Mental health and current issues of migrant workers in Japan: A cross-sectional study of Vietnamese workers.

Background: Over the past 5 years, the number of Vietnamese migrant workers in Japan has grown rapidly to become the largest group of migrant workers in the country. They hold various statuses of residence and are subjected to multifactorial stressors.

Aims: The current study's aim is to investigate the association between psychological distress experienced by Vietnamese workers and their work environment.

Burn and cut injuries related to job stress among kitchen workers in Japan.

To clarify the correlation between kitchen work-related burns and cuts and job stress, a self-administered questionnaire survey was conducted involving 991 kitchen workers among 126 kitchen facilities. The demographics, condition of burns and cuts, job stress with the Brief Job Stress Questionnaire (BJSQ), health condition, and work-related and environmental factors were surveyed. Multiple logistic regression models and trend tests were used according to quartiles (Q1, Q2, Q3, and Q4) of each sub-scale BJSQ.

Risk factors for frequent work-related burn and cut injuries and low back pain among commercial kitchen workers in Japan.

This study investigated risk factors for frequent work-related burn and cut injuries and low back pain (LBP) among kitchen workers including personal, work-related and environmental factors. Subjects were 991 kitchen workers in 103 schools, 17 hospitals and nursing homes, and 6 restaurants in central Japan. A cross-sectional survey was carried out using a structured self-administered questionnaire.

Transmission over large-core few-mode photonic crystal fiber using distance-independent modal dispersion compensation technique.

We propose a transmission distance-independent technique for modal dispersion compensation over few-mode fiber that uses a single-input multiple-output configuration and adaptive equalization. Our technique can compensate for the modal dispersion of a signal with 1-tap FIR filters regardless of the amount of modal delay difference, and enables us to utilize fiber with a large core and few modes as a long-haul transmission line. We also show numerically the advantage of few-mode photonic crystal fiber (PCF) for realizing a larger effective area (A(eff)), and finally we report a transmission over a large-core two-mode PCF with A(eff)>280 μm(2).

Coherent optical MIMO transmission over 20 km GI multi-mode fiber by using digital coherent receiver with mode convergence unit.

We describe a coherent optical MIMO transmission experiment that employs a digital coherent receiver with a mode convergence unit, which converges higher-order mode light into the fundamental mode while maintaining the phase and amplitude information of the higher-order mode. The coherent optical MIMO transmission of two 10 Gbit/s BPSK signals over 20 km of graded-index multi-mode fiber was successfully achieved by using this mode convergence unit. We also show numerically that multi channel signals for a coherent optical MIMO transmission can be recovered by employing sufficient mode diversity, even if mode conversion occurs in the transmission fiber.

The effects of work environments on thermal strain on workers in commercial kitchens.

The purpose of this study was to clarify the effect of working environments of different kinds of commercial kitchens on the thermal strain of kitchen workers. This study design was cross-sectional study, and data collection was performed during busy time in commercial kitchen from August to September 2006. The research subjects were 8 institutions, involving 7 cookers, and 16 men.

Hole-assisted dual concentric core fiber with ultralarge negative dispersion coefficient of -13,200 ps/nm/km.

We propose a dual concentric core fiber (DCCF) with six homogeneous air holes, designed to realize a large negative dispersion coefficient. We clarify numerically that the dispersion property of the proposed DCCF can be controlled flexibly by adjusting the air-hole structure, and we realize the largest reported negative dispersion of -13,200 ps/nm/km experimentally.

Prevalence of self-reported finger deformations and occupational risk factors among professional cooks: a cross-sectional study.

Background: Previous studies have pointed out that the school lunch workers in Japan are suffering from work-related disorders including finger deformations. The purpose of this study was to investigate the prevalence of self-reported finger deformations and the association with job-related risk factors.

Methods: A cross-sectional questionnaire study of 5,719 subjects (response rate: 81%, 982 men and 4,737 women) was undertaken during September 2003 to February 2004.

Group velocity dispersion measurement method using sinusoidally phase-modulated continuous wave light based on cyclic nature of optical waveform change by group velocity dispersion.

We show that any optical pulse train recovers its original waveform after passing through a group velocity dispersion (GVD) device when the total GVD value of the device is equal to an integral multiple of 1/(2πf(rep)(2)), where f(rep) is the repetition rate of the optical pulse train. In addition, we detail our proposed GVD measurement method, or optical phase-modulation (PM) method, which utilizes a sinusoidally PM continuous wave (CW) light as a probe light. The total GVD B(2) of a device under test (DUT) is derived by using a very simple equation, |B(2)|=1/(2πf(null)(2)), where f(null) is the smallest modulation frequency at which the sinusoidally PM light becomes CW light again after passing through the DUT.

Prevalence and risk factors of low back pain among Thai and Myanmar migrant seafood processing factory workers in Samut Sakorn Province, Thailand.

This study assessed the prevalence of low back pain (LBP) and investigated risk factors for LBP among seafood processing factory workers in Thailand including migrant workers. The subjects were Thai and Myanmar workers in the typical seafood processing factory. A cross-sectional study was carried out with a self-administered questionnaire.

Observation of a propagation mode of a fiber fuse with a long-period damage track in hole-assisted fiber.

We examined the fiber-fuse propagation characteristics in hole-assisted fibers (HAFs) when the diameter of an inscribed circle linking the air holes was almost the same as the diameter of the melted area caused by the fiber fuse. We observed a new propagation mode for the fiber fuse in HAF with a damage track whose period was approximately 30 times longer than that in conventional single-mode fiber. We also made the first observation of a new threshold power (upper threshold) for the fiber fuse.

Evaluation of subjective thermal strain in different kitchen working environments using subjective judgment scales.

To elucidate the subjective thermal strain of workers in kitchen working environments, we performed a cross-sectional study involving 991 workers in 126 kitchen facilities in Japan, using a self-reporting questionnaire survey and subjective judgment scales (SJS). The ambient temperature, mean radiant temperature (MRT), and wet-bulb globe temperature (WBGT) index were measured in 10 kitchen facilities of the 126 kitchens. The association of SJS with the types of kitchen was estimated by multiple logistic regression models.

Layer-by-layer assembled thin films composed of carboxyl-terminated poly(amidoamine) dendrimer as a pH-sensitive nano-device.

Dendrimer-containing multilayer thin films have successfully been prepared by a layer-by-layer deposition of carboxyl-terminated poly(amidoamine) dendrimer (PAMAM-COOH) and poly(methacrylic acid) (PMA) on a solid surface at pH 4.0, while the multilayer film did not form at pH 7.0.

Prevalence and risk factors for low back pain among professional cooks working in school lunch services.

Background: The prevalence of self-reported low back pain among professional cooks was estimated to examine the effects of daily life conditions, job-related factors, and psychological factors on this disorder.

Methods: Data was collected using a mailed self-administered questionnaire.

Results: Of 7100 cooks, 5835 (82%) replied to the questionnaire, including 1010 men and 4825 women.