Low-temperature crystalline lead-free piezoelectric thin films grown on 2D perovskite nanosheet for flexible electronic device applications

A monolayer of Sr2Nb3Oio(SNO)is deposited on the Pt/Ti/SiCWSi(Pt?Si)or Pt/Ti/polyimide(Pt-Pl)substrate by using the Langmuir-Blodgett method and employed as a seed-layer for the growth of a crystalline(Nai_xKx)NbO3(NKN)film at 350℃.The crystalline NKN film is grown along the[001]direction on the SNO/Pt-Si(or SNO/Pt-PI)substrate.Due to the presence of oxygen vacancies in the SNO seed-layer,the NKN film exhibits low ferroelectric properties and large leakage current.To ameliorate these properties,the SNO/Pt-Si substrate is annealed in a 50 Torr oxygen atmosphere at 300℃,which removes the oxygen vacancies.Consequently,the NKN film deposited on this substrate exhibits promising electrical properties,namely a dielectric constant of 278,dissipation factor of 1.7%,a piezoelectric 8nstant of 175 pm`V^-1,and a leakage current density of 6.47 x 10^-7 A cm^-2 at-0.2 MV crrT1.Similar electrical properties are obtained from the NKN film grown on the flexible SNO/Pt-PI substrate at 350°C.Hence,the NKN films grown on the SNO seed-layer at 350°C can be applied to electronic devices with flexible polymer substrates.

Gender differences in adult traumatic brain injury according to the Glasgow coma scale:A multicenter descriptive study

Purpose:Patients’gender,which can be one of the most important determinants of traumatic brain injury(TBI)outcomes,is also likely to interact with many other outcome variables of TBI.This multicenter descriptive study investigated gender differences in epidemiological,clinical,treatment,mortality,and variable characteristics in adult TBI patients.Methods:The selection criteria were defined as patients who had been diagnosed with TBI and were admitted to the hospital between January 1,2016 and December 31,2018.A total of 4468 adult TBI patients were enrolled at eight University Hospitals.Based on the list of enrolled patients,the medical records of the patients were reviewed and they were registered online at each hospital.The registered patients were classified into three groups according to the Glasgow coma scale(GCS)score:mild(13-15),moderate(9-12),and severe(3-8),and the differences between men and women in each group were investigated.The risk factors of moderated and severe TBI compared to mild TBI were also investigated.Results:The study included 3075 men and 1393 women and the proportion of total males was 68.8%.Among all the TBI patients,there were significant differences between men and women in age,past history,and GCS score.While the mild and severe TBI groups showed significant differences in age,past history,and clinical symptoms,the moderate TBI group showed significant differences in age,past history,cause of justice,and diagnosis.Conclusion:To the best of our knowledge,this multicenter study is the first to focus on gender differences of adult patients with TBI in Korea.This study shows significant differences between men and women in many aspects of adult TBI.Therefore,gender differences should be strongly considered in TBI studies.

Seroepidemiology of echovirus 30 in Korean children

Background:Although aseptic meningitis associated with echovirus type 30 has emerged as a global public health concern,no data have been reported on children's immune status against echovirus type 30.The current study aimed to investigate the seropositivity among Korean children for antibodies against echovirus 30.Methods:Two hundred and fifty residual serum samples were collected at St.Paul's Hospital.Individuals were categorized by age into four groups:group 1 (3 months-2 years),group 2 (3-6 years),group 3 (7-10 years) and group 4 (11-15 years).Neutralizing antibodies against echovirus 30 were measured.Results:Seroprotective neutralizing antibodies against echovirus 30 were detected in 129 (49%) individuals.Seropositivity rates were 23%,48%,55% and 73% in groups 1-4,respectively.For antibody titers,1:256-1:512 was the highest neutralizing antibody titer range in group 2,while 1:1024-1:2048 in group 3 and 4.Among the seropositive individuals in group 3 and 4,6% and 12% had neutralizing antibody titers of 1:2048,respectively.Conclusions:The seropositivity rate increased significantly with age..The distribution of neutralizing antibody titers varied by age group,and higher ranges of neutralizing antibody titers were observed in higher age groups.These findings suggest high susceptibility to echovirus 30 infection in children younger than 2 years old.Echovirus 30 infection in childhood may have contributed to increased neutralizing antibody titers with age.