Objective To investigate the effects of group identification on death anxiety among military medical students and the chain mediating effects of self-esteem and collective self-esteem.Methods Cluster sampling was conducted to survey the students in a military medical university in July,2021,and finally survey data from 360 participants were collected through WeChat Mini Program,Questionnaire Star.The Questionnaires included Templer Death Anxiety Scale(T-DAS),Organizational Identification Questionnaire,Rosenberg Self-Esteem Scale-Revised(RSES-R),Collective Self-Esteem Scale and a self-designed general information questionnaire.Results ①The score of death anxiety in the participants ranged from 1.00 to 4.33(M=2.60).②The scores of group identification,self-esteem and collective self-esteem were negatively correlated with death anxiety(r=-0.56～-0.21,P＜0.01).Significantly positive correlations were observed in any 2 scores among the above 3 scores(r=0.42～0.68,P＜0.01).③ Group identification significantly negatively predicted death anxiety(b=-0.21,SE=0.02,P＜0.001).④ There were 3 mediation effects between group identification and death anxiety:group identification→self-esteem→death anxiety,group identification→ collective self-esteem→ death anxiety,group identification→ self-esteem→collective self-esteem→death anxiety,with a total indirect effect of-017.Conclusion Group identification can negatively predict death anxiety among military medical students,and self-esteem and collective self-esteem play a chain mediating role between them.

Objective To explore the mediating effect of facial emotion recognition on prosocial behavior of medical students in mask-obscured scenes.Methods Fifty-three medical students from a medical university in Chongqing were enrolled from July to September 2023 to complete the facial emotion recognition task,the dictator gaming task and the state empathy test.Spearman correlation analysis was used to examine the correlation between mask wearing and state empathy,trait empathy and prosocial behaviours,and the PROCESS procedure was used to test the mediation of state empathy and the moderating effect of mask wearing or not.Results ①mask wearing,state empathy and prosocial behaviour were significantly correlated(P＜0.01);② State empathy exerted mediated effect between facial emotion recognition and prosocial behavior,with the largest effect size(47％)for the relative mediating effect of sadness;③The interaction terms of facial emotion recognition and mask wearing had a significant effect on state empathy(P＜0.05).Conclusion Facial emotion recognition can influence prosocial behavior directly and also exert indirect effect on prosocial behavior through state empathy.Compared to the condition without mask wearing,mask wearing can significantly facilitate the effect of happy,sad and neutral emotions on state empathy.

Most solid tumors suffer from inadequate blood perfusion and oxygenation, leading to a hypoxic microenvironment that accelerates tumor progression and adversely impacts prognosis. Thus, improving oxygenation in tumor tissues is crucial for enhancing the sensitivity and efficacy of tumor therapy. Hemoglobin-based oxygen carriers (HBOCs), as a type of oxygen-carrying nanoparticles, can not only carry and release oxygen but also reach the small blood vessels of obstructive microcirculation to deliver oxygen for anoxic tissues and organs, which are difficult for normal red blood cells to pass through. Studies have demonstrated that the application of HBOCs as a potential nanoscale efficient oxygen carrier in tumor therapy can enhance tissue oxygenation and hold great promise for applications in tumor therapy.This review summarizes the impact of hypoxia in tumors and highlights the progress and potential mechanisms of using HBOCs in tumor radiotherapy, chemotherapy, new kinetic therapy and immunotherapy.

【Objective】 To prepare microneedles(MNs) loaded with platelet-rich plasma lysate (PL) using Carboxymethyl chitosan (CMCS), and explore the prospect of PL MNs in the treatment of diabetic wounds. 【Methods】 CMCS was used as the basic material, and an appropriate amount of polyvinylpyrrolidone (PVPK-60) was added to prepare needle materials of different concentrations, and the optimal concentration was determined by investigating the needle formation rate, morphological characteristics and mechanical properties, and the growth factor activity in PL MNs was investigated. The diabetic mice were randomly divided into four groups after the back wound was made, the control group did not do any treatment, the PL smear group was treated with PL smearing, the blank MNs group was treated with MNs without PL, and the PL MNs group was treated with PL microneedles. The effect of PL MNs in wound healing in diabetic mice was evaluated through body observation, H&E staining and immunohistochemistry results. 【Results】 When PVPK60 was 40 mg/mL, the needle formation rate was 100%, the array was complete, the needle body was full, and the needle was sharp. According to the results of mechanical-displacement curve and weight pressure change experiment, the prepared PL MNs have good mechanical strength. The results of growth factor analysis indicated that the content of vascular endothelial growth factor (VEGF) in PL was (625±35) pg/mL, and the content of platelet-derived growth factor-BB (PDGF-BB) was (18 741±1 287) pg/mL. After making the MNs, the VEGF content was (183±2) pg/mL, and the PDGF-BB content was (8049±1157) pg/mL. Although the concentration of growth factors decreased, growth factor activity was still preserved.The results of wound healing experiments in diabetic mice showed that the PL MNs group had better healing, and the wound healing rate was different from that of three groups (P<0.01). The results of H&E staining showed that the PL MNs group had fewer inflammatory cell infiltrates and bleeding spots. The number of fibroblasts and new microvascular in the control group was worse than that in the PL MNs group and the PL smear group. The results of immunohistochemistry indicated that the expression of pro-inflammatory factor IL-6 decreased, while anti-inflammatory factor TGF-β and angiogenesis index CD31 increased in the PL MNs group, which were significantly different from those in the other three groups (P<0.01). 【Conclusion】 The PL MNs prepared in this experiment have good mechanical properties, which has a positive effect on the wound healing of diabetic mice, and provides a new idea for diabetic wound healing.

【Objective】 To investigate the application prospect of platelet-rich plasma lysate (PL) microneedles in the treatment of wound healing by optimizing the preparation process and evaluating the activity of platelet growth factor. 【Methods】 Firstly, hyaluronic acid (HA) was used as needle matrix material, and the concentration of HA was preliminarily determined by investigating the fluidity of HA solution, shape of needle, pressure change performance and puncture performance.Combined with the results of HA dissolution in PL, mechanical properties of PL microneedles and skin puncture, the preparation process of platelet-rich plasma lysis microneedles (PLMN) was optimized to investigate the growth factor activity of PLMN and evaluate the effect of PLMN on wound healing in rats. 【Results】 When the concentration of HA was 30 mg/mL, the solution had good fluidity.The HA microneedles could pierce three layers of sealing film, with the puncture rate at 70%, and the solution had good mechanical properties.When HA was dissolved in PL at a concentration of 30 mg/mL at 4℃, the solution had no crystallization and was with good fluidity.The prepared PLMN showed good needle shape and no bending under HD microscope and scanning electron microscope.In vitro transdermal simulation results showed that PLMN could penetrate 4 layers of sealing membrane, and the puncture rate of the first three layers was more than 85%.In vivo lysis experiment showed that PLMNs could be completely dissolved within 10 min after being inserted into the body.Forty minutes later, the micropores left after the insertion of the microneedle were almost closed, without redness, swelling, erythema and other adverse reactions.In vitro and in vivo transdermal experiments showed that clear blue holes were visible after PLMNs penetrated the skin stain, indicating that the microneedles could pierce the skin barrier.Growth factor detection results showed that the content of platelet-derived growth factor (PDGF-BB) and transforming growth factor (TGFβ1) in platelet lysate were (17.67±1.23) ng/mL and (105.95±2.16) ng/mL, respectively.After PLMNs were prepared and stored at room temperature for 1 week, the content of PDGF-BB(ng/mL) and TGFβ1(ng/mL) were 15.48±2.12 and 56.26±1.53, respectively.Compared with PL(vs 17.67±1.23 and 105.95±2.16), the content of PDGF-BB and TGFβ1 decreased, but still maintained the activity of growth factors.The results of wound healing experiment in rats showed that the wound healing rate (%) of PLMN group on the third day was significantly different from that of the control group(52.51±6.15 vs 33.31±3.60, P<0.05). 【Conclusion】 The PLMN prepared in this experiment has good mechanical properties and can successfully pierce the skin cuticle.It can also maintain the activity of growth factors, and has a good effect on wound healing in rats, which provides a new idea for minimally invasive treatment in the field of tissue repair.