Controlling of the surface energy of the gate dielectric in organic field-effect transistors by polymer blend

In this letter, we demonstrate that by blending insulating polymers, one can fabricate an insulating layer with controllable surface energy for organic field-effect transistors. As a model system, we used copper phthalocyanine evaporated on layers of polymethyl metacrylate blended with polystyrene with different blending ratios and measured the field-effect mobility in transistors. We show that the highest field-effect mobility is achieved for identical surface energies of the dielectric and the semiconductor. This simple technique demonstrates the viability of using the blends of insulating polymers to systematically control the surface energy of the gate dielectric toward achieving better performances

Self-control moderates the association between perceived severity of Coronavirus Disease 2019 (COVID-19) and mental health problems among the Chinese public

Coronavirus disease 2019 (COVID-19) has caused thousands of deaths in China. Prior research suggests that individuals’ perceived severity of COVID-19 is related to a range of negative emotional and behavioral reactions among the Chinese public. However, scant research has examined the underlying mechanisms. Drawing upon the risk-resilience model, this study proposes that self-control, as a resilient factor, would potentially moderate the association between perceived severity of COVID-19 and mental health problems. Data from a national survey was used to examine this idea. Participants were 4607 citizens from 31 regions in China (Mage = 23.71 years, 72.5% female) who completed a national survey at the beginning of February 2020. Results of hierarchical regression showed that after controlling for a number of demographic variables, perceived severity of COVID-19 and self-control were positively and negatively related to mental health problems, respectively. More importantly, self-control moderated the “perceived severity of COVID-19–mental health problems” association, with this link attenuating as the levels of self-control increased. These findings suggest that compared to those with high self-control, individuals with low self-control are more vulnerable and are more in need of psychological aids to maintain mental health in the encounter of the COVID-19 outbreak. Practically, enhancing individuals’ self-control ability might be a promising way to improve individuals’ mental health during the early period of the COVID-19 outbreak

Experimental Realization of Weyl Exceptional Rings in a Synthetic Three-Dimensional Non-Hermitian Phononic Crystal

Weyl points (WPs) are isolated degeneracies carrying quantized topological charges, and are therefore robust against Hermitian perturbations. WPs are predicted to spread to the Weyl exceptional rings (WERs) in the presence of non-Hermiticity. Here, we use a one-dimensional (1D) Aubry-Andre-Harper (AAH) model to construct a Weyl semimetal in a 3D parameter space comprised of one reciprocal dimension and two synthetic dimensions. The inclusion of non-Hermiticity in the form of gain and loss produces a WER. The topology of the WER is characterized by both its topological charge and non-Hermitian winding numbers. The WER is experimentally observed in a 1D phononic crystal with the non-Hermiticity introduced by active acoustic components. In addition, Fermi arcs are observed to survive the presence of non-Hermitian effect. We envision our findings to pave the way for studying the high-dimensional non-Hermitian topological physics in acoustics.Comment: 14 pages, 5 figure

Role of miR-1 and miR-133a in myocardial ischemic postconditioning

<p>Abstract</p> <p>Background</p> <p>Ischemic postconditioning (IPost) has aroused much attention since 2003 when it was firstly reported. The role of microRNAs (miRNAs or miRs) in IPost has rarely been reported. The present study was undertaken to investigate whether miRNAs were involved in the protective effect of IPost against myocardial ischemia-reperfusion (IR) injury and the probable mechanisms involved.</p> <p>Methods</p> <p>Thirty SD rats weighing 250-300 g were equally randomized to three groups: Control group, where the rats were treated with thoracotomy only; IR group, where the rats were treated with ischemia for 60 min and reperfusion for 180 min; and IPost group, where the rats were treated with 3 cycles of transient IR just before reperfusion. The extent of myocardial infarction, LDH and CK activities were measured immediately after treatment. Myocardial apoptosis was detected by TUNEL assay. The myocardial tissue was collected after IR or IPost stimulation to evaluate the miRNAs expression level by miRNA-microarray and quantitative real-time RT-PCR. Real-time PCR was conducted to identify changes in mRNA expression of apoptosis-related genes such as Bcl-2, Bax and Caspase-9 (CASP9), and Western blot was used to compare the protein expression level of CASP9 in the three groups. The miRNA mimics and anti-miRNA oligonucleotides (AMO) were transferred into the cultured neonatal cardiomyocytes and myocardium before they were treated with IR. The effect of miRNAs on apoptosis was determined by flow cytometry and TUNEL assay. CASP9, as one of the candidate target of miR-133a, was compared during IR after the miR-133a mimic or AMO-133a was transferred into the myocardium.</p> <p>Results</p> <p>IPost reduced the IR-induced infarct size of the left ventricle, and decreased CK and LDH levels. TUNEL assay showed that myocardial apoptosis was attenuated by IPost compared with IR. MiRNA-microarray and RT-PCR showed that myocardial-specific miR-1 and miR-133a were down-regulated by IR, and up-regulated by IPost compared with IR. Furthermore, IPost up-regulated the mRNA expression of Bcl-2, down-regulated that of Bax and CASP9. Western blot showed that IPost also down-regulated the CASP9 protein expression compared with IR. The results of flow cytometry and TUNEL assay showed that up-regulation of miR-1 and miR-133a decreased apoptosis of cardiomyocytes. MiR-133a mimic down-regulated CASP9 protein expression and attenuated IR-induced apoptosis.</p> <p>Conclusion</p> <p>MiRNAs are associated with the protective effect of IPost against myocardial IR injury. IPost can up-regulate miR-1 and miR-133a, and decrease apoptosis of cardiomyocyte. Myocardial-specific miR-1 and miR-133a may play an important role in IPost protection by regulating apoptosis-related genes. MiR-133a may attenuate apoptosis of myocardiocytes by targeting CASP9.</p

Developments of a 2D Position Sensitive Neutron Detector

Chinese Spallation Neutron Source (CSNS), one project of the 12th five-year-plan scheme of China, is under construction in Guangdong province. Three neutron spectrometers will be installed at the first phase of the project, where two-dimensional position sensitive thermal neutron detectors are required. Before the construction of the neutron detector, a prototype of two-dimensional 200 mmx200 mm Multi-wire Proportional Chamber (MWPC) with the flowing gas of Ar/CO2 (90/10) has been constructed and tested with the 55Fe X-Ray using part of the electronics in 2009, which showed a good performance. Following the test in 2009, the neutron detector has been constructed with the complete electronics and filled with the 6atm.3He + 2.5atm.C3H8 gas mixture in 2010. The neutron detector has been primarily tested with an Am/Be source. In this paper, some new developments of the neutron detector including the design of the high pressure chamber, the optimization of the gas purifying system and the gas filling process will be reported. The results and discussion are also presented in this paper.Comment: 5 page