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>

Rescue of epithelial HCO₃⁻ secretion in murine intestine by apical membrane expression of the cystic fibrosis transmembrane conductance regulator mutant F508del

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>

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>

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>

β‐Catenin regulates melanocyte dendricity through the modulation of PKCζ and PKCδ

Kim, Jin‐,Hwa,Sohn, Kyung‐,Cheol,Choi, Tae‐,Young,Kim, Mi Yoon,Ando, Hideya,Choi, Sun Ja,Kim, Sooil,Lee, Young Ho,Lee, Jeung‐,Hoon,Kim, Chang Deok,Yoon, Tae‐,Jin Blackwell Publishing Ltd 2010 Pigment cell & melanoma research Vol.23 No.3

<P><B>Summary</B></P><P>The Wnt/β‐catenin signaling pathway is involved in the melanocyte differentiation and melanoma development. However, the effect of β‐catenin for dendrite formation has not been clearly elucidated yet in normal human epidermal melanocytes (NHEM). To investigate the effect of β‐catenin, we transduced NHEM with recombinant adenovirus expressing β‐catenin. Forced expression of β‐catenin led to the dramatic morphological changes of NHEM, including the reduction of dendrite length and enlargement of cell body. Concomitantly with, the protein levels for dendrite formation‐related molecules, such as Rac1 and Cdc42, were markedly decreased. In addition, phosphorylation of p38 MAPK was significantly reduced by β‐catenin, potentiating its inhibitory role for dendrite formation. Interestingly, overexpression of β‐catenin led to the increase of protein kinase C ζ (PKCζ) level, while protein kinase C δ (PKCδ) was decreased by β‐catenin, suggesting that those PKCs were β‐catenin‐downstream modulators in NHMC. When PKCζ was overexpressed, dendrites were shortened, with the reduced protein levels for Rac1 and Cdc42. In contrast, PKCδ overexpression led to the elongation of dendrites, with the increased levels for Rac1 and Cdc42. These results suggest that β‐catenin play an inhibitory role for dendrite formation through the modulation of PKCζ and PKCδ.</P>

Epidemiological Characteristics of the 2002 Outbreak of Foot-and-Mouth Disease in The Republic of Korea

Wee, S.-H.,Yoon, H.,More, S. J.,Nam, H.-M.,Moon, O.-K.,Jung, J.-M.,Kim, S.-J.,Kim, C.-H.,Lee, E.-S.,Park, C.-K.,Hwang, I.-J. Blackwell Publishing Ltd 2008 Transboundary and emerging diseases Vol.55 No.8

<P>Summary</P><P>The Republic of Korea experienced a foot-and-mouth disease (FMD) outbreak during May–June 2002. The present study describes epidemiological characteristics of the 2002 FMD outbreak in Korea, including the pattern of the outbreak in both time and space, transmission routes among infected farms, and control measures. One of the notable features of the 2002 FMD epidemic in Korea was that the virus infected mostly pigs [15 of 16 infected premises (IPs)], despite the presence of other susceptible animals on infected and neighbouring farms. The epidemic showed temporal clustering at 8–9 day intervals, suggesting five generations of infection during the outbreak, and 13 of 16 (81.3%) IPs were located within a 10 km-radius of the index case. The clinical signs that prompted notification of infection included vesicles around hooves and snouts. The age of lesions was significantly less among cases reported by farmers compared with veterinarians. The high awareness of farmers from an earlier FMD outbreak greatly helped the animal hygiene authority in efforts associated with disease control and eradication. The outbreak was eradicated within < 2 months as a result of the intensive control efforts of the animal hygiene authorities and the cooperation of the Korean people. Although the outbreak was a costly lesson for the Korean people, the experience gained will contribute to future efforts in the prevention and control of animal infectious diseases.</P>

Keratinocytes in culture accumulate phagocytosed melanosomes in the perinuclear area

Ando, Hideya,Niki, Yoko,Yoshida, Masaki,Ito, Masaaki,Akiyama, Kaoru,Kim, Jin‐,Hwa,Yoon, Tae‐,Jin,Lee, Jeung‐,Hoon,Matsui, Mary S.,Ichihashi, Masamitsu Blackwell Publishing Ltd 2010 Pigment cell & melanoma research Vol.23 No.1

<P><B>Summary</B></P><P>There are many techniques for evaluating melanosome transfer to keratinocytes but the spectrophotometric quantification of melanosomes incorporated by keratinocyte phagocytosis has not been previously reported. Here we describe a new method that allows the spectrophotometric visualization of melanosome uptake by normal human keratinocytes in culture. Fontana‐Masson staining of keratinocytes incubated with isolated melanosomes showed the accumulation of incorporated melanosomes in the perinuclear areas of keratinocytes within 48 h. Electron microscopic observations of melanosomes ingested by keratinocytes revealed that many phagosomes containing clusters of melanosomes or their fragments were localized in the perinuclear area. A known inhibitor of keratinocyte phagocytosis which inhibits protease‐activated receptor‐2, i.e., soybean trypsin inhibitor, decreased melanosome uptake by keratinocytes in a dose‐dependent manner. These data suggest that our method is a useful model to quantitate keratinocyte phagocytosis of melanosomes visually in vitro.</P>

Contrasting levels of genetic diversity between the historically rare orchid <i>Cypripedium japonicum</i> and the historically common orchid <i>Cypripedium macranthos</i> in South Korea

CHUNG, JAE MIN,PARK, KWANG WOO,PARK, CHONG-SEO,LEE, SUNG-HO,CHUNG, MYONG GI,CHUNG, MI YOON Blackwell Publishing Ltd 2009 Botanical journal of the Linnean Society Vol.160 No.2

<P>Many terrestrial orchids are historically rare and occur in small, spatially isolated populations. Theory predicts that such species will harbour low levels of genetic variation within populations and will exhibit a high degree of population genetic divergence, primarily as a result of genetic drift. If the origin of the present-day populations is relatively recent from the same genetically depauperate source population, a complete lack of genetic differentiation between conspecific populations is expected. If a terrestrial orchid was historically common with moderate or high levels of genetic diversity, but has experienced more recent anthropogenic disturbance as a result of over-collection, it would still exhibit initial levels of genetic variation within populations and a low degree of genetic divergence between populations. To test these predictions, we examined the genetic diversity in six populations (<I>N</I> = 131) of the historically and currently rare <I>Cypripedium japonicum</I> and in four populations (<I>N</I> = 94) of the historically common but now rare <I>C. macranthos</I> from South Korea. Fourteen putative allozyme loci resolved from eight enzyme systems revealed no variation either within or among populations of <I>C. japonicum</I>, which supports the first prediction. In contrast, populations of <I>C. macranthos</I> harboured high levels of genetic variation (mean percentage of polymorphic loci %<I>P</I> = 46.7; mean expected heterozygosity <I>H</I><SUB>e</SUB> = 0.185) and exhibited a low degree of population genetic divergence (<I>G</I><SUB>ST</SUB> = 0.059), supporting the second prediction. The lack of genetic variation both within and among conspecific populations of <I>C. japonicum</I> may suggest that populations originated from the same genetically depauperate ancestral population. The high levels of genetic diversity maintained in populations of <I>C. macranthos</I> suggest that the collection-mediated decrease in the number of individuals is still too recent for long-term effects on genetic variation. Based on current demographic and genetic data, <I>in situ</I> and <I>ex situ</I> conservation strategies should be provided to preserve genetic variation and to ensure the long-term survival of the two species in the Korean Peninsula. © 2009 The Linnean Society of London, <I>Botanical Journal of the Linnean Society</I>, 2009, <B>160</B>, 119–129.</P>

PHYLOGENETIC RELATIONSHIPS WITHIN THE GENUS <i>HYPNEA</i> (GIGARTINALES, RHODOPHYTA), WITH A DESCRIPTION OF <i>H. CAESPITOSA</i> SP. NOV.¹

Geraldino, Paul John L.,Riosmena-Rodriguez, Rafael,Liao, Lawrence M.,Boo, and Sung Min Blackwell Publishing Ltd 2010 Journal of phycology Vol.46 No.2

<P>Species discrimination within the gigartinalean red algal genus <I>Hypnea</I> has been controversial. To help resolve the controversy and explore phylogeny within the genus, we determined <I>rbc</I>L sequences from 30 specimens of 23 species within the genus, <I>cox</I>1 from 22 specimens of 10 species, and <I>psa</I>A from 16 species. We describe <I>H. caespitosa</I> as a new species characterized by a relatively slender main axis; a pulvinate growth habit with entangled, anastomosing, and subulate uppermost branches; and unilaterally borne tetrasporangial sori. The new species occurs in the warm waters of Malaysia, the Philippines, and Singapore. The phylogenetic trees of <I>rbc</I>L, <I>psa</I>A, and <I>cox</I>1 sequences showed a distant relationship of <I>H. caespitosa</I> to <I>H. pannosa</I> J. Agardh from Baja California and the marked differentiation from other similar species. The <I>rbc</I>L + <I>psa</I>A tree supported monophyly of the genus with high bootstrap values and posterior probabilities. The analysis revealed three clades within the genus, corresponding to three sections, namely, <I>Virgatae</I>, <I>Spinuligerae</I>, and <I>Pulvinatae</I> first recognized by J. G. Agardh. Exceptions were <I>H. japonica</I> T. Tanaka in <I>Pulvinatae</I> and <I>H. spinella</I> (C. Agardh) Kütz. in <I>Spinuligerae.</I></P>

Enumeration, isolation and identification of diazotrophs from Korean wetland rice varieties grown with long-term application of N and compost and their short-term inoculation effect on rice plants

Muthukumarasamy, R.,Kang, U.G.,Park, K.D.,Jeon, W.-T.,Park, C.Y.,Cho, Y.S.,Kwon, S.-W.,Song, J.,Roh, D.-H.,Revathi, G. Blackwell Publishing Ltd 2007 Journal of applied microbiology Vol.102 No.4

<P>Abstract</P><P>Aim: </P><P>This study has been aimed (i) to isolate and identify diazotrophs from Korean rice varieties; (ii) to examine the long-term effect of N and compost on the population dynamics of diazotrophs and (iii) to realize the shot-term inoculation effect of these diazotrophs on rice seedlings.</P><P>Methods and Results: </P><P>Diazotrophic and heterotrophic bacterial numbers were enumerated by most probable number method and the isolates were identified based on morphological, physiological, biochemical and 16s rDNA sequence analysis. Long-term application of fertilizer N with compost enhanced both these numbers in rice plants and its environment. Bacteria were high in numbers when malate and azelaic acids were used as carbon source, but less when sucrose was used as a carbon substrate. The combined application promoted the association of diazotrophic bacteria like <I>Azospirillum</I> spp., <I>Herbaspirillum</I> spp., <I>Burkholderia</I> spp., <I>Gluconacetobacter diazotrophicus</I> and <I>Pseudomonas</I> spp. in wetland rice plants. Detection of <I>nif</I>D genes from different diazotrophic isolates indicated their nitrogen fixing ability. Inoculation of a representative isolate from each group onto rice seedlings of the variety IR 36 grown in test tubes indicated the positive effect of these diazotrophs on the growth of rice seedlings though the percentage of N present in the plants did not differ much.</P><P>Conclusions: </P><P>Application of compost with fertilizer N promoted the diazotrophic and heterotrophic bacterial numbers and their association with wetland rice and its environment. Compost application in high N fertilized fields would avert the reduction of N<SUB>2</SUB>-fixing bacterial numbers and their association was beneficial to the growth of rice plants.</P><P>Significance and Impact of the Study: </P><P>The inhibitory effect of high N fertilization on diazotrophic bacterial numbers could be reduced by the application of compost and this observation would encourage more usage of organic manure. This study has also thrown light on the wider geographic distribution of <I>G. diazotrophicus</I> with wetland rice in temperate region where sugarcane (from which this bacterium was first reported to be associating and thereon from other plant species) is not cultivated.</P>