Observation of the TeV gamma-ray source MGRO J1908+06 with ARGO-YBJ

The extended gamma ray source MGRO J1908+06, discovered by the Milagro air shower detector in 2007, has been observed for about 4 years by the ARGO-YBJ experiment at TeV energies, with a statistical significance of 6.2 standard deviations. The peak of the signal is found at a position consistent with the pulsar PSR J1907+0602. Parametrizing the source shape with a two-dimensional Gauss function we estimate an extension \sigma = 0.49 \pm 0.22 degrees, consistent with a previous measurement by the Cherenkov Array H.E.S.S.. The observed energy spectrum is dN/dE = 6.1 \pm 1.4 \times 10^-13 (E/4 TeV)^{-2.54 \pm 0.36} photons cm^-2 s^-1 TeV^-1, in the energy range 1-20 TeV. The measured gamma ray flux is consistent with the results of the Milagro detector, but is 2-3 times larger than the flux previously derived by H.E.S.S. at energies of a few TeV. The continuity of the Milagro and ARGO-YBJ observations and the stable excess rate observed by ARGO-YBJ along 4 years of data taking support the identification of MGRO J1908+06 as the steady powerful TeV pulsar wind nebula of PSR J1907+0602, with an integrated luminosity above 1 TeV about 1.8 times the Crab Nebula luminosity.Comment: 6 pages, accepted for pubblication by ApJ. Replaced to correct the author lis

Charge Delocalization in Self-Assembled Mixed-Valence Aromatic Cation Radicals

The spontaneous assembly of aromatic cation radicals (D+•) with their neutral counterpart (D) affords dimer cation radicals (D2+•). The intermolecular dimeric cation radicals are readily characterized by the appearance of an intervalence charge-resonance transition in the NIR region of their electronic spectra and by ESR spectroscopy. The X-ray crystal structure analysis and DFT calculations of a representative dimer cation radical (i.e., the octamethylbiphenylene dimer cation radical) have established that a hole (or single positive charge) is completely delocalized over both aromatic moieties. The energetics and the geometrical considerations for the formation of dimer cation radicals is deliberated with the aid of a series of cyclophane-like bichromophoric donors with drastically varied interplanar angles between the cofacially arranged aryl moieties. X-ray crystallography of a number of mixed-valence cation radicals derived from monochromophoric benzenoid donors established that they generally assemble in 1D stacks in the solid state. However, the use of polychromophoric intervalence cation radicals, where a single charge is effectively delocalized among all of the chromophores, can lead to higher-order assemblies with potential applications in long-range charge transport. As a proof of concept, we show that a single charge in the cation radical of a triptycene derivative is evenly distributed on all three benzenoid rings and this triptycene cation radical forms a 2D electronically coupled assembly, as established by X-ray crystallography

MSEC2007-31060 SOME INVESITIGATIONS INTO MULTI-OBJECTIVE OPTIMIZATION OF WIRE ELECTRO- DISCHARGE MACHINING OF AL/SIC P COMPOSITES

ABSTRACT Non-traditional process like wire electro-discharge machining (WEDM) is found to show a promise for machining metal matrix composites (MMCs). However, the machining information for the difficult-to-machine particle-reinforced material is inadequate. This paper is focused on experimental investigation to examine the effect of electrical as well as nonelectrical machining parameters on performance in wire electro-discharge machining of metal matrix composites (Al/SiC p ). Taguchi orthogonal arrays were employed to study the effects of combinations of voltage, current, pulse on-time, off-time, and wire speed and wire tension on kerf width and cutting speed. Voltage, current, and on-time were found to have significant effect on cutting speed and kerf width. The optimum machining parameter combinations were obtained for cutting speed and kerf width separately. Further, multi-objective optimization was done using Taguchi-Grey relational analysis. The process has been improved with the aid of Grey relational analysis and Taguchi orthogonal array. The results have been verified with confirmation experiments. INTRODUCTION In the drive for high performance materials for aerospace applications, metal matrix composites have been investigated by both industry and academia since the 1970s. These materials do not need any introduction today. Over the last three decades metal matrix composites (MMCs) have received attention all over the world because of their attractive properties, relative ease in fabrication technology and their potential to be availabl

FORMULATION AND EVALUATION OF PH-DEPENDENT SUSTAINED RELEASE TABLET OF BEMPEDOIC ACID

The main goal about this research had been to create a sustained release tablet formulation that is pH-dependent for Bempedoic Acid, a drug that is acid labile and poorly soluble in water in the stomach environment. The objective of formulation is to enable the dose form that the stomach will not dissolve, it begins break down in upper small intestine, as well as to release the active ingredient gradually and under controlled circumstances. As part of the preformulation investigations, the drug-excipient compatibility, and partition coefficient were examined. In order to create a sustained release tablet that is pH-dependent, Eudragit® L100 and Eudragit® S100 were combined. It was established how the drug release rate was affected by the solubilizer, binder, coated concentration of polymers, plasticizer, and pore former. The findings showed that while no drug was found when the drug was submitted to release of drugs experiments in hydrochloric acid at 0.1 mol/L for two hours, almost within 12 hours, 90% of the medication was released in the pH 6.8 phosphate buffer in a sustained release fashion. The coated film\u27s pore development and/or stress sites were engaged in the drug release mechanism. For three months, the coated tablets remained stable at 40°C with a relative humidity of 75%. These outcomes demonstrated a viability in the coated tablet system containing Bempedoic Acid, which could aid in the effective management of cardiovascular illness

Laboratory spectra of amorphous and crystalline olivine: An application to comet Halley IR spectrum

Among the various silicates proposed as components of cosmic dust grains, olivine is considered one of the most likely materials. In this work we present the infrared spectra of three different types of olivine grains: crystalline, amorphous, and synthetic (also amorphous). While the first and second sample derive from the same natural mineral, the third one has been prepared in laboratory according to the relative cosmic abundances of the elements. The experiment data are used to fit the emission feature observed in the comet Halley spectrum between 8 and 13 {mu}m. Satisfactory results are obtained by using synthetic olivine mixed with a small amount (5%) of crystalline grains. 4 refs., 2 figs

Exposure–response relationship of AMG 386 in combination with weekly paclitaxel in recurrent ovarian cancer and its implication for dose selection

To characterize exposure-response relationships of AMG 386 in a phase 2 study in advanced ovarian cancer for the facilitation of dose selection in future studies.A population pharmacokinetic model of AMG 386 (N = 141) was developed and applied in an exposure-response analysis using data from patients (N = 160) with recurrent ovarian cancer who received paclitaxel plus AMG 386 (3 or 10 mg/kg once weekly) or placebo. Reduction in the risk of progression or death with increasing exposure (steady-state area under the concentration-versus-time curve [AUC(ss)]) was assessed using Cox regression analyses. Confounding factors were tested in multivariate analysis. Alternative AMG 386 doses were explored with Monte Carlo simulations using population pharmacokinetic and parametric survival models.There was a trend toward increased PFS with increased AUC(ss) (hazard ratio [HR] for each one-unit increment in AUC(ss), 0.97; P = 0.097), suggesting that the maximum effect on prolonging PFS was not achieved at the highest dose tested (10 mg/kg). Among patients with AUC(ss) ≥ 9.6 mg h/mL, PFS was 8.1 months versus 5.7 months for AUC(ss) < 9.6 mg h/mL and 4.6 months for placebo. No relationship between AUC(ss) and grade ≥ 3 adverse events was observed. Simulations predicted that AMG 386 15 mg/kg once weekly would result in an AUC(ss) ≥ 9.6 mg h/mL in > 90% of patients with median PFS of 8.2 months versus 5.0 months for placebo (HR [15 mg/kg vs. placebo], 0.56).Increased exposure to AMG 386 was associated with improved clinical outcomes in recurrent ovarian cancer, supporting the evaluation of a higher dose in future studies

Deep learning-based phenotyping reclassifies combined hepatocellular-cholangiocarcinoma.

Primary liver cancer arises either from hepatocytic or biliary lineage cells, giving rise to hepatocellular carcinoma (HCC) or intrahepatic cholangiocarcinoma (ICCA). Combined hepatocellular- cholangiocarcinomas (cHCC-CCA) exhibit equivocal or mixed features of both, causing diagnostic uncertainty and difficulty in determining proper management. Here, we perform a comprehensive deep learning-based phenotyping of multiple cohorts of patients. We show that deep learning can reproduce the diagnosis of HCC vs. CCA with a high performance. We analyze a series of 405 cHCC-CCA patients and demonstrate that the model can reclassify the tumors as HCC or ICCA, and that the predictions are consistent with clinical outcomes, genetic alterations and in situ spatial gene expression profiling. This type of approach could improve treatment decisions and ultimately clinical outcome for patients with rare and biphenotypic cancers such as cHCC-CCA