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The Relationship between Cold Exposure and Hypertension: Joon-Youn KIM, et al. Department of Preventive Medicine, Medical College, Dong-A University, Korea-This study was performed to determine whether there was any relationship between cold exposure and hypertension, and to evaluate risk factors affecting hypertension in cold-exposed workers. In 11 refrigeration industries, 68 male workers working in cold areas more than once per day were selected as the cold-exposed group, and 68 workers not exposed to cold were selected as the control group. The questionnaire survey, clinical and laboratory tests were performed. Systolic and diastolic blood pressures were significantly higher in the cold-exposed group, and body core temperature was significantly lower in the cold-exposed group (p<0.05). In logistic regression analysis, age, cold exposure severity and milk intake were significant variables affecting hypertension in coldexposed workers, whose odd ratios were 5.204 (95% CI 1.440-18.812), 2.674 (95% CI 1.080-6.618), and 0.364 (95% CI 0.141-0.942), respectively. Cold exposure was a risk factor for hypertension, and risk factors affecting hypertension in cold exposed workers were age, cold exposure severity, and milk intake. Therefore, cold exposed workers should minimize cold exposure time as much as possible, and ingest foods containing calcium such as milk. In particular, old workers working in cold areas should check their blood pressure and electrocardiogram periodically. (J Occup Health 2003; 45: 300-306)

A new diterpenoid quinone, agastaquinone [1], was isolated from the roots of Agastache rugosa. An oxime derivative [2] of agastaquinone was prepared with hydroxylamine hydrochloride. The structure of agastaquinone [1] was established as 7-hydroxy-12-methoxy-20-norabieta-1,5(10),6,8,12-pentaene-3,11,14- trione by spectroscopic techniques. Compounds 1 and 2 showed nonspecific cytotoxic activities against several human cancer cell lines in vitro (A549, SK-OV-3, SK-MEL-2, XF498, and HCT15).

ObjectiveThe present study analyzed relationship of workplace violence and perpetrators of violence on sleep disturbance among wage workers in Korea.MethodsThe present study used data from the 4th Korean Working Conditions Survey (KWCS) of 2014 in selecting a total of 25,138wage workers as the study population, which excluded those who failed or refused to respond to questions required for the present study. The workplace violence experience group included people who satisfied at least one of six relevant criteria (verbal abuse, unwanted sexual attention, threatening or humiliating behavior, physical violence, bullying/harassment, and sexual harassment) and the group was divided according to whether the perpetrator of violence was a client or colleague. Presence of sleep disturbance was determined based on subjective symptoms felt within the past 12 months by each individual. A multiple logistic regression analysis was performed to identify the effects on sleep distance according to general, occupational, and psychosocial characteristics, as well as the types of workplace violence and perpetrators of violence.ResultsWorkplace violence was found as a factor affecting sleep disturbance (OR = 3.773, 95 % CI = 3.058–4.655), and with respect to perpetrators of violence, complaint of sleep disturbance symptoms was higher when the perpetrator was a colleague or boss (OR = 5.688, 95 % CI 4.189–7.723) than a client (OR = 2.992, 95 % CI 2.301–3.890).ConclusionWorkplace violence had an effect on occurrence of sleep disturbance and when the perpetrators of violence was a boss or colleague at work, the risk for symptoms such as sleep disturbance increased, which indicated the need for appropriate intervention from a workplace healthcare perspective, including preventive education of workplace violence among employees.

We demonstrate high speed scanning of a time-domain terahertz pulse by a rotary optical delay line (RODL) incorporated into a photoconductive antenna based terahertz system. The delay line of RODL consists of six rotating convex reflective blades with a rotating speed controlled for a wide range of scan repetition rates. It can perform path length scans of 2.1 cm at a scanning speed of 8.4 m/s while maintaining linearity. The comparison of the terahertz temporal waveform and the frequency spectrum measured by using the RODL and a linear stage optical delay line confirms the linearity of the RODL up to 140 ps at high scan repetition rates of 400 scan/s. A high signal-to-noise ratio, up to a few thousand, can be obtained by averaging multiple terahertz pulses at a high scan speed.

Continuous-wave (CW) terahertz (THz) imaging with a horn antenna is proposed to enhance the spatial resolution of a THz imaging system. The attached waveguide that is smaller than the wavelength can easily increase the spatial resolution, and the optimized horn flare can significantly increase the transmission power. Consequentially, transmission THz images of a phantom obtained by the amplitude signal using a 0.2 THz wave reveal that the spatial resolution is achieved up to 500 μm. Also, the transmitted power is increased up to 6 times higher compared to the pinhole aperture. The feasibility of CW THz imaging with a horn antenna is demonstrated by the inspection of the organic samples inside food resulting in a relatively high sensitivity for soft organic samples compared with the sensitivity of X-ray imaging to this kind of samples.

BackgroundHealth problems in shift workers vary including obesity acting as a risk factor in cerebrovascular diseases. Recent studies have commonly determined the prevalence of obesity in shift workers on the basis of body mass index. The accuracy of BMI for diagnosing obesity are still limited apparently. Consequently, this study aimed to determine the relationship between shift work and obesity according to the total body fat percentage in Korean wage workers.MethodsFrom the Fourth and the Fifth Korea National Health and Nutrition Examination Survey (2008–2011), after military personnel were excluded, a total of 2952 wage workers (20 ≤ age ≤ 65) whose current jobs were their longest jobs were selected as subjects of the study. The total body fat percentage was used to determine the obesity standards (≥25.7 % in males and ≥36.0 % in females). The subjects were divided into groups by gender and work type (manual vs non-manual), and chi-squared test was used to evaluate the relationship between socio-economic, health behavior, and work-related factors, on the one hand, and obesity, on the other. In addition, multivariate logistic regression analysis was performed to examine the effects of shift work on obesity.ResultsWhen other factors were controlled for, the risk of obesity in shift work showed a statistically significant increase (odds ratio = 1.779, 95 % confidence interval = 1.050-3.015) in the male manual worker group. However, there were no significant results in the male non-manual and female worker groups.ConclusionShift work was related to a higher risk of obesity in the Korean male manual worker group.

We report the first measurement of terahertz pulse using a rotary optical delay line (RODL). The delay line uses a rotating reflective surface that gives a linear delay length with respect to the rotation angle. Operation principles and the profile of the reflective surface are examined and the optical path as a function of the radius and the rotating angle is calculated. A comparison of the temporal waveform and frequency spectrum obtained by using the RODL and the linear stage optical delay line (LODL) confirms that the linearity of the RODL is up to 500 ps corresponding to a delay scan length of 7.5 cm, and the difference in time delay is less than 0.2 ps. The RODL is suitable for the high-speed scanning of terahertz pulses up to 400 Hz.