Hydrogels for the management of second-degree burns:currently available options and future promise

Burn wounds result from exposure to hot liquids,chemicals,fire,electric discharge or radiation.Wound severity ranges from first-degree injury,which is superficial,to fourth-degree injury,which exposes bone,tendons and muscles.Rapid assessment of burn depth and accurate wound management in the outpatient setting is critical to prevent injury progression into deeper layers of the dermis.Injury progression is of particular pertinence to second-degree burns,which are the most common form of thermal burn.As our understanding of wound healing advances,treatment options and technologies for second-degree burn management also evolve.Polymeric hydrogels are a class of burn wound dressings that adhere to tissue,absorb wound exudate,protect from the environment,can be transparent facilitating serial wound evaluation and,in some cases,enable facile removal for dressing changes.This review briefly describes the burn level classification and common,commercially available dressings used to treat second-degree burns,and then focuses on new polymeric hydrogel burn dressings under preclinical development analyzing their design,structure and performance.The review presents the follow key learning points:(1)introduction to the integument system and the wound-healing process;(2)classification of burns according to severity and clinical appearance;(3)available dressings currently used for second-degree burns;(4)introduction to hydrogels and their preparation and characterization techniques;and(5)pre-clinical hydrogel burn wound dressings currently being developed.

二次移动平均模型在经济预测中的应用

利用二次移动平均模型,引入均方拟合误差最小的原理确定出时段数N,对国民经济总收入、人口数量等项目进行了预测。

Optimization of Quantizer’s Segment Threshold Using Spline Approximations for Optimal Compressor Function

In this paper, the optimization of quantizer’s segment threshold is done. The quantizer is designed on the basis of approximative spline functions. Coefficients on which we form approximative spline functions are calculated by minimization mean square error (MSE). For coefficients determined in this way, spline functions by which optimal compressor function is approximated are obtained. For the quantizer designed on the basis of approximative spline functions, segment threshold is numerically determined depending on maximal value of the signal to quantization noise ratio (SQNR). Thus, quantizer with optimized segment threshold is achieved. It is shown that by quantizer model designed in this way and proposed in this paper, the SQNR that is very close to SQNR of nonlinear optimal companding quantizer is achieved.

Obstruction of the formation of granulation tissue leads to delayed wound healing after scald burn injury in mice

Background:Delayed wound healing remains a common but challenging problem in patients with acute or chronic wound following accidental scald burn injury.However,the systematic and detailed evaluation of the scald burn injury,including second-degree deep scald(SDDS)and thirddegree scald(TDS),is still unclear.The present study aims to analyze the wound-healing speed,the formation of granulation tissue,and the healing quality after cutaneous damage.Methods:In order to assess SDDS and TDS,the models of SDDS and TDS were established using a scald instrument in C57BL/6 mice.Furthermore,an excisional wound was administered on the dorsal surface in mice(Cut group).The wound-healing rate was first analyzed at days 0,3,5,7,15 and 27,with the Cut group as a control.Then,on the full-thickness wounds,hematoxylin and eosin(H&E)staining,Masson staining,Sirius red staining,Victoria blue staining and immunohistochemistry were performed to examine re-epithelialization,the formation of granulation tissue,vascularization,inflammatory infiltration and the healing quality at different time points in the Cut,SDDS and TDS groups.Results:The presented data revealed that the wound-healing rate was higher in the Cut group,when compared with the SDDS and TDS groups.H&E staining showed that re-epithelialization,formation of granulation tissue and inflammatory infiltration were greater in the Cut group,when compared with the SDDS and TDS groups.Immunohistochemistry revealed that the number of CD31,vascular endothelial growth factor A,transforming growth factor-βandα-smooth muscle actin reached preferential peak in the Cut group,when compared with other groups.In addition,Masson staining,Sirius red staining,Victoria blue staining,Gordon-Sweets staining and stress analysis indicated that the ratio of collagen I to III,reticular fibers,failure stress,Young’s modulus and failure length in the SDDS group were similar to those in the normal group,suggesting that healing quality was better in the SDDS group,when compared with the Cut and TDS groups.Conclusion:Overall,the investigators first administered a comprehensive analysis in the Cut,SDDS and TDS groups through in vivo experiments,which further proved that the obstacle of the formation of granulation tissue leads to delayed wound healing after scald burn injury in mice.