Electromagnetic spin polarization on the surface of topological insulator

We study the spin polarization of the electrons on the surface of topological insulators under a dc electric field or a circularly polarized light by using Keldysh Green's function formalism. When a dc electric field $E_x \sim 10^{3} {\rm V/m}$ is applied, a spin polarization $\simeq 5.2 \times 10^{-8}{\rm \AA^{-2}}$ is induced. Furthermore, we also find that a light illumination induces the out-of-plane component of the spin polarization as a result of the inverse Faraday effect. The magnitude of the spin polarization is proportional to the square of the lifetime $\tau$ and $\simeq 2 \times 10^{-10}{\rm \AA^{-2}}$ for typical parameters. Finally, we investigate the spin polarization in the presence of the warping term. By the symmetry consideration of the system, we find that the out-of-plane spin polarization is cubic of the current and that the magnitude of the induced spin polarization depends on the direction of the applied current.Comment: 10 pages, 6 figure

Long-Term Results of Posterior Vertebral Column Resection for Severe Thoracolumbar Kyphosis with Achondroplastic Patients: A Case Series

Background and Objectives: Thoracolumbar kyphosis is one of the most frequent skeletal manifestations in patients with achondroplasia. Few papers have been published on the surgical treatment of this condition, especially in skeletally mature patients. With this study, we presented a retrospective case series of long-term surgical results for achondroplastic patients with severe thoracolumbar kyphosis. This study was conducted to evaluate the outcome of surgical treatment for thoracolumbar kyphosis in patients associated with achondroplasia presenting with paraparesis. Materials and Methods: Three patients with achondroplasia who developed neurologic deficits due to severe thoracolumbar kyphosis and underwent surgical treatment were evaluated (mean age 22.3 years; mean follow-up 9.3 years). All patients were treated with posterior vertebral column resection (p-VCR) of hypoplastic apical vertebrae with a cage and segmental instrumentation. Neurologic outcomes (JOA scores), correction of kyphosis, and operative complications were assessed. Results: All patients had back pain, neurological deficits, and urinary disturbance before surgery. The average preoperative JOA score was 8.3/11 points, which was improved to 10.7/11 points at the final follow-up (mean recovery rate 83%). All patients obtained neurologic improvement after surgery. The mean preoperative kyphotic angle was 117 degrees (range 103 degrees-126 degrees). The postoperative angles averaged 37 degrees (range 14 degrees-57 degrees), resulting in a mean correction rate of 67%. All patients had postoperative complications such as rod breakage and/or surgical site infection. Conclusions: The long-term results of p-VCR were acceptable for treating thoracolumbar kyphosis in patients with achondroplasia. To perform this p-VCR safely, spinal navigation and neuromonitoring are inevitable when resecting non anatomical fused vertebrae and ensuring correct pedicle screw insertion. However, surgical complications such as rod breakage and surgical site infection may occur at a high rate, making informed consent very important when surgery is indicated

Lower Hb at the initiation of dialysis does not adversely affect 1-year mortality rate

Abstract Background The management of renal anemia in the pre-dialysis period has been remarkably improved by long-acting erythropoiesis-stimulating agents (ESA). However, many incident dialysis patients cannot achieve target hemoglobin (Hb) levels (> 10 g/dL) and sometimes require blood transfusions. Anemia at the time of dialysis initiation is reportedly correlated with cardiomegaly and early cardiovascular events. Here, we investigated whether this V-shaped depression in Hb level at dialysis initiation adversely affects short-term prognosis. Methods The medical charts of 166 patients who underwent initial dialysis were retrospectively reviewed for Hb level, ESA treatment status, dry weight (DW), cardiothoracic rate (CTR), and brain natriuretic peptide (BNP) level at dialysis initiation and 1 year later. Patients were subdivided into three groups according to the tertile of Hb levels. The risk of mortality within 1 year after initiation was analyzed using multivariable-adjusted Cox proportional hazard model. Result Mean Hb level at initiation was 8.6 ± 1.3 g/dL despite the administration of sufficient ESA. After initiation, Hb levels rapidly increased and the Hb time course showed a V-shape with the bottom at initiation. Hb level, CTR, and log BNP showed a significant negative correlation. The Hb level and CTR 1 year after initiation did not correlate with Hb levels at initiation. Lower Hb levels at initiation as a V-shaped depression do not adversely affect 1-year mortality rate by multivariable-adjusted Cox proportional hazard model. Conclusion Hb level around dialysis initiation showed a V-shaped depression despite ESA use. Our findings suggest that the V-shaped Hb depression at initiation does not affect short-term prognosis

GMRT observations of Jupiter's synchrotron radio emission at 610 MHz

The non-thermal decimeteric radio emission from Jupiter is dominated by synchrotron emission originating from high-energy electrons trapped in Jupiter's inner radiation belt (<5 Jovian radii). We observed Jupiter during February 24 - March 3, 2003 with the GMRT to study its day-to-day variability. Each day's observations lasted for ~10 hours (the rotation period of Jupiter). These observations suggest a correlation between the Jupiter radio flux density and the solar radio flux density at 10.7 cm (which is a proxy for solar EUV flux). Short-term variability (flux density change by 20%) seen at 610 MHz in 6-day observation seems to be due to enhanced solar EUV activity. This is the first result reporting the short-term variability in Jupiter synchrotron radiation at 610 MHz. The results have implications for Jovian radiation belt dynamics and upper atmospheric processes

G ATA2 mediates the negative regulation of the prepro-thyrotropin-releasing hormone gene by liganded T3 receptor β2 in the rat hypothalamic paraventricular nucleus.

Thyroid hormone (T3) inhibits thyrotropin-releasing hormone (TRH) synthesis in the hypothalamic paraventricular nucleus (PVN). Although the T3 receptor (TR) β2 is known to mediate the negative regulation of the prepro-TRH gene, its molecular mechanism remains unknown. Our previous studies on the T3-dependent negative regulation of the thyrotropin β subunit (TSHβ) gene suggest that there is a tethering mechanism, whereby liganded TRβ2 interferes with the function of the transcription factor, GATA2, a critical activator of the TSHβ gene. Interestingly, the transcription factors Sim1 and Arnt2, the determinants of PVN differentiation in the hypothalamus, are reported to induce expression of TRβ2 and GATA2 in cultured neuronal cells. Here, we confirmed the expression of the GATA2 protein in the TRH neuron of the rat PVN using immunohistochemistry with an anti-GATA2 antibody. According to an experimental study from transgenic mice, a region of the rat prepro-TRH promoter from nt. -547 to nt. +84 was able to mediate its expression in the PVN. We constructed a chloramphenicol acetyltransferase (CAT) reporter gene containing this promoter sequence (rTRH(547)-CAT) and showed that GATA2 activated the promoter in monkey kidney-derived CV1 cells. Deletion and mutation analyses identified a functional GATA-responsive element (GATA-RE) between nt. -357 and nt. -352. When TRβ2 was co-expressed, T3 reduced GATA2-dependent promoter activity to approximately 30%. Unexpectedly, T3-dependent negative regulation was maintained after mutation of the reported negative T3-responsive element, site 4. T3 also inhibited the GATA2-dependent transcription enhanced by cAMP agonist, 8-bromo-cAMP. A rat thyroid medullary carcinoma cell line, CA77, is known to express the preproTRH mRNA. Using a chromatin immunoprecipitation assay with this cell line where GATA2 expression plasmid was transfected, we observed the recognition of the GATA-RE by GATA2. We also confirmed GATA2 binding using gel shift assay with the probe for the GATA-RE. In CA77 cells, the activity of rTRH(547)-CAT was potentiated by overexpression of GATA2, and it was inhibited in a T3-dependent manner. These results suggest that GATA2 transactivates the rat prepro-TRH gene and that liganded TRβ2 interferes with this activation via a tethering mechanism as in the case of the TSHβ gene