Stretchable anisotropic conductive film (S-ACF) for electrical interfacing in high-resolution stretchable circuits.

In stretchable electronics, high-resolution stretchable interfacing at a mild temperature is considered as a great challenge and has not been achieved yet. This study presents a stretchable anisotropic conductive film (S-ACF) that can electrically connect high-resolution stretchable circuit lines to other electrodes whether they are rigid, flexible, or stretchable. The key concepts of this study are (i) high-resolution (~50 µm) but low-contact resistance (0.2 ohm in 0.25 mm2) interfacing by periodically embedding conductive microparticles in thermoplastic film, (ii) low-temperature interfacing through the formation of chemical bonds between the S-ACF and the substrates, (iii) economical interfacing by selectively patterning the S-ACF, and (iv) direct interfacing of chips by using the adhesion of the thermoplastic matrix. We integrate light-emitting diodes on the patterned S-ACF and demonstrate stable light operation at large biaxial areal stretching (εxy = 70%).

Metabolic health is more closely associated with decrease in lung function than obesity.

OBJECTIVE: Previous studies have evaluated the link between metabolic syndrome and obesity with impaired lung function, however findings have been controversial. We aimed to compare lung function among subjects with different metabolic health and obesity status. METHODS: Total 10,071 participants were evaluated at the Health Promotion Center in Seoul St. Mary's Hospital between January 2012 and December 2014. Being metabolically healthy was defined as having fewer than three of the following risk factors: high blood pressure, high fasting blood glucose, high triglyceride, low high-density lipoprotein cholesterol and abdominal obesity. Obesity status was defined as body mass index (BMI) higher than 25 kg/m2. Analyses of pulmonary function were performed in four groups divided according to metabolic health and obesity: metabolically healthy non-obese (MHNO), metabolically health obese (MHO), metabolically unhealthy non-obese (MUHNO), and metabolically unhealthy obese (MUHO). RESULTS: Metabolically unhealthy subjects were more prone to decreased lung function compared with their metabolically healthy counterparts, regardless of obesity status. When multinomial logistic regression analysis was performed according to quartiles of forced vital capacity (FVC) or forced expiratory volume in 1 second (FEV1) (% pred), after adjusting for age, sex, and smoking status, odds ratio (OR) for the lowest FVC and FEV1 (% pred) quartiles were significantly higher in MUHO subjects (1.788 [95% CI, 1.531-2.089] and 1.603 [95% CI, 1.367-1.881]) and lower in MHO subjects (0.768 [95% CI, 0.654-0.902] and 0.826 [95% CI, 0.700-0.976]) with MHNO group as the reference, when OR for highest FVC and FEV1 quartiles were considered as 1.0. CONCLUSION: Metabolic health is more closely associated with impaired lung function than obesity.

The effect of photo-documentation of the ampulla on neoplasm detection rate during esophagogastroduodenoscopy.

BACKGROUND: A few studies have investigated quality indicators of esophagogastroduodenoscopy (EGD) for identifying upper gastrointestinal (GI) malignancy. The current study aimed to evaluate whether the rate of ampulla photo-documentation could be associated with the detection of upper GI neoplasms. METHODS: We used data from 111 962 asymptomatic patients who underwent EGD performed by 14 endoscopists at a health promotion center. The rate of ampulla photo-documentation was calculated by reviewing EGD photos archived during each endoscopist's first year of working at the center. The detection of neoplasms during a 7-year period was investigated. We examined the association between the rate of ampulla photo-documentation and the rate of neoplasm detection. RESULTS: The mean rate of ampulla photo-documentation was 49.0 % (range 13.7 % - 78.1 %) during endoscopists' first year of working at the center. Endoscopists' rates of ampulla photo-documentation significantly correlated with the detection of total neoplasms (R2 = 0.57, P = 0.03) and small neoplasms (R2 = 0.58, P = 0.03). There was a significant difference in the detection rates of upper GI neoplasms between high (n = 7) and low (n = 7) ampulla observers (odds ratio [OR] 1.31, 95 % confidence interval [CI] 1.03 - 1.68; P = 0.03). The ampulla photo-documentation rate of each endoscopist significantly correlated with the examination time for a normal EGD (R2 = 0.55; P = 0.04). In multivariate analysis, high ampulla photo-documentation rate was a predictor of neoplasm detection (OR 1.33, 95 %CI 1.03 - 1.70). CONCLUSIONS: The ampulla photo-documentation rate was significantly associated with the detection rate for both total and small upper GI neoplasms. Ampulla photo-documentation should be considered as a quality indicator of EGD.

Continuous-wave THz vector imaging system utilizing two-tone signal generation and self-mixing detection.

We propose and demonstrate a continuous-wave vector THz imaging system utilizing a photonic generation of two-tone THz signals and self-mixing detection. The proposed system measures amplitude and phase information simultaneously without the local oscillator reference or phase rotation scheme that is required for heterodyne or homodyne detection. In addition, 2π phase ambiguity that occurs when the sample is thicker than the wavelength of THz radiation can be avoided. In this work, THz signal having two frequency components was generated with a uni-traveling-carrier photodiode and electro-optic modulator on the emitter side and detected with a Schottky barrier diode detector used as a self-mixer on the receiver side. The proposed THz vector imaging system exhibited a 50-dB signal to noise ratio and 0.012-rad phase fluctuation with 100-µs integration time at 325-GHz. With the system, we demonstrate two-dimensional THz phase contrast imaging. Considering the recent use of two-dimensional arrays of Schottky barrier diodes as a THz image sensor, the proposed system is greatly advantageous for realizing a real-time THz vector imaging system due to its simple receiver configuration.

Longer Observation Time Increases Proportion of Neoplasms Detected by Esophagogastroduodenoscopy.

BACKGROUND & AIMS: Esophagogastroduodenoscopy (EGD) is commonly used to detect upper gastrointestinal (GI) neoplasms. However, there is little evidence that longer examination time increases rate of detection of upper GI neoplasia. We investigated the association between length of time spent performing a normal screening EGD and rate of neoplasm detection. METHODS: We performed a retrospective analysis of data from 111,962 subjects who underwent EGD as part of a comprehensive health-screening program from January 2009 to December 2015 in Korea. Endoscopy findings were extracted from reports prepared by 14 board-certified endoscopists. Endoscopists were classified as fast or slow based on their mean examination time for a normal EGD without biopsy during their first year of the study. All endoscopists used the same endoscopy unit. We obtained findings from histologic analyses of GI biopsies from patient records; positive findings were defined as the detection of neoplasms (esophageal, gastric, or duodenal lesions). We examined the association between examination time and proportions of neoplasms detected. The primary outcome measure was the rate of neoplasm detection for each endoscopist (total number of neoplastic lesions detected divided by the number of subjects screened) and as the proportion of subjects with at least 1 neoplastic lesion. RESULTS: The mean examination time was 2 minutes 53 seconds. Using 3 minutes as a cutoff, we classified 8 endoscopists as fast (mean duration, 2:38 ± 0:21 minutes) and 6 endoscopists as slow (mean duration, 3:25 ± 0:19 minutes). Each endoscopist's mean examination time correlated with their rate of neoplasm detection (R2 = 0.54; P = .046). Fast endoscopists identified neoplasms in the upper GI tract in 0.20% of patients, whereas slow endoscopists identified these in 0.28% of patients (P = .0054). The frequency of endoscopic biopsy varied among endoscopists (range, 6.9%-27.8%) and correlated with rate of neoplasm detection (R2 = 0.76; P = .0015). On multivariable analysis, slow endoscopists were more likely to detect gastric adenomas or carcinomas than fast endoscopists (odds ratio, 1.52; 95% CI, 1.17-1.97). CONCLUSIONS: In a retrospective analysis of data from more than 100,000 subjects who underwent EGD in a screening program, we found slow endoscopists detected a higher proportion of neoplasms than fast endoscopists. Examination time is therefore a useful indicator of quality for EGD.

Laminated metamaterial flat lens at millimeter-wave frequencies.

A flat and thin shape is obviously advantageous not only in terms of reducing the volume of a device, but also in handling and using it. Particularly, laminating or stacking flat devices is an intuitive and straightforward way of tailoring performance and functions. Here, we experimentally demonstrated a laminated flat lens for millimeter-wave frequencies that is based on split-ring resonators (SRRs) composed of multiple layers with different and/or identical index profiles and that exhibits characteristics that are linear combinations of those of the individual lenses. Since the characteristics of the lenses of each layer are preserved regardless of the neighbouring layers, the desired functionalities can be easily implemented simply by laminating elementary lenses designed already. When we laminated two lenses designed for bending or focusing incoming waves at 120 GHz, we clearly observed that the outgoing waves collimated and bended as desired.

Compact and stable THz vector spectroscopy using silicon photonics technology.

We present a compact and stable terahertz (THz) vector spectroscopy system using silicon photonics technology. A silicon-based integrated phase control circuit greatly reduces the physical size of the continuous-wave THz spectroscopy system and enhances environmental phase stability. Differential lightwave phase control using two carrier-injection electro-optic modulators enables fast and linear phase sweeps of THz-waves. Using the silicon-photonic circuit, we demonstrate a THz vector spectrometer; the dynamic ranges are 65 and 35 dB at 300 GHz and 1 THz with 1-ms integration time and phase variation is less than ± 10° without thermal packaging.

CW-THz vector spectroscopy and imaging system based on 1.55-µm fiber-optics.

We present a continuous-wave terahertz (THz) vector spectroscopy and imaging system based on a 1.5-µm fiber optic uni-traveling-carrier photodiode and InGaAs photo-conductive receiver. Using electro-optic (EO) phase modulators for THz phase control with shortened optical paths, the system achieves fast vector measurement with effective phase stabilization. Dynamic ranges of 100 dB · Hz and 75 dB · Hz at 300 GHz and 1 THz, and phase stability of 1.5° per minute are obtained. With the simultaneous measurement of absorbance and relative permittivity, we demonstrate non-destructive analyses of pharmaceutical cocrystals inside tablets within a few minutes.

Total cholesterol and lipoprotein composition are associated with dry eye disease in Korean women.

BACKGROUND: This study aimed to determine the relationship between dyslipidemia and dry eye disease (DED) in a Korean population. METHODS: This population-based study enrolled 5,627 adults (aged >19 years) who were participating in the first year of the fifth annual Korea National Health and Nutrition Examination Survey from 2010 to 2011. Clinically diagnosed DED and its symptoms were surveyed, and biochemical blood analysis data were collected. Dyslipidemia was defined as any of the following: hypercholesterolemia (total cholesterol > 200 mg/dL), hypertriglyceridemia (triglyceride > 150 mg/dL), low levels of high-density lipoprotein (<40 mg/dL), or high levels of low-density lipoprotein (>100 mg/dL). RESULTS: After adjusting for demographics (age and body mass index), lifestyle (smoking, drinking, exercise, and residential district), and medical factors (diabetes, hypertension, previous ophthalmic surgery, menopause, and rheumatologic disease), elevated serum cholesterol level was found to be associated with increased likelihood of DED (odds ratio, 1.77; 95% confidence interval, 1.127-2.78) in women. CONCLUSIONS: DED in a Korean population was found to be associated with high serum cholesterol levelsThe results of this study highlight the significance of eye examinations and independent lipid profile monitoring in patients with dyslipidemia because of its possible correlation with DED progression.

Generation of frequency-modulated sub-terahertz signal using microwave photonic technique.

We present a photonic technique for generating a frequency- modulated sub-terahertz signal for non-destructive or noninvasive sensing and imaging applications. Large frequency deviation was achieved by using optical phase modulation and heterodyne photomixing with an uni-travelling photodetector. The operation principle is theoretically derived and explained. In addition, the generation of 350-GHz frequency- modulated sub-terahertz signal with 6.7-GHz frequency deviation is experimentally demonstrated, and the possibility of frequencies up to 1 THz and wider frequency deviations is discussed.

An all-optical frequency up-converter utilizing four-wave mixing in a semiconductor optical amplifier for sub-carrier multiplexed radio-over-fiber applications.

A novel all-optical frequency up-converter utilizing four-wave mixing (FWM) in a semiconductor optical amplifier (SOA) was proposed and experimentally demonstrated. The frequency up-converter converted an optical intermediate frequency (IF) signal (f(IF) = 2.5 GHz) to an optical radio frequency (RF) signal (f(RF) = 35 and 40 GHz) through mixing with an optical local oscillator (LO) signal (f(LO) = 37.5 GHz). The up-converter showed positive conversion efficiency of 5.77 dB for the optical IF power of -22 dBm and the optical LO power of -13 dBm. This scheme showed broad bandwidths with respect to both LO and IF frequencies. The up-converter showed a phase noise of -84.5 dBc/Hz for the LO frequency of 37.5 GHz (f(LO)) and the offset frequency of 10 kHz after the frequency up-conversion.

Generation of two-mode optical signals with broadband frequency tunability and low spurious signal level.

For continuous millimeter and terahertz-wave applications, a two-mode optical signal generation technique that uses two arrayed waveguide gratings and two optical switch units is presented. In addition to easy and fast operation, this scheme offers broadband frequency tunability and high signal purity with a low spurious mode level. Mode spacing, which corresponds to the frequency of the generated MM/THz-wave signal after photomixing, was successfully swept in the range of 200 ~ 550 GHz and the optical spurious mode suppression ratio higher than 25 dBc was achieved. In addition, spurious modes characteristics were investigated by using second harmonic generation (SHG) autocorrelation methods for several frequencies.

Effects of selective cyclooxygenase-2 inhibitor and non-selective NSAIDs on Helicobacter pylori-induced gastritis in Mongolian gerbils.

BACKGROUND: It is still a point of controversy whether Helicobacter pylori-infected patients are more likely to develop mucosal damage while taking NSAIDs. Selective cyclooxygenase (COX-2) inhibitors may be associated with less severe gastric mucosal damage than conventional NSAIDs, but this association is undefined in H. pylori-induced gastritis. The aim of this study was to evaluate the effects of selective COX-2 and nonselective NSAIDs on H. pylori-induced gastritis. METHODS: After intragastric administration of indomethacin, NS-398 or vehicle alone, once daily for 5 days in H. pylori-infected and uninfected Mongolian gerbils, we evaluated gastric mucosal damage, inflammatory cell infiltration and prostaglandin E2 (PGE2) concentration. We investigated whether H. pylori infection induced the COX-2 expression. RESULTS: In H. pylori-uninfected groups, the indomethacin-treated group showed the highest mucosal damage score and the lowest PGE2 concentration. There was no difference in mucosal damage scores and PGE2 concentration between NS-398 and vehicle-alone treated group. In H. pylori-infected groups, there was no difference in mucosal damage scores, irrespective of the type of drugs administered. The indomethacin-treated group showed the lowest PGE2 concentration, similar to that of the NS-398 and vehicle-alone treated groups, both without H. pylori infection. Gastric neutrophil and monocyte infiltration scores were higher in H. pylori-infected groups than in uninfected groups. However, there was no difference in these scores according to the type of drugs administered, within H. pylori-infected or uninfected groups. COX-2 protein expression was observed in H. pylori-infected Mongolian gerbils but not in uninfected ones. CONCLUSIONS: Our animal study showed that H. pylori infection induced COX-2 expression and increased prostaglandin concentration. Administration of NSAIDs decreased the prostaglandin concentration, but did not increase mucosal damage in H. pylori-induced gastritis. Selective COX-2 inhibitors, instead of conventional NSAIDs, had no beneficial effect on preventing mucosal damage in H. pylori-induced gastritis.