Fringe counting method for synthetic phase with frequency-modulated laser diodes.

Fringe counting method with laser diodes (LDs) for displacement measurement has been constructed. Two LDs are frequency modulated by mutually inverted sawtooth currents on an unbalanced two-beam interferometer. The mutually inverted sawtooth-current modulation of LDs produces interference fringe signals with opposite signs for respective wavelengths. The two fringe signals are fed to an electronic mixer to produce a synthetic fringe signal with a reduced sensitivity to the synthetic wavelength. Synthetic fringe pulses derived from the synthetic fringe signal make a fringe counting system possible for faster movement of the tested mirror.

Correlation between brain damage, associated biomarkers, and medication in psychiatric inpatients: A cross-sectional study.

BACKGROUND: We clarified the correlation between brain damage, associated biomarkers and medication in psychiatric patients, because patients with schizophrenia have an increased risk of stroke. METHODS: The cross-sectional study was performed from January 2013 to December 2015. Study participants were 96 hospitalized patients (41 men and 55 women) in the Department of Psychiatry at Kohnodai Hospital, National Center for Global Health and Medicine, Ichikawa, Chiba, Japan. Patients were classified into schizophrenia (n=70) and mood disorders (n=26) by psychiatric diagnoses with DSM-IV-TR criteria. RESULTS: The incidence of brain damage [symptomatic and silent brain infarctions (SBIs) and white matter hyperintensity (WMH)] was correlated more with mood disorders than with schizophrenia. It has been previously shown that the concentrations of protein-conjugated acrolein (PC-Acro) and interleukin-6 (IL-6) increased in plasma of brain infarction patients together with C-reactive protein (CRP). The concentration of PC-Acro was significantly higher in patients with mood disorders than in those with schizophrenia. The concentration of IL-6 in both groups was nearly equal to that in the control group, but that of CRP in both groups, especially in mood disorders, was higher than that in the control group. Accordingly, the relative risk value for brain infarction was higher in patients with mood disorders than with schizophrenia. Medication with atypical antipsychotics reduced PC-Acro significantly in all psychiatric patients and reduced IL-6 in mood disorder patients. CONCLUSION: Measurement of 3 biomarkers (CRP, PC-Acro and IL-6) are probably useful for judgement of severity of brain damage and effectiveness of medication in psychiatric patients.

Increased Silent Brain Infarction Accompanied With High Prevalence of Diabetes and Dyslipidemia in Psychiatric Inpatients: A Cross-Sectional Study.

OBJECTIVE: Patients with schizophrenia have increased risk of atherosclerotic diseases. It is already known that lifestyle-related disorders and the use of antipsychotics are closely related with the progression of atherosclerosis in psychiatric patients. Stroke as well as coronary heart disease play an important role in the cause of death in Asia and Japan. Thus, we studied the prevalence of cerebrovascular disease in psychiatric inpatients in Japan using brain magnetic resonance imaging (MRI). METHOD: This cross-sectional study was performed from January 2012 to December 2013. Study participants were 152 hospitalized patients (61 men and 91 women) in the Department of Psychiatry at Kohnodai Hospital, National Center for Global Health and Medicine, Ichikawa City, Japan. Mean ages were 50.0 and 57.1 years old for men and women, respectively. The diagnoses (DSM-IV-TR criteria) of participants were schizophrenia (69.1%), mood disorder (18.4%), and other mental disorders (12.5%). We checked physical status, metabolic status of glucose and lipid levels, and brain MRI within 1 week of admission. RESULTS: The study group showed a significantly high prevalence of diabetes and low high-density lipoprotein (HDL) cholesterolemia in both sexes (n = 61 in men, n = 91 in women, P < .05). In the study group, serum fasting plasma glucose and hemoglobin A1c levels were significantly high (n = 152, P < .05), but serum HDL cholesterol and total cholesterol were significantly low in both sexes (n = 61 in men, n = 90 in women, P < .05), and triglycerides were low in men (n = 61, P < .05). Silent brain infarction was recognized at a higher rate (n = 98, P < .05) compared with healthy controls. CONCLUSIONS: Participants in this study had an increased ratio of silent brain infarction compared with Japanese healthy controls, accompanied with higher ratios of diabetes and low HDL cholesterol.

Large step-height measurements using multiple-wavelength holographic interferometry with tunable laser diodes.

Accurate measurement of large step heights using multiple-wavelength holographic interferometry is realized using laser diodes. Due to the high-resolution wavelength tunability of such lasers, a pair of holograms with a wavelength difference of less than 0.01 nm is recorded and used to extract a phase difference having a large synthetic wavelength. Phase differences with synthetic wavelengths ranging from 2.5 to 73 mm are extracted by using pairs of holograms with wavelength differences between 0.3 and 0.01 nm. By combining the phase differences, measurements with a step height of 18 mm and an rms error of 0.04 mm could be achieved. The requirements for performing the phase unwrapping are discussed. Precise knowledge of the recording wavelengths is required to correctly perform this unwrapping.

Multiple-wavelength digital holographic interferometry using tunable laser diodes.

Here we present multiple-wavelength digital holographic interferometry with a wide measurement range using laser diodes. Small wavelength differences can be easily realized by the wavelength tuning of laser diodes with injection current controls. A contour map of an object with a wide measurement range and a high sensitivity is demonstrated by combining a few contour maps with several measurement sensitivities. Synthetic wavelengths are calibrated using a known height difference. This alleviates the need to have high precise knowledge of the recording wavelengths. The synthetic wavelengths ranged from ~3 mm for high measurement sensitivity to ~4 cm for wide measurement range. An rms error of ~35 mum for a ~1 cm height measurement is shown. The measured profile of holographic interferometry agrees with a standard stylus instrument.

Phase-shift-locked interferometer with a wavelength-modulated laser diode.

A phase-shift-locked interferometer has been constructed for distance measurement. A phase shift produced by sawtooth-current modulation of a laser diode is locked to a phase difference preset by polarization optics that consists of a quarter-wave plate and polarizers through an electrical feedback technique. An optical path difference can be measured from the locked sawtooth-wave current amplitude in real time. The sensitivity of the interferometer is discussed.