Impairment in S-phase entry of splenocytes of Parp-1 knockout mice

One immediate cellular response to DNA damage is the polyADP-ribosylation reaction by poly(ADP-ribose) polymerase-1 (Parp-1). The importance of Parp-1 has been established in many cellular processes, such as the maintenance of genomic stability, DNA repair and cell-death induction. Here, we established Parp-1^−/− mice of C57BL/6J congenic strain and characterized the role of Parp-1 in cell-cycle progression. In this study, we also improved a method to observe G0/G1 to S-phase transition of splenocytes and bone marrow cells prepared from mice. The cells were cultured and stimulated with mitogens (50 μM ionomycin/1 μM phorbol 12, 13-dibutyrate). We found that addition of a commercially available growth supportive reagent, BM Condimed ^RH1, greatly enhanced the transition of G0/G1 to the S-phase, which was determined by bromodeoxyuridine (BrdU) incorporation to DNA. Using this method, G0/G1 to the S-phase entry was measured using splenocytes derived from Parp-1^−/−, Parp-1^+/− and wild-type (Parp-1^+/+) mice. DNA synthesis in Parp-1^+/+ and Parp-1^+/− splenocytes started from day 1 after addition of mitogens, whereas that in Parp-1^−/− cells started from day 2. The peak of the S-phase was at day 2 in all genotypes and notably DNA synthesis in Parp-1^−/− cells was approximately halved compared to Parp-1^+/+ cells on day 2, 3 and 4. These results suggested that Parp-1 is involved in positive regulation of S-phase entry in quiescent mouse splenocytes.     

Manifestation of the nuclear anapole moment in the thallium M1 transitions

We calculate the nuclear spin-dependent parity-nonconserving E1 amplitudes for the optical transition 6p _{1/2, F} →6p _{3/2, F′} and hyperfine transition 6p _{1/2, F} →6p _{1/2, F′} in ²⁰⁵Tl. The experimental limit placed upon the former amplitude by Vetter et al. [PRL 74, 2658 (1995)] corresponds to the anapole moment constant κ_a=?0.26±0.27.     

Stability of centrosome numbers in poly(ADP-ribose) polymerase-1- and poly(ADP-ribose) glycohydrolase-deficient mouse ES cells

Poly(ADP-ribose) polymerase-1 (Parp-1) localizes mainly in the nucleus and functions in DNA repair, genome stability and cell death regulation. Meanwhile, it also localizes in centrosomes and is involved in the regulation of centrosome duplication. An abnormal increase in centrosome numbers is frequently observed in Parp-1-deficient (Parp-1^−/−) mouse embryonic fibroblasts (MEFs) (Kanai et al. (2003) Mol. Cell. Biol. 23, 2451–2462). However, there are no studies on whether the centrosome abnormality occurs also in other cell types under Parp-1 deficiency. In this study, we report that Parp-1^−/− mouse embryonic stem (ES) cell lines did not show an abnormally increased number of centrosomes compared to wild-type ES cells. Recently, poly(ADP-ribose) glycohydrolase (Parg) has also been shown to localize in centrosomes (Ohashi et al. (2003) Biochem. Biophys. Res. Commun. 307, 915–921). The number of centrosomes of Parg-deficient (Parg^−/−) ES cells was also analyzed in this study and was found to be stable under Parg deficiency. We also examined centrosome numbers in wild-type, Parp-1^−/− and Parg^−/− ES cell lines after treatment with methylmethanesulfonate (MMS) or γ-irradiation. Although a slight increase in the number of centrosomes is observed in each genotype twenty-four hours after treatment with MMS at 50 μM or with γ-irradiation at 1.4 Gy, there was no difference among the genotypes. These results suggest that loss of Parp-1 and Parg is insufficient to induce abnormality in centrosome numbers in ES cells and that ES cells possibly possess a strict mechanism for the maintenance of a normal number of centrosomes.     

Statistical Inference for Ergodic Algorithmic Model (EAM), Applied to Hydrophobic Hydration Processes

The thermodynamic properties of hydrophobic hydration processes can be represented in probability space by a Dual-Structure Partition Function {DS-PF} = {M-PF} · {T-PF}, which is the product of a Motive Partition Function {M-PF} multiplied by a Thermal Partition Function {T-PF}. By development of {DS-PF}, parabolic binding potential functions α) RlnK_dual = (−ΔG°_dual/T) ={f(1/T)*g(T)} and β) RTlnK_dual = (−ΔG°_dual) = {f(T)*g(lnT)} have been calculated. The resulting binding functions are “convoluted” functions dependent on the reciprocal interactions between the primary function f(1/T) or f(T) with the secondary function g(T) or g(lnT), respectively. The binding potential functions carry the essential thermodynamic information elements of each system. The analysis of the binding potential functions experimentally determined at different temperatures by means of the Thermal Equivalent Dilution (TED) principle has made possible the evaluation, for each compound, of the pseudo-stoichiometric coefficient ±ξ_w, from the curvature of the binding potential functions. The positive value indicates convex binding functions (Class A), whereas the negative value indicates concave binding function (Class B). All the information elements concern sets of compounds that are very different from one set to another, in molecular dimension, in chemical function, and in aggregation state. Notwithstanding the differences between, surprising equal unitary values of niche (cavity) formation in Class A <Δh_for>_A = −22.7 ± 0.7 kJ·mol⁻¹ ·ξ_w⁻¹ sets with standard deviation σ = ±3.1% and <Δs_for>_A = −445 ± 3J·K⁻¹·mol⁻¹·ξ_w⁻¹J·K⁻¹·mol⁻¹·ξ_w⁻¹ with standard deviation σ = ±0.7%. Other surprising similarities have been found, demonstrating that all the data analyzed belong to the same normal statistical population. The Ergodic Algorithmic Model (EAM) has been applied to the analysis of important classes of reactions, such as thermal and chemical denaturation, denaturation of proteins, iceberg formation or reduction, hydrophobic bonding, and null thermal free energy. The statistical analysis of errors has shown that EAM has a general validity, well beyond the limits of our experiments. Specifically, the properties of hydrophobic hydration processes as biphasic systems generating convoluted binding potential functions, with water as the implicit solvent, hold for all biochemical and biological solutions, on the ground that they also are necessarily diluted solutions, statistically validated.     

Transmission of polar substituent effects across the cubane ring system: 19F substituent chemical shifts (SCS) of 4‐substituted (X) cub‐1‐yl fluorides revisited

¹⁹F NMR shieldings of 4‐substituted (X) cub‐1‐yl fluorides ( 4 ) for a set of substituents (X?H, NO₂, CN, NC, CF₃, COOH, F, Cl, HO, NH₂, CH₃, Si(CH₃)₃, Li, O^? and NH) covering a wide range of electronic substituent effects were calculated using the DFT‐GIAO theoretical model. The level of theory, B3LYP/6‐311+G(2d,p), provided ¹⁹F substituent chemical shifts (SCS) in good agreement with experimental values where known. By means of NBO analysis, various molecular parameters were obtained from the optimized geometries. Linear regression analysis was employed to explore the relationship between the calculated ¹⁹F SCS and polar field, resonance and group electronegativity substituent constants (σ_F, σ_R and σ_x, respectively) and also the NBO derived molecular parameters (fluorine natural charges (Q_n), electron occupancies on fluorine of lone pairs (n_F) and occupation number of the C? F antibonding orbital (σ_CF*)). The key determining parameters appear to be n_F and σ_CF*(occup). Both factors are a function of the electrostatic field influence of the substituent (σ_F effect) but are counteractive in their influence on the shifts. No evidence for a significant resonance effect influence on the shifts could be identified. Copyright © 2009 John Wiley & Sons, Ltd.     

The High-Resolution ν5 Band of Jet-Cooled Si2F6

Vibration-rotation spectra of the parallel ν₅ band of hexafluorodisilane have been measured in a supersonic free jet with 0.001 cm⁻¹ resolution. Three isotopic species, ^28,28Si₂F₆, ^28,29Si₂F₆, and ^28,30Si₂F₆, have been studied. The effect of internal rotation is not observed, indicating that the splitting is smaller than our spectral resolution. A very weak parallel band observed with a slight red shift from the ν₅ fundamental band has been assigned tentatively to the (ν₄ + ν₅)-ν₄ hot band.     

Calculated polar substituent effects on the stability of 3‐substituted(X) bicyclo[1.1.1]pent‐1‐yl cations and 4‐substituted(X) bicyclo[2.2.1]hept‐1‐yl cations: a DFT study

The effects of substituents on the stability of 3‐substituted(X) bicyclo[1.1.1]pent‐1‐yl cations (3) and 4‐substituted(X) bicyclo[2.2.1]hept‐1‐yl cations (4), for a set of substituents (X = H, NO₂, CN, NC, CF₃, CHO, COOH , F, Cl, HO, NH₂, CH₃, SiH₃, Si(CH₃)₃, Li, O^?, and NH₃⁺) covering a wide range of electronic substituent effects were calculated using the DFT theoretical model at the B3LYP/6‐311 + G(2d,p) and B3LYP/6‐31 + G (d) levels of theory, respectively. Linear regression analysis was employed to explore the relationship between the calculated relative hydride affinities (ΔE, kcal/mol) of the appropriate isodesmic reactions for 3/4 and polar field/group electronegativity substituent constants (σ_F and σ_χ, respectively). The analysis reveals that the ΔE values for both systems are best described by a combination of both substituent constants. The result highlights the importance of the σ_χ dependency of charge delocalization in these systems. Copyright © 2012 John Wiley & Sons, Ltd.     

Hyperfine structure investigations in the4F9/2 atomic ground state of191Ir and193Ir

The5d ⁷6s^{2 4}F_9/2 atomic ground state of¹⁹¹Ir and¹⁹³Ir has been studied using the atomic-beam magnetic-resonance method. The results are:¹⁹³Ir:g _J(⁴F_9/2)=1.29694 (3)¹⁹¹Ir:Δv(⁴F_9/2; F=6?F=5)=659.26496 (12) MHzΔv( ⁴F_9/2; F=5?F=4)=189.44002 (09) MHzΔv( ⁴F_9/2; F=3?F=4)=84.05040 (80) MHzA=57.52148 (04) MHzB=471.20425 (57) MHzC=?0.020 (30) kHz¹⁹³Ir:Δv( ⁴F_9/2; F=6?F=5)=660.09043 (12) MHzΔv( ⁴F_9/2; F=5?F=4)=224.47848 (13) MHzΔv( ⁴F_9/2; F=?F=4)=33.53453 (89) MHzA=62.65556 (05) MHzB=426.23546 (64) MHzC=0.020 (30) kHz Using the magnetic dipole moments known by NMR-technique [1] we obtained for the electric quadrupole moments as calculated from the hyperfine interaction constantsA andB:Q(¹⁹¹Ir)=0.78 (20) barns,Q(¹⁹³Ir)=0.70 (18) barns (uncorrected for core polarization effects). A calculation of the hyperfine anomaly yields:₁₉₁ Δ ₁₉₃=?0.00023 (10). The ratio of theB factors which should be the same as for the quadrupole moments turned out to be:B(¹⁹¹Ir)/B(¹⁹³Ir)=Q(¹⁹¹Ir)/Q(¹⁹³Ir)=1.105502(3).     

Rotational absorption spectrum of methylene fluoride in the 20–100 cm region

The pure rotational spectrum of CH₂F₂ was recorded in the 20–100 cm⁻¹ spectral range and analyzed to obtain rotation and centrifugal distortion constants. Analysis of the data yielded rotation constants: A = 1.6392173 ± 0.0000015, B = 0.3537342 ± 0.00000033, C = 0.3085387 ± 0.00000027, τ_aaaa = −(7.64 ± 0.46) × 10⁻⁵, τ_bbbb = −(2.076 ± 0.016) × 10⁻⁶, τ_cccc = −(9.29 ± 0.12) × 10⁻⁷, T₁ = (4.89 ± 0.20) × 10⁻⁶, and T₂ = −(1.281 ± 0.016) × 10⁻⁶cm⁻¹.     

Luminescent properties of nanoparticles YPXV1−XO4:Dy phosphors

Phosphors of nanoparticles YP_XV_1−XO₄:Dy³⁺ (0?X?1) have been prepared by a citrate sol-gel method. X-ray diffraction, transmission electron microscope (TEM), scanning electron microscope (SEM) and photoluminescence excitation and emission spectra were utilized to characterize the phosphors. The results of XRD showed that a solid solution formed in YP_XV_1−XO₄:Dy³⁺ phosphor series from X=0 to X=1 with zircon structure. TEM and SEM studies revealed that the obtained YP_XV_1−XO₄:Dy³⁺ nanocrystals appeared to be spherical with some agglomeration and their sizes ranged from 30 to 80 nm. Upon short ultraviolet excitation, the optical properties of all the powder presented that the characteristic transitions of Dy³⁺ due to ⁴F_9/2-⁶H_15/2 (blue) and ⁴F_9/2-⁶H_13/2 (yellow) were detected. Besides this, in the system of YP_XV_1−XO₄:Dy³⁺, the yellow-to-blue intensity ratio (Y/B) depended on the value of P/V greatly, with the increasing of X value and the decreased Y/B value. The phosphor found to yield white light when the value of X in the range of X=0.775-0.85, the optimum concentration for Dy³⁺ is 1 mol% of Y in the host, and the emission intensity increased with the annealing temperature.     

Carbon-13 and Fluorine-19 NMR Spectroscopy of the Supramolecular Solid p-tert-Butylcalix[4]arene ·α,α,α-trifluorotoluene

The supramolecular 1 : 1 host–guest inclusion compound, p-tert-butylcalix[4]arene ·α,α,α-trifluorotoluene, 1, is characterized by ¹⁹F and ¹³C solid-state NMR spectroscopy. Whereas the ¹³C NMR spectra are easily interpreted in the context of earlier work on similar host–guest compounds, the ¹⁹F NMR spectra of solid 1 are, initially, more difficult to understand. The ¹⁹F{¹H} NMR spectrum obtained under cross-polarization and magic-angle spinning conditions shows a single isotropic resonance with a significant spinning sideband manifold. The static ¹⁹F{¹H} CP NMR spectrum consists of a powder pattern dominated by the contributions of the anisotropic chemical shift and the homonuclear dipolar interactions. The ¹⁹F MREV-8 experiment, which minimizes the ¹⁹F–¹⁹F dipolar contribution, helps to identify the chemical shift contribution as an axial lineshape. The full static ¹⁹F{¹H} CP NMR spectrum is analysed using subspectral analysis and subsequently simulated as a function of the ¹⁹F–¹⁹F internuclear distance (D_FF = 2.25 ± 0.01 Å) of the rapidly rotating CF₃ group without including contributions from additional libration motions and the anisotropy in the scalar tensor. The shielding span is found to be 56 ppm. The width of the centerband in the ¹⁹F{¹H} sample-spinning CP NMR spectrum is very sensitive to the angle between the rotor and the magnetic field. Compound 1 is thus an attractive standard for setting the magic angle for NMR probes containing a fluorine channel with a proton-decoupling facility.     

Confirmation of sable QTL that modifies the effects of the Ay allele on yellow coat color on mouse chromosome 1

F₁-A^y mice between RR (aabbCC) and C57BL/6J-A^y (A^yaBBCC) have a much darker yellow coat color than do C57BL/6J-A^y. Quantitative trait locus (QTL) analysis was carried out to identify genes responsible for the darker modification of the yellow coat color (this has been traditionally termed “sable”). A significant sable QTL was identified on chromosome 1 (Dmyaq4, LOD score 15.5 for lightness, and 13.4 for color difference), in a chromosomal position similar to that of Dmyaq2, a sable QTL previously identified in C3H/HeJ. Another significant sable QTL was identified on chromosome 4 (Dmyaq5, LOD score 5.6 for lightness, and 4.3 for color difference) near the tyrosinase-related protein 1 (Tyrp1) locus. The effect of Dmyaq5 was significant only in the presence of the RR allele at Dmyaq4, suggesting that the Dmyaq4 (as well as Dmyaq2) is a novel coat color gene that may act up-stream of Tyrp1 signaling to increase eumelanin production.     

Spectroscopic constants of the known electronic states of lead monofluoride

Based on measurements made by mass-resolved 1 + 1′ + 1″ resonance-enhanced multiphoton ionization spectroscopy, we have determined new molecular constants describing the rotational and fine structure levels of the B, D, E, and F states of the most abundant isotopic variant ²⁰⁸Pb¹⁹F, and we summarize the spectroscopic constants for all the know electronic states of the radical. Many spectroscopic constants for the isotopologues ²⁰⁶Pb¹⁹F and ²⁰⁷Pb¹⁹F have also been determined. The symmetry of the D-state is found to be ²Π_1/2, and the F-state is found to be an Ω = 3/2 state.     

Growth and scintillation properties of (Lu1 − x Tmx)2SiO5 [x = 0.001, 0.01, 0.1, 1]

(Lu_1 − xTm_x)₂SiO₅ (x = 0.001, 0.01, 0.1, 1) single crystalline scintillators were grown by the μ-PD method. In transmittance measurement, absorption bands due to Tm³⁺ 4f–4f transitions were observed at 260, 292, 356, 463, 680 and 790 nm and they could be ascribed to the transition from the ³H₆ ground state to its excited states, ¹I₆, ³P₆,¹D₂, ¹G₄, ³F₃ and ³H₄, respectively. Strong emission peak due to ¹D₂ → ³F₄ transition of Tm³⁺ was shown at 453 nm under X-ray irradiation. Photoluminescence decay time constant caused by this transition were evaluated to be 11.9 μs. Tm 1% doped one exhibited the highest light yield of 3530 ± 200 photons/MeV when excited by ¹³⁷Cs gamma-ray exposure.     

Calculated polar substituent effects on the stability of 4‐substituted(X) ‐ cub‐1‐yl and ‐bicyclo[2.2.2]oct‐1‐yl cations: a DFT study

The effects of substituents on the stability of 4‐substituted(X) cub‐1‐yl cations ( 2 ), as well as the benchmark 4‐substituted(X) bicyclo[2.2.2]oct‐1‐yl cation systems ( 7 ), for a set of substituents (X = H, NO₂, CN, NC, CF₃, COOH , F, Cl, HO, NH₂, CH₃, SiH₃, Si(CH₃)₃, Li, O^?, and NH) covering a wide range of electronic substituent effects were calculated using the DFT theoretical model at the B3LYP/6‐311 + G(2d,p) level of theory. Linear regression analysis was employed to explore the relationship between the calculated relative hydride affinities (ΔE, kcal/mol) of the appropriate isodesmic reactions for 2 / 7 and polar field/group electronegativity substituent constants (σ_F and σ_χ, respectively). The analysis reveals that the ΔE values of both systems are best described by a combination of both substituent constants. This highlights the distinction between through‐space and through‐bond electronic influences characterized by σ_F and σ_χ, respectively. Copyright © 2010 John Wiley & Sons, Ltd.     

Configurational Entropy Relaxation of Silica Glass—Molecular Dynamics Simulations

Vitreous silica was modelled using molecular dynamics (MD). The glass structure was transferred into an undirected graph and decomposed into disjoint structural units that were ideally mixed to calculate the configurational entropy. The Debye relaxation model was suggested to simulate the evolution of entropy during the cooling of the system. It was found that the relaxation of the configurational entropy of MD corresponds to the effective cooling rate of 6.3 × 10⁶ Ks⁻¹ and its extrapolation to 0.33 Ks⁻¹ mimics the glass transition with T_g; close to the experimental value. Debye relaxation correctly describes the observed MD evolution of configurational entropy and explains the existence of freezing-in temperature and the shape of the curve in the transition region.     

New observation of the , 1Δg, and 2Πg states and molecular constants with all Li2, Li2, and LiLi data

This paper reports our new observation of the , 1³Δ_g (v = 2–4), and 2³Π_g (v = 2–8) states of ⁶Li⁷Li by continuous wave perturbation facilitated optical–optical double resonance spectroscopy. Combining our new experimental term values of ⁶Li⁷Li with the available experimental data of ⁶Li₂ and ⁷Li₂, molecular constants and potential energy curves by Rydberg–Klein–Rees and direct-potential-fit techniques have been determined. Born-Oppenheimer breakdown parameters of the Li₂ 1³Δ_g and 2³Π_g states are calculated.     

Bonding in the Doubly Disordered Ba1−x Sn x Cl1+y F1−y Solid Solution

New materials were prepared in the SnF₂/BaCl₂ system by precipitation, and in the SnF₂/BaCl₂/BaF₂ system by direct reactions at high temperature in dry conditions. Stoichiometric BaSn₂Cl₂F₄ and BaSnClF₃?0.8H₂O, and a wide Ba_1?x Sn _x Cl_1+y F_1?y solid solution were prepared for the first time. Elemental analysis, X-ray diffraction and ¹¹⁹Sn Mössbauer spectroscopy were used for the characterization and study of bonding in the new materials. Mössbauer spectroscopy was shown to be an excellent method for probing both the type of bonding at tin(II) (ionic or covalent) and the bond strength at the tin sublattice. Tin(II) is covalently bonded in the stoichiometric phases and ionic (Sn²⁺ stannous ion) in the precipitated Ba_1?x Sn _x Cl_1+y F_1?y solid solution. The case of Ba_1?x Sn _x Cl_1+y F_1?y prepared in dry conditions is more complex. At negative y values (Cl: F <1) and more particularly at high x (solid solution rich in tin), a mixture of Sn²⁺ and covalent Sn(II) is observed, with a normal sublattice strength for Sn(II). At positive y values (Cl:F >1) and more particularly at low x (poor in tin), all the tin(II) is in the ionic form. Furthermore, at high x and high y, the tin(II) sublattice strength decreases so drastically that the tin recoil free fraction at ambient temperature is nearly zero. The bonding type and tin sublattice strength can be explained in terms of preference of covalent bonding with F and when tin clustering occurs, whereas an excess Cl around Sn(II) forms ionic bonding and tin rattling due to ionic size mismatch.     

Ab initio calculations of electronic structures of SrMoO4 crystals containing F and F color centers

The electronic structures of SrMoO₄ crystals containing F and F⁺ color centers with the lattice structure optimized are studied within the framework of the fully relativistic self-consistent Dirac–Slater theory, using a numerically discrete variational (DV-Xα) method. From the calculation, it is concluded that F and F⁺ color centers have donor energy level in the forbidden band. The electronic transition energies from the donor level to the bottom of the conduction band are 1.855 eV and 2.161 eV, respectively, which correspond to the 670 nm and 575 nm absorption bands. It is predicted that the 670 nm and 575 nm absorption bands originate from the F and F⁺ centers in SrMoO₄ crystals.