BACKGROUND:Degradable polymer materials initiate the degradation process immediately after implantation. How to regulate the degradation of these materials is rarely reported at present. OBJECTIVE:To study the effect of ultrasonic wave on control ing the degradation of polymer materials. METHODS:The sample is made ofε-caprolactone/L-lactide copolymer, and its core was coated with low density polyethylene on the surface with the fol owing four different methods. (1) The core surface was firstly covered with CaCl 2 powder, and then coated with polyethylene. (2) The core was firstly coated with polyethylene and coarsened for 3 hours. (3) The core surface was firstly covered with CaCl 2 powder, and then coated with polyethylene, and coarsened for 3 hours. (4) The core was directly coated with polyethylene. The four kinds of specimens obtained were embedded in pork for ultrasonic bombardment experiment in vitro. RESULTS AND CONCLUSION:In the specimens prepared with methods 1 and 4, the lyophobic layer could protect core materials before ultrasonic treatment, and no absorption peak was found at 631 nm. After ultrasonic treatment, the lyophobic layer was destroyed, toluidine blue dye was released, leading to change the color of immersion solution and increase the absorption peak at 631 nm. In the specimens prepared with methods 2 and 3,the lyophobic layer cannot exhibit the protection effects, the absorption peak was found at 631 nm. Under electron microscope, the appearance of the specimens in four groups was changed obviously. It is feasible to control the starting of the degradation by coating the degradable copolymer with LDPE and using ultrasonic as a trigger.

Objective To investigate the current status of hand hygiene(HH) among health care workers(HCWs) in clinical laboratories in medical institutions in Xi'an City.Methods HH status of HCWs in clinical laboratories in medical institutions in Xi'an was performed random on-the-spot sampling and monitoring.Results A total of 240 HH specimens of HCWs in clinical laboratories in 80 medical institutions in Xi'an City were collected, 127 detected results were qualified, the total qualified rate was 52.92%.The qualified rates of medical institutions were as follows: municipal hospitals 62.67%,workers' hospitals 55.95%,private hospitals 40.74%;comprehensive medical institutions 67.68%,specialized medical institutions 42.55%;tertiary medical institutions 79.63%(n=43),secondary and below medical institutions 45.16%(n=84),there were significant differences in HH qualified rate among HCWs in different types of medical institutions(all P<0.01).Of different HH detection items, detection rates of Escherichia coli and Staphylococcus aureus were 0.83% and 8.33% respectively.There were significant differences in HH compliance rates among HCWs of all age groups(χ2=9.103,P<0.05), HCWs aged≥50 years had the highest qualified rate of HH(71.43%), followed by those aged<30 years (67.82%),HCWs in 40~ year age group had the lowest HH qualified rate (39.66%).Conclusion The qualified rate of HH of HCWs in clinical laboratory of medical institutions in Xi'an City is low, it is necessary to enhance the procaution awareness of HCWs in clinical laboratories, strengthen quality control of HH, strictly implement standard hand-washing procedures to reduce occurrence of HAI.

OBJECTIVES: This study aims to determine the effects of low-level laser (LLL) on the expression of interleukin-6 (IL-6), tumor necrosis factor (TNF)-α, osteoprotegerin (OPG), and receptor activator of nuclear factor-κB ligand (RANKL) in human periodontal ligament cells (HPDLCs) stimulated by high glucose; and identify the molecular mechanism of LLL therapy in the regulation of periodontal inflammation and bone remodeling during orthodontic treatment in diabetic patients. METHODS: HPDLCs were cultured in vitro to simulate orthodontic after loading and irradiated with LLL therapy. The cultured cells were randomly divided into four groups: low glucose Dulbecco's modification of Eagle's medium (DMEM)+stress stimulation (group A), high glucose DMEM+stress stimulation (group B), hypoglycemic DMEM+LLL therapy+stress stimulation (group C), and hyperglycemic DMEM+LLL therapy+stress stimulation (group D). Groups C and D were further divided into C1 and D1 (energy density: 3.75 J/cm²) and C2 and D2 (energy density: 5.625 J/cm²). Cells in groups A, B, C, and D were irradiated by LLL before irradiation. At 0, 12, 24, 48, and 72 h, the supernatants of the cell cultures were extracted at regular intervals, and the protein expression levels of IL-6, TNF-α, OPG, and RANKL were detected by enzyme-linked immunosorbent assay. RESULTS: 1) The levels of IL-6 and TNF-α secreted by HPDLCs increased gradually with time under static pressure stimulation. After 12 h, the levels of IL-6 and TNF-α secreted by HPDLCs in group A were significantly higher than those in groups B, C1, and C2 (P<0.05), which in group B were significantly higher than those in groups D1, and D2 (P<0.01). 2) The OPG protein concentration showed an upward trend before 24 h and a downward trend thereafter. The RANKL protein concentration increased, whereas the OPG/RANKL ratio decreased with time. Significant differen-ces in OPG, RANKL, and OPG/RANKL ratio were found among group A and groups B, C1, C2 as well as group B and groups D1, D2 (P<0.05). CONCLUSIONS 1) In the high glucose+stress stimulation environment, the concentrations of IL-6 and TNF-α secreted by HPDLCs increased with time, the expression of OPG decreased, the expression of RANKL increased, and the ratio of OPG/RANKL decreased. As such, high glucose environment can promote bone resorption. After LLL therapy, the levels of IL-6 and TNF-α decreased, indicating that LLL therapy could antagonize the increase in the levels of inflammatory factors induced by high glucose environment and upregulate the expression of OPG in human HPDLCs, downregulation of RANKL expression in HPDLCs resulted in the upregulation of the ratio of OPG/RANKL and reversed the imbalance of bone metabolism induced by high glucose levels. 2) The decrease in inflammatory factors and the regulation of bone metabolism in HPDLCs were enhanced with increasing laser energy density within 3.75-5.625 J/cm². Hence, the ability of LLL therapy to modulate bone remodeling increases with increasing dose.
Humans ; Osteoprotegerin ; Tumor Necrosis Factor-alpha/metabolism* ; Interleukin-6/pharmacology* ; RANK Ligand/pharmacology* ; Periodontal Ligament/metabolism* ; Lasers ; Glucose/pharmacology*