63 research outputs found
One-Loop Tachyon Amplitude in Unoriented Open-Closed String Field Theory
We calculate one-loop 2-point tachyon amplitudes in unoriented open-closed
string field theory, and determine all the coupling constants of the
interaction vertices in the theory. It is shown that the planar, nonplanar and
nonorientable amplitudes are all reproduced correctly, and nontrivial
consistencies between the determined coupling constants are observed. The
necessity for the gauge group to be SO(2^{13}=8192) is also reconfirmed.Comment: 40 pages, 17 eps figures, LaTeX with PTPTeX.sty, style file replaced
once again
Photo-excitation band-structure engineering of 2H-NbSe probed by time- and angle-resolved photoemission spectroscopy
We investigated the nonequilibrium electronic structure of 2H-NbSe by
time- and angle-resolved photoemission spectroscopy. We find that the band
structure is distinctively modulated by strong photo-excitation, as indicated
by the unusual increase in the photoelectron intensities around E. In order
to gain insight into the observed photo-induced electronic state, we performed
DFT calculations with modulated lattice structures, and found that the
variation of the Se height from the Nb layer results in a significant change in
the effective mass and band gap energy. We further study the momentum-dependent
carrier dynamics. The results suggest that the relaxation is faster at the
K-centered Fermi surface than at the -centered Fermi surface, which can
be attributed to the stronger electron-lattice coupling at the K-centered Fermi
surface. Our demonstration of band structure engineering suggests a new role
for light as a tool for controlling the functionalities of solid-state
materials.Comment: 7 pages, 5 figure
Silent diabetes mellitus, periodontitis, and a new case of thalamic abscess
Brain abscess is an unusual complication of uncontrolled diabetes. A solitary thalamic abscess is an uncommon type of brain abscess. We report a case of thalamic abscess, whereupon diabetes mellitus and periodontitis were diagnosed. The diagnosis and management of thalamic abscess, and the interplay of type 2 diabetes and periodontitis are discussed. A 56-year-old, Caucasian, man with no medical or travel history, presented with 5-day symptoms of meningeal irritation. Body mass index 30.6 kg/m2. CT demonstrated a solitary midline lesion with neoplasia as a differential diagnosis. It was biopsied and cultures grew Streptococcus milleri. He was treated by stereotactic puncture, external drainage and targeted intrathecal and systemic antibiotic therapy. HIV negative but glycated haemoglobin (HbA1c) 10.7% (93 mmol/mol). Dental examination revealed a small molar abscess. Radiological resolution of the thalamic abscess occurred within 2 months. Diabetes improved with 7 weeks of insulin, and maintained on metformin, HbA1c 6.9% (51 mmol/mol). There was no residual neurological disability
Soft Coral Sarcophyton (Cnidaria: Anthozoa: Octocorallia) Species Diversity and Chemotypes
Research on the soft coral genus Sarcophyton extends over a wide range of fields, including marine natural products and the isolation of a number of cembranoid diterpenes. However, it is still unknown how soft corals produce this diverse array of metabolites, and the relationship between soft coral diversity and cembranoid diterpene production is not clear. In order to understand this relationship, we examined Sarcophyton specimens from Okinawa, Japan, by utilizing three methods: morphological examination of sclerites, chemotype identification, and phylogenetic examination of both Sarcophyton (utilizing mitochondrial protein-coding genes MutS homolog: msh1) and their endosymbiotic Symbiodinium spp. (utilizing nuclear internal transcribed spacer of ribosomal DNA: ITS- rDNA). Chemotypes, molecular phylogenetic clades, and sclerites of Sarcophyton trocheliophorum specimens formed a clear and distinct group, but the relationships between chemotypes, molecular phylogenetic clade types and sclerites of the most common species, Sarcophyton glaucum, was not clear. S. glaucum was divided into four clades. A characteristic chemotype was observed within one phylogenetic clade of S. glaucum. Identities of symbiotic algae Symbiodinium spp. had no apparent relation to chemotypes of Sarcophyton spp. This study demonstrates that the complex results observed for S. glaucum are due to the incomplete and complex taxonomy of this species group. Our novel method of identification should help contribute to classification and taxonomic reassessment of this diverse soft coral genus
IRF8 Is a Critical Transcription Factor for Transforming Microglia into a Reactive Phenotype
Microglia become activated by multiple types of damage in the nervous system and play essential roles in neuronal pathologies. However, how microglia transform into reactive phenotypes is poorly understood. Here, we identify the transcription factor interferon regulatory factor 8 (IRF8) as a critical regulator of reactive microglia. Within the spinal cord, IRF8 expression was normally low; however, the expression was markedly upregulated in microglia, but not in neurons or astrocytes, after peripheral nerve injury (PNI). IRF8 overexpression in cultured microglia promoted the transcription of genes associated with reactive states; conversely, IRF8 deficiency prevented these gene expressions in the spinal cord following PNI. Furthermore, IRF8-deficient mice were resistant to neuropathic pain, a common sequela of PNI, and transferring IRF8-overexpressing microglia spinally to normal mice produced pain. Therefore, IRF8 may activate a program of gene expression that transforms microglia into a reactive phenotype. Our findings provide a newly observed mechanism for microglial activation
Transcription factor IRF1 is responsible for IRF8-mediated IL-1β expression in reactive microglia
AbstractInterferon regulatory factor-8 (IRF8) plays a crucial role in the transformation of microglia to a reactive state by regulating the expression of various genes. In the present study, we show that IRF1 is required for IRF8-induced gene expression in microglia. Peripheral nerve injury induced IRF1 gene upregulation in the spinal microglia in an IRF8-dependent manner. IRF8 transduction in cultured microglia induced de novo gene expression of IRF1. Importantly, knockdown of the IRF1 gene in IRF8-transduced microglia prevented upregulation of interleukin-1β (IL-1β). Therefore, our findings suggest that expression of IL-1β is dependent on IRF1 in IRF8-expressing reactive microglia
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