The fast development of nanomaterials supplies the theory basis and technique support to solve the problems in the field of food safety detection. By the combination with the functional nanomaterials and traditional detection methods, novel detection methods with higher sensitivity, high throughput and rapid detection time could be developed, which attracted much attention in the detection of microorganism, chemical residues and biological toxins. In this article, we summarize the recent progress of the application of the main functional nanomaterials in food safety.

Objective To study the relationship of the university students' procrastination and big five personality factors.Methods 461 university students were assessed by the simple edition of tuckman procrastination scale(TPS) and the big five personality inventory short form(NEO-FFI).Results TPS score of the student was (48.51 ± 7.66).There were 89.4% students respectively had different level of procrastination behavior.There were no significant differences in university students by the gender(47.95 ±7.84 vs 48.95 ± 7.43 ) ,whether one-child students(48.64 ± 7.49 vs 48.45 ± 7.81 ) and grades.There were significant positive correlation between procrastination and the personality factor of neuroticism( r=0.235, P＜0.01 ) and significant negative correlation with extraversion ( r=-0.180, P ＜ 0.01 ) and conscientiousness ( r =-0.198, P ＜ 0.01 ).The big five personality factors of neuroticism,extraversion and conscientiousness could explain the 14.0% variation of procrastination of university students.Conclusion Procrastination is a very common phenomenon in the university students.The students with higher neuroticism, lower extraversion and conscientiousness of big five personality have more procrastination behavior.

AIM: To explore the feasibility of direct separat and selective enlargement of the bone marrow-derived liver stem cells (BDLSC) from bone marrow cells with a culture system containing cholestatic serum in vitro . METHODS: Bone marrow cells of rats were cultured with selective media containing 2%, 5%, 7% and 10% cholestatic rat serum, respectively. The BDLSC were then induced to proliferate with the addition of hepatocyte growth factor (HGF) on the firth day. BDLSC were characterized using immunocytochemistry and RT-PCR for lineage markers, glycogen staining and urea synthetic assay for functions 2 weeks later. RESULTS: Bone marrow cells were unble to form colony in the presence of 2% cholestatic serum and apopotosis appeared gradually in 7% or 10% cholestatic serum. The BDLSC survived in the medium containing 5% cholestatic serum while the other types of cells did not. The survival cells proliferated with a high speed during the second week and then formed hepatocyte-like colony-forming units (H-CFU). Cells in the H-CFU expressed the characteristic proteins of fetal hepatocytes. Furthermore, they had glycogen storage and urea synthesis functions, two of the critical features of hepatocytes. CONCLUSION: The selective micro-environment effectively selected BDLSC from the bone marrow cell, and will be a new way to provide an abundant source of donor hepatocytes for clinical cell therapy.

Objective:To evaluate the efficacy of dual-tuberosity locking plate for the treatment of proximal humeral fractures.Methods:This study retrospectively analyzed data of patients with proximal humeral fractures treated with a new locking plate from July 2017 to July 2019. Finally, 19 eligible patients were included, including 12 females and 7 males, with an average age of 64.0±12.8 years (range, 32-85 years). According to the Neer classification of proximal humeral fractures, 1 case was two-part fractures, 9 cases three-part fractures and 9 cases four-part fractures. Among them, 9 cases combined with greater and lesser tuberosities fractures and 10 cases with isolated greater tuberosity fractures. Constant-Murley and disabilities of the arm shoulder and hand (DASH) scores, the change of neck-shaft angle, the change of humeral head height, tuberosity consolidation and other complications were recorded at the latest follow-up.Results:The mean follow-up time was 16.1 months (range, 12-18 months). All fractures were healed within follow-up period. Mean Constant-Murley score was 84.2±11.0 (range, 55-98), DASH score was 19.4±11.6 (range, 2.3-47.8) and VAS was 1.6±1.3 (range, 0-4) at the latest follow-up. As for the radiographic results, 19 patients had a mean neck-stem angle of 141.9°±9.8° (range, 132.17°-162.66°) on the first day after surgery, and a mean humeral head height of 18.0±5.9 mm (range, 7.45-27.12 mm). The mean neck-stem angle was 148.6°±7.5° (range, 132.70°-159.39°) and the mean humeral head height was 17.4± 5.5 mm (range, 5.02-27.31 mm) at the latest follow-up. The average change of neck-stem angle was 3.29° (range, 0.68°-33.10°), and mean change of humeral head height was 0.68 mm (range, 1.32-6.56 mm). No fractures developed greater or lesser tuberosity absorption or malunion, but 4 cases suffered loss of fixation and 1 developed primary intra-articular screw penetration as well as wound infection.Conclusion:In the open reduction and internal fixation of the proximal humeral fractures, the new locking plate can fix greater and lesser tuberosity fractures simultaneously, which helps reduce their displacement and deformity of tuberosities. By given that, satisfactory radiographic outcomes and shoulder functions can be obtained.

Objective:To investigate the efficacy of an anterolateral femoral chimeric perforator flap combined with vancomycin-loaded calcium sulfate in the treatment of chronic infection after internal fixation of calf fracture with soft tissue defects.Methods:Retrospectively analyzed were the data of 16 patients with chronic infection combined with extensive soft tissue defects after internal fixation of calf fracture who had been admitted to Department of Orthopedics, Shenzhen Hospital Affiliated to Peking University from September 2008 to November 2020. There were 11 males and 5 females, aged from 16 to 62 years (average, 37 years). Infection sites: the upper tibia in 4 cases, the middle and lower tibia in 10 cases, and the middle fibula in 2 cases. According to the Cierny-Mader classification, all patients were anatomical type III and by the host classification, there were 14 cases of type B and 2 cases of type C type. The areas of soft tissue defects ranged from 6 cm × 4 cm to 23 cm × 14 cm. All patients were treated by transplantation of an anterolateral thigh chimeric perforator flap combined with vancomycin-loaded calcium sulfate therapy. At the last follow-up, the curative efficacy was evaluated according to the Paley fracture union scoring.Results:All patients were followed up for 8 to 24 months (mean, 16 months). Complete flap survival was achieved in 15 flaps and partial survival in one. According to the Paley fracture union scoring at the last follow-up, the curative efficacy was evaluated as excellent in 15 cases and as good in one. Both the grafted artificial bone and the tibia and fibula achieved bone union after 6 to 12 months (mean, 8.9 months). Infection with chronic sinus tract pus recurred in one case at post-operative one year. After re-debridement, the infection was controlled and the wound healed. The plate internal fixation was replaced by the unilateral or annular external fixator in 14 patients and retained in 2 patients. The lengths of the bone defects averaged 2.4 cm and the time for the external fixation 10.5 months (from 8 to 14 months).Conclusion:In the treatment of chronic infection after internal fixation of calf fracture with extensive soft tissue defects, the efficacy of an anterolateral femoral chimeric perforator flap combined with vancomycin-loaded calcium sulfate is satisfactory, because the flap can fully cover the bone and soft tissue defects while the vancomycin-loaded calcium sulfate can effectively control the infection.

Objective To analyze the immunophenotypic characteristics of the patients with minimal residual disease (MRD) positive acute B lymphocytic leukemia (B-ALL). Methods The leukemia-associated immunophenotype (LAIP) of 106 cases with MRD positive B-ALL from Department of Hematology, Tianjin KingMed Diagnois Center between June 2014 and January 2016 were retrospectively analyzed. CD10, CD13/CD33, CD19, CD38, CD58, CD45 and other antibodies were used to analyze the MRD of B-ALL. Results All the patients were positive for CD19. CD34 was negatively or weakly positive expressed in 27 cases (25.4％). CD10 was negatively or weakly positive expressed in 23 cases (21.7％). CD10 was strongly positive in 24 cases (22.6％). Totally, CD10 was weakly or strongly expressed in 47 cases (44.3％). CD58 was strongly positive in 98 cases (92.5％). CD13/CD33 was positively or weakly positive expressed in 64 cases (60.4％). CD38 was negative or weakly expressed in 33 cases (31.1％). CD45 was negative in 21 cases (19.8％). 15 cases (14.1％) were positive for 6 types of LAIP; 30 (28.3％) cases were positive for 5 types of LAIP; 42 (39.6％) cases were positive for 4 types of LAIP; 13 (12.3％) cases were positive for 3 types of LAIP;5 cases (4.7％) were positive for 2 types of LAIP; only one case (0.9％) was positive for 1 type of LAIP. Conclusion The combination of CD58, CD13/CD33, CD10, CD38 and CD34 antibodies can distinguish the neoplastic blast/immature B lymphocytes from progenitor B cells. This strategy has a high accuracy for the judgement of MRD in B-ALL.