Anisotropic Dielectric Breakdown Strength of Single Crystal Hexagonal Boron Nitride

Dielectric breakdown has historically been of great interest from the perspectives of fundamental physics and electrical reliability. However, to date, the anisotropy in the dielectric breakdown has not been discussed. Here, we report an anisotropic dielectric breakdown strength (EBD) for h-BN, which is used as an ideal substrate for two-dimensional (2D) material devices. Under a well-controlled relative humidity, EBD values in the directions both normal and parallel to the c axis (EBD+c & EBD//c) were measured to be 3 and 12 MV/cm, respectively. When the crystal structure is changed from sp3 of cubic-BN (c-BN) to sp2 of h-BN, EBD+c for h-BN becomes smaller than that for c-BN, while EBD//c for h-BN drastically increases. Therefore, h-BN can possess a relatively high EBD concentrated only in the direction parallel to the c axis by conceding a weak bonding direction in the highly anisotropic crystal structure. This explains why the EBD//c for h-BN is higher than that for diamond. Moreover, the presented EBD value obtained from the high quality bulk h-BN crystal can be regarded as the standard for qualifying the crystallinity of h-BN layers grown via chemical vapor deposition for future electronic applications

Bone erosions in rheumatoid arthritis can be repaired through reduction in disease activity with conventional disease-modifying antirheumatic drugs

We conducted the present study to determine whether repair of erosions occurs in patients with rheumatoid arthritis (RA) treated with conventional disease-modifying anti-rheumatic drugs (DMARDs) and to compare clinical characteristics between patients exhibiting and not exhibiting erosion repair. We included in the study a total of 122 RA patients who fulfilled the 1987 American College of Rheumatology criteria for RA; all patients had paired sequential radiographs of both hands and wrists showing erosive changes at baseline. Patients were classified into two groups according to the presence of repair of erosions at follow up, namely the 'repair observed' and 'repair not observed' groups. Clinical characteristics, disease activity, radiographic scores and treatment in the two groups were compared. Forty-four repairs were observed in 13 patients (10.7%). Compared with the repair not observed group, the functional class of the patients in the repair observed group was lower at baseline (P < 0.01) and the mean disease activity was lower at follow up (P < 0.005). The changes in radiographic scores per year (total radiographic score and erosion score) were lower (P < 0.05 and P < 0.01, respectively) in the repair observed group. No difference in treatment was observed. Repair of erosions was detected in 10.7% of RA patients treated with conventional DMARDs. Repairs were associated with low functional class at baseline and low disease activity at follow up. These observations support the importance of reduction in disease activity in RA patients. Because repair of erosions was detected in a substantial number of patients, assessment of erosion repair should be incorporated into the radiographic evaluation and scoring of RA

Adsorption, Desorption, Surface Diffusion, Lattice Defect Formation, and Kink Incorporation Processes of Particles on Growth Interfaces of Colloidal Crystals with Attractive Interactions

Good model systems are required in order to understand crystal growth processes because, in many cases, precise incorporation processes of atoms or molecules cannot be visualized easily at the atomic or molecular level. Using a transmission-type optical microscope, we have successfully observed in situ adsorption, desorption, surface diffusion, lattice defect formation, and kink incorporation of particles on growth interfaces of colloidal crystals of polystyrene particles in aqueous sodium polyacrylate solutions. Precise surface transportation and kink incorporation processes of the particles into the colloidal crystals with attractive interactions were observed in situ at the particle level. In particular, contrary to the conventional expectations, the diffusion of particles along steps around a two-dimensional island of the growth interface was not the main route for kink incorporation. This is probably due to the number of bonds between adsorbed particles and particles in a crystal; the number exceeds the limit at which a particle easily exchanges its position to the adjacent one along the step. We also found novel desorption processes of particles from steps to terraces, attributing them to the assistance of attractive forces from additionally adsorbing particles to the particles on the steps

Prevalence and characteristics of chronic musculoskeletal pain in Japan

AbstractBackgroundThis cross-sectional study was conducted to obtain epidemiologic data on chronic musculoskeletal pain in the Japanese people, and with it a better understanding of the actual conditions and problems involved.MethodsA questionnaire covering basic information, chronic musculoskeletal pain, daily life, quality of life, and social loss was prepared and mailed to 11507 individuals aged 18 years or older. Subjects were selected randomly nationwide in accordance with the demographic composition of Japan.ResultsThe prevalence of chronic musculoskeletal pain was 15.4%. The prevalence was highest in people in their 30s to 50s. Pain occurred most frequently in the low back, neck, shoulder, and knee. Among symptomatic subjects, 42% sought treatment, by visiting a medical institution (19%), taking folk remedies (20%), or both (3%). Treatment was generally prolonged, with 70% of those treated reporting treatment durations of more than a year. Although 69% reported that their symptoms had improved, 30% reported unchanged or aggravated symptoms and dissatisfaction with treatment. Among symptomatic subjects, a high percentage of both men and women had lost jobs, left school, been absent from work or school, or had changed jobs. Basic activities of daily living (ADL) were disturbed in men, and the instrumental ADL (IADL) score was low in women. SF-36 scale scores were significantly lower in every area for subjects with chronic pain.ConclusionsChronic musculoskeletal pain does not necessarily improve even with prolonged treatment. It adversely affects daily life and both physical and mental health. Because those suffering pain often increasingly need assistance in daily activities, people around them are also affected. The therapeutic system and treatment procedures for chronic musculoskeletal pain merit prompt review

High-redshift Ly alpha emitters with a large equivalent width: Properties of i-dropout galaxies with an NB921-band depression in the Subaru Deep Field

We report new follow-up spectroscopy of i-dropout galaxies with an NB921-band depression found in the Subaru Deep Field. The NB921-depressed i-dropout selection method is expected to select galaxies with large equivalent width Ly alpha emission over a wide redshift range, 6.0<z<6.5. Two of four observed targets show a strong emission line with a clear asymmetric profile, identified as Ly alpha emitters at z=6.11 and 6.00. Their rest-frame equivalent widths are 153A and 114A, which are lower limits on the intrinsic equivalent widths. Through our spectroscopic observations (including previous ones) of NB921-depressed i-dropout galaxies, we identified 5 galaxies in total with a rest-frame equivalent width larger than 100A at 6.0<z<6.5 out of 8 photometric candidates, which suggests that the NB921-depressed i-dropout selection method is possibly an efficient way to search for Ly alpha emitters with a large Ly alpha equivalent width, in a wider redshift range than usual narrow-band excess techniques. By combining these findings with our previous observational results, we infer that the fraction of broad-band selected galaxies having a rest-frame equivalent width larger than 100A is significantly higher at z~6 (the cosmic age of ~1 Gyr) than that at z~3 (~2 Gyr), being consistent with the idea that the typical stellar population of galaxies is significantly younger at z~6 than that at z~3. The NB921-depressed i-dropout galaxies may be interesting candidates for hosts of massive, zero-metallicity Population III stars.Comment: 9 pages, 5 figures, accepted for publication in A&

リポ多糖類処理を行ったヒト歯肉線維芽細胞の炎症反応に対する漢方薬半夏瀉心湯の予防効果

In the present study, we investigated the effects of a Kampo medicine hangeshashinto (TJ-14) on the production of prostaglandin E2 (PGE2), interleukin (IL)-6 and IL-8 by human gingival fibroblasts (HGFs) treated with lipopolysaccharide (LPS) from Porphyromonas gingivalis. HGFs proliferation was dose-dependently decreased with hangeshashinto at days 3 and 7. However, treatment with LPS (10 ng/ml), hangeshashinto (up to 1 mg/ml) and their combinations for 24 h did not affect the viability of HGFs. Hangeshashinto dose-dependently suppressed LPS-induced PGE2 production but did not alter basal PGE2 level. Hangeshashinto weakly decreased LPS-induced IL-6 and IL-8 productions. Hangeshashinto decreased cyclooxygenase (COX)-1 and COX-2 activities to approximately 60% at 1 mg/ml. Hangeshashinto decreased cytoplasmic phospholipase A2 (cPLA2) expression and LPS-induced COX-2 expression but not affected annexin1 expression. Hangeshashinto weakly suppressed LPS-induced extracellular signal-regulated kinase (ERK) phosphorylation, which is known to lead to ERK activation and cPLA2 phosphorylation. These results suggest that hangeshashinto decreased PGE2 production by (1) suppression of cPLA2 and LPS-induced COX-2 expression, and to a lesser extent, (2) inhibition of COX-2 activity and (3) inhibition of cPLA2 phosphorylation and its activation via inhibition of ERK phosphorylation. Moreover, it is also suggested that hangeshashinto may be useful to improve gingival inflammation in periodontal disease

Protein kinase A enhances lipopolysaccharideinduced IL-6, IL-8, and PGE2 production by human gingival broblasts

Objective: Periodontal disease is accompanied by inflammation of the gingiva and destruction of periodontaltissues, leading to alveolar bone loss in severe clinical cases. Interleukin (IL)-6, IL-8, and the chemical mediatorprostaglandin E2 (PGE2) are known to play important roles in inflammatory responses and tissue degradation.Recently, we reported that the protein kinase A (PKA) inhibitor H-89 suppresses lipopolysaccharide (LPS)-inducedIL-8 production by human gingival fibroblasts (HGFs). In the present study, the relevance of the PKA activity andtwo PKA-activating drugs, aminophylline and adrenaline, to LPS-induced inflammatory cytokines (IL-6 and IL-8) andPGE2 by HGFs were examined.Methods: HGFs were treated with LPS from Porphyromonas gingivalis and H-89, the cAMP analog dibutyryl cyclicAMP (dbcAMP), aminophylline, or adrenaline. After 24 h, IL-6, IL-8, and PGE2 levels were evaluated by ELISA.Results: H-89 did not affect LPS-induced IL-6 production, but suppressed IL-8 and PGE2 production. In contrast,dbcAMP significantly increased LPS-induced IL-6, IL-8, and PGE2 production. Up to 10 μg/ml of aminophylline didnot affect LPS-induced IL-6, IL-8, or PGE2 production, but they were significantly increased at 100 μg/ml. Similarly,0.01 μg/ml of adrenaline did not affect LPS-induced IL-6, IL-8, or PGE2 production, but they were significantlyincreased at concentrations of 0.1 and 1 μg/ml. In the absence of LPS, H-89, dbcAMP, aminophylline, andadrenaline had no relevance to IL-6, IL-8, or PGE2 production.Conclusion: These results suggest that the PKA pathway, and also PKA-activating drugs, enhance LPS-induced IL-6,IL-8, and PGE2 production by HGFs. However, aminophylline may not have an effect on the production of thesemolecules at concentrations used in clinical settings (8 to 20 μg/ml in serum). These results suggest thataminophylline does not affect inflammatory responses in periodontal disease