Search

Herein, we report room temperature Cr-doping for all-inorganic perovskites that have attracted great attention in recent years due to their extraordinary optical properties, low cost, and ease of synthesis. Incorporation of Cr 3 + ions into the perovskite crystal lattices is achieved by following a facile route involving an antisolvent recrystallization method at room temperature. It is shown that both Cr-doping and formation of crystals in the CsPbBr x Cl 3 − x phase are provided by increasing the concentration of the CrCl 3 solution. It is also observed that the doping procedure leads to the emergence of three types of distinctive peaks in the PL spectrum originating from CsPbBr x Cl 3 − x domains (476–427 nm), Cr-strained host lattices (515 nm), and midgap states formed by Cr dopants (675–775 nm). It is also found that the Cr-doped perovskites emitting a dark violaceous color change their color to white with a high color rendering index (88) in 30-day time intervals. Easy-tunable optical properties of all-inorganic Cs perovskites indicate their great potential for future optoelectronic device applications. [ABSTRACT FROM AUTHOR]

We present a detailed near-infrared chemical abundance analysis of 10 red giant members of the Galactic open cluster NGC 752. High-resolution (R  ≃ 45000) near-infrared spectral data were gathered with the Immersion Grating Infrared Spectrograph, providing simultaneous coverage of the complete H and K bands. We derived the abundances of H-burning (C, N, O), α (Mg, Si, S, Ca), light odd-Z (Na, Al, P, K), Fe-group (Sc, Ti, Cr, Fe, Co, Ni), and neutron-capture (Ce, Nd, Yb) elements. We report the abundances of S, P, K, Ce, and Yb in NGC 752 for the first time. Our analysis yields solar-metallicity and solar abundance ratios for almost all of the elements heavier than the CNO group in NGC 752. O and N abundances were measured from a number of OH and CN features in the H band, and C abundances were determined mainly from CO molecular lines in the K band. High-excitation |$\rm{C\,\small {I}}$| lines present in both near-infrared and optical spectra were also included in the C abundance determinations. Carbon isotopic ratios were derived from the R-branch band heads of first overtone (2−0) and (3−1) 12CO and (2−0) 13CO lines near 23 440 Å and (3−1) 13CO lines at about 23 730 Å. The CNO abundances and 12C/13C ratios are all consistent with our giants having completed 'first dredge-up' envelope mixing of CN-cyle products. We independently assessed NGC 752 stellar membership from Gaia astrometry, leading to a new colour–magnitude diagram for this cluster. Applications of Victoria isochrones and MESA models to these data yield an updated NGC 752 cluster age (1.52 Gyr) and evolutionary stage indications for the programme stars. The photometric evidence and spectroscopic light element abundances all suggest that the most, perhaps all of the programme stars are members of the helium-burning red clump in this cluster. [ABSTRACT FROM AUTHOR]

We present near-infrared spectroscopic analysis of 12 red giant members of the Galactic open cluster NGC 6940. High-resolution (R ≃ 45 000) and high-signal-to-noise ratio (S/N > 100) near-infrared H - and K -band spectra were gathered with the Immersion Grating Infrared Spectrograph (IGRINS) on the 2.7-m Smith Telescope at McDonald Observatory. We obtained abundances of H-burning (C, N, O), α (Mg, Si, S, Ca), light odd-Z (Na, Al, P, K), Fe-group (Sc, Ti, Cr, Fe, Co, Ni), and neutron-capture (Ce, Nd, Yb) elements. We report the abundances of S, P, K, Ce, and Yb in NGC 6940 for the first time. Many OH and CN features in the H band were used to obtain O and N abundances. C abundances were measured from four different features: CO molecular lines in the K band, high excitation C  i lines present in both near-infrared and optical, CH and C2 bands in the optical region. We have also determined 12C/13C ratios from the R -branch band heads of first overtone (2−0) and (3−1) 12CO and (2−0) 13CO lines near 23 440 Å and (3−1) 13CO lines at about 23 730 Å. We have also investigated the HF feature at 23 358.3 Å, finding solar fluorine abundances without ruling out a slight enhancement. For some elements (such as the α group), IGRINS data yield more internally self-consistent abundances. We also revisited the CMD of NGC 6940 by determining the most probable cluster members using Gaia DR2. Finally, we applied Victoria isochrones and mesa models in order to refine our estimates of the evolutionary stages of our targets. [ABSTRACT FROM AUTHOR]

We present the high-resolution (R ≈ 60 000), high signal-to-noise ratio (S/N ≃ 120) spectroscopic analysis of 12 red giant members of the Galactic open cluster NGC 6940. We applied Yonsei–Yale isochrones to the colour–magnitude diagram, which suggested an age of 1.1 Gyr for the cluster with a turn-off mass of 2 M⊙. Atmospheric parameters (Teff, log g, [Fe/H], and ξt) were determined via equivalent widths of Fe i, Fe ii, Ti i, and Ti ii lines. Calculated mean metallicity of the cluster is 〈[Fe/H]〉 = 0.04 ± 0.02. We derived abundances of α (Mg, Si, Ca), Fe-group (Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn), and n-capture (Y, La, Nd, Eu) elements to be about solar. Light odd-Z elements Na and Al are slightly enhanced in MMU 108 and MMU 152 by ∼0.34 and ∼0.16 dex, respectively. Abundances of light elements Li, C, N, O, and 12C/13C ratios were derived from spectrum syntheses of the Li i resonance doublet at 6707 Å, [O i] line at 6300 Å, C2 Swan bandheads at 5164 and 5635 Å, and strong 12,13CN system lines in the 7995–8040 Å region. Most carbon isotopic ratios are similar to those found in other solar-metallicity giants, but MMU 152 has an unusual value of 12C/13C = 6. Evaluation of the LiCNO abundances and 12C/13C ratios along with the present theoretical models suggests that all the red giants in our sample are core-helium-burning clump stars. [ABSTRACT FROM AUTHOR]

We present detailed chemical compositions of 10 red giant star members of the Galactic (open) cluster NGC 752, derived from high-resolution (R ≈ 60 000), high signal-to-noise (S/N ≥ 140) spectra. We confirmed cluster memberships by measuring the stellar radial velocities, and by deriving model atmosphere parameters (Teff, log g, [Fe/H] and ξt) from equivalent widths of Fe i, Fe ii, Ti i, and Ti ii lines. The metallicity we obtained for NGC 752 ([Fe/H] = −0.02 ± 0.05) is in good agreement with previous studies. We derived abundances of α (Mg, Si, Ca), light odd-Z (Na, Al), Fe-group (Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn), n-capture (Y, La, Nd, Eu), and p-capture (Li, C, N, O) species for each star. Furthermore, we also derived abundances of the LiCNO p-capture element group and carbon isotopic ratios, using synthetic spectrum analyses of the Li i 6707 Å resonance doublet, the [O i] line at 6300 Å, the CH G-band features near 4311 and 4325 Å, the C2 bandheads at 5160 and 5631 Å, and 12,13CN red system lines in the 7995-8040 Å region. By applying recent isochrones to NGC 752 photometry, and comparing the colour-magnitude diagram information to our Li abundances and 12C/13C ratios, we suggest that the 10 observed red giants can be separated into three first-ascent, six red-clump and one red horizontal branch star. [ABSTRACT FROM AUTHOR]

Background: The aim of this study is to determine whether the saliva analysis is an alternative to routine biochemical and immunoassay analyses in patients undergoing peritoneal dialysis (PD) or hemodialysis (HD). Methods: Study group consisted of 40 healthy control, 44 PD and 44 HD patients. Routine biochemical analytes, thyroid stimulating hormone (TSH), free T3, free T4, vitamin B12, ferritin and folic acid were measured. Results: Compared to pre-HD, urea, creatinine, uric acid, potassium levels were lower in post-HD, and calcium, magnesium, vitamin B12 levels were higher in post-HD both in saliva and serum. Positive correlations between saliva and serum were found for TSH and ferritin in control; urea, LDH, K in PD; urea, creatinine, alkaline phosphatase in pre-HD, and gamma-glutamyl transferase, iron, TSH in post-HD. There was a negative correlation only for creatine kinase and Mg in pre-HD and calcium in post-HD. In all groups, a positive correlation was found for urea, creatinine and a negative correlation was found for magnesium. Conclusions: Our study showed higher salivary urea and creatinine levels in patient groups, consistent with serum levels. Based on these results, salivary urea and creatinine levels may be useful in the evaluation of azotemia in dialysis patients

Salvia hypargeia Fisch. et Mey. (Lamiaceae) root extract, among 16 Salvia extracts, showed the highest activity against the human ovarian cancer cell line. Bioactivity-guided fractionation of this plant extract has yielded four abietane-type diterpenes [5,6-didehydro-7-hydroxytaxodone (1), 14-deoxycoleon U (= 6-hydroxysalvinolone) (2), demethylcryptojaponol (3), and salvicanaric acid (4)] two triterpenes (lupeol and lupeol-3-acetate), and a fatty acid mixture consisting mainly of palmitic acid (51.6%) and palmitoleic acid (6.4%). Compounds 2 and 3 were found to be active against A2780 human ovarian cancer cell line with IC50 values of 3.9 and 1.2 μ g/mL, respectively, and the fatty acid composition was the most active part of the extract (IC50 = 0.6 μ g/mL). [ABSTRACT FROM AUTHOR]

Multiple sclerosis (MS) is an autoimmune disease of the human central nervous system. It is one of the most common neurological disorders around the world and there is still no complete cure for MS. Purification of a terpenoid from Capparis ovata was carried out and its structure was elucidated as stigmast-5,22-dien-3β-ol, myristate (3β,22E-stigmasteryl myristate; SDM) by NMR and mass spectral analyses. No information regarding its any health effect is available in the literature. In the present study, we have described its effects on inflammatory factors such as the expression levels of cytokines, chemokines and adhesion molecules as well as apoptosis/infiltration and myelination in SH-SY5Y cells. The expression levels of proinflammatory or inflammatory cytokines and chemokines such as NF-κB1, CCL5, CXCL9, CXCL10 and HIF1A along with T-cell activating cytokines such as IL-6 and TGFB1 were significantly downregulated with SDM treatment. Moreover, the expression levels of the main myelin proteins such as MBP, MAG and PLP that are essential for healthy myelin architecture were significantly up-regulated. The results presented in this study strongly suggest that the SDM offers a unique possibility to be used with autoimmune diseases, including MS due to its activity on the manipulation of cytokines and the promotion of myelin formation.

This is the first study on phytochemical analysis and biological evaluation of Hypericum capitatum Choisy var. capitatum (HCC) endemic to Turkey with exception of essential oil analysis. Hyperoside and isoquercetin (25.7 ± 0.02 and 17.8 ± 0.02 μg/mg extract, respectively) were determined as the main compounds of the methanol extract. The major compounds of essential oil of HCC were found to be spathulenol and iso-longifolene (12.9% and 11.2%, respectively), and linoleic and palmitic acids (26.8% and 18.3%, respectively) were the main fatty acids. The methanol extract whose antioxidant activities studied for the first time was found to have moderate activity in β-carotene bleaching method (IC 50 :41.69 ± 1.29 μg/mL) and was found to be the most active extract in scavenging of DPPH free radical (IC 50 :16.82 ± 0.58 μg/mL) and ABTS cation radical (IC 50 :9.24 ± 0.28 μg/mL) and CUPRAC assays. Among the prepared four extracts of HCC, the methanol extract showed highest activity against Escherichia coli with an MIC value of 10 μg/mL, and the methanol extract was also found to have high DNA damage protective activity. The methanol extract exhibited high butyrylcholinesterase inhibitory activity (70.74%). Thus, H. capitatum var. capitatum can be regarded as a potential natural antioxidant, antimicrobial, anticholinesterase source and DNA damage inhibitor. [ABSTRACT FROM AUTHOR]