Universal Map of Gas-Dependent Kinetic Selectivity in Carbon Nanotube Growth.

Single-walled carbon nanotubes have been a candidate for outperforming silicon in ultrascaled transistors, but the realization of nanotube-based integrated circuits requires dense arrays of purely semiconducting species. In order to directly grow such nanotube arrays on wafers, control over kinetics and thermodynamics in tube-catalyst systems plays a key role, and further progress requires a comprehensive understanding of seemingly contradictory reports on the growth kinetics. Here, we propose a universal kinetic model that decomposes the growth rates of nanotubes into the adsorption and removal of carbon atoms on the catalysts, and we provide its quantitative verification by ethanol-based isotope labeling experiments. While the removal of carbon from catalysts dominates the growth kinetics under a low supply of precursors, resulting in chirality-independent growth rates, our kinetic model and experiments demonstrate that chiral angle-dependent growth rates emerge when sufficient amounts of carbon and etching agents are cosupplied. The kinetic maps, as a product of generalizing the model, include five types of kinetic selectivity that emerge depending on the absolute quantities of gases with opposing effects. Our findings not only resolve discrepancies existing in the literature but also offer rational strategies to control the chirality, length, and density of nanotube arrays for practical applications.

Primary leiomyoma of the ureter: a case report.

BACKGROUND: Only 14 cases of leiomyoma with ureteral origin have been reported previously. Such primary leiomyomas often present as hydronephrosis, making the diagnosis difficult. Radical nephroureterectomy is often performed because of the possible diagnosis of a malignant tumor. We report the 15th case of primary leiomyoma with a ureteral origin. CASE PRESENTATION: A 51-year-old Japanese man presented with a chief complaint of asymptomatic gross hematuria with a history of hypertension. Enhanced computed tomography showed a tumor at the upper part of the right ureter that appeared to be the cause of hydronephrosis and contracted kidney; no retroperitoneal lymphadenopathy and distal metastasis were observed. A well-defined 20-mm (diameter) defect was identified at the upper of the right ureter on retrograde pyelogram with no bladder cancer on cystoscopy. Urine cytology and right divided renal urine cytology findings were negative. Laparoscopic nephroureterectomy was performed, and the extracted tumor measured 20 × 13 mm. Histopathological examination revealed primary leiomyoma with no recurrence 16 months after the operation. CONCLUSIONS: Preoperative examination with the latest available ureteroscopic technology can help preserve renal function in the case of benign tumors by enabling preoperative ureteroscopic biopsy or intraoperative rapid resection. Moreover, nephroureterectomy is recommended in the case of preoperative suspicion of ureteral malignant tumors.

A case of familial Mediterranean fever associated with compound heterozygosity for the pyrin variant L110P-E148Q/M680I in Japan.

Familial Mediterranean fever (FMF) is an autosomal recessive disorder characterized by recurrent and self-limited fever attacks and serositis/arthritis. The M694V, M694I, M680I, V726A, and E148Q mutations in MEFV, the gene responsible for FMF, account for most FMF cases in Mediterranean populations. In Japan, M694I and E148Q are most frequently detected; M694V, M680I, and V726A have not been identified so far. We report the first case of FMF associated with M680I in Japan.