Electrical manipulation of a topological antiferromagnetic state.

Electrical manipulation of phenomena generated by nontrivial band topology is essential for the development of next-generation technology using topological protection. A Weyl semimetal is a three-dimensional gapless system that hosts Weyl fermions as low-energy quasiparticles1-4. It has various exotic properties, such as a large anomalous Hall effect (AHE) and chiral anomaly, which are robust owing to the topologically protected Weyl nodes1-16. To manipulate such phenomena, a magnetic version of Weyl semimetals would be useful for controlling the locations of Weyl nodes in the Brillouin zone. Moreover, electrical manipulation of antiferromagnetic Weyl metals would facilitate the use of antiferromagnetic spintronics to realize high-density devices with ultrafast operation17,18. However, electrical control of a Weyl metal has not yet been reported. Here we demonstrate the electrical switching of a topological antiferromagnetic state and its detection by the AHE at room temperature in a polycrystalline thin film19 of the antiferromagnetic Weyl metal Mn3Sn9,10,12,20, which exhibits zero-field AHE. Using bilayer devices composed of Mn3Sn and nonmagnetic metals, we find that an electrical current density of about 1010 to 1011 amperes per square metre induces magnetic switching in the nonmagnetic metals, with a large change in Hall voltage. In addition, the current polarity along the bias field and the sign of the spin Hall angle of the nonmagnetic metals-positive for Pt (ref. 21), close to 0 for Cu and negative for W (ref. 22)-determines the sign of the Hall voltage. Notably, the electrical switching in the antiferromagnet is achieved with the same protocol as that used for ferromagnetic metals23,24. Our results may lead to further scientific and technological advances in topological magnetism and antiferromagnetic spintronics.

Author Correction: Iron-based binary ferromagnets for transverse thermoelectric conversion.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Iron-based binary ferromagnets for transverse thermoelectric conversion.

Thermoelectric generation using the anomalous Nernst effect (ANE) has great potential for application in energy harvesting technology because the transverse geometry of the Nernst effect should enable efficient, large-area and flexible coverage of a heat source. For such applications to be viable, substantial improvements will be necessary not only for their performance but also for the associated material costs, safety and stability. In terms of the electronic structure, the anomalous Nernst effect (ANE) originates from the Berry curvature of the conduction electrons near the Fermi energy1,2. To design a large Berry curvature, several approaches have been considered using nodal points and lines in momentum space3-10. Here we perform a high-throughput computational search and find that 25 percent doping of aluminium and gallium in alpha iron, a naturally abundant and low-cost element, dramatically enhances the ANE by a factor of more than ten, reaching about 4 and 6 microvolts per kelvin at room temperature, respectively, close to the highest value reported so far. The comparison between experiment and theory indicates that the Fermi energy tuning to the nodal web-a flat band structure made of interconnected nodal lines-is the key for the strong enhancement in the transverse thermoelectric coefficient, reaching a value of about 5 amperes per kelvin per metre with a logarithmic temperature dependence. We have also succeeded in fabricating thin films that exhibit a large ANE at zero field, which could be suitable for designing low-cost, flexible microelectronic thermoelectric generators11-13.

Endoscopic treatment of bile duct stones with benign choledochojejunal anastomotic stenosis.

[BACKGROUND AND AIMS]: Endoscopic interventions for bile duct stones (BDS) with benign choledochojejunal anastomotic stenosis (bCJS) are challenging. Therefore, we investigated endoscopic interventions for BDS with bCJS. [METHODS]: Seventeen patients with BDS with bCJS were retrospectively analyzed. Patient characteristics, technical success, adverse events (AEs), and recurrence were evaluated. [RESULTS]: In 17 patients, the median diameters of the bile duct and BDS were both 8 mm. The median number of BDS was 3. The technical success rate was 94% (16/17). Ten patients underwent balloon dilation at the choledochojejunal anastomotic site (CAS), the median diameter of balloon dilation was 10.5 mm, and waist disappearance was achieved in 2. Six patients had fully covered self-expandable metal stents (FCSEMS) with a diameter of 10 mm placed at the CAS. BDS were removed after balloon dilation or FCSEMS removal, and 6 out of 16 patients were treated with a combination of lithotripsy and 5 with peroral direct cholangioscopy (PDCS). Regarding AEs, perforation at the CAS by balloon dilation occurred in 1 patient. The median follow-up was 3701 days. Nine out of 16 patients (56%) had recurrence. The patients treated with combination of PDCS at BDS removal (p=0.022) and waist disappearance at the CAS by balloon dilation (p=0.035) had significantly fewer recurrences. [CONCLUSIONS]: Endoscopic interventions for BDS with bCJS are useful and relatively safe; however, long-term follow-ups showed frequent recurrences. Recurrence was common in patients not treated with the combination of PDCS at BDS removal and those without waist disappearance at the CAS by balloon dilation.

Bipolar-current needle-knife with a water jet function (Jet B-knife) shortens the procedure time of endoscopic submucosal dissection for colorectal tumors.

BACKGROUND: Endoscopic submucosal dissection (ESD) is a technically difficult and time-consuming procedure for the treatment of large colorectal tumors. In Japan, the ball-tip bipolar-current needle-knife (BB-knife) has been used in ESD as a safe device that minimizes the damage to deeper tissues of colorectal neoplasms. In May 2012, a BB-knife combined with a water jet function (Jet B-knife) was newly developed. METHODS: This retrospective study was aimed at examining the effectiveness and safety of the Jet B-knife. The BB-knife was used in 276 lesions (BB-knife group), while the Jet B-knife was used in 245 lesions (Jet B-knife group). We evaluated tumor characteristics and the results of the ESD procedures, including the size of the resected tumor, histological diagnosis, time required for resection, frequency of using other electrical devices, en bloc resection rate, and incidence rate of associated complications. Then, the data obtained were compared between the two groups. RESULTS: The histological evaluation of the resected tumors revealed that the incidence of cancer was not significantly different between the two groups. The median time required for resection was 103 min (45-255) in the BB-knife group and 51 min (28-210) in the Jet B-knife group. The difference was statistically significant (p < 0.05). Furthermore, the median tumor diameters were 23.1 mm (18-50) and 26.2 mm (20-60) in the BB-knife and Jet B-knife groups, respectively, demonstrating a statistically significant difference (p < 0.05). Multivariate logistic regression analysis revealed that short resection time (p < 0.001) and reduced use of hemostatic devices (p < 0.01) were independent favorable features of Jet B-knife. The en bloc resection rate and the perforation rate were not statistically significant between the two groups. CONCLUSIONS: Use of the Jet B-knife may contribute to the development of a time-saving, cost-effective, and safe procedure for ESD of colorectal tumors.

[A case of pancreatic actinomycosis diagnosed by EUS-FNA].

A 60-year-old male patient had alcoholic chronic pancreatitis. Three months prior, he had undergone an exchange of pancreatic duct stents. In December 201X-1, magnetic resonance imaging and computed tomography (CT) scan results showed a caput pancreatic mass and common bile duct dilatation. We considered that it was because of chronic pancreatitis and decided to follow up by imaging studies. Further, in March 201X, a CT scan result revealed worsening of the mass and bile duct dilation. We assessed the mass by endoscopic ultrasound and fine-needle aspiration. Histological findings revealed to an interstitial tissue infiltrated by several neutrophils and plasma cells and abscess-forming inflammation like sulfur granule. The mass was improved by antibiotic administration for 6 months.

Usefulness of endoscopic metal stent placement for malignant afferent loop obstruction.

BACKGROUND: Malignant afferent loop obstruction (mALO) can cause cholangitis, pancreatitis, and perforation due to blind loop dilatation. However, peritoneal dissemination, lymph node metastasis, and recurrence of the tumor are the main causes of mALO, and most cases are in the advanced stage with thoracicoabdominal fluid retention, for which surgery and percutaneous transhepatic treatment are challenging. At our hospital, endoscopic metal stent placement (EMSP) has been applied for such mALO. We retrospectively investigated the usefulness of EMSP for mALO. METHODS: We conducted a retrospective analysis of 11 mALO patients with EMSP between January 2008 and December 2018. The following items were evaluated: the characteristics of patients, technical success and adverse events of EMSP, clinical efficacy, and outcome after EMSP. RESULTS: The surgical procedures and reconstruction methods were distal gastrectomy with Billroth II reconstruction for 3 patients, pancreaticoduodenectomy with modified-Child reconstruction for 7, choledochojejunostomy with Roux-en-Y reconstruction for 1. The cause of mALO was peritoneal dissemination for 6 patients, local recurrence for 3, lymph node metastasis for 1, and afferent loop invasion for 1. EMSP was attempted in 13 sessions for 11 patients, and successful in 12 of 13 sessions. There were no adverse events. The clinical efficacy was high in successful EMSP. The median survival time after EMSP was 118 days. Ten patients died of primary disease and one patient died of uncontrollable cholangitis after the failure of EMSP. mALO recurred and EMSP was repeated for 2 of 10 patients who died of primary disease. CONCLUSIONS: The success rate of EMSP for mALO was high in patients with poor general conditions due to advanced-stage malignant tumors and it was able to be safely performed, suggesting its high clinical efficacy. The incidence of mALO recurrence after EMSP was low.

Giant Anisotropic Magnetoresistance due to Purely Orbital Rearrangement in the Quadrupolar Heavy Fermion Superconductor PrV_{2}Al_{20}.

We report the discovery of giant and anisotropic magnetoresistance due to the orbital rearrangement in a non magnetic correlated metal. In particular, we measured the magnetoresistance under fields up to 31.4 T in the cubic Pr-based heavy fermion superconductor PrV_{2}Al_{20} with a non magnetic Γ_{3} doublet ground state, exhibiting antiferroquadrupole ordering below 0.7 K. For the [100] direction, we find that the high-field phase appears between 12 and 25 T, accompanied by a large jump at 12 T in the magnetoresistance (ΔMR∼100%) and in the anisotropic magnetoresistivity ratio by ∼20%. These observations indicate that the strong hybridization between the conduction electrons and anisotropic quadrupole moments leads to the Fermi surface reconstruction upon crossing the field-induced antiferroquadrupole (orbital) rearrangement.

Phase II clinical trial of second-line weekly paclitaxel plus trastuzumab for patients with HER2-positive metastatic gastric cancer.

BACKGROUND: Combination therapy with fluorouracil, platinum, and trastuzumab (Tmab) is the first-line treatment for human epidermal growth factor receptor 2 (HER2)-positive gastric cancer, and there is currently no established second-line therapy. We evaluated the efficacy and safety of weekly paclitaxel plus Tmab as second-line chemotherapy for HER2-positive gastric cancer patients. PATIENTS AND METHODS: Eligible patients were older than or equal to 20 years, had histologically confirmed gastric adenocarcinoma that was HER2 positive (immunohistochemistry 3+ or immunohistochemistry 2+ and fluorescence in-situ hybridization positive or dual color in-situ hybridization positive), and had been treated previously with chemotherapy (pretreated or not with Tmab). Patients received weekly paclitaxel plus Tmab as the second-line chemotherapy. The primary endpoint was the overall response rate (ORR; threshold ORR=20% and expected ORR=35%). RESULTS: Twenty-eight patients were enrolled. ORR was 21.4%. The median progression-free survival (PFS) was 4.6 months. The median overall survival (OS) was 9.6 months. No significant differences were observed in ORR, PFS, or OS between the Tmab beyond progression (TBP) group (n=20) and the non-TBP group (n=8). However, in the TBP group, a therapeutic effect was associated with the duration of PFS in the first-line Tmab treatment [≥6 months PFS in the first-line Tmab treatment (n=10) vs. <6 months (n=10); ORR: 40 and 10%, P=0.303, PFS: 6.2 and 2.8 months, P=0.005, OS: 15.8 and 6.5 months, P=0.006, respectively]. CONCLUSION: Weekly paclitaxel plus Tmab was not superior as second-line chemotherapy for HER2-positive gastric cancer patients, but may be effective for patients who showed better responses to Tmab-combined chemotherapy in the first-line treatment.

Treatment patterns and outcomes of unresectable pancreatic cancer patients in real-life practice: a region-wide analysis.

BACKGROUND: FOLFIRINOX (FFX) and gemcitabine (GEM) plus nab-paclitaxel (GnP) have recently been available for treating pancreatic ductal adenocarcinoma (PDAC). We investigated trends in characteristics, treatment and outcomes of unselected patients with unresectable PDAC in real-life practice in Japan. METHODS: We retrospectively reviewed the medical records of 1085 patients diagnosed as having unresectable or recurrent PDAC in multiple centers in the Hokuriku area between January 2009 and July 2015. RESULTS: The incidence of pathologically proven PDAC had increased from 18.7% in 2009 to 56.2% in 2015. Oncological therapy was administered to 779 patients (71.8%): chemotherapy (n = 675), chemo-radiotherapy (n = 92) or radiotherapy (n = 12); the remaining patients were treated with best supportive care. Of 100 patients diagnosed in 2009, 62.0% received GEM as first-line chemotherapy; whereas 30.7% of the 75 patients diagnosed in 2015 received FFX, 25.3% GnP, 22.7% GEM and 17.3% S-1. The objective response rates of patients treated with FFX, GnP and GEM were 14.9%, 35.0% and 5.5%, respectively and the OS 10.3, 9.9 and 7.5 months after FFX, GnP and GEM, respectively. Grade 3 or greater any hematological toxicity occurred in 70.2%, 70.0% and 18.8% of the patients treated with FFX, GnP and GEM, respectively. The reasons for treatment discontinuation were adverse events in 9.8%, 26.7% and 24.1% of the patients treated with FFX, GnP and GEM, respectively. CONCLUSION: Chemotherapeutic protocols changed dramatically between 2009 and 2015. Continuous collection and analysis for our cohort with longer follow-up provides useful information about treatment selection and prediction of outcome.

Hepatic interferon-stimulated genes are differentially regulated in the liver of chronic hepatitis C patients with different interleukin-28B genotypes.

UNLABELLED: Pretreatment up-regulation of hepatic interferon (IFN)-stimulated genes (ISGs) has a stronger association with the treatment-resistant interleukin (IL)28B minor genotype (MI; TG/GG at rs8099917) than with the treatment-sensitive IL28B major genotype (MA; TT at rs8099917). We compared the expression of ISGs in the liver and blood of 146 patients with chronic hepatitis C who received pegylated IFN and ribavirin combination therapy. Gene expression profiles in the liver and blood of 85 patients were analyzed using an Affymetrix GeneChip (Affymetrix, Santa Clara, CA). ISG expression was correlated between the liver and blood of the MA patients, whereas no correlation was observed in the MI patients. This loss of correlation was the result of the impaired infiltration of immune cells into the liver lobules of MI patients, as demonstrated by regional gene expression analysis in liver lobules and portal areas using laser capture microdissection and immunohistochemical staining. Despite having lower levels of immune cells, hepatic ISGs were up-regulated in the liver of MI patients and they were found to be regulated by multiple factors, namely, IL28A/B, IFN-λ4, and wingless-related MMTV integration site 5A (WNT5A). Interestingly, WNT5A induced the expression of ISGs, but also increased hepatitis C virus replication by inducing the expression of the stress granule protein, GTPase-activating protein (SH3 domain)-binding protein 1 (G3BP1), in the Huh-7 cell line. In the liver, the expression of WNT5A and its receptor, frizzled family receptor 5, was significantly correlated with G3BP1. CONCLUSIONS: Immune cells were lost and induced the expression of other inflammatory mediators, such as WNT5A, in the liver of IL28B minor genotype patients. This might be related to the high level of hepatic ISG expression in these patients and the treatment-resistant phenotype of the IL28B minor genotype.

MicroRNA-27a regulates lipid metabolism and inhibits hepatitis C virus replication in human hepatoma cells.

The replication and infectivity of the lipotropic hepatitis C virus (HCV) are regulated by cellular lipid status. Among differentially expressed microRNAs (miRNAs), we found that miR-27a was preferentially expressed in HCV-infected liver over hepatitis B virus (HBV)-infected liver. Gene expression profiling of Huh-7.5 cells showed that miR-27a regulates lipid metabolism by targeting the lipid synthetic transcription factor RXRα and the lipid transporter ATP-binding cassette subfamily A member 1. In addition, miR-27a repressed the expression of many lipid metabolism-related genes, including FASN, SREBP1, SREBP2, PPARα, and PPARγ, as well as ApoA1, ApoB100, and ApoE3, which are essential for the production of infectious viral particles. miR-27a repression increased the cellular lipid content, decreased the buoyant density of HCV particles from 1.13 to 1.08 g/cm(3), and increased viral replication and infectivity. miR-27a overexpression substantially decreased viral infectivity. Furthermore, miR-27a enhanced in vitro interferon (IFN) signaling, and patients who expressed high levels of miR-27a in the liver showed a more favorable response to pegylated IFN and ribavirin combination therapy. Interestingly, the expression of miR-27a was upregulated by HCV infection and lipid overload through the adipocyte differentiation transcription factor C/EBPα. In turn, upregulated miR-27a repressed HCV infection and lipid storage in cells. Thus, this negative feedback mechanism might contribute to the maintenance of a low viral load and would be beneficial to the virus by allowing it to escape host immune surveillance and establish a persistent chronic HCV infection.

Heavy-fermion superconductivity in the quadrupole ordered state of PrV2Al20.

PrV2Al20 is a rare example of a heavy-fermion system based on strong hybridization between conduction electrons and nonmagnetic quadrupolar moments of the cubic Γ3 ground doublet. Here, we report that a high-quality single crystal of PrV2Al20 exhibits superconductivity at Tc=50 mK in the antiferroquadrupole-ordered state under ambient pressure. The heavy-fermion character of the superconductivity is evident from the specific heat jump of ΔC/T∼0.3 J/mol K(2) and the effective mass m*/m0∼140 estimated from the temperature dependence of the upper critical field. Furthermore, the high-quality single crystals exhibit double transitions at TQ=0.75 K and T*=0.65 K associated with quadrupole and octupole degrees of freedom of the Γ3 doublet. In the ordered state, the specific heat C/T shows a T(3) dependence, indicating the gapless mode associated with the quadrupole order, the octupole order, or both. The strong sensitivity to impurity of the superconductivity suggests unconventional character due to significant quadrupolar fluctuations.

Peretinoin, an acyclic retinoid, improves the hepatic gene signature of chronic hepatitis C following curative therapy of hepatocellular carcinoma.

BACKGROUND: The acyclic retinoid, peretinoin, has been shown to be effective for suppressing hepatocellular carcinoma (HCC) recurrence after definitive treatment in a small-scale randomized clinical trial. However, little has been documented about the mechanism by which peretinoin exerts its inhibitory effects against recurrent HCC in humans in vivo. METHODS: Twelve hepatitis C virus-positive patients whose HCC had been eradicated through curative resection or ablation underwent liver biopsy at baseline and week 8 of treatment with either a daily dose of 300 or 600 mg peretinoin. RNA isolated from biopsy samples was subjected to gene expression profile analysis. RESULTS: Peretinoin treatment elevated the expression levels of IGFBP6, RBP1, PRB4, CEBPA, G0S2, TGM2, GPRC5A, CYP26B1, and many other retinoid target genes. Elevated expression was also observed for interferon-, Wnt-, and tumor suppressor-related genes. By contrast, decreased expression levels were found for mTOR- and tumor progression-related genes. Interestingly, gene expression profiles for week 8 of peretinoin treatment could be classified into two groups of recurrence and non-recurrence with a prediction accuracy rate of 79.6% (P<0.05). In the liver of patients with non-recurrence, expression of PDGFC and other angiogenesis genes, cancer stem cell marker genes, and genes related to tumor progression was down-regulated, while expression of genes related to hepatocyte differentiation, tumor suppression genes, and other genes related to apoptosis induction was up-regulated. CONCLUSIONS: Gene expression profiling at week 8 of peretinoin treatment could successfully predict HCC recurrence within 2 years. This study is the first to show the effect of peretinoin in suppressing HCC recurrence in vivo based on gene expression profiles and provides a molecular basis for understanding the efficacy of peretinoin.

Malnutrition impairs interferon signaling through mTOR and FoxO pathways in patients with chronic hepatitis C.

BACKGROUND & AIMS: Patients with advanced chronic hepatitis C (CH-C) often are malnourished, but the effects of malnutrition on interferon (IFN) signaling and response to treatment have not been determined. We assessed the importance of the nutritional state of the liver on IFN signaling and treatment response. METHODS: We studied data from 168 patients with CH-C who were treated with the combination of pegylated-IFN and ribavirin. Plasma concentrations of amino acids were measured by mass spectrometry. Liver gene expression profiles were obtained from 91 patients. Huh-7 cells were used to evaluate the IFN signaling pathway, mammalian target of rapamycin complex 1 (mTORC1), and forkhead box O (FoxO). Antiviral signaling induced by branched-chain amino acids (BCAAs) was determined using the in vitro hepatitis C virus replication system. RESULTS: Multivariate logistic regression analysis showed that Fischer's ratio was associated significantly with nonresponders, independent of interleukin-28B polymorphisms or the histologic stage of the liver. Fischer's ratio was correlated inversely with the expression of BCAA transaminase 1, and was affected by hepatic mTORC1 signaling. IFN stimulation was impaired substantially in Huh-7 cells grown in medium that was low in amino acid concentration, through repressed mTORC1 signaling, and increased Socs3 expression, which was regulated by Foxo3a. BCAA could restore impaired IFN signaling and inhibit hepatitis C virus replication under conditions of malnutrition. CONCLUSIONS: Malnutrition impaired IFN signaling by inhibiting mTORC1 and activating Socs3 signaling through Foxo3a. Increasing BCAAs to up-regulate IFN signaling might be used as a new therapeutic approach for patients with advanced CH-C.