Effects of thermal cycling on bonding properties of novel low-shrinkage resin adhesive / 华西口腔医学杂志

OBJECTIVES@#The current study aimed to investigate the bonding properties of a novel low-shrinkage resin adhesive containing expanding monomer and epoxy resin monomer after thermal cycling aging treatment.@*METHODS@#Expanding monomer of 3,9-diethyl-3,9-dimethylol-1,5,7,11-tetraoxaspiro-[5,5] undecane (DDTU) as an anti-shrinkage additive and unsaturated epoxy monomer of diallyl bisphenol A diglycidyl ether (DBDE) as a coupling agent were synthesized. A blend of DDTU and DBDE at a mass ratio of 1∶1, referred to as "UE", was added into the resin matrix at the mass fraction of 20% to prepare a novel low-shrinkage resin adhesive.Then, the methacrylate resin adhesive without UE was used as the blank control group, and a commercial resin adhesive system was selected as the commercial control group. Moreover, the resin-dentin bonding and micro-leakage testing specimens were prepared for the thermal cycling aging treatment. The bonding strength was tested, the fracture modes were calculated, the bonding fracture surface was observed by scanning electron microscope (SEM), and the dye penetration was used to evaluate the tooth-restoration marginal interface micro-leakage. All the data were analyzed statistically.@*RESULTS@#After aging, the dentin bonding strength of the experimental group was (19.20±1.03) MPa without a significant decrease (P>0.05), that of the blank control group was (11.22±1.48) MPa with a significant decrease (P<0.05) and that of the commercial control group was (19.16±1.68) MPa without a significant decrease (P>0.05). The interface fracture was observed as the main fracture mode in each group after thermal cycling by SEM. The fractured bonding surfaces of the experimental group often occurred on the top of the hybrid layer, whereas those of the blank and commercial control groups mostly occurred on the bottom of the hybrid layer. Micro-leakage rating counts of specimens before and after thermal cycling were as follows: the experimental group was primarily 0 grade, thereby indicating that a relatively ideal marginal sealing effect could be achieved (P>0.05); meanwhile, the blank control group was primarily 1 grade, and the penetration depth of dye significantly increased after thermal cycling (P<0.05); the commercial control group was primarily 0 grade without statistical difference before and after thermal cycling (P>0.05), while a significant difference was observed between the commercial control group and experimental group after thermal cycling (P<0.05).@*CONCLUSIONS@#The novel low-shrinkage resin adhesive containing 20%UE exhibited excellent bonding properties even after thermal cycling aging treatment, thereby showing a promising prospect for dental application.

Effect of leukocyte-depleted suspended red blood cells storaged for different time on patients with hematologic diseases and malignant tumors / 中国输血杂志

【Objective】 To investigate the effect of leukocyte-depleted suspended red blood cells (lds-RBCs) storaged for different time on blood transfusion effect of patients with hematologic diseases and malignant tumors, as well as to evaluate the storage quality of lds-RBCs in blood stations. 【Methods】 Seven hospitals (4 tertiary-A hospitals and 3 secondary-A hospitals), applying for blood from our blood center, were selected. Blood transfusion cases (medical record) and related data (indicators) of patients with blood diseases and malignant tumors in those hospitals from December 2018 to May 2019 were collected, including disease diagnosis (type) before transfusion, demographic characteristics, date of solo transfusion of lds-RBCs, units of lds-RBCs [(1~2)U/bag, 1 U=200 mL whole blood], different storage duration (1~5 weeks) (bar code), and hemoglobin (Hb) 48 h before and after transfusion. The efficacy of lds-RBCs (storaged for different time) transfusion in patients with hematologic diseases and malignant tumors was evaluated by statistical analysis. 【Results】 A total of 3 557 patients with hematologic diseases and malignant tumors were enrolled in this study. No significant changes were noticed in transfusion efficacy by blood transfusion unit, gender and previous transfusion history (P > 0.05). The effective rate of lds-RBCs in patients with blood diseases and malignant tumors, stratified by storage duration, i. e. storaged for >1~2 weeks, >2~3 weeks, >3~4 weeks and more than >4~5 weeks, was 78.77% vs 77.68% vs 75.06% vs 70.37%, and 79.32% vs 76.73% vs 72.79% vs 67.65%, respectively(P<0.05), with lds-RBCs of 4-5 storage weeks presenting the lowest transfusion efficacy in both groups of patients. 【Conclusion】 The storage time of most lds-RBCs supplied by our center is moren than 3 weeks, and the transfusion effect of lds-RBCs stored for 5 weeks needs further observation. In order to ensure and improve the efficacy of blood transfusion, evidence-based medicine and information management are needed to help the clinical gasp the advantageous time of blood products and shorten the storage-to-transfusion time of red blood cells.

Inhibitors and their effects on Saccharomyces cerevisiae and relevant countermeasures in bioprocess of ethanol production from lignocellulose--a review / 生物工程学报

The pretreatment of raw materials is necessary for ethanol production from lignocellulose, however, a variety of compounds which inhibit the fermenting microorganism such as Saccharomyces cerevisiae are inevitably formed in this bioprocess. Based on their chemical properties, the inhibitors are usually divided into three major groups: weak acids, furaldehydes and phenolic compounds. These compounds negatively affect the growth of S. cerevisiae, ethanol yield and productivity, which is one of the significant hurdles for the development of large-scale ethanol production from lignocellulose. We address here the origins of the three kinds of inhibitors and their mechanisms to S. cerevisiae. We also discuss the strategies of improving the fermentation performance of yeast, including detoxification of the pretreated substrates, enhancement of yeast tolerance and also fermentation control to reduce the effects of the inhibitors. The methods used in enhancing the yeast tolerance are traditional mutagenic breeding integrated with strains evolution under the suitable selective pressure, and metabolic engineering by introducing and/or overexpressing genes encoding enzymes such as furfural reductase, laccase and phenylacrylic acid decarboxylase, that confer the S. cerevisiae strains resistance towards specific inhibitors.