61 research outputs found
Non-volatile hybrid optical phase shifter driven by a ferroelectric transistor
Optical phase shifters are essential elements in photonic integrated circuits
(PICs) and function as a direct interface to program the PIC. Non-volatile
phase shifters, which can retain information without a power supply, are highly
desirable for low-power static operations. Here a non-volatile optical phase
shifter is demonstrated by driving a III-V/Si hybrid metal-oxide-semiconductor
(MOS) phase shifter with a ferroelectric field-effect transistor (FeFET)
operating in the source follower mode. Owing to the various polarization states
in the FeFET, multistate non-volatile phase shifts up to 1.25{\pi} are obtained
with CMOS-compatible operation voltages and low switching energy up to 3.3 nJ.
Furthermore, a crossbar array architecture is proposed to simplify the control
of non-volatile phase shifters in large-scale PICs and its feasibility is
verified by confirming the selective write-in operation of a targeted FeFET
with a negligible disturbance to the others. This work paves the way for
realizing large-scale non-volatile programmable PICs for emerging computing
applications such as deep learning and quantum computing
Non-volatile optical phase shift in ferroelectric hafnium zirconium oxide
A non-volatile optical phase shifter is a critical component for enabling
large-scale, energy-efficient programmable photonic integrated circuits (PICs)
on a silicon (Si) photonics platform. While ferroelectric materials like BaTiO3
offer non-volatile optical phase shift capabilities, their compatibility with
complementary metal-oxide-semiconductor (CMOS) fabs is limited. Hence, the
search for a novel CMOS-compatible ferroelectric material for non-volatile
optical phase shifting in Si photonics is of utmost importance. Hafnium
zirconium oxide (HZO) is an emerging ferroelectric material discovered in 2011,
which exhibits CMOS compatibility due to the utilization of high-k dielectric
HfO2 in CMOS transistors. Although extensively studied for ferroelectric
transistors and memories, its application in photonics remains relatively
unexplored. Here, we show the optical phase shift induced by ferroelectric HZO
deposited on a SiN optical waveguide. We observed a negative change in
refractive index at a 1.55 um wavelength in the pristine device regardless of
the direction of an applied electric filed. We achieved approximately pi phase
shift in a 4.5-mm-long device with negligible optical loss. The non-volatile
multi-level optical phase shift was confirmed with a persistence of > 10000 s.
This phase shift can be attributed to the spontaneous polarization within the
HZO film along the external electric field. We anticipate that our results will
stimulate further research on optical nonlinear effects, such as the Pockels
effect, in ferroelectric HZO. This advancement will enable the development of
various devices, including high-speed optical modulators. Consequently,
HZO-based programmable PICs are poised to become indispensable in diverse
applications, ranging from optical fiber communication and artificial
intelligence to quantum computing and sensing
Programs for calculating the statistical powers of detecting susceptibility genes in case–control studies based on multistage designs
Motivation: A two-stage association study is the most commonly used method among multistage designs to efficiently identify disease susceptibility genes. Recently, some SNP studies have utilized more than two stages to detect disease genes. However, there are few available programs for calculating statistical powers and positive predictive values (PPVs) of arbitrary n-stage designs
Referral from secondary care and to aftercare in a tertiary care university hospital in Japan
BACKGROUND: In Japan, all citizens are covered by the national insurance system in which universal free access to healthcare services is promised to everybody. There are no general physicians or gatekeepers in the Japanese healthcare system. METHODS: We studied the pattern of referral of inpatients from secondary care hospitals to a tertiary care university hospital and the reverse referral under the situations using a geographic information system (GIS), taking paediatric inpatients as an example. RESULTS: The results showed that 61.2% of the patients were directly admitted to the hospital without referral from other hospitals or clinics and that 82.8% of the inpatients were referred to the outpatient department of the hospital to which they had been admitted. GIS analysis for the inpatients service area showed the hospital functions as both a secondary care hospital and tertiary care hospital. Patients who lived near the hospital tended to be admitted directly to the hospital, and patients who lived far from the hospital tended to utilize the hospital as a tertiary care provider. There were territorial disputes with other secondary care hospitals. To estimate spatial differences in referral to aftercare, we analyzed the spatial distribution of inpatients with focus on their length of hospital stay (LOS). GIS analysis revealed apparent foci of patients with long LOS and those with low LOS. CONCLUSION: These results suggest that the function of university hospital in Japan is unspecialized and that the referral route from the university hospital to aftercare is also unequipped
Tumor size and proliferative marker geminin levels associated with SUVmax levels on PET for breast cancers
It has been well established that maximum standardized uptake value (SUVmax) for 18F-fluorodeoxyglucose positron-emission tomography/computed tomography (FDG PET/CT) is clinically useful for evaluating treatment efficacy as well as predicting prognosis of breast cancer patients. Although SUVmax reflects increased glucose uptake and metabolism possibly induced by activation of growth factor signaling or TP53 dysfunction, tumor characteristics of SUVmax-high breast cancers remain to be elucidated. For the present study, we used immunohistochemical staining to investigate expressions of phospho-ribosomal protein S6 (pS6, downstream molecule of phosphatidyl inositol 3-kinase/Akt/mammalian target of the rapamycin/S6K pathway) and phosphor-p44/42 mitogen-activated protein kinase (pMAPK). Expression levels of TP53 and proliferative marker geminin as well as Ki67 were also examined by means of immunostaining in 163 invasive breast cancers. Cutoff values were set at 10% for pS6, 20% for pMAPK and TP53, and 4% for geminin. The SUVmax levels were significantly higher in the pS6-positive (p = 0.0173), TP53-positive (p = 0.0207) and geminin-high cancers (p2cm and geminin-high showed SUVmax-high, while only 6 of 49 (12.2%) breast cancers ≤2cm in size and with low geminin levels were SUVmax-high. In conclusion, we could determine that breast cancers with a large tumor and a geminin-high rather than Ki67- high proliferative marker were significantly associated with high levels of SUVmax. These findings may signify that SUVmax reflects tumor characteristics with high proliferative activity but not activation of mTOR/S6K and MAPK pathways or increased glucose metabolism due to dysfunction of TP53
Effect of an education program on improving knowledge of schizophrenia among parents of junior and senior high school students in Japan
<p>Abstract</p> <p>Background</p> <p>Early detection and intervention in schizophrenia are important in improving quality of life after treatment and are major issues in psychiatric care. Therefore, it is necessary to increase knowledge of schizophrenia among the general public. Among parents of junior and senior high school students in Japan, we compared rates of correct answers for items on knowledge of schizophrenia and ability to discriminate this psychosis from other disorders on questionnaires given before and after viewing a web-based education program.</p> <p>Methods</p> <p>Questionnaires were distributed to 2,690 parents. The program was developed to help parents obtain a basic understanding of schizophrenia and to emphasize the necessity of early detection.</p> <p>Results</p> <p>Before the program, the rate of correct answers was 77% for items concerning basic knowledge of schizophrenia, 47% for "discrimination of schizophrenia symptoms," and 30% for "discrimination of prodromal symptoms." The program resulted in an improvement in basic knowledge of schizophrenia, discrimination of schizophrenia symptoms, and discrimination of prodromal symptoms (<it>P </it>< 0.001 for all).</p> <p>Conclusions</p> <p>Our web-based education program was useful in helping parents acquire a basic knowledge of schizophrenia and discriminate correctly the symptoms of schizophrenia.</p
Profit and loss analysis for an intensive care unit (ICU) in Japan: a tool for strategic management
BACKGROUND: Accurate cost estimate and a profit and loss analysis are necessary for health care practice. We performed an actual financial analysis for an intensive care unit (ICU) of a university hospital in Japan, and tried to discuss the health care policy and resource allocation decisions that have an impact on critical intensive care. METHODS: The costs were estimated by a department level activity based costing method, and the profit and loss analysis was based on a break-even point analysis. The data used included the monthly number of patients, the revenue, and the direct and indirect costs of the ICU in 2003. RESULTS: The results of this analysis showed that the total costs of US 2,295,044. However, it was determined that the ICU required at least 1,986 patient days within one fiscal year based on a break-even point analysis. As a result, an annual deficit of US$ 383,008 has occurred in the ICU. CONCLUSION: These methods are useful for determining the profits or losses for the ICU practice, and how to evaluate and to improve it. In this study, the results indicate that most ICUs in Japanese hospitals may not be profitable at the present time. As a result, in order to increase the income to make up for this deficit, an increase of 437 patient days in the ICU in one fiscal year is needed, and the number of patients admitted to the ICU should thus be increased without increasing the number of beds or staff members. Increasing the number of patients referred from cooperating hospitals and clinics therefore appears to be the best strategy for achieving these goals
Impaired psychological recovery in the elderly after the Niigata-Chuetsu Earthquake in Japan:a population-based study
BACKGROUND: An earthquake measuring 6.8 on the Richter scale struck the Niigata-Chuetsu region of Japan at 5.56 P.M. on the 23rd of October, 2004. The earthquake was followed by sustained occurrence of numerous aftershocks, which delayed reconstruction of community lifelines. Even one year after the earthquake, 9,160 people were living in temporary housing. Such a devastating earthquake and life after the earthquake in an unfamiliar environment should cause psychological distress, especially among the elderly. METHODS: Psychological distress was measured using the 12-item General Health Questionnaire (GHQ-12) in 2,083 subjects (69% response rate) who were living in transient housing five months after the earthquake. GHQ-12 was scored using the original method, Likert scoring and corrected method. The subjects were asked to assess their psychological status before the earthquake, their psychological status at the most stressful time after the earthquake and their psychological status at five months after the earthquake. Exploratory and confirmatory factor analysis was used to reveal the factor structure of GHQ12. Multiple regression analysis was performed to analyze the relationship between various background factors and GHQ-12 score and its subscale. RESULTS: GHQ-12 scores were significantly elevated at the most stressful time and they were significantly high even at five months after the earthquake. Factor analysis revealed that a model consisting of two factors (social dysfunction and dysphoria) using corrected GHQ scoring showed a high level of goodness-of-fit. Multiple regression analysis revealed that age of subjects affected GHQ-12 scores. GHQ-12 score as well as its factor 'social dysfunction' scale were increased with increasing age of subjects at five months after the earthquake. CONCLUSION: Impaired psychological recovery was observed even at five months after the Niigata-Chuetsu Earthquake in the elderly. The elderly were more affected by matters relating to coping with daily problems
Factor structure of the General Health Questionnaire (GHQ-12) in subjects who had suffered from the 2004 Niigata-Chuetsu Earthquake in Japan: a community-based study
<p>Abstract</p> <p>Background</p> <p>Factor structure of the 12-item General Health Questionnaire (GHQ-12) was studied by a survey of subjects who had experienced the 2004 Niigata-Chuetsu earthquake (6.8 on the Richter scale) in Japan.</p> <p>Methods</p> <p>Psychological distress was measured at two years after the earthquake by using GHQ-12 in 2,107 subjects (99.0% response rate) who suffered the earthquake. GHQ-12 was scored by binary, chronic and Likert scoring method. Confirmatory factor analysis was used to reveal the factor structure of GHQ-12. Categorical regression analysis was performed to evaluate the relationships between various background factors and GHQ-12 scores.</p> <p>Results</p> <p>Confirmatory factor analysis revealed that the model consisting of the two factors and using chronic method gave the best goodness-of-fit among the various models for factor structure. Recovery in the scale for the factor 'social dysfunction' was remarkably impaired compared with that of the factor 'dysphoria'. Categorical regression analysis revealed that various factors, including advanced age, were associated with psychological distress. Advanced age affected the impaired recovery of factor 'social dysfunction' score as well as total GHQ score.</p> <p>Conclusion</p> <p>The two-factor structure of GHQ-12 was conserved between the survey at five month and that at two years after the earthquake. Impaired recovery in the ability to cope with daily problems in the subjects who had experienced the earthquake was remarkable even at two years after the earthquake.</p
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