Harmonically mode-locked laser pulse accumulation in a self-resonating optical cavity.

Optical enhancement cavities enabling laser pulses to be coherently stacked in free space are used in several applications to enhance accessible optical power. In this study, we develop an optical cavity that accumulates harmonically mode-locked laser pulses with a self-resonating mechanism for X-ray sources based on laser-Compton scattering. In particular, a Fabry-Perot cavity composed of 99% reflectance mirrors maintained the optical resonance in a feedback-free fashion for more than half an hour and automatically resumed the accumulation even if the laser oscillation was suspended. In contrast to conventional optical enhancement cavity systems with a dedicated feedback controller, this characteristic is highly beneficial in practical applications, such as for laser-Compton scattering X-ray sources. Lastly, upscaling and adoption of the proposed system might improve the operability and equipment use of laser Compton-scattering X-ray sources.

Ultrafast time-resolved single-shot birefringence microscopy for laser-induced anisotropy.

The interaction between ultrashort laser pulses and materials in the ultrafast time domain, especially regarding the effect of laser polarization, has attracted much attention. In this study, ultrafast time-resolved single-shot birefringence microscopy is performed to observe laser-induced anisotropy. The birefringences of the optical Kerr effect and laser-induced anisotropic nanostructures by femtosecond laser pulses in silica glass are measured, and their slow axis is confirmed to correspond to the linear polarization angle of the pump light. We discuss the time variations of these birefringences in the picosecond time domain.

Independent contribution of optical attenuation length in ultrafast laser-induced structural change.

Although laser irradiation with femtosecond pulses is known to generate crystallization and morphological changes, the contribution of optical parameters to material changes is still in discussion. Here, we compare two structures irradiated near Si-L2,3 edges by an extreme ultraviolet femtosecond pulse. Our result implies that, despite the femtosecond irradiation regime, these values of the optical attenuation length between the wavelengths of 10.3-nm and 13.5-nm differ by one order of magnitude. From the structural comparison, the original crystalline state was maintained upon irradiation at 13.5-nm, on the other hand, transition to an amorphous state occurred at 10.3-nm. The difference in optical attenuation length directly influence to the decision of material crystallization or morphological changes, even if the irradiation condition is under the femtosecond regime and same pulse duration. Our result reveals the contribution of optical attenuation length in ultrafast laser-induced structural change.

Soft x-ray laser beamline for surface processing and damage studies.

We have developed a soft x-ray laser (SXRL) beamline equipped with an intensity monitor dedicated to ablation study such as surface processing and damage formation. The SXRL beam having a wavelength of 13.9 nm, pulse width of 7 ps, and pulse energy of around 200 nJ is generated from Ag plasma mediums using an oscillator-amplifier configuration. The SXRL beam is focused onto the sample surface by the Mo/Si multilayer coated spherical mirror. To get the correct irradiation energy/fluence, an intensity monitor composed of a Mo/Si multilayer beam splitter and an x-ray charge-coupled device camera has been installed in the beamline. The Mo/Si multilayer beam splitter has a large polarization dependence in the reflectivity around the incident angle of 45°. However, by evaluating the relationship between reflectivity and transmittance of the beam splitter appropriately, the irradiation energy onto the sample surface can be derived from the energy acquired by the intensity monitor. This SXRL beamline is available to not only the ablation phenomena but also the performance evaluation of soft x-ray optics and resists.

[Current issues in access to care services for the elderly in Japan focusing on special permanent residents and foreign-born Japanese: A report by the Monitoring Report Committee of the Japanese Society of Public Health].

　Japan is currently one of the countries with a long life expectancy, in which a great number of older people need care for their daily living. Japan has become increasingly internationalized due to an increase in foreigners and international marriages. As the number of elderly foreigners and foreign-born Japanese increase, older adults who do not use Japanese as their first language will need more opportunities to receive care.　We examined characteristics such as country of origin, language spoken, lifestyle, living environment, and cultural background of elderly people who were either foreign permanent residents living in Japan or foreign-born Japanese (hereinafter referred to as elderly with an international background, in short, EIB) receiving care support. Ichushi-web, a medical literature database, was used [last search date: June 2, 2018]. These searches extracted 205 papers. After the first and second extraction procedures, only two papers matched this theme. These two reports were for Korean residents in Japan, so-called special permanent residents, and repatriates from China and their spouses, many of whom were aged 75 years old and above.　The number of permanent residents in Japan who speak a foreign language as their first language is increasing. Inhibition of communication between EIB and healthcare welfare service providers is expected to be an obstacle while accessing care support services. For this reason, we must provide them with information related to Japanese healthcare services. Medical interpretation efforts are scattered and the response to EIB in the event of disasters has been discussed. From the perspective of multicultural coexistence, it is necessary to provide long-term care insurance services and medical services to EIB. Such efforts may include development and sharing of tools and the placement of staff who can communicate with non-Japanese speakers. Staff must also understand various illness- and health awareness-related issues.　In the future, considering the increasing number of EIB who may require care services, we must consider cultural backgrounds and language diversification for EIB. These issues require clarification and development of acceptable solutions.

Long-term course of Crohn's disease in Japan: Incidence of complications, cumulative rate of initial surgery, and risk factors at diagnosis for initial surgery.

BACKGROUND AND AIMS: Intestinal complications of stenosis or fistula may occur during the course of Crohn's disease (CD), and surgery is performed in a fair number of patients. The risk factors for initial surgery in a Japanese hospital-based cohort of CD patients were evaluated. METHODS: This study was a single-center, retrospective, cohort study. The subjects were 520 patients who underwent inpatient and outpatient treatment at our hospital, had a definitive diagnosis of CD, and no previous surgery. Three parameters were investigated: (i) cumulative incidence of stenosis and fistula; (ii) cumulative rate of initial surgery for each disease type; and (iii) risk factors at diagnosis for initial surgery. RESULTS: (i) Stenosis and fistula increased with time, with stenosis or fistula appearing in about half of the patients after 5 years. (ii) The cumulative rate of initial surgery was about 50% after 10 years. (iii) The patient factors at diagnosis of current smoker, upper gastrointestinal disease, stricturing, penetrating, moderate to severe stenosis of the jejunum, moderate to severe stenosis of the ileum, and moderate to severe stenosis of the terminal ileum were risk factors for initial surgery. CONCLUSIONS: Stenosis or fistula appeared in about half of the patients after 5 years from diagnosis. When upper gastrointestinal disease or complicated small intestinal lesions are seen at the time of diagnosis, the cumulative rate of initial surgery is significantly higher.

Second peak in the distribution of age at onset of ulcerative colitis in relation to smoking cessation.

BACKGROUND AND AIM: The prevalence of ulcerative colitis (UC) is increasing steadily in Japan. In Western countries, a bimodal distribution, with UC onset peaks in youth and middle age, is observed, and smoking cessation is reported as a risk factor for UC. However, there are few reports on a bimodal distribution of onset age among Japanese patients. Therefore, the distribution of onset age and factors related to late onset (i.e. onset at 50 years old or later) were investigated in UC patients in Japan. METHODS: A questionnaire survey of UC patients was conducted to investigate the distribution of the age of onset and factors that may be related to UC onset in a Japanese university hospital. RESULTS: Among 465 UC patients, 343 patients responded. In the distribution of onset age, a large peak was seen in patients aged 10-20s, and small peaks were seen at age 40-44 years and then in 50-60s. In addition, the onset age was older in the UC patients diagnosed in 2001 or later than in those diagnosed in 2000 or earlier. Late onset was more common among the UC patients diagnosed in 2001 or later (vs 2000 or earlier: interaction odds ratio = 4.98, 95% CI: 2.21-11.25, P < 0.01) and among former smokers (vs never-smokers: interaction odds ratio = 2.93, 95% CI: 1.40-6.14, P < 0.01) on multivariate analysis. CONCLUSIONS: Similar to UC patients in Western countries, a bimodal distribution of onset age was also observed in Japanese UC patients, and smoking cessation may partly contribute to the increase in late-onset UC patients in recent years in Japan.

Depression among family caregivers of community-dwelling older people who used services under the Long Term Care Insurance program: a large-scale population-based study in Japan.

OBJECTIVE: To identify predictors for depression among family caregivers of community-dwelling older people under the Long Term Care Insurance (LTCI) program in Japan through a large-scale population-based survey. METHOD: All 5938 older people with disabilities, using domiciliary services under the LTCI in the city of Toyama, and their family caregivers participated in this study. Caregiver depression was defined as scores of ≥16 on the Center for Epidemiological Studies Depression Scale (CES-D). Other caregiver measures included age, sex, hours spent caregiving, relationship to the care recipient, income adequacy, living arrangement, self-rated health, and work status. Care recipient measures included age, sex, level of functional disability, and severity of dementia. The data from 4128 pairs of the care recipients and their family caregivers were eligible for further analyses. A multiple logistic regression analysis was used to examine the predictors associated with being at risk of clinical depression (CES-D of ≥16). RESULTS: Overall, 34.2% of caregivers scored ≥16 on the CES-D. The independent predictors for depression by logistic regression analysis were six caregiver characteristics (female, income inadequacy, longer hours spent caregiving, worse subjective health, and co-residence with the care recipient) and one care-recipient characteristic (moderate dementia). CONCLUSION: This is one of the first population-based examinations of caregivers of older people who are enrolled in a national service system that provides affordable access to services. The results highlighted the importance of monitoring caregivers who manifest the identified predictors to attenuate caregiver depression at the population level under the LTCI.

Optimization of X-ray microplanar beam radiation therapy for deep-seated tumors by a simulation study.

A Monte Carlo simulation was applied to study the energy dependence on the transverse dose distribution of microplanar beam radiation therapy (MRT) for deep-seated tumors. The distribution was found to be the peak (in-beam) dose and the decay from the edge of the beam down to the valley. The area below the same valley dose level (valley region) was decreased with the increase in the energy of X-rays at the same beam separation. To optimize the MRT, we made the following two assumptions: the therapeutic gain may be attributed to the efficient recovery of normal tissue caused by the beam separation; and a key factor for the efficient recovery of normal tissue depends on the area size of the valley region. Based on these assumptions and the results of the simulated dose distribution, we concluded that the optimum X-ray energy was in the range of 100-300 keV depending on the effective peak dose to the target tumors and/or tolerable surface dose. In addition, we proposed parameters to be studied for the optimization of MRT to deep-seated tumors.

Psychological stress in a Japanese population with systemic lupus erythematosus: finding from KYSS study.

OBJECTIVES: Daily psychological stress has been proposed as a risk factor for systemic lupus erythematosus (SLE) in Western countries. However, there is little information about the relationship between daily psychological stress and the risk of SLE in a Japanese population. We examined the association between SLE and daily psychological stress. METHODS: A case-control study was conducted to examine the relationship between daily psychological stress and SLE in Japanese females. The participants were 160 female SLE patients and 660 female volunteers. Unconditional logistic regression was used to compute OR and 95% confidence interval (CI), with adjustment for several covariates. RESULTS: Smoking (OR = 2.59; 95% CI, 1.74-3.86), walking (OR = 1.75; 95% CI, 1.81-2.56) and daily psychological stress (OR = 1.88; 95% CI, 1.14-3.10) were increased in patients with SLE after adjusting for age, region and all factors. Smokers with daily psychological stress (OR = 4.70; 95% CI = 2.53-8.77) were more prevalent than nonsmokers without daily psychological stress in SLE. The multiplicative interaction measures between smoking status and daily psychological stress did not reach statistical significance. CONCLUSIONS: The present study suggests the possibility that daily psychological stress as well as smoking might be associated with an increased risk of SLE.

Lifestyle and other related factors for the development of mixed connective tissue disease among Japanese females in comparison with systemic lupus erythematosus.

OBJECTIVE: The etiology of mixed connective tissue disease (MCTD) has not been elucidated in detail. Case control studies of MCTD and systemic lupus erythematosus (SLE) were conducted in order to compare factors related to these two diseases. METHODS: We selected 48 MCTD and 54 SLE female patients throughout Japan from 2009 to 2010. Controls were 182 female patients who visited the clinics of general internal medicine during the study periods. RESULTS: Smoking and walking a longer time showed an increased age-adjusted risk for MCTD as well as SLE. On the other hand, frequent intake of bread increased the risk of MCTD and high intake of green tea decreased the risk of MCTD. Even after an additional adjustment of smoking and drinking, frequent intake of bread increased the risk of MCTD, while walking increased the risk of SLE. CONCLUSION: The present study suggests that Westernization of dietary habits (i.e. frequent intake of bread and low intake of green tea) may increase the risk of MCTD, while walking may increase the risk of SLE (probably due to exposure to the sunlight) among Japanese females. Further studies are needed to confirm the result of the present study.

Tumor necrosis factor receptor-associated periodic syndrome (TRAPS) in Japan: a review of the literature.

Tumor necrosis factor receptor-associated periodic syndrome (TRAPS) is a dominantly inherited autoinflammatory syndrome that is characterized by recurrent episodes of fever attacks associated with rashes, abdominal pain, myalgia, conjunctivitis, chest pain, and arthralgia. Some patients have severe abdominal pain leading to abdominal surgery. Most reported cases of TRAPS involve patients of European ancestry, but there have been nine reports of patients with TRAPS in Japan. Here, we review these nine case reports. Reported TNFRSF1A gene mutations in these nine index patients were C70S, T61I, C70G, C30Y, C30R, N101K, and N25D. Fever (100 %) was seen in all 23 cases. Most patients developed rash (erythema) (84.6 %) and arthralgia (73.3 %), and half suffered from myalgia (54.5 %) and abdominal pain (50.0 %). Although one-half of the patients suffered from abdominal pain, none underwent surgery. In contrast, only a small percentage of patients suffered from chest pain (20.0 %), conjunctivitis (20.0 %), and headache (10.0 %). Almost all cases (95.7 %) concerned patients whose relatives suffered from periodic fever. These findings suggest that the clinical features of Japanese TRAPS patients may be milder than those of patients in Western countries.

Study on X-ray enhancement in Laser-Compton scattering for auger therapy.

PURPOSE: Monochromatic hard X-rays with high brightness are desired for medical applications including Auger therapy. One can generate such X-rays through laser-Compton scattering (LCS) by allowing photons from a compact laser system to interact with electrons accelerated by a compact electron accelerator. In this paper, after a brief description of laser-Compton X-ray sources, a scheme called crab crossing to enhance the X-ray intensity is proposed. The effect of crab crossing is evaluated, and we report our dedicated laser system for the crab crossing LCS research. MATERIALS AND METHODS: The luminosity enhancement factor by crab crossing is evaluated. For the electron beam, a rf deflector will be used to generate a tilted electron beam. For the laser system, chirped pulsed amplification is adopted. Yb-doped optical fibers and a Yb:YAG thin-disk is used for the laser gain media. RESULTS: The luminosity enhancement factor by crab crossing is expected to be 3.8 when the crossing angle is 45 degrees. 10mJ pulse energy was achieved by thin-disk regenerative amplifier. The pulse duration after the pulse compressor was about 1.5 ps. CONCLUSION: We are going to demonstrate the LCS X-ray enhancement by crab crossing of electron beam and laser pulse. The expected enhancement factor is 3.8. We have successfully finished the laser development and the proof-of-principle experiment will be conducted soon.

Fabrication of nanobeads from nanocups by controlling scission/crosslinking in organic polymer materials.

The development of several kinds of micro/nanofabrication techniques has resulted in many innovations in the micro/nanodevices that support today's science and technology. With feature miniaturization, the fabrication tools have shifted from light to ionizing radiation. Here, we propose a simple micro/nanofabrication technique for organic materials using a scanning beam (SB) of ionizing radiation. By controlling the scission/crosslinking of the material via three-dimensional energy-deposition distribution of the SB, appropriate solvents can easily peel off only the crosslinked region from the bulk material. The technique was demonstrated using a focused ion beam and a chlorinated organic polymer. The polymer underwent main-chain scission upon irradiation, but it crosslinked after high-dose irradiation. Appropriate solvents could easily peel off only the crosslinked region from the bulk material. The technique, 'nanobead from nanocup', enabled the production of desired structures such as nanowires and nanomembranes. It can be also applied to the micro/nanofabrication of functional materials.

Factors influencing caregivers' burden among family caregivers and institutionalization of in-home elderly people cared for by family caregivers.

OBJECTIVES: The purpose of this study was to determine the factors related to changes in the burden of caregivers who look after the elderly at home, as well as factors related to the institutionalization of the elderly who require care. The types of care services associated with reducing caregivers' burden and continuing in-home care were also studied. METHODS: The study subjects were adults aged ≥65 years who used the services of in-home care management centres located in Osaka Prefecture, Japan, and their caregivers. This 2-year longitudinal study began in October 2007, with a total of three surveys undertaken once a year. The survey methods included self-administered questionnaires and the review of clinical records. RESULTS: Dementia and its accompanying behavioural disturbances were found to be significantly related to the increased burden of caregivers and the institutionalization of those requiring care. A significantly higher proportion of caregivers with an increasing burden or those who maintained a high level of burden used day care services compared to those in the other groups. CONCLUSION: Preventive intervention against dementia and its accompanying behavioural disturbances should be considered in the day care service to reduce caregivers' burden and to decrease institutionalization.

Trapped radical behavior of electron beam irradiated polytetrafluoroethylene fine powder at various temperatures.

Polytetrafluoroethylene (PTFE) fine powder with 93% crystallinity was irradiated by an electron beam (EB) at various temperatures under a nitrogen atmosphere. Trapped free radicals in PTFE were studied using electron spin resonance (ESR) spectroscopy. The observed spectra of the samples exposed to air after irradiation at various temperatures showed asymmetrical signals, which are middle-chain type peroxide macroradicals derived from fluoroalkyl radicals. The radical yields at each irradiation temperature increased with increasing absorbed dose, and eventually saturated. The higher irradiation temperature resulted in higher radical yields when compared at the same exposed dose. Furthermore, the G-value of the radicals (G(R·)) increases with increasing irradiation temperatures corresponding to each relaxation and transition temperature. It is concluded that the chain reaction by the fluorine extraction from the main chain due to the end-chain radical generated via ß-scission after dissociative electron attachment (DEA) is enhanced by the synergistic effect of heat and radiation.

Association between coffee and green tea intake and pneumonia among the Japanese elderly: a case-control study.

A large prospective cohort study in the United States examined the association between coffee intake and overall and cause-specific mortality and showed a inverse association between pneumonia and influenza deaths and coffee intake. In Japan, the mortality rate of pneumonia in elderly people is high, and its prevention is an important issue. The present study investigated the association between coffee and green tea intake and pneumonia among the elderly. The design was a hospital-based case control study. The cases were patients over 65 years old newly diagnosed as pneumonia. As a control, patients with the same sex and age (range of 5 years) who visited the same medical institution around the same time (within 2 months after examination of the case) for a disease other than pneumonia were selected. There were two controls per case. Odds ratio (OR) and 95% confidence interval (CI) for pneumonia of coffee and green tea intake during the past month were calculated using a conditional logistic regression model. A total of 199 cases and 374 controls were enrolled. When compared to those who do not drink coffee, the OR for pneumonia of those who drink less than one cup of coffee per day was 0.69 (95% CI 0.39-1.21), OR of those who drink one cup was 0.67 (0.38-1.18), and OR of those who drink two or more cups was 0.50 (0.28-0.88) (Trend p = 0.024). No association was found between pneumonia and green tea consumption. This study suggested a preventive association between coffee intake over 2 cups per day and pneumonia in the elderly.

Association between Passive Smoking from the Mother and Pediatric Crohn's Disease: A Japanese Multicenter Study.

Smoking is a risk factor for adult-onset Crohn's disease (CD). Although passive smoking from family members is a major concern, especially in pediatric CD, the number of existing epidemiological studies is limited. This multicenter case-control study aimed to assess the effects of familial smoking on pediatric CD. We examined 22 pediatric CD cases and 135 controls. The subjects' mothers were given a self-administered questionnaire about family smoking before disease onset in the CD group or the corresponding period in the control group. Univariable logistic regression model was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs), whereas dose-response relationship analyses were performed for more in-depth evaluations. Univariable analyses indicated that passive smoking from the mother (OR, 2.09; 95% CI, 0.61-7.10) was not a significant, but a candidate risk factor for developing pediatric CD. In contrast, the dose-response relationship analyses revealed that passive smoking from the mother (OR, 1.17; 95% CI, 1.04-1.31) was significantly associated with pediatric CD. Therefore, passive smoking from the mother may be predominantly associated with the development of pediatric CD. Further follow-up studies comprising environmental measurements of passive smoking exposure doses and genetic factors interaction analysis are necessary.