Clinical narrative-aware deep neural network for emergency department critical outcome prediction.

Since early identification of potential critical patients in the Emergency Department (ED) can lower mortality and morbidity, this study seeks to develop a machine learning model capable of predicting possible critical outcomes based on the history and vital signs routinely collected at triage. We compare emergency physicians and the predictive performance of the machine learning model. Predictors including patients' chief complaints, present illness, past medical history, vital signs, and demographic data of adult patients (aged ≥ 18 years) visiting the ED at Shuang-Ho Hospital in New Taipei City, Taiwan, are extracted from the hospital's electronic health records. Critical outcomes are defined as in-hospital cardiac arrest (IHCA) or intensive care unit (ICU) admission. A clinical narrative-aware deep neural network was developed to handle the text-intensive data and standardized numerical data, which is compared against other machine learning models. After this, emergency physicians were asked to predict possible clinical outcomes of thirty visits that were extracted randomly from our dataset, and their results were further compared to our machine learning model. A total of 4,308 (2.5 %) out of the 171,275 adult visits to the ED included in this study resulted in critical outcomes. The area under the receiver operating characteristic curve (AUROC) and the area under the precision-recall curve (AUPRC) of our proposed prediction model is 0.874 and 0.207, respectively, which not only outperforms the other machine learning models, but even has better sensitivity (0.95 vs 0.41) and accuracy (0.90 vs 0.67) as compared to the emergency physicians. This model is sensitive and accurate in predicting critical outcomes and highlights the potential to use predictive analytics to support post-triage decision-making.

Improved diffusion and storage of lithium ions via recrystallization induced conducting pathways in a Li:Ta2O5-based electrolyte for all-solid-state electrochromic devices with enhanced performance.

In this study, we have investigated the improvements in the performance of an all-solid-state complementary electrochromic device (ECD) by using the proposed high pressure treatment (HPT). The Li:Ta2O5electrolyte layer was recrystallized by the HPT utilizing pressurized CO2gas (∼200 atm) and at low temperature (<60 °C), which enhanced the coloration performance of the WO3/Li:Ta2O5/NiO complementary ECD by ∼20%. The reliability and durability of the ECD were confirmed by long term transmittance retention measurements, which indicated an improvement in the coloration performance by ∼14% upon the release of the bias voltages. The ability of the devices that were fabricated with and without the HPT process to withstand high temperature environments was also verified. In addition, photoluminescence (PL) and transmittance measurements were carried out to examine the effects of the bonding between WO3and NiO. To determine the differences in lithium-ion (Li+) injection, electrical measurements were performed by utilizing varying pulse rising speeds to confirm device characteristics. The materials were characterized in terms of their composition and structure using high-resolution transmission electron microscopy along with energy-dispersive x-ray spectroscopy. Finally, a mechanistic model has been proposed to explain the improved EC characteristics based on the amorphous to crystalline transition accompanying the HPT process.

Attaining resistive switching characteristics and selector properties by varying forming polarities in a single HfO2-based RRAM device with a vanadium electrode.

This study proposes a method for a HfO2-based device to exhibit both resistive switching (RS) characteristics as resistive random access memory (RRAM) and selector characteristics by introducing vanadium (V) as the top electrode. This simple V/HfO2/TiN structure can demonstrate these two different properties depending on forming polarities. The RS mechanism is activated by a positive forming bias. In contrast, the selector property is induced by a negative forming bias. The material analyses firstly confirm the existence of V in the top electrode. Then the electrical measurements for the same V/HfO2/TiN structures but with different forming polarities were carried out to further investigate their DC sweeping characteristics to act as either a selector or RRAM device. Furthermore, reliability tests for both selector and RRAM devices were also conducted to confirm their switching stabilities. Finally, current fitting methods and temperature influence experiments were performed to investigate the carrier transport mechanisms. Finally, physical models were proposed to illustrate the selector property and RS mechanism for selector and RRAM devices, respectively. This simple device structure with its easy operating method accomplishes a significant advancement of devices combining both selector properties and RRAM for remarkable real applications in the near future.

Resistance Switching Characteristics Induced by O2 Plasma Treatment of an Indium Tin Oxide Film for Use as an Insulator in Resistive Random Access Memory.

In this study, an O2 inductively coupled plasma (ICP) treatment was developed in order to modify the characteristics of indium tin oxide (ITO) film for use as an insulator in resistive random access memory (RRAM). After the O2 plasma treatment, the previously conductive ITO film is oxidized and becomes less conductive. In addition, after capping the same ITO material for use as a top electrode, we found that the ITO/ITO(O2 plasma)/TiN device exhibits very stable and robust resistive switching characteristics. On the contrary, the nontreated ITO film for use as an insulator in the ITO/ITO/TiN device cannot perform resistance switching behaviors. The material analysis initially investigated the ITO film characteristics with and without O2 plasma treatment. The surface was less rough after O2 plasma treatment. However, the molar concentration of each element and measured sheet resistance results for the O2-plasma-treated ITO film were dramatically modified. Next, electrical measurements were carried out to examine the resistance switching stability under continuous DC and AC operation in this ITO/ITO(O2 plasma)/TiN device. Reliability tests, including endurance and retention, also proved its capability for use in data storage applications. In addition to these electrical measurements, current fitting method experiments at different temperatures were performed to examine and confirm the resistance switching mechanisms. This easily fabricated device, using a simple material combination, achieves excellent performance by using ITO with an O2 plasma treatment and can further the abilities of RRAM for use in remarkable potential applications.

Physical and chemical mechanisms in oxide-based resistance random access memory.

In this review, we provide an overview of our work in resistive switching mechanisms on oxide-based resistance random access memory (RRAM) devices. Based on the investigation of physical and chemical mechanisms, we focus on its materials, device structures, and treatment methods so as to provide an in-depth perspective of state-of-the-art oxide-based RRAM. The critical voltage and constant reaction energy properties were found, which can be used to prospectively modulate voltage and operation time to control RRAM device working performance and forecast material composition. The quantized switching phenomena in RRAM devices were demonstrated at ultra-cryogenic temperature (4K), which is attributed to the atomic-level reaction in metallic filament. In the aspect of chemical mechanisms, we use the Coulomb Faraday theorem to investigate the chemical reaction equations of RRAM for the first time. We can clearly observe that the first-order reaction series is the basis for chemical reaction during reset process in the study. Furthermore, the activation energy of chemical reactions can be extracted by changing temperature during the reset process, from which the oxygen ion reaction process can be found in the RRAM device. As for its materials, silicon oxide is compatible to semiconductor fabrication lines. It is especially promising for the silicon oxide-doped metal technology to be introduced into the industry. Based on that, double-ended graphene oxide-doped silicon oxide based via-structure RRAM with filament self-aligning formation, and self-current limiting operation ability is demonstrated. The outstanding device characteristics are attributed to the oxidation and reduction of graphene oxide flakes formed during the sputter process. Besides, we have also adopted a new concept of supercritical CO2 fluid treatment to efficiently reduce the operation current of RRAM devices for portable electronic applications.

Integrated one diode-one resistor architecture in nanopillar SiOx resistive switching memory by nanosphere lithography.

We report on a highly compact, one diode-one resistor (1D-1R) nanopillar device architecture for SiOx-based ReRAM fabricated using nanosphere lithography (NSL). The intrinsic SiOx-based resistive switching element and Si diode are self-aligned on an epitaxial silicon wafer using NSL and a deep-Si-etch process without conventional photolithography. AC-pulse response in 50 ns regime, multibit operation, and good reliability are demonstrated. The NSL process provides a fast and economical approach to large-scale patterning of high-density 1D-1R ReRAM with good potential for use in future applications.