Copper (II) complexes containing mixed ligands were synthesized in dimethyl formamide (DMF). The intense cyan emission at an ambient temperature is observed for solid copper (II) complexes with ...salicylic acid and a 12% quantum yield with a fluorescent lifetime of approximately 10 ms. Hence, copper (II) complexes with salicylic acid are excellent candidates for photoactive materials. Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) reveal that the divalent copper metal centers coordinate with the nitrogen and oxygen lone pairs of conjugate ligands. XPS binding energy trends for core electrons in lower-lying orbitals are similar for all three copper (II) complexes: nitrogen 1s and oxygen 1s binding energies increase relative to those for undiluted ligands, and copper 2p3/2 binding energies decrease relative to that for CuCl2. The thermal behavior of these copper complexes reveals that the thermal stability is characterized by the following pattern: Cu(1,10-phenanthroline)(salicylic acid) > Cu(1,10-phenanthroline)(2,2’-bipyridine) > Cu(1,10-phenanthroline)(1-benzylimidazole)2.
Abstract
We report on the serendipitous discovery of a new transient in NGC 5907, at a peak luminosity of 6.4 × 1039 erg s−1. The source was undetected in previous 2012 Chandra observations with a ...3σ upper limit on the luminosity of 1.5 × 1038 erg s−1, implying a flux increase of a factor of >35. We analysed three recent 60 ks/50 ks Chandra and 50 ks XMM–Newton observations, as well as all the available Swift/XRT observations performed between 2017 August and 2018 March. Until the first half of 2017 October, Swift/XRT observations did not show any emission from the source. The transient entered the ultraluminous X-ray source (ULX) regime in less than two weeks and its outburst was still on-going at the end of 2018 February. The 0.3–10 keV spectrum is consistent with a single multicolour blackbody disc (kT ∼ 1.5 keV). The source might be an ∼30 M⊙ black hole accreting at the Eddington limit. However, although we did not find evidence of pulsations, we cannot rule out the possibility that this ULX hosts an accreting NS.
ABSTRACT
The REX (Radio-Emitting X-ray sources) is a catalogue produced by cross-matching X-ray data from the ROSAT-PSPC archive of pointed observations and radio data from the NRAO VLA Sky Survey, ...aimed at the selection of blazars. From the REX catalogue, we select a well-defined and statistically complete sample of high-energy peaked BL Lac (HBL). HBL are expected to be the most numerous class of extragalactic TeV-emitting sources. Specifically, we have considered only the REX sources in the currently planned CTA extragalactic survey area satisfying specific criteria and with an optical spectroscopic confirmation. We obtain 46 HBL candidates that we called Te-REX (TeV-emitting REX). We estimate the very high-energy gamma-ray emission, in the TeV domain, using an empirical approach i.e. using specific statistical relations between gamma-rays (at GeV energies) and radio/X-rays properties observed in bright HBL from the literature. We compare the spectral energy distributions (SEDs) with the sensitivities of current and upcoming Cherenkov telescopes and we predict that 14 Te-REX could be detectable with 50 h of observations of CTA and 7 of them also with current Cherenkov facilities in 50 h. By extrapolating these numbers on the total extragalactic sky, we predict that about 800 HBL could be visible in pointed CTA observations and ∼400 with current Cherenkov telescopes in 50 h. Interestingly, our predictions show that a non-negligible fraction (∼30 per cent) of the HBL that will be detectable by CTA is composed of relatively weak objects whose optical nuclear emission is swamped by the host-galaxy light and not (yet) detected by Fermi-LAT.
Background
We evaluated dietary intakes, body composition, micronutrient deficiency, and response to micronutrient supplementation in 47 patients before and for 6 months after laparoscopic sleeve ...gastrectomy (LSG).
Methods
Before, 3, and 6 months after LSG, we measured dietary intakes with food-frequency questionnaires, body composition with bioimpedance analysis (BIA) and bioelectrical vector analysis (BIVA), and plasma concentrations of iron, Zn, water-, and lipo-soluble vitamins.
Results
After LSG, energy intake significantly decreased and patients lost weight, fat mass, and free-fat mass. BIVA showed a substantial loss of soft tissue body cell mass (BCM) with no change in hydration.
Before surgery, 15 % of patients were iron deficient, 30 % had low levels of zinc and/or water-soluble vitamins, and 32 % of vitamin 25(OH)-D3. We treated iron deficiency with ferrous sulfate, isolated folate deficiency with N
5
-methyiltetrahydrofolate-Ca-pentahydrate, and deficiencies in vitamin B1, B12, or Zn, with or without concomitant folate deficiency, with multivitamin. No supplementation was given to vitamin 25(OH)-D3 deficient patients. At first follow-up, 7 % of patients developed new deficiencies in iron, 7 % in folic acid (
n
= 3), and 36 % in water-soluble vitamins and/or zinc whereas no new deficit in vitamin 25(OH)-D3 occurred. At final follow-up, deficiencies were corrected in all patients treated with either iron or folate but only in 32 % of those receiving multivitamin. Vitamin 25(OH)-D3 deficiency was corrected in 73 % of patients even though these patients were not supplemented.
Conclusion
LSG-induced weight loss is accompanied by a decrease in BCM with no body fluid alterations. Deficiencies in water-soluble vitamins and Zn respond poorly to multivitamin supplementation.
Temporal variability in flux and spectral shape is ubiquitous in the X-ray sky and carries crucial information about the nature and emission physics of the sources. The EPIC instrument on board the
...XMM-Newton
observatory is the most powerful tool for studying variability even in faint sources. Each day, it collects a large amount of information about hundreds of new serendipitous sources, but the resulting huge (and growing) dataset is largely unexplored in the time domain. The project called Exploring the X-ray transient and variable sky (EXTraS) systematically extracted all temporal domain information in the
XMM-Newton
archive. This included a search and characterisation of variability, both periodic and aperiodic, in hundreds of thousands of sources spanning more than eight orders of magnitude in timescale and six orders of magnitude in flux, and a search for fast transients that were missed by standard image analysis. All results, products, and software tools have been released to the community in a public archive. A science gateway has also been implemented to allow users to run the EXTraS analysis remotely on recent XMM datasets. We give details on the new algorithms that were designed and implemented to perform all steps of EPIC data analysis, including data preparation, source and background modelling, generation of time series and power spectra, and search for and characterisation of different types of variabilities. We describe our results and products and give information about their basic statistical properties and advice on their usage. We also describe available online resources. The EXTraS database of results and its ancillary products is a rich resource for any kind of investigation in almost all fields of astrophysics. Algorithms and lessons learnt from our project are also a very useful reference for any current and future experiment in the time domain.
In this article, graphene oxide nanosheets grafted with low molecular weight poly(ethylene terephthalate) were in situ synthesized via carboxylation, acyl chlorination and grafting modification in ...order to improve the compatibility between GO and PET phases and enhance the thermal stability and crystallization properties of PET. Fourier Transform Infrared (FTIR), X-ray Photoelectron Spectroscopy (XPS), and Atomic Force Microscopy (AFM) characterization results demonstrated that LMPET chains have been successfully grafted onto the surface of GO. To further investigate the influence of modified GO on properties of PET, modified PET was prepared by incorporating the GL-
-LMPET nanofillers into the PET matrix using the melt-blending method. Due to the similar polarity and strong interaction between LMPET and PET molecules, GL-
-LMPET nanofillers were homogeneously dispersed in PET matrix. Thermal properties and crystallization properties of obtained nanocomposites were systematically characterized using Differential Scanning Calorimetry (DSC), X-ray Diffraction (XRD), and Thermo Gravimetric Analysis (TGA). Results show that GL-
-LMPET nanofillers could improve the thermal stability of PET, e.g., increase up to 16.6 °C in temperature at the maximum rate of weight loss. In addition, the GL-
-LMPET also acts as an efficient nucleating agent for PET, exhibiting (1) higher crystallization temperatures; (2) higher degrees of crystallinity; and (3) faster rates of crystallization.
Abstract
About one-third of the 3033 γ-ray sources in the Third Fermi-LAT Gamma-ray Source Catalogue (3FGL) are unidentified and do not have even a tentative association with a known object; hence, ...they are defined as unassociated. Among Galactic γ-ray sources, pulsars represent the largest class, with over 200 identifications to date. About one-third of them are millisecond pulsars (MSPs) in binary systems. Therefore, it is plausible that a sizeable fraction of the unassociated Galactic γ-ray sources belong to this class. We collected X-ray and optical observations of the fields of 12 unassociated Fermi sources that have been classified as likely MSPs according to statistical classification techniques. To find observational support for the proposed classification, we looked for periodic modulations of the X-ray and optical flux of these sources, which could be associated with the orbital period of an MSP in a tight binary system. Four of the observed sources were identified as binary MSPs, or proposed as high-confidence candidates, while this work was in progress. For these sources, we present the results of our follow-up investigations, whereas for the others we present possible evidence of new MSP identifications. In particular, we discuss the case of 3FGL J0744.1−2523 that we proposed as a possible binary MSP based upon the preliminary detection of a 0.115 d periodicity in the flux of its candidate optical counterpart. We also found very marginal evidence of periodicity in the candidate optical counterpart to 3FGL J0802.3−5610, at a period of 0.4159 d, which needs to be confirmed by further observations.
Purpose
Papillary thyroid cancer (PTC) has good prognosis with a very low chance of mortality. The prognostic role of metastatic lymph node location was judged controversial and more recently (TNM ...VIII ed.) was considered to have no impact on the prognosis of older patients. The aim of the study was to evaluate the role of metastasized node location on PTC-related mortality.
Methods
PTC-related mortality was analysed in a consecutive retrospective series of 1653 PTC patients followed at our Thyroid Clinic (mean follow-up 5.9 years).
Results
Sixteen out of 1653 patients (0.96%) died because of PTC. Average age was 68 years at presentation and 74.7 at death. F/M ratio was 1:1. The death rate increased in relation to the lymph node status: 0.2% in N0, 0.3% in N1a and 3.0% in N1b.
Conclusions
The presence of lymph node metastases in the N1b compartment should be considered as a risk factor for distant metastatic spread and for cancer-related death and included in post-surgery evaluation.
Achieving multi-color luminescence with a single atomic center in transition metal complexes is a challenge. In this work, luminescent materials with tunable emission properties were realized by ...complexation between aluminum (III) ions with the ligands 3-hydroxyflavone (3-HF) and 5,7-dichloro-8-hydroxyquinoline (DCHQ). Aluminum (III) complexes with a single ligand emitted blue from 3-HF and green from DCHQ. High quantum yields (QYs) of 29.42% and 37.00% were also obtained, respectively. DFT calculations revealed details of the photophysical properties of the complexes. Correspondingly, cyan light emission was obtained if these two complexes were mixed together, from which the emission wavelength was located at 470 nm and the QY was 20.52%, under 290 nm excitation. More importantly, the cyan light emitted by the mixtures had selective sensitivity to different metal ions, resulting in either quenching the fluorescence (in the case of Fe3+) or enhancing the fluorescence (in the case of In3+). The fluorescence enhancement effect of In3+ on metal complexes has not been previously reported, neither for transition metal nor lanthanide ions. The linear quenching behavior of Fe3+ functions in the 50–700 μM concentration range, and the linear enhancement behavior of In3+ is demonstrated in the 300–800 mM concentration range.
A new way was meticulously designed to utilize the localized surface plasmon resonance (LSPR) effect and the light scattering effect of silver nanoplate (Ag-nPl) and core–shell Ag@SiO2 nanoparticles ...(Ag@SiO2-NPs) to enhance the photovoltaic performances of polymer solar cells (PSCs). To prevent direct contact between silver nanoparticles (Ag-NPs) and photoactive materials which will cause electrons quenching, bare Ag-nPl were spin-coated on indium tin oxide and silica capsulated Ag-NPs were incorporated to a PBDTTT-C-T:PC71BM active layer. As a result, the devices incorporated with Ag-nPl and Ag@SiO2-NPs showed great enhancements. With the dual effects of Ag-nPl and Ag@SiO2-NPs in devices, all wavelength sensitization in the visible range was realized; therefore, the power conversion efficiency (PCE) of PSCs showed a great enhancement of 14.0% to 8.46%, with an increased short-circuit current density of 17.23 mA·cm–2. The improved photovoltaic performances of the devices were ascribed to the LSPR effect and the light scattering effect of metallic nanoparticles. Apart from optical effects, the charge collection efficiency of PSCs was improved after the incorporation of Ag-nPl.
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