Chang Hyun Lee

Radiation exposure to the patient has become a concern for the radiologist in the multidetector computed tomography (CT) era. With the introduction of faster multidetector CT scanners, various techniques have been developed to reduce the radiation dose to the patient; one method is automatic exposure control (AEC). AEC systems make use of different types of control, including patient-size AEC, z-axis AEC, rotational or angular AEC, or a combination of two or more of these types. AEC systems oper

Background: It is well known that air pollution causes respiratory morbidity and mortality by inducing airway inflammation. However, whether long-term exposure to air pollution is associated with increased incidence of chronic obstructive pulmonary disease (COPD) is controversial. Methods: We conducted a systematic review and meta-analysis with a random-effects model to calculate the pooled risk estimates of COPD development per 10 μg/m3 increase in individual air pollutants. PubMed, Embase, and

A novel SONOS structure of SiO/sub 2//SiN/Al/sub 2/O/sub 3/ (SANOS) with TaN metal gate is for the first time proposed for the next generation non-volatile memory technology. When TaN metal gate is applied for the SANOS instead of commonly used n+ poly-Si, the unwanted backward Fowler-Nordheim tunneling current of electrons through the top oxide is significantly suppressed owing to its higher work function and better compatibility with high k dielectrics. As a result, the program/erase speed is

Ultrasonographic findings suggesting malignancy should be preferentially considered as indicators for FNA, regardless of size, in nonpalpable thyroid nodules. However, extracapsular invasion and lymph node metastasis are closely related to the size of the thyroid nodule.

In candidates for metastatectomy, reading with the aid of either CAD or MIP significantly improved the detection of malignant nodules compared with using thin-section CT alone.

Saline chase prolongs the duration of plateau and delays peak enhancement of the pulmonary artery and aorta. Saline chase injected at half the rate of contrast medium injection allowed more uniform and prolonged plateau contrast enhancement than other protocols.

With our study protocol of a 30-second injection and 10-second saline flush, the optimal temporal window to achieve pulmonary artery enhancement greater than 200 H was from 16 seconds to 41 seconds after the start of the injection.

Cell competition, the conditional loss of viable genotypes only when surrounded by other cells, is a phenomenon observed in certain genetic mosaic conditions. We conducted a chemical mutagenesis and screen to recover new mutations that affect cell competition between wild-type and RpS3 heterozygous cells. Mutations were identified by whole-genome sequencing, making use of software tools that greatly facilitate the distinction between newly induced mutations and other sources of apparent sequence

Micro-CT scores and pathologic scores were found to be well correlated by in vivo and postmortem micro-CT. Although agreements between in vivo and postmortem micro-CT were significant, the confidence levels for fibrosis-related CT findings were significantly higher by postmortem micro-CT.

The symmetric inversion-type S/D structure has been employed for achieving available program disturbance for scaled NAND flash memory beyond sub-40 nm node. The inversion S/D structure enables the channel doping to be reduced due to non-existence of n-lateral diffusion and it suppresses charge sharing between program-inhibit channels, resulting in superior program disturbance. Moreover, the cells show better current drivability in the technology node less than 50 nm by more successful working of

The overall radiologists' performance of detecting lung nodules was improved significantly with the use of CAD, whereas no statistical significance was observed for the detection of lung cancers. The use of CAD, however, contributed to the detection of additional lung cancers for less experienced readers.