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Probing the nature of high‐<i>z</i> short GRB 090426 with its early optical and X‐ray afterglows
Xin, Li‐,Ping,Liang, En‐,Wei,Wei, Jian‐,Yan,Zhang, Bing,Lv, Hou‐,Jun,Zheng, Wei‐,Kang,Urata, Yuji,Im, Myungshin,Wang, Jing,Qiu, Yu‐,Lei,Deng, Jin‐,Song,Huang, Blackwell Publishing Ltd 2011 MONTHLY NOTICES- ROYAL ASTRONOMICAL SOCIETY Vol.410 No.1
<P><B>ABSTRACT</B></P><P>GRB 090426 is a short‐duration burst detected by <I>Swift</I> (<IMG src='/wiley-blackwell_img/equation/MNR_17419_mu1.gif' alt ='inline image'/> s in the observer frame and <IMG src='/wiley-blackwell_img/equation/MNR_17419_mu2.gif' alt ='inline image'/> s in the burst frame at <I>z</I>= 2.609). Its host galaxy properties and some gamma‐ray‐related correlations are analogous to those seen in long‐duration gamma‐ray bursts (GRBs), which are believed to be of a massive star origin (so‐called Type II GRBs). We present the results of its early optical observations with the 0.8‐m Tsinghua University–National Astronomical Observatory of China Telescope (TNT) at Xinglong Observatory and the 1‐m LOAO telescope at Mt Lemmon Optical Astronomy Observatory in Arizona. Our well‐sampled optical afterglow light curve covers from <IMG src='/wiley-blackwell_img/equation/MNR_17419_mu3.gif' alt ='inline image'/> to 10<SUP>4</SUP> s after the GRB trigger. It shows two shallow decay episodes that are likely due to energy injection, which end at <IMG src='/wiley-blackwell_img/equation/MNR_17419_mu4.gif' alt ='inline image'/> and 7100 s, respectively. The decay slopes after the injection phases are consistent with each other (<IMG src='/wiley-blackwell_img/equation/MNR_17419_mu5.gif' alt ='inline image'/>). The X‐ray afterglow light curve appears to trace the optical, although the second energy‐injection phase was missed due to visibility constraints introduced by the <I>Swift</I> orbit. The X‐ray spectral index is <IMG src='/wiley-blackwell_img/equation/MNR_17419_mu6.gif' alt ='inline image'/> without temporal evolution. Its decay slope is consistent with the prediction of the forward shock model. Both X‐ray and optical emission are consistent with being in the same spectral regime above the cooling frequency (<IMG src='/wiley-blackwell_img/equation/MNR_17419_mu7.gif' alt ='inline image'/>). The fact that <IMG src='/wiley-blackwell_img/equation/MNR_17419_mu8.gif' alt ='inline image'/> is below the optical band from the very early epoch of the observation provides a constraint on the burst environment, which is similar to that seen in classical long‐duration GRBs. We therefore suggest that death of a massive star is the possible progenitor of this short burst.</P>
New light‐travel time models and orbital stability study of the proposed planetary system HU Aquarii
Hinse, T. C.,Lee, J. W.,Goź,dziewski, K.,Haghighipour, N.,Lee, C.‐,U.,Scullion, E. M. Blackwell Publishing Ltd 2012 Monthly notices of the Royal Astronomical Society Vol.420 No.4
<P><B>ABSTRACT</B></P><P>In this work we propose a new orbital architecture for the two proposed circumbinary planets around the polar eclipsing binary HU Aquarii. We base the new two‐planet, light‐travel time model on the result of a Monte Carlo simulation driving a least‐squares Levenberg–Marquardt minimization algorithm on the observed eclipse egress times. Our best‐fitting model with <IMG src='/wiley-blackwell_img/equation/MNR_20283_mu1.gif' alt ='inline image'/> resulted in high final eccentricities for the two companions leading to an unstable orbital configuration. From a large ensemble of initial guesses, we examined the distribution of final eccentricities and semimajor axes for different <IMG src='/wiley-blackwell_img/equation/MNR_20283_mu2.gif' alt ='inline image'/> parameter intervals and encountered qualitatively a second population of best‐fitting parameters. The main characteristic of this population is described by low‐eccentric orbits favouring long‐term orbital stability of the system. We present our best‐fitting model candidate for the proposed two‐planet system and demonstrate orbital stability over one million years using numerical integrations.</P>
Xiao, Fang,Li, Junhua,Singh, Anurag Kumar,Riederer, Brigitte,Wang, Jiang,Sultan, Ayesha,Park, Henry,Lee, Min Goo,Lamprecht, Georg,Scholte, Bob J.,De Jonge, Hugo R.,Seidler, Ursula Blackwell Publishing Ltd 2012 The Journal of physiology Vol.590 No.21
<P><B>Key points</B></P><P><P>Cystic fibrosis (CF) is a lethal disease characterized by low rates of epithelial Cl<SUP>−</SUP> and HCO<SUB>3</SUB><SUP>−</SUP> secretion and obstruction of the airways and gastrointestinal and reproductive organs by sticky mucus. HCO<SUB>3</SUB><SUP>−</SUP> secretion has recently been demonstrated to be necessary for mucus hydration.</P><P>The most frequent CF mutation is F508del. This mutant protein is usually degraded in the proteasome. New therapeutic strategies have been developed which deliver F508del to the plasma membrane.</P><P>Utilizing transgenic F508del mutant and cystic fibrosis transmembrane conductance regulator (CFTR) knockout mice, apical membrane expression of F508del protein was found to be associated with enhanced stimulation of intestinal HCO<SUB>3</SUB><SUP>−</SUP> secretion.</P><P>The predominant molecular mechanism for enhanced F508del HCO<SUB>3</SUB><SUP>−</SUP> stimulation appeared to be the activation of a Cl<SUP>−</SUP> recycling pathway, with Cl<SUP>−</SUP> exit via membrane‐resident F508del protein and Cl<SUP>−</SUP> entry in exchange for HCO<SUB>3</SUB><SUP>−</SUP> by apical Cl<SUP>−</SUP>/HCO<SUB>3</SUB><SUP>−</SUP> exchange. In contrast, the predominant molecular mechanism for cAMP‐activated HCO<SUB>3</SUB><SUP>−</SUP> secretion in WT intestine appears to be HCO<SUB>3</SUB><SUP>−</SUP> exit via CFTR itself.</P></P><P><B>Abstract </B> This study investigated whether expression of the common cystic fibrosis transmembrane conductance regulator (CFTR) mutant F508del in the apical membrane of enterocytes confers increased bicarbonate secretory capacity on the intestinal epithelium of F508del mutant mice compared to that of CFTR knockout (KO) mice. CFTR KO mice, F508del mutant mice (F508del) and wild‐type (WT) littermates were bred on the FVB/N background. F508del isolated brush border membrane (BBM) contained approximately 5–10% fully glycosylated band C protein compared to WT BBM. Similarly, the forskolin (FSK)‐induced, CFTR‐dependent short‐circuit current (Δ<I>I</I><SUB>sc</SUB>) of F508del mucosa was approximately 5–10% of WT, whereas the HCO<SUB>3</SUB><SUP>−</SUP> secretory response (<IMG src='/wiley-blackwell_img/equation/TJP_5291_mu1.gif' alt ='inline image'/>) was almost half that of WT in both duodenum and mid‐colon studied <I>in vitro</I> and <I>in vivo.</I> While WT intestine retained full FSK‐induced <IMG src='/wiley-blackwell_img/equation/TJP_5291_mu2.gif' alt ='inline image'/> in the absence of luminal Cl<SUP>−</SUP>, the markedly higher <IMG src='/wiley-blackwell_img/equation/TJP_5291_mu3.gif' alt ='inline image'/> than Δ<I>I</I><SUB>sc</SUB> in F508del intestine was dependent on the presence of luminal Cl<SUP>−</SUP>, and was blocked by CFTR inhibitors. The Ste20‐related proline–alanine‐rich kinases (SPAK/OSR1), which are downstream of the with‐no‐lysine (K) protein kinases (WNK), were rapidly phosphorylated by FSK in WT and F508del, but significantly more slowly in CFTR KO intestine. In conclusion, the data demonstrate that low levels of F508del membrane expression in the intestine of F508del mice significantly increased FSK‐induced HCO<SUB>3</SUB><SUP>−</SUP> secretion mediated by Cl<SUP>−</SUP>/HCO<SUB>3</SUB><SUP>−</SUP> exchange. However, in WT mucosa FSK elicited strong SPAK/OSR1 phosphorylation and Cl<SUP>−</SUP>‐independent HCO<SUB>3</SUB><SUP>−</SUP> efflux. This suggests that therapeutic strategies which deliver F508del to the apical membrane have the potential to significantly enhance epithelial HCO<SUB>3</SUB><SUP>−</SUP> secretion.</P>
Properties of the planetary caustic perturbation
Chung, Sun‐,Ju,Lee, Chung‐,Uk Blackwell Publishing Ltd 2011 Monthly notices of the Royal Astronomical Society Vol.411 No.1
<P><B>ABSTRACT</B></P><P>Just two of 10 extrasolar planets found by microlensing have been detected by the planetary caustic, despite the higher probability of planet detection relative to the central caustic, which has been responsible for four extrasolar planet detections. This is because the perturbations induced by the planetary caustic are unpredictable, thus making it difficult to carry out strategic observations. However, if future high‐cadence monitoring surveys are conducted, the majority of planetary caustic events including the events by free‐floating planets and wide‐separation planets would be detected. Hence, understanding the planetary caustic perturbations becomes important. In this paper, we investigate in detail the pattern of the planetary caustic perturbations. From this study, we find three properties of the planetary caustic perturbations. First, planetary systems with the same star–planet separation (<I>s</I>) basically produce perturbations of constant strength, regardless of the planet‐to‐star mass ratio (<I>q</I>), but the duration of each perturbation scales with <IMG src='/wiley-blackwell_img/equation/MNR_17664_mu1.gif' alt ='inline image'/>. Secondly, close planetary systems with the same separation produce essentially the same negative perturbations between two triangular‐shaped caustics, regardless of <I>q</I>, but the duration of the perturbations scales with <IMG src='/wiley-blackwell_img/equation/MNR_17664_mu2.gif' alt ='inline image'/>. Thirdly, the positive perturbations for planetary systems with the same mass ratio become stronger as the caustic shrinks with the increasing |log <I>s</I>|, while the negative perturbations become weaker. We estimate the degeneracy in the determination of <I>q</I> that occurs in planetary caustic events. From this, we find that the mass ratio can be more precisely determined as <I>q</I> increases and |log <I>s</I>| decreases. We also find that the degeneracy range of events for which the source star passes close to the planetary caustic is usually very narrow, and thus it would not significantly affect the determination of <I>q</I>.</P>
A fraction of deep vascular birthmarks are true deep hemangiomas of infancy
Lee, Seok-Jong,Shin, Dong Ju,Kim, Ho Youn,Lee, Weon Ju,Kim, Do Won,Chung, Ho Yun,Baik, Seung Kug,Lee, Jong Min,Huh, Seung,Yoon, Ghil Suk Blackwell Publishing Ltd 2009 International journal of dermatology Vol.48 No.8
<P>Abstract</P><P>Background </P><P>Deeply-located vascular birthmarks have been traditionally regarded as being identical to a deep type of hemangioma of infancy (HOI). However, there is increasing evidence that some venous malformations also mimic these deep type of HOIs clinically. This study investigates how many, if not all, deep vascular birthmarks are deep type HOIs.</P><P>Methods </P><P>Nineteen cases were selected on the basis of the clinical features of deeply-located vascular birthmarks. Hematoxylin-eosin slides were reviewed and immunohistochemistries were performed using CD31, D2-40 and GLUT1 to confirm diagnoses before they were compared with the clinicoradiologic review by specialists other than dermatopathologists.</P><P>Results </P><P>Only 4 patients out of a total of 19 cases were strongly positive for GLUT1 staining and turned out to be true deep HOIs. The remaining were comprised of 6 venous malformations (31.6%), 3 lymphatic malformations (15.8%), 1 glomangioma (5.3%) and 5 tufted angiomas (26.3%).</P><P>Conclusion </P><P>It was demonstrated that all deeply-located vascular birthmarks are not true deep HOIs. It is recommended that diagnosis for HOI be carried out cautiously earlier in life using GLUT1 in addition to clinical features. This would help prevent patients from being misled by anticipating the spontaneous involution in all deeply-located vascular birthmarks.</P>
Kim, H. C.,Kim, H. J.,Lee, C. J.,Kim, B. M.,Park, J. K.,Versluis, A. Blackwell Publishing Ltd 2009 International endodontic journal Vol.42 No.7
<P>Abstract</P><P>Aim </P><P>To evaluate how different cross-sectional designs affect stress distribution in nickel–titanium (NiTi) instruments during bending, torsion and simulated shaping of a curved canal.</P><P>Methodology </P><P>Four NiTi rotary instruments with different cross-sectional geometries were selected: ProFile and HeroShaper systems with a common triangle-based cross section, Mtwo with an S-shaped rectangle-based design and NRT with a modified rectangle-based design. The geometries of the selected files were scanned in a micro-CT and three-dimensional finite-element models were created for each system. Stiffness characteristics for each file system were determined in a series of bending and torsional conditions. Canal shaping was simulated by inserting models of the rotating file into a 45° curved canal model. Stress distribution in the instruments was recorded during simulated shaping. After the instruments were retracted from the canal, residual stresses and permanent bending of their tips due to plastic deformation were determined.</P><P>Results </P><P>The greatest bending and torsional stiffness occurred in the NRT file. During simulated shaping, the instruments with triangle-based cross-sectional geometry had more even stress distributions along their length and had lower stress concentrations than the instruments with rectangle-based cross sections. Higher residual stresses and plastic deformations were found in the Mtwo and NRT with rectangle-based cross-sectional geometries.</P><P>Conclusions </P><P>Nickel–titanium instruments with rectangle-based cross-sectional designs created higher stress differentials during simulated canal shaping and may encounter higher residual stress and plastic deformation than instruments with triangle-based cross sections.</P>
Kim, Woon Ryoung,Park, Ok-hee,Choi, Sukwoo,Choi, Se-Young,Park, Soon Kwon,Lee, Kea Joo,Rhyu, Im Joo,Kim, Hyun,Lee, Yeon Kyung,Kim, Hyun Taek,Oppenheim, Ronald W.,Sun, Woong Blackwell Publishing Ltd 2009 The European journal of neuroscience Vol.29 No.7
<P>Abstract</P><P>A considerable number of new neurons are generated daily in the dentate gyrus (DG) of the adult hippocampus, but only a subset of these survive, as many adult-generated neurons undergo programmed cell death (PCD). However, the significance of PCD in the adult brain for the functionality of DG circuits is not known. Here, we examined the electrophysiological and behavioral characteristics of <I>Bax</I>-knockout (<I>Bax</I>-KO) mice in which PCD of post-mitotic neurons is prevented. The continuous increase in DG cell numbers in <I>Bax</I>-KO mice resulted in the readjustment of afferent and efferent synaptic connections, represented by age-dependent reductions in the dendritic arborization of DG neurons and in the synaptic contact ratio of mossy fibers with CA3 dendritic spines. These neuroanatomical changes were associated with reductions in synaptic transmission and reduced performance in a contextual fear memory task in 6-month-old <I>Bax</I>-KO mice. These results suggest that the elimination of excess DG neurons via <I>Bax</I>-dependent PCD in the adult brain is required for the normal organization and function of the hippocampus.</P>
Kim, C. H.,Park, J. Y.,Park, M. K.,Kang, E. J.,Kim, J. H. Blackwell Publishing Ltd 2008 Journal of applied ichthyology Vol.24 No.3
<P>Summary</P><P>The morphology and distribution of the minute tubercles on the skin surface of larvae in Korean bitterling, <I>Rhodeus pseudosericeus,</I> were observed during larval development. Just after hatching, the epidermis of the larvae consists of a thin single cell layer having smaller basophilic flat or round-flattened basal cells. As the larvae grow, the epidermis contains more small flat cells and large epidermal cells that are round or hemisphere-shaped. These large unicellular epidermal cells, called minute tubercles, consist of more or less homogeneous cytoplasm that is PAS (Periodic acid-Schiff method) positive. They are more densely distributed in the wing-like yolk sac projection. Vestigial minute tubercles occur in the body region and the caudal fin-fold region. These minute tubercles grow in number and height from 6 to 8 days after hatching onward. However, they become reduced in height and number as the larvae develop. At day 31 after hatching (i.e. free-swimming stage), minute tubercles no longer exist on the larval skin. The sequence of occurrence and gradual disappearance of these cell structures are described and histologically documented for comparative purposes of beta, taxnomomic and environmental studies.</P>
Kim, Tae-Gyun,Wikesjö,, Ulf M. E.,Cho, Kyoo-Sung,Chai, Jung-Kiu,Pippig, Susanne D.,Siedler, Michael,Kim, Chong-Kwan Blackwell Publishing Ltd 2009 Journal of Clinical Periodontology Vol.36 No.7
<P>Abstract</P><P>Aim</P><P>Recombinant human growth/differentiation factor-5 (rhGDF-5) is being evaluated as a candidate therapy in support of periodontal regeneration. The objective of this study was to evaluate cementum and alveolar bone formation, and aberrant healing events following surgical implantation of rhGDF-5 in an absorbable collagen sponge (ACS) carrier using an established periodontal defect model.</P><P>Materials and Methods</P><P>Bilateral 4 × 5 mm (width × depth), one-wall, critical-size, intrabony periodontal defects were surgically created at the mandibular second and fourth pre-molar teeth in 15 Beagle dogs. Five animals received 1 <I>μ</I>g/defect and five animals 20 <I>μ</I>g/defect rhGDF-5 in unilateral defect sites. Contralateral sites received treatments reported elsewhere. Five animals received rhGDF-5/ACS with 0 (buffer control) and 100 <I>μ</I>g/defect rhGDF-5 in contralateral defect sites. The animals were euthanized at 8 weeks post-surgery for histologic and histometric evaluation.</P><P>Results</P><P>Surgical implantation of rhGDF-5 stimulated significant periodontal regeneration. Cementum formation was significantly enhanced in sites implanted with rhGDF-5 (1 and 100 <I>μ</I>g) compared with control (<I>p</I><0.05). Similarly, bone formation height was significantly greater in sites receiving rhGDF-5 (1 and 100 <I>μ</I>g) compared with control (<I>p</I><0.05). There were no significant or remarkable differences in bone and cementum formation within the selected dose interval (1, 20 and 100 <I>μ</I>g rhGDF-5). None of the control or the rhGDF-5 sites exhibited root resorption, ankylosis, or other aberrant tissue reactions.</P><P>Conclusion</P><P>Surgical implantation of rhGDF-5/ACS may be used safely to support periodontal wound healing/regeneration in intrabony periodontal defects without complications.</P>