Horizontal Arrays of One-Dimensional van der Waals Heterostructures as Transistor Channels.

The nanotube/dielectric interface plays an essential role in achieving superb switching characteristics of carbon nanotube-based transistors for energy-efficient computation. Formation of van der Waals heterostructures with hexagonal boron nitride nanotubes could be an effective means to reduce interface state density, but the need for isolating nanotubes during the formation of coaxial outer layers has hindered the fabrication of their horizontal arrays. Here, we develop a strategy to create isolated heterostructure arrays using aligned carbon nanotubes grown on a quartz substrate as starting materials. Air-suspended arrays of carbon nanotubes are prepared by a dry transfer technique and then used as templates for the coaxial wrapping of boron nitride nanotubes. We then fabricate the transistors, where boron nitride serves as interfacial layers between carbon nanotube channels and conventional gate dielectrics, showing hysteresis-free characteristics owing to the improved interfaces. We have also gained a deeper understanding of the strain applied on inner carbon nanotubes, as well as the inhomogeneity of the outer coating, by characterizing individual heterostructures over trenches and on a substrate surface. The device fabrication and characterization presented here essentially do not require elaborate electron microscopy, thus paving the way for the practical use of one-dimensional van der Waals heterostructures for nanoelectronics.

Filobacterium rodentium gen. nov., sp. nov., a member of Filobacteriaceae fam. nov. within the phylum Bacteroidetes; includes a microaerobic filamentous bacterium isolated from specimens from diseased rodent respiratory tracts.

Strain SMR-CT, which was originally isolated from rats as the SMR strain, had been named 'cilia-associated respiratory bacillus' ('CAR bacillus'). 'CAR bacillus' was a Gram-stain-negative, filamentous argentophilic bacterium without flagella. SMR-CT grew at 37 °C under microaerobic conditions, showed gliding activity, hydrolysed urea and induced chronic respiratory diseases in rodents. The dominant cellular fatty acids detected were iso-C15 : 0 and anteiso-C15 : 0. The DNA G+C content was 47.7 mol%. 16S rRNA gene sequence analysis revealed SMR-CT and other strains of 'CAR bacillus' isolated from rodents all belonged to the phylum Bacteroidetes. The nearest known type strain, with 86 % 16S rRNA gene sequence similarity, was Chitinophaga pinensis DSM 2588T in the family Chitinophagaceae. Strain SMR-CT and closely related strains of 'CAR bacillus' rodent-isolates formed a novel family-level clade in the phylum Bacteroidetes with high bootstrap support (98-100 %). Based on these results, we propose a novel family, Filobacteriaceae fam. nov., in the order Sphingobacteriales as well as a novel genus and species, Filobacterium rodentium gen. nov., sp. nov., for strain SMR-CT. The type strain is SMR-CT ( = JCM 19453T = DSM 100392T).

Significant association between hypolipoproteinemia(a) and lifetime risk of cancer: an autopsy study from a community-based Geriatric Hospital.

BACKGROUND: Our recent study showed that a low lipoproteinemia(a) [Lp(a)] level was a risk factor for cancer and all-cause deaths. The purpose of this study was to verify the role of the Lp(a) level on cancer among consecutive autopsy cases. METHODS: The subjects consisted of 1354 cases (775 men and 579 women). The average age at death was 79.9 years. Hypolipoproteinemia(a) was defined as an Lp(a) level of below 80 mg/L. Overall, 62.3% of the subjects had suffered from at least one to a maximum of five malignancies throughout their lives. The most frequent type of malignancy was gastric cancer, followed by leukemia, lung cancer, and colon cancer. RESULTS: The cancer-bearing status decreased linearly according to the Lp(a) level in both men and women (P=0.01 and P<0.001, respectively). The median Lp(a) level was significantly lower among the cases with hepato-biliary-pancreatic cancers or hematopoietic malignancy, but was higher among cases with lung cancer, especially lung adenocarcinoma. Hypolipoproteinemia(a) was a significant risk factor for any origins of cancer, with an odds ratio of 1.94 (95% CI, 1.45-2.60; P<0.001). It was also a risk factor for hepato-biliary cancers and leukemia, but it was a protective factor for lung cancer. CONCLUSIONS: Our findings suggested hypolipoproteinemia(a) would be a significant risk factor for cancer except lung cancer. This study complements our previous study showing that hypolipoproteinemia(a) would increase the lifetime risk of cancer other than lung cancer.

Low lipoprotein(a) concentration is associated with cancer and all-cause deaths: a population-based cohort study (the JMS cohort study).

BACKGROUND: Experimental studies support the anti-neoplastic effect of apo(a), but several clinical studies have reported contradictory results. The purpose of this study was to determine whether a low lipoprotein(a) [Lp(a)] concentration is related to mortality from major causes of death, especially cancer. METHODS: The subjects were 10,413 participants (4,005 men and 6,408 women) from a multi-center population-based cohort study in Japan (The Jichi Medical School cohort study). The average age at registration was 55.0 years, and the median observation period was 4,559 days. As the estimated hazard ratio was high for both the low and very high Lp(a) levels, we defined two Lp(a) groups: a low Lp(a) group [Lp(a)<80 mg/L] and an intermediate-to-high Lp(a) group [Lp(a) ≥ 80]. Participants who died from malignant neoplasms (n = 316), cardiovascular disease (202), or other causes (312) during the observation period were examined. RESULTS: Cumulative incidence plots showed higher cumulative death rates for the low Lp(a) group than for the intermediate-to-high Lp(a) group for all-cause, cancer, and miscellaneous-cause deaths (p<0.001, p = 0.03, and p = 0.03, respectively). Cox proportional hazards analyses with the sex and age of the participants, body mass index, and smoking and drinking histories as covariates showed that a low Lp(a) level was a significant risk for all-cause, cancer, and miscellaneous-cause deaths (p<0.001, p = 0.003, and p = 0.01, respectively). The hazard ratio (95% CI) [1.48, 1.15-1.92] of a low Lp(a) level for cancer deaths was almost the same as that for a male sex (1.46, 1.00-2.13). CONCLUSIONS: This is the first report to describe the association between a low Lp(a) level and all-cause or cancer death, supporting the anti-neoplastic effect of Lp(a). Further epidemiological studies are needed to confirm the present results.

Evaluation of new cage lid with partitioning barrier based on transmission of CAR bacillus in mice.

We developed a new cage lid made of stainless steel wire mesh and having a screen barrier for partitioning a small laboratory animal cage into compartments. To evaluate the effectiveness of the lid, we tested the transmissibility of Cilia-Associated Respiratory (CAR) bacillus from infected mice to uninfected sentinel mice, which were kept in separate compartments using this lid. Infection from the infected mice to the uninfected mice was confirmed by microbiological, serological, pathological, and molecular diagnostic examinations, as previously observed in an intra-cage contact route. The cage lid that we developed is very useful when uninfected mice are used in quarantine and contagion experiments to prevent fighting among the mice.

Colitis associated with Clostridium difficile in specific-pathogen-free C3H-scid mice.

Soft feces and a decreased delivery rate were observed in a specific-pathogen-free (SPF) C3H-scid mouse breeding colony. Grossly, the ceca were shrunken and edematous in the affected mice. Histopathologically, severe edema in the cecal submucosa as well as infiltration of inflammatory cells in the lamina propria and submucosa of the ceca and colon were observed. No pathogenic microorganisms were detected by the routine microbiological tests. By anaerobic bacterial-examination, Clostridium (C.) difficile with toxin A was isolated from the cecal contents of the affected mice. The mice were diagnosed with C. difficile-associated colitis. This case appears to be the first report of natural infection with C. difficile in SPF mice with clinical signs.

Aortic pulse wave velocity and the degree of atherosclerosis in the elderly: a pathological study based on 304 autopsy cases.

INTRODUCTION: Studies examining the correlation between aortic pulse wave velocity (PWV) and atherosclerosis have reported conflicting results. The present paper verifies this correlation by conducting autopsy examination of elderly subjects. METHODS: A total of 3456 PWV examinations had been performed on 1538 elderly people, as a part of routine physical check-up. During long-term follow-up, many of these subjects died, and autopsy study could be conducted on 304 of these subjects. The average age at death of the subjects was 83 years and the male: female ratio was 6:5. The pathological atherosclerotic index (PAI) was defined as the average pathological degree of atherosclerosis in eight large arteries, including aorta. RESULTS: Significant positive correlations were observed between the age and PWV (gamma=0.273, P<0.001), and between the systolic blood pressure and PWV (gamma=0.478, P<0.001). There was a significantly positive correlation between the aortic atherosclerotic degree and mean PWV (rho=0.239, P<0.005), and between the PAI and mean PWV (gamma=0.323, P<0.001). The partial regression coefficient between the PAI and mean PWV was 0.209, after adjusting for the mean systolic blood pressure and age at death. CONCLUSION: The present study proved a weak correlation between the PWV and the pathologically verified degree of the aortic and systemic atherosclerosis.

Age-related mitochondrial DNA deletion in human heart: its relationship with cardiovascular diseases.

BACKGROUND AND AIMS: Accumulation of damage to mitochondrial DNA (mtDNA) occurs in myocardial tissue with advancing age. However, despite higher incidence of cardiac diseases in the elderly, little attempt has been made to detect deletions of mtDNA in the myocardial tissue of aged individuals. The aim of the present study was to clarify the relationship between aging, mtDNA deletion and cardiovascular (CV) diseases. METHODS: We examined 163 autopsy cases, aged 60 years or older, using two different kinds of polymerase chain reaction (PCR): highly sensitive PCR to detect a common 4977-bp deletion and long-PCR for multiple deletions, which could be detected in case that deleted mtDNA accounted for more than several percents in total mtDNA. RESULTS: The common 4977-bp deletion was detected in 156 cases (95.7%), showing no significant difference among these age groups and no relation to CV diseases. By long-PCR, multiple deletions in cardiac mtDNA were found in 33 (20.2%) of 163 cases. The proportion of the mtDNA deletion in the nineties (46.2%) was significantly higher than those in the younger (15.3%, p < 0.05). Female predominance was significantly found in the group with the mtDNA deletion (p < 0.05). Multiple deletions of mtDNA were not significantly related to ischemic change, valvular diseases, left ventricular hypertrophy, congestive heart failure, coronary sclerosis, or heart weight except for right ventricular hypertrophy. CONCLUSIONS: These findings suggest that there is a close relationship between aging and deletion of mtDNA, and that the ratio of deleted mtDNA to total mtDNA increases with advancing age. Age-related deletion of mtDNA may have little influence on CV diseases except for right ventricular hypertrophy.

Neuropathology of delayed encephalopathy in cats induced by heavy-ion irradiation.

AIM: The pathogenesis of delayed encephalopathy induced by heavy-ion irradiation was investigated experimentally in cats. The left cerebral hemispheres were irradiated with 15-40 Gy of heavy ions (carbon), and histologically and morphometrically examined 12 months later. RESULTS: In the irradiated cerebral white matter the following occurred as the dose increased: astrocytic swelling, then the dilatation of small blood vessels with a fibrous thickening of the wall, and then loosening of the white matter with cavity formation and diffuse albumin deposition. Pathological features of these cavities suggested that they are induced by long-standing edema. Although the dilated vessels were arteries, veins, and capillaries, arteriovenous shunt and damage of the smooth muscle cells of the arterial media were absent. Changes of the cerebral cortex were scarce. Morphometrically, the irradiated cerebral white matter was swollen, and the capillary density tended to be reduced in the deep cortex and subcortical white matter, but this effect was not dose dependent. CONCLUSION: Heavy-ion irradiation induces delayed encephalopathy in cats, preferentially involving the white matter. The cardinal pathogenesis was long-standing edema of the white matter due to vascular hyperpermeability, and the vascular dilatation seemed to be caused by a reduction in the vascular bed and/or hemoconcentration due to hyperpermeability.