Subunit vaccines are developed from the immunologically active fragments of pathogens and do not have genetic materials,which have been the center of research attention,guiding the direction of the development for new generations of vaccines.Given their safety advantages and high immunological activities,subunit vaccines play important roles in prevention of the spread of pathogenic viruses.This paper mainly introduces the research progress and applications of the subunit vaccines in common viral diseases,aiming to establish a theoretical basis for the development of the subunit vaccines on new viral diseases.

Abstract Autism spectrum disorder (ASD) is a lifelong neurodevelopmental disorder. Early life social experience assessment before symptoms of ASD might be helpful for determining the causal link between social experiences and early childhood ASD. Younger children are exposed to excessive screen time in recent years. This paper summarizes the association between screen exposure with ASD in preschool children, and proposes future research directions and provides evidencebased guidance to optimize and support children s early media experiences.

Objective To understand the clinical characteristics of traumatic brain injury (TBI) patients and provide fundamental data for reducing the incidence of TBI and improving its treatment efficacy.Methods Medical histories of TBI inpatients from January 2011 to December 2016 were collected from the TBI database of Neurosurgical Department at Tianjin Medical University General Hospital.Information including gender,age,causes of TBI,injury severity,sources of the inpatients,interval from injury to treatment,diagnosis,and treatment were analyzed retrospectively.Results A total of 2 368 TBI patients were enrolled,aged mainly 30-60 years.There were more male patients (n =1 741) than female patients (n =627) (2.78 ∶ 1),while the gender ratio was reversed among patients above 60 years old (2.09 ∶ 1) (P ＜ 0.05).Traffic accident (60.14％) remained the major cause of TBI,while the proportion of electric motorcycle accident was 17.35％,followed by fall from height (13.64％).The proportion of mild TBI patients from suburb counties was lower than that of patients from the six urban areas (P ＜ 0.05),while the proportion of heavy TBI patients from other provinces was higher than those of both urban and suburb counties (P ＜ 0.05).The average interval from injury to specialist treatment was 7.53 hours.Patients who received treatment within 3 hours had better improvement than those who were treated 3 hours after TBI (P ＜ 0.05).The main injuries were skull fracture (33.07％) and brain contusion (30.32％).A total of 783 patients (33.07％) underwent surgery,among which 693 patients received the most common procedure of craniotomy hematoma evacuation (including decompressive craniectomy).The improvement rate of patients with intracranial pressure monitoring was higher than those without intracranial pressure monitoring (P ＜ 0.05).The improvement rate of the surgery group was significantly higher than that of the non surgery group (P ＜0.05).Conclusions The ratio of elderly female TBI patients is on the rise;TBI presents an increase in traffic accidents;mild TBI patients choose to receive treatment in close hospitals while those with severe TBI choose comprehensive hospitals;and the interval from injury to treatment is long.The following strategies including improving the traffic facilities,strengthening the education of traffic safety on elderly females and pedestrians,and optimizing the TBI medical treatment process would reduce the incidence of TBI and improve the efficiency of treatment.

【Objective】 To analyze the associations between different types of video screen time and psychological behaviors of preschool children, in order to provide evidence for promoting the development of children′s mental health. 【Methods】 From February to March 2023, a total of 1 361 parents of children aged 3 - 6 years from 6 kindergartens of Lanzhou were surveyed by cluster sampling method.Parents were surveyed to obtain information about the video use, and the children′s Strengths and Difficulties questionnaire (parent version) was used to assess children′s psychological and behavioral problems. 【Results】 The rate of daily screen time exceeding standard was 36.96% (503/1 361).The screen time was mainly spent in watching TV cartoons, followed by educational APP.The detection rate of abnormal total difficulty score was 11.61% (158/1 361), and the abnormalities of peer communication (32.26%) and prosocial behavior (12.34%) were the most prominent.After adjusting for related factors by multiple Logistic regression analysis, total screen time≥2h/d (OR=1.802) was found to be a risk factor for abnormal total difficulty score; watching TV cartoons≥2h/d was a risk factor for abnormal total difficulty score (OR=2.409) and peer communication (OR=2.222); playing games≥1h/d was a risk factor for abnormal total difficulty score, emotional symptoms, conduct problems, hyperactive behavior, and abnormalities of peer communication, the differences were all statistically significant (P<0.05).However, educational APP screen time<1h/d was a protective factor for abnormal total difficulty score(OR=0.615) and prosocial behavior (OR=0.549), but educational APP screen time≥2h/d was a risk factor for conduct problems (OR=2.302), the differences were all statistically significant (P<0.05). 【Conclusions】 The screen time of preschool children in Lanzhou cannot be ignored, and there is a significant correlation between overuse and children′s psychological and behavioral problems.Parents and schools should attach importance to the parent-child and peer interaction of preschool children and strengthen the intervention of preschool children′s video behavior.

Active immunotherapy for cancer aims to treat disease by inducing effective cellular immunity and humoral immunity.Research on virus-like particles(VLPs)vaccines has made tremendous progress in recent years,dramatically reducing morbidity and mortality from some infectious diseases.VLPs are nanoparticles self-assembled from one or more structural proteins,with highly ordered repeat sequences and good immunogenicity,which can induce strong cellular immune and humoral immune responses.VLPs can overcome immunosuppressive state of tumor microenvironment,break self-tolerance,and trigger strong cytotoxic T lymphocyte activity,which is critical for both viral clearance and destruction of cancer cells.This article mainly reviews current research progress of VLPs-based cancer vaccines and potential defects of VLPs as vaccine carriers in development of cancer vaccines.

Virus-like particles(VLPs)are nanoparticles that are self-assembled from one or more structural proteins,which can be arranged in several layers or contain a lipid outer membrane.Due to the lack of genetic material,VLPs cannot infect host cells,but are highly immunogenic and can induce immune responses different from conventional inactivated vaccines.VLPs can be produced using a variety of systems including bacterial,yeast,plant,insect and mammalian cells.Compared with traditional vaccines,VLPs have incomparable advantages,so they are becoming more and more popular in the biomedical field.To date,a series of vaccine candi-dates based on VLPs have been developed for immunization and prevention of various infectious diseases.At the same time,the recent successful application of VLPs in targeted drug delivery and gene therapy has attracted attention.This paper mainly reviews the com-monly used expression systems of VLPs and the research progress of their applications.