Determination of lead at physiological level in human biological materials using the total reflection X‐ray fluorescence analysis

Total reflection X‐ray fluorescence (TXRF) analysis was applied in determination of low concentration of lead in samples of human biological materials. The determination of lead in human serum and hair samples is presented as an example. In serum samples, lead concentration was in the range from 0.013 to 0.051 μg/g (median 0.024 μg/g). The reference ranges of lead content in hair are from 1.41 to 4.08 μg/g for men and from 1.18 to 3.29 μg/g for women groups, respectively. Because of Pb concentration range close to the detection limit of the TXRF method, the measurement needed evaluation of the best analytical conditions. This paper presents the results of this evaluation, namely internal standard selection, measurement conditions, and quantitative calibration of the spectrometer. Finally, as a result of evaluation, the detection limit was found on the level 0.001 μg/g (water solution) and about 0.005 μg/g for human hair samples and 0.007 μg/g for serum samples. The obtained values reach nearly the physiological lead level. The presented results are of practical importance for lead concentration studies in human biological materials using the TXRF method. Copyright © 2016 John Wiley & Sons, Ltd.     

Nonlinear quantum cosmology

We study the effects of an information-theoretically motivated nonlinear correction to the Wheeler-deWitt equation in the minisuperspace scheme for flat, k = 0, Friedmann–Robertson–Walker universes. When the only matter is a cosmological constant, the nonlinearity can provide a barrier that screens the original Big Bang, leading to the quantum creation of a universe through tunneling just as in the k = 1 case. When the matter is instead a free massless scalar field, the nonlinearity can again prevent a contracting classical universe from reaching zero size by creating a bounce. Our studies here are self-consistent to leading order in perturbation theory for the nonlinear effects.     

Cosmological Spacetimes Balanced by a Weyl Geometric Scale Covariant Scalar Field

A Weyl geometric approach to cosmology is explored, with a scalar field φ of (scale) weight −1 as crucial ingredient besides classical matter. Its relation to Jordan-Brans-Dicke theory is analyzed; overlap and differences are discussed. The energy-stress tensor of the basic state of the scalar field consists of a vacuum-like term Λg _{μ ν} with Λ depending on the Weylian scale connection and, indirectly, on matter density. For a particularly simple class of Weyl geometric models (called Einstein-Weyl universes) the energy-stress tensor of the φ-field can keep space-time geometries in equilibrium. A short glance at observational data, in particular supernovae Ia (Riess et al. in Astrophys. J. 659:98ff, 2007), shows encouraging empirical properties of these models.     

Transient crossing of phantom divide line w Λ = − 1 under Gauss–Bonnet interaction

Smooth double crossing of the phantom barrier w _Λ = − 1 has been found possible in cosmological model with Gauss–Bonnet-scalar interaction, in the presence of background cold dark matter. Such crossing has been observed to be a sufficiently late time phenomena and independent of the sign of Gauss–Bonnet-scalar interaction. The luminosity distance versus redshift curve shows a perfect fit with the Λ CDM model up to z = 3.5.     

An overview of <Emphasis Type="Italic">J</Emphasis>/<Emphasis Type="Italic">ψ</Emphasis> production in heavy ion collisions at PHENIX

This is an overview of the PHENIX J/ψ results in hot nuclear matter from heavy ion collisions. Current results for R _AA and v ₂ in Au+Au collisions, as well as R _AA from Cu+Cu collisions are included and discussed. A comparison is also done to cold nuclear matter effects using R _dAu results.     

Diffusion Tensor Magnetic Resonance Imaging in Ring-Enhancing Cerebral Lesions

The objective of this study is to determine differential diagnostic value of diffusion tensor imaging (DTI) in high-grade brain astrocytomas, brain solitary metastases and brain abscesses. 53 patients with cerebral solitary lesions which showed ring enhancement on contrast-enhanced T ₁-weighted images were enrolled in this study. Brain tissues were examined pathologically from 49 patients to confirm the cerebral occupational diseases. Four patients have been diagnosed with primary cancer plus brain solitary metastasis. DTI measurements were obtained from regions of interest placed on central cavity, white matter of the immediate peritumoral region (IPR) and cerebral white matter of the normal side. The cavity of high-grade astrocytoma and brain metastases displayed hypointense signals; most of the brain abscess cavities displayed high signal intensity except for one case with uneven signal intensity. Mean diffusivity (MD) and fractional anisotropy (FA) values could be used for differentiation between tumor and abscess in brain. The brain abscess cavities showed restricted diffusion and anisotropy [MD = (0.604 ± 0.13) × 10⁻³ mm²/s, FA = 0.185 ± 0.03], whereas the central portion of high-grade astrocytoma [MD = (2.76 ± 0.26) × 10⁻³ mm²/s, FA = 0.069 ± 0.02] and solitary brain metastases [MD = (2.82 ± 0.29) × 10⁻³ mm²/s, FA = 0.064 ± 0.02] showed unrestricted diffusion and isotropy. Brain abscess could be differentiated by MD and FA values in their cavities from brain tumors (P < 0.01). The IPRs were all depicted as hyperintense or isointense signals on diffusion-weighted imaging. The difference between FA values in the IPR of high-grade brain astrocytomas and other groups was statistically significant (P < 0.01). In conclusion, our results suggested the potential role of the cavity MD and FA values in the differential diagnoses of brain tumors and brain abscesses; meanwhile, high-grade astrocytomas could be distinguished from solitary metastases and abscesses by evaluating their corresponding FA values in the IPR on brain magnetic resonance imaging (MRI). Combined with conventional MRI, DTI may help radiologists to facilitate the differential diagnosis of ring-enhancing cerebral lesions in clinical practice.     

Direct and indirect detection of dark matter in D6 flavor symmetric model

We study fermionic dark matter in a non-supersymmetric extension of the standard model with a family symmetry based on D₆ ×[^(Z)]₂×Z₂D_{6} \times\hat{Z}_{2}\times Z_{2}. In our model, the final state of the dark matter annihilation is determined to be e ⁺ e ⁻ by the flavor symmetry, which is consistent with the PAMELA result. At first, we show that our dark matter mass should be within the range of 230 GeV–750 GeV in the WMAP analysis combined with μ→eγ constraint. Moreover, we simultaneously explain the experiments of direct and indirect detection, by simply adding a gauge and D ₆ singlet real scalar field. In the direct detection experiments, we show that the lighter dark matter mass ≃230 GeV and the lighter standard model Higgs boson ≃115 GeV are in favor of the observed bounds reported by CDMS II and XENON100. In the indirect detection experiments, we explain the positron excess reported by PAMELA through the Breit–Wigner enhancement mechanism. We also show that our model is consistent with there being no antiproton excess, as suggested by PAMELA.     

Sub-nanometer distances and cluster shapes in dense hydrogen and in higher levels of hydrogen Rydberg matter by phase-delay spectroscopy

The inter-atomic distances in potassium clusters of Rydberg matter (RM) at excitation levels n _B = 4–8 were recently measured by phase-delay spectroscopy (Holmlid, J Nanopart Res 12: 273, 2010). Excitation levels n _B < 4 with shorter inter-atomic distances exist for hydrogen clusters, and distances down to 140 pm are now measured with this light-scattering method. The clusters studied have maximum dimensions from 0.3 nm up to several tens of nm, often being planar. A weak carbon dioxide laser beam interacts with the clusters in a tunable RM cavity. A strong fringe structure is observed as a function of the end-grating angular position. Delay lengths in the clusters are derived from the fringe structure, corresponding to twice the distance between rows or planes in the clusters. Good agreement with predicted and a few previously measured distances in excitation levels n _B = 1, 2, and 3 is found. Close-packing is the main structure both in planar and 3D clusters. Planar clusters are only observed for n _B = 1 and 3, while 3D clusters are found in excitation levels n _B = 1, 2 and 3. The cluster–cluster distance in stacks of planar clusters for n _B = 2 and 3 is now observed for the first time.     

Biotoxicity of nanoparticles: effect of natural organic matter

Various natural organic matters (NOM) with different characteristics in aquatic environment may affect toxicity of leased nanoparticles, owing to interactions between NOM and nanoparticles. This study investigated the effect of NOM and physical characteristics of the effluent organic matter (EfOM) on the ecotoxicity of quantum dots (QD) using Daphnia magna. Organic matter samples were obtained from: Yeongsan River (YR-NOM), Dongbuk Lake (DL-NOM), Damyang wastewater treatment plant (EfOM), and Suwannee River NOM (SR-NOM). The QD was composed of a CdSe core, ZnS shell, and polyethylene glycol coating. The average size of the investigated QD was 4.8, 56.5, and 25.0 nm determined by transmission electron microscopy, dynamic light scattering, and asymmetric flow field-flow fractionation, respectively. The relative hydrophobicity of NOM was investigated using both specific UV absorbance at 254 nm and XAD-8/4 resins. The sorption of NOM on the QD was measured using a fluorescence quenching method. The highest hydrophobicity was exhibited by the SR-NOM, while the lowest was recorded for the DL-NOM. All tested NOMs significantly reduced the acute toxicity of D. magna when adsorbed to QD, and the order of effectiveness for each NOM was as follows: SR-NOM > EfOM > YS-NOM > DL-NOM. The sorption of NOM on the QD surface caused a decrease in the fluorescence intensity of QD at increasing NOM concentration. This suggests that the NOM coating influenced the physicochemical characteristics of QD in the internal organs of D. magna by inducing a reduced bioavailability. Results from this study revealed that NOM with relatively high hydrophobicity had a greater capability of inducing toxicity mitigation.     

Spinning Q-Balls for the Klein-Gordon-Maxwell Equations

The nonlinear Klein-Gordon-Maxwell equations provide models for the interaction between the electromagnetic field and matter. We assume that the nonlinear term W is positive and W(0) = 0. This fact makes the theory more suitable for physical models (for example models in supersymmetry theory and in cosmology; see e.g. [16, 22, 28] and their references).     

Exact solutions in gravity with a sigma model source

We consider a D-dimensional model of gravity with non-linear “scalar fields” as a matter source. The model is defined on the product manifold M, which contains n Einstein factor spaces. General cosmological type solutions to the field equations are obtained when n − 1 factor spaces are Ricci-flat, e.g. when one space M ₁ of dimension d ₁ > 1 has nonzero scalar curvature. The solutions are defined up to solutions to geodesic equations corresponding to a sigma model target space. Several examples of sigma models are presented. A subclass of spherically symmetric solutions is studied and a restricted version of “no-hair theorem” for black holes is proved. For the case d ₁ = 2 a subclass of latent soliton solutions is singled out.     

Nanometric size control and treatment of historic paper manuscript and prints with laser light at 157 nm

Laser cleaning of historic paper infected by foxing is far more effective at 157 nm than in other laser wavelengths because at 157 nm localized photo-dissociation of organic matter is taking place at low laser energy. In addition spatial control over exposed areas with resolution better than 100 nm is possible at this wavelength. In order to optimize the methods of laser cleaning of historic paper, foxing ablation experiments at 157 nm indicate that infected paper areas can be removed with controllable spatial resolution in the nanometer scale. In addition foxing samples were investigated by scanning electron microscopy and X-ray analysis. It was found that biological activity was present on paper areas containing traces of iron. PACS  87.50.Hj; 42.62.-b; 87.15.Mi     

SCQGP in quark stars

From an analogy with non-relativistic degenerate QED plasma we make an estimate of the coupling strength of QGP hypothesized to be present in compact star interiors. At densities ranging from 3ρ ₀–10ρ ₀ (normal nuclear density ρ ₀=0.16 fm⁻³), quark matter is found to be strongly to intermediately coupled. The equation of state for QED plasma obtained via Pade approximation, modified to QGP, yields stable stellar sequences with maximum mass ≳2M _⊙ for B ^1/4≲215 MeV.     

Extending the Fast Multipole Method for Charges inside a Dielectric Sphere in an Ionic Solvent: High Order Image Approximations for Reaction Fields

As a sequel to our previous paper on extending the Fast Multipole Method (FMM) for charges inside a dielectric sphere [J. Comput. Phys. 223 (2007) 846–864], this paper further extends the FMM to the electrostatic calculation for charges inside a dielectric sphere immersed in an ionic solvent, a scenery with more relevance in biological applications. The key findings include two fourth-order multiple discrete image approximations in terms of u = λa to the reaction field induced by the ionic solvent, provided that u = λa < 1 where λ is the inverse Debye screening length of the ionic solvent and a is the radius of the dielectric sphere. A 10⁻⁴ relative accuracy in the reaction field of a source charge within the sphere can be achieved with only 3–4 point image charges. Together with the image charges, the FMM can be used to speed up the calculation of electrostatic interactions of charges in a dielectric sphere immersed in an ionic solvent.     

Motor coordination deficits in Alpk1 mutant mice with the inserted piggyBac transposon

Background  

ALPK1 (α-kinase 1) is a member of an unconventional alpha-kinase family, and its biological function remains largely unknown. Here we report the phenotypic characterization of one mutant line, in which the piggyBac (PB) transposon is inserted into the Alpk1 gene.     

Bulk Viscous Bianchi Type I Cosmological Models with Time-Dependent Cosmological Term Λ

Bianchi type I cosmological models with time-varying cosmological constant Λ and bulk viscous fluid are investigated. Cosmic matter is chosen to obey a barotropic equation of state. Exact solutions of Einstein’s field equations are obtained assuming the volume expansion θ proportional to the eigen values of shear tensor σ _ij . Physical and kinematical properties of the models are discussed considering bulk viscosity to be a power function of matter density.     

Higher-dimensional perfect fluids and empty singular boundaries

In order to find out whether empty singular boundaries can arise in higher dimensional Gravity, we study the solution of Einstein’s equations consisting in a (N + 2)-dimensional static and hyperplane symmetric perfect fluid satisfying the equation of state ρ = ηp, being η an arbitrary constant and N ≥ 2. We show that this spacetime has some weird properties. In particular, in the case η > −1, it has an empty (without matter) repulsive singular boundary. We also study the behavior of geodesics and the Cauchy problem for the propagation of massless scalar field in this spacetime. For η > 1, we find that only vertical null geodesics touch the boundary and bounce, and all of them start and finish at z = ∞; whereas non-vertical null as well as all time-like ones are bounded between two planes determined by initial conditions. We obtain that the Cauchy problem for the propagation of a massless scalar field is well-posed and waves are completely reflected at the singularity, if we only demand the waves to have finite energy, although no boundary condition is required.     

Density perturbation of unparticle dark matter in the flat Universe

The unparticle has been suggested as a candidate of dark matter. We investigated the growth rate of the density perturbation for unparticle dark matter in the flat Universe. First, we consider the model in which the unparticle is the sole dark matter and find that the growth factor can be approximated well by f=(1+3ω _u )Ω _u ^γ , where ω _u is the equation of state of unparticle. Our results show that the presence of ω _u modifies the behavior of the growth factor f. For the second model where the unparticle co-exists with cold dark matter, the growth factor has a new approximation f=(1+3ω _u )Ω _u ^γ +α Ω _m and α is a function of ω _u . Thus the growth factor of the unparticle is quite different from that of the usual dark matter. This information can help us know more about unparticle and the early evolution of the Universe.     

Irradiation damage to frog inner ear during synchrotron radiation tomographic investigation

Unexpectedly severe radiation damage, showing up through deformation of the saccule, was encountered during a synchrotron radiation high-resolution (700 nm pixel size) tomographic observation of an inner ear, fixed in a formaldehyde solution, of the frog Rana esculenta. The visible displacement of the edge of the otoconia-filled part of the saccule amounted to about 100 μm after an irradiation with 20.5 keV X-ray photons corresponding to a dose of 1.5 kGy for the protein matrix. The close-knit coexistence of organic and mineral components in the biological tissue may be linked to the dramatic increase of radiation dosage sensitivity.