Giant gate-controlled odd-parity magnetoresistance in one-dimensional channels with a magnetic proximity effect.

According to Onsager's principle, electrical resistance R of general conductors behaves as an even function of external magnetic field B. Only in special circumstances, which involve time reversal symmetry (TRS) broken by ferromagnetism, the odd component of R against B is observed. This unusual phenomenon, called odd-parity magnetoresistance (OMR), was hitherto subtle (< 2%) and hard to control by external means. Here, we report a giant OMR as large as 27% in edge transport channels of an InAs quantum well, which is magnetized by a proximity effect from an underlying ferromagnetic semiconductor (Ga,Fe)Sb layer. Combining experimental results and theoretical analysis using the linearized Boltzmann's equation, we found that simultaneous breaking of both the TRS by the magnetic proximity effect (MPE) and spatial inversion symmetry (SIS) in the one-dimensional (1D) InAs edge channels is the origin of this giant OMR. We also demonstrated the ability to turn on and off the OMR using electrical gating of either TRS or SIS in the edge channels. These findings provide a deep insight into the 1D semiconducting system with a strong magnetic coupling.

Pairing of white wine made with shade-grown grapes and Japanese cuisine.

This study investigated the effect of pairing of wine vinified from shade-grown grapes before onset of ripening on the palatability of sashimi, a typical Japanese cuisine. GC-MS analyses of volatile chemicals revealed that shading reduced phenolic compounds and terpenoids, and added fatty acid ethyl esters which are also known to contribute to the flavor of Japanese sake. When the pairing of sashimi with wine was evaluated by individuals who regularly drink Japanese sake during meals, shade wine was more highly rated than wine made from normally-grown grapes.

Development of dual bias modulation electrostatic force microscopy for variable frequency measurements of capacitance.

We propose dual bias modulation electrostatic force microscopy (DEFM) for variable frequency measurements of surface depletion capacitance on a semiconductor. In DEFM, dual alternating current bias voltages at angular frequencies of ω1 and ω2 are applied to generate an electrostatic force, and we detect the high order term at an angular frequency of ω2 - 2ω1 in the electrostatic force from which a derivative of surface depletion capacitance by voltage (∂C/∂V) can be evaluated. Even with a fixed value of ω2 - 2ω1 at a specific resonant frequency of the cantilever, to ensure sufficient sensitivity of the electrostatic force, a pair of ω1 and ω2 can be varied; this enables variable frequency measurements of ∂C/∂V by DEFM. The validity of the quantitation and spatial resolution of DEFM were assessed through the analysis of metal-oxide-silicon and Zn(O, S)/Cu(In,Ga)(Se,S)2 samples.

Accessory left gastric artery aneurysms in granulomatosis with polyangiitis: a case report and literature review.

Aneurysm formation is a potential complication of granulomatosis with polyangiitis (GPA), previously known as Wegener's granulomatosis. It is a very rare complication, but immediate diagnosis and therapy should be performed because an aneurysm can be life-threatening if it ruptures. An accessory left gastric artery (ALGA) is also a rare variant gastric artery that may obtain its blood supply from the left hepatic artery and left gastric artery. We herein describe a 57-year-old Japanese man who was diagnosed with GPA complicated by aneurysm rupture in an ALGA. Emergency surgery was performed after failure of arterial coil embolization to interrupt blood flow in the ALGA. The patient underwent partial resection of the lesser omentum, which contained all aneurysms. During partial resection of the lesser omentum, both the left gastric artery and ALGA were ligated because they were thought to be feeders of the aneurysms. Postoperative recovery was uneventful; no bleeding or recurrence of the aneurysms occurred. Immediate diagnosis and therapy should be performed for patients with GPA with symptoms of vascular ischemia or aortitis. Endovascular intervention is the first-choice therapy especially for hemodynamically stable patients with ruptured aneurysms or aneurysms located on variant arteries, which may have multiple blood supplies. In the present case, although endovascular treatment failed, the approach described herein was helpful during open surgery.

[A Case of Portal Vein Thrombosis Occurring during CapeOX and Bevacizumab Combination Therapy for Liver Metastasis].

A73 -year-old man underwent a sigmoidectomy for sigmoid colon cancer with liver metastasis. After the operation, he received CapeOX combined with bevacizumab therapy. After 6 courses, the liver metastasis was undetectable on computed tomography scans. After 15 courses, computed tomography revealed ascites, and chemotherapy was discontinued. Two months later, computed tomography revealed portal vein thrombosis. Owing to the chronic nature of the thrombosis, thrombolytic therapy was not initiated. However, preservation therapy using antiplatelet drugs for 1 month resolved the ascites and the thrombosis. The risk of serious thrombosis must be considered when using bevacizumab.

Improvement of KFM performance by intermittent bias application method and by sampling detection of cantilever deflection.

We have proposed an intermittent bias application method as well as a sampling detection method of cantilever deflection in Kelvin probe force microscopy (KFM) to improve its performances for surface potential measurements. In the former method, spiky biases, instead of the bias in a sinusoidal waveform normally used in KFM, are intermittently applied to generate electrostatic force at exact moments when the tip approaches the closest position to a sample surface. The latter one, on the other hand, realizes very sensitive detection of the electrostatic force, which is preferable in KFM. Both the dependence of the electrostatic force on the dc offset bias and the observed potential images clearly indicate that these two methods are very effective to improve the KFM performance.

Prostaglandin E1 prevents liver failure after excessive hepatectomy in the rat by up-regulating Cyclin C, Cyclin D1, and Bclxl.

Prostaglandin E1 (PGE1) has wide-ranging effects on cytoprotection and may play a role in preventing liver failure following excessive hepatectomy. We examined the effect of PGE1 on hepatocyte apoptosis and liver regeneration after 95% hepatectomy in a rat model. PGE1 or vehicle was intravenously administered 30 minutes before and during hepatectomy. The extent of hepatocyte injury was evaluated by serum alanine aminotransferase and aspartate aminotransferase levels. To evaluate hepatocyte apoptosis and liver regeneration, terminal deoxynucleotidyl transferase dUTP nick end labeling staining and Ki67 labeling were performed. The expression levels of Bcl-xL, Bcl-2, Bax, Cyclin C, Cyclin D1, Cyclin E, p21, transforming growth factor-beta, plasminogen activator inhibitor-1, and glyceraldehyde-2-phosphate dehydrogenase mRNA were also examined by reverse transcription-polymerase chain reaction. Survival was improved in the PGE1 group (26.6%), whereas all rats in the vehicle group died within 60 hours. PGE1 significantly suppressed the release of alanine aminotransferase and aspartate aminotransferase at 12 hours postoperatively. Pretreatment with PGE1 significantly increased the Ki67-positive cell count and decreased the terminal deoxynucleotidyl transferase dUTP nick end labeling positive cell count after hepatectomy, and also significantly increased the expression levels of Bcl-xL, Cyclin C, and Cyclin D1. Our results suggest that pretreatment with PGE1 may increase survival following hepatectomy by salvaging the remaining liver tissue, which it does by inhibiting apoptosis and stimulating hepatocyte proliferation.

Transfection of NF-kappaB decoy oligodeoxynucleotides into macrophages reduces murine fatal liver failure after excessive hepatectomy.

BACKGROUND: Macrophages play an important role in the initiation of hypercytokinemia, which is involved in the development of liver failure after excessive hepatectomy. This study was aimed at evaluating whether the selective suppression of nuclear factor kappa B (NF-kappaB) in macrophages by decoy oligodeoxynucleotides (ODN) could prevent liver failure after excessive hepatectomy. MATERIALS AND METHODS: Ninety percent hepatectomy was performed in 8-wk-old mice. NF-kappaB/decoy/ODN was transfected into the liver by the hemagglutinating virus of Japan-liposome method. The survival rate, serum levels of interleukin (IL)-1beta IL-6, and tumor necrosis factor-alpha, and the histological findings in the remnant liver were compared between the 90%-hepatectomized mice transfected with the decoy ODN (decoy group) and the 90%-hepatectomized mice injected with saline (control group). RESULT: The control group mice died within 48 h of the operation, while the survival rate in the decoy group at 48 h after the operation was 35%, and at 2 wk, 15%. The serum levels of all cytokines were significantly lower in the decoy group than in the control group. The number of terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling-positive cells in the remnant liver was smaller in the decoy group. CONCLUSION: Transfection of NF-kappaB/decoy/ODN reduces fatal liver failure in mice after excessive hepatectomy by suppressing hypercytokinemia, but offers only a low rate of survival.

Role of nitric oxide synthesized by nitric oxide synthase 2 in liver regeneration.

BACKGROUND/AIMS: Nitric oxide synthase 2 (NOS2) is expressed during liver regeneration after a partial hepatectomy (PHx); NOS2 subsequently synthesizes nitric oxide (NO). However, the role of NOS2-synthesized NO in post-PHx liver regeneration remains unclear. We investigated the role of NOS2-synthesized NO in liver regeneration. METHODS: NOS2 knockout (NOS2-KO) mice and control mice were subjected to PHx. Liver mass recovery and serum alanine aminotransferase (ALT) levels were then evaluated. The expressions of Ki-67 and single-strand DNA were also evaluated in remnant liver specimens. Differences in the gene expression profiles of the two groups of remnant liver specimens were analysed using a microarray and were validated using a reverse transcription-polymerase chain reaction (RT-PCR). RESULTS: In NOS2-KO mice, liver regeneration was delayed and apoptosis and serum ALT levels were higher than the levels in the control mice. A microarray study and RT-PCR revealed that heat shock protein 70 family (HSP70 family), haeme oxygenase 1 (Hmox1), neuropilin 1 (Nrp1) and epidermal growth factor receptor (EGFR) were downregulated in NOS2-KO mice. CONCLUSIONS: NOS2-synthesized NO may improve hepatocyte viability through the induction of the HSP70 family and Hmox1 and may sensitize the remnant liver to growth factors through the induction of Nrp1 and EGFR post-PHx.

Prostaglandin E1 improves survival rate after 95% hepatectomy in rats.

BACKGROUND/AIM: Prostaglandin E1 (PGE1) has a wide-ranging effect on cytoprotection. Overproduction of heat shock protein 70 (HSP70) in the liver protects hepatocytes under various pathologic conditions. In this study, we examined the effect of a nontoxic HSP-inducer, PGE1, on acute liver failure after 95% hepatectomy in rats. METHODS: PGE1 or vehicle was intravenously administered to rats 30 min before and during hepatectomy. RESULTS: Nine of 30 rats pretreated with PGE1 survived, whereas all 20 rats pretreated with vehicle died within 96 h after operation. During the 24-h postoperative period, PGE1 significantly suppressed the release of alanine aminotransferase and elevation of hyaluronic acid. Histological examination showed that the vacuolized hepatocytes and round hepatocytes with pyknotic nuclei are frequently seen in rats pretreated with vehicle, whereas active regeneration is seen in rats pretreated with PGE1. During the first 24 h after surgery, HSP70 induction was absent in the residual livers of vehicle-treated rats. In contrast, PGE1 stimulated the HSP accumulation within 24 h, and viable hepatocytes contained abundant HSP70 in their nuclei. CONCLUSION: Our results suggest that PGE1 may prevent acute liver failure after massive hepatectomy, at least in part, by enhancing HSP70 production in the residual liver.

Usefulness of absorbable sutures in preventing surgical site infection in hepatectomy.

We evaluated the usefulness of synthetic absorbable sutures (Vicryl) in preventing surgical site infection (SSI) after hepatectomy. A rat model of 60% partial hepatectomy was used. Bleeding from the cut surface of the liver was controlled by using two suture types: silk and Vicryl. In the Vicryl group, the lesser omentum was slightly adherent to the cut surface of the liver, while in the silk group, the suture remained, and severe adhesions were found. The number of Staphylococcus aureus was significantly larger in the silk group. We compared a group of patients (n = 125) who underwent hepatectomy using silk with one (n = 188) using Vicryl. The respective incidences of SSI and infection on the cut surface of the liver in the Vicryl group (3.2, 1.6%) were significantly lower than in the silk group (11.2, 8.8%). In accordance with the results of multivariate analysis, duration of operation, use of silk sutures and the complication of bile leakage were selected as independent factors. The risk of SSI in the silk group was 3.4 times that in the Vicryl group. The use of synthetic absorbable sutures, instead of silk sutures, in all the procedures of hepatectomy contributed significantly to the prevention of SSI.

PAI-1 plays an important role in liver failure after excessive hepatectomy in the rat.

BACKGROUND/AIMS: Well-organized turnover of the extracellular matrix is important in liver regeneration, which is regulated by the plasminogen activating system. The aim of this study was to investigate the role of plasminogen activator inhibitor-1 (PAI-1) after excessive hepatectomy and to ascertain whether angiotensin-converting enzyme (ACE) inhibitors, which are PAI-1 inhibitors as well, successfully improve the survival rate of rats that have undergone 95% partial hepatectomy (PHx). METHODS: Using liver tissues sampled after 90% or 95% PHx, the expression of PAI-1 mRNA was evaluated using reverse transcription polymerase chain reaction. Hepatic PAI-1 protein and urokinase-type plasminogen activator (uPA) levels were determined by enzyme-linked immunosorbent assay. Survival study and cytodynamic analysis by 5-bromo-2'-deoxyuridine staining were performed to evaluate the effects of ACE inhibition. RESULTS: The levels of PAI-1 mRNA and hepatic PAI-1 protein in the 95% PHx group peaked and were then maintained. By contrast, the uPA level fell relative to the 90% PHx group. Additionally, the hepatic PAI-1 protein level decreased and the survival rate improved in the 95% PHx rats that had undergone ACE inhibition. CONCLUSIONS: Our experimental results suggest that PAI-1 plays a role in the occurrence of liver failure after excessive hepatectomy via accelerated maturation of pro-uPA and fibrinolytic factors. These are potential molecular therapeutic targets for liver failure after excessive hepatectomy.

Tip-to-sample distance dependence of an electrostatic force in KFM measurements.

In most scanning probe methods like an atomic force microscopy, a cantilever is mechanically vibrated in order to obtain topographies. Therefore, a tip-to-sample distance periodically changes during the scanning. Since the electrostatic force, which is a long-range force, is used for potential feedback in Kelvin probe force microscopy (KFM), such mechanical vibration leads to the fluctuation of the electrostatic force between the tip and the sample. In this study, firstly, we performed two-dimensional simulations of the electric fields between surfaces of the tip and the sample and evaluated the tip-to-sample distance dependence of the electrostatic force. Secondly, we experimentally confirmed the existence of the fluctuation of the electrostatic force and the tip-to-sample distance dependence of the electrostatic force was evaluated. Both the simulations and the experiments on the tip-to-sample distance dependence showed the importance of considering the tip sidewall effect in the KFM potential determination.

Magnetic field detection for current evaluation by magnetic force microscopy.

A current measurement method through magnetic field detection by magnetic force microscopy was proposed and demonstrated. We observed the magnetic field induced by an AC below 2.2 microA around a GaAs/AlGaAs mesa stripe. To achieve high sensitivity in magnetic field detection, we tuned the AC bias frequency to the torsional resonant frequency of the cantilever. As a result, the sensitivity of the magnetic field detection was much improved and specific features of the magnetic field around the mesa stripe were clearly observed at a current in sub-microA range.

Light-illuminated STM studies on photo-absorption in InAs nanowires.

We fabricated surface InAs nanowires along GaAs giant step structures on GaAs (110) vicinal substrates, and their photo-absorption properties were studied by scanning tunneling microscopy (STM) under light illumination. In photo-induced current detection, it was difficult to identify the photo-absorption signals in the InAs nanowires because of the electrical isolation of the surface nanostructures from the conductive substrate. On the other hand, optical response measurements of differential conductance under small AC bias modulation in STM enabled us to obtain the photo-absorption signals from the surface nanostructures with avoiding such an electrical isolation problem. We successfully observed optical response images of differential conductance with a clear contrast between InAs nanowires and surrounding GaAs region by the appropriate tuning of the illuminating photon energy to excite the InAs nanowires selectively.

Current and potential characterization on InAs nanowires by contact-mode atomic force microscopy and Kelvin probe force microscopy.

We fabricated InAs nanowires on GaAs giant step structures, and studied their surfaces by two methods; one was current detection by contact-mode atomic force microscopy, and the other was surface potential measurement by Kelvin probe force microscopy (KFM). In the current detection method, the regions where the large current flowed were distributed along the step edges, and these regions agreed well with the expected distribution of InAs. This result confirms that the InAs nanowires were formed along the GaAs giant step edges. The KFM measurements showed that the potential value became more negative along each step edge, where the InAs nanowire was expected to be formed. The surface potential of the InAs nanowires is more negative than that of the surrounding GaAs, which may result from the electron accumulation in the InAs nanowires.