Review: the latest advances in biomedical applications of chitosan hydrogel as a powerful natural structure with eye-catching biological properties

Journal of Materials Science - Chitosan is one of the natural cationic polymers with unique properties such as non-toxicity, biodegradability, biocompatibility, environmentally friendly that has...     

Bovidae-based gelatin: Extractions method,physicochemical and functional properties,applications, and future trends

Gelatin is one of the most important multifunctional biopolymers and is widely used as an essential ingredient in food, pharmaceutical, and cosmetics. Porcine gelatin is regarded as the leading source of gelatin globally then followed by bovine gelatin. Porcine sources are favored over other sources since they are less expensive. However, porcine gelatin is religiously prohibited to be consumed by Muslims and the Jewish community. It is predicted that the global demand for gelatin will increase significantly in the future. Therefore, a sustainable source of gelatin with efficient production and free of disease transmission must be developed. The highest quality of Bovidae-based gelatin (BG) was acquired through alkaline pretreatment, which displayed excellent physicochemical and rheological properties. The utilization of mammalian- and plant-based enzyme significantly increased the gelatin yield. The emulsifying and foaming properties of BG also showed good stability when incorporated into food and pharmaceutical products. Manipulation of extraction conditions has enabled the development of custom-made gelatin with desired properties. This review highlighted the various modifications of extraction and processing methods to improve the physicochemical and functional properties of Bovidae-based gelatin. An in-depth analysis of the crucial stage of collagen breakdown is also discussed, which involved acid, alkaline, and enzyme pretreatment, respectively. In addition, the unique characteristics and primary qualities of BG including protein content, amphoteric property, gel strength, emulsifying and viscosity properties, and foaming ability were presented. Finally, the applications and prospects of BG as the preferred gelatin source globally were outlined.     

A Quest for (sila)0-4cyclopentasilylenes and their Arduengo Analogs by DFT

Silicon - Following our interest in exotic silylenes, here we compare and contrast 20 novel five-membered cyclic silylenes, including saturated (sila)0–4 cyclopentasilylenes (1–10) and...     

Effects of Prior Annealing on the Spark Plasma Sintering of Nanostructured Y2O3 Powders

The effects produced by annealing Y₂O₃ nanopowders on their spark plasma sintering (SPS) behavior are systematically investigated in this work. It is found that the annealed powders display higher sinterability with respect to the as‐received ones. Indeed, the maximum densification level reached from pristine powders is about 97.5%, whereas density decreases when further increasing either the sintering temperature or the dwell time. In contrast, the density of SPS products obtained from pretreated powder monotonically increases with temperature and processing time, thus leading to fully dense materials in 30 min at 1050°C and 60 MPa. Correspondingly, it is found that the annealing treatment markedly inhibits grain coarsening during SPS. Thus, dense translucent samples with grain size below 100 nm can be attained from annealed powders. On the other hand, white‐opaque specimens with significantly coarser microstructures (up to 1‐μm‐sized grains) are obtained when pristine powders are directly processed under the same sintering conditions. Furthermore, it is observed that the annealing treatment of SPS samples in air allows for graphite contamination removal, whereas no improvement in term of light transmittance is produced.     

Trend Analysis and Spatial Prediction of Groundwater Levels Using Time Series Forecasting and a Novel Spatio-Temporal Method

Water Resources Management - Overexploitation of groundwater in the Malayer Plain has resulted in a continuous decline of groundwater levels over recent years with associated risks to water...     

Studying the Effect of Cobalt Doping on Optical and Magnetic Properties of Zinc Oxide Nanoparticles

Silicon - Nano-crystalline powders of Zn1−xCoxO with $\left (0.0\le x\le 0.07 \right )$ have been synthesized by sol-gel method. X-ray diffraction patterns of the prepared samples confirm the...     

The effect of pre-wetting on dynamic contact angles

A roll-coating experimental system is used to study the effect of pre-wetting on dynamic contact angles, the interfacial displacement depth, and the associated phenomenon of air entrainment. The system consists of a roll, which is horizontally rotating in a liquid pool. The dynamic contact angle is recorded by a macrophotography system. The test liquids are glycerol solutions with viscosities in the range 104 < μ < 748 mPa · s. The value of (μV/ρg)^0.5 is taken as the characteristic length to be used in the dimensionless relationships which correlate experimental measurements. The effect of base layer entry angle into the liquid pool on the dynamic contact angles and other flow parameters is studied. Comparison is made with measurements in dry tape-coating and other pre-wet roll–coating systems.     

Effect of plasticizers on the thermal decomposition of chlorinated polyvinylchloride

Plasticized samples of chlorinated polyvinylchloride (CPVC) were investigated by using thermogravimetric (TG) analysis and differential scanning calorimetry (DSC). Three different plasticizers were studied, namely, dioctyl phthalate (DOP), alkyldiaryl phosphate ester (Santiciser 2148), and triaryl phosphate ester (Reofos 50). TG experiments in nitrogen showed one major decomposition stage, involving dehydrochlorination, and minor pyrolysis reaction of the hydrocarbon residue. In contrast to the three stages previously reported to occur in the nonplasticized‐stabilized CPVC, TG analyses in air showed two distinctive decomposition stages for the plasticized CPVC samples. The DOP system provided a suggestion of a third stage. The first decomposition stage was due not only to the loss of all the chlorine present, but also to loss of the plasticizer or its decomposition products. The second decomposition stage was mostly due to char oxidation, the char being formed almost exclusively from the DCE and VDC units in CPVC polymer. DSC results showed that in the presence of nitrogen, there was no significant plasticizer effect on the thermal decomposition behavior of CPVC up to about 330°C, while in air the DSC traces also show no significant differences below 400°C. The two phosphate plasticizers showed no significant differences in their effect on the thermal decomposition behavior of CPVC under the same experimental conditions. It is believed that P₂O₅ and polyphosphoric acid are among the main constituents of the residua. These would impart a protective glassy surface to the char. This will facilitate effective flame retardant action. This preliminary conclusion is based on the premise that the more stable the char layers are, the more resilient will be the protective layer, and consequently, the better the flame retardant effect. J. VINYL ADDIT. TECHNOL., 11:21–27, 2005. © 2005 Society of Plastics Engineers