Hybrid composite rods subjected to excessive bending loads

Glass fiber/carbon fiber/epoxy hybrid composite rods were investigated in this research for their resistance to excessive bending. The rods are presently being used as the load bearing component of the Aluminum Conductor Composite Core/Trapezoidal Wire (ACCC/TW™) design. The ACCC/TW™ design is one of the most serious candidates to replace the existing conductor designs based on steel and aluminum wires. The effects of mandrel size and thickness of the insulating glass fiber composite sheath on the axial compressive stress state during bending of the ACCC rod were numerically investigated by performing non-linear finite element analyses of the conductor wrapping process. In addition, two sets of compression experiments were performed on composite specimens in order to determine the ultimate compressive strength of the ACCC rod and of the carbon fiber composite alone. During the compression tests, acoustic emissions were monitored from the specimens to determine if a different failure process exists for the hybrid composite as opposed to a traditional uni-directional long fiber composite. Proof tests, and subsequent Scanning Electron Microscope (SEM) work of each type of composite were also performed to better understand the failure process. It was clearly demonstrated in this research that ACCC rods will be mechanically damaged by excessive bending over small diameter mandrels used for transportation and installation purposes. This work should be of great help to the manufacturers and potential users of the ACCC conductors around the world.     

Measuring fig quality using near-infrared spectroscopy

Sorting of dried figs prior to inspection is labor-intensive and somewhat complex. We examined the potential of using near-infrared spectroscopy (NIRS) to automate sorting of dried figs. Calimyrna and Adriatic types were inspected by hand using established criteria. For both varieties, approximately 100 passable figs and 100 figs each for the infested, rotten, sour, and dirty defect categories were examined using NIRS and partial least-squares regression (PLS). Correct classifications for these varieties ranged from 83 to 100%. About twenty PLS factors were used to make the predictions. These results indicate that the use of NIRS to help automate inspection for dried fig processing is feasible. However, the large number of wavelengths needed for prediction, as indicated by PLS beta coefficients, indicates that implementing NIRS in fig sorting may require an instrument capable of reading numerous wavelengths rather than a more economical filter-based instrument.     

Ca2+ regulates calmodulin binding to IQ motifs in IRS-1

IRS-proteins couple the receptors for insulin and various cytokines to signalling proteins containing Src homology 2 (SH2) domains. Here we demonstrate that calmodulin, a mediator of Ca(2+)-dependent physiological processes, associates with IRS-1 in a phosphotyrosine-independent manner. IRS-1 coimmunoprecipitated with calmodulin from lysates of Chinese hamster ovary cells expressing IRS-1. The interaction was modulated by Ca2+, and calmodulin binding to IRS-1 was enhanced by increasing intracellular Ca2+ with A23187. In contrast, trifluoperazine, a cell-permeable calmodulin antagonist, decreased binding of calmodulin to IRS-1. Insulin stimulated tyrosine phosphorylation of IRS-1, but did not significantly alter the interaction between calmodulin and IRS-1. IQ-like motifs occur between residues 106-126 and 839-859 of IRS-1. Synthetic peptides based on the these sequences inhibited the association between IRS-1 and calmodulin. These data demonstrate that calmodulin binds to IRS-1 in intact cells in a Ca(2+)-regulated manner, providing a molecular link between the signalling pathways.     

Feeding deterrent compounds to the boll weevil,Anthonomus grandis Boheman in Rose-of-Sharon,Hibiscus syriacus L.

The Rose-of-Sharon,Hibiscus syriacus (L.), can be a significant alternate host plant for the boll weevil,Anthonomus gradis (Boh.). Boll weevils are known to be deterred from feeding and ovipositing in the buds unless the calyx is removed. This investigation was initiated to identify calyx allelochemicals that deter feeding with the eventual strategy of breeding for cotton lines high in these allelochemicals in the appropriate tissues. The feeding deterrency of calyx tissue from the buds of Rose-of-Sharon for the boll weevil was confirmed. The most active deterrent fraction was found to contain mostly fatty acids and their methyl esters. Saturated fatty acids and their methyl esters were generally found to be stimulatory, while the unsaturated species were found to be deterrent. Higher quantities of the fatty acids, particularly the unsaturated species, were found in Rose-of-Sharon calyx tissue than in the buds without calyx. This supports the hypothesis developed through the isolational work and testing of standards that the unsaturated fatty acids are significant deterrents of boll weevil feeding.Coleoptera: Curculionidae.Malvales: Malvaceae.Mention of a commercial or proprietary product in this paper does not constitute endorsement of this product by Delta State University or USDA.     

The effects of atmospheric aging on a hybrid polymer matrix composite

The effect of thermal exposure in an atmospheric environment for up to 1 year on the flexural performance, under both static and fatigue loading, of a glass fiber/carbon fiber hybrid polymer matrix composite material was evaluated. It was found that exposure to a temperature near, but below, the glass transition temperature resulted in diminished flexure strength as well as reduced fatigue performance. The magnitude of property reduction was, in general, proportional to the amount of aging time, and was found to be dictated by the dominant aging mechanism. Scanning electron microscopy revealed that the modest reduction in mechanical properties at intermediate aging times was predominantly attributed to thermal oxidation, while for longer aging times thermal aging (dimensional relaxation) was the primary cause for the substantial reduction. Dimensional relaxation of the composite was measured at several isothermal aging temperatures, from which, the activation energy of the aging process was determined. This work provides insight into the evolution of mechanical properties as a function of aging time in an atmospheric environment for a hybrid polymer matrix composite.     

Dapagliflozin Does Not Modulate Atherosclerosis in Mice with Insulin Resistance

Type 2 diabetes mellitus (T2DM) increases morbimortality in humans via enhanced susceptibility to cardiovascular disease (CVD). Sodium-glucose co-transporter 2 inhibitors (SGLT2i) are drugs designed for T2DM treatment to diminish hyperglycaemia by reducing up to 90% of renal tube glucose reabsorption. Clinical studies also suggest a beneficial action of SGLT2i in heart failure and CVD independent of its hypoglycaemiant effect. In the present study, we explored the effect of SGLT2i dapagliflozin (DAPA) in the metabolism and atherosclerosis in Apoe−/−Irs2+/− mice, which display accelerated atherosclerosis induced by insulin resistance. DAPA treatment of Apoe−/−Irs2+/− mice, which were fed a high-fat, high-cholesterol diet, failed to modify body weight, plasma glucose or lipid. Carbohydrate metabolism characterisation showed no effect of DAPA in the glucose tolerance test (GTT) despite augmented insulin levels during the test. In fact, decreased C-peptide levels in DAPA-treated mice during the GTT suggested impaired insulin release. Consistent with this, DAPA treatment of Apoe−/−Irs2+/− isolated islets displayed lower glucose-stimulated insulin secretion compared with vehicle-treated islets. Moreover, insulin-signalling experiments showed decreased pAKT activation in DAPA-treated adipose tissue indicating impaired insulin signalling in this tissue. No changes were seen in lesion size, vulnerability or content of macrophages, vascular smooth muscle cells, T cells or collagen. DAPA did not affect circulating inflammatory cells or cytokine levels. Hence, this study indicates that DAPA does not protect against atherosclerosis in insulin-resistant mice in hypercholesterolemic conditions.     

Biochemical and structural analysis of the IgE binding sites on ara h1, an abundant and highly allergenic peanut protein

Allergy to peanut is a significant IgE-mediated health problem because of the high prevalence, potential severity, and chronicity of the reaction. Ara h1, an abundant peanut protein, is recognized by serum IgE from >90% of peanut-sensitive individuals. It has been shown to belong to the vicilin family of seed storage proteins and to contain 23 linear IgE binding epitopes. In this communication, we have determined the critical amino acids within each of the IgE binding epitopes of Ara h1 that are important for immunoglobulin binding. Surprisingly, substitution of a single amino acid within each of the epitopes led to loss of IgE binding. In addition, hydrophobic residues appeared to be most critical for IgE binding. The position of each of the IgE binding epitopes on a homology-based molecular model of Ara h1 showed that they were clustered into two main regions, despite their more even distribution in the primary sequence. Finally, we have shown that Ara h1 forms a stable trimer by the use of a reproducible fluorescence assay. This information will be important in studies designed to reduce the risk of peanut-induced anaphylaxis by lowering the IgE binding capacity of the allergen.     

Food-associated gastrointestinal disease

The ingestion of food is frequently associated with specific adverse gastrointestinal symptoms, including emesis, diarrhea, abdominal cramping, and gastrointestinal bleeding. This brief review discusses a variety of food-induced gastrointestinal diseases and will highlight the recent information pertaining to the pathophysiology, clinical presentation, diagnostic approach, and treatment of these disorders. Reactions resulting from immediate hypersensitivity and cell-mediated processes will be reviewed in detail, as well as other proposed pathophysiologic mechanisms. The clinical presentation and diagnostic approach to several food-induced gastrointestinal diseases will be individually examined. In addition, the treatment, especially the proper use of nutritionally balanced restriction diets and hypoallergenic formulas, will be discussed.