23 research outputs found

    Multi-wavelength Stellar Polarimetry of the Filamentary Cloud IC5146: I. Dust Properties

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    We present optical and near-infrared stellar polarization observations toward the dark filamentary clouds associated with IC5146. The data allow us to investigate the dust properties (this paper) and the magnetic field structure (Paper II). A total of 2022 background stars were detected in RcR_{c}-, ii'-, HH-, and/or KK-bands to AV25A_V \lesssim 25 mag. The ratio of the polarization percentage at different wavelengths provides an estimate of λmax\lambda_{max}, the wavelength of peak polarization, which is an indicator of the small-size cutoff of the grain size distribution. The grain size distribution seems to significantly change at AVA_V \sim 3 mag, where both the average and dispersion of PRc/PHP_{R_c}/P_{H} decrease. In addition, we found λmax\lambda_{max} \sim 0.6-0.9 μ\mum for AV>2.5A_V>2.5 mag, which is larger than the \sim 0.55 μ\mum in the general ISM, suggesting that grain growth has already started in low AVA_V regions. Our data also reveal that polarization efficiency (PE Pλ/AV\equiv P_{\lambda}/A_V) decreases with AVA_V as a power-law in RcR_c-, ii'-, and KK-bands with indices of -0.71±\pm0.10, -1.23±\pm0.10 and -0.53±\pm0.09. However, HH-band data show a power index change; the PE varies with AVA_V steeply (index of -0.95±\pm0.30) when AV<2.88±0.67A_V < 2.88\pm0.67 mag but softly (index of -0.25±\pm0.06) for greater AVA_V values. The soft decay of PE in high AVA_V regions is consistent with the Radiative Aligned Torque model, suggesting that our data trace the magnetic field to AV20A_V \sim 20 mag. Furthermore, the breakpoint found in HH-band is similar to the AVA_V where we found the PRc/PHP_{R_c}/P_{H} dispersion significantly decreased. Therefore, the flat PE-AVA_V in high AVA_V regions implies that the power index changes result from additional grain growth.Comment: 31 pages, 17 figures, and 3 tables; accepted for publication in Ap

    Iodine and GPXs involved in Thyroid Hormones Biosynthesis.

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    <p>The serum sodium iodide is transported into the thyrocyte and then iodine is incorporated into the thyroglobulin molecule (Tg) in a reaction catalyzed by the hemoprotein thyroid peroxidase (TPO). In this reaction, H<sub>2</sub>O<sub>2</sub> generated by the NADPH-dependent thyroxidase (ThOx) is required as substrate by TPO for the iodination and coupling of tyrosyl residues in Tg. Then, thyroid hormones triiodothyronine (T3) and tetraiodothyronine (T4) are released into the bloodstream. H<sub>2</sub>O<sub>2</sub> used in this reaction decreases the amount of H<sub>2</sub>O<sub>2</sub> that would otherwise be available for damaging oxidation reactions. Selenium-dependent glutathione peroxidase 1 (<i>GPX 1</i>) and other GPX s remove H<sub>2</sub>O<sub>2</sub> from the tissues, also decreasing oxidative damage. (Modified from: J. Köhrle <i>et al</i>. Selenium, the thyroid, and the endocrine system. Endocrine Reviews, December 2005, 26(7):944–984; Lyn Patrick, ND. Iodine: deficiency and therapeutic considerations. Alternative Medicine Review, 2008, 13(2):116–127).</p

    Clinical features of KBD patients.

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    <p>A. A female KBD patient with her knee, ankle and toe joints deformity, the arrows show multiple joints of this patient are affected. B. A male KBD patient with his fingers joints deformity. C. The X-ray picture of a KBD patient's hand.</p

    A novel deletion downstream of the <i>PAX6</i> gene identified in a Chinese family with congenital aniridia

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    <p><b>Purpose</b>: Congenital aniridia, a severe bilateral panocular visual disorder, is an autosomal dominantly inherited eye anomaly. Mutations in the <i>paired box 6</i> gene (<i>PAX6</i>) have been shown to be responsible for congenital aniridia in most patients. The purpose of the present study was to report clinical features of a Chinese family with congenital aniridia and to screen novel genetic mutations for congenital aniridia.</p> <p><b>Methods</b>: All members of a three-generation family underwent comprehensive ophthalmic examination, and 8 of its 25 members were diagnosed with congenital aniridia. The proband was analyzed by exome sequencing and whole genome sequencing, and linkage analysis was performed for the family. The mutation was confirmed by direct DNA sequencing.</p> <p><b>Results</b>: Using Illumina’s Human Linkage-12 beadchip microarray (including 6090 SNPs) whole genome scan, the LOD score value showed that the interval on chromosome 11 between rs1389423 to rs910090 exhibited a strong linkage. A novel heterozygous 469 kb deletion mutation within the downstream region of <i>PAX6</i> (chr11:31189937–31659379) was identified in all affected family members, but not in unaffected family members or 2000 ethnically matched controls.</p> <p><b>Conclusion</b>: A novel deletion mutation was identified within the <i>PAX6</i> downstream region that results in congenital aniridia.</p