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A woman in her late 70 s was diagnosed with liver injury at a health examination. Despite treatment with ursodeoxycholic acid at a nearby hospital, her transaminase levels elevated in two peaks. She was transferred to our hospital 77 days after the health examination. She weighed 42 kg and had a low body mass index of 19.8 kg/m

A 70-year-old man with multicentric Castleman disease (MCD) was admitted to our hospital with jaundice and ascites. Elevations in his bilirubin and interleukin-6 levels were noted, and computed tomography revealed hepatic atrophy and portal vein and bile duct disorders. Steroid therapy was started for MCD, but he died of hepatic failure. An autopsy revealed that the MCD activity was mild, but advanced fibrosis and cholestasis were observed in the liver. Mild infiltration of interleukin-6-positive plasma cells was noted in the highly fibrotic area of the liver. Although rare, liver and biliary tract damage may be also considered organ disorders of MCD.

Each superconductor logic family has distinct features and advantages. For instance, adiabatic quantum-flux-parametron (AQFP) circuits operate with very high energy efficiency, and rapid single-flux-quantum (RSFQ) circuits operate at very high clock frequencies. To build a hybrid system that combines the above advantages, we propose a compact interface between AQFP and RSFQ circuits that converts current signals in AQFP logic into flux signals in RSFQ logic using a non-adiabatic quantum-flux-parametron gate. Compared to a previously proposed AQFP/RSFQ interface, the proposed interface has far fewer Josephson junctions (4 vs. 11). We optimize the circuit parameters of the AQFP/RSFQ interface and demonstrate the interface at low speed as proof of concept. Furthermore, we demonstrate data propagation between AQFP circuits along a long passive transmission line via the AQFP/RSFQ interface at low speed to show that the AQFP/RSFQ interface can alleviate the interconnect length limit in AQFP circuits.

We report on boron-related defects in the low-doped n-type (nitrogen-doped) 4H-SiC semitransparent Schottky barrier diodes (SBDs) studied by minority carrier transient spectroscopy (MCTS). An unknown concentration of boron was introduced during chemical vapor deposition (CVD) crystal growth. Boron incorporation was found to lead to the appearance of at least two boron-related deep-level defects, namely, shallow (B) and deep boron (D-center), with concentrations as high as 1 × 1015 cm−3. Even though the boron concentration exceeded the nitrogen doping concentration by almost an order of magnitude, the steady-state electrical characteristics of the n-type 4H-SiC SBDs did not deteriorate.

Negatively charged silicon vacancy (VSi−) defects in silicon carbide are expected to be used for magnetic sensors under harsh environments, such as space and underground due to their structural stability and potential for high-fidelity spin manipulation at high temperatures. To realize VSi− based magnetic sensors operating at high temperatures, the temperature dependence of optically detected magnetic resonance (ODMR) in the ground states of VSi− defects, which is the basic principle of magnetic sensing, should be systematically understood. In this work, we demonstrate the potential of VSi− magnetic sensors up to at least 591 K by showing the ODMR spectra with different temperatures. Furthermore, the resonance frequency of the ground level was independent of temperature, indicating the potential for calibration-free magnetic sensors in temperature-varying environments. We also characterize the concentration of VSi− defects formed by electron irradiation and clarify the relationship of magnetic sensing sensitivity to VSi− concentration and find that the sensing sensitivity increases linearly with VSi− concentration up to at least 6.0 × 1016 cm−3. The magnetic sensitivity at a temperature above 549 K was reduced by half as compared to that at 300 K. The results pave the way for the use of a highly sensitive VSi−-based magnetic sensor under harsh environments.

Background : The aim of this retrospective study was to determine whether tolvaptan treatment reduces the amount of albumin administered, volume of ascites removed, and frequency of paracentesis procedures in patients with decompensated cirrhosis with uncontrolled ascites with conventional diuretics. Patients and methods : The control (C) group included patients treated with conventional diuretics. The tolvaptan (T) group included patients treated with both tolvaptan and conventional diuretics. Both groups were matched according to baseline parameters. The amount of albumin administered, volume of ascites removed, and frequency of paracentesis within 30 days of onset of uncontrolled ascites were compared between the two groups. Results : After matching, 74 patients (C=37, T=37) were included. Baseline parameters (C vs. T group) were as follows : age, 69.5 ± 9.3 vs. 70.4 ± 11.0 years (p = 0.702) ; males, 24 (64.9%) vs. 25 (67.6%) (p = 0.999) ; patients with hepatocellular carcinoma, 17 (45.9%) vs. 18 (48.6%) (p = 0.999) ; serum albumin levels at treatment initiation, 2.76 ± 0.48 vs. 2.73 ± 0.49 g/dL (p = 0.773), and serum creatinine levels at treatment initiation, 1.18 ± 1.23 vs. 1.09 ± 0.48 g/dL (p = 0.679). In the C vs. T groups, respectively, mean amount of albumin administered was 51.0 ± 31.4 vs. 33.4 ± 29.8 g/month (p = 0.016) ; mean volume of ascites removed was 2,905 ± 4,921 vs. 1,824 ± 3,185 mL/month (p = 0.266) ; and mean frequency of paracentesis was 0.92 ± 1.46 vs. 0.89 ± 1.45 procedures (p = 0.937). Conclusions : Tolvaptan reduced the use of albumin infusion in patients with decompensated cirrhosis and was effective and acceptable for uncontrolled ascites.

Silicon vacancies (Vsi) in silicon carbide (SiC) have attracted attention because they can be used for quantum sensors (F. Fuchs et al., Nat. Com. 6: 7578 (2015)). We aim to develop Vsi magnetic sensors operating at high temperatures because of its structural stability. However, change with temperatures, especially high temperature, in optically detected magnetic resonance (ODMR) in the ground state of Vsi, which is the basic principle of magnetic sensing, is less well understood. Here, we report the change in ODMR spectra of Vsi with different temperatures., Defects in solids for quantum technologies(DSQT)

We examined 171 patients with novel coronavirus disease 2019 (COVID-19) with liver injury in the respiratory failure groups and the nonrespiratory failure groups and investigated 41 patients with moderate II COVID-19 with respiratory failure who received dexamethasone (Dex) monotherapy in the liver injury group and the nonliver injury group at the time before treatment. The respiratory failure group had 64% more liver damage than the nonrespiratory failure group, was older, had more men, and had significantly more complications from lifestyle-related diseases such as hypertension and diabetes. Obesity was more common in the liver injury group prior to Dex monotherapy, and the liver CT value was significantly lower than in the nonliver injury group. Liver injury worsened in 41% of patients after Dex monotherapy, but there was no significant difference in the frequency before Dex monotherapy between the liver injury group and the nonliver injury group, and the degree of liver injury was mild in all cases, improving in 38% of the liver injury group. Dex monotherapy was a safe treatment for moderate II COVID-19, which frequently resulted in liver injury.

Spin defects of which states can be manipulated in Silicon Carbide (SiC) have drawn considerable attention because of their applications to quantum technologies. The single negatively-charged pairs of VSi and nitrogen atom (N) on an adjacent C site (NcVsi- center) in SiC is suitable for them. This paper reports the formation of NcVsi- centers on 4H-SiC epilayers with different nitrogen concentrations using light/heavy ion irradiation and subsequent thermal annealing. The formation of NcVsi- centers is characterized by the near infrared photoluminescence (PL) spectroscopy. It is shown that the PL intensity from NcVsi- centers depends on the N concentration and the ion irradiation conditions. The PL intensity increases monotonically with increasing the N concentration when the N concentration is above 2.6×10^16 cm^-3 , whereas no linear correlation between them does not appear below that N concentration. Although the PL intensity increases with increasing defects induced by ion irradiation, the PL quenching due to neighboring residual defects appear at above the areal vacancy concentration of 10^17 vac/cm^2 and the broad Raman scattering spectra originated from vibration modes of amorphized regions hinder the PL from NcVsi- centers at above 10^18 vac/cm^2. The formation mechanism and the charge state stability of NcVsi- centers are discussed based on the obtained results.

BACKGROUND Sodium glucose cotransporter 2 (SGLT2) inhibitors are newly developed oral antidiabetic drugs. SGLT2 is primarily expressed in the kidneys and reabsorbs approximately 90% of the glucose filtered by the renal glomeruli. SGLT2 inhibitors lower glucose levels independently of insulin action by facilitating urinary glucose excretion. The SGLT2 inhibitor ipragliflozin has reportedly improved liver steatosis in animal models and clinical studies. However, the mechanisms by which SGLT2 inhibitors improve liver steatosis are not fully understood. AIM To investigate the ameliorative effects of ipragliflozin on liver steatosis and the mechanisms of these effects in obese mice. METHODS We analyzed 8-wk-old male obese (ob/ob) mice that were randomly divided into a group receiving a normal chow diet and a group receiving a normal chow diet supplemented with ipragliflozin (3 mg/kg or 10 mg/kg) for 4 wk. We also analyzed their lean sex-matched littermates receiving a normal chow diet as another control group. Body weight and liver weight were evaluated, and liver histology, immunoblotting, and reverse transcription-polymerase chain reaction analyses were performed. RESULTS Hepatic lipid accumulation was significantly ameliorated in ob/ob mice treated with 10 mg/kg ipragliflozin compared to untreated ob/ob mice irrespective of body weight changes. Ipragliflozin had no appreciable effects on hepatic oxidative stress-related gene expression levels or macrophage infiltration, but significantly reduced hepatic interleukin-1β (IL-1β) mRNA expression levels. Ipragliflozin increased both the mRNA and protein expression levels of sirtuin 1 (SIRT1) in the liver. The hepatic mRNA levels of peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α), peroxisome proliferator-activated receptor α (PPARα), and fibroblast growth factor-21 (FGF21) were also significantly higher in ipragliflozin-treated ob/ob mice than in untreated ob/ob mice. CONCLUSION Our study suggests that the liver steatosis-ameliorating effects of ipragliflozin in ob/ob mice may be mediated partly by hepatic SIRT1 signaling, possibly through the PGC-1α/PPARα-FGF21 pathway.

Silicon carbide junction field effect transistors (SiC JFETs) were irradiated with gamma-rays up to 9 MGy (H2O). With increasing dose, apparent shift of drain current-gate voltage (ID-VG) curves to negative voltage side as observed for SiC metal oxide semiconductor (MOS) FETs did not take place. No significant difference is observed between drain and gate leakage currents of irradiated JFETs. This strongly indicates that defects as leakage paths were introduced into not bulk region but the interface between bulk and the passivation layer of SiO2. While, the transfer characteristics including threshold voltage and transconductance were slightly changed compared with the pristine sample. After drain voltage (VD) was abruptly applied to 6 V, ID at VG= 0 V increased slowly as a function of time. This indicates that variation of transfer characteristics is attributed to capture and emission process at defects generated in channel region.

Spin defects of which states can be manipulated in Silicon Carbide (SiC) have drawn considerable attention because of their applications to quantum technologies. The single negatively-charged pairs of VSi and nitrogen atom (N) on an adjacent C site (NCVSi- center) in SiC is suitable for them. This paper reports the formation of NCVSi- centers on 4H-SiC epilayers with different nitrogen concentrations using light/heavy ion irradiation and subsequent thermal annealing. The formation of NCVSi- centers is characterized by the near infrared photoluminescence (PL) spectroscopy. It is shown that the PL intensity from NCVSi- centers depends on the N concentration and the ion irradiation conditions. The PL intensity increases monotonically with increasing the N concentration when the N concentration is above 2.6×1016 cm-3, whereas no linear correlation between them does not appear below that N concentration. Although the PL intensity increases with increasing defects induced by ion irradiation, the PL quenching due to neighboring residual defects appear at above the areal vacancy concentration of 1017 vac/cm2 and the broad Raman scattering spectra originated from vibration modes of amorphized regions hinder the PL from NCVSi- centers at above 1018 vac/cm2. The formation mechanism and the charge state stability of NCVSi- centers are discussed based on the obtained results.

We investigated the effects of γ-ray irradiation to single photon sources (SPSs) embedded in 4H-SiC metal-oxide-semiconductors field-effect transistors (MOSFETs). After the γ-ray irradiation, the number of SPSs was temporarily increased. However, the ratio of unstable SPSs was increased with increasing the radiation dose, and such unstable ones gradually disappeared. Finally, the density of the SPSs nearly recovered that before the irradiation. We discuss a possible explanation on these phenomena in terms of interactions between mobile hydrogen atoms and interface defects.

We demonstrated the enhancement of the optically detected magnetic resonance (ODMR) contrast of negatively charged silicon vacancy (VSi-) in SiC by thermal treatment. To create high density VSi-, Proton Beam Writing (PBW) was conducted. After an annealing at 600 °C, ODMR contrast showed the highest value in the investigated temperature range. At a fewer irradiation fluence, despite no significant change was observed in terms of VSi- PL intensity, the improvement of the ODMR contrast was observed. Considering defect energy levels and annealing behavior previously reported, it was deduced that the improvement of the ODMR contrast was caused by the reduction of other irradiation induced defect centers, such as EH1/EH3 centers.

We demonstrated optically detected magnetic resonance (ODMR) measurements using three-dimensional (3D) arrayed silicon vacancies (VSis) in in-plane SiC pn diodes. Proton beam writing successfully created 3D arrayed VSis using different ion (proton) energies. The results of PL mapping analysis indicate that the features of luminescent spot such as size and depth can be estimated by a Monte Carlo simulation (SRIM). This suggests that diagnosis at any locations in SiC devices can be realized using VSi quantum sensors. Luminescent spots with different depth ranging 4-60 μm showed similar ODMR spectra including its contrast, which means that a similar sensor sensitivity is expected. The results suggest that 3D arrayed VSi can act as quantum sensor elements with uniform sensitivity in SiC devices.

炭化ケイ素中のシリコン空孔(Vsi)は、磁場や温度を高感度に検出できる「量子センサ」としての応用が期待されている。Vsiは高エネルギー電子線照射によって形成することができ、センサ感度はVsiの数(濃度)に依存するが、実用化のためにはVsi濃度の定量が重要となる。また、電子線照射によってデコヒーレンスの原因となる不要な照射欠陥も同時に形成されるため、その影響を明らかにするとともに低減する手法を確立する必要がある。本研究では、電子スピン共鳴(ESR)測定より、電子線照射量に対するVsi形成濃度を定量化するとともに、磁気センシングの基本原理である光検出磁気共鳴(ODMR)スペクトルの変化を調べ、照射欠陥の影響について検討した。高純度半絶縁性4H-SiC基板に2 MeV電子線を最大3.0×1018 cm-2まで照射し、Vsiを形成した。その後、真空中600℃で30分間の熱処理を行い、Vsi以外の不要な欠陥を低減した(Y. Chiba et al., Mater. Sci. Forum 1004, 337 (2020).) 。Fig.1(a)は3.0×10^18 cm-2照射した試料の室温でのESRスペクトルであり、(b)は室温ESR測定により同定した電子線照射量に対するVsi濃度の変化を示している。Vsi起因のESR信号は電子線照射量に対し比例関係にあると考えVsi収率を算出すると、未熱処理試料では5.7×10^(-3) cm^(-1) 、熱処理試料では3.6×10^(-3) cm^(-1) となった。講演では、Vsi濃度に対するODMRスペクトル（磁気感度）の変化について議論する。, 第69回応用物理学会春季学術講演会

炭化ケイ素(SiC)中のシリコン空孔(VSi)は磁気や温度を高感度に検出する「量子センサ」として注目されており、特に、VSiは高温下でも安定して存在するため、宇宙や地底といった厳環境に対応できる高感度磁気センサなどへの応用が期待できる。しかし、磁気センシングの基本原理となる光検出磁気共鳴(ODMR)現象の高温下での振る舞いは明らかになっていない。また、VSiは高エネルギー電子線照射によって形成するが、デコヒーレンスの要因となる不要な欠陥も同時に形成され、その影響も考慮しなければならない。そこで本研究では、ODMR スペクトルに対するVSi形成量及び測定温度依存性を系統的に調査した。さらに、磁気感度評価を行い、シリコン空孔量子センサの実現に向けた新たな知見を示した。, 第 11 回 半導体・超電導量子コテレンスと量子情報参加の為

Negatively charged boron vacancy (V B –) in hexagonal boron nitride has attracted attention as a promising spin defect for quantum sensing applications. Hence, a fabrication method for generation of V B – with superior spin properties would be desirable. In this study, we demonstrated V B – formation by two thermal treatment methods. Both methods improve the signal-to-noise ratio of optically detected magnetic resonance signal by a factor of 4. Furthermore, a zero-field splitting parameter E which reflects crystal distortion after irradiation significantly reduces for irradiation above 650 °C. These findings indicate that thermal treatment is an effective method for a V B – based quantum sensor.

A 66-year-old man, who had undergone plasma exchange 30 years previously in Egypt for the treatment of falciparum malaria, was referred to our hospital for treatment of chronic hepatitis C (HCV). An analysis of the 655-nucleotide 5'-untranslated region-core region sequence revealed infection with HCV subtype 1g. A phylogenetic analysis of the full-length HCV genome confirmed that the patient's HCV was subtype 1g, which was the first case identified in Japan. Although his HCV possessed several naturally occurring resistance-associated substitutions in the nonstructural (NS) 3 and NS5A regions, he was successfully treated by combination therapy with glecaprevir/pibrentasvir.

Silicon vacancy (VSi) centers in silicon carbide have attracted attention because of their potential applications to quantum sensors (high-sensitivity magnetic field and temperature sensors). VSi centers are also expected to be used for magnetic sensors under harsh environments such as space and undergrounds, since they have structural stability and the potential of high-fidelity spin manipulation at high temperatures. To realize VSi based magnetic sensors operating at high temperature, understanding of optically detected magnetic resonance (ODMR) in the ground states of VSi centers, which is the basic principle of magnetic sensing, is crucial. In particular, the effects of temperature on the ODMR spectra are less well understood. Here, we demonstrate the potential of VSi magnetic sensors at high temperatures by showing the ODMR spectra with different temperatures. We also systematically investigate the effects of high energy electron irradiations on the ODMR spectra of formed VSi centers. The concentration of VSi centers increases with increasing electron irradiation dose, resulting in the enhancement of sensitivity, but the increase of undesired defects which might cause decoherence is also considered. Hence, the effects of electron irradiation dose should be clarified to obtain better sensitivity of VSi based magnetic sensors., The 4th International Forum on Quantum Metrology and Sensing

Direct energy conversion has been investigated using Ni/SiC Schottky junctions with the irradiation of monochromatized synchrotron x rays mimicking the gamma rays of 237Np (30 keV) and 241Am (60 keV). Through current–voltage measurements, electrical energies were obtained for both types of gamma rays. The energy conversion efficiencies based on absorbed energy were found to be ∼1.6%, which is comparable to other previously described semiconducting systems. This result raises the prospect of energy recovery from nuclear wastes utilizing the present system, judging from the radiation tolerant nature of SiC. Additionally, we found different conversion efficiencies between the two samples during the same process. This could be explained using hard x-ray photoelectron spectroscopy and secondary ion mass spectroscopy measurements, suggesting the creation of Ni–Si compounds at the interface in the sample with poor performance. Hence, such combined measurements are useful to provide data that electrical measurements cannot provide us.

炭化ケイ素(SiC)中のシリコン空孔(VSi−)は磁気や温度を高感度に検出する「量子センサ」として注目されており、特に、VSi−は高温下でも安定して存在するため、宇宙や地底といった厳環境に対応できる高感度磁気センサなどへの応用が期待できる。しかし、磁気センシングの基本原理となる光検出磁気共鳴(ODMR)現象の高温下での振る舞いは明らかになっていない。また、VSi−は高 エネルギー電子線照射によって形成するが、デコヒーレンスの要因となる不要な欠陥も同時に形成され、その影響も考慮しなければならない。そこで本研究では、ODMR スペクトルに対するVSi−形成量及び測定温度依存性を系統的に調査した。高純度半絶縁性4H-SiC 基板に2 MeV 電子線を照射してVSi−を形成した。その後、真空中600 ℃で30 分間の熱処理を行い、VSi−以外の不要な欠陥を低減した。その脚気、70 MHz に基底準位のゼロ磁場分裂に起因する共鳴ピークが確認できた。しかし、高温ではコントラスト(ピーク高)が低下すると共に半値幅が増加したため、磁気感度は低下することが予想される。, 第82回応用物理学会秋季学術講演会

SiCデバイス中に作製したシリコン空孔量子センサーを用いて電流誘起磁場を直接測定した, 応用物理学会秋季学術講演会

Investigational treatments/drugs for coronavirus disease 2019 (COVID-19) have been applied, with repurposed or newly developed drugs, and their effectiveness has been evaluated. Some of these drugs may be hepatotoxic, and each monotherapy or combination therapy may increase the risk of drug-induced liver injury (DILI). We should aim to control dysregulation of liver function, as well as the progression of COVID-19, as much as possible. We discussed the potential risks of investigational treatments/drugs and promising drugs for both COVID-19 and DILI due to investigational treatments/drugs.

Although direct-acting antiviral (DAA)-based anti-hepatitis C virus (HCV) therapies are very effective for patients with genotypes 1 and 2, evidence of the efficacy of DAA-based therapy for the special population of patients with genotypes 3-6 is insufficient due to the relatively small number of these subjects in Japan. Human immunodeficiency virus (HIV)/HCV-co-infected patients are recommended to be treated as HCV-mono-infected patients by the latest version of the Japan Society of Hepatology guidelines. However, evidence of efficacy in patients with HIV/HCV genotype 3-6 co-infection is insufficient. Currently, HCV genotypes 3-6 can be treated with two DAA-based therapies, including glecaprevir (GLE)/pibrentasvir (PIB) therapy in Japan. We experienced a relatively rare case of a Japanese hemophilia patient co-infected with HIV/HCV genotype 4a. We evaluated resistance-associated substitutions (RASs) against GLE and PIB before GLE/PIB therapy and found that he had no RASs. He was treated with 12 weeks of GLE/PIB therapy and achieved a sustained virologic response at post-treatment weeks 24. Although the treatment was well tolerated, the patient developed hyper-low-density lipoproteinemia that was probably associated with HCV elimination during the therapy. Additional studies are needed to confirm the efficacy and safety of GLE/PIB therapy for this special population in Japan.

Noonan syndrome is a genetic multisystem disorder and is associated with mutation of genes encoding the proteins in the RAS‐MAPK pathway. We reported the first case of Noonan syndrome complicated with hepatocellular carcinoma.

We demonstrated that silicon vacancy (VSi) can be created in SiC pn junction diode by proton beam writing (PBW) without degradation of the diode performance. The VSi showed the same specific emission for both optically and electrically excitation, which suggests that electrically controllable VSi was created. In addition, optically detected magnetic resonance (ODMR) signal was successfully detected from optically excited VSi at room temperature. This result suggests that VSi introduced into the device by PBW still maintain spin manipulating capability, which is an important step toward realizing SiC devices internally equipped with a VSi-based quantum sensor.

BACKGROUND The effectiveness of sofosbuvir/ribavirin (SOF/RBV) combination therapy, which is one of the 1st-choice therapeutic options for patients with hepatitis C virus (HCV) genotype 2 (HCV-G2) in Japan according to the most recent version of the Japan Society of Hepatology guideline, for patients who experienced failure of the ombitasvir/paritaprevir/ritonavir plus ribavirin (OBV/PTV/r+RBV) combination therapy, which was another option for patients with HCV-G2, is unknown. CASE SUMMARY We evaluated the effects of SOF/RBV combination therapy in two patients with genotype 2a who could not achieve a sustained virological response (SVR) by OBV/PTV/r+RBV combination therapy. One patient was complicated with Vogt-Koyanagi-Harada (VKH) disease. Resistance-associated variations before SOF/RBV combination therapy were not detected in two patients. Both patients had an SVR at 12 wk after the treatment (SVR12). Regarding adverse events (AEs), itching, chill, a dull feeling in the throat and cough as well as increase of alanine transaminase level were shown in one patient, while a headache and deterioration of light aversion probably due to the recurrence of VKH disease were shown in the other patients. In addition, the latter patient developed arthralgia and morning stiffness approximately 7 wk after the therapy and turned out to be diagnosed with rheumatoid arthralgia. CONCLUSION SOF/RBV therapy might be effective for patients experiencing failure of OBV/PTV/r+RBV therapy, but caution should be taken regarding the AEs.

Correlative microscopy and block-face imaging (CoMBI), a method that we previously developed, is characterized by the ability to correlate between serial block-face images as 3-dimensional (3D) datasets and sections as 2-dimensional (2D) microscopic images. CoMBI has been performed for the morphological analyses of various biological specimens, and its use is expanding. However, the conventional CoMBI system utilizes a cryostat, which limits its compatibility to only frozen blocks and the resolution of the block-face image. We developed a new CoMBI system that can be applied to not only frozen blocks but also paraffin blocks, and it has an improved magnification for block-face imaging. The new system, called CoMBI-S, comprises sliding-type sectioning devices and imaging devices, and it conducts block slicing and block-face imaging automatically. Sections can also be collected and processed for microscopy as required. We also developed sample preparation methods for improving the qualities of the block-face images and 3D rendered volumes. We successfully obtained correlative 3D datasets and 2D microscopic images of zebrafish, mice, and fruit flies, which were paraffin-embedded or frozen. In addition, the 3D datasets at the highest magnification could depict a single neuron and bile canaliculus.

Dual-band infrared photodetectors with a modified pBp design have been demonstrated. The modified pBp structure consisted of a p-type InAs/GaSb superlattice for long-wavelength (LW) detection and a p-type InAs/GaSb/AlSb based superlattice for mid-wavelength (MW) detection, which were separated by a hole barrier consisting of an InAs/AlSb superlattice. Our pBp device showed that dual-band detection was possible by changing the bias polarity of the applied voltage. By using an InAs/GaSb/AlSb based superlattice as an MW absorber for a pBp photodetector, a 100 % cutoff wavelength was blue-shifted from 8 μm to 7 μm compared with a conventional InAs/GaSb superlattice, while maintaining the same 50 % cutoff wavelength of around 6.4 μm. Quantum efficiency per period of the modified MW absorber was comparable with that of a conventional MW absorber. These results indicate that our modified pBp structure is expected to be a promising candidate for dual-band infrared photodetectors.

量子技術の応用でもっとも産業化が早いと目されている量子計測・センシング技術の最新研究を概観

In the last two decades we have assisted to a rush towards finding a 3He-replacing technology capable of detecting neutrons emitted from fissile isotopes. The demand stems from applications like nuclear war-head screening or preventing illicit traffic of radiological materials. Semiconductor detectors stand among the strongest contenders, particularly those based on materials possessing a wide band gap like silicon carbide (SiC). We review the workings of SiC-based neutron detectors, along with several issues related to material properties, device fabrication and testing. The paper summarizes the experimental and theoretical work carried out within the E-SiCure project (Engineering Silicon Carbide for Border and Port Security), co-funded by the NATO Science for Peace and Security Programme. The main goal was the development of technologies to support the fabrication of radiation-hard silicon carbide detectors of special nuclear materials. Among the achievements, we have the development of successful Schottky barrier based detectors and the identification of the main carrier life-time-limiting defects in the SiC active areas, either already present in pristine devices or introduced upon exposure to radiation fields. The physical processes involved in neutron detection are described. Material properties as well as issues related to epitaxial growth and device fabrication are addressed. The presence of defects in as-grown material, as well as those introduced by ionizing radiation are reported. We finally describe several experiments carried out at the Jozef Stefan Institute TRIGA Mark II reactor (Ljubljana, Slovenia), where a set of SiC-based neutron detectors were tested, some of which being equipped with a thermal neutron converter layer. We show that despite the existence of large room for improvement, Schottky barrier diodes based on state-of-the-art 4 H -SiC are closing the gap between gas- and semiconductor-based detectors regarding their sensitivity.

In 2016, the “E-SiCure” project (standing for “Engineering Silicon Carbide for Border and Port Security”), funded by the NATO Science for Peace and Security Programme was launched. The main objective is to combine theoretical, experimental and applied research towards the development of radiation-hard SiC-based detectors of special nuclear materials (SNM), with the end goal to enhance border and port security barriers. Prototype neutron detectors, configured as 4H-SiC-based Schottky barrier diodes, were developed for the detection of secondary charged particles (tritons, alphas and lithium atoms) which are the result of thermal neutron reactions on 10B and 6LiF layers above the surface of the 4H-SiC diodes. We designed a stand-alone prototype detection system, consisting of a preamplifier, shaping amplifier and a multichannel analyser operated by a laptop computer, for testing of neutron detector prototypes at the Jožef Stefan Institute (JSI) TRIGA reactor using a broad beam of reactor neutrons. The reverse bias for the detector diode and the power to electronic system were provided by a standalone battery-powered voltage source. The detector functionality was established through measurements using an 241Am alpha particle source. Two dedicated experimental campaigns were performed at the JSI TRIGA reactor. The registered pulse height spectra from the detectors, using both 10B and 6LiF neutron converting layers, clearly demonstrated the neutron detection abilities of the SiC detector prototypes. The computed neutron detection sensitivity of the single prototype detectors demonstrates that scaling SiC detectors into larger arrays, of dimensions relevant for border and port radiation detectors, could enable neutron sensitivity levels matching gas-based detector technology.