Thermal defect healing of single-walled carbon nanotubes assisted by supplying carbon-containing reactants

We experimentally investigated the effect of carbon-containing reactants (C2H2) on healing the defects in single-walled carbon nanotubes (SWCNTs) by thermal processes at high temperatures (∼1100 °C). Introducing C2H2 notably improved the crystallinity of healed SWCNTs compared with the thermal process in Ar ambient without C2H2. The defect healing rate increased with increasing C2H2 partial pressure, and the healing effect of C2H2 was more remarkable for relatively thinner SWCNTs (<1.1 nm). Combined with the relevant theoretical work reported previously, we propose a healing model in which C2H2 helps to heal the vacancy defects and increases the healing rate at high temperatures.This is the version of the article before peer review or editing, as submitted by an author to Applied Physics Express. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The Version of Record is available online at https://doi.org/10.35848/1882-0786/acaaec

Inter-impurity and impurity-host magnetic correlations in semiconductors with low-density transition-metal impurities

Experiments on (Ga,Mn)As in the low-doping insulating phase have shown evidence for the presence of an impurity band at 110 meV above the valence band. The motivation of this paper is to investigate the role of the impurity band in determining the magnetic correlations in the low-doping regime of the dilute magnetic semiconductors. For this purpose, we present results on the Haldane-Anderson model of transition-metal impurities in a semiconductor host, which were obtained by using the Hirsch-Fye Quantum Monte Carlo (QMC) algorithm. In particular, we present results on the impurity-impurity and impurity-host magnetic correlations in two and three-dimensional semiconductors with quadratic band dispersions. In addition, we use the tight-binding approximation with experimentally-determined parameters to obtain the host band structure and the impurity-host hybridization for Mn impurities in GaAs. When the chemical potential is located between the top of the valence band and the impurity bound state (IBS), the impurities exhibit ferromagnetic (FM) correlations with the longest range. We show that these FM correlations are generated by the antiferromagnetic coupling of the host electronic spins to the impurity magnetic moment. Finally, we obtain an IBS energy of 100 meV, which is consistent with the experimental value of 110 meV, by combining the QMC technique with the tight-binding approach for a Mn impurity in GaAs.Comment: 12 pages, 16 figure

Adult Intussusception Caused by an Inverted Meckel Diverticulum

Adult intussusception caused by an inverted Meckel diverticulum is rare. We report a 55-year-old Japanese man with intussusception. He was admitted to our hospital with vomiting and abdominal pain. The abdomen was hard with tenderness and muscle guarding. Computed tomography scanning demonstrated a typical inhomogeneous target-shaped mass in the right abdomen. We diagnosed intussusception and performed emergency surgery. At laparotomy, ileocolic intussusception was observed and the ileocecal segment was resected. The surgical specimen comprised an 84 cm segment of resected ileocecum with an elongated polypoid lesion measuring 11 × 2 cm within the ileal lumen. Histopathological examination demonstrated that the polypoid lesion was an inverted Meckel diverticulum. Postoperatively, the patient made an uneventful recovery

Functional tooth number and mortality

Aim: Previous studies on the association between intraoral conditions and mortality in community-dwelling older individuals reported that fewer present teeth (PT) are significant risk factors for mortality. However, how the number of PT relative to the number of functional teeth (FT), including both present and rehabilitated teeth, influences mortality has not been investigated fully. This study examined the impact of the number of FT on mortality among community-dwelling Japanese older adults. Methods: This study was a retrospective, observational and population-based follow-up study, which examined 1188 older individuals who participated in an annual geriatric health examination from 2009 to 2015. The average follow-up period was 1697.0 ± 774.5 days. The primary outcome was all-cause mortality at follow-up. The numbers of PT and FT of each participant were counted during an oral examination. In addition, demographics, clinical variables, blood nutrient markers, physical functions and perceived masticatory function were measured. Results: Kaplan–Meier analysis, followed by a log-rank test, revealed that fewer PT (P < 0.001) and FT (P = 0.002) were significantly associated with a reduced survival rate. Cox's proportional hazard analysis indicated that the number of FT, but not the number of PT, was a significant independent mortality risk factor after adjusting for demographics, clinical variables, nutrient markers and physical functioning (P = 0.036, hazard ratio: 2.089). Conclusions: Current results suggest that the number of FT more strongly predicts all-cause mortality than the number of PT among community-dwelling older adults. Further studies are necessary to consider the confounding of socioeconomic status and disability status

Number of functional teeth more strongly predicts all‐cause mortality than number of present teeth in Japanese older adults

Aim Previous studies on the association between intraoral conditions and mortality in community‐dwelling older individuals reported that fewer present teeth (PT) are significant risk factors for mortality. However, how the number of PT relative to the number of functional teeth (FT), including both present and rehabilitated teeth, influences mortality has not been investigated fully. This study examined the impact of the number of FT on mortality among community‐dwelling Japanese older adults. Methods This study was a retrospective, observational and population‐based follow‐up study, which examined 1188 older individuals who participated in an annual geriatric health examination from 2009 to 2015. The average follow‐up period was 1697.0 ± 774.5 days. The primary outcome was all‐cause mortality at follow‐up. The numbers of PT and FT of each participant were counted during an oral examination. In addition, demographics, clinical variables, blood nutrient markers, physical functions and perceived masticatory function were measured. Results Kaplan–Meier analysis, followed by a log‐rank test, revealed that fewer PT (P  Conclusions Current results suggest that the number of FT more strongly predicts all‐cause mortality than the number of PT among community‐dwelling older adults. Further studies are necessary to consider the confounding of socioeconomic status and disability status

Impact of number of functional teeth on independence of Japanese older adults

Aim To examine the relationship between the number of present and functional teeth at baseline and future incidence of loss of independence. Methods Participants were community-dwelling older individuals who participated in a comprehensive geriatric health examination conducted in Kusatsu town, Japan, between 2009 and 2015. The primary endpoint was the incidence of loss of independence among participants, defined as the first certification of long-term care insurance in Japan. The numbers of present and functional teeth at baseline were determined via an oral examination. Demographics, clinical variables (e.g., history of chronic diseases and psychosocial factors), blood nutritional markers, physical functions, and perceived masticatory function were assessed. Results This study included 1121 individuals, and 205 individuals suffered from loss of independence during the follow-up period. Kaplan–Meier estimates of loss of independence for participants with smaller numbers of present and functional teeth were significantly greater than for those with larger numbers of teeth. Cox proportional hazard analyses indicated that a smaller number of present teeth was not a significant risk factor after adjusting for demographic characteristics. However, the number of functional teeth was a significant risk factor after the adjustment (hazard ratio: 1.975 [1.168–3.340]). Additionally, higher hazard ratios were observed in other adjusted models, but they were not statistically significant. Conclusions The number of functional teeth may be more closely related to the future incidence of loss of independence than the number of present teeth. This novel finding suggests that prosthodontic rehabilitation for tooth loss possibly prevents the future incidence of this life-event