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The Large Magellanic Cloud (LMC) is the Milky Way’s most massive satellite galaxy, which only recently (~2 billion years ago) fell into our Galaxy. As stellar atmospheres preserve the composition of their natal cloud, the LMC’s recent infall makes its most ancient, metal-deficient (‘low-metallicity’) stars unique windows into early star formation and nucleosynthesis in a formerly distant region of the high-redshift universe. Here we present the elemental abundances of ten stars in the LMC with iron-to-hydrogen ratios ranging from ~1/300th to ~1/12,000th that of the Sun. Our most metal-deficient star is markedly more metal-deficient than any in the LMC with available detailed chemical abundance patterns and was probably enriched by a single extragalactic ‘first-star’ supernova. This star lacks appreciable carbon enhancement, as does our overall sample, unlike the lowest-metallicity stars in the Milky Way. This and other abundance differences affirm that the extragalactic early LMC experienced diverging enrichment processes compared to the early Milky Way. Early element production, driven by the earliest stars, thus, appears to proceed in an environment-dependent manner. Ten stars in the Large Magellanic Cloud exhibit very low elemental abundances, suggesting that they have experienced enrichment by the earliest generations of stars only. These stars provide a window into a distant region of the high-redshift universe.

We investigate the abundance of 19F in the Sun through the nucleosynthesis scenario. In addition, we calculate the rate equations and reaction rates of the nucleosynthesis of 19F at different temperature scale. Other important functions of this nucleosynthesis (nuclear partition function and statistical equilibrium conditions) are also obtained. The resulting stability of 19F occurs at nucleus with A = 19 and Mass Excess = -1.4874 MeV. As a result, this will tend to a series of neutron captures and beta-decay until 19F is produced. The reaction rate of 15N (α, γ) 19F was dominated by the contribution of three low-energy resonances, which enhanced the final 19F abundance in the envelope.

Formaldehyde is a highly reactive impurity that can be found in many pharmaceutical excipients. Trace levels of this impurity may affect drug product stability, safety, efficacy, and performance. A static headspace gas chromatographic method was developed and validated to determine formaldehyde in pharmaceutical excipients after an effective derivatization procedure using acidified ethanol. Diethoxymethane, the derivative of formaldehyde, was then directly analyzed by GC-FID. Despite the simplicity of the developed method, however, it is characterized by its specificity, accuracy, and precision. The limits of detection and quantification of formaldehyde in the samples were of 2.44 and 8.12 µg/g, respectively. This method is characterized by using simple and economic GC-FID technique instead of MS detection, and it is successfully used to analyze formaldehyde in commonly used pharmaceutical excipients.

This study demonstrated the impact of formic acid (FAc), a common reactive impurity in pharmaceutical excipients, on the stability of mirabegron (MB). The investigation of MB‐excipient compatibility tests revealed the formation of a new degradation product, FAc‐DP, at 0.2% after 7 days of isothermal stress at 55°C. FAc‐DP was synthesized and characterized as N‐formyl MB using liquid chromatography–mass spectrometry (LC‐MS) and both 1D and 2D nuclear magnetic resonance spectroscopy (NMR).

We illustrate the evolution of the peculiar behavior of the high mass X-ray binary GX 301-2, through the wind accretion model. We found that the donor of this system has 43 M⨀ and clearly it experienced of a mass exchange. As a result, the low terminal velocity of the wind from donor (1200 km/s), slow rotation and the relatively low luminosity (3.1×1035erg/s), can easily fed the neutron star via the stellar wind with enough accretion matter. This will lead to explain the observed X-rays. It has been shown that the characteristics of mass-loss rate through stellar winds would reasonably be expected to alter the changes in wind velocity by X-rays.

Canagliflozin is a newly approved drug for type II diabetes mellitus, in the present work, a strategy based on high performance liquid chromatography combined with mass spectrometry (HPLC-UV/MS) method was proposed to systematically characterize the in vivo metabolites of canagliflozin in Rats. [...]of that and besides the parent drug, a total of 12 metabolites of canagliflozin were detected and identified.it was indicated that the metabolic pathways of canagliflozin in rats included: oxidation (as a main rout), glucuronation, and hydroxylation The result could provide valuable information regarding the metabolism of canagliflozin in rats, which contribute to better understanding of its action mechanism. For Rats feces extracts, the mobile phase, consisting of water with 0.1% formic acid (A) and methanol with formic acid 0.1%(B), was delivered using a gradient program as follows: [Time (min)/ Pump B Value (%)] [0.01/15, 15/50, 20/75, 25/100 and 40/100], with a flow rate of 0.5ml/min For rat's plasma and urine, the mobile phase consisted of 0.1% formic acid (A) and acetonitrile (B) with a flow rate of 0.5 mL/min. The observed masses, elemental compositions and characteristic fragment ions of the proposed metabolites were all listed in Table 1 3.2Mass spectral fragmentation of Canagliflozin: In this study both positive and negative ESI (Electrospray ionization) modes were used to obtain higher responses of canagliflozin and other relative compounds in the MS spectra, and authentic canagliflozin was characterized by signal of deprotonated molecule([M-H]-) at m/z 479 (Fig.5,6) which gave production at m/z 445 (C24H26O5NFS) from loss of NH3, which further undergoes sequential loss of H2O to form ions at m/z 409 (C24H22O3NFS), and 377.

We investigate the abundance of 19 F in the Sun through the nucleosynthesis scenario. In addition, we calculate the rate equations and reaction rates of the nucleosynthesis of 19 F at different temperature scale. Other important functions of this nucleosynthesis (nuclear partition function and statistical equilibrium conditions) are also obtained. The resulting stability of 19 F occurs at nucleus with A = 19 and Mass Excess = -1.4874 MeV. As a result, this will tend to a series of neutron captures and beta-decay until 19 F is produced. The reaction rate of 15 N ( α, γ ) 19 F was dominated by the contribution of three low-energy resonances, which enhanced the final 19 F abundance in the envelope.

RP-HPLC coupled with tandem mass spectrometry and NMR have been used to characterize the degradation products [13] and further analytical techniques were used in order to investigate the degradation kinetics of Rivaroxaban including HPLC, TLC-densitometry, LC/MS/MS and UPLC-QTOF-MS/MS [14,15]. Since Rivaroxaban is not yet official in any of the pharmacopoeia [16-18], and there are only few studies dealing with its stability profile, the aim of this research was to develop a stability indicating method for determination of Rivaroxaban plus an identification, isolation and characterization of its degradation products (DPs) in order to identify its major degradation pathways, by using techniques of LC-MS, TLCdensitometry, NMR spectroscopy and FT-IR spectral data. 2. [...]DP2 and DP3 are hydrolysis degradation products which suggest that adding acid to the hydrolysis medium only help to accelerate the degradation and increase the formation of DP3, while the basic conditions also increase the speed of degradation, increase the formation of DP2 and lead to formation of DP1, which only appeared in basic hydrolysis. Both chromatographic methods were able to separate all the degradation products not only from Rivaroxaban but also from each other in stressed samples. [...]the methods proved to be selective and stability-indicating. [...]DP3 could be formed by hydrolysis of oxazolidine ring, where its molecular formula is Ci8H18QN3O3S and molecular weight is 391.

We present a detailed chemical abundance and kinematic analysis of six extremely metal-poor (\\(-4.2 \\leq\\) [Fe/H] \\(\\leq-\\)2.9) halo stars with very low neutron-capture abundances ([Sr/H] and [Ba/H]) based on high-resolution Magellan/MIKE spectra. Three of our stars have [Sr/Ba] and [Sr/H] ratios that resemble those of metal-poor stars in ultra-faint dwarf galaxies (UFDs). Since early UFDs may be the building blocks of the Milky Way, extremely metal-poor halo stars with low, UFD-like Sr and Ba abundances may thus be ancient stars from the earliest small galactic systems that were accreted by the proto-Milky Way. We label these objects as Small Accreted Stellar System (SASS) stars, and we find an additional 61 similar ones in the literature. A kinematic analysis of our sample and literature stars reveals them to be fast-moving halo objects, all with retrograde motion, indicating an accretion origin. Because SASS stars are much brighter than typical UFD stars, identifying them offers promising ways towards detailed studies of early star formation environments. From the chemical abundances of SASS stars, it appears that the earliest accreted systems were likely enriched by a few supernovae whose light element yields varied from system to system. Neutron-capture elements were sparsely produced and/or diluted, with \\(r\\)-process nucleosynthesis playing a role. These insights offer a glimpse into the early formation of the Galaxy. Using neutron-capture elements as a distinguishing criterion for early formation, we have access to a unique metal-poor population that consists of the oldest stars in the universe.

We report on the discovery of the first ultra metal-poor (UMP) star 2MASS~J20500194\\(-\\)6613298 (J2050\\(-\\)6613; \\mbox{[Fe/H] = \\(-4.05\\)}) selected from the Gaia BP/RP spectral catalog that belongs to the ancient Atari disk component. We obtained a high-resolution spectrum for the star with the MIKE spectrograph on the Magellan-Clay telescope. J2050\\(-\\)6613 displays a typical chemical abundance pattern for UMP stars, including carbon and zinc enhancements. In contrast, J2050\\(-\\)6613 shows extremely high [Sr/Fe] and [Sr/Ba] ratios compared to other stars in the [Fe/H] \\(<-4.0\\) regime. J2050\\(-\\)6613 is most likely an early Population\\,II star that formed from a gas cloud that was chemically enriched by a massive Population\\,III hypernova (E \\(> 10^{52}\\)\\,erg). Such a Population\\,III core-collapse hypernova could simultaneously explain the origin of the abundance pattern of light and heavy elements of 2MASS~J2050\\(-\\)6613 if a large amount of Sr of \\(\\sim10^{-5}\\)\\,M\\(_{\\odot}\\) was produced, possibly by neutrino-driven \\textbf{(wind)} ejecta. Therefore, the abundance pattern of 2MASS~J2050\\(-\\)6613 places important constraints on Sr-producing nucleosynthesis sources operating in the Atari progenitor at the earliest times.