An innovative approach to fabricate a thermosensitive melatonin-loaded conductive pluronic/chitosan hydrogel for myocardial tissue engineering

This study aimed at designing and fabrication of a novel injectable and thermosensitive melatonin-loaded pluronic/chitosan hydrogel containing gold nanoparticles (GNPs) and poly glycerol sebacate (PGS) for myocardial tissue engineering. The PGS nanoparticles were used as the melatonin (drug model) carrier. The gelation time, syringeability, stability, and swelling of the hydrogel were scrutinized. Rheological properties, chemical composition, and morphology of the samples were also investigated. The effect of GNPs addition on the electrical conductivity of hydrogel was assessed. The cytotoxicity of hydrogels was assessed through MTT assay in the exposure of H9C2 cells up to 7 days. Scanning electron microscopy was applied to evaluate the morphology of seeded cells. The synthesis parameters of PGS nanoparticles were optimized through which 2.5%w/v of PGS and 1:10 organic phase to aqueous phase (O/A) ratio were found desirable. The optimum hydrogel illustrated 2 min gelation time and was stable up to 20 days with 5% swelling in the first 12 h into phosphate buffered saline. The GNPs with a uniform distribution rendered the hydrogel electrically conductive (1500 μS/cm). According to the MTT assay results, 3.125 μM melatonin was considered as the suitable concentration by which a significant increase in the cell viability was observed. The results exhibited that the prepared hydrogel composed of pluronic/chitosan/GNPs, and 3.125 μM melatonin-loaded PGS nanoparticles could be applied as a promising scaffold for myocardial tissue engineering.     

Elevation of blood β-hydroxybutyrate concentration affects glucose metabolism in dairy cows before and after parturition

Recent studies in mid- and late-lactation dairy cows showed that β-hydroxybutyrate (BHB) infusion had a considerable effect on glucose metabolism and immune response during intramammary lipopolysaccharide challenge. The objective of the present study was to infuse BHB during the dry period and after parturition to investigate the effects of elevated plasma BHB concentrations on metabolism and endocrine changes in transition dairy cows. The hypothesis tested was that regulation of glucose metabolism would change at different physiological stages and an additional elevation of BHB concentration would alter glucose concentration. Multiparous Holstein cows in wk ?2 (antepartum, a.p.; n = 6) and wk +2 (postpartum, p.p.; n = 8) relative to calving were infused (4 h from 0800 to 1200 h) with a BHB solution to increase plasma BHB concentration to 1.5 to 2.0 mmol/L (HyperB). The same period the next day without any infusion was considered the control period (CON). Blood samples were taken 1 h before the start of infusion as reference samples and every 30 min during the following 6 h (4 h of infusion and 2 h after infusion) in the HyperB and CON periods, and analyzed for glucose, BHB, insulin, and glucagon concentrations. During the steady state period (the latter 2 h of the 4-h infusion), plasma BHB concentration reached 1.87 ± 0.05 mmol/L (a.p.) and 1.93 ± 0.05 mmol/L (p.p.) in HyperB compared with 0.55 ± 0.06 mmol/L (a.p.) and 0.64 ± 0.04 mmol/L (p.p.) in CON, respectively. The 4-h average BHB infusion rate was 12.4 ± 1.0 and 13.3 ± 0.9 μmol/kg of BW per minute in wk ?2 and +2, respectively. Infusion of BHB caused a decrease of plasma glucose concentrations relative to preinfusion levels both before and after parturition, although basal glucose concentrations were different before and after calving. Infusion of BHB increased plasma insulin concentrations a.p. but not p.p., despite a higher basal insulin concentration before than after parturition. These findings show that effects of hyperketonemia on plasma glucose concentrations are similar before and after calving but that endocrine adaptation to hyperketonemia differs before and after parturition. We assume that BHB is a metabolic key regulator in early lactating dairy cows and may affect glucose concentration by further pathways such as gluconeogenesis and altered lipolysis.     

Biopolymer Nanovehicles for Oral Delivery of Natural Anticancer Agents

Cancer is the second leading cause of death throughout the world. Nature-inspired anticancer agents (NAAs) that are a gift of nature to humanity have been extensively utilized in the alleviation/prevention of the disease due to their numerous pharmacological activities. While the oral route is an ideal and common way of drug administration, the application of NAAs through the oral pathway has been extremely limited owing to their inherent features, e.g., poor solubility, gastrointestinal (GI) instability, and low bioavailability. With the development of nano-driven encapsulation strategies, polymeric vehicles, especially those with natural origins, have demonstrated a potent platform, which can professionally shield versatile NAAs against GI barricades and safely deliver them to the site of action. In this review, the predicament of orally delivering NAAs and the encapsulation strategy solutions based on biopolymer matrices are summarized. Proof-of-concept in vitro/in vivo results are also discussed for oral delivery of these agents by various biopolymer vehicles, which can be found so far from the literature. Last but not the least, the challenges and new opportunities in the field are highlighted.     

Structural optimization of four designed roof modules: Inspired by Voronax grid shell structures

Architects have been following nature in their constructions for a long time. Observations of nature reveal that it has many highly developed structures that provide scientists and engineers with a lot of useful clues for creating more efficient structures and building forms. Therefore, revealing systematic thinking about natural species is a crucial requirement for today’s buildings. A software analysis method was used to design four modules in the roof structure of the Iranian University of Science and Technology’s exhibition. The roof structure is based on the Voronax structure, which is a relaxed formof Voronoi, which is seen in the structures ofmany natural creatures. They were analyzed in terms of optimization and structural simulation using Grass-hopper plugins and tools by taking into account VonMises stress in the structural design. The results indicated that by increasing the density of Voronax cells in the areaswith high Von Mises stress concentration, a more efficient structure could be achieved in terms of load-bearing and designing predefined free-form roof structures. By analyzing predefined roof structures in an optimum way, the study took a step toward optimizing these kinds of structures.     

Protein detection through different platforms of immuno-loop-mediated isothermal amplification

Different immunoassay-based methods have been devised to detect protein targets. These methods have some challenges that make them inefficient for assaying ultra-low-amounted proteins. ELISA, iPCR, iRCA, and iNASBA are the common immunoassay-based methods of protein detection, each of which has specific and common technical challenges making it necessary to introduce a novel method in order to avoid their problems for detection of target proteins. Here we propose a new method nominated as ‘immuno-loop-mediated isothermal amplification’ or ‘iLAMP’. This new method is free from the problems of the previous methods and has significant advantages over them. In this paper we also offer various configurations in order to improve the applicability of this method in real-world sample analyses. Important potential applications of this method are stated as well.     

Signal promoting role of a p-type transition metal dichalcogenide used for the detection of ultra-trace amounts of diclofenac via a labeled aptasensor

A p-type transition metal dichalcogenide (WS₂) was synthesized and hybridized with graphene oxide via a simple hydrothermal method. The as-prepared material was used to modify a glassy carbon electrode for the fabrication of a simple, stable, and repeatable methylene blue-labeled “signal-off” aptasensor used for the sensitive determination of very low amounts of sodium diclofenac (DCF). The synthetic material, modification process, and role of WS₂ in the current response enhancement were studied by X-ray diffraction, energy-dispersive X-ray spectroscopy, field emission scanning electron microscopy, high resolution transmission electron microscopy, Hall effect, cyclic voltammetry, differential pulse voltammetry, and electrochemical impedance spectroscopy. Subsequently, a wide linear range of DCF concentration (0.5–300 nmol/L), very low limit of detection (0.23 nmol/L), and good selectivity were obtained using the differential pulse voltammetry method with the assembled aptasensor. Finally, the fabricated aptasensor was successfully developed for physiological real samples with significant recoveries.     

Microwave ferrites, part 1: fundamental properties

Ferrimagnets having low RF loss are used in passive microwave components such as isolators, circulators, phase shifters, and miniature antennas operating in a wide range of frequencies (1–100 GHz) and as magnetic recording media owing to their novel physical properties. Frequency tuning of these components has so far been obtained by external magnetic fields provided by a permanent magnet or by passing current through coils. However, for high frequency operation the permanent part of magnetic bias should be as high as possible, which requires large permanent magnets resulting in relatively large size and high cost microwave passive components. A promising approach to circumvent this problem is to use hexaferrites, such as BaFe₁₂O₁₉ and SrFe₁₂O₁₉, which have high effective internal magnetic anisotropy that also contributes to the permanent bias. Such a self-biased material remains magnetized even after removing the external applied magnetic field, and thus, may not even require an external permanent magnet. In garnet and spinel ferrites, such as Y₃Fe₅O₁₂ (YIG) and MgFe₂O₄, however, the uniaxial anisotropy is much smaller, and one would need to apply huge magnetic fields to achieve such high frequencies. In Part 1 of this review of microwave ferrites a brief discussion of fundamentals of magnetism, particularly ferrimagnetism, and chemical, structural, and magnetic properties of ferrites of interest as they pertain to net magnetization, especially to self biasing, are presented. Operational principles of microwave passive components and electrical tuning of magnetization using magnetoelectric coupling are discussed in Part 2.     

The effects of psyllium supplementation on body weight,body mass index and waist circumference in adults: A systematic review and dose-response meta-analysis of randomized controlled trials

Abstract

Background: Previous studies reported inconsistent findings regarding the effects of psyllium supplementation on obesity measures. This systematic review and meta-analysis was performed to summarize data from available randomized clinical trials (RCTs) on the effect of psyllium supplementation on body weight, body mass index (BMI), and waist circumference (WC) in adults.

Methods: PubMed, SCOPUS, Cochrane Library, and Google Scholar were searched to identify relevant articles up to August 2018. The effect sizes were presented as weighted mean difference (WMD) and 95% confidence intervals (CI) by using random effects model. To detect dose-response relationships, we used fractional polynomial modeling.

Results: A total of 22 RCTs were included. Meta-analysis did not find any significant effect of psyllium supplementation on body weight (MD: ?0.28?kg, 95% CI: ?0.78, 0.21, p?=?0.268), BMI (MD: ?0.19?kg/m², 95% CI: ?0.55, 0.15, p?=?0.27) and WC (MD: ?1.2?cm, 95% CI: ?2.6, 0.2, p?=?0.09). Subgroup analysis showed that psyllium dosage, kind of psyllium administration, duration of trial, study design, sample size, and gender were potential sources of heterogeneity. Moreover, there was nonlinear association between duration of psyllium consumption, BMI and WC.

Conclusion: Psyllium supplementation does not reduce body weight, BMI, and WC significantly.     

Free‐Standing Functionalized Graphene Oxide Solid Electrolytes in Electrochemical Gas Sensors

A free‐standing sulfonic acid functionalized graphene oxide (fSGO)‐based electrolyte film is prepared and used in an electrochemical gas sensor, an alcohol fuel cell sensor (AFCS), for the detection of alcohol. The fSGO electrolyte film‐based AFCS detects ethanol vapor with excellent response, linearity, and sensitivity, since it possesses a high proton conductivity (58 mS cm^?1 at 55 °C). An ethanol detection limit level as low as 25 ppm is achieved and high selectivity for ethanol over acetone is demonstrated. These results do not only show the promising potential of fSGO films in an electrochemical gas sensors, specifically a portable breathalyzer, but also open an alternative pathway to investigate the application of graphene derivatives in the field of gas sensors.     

Analytical investigation of surface potential and related properties of metal/insulator/III–V semiconductor capacitors

An analytical study of the effect of an applied gate bias on the potential and electron density in the semiconductor of metal/insulator/III–V semiconductor (III–V MIS) capacitors is carried out. For this, Poisson's equation is rewritten to a form amenable to analytical study. Si₃N₄ is used as an insulator layer for the MIS capacitors. In order to highlight the advantages of III–V MIS capacitors over metal-SiO₂---Si (MOS) capacitors, the ideal case free from interface traps is considered and theoretical results are obtained also for MOS capacitors. The calculated results strongly demonstrate the superiority of InGaAs MIS and GaAs MIS capacitors to Si MOS capacitors and pinpoint the situation in which the interface states are present.