349 research outputs found

    2-(4-Iodo­phen­yl)-1,2,3,4-tetra­hydro­isoquinoline-1-carbonitrile

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    In the title compound, C16H13IN2, the benzene ring of the tetra­hydro­isoquinoline moiety makes a dihedral angle of 45.02 (9)° with the benzene ring of the 4-iodo­phenyl fragment. The N atom and the adjacent unsubstituted C atom of the tetra­hydro­isoquinoline unit are displaced by 0.294 (2) and 0.441 (3) Å, respectively, from the plane through the remaining eight C atoms. In the crystal, pairs of adjacent mol­ecules are linked into dimers by weak inter­molecular C—H⋯π inter­actions

    2-(4-Bromo­phen­yl)-3,4-dihydro­isoquinolin-2-ium thio­cyanate hemihydrate

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    In the title hemihydrated salt, C15H13BrN+·NCS−·0.5H2O, the two benzene rings are aligned at a dihedral angle of 46.9 (1)°. The six-membered heterocycle of the dihydro­isoquinoline unit adopts a half-chair conformation. The water mol­ecule and thio­cyanate ion are linked by O—H⋯N hydrogen bonds, generating a four-membered ring motif. In addition, C—H⋯O and C—H⋯S inter­actions link the components into a chain along the c axis. π–π inter­actions [centroid–centroid distance = 3.974 (2) Å] link the chains into sheets and further π—π [centroid–centroid distance = 3.746 (2) Å] and C—H⋯π inter­actions give rise to a three-dimensional nework

    Dense matter with eXTP

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    In this White Paper we present the potential of the Enhanced X-ray Timing and Polarimetry (eXTP) mission for determining the nature of dense matter; neutron star cores host an extreme density regime which cannot be replicated in a terrestrial laboratory. The tightest statistical constraints on the dense matter equation of state will come from pulse profile modelling of accretion-powered pulsars, burst oscillation sources, and rotation-powered pulsars. Additional constraints will derive from spin measurements, burst spectra, and properties of the accretion flows in the vicinity of the neutron star. Under development by an international Consortium led by the Institute of High Energy Physics of the Chinese Academy of Science, the eXTP mission is expected to be launched in the mid 2020s.Comment: Accepted for publication on Sci. China Phys. Mech. Astron. (2019

    2-(2-Hy­droxy­phen­yl)-3,4-dihydro­iso­quinolin-1(2H)-one

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    There are two independent mol­ecules in the asymmetric unit of the title compound, C15H13NO2, in both the six-membered dihydro­pyridine rings adopt a half-chair conformation. The two benzene rings make dihedral angles of 43.66 (10) and 62.22 (10)° in the two mol­ecules. In the crystal, the two independent mol­ecules are linked alternately by inter­molecular O—H⋯O hydrogen bonds, forming a zigzag chain along the c axis. Furthermore, inter­molecular C—H⋯π inter­actions link the chains into a three-dimensional network

    Enlarging the Stokes Shift by Weakening the π-Conjugation of Cyanines for High Signal-To-Noise Ratiometric Imaging

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    The signal-to-noise ratio (SNR) is one of the key features of a fluorescent probe and one that often defines its potential utility for in vivo labeling and analyte detection applications. Here, it is reported that introducing a pyridine group into traditional cyanine-7 dyes in an asymmetric manner provides a series of tunable NIR fluorescent dyes (Cy-Mu-7) characterized by enhanced Stokes shifts (≈230 nm) compared to the parent cyanine 7 dye (nm). The observed Stokes shift increase is ascribed to symmetry breaking of the Cy-Mu-7 core and a reduction in the extent of conjugation. The fluorescence signals of the Cy-Mu-7 dyes are enhanced upon confinement within the hydrophobic cavity of albumin or via spontaneous encapsulation within micelles in aqueous media. Utilizing the Cy-Mu-7, ultra-fast in vivo kidney labeling in mice is realized, and it is found that the liver injury will aggravate the burden of kidney by monitoring the fluorescence intensity ratio of kidney to liver. In addition, Cy-Mu-7 could be used as efficient chemiluminescence resonance energy transfer acceptor for the reaction between H O and bisoxalate. The potential utility of Cy-Mu-7 is illustrated via direct monitoring fluctuations in endogenous H O levels in a mouse model to mimic emergency room trauma

    A giant glitch from the magnetar SGR J1935+2154 before FRB 200428

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    Fast radio bursts (FRBs) are short pulses observed in radio frequencies usually originating from cosmological distances. The discovery of FRB 200428 and its X-ray counterpart from the Galactic magnetar SGR J1935+2154 suggests that at least some FRBs can be generated by magnetars. However, the majority of X-ray bursts from magnetars are not associated with radio emission. The fact that only in rare cases can an FRB be generated raises the question regarding the special triggering mechanism of FRBs. Here we report a giant glitch from SGR J1935+2154, which occurred approximately 3.1±2.53.1\pm2.5\,day before FRB 200428, with Δν=19.8±1.4\Delta\nu=19.8\pm1.4 {\rm μ\muHz} and Δν˙=6.3±1.1\Delta\dot{\nu}=6.3\pm1.1\,pHz s1^{-1}. The corresponding spin-down power change rate Δν˙/ν˙\Delta\dot\nu/\dot\nu is among the largest in all the detected pulsar glitches. The glitch contains a delayed spin-up process that is only detected in the Crab pulsar and the magnetar 1E 2259+586, a large persistent offset of the spin-down rate, and a recovery component which is about one order of magnitude smaller than the persistent one. The temporal coincidence between the glitch and FRB 200428 suggests a physical connection between the two. The internally triggered giant glitch of the magnetar likely altered the magnetosphere structure dramatically in favour of FRB generation, which subsequently triggered many X-ray bursts and eventually FRB 200428 through additional crustal cracking and Alfv\'en wave excitation and propagation

    Cost-Effectiveness of Hepatitis B Vaccination in Adults With Diagnosed Diabetes

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    OBJECTIVE To examine the cost-effectiveness of a hepatitis B vaccination program for unvaccinated adults with diagnosed diabetes in the U.S. RESEARCH DESIGN AND METHODS We used a cost-effectiveness simulation model to estimate the cost-effectiveness of vaccinating adults 20–59 years of age with diagnosed diabetes not previously vaccinated for or infected by hepatitis B virus (HBV). The model estimated acute and chronic HBV infections, complications, quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratios. Data sources included surveillance data, epidemiological studies, and vaccine prices. RESULTS With a 10% uptake rate, the intervention will vaccinate 528,047 people and prevent 4,271 acute and 256 chronic hepatitis B infections. Net health care costs will increase by 91.4million,and1,218QALYswillbegained,producingacosteffectivenessratioof91.4 million, and 1,218 QALYs will be gained, producing a cost-effectiveness ratio of 75,094 per QALY gained. Results are most sensitive to age, the discount rate, the hepatitis B incidence ratio for people with diabetes, and hepatitis B infection rates. Cost-effectiveness ratios rise with age at vaccination; an alternative intervention that vaccinates adults with diabetes 60 years of age or older had a cost-effectiveness ratio of $2.7 million per QALY. CONCLUSIONS Hepatitis B vaccination for adults with diabetes 20–59 years of age is modestly cost-effective. Vaccinating older adults with diabetes is not cost-effective. The study did not consider hepatitis outbreak investigation costs, and limited information exists on hepatitis progression among older adults with diabetes. Partly based on these results, the Advisory Committee on Immunization Practices recently recommended hepatitis B vaccination for people 20–59 years of age with diagnosed diabetes. </jats:sec

    Insight-HXMT on-orbit thermal control status and thermal deformation impact analysis

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    Purpose: The Hard X-ray Modulation Telescope is China's first X-ray astronomy satellite launched on June 15th, 2017, dubbed Insight-HXMT. Active and passive thermal control measures are employed to keep devices at suitable temperatures. In this paper, we analyzed the on-orbit thermal monitoring data of the first 5 years and investigated the effect of thermal deformation on the point spread function (PSF) of the telescopes. Methods: We examined the data of the on-orbit temperatures measured using 157 thermistors placed on the collimators, detectors and their support structures and compared the results with the thermal control requirements. The thermal deformation was evaluated by the relative orientation of the two star sensors installed on the main support structure. its effect was estimated with evolution of the PSF obtained with calibration scanning observations of the Crab nebula. Conclusion: The on-orbit temperatures met the thermal control requirements thus far, and the effect of thermal deformation on the PSF was negligible after the on-orbit pointing calibration.Comment: 25 pages, 35 figures, submitte
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