Small Interfering RNA–Mediated Suppression of Proislet Amyloid Polypeptide Expression Inhibits Islet Amyloid Formation and Enhances Survival of Human Islets in Culture

OBJECTIVE—Islet amyloid, formed by aggregation of the β-cell peptide islet amyloid polypeptide (IAPP; amylin), is a pathological characteristic of pancreatic islets in type 2 diabetes. Toxic IAPP aggregates likely contribute to the progressive loss of β-cells in this disease. We used cultured human islets as an ex vivo model of amyloid formation to investigate whether suppression of proIAPP expression would inhibit islet amyloid formation and enhance β-cell survival and function

In middle-aged and old obese patients, training intervention reduces leptin level: A meta-analysis

BACKGROUND: Leptin is one of the major adipokines in obesity that indicates the severity of fat accumulation. It is also an important etiological factor of consequent cardiometabolic and autoimmune disorders. Aging has been demonstrated to aggravate obesity and to induce leptin resistance and hyperleptinemia. Hyperleptinemia, on the other hand, may promote the development of age-related abnormalities. While major weight loss has been demonstrated to ameliorate hyperleptinemia, obese people show a poor tendency to achieve lasting success in this field. The question arises whether training intervention per se is able to reduce the level of this adipokine. OBJECTIVES: We aimed to review the literature on the effects of training intervention on peripheral leptin level in obesity during aging, in order to evaluate the independent efficacy of this method. In the studies that were included in our analysis, changes of adiponectin levels (when present) were also evaluated. DATA SOURCES: 3481 records were identified through searching of PubMed, Embase and Cochrane Library Database. Altogether 19 articles were suitable for analyses. STUDY ELIGIBILITY CRITERIA: Empirical research papers were eligible provided that they reported data of middle-aged or older (above 45 years of age) overweight or obese (body mass index above 25) individuals and included physical training intervention or at least fitness status of groups together with corresponding blood leptin values. STATISTICAL METHODS: We used random effect models in each of the meta-analyses calculating with the DerSimonian and Laird weighting methods. I-squared indicator and Q test were performed to assess heterogeneity. To assess publication bias Egger's test was applied. In case of significant publication bias, the Duval and Tweedie's trim and fill algorithm was used. RESULTS: Training intervention leads to a decrease in leptin level of middle-aged or older, overweight or obese male and female groups, even without major weight loss, indicated by unchanged serum adiponectin levels. Resistance training appears to be more efficient in reducing blood leptin level than aerobic training alone. CONCLUSIONS: Physical training, especially resistance training successfully reduces hyperleptinemia even without diet or major weight loss

Mechanical and fracture properties of sugar beetroot-based nanosheets (SNS) doped cementitious composites

This paper examines the mechanical and fracture properties of cementitious composites doped with a new type of 2D bio-nanoplatelets sheets, synthesized from sugar beet pulp waste. The sugar beetroot nanosheets (SNS) were added to the cement pastes at different concentrations. The influence of SNS treatment and water-to-cement (w/c) ratio on the performance of the cementitious composites was elucidated. The experimental results showed that 0.2- wt% and 0.35 were the optimal SNS concentration and w/c ratio for increasing the compressive, splitting tensile and flexural strength, flexural modulus, fracture energy and fracture toughness. These properties were enhanced by as much as 12.15%, 36.87%, 39.91%, 32.69%, 69.01% and 49.06%, respectively. This enhancement was due to crack deflection and crack bridging mechanisms in the cementitious composites as a result of the high specific surface area of SNS and the strong chemical and physical bonding of SNS with the hydration phases. The SNS materials offers strong advantages over graphene-based materials on improving the engineering properties of cementitious materials and reducing their cost and CO2 emissions

Effects of porosity on dynamic indentation resistance of silica nanofoam

Abstract The dynamic indentation behaviors of monolithic silica nanofoams of various porosities are investigated. When the pore size is on the nm scale, as the porosity increases, despite the decrease in mass density, the resistance offered by silica nanofoam to dynamic indentation is maintained at a high level, higher than the resistance of solid silica or regular porous silica. This phenomenon is related to the fast collapse of nanocells, which produces a locally hardened region and significantly increases the volume of material involved in impact energy dissipation