BACKGROUND:With computer-aided design,melt electrowriting technology can precisely construct 3D tissue engineering scaffolds with specific morphology,which has attracted increasing attention in tissue engineering. OBJECTIVE:To elaborate on the progress of melt electrowriting technology in tissue engineering in recent years. METHODS:PubMed and CNKI were used to retrieve articles about applications of melt electrowriting technology in tissue engineering.The search time was from March 2008 to February 2023.The search terms were"melt electrowriting,melt electrospinning,electrospinning,tissue engineering,scaffold,regeneration"in English and"melt electrowriting,electrospinning,tissue engineering"in Chinese.A preliminary screening of articles was performed by reading the titles and abstracts.Finally,69 articles were included for review. RESULTS AND CONCLUSION:(1)Melt electrowriting technology can achieve precise layer-by-layer deposition of fibers compared to traditional electrospinning technology,which better simulates the complex structure of natural tissues.Compared to other 3D printing technologies,smaller-diameter fibers can be prepared by melt electrowriting technology,resulting in highly ordered porous structures.(2)By combining with other scaffold preparation techniques or materials,such as fused deposition modeling,solution electrospinning technology,and hydrogel,melt electrowriting technology shows great potential in preparing complex tissue engineering scaffolds,which provides certain possibilities for achieving complex tissue regeneration.(3)The regeneration of complex tissues often involves blood vessels,nerves,and soft and hard tissues at the same time.The regeneration of blood vessels and nerves is of great significance to realize the physiological reconstruction of tissues.However,soft and hard tissues have certain difficulties to realize the coordinated regeneration of both due to their different biological and mechanical properties.Melt electrowriting technology has certain advantages in the field of bionic scaffolds due to its good biocompatibility,the ability to prepare multi-scale scaffolds and high porosity.

Objective:To investigate the effects of Porphyromonas gingivalis derived outer membrane vesicles (Pg OMV) on osteoclast differentiation of macrophages and its underlying mechanisms. Methods:The morphology and the size distribution of Pg OMV were analyzed by transmission electron microscopy and nanoparticle tracing analysis, respectively. The osteoclast precursors were treated with 1, 3 and 10 mg/L Pg OMV (1, 3 and 10 mg/L OMV treatment group) or phosphate buffer solution (PBS)(control group). The formation of osteoclasts was analyzed by tartrate-resistant acid phosphase (TRAP) staining and F-actin staining and real-time quantitative PCR (RT-qPCR) were used to detect the expression of Fos and matrix metallopeptidase 9 (MMP9). Polymyxin B (PMB) was used to block lipopolysaccharide (LPS) and then Pg OMV was used to treat osteoclast precursor (PMB-OMV treatment group), and OMV treatment group was used as control. TRAP and F-actin staining were used to observe the formation of osteoclasts and actin rings. The effect of Pg OMV on the expression of Toll-like receptor (TLR) 2 and TLR4 in preosteoclasts was detected by Western blotting. The osteoclast precursors were pretreated with 10, 50, 100 and 200 μmol/L C29, an inhibitor of TLR2, and then treated with Pg OMV(OMV+10, 50, 100 and 200 μmol/L C29 treatment group) and OMV treatment group without C29 pretreatment was control. TRAP and F-actin staining were used to observe the formation of osteoclasts and actin rings. The osteoclast precursor cells were treated with OMV (OMV treatment group) and OMV incubated with PMB (PMB-OMV treatment group) and the expression of TLR2 in osteoclast precursor was detected by Western blotting.Results:Pg OMV showed classical vesicular structures, and the average particle size of Pg OMV were 179.2 nm. A large number of actin rings were observed in the 3 and 10 mg/L OMV treatment groups. The percentages of TRAP-positive osteoclast area in 3 mg/L OMV treatment group [(22.6±2.1)%] and 10 mg/L OMV treatment group [(32.0±2.3)%] were significantly increased compared with control group [(4.9±0.5)%] ( P<0.001). Compared with the control group (1.000±0.029), the mRNA relative expression of Fos in 3 mg/L OMV treatment group (1.491±0.114) and 10 mg/L OMV treatment group (1.726±0.254) was significantly increased ( P=0.013, P=0.001). Compared with the control group (1.007±0.148), the mRNA relative expression of MMP9 in the group of 10 mg/L OMV (2.232±0.097) was significantly increased ( P<0.001). Actin ring formation was less in PMB-OMV treatment groups than in OMV treatment groups. The proportion of TRAP-positive osteoclasts area [(14.8±3.8)%] in PMB-OMV treatment group was significantly lower than OMV treatment group [(31.5±6.7) %] ( P=0.004). The relative expression of TLR2 in OMV treatment group (1.359±0.134) was significantly higher than that in the control group (1.000±0.000) ( t=4.62, P=0.044). Compared with the OMV treatment group [(29.4±1.7)%], 50, 100 and 200 μmol/L C29 significantly decreased the formation of osteoclasts [(24.0±1.7)%, (18.5±2.1)%, (9.1±1.3) %] ( P=0.026, P<0.001, P<0.001). TLR2 protein expression in PMB-OMV group (0.780±0.046) was significantly lower than that in OMV group (1.000±0.000)( t=8.32, P=0.001). Conclusions:Pg OMV can promote osteoclast differentiation by carrying LPS, TLR2 plays an important role in Pg OMV mediated osteoclast differentiation.

Objective:To investigate the preoperative ascending aorta diameter in patients with acute type A aortic dissection in the Chinese population, compares and analyze the differences in preoperative blood biomarkers, and evaluate the impact of the preoperative ascending aorta diameter in this part of patients on the short-term prognosis of patients.Methods:A collection of 641 patients with acute type A aortic dissection who were enrolled in the " Acute Aortic Syndrome High-Risk Early Warning and Intervention Study" project from January 2018 to January 2020 were collected. Divide the patients into two groups (group Ⅰ<55 mm, group Ⅱ≥55 mm) according to the preventive intervention value of ascending aorta diameter recommended by the guideline for studying preoperative ascending aorta diameter difference in blood biomarkers and the influence of ascending aorta diameter on the short-term prognosis of patients. All patients had CT scans to assess the diameter of the ascending aorta before operation.Results:In this study, all patients with acute type A aortic dissection had a mean preoperative ascending aorta diameter of (46.9±9.7)mm. The preoperative ascending aorta diameter of all patients was less than 55 mm, accounted for 84.1%. Male patients were more likely to have aortic dissection than females; most patients' age was less than 60 years old. The preoperative blood inflammatory index counts were higher in the ascending aorta diameter ≥55 mm group. However, the long-term prognosis of patients with different ascending aorta diameters before surgery was not apparent in this study. The preoperative survival rate and short-term survival rate of patients with ascending aorta diameter <55 mm were higher than those of other groups, but the difference was not statistically significant.Conclusion:In patients with acute type A aortic dissection, the diameter of the ascending aorta is usually less than 55 mm. Moreover, the blood inflammatory index counts are high in the preoperative ascending aorta diameter ≥55 mm group. Meanwhile, patients with smaller ascending aorta diameter have better survival rate and short-term prognosis.

Ocular choristoma is composed of ectopic tissues with normal structures. The pathogenesis still remains uncertain. Histopathologically, it is a dense connective tissue mixed with epidermal appendages, smooth muscle cells, mature adipose tissue, lacrimal glands, lymph nodes, skeletal muscle fibers, cartilage and bone. Because of its low incidence, most of published literature are case reports. The clinical manifestations are non-specific and we need to distinguish it from other ocular masses. The choice of surgical resection depends on the ocular symptoms, the effect on appearance, and the need for clinical confirmation. This paper reviews the epidemiology, etiology, pathogenesis, clinical manifestations, diagnosis, differential diagnosis and treatment of ocular choristoma.

【Objective】 To analyze the influence of different Inc parameters in the Monaco planning system on the left breast cancer volumetric modulated arc therapy (VMAT) planning, in the hope of providing some reference for plan design. 【Methods】 Seventeen left-breast cancer patients who were receiving radical radiotherapy were selected. The plans were enrolled in the design of VMAT with the same optimization conditions but different Inc parameters in the Monaco planning system. All plans used different Inc parameters like 10°, 20°, 30°, and 40°. The results of the plan were compared. The dosimetric parameters of the PTV and the organs at risk inquired by the plan were analyzed. The SPSS software was used for calculating the differences between the VMAT plans and evaluating the quality of the plans. 【Results】 The different Inc parameters affected the dosimetric parameters D98%, D2%, D50%, V55 Gy of PTV and CI, HI (F=10.528, F=15.154, F=15.513, F=16.979, F=4.632, F=14.277, all P<0.05). The MU of the four groups significantly differed (F=4.632, P<0.05), and the difference of V10 on the ipsilateral lung was significant (F= 3.324, P<0.05), the remaining parameters in the four groups had no statistically significant difference. 【Conclusion】 For the left-breast cancer volumetric modulated arc therapy, the smaller of Inc parameter on the plan had better dose distribution and conformity index while the monitor units increased. 40° was not suitable for the breast cancer VMAT plan, and the high amount beyond the range would increase the toxic and side effects on the skin.

Objective:To explore the effect of online and offline blended scenario simulation teaching in the practice of nursing undergraduates.Methods:From August 2020 to May 2021, convenience sampling was used to select 76 nursing undergraduates in the class of 2017 who practiced in the Cardiology Department of the Second Affiliated Hospital of Harbin Medical University as the research object. The undergraduates were randomly divided into the experimental group and the control group, 38 in each group. The control group received the traditional graduation practice training, and the experimental group received online and offline blended scenario simulation teaching on this basis. After the practice, the clinical thinking ability of the two groups of students was evaluated by the Clinical Thinking Ability Evaluation Scale, the clinical practice ability of the two groups of students was evaluated by the Objective Structured Clinical Examination (OSCE) , and a teaching satisfaction survey was conducted.Results:The total score of clinical thinking ability, critical thinking ability, systematic thinking ability, evidence-based thinking ability, OSCE total score of the students in the experimental group were higher than those in the control group, and the differences were statistically significant ( P<0.05) . The students in the experimental group thought that the teaching method was helpful for in-depth understanding and application of theoretical knowledge, improving nursing assessment skills, clinical coping skills and communication skills, and at the same time helping to cultivate critical thinking and teamwork awareness, and arouse learning enthusiasm, and the differences were statistically significant (all P<0.05) . Conclusions:The online and offline blended scenario simulation teaching can effectively improve the clinical thinking ability, clinical practice ability and teaching satisfaction of nursing undergraduates, and it has good effect in the graduation practice of undergraduate nursing students.

Objective To compare the dosimetric differences in volumetric modulated arc therapy (VMAT) of Monaco planning system for nasopharyngeal carcinoma between Pareto and Constrained optimization in order to provide a reference for future mode selection. Methods Select 20 patients with nasopharyngeal carcinoma whom were calculated by Pareto and Constrained modes in the same CT image. Prescription dose of target PGTV, PTV1 and PTV2 was 70.29、60.39 and 54.45 Gy with 33 fractions, 5 times a week. The differences in target dose, organs at-risk dose, monitor units and segments were compared in the condition of 95% of the target volume reached the prescribed dose. Results Compared with Pareto group, Constrained group achieved a better HI and CI. CI of PGTV and PTV1 signed statistical differences (P < 0.05). Dose of OARs in Constrained group were all lower than those in Pareto group except Optical-l and lens-l. The differences of spinal cord prv dose and V₃₀ of Parotid-r between two groups was significant (P < 0.05) while the differences of monitor units and segments between two groups was not significant (P > 0.05). Conclusion The length of middle turbinate is negatively correlated with the occurrence and severity of CMS. There is no significant correlation between the degree of curling and the occurrence of CMS, but patients with lower degree of curling of middle turbinate may have more serious CMS.

Objective To investigate the application value of pancreaticojejunostomy with double-layer continuous suture in total laparoscopic pancreaticoduodenectomy (TLPD).Methods The retrospective crosssectional study was conducted.The clinicopathological data of 21 patients who underwent TLPD with pancreaticojejunostomy using double-layer continuous suture in the Second Hospital of Jilin University between January and December 2017 were collected.The anastomosis used Child method,and pancreaticojejunostomy,choledochojejunostomy and gastroenteric anastomosis in turn were done.Observation indicators:(1) surgical and postoperative recovery;(2) postoperative pathological examination;(3) follow-up and survival situations.Follow-up using outpatient examination and telephone interview was performed to detect postoperative survival and tumor recurrence or metastasis up to February 2018.Measurement data with normal distribution were represented as x±s.Measurement data with skewed distribution were described as M (P25,P75).Results (1) Surgical and postoperative recovery:21 patients underwent successful TLPD with pancreaticojejunostomy with double-layer continuous suture.The operation time,time of pancreaticojejunostomy and volume of intraoperative blood loss were respectively (352±25)minutes,(46±8)minutes and (168±34) mL.There was no intraoperative blood transfusion.The time of postoperative abdominal drainage-tube removal was (10.1±4.4)days.Of 21 patients,12 were complicated with biochemical fistula,and 3 with grading B of pancreatic fistula (pancreatic duct in type Ⅱ),and they were improved by inhibiting pancreatic secretion and drainage patency.There was no occurrence of biliary fistula,chylous fistula,postoperative bleeding,abdominal infection and delayed gastric emptying.The duration of postoperative hospital stay of 21 patients was (11.3± 2.0) days.(2) Postoperative pathological examination:surgical margins of 21 patients were negative.The pathological type:8,6,4,2 and 1 patients were diagnosed as distal bile duct cancer,ampulla cancer,duodenal papilla and duodenal cancer,pancreatic head cancer and neuroendocrine cancer of ampulla,respectively.(3) Follow-up and survival situations:21 patients were followed up for 3-12 months,with a median time of 7 months.During the follow-up,all the patients survived,and there was no tumor recurrence and metastasis.Conclusion Pancreaticojejunostomy with double-layer continuous suture is safe and feasible for TLPD,with advantages of exact anastomosis effect and good application value.

To develop a medication reminder based on Android platform, which can be used to set up personalized reminders quickly and record the patient' s medication time-stamp and related information. In addition, the effect of using the reminder on medication compliance was studied. 14 subjects participated in the evaluation of medica-tion compliance. The differences of dosage and medication rate between the group using and without using reminder were investigated. The dosage and medication rate were got by the pill counting. The Wilcoxon matched -pairs signed rank test showed that the dosage and the medication rate of the group using reminder were higher than that without using reminder significantly(Z= -2. 93, P =0. 003 ). The results demonstrated that the use of the re-minder can improve the medication dose and rate significantly,indicate that the reminder might be a new technical support for clinical research on medication compliance, and also might reduce the workload for medical staff and patients.

Objective To investigate the effect of humidex combined with mean temperature and relative humidity on the incidence of bacillary dysentery in Hefei. Methods Daily counts of bacillary dysentery cases and weather data in Hefei were collected from January 1, 2006 to December 31, 2013. Then, the humidex was calculated from temperature and relative humidity. A Poisson generalized linear regression combined with distributed lag non-linear model was applied to analyze the relationship between humidex and the incidence of bacillary dysentery, after adjusting for long-term and seasonal trends, day of week and other weather confounders. Stratified analyses by gender, age and address were also conducted. Results The risk of bacillary dysentery increased with the rise of humidex. The adverse effect of high humidex (90 percentile of humidex) appeared in 2- days lag and it was the largest at 4-days lag (RR=1.063, 95%CI:1.037-1.090). Subgroup analyses indicated that all groups were affected by high humidex at lag 2-5 days. Conclusion High humidex could significantly increase the risk of bacillary dysentery, and the lagged effects were observed.