Is the late near-infrared bump in short-hard GRB 130603B due to the Li-Paczynski kilonova?

Short-hard gamma-ray bursts (GRBs) are widely believed to be produced by the merger of two binary compact objects, specifically by two neutron stars or by a neutron star orbiting a black hole. According to the Li-Paczynski kilonova model, the merger would launch sub-relativistic ejecta and a near-infrared/optical transient would then occur, lasting up to days, which is powered by the radioactive decay of heavy elements synthesized in the ejecta. The detection of a late bump using the {\em Hubble Space Telescope} ({\em HST}) in the near-infrared afterglow light curve of the short-hard GRB 130603B is indeed consistent with such a model. However, as shown in this Letter, the limited {\em HST} near-infrared lightcurve behavior can also be interpreted as the synchrotron radiation of the external shock driven by a wide mildly relativistic outflow. In such a scenario, the radio emission is expected to peak with a flux of $\sim 100 \mu$Jy, which is detectable for current radio arrays. Hence, the radio afterglow data can provide complementary evidence on the nature of the bump in GRB 130603B. It is worth noting that good spectroscopy during the bump phase in short-hard bursts can test validity of either model above, analogous to spectroscopy of broad-lined Type Ic supernova in long-soft GRBs.Comment: 4 pages, 2 figures, published in ApJ Lette

A supra-massive magnetar central engine for short GRB 130603B

We show that the peculiar early optical and in particular X-ray afterglow emission of the short duration burst GRB 130603B can be explained by continuous energy injection into the blastwave from a supra-massive magnetar central engine. The observed energetics and temporal/spectral properties of the late infrared bump (i.e., the "kilonova") are also found consistent with emission from the ejecta launched during an NS-NS merger and powered by a magnetar central engine. The isotropic-equivalent kinetic energies of both the GRB blastwave and the kilonova are about $E_{\rm k}\sim 10^{51}$ erg, consistent with being powered by a near-isotropic magnetar wind. However, this relatively small value demands that most of the initial rotational energy of the magnetar $(\sim {\rm a~ few \times 10^{52}~ erg})$ is carried away by gravitational wave radiation. Our results suggest that (i) the progenitor of GRB 130603B would be a NS-NS binary system, whose merger product would be a supra-massive neutron star that lasted for about $\sim 1000$ seconds; (ii) the equation-of-state of nuclear matter would be stiff enough to allow survival of a long-lived supra-massive neutron star, so that it is promising to detect bright electromagnetic counterparts of gravitational wave triggers without short GRB associations in the upcoming Advanced LIGO/Virgo era.Comment: Five pages including 1 Figure, to appear in ApJ

3-Benzyl­amino-2-cyano-N-[N-(2-fluoro­phenyl)­carbamo­yl]-3-(methyl­sulfanyl)acryl­amide

In the crystal structure of the title compound, C19H17FN4O2S, mol­ecules are linked via pairs of N—H⋯N inter­actions, forming centrosymmetric dimers. Two intra­molecular N—H⋯O hydrogen bonds stabilize the mol­ecular conformation

Inhibitory effects of total saponins from Ilex pubescens Hook against hydrogen peroxide-induced cardiomyocyte apoptosis

Purpose: To study the protective effects of total saponins from Ilex pubescens Hook (IPTS) against cardiomyocyte apoptosis.Methods: Response surface methodology (RSM) based on Box-Benhnken Design (BBD) was carried out to optimize the extraction of IPTS. Thereafter, H9c2 cell model prepared by hydrogen peroxide (H2O2) treatment was used to investigate the effects of IPTS on cardiomyocyte apoptosis. Cell viability was determined using MTT assay, while the levels of lactate dehydrogenase (LDH), malondialdehyde (MDA), superoxide dismutase (SOD), creatine kinase (CK) and catalase (CAT) were measured as indices of oxidative stress. Expressions of proteins related to apoptosis (caspase-3, Bax and Bcl-2) were measured using Western blot assay.Results: Optimal IPTS extraction was achieved with extraction temperature of 86.6 °C, extraction time of 2.23 h and water: raw material ratio of 10.8 mL/g. IPTS extract, at doses of 200, 400, 600 and 800 μg/mL, significantly increased the viability of H2O2-treated H9c2 cells (p < 0.05), but significantly decreased LDH and CK activities (p < 0.01). It also led to significant increases in SOD and CAT activities, and significant decreases in the levels of MDA in these cells (p < 0.01). There were significant down-regulation of the protein expressions of caspase-3 and Bax (p < 0.01) in IPTS-treated H9c2 cells, as well as significant up-regulation of Bcl-2 protein expression (p < 0.01).Conclusion: These results suggest that IPTS can protect cardiomyocytes against apoptosis via the inhibition of oxidative stress and mitochondria-induced intrinsic apoptosis.Keywords: Ilex pubescens, Total saponins, Cardiomyocytes, Apoptosis, H9c2 cell

Pseudomonas aeruginosa ecthyma gangrenosum in a woman with recurrent Graves’ disease

SummaryA 35-year-old woman with postoperative recurrent Graves’ disease presented with a 5-day history of a red swelling on the right cheek associated with 4 days of remittent hyperpyrexia. Investigations revealed fever, a gangrenous ulcer on the right cheek, submandibular lymphadenopathy, and thyroid gland enlargement. Her white blood cell count, immunoglobulins, and lymphocyte subsets were unremarkable. Thyroid function tests showed low thyroid-stimulating hormone, high free thyroxine, and elevated radioactive iodine uptake. Repeated pus cultures grew Pseudomonas aeruginosa, but blood cultures were negative. An ill-demarcated erythematous plaque occurred on the right leg on hospital day 3. She was treated with intravenous antibiotics with topical gentamicin, recombinant bovine basic fibroblast growth factor, and radioiodine therapy with anti-thyroid drugs. The ulcer healed leaving a depressed scar at 35 days after discharge. This patient may represent the first case of P. aeruginosa ecthyma gangrenosum and cellulitis in postoperative recurrent Graves’ disease

A selected pre-amplification strategy for genetic analysis using limited DNA targets

Background: Limited DNA resources or limited DNA targets in predominant backgrounds for genetic tests can lead to misdiagnosis. We developed a strategy to selectively increase the amount of minor targets through a specific pre-amplification procedure. Methods: We used the model of circulating cell free (ccf) male fetal DNA as a minor target in the predominant maternal plasma DNA to evaluate the strategy. The sex determining region (SRY) locus on the Y chromosome was used to identify ccf fetal DNA, and the human glyceraldehydes-3-phosphate dehydrogenase (GAPDH) gene was used to identify ccf total DNA in maternal plasma. We selectively pre-amplified the minor target SRY locus using the Expand Long Template PCR system and assessed the efficiency of the pre-amplification by real-time PCR, for both SRY and GAPDH, to compare the quantities of pre-amplified fetal DNA with those of maternal total DNA without pre-amplification. Results: The selected pre-amplification increased the amount of ccf fetal DNA dramatically (Wilcoxon test: p=0.000, the fold change=11,596). After selected pre-amplification, a proportion of 2.19% of the ccf fetal minor part in the predominant maternal component was changed up to 25,334%. The increased amounts of ccf fetal DNA found with the pre-amplification are not correlated to the amounts found without the procedure (r=−0.017, p=0.949). Conclusions: This strategy may be useful in genetic analysis with limited DNA resources and limited DNA targets in predominant background molecules. However, this approach is not suitable for quantitative assessments, due to the fact that quantitative imbalanced amplification was observed as a result of the pre-amplification procedure. Clin Chem Lab Med 2009;47:288-9

The spectrum of Gamma-ray Burst: a clue

In this work we numerically calculate the thermal radiation efficiency of the baryonic outflow. The possible outflow acceleration in the transparent stage, which lowers thermal radiation efficiency, has been taken into account. In the standard internal shock model for the prompt emission, the fast shells should move with a typical Lorentz factor $\gtrsim 5 \Gamma_{\rm i}$ otherwise the GRB efficiency will be in disagreement with the observations, where $\Gamma_{\rm i}$ is the bulk Lorentz factor of the shocked/emitting region. The photosphere radius of these fast shells is small and the thermal radiation is too strong to be effectively outshone by the internal shock emission. This is particularly the case for some extremely bright events having $\Gamma_{\rm i} \sim 10^{3}$, like GRBs 080319B and 080916C. The absence of a distinct thermal component in the spectrum of most GRBs challenges the standard internal shock model and may suggest a non-baryonic (magnetic) outflow component. Though the magnetic outflow model seems favored by more and more data, it can hardly reproduce the typical GRB spectrum. In the photosphere-gradual magnetic dissipation scenario, the spectrum cuts off at $\sim 1$ GeV, too low to account for the observations of GRBs 080916C. In the sudden magnetic energy dissipation model, the low energy spectrum is expected to be $F_\nu \propto \nu^{-1/2}$, too soft to be consistent with the data $F_\nu \propto \nu^{0}$. We speculate that the low energy spectrum puzzle could be unveiled by the mechanism that particles, in the magnetic dissipation process, are repeatedly accelerated.Comment: 9 pages including 7 figures and 1 table, MNRAS in pres