Effects of nucleon resonances on η\eta photoproduction off the neutron reexamined

We investigate $\eta$ photoproduction off the neutron target, i.e., $\gamma n \to \eta n$, employing an effective Lagrangian method combining with a Regge approach. As a background, we consider nucleon exchange in the $s$-channel diagram and $\rho$- and $\omega$-meson Regge trajectories in the $t$ channel. The role of nucleon resonances given in the Review of Particle Data Group in the range of $W \approx 1500 - 2100$ MeV and the narrow nucleon resonance $N(1685,1/2^+)$ is extensively studied. The numerical results of the total and differential cross sections, double polarization observable $E$, and helicity-dependent cross sections $\sigma_{1/2}$, $\sigma_{3/2}$ are found to be in qualitative agreement with the recent A2 experimental data. The predictions of the beam asymmetry are also given.Comment: 12 pages, 6 figure

Improved blue light-emitting polymeric device by the tuning of drift mobility and charge balance

We have prepared blue polymer-small molecule hybrid electroluminescence devices with improved efficiency and lower driving voltage by the statistical design method. Analysis of time-of-flight measurement shows that amorphous small molecule hole-transporter blended with a blue light-emitting polymer increases the field-dependent hole mobility, with transition from nondispersive to dispersive transport induced by the charge-trapping effect. Moreover, at the electroluminescent devices with different electron injection/transport layer ~LiF/Al, LiF/Ca/Al, and Alq3 /LiF/Al), efficiency was further increased. We have analyzed that carrier mobility of a multilayered device can also be controlled by the change of electron injection and transport layers. We find that structural design and matching overall charge balance is an essential factor to improve both the operating voltage and efficiency of existing blue polymer devices

Association between physical activity and episodic memory and the moderating effects of the apolipoprotein E ε4 allele and age

BackgroundAn abundance of evidence indicates that physical activity may protect against Alzheimer’s disease (AD) and related cognitive decline. However, little is known about the association between physical activity and AD-related cognitive decline according to age and the apolipoprotein E (APOE) ε4 allele (APOE4) as major risk factors. Therefore, we examined whether age and APOE4 status modulate the effects of physical activity on episodic memory as AD-related cognition in non-demented older adults.MethodsWe enrolled 196 adults aged between 65 and 90 years, with no dementia. All participants underwent comprehensive clinical assessments including physical activity evaluation and APOE genotyping. The AD-related cognitive domain was assessed by the episodic memory, as the earliest cognitive change in AD, and non-memory cognition for comparative purposes. Overall cognition was assessed by the total score (TS) of the Consortium to Establish a Registry for Alzheimer’s Disease neuropsychological battery.ResultsWe found significant physical activity × age and physical activity × APOE4 interaction effects on episodic memory. Subgroup analyses indicated that an association between physical activity and increased episodic memory was apparent only in subjects aged > 70 years, and in APOE4-positive subjects.ConclusionOur findings suggest that physical activity has beneficial effects on episodic memory, as an AD-related cognitive domain, in individuals aged > 70 years and in APOE4-positive individuals. Physicians should take age and APOE4 status account into when recommending physical activity to prevent AD-related cognitive decline

Microscopic evidence of strong interactions between chemical vapor deposited 2D MoS2 film and SiO2 growth template

Two-dimensional MoS2 film can grow on oxide substrates including Al2O3 and SiO2. However, it cannot grow usually on non-oxide substrates such as a bare Si wafer using chemical vapor deposition. To address this issue, we prepared as-synthesized and transferred MoS2 (AS-MoS2 and TR-MoS2) films on SiO2/Si substrates and studied the effect of the SiO2 layer on the atomic and electronic structure of the MoS2 films using spherical aberration-corrected scanning transition electron microscopy (STEM) and electron energy loss spectroscopy (EELS). The interlayer distance between MoS2 layers film showed a change at the AS-MoS2/SiO2 interface, which is attributed to the formation of S–O chemical bonding at the interface, whereas the TR-MoS2/SiO2 interface showed only van der Waals interactions. Through STEM and EELS studies, we confirmed that there exists a bonding state in addition to the van der Waals force, which is the dominant interaction between MoS2 and SiO2. The formation of S–O bonding at the AS-MoS2/SiO2 interface layer suggests that the sulfur atoms at the termination layer in the MoS2 films are bonded to the oxygen atoms of the SiO2 layer during chemical vapor deposition. Our results indicate that the S–O bonding feature promotes the growth of MoS2 thin films on oxide growth templates.This work was fnancially supported by National Research Foundation of Korea (NRF) funded by the Ministry of Science and ICT (2018M3D1A1058793, 2019M3E6A1103818, 2020M2D8A206983011, 2021R1A2B5B03001851). The Inter-University Semiconductor Research Center and Institute of Engineering Research at Seoul National University provided research facilities for this work

Hysteroscopic Resection of the Vaginal Septum in Uterus Didelphys with Obstructed Hemivagina: A Case Report

Uterus didelphys with obstructed hemivagina and ipsilateral renal agenesis is a rare congenital anomaly. Excision of the obstructed vaginal septum is the treatment of choice for symptom relief and the preservation of reproductive capability. A 14-yr-old girl complained of persistent vaginal spotting following each menstruation. Pelvic magnetic resonance imaging revealed a uterus didelphys with left hematocolpos and ipsilateral renal agenesis. Instead of conventional transvaginal excision of the vaginal septum, we used hysteroscopic excision under transabdominal ultrasonographic guidance to preserve the integrity of the hymen. The postoperative course was uneventful, and clinical symptoms were completely resolved after this intervention. Resectoscopic excision of the vaginal septum was found to be easy, safe, effective, and appropriate for young women as it preserved hymen integrity. We believe that this is the first Korean report on the use of a hysteroscopy for vaginal septum resection in a patient with uterus didelphys with obstructed hemivagina