Continuous quality improvement program and its results of Korean Society for Cytopathology.

BACKGROUND: Since 1995, the Korean Society for Cytopathology has overseen the Continuous Quality Improvement program for cytopathology laboratories. The Committee of Quality Improvement has carried out an annual survey of cytology data for each laboratory and set standards for proficiency tests. METHODS: Evaluations were conducted four times per year from 2008 to 2018 and comprised statistics regarding cytology diagnoses of previous years, proficiency tests using cytology slides provided by the committee, assessment of adequacy of gynecology (GYN) cytology slides, and submission of cytology slides for proficiency tests. RESULTS: A total of 206 institutes participated in 2017, and the results were as follows. The number of cytology tests increased from year to year. The ratio of liquid-based cytology in GYN gradually decreased, as most of the GYN cytology had been performed at commercial laboratories. The distribution of GYN diagnoses demonstrated nearly 3.0% as atypical squamous cells. The rate for squamous cell carcinoma was less than 0.02%. The atypical squamous cell/squamous intraepithelial lesion ratio was about 3:1 and showed an upward trend. The major discordant rate of cytology-histology in GYN cytology was less than 1%. The proficiency test maintained a major discordant rate less than 2%. The rate of inappropriate specimens for GYN cytology slides gradually decreased. CONCLUSIONS: The Continuous Quality Improvement program should be included in quality assurance programs. Moreover, these data can contribute to development of national cancer examination guidelines and facilitate cancer prevention and treatment.

Effect of Amount of Aluminum on the Performance of Si-Al Codeposited Anodes for Lithium Batteries.

Silicon is considered one of the most promising anode materials for high-performance Li-ion batteries due to its 4000 mAh/g theoretical specific capacity, relative abundance, low cost, and environmental benignity. However, silicon experiences a dramatic volume change (-300%) during full charge/discharge cycling, leading to severe capacity decay and poor cycling stability. Here, we report Si-Al codeposited anode material for Li-ion batteries. The Si-Al thin films were deposited by co-deposition from Si and Al target on nickel substrate. The composition of Si and Al in the film is estimated by energy-dispersive spectroscopy. The XRD and SEM analysis revealed that the Si-Al thin films were amorphous in structure. The electrochemical performance of the Si-Al thin film as anode material for lithium ion battery was investigated by the charge/discharge tests. Galvanostatic half-cell electrochemical measurements were conducted in between 0 mV to 2 V using a Li counter electrode, demonstrating that the Al rich Si-Al thin film achieved a good cycleability up to 100 cycles with a high capacity retention. Si-Al sample having 11.04% Al shows capacity 825 mAh/g over the 100 cycles.

Nonvolatile resistance switching on two-dimensional electron gas.

Two-dimensional electron gas (2DEG) at the complex oxide interfaces have brought about considerable interest for the application of the next-generation multifunctional oxide electronics due to the exotic properties that do not exist in the bulk. In this study, we report the integration of 2DEG into the nonvolatile resistance switching cell as a bottom electrode, where the metal-insulator transition of 2DEG by an external field serves to significantly reduce the OFF-state leakage current while enhancing the on/off ratio. Using the Pt/Ta2O5-y/Ta2O5-x/SrTiO3 heterostructure as a model system, we demonstrate the nonvolatile resistance switching memory cell with a large on/off ratio (>10(6)) and a low leakage current at the OFF state (∼10(-13) A). Beyond exploring nonvolatile memory, our work also provides an excellent framework for exploring the fundamental understanding of novel physics in which electronic and ionic processes are coupled in the complex heterostructures.

Electrochemical properties of Sn-substituted LiMn2O4 thin films prepared by radio-frequency magnetron sputtering.

The LiMn2O4 and LiSn0.0125Mn1975O4 thin films were grown on Pt/Ti/SiO2/Si (100) substrate by RF magnetron sputtering. To obtain the structural stability and good cycle performance, deposition parameters, namely working pressure, sputtering gas ratio of Ar and O2, post-annealing temperature were established. The structure and surface morphology of thin films were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The electrochemical properties were estimated by two electrode half-cell test with WBCS 3000 (Wonatech, Korea) at constant current rate of 1 C-rate. The Sn substituted LiMn2O4 thin film deposited at 10 mtorr with mixture of argon and oxygen (Ar/O2 = 3/1) and then annealed at 500 degrees C in O2 atmosphere showed good cycle performance. The Sn substituted LiMn2O4 thin films showed larger capacity of -30 microAh/microm-cm2 and higher cyclability than LiMn2O4 thin films.

Sensitivity enhancement of nanostructured SnO2 gas sensors fabricated using the glancing angle deposition method.

0.5 wt.% Pd-catalyzed SnO2 thin-film gas sensors with microstructures controlled on a nanometer scale were fabricated by an e-beam evaporator using the glancing angle deposition (GAD) method. After annealing at 500 degrees C for 1 h, the sensors produced were polycrystalline with a nanoporous, tilted columnar microstructure. The gas-sensing properties of these SnO2 sensors were measured in the concentration range of 1 to 5 ppm NO2 at 250 degrees C and of 10 to 50 ppm C2H5OH at 400 degrees C, respectively. The sensors fabricated by e-beam evaporation in combination with the GAD method showed much higher sensitivities than normally prepared sensors and exhibited rapid response times. The gas sensitivity (S = R(gas)/R(air)) of the SnO2 sensor using the GAD method was 43.4 for 5 ppm NO2 and 0.08 for 10 ppm C2H5OH, respectively. These sensors showed excellent sensitivities compared to the normal thin film sensors (S = 2 for 5 ppm NO2 and 0.92 for 10 ppm C2H5OH). We consider that the nanostructured sensors produced using the GAD process could be used to detect various gases emitted by automobiles and industrial installations.

A near single crystalline TiO2 nanohelix array: enhanced gas sensing performance and its application as a monolithically integrated electronic nose.

We present high performance gas sensors based on an array of near single crystalline TiO(2) nanohelices fabricated by rotating oblique angle deposition (OAD). The combination of large surface-to-volume ratio, extremely small size (<30 nm) comparable to the Debye length, a near single crystallinity of TiO(2) nanohelices, together with the unique top-and-bottom electrode configuration hugely improves the H(2)-sensing performance, including ∼10 times higher response at 50 ppm, approximately a factor of 5 lower detection limit, and much faster response time than the conventional TiO(2) thin film devices. Beyond such remarkable performance enhancement, the excellent compatibility of the OAD method compared with the conventional micro-fabrication technology opens a new avenue for monolithic integration of high-performance chemoresistive sensors to fabricate a simple, low cost, reliable, yet fully functional electronic nose and multi-functional smart chips for in situ environmental monitoring.