Dependence of Positive Bias Stress Instability on Threshold Voltage and Its Origin in Solution-Processed Aluminum-Doped Indium Oxide Thin-Film Transistors.

The initial electrical characteristics and bias stabilities of thin-film transistors (TFTs) are vital factors regarding the practical use of electronic devices. In this study, the dependence of positive bias stress (PBS) instability on an initial threshold voltage (VTH) and its origin were analyzed by understanding the roles of slow and fast traps in solution-processed oxide TFTs. To control the initial VTH of oxide TFTs, the indium oxide (InOx) semiconductor was doped with aluminum (Al), which functioned as a carrier suppressor. The concentration of oxygen vacancies decreased as the Al doping concentration increased, causing a positive VTH shift in the InOx TFTs. The VTH shift (∆VTH) caused by PBS increased exponentially when VTH was increased, and a distinct tendency was observed as the gate bias stress increased due to a high vertical electric field in the oxide dielectric. In addition, the recovery behavior was analyzed to reveal the influence of fast and slow traps on ∆VTH by PBS. Results revealed that the effect of the slow trap increased as the VTH moved in the positive direction; this occured because the main electron trap location moved away from the interface as the Fermi level approached the conduction band minimum. Understanding the correlation between VTH and PBS instability can contribute to optimizing the fabrication of oxide TFT-based circuits for electronic applications.

Atomically Thin Amorphous Indium-Oxide Semiconductor Film Developed Using a Solution Process for High-Performance Oxide Transistors.

High-performance oxide transistors have recently attracted significant attention for use in various electronic applications, such as displays, sensors, and back-end-of-line transistors. In this study, we demonstrate atomically thin indium-oxide (InOx) semiconductors using a solution process for high-performance thin-film transistors (TFTs). To achieve superior field-effect mobility and switching characteristics in TFTs, the bandgap and thickness of the InOx were tuned by controlling the InOx solution molarity. As a result, a high field-effect mobility and on/off-current ratio of 13.95 cm2 V-1 s-1 and 1.42 × 1010, respectively, were achieved using 3.12-nanometer-thick InOx. Our results showed that the charge transport of optimized InOx with a thickness of 3.12 nm is dominated by percolation conduction due to its low surface roughness and appropriate carrier concentration. Furthermore, the atomically thin InOx TFTs showed superior positive and negative gate bias stress stabilities, which are important in electronic applications. The proposed oxide TFTs could provide an effective means of the fabrication of scalable, high-throughput, and high-performance transistors for next-generation electronic applications.

Low-Temperature Enhancement-Mode Amorphous Oxide Thin-Film Transistors in Solution Process Using a Low-Pressure Annealing.

The interest in low processing temperature for printable transistors is rapidly increasing with the introduction of a new form factor in electronics and the growing importance of high throughput. This paper reports the fabrication of low-temperature-processable enhancement-mode amorphous oxide thin-film transistors (TFTs) using the solution process. A facile low-pressure annealing (LPA) method is proposed for the activation of indium oxide (InOx) semiconductors at a significantly low processing temperature of 200 °C. Thermal annealing at a pressure of about ~10 Torr induces effective condensation in InOx even at a low temperature. As a result, the fabricated LPA InOx TFTs not only functioned in enhancement mode but also exhibited outstanding switching characteristics with a high on/off current ratio of 4.91 × 109. Furthermore, the LPA InOx TFTs exhibit stable operation under bias stress compared to the control device due to the low concentration of hydroxyl defects.

The Decline of Physical Activity with Age in School-Aged Children with Cerebral Palsy: A Single-Center Cross-Sectional Observational Study.

Maintaining physical activity is important for children with cerebral palsy (CP). This study examined whether age predicted habitual physical activity (HPA) or cardiorespiratory fitness (CRF) in school-aged children with CP and clarified the relationship between HPA and CRF. We utilized cross-sectional data from 39 children with CP (18 girls and 21 boys; mean age 7.44 years; mean body weight 24.76 kg; mean body mass index 15.97 kg/m2; hemiplegic or diplegic CP). The participants wore an accelerometer (ActiGraph) for five days to measure HPA, physical activity energy expenditure (kcal/kg/d), sedentary physical activity (%SPA), light physical activity, moderate-to-vigorous physical activity (%MVPA), and activity counts (counts/min). Participants underwent cardiopulmonary exercise tests on a treadmill using a modified Naughton protocol. Linear regression and correlation analyses were performed. p-value (two-tailed) < 0.05 was considered statistically significant. Age was positively associated with SPA. MVPA negatively correlated with resting heart rate (HR), and activity counts were negatively correlated with resting HR. In conclusion, our study found strong evidence of a negative association between HPA and age in school-aged children with CP. It highlights the importance of creating and improving recreational opportunities that promote physical activity in all children with CP, regardless of whether they are considered therapeutic.

One-Stop Strategy for Obtaining Controllable Sensitivity and Feasible Self-Patterning in Silver Nanowires/Elastomer Nanocomposite-Based Stretchable Ultrathin Strain Sensors.

In this study, selective photo-oxidation (SPO) is proposed as a simple, fast, and scalable one-stop strategy that enables simultaneous self-patterning and sensitivity adjustment of ultrathin stretchable strain sensors. The SPO of an elastic substrate through irradiation time-controlled ultraviolet treatment in a confined region enables precise tuning of both the surface energy and the elastic modulus. SPO induces the hydrophilization of the substrate, thereby allowing the self-patterning of silver nanowires (AgNWs). In addition, it promotes the formation of nonpermanent microcracks of AgNWs/elastomer nanocomposites under the action of strain by increasing the elastic modulus. This effect improves sensor sensitivity by suppressing the charge transport pathway. Consequently, AgNWs are directly patterned with a width of 100 µm or less on the elastic substrate, and AgNWs/elastomer-based ultrathin and stretchable strain sensors with controlled sensitivity work reliably in various operating frequencies and cyclic stretching. Sensitivity-controlled strain sensors successfully detect both small and large movements of the human hand.

Physical Activity Energy Expenditure Predicts Quality of Life in Ambulatory School-Age Children with Cerebral Palsy.

BACKGROUND: Participation in physical activities is positively associated with better quality of life in children with cerebral palsy (CP). The objective of this study was to elucidate the relationship between the intensity of habitual physical activity (HPA) measured with an accelerometer and health-related quality of life (HRQOL) in school-age children with CP. METHOD: A secondary analysis of the cross-sectional data of 46 ambulatory children with CP was conducted. The participants wore an accelerometer for seven days to measure HPA: activity counts (counts/min) and physical activity energy expenditure (PAEE, kcal/kg/day), as well as %moderate-to-vigorous intensity physical activity (%MVPA), %light intensity physical activity (%LPA), and %sedentary physical activity (%SPA) were measured. Pediatric Quality of Life Inventory (PedsQL) 4.0 Generic Core Scales and Child Health Questionnaire Parent Form 50 Questions (CHQ-PF50) were used to measure HRQOL. A Pearson analysis and a hierarchical regression analysis were performed. RESULTS: PAEE significantly predicted the results of the PedsQL(child) physical domain (ß = 0.579, p = 0.030), PedsQL(child) emotional domain (ß = 0.570, p = 0.037), PedsQL(child) social domain (ß = 0.527, p = 0.043), and PedsQL(child) total (ß = 0.626, p = 0.017). However, other HPA parameters could not predict any other HRQOL. CONCLUSIONS: PAEE could be used as a biomarker in studies on HRQOL and HPA in ambulatory school-age children with CP.

Li-diffusion at the interface between Li-metal and [Pyr14][TFSI]-ionic liquid: Ab initio molecular dynamics simulations.

We previously reported comprehensive density functional theory-molecular dynamics (DFT-MD) at 400 K to determine the composition and structure of the solid electrolyte interface (SEI) between a Li anode and [Pyr14][TFSI] ionic liquid. In this paper, we examined diffusion rates in both the Li-electrode region and SEI compact layer in smaller 83Li/2[TFSI] and larger 164Li/4[TFSI] systems. At 400 K, the Li-diffusion constant in the Li-region is 1.35 × 10-10 m2/s for 83Li/2[TFSI] and 5.64 × 10-10 m2/s for 164Li/4[TFSI], while for the SEI it is 0.33 × 10-10 m2/s and 0.22 × 10-10 m2/s, thus about one order slower in the SEI compared to the Li-region. This Li-diffusion is dominated by hopping from the neighbor shell of one F or O to the neighbor shell of another. Comparing the Li-diffusion at different temperatures, we find that the activation energy is 0.03 and 0.11 eV for the Li-region in the smaller and larger systems, respectively, while for the SEI it is 0.09 and 0.06 eV.

Interface Structure in Li-Metal/[Pyr14][TFSI]-Ionic Liquid System from ab Initio Molecular Dynamics Simulations.

Ionic liquids (ILs) are promising materials for application in a new generation of Li batteries. They can be used as electrolyte or interlayer or incorporated into other materials. ILs have the ability to form a stable solid electrochemical interface (SEI), which plays an important role in protecting the Li-based electrode from oxidation and the electrolyte from extensive decomposition. Experimentally, it is hardly possible to elicit fine details of the SEI structure. To remedy this situation, we have performed a comprehensive computational study (density functional theory-based molecular dynamics) to determine the composition and structure of the SEI compact layer formed between the Li anode and [Pyr14][TFSI] IL. We found that the [TFSI] anions quickly reacted with Li and decomposed, unlike the [Pyr14] cations which remained stable. The obtained SEI compact layer structure is nonhomogeneous and consists of the atomized S, N, O, F, and C anions oxidized by Li atoms.

Kinetics of collision-induced reactions between hard-sphere reactants.

We investigate the reaction kinetics of hard-sphere reactants that undergo reaction upon collision. When the reaction probability at a given collision is unity, the Noyes rate theory provides an exact expression of the rate coefficient. For the general case with the reaction probability less than unity, Noyes assumed that successive recollision times between a tagged pair of reactants are decorrelated. We show that with this renewal assumption, the rate theory of Wilemski and Fixman yields the same rate coefficient expression as the Noyes theory. To evaluate the validity of the renewal assumption, we carry out molecular dynamics simulations. Contrary to the usual expectation, we find that the renewal assumption works better at higher particle densities. The present study shows that the rate coefficient for collision-induced hard-sphere reactions can be estimated with great accuracy by using the first recollision time distribution alone, regardless of the magnitude of the reaction probability at a given collision.

Mean first passage time for the contact between the ends of a chain polymer.

We investigate the first passage times for the contact between the ends of a Rouse chain, whose initial separation is greater than a predefined contact distance, sigma, and equilibrium-distributed. An approximate analytic expression for the mean first passage time is obtained and compared with the results of previous theories and Brownian dynamics simulations. We find that the results of the present theory are in better agreement with Brownian dynamics simulation results than those of previously reported theories.

Natural maternal transmission of H. pylori in Mongolian gerbils.

AIM: To investigate maternal H. pylori infection status to determine the potential of maternal transmission. METHODS: In the present study, we examined these issues in an experimental murine model, which is a Mongolian gerbil model that has been reported as an optimal laboratory animal model to study H. pylori. Pregnant Mongolian gerbils, infected experimentally with H. pylori, were divided into as four groups. Following the experimental design, the stomachs of the mother and litters were isolated and assessed for transmission of H. pylori at the prenatal period, parturition day, 1-wk old and 3-wk old respectively. Bacterial culture and polymerase chain reaction (PCR) were used to examine the presence of transmitted H. pylori. RESULTS: All litters showed no transmission of H. pylori during pregnancy and at parturition day. However, they revealed 33.3% and 69.6% at 1-wk and 3-wk of age respectively by PCR. CONCLUSION: These results suggested that vertical infection during the prenatal period or delivery procedure is unlikely as a route of mother-to-child H pylori infection. It may be that H. pylori is acquired through breast-feeding, contaminated saliva and fecal-oral transmission during co-habitation.

Generalization of Wilemski-Fixman-Weiss decoupling approximation to the case involving multiple sinks of different sizes, shapes, and reactivities.

We generalize the Wilemski-Fixman-Weiss decoupling approximation to calculate the transient rate of absorption of point particles into multiple sinks of different sizes, shapes, and reactivities. As an application we consider the case involving two spherical sinks. We obtain a Laplace-transform expression for the transient rate that is in excellent agreement with computer simulations. The long-time steady-state rate has a relatively simple expression, which clearly shows the dependence on the diffusion constant of the particles and on the sizes and reactivities of sinks, and its numerical result is in good agreement with the known exact result that is given in terms of recursion relations.

Critical assessment of the automated AutoDock as a new docking tool for virtual screening.

A major problem in virtual screening concerns the accuracy of the binding free energy between a target protein and a putative ligand. Here we report an example supporting the outperformance of the AutoDock scoring function in virtual screening in comparison to the other popular docking programs. The original AutoDock program is in itself inefficient to be used in virtual screening because the grids of interaction energy have to be calculated for each putative ligand in chemical database. However, the automation of the AutoDock program with the potential grids defined in common for all putative ligands leads to more than twofold increase in the speed of virtual database screening. The utility of the automated AutoDock in virtual screening is further demonstrated by identifying the actual inhibitors of various target enzymes in chemical databases with accuracy higher than the other docking tools including DOCK and FlexX. These results exemplify the usefulness of the automated AutoDock as a new promising tool in structure-based virtual screening.

Experimental peritonitis induced by oral administration of indomethacin in Mongolian gerbils.

The possibility of inducing peritoneal inflammation in three murine species (gerbils, rats and mice) via the oral administration of indomethacin was investigated with the overall aim of developing an experimental animal model for human peritonitis. Gerbils given high doses of indomethacin at a rate of 30 mg and 40 mg/kg body weight showed swelling of the abdomen, depression and dyspnea within 4 days after the treatment. The severity of the clinical symptoms increased with time. The animals were confirmed as having developed peritonitis based on the pathological features including inflammation of the peritoneum, and fibrinous adhesion of the abdominal organs in the abdominal cavity. The severity of peritonitis increased with increasing dose of indomethacin, and was not related to the gender of the animal. On the other hand, peritoneal inflammation did not develop in the rats and mice even at high doses. Therefore, the administration of 30 mg/kg body weight of indomethacin is an effective and simple method of inducing peritonitis in 5-week-old Mongolian gerbils. The animal peritonitis model used in this study can be used as an effective tool for examining potential therapeutic compounds for preventing peritoneal damage during peritonitis, and provide insight into the pathophysiology of peritonitis.

An efficient molecular dynamics simulation method for calculating the diffusion-influenced reaction rates.

We present a molecular dynamics (MD) simulation method for calculating the diffusion-influenced reaction rates in the limit of low reactant concentrations. To calculate the reaction rate coefficient, we use MD trajectories of a nonreactive equilibrium system that are initiated with a pair of reactant molecules in reactive configuration. Hence reaction systems involving complicated reactant molecules with geometrically restricted reactivities can be treated with comparable efficiency as the simple hard-sphere reaction system. Compared to the similar MD method proposed by Van Beijeren, Dong, and Bocquet [J. Chem. Phys. 114, 6265 (2001)], the present method has a couple of advantages. First, reactions involving more general sink functions can be treated. Second, more accurate results can be obtained when the reaction probability upon collision is less than unity. As an application, we investigate the effects of nondiffusive dynamics and hydrodynamic interaction of reactants on the reaction rate.