Formulation and in-vitro Evaluation of Carvedilol Gastroretentive Capsule as (Superporous Hydrogel)

The preferred route of drug administration is the oral route, but drugs with narrow absorption window in the gastrointestinal tract are still challenging. The ability to extend and monitor the gastric emptying time is a valuable tool for processes remaining in the stomach longer than other traditional dosage forms. The purpose of this study was to formulate and evaluate gastroretentive superporous hydrogel (SPH) of carvedilol with view to improve its solubility and increase gastric residence time in order to get sustained release formulas via utilization of various kinds and concentrations of hydrophilic polymers then after, incorporate the best prepared formula into capsules. Sixteenth formulae of SPH hybrid were prepared by gas blowing technique from the following materials; monomers (Poly vinyl alcohol, and Acrylamide), cross-linkers (Methylene bisacrylamide, and glutaraldehyde), hybrid agent (Chitosan), foaming agent (NaHCO3) and foam stabilizer (Tween 80). Different amounts or concentrations of these materials were utilized to investigate their effect on SPH properties (density, porosity, floating, drug content, drug release, swelling time, and swelling ratio). The soaking procedure was utilized for loading of carvedilol into SPH hybrid (6.25mg/2.5g SPH). After analysis the results statistically and application the similarity factor (f2) equation, formula F8 was selected as the best formula and incorporated into capsules. The drug release data were applied to different mathematical kinetics and the results were shown to be fitted to Higuchi model and the release mechanism was (non fickian) diffusion. The overall results suggested that the proposed SPH hybrid drug delivery system is encouraging for carvedilol specific delivery to the stomach.

Spore-forming bacteria in the dairy chain

Spore-forming bacteria form the most diverse and most complex group of bacteria in terms of their elimination from the dairy chain, due to their ability to form highly resistant spores. As ubiquitous microorganisms, spore-formers can enter the product along the milk-processing continuum from different sources, and subsequently cause spoilage in various types of dairy products. The most important classes of spore-forming bacteria relevant to the dairy industry are Bacilli and Clostridia. Bacilli are responsible mainly for the spoilage and decreased shelf-life of fluid milk, while Clostridia cause late gas blowing in cheese. Spore-forming microorganisms contaminate raw milk primarily at the farm level, with potential for recontamination to occur at various points along the dairy production continuum. The most effective measure in reducing spore load at the farm level is adequate pre-milking teat preparation, while at the dairy plant level, bactofugation and microfiltration are applied. Understanding the ecology of spore-formers can improve application of systematic approaches for controlling the spoilage bacteria in dairy processing systems. Also, novel technologies, such as high-pressure processing, ultrasound treatment, irradiation etc., could provide the dairy industry with the powerful tools to eliminate these bacteria from the dairy chain.

Technologies of refining of aluminum alloys by gas blowing

The results of the analysis of various methods of refining aluminum alloys from dissolved gases and non-metallic inclusions are presented. The influence of a number of technological features of each method on the quality of the melt has been studied. Examples of equipment for the implementation of processes are presented. To analyze the effectiveness of the use of various technologies for refining aluminum alloys, their ranking was carried out. The results of the analysis are in correlation with the trends in the spread of various processes for the refining of aluminum alloys in foundries. It is shown that blowing the melt with inert gases through a rotating impeller is the most effective in terms of a set of indicators in comparison with other methods.

Effect of Froude Number on Submerged Gas Blowing Characteristics

The flow behavior of gas in compressible and incompressible systems was investigated at an ambient temperature in an air–water system and at an operating process temperature in the IronArc system, using computational fluid dynamics. The simulation results were verified by experiments in the air–water system and established empirical equations to enable reliable predictions of the penetration length. The simulations in the air–water system were found to replicate the experimental behavior using both the incompressible and compressible models, with only small deviations of 7–8%. A lower requirement for the modified Froude number of the gas blowing to produce a jetting behavior was also found. For gas blowing below the required modified Froude number, the results illustrate that the gas will form large pulsating bubbles instead of a steady jet, which causes the empirical equation calculations to severely underpredict the penetration length. The lower modified Froude number limit was also found to be system dependent and to have an approximate value of 300 for the studied IronArc system. For submerged blowing applications, it was found that it is important to ensure sufficiently high modified Froude numbers of the gas blowing. Then, the gas penetration length will remain stable as a jet and it will be possible to predict the values using empirical equations.

MODELING OF A VENTILATED CAVITY BEHIND A STREAMLINED BODY

The results of physical and numerical modeling of a ventilated air cavity behind a streamlined body are presented. The results of laboratory experiments to determine the amount of gas flowing from the ventilated cavity are presented. It is formed behind the cavitator depending on a number of geometric and dynamic parameters. Numerical simulation of non-stationary 3D two-phase flow was performed on the basis of open source software OpenFOAM. The influence of gas blowing parameters on the formation of an air cavity, size, shape and stability has been investigated. Good qualitative agreement with experimental data was obtained. It is shown that the thickness of the ventilated cavity is determined by the diameter of the cavitator regardless of the diameter of the blow hole, and the increase in velocity or gas flow rate has a positive effect on the length and stability of the formed cavity.

A WAY TO INCREASE THE EFFICIENCY OF WATER ISOLATING WORKS USING WATER REPELLENT

A method for isolating water inflow in gas wells is proposed, which consists in pumping a water-insulating composition into the water saturated interval using gas as a blowing fluid. The results of studies on physical models of the reservoir are presented, which prove an increase in the penetrating ability of the water repellent, blockage density of water-permeable channels and a decrease in phase permeability of water. These results were obtained in both water and gas saturated porous mediums. It is observed also that the gas blowing of a water isolating composition contributes in reduction of the reverse removal of the composition from theporous medium, as a result of a more uniform distribution of the water isolating composition in the porous medium.

A Critical Review on Crystal Growth Techniques for Scalable Deposition of Photovoltaic Perovskite Thin Films

Although the efficiency of small-size perovskite solar cells (PSCs) has reached an incredible level of 25.25%, there is still a substantial loss in performance when switching from small size devices to large-scale solar modules. The large efficiency deficit is primarily associated with the big challenge of coating homogeneous, large-area, high-quality thin films via scalable processes. Here, we provide a comprehensive understanding of the nucleation and crystal growth kinetics, which are the key steps for perovskite film formation. Several thin-film crystallization techniques, including antisolvent, hot-casting, vacuum quenching, and gas blowing, are then summarized to distinguish their applications for scalable fabrication of perovskite thin films. In viewing the essential importance of the film morphology on device performance, several strategies including additive engineering, Lewis acid-based approach, solvent annealing, etc., which are capable of modulating the crystal morphology of perovskite film, are discussed. Finally, we summarize the recent progress in the scalable deposition of large-scale perovskite thin film for high-performance devices.