Collaborative session management in distributed engineering design and analysis environment

Master'sMASTER OF ENGINEERIN

Disorder induced field effect transistor in bilayer and trilayer graphene

We propose use of disorder to produce a field effect transistor (FET) in biased bilayer and trilayer graphene. Modulation of the bias voltage can produce large variations in the conductance when the disorder's effects are confined to only one of the graphene layers. This effect is based on the bias voltage's ability to select which of the graphene layers carries current, and is not tied to the presence of a gap in the density of states. In particular, we demonstrate this effect in models of gapless ABA-stacked trilayer graphene, gapped ABC-stacked trilayer graphene, and gapped bilayer graphene.Comment: 21 pages, 7 figure

Tanshinone IIA mitigates peritoneal fibrosis by inhibiting EMT via regulation of TGF-β/smad pathway

Purpose: To explore the effects of tanshinone IIA (T-IIA) on Dianeal-N PD-4 (PDF)-induced expression of fibrogenic cytokines in human peritoneal mesothelial cells (HPMCs), and to elucidate the mechanisms of action involved. Methods: Seven groups of HPMCs were used in the study: control group, PDF group, T-IIA group, LY364947 group, and 2 transforming growth factor-β (TGF-β) groups (TGF-β+ 50 μM T-IIA and TGF-β+ 100 μM T- IIA). The expression levels of mRNA and protein of TGF-β, smad2, smad7, α-smooth muscle actin(α-SMA), fibronectin, collagen І, E-cadherin, N-cadherin, matrix metalloprotein-2(MMP-2), and MMP-9 in the various groups were determined by reverse transcription-polymerase chain reaction (RTPCR) and Western blotting as appropriate. Results: The expressions of α-SMA, fibronectin, collagen І, TGF-β and smad2 were significantly upregulated in HPMCs by PDF treatment, but smad7 was down-regulated, relative to the control group (p < 0.01).These PDF-induced effects were reversed by T-IIA (p < 0.05). Inhibition of TGF-β/smad pathway by LY364947 treatment led to significant decrease in the expressions of fibrosis-related proteins, when compared with PDF group (p < 0.05). TGF-β treatment also produced numerous spindleshaped HPMCs characteristic of epithelial-mesenchymal transition (EMT). However, this morphological transition was alleviated, and the expression levels of EMT-related proteins were significantly downregulated by exposure to the two doses of T-IIA (p < 0.05). Conclusion: Tanshinone IIA inhibits EMT in HPMCs by regulating TGF-β/smad pathway, thus mitigating peritoneal fibrosis. Therefore, T-IIA has promising potential as a new drug for the treatment of peritoneal dialysis (PD)-induced fibrosis. Keywords: Peritoneal dialysis, Peritoneal fibrosis, Tanshinone IIA, Epithelial-mesenchymal transitio

Improved Charge Injection and Transport of Light-Emitting Diodes Based on Two-Dimensional Materials

Light-emitting diodes (LEDs) are considered to be the most promising energy-saving technology for future lighting and display. Two-dimensional (2D) materials, a class of materials comprised of monolayer or few layers of atoms (or unit cells), have attracted much attention in recent years, due to their unique physical and chemical properties. Here, we summarize the recent advances on the applications of 2D materials for improving the performance of LEDs, including organic light emitting diodes (OLEDs), quantum dot light emitting diodes (QLEDs) and perovskite light emitting diodes (PeLEDs), using organic films, quantum dots and perovskite films as emission layers (EMLs), respectively. Two dimensional materials, including graphene and its derivatives and transition metal dichalcogenides (TMDs), can be employed as interlayers and dopant in composite functional layers for high-efficiency LEDs, suggesting the extensive application in LEDs. The functions of 2D materials used in LEDs include the improved work function, effective electron blocking, suppressed exciton quenching and reduced surface roughness. The potential application of 2D materials in PeLEDs is also presented and analyzed

Effects of Charge Transport Materials on Blue Fluorescent Organic Light-Emitting Diodes with a Host-Dopant System

High efficiency blue fluorescent organic light-emitting diodes (OLEDs), based on 1,3-bis(carbazol-9-yl)benzene (mCP) doped with 4,4’-bis(9-ethyl-3-carbazovinylene)-1,1’-biphenyl (BCzVBi), were fabricated using four different hole transport layers (HTLs) and two different electron transport layers (ETLs). Fixing the electron transport material TPBi, four hole transport materials, including 1,1-Bis[(di-4-tolylamino)phenyl]cyclohexane (TAPC), N,N’-Di(1-naphthyl)-N,N’-diphenyl-(1,1’-biphenyl)-4’-diamine(NPB), 4,4’-Bis(N-carbazolyl)-1,1,-biphenyl (CBP) and molybdenum trioxide (MoO3), were selected to be HTLs, and the blue OLED with TAPC HTL exhibited a maximum luminance of 2955 cd/m2 and current efficiency (CE) of 5.75 cd/A at 50 mA/cm2, which are 68% and 62% higher, respectively, than those of the minimum values found in the device with MoO3 HTL. Fixing the hole transport material TAPC, the replacement of TPBi ETL with Bphen ETL can further improve the performance of the device, in which the maximum luminance can reach 3640 cd/m2 at 50 mA/cm2, which is 23% higher than that of the TPBi device. Furthermore, the lifetime of the device is also optimized by the change of ETL. These results indicate that the carrier mobility of transport materials and energy level alignment of different functional layers play important roles in the performance of the blue OLEDs. The findings suggest that selecting well-matched electron and hole transport materials is essential and beneficial for the device engineering of high-efficiency blue OLEDs

Improved Efficiency of Perovskite Light-Emitting Diodes Using a Three-Step Spin-Coated CH3NH3PbBr3 Emitter and a PEDOT:PSS/MoO3-Ammonia Composite Hole Transport Layer

High efficiency perovskite light-emitting diodes (PeLEDs) using PEDOT:PSS/MoO3-ammonia composite hole transport layers (HTLs) with different MoO3-ammonia ratios were prepared and characterized. For PeLEDs with one-step spin-coated CH3NH3PbBr3 emitter, an optimal MoO3-ammonia volume ratio (0.02) in PEDOT:PSS/MoO3-ammonia composite HTL presented a maximum luminance of 1082 cd/m2 and maximum current efficiency of 0.7 cd/A, which are 82% and 94% higher than those of the control device using pure PEDOT:PSS HTL respectively. It can be explained by that the optimized amount of MoO3-ammonia in the composite HTLs cannot only facilitate hole injection into CH3NH3PbBr3 through reducing the contact barrier, but also suppress the exciton quenching at the HTL/CH3NH3PbBr3 interface. Three-step spin coating method was further used to obtain uniform and dense CH3NH3PbBr3 films, which lead to a maximum luminance of 5044 cd/m2 and maximum current efficiency of 3.12 cd/A, showing enhancement of 750% and 767% compared with the control device respectively. The significantly improved efficiency of PeLEDs using three-step spin-coated CH3NH3PbBr3 film and an optimum PEDOT:PSS/MoO3-ammonia composite HTL can be explained by the enhanced carrier recombination through better hole injection and film morphology optimization, as well as the reduced exciton quenching at HTL/CH3NH3PbBr3 interface. These results present a promising strategy for the device engineering of high efficiency PeLEDs

New treatment methods for myocardial infarction

For a long time, cardiovascular clinicians have focused their research on coronary atherosclerotic cardiovascular disease and acute myocardial infarction due to their high morbidity, high mortality, high disability rate, and limited treatment options. Despite the continuous optimization of the therapeutic methods and pharmacological therapies for myocardial ischemia–reperfusion, the incidence rate of heart failure continues to increase year by year. This situation is speculated to be caused by the current therapies, such as reperfusion therapy after ischemic injury, drugs, rehabilitation, and other traditional treatments, that do not directly target the infarcted myocardium. Consequently, these therapies cannot fundamentally solve the problems of myocardial pathological remodeling and the reduction of cardiac function after myocardial infarction, allowing for the progression of heart failure after myocardial infarction. Coupled with the decline in mortality caused by acute myocardial infarction in recent years, this combination leads to an increase in the incidence of heart failure. As a new promising therapy rising at the beginning of the twenty-first century, cardiac regenerative medicine provides a new choice and hope for the recovery of cardiac function and the prevention and treatment of heart failure after myocardial infarction. In the past two decades, regeneration engineering researchers have explored and summarized the elements, such as cells, scaffolds, and cytokines, required for myocardial regeneration from all aspects and various levels day and night, paving the way for our later scholars to carry out relevant research and also putting forward the current problems and directions for us. Here, we describe the advantages and challenges of cardiac tissue engineering, a contemporary innovative therapy after myocardial infarction, to provide a reference for clinical treatment

Plasmonic-Enhanced Organic Light-Emitting Diodes Based on a Graphene Oxide/Au Nanoparticles Composite Hole Injection Layer

Organic light-emitting diodes (OLEDs) have drawn a great deal of attention due to their broad applications in lighting and displaying. With the development of nanotechnology, surface plasmas have been widely used in photonics, microscopes, solar cells and biosensors. In this paper, by inserting graphene oxide (GO), Au nanoparticles (Au NPs) and GO/Au NP composite structures between the hole transport layer (NPB) and indium tin oxide (ITO) anode, respectively, the electroluminescent performance of Alq3-based OLEDs was significantly enhanced. Compared to the reference devices, the devices with the composite inserting layer containing 10% GO/Au NP doping have the best electroluminescent performance, which improved 47.9% in maximum luminance, 49.2% in maximum current efficiency and 45.3% in maximum external quantum efficiency (EQE). Such substantial enhancement of photoelectric performance can be attributed to the combined effects of LSPR coupling and the better hole transport property by introducing Au NPs and a graphene oxide-doped layer