1,880 research outputs found

    Tau functions as Widom constants

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    We define a tau function for a generic Riemann-Hilbert problem posed on a union of non-intersecting smooth closed curves with jump matrices analytic in their neighborhood. The tau function depends on parameters of the jumps and is expressed as the Fredholm determinant of an integral operator with block integrable kernel constructed in terms of elementary parametrices. Its logarithmic derivatives with respect to parameters are given by contour integrals involving these parametrices and the solution of the Riemann-Hilbert problem. In the case of one circle, the tau function coincides with Widom's determinant arising in the asymptotics of block Toeplitz matrices. Our construction gives the Jimbo-Miwa-Ueno tau function for Riemann-Hilbert problems of isomonodromic origin (Painlev\'e VI, V, III, Garnier system, etc) and the Sato-Segal-Wilson tau function for integrable hierarchies such as Gelfand-Dickey and Drinfeld-Sokolov.Comment: 26 pages, 6 figure

    Nitrogen Use Efficiency of Late Fall-Applied Urea and Pig Slurry for Regrowth of Perennial Ryegrass Sward

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    Pig slurry is the most important organic resource in Korea, as estimated to be more than 15% of recycled animal manure. The use of pig slurry as an alternative organic fertilizer is the most viable recycling option as it is produced in large amount on pig farms that has usually less or not surface for cultivation of forage crops in Korea. Perennial grasses in grassland system regrow successively after harvests by cutting or grazing. The regrowth yield at each harvest would be a crucial determinant for the productivity of sward. During vegetative regrowth, soil mineral N and N reserves meet the N requirements for shoot regrowth. The aims of this study are to estimate the N use efficiency of urea and pig slurry applied at late fall in relation to the N availability for restoring organic reserves and constructing ultimate regrowth biomass during successive three cycle of regrowth of perennial ryegrass sward

    Reconstructive challenge of dermatofibrosarcoma protuberans in the female breast

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    Dermatofibrosarcoma protuberans is an uncommon locally aggressive malignant neoplasm that most frequently appears in the trunk, followed by the extremities, head, and neck. But occurrence in the breast is extremely rare. We present a case of a 28-year-old woman, who had a history of trauma 5 years previously and excision 1 year before presentation at our clinic. We performed wide excision, together with microscopic and immunohistochemical analysis. No postoperative oncologic treatment was used and she remains disease-free 1 year after the surgery without any tumor recurrence. Here, we report a case of dermatofibrosarcoma protuberans in the female breast and present a detailed discussion of the diagnosis and treatment with reference to available literatures

    S Nutrition Is Involved in Alleviation of Damage of Photosynthetic Organelles by Salt Stress in Kentucky Bluegrass (\u3cem\u3ePoa pratensis\u3c/em\u3e L.)

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    Salt-stress is considered as one of the major environmental factor limiting plant growth and productivity. It has been well reported that salt stress induce the reduction of stomatal density and number leading to poor gaseous exchange which resulted in decrease of photosynthesis is associated with inhibition of several enzymes related to the Calvin cycle such as RuBisCo. In addition, salt stress decreases photosynthetic pigments such as chlorophyll and carotenoid which has important role in photosynthesis. Sulfur (S) is one of six macronutrients needed for proper plant growth and development. In our previous work, we found that sulfur nutrition has significant role in ameliorating the damaged in photosynthetic organelles caused by Fe-deficiency in oilseed rape (Muneer et al., 2014). In addition, application of sulfur mitigated the adverse effects of heavy metals stress by enhancing plant growth, chlorophyll content and net photosynthetic rate. Despite extensive researches attempting to elucidate the interactions between external sulfur supplies and stress tolerance, to our knowledge, the responses of the photosynthetic mechanism to combined S deficiency and salt stress have not yet been fully investigated. In this study, therefore, we hypothesized that S nutrition affects photosynthetic organs to salt stress, so that may involve in alleviating negative impact of salt stress in Kentucky bluegrass. To test this hypothesis, the responses of photosynthetic parameters, thylakoid protein complexes and ion uptake were compared for 21 days of four S and salt stress combined treatments; sulfur sufficient without salt stress (+S/non-salt, control), present of sulfur with salt stress (+S/salt), sulfur deprivation without salt stress (-S/non-salt) and sulfur deprivation and salt stress (-S/salt)

    Orphan nuclear receptor Nurr1 induces neuron differentiation from embryonic cortical precursor cells via an extrinsic paracrine mechanism

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    AbstractNurr1 is an orphan nuclear receptor-type transcription factor (TF) that plays critical roles in midbrain dopamine neuron development. This study demonstrated a novel role for Nurr1 in neuronal/astrocytic differentiation of neural precursor (NP) cells isolated from rat embryonic cortices: overexpression of this TF promoted NP cell differentiation towards neurons at the expense of astrocytic differentiation. Single cell-based lineage analyses and experiments using co-cultures revealed that Nurr1 elicited its neurogenic role in an extrinsic paracrine manner. We defined diffusible factors and downstream neurogenic TFs responsible for the Nurr1-mediated neuronal differentiation

    Comparative Sulfur Use Efficiency and Water Stress Tolerance in Two \u3cem\u3eBrassica napus\u3c/em\u3e Cultivars

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    S-deficiency and/or S-deprivation decreases the cell sap osmotic potential resulting from a net increase of intracellular solutes rather than from a loss of cell water and chlorophyll content resulting in a restriction of Rubisco synthesis and provoked the chlorosis of young leaves (Lee et al., 2014; Muneer et al., 2014). These imply that S-deficiency results in a general inhibition of photosynthesis and protein synthesis. On the other hand, several studies have indicated that S nutrition has a potential role in stress tolerance and defense mechanism. Sulfur is an essential element in the formation of sulfhydryl (S-H) and disulphide bond (S-S). These bonds are important for the stabilization of protein structures. In this context, the roles of S nutrition in alleviating negative responses to salinity stress (Fatma et al., 2014) and iron deficiency (Muneer et al., 2014) have been widely reported. In this study, we hypothesized that cultivar variation in sulfur use efficiency (SUE) under Polyethylene glycol (PEG)-induced water stress may be attributed to S-uptake efficiency (SUpE; S uptake per S supplied), and that the genotype having higher SUE is more tolerant to PEG-induced water stress. To test this hypothesis, direct quantifications of S uptake was done by a 34S tracing method. The responses of photosynthetic activity-related parameters to PEG-induced water stress were also assessed in relation to SUE in two B. napus cultivars

    Tetraploid embryo aggregation produces high-quality blastocysts with an increased trophectoderm in pigs

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    Tetraploid complementation is an ideal method for demonstrating the differentiation potential of pluripotent stem cells. In this study, we selected the most efficient tetraploid production method for porcine embryos and investigated whether tetraploid blastomere aggregation could enhance the quality of tetraploid embryos. Three methods were investigated to produce tetraploid embryos: First, tetraploid embryos were produced using electro-fusion of two-cell stage parthenogenetic blastomere (FUTP). Second, somatic cell was injected into the mature oocyte and fused to produce tetraploid embryos. Third, oocytes were matured with Cytochalasin B (CB) for the late 22Ā h of in vitro maturation to inhibit the first polar body (PB1). Following that, non-PB1 oocytes were treated with CB for 4Ā h after parthenogenetic activation. There was no significant difference in the blastocyst development rate and tetraploid production rate of the embryos produced through the three methods. However, FUTP-derived blastocysts had a significantly lower percentage of apoptotic cells compared to other methods. The developmental competence of embryos, expression of trophectoderm cell marker genes, and distribution of YAP1 protein were investigated in tetraploid embryos produced using the FUTP method. The FUTP method most effectively prevented apoptosis during porcine tetraploid embryo formation. Tetraploid aggregation-derived blastocysts have a high proportion of trophectoderm with increased expression of the CDX2 mRNA and high YAP1 intensity. High-quality blastocysts derived from a tetraploid embryo aggregation can serve as suitable source material for testing the differentiation potential of pluripotent stem cells for blastocyst complementation in pigs

    Double Glomus Tumors Originating in the Submandibular and Parotid Regions

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    Glomus tumors are rare neoplasms that originate from the glomus bodies, an arteriovenous anastomosis with a specialized vascular structure. The most common site for these tumors is the subungal region of the fingers. Occasionally, glomus tumors are found in the middle ear, trachea, nasal cavities, stomach, and lungs. The occurrence in the parotid regions is very rare. While multiple glomus tumors in the whole body are thought to represent only 10% of all cases, instances of multiple tumors in the neck have not yet been reported in the literature. We report a case of double glomus tumors in the submandibular and parotid regions
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