Nonvolatile memory characteristics associated with oxygen ion exchange in thin-film transistors with indium-zinc oxide channel and HfO2-x gate oxide

Non-charge-storage-based nonvolatile memory characteristics associated with oxygen ion exchange are demonstrated in a thin-film transistor (TFT) composed of an indium-zinc oxide (IZO) channel and an oxygen-deficient HfO2???x gate oxide. A nonvolatile increase in drain current and a reduced threshold voltage are obtained upon application of positive gate voltage, with the opposite characteristics upon application of negative voltage. The device shows nonvolatile retention properties and suitable endurance properties after repeated operations. Modulation of channel conductance occurs as a results of oxygen ion exchange between the HfO2???x gate oxide and the IZO channel, which consequently alters the oxygen vacancy concentration in the IZO channel; these vacancies act as n-type dopants. For comparison, a device with a thin SiO2 layer inserted between the HfO2???x gate oxide and the IZO channel to prevent oxygen ion exchange shows only the increased threshold voltage upon application of a positive gate voltage as a result of electron charging. These results verify the conductance modulation mechanism associated with oxygen ion exchange at the interface of the HfO2???x gate oxide and the IZO channel. In addition, the nonvolatile memory characteristics of the device are indicative of its potential for non-charge-storage-based nonvolatile memory application

Change in peak expiratory flow rate after the head-tilt/chin-lift maneuver among young, healthy, and conscious volunteers

Objective The head-tilt/chin-lift (HT/CL) is a simple, routinely used maneuver to open the upper airway. Changes in the peak expiratory flow rate (PEFR) before and after the HT/CL maneuver have not been evaluated among conscious volunteers who are regarded as a control cohort. Methods Sixty healthy 20-year-old volunteers (30 males and 30 females) were enrolled. The supine position was defined as the position at which the ear-eye line was at a 10° angle to the horizontal. The HT/CL position was defined as the position at which the ear-eye line was at a 25° angle to the horizontal. PEFR was measured using a hand-held device with the subject in the supine position (pre-PEFR) and HT/CL position (post-PEFR), respectively. One set was defined as these two measurements. Five sets of measurements were performed on each subject (300 sets). The set with the maximal and minimal difference between pre-PEFR and post-PEFR were excluded from the analysis. We used a paired t-test to compare the mean pre-PEFR and post-PEFR values for the entire group and subgroups divided by sex, height, body weight, body mass index and response status. Results Overall, 360 measurements (180 sets) were analyzed. The mean pre-PEFR and post-PEFR were 316.1±87.6 and 346.5±94.7 L/min, respectively. Further, significant differences were observed for sex, height, body weight, and body mass index. In 10 subjects, post-PEFR was lower than pre-PEFR. Conclusion PEFR increased by 9.6% after the HT/CL maneuver in young conscious subjects, but some subjects showed decreased PEFR after the HT/CL maneuver

Comparison of the National Early Warning Score+Lactate score with the pre-endoscopic Rockall, Glasgow-Blatchford, and AIMS65 scores in patients with upper gastrointestinal bleeding

Objective We compared the predictive value of the National Early Warning Score+Lactate (NEWS+L) score with those of other parameters such as the pre-endoscopic Rockall score (PERS), Glasgow-Blatchford score (GBS), and albumin, international normalized ratio, altered mental status, systolic blood pressure, age older than 65 years score (AIMS65) among patients with upper gastrointestinal bleeding (UGIB). Methods We conducted a retrospective study of patients with UGIB during 2 consecutive years. The primary outcome was the composite of in-hospital death, intensive care unit admission, and the need for ≥5 packs of red blood cell transfusion within 24 hours. Results Among 530 included patients, the composite outcome occurred in 59 patients (19 in-hospital deaths, 13 intensive care unit admissions, and 40 transfusions of ≥5 packs of red blood cells within 24 hours). The area under the receiver operating characteristic curve of the NEWS+L score for the composite outcome was 0.76 (95% confidence interval, 0.70 to 0.82), which demonstrated a significant difference compared to PERS (0.66, 0.59–0.73, P=0.004), but not to GBS (0.70, 0.64–0.77, P=0.141) and AIMS65 (0.76, 0.70–0.83, P=0.999). The sensitivities of NEWS+L scores of 3 (n=34, 6.4%), 4 (n=92, 17.4%), and 5 (n=171, 32.3%) were 100%, 98.3%, and 96.6%, respectively, while the sensitivity of an AIMS65 score of 0 (n=159, 30.0%) was 91.5%. Conclusion The NEWS+L score showed better discriminative performance than the PERS and comparable discriminative performance to the GBS and AIMS65. The NEWS+L score may be used to identify low-risk patients among patients with UGIB

Estimation of Nationwide Vaccination Coverage and Comparison of Interview and Telephone Survey Methodology for Estimating Vaccination Status

This study compared interview and telephone surveys to select the better method for regularly estimating nationwide vaccination coverage rates in Korea. Interview surveys using multi-stage cluster sampling and telephone surveys using stratified random sampling were conducted. Nationwide coverage rates were estimated in subjects with vaccination cards in the interview survey. The interview survey relative to the telephone survey showed a higher response rate, lower missing rate, higher validity and a less difference in vaccination coverage rates between card owners and non-owners. Primary vaccination coverage rate was greater than 90% except for the fourth dose of DTaP (diphtheria/tetanus/pertussis), the third dose of polio, and the third dose of Japanese B encephalitis (JBE). The DTaP4: Polio3: MMR1 fully vaccination rate was 62.0% and BCG1:HepB3:DTaP4:Polio3:MMR1 was 59.5%. For age-appropriate vaccination, the coverage rate was 50%-80%. We concluded that the interview survey was better than the telephone survey. These results can be applied to countries with incomplete registry and decreasing rates of landline telephone coverage due to increased cell phone usage and countries. Among mandatory vaccines, efforts to increase vaccination rate for the fourth dose of DTaP, the third dose of polio, JBE and regular vaccinations at recommended periods should be conducted in Korea

Administrative reform using information and communication technologies(ICTS) in Korea

The purpose of this study is to explain govemment efforts for administrative reform using ICTs in Korea. Especially, this study focuses on how the government informs, consults with and engages citizens using ICTs through an analysis of OPEN system in Seoul. Firstly, the political backgrounds and the institutions for constructing the e-government have been analyzed. Secondly, the OPEN system in Seoul has been analyzed. The result of this study shows that constructuring the e-governrnent as a means of administrative reform strengthens public participation and transparency in policy making process in spite of a few obstacles such as digital divide, secrecy problem

Write-Once-Read-Many-Times Memory Characteristics with a Large Memory Window Operating at a Low Voltage by Li-Ion Incorporation from the LiCoO x Ion-Supplying Layer into the InGaZnO Channel of a Thin-Film Transistor

Write-once-read-many-times (WORM)memory characteristicswith alarge memory window are demonstrated in a thin-film transistor (TFT)composed of an indium-gallium-zinc oxide (IGZO) channel and a lithium-cobaltoxide (LiCoO x ) ion-supplying layer inthe gate oxide. While the device with a thicker (5 nm) tunneling oxideshowing a threshold voltage shift (Delta V (T)) of about 5 V by electron charging upon positive gate voltage (V (GS)) sweep to +25 V, the device with a 2 nm-thicktunneling oxide exhibits a large memory window with Delta V (T) > 20 V by Li-ion migration from LiCoO x to IGZO channel, which can be controlledas multilevel states with respect to the V (GS) amplitude. Incorporation of Li ions into the IGZO channel actingas p-type dopants reduces carrier concentration in the channel andconsequently increases V (T). The increased V (T) and the consequently reduced drain currentare not instantly restored back by applying negative V (GS), featuring WORM memory characteristics. Although thedevice undergoes partial retention loss, the retention remains upto about 90% after 100 min of retention time. These results verifyWORM memory operations in the IGZO TFTs through gate voltage-drivenLi-ion incorporation into the IGZO channel to modify its conductivestates instead of using a typical electrical charging route

An experimental study of the effect of motile bacteria on the fluid displacement in porous media

Multiphase flow patterns in porous media largely depend on the properties of the fluids and interfaces such as viscosity, surface tension, and contact angle. Microorganisms in soils change the fluid and interfacial properties, and thus can alter multiphase fluid flow in porous media. This study investigates the impact of motile bacterium Escherichia coli (E. coli) on fluid displacement patterns in a microfluidic chip. The fluid displacement is observed during the saturation and the desaturation processes of the microfluidic chip with and without E.coli suspension. Time-lapse photography results show that the presence of E.coli alters the displacement patterns during the wetting and drying process and changes the residual saturation of the chip. Although studies of the impacts of motility on interfacial properties remain elusive, these results bring the expectation to the manipulation of multiphase transport in porous media and the adaptive control of industrial and environmental flow processes using active particles

Impacts of motile

Immiscible multiphase flow in porous media is largely affected by interfacial properties, manifested in contact angle and surface tension. The gas-liquid surface tension can be significantly altered by suspended particles at the interface. Particle-laden interfaces have unique properties, for example, a lower surface tension of interfaces laden with surfactants or nanoparticles. This study investigates the impacts of a motile bacterium Escherichia coli (E. coli, strain ATCC 9637) on the air-water surface tension. Methods of the maximum bubble pressure, the du Noüy ring, and the pendant droplet are used to measure the surface tension of the motile-bacteria-laden interfaces. Measured surface tension remains independent to the E. coli concentration when using the maximum bubble pressure method, decreases with increased E. coli concentration in the du Noüy ring method, and presents time-dependent changes by the pendant drop method. The analyses show that the discrepancies may come from the different convection-diffusion processes of E. coli in the flow among various testing methods