Equine estrogens differentially inhibit DNA fragmentation induced by glutamate in neuronal cells by modulation of regulatory proteins involved in programmed cell death

Background  

Recent data indicate that excitotoxicity of high levels of neurotransmitter glutamate may be mediated via programmed cell death (apoptosis) and that it can be prevented in HT22 mouse hippocampal cells by various equine estrogens with Δ⁸,17β-estradiol (Δ⁸,17β-E₂) being the most potent. In order to delineate the mechanism(s), glutamate-induced cell death of HT22 cells was assessed by measuring (a) DNA fragmentation in the presence or absence of 11 equine estrogens (components of the drug CEE); (b) cell death and (c) levels of anti-apoptotic (Bcl-2) and proapoptotic (Bax) proteins in the presence or absence of two equine estrogens, Δ⁸,17β-E₂ and 17β-estradiol (17β-E₂) by LDH release assay and Western blot analysis respectively.     

Quantum Gravitational Corrections to the Real Klein-Gordon Field in the Presence of a Minimal Length

The (D+1)-dimensional (β,β′)-two-parameter Lorentz-covariant deformed algebra introduced by Quesne and Tkachuk (J. Phys., A Math. Gen. 39, 10909, 2006), leads to a nonzero minimal uncertainty in position (minimal length). The Klein-Gordon equation in a (3+1)-dimensional space-time described by Quesne-Tkachuk Lorentz-covariant deformed algebra is studied in the case where β′=2β up to first order over deformation parameter β. It is shown that the modified Klein-Gordon equation which contains fourth-order derivative of the wave function describes two massive particles with different masses. We have shown that physically acceptable mass states can only exist for b < \frac18m²c²\beta<\frac{1}{8m^{2}c^{2}} which leads to an isotropic minimal length in the interval 10⁻¹⁷ m<(ΔX ⁱ )₀<10⁻¹⁵ m. Finally, we have shown that the above estimation of minimal length is in good agreement with the results obtained in previous investigations.     

Quantitative Analysis of Intracellular Calcium and Mitochondrial Kinetic Fluorescence Changes in GSNO-induced Thymocyte Early Apoptosis

A fluorescence microscopy imaging technique was applied to observe the single-cell kinetic changes of intracellular Ca²⁺ concentration ([Ca²⁺]_i) and mitochondrial membrane potential (ΔΨ_m) during the early stage of S-nitrosoglutathione (GSNO)-induced thymocytes apoptosis. The kinetic features of [Ca²⁺]_i and ΔΨ_m were quantitatively analyzed and compared by fitting the fluorescence intensity data. The mathematical parameter, inflection point which indicated the time point when [Ca²⁺]_i or ΔΨ_m changed the most rapidly, was proposed to analyze the fitting curve. The results revealed that the inflection point of [Ca²⁺]_i always appeared prior to that of ΔΨ_m during apoptosis induced by a certain GSNO concentration. Both the [Ca²⁺]_i and ΔΨ_m changed in a GSNO concentration-dependent manner. Another parameter, half-max effect point was also employed and displayed the similar results. Such quantitative analyses of real-time observations at the single-cell level are useful for interpreting the sequence of the biological events operating in GSNO-induced thymocyte apoptosis.     

Fluence dependant formation of <Emphasis Type="Italic">β</Emphasis>-SiC by ion implantation and thermal annealing

The β-SiC nanocrystals were synthesized by the implantation of carbon ions (C⁻) into silicon followed by high-temperature annealing. The carbon fluences of 1×10¹⁷, 2×10¹⁷, 5×10¹⁷, and 8×10¹⁷ atoms/cm² were implanted at an ion energy of 65 keV. It was observed that the average size of β-SiC crystals decreased and the amount of β-SiC crystals increased with the increase in the implanted fluences when the samples were annealed at 1100 °C for 1 h. However, it was observed that the amount of β-SiC linearly increased with the implanted fluences up to 5×10¹⁷ atoms/cm². Above this fluence the amount of β-SiC appears to saturate. The Fourier Transform Infrared Spectroscopy (FTIR), Raman Spectroscopy, and X-ray diffraction (XRD) techniques were used to characterize the samples.     

Kinetics of formation of O2(1Σ) molecules in reactions involving excited O2(1Δ) oxygen molecules and I(2P1/2) iodine atoms

The results of our experimental study of the kinetics of formation of O₂(¹Σ) molecules in energy-exchange reactions O₂(¹Δ) + I(⁵ p,² P _1/2) and O₂(a,¹Δ) + O₂(a,¹Δ) are presented. The ratio of rate constants was obtained for these reactions (4800 ± 300). Setting the rate constant of the deactivation of O₂(¹Σ) molecules on CO₂ molecules at 4.1 · 10^–13 cm³/s, we evaluated the rate constants for these reactions at a temperature of approximately 330 K: (1.7 ± 0.2) · 10⁻¹³ and (3.6 ± 0.5) · 10⁻¹⁷ cm³/s, respectively.     

A study of iso- and alio-valent cation doped Ag2SO4 solid electrolyte

2 SO₄. The solid solubility limits up to x≤3 mole% for monovalent, x≤5.27 mole% for divalent and x≤3.63 mole% for trivalent cation doped Ag₂SO₄ are set with XRD, SEM, IR and DSC techniques. A predominant dependence of conductivity on the ionic size of iso- and alio-valent cations is observed. In particular, the conductivity enhances in both α and β phases, despite having a lower ionic-size dopant cation (relative to that of Ag⁺) in the transition element cation doped Ag₂SO₄. Ca²⁺, Ba²⁺, Y³⁺ and Dy³⁺ doped samples show depature from the regular behaviour in the β-phase. The conductivity behaviour is discussed considering ionic size, valence and electronic structure of the guest cations. Received: 3 February 1997/Accepted: 27 May 1997     

Thermally stimulated luminescence of Ca3(PO4)2 and Ca9Ln(PO4)7 (Ln = Pr,Eu, Tb,Dy, Ho,Er, Lu)

The series of whitlockite compounds Ca₃(PO₄)₂ and Ca₉Ln(PO₄)₇ (Ln = Pr, Eu, Tb, Dy, Ho, Er, Lu) was studied in radioluminescence (RL) and thermally stimulated luminescence (TSL) excited by X-rays. f-f emission lines of Ln³⁺ were observed in RL for Ca₉Ln(PO₄)₇ (Ln = Pr, Eu, Tb, Dy, Ho, Er) whereas d-d emission band of the impurity Mn²⁺ was observed in Mn:Ca₃(PO₄)₂ and Mn:Ca₉Lu(PO₄)₇ at 655 nm. In TSL, the Eu, Ho and Er compounds did not show any signal. As Eu³⁺, Ho³⁺ and Er³⁺ present the highest Ln³⁺/Ln⁴⁺ ionization potential (IP) of the series, this was interpreted as the inability of these lanthanides to trap a hole. On the contrary Pr³⁺ in Ca₉Pr(PO₄)₇, Tb³⁺ in Ca₉Tb(PO₄)₇, Dy³⁺ in Ca₉Dy(PO₄)₇, Mn²⁺ in Mn:Ca₃(PO₄)₂ and Mn:Ca₉Lu(PO₄)₇ were identified as hole traps and radiative recombination centers in the TSL mechanism. Ca₉Tb(PO₄)₇ was found to be a high intensity green persistent phosphor whereas Mn:Ca₉Lu(PO₄)₇ is a red persistent phosphor suitable for in vivo imaging application.     

Quark momentum-space charge distribution in deuteron and neutron/proton structure functions ratio

The electromagnetic polarizabilities of the nucleon are shown to be essentially composed of the nonresonant α _p(E ₀₊) = + 3.2, α _n(E ₀₊) = + 4.1, the t-channel α ^t _{p, n} = - β ^t _{p, n} = + 7.6 and the resonant β _{p, n}(P ₃₃(1232)) = + 8.3 contributions (in units of 10^-4fm^3). The remaining deviations from the experimental data Δα _p = 1.2±0.6, Δβ _p = 1.2±0.6, Δα _n = 0.8±1.7 and Δβ _n = 2.0±1.8 are contributed by a larger number of resonant and nonresonant processes with cancellations between the contributions. This result confirms that dominant contributions to the electric and magnetic polarizabilities may be represented in terms of two-photon coupling to the σ-meson having the predicted mass m _σ = 666MeV and two-photon width Γ _γγ = 2.6keV.     

Different methods for administering 17β-estradiol to ovariectomized rats result in opposite effects on ischemic brain damage

Background  

Numerous stroke studies have controversially shown estrogens to be either neuroprotective or neurodamaging. The discordant results observed in rat brain ischemia models may be a consequence of discrepancies in estrogen administration modes resulting in plasma concentration profiles far from those intended. To test this hypothesis we reproduced in detail and extended an earlier study from our lab using a different mode of 17β-estradiol administration; home-made silastic capsules instead of commercial slow-release 17β-estradiol pellets. Four groups of female rats (n = 12) were ovariectomized and administered 17β-estradiol or placebo via silastic capsules. All animals underwent MCAo fourteen days after ovariectomy and were sacrificed three days later.     

A Pyrene-based Highly Selective Turn-on Fluorescent Sensor for Copper(II) Ion and its Application in Live Cell Imaging

A new pyrene derivative (chemosensor 1) containing a picolinohydrazide moiety exhibits high selectivity for Cu²⁺ ion detection in mixed aqueous media (CH₃OH:H₂O = 7:3). Significant fluorescence enhancement was observed with chemosensor 1 in the presence of Cu²⁺. However, the metal ions Ag⁺, Ca²⁺, Cd²⁺, Co²⁺, Cu²⁺, Fe²⁺, Fe³⁺, Hg²⁺, K⁺, Mg²⁺, Mn²⁺, Ni²⁺, Pb²⁺, and Zn²⁺ produced only minor changes in fluorescence for the system. The apparent association constant (K _a) of Cu²⁺ binding in chemosensor 1 was found to be 2.75*10³ M⁻¹. The maximum fluorescence enhancement caused by Cu²⁺ binding in chemosensor 1 was observed over the pH range 5–8. Moreover, by means of fluorescence microscopy experiments, it is demonstrated that 1 can be used as a fluorescent probe for detecting Cu²⁺ in living cells.     

CW one-micron (4F3/2-4I11/2) laser oscillation of Nd3+ ions in the melilite-type crystal Ca2MgSi2O7:Nd3+(Na+) at its incommensurate–commensurate phase transition

The spectroscopic and stimulated-emission (⁴F_3/2→⁴I_11/2) properties of the novel melilite-type laser crystal Ca₂MgSi₂O₇:Nd³⁺(Na⁺) were studied in a temperature range that covers its incommensurate–commensurate (IC↔N) phase transition. The phase transition temperatures of both undoped Ca₂MgSi₂O₇ and the doped crystal were ascertained at 346.6 K (undoped) and 341.3 K (doped) by means of differential scanning calorimetry (DSC). The temperature-dependent spectroscopic and laser experiments showed a significant decrease in CW output power and a strong distortion of the generated lasing beam in the region of the phase transition. The observed crystal field disorder of Nd³⁺ lasants in Ca₂MgSi₂O₇:Nd³⁺(Na⁺) is dominantly due to occupation of the position of Ca²⁺ by cations of different valency, while the influence of incommensurability is of minor importance.     

Relation between spectroscopic constants with limited Dunham coefficients

Statement of Kaur and Mahajan [1] about the definition of Δ used by Chandra [2] is not correct. Even if we take Δ = μω _e ² r _e ² /2D_e, the relation between Δ and G(=8ω_ex_e/B_e) is obtained as Δ = 4.21452856G, provided the vibrational energy of a diatomic molecule is expressed in terms of limited Dunham coefficients, Y₁₀, Y₂₀, Y₀₁ and Y₁₁. This relation is still different from that of Kaur and Mahajan [3]     

Josephson and single-particle currents between partially dielectricized superconductors with charge-density waves

The amplitudes of the nonstationary Josephson current I ¹, the interference current I ², and the quasiparticle current J through symmetric and asymmetric tunnel junctions, including superconductors with charge density waves, are calculated. In the symmetric (s) case the dependence of the Josephson current I _s ¹ on the voltage V on the junction has a logarithmic singularity at |eV|=2Δ, Δ+D, and 2D, where , Δ and Σ are the superconducting and dielectric order parameters, and e is the unit charge. At temperatures T≠0 jumps appear in the current-voltage characteristics I _s ¹ (V) at |eV|=D−Δ. Jumps and singularities are observed in the currents I _s ² and J _s at the same voltages at which singularities and jumps appear in I _s ¹ , respectively. In the nonsymmetric (ns) junctions which include an ordinary superconductor, singularities and jumps occur at |eV|=D+Δ_BCS, Δ+Δ_BCS, and (for T≠0) |D−Δ_BCS| and |Δ−Δ_BCS|, where Δ_BCS is the order parameter of an ordinary superconductor. The quasiparticle current J _ns is an asymmetric function of the voltage V and does not depend on the sign of Σ. The results are compared with experiment. Fiz. Tverd. Tela (St. Petersburg) 39, 991–999 (June 1997)     

A New Highly Sensitive and Selective Fluorescent Cadmium Sensor

Condensation product (L) of salicylaldehyde and semicarbazide behaves as a fluorescent sensor for Cd²⁺ ion, in 1:1 DMSO:H₂O, over Mn²⁺, Fe²⁺, Ni²⁺, Co²⁺, Cu²⁺, Pb²⁺ and Hg²⁺ ions. The emission peak of L at λ_max = 520 nm, on excitation with 420 nm wavelength photons, showed an enhancement in intensity of ca 60-fold when interacted with Cd²⁺ ion. The intensity was however found to remain unaltered when interacted with metal ions—Mn²⁺, Fe²⁺, Ni²⁺, Co²⁺, Cu²⁺, Pb²⁺ and Hg²⁺. The intensity increases by approximately 20 fold on interaction with Zn²⁺ ion. The increase in the fluorescent peak can be explained on the basis of photo induced electron transfer (PET) mechanism. A 1:1 complexation between Cd²⁺ and L with log β = 4.25 has been proved.     

Effective nonlinear optical properties of shape distributed composite media

The effective linear and nonlinear optical properties of metal/dielectric composite media, in which ellipsoidal metal inclusions are distributed in shape, are investigated. The shape distribution function P(L _x, L _y) is assumed to be 2Δ^-2θ(L _x - 1/3 + Δ/3)θ(L _y - 1/3 + Δ/3)θ(2/3 + Δ/3 - L _x - L _y), where θ( ^{. . .} ) is the Heaviside function, Δ is the shape variance and L_i are the depolarization factors of the ellipsoidal inclusions along i-symmetric axes (i = x, y). Within the spectral representation, we adopt Maxwell-Garnett type approximation to study the effect of shape variance Δ on the effective nonlinear optical properties. Numerical results show that both the effective linear optical absorption α ∼ ωIm() and the modulus of the effective third-order optical nonlinearity enhancement |χ⁽³⁾ _e|/χ⁽³⁾ ₁ exhibit the nonmonotonic behavior with Δ. Moreover, with increasing Δ, the optical absorption and the nonlinearity enhancement bands become broad, accompanied with the decrease of their peaks. The adjustment of Δ from 0 to 1 allows us to examine the crossover behavior from no separation to large separation between optical absorption and nonlinearity enhancement peaks. As Δ → 0, i.e., the ellipsoidal shape deviates slightly from the spherical one, the dependence of |χ⁽³⁾ _e|/χ⁽³⁾ ₁ on Δ becomes strong first and then weak with increasing the imaginary part of inclusions' dielectric constant. In the dilute limit, the exact formula for the effective optical nonlinearity is derived, and the present approximation characterizes the exact results better than old mean field one does. Received 10 December 2002 Published online 4 June 2003 RID="a" ID="a"e-mail: lgaophys@pub.sz.jsinfo.net     

Dielectronic recombination rate coefficients for the Ni ${\sf I}$ isoelectronic sequence

Ab initio calculations of the total dielectronic recombination (DR) rate coefficients for thirteen ions along the NiI isoelectronic sequence in the ground state (Kr⁸⁺, Mo¹⁴⁺, Ag¹⁹⁺, Sn²²⁺, Xe²⁶⁺, Nd³²⁺, Gd³⁶⁺, Yb⁴²⁺, W⁴⁶⁺, Au⁵¹⁺, Pb⁵⁴⁺, At⁵⁷⁺, and U⁶⁴⁺) have been performed using the flexible atomic code. The level-by-level calculations are performed for evaluating the DR contributions through the relevant Cu-like autoionizing inner-shell excited 3l¹⁷4l^′n^′′l^′′ and 3l¹⁷5l^′n^′′l^′′ configuration complexes with n^′′ ≤15, which are associated with Δn=1 and Δn=2 core-excitations, respectively. The usual (n^′′)^-3 scaling law is found to be invalid for low-Z ions. A level-by-level extrapolation procedure is employed to obtain the contributions through higher n^′′ complexes. The decays to autoionizing levels followed possibly by radiative cascades could enlarge the rates at relatively high temperature by a factor up to about 23%. For the whole isoelectronic ions the contributions from 3s²3p⁶3d⁹ 4l^′n^′′l^′′ dominate the total DR rates while the contributions from the 3s²3p⁶3d⁹ 5l^′n^′′l^′′ configuration complexes are about 10-20% at relatively high temperature. On the basis of the calculated results, a general analytic formula for the total DR rate coefficients of all the ions with 36≤Z ≤92 along the NiI isoelectronic sequence is constructed. The comparisons of the rates obtained from the general formula with those from the detailed calculations show that the formula is of high precision, generally better than 3% accuracy for electron temperatures kT≥0.1E_I, where E_I is the ionization energy of the Cu-like ion. The present DR rates at temperature above 1.0E_I are larger than the previously published data by a factor above 30%. The commonly used semiempirical formula proposed by Burgess and modified by Merts may overestimate the rates at high temperature by a factor of about 2 for low-Z ions.     

A tunable green alkaline-earth silicon-oxynitride solid solution (Ca1? x Sr x )Si2O2N2:Eu2+ and its application in LED

A series of (Ca_1−x−y Sr _x )Si₂O₂N₂:yEu²⁺ (x=0.0–0.97, y=0.03) phosphors were synthesized by high-temperature solid-state reaction. The XRD patterns confirm the formation of a solid solution of (Ca_1−x−y Sr _x )Si₂O₂N₂:yEu²⁺. An intense tunable green light is observed with the increasing ratio of Sr/Ca. With an increase in x, the excitation and emission spectra show a redshift and blueshift, respectively, due to large centroid shift and small Stokes shift. The temperature dependent luminescence is also investigated in the temperature range of 77–450 K. The Huang–Rhys factor and the thermal-quenching temperature are determined. Intense green LEDs were successfully fabricated based on the (Ca_1−x−y Sr _x )Si₂O₂N₂:yEu²⁺ phosphor and near-ultraviolet (∼395 nm) GaN/blue (460 nm) InGaN chips. All the results indicate that the solid solution (Ca_1−x−y Sr _x )Si₂O₂N₂:yEu²⁺ is a promising phosphor applicable to near-UV and blue LEDs for solid-state lighting.     

Alternative splicing variations in mouse CAPS2: differential expression and functional properties of splicing variants

Background  

Ca²⁺-dependent activator protein 2 (CAPS2/CADPS2) is a secretory vesicle-associated protein involved in the release of neurotrophin. We recently reported that an aberrant, alternatively spliced CAPS2 mRNA that lacks exon 3 (CAPS2Δexon3) is detected in some patients with autism. Splicing variations in mouse CAPS2 and their expression and functions remain unclear.     

The effect of Ca2+ in Li0.24+xLa0.59−xCaxTiO3-LaPO4 system

Li_0.2375+xLa_0.5875−xCa_xTiO₃-LaPO₄ fast ionic conductor was synthesized by high temperature solid-state reaction. A.C. impedance measurements show that the compositions of system have better conductivities in low doping content of Ca²⁺, but the conductivity goes down from 1.039·10⁻⁴ Scm⁻¹ to 1.173·10⁻⁵ Scm⁻¹ with increasing the content of Ca²⁺. The activation energy is about 20 kJ·mol⁻¹ in the temperature range of 25–400 °C. X-ray powder diffraction shows that the doping Ca²⁺ would not affect the structure of compositions in the system. The main phase is β-Li_0.24+xLa_0.59−xCa_xTiO₃ perovskite solid solution, LaPO₄ as a second phase also can be found. With the increasing content of Ca²⁺ (x>0.05), another phase CaTiO₃ appears obviously. IR measurement also indicates that the structure of compositions in the system would not be affected by Ca²⁺ doping. The decomposition voltage of Li_0.24+xLa_0.59−xCa_xTiO₃-LaPO₄ keeps on 1.6 V.     

Luminescent Donor-Acceptor β-Diketones: Modulation of Emission by Solvent Polarity and Group II Metal Binding

A class of aryl trifluoromethyl-containing β-diketones were synthesized via one step Claisen condensation. These π-conjugated diketones exhibit strong solvatochromism from intramolecular donor-acceptor charge transfer (CT). In addition, fluorescence quantum yields (ϕ_f) and lifetimes (τ_f) were measured in different solvents. Diketones exhibit bathochromic shifts in emission spectra with increasing solvent polarity. Fluorescence changes upon Group II metal binding were also studied. Despite the relatively simple structure, the anthracene-CF₃ diketone, atm, has strong binding affinity for Mg²⁺. A 70 nm blue shift and sixfold increase in intensity were observed upon addition of only one equivalent MgCl₂ in ethanol solution. It also shows selectivity for Mg²⁺ binding even in the presence of excess Ca²⁺. Association constant (K_a) calculations suggest atm has two orders of magnitude stronger chelation for divalent magnesium than for calcium. These findings make atm an attractive starting point for molecular probe and light emitting material design.