Variants in the PPARGC1A Gene may Influence the Effect of Fat Intake on Resting Metabolic Rate in Obese Women

Recent studies have shown that dietary intake and genetic variants play a decisive role in the risk of obesity. Therefore, this study was designed to examine the interaction between dietary fat and PPARGC1A polymorphisms on the level of resting metabolic rate (RMR). We enrolled 288 Iranian overweight and obese women in this cross‐sectional study. We sequenced the 648 b.p. DNA in Exon 8 of PPARGC1A gene. We analyzed the two single‐nucleotide polymorphisms, namely rs11290186 and rs2970847, in this region. All participants were assessed for RMR, dietary intake, and body composition. This study demonstrated that total cholesterol and insulin levels were positively associated with T allele carriers of rs2970847. Moreover, the A‐deletion allele carrier of the rs11290186 genotype had higher triacylglycerol and insulin concentrations. The current study revealed that, after adjustment for energy intake, the AA genotype of PPARGC1A (rs11290186) had a direct association with polyunsaturated fatty acids and linoleic acid intakes. Another important finding in our study was that there was an interaction seen between fat and saturated fatty acids intake with the PPARGC1A genotypes. Women with fat intakes of more than 30% of calorie intake per day and the A‐deletion genotype had a lower RMR and RMR/fat free mass (FFM). It seems that the PPARGC1A polymorphisms lead to the downregulation of insulin signaling and subsequently insulin resistance. In addition, the interactions between the PPARGC1A polymorphisms (rs11290186) and the level of dietary fat intake probably can have an effect on RMR and RMR/FFM in obese women.     

Effects of shadowing on the number of active users in random multi-user channels

Prior work has addressed the effects of multipath fading and path loss separately for broadcast and multiple-access channels. It has been shown that the number of simultaneously active users are of the order \(\Theta (\ln (\ln (n)))\) for random channel gains with exponentially-decaying tails, where n is the total number of users. Furthermore, it has been shown that assuming path loss is dominant and ignoring multipath fading, the user capacity (i.e. the maximum number of simultaneously active users in a wireless system) of multi-user channels is of the order \(\Theta (\ln (n))\) when the users are spatially distributed on the plane with a Gaussian or Uniform distribution. In this paper, we study the shadowing effects on the number of active users for broadcast and multiple-access channels in which the users are randomly distributed on the plane. It is shown that as the total number of users in the multi-user channel goes to infinity, the number of active users is of the order \(\Theta (\sqrt{\ln (n)}).\)     

Medium chain length polyhydroxyalkanoates, promising new biomedical materials for the future

Medium chain length polyhydroxyalkanoates, mcl-PHAs (C₆-C₁₄ carbon atoms), are polyesters of hydroxyalkanoates produced mainly by fluorescent Pseudomonads under unbalanced growth conditions. These mcl-PHAs which can be produced using renewable resources are biocompatible, biodegradable and thermoprocessable. They have low crystallinity, low glass transition temperature, low tensile strength and high elongation to break, making them elastomeric polymers. Mcl-PHAs and their copolymers are suitable for a range of biomedical applications where flexible biomaterials are required, such as heart valves and other cardiovascular applications as well as matrices for controlled drug delivery. Mcl-PHAs are more structurally diverse than short chain length PHAs and hence can be more readily tailored for specific applications. Composites have also been fabricated using mcl-PHAs and their copolymers, such as poly (3-hydroxyoctanoate) [P(3HO)] combined with single walled carbon nanotubes and poly(3-hydroxbutyrate-co-3-hydroxyhexanoate) [P(3HB-co-3HHx)] combined with hydroxyapatite. Because of these attractive properties of biodegradability, biocompatibility and tailorability, Mcl-PHAs and their composites are being increasingly used for biomedical applications. However, studies remain limited mainly to P(3HO) and the copolymer P(3HB-co-3HHx), which are the only mcl-PHAs available in large quantities. In this review we have consolidated current knowledge on the properties and biomedical applications of these elastomeric mcl-PHAs, their copolymers and their composites.     

PLGA‐based in situ‐forming system: degradation behavior in the presence of hydroxyapatite nanoparticles

The degradation behavior of poly(lactic‐co‐glycolic acid) (PLGA) is important for its application as a biomaterial. In this work, the influence of nano‐hydroxyapatite (nano‐HA) on the degradation behavior of PLGA matrix was studied. PLGA‐based in situ forming system containing nano‐HA was prepared using the immersion precipitation method and the polymer hydrolysis was investigated in a phosphate buffer (pH 7.4) at 37°C. The pH values in the testing medium were evaluated to quantify the degradation process. Gel permeation chromatography and scanning electron microscopy techniques were employed to monitor changing of the weight‐average molecular weight (M_W) and the body structures of PLGA matrices, respectively. To model the M_W changes, a first‐order degradation model was employed. The formed PLGA matrices had different porosities that effected water penetration into the matrices following the hydrolysis process. The obtained degradation rate constant using a mathematical model for PLGA matrices with different nano‐HA content was about from 2.5 to 4.5 times lower than neat PLGA matrix. POLYM. ENG. SCI., 59:1028–1035, 2019. © 2019 Society of Plastics Engineers     

Preparation and In Vitro Evaluation of a New Fentanyl Patch Based on Acrylic/Silicone Pressure-Sensitive Adhesive Blends

In this study, the influence of the ratio of silicone (Si) to acrylic pressure-sensitive adhesive (PSA), polyvinyl pyrrolidone (PVP), and lauryl alcohol (LA)?%?(wt/wt) on the properties of a drug in adhesive patch containing 4%?(wt/wt) fentanyl as model drug was evaluated. The dependent variables selected were drug solubility, in vitro drug release in the platforms as well as adhesion properties including peel strength and tack value. By using the central composite design of Design Expert software, it was found that the effect of each factor was different, yet all had influenced dependent variables significantly (p?<?.05). Quadratic model generated for various response variables using backward regression analysis was found to be statistically significant (p?<?.05). It was deduced that the presence of PVP and Si displayed similar trends on drug solubility and release. Each role played by Si with LA and PVP in release rate was separately investigated, and it was found that the presence of PVP and LA in lowering the amount of drug released was more dominant compared with that of Si. The release patterns at the early and later stages follow the Higuchi and semiempirical models, respectively. Effect of PVP as well as Si and LA were similar on tack value. The influence of LA compared to peeling characteristics of Si system was more pronounced.     

Experimental study of convective heat transfer coefficient for pulsed fluidized bed using microcapsule phase change material

The convective heat transfer coefficient in a pulsating cylindrical fluidized bed using microcapsule particle-phase change material (MPCM) was examined experimentally. A solenoid on and off valve was used to provide the pulsation and was varied from 1 to 10 Hz. The test section in the bed was loaded with granular microparticle-phase change material (MPCM) with an average diameter of 200 µm. The pulsation effect on the thermal field, thermal storage, and heat transfer coefficient was investigated for 1.5, 2, and 2.5 of minimum fluidization velocity. Results indicated that the amplitude of the oscillation decreases with increasing in pulsation frequency. An increase in heat transfer rate was shown to be related to the superficial velocity. The maximum performance was obtained for the frequency of 7 Hz at the velocity ratio of 2.5. The convective heat transfer increased by 17% for frequency pulsation of 7 Hz. Furthermore, the Duty cycle (η) is defined as the ratio of turn-on duration to the total turn-on and off duration for entering airflow to the solenoid valve. It was shown that the η > 0.4 led to better mixing and higher heat transfer. However, the pulsation effect was shown to disappear for the duty cycle of higher than 0.8. Comparison with the available experimental data of others for continuous flow was in good agreement.