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Balloon atrial septostomy (BAS) is an essential catheterization procedure for congenital heart lesions. Recently, a balloon catheter for static BAS was approved for the first time in Japan as an alternative to the conventional pull-through BAS. Despite the expected increase in the use of static BAS, reports on its safety are scarce worldwide.Methods and Results: Data on static and pull-through BAS registered in a national registry between 2016 and 2018 were collected. During the study period, 247 sessions of static BAS and 588 sessions of pull-through BAS were performed on a total of 674 patients. Patients who underwent static BAS were older (P0.001). The incidence of serious adverse events (4.3% vs. 0.9%, P=0.03) and the overall incidence of adverse events (8.1% vs. 3.2%, P=0.03) were higher in static BAS than in pull-through BAS. Among patients who underwent static BAS, the risk factor for adverse events was a body weight3 kg at the time of the procedure (odds ratio: 4.3 [confidence interval: 1.7-11], P=0.003).This nationwide study revealed differences in patient background between static and pull-through BAS, as well as a higher incidence of adverse events related to static BAS. Patients weighing3 kg are at high risk for adverse events after static BAS and may require surgical and circulatory support backup.

Irradiation embrittlement is one of the most important phenomena in the structural integrity assessment for long-term operated reactor pressure vessels (RPVs). The causes of the irradiation embrittlement of RPVs are the formation of solute clusters and matrix defects. To investigate these embrittlement mechanisms, it is necessary to complementarily apply multiple microstructure analyses such as atom probe tomography and transmission electron microscopy. The extended X-ray absorption fine structure (EXAFS) technique can detect changes in the atomic structure by irradiation around selected atoms. In this study, we performed an EXAFS examination for RPV steels subjected to ion irradiation. We investigated microstructures of the crystal structure around specific element such as Cu, Mn, and Ni. The results indicated that the solute atoms cluster is thought to aggregate in the Fe matrix while maintaining the body-centered cubic structure and that a dumbbell pair could be located around both Cu and Ni atoms.

A powder mixture of UO2 and TiO2 was mechanochemically treated in a planetary ball mill under Ar atmosphere for 1 h using a tungsten carbide vial and balls as the milling medium. Such mechanochemical (MC) treatment reduced the crystallinity of UO2 and TiO2. The mechanochemically treated powder mixture was heated at 700–1,300°C for 6 h under Ar atmosphere and analyzed by X-ray diffraction analysis, scanning electron microscopy-energy-dispersive X-ray spectroscopy, and X-ray absorption fine structure analysis. For comparison, a UO2 and TiO2 mixture without MC treatment was heated and analyzed under the same conditions. UTi2O6 did not form below 1,100°C without MC treatment and only the starting materials were observed. At 1,200 and 1,300°C, a small amount of UTi2O6 and equal amounts of UTi2O6 and UO2 were formed, respectively. The mechanochemically treated sample produced nearly pure UTi2O6 containing small amounts of UO2 impurities when heated above 900°C for 6 h. UTi2O6 was highly crystalline and uniform regardless of the synthesis temperature. It is suggested that the crystallinity of UO2 and TiO2 was reduced and the formation of UTi2O6 was promoted by MC treatment.

Poly-ether-ether-ketone (PEEK) and carbon fiber reinforced PEEK as orthopedic implant materials exhibit excellent material properties. Although delamination of PEEK materials has been reported in knee joint wear research, the delamination resistance behavior remains unclear. In this study, the delamination resistance of PEEK materials was investigated; these materials were compared to ultra-high molecular weight polyethylene (UHMWPE). The results of a ball-on-flat type delamination test indicated that the PEEK materials underwent delamination considerably earlier than UHMWPE, and the contact area of the PEEK materials was smaller than that of UHMWPE. Moreover, the indentation modulus, hardness, and coefficient of friction were higher for PEEK materials than for UHMWPE. The reduced tendency of PEEK materials to undergo deformation to mitigate stress concentration at low conformity contact conditions contributed to their inferior delamination resistance compared to that of UHMWPE. The delamination resistance of the PEEK materials was equivalent to that of degraded UHMWPE, which highlights the risk of delamination of PEEK implants in a clinical context. Consequently, when using PEEK materials as an implant component loaded at a low conformity contact condition, the material selection and component design must be carefully considered. Overall, the results of this study can help guide the future development of PEEK-based implants.

In recent years, robotic pets have been used by many countries worldwide as a method for treating behavioral and psychological symptoms of dementia (BPSD). The seal robot PARO was loaned intermittently to a distributed layout elderly housing with services over a seven-month period, during which it was observed that three residents with cognitive dysfunctions showed improvements in their BPSD and the nursing care load of the staff was reduced during the periods when PARO was present. The objective of this study is to investigate, through a case study, the effects of intermittent interaction with PARO on those with cognitive dysfunctions and the staff workers. The short version of the Dementia Behavior Disturbance Scale (DBD-13) was used as the medical outcome index, and the KJ method was used to analyze the qualitative data, such as staff reports and interviews. The results show that the DBD-13 total scores reduced during the periods when PARO was present and increased during the periods when PARO was absent. The KJ method yielded similar findings. The use of DBD-13 and the KJ method complemented the results of each other and increased the persuasive power of the findings. By using the KJ method, it was further determined that the workload of the staff was reduced, allowing them to recuperate, which reconfirmed the value of PARO. Further case studies will be undertaken in the future with the aim of constructing a methodology for implementing case studies.

3-D magnetic recording using microwave-assisted magnetic recording (MAMR) and a spin-torque oscillator (STO) for reading has been proposed as a candidate for prospective recording technologies. In 3-D magnetic recording using STO as a reading, the temporal magnetization dynamics of the STO has the fluctuations for frequency and amplitude which depend on the recorded pattern. In our previous work, we have constructed the STO signal model considering both amplitude and frequency fluctuations to develop a combined signal processing using the amplitude and frequency fluctuation detections. We have applied the STO signal model to the low-density parity-check (LDPC) coding and iterative decoding system with the individual detectors for amplitude modulation (AM) and frequency modulation (FM). Furthermore, we have reported that the dual STO reading system with only AM detection provides the improvement of the bit error rate (BER) performance. In this study, we propose the dual STO reading system with AM–FM combined detection in the hope that the finite impulse response (FIR) filter output distribution will be easier to detect with the decoder. We evaluate the BER performances of the proposed system for carrier-to-noise ratio (CNRS) of the system noise under an areal recording density of 1 Tbits/in2 specification with bit-pattern medium stricture by computer simulation. The results show that the FIR filter output distribution for our proposed dual STO reading system at an FM detector output has become sharper, and the proposed system achieves the “No errors” with CNRS less by about 3.5 dB than the single STO reading system.

We have previously focused on a log-likelihood ratio (LLR) computed as the decoding reliability by $a$ posteriori probability (APP) decoder on the low-density parity-check (LDPC) coding and iterative decoding system for the shingled magnetic recording (SMR). Then, we clarified that the LLR modulator applying a neural network realizes an effective iterative decoding. In this article, we propose a new neural network LLR modulator considering magnetic transition information obtained from LLRs to reduce the influence of intersymbol interferences (ISIs).

A 3-D magnetic recording using microwave-assisted magnetic recording (MAMR) and a spin-torque oscillator (STO) as a reading sensor has been proposed as a candidate for the prospective recording technologies. In the STO reading system, the temporal magnetization dynamics of the STO vary not only in amplitude but also in frequency, depending on the recorded pattern. Therefore, we have constructed the STO signal model which considers both amplitude and frequency fluctuations to develop a combined signal processing using the detection of amplitude and frequency fluctuations. Furthermore, we have applied the STO signal model to the low-density parity-check (LDPC) coding and iterative decoding system with the detectors for amplitude modulation (AM) and frequency modulation (FM) and have proposed the AM–FM combined detection. Then, we have evaluated the bit error rate (BER) performances by computer simulation. The results show that the system with AM–FM combined detection improves the performance of the LDPC coding and iterative decoding system, which achieves “no errors” at the carrier-to-noise ratio for system noise (CNR $_{S}) = 15.9$ dB, whereas the AM and FM detections require CNR $_{S} = 21.2$ and 17.2 dB.

IntroductionDespite a decade of research into virtual stent deployment and the post-stenting aneurysmal hemodynamics, the hemodynamic factors which correlate with successful treatment remain inconclusive. We aimed to examine the differences in various post-treatment hemodynamic parameters between successfully and unsuccessfully treated cases, and to quantify the additional flow diversion achievable through stent compaction or insertion of a second stent.MethodsA systematic review and meta-analysis were performed on eligible studies published from 2000 to 2019. We first classified cases according to treatment success (aneurysm occlusion) and then calculated the pooled standardized mean differences (SMD) of each available parameter to examine their association with clinical outcomes. Any additional flow diversion arising from the two common strategies for improving the stent wire density was quantified by pooling the results of such studies.ResultsWe found that differences in the aneurysmal inflow rate (SMD −6.05, 95% CI −10.87 to −1.23, p=0.01) and energy loss (SMD −5.28, 95% CI −7.09 to −3.46, pConclusionsInflow rate and energy loss have shown promise as identifiers to discriminate between successful and unsuccessful treatment, pending future research into their diagnostic performance to establish optimal cut-off values.

The comparison of distant atomic clocks is foundational to international timekeeping, global positioning and tests of fundamental physics. Optical-fibre links allow the most precise optical clocks to be compared, without degradation, over intracontinental distances up to thousands of kilometres, but intercontinental comparisons remain limited by the performance of satellite transfer techniques. Here we show that very long baseline interferometry (VLBI), although originally developed for radio astronomy and geodesy, can overcome this limit and compare remote clocks through the observation of extragalactic radio sources. We developed dedicated transportable VLBI stations that use broadband detection and demonstrate the comparison of two optical clocks located in Italy and Japan separated by 9,000 km. This system demonstrates performance beyond satellite techniques and can pave the way for future long-term stable international clock comparisons. Very long baseline interferometry is used to compare two optical clocks located in Japan and Italy through the observation of extragalactic radio sources. This approach overcomes limitations of the performance of satellite transfer techniques.

Ultra-high molecular weight polyethylene (UHMWPE) is used as a bearing surface of joint prostheses and has been reported to absorb lipids such as squalene (SQ) and cholesterol esters in vivo. These lipids have been suggested by in vitro studies using SQ as a model lipid to have the potential to induce polymer degradation. However, the impact of lipid-induced degradation on the strength and wear resistance of UHMWPE is unknown. In this study, lipid-induced degradation was simulated by SQ absorption and subsequent accelerated aging, and its influence on the strength and wear resistance of UHMWPE was investigated using wear, fatigue crack growth, and delamination testing. Lipid-induced degradation was found to have little impact on fatigue crack growth rates and delamination resistance. These results were consistent with previous reports that lipid-induced degradation is localized near the surface. However, we also found that lipid-induced degradation increased the wear rate of both non-crosslinked and crosslinked UHMWPE by a factor of 2.5 and 14, respectively. These results indicate that lipid-induced degradation may affect the durability and long-term clinical outcome of joint replacements due to increased wear of UHMWPE.

Our previous work focused on a log-likelihood ratio (LLR) computed as the decoding reliability by a posteriori probability (APP) decoder in a two-dimensional magnetic recording (TDMR) system using shingled magnetic recording (SMR). In this article, we propose a neural network LLR modulator to reduce the influence of pattern dependent medium noise and to perform efficiently iterative decoding using a low-density parity-check (LDPC) code. In this study, we clarify that the performance improvement of iterative decoding can be obtained by considering LLRs of the adjacent track bits affecting the decoding bit as the input of the neural network. Furthermore, we clarify that the application of a hybrid genetic algorithm (HGA) selects LLRs by using the adjacent track LLRs affecting the decoding bit and realizes more effective iterative decoding.

To better understand the migration behavior of actinides in deep groundwater (GW), the interactions between doped tracers and deep GW components were investigated. La, Sm, Ho, and U tracers (10 or 100 ppb) were doped into sedimentary rock GW samples collected from 250 to 350 m deep boreholes in the experimental gallery of the Horonobe Underground Research Laboratory (URL), Hokkaido, Japan. To evaluate the effect of GW composition on the chemical speciation of actinides, the same tracers were doped into crystalline rock GW samples collected from 300 to 500 m deep boreholes in the experimental gallery at the Mizunami URL, Gifu Prefecture, Japan. Each GW sample was sequentially filtered through a micro-pore filter (0.2 μm) and ultrafilters with a 10 kDa nominal molecular weight limit. Next, the filtrate solutions were analyzed using inductively coupled plasma-mass spectrometry to determine the concentration of tracers retained in solution during each filtration step, and the used filters were analyzed using time-of-flight secondary ion mass spectrometry element mapping and X-ray absorption fine structure spectroscopy to determine the chemical species of the tracers trapped on each filter. It was determined that lanthanide migration was controlled by the amount of phosphates in the Horonobe GW. Therefore, it was expected that the solubility of minor actinides (MAs), which exhibit a similar chemical behavior to that of lanthanides, would be controlled by the formation of phosphates in sedimentary rock GW. Moreover, the data on the Mizunami GW indicated that a fraction of lanthanides and MAs formed hydroxides and/or hydroxocarbonates.

The 3-D magnetic recording using the microwave-assisted magnetic recording and a spin-torque oscillator as a reading sensor has been proposed as a candidate of the prospective recording technologies. In our previous research, we have constructed the read/write channel of the envelope model to evaluate a variety of signal processing for the 3-D magnetic recording. In this paper, we apply the low-density parity-check coding and iterative decoding system including turbo equalization to the 3-D magnetic recording channel model with dot position fluctuation and evaluate the bit error rate performance by the computer simulation. The results clarify that the tolerance of dot position fluctuation which “no errors” is able to be achieved.

This paper focuses on the shingled magnetic recording (SMR) as the recording system for further high-density hard disk drives. Previously, we applied a log-likelihood ratio (LLR) modulator to the low-density parity check coding and iterative decoding system in SMR to improve the decoding performance. In this paper, we propose a new LLR modulator using neural network. Furthermore, we clarify that the proposed LLR modulator using neural network realizes effective iterative decoding in a read/write channel with pattern-dependent medium noise.

We study the low-density parity-check (LDPC) coding and iterative decoding system, as a signal processing system for the shingled magnetic recording (SMR) in two-dimensional magnetic recording (TDMR). Previously we reported that a waveform equalization using a two-dimensional finite impulse response (TD-FIR) filter or an inter-track interference (ITI) canceler reduced the influence of ITI. We also proposed a neural network detector (NND), and evaluated the performance of the first decoding by the NND. In this paper, we propose the NND which iteratively calculates the log-likelihood ratio (LLR) as the decoding reliability using the returned sum-product (SP) decoder output sequence in addition to the TD-FIR filter output sequence. Furthermore, we evaluate the performance of the iterative decoding system using an NND, and compare it to that of the system using a soft-output Viterbi algorithm (SOVA) detector with the signal-dependent noise predictor.

To further increase areal recording density in hard disk drives (HDD), we study a three-dimensional (3D) magnetic recording system with double recording layers and the magnetoresistive (MR) read-sensors. We constructed a read/write channel model that combines an ideal double recording layers with MR reading sensors to evaluate a 3D magnetic recording. In this study, we have evaluated the bit error rate (BER) performance of the generalized partial response (GPR) maximum likelihood (ML) (GPRML) system for the samples captured at the phases of the bit center and boundary under total areal recording density of 8 Tbits/inch2 on a dual recording layers medium (Each areal recording density is 4 Tbit/inch2). As the results, it is certified that the GPRML system for the reproducing waveforms captured at phases of the bit center offers better BER performance compared with that of the bit boundary.

Background Stent implantation for vascular stenosis associated with congenital heart diseases is commonly performed as an off-label procedure in Japan because there is no officially approved stent for any congenital heart disease.Methods and Results:We analyzed data from the Japanese Society of Congenital Interventional Cardiology Registry collected from January 2016 to December 2018. Patients who underwent stent implantation were enrolled in the present analysis. During the study period, there were 470 procedures, 443 sessions, and 391 cases. Of 443 sessions, 427 (96.4%) succeeded procedurally. There were no differences in the procedural success rates among age groups. In all, 416 sessions (367 patients; 94%) resulted in survival to 30 days after catheter intervention. Of 392 admissions, 357 patients (91%) survived to discharge. Only 4 deaths were directly related to stent implantation. Some in-hospital complications were observed during 55 of 443 sessions. Both hospital deaths and serious complications were significantly more frequent in the group with various preoperative risk factors. Conclusions Although not officially approved for congenital heart diseases in Japan, stent implantation in congenital heart diseases has been widely and routinely performed for many years with safety and efficacy. The aim of stenting was variable and broad because of many different applications and morphological variations. These data may facilitate approval of such an important device in Japan.

For the aim to enable precise frequency transfer over earth radius scale distance, NICT developed a broadband VLBI system observing 3-14 GHz radio frequency range, and that was implemented in a pair of transportable 2.4m diameter VLBI stations and Kashima 34m diameter VLBI station. The small diameter VLBI stations installed in Medicina observatory of INAF (Italy) and NICT headquarters in Koganei (Japan) were used compare the atomic frequency standards. The poor sensitivity of VLBI observation with the small antenna pair was compensated by participation of the large diameter antenna for boosting the signal to noise ratio (SNR) of the VLBI observation. Owing to the broad observing frequency range, a few pico seconds precision of group delay is achieved on intercontinental baseline even with small diameter antenna. Advanced digital data acquisition with highspeed 16 GHz sampling enabled stable group delay measurement. A series of frequency transfer experiments was conducted during Oct. 2018 – Feb. 2019 by using the broadband VLBI system between ytterbium (Yb) optical lattice clock of INRiM (Italy) and strontium (Sr) lattice clock of NICT(Japan) separated by 9000km. The deviation of fractional frequency ratio between Yb and Sr was obtained by VLBI observation as y(Yb/Sr)=2.5(2.8)x10-16. The uncertainty in this experiment is evaluated not to be limited by the VLBI link itself, and further improvement is expected. Prospect of VLBI frequency link and uncertainty budget in VLBI observation is discussed in this report.

Olfaction is notorious as a vague and ambiguous sense. Some researches proposed a method that takes advantage of the feature to present more kinds of odors than the actual number of fragrances. However, it is still unclear what kind of factors affect the optimization of olfactory modulation. This paper investigated the effect of differences in methods to present heat sensation including presentation setups, areas, and positions of heat sensation. The heat sensation is stimulated by air flow and metal contact with a fan heater or a Peltier device. The heat sensation is presented to either apex of nose, philtrum, left cheek, or right cheek. In the experiment, the subjects were instructed to answer the scores to the odor of R-(+)-limonene and the odorless air presented with heat sensation compared to the odor impressions at room temperature by Likert scale questionnaire for the 8 adjective pairs. The experimental results suggested that the perceived odor impressions of R-(+)-limonene differed strongly depending on the presentation methods other than the presented temperature and humidity. In particular, presenting in a large area around the nose are considered more capable of modulating odor perception than the other methods.

We have previously proposed the waveform equalization using a two-dimensional finite impulse response (TD-FIR) filter and the inter-track interference (ITI) canceller as a signal processing method for shingled magnetic recording (SMR) system. In this study, we propose a neural network detector (NND) to automate the iterative decoding in the future and evaluate the performance of the NND in SMR system. The result shows that our proposed NND shows almost the same performances as a combined system with TD-FIR filter and soft-output Viterbi algorithm (SOVA) detector with signal-dependent noise predictor.