Edge-sensitive Semiconducting Behaviour in Low-defect Narrow Graphene Nanoribbons

Low-defect graphene nanoribbons (GNRs) derived from the unzipping of carbon nanotubes have exhibited large energy band gaps (transport gaps), despite having widths in the order of ∼100 nm. Here, we report on the unique semiconducting behaviour of very narrow, low-defect GNRs, with widths of less than 20 nm. Narrow GNRs are highly resistive, and additional annealing is required to reduce their resistivity. The GNRs display ambipolar rather than evident semiconducting behaviour (p- and n-types), exhibiting normalized Ion/Ioff as great as ∼106 (close to those in a few nm-order-width GNRs) and which are very sensitive to the atmosphere and the termination of the GNRs’ edges by foreign atoms (hydrogen for n-type and oxygen for p-type). It is also revealed that the activation energy (Ea ∼35 meV) estimated from the temperature dependence of the minimum conductance is smaller than those in ∼100 nm width GNRs. The observed sharp conductance peak on back-gate voltage (Vbg) dependence and its strong correlation with the Ea value suggest the presence of possible resonant tunnelling through shallow impurity levels with the small Ea introduced by the edge terminations by foreign atoms, which provides the observed unique behaviour, including the high Ion/Ioff. An energy band gap as large as ∼215 meV is also confirmed from the Ioff voltage region on Vbg. These narrow GNRs must open the door to large-scale graphene integration circuits based on CMOS-like behaviour

Altered oscillation of Doppler-derived renal and renal interlobar venous flow velocities in hypertensive and diabetic patients

Background and purpose Flow velocity oscillation rate (FVOR) of the renal interlobar vein has been reported to be decreased in patients with urinary obstruction or diabetic nephropathy, and increased in those with hypertension during pregnancy. To clarify the clinical role of the renal interlobar venous FVOR, we investigated the flow velocity patterns of the renal vessels in patients with hypertension (HT) and/or diabetes (DM). Methods and results Pulsed-wave Doppler sonography was performed in 34 patients: 15 with HT, 10 with DM, and nine with both HT and DM (HT-DM). Each FVOR of the right and left interlobar veins was closely and positively correlated with the ipsilateral interlobar arterial resistive index (RI), especially in the HT group, but not with the estimated glomerular filtration rate. The right interlobar venous FVOR was decreased in the DM and HT-DM groups compared to the HT group. Conclusion The renal interlobar venous FVOR is strongly influenced by the arterial RI in HT patients, and is reduced in DM patients without an obvious relationship with diabetic nephropathy. These findings should be noted for the clinical application of renal interlobar venous flow analysis

Characteristic systolic waveform of left ventricular longitudinal strain rate in patients with hypertrophic cardiomyopathy

We analyzed the waveform of systolic strain and strain-rate curves to find a characteristic left ventricular (LV) myocardial contraction pattern in patients with hypertrophic cardiomyopathy (HCM), and evaluated the utility of these parameters for the differentiation of HCM and LV hypertrophy secondary to hypertension (HT). From global strain and strain-rate curves in the longitudinal and circumferential directions, the time from mitral valve closure to the peak strains (T-LS and T-CS, respectively) and the peak systolic strain rates (T-LSSR and T-CSSR, respectively) were measured in 34 patients with HCM, 30 patients with HT, and 25 control subjects. The systolic strain-rate waveform was classified into 3 patterns ("V", "W", and "√" pattern). In the HCM group, T-LS was prolonged, but T-LSSR was shortened; consequently, T-LSSR/T-LS ratio was distinctly lower than in the HT and control groups. The "√" pattern of longitudinal strain-rate waveform was more frequently seen in the HCM group (74 %) than in the control (4 %) and HT (20 %) groups. Similar but less distinct results were obtained in the circumferential direction. To differentiate HCM from HT, the sensitivity and specificity of the T-LSSR/T-LS ratio <0.34 and the "√"-shaped longitudinal strain-rate waveform were 85 and 63 %, and 74 and 80 %, respectively. In conclusion, in patients with HCM, a reduced T-LSSR/T-LS ratio and a characteristic "√"-shaped waveform of LV systolic strain rate was seen, especially in the longitudinal direction. The timing and waveform analyses of systolic strain rate may be useful to distinguish between HCM and HT

Simeprevir-Based Triple Therapy with Reduced Doses of Pegylated Interferon α-2a Plus Ribavirin for Interferon Ineligible Patients with Genotype 1b Hepatitis C Virus

Background/AimsThe present study aimed to evaluate the safety and efficacy of simeprevir-based triple therapy with reduced doses of pegylated interferon (PEG-IFN) and ribavirin for interferon (IFN) ineligible patients, such as elderly and/or cirrhotic patients, and to elucidate the factors contributing to a sustained virologic response (SVR).Methods : One hundred IFN ineligible patients infected with genotype 1b hepatitis C virus (HCV) were treated. Simeprevir (100 mg) was given orally together with reduced doses of PEG-IFN-α 2a (90 μg), and ribavirin (200 mg less than the recommended dose).Results : The patients’ median age was 70 years, and 70 patients were cirrhotic. Three patients (3%) discontinued treatment due to adverse events. The SVR rate was 64%. Factors that significantly contributed to the SVR included the γ-glutamyl transferase and α-fetoprotein levels, interleukin-28B (IL28B) polymorphism status, and the level and reduction of HCV RNA at weeks 2 and 4. The multivariate analysis showed that the IL28B polymorphism status was the only independent factor that predicted the SVR, with a positive predictive value of 77%.Conclusion : sSimeprevir-based triple therapy with reduced doses of PEG-IFN and ribavirin was safe and effective for IFN ineligible patients infected with genotype 1b HCV. IL28B polymorphism status was a useful predictor of the SVR

The Real-World Safety and Efficacy of Daclatasvir and Asunaprevir for Elderly Patients

Background/AimsAlthough daclatasvir with asunaprevir was approved in Japan for interferon ineligible or intolerant patients, patients aged ≥75 years were excluded in the phase III trial. The present study aimed to evaluate the safety and efficacy of this therapy for elderly patients aged ≥75 years and to clarify whether an extremely high sustained virological response (SVR) rate can be achieved, even in a real-world setting when patients with resistance-associated substitutions (RASs) to nonstructural protein 5A (NS5A) inhibitors or prior simeprevir failure are excluded.Methods : Daclatasvir (60 mg) and asunaprevir (100 mg) were orally administered daily for 24 weeks. Patients without pre-existing NS5A RASs and simeprevir failure were enrolled in this study.Results : Overall, 110 patients were treated. The median age was 73 years old. The SVR rates of total patients, those aged ≥75 years, and those aged <75 years were 97% (107/110), 98% (46/47), and 97% (61/63), respectively. The treatment of two patients (2%) was discontinued because of adverse events.Conclusion : sDaclatasvir with asunaprevir was a safe treatment, even in patients aged ≥75 years. When patients without pre-existing NS5A RASs and prior simeprevir failure were selected, an extremely high SVR rate could be achieved irrespective of age

Petit-spot volcanoes on the oldest portion of the Pacific plate

The formation of a petit-spot volcano involves the ascent of an asthenospheric melt to the outboard part of a plate subduction zone where flexure of the plate has taken place in the outer trench swell. On the Pacific Plate, the only previously known examples of such volcanoes were in the vicinity of the Japan Trench. We describe here a newly discovered petit-spot submarine volcano that formed in one of the oldest parts of the Pacific Plate among a cluster of small conical knolls to the southeast of Minamitorishima (Marcus) Island. Geochronological data indicate that this petit-spot volcanic eruption occurred less than 3 million years ago. The volcano erupted on the eastern slope of the outer rise, and it is at an unusually large distance from the Mariana trench axis (~800 km) because this rise, near the older part of the Pacific Plate, is wider than those of other subduction systems