特別な酸化物コンタクト構造を持つ高性能有機薄膜トランジスタとデバイス物性の評価

Organic thin-film transistors (OTFTs) have attracted increasing interest for their potential advantages, such as, low cost, lightweight and possible fabricating on flexible substrate, as well as large-area feasibility. For constructing a high performance top-contact OTFT, it is very important to understand the influence of interfaces, which play a crucial role in the overall performance of the device. Mainly there are two kinds of interfaces in the OTFT. First is in between the semiconductor and the gate dielectric, where the conducting channel forms. The second one is in between the source/drain (S/D) electrodes and the semiconductor layer where charge carriers are injected.First, I particularly discussed the latter interface. Organic and metal interfaces mostly limit the performance of the device and field effect mobility is also decreased. In earlier reports it has been shown that the diffusion between the metal electrode and pentacene reduce the hole　injection carrier at the interface which causes the increase in barrier height and contact resistance which effect the performance of the OTFTs. It is shown that the contact between the S/D electrodes and the organic semiconductor can be improved by inserting transition metal oxide layer as carrier injection layers. Because of good electronic properties, transition metal oxides such as molybdenum oxide (MoO_3), tungsten oxide (WO_3) and vanadium oxide (V_2O_5), and other oxides such as germanium oxide (GeO), titanium oxide (TiO_2) offer a unique opportunity to control the work function, and hence increase the charge-injection properties. Therefore, by modifying the organic/electrode interface, the S/D electrodes do not directly contact with pentacene layer and hence significantly reduces the contact resistance, barrier height and provides protection from diffusion and other chemical reactions, which increase device performance.Second, I investigated that the enhancement of the charge injection and field effect mobility by inserting a thin (5 nm) MoO_3, GeO, WO_3 and TiO_2 interlayer between the Au electrode and pentacene layer in a top contact pentacene based organic thin-film transistor (OTFTs).In comparison with the pentacene-based OTFT with only-Au electrode, the device performance with bilayer electrode has been considerably improved. The device performance including field effect mobility, threshold voltage, and On/Off ratio of all the device after modification was highly improved, and the highest mobility of 0.96 cm^2/V1s, threshold voltage of -4 V, and highest on/off ratio of 5.2×10^4 were achieved in the device with 5 nm GeO. I further investigated the temperature dependence of I_D–V_D characteristics which showed strong temperature dependence in all the devices.Third, the obvious temperature dependence of I_D-V_D curves in all devices suggests that the charge injection characteristics can be fitted by the Schottky emission mechanism. By plotting the relationship between ln(I) vs V^ and extrapolating straight lines to the ordinal point, the current at zero voltage I0 is determined. By using the values of I0, the relationship between ln(I_0/T^2) vs 1/T is plotted and from the resulting slope of extrapolated lines. While in case of bilayer MoO_3/Au shows 0.03 eV, WO_3/Au shows 0.05 eV, TiO_2/Au showed 0.04 eV and with only Au electrodes barrier height of 0.12 eV is achieved. The lowest barrier heights of 0.01 eV could be achieved in case of bilayer GeO/Au electrodes. It is assumed that the barrier height was dramatically reduced by inserting thin oxide layer between the Au and pentacene layer. Similarly, from surface morphology of pentacene, the root mean square roughness is also decreased after inserting metal oxide layer. The main factor for the improvement in the performance of the OTFTs with bilayer electrodes was explained in terms of the reduction in barrier height and smoothed surface roughness of active layer. Therefore, the combination of a thin oxide layer with Au as a bi-layer electrode is an effective way to improve the characteristics of OTFTs, which makes the device suitable for commercial applications.Finally, I further reported the enhanced carrier injection in pentacene OTFTs with a thin MoO_3- doped pentacene layer between pentacene semiconductor and the S/D electrodes. Device performance including drain current, field effect mobility, and threshed voltage are improved by employing a MoO_3-doped pentacene thin layer. The barrier height at the Au/pentacene interface is lowered from 0.12 to 0.05 eV after inserting a MoO_3-doped pentacene thin layer between them.富山大学・富理工博甲第64号・Alam Mir Waqas・2013/09/27富山大

Lumbar morphometry: A study of lumbar vertebrae from a Pakistani population using computed tomography scans

Study design: A cross-sectional study.Purpose: To describe the characteristics of lumbar vertebrae of Pakistani patients reporting at a tertiary care hospital and compare with studies from other populations.Overview of literature: Several studies have been conducted to determine morphometry of lumbar vertebrae. Most of the studies involve Caucasian populations, still data on other populations still sparse. This is the first study describing lumbar morphometry of a Pakistani population.Methods: An observational study was conducted based on a review of thin-cut (3 mm) computed topographic images of lumbar vertebrae. Two-hundred and twenty vertebrae from forty-nine patients were studied, and various dimensions were analyzed.Results: Generally, the size of the vertebrae, vertebral canals and recesses were found to be greater in male patients. The difference was statistically significant for transverse and anteroposterior diameters of the vertebral bodies and sagittal diameter of pedicles on the left side (p\u3c0.05). Comparison of populations revealed statistically significant differences in pedicle dimensions between Pakistani population and others.Conclusions: This study provides anatomical knowledge of the lumbar region in a sample population of Pakistan. There were significant differences in various dimensions of lumbar vertebrae between female and male patients. This would prove to be critical for performing a safe operation

Numerical evaluation of dry-stacked masonry walls against blast loading

This research intends to numerically study the out-of-plane behaviour of confined dry-stacked masonry (CDSM) walls against blast loading. CDSM is a mortar-less interlocking masonry system consisting of Interlocking Compressed Earth Block (ICEB) laid in stretcher bond with reinforced concrete (RC) confining elements. A nonlinear numerical model is developed using advanced finite element software ABAQUS to study the response of CDSM walls subjected to explosive loads of 8 kgs Trinitrotoluene (TNT). The blast load was detonated at 2m from the walls of confined masonry at a height of 1m above ground. The resulting damage distribution and displacement time history were compared for two walls with different reinforcement. This study helps to visualize the effect of diagonal reinforcement along with the performance of CDSM walls against blast loading using ABAQUS. The results shows less damage for diagonally reinforced wall

Kaempferol as a dietary anti-inflammatory agent: current therapeutic standing

Inflammation is a physiological response to different pathological, cellular or vascular damages due to physical, chemical or mechanical trauma. It is characterized by pain, redness, heat and swelling. Current natural drugs are carefully chosen as a novel therapeutic strategy for the management of inflammatory diseases. Different phytochemical constituents are present in natural products. These phytochemicals have high efficacy both in vivo and in vitro. Among them, flavonoids occur in many foods, vegetables and herbal medicines and are considered as the most active constituent, having the ability to attenuate inflammation. Kaempferol is a polyphenol that is richly found in fruits, vegetables and herbal medicines. It is also found in plant-derived beverages. Kaempferol is used in the management of various ailments but there is no available review article that can summarize all the natural sources and biological activities specifically focusing on the anti-inflammatory effect of kaempferol. Therefore, this article is aimed at providing a brief updated review of the literature regarding the anti-inflammatory effect of kaempferol and its possible molecular mechanisms of action. Furthermore, the review provides the available updated literature regarding the natural sources, chemistry, biosynthesis, oral absorption, metabolism, bioavailability and therapeutic effect of kaempferol

Fundamentals Applications of Controlled Release Drug Delivery

The advancement of pharmacology and pharmacokinetics highlighted the important role of drug release kinetics in the determination of therapeutic outcomes of treatments. The advent of modified release dosage forms marked a significant innovation. Technological progressions in coating methods gained momentum in the late 1800s, encompassing innovations like sugar and enteric coatings applied to pills and tablets. Subsequent advancements led to the refinement of enteric coatings for tablets, which eventually evolved into the incorporation of a secondary drug within the sugar coating layer. However, the initial patent for oral-sustained release formulations was awarded to Lipowski. His formulation comprised miniature-coated beads designed to achieve gradual and consistent drug release. This concept was subsequently refined by Blythe, leading to the introduction of the first commercially available sustained release product. Over the last three decades, the escalating complexities associated with bringing new drugs to market, coupled with the recognized merits of Controlled Release Drug Delivery Systems (CRDDS). Presently, oral controlled drug delivery systems have emerged as significant avenues, particularly for compounds characterized by high water solubility and abbreviated biological half-lives. Beyond oral administration, diverse routes such as transdermal, ocular, vaginal, and parenteral approaches are utilized for controlled release of various therapeutic agents

Comparative Analysis of Shear Strength Prediction Models for Reinforced Concrete Slab-Column Connections

This research aims at comparative analysis of shear strength prediction at slab-column connection, unifying machine learning, design codes and Finite Element Analysis. Current design codes (CDCs) of ACI 318-19 (ACI), Eurocode 2 (EC2), Compressive Force Path (CFP) method, Feed Forward Neural Network (FNN) based Artificial Neural Network (ANN), PSO-based FNN (PSOFNN), and BAT algorithm-based BATFNN are used. The study is complemented with FEA of slab for validating the experimental results and machine learning predictions.In the case of hybrid models of PSOFNN and BATFNN, mean square error is used as an objective function to obtain the optimized values of the weights, that are used by Feed Forward Neural Network to perform predictions on the slab data. Seven different models of PSOFNN, BATFNN, and FNN are trained on this data and the results exhibited that PSOFNN is the best model overall. PSOFNN has the best results for SCS=1 with highest value of R as 99.37% and lowest of MSE, and MAE values of 0.0275%, and 1.214% respectively which are better than the best FNN model for SCS=4 having the values of R, MSE, and MAE as 97.464%, 0.0492%, and 1.43%, respectively.Comment: 34 Pages,25 Figure

Bacterobilia in acute cholecystitis: bile cultures\u27 isolates, antibiotic sensitivities and antibiotic usage. a study on a Pakistani population.

Abstract Acute cholecystitis is one of the most common acute surgical conditions. Laparoscopic cholecystectomy remains the mainstay of treatment. In patients managed non-operatively, antibiotics play an important role in the treatment of cholecystitis. The current retrospective observational study was conducted at a tertiary care hospital in Karachi, and comprised medical records of patients admitted between 2008 and 2014with acute cholecystitis and in whom bile cultures were obtained. Of the 509 patients with a mean age of 51.15 ± 13.4years, early laparoscopic cholecystectomy (within 72hours) was performed on 473(92.9%) cases, while the rest underwent percutaneous cholecystostomy. Bile cultureswere positive in 171(33.6%) patients. Predominantly gram-negative organisms were isolated among a total of 137(27%), with E.coli 63(46%) being the most commonly isolated organism. Of the gram-positive organism, enterococcus 11(8%) was the most common. Antibiotic sensitivities were determined.Based on our findings gram-negative coverage alone should be sufficient in our segment of the population