جستجوی مقالات مرتبط با کلیدواژه "hydrogel" در نشریات گروه "جنگلداری"

In dry areas, the lack of rainfall, inappropriate seasonal distribution, and high evaporation and transpiration, and on the other hand, high water supply costs, cause the loss of seedlings, especially in the critical period of establishment. In the present study, the effects of different moisture storage treatments on the quantitative and qualitative growth of Cercis siliguastrum L., Celtis caucasica Wild., Elaeagnus angustifolia L. and Amygdalus scoparia Spach plantations were studied in the Semnan University. This experiment was conducted in a completely randomized design with five treatments: i) soil texture modification, ii) use of hydrogels, iii) zeolites and iv) straw with crushed stone and v) control (natural soil of region) with five replications and totally 300 seedlings of the species. The height, collar and crown diameter, number and length of lateral branches were measured at the beginning and the end of the growth period and survival rate of all seedlings were recorded at the end of growing period.  In Cercis siliguastrum, the highest growth of collar diameter, crown and length of lateral branches were measured under straw treatment.. In Amygdalus scoparia, the highest quantitative growth values were observed in straw treatment. In Elaeagnus angustifolia and Celtis caucasica , different treatments had no significant effects on growth parameters. Different storage treatments had no effect of survival of investigated species. The lowest survival rate (with a range of 80-88%) was related to Amygdalus scoparia seedling and no significant difference was observed in this factor amongst other species. The type and efficiency of moisture storage methods are different according to the type of species used, the straw and crushed stone treatment was effective in the growth of Celtis caucasica and Amygdalus scoparia seedlings. In contrast, Celtis caucasica had the highest growth in the natural soil. On the other hand, none of the investigated moisture storage treatments had no effect on the vegetative characteristics of Elaeagnus angustifolia seedlings. Furthermore, the use of hydrogel and zeolite had no positive effect on the growth and establishment of the investigated species.

In this study, efficient hybrid hydrogels as drug delivery platforms were synthesized using Kraft lignin, a biopolymer obtained from the alkaline paper industry, chitosan and glutaraldehyde as a crosslinker. The ratio of lignin was an important variable factor of this study and its effect on morphology and mechanical properties were studied. The characteristics such as compressive property, swelling capacity, drug release, degradation time, and SEM imaging of the hydrogels of chitosan and chitosan/ lignin with different amount of lignin were investigated. Also, paracetamol drug was selected as a drug model. The results showed that the glutaraldehyde crosslinker can effectively create a crosslinked structure, so that the durability and stability of the hydrogels in the desired conditions is up to 15 days for the pure chitosan sample and 11 days for the lignin chitosan sample, respectively. Although the shortest shelf life (5 days) corresponds to the highest amount of lignin, which was a shorter period of time, but it gives enough time for the drug to be completely released. The results showed that although the hydrogel structure is weakened by increasing the percentage of lignin, the drug was released faster with the increasing of lignin, which can be considered as a factor for changing the release rate of drug according to the intended application. The highest amount of release was observed in hydrogels with the highest amount of lignin, so that in the first two hours, its amount was about six times higher than that of pure chitosan hydrogel.