWNTs surface was facilitated in the case of composites with MWNTs and the EG/MWNTs hybrid filler. An attempt has been made to investigate the role of the EG/MWNTs hybrid filler in influencing the crystallization behaviour of the PA6 phase in the hybrid nano-composites

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Not AvailableSelection of gastropod shells as shelter by hermit crabs in controlled experiments would provide useful information on the utility of these shells in nature. In this study, shell size and species preferences of Diogenes alias from the northeastern Arabian Sea were quantified by free choice experiments. Males of D. alias, prefer Indothais lacera and Tibia curta, when choice was given; no differences were found for other demographic groups. All hermit crabs occupied larger shells than the shells they occupied in nature. The best correlation was observed between internal volume, weight, and aperture width of the shell with the size of the hermit crab. This pattern has also been reported for other species (i.e., Clibanarius albidigitus, Calcinus tibicen, and C. obscurus). Furthermore, the present study highlights the importance of optimal resources in a scarce environment.Not Availabl

Optimal short-term reservoir operation with integrated long-term goals

A methodology to incorporate long-term goals within the short-term reservoir operation optimization model is proposed. Two conflicting objectives for the management of hydropower generation in two different power plants are incorporated. A chance-constrained optimization model is used to derive long-term (annual) operation strategies. With the time horizon of operation for the short-term optimization model kept equal to a single time-step of the long-term optimization model, the optimum end storages derived from the long-term model are incorporated as constraints (storage lower bounds) within the short-term model. The long-term benefits accrued from such an operation model are illustrated for a small reservoir, in South India. The solutions are compared with the historic operation. These are also compared with the solutions of a short-term optimal operation model ignoring long-term goals. The optimization model is solved using a multi-objective genetic algorithm

Co-Processed Excipients for Dispersible Tablets–Part 1: Manufacturability

Co-processed excipients may enhance functionality and reduce drawbacks of traditional excipients for the manufacture of tablets on a commercial scale. The following study aimed to characterise a range of co-processed excipients that may prove suitable for dispersible tablet formulations prepared by direct compression. Co-processed excipients were lubricated and compressed into 10.5-mm convex tablets using a Phoenix compaction simulator. Compression profiles were generated by varying the compression force applied to the formulation and the prepared tablets were characterised for hardness, friability, disintegration and fineness of dispersion. Our data indicates that CombiLac, F-Melt type C and SmartEx QD100 were the top 3 most suitable out of 16 co-processed excipients under the conditions evaluated. They exhibited good flow properties (Carr’s index ˂ 20), excellent tabletability (tensile strength > 3.0 MPa at 0.85 solid fraction), very low friability (< 1% after 15 min), rapid disintegration times (27–49 s) and produced dispersions of ideal fineness (< 250 μm). Other co-processed excipients (including F-Melt type M, Ludiflash, MicroceLac, Pharmaburst 500 and Avicel HFE-102) may be appropriate for dispersible tablets produced by direct compression providing the identified disintegration and dispersion risks were mitigated prior to commercialisation. This indicates that robust dispersible tablets which disintegrate rapidly could be manufactured from a range of co-processed excipients