Dismantling of Reinforced Concrete Using Steam Pressure Cracking System: Drilling and Crack Propagation.

This study investigated a new dismantling system for concrete structures using a steam pressure cracking agent. We improved the mechanical systems such that it can drill through reinforcing steel bars. Therefore, the control method of the system and shape of the drill tip were improved. When the drill tip is stuck with chips and stopped, it is automatically pulled out and reinserted to recover the rotation. By changing the tip angle of the drill bit from 75° to 90°, it became possible to cut reinforcing bars, which were difficult to cut previously. In addition, we designed a crawler-type mechanical system and improved it such that it can be moved to the appropriate position and operated at any angle. This study revealed that the energy required for the drilling process accounts for more than 90% of the total dismantling energy. Through experiments using an impact hammer drill and observations of fracture surfaces using a three-dimensional scanner, we analysed the characteristics of reinforced concrete. In addition, the feasibility of the design for dismantling reinforced concrete was confirmed based on the determined energy associated with crack propagation.

Cutting of Diamond Substrate Using Fixed Diamond Grain Saw Wire.

This study demonstrates that a single-crystal diamond substrate can be cut along designed lines using the diamond-saw-wire cutting method. We developed an original saw-wire fixed diamond-grain using a bronze solder with a high melting temperature. We created a unique product machine system with a high vacuum furnace and a bronze solder that contains a metallic compound. The diamond cutting mechanism employed in this study is based on the mild wear phenomenon, owing to the friction between the diamond surfaces. A linear relationship between the cutting length and wire feed distance was observed. The relationship can be approximated as y = 0.3622x, where y (µm) is the cutting depth and x (km) is the wire feed distance. The life of the saw-wire was longer than that of the 6000 km wire feed distance and was tested by reciprocating an 8-m short wire at a speed, tension, and cutting force of 150 m/min, 1 N, and 0.2 N, respectively. A single crystal diamond substrate could be cut along the designed line, which was more than 2 mm long. The cutting speed was maintained constant at 0.36 µm/km.

rTMS Therapy Reduces Hypofrontality in Patients With Depression as Measured by fNIRS.

Multichannel functional near-infrared spectroscopy (fNIRS) is a tool used to capture changes in cerebral blood flow. A consistent result for depression is a decrease in blood flow in the frontal cortex leading to hypofrontality, which indicates multidomain functional impairment. Repetitive transcranial magnetic stimulation (rTMS) and elective convulsive therapy (ECT) are alternatives to antidepressant drugs for the treatment of depression but the underlying mechanism is yet to be elucidated. The aim of the current study was to evaluate cerebral blood flow using fNIRS following rTMS treatment in patients with depression. The cerebral blood flow of 15 patients with moderate depression after rTMS treatment was measured using fNIRS. While there was clear hypofrontality during pre-treatment (5 ± 2.5), a notable increase in oxygenated hemoglobin was observed after 30 sessions with rTMS (50 ± 15). This increased blood flow was observed in a wide range of channels in the frontal cortex; however, the centroid values were similar between the treatments. Increased blood flow leads to the activation of neuronal synapses, as noted with other neuromodulation treatments such as electroconvulsive therapy. This study describes the rTMS-induced modulation of blood oxygenation response over the prefrontal cortex in patients with depression, as captured by fNIRS. Future longitudinal studies are needed to assess cerebral blood flow dynamics during rTMS treatment for depression.

fNIRS Assessment during an Emotional Stroop Task among Patients with Depression: Replication and Extension.

OBJECTIVE: Accumulated evidence collected via functional near-infrared spectroscopy (fNIRS) has been reported with regard to mental disorders. A previous finding revealed that emotional words evoke left frontal cortex activity in patients with depression. The primary aim of the current study was to replicate this finding using an independent dataset and evaluate the brain region associated with the severity of depression using an emotional Stroop task. METHODS: Oxygenized and deoxygenized hemoglobin recording in the brain by fNIRS on 14 MDD patients and 20 normal controls. RESULTS: Hyperactivated oxygenized hemoglobin was observed in the left frontal cortex on exposure to unfavorable stimuli, but no significant difference was found among patients with depression compared with healthy controls on exposure to favorable stimuli. This result is consistent with previous findings. Moreover, an evoked wave associated with the left upper frontal cortex on favorable stimuli was inversely correlated with the severity of depression. CONCLUSION: Our current work using fNIRS provides a potential clue regarding the location of depression symptom severity in the left upper frontal cortex. Future studies should verify our findings and expand them into a precise etiology of depression.

Correlation between frontal lobe oxy-hemoglobin and severity of depression assessed using near-infrared spectroscopy.

INTRODUCTION: The search for objective biomarkers of psychiatric disorders has a long history. Despite this, no universally accepted instruments or methods to detect biomarkers have been developed. One potential exception is near-infrared spectroscopy, although interpreting the measures of blood flow recorded with this technique remains controversial. In this study, we aimed to investigate the relationship between recorded blood flow and depression severity assessed using the Hamilton depression scale in patients with various psychiatric disorders. METHODS: Enrolled patients (n=43) had DSM-IV diagnoses of major depressive disorder (n=25), bipolar disorder I (n=5), schizophrenia (n=3), dysthymic disorder (n=3), psychotic disorder (n=3), panic disorder (n=2), and Obsessive Compulsive Disorder (n=2). The verbal fluency task was administered during blood flow recording from the frontal and temporal lobes. RESULTS: We found that severity of depression was negatively correlated with the integral value of blood flow in the frontal lobe, irrespective of psychiatric diagnosis (F=5.94, p=0.02). DISCUSSION: Our results support blood flow in the frontal lobe as a potential biomarker of depression severity across various psychiatric disorders. LIMITATION: Limited sample size, no replication in the second set.

Dynamic state of water molecular displacement of the brain during the cardiac cycle in idiopathic normal pressure hydrocephalus.

The predictive accuracy of iNPH diagnoses could be increased using a combination of supplemental tests for iNPH. To evaluate the dynamic state of water displacement during the cardiac cycle in idiopathic normal pressure hydrocephalus (iNPH), we determined the change in water displacement using q-space analysis of diffusion magnetic resonance image. ECG-triggered single-shot diffusion echo planar imaging was used. Water displacement was obtained from the displacement probability profile calculated by Fourier transform of the signal decay fitted as a function of the reciprocal spatial vector q. Then maximum minus minimum displacement (delta-displacement), of all cardiac phase images was calculated. We assessed the delta-displacement in white matter in patients with iNPH and atrophic ventricular dilation (atrophic VD), and in healthy volunteers (control group). Delta-displacement in iNPH was significantly higher than those in the atrophic VD and control. This shows that water molecules of the white matter in iNPH are easily fluctuated by volume loading of the cranium during the cardiac cycle, due to the decrease in intracranial compliance. There was no significant correlation between delta-displacement and displacement. The delta-displacement and the displacement do not necessarily yield the same kind of information. Delta-displacement demonstrated to obtain biophysical information about fluctuation. This analysis may be helpful in the understanding physiology and pathological condition in iNPH and the assisting in the diagnosis.

Evaluation of perfusion-related and true diffusion in vertebral bone marrow: a preliminary study.

Our aim in this study was to obtain noninvasively more detailed information on perfusion and diffusion in vertebral bone marrow. We analyzed two diffusion components using a biexponential function. Eleven healthy volunteers were examined. By a 1.5-T MRI, we performed single-shot diffusion magnetic resonance imaging to acquire diffusion-weighted images (DWIs) with multiple b values. We determined perfusion-related diffusion and true diffusion coefficients (D* and D), the fraction of the perfusion-related diffusion component (F), and the apparent diffusion coefficient (ADC) in the lumbar vertebral body. Then, we compared these diffusion parameters with the bone mineral density (BMD) obtained with dual-energy X-ray absorptiometry. Moreover, the fat fraction (FF) of the bone marrow was calculated by use of double gradient-echo images with and without spectral adiabatic inversion recovery in the same subject. The BMD showed a significant positive correlation with D*, whereas there was no significant correlation between the other diffusion parameters and BMD. There was a negative correlation between the D or ADC and FF, although no correlation was found between D* or F and FF. Diffusion analysis with a biexponential function made it possible to obtain detailed information on bone perfusion and diffusion in healthy young volunteers.

A method for assessing metabolic information on liver and bone marrow by use of double gradient-echo with spectral fat suppression.

Our aim in this study was to create a noninvasive and practical method for evaluating metabolic information on the liver (iron content and lipid infiltration) and spine (bone mineral density and marrow fat degeneration) using double gradient-echo with and without the spectral fat suppression technique (double-GRE-FS). We arranged phantoms made of various concentrations of superparamagnetic iron oxide solution adjacent to neutral fat to obtain slice planes with various fat fractions using the partial volume effect. We obtained double-GRE-FS images and calculated the T2* values. The fat fraction was calculated from signal intensities of double-GRE-FS images after T2* decay, baseline, and slope corrections. We assessed the fat fraction and the relationship between R2* of the water component and the iron concentration. In addition, we evaluated those values in human bone marrow and liver, including a patient with liver steatosis. The actual fat fraction value was consistent with the fat fraction obtained with the double-GRE-FS method, and the calculated fat fraction was unaffected by the iron concentration. There was a strong positive correlation between R2* of the water component and the iron concentration. There was a negative correlation between the fat fraction and the bone mineral density, and the R2* was correlated with the bone mineral density. The calculated fat fraction in the liver steatosis patient was significantly higher than that in healthy volunteers. The double-GRE-FS makes it possible to assess the fat fraction and R2* simultaneously, and to obtain metabolic information on the liver and bone marrow.

Selection of autophagy or apoptosis in cells exposed to ER-stress depends on ATF4 expression pattern with or without CHOP expression.

Cells exposed to ER-stress undergo the Unfolded Protein Response (UPR) to avoid apoptosis, but may also activate autophagy. However, the signal for selection of one of these two protective responses is unknown. To clarify the key switch between autophagy and apoptosis, we examined the correlation of UPR-related signals with autophagy and/or apoptosis inductions in HepG2 cells exposed to three ER-stress inducers (NaF, tunicamycin, and thapsigargin) with time, including the effect of small interfering RNA on the cell responses. Thapsigargin-induced ER-stress caused only apoptosis after ∼2 hr with Ire1 phosphorylation, and Grp78, ATF4, and CHOP expressions. On the other hand, NaF- and tunicamycin-induced ER-stress caused only autophagy in the early stage by ∼8 hr with ATF4 expression and without CHOP expression. ATF4-siRNA completely inhibited the autophagy induced by NaF or tunicamycin with suppressed ATF4 protein and mRNA expressions, and also inhibited apoptosis by thapsigargin with suppression of both ATF4 and CHOP. CHOP-siRNA had no effect on autophagy activation by NaF and tunicamycin. On the other hand, CHOP-siRNA activated autophagy in thapsigargin-induced ER-stress with significant ATF4 expression, and suppressed apoptosis with CHOP suppression. These results showed that ATF4 is the key signal for autophagy induced by ER-stress, and that autophagy is switched to apoptosis by subsequent CHOP upregulation, suggesting that the changeover switch between autophagy and apoptosis is located between ATF4 to CHOP in the PERK pathway.

Prediction of back-scatter radiations to a beam monitor chamber of medical linear accelerators by use of the digitized target-current-pulse analysis method.

In small-field irradiation, the back-scattered radiation (BSR) affects the counts measured with a beam monitor chamber (BMC). In general, the effect of the BSR depends on the opened-jaw size. The effect is significantly large in small-field irradiation. Our purpose in this study was to predict the effect of BSR on LINAC output accurately with an improved target-current-pulse (TCP) technique. The pulse signals were measured with a system consisting of a personal computer and a digitizer. The pulse signals were analyzed with in-house software. The measured parameters were the number of pulses, the change in the waveform and the integrated signal values of the TCPs. The TCPs were measured for various field sizes with four linear accelerators. For comparison, Yu's method in which a universal counter was used was re-examined. The results showed that the variance of the measurements by the new method was reduced to approximately 1/10 of the variance by the previous method. There was no significant variation in the number of pulses due to a change in the field size in the Varian Clinac series. However, a change in the integrated signal value was observed. This tendency was different from the result of other investigations in the past. Our prediction method is able to define the cutoff voltage for the TCP acquired by digitizer. This functionality provides the capability of clearly classifying TCPs into signals and noise. In conclusion, our TCP analysis method can predict the effect of BSR on the BMC even for small-field irradiations.

Brownian motion-magnetophoresis of nano/micro-particles.

A new magnetophoresis method to determine the magnetic susceptibility of single nano/microparticles was developed by applying Brownian motion analysis to determine the size of the particle. This method could measure simultaneously both the magnetophoretic velocity and the radius of the identical single nano/microparticles, which are necessary for the determination of the magnetic susceptibility of the particle. The advantage of this method was demonstrated by the measurement of the diamagnetic susceptibilities of polystyrene particles 500 nm-3 µm in diameter in a paramagnetic 0.5 M manganese(II) chloride solution under a high magnetic field gradient of 5180 T(2) m(-1) generated by a small magnetic circuit.

Two-dimensional flow magnetophoresis of microparticles.

A new two-dimensional micro-flow magnetophoresis device was constructed in a superconducting magnet (10 T) using triangular shaped pole pieces, which could apply a magnetic strength, B(dB/dx), in the range of ca. 0-14,000 T(2) m(-1) across a capillary cell. Polystyrene particles with diameters of 1, 3, and 6 µm were used as test samples in a paramagnetic medium of 1 M MnCl(2) to evaluate the performance of this method. Microparticles migrated across the capillary along the edge of the pole pieces, and then flowed through the gap in the pole piece at a position defined as the migration distance, depending on the magnetic susceptibility and the size of particles as well as the flow rate. The most effective flow rate to exhibit the largest resolution among the particles was theoretically predicted and experimentally confirmed. By this method, the magnetic susceptibilities of individual deoxygenated and non-deoxygenated red blood cells were measured from the relative migration distance.

[Appropriate cardiac phase for measurement of ADC of the brain using ECG-triggered diffusion MRI].

Apparent diffusion coefficients (ADCs) are sometimes overestimated when they are measured in the brain near the basal ganglia because water molecules in brain tissues fluctuate with blood volume loading in the cranium. We determined detailed ADC changes during the cardiac cycle to evaluate the appropriate cardiac phases for accurate measurement of ADC values. Using 1.5 T MRI, we performed ECG-triggered single-shot EPI to obtain ADC maps in each cardiac phase using techniques minimizing the bulk motion effect. The coefficient of variation (CV) of the ADC values during the cardiac cycle was over 50% near the basal ganglia. Moreover, the cardiac phase of the peak ADC value during the cardiac cycle was from 10 to 40% cardiac phases that follow systole. However, the CV of the ADC values of whole cardiac phases was higher than those with phases over 50% of the cardiac cycle near the basal ganglia because the effect of water fluctuation was almost eliminated. Therefore, accurate measurement of ADC values should be obtained from ADC maps of phases over 50% of the cardiac cycle.

Nano-gap magnetophoresis with Raman spectroscopic detection.

As a tool to determine the magnetic susceptibility of a nano/microparticle in a liquid, a nano-gap magnetophoresis device was fabricated using tilted flat glass plates and a permanent magnet. The nano-gap device was not only used to determine the size of particles, but also directly provided measurements of Raman spectra of fractionally trapped particles in the nano-gap device. The performance of the new hyphenated method was demonstrated by an analysis of suspended particle matter in traffic air.

[Analysis of radioactivation induced by high-energy X-rays in medical linear accelerators -estimation of short-lived radioactivated nuclides-].

In medical linear accelerators, radioactivation is induced on the target and neighborhood parts by photoneutrons accompanying a photo-nuclear reaction and leading to higher acceleration energy. We measured the residual radiation from the radioactivated materials according to the time, and tried to identify radioactivated nuclides and their relative quantities by means of measurement results. It was presumed that the main source of residual radiations was the Target, Flattening filter and Primary collimator in the linac head. Among those materials (copper, tungsten), we calculated decrement curves of residual radiations from radioactivated nuclides generated with photo-nuclear reaction or thermal neutron capture reaction by various ratios, and we investigated the ratio that best fit the measured data. Consequently, it was presumed that (66)Cu generated with thermal neutron capture reaction contributed the most to residual radiation, followed by (62)Cu generated with photo-nuclear reaction contributed. It is important to understand various characteristics of these nuclides and to undertake management of the device.

[Analysis of photonuclear activation effect of high-energy medical linear accelerators--measurement of spatial dose distribution and temporal decay curve, and assessment of personnel dosimetry].

The characteristics of activation after high-energy X-rays have been generated by medical linear accelerators were measured using an ionization chamber. Radiation doses increased with rising X-ray energy, based on 10 MV, 15 MV, and 18 MVX-ray measurements. When the total irradiation dose was changed, radiation dose increased with total irradiation dose. When the collimator opened, the radiation dose at a position 15 cm from the isocenter reached about the maximum, which was 2.2 times the dose at the isocenter. The radiation dose became about 0.3 times its level at a position 40 cm from the isocenter, in the outer irradiation field. The dose distribution in the treatment room became almost the same dose extending from the isocenter to 200 cm. Radiation dose decreased gradually while moving away from the target on the treatment beam axis. But it increased again as it approached the floor face. The occupational exposure dose, which was presumed from measurements of the radiation dose 50 cm from the isocenter, was about 0.9 mSv during a year, assuming 600 MU for 1 person, 8 people a day, and 245 days a year. Radiation dose changed with X-ray energy in the machine used, and it was a geometrical constituent in the treatment room. It is important to understand the characteristics of radiation generated by medical linear accelerators.

[Influence of angle-measurement error on pre-sampled MTF and proposal of an optimal technique of angle measurement].

The presampled modulation transfer function (MTF) is recognized as the established metric for characterizing the resolution performance of a digital imaging system. In the past, the three general approaches for assessing the presampled MTF were using the angulated slit, angulated edge, and angulated square-wave test pattern all of which are tilted slightly against the column direction of the detector. In all methods, it is important to determine the exact angle of the respective test devices. In this study, we examined the influence of angle-measurement error in three test devices and the optimal technique of angle measurement. These results demonstrated that the influences of angle-measurement error in each method were equal. We also investigated three angle-measurement techniques using trace of objects, Hough transfer, and comparative observation of synthetic profiles. These results suggested that the technique using synthetic profiles was the most optimal technique in the angle measurement. Through use of the technique, angle-measurement error was completely overcome. This technique will contribute to improved accuracy of presampled MTF measurements.

Significance of asymmetric basal posterior wall thinning in patients with cardiac Fabry's disease.

Although classic Fabry's disease results in multiple causes of death, the cardiac variant of Fabry's disease affects only the cardiac system and results in initial symmetric left ventricular (LV) hypertrophy and later LV dysfunction, asymmetric basal posterior LV wall thinning, restrictive mitral flow, and functional mitral regurgitation with end-stage chronic heart failure (CHF), leading to death. The purpose of this study was to investigate whether these findings predict prognoses in patients with cardiac Fabry's disease. In 13 consecutive men with cardiac Fabry's disease, LV wall thickness, the ejection fraction, mitral E-wave deceleration time, the LV Tei index, and functional mitral regurgitation were measured by echocardiography. Patients were followed for 5 to 96 months (mean 41 +/- 9). Eight patients developed New York Heart Association class III CHF, and 6 experienced cardiac death. A LV Tei index >0.60 and basal posterior LV wall thinning with a ratio of ventricular septal to posterior wall thickness >1.3 significantly preceded CHF and death (Tei index: 4.4 and 5.1 years; posterior wall thinning: 4.0 and 4.7 years), respectively (p <0.05). In conclusion, an increased LV Tei index and asymmetric basal posterior LV wall thinning are important echocardiographic findings that precede CHF and cardiac death in patients with cardiac Fabry's disease.