36 research outputs found
Neuroprotective effects of Ellagic acid on Neonatal Hypoxic Brain Injury via Inhibition of Inflammatory Mediators and Down-regulation of JNK/p38 MAPK Activation
Purpose: To investigate if ellagic acid exerts neuroprotective effects in hypoxic ischemic (HI) brain injury by inhibiting apoptosis and inflammatory responses.Methods: Separate groups of rat pups from post-natal day 4 (D4) were administered with ellagic acid (10, 20 or 40 mg/kg body weight) orally till post- natal day 10 (D10). On D10, the rats were subjected to HI brain injury. Following HI injury, infarct size, weight and volume of the brain were measured. Apoptosis was assessed by Fluoro-Jade C staining. Expression of caspases (caspase-3, 8 and 9), apoptotic pathway proteins (Bax, Bad, Bcl-2 and Bcl-xL), MAPKs, NF κB(p65) and p-IK-Bα were assessed by western blotting. mRNA levels of inflammatory mediators (TNF-α, IL-1α, IL-1β, iNOS, COX-2) were analyzed.Results: Ellagic acidmarkedly (p < 0.05) reduced infarct size, volume and tissue loss. Significant (p < 0.05) reduction in neuroapoptosis was observed on pre treatment with ellagic acid. Expression levels of caspases, apoptotic pathway proteins and MAPK proteins were down-regulated with marked (p < 0.05) suppression of inflammatory mediators, NF-κB(p65) and p-IK-Bα.Conclusion: Ellagic acid affords neuroprotection in HI brain injury by inhibiting apoptosis, inflammatory responses and modulating the proteins of apoptotic and MAPK pathways. Thus, ellagic acid may be a potent candidate for the treatment of HI injury.Keywords: Brain injury, Ellagic acid, Hypoxia, Inflammatory mediators, Mitogen activated protein kinases, Neuroprotectiv
Anisotropic g factors of the tetragonal Cu²⁺ monomer in Tl-2223 superconductor
The gyromagnetic factors of the Cu²⁺ monomer in Tl-2223 superconductor are quantitatively investigated from the perturbation formulas of these factors for a 3d⁹ ion in a tetragonally elongated octahedron. The local tetragonal distortion of the system is attributable to the axial elongation along c axis, corresponding to the five-fold coordinated Cu²⁺(2) site with almost 30% longer Cu–O bond length for the apical oxygen as compared to the four planar ones. The significant anisotropic behaviors of the EPR spectra perpendicular to and parallel with the ab (CuO₂) layers are analyzed on the basis of the local tetragonal elongation
Causal structures and causal boundaries
We give an up-to-date perspective with a general overview of the theory of
causal properties, the derived causal structures, their classification and
applications, and the definition and construction of causal boundaries and of
causal symmetries, mostly for Lorentzian manifolds but also in more abstract
settings.Comment: Final version. To appear in Classical and Quantum Gravit
Robust estimation of bacterial cell count from optical density
Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data
Studies on the axial shift and the spin Hamiltonian parameters for Cr
The axial shift and the spin Hamiltonian parameters (zero-field splitting D, g factors and hyperfine structure constants) for Cr+ in BeO are theoretically studied in this work. The calculations are carried out by using the perturbation formulas of these parameters for a 3d5 ion under trigonally distorted tetrahedra based on the cluster approach containing both the crystal-field and charge transfer contributions. It is found that the impurity Cr+ may not occupy exactly the host Be2+ site but experience a small outward shift 0.01 Å away from the ligand triangle along the C3 axis. The above impurity axial shift leads to much smaller trigonal distortion than the host Be2+ site in BeO. The theoretical spin Hamiltonian parameters based on the above impurity axial shift are in good agreement with the observed values
Syntheses and Biological Evaluation of Costunolide, Parthenolide, and Their Fluorinated Analogues
Inspired by the biosynthesis of sesquiterpene
lactones (SLs), herein we report the asymmetric total synthesis of
the germacrane ring (<b>24</b>). The synthetic strategy features
a selective aldol reaction between β,γ-unsaturated chiral
sulfonylamide <b>15a</b> and aldehyde <b>13</b>, as well
as the intramolecular α-alkylation of sulfone <b>21</b> to construct a 10-membered carbocylic ring. The key intermediate <b>24</b> can be used to prepare the natural products costunolide
and parthenolide (PTL), which are the key precursors for transformation
into other SLs. Furthermore, the described synthetic sequences are
amenable to the total synthesis of SL analogues, such as trifluoromethylated
analogues <b>32</b> and <b>45</b>. Analogues <b>32</b> and <b>45</b> maintained high activities against a series
of cancer cell lines compared to their parent PTL and costunolide,
respectively. In addition, <b>32</b> showed enhanced tolerance
to acidic media compared with PTL. To our surprise, PTL and <b>32</b> showed comparable half-lives in rat plasma and in the presence
of human liver microsomes