Line nodes, Dirac points and Lifshitz transition in 2D nonsymmorphic photonic crystals

Topological phase transitions, which have fascinated generations of physicists, are always demarcated by gap closures. In this work, we propose very simple 2D photonic crystal lattices with gap closure points, i.e. band degeneracies protected by nonsymmorphic symmetry. Our photonic structures are relatively easy to fabricate, consisting of two inequivalent dielectric cylinders per unit cell. Along high symmetry directions, they exhibit line degeneracies protected by glide reflection symmetry, which we explicitly demonstrate for $pg,pmg,pgg$ and $p4g$ nonsymmorphic groups. In the presence of time reversal symmetry, they also exhibit point degeneracies (Dirac points) protected by a $Z_2$ topological number associated with crystalline symmetry. Strikingly, the robust protection of $pg$-symmetry allows a Lifshitz transition to a type II Dirac cone across a wide range of experimentally accessible parameters, thus providing a convenient route for realizing anomalous refraction. Further potential applications include a stoplight device based on electrically induced strain that dynamically switches the lattice symmetry from $pgg$ to the higher $p4g$ symmetry. This controls the coalescence of Dirac points and hence the group velocity within the crystal.Comment: 11 pages, 8 figures, 3 table

Effects of mycophenolate mofetil on cutaneous lupus erythematosus in (NZB × NZW) F1 mice

AbstractBackgroundFew studies have evaluated the effects and precise molecular mechanism of mycophenolate mofetil (MMF) in the treatment of human cutaneous lupus erythematosus (CLE). Our findings shed light on the therapeutic effects of MMF in a UVB-induced NZB × NZW (NZBW) F1 CLE mouse model.MethodsContinuous MMF treatment (60 mg/kg/day) was administered up to Day 50 from the beginning of UVB induction (Day 0; 20 weeks old), as the pathologic features of CLE are present after 50 days. The therapeutic effects of MMF treatment in NZBW lupus mice were examined by comparing histopathological changes, lupus band test (deposition of immune complexes at the dermal–epidermal junction) and colocalization of autoantibodies with a dermal autoantigen Dsg3, and by evaluating the associations of local matrix metalloprotease activities.ResultsMMF improved survival in the NZBW lupus mice from 35.7% to 81.8%. The proteinuria, blood urea nitrogen, and interleukin 6 levels were significantly reduced after MMF treatment. The dermal lymphocytic infiltration, deposition of immune complexes at the dermal–epidermal junction, colocalized autoantibodies with Dsg3, and epidermal matrix metalloprotease activity were also attenuated in MMF-treated NZBW F1 mice.ConclusionThe results confirmed that MMF could substantially attenuate skin damage due to CLE in the NZBW F1 mouse model

Fucosyltransferase 1 and 2 play pivotal roles in breast cancer cells.

FUT1 and FUT2 encode alpha 1, 2-fucosyltransferases which catalyze the addition of alpha 1, 2-linked fucose to glycans. Glycan products of FUT1 and FUT2, such as Globo H and Lewis Y, are highly expressed on malignant tissues, including breast cancer. Herein, we investigated the roles of FUT1 and FUT2 in breast cancer. Silencing of FUT1 or FUT2 by shRNAs inhibited cell proliferation in vitro and tumorigenicity in mice. This was associated with diminished properties of cancer stem cell (CSC), including mammosphere formation and CSC marker both in vitro and in xenografts. Silencing of FUT2, but not FUT1, significantly changed the cuboidal morphology to dense clusters of small and round cells with reduced adhesion to polystyrene and extracellular matrix, including laminin, fibronectin and collagen. Silencing of FUT1 or FUT2 suppressed cell migration in wound healing assay, whereas FUT1 and FUT2 overexpression increased cell migration and invasion in vitro and metastasis of breast cancer in vivo. A decrease in mesenchymal like markers such as fibronectin, vimentin, and twist, along with increased epithelial like marker, E-cadherin, was observed upon FUT1/2 knockdown, while the opposite was noted by overexpression of FUT1 or FUT2. As expected, FUT1 or FUT2 knockdown reduced Globo H, whereas FUT1 or FUT2 overexpression showed contrary effects. Exogenous addition of Globo H-ceramide reversed the suppression of cell migration by FUT1 knockdown but not the inhibition of cell adhesion by FUT2 silencing, suggesting that at least part of the effects of FUT1/2 knockdown were mediated by Globo H. Our results imply that FUT1 and FUT2 play important roles in regulating growth, adhesion, migration and CSC properties of breast cancer, and may serve as therapeutic targets for breast cancer

Comparing the Behavioral Models in Cyber-World Using Social Roles

Cyber-world is a typical form of social syndication. Although the future of cyber-world seems bright, not all efforts have succeeded. Therefore, knowing how to motivate users and keep them continually visiting is an important challenge for creating successful cyber-world Web sites. Since that human behaviour varies according to people’s different social roles, this study investigated four social roles (habitual, active, personal, and lurker) in the cyber-worlds. 729 users of i-Partment were used to test the research model. This study empirically confirms the existence of different behavioural models, and revealed the implications for theory and practice

Exploring users’ behavioral model in Web 2.0 applications - The moderating effects of hedonic versus utilitarian motivations

The Web 2.0 trend has enhanced the overwhelming demand for more pervasive human space in online social interaction. Therefore, it is imperative for the practitioners of Web 2.0 websites to understand users’ motivations to participate and develop specific services to stimulate a long-term usage. This study has proposed a research model that explores the factors affecting users’ intentions to use Web 2.0 applications. In addition, user’s usage motivations (i.e. hedonic versus utilitarian) are also compared. The results revealed that users’ intentions to use Web 2.0 applications is influenced by usefulness, ease of use, enjoyment, and social presence. In addition, users’ hedonic versus utilitarian motivations has the moderating influences on the research model

Structural and cognitive deficits in chronic carbon monoxide intoxication: a voxel-based morphometry study

BACKGROUND: Patients with carbon monoxide (CO) intoxication may develop ongoing neurological and psychiatric symptoms that ebb and flow, a condition often called delayed encephalopathy (DE). The association between morphologic changes in the brain and neuropsychological deficits in DE is poorly understood. METHODS: Magnetic resonance imaging and neuropsychological tests were conducted on 11 CO patients with DE, 11 patients without DE, and 15 age-, sex-, and education-matched healthy subjects. Differences in gray matter volume (GMV) between the subgroups were assessed and further correlated with diminished cognitive functioning. RESULTS: As a group, the patients had lower regional GMV compared to controls in the following regions: basal ganglia, left claustrum, right amygdala, left hippocampus, parietal lobes, and left frontal lobe. The reduced GMV in the bilateral basal ganglia, left post-central gyrus, and left hippocampus correlated with decreased perceptual organization and processing speed function. Those CO patients characterized by DE patients had a lower GMV in the left anterior cingulate and right amygdala, as well as lower levels of cognitive function, than the non-DE patients. CONCLUSIONS: Patients with CO intoxication in the chronic stage showed a worse cognitive and morphologic outcome, especially those with DE. This study provides additional evidence of gray matter structural abnormalities in the pathophysiology of DE in chronic CO intoxicated patients

A WORLD OF PARADOX: IS THAT THE PUBLIC STATEMENT OR PRIVATE TALK IN VIRTUAL COMMUNITY?

Past studies mostly suggest that virtual community be the platform especially applicable for private exchange because people express themselves through hiding their real images and identities in online interaction. On the other hand, the anonymously private opinions at cyberspace are easily cited and forwarded as public ones because of the powerful search engines and hyperlink connections of internet. We consider that both public and private aspects coexist in the interaction of virtual community. This study is conducted as an interpretive research and uses the views of “front region” and “back region” in dramaturgical theory to unobtrusively observe a virtual community. We analyze the data upon hermeneutic circle to find out that the point of reference of the stage in virtual community is shaky. The virtual community can be both public and private channel at the same time just as the front region and back region overlapping. We also expect that the administrative team of every virtual community recognize the subject matter and elaborate an appropriate online environment for their members