Papers by Keyword: Release

Abstract: Sodium salicylate (SS), a non-steroidal anti-inflammatory drug, was loaded into starch-based hydrogels and the release characteristics of SS therefrom was studied. The hydrogels were prepared from wheat and arrowroot starches and crosslinked with either glutaraldehyde or sodium tetraborate decahydrate (borax). SS was loaded into hydrogel at concentrations of 10 and 20%w/w based on dry weight of sample. The study of release characteristics was carried out by total immersion method for 24 h in an acetate buffer solution (pH 5.5) at 32°C as the same condition of human skin. A burst release of SS at the initial time followed by a gradual release to reach a plateau was observed. The maximum amounts of SS released from the hydrogels were about 8-22 mg. The amount of water retention of hydrogels was also determined at the same condition with that of the study of release. The hydrogels with the greater amount of water retention showed the higher release of SS. The hydrogels crosslinked with borax had higher amounts of SS released than those crosslinked with glutaraldehyde. The hydrogels containing 20% SS-loaded showed higher amounts of SS released than those containing 10% SS-loaded. The hydrogels prepared from arrowroot starch showed higher amounts of SS released than those prepared from wheat starch. From the study of release kinetics based on the Korsmeyer-Peppas model, the exponents of release (n) of all specimens were close to 1 which indicated Case II diffusion.

Abstract: In this work, vertically aligned titania nanotube arrays (TNTs) were fabricated on Ti surface in fluoride-containing electrolytes by anodization. TNTs were treated by hydrothermal treatment in the saturated solution of [Cu(NH₃)₄ (H₂O)₂]²⁺. Different hydrothermal treatment conditions were studied to obtain the best modification effect in the experiment. The TNTs were loaded with alendronate and ibuprofen via vacuum drying method and the release properties from the nanotubes were detected in phosphate buffer solution (PBS). The samples were characterized by field emission scanning electron microscopy, X-ray diffraction, and UV-Vis spectrophotometer. The data show that copper is successfully doped to the nanotube surface by hydrothermal treatment, and the optimum hydrothermal treatment conditions are 200°C, 0.5h. The drug loading capacity of the modified sample increased obviously, whether it was hydrophilic or hydrophobic. Meanwhile, the modified nanotubes release more slowly in the later stage. This approach provides an alternative to tailor the surface of TNTs and offer considerable propects for diverse biomedical applications.

Abstract: This paper study the migration characteristics and degradation kinetics of bisphenol A using TGA - gas chromatography - mass spectrometry and found that bisphenol A polycarbonate in the thermal oxidative aging conditions of 130 °C de-gradated to bisphenol A. At the range of 0 h to 120 h, the bisphenol A content of environmental hormones increased with time. When it reached 120 h, bisphenol A environmental hormone content decreased slightly with aging time. The content of bisphenol A reached 495mg/kg when the thermal oxidative aging time was 168 h, which was decreased compared to the content of 442mg/kg at 120 h. Polycarbonate thermal decomposition kinetics study showed that the thermal decomposition of polycarbonate can be divided into three phases. The first thermal decomposition occurred at the range of 415° C to 425 ° C, the polycarbonate end groups fracture of the second stage at 493.6°C , the main fracture of the main chain rearrangement and crosslinking, and the third stage at 598.7°C, the degradation of the chain continues to decompose and the decomposition of the crosslinked carbon precursor; thermal oxidation aging of polycarbonate decreased the heat stability and promote the thermal decomposition of polycarbonate. Comparing the oxidation induction period, thermal weight loss rate and activation energy of polycarbonate before and after thermal oxidative aging, it c found that the thermal stability of the hot oxygen aging of polycarbonate is reduced.

Abstract: The rapid growth in the use of corrosive gases transported by pressure vessels and pipelines has brought significant increase of risk to a number of people, both workers and public, whose life could be endangered at any one time by accident involving these chemicals. Due to the complexity of the involved physical phenomena and to the lack of an adequate amount of reliable experimental data, a number of different models and calculation procedures for estimating the consequences following the release of a corrosive gas are presently reported in the literature. The contribution deals with real scenarios of accidents associated with stationary risk facilities with corrosive flammable toxic chemicals. The study presents the results of hazardous zone calculation for the event of various corrosive liquids (Cl₂, NH₃, CCl₂O, C₃H₄O) toxic releases. The goal of this article is to present the results of the approach of modeling using the standard methods and to demonstrate the importance of the next development stage in the area of corrosive materials accident modeling of releases and dispersions in cases of accident.

Abstract: This paper aims to analyze processes of an automotive industrial company in order to identify and implement management methods to modify the volume of produced product starting with the changing request through to the handover of the first produced and approved new product status to volume production. The specialist scope extends to each volume of produced product or part thereof, irrespective of whether this was produced in-house or externally sourced. The effects of a product modification on the production process, purchased parts and production resources are included in full. A modification can be implemented with or without a modification project. If a modification is implemented within the scope of a modification project, the regulations governing product development process projects apply. The application process of modifications comprises the modification request, define modification scope, analysis of consequences and approval of modification request. The decision and responsibility to implement the modification process in volume of produced products lies to the product line manager. Every modification type constitutes a product change and can be mapped in various ways in a system.

Abstract: To prolong the bioactivity of eprinomectin (EPM), a batch of EPM-loaded PLGA microspheres were fabricated by a solvent evaporation method. The morphology of resultant microspheres was observed with an S-4800-I scanning electron microscope (SEM). The EPM release behaviors were investigated with a dialysis method and fitted with Zero-order, First-order, and Higuchi dynamical models. The optimum formula, C_PVA 2.0 w/v%, stirring rate 1, 200 r/min, C_PLGA 4.0 wt%, and oil/water ratio 1/250, was obtained from single-factor experiments. SEM images suggested that the resultant microspheres were monodispersed spheres with a few micropores on their surfaces. Furthermore, more pores and hollows were observed in the degraded PLGA matrix. EPM-loaded PLGA microspheres showed the maximum release amount in the mixture of alcohol/PBS (4/6, v/v). The release process lasted for 30 d, which increased the bioactivity and insecticidal efficacy of EPM. Besides, microspheres with the diameter of 50 μm showed a better release behavior than those from 100 μm and 150 μm ones. Therefore, such method had a promising application on sustained release of veterinary medicine.

Abstract: The negative ion release properties of an Anion PP fiber covered colored cotton textile were tested at different washing times and at the same time microstructures of an Anion PP fiber covered colored cotton textile yarn were analyzed by scanning electron microscopy (SEM). Before washing the static negative ions number of the textile was averagely 2884 per cubic centimeter and its dynamic negative ions number was 3084 per cubic centimeter on average. After washing 50 times the static and dynamic negative ions number of the textile was separately 2614 and 2398 per cubic centimeter. SEM microscopy analysis displayed that it was little that washing effect on the release of negative ion which still could meet the needs of people of anion.

Abstract: Phosphorus is a necessary nutrient element to all lives in the world. Distribution and phosphate rock reserves in the world disclose shortage crisis of phosphorus. Thus phosphorus recovery has been a research hot spot in the world. Mr.Ohtake’ group [1] recommended a new method to recover phosphorus from sewage sludge during heating process. It seems that nearly 90% of the poly-phosphate (poly-P) and 87% of total phosphate (T-P) can be released from cultivated sludge by heating at 70 °C for 1 hour. Meanwhile, released poly-P can precipitate with Ca in neutral condition without any pH adjustment. Sewage sludge was used in this research to identify its performance during thermal treatment. With the increase of temperature and heating time, release of poly-P and T-P increased obviously. However, poly-P would be hydrolyzed when temperature was higher than 80 °C. With addition of EDTA, release of poly-P increased nearly 100%. Migration of metal cations during thermal treatment can provide indirect evidence which kinds of metal cations would make impediment on poly-P release. A novel phenomenon was observed poly-P mixed with ortho-phosphate can precipitate with NH₄⁺ and Mg²⁺ as struvite at pH 8.5.

Abstract: According to different melting point of paraffin type of PCM, has carried out some experimental research and analysis, through the visualization experiment method, the PCM phase change expansion coefficient is determined. At the same time, under the same conditions, for 30 #, 40 #, 50 # PCM storage heat release experiments, contrast analysis of the regenerative heat release, total heat release, and storage time on average water temperature difference factors. In addition, carried out more than melting point PCM cascade configuration related experimental heat storage properties, expect to achieve energy utilization efficiency.

Abstract: Effect of organic matter and organic acid on the heavy metals, especially, chromium (Cr) release in the sediment was researched. Glucose and soluble organic starch was used as organic matter, as well, citric acid and ethylene diamine tetraacetic acid (EDTA) were simulated as organic acid. The results showed that best adsorption time of glucose on Cr was 5h, the optimal dosage was 0.1g g^-1; best adsorption time of organic soluble starch was 4h, and the optimum adding amount of 0.08g/g; best adsorption time of citric acid was 5h, the best concentration 0.005mol g^-1; optimal adsorption time of organic acid EDTA was 3h, the optimum adding amount of 0.12g g^-1. Glucose, soluble starch and citric acid significantly effected on the release of Cr in the sediment, however, influence of EDTA on the release of Cr was not so evident.