Our scanning tunneling microscopy and electron diffraction experiments revealed that a new twodimensional allotrope of Bi forms on the Si111-7 7 surface. This pseudocubic f012g-oriented allotrope is stable up to four atomic layers at room temperature. Above this critical thickness, the entire volume of the film starts to transform into a bulk single-crystal (001) When the size and shape of the materials are downsized to a nanometer scale, they often reveal anomalous atomic structures as well as exotic functional properties that do not exist in bulk. A variety of novel structures discovered in nanoparticles and nanowires have been attracting broad interest [1][2][3][4]. Group V elements are known to show rich allotropic transformation because their semimetallic bonding character can be easily shifted to either the metallic or covalent side, for example, by changing the applied pressure [5][6][7][8]. In this context, a question arises whether a new allotrope can be realized by tuning the dimensionality or size, such as thickness of the film, instead of tuning the pressure or temperature.In this Letter, we report on our finding that ultrathin film of Bi really shows such an allotropic transformation as a function of thickness on the scale of several atomic layers. Our electron diffraction and scanning tunneling microscopy (STM) experiments revealed that, over the wetting layer formed initially on the Si111-7 7 surface, Bi grows with a new f012g-oriented phase whose structure is significantly different from bulk Bi and that it transforms into the bulk-like single-crystal Bi(001) phase above the critical thickness which increases with the substrate temperature. Our ab initio theory revealed that the f012g phase with even-number layers is stabilized by forming a puckered-layer structure. The resulting film is very flat, compared to the growth of any known metal films, reflecting the inherent two-dimensional (2D) structure of this f012g phase. To the best of our knowledge, puckered-layer structure was never observed before except for the case of black phosphorus, which is a famous teratoid phase in group V elements.Bismuth ultrathin films were grown in ultrahigh vacuum (UHV) and characterized in situ using STM and reflection high-energy electron diffraction (RHEED). The spot-profile-analyzing low-energy electron diffraction (SPA-LEED) was performed with momentum reso-

The electronic structure of Bi(001) ultrathin films (thickness > or =7 bilayers) on Si(111)-7x7 was studied by angle-resolved photoemission spectroscopy and first-principles calculations. In contrast with the semimetallic nature of bulk Bi, both the experiment and theory demonstrate the metallic character of the films with the Fermi surface formed by spin-orbit-split surface states (SSs) showing little thickness dependence. Below the Fermi level, we clearly detected quantum well states (QWSs) at the M point, which were surprisingly found to be non-spin-orbit split; the films are "electronically symmetric" despite the obvious structural nonequivalence of the top and bottom interfaces. We found that the SSs hybridize with the QWSs near M and lose their spin-orbit-split character.

1] on our Letter [2], Watkins shows his confidence that large pairing distortion (LPD) takes place instead of the resonant-bond distortion (RBD) in the divacancy (U2) for both V2+ and V2 . His assertion is based on the EPR measurement beautifully carried out by Watkins and Corbett in the 1960s [3]: They have established that the pairing distortion is consistent with the EPR spectra under uniaxial stress. We still argue, however, that the RBD occurs for V2 and the small pairing distortion occurs for V&+, based on our careful total-energy calculations newly performed and on a notion that the RBD is not inconsistent with the EPR measurement under uniaxial stress.In order to reexamine our finding that the pairing distortion is small in the divacancy, we newly perform more careful total-energy calculations within the local density approximation (LDA): We carry out more extensive search for stable geometries and also increase the number of k points in the Brillouin zone integration. Again we obtain the results of a small size of the pairing distortion: The distance (l23) between the pairing atoms is 3.48 A (3.55 A in Ref.[2]) for U2, the unoccupied ag level which splits from the upper e~l evel is found to have much higher energy (0.41 eV) than the a, level, the upper partner of the b" level split from the e, level. It is noteworthy, however, that a metastable geometry in which a relatively LPD (l23 = 2.93 A) takes place is found when we perform a restricted LDA calculation by enforcing the electron configuration as b"a, a'. This excited geometry is 0.26 eV higher in total energy than the small pairing geometry and is thus energetically unfavorable.In spite of this large distortion, the a~l evel is still located above the a, level by 0.06 eV. When we render the pairing atoms closer (e.g., lq3 = 2.81 A), the energetical order of the a, and ag levels is reversed. However, we do not find any stable geometry with b, a'a, . The results here, along with the previous results [2], are indicative that the LDA scheme does not produce the stable geometry accornpanied with the LPD in Ref. [3].What should be addressed then is the compatibility between the RBD and the EPR experiment with uniaxial stress [3]: The stress along the particular axis of (110) induces the total-energy difference among orientations of the defects in a crystal and this energy difference is observed from Boltzmann distribution of the EPR line intensity corresponding to each orientation.It is found from the observation for V2+ and V2 that the defect in which the stress reduces the distance l23 between the nearest two atoms on the pairing axis (this orientation is denoted by ad in Ref. [3]) has lower energy than that in which the stress reduces another distance (l~2 or l~3) between two of three neighboring nearest atoms (ab) We. certainly agree with the notion that the pairing distortion model is consistent with the experimental result (our new calculation on V2 actually shows that the defect of ad has lower energy by -0.01 eV than that of ab). We do not ag...

Although 12 of 58 patients (21%) had an infection, pretransplantation immunization was effective to prevent serious illness, especially for the 6 months after transplantation. Posttransplantation live-vaccine administration under immunosuppressive conditions is effective and safe.

RBM20 is a major regulator of heart-specific alternative pre-mRNA splicing of TTN encoding a giant sarcomeric protein titin. Mutation in RBM20 is linked to autosomal-dominant familial dilated cardiomyopathy (DCM), yet most of the RBM20 missense mutations in familial and sporadic cases were mapped to an RSRSP stretch in an arginine/serine-rich region of which function remains unknown. In the present study, we identified an R634W missense mutation within the stretch and a G1031X nonsense mutation in cohorts of DCM patients. We demonstrate that the two serine residues in the RSRSP stretch are constitutively phosphorylated and mutations in the stretch disturb nuclear localization of RBM20. Rbm20S637A knock-in mouse mimicking an S635A mutation reported in a familial case showed a remarkable effect on titin isoform expression like in a patient carrying the mutation. These results revealed the function of the RSRSP stretch as a critical part of a nuclear localization signal and offer the Rbm20S637A mouse as a good model for in vivo study.

SUMMARYPeriodontitis is an inflammatory bone disease caused by Gram-negative anaerobic bacteria, but the precise mechanism of bone destruction remains unknown. Activated T lymphocytes secrete receptor activator of NF-k B ligand (RANKL) and support the differentiation of monocytes into mature osteoclasts. The purpose of this study was to examine the expression of RANKL and its inhibitor, osteoprotegerin (OPG), in inflamed gingival tissue and to clarify the role of human gingival fibroblasts (HGFs) in osteoclastogenesis regulated by RANKL. HGFs and gingival mononuclear cells (GMCs) were obtained from chronic periodontitis patients during routine periodontal surgery. Expression of OPG and RANKL mRNA in gingival tissue and HGFs was examined with RT-PCR. OPG production was measured using ELISA. Expression of RANKL, CD4, CD8 and CD69 on GMCs was determined by flow-cytometry using RANK-Fc fusion protein and the respective monoclonal antibodies. Osteoclastogenesis by RANKL was assayed by counting the number of tartarate-resistant acid phosphatase (TRAP)-positive cells after culturing human peripheral blood monocytes with recombinant human RANKL and macrophage-colony stimulating factor (M-CSF) for 10 days. OPG and RANKL mRNA were expressed in 80% (16/20) and 25% (5/20) of periodontitis lesions, respectively. OPG, but not RANKL, mRNA was expressed within HGFs. OPG mRNA expression and production by HGFs was augmented by LPS stimulation. All GMC samples expressed CD69, and two of five GMC samples expressed RANKL. The culture supernatant of LPS-stimulated gingival fibroblasts significantly reduced the number of TRAP positive cells generated by culturing monocytes with RANKL and M-CSF. The present study suggests that LPS-stimulated HGFs inhibit monocyte differentiation into osteoclasts through the production of OPG.

Background: Systemic corticosteroids are one of the most commonly used therapeutic modalities for patients with extensive alopecia areata (AA), although they entail several drawbacks. Objective: To determine the best modality for systemic corticosteroid use in terms of their efficacy, relapse rate, and side effects. Methods: Fifty-one patients with single or multiple AA (AA/multiplex) and 38 patients with alopecia totalis or AA universalis (AA totalis/universalis) were enrolled in this open study. They were randomly divided into three groups depending on the time of their initial visit. They were administered (1) oral dexamethasone (Dex) 0.5 mg/day for 6 months (Dex group), (2) intramuscular triamcinolone acetonide (imTA) 40 mg once a month for 6 months followed by 40 mg once every 1.5 months for 1 year (imTA group), and (3) pulse therapy (PT) using oral predonine 80 mg for 3 consecutive days once every 3 months (PT group). After the treatment, each treatment modality was evaluated by the response rate, relapse rate, and side effect profile. Results: The response rate of AA/multiplex was significantly better in the imTA group than in the Dex group. The overall relapse rate and that of AA totalis/universalis were significantly better in the PT group than in the Dex group. Dysmenorrhea was the most common and problematic side effect. Impairment of the adrenocortical reserve was seen in 7% of the PT group and 23% of the imTA group, which was recov ered without any further medical treatment. Conclusion: imTA or pulse therapy is effective for AA and has an acceptable level of side effects. The development of a new strategy to reduce the relapse rate is needed.

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