Controlling Ionic Conductivity in Organometallic Ionic Liquids through Light-Induced Coordination Polymer Formation and Thermal Reversion.

Owing to their high ionic conductivity and negligible vapor pressure, ionic liquids (ILs) find applications in various electronic devices. However, fabricating IL-based photocontrollable devices remains a challenge. In this study, we developed organometallic ILs with reversible light- and heat-controlled ionic conductivities for potential use in tunable devices. The physical properties and stimulus responses of ILs containing a cationic sandwich Ru complex with two coordinating substituents were investigated. UV photoirradiation of these ILs triggered cation photodissociation, resulting in their transformation into viscoelastic coordination polymers wherein the coordinating substituents bridged the Ru centers. Owing to the anion coordination, salts with coordinating anions such as CF3SO2NCN-, B(CN)4-, and BF2(CN)2- exhibited faster response and higher conversion than those with noncoordinating anions including (FSO2)2N- and (CF3SO2)2N-. All photoproducts reverted to their original ILs upon heating, except for the photoproduct of the BF2(CN)2 salt, which decomposed upon heating. Light- and heat-induced reversible changes occur in most cases between the high-ionic-conductive IL state and low-ionic-conductive coordination polymer state. Unlike previously reported ILs with three or one cation substituent, the current ILs exhibited both high reactivity and large ionic conductivity changes.

Si-based agent alleviated small bowel ischemia-reperfusion injury through antioxidant effects.

The progression of small bowel ischemia-reperfusion (IR) injury causes cells in the intestinal tract to undergo necrosis, necessitating surgical resection, which may result in loss of intestinal function. Therefore, developing therapeutic agents that can prevent IR injury at early stages and suppress its progression is imperative. As IR injury may be closely related to oxidative stress, antioxidants can be effective therapeutic agents. Our silicon (Si)-based agent, an antioxidant, generated a large amount of hydrogen in the intestinal tract for a prolonged period after oral administration. As it has been effective for ulcerative colitis, renal failure, and IR injury during skin flap transplantation, it could be effective for small intestinal IR injury. Herein, we investigated the efficacy of an Si-based agent in a mouse model of small intestinal IR injury. The Si-based agent suppressed the apoptosis of small intestinal epithelial cells by reducing the oxidative stress induced by IR injury. In addition, the thickness of the mucosal layer in the small intestine of the Si-based agent-administered group was significantly higher than that in the untreated group, revealing that Si-based agent is effective against small intestinal IR injuries. In the future, Si-based agents may improve the success rate of small intestine transplantation.

[Usefulness of Electron Density Calculated from Dual Energy CT in Differential Diagnosis between Hepatocellular Carcinoma and Hepatic Hemangioma].

PURPOSE: The aim of this study were to compare electron density (ED), obtained by dual energy computed tomography (DECT), between hepatocellular carcinoma (HCC) and hemangioma, and to assess the differential diagnostic performance of ED between HCC and hemangioma. METHODS: A total of 46 patients (27 men and 19 women; mean age, 65.7±14.0 years) diagnosed with HCC or hemangioma who underwent upper abdominal DECT between October 2021 and December 2022 were included. ED of each lesion was measured. Relative ED (rED), which is normalized by the ED of background liver parenchyma, was calculated. ED and rED of HCC and hemangioma were statistically analyzed. RESULTS: The HCC group showed significantly higher ED (48.1±5.2) and rED (80.0±7.3) than the hemangioma group (43.7±4.1, 69.7±7.2, respectively) (p<0.01). The area under the curve of rED was greater than that of ED, but no significant difference was found (p=0.153). CONCLUSION: ED may help in the differential diagnosis between HCC and hemangioma.

Effect of the new silicon-based agent on the symptoms of interstitial pneumonitis.

Interstitial pneumonia (IP) is a collective term for diseases whose main lesion is fibrosis of the pulmonary interstitium, and the prognosis associated with acute exacerbation of these conditions is often poor. Therapeutic agents are limited to steroids, immunosuppressants, and antifibrotic drugs, which and have many side effects; therefore, the development of new therapeutic agents is required. Because oxidative stress contributes to lung fibrosis in IP, optimal antioxidants may be effective for the treatment of IP. Silicon (Si)-based agents, when administered orally, can continuously generate a large amount of antioxidant hydrogen in the intestinal tract. In this study, we investigated the effect of our Si-based agent on methotrexate-induced IP, using the IP mouse models. Pathological analysis revealed that interstitial hypertrophy was more significantly alleviated in the Si-based agent-treated group than in the untreated group (decreased by about 22%; P < 0.01). Moreover, additional morphological analysis demonstrated that infiltration of immune cells and fibrosis in the lungs were significantly inhibited by treatment with the Si-based agent. Furthermore, Si-based agent reduced oxidative stress associated with IP by increasing blood antioxidant activity. (increased by about 43%; P < 0.001). Taken together, these results suggest that Si-based agents can be effective therapeutic agents for IP.

Assessing the progression of segmental fibrosis in chronic liver disease using extracellular volume fractions.

PURPOSE: To assess the segmental difference of liver fibrosis during the progression of chronic liver disease (CLD) using hepatic extracellular volume fractions (fECVs) obtained by dual-energy CT. METHODS: A total of 218 patients (92 men and 126 women; mean age, 67.8 ± 11.7 years) with CLD and 85 patients (44 men and 41 women; mean age, 62.8 ± 13.7 years) without CLD as a control underwent dual-energy computed tomography (CT) of the liver (5-min equilibrium phase images). The iodine densities of the lateral, medial, anterior, and posterior segments and the aorta were measured, and fECVs were calculated. Comparisons of the fECV of each segment and for each albumin-bilirubin (ALBI) grade were then statistically analyzed. RESULTS: In the control group and ALBI grades 1 and 3, no significant difference in fECV was found between each segment, whereas in ALBI grade 2, the fECVs were significantly larger in the medial and anterior than in the other segments (p < 0.001). The fECVs of the lateral and posterior segments significantly increased with higher ALBI grade (p < 0.001). The fECVs of the medial and anterior segments were significantly increased with higher ALBI grade, up to grade 2 (p < 0.001), but no significant difference was found between ALBI grades 2 and 3. CONCLUSION: During the progression of CLD, fibrosis antecedently progressed in the medial and anterior segments, followed by the other liver segments.

[Evaluation of Long-term Fluctuation of Geometric Distortion in MRI for Radiation Therapy Planning by Using an Automatic Analysis Tool].

High tissue contrast in magnetic resonance imaging (MRI) allows better radiotherapy planning. However, geometric distortion in MRI induces inaccuracies affecting such planning, making it necessary to evaluate the characteristics of such geometric distortion. Although many studies have considered geometric distortion, most of these involved measurements performed only a few times. In this study, we evaluated MRI device-specific geometric distortion over long term and measured its variation by using an automatic analysis tool. The result showed that geometric distortion increased with distance from the center along both lateral and longitudinal directions. Specifically, the average distortion rate and average diameter error over the full measurement period increased by up to 1.02% and 1.96 mm, respectively, when using T1 weighted Image (WI) 3D fast spoiled gradient echo (FSPGR) at R15. In the case of T2 WI 2D fast spin echo (FSE) at R15, the standard deviation of the distortion rate and diameter error increased up to 0.38%, 0.72 mm, respectively. We conclude that periodic quality assurance of geometric distortion should be performed in order to maintain geometric distortion within allowable values.

A three-dimensional cross-directional bilateral filter for edge-preserving noise reduction of low-dose computed tomography images.

BACKGROUND: Image-based noise reduction techniques are useful because they can be applied across various computed tomography (CT) scanner models from different vendors, regardless of the iterative reconstruction availability. The purpose of this study was to propose a 3-dimensional cross-directional bilateral filter (3D-CDBF) and compare the edge-preserving noise reduction on low-dose CT images to a model-based iterative reconstruction (MBIR). METHODS: The 3D-CDBF comprises a bilateral filter and a smoothing filter applied in range filtering. The filtering process was applied with four iterations using empirically determined parameters that yielded the best tradeoff between noise reduction and edge preservation for a very low radiation dose of 2.5 mGy. In-plane and z-directional edge preservation performances for low-contrast rod phantoms (60 Hounsfield units) were compared to a clinically available MBIR and a conventional 3D bilateral filter (3D-BF), using task-based spatial resolution (task-based transfer function: TTF) and slice thickness. Moreover, the noise power spectra (NPS) were compared. Furthermore, performance was compared on abdominal CT images acquired from volunteers at 2.5 mGy (approved by our institutional review board). RESULTS: In phantom tests, 3D-CDBF provided 28.5% higher spatial resolution at 50%TTF compared to MBIR. Moreover, total NPS was lower, while the slice thickness (z-axis resolution) was slightly broader than that achieved by MBIR (0.99 mm vs. 0.92 mm). 3D-BF was inferior to both 3D-CDBF and MBIR in all measurements. Consistent with phantom results, 3D-CDBF significantly reduced noise on abdominal images compared to MBIR (P < 0.001), exhibiting better preservation of organ edges. CONCLUSION: This 3D-CDBF may provide superior edge preserving noise reduction of low-dose CT images compared to currently available MBIR.

A Universal Design Method for Reflecting Physical Characteristics Variability: Case Study of a Bicycle Frame.

To achieve a Universal Design, designers must consider diverse users' physical and functional requirements for their products. However, satisfying these requirements and obtaining the information which is necessary for designing a universal product is very difficult. Therefore, we propose a new design method based on the concept of set-based design to solve these issues. This paper discusses the suitability of proposed design method by applying bicycle frame design problem.

[Development of simple processing for deleting undershooting artifact using the FBP method ─evaluation of simulation data─].

The undershooting artifact occurs using the filtered back projection (FBP) method. This artifact is influenced by a ramp filter. Thereby, the fall of the target accumulation and a deficit arise and it becomes a clinical problem. We developed a new image reconstruction method based on the FBP method to delete the undershooting artifact of FBP. The image quality of the FBP method is equivalent to that obtained by an evaluation using a digital phantom. The two segmentation and ordinary FBP methods were evaluated in terms of hot contrast, cold contrast, coefficient of variation (%CV), and root mean square uncertainty (%RSMU). The two segmentation FBP method showed equivalent values of hot contrast, % CV, and% RSMU compared with those of the ordinary FBP method. With a threshold level value, cold contrast sharply changed. However, when the threshold level of the two segmentation FBP method was set as the proper value, 90% contrast was obtained. It is necessary to set a threshold level as a proper value using the two segmentation FBP methods. I thought that it can delete an artifact in a simple way, without impairing the image quality. However, it is an examination of only a digital phantom this time. Before using it clinically, one has to use and verify a real phantom.

Heat-induced formation of myosin oligomer-soluble filament complex in high-salt solution.

Heat-induced aggregation of myosin into an elastic gel plays an important role in the water-holding capacity and texture of meat products. Here, we investigated thermal aggregation of porcine myosin in high-salt solution over a wide temperature range by dynamic light scattering experiments. The myosin samples were readily dissolved in 1.0 M NaCl at 25 °C followed by dilution into various salt concentrations. The diluted solutions consistently contained both myosin monomers and soluble filaments. The filament size decreased with increasing salt concentration and temperature. High temperatures above Tm led to at least partial dissociation of soluble filaments and thermal unfolding, resulting in the formation of soluble oligomers and binding to the persistently present soluble filaments. Such a complex formation between the oligomers and filaments has never been observed. Our results provide new insight into the heat-induced myosin gelation in high-salt solution.

[Comparison of the absorbed dose at calibration depth of photon beams using the Japan Society of Medical Physics 12 beam quality conversion factor in the presence or absence of a waterproofing sleeve].

In standard external beam radiotherapy dosimetry, which is based on absorbed dose by water, the absorbed dose at any calibration depth is calculated using the same beam quality conversion factor, regardless of the presence or absence of a waterproofing sleeve. In this study, we evaluated whether there were differences between absorbed doses at calibration depths calculated using a beam quality conversion factor including a wall correction factor that corresponds to a waterproofing sleeve thickness of 0.3 mm, and without a waterproofing sleeve. The Japan Society of Medical Physics (JSMP) has reported that the uncertainty of the results using a beam quality conversion factor that included a wall correction factor corresponding to a waterproofing sleeve thickness of 0.3 mm, regardless of the presence or absence of the sleeve, was 0.2%. This uncertainty proved to be in agreement with the reported range.

[A comparison of absorbed doses to water in photon beams in Japan Society of Medical Physics 01 and 12].

A comparison of absorbed doses to water at a calibration depth determined by Japan Society of Medical Physics (JSMP) 12 and 01 was conducted, using a farmer type ionization chamber. The absorbed dose to water calibration factor (ND,W,Q0) and beam quality conversion factor (kQ,Q0) for JSMP 12 were smaller than the absorbed dose to water calibration factor and beam quality conversion factor for JSMP 01. Differences in absorbed doses at a calibration depth were -0.78% for 6 MV photon beam and -0.94% for 10 MV photon beam. In the present experiment, absorbed doses at a calibration depth were measured, using a farmer type ionization chamber. Further experiments at a larger number of facilities should be conducted to reveal the status of measurement of absorbed doses at a calibration depth using JSMP 12.

[Usefulness of top-hat transform processing in whole body bone scintigraphy].

To assess the usefulness of top-hat transform processing in whole body bone scintigraphy, five radiological technicians interpreted both original and top-hat processed images to determine the improvement of lesion detectability and interpretation time. For the evaluation of detectability, receiver operating characteristic (ROC) analysis was performed. The area under the curve (AUC) calculated from the ROC curve was improved in all observers (from 0.786 to 0.864 in average), although no significant difference was observed. However, the interpretation time was improved significantly (from 24.5 to 16.2 s in average). Top-hat transform processing in whole body bone scintigraphy is thought to be useful for the improvement of lesion detectability and interpretation time.

Estimation of aortic-to-radial artery distribution of arterial wall elasticity.

OBJECTS: The purpose of this paper is to clarify the cause of the peaking/steepening phenomenon and pressure gradient after cardiopulmonary bypass by measuring the distribution of intra-arterial pressures and that of pulse wave velocities and estimating the vascular wall elasticity's from the aorta to radial artery. METHODS: We measured the intra-arterial pressures and pulse wave velocities simultaneously from aorta to radial artery using a guide-wire tipped with a pressure transducer before and after cardio-pulmonary bypass (CPB), and calculated the distribution of the stiffness parameters (called ß) of aorta-to-radial artery wall. Thereafter, we converted ß's into the wall elasticity's. RESULTS: We found that before CPB the intra-vascular pressures increased gradually from aorta to radial artery, and that corresponding ß and wall elasticity increased simultaneously. After CPB, the intra-arterial pressure and ß or wall elasticity showed the gradual decrease from aorta to radial artery. These results suggest that aortic-to-radial artery pressure change is attributed to gradual change in ß, that is, in the wall elasticity. CONCLUSIONS: The findings indicate that the gradual rise and fall in ß, namely, the increase and decrease in vascular elasticity may account for the peaking, steepening and pressure gradient.

Estimating input original waveform from catheter-manometer system output waveform--an experimental study with pulmonary artery catheter.

The present study was performed to investigate the precision of and problems in arithmetic operations for synthesis/estimation of the input waveform from the output waveform of a pulmonary artery catheter (PAC) manometer system, by imposing arterial pressure waveform as an input pressure waveform. When a PAC manometer system is regarded as a second-order system, the input waveform can be synthesized/estimated from the output waveform by determining the natural frequency (fn), and damping coefficient (ζ) of the said system. The precision of synthesis/estimation diminished with the decreasing fn of the PAC manometer system. An attempt was thus made to explore the cause of the reduction in precision of estimation due to decreases in fn by constructing a second-order system equivalent circuit and a differentiation arithmetic circuit on the circuit simulator. The results demonstrated that correct synthesis/estimation of input waveform were attainable only when the set of fn and ζ for the arithmetic circuit coincided with that of the PAC manometer system. Decreases in fn correspond to such instances where the PAC manometer system can no longer be regarded as a second-order system, thus nullifying the measured fn and ζ. This accounts for the reduction in precision.

Design and its application of the f(n)-zeta chart capable of direct readout of the highest frequency indicating the limit of obtaining distortion-free waveforms.

We have already reported that the highest frequency (f(h)) could serve as an index for evaluating the fidelity of pressure waveform derived via a catheter manometer system and be read off by the f(n)-zeta chart. Fh is determined by the natural frequency (f(n)) and damping coefficient ( zeta ) in the frequency characteristics of the system. Inversely, f(h) determines two pairs of f(n) and zeta in the f(n)-zeta chart, one in the case of zeta < 0.7 and the another zeta > 0.7. Then, each pair of f(n) and zeta determines respectively the resonant frequency (f(r)) and its amplitude (Ar) ( zeta < 0.7), or the corner frequency (f(c)) and its amplitude (Ac) ( zeta > 0.7) in the frequency characteristics. Thus, the point (f(r), Ar) or (f(c), Ac) represents the position of f(h) projected in the frequency characteristics. Repeating the same operation for other f(n) and zeta corresponding to the same f(h), yields the curve of f(h) in the frequency characteristics. Calculations for other f(h)'s provide a group of curves. Frequency characteristics of pulmonary artery catheters were measured and overwritten thereupon, resulting in f(h)'s to be from 1.2 to 3.2 Hz. These results were in agreement with that calculated by the conventional method.