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In this study, we examined chronic norepinephrine suppression of insulin secretion in sheep fetuses with placental insufficiency-induced intrauterine growth restriction (IUGR). Glucose-stimulated insulin secretion (GSIS) was measured with a square-wave hyperglycemic clamp in the presence or absence of adrenergic receptor antagonists phentolamine ([alpha]) and propranolol ([beta]). IUGR fetuses were hypoglycemic and hypoxemic and had lower GSIS responsiveness (P [less than or equal to] 0.05) than control fetuses. IUGR fetuses also had elevated plasma norepinephrine (3,264 [+ or -] 614 vs. 570 [+ or -] 86 pg/ml; P [less than or equal to] 0.05) and epinephrine (164 [+ or -] 32 vs. 60 [+ or -] 12 pg/ml; P [less than or equal to] 0.05) concentrations. In control fetuses, adrenergic inhibition increased baseline plasma insulin concentrations (1.7-fold, P [less than or equal to] 0.05), whereas during hyperglycemia insulin was not different. A greater (P [less than or equal to] 0.05) response to adrenergic inhibition was found in IUGR fetuses, and the average plasma insulin concentrations increased 4.9-fold at baseline and 7.1-fold with hyperglycemia. Unlike controls, basal plasma glucose concentrations fell (P [less than or equal to] 0.05) with adrenergic antagonists. GSIS responsiveness, measured by the change in insulin, was higher (8.9-fold, P [less than or equal to] 0.05) in IUGR fetuses with adrenergic inhibition than controls (1.8-fold, not significant), showing that norepinephrine suppresses insulin secretion in IUGR fetuses. Strikingly, in IUGR fetuses, adrenergic inhibition resulted in a greater GSIS responsiveness, because [beta]-cell mass was 56% lower and the maximal stimulatory insulin response tended (P < 0.1) to be higher than controls. This persistent norepinephrine suppression appears to be partially explained by higher mRNA concentrations of adrenergic receptors [[alpha].sub.1D], [[alpha].sub.2A], and [[alpha].sub.2B] in a cohort of fetuses that were naive to the antagonists. Therefore, norepinephrine suppression of insulin secretion was maintained, in part, by upregulating adrenergic receptor expression, but the [beta]-cells also appeared to compensate with enhanced GSIS. These findings may begin to explain why IUGR infants have a propensity for increased glucose requirements if norepinephrine is suddenly decreased after birth. pancreas; islets of Langerhans; hypoxia; glucose-stimulated insulin secretion; fetal growth restriction doi: 10.1152/ajpendo.00494.2009.

Sodium/potassium-ion batteries (SIBs/PIBs) are expected to replace conventional lithium-ion batteries (LIBs) soon in view of their lower cost and the abundant reserves of sodium/potassium resources. However, it remains a challenge to explore suitable anode materials for SIBs/PIBs with high energy/power density and long lifespan due to the sluggish kinetics during the insertion/extraction of Na+/K+ ions with larger ionic sizes. Herein, ultra-small SnS2 nanocrystals encapsulated in sulphurized polyacrylonitrile (SPAN) fibres have been fabricated via electrospinning paired with sulphuration treatment. Density functional theory (DFT) calculations demonstrate that SPAN fibre can concentrate Na+ on the surface and offer additional storage sites with enhanced reaction kinetics. Consequently, this composite electrode manifests superb sodium/potassium-ion storage performance with high capacities (613 mA h g−1 after 50 cycles under 0.1 A g−1 for SIBs; 565 mA h g−1 at 0.05 A g−1 and 226 mA h g−1 at 5 A g−1 after 50 and 2000 cycles for PIBs) and superior long-life cycling capability (261 mA h g−1 after 30 000 cycles at 10 A g−1 for SIBs). Additionally, a sodium full cell assembled with Na3V2(PO4)3 as the cathode and SnS2-SPAN-470-1 as the anode displays excellent cycling performance. This work can provide new insights into the construction of novel transition metal dichalcogenide-based nanostructures and nanocomposites for high-performance electrochemical energy storage and conversion devices. [ABSTRACT FROM AUTHOR]

In order to study the variation of the drafting force of cotton slivers, a three-dimensional model of cotton slivers was proposed. The model is based on the three-dimensional network structure of the fibers in the cotton sliver. The three-dimensional network structure is simulated by an octahedron. Based on the similarity between dynamic drawing and static drawing, the static drawing simulation of the model is carried out by using ANSYS software, and the static drawing force of different quantitative cotton slivers is simulated. The results show that the average relative error of the static stretch force and dynamic drafting force is 8.09%, and the maximum relative error is less than 15%. Then, the equations of the dynamic drafting force and static stretch force are obtained by linear regression, and the drawing force under other quantitative conditions is successfully predicted. Finally, static stretching is used to simulate the influence curve of different roller spacings on the dynamic drafting force, and the results show that the simulation results are consistent with the actual situation. Therefore, the octahedral cotton sliver model is effective, and the simulation results also provide a reference for the approximate prediction of dynamic drafting force. [ABSTRACT FROM AUTHOR]

A flexible approach to both type II and III lepadin alkaloids is developed for the first time. A key Diels–Alder reaction based on a novel chiral ketolactone dienophile is employed to obtain the desirable all- cis -trisubstituted cyclohexene with excellent regio- and stereoselectivity. As the subsequent closure of the piperidine ring is devised at the N1 and C2 position via an intramolecular nucleophilic amination, the two stereochemical types of lepadin frameworks with the opposite configuration at C2 can be conveniently accessible from a common intermediate. By the approach, lepadins D, E (type II) and F (type III) are stereo-selectively synthesized from ethyl l -lactate. [ABSTRACT FROM AUTHOR]

Herein, we report the first synthesis of colloidal C4N quantum dots (QDs) and their functional composites and explore their optical activities and edge‐selective polysulfide adsorption‐catalysis. As‐obtained C4NQDs are rich in carbonyl groups and edges, allowing good solution processability and facile assembly with other moieties for creating functionalities. While C4NQDs show normal fluorescence (FL), the QD/poly(vinyl alcohol) (PVA) composites give FL/room‐temperature‐phosphorescence (RTP) dual‐mode emission, enabling the corresponding solution to be used as an encryption ink. The QDs anchored onto carbon nanotubes can be used as a barrier layer to decorate commercial separators, endowing a Li−S cell with excellent cycling stability, high rate capability, and large areal capacity. Computation and experiment studies show that edge sites in C4N favor polysulfide adsorption and catalysis and the enriched edges and carbonyl groups in QDs synergically promotecatalytic conversion of sulfur species. [ABSTRACT FROM AUTHOR]

Reciprocal translocation and Robertsonian translocation are known to be causative factors of male infertility. However, the association between autosomal reciprocal translocation, Robertsonian translocation and semen parameters remains controversial. We performed a retrospective study and systematic review to investigate semen parameters in patients with autosomal reciprocal translocation or Robertsonian translocation. We recruited a total of 1,033 controls, 723 reciprocal translocation carriers and 326 Robertsonian translocation carriers. Men in the control, reciprocal translocation and Robertsonian translocation groups had a median age of 32.0 (95% CI, 32.0–33.0), 32.0 (95% CI, 32.0–33.0) and 33.0 (95% CI, 32.0–33.0) years respectively. Results showed that sperm concentration, total number per ejaculate, total motility, progressive motility of autosomal reciprocal translocation and Robertsonian translocation carriers were statistically lower than controls (p <.001). Eleven studies featuring 794 patients were enrolled in this systematic review. Compared with controls, autosomal reciprocal translocation and Robertsonian translocation carriers showed lower sperm concentration, total motility, progressive motility and normal morphology. Our results support the conclusion that sperm concentration, total number per ejaculate, total motility and progressive motility are significantly lower in autosomal reciprocal translocation and Robertsonian translocation carriers than in controls. [ABSTRACT FROM AUTHOR]