Pigmented melanoma cell migration study on murine syngeneic B16F10 melanoma cells or tissue transplantation models

Melanoma is a lethal form of skin cancer with poor prognosis, especially due to the early metastatic feature. Recent studies have shown that the melanin pigment influences the nanomechanical properties and, therefore, the metastatic behavior of the melanoma cells. We aimed to study the growth of subcutaneously transplanted syngeneic melanoma tissue in female C57BL/6 mice harvested from a mouse with a four-week B16F10 melanoma. Also, we studied the effect of the melanin pigment loading on the peritumoral migratory abilities of melanoma cells. Even when the syngeneic transplant was different (cultured cells vs. tumor tissue), the morphological features and the tumor growth were similar in both groups of mice. Heavily pigmented melanoma cells had low migration abilities. Angiogenesis, the depigmentation phenomenon, and the cell shape changes were related to pigmented melanoma cell migration along the matrix collagen fibers of peritumoral structures: the abluminal face of the vessels (angiotropism), the endomysium, and the nerves (neurotropism). The replacement of the histopathological growth pattern, the absence of angiogenesis, and rapidly tumor-bearing emboli were correlated with amelanotic and low pigmented melanoma cells. This study demonstrated that syngeneic melanoma tissue transplantation was a viable technique, and that the melanin pigment loading level can affect the melanoma cell migration profile

Improved methods for detecting gravitational waves associated with short gamma-ray bursts

In the era of second generation ground-based gravitational wave detectors, short gamma-ray bursts (GRBs) will be among the most promising astrophysical events for joint electromagnetic and gravitational wave observation. A targeted search for gravitational wave compact binary merger signals in coincidence with short GRBs was developed and used to analyze data from the first generation LIGO and Virgo instruments. In this paper, we present improvements to this search that enhance our ability to detect gravitational wave counterparts to short GRBs. Specifically, we introduce an improved method for estimating the gravitational wave background to obtain the event significance required to make detections; implement a method of tiling extended sky regions, as required when searching for signals associated to poorly localized GRBs from Fermi Gamma-ray Burst Monitor or the InterPlanetary Network; and incorporate astrophysical knowledge about the beaming of GRB emission to restrict the search parameter space. We describe the implementation of these enhancements and demonstrate how they improve the ability to observe binary merger gravitational wave signals associated with short GRBs.Comment: 13 pages, 6 figure

On the scattering of longitudinal elastic waves from axisymmetric defects in coated pipes

This is the post-print version of the final paper published in Journal of Sound and Vibration. The published article is available from the link below. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. Copyright @ 2013 Elsevier B.V.Viscoelastic coatings are widely used to protect pipelines from their surrounding environment. These coatings are known to attenuate ultrasonic waves guided along the pipe walls, which may limit the range of a pulse/echo based inspection technique that seeks to detect defects in a pipeline. This article aims to investigate the attenuation of longitudinal modes in a coated pipe by comparing predicted and measured values for the reflection coefficient of an axisymmetric defect in a pipe coated with bitumen. This extends recent work undertaken by the authors for torsional modes, and also provides an independent investigation into the validity of those values proposed by the authors for the shear properties of bitumen, based on a comparison between prediction and experiment for torsional modes. Predictions are generated using a numerical mode matching approach for axially uniform defects, and a hybrid finite element based method for non-uniform defects. Values for the shear and longitudinal properties of bitumen are investigated and it is shown that the shear properties of the viscoelastic material play a dominant role in the propagation of longitudinal modes in a coated pipeline. Moreover, by using the shear values obtained from experiments on torsional modes, it is shown that good agreement between prediction and measurement for uniform and non-uniform defects may also be obtained for the longitudinal L(0,2) mode. This provides further validation for the shear bulk acoustic properties proposed for bitumen in the low ultrasonic frequency range, although in order to apply this methodology in general it is demonstrated that one must measure independently the reflection coefficient of both the torsional T(0,1) and the longitudinal L(0,2) mode before arriving at values for the shear properties of a viscoelastic material

Low pressure line shape study of nitrogen-perturbed acetylene transitions in the ν1 + ν3 band over a range of temperatures

International audienceSix nitrogen perturbed transitions of acetylene within the ν1+ν3 absorption band have been recorded using a 3-channel diode laser spectrometer. The goal being an improved understanding of both broadening and narrowing effects of low pressure acetylene under the influence of nitrogen gas. To this end we have examined C2H2 spectra using a hard collision Rautian profile over a range of five temperatures (213 K-333 K) and five pressures (5-40 Torr). From these fits we have obtained the N2- broadening and narrowing coefficients of C2H2 and examined their temperature dependence. The experimentally measured narrowing coefficients have been used to estimate the nitrogen diffusion coefficients (D12) and are presented within. The broadening coefficients and corresponding temperature dependence exponents have also been compared to that of calculations completed using a classical impact approach on an ab initio potential energy surface. We have observed a good agreement between our theoretical and experimental results. Utilisant un spectromètre à diode laser à trois canaux, nous avons enregistré six transitions dans l'acétylène perturbée par de l'azote à l'intérieur de la bande d'absorption ν1 + ν3. Le but est d'améliorer notre compréhension des mécanismes d'élargissement et de resserrement dans l'acétylène à basse pression en présence d'azote. À cette fin, nous avons étudié les spectres de C2H2 en utilisant un profil de Rautian de collisions dures pour cinq températures dans le domaine 213-333 K et cinq pressions dans le domaine 5-40 Torr. À partir ce ces ajustements numériques, nous avons obtenu les coefficients d'élargissement et de resserrement de C2H2 et avons examiné leur dépendance en température. Nous avons utilisé les valeurs obtenues expérimentalement pour les coefficients de resserrement afin d'estimer les coefficients de diffusion de l'azote (D12) et nous les présentons ici. Les coefficients d'élargissement et la dépendance en température sont aussi comparés aux résultats de calculs qui utilisent une approche de collisions classiques et une surface d'énergie potentielle obtenue de principes premiers. Nous observons un bon accord entre calculs théoriques et valeurs expérimentales

Study of the Structure and Antimicrobial Activity of Ca-Deficient Ceramics on Chlorhexidine Nanoclay Substrate

Novel biomedical composites, based on organically modified vermiculite and montmorillonite with deposited Ca-deficient hydroxyapatite (CDH), were prepared. The monoionic sodium forms of vermiculite and montmorillonite were intercalated with chlorhexidine diacetate (CA). The surfaces of organoclays were used for the precipitation of Ca-deficient hydroxyapatite. The composites with Ca-deficient hydroxyapatite showed very good antibacterial effects, similar to the antimicrobial activity of pure organoclay samples. Better antibacterial activity was shown in the organically modified montmorillonite sample with Ca-deficient hydroxyapatite compared with the vermiculite composite, but, in the case of Staphylococcus aureus, both composites showed the same minimum inhibitory concentration (MIC) value. The antimicrobial effect of composites against bacteria and fungi increased with the time of exposure. The structural characterization of all the prepared materials, performed using X-ray diffraction and FT infrared spectroscopy analysis, detected no changes in the original clay or CDH during the intercalation or precipitation process, therefore we expect the strength of the compounds to be in the original power.Web of Science1218art. no. 299

Antibacterial activity of silver-doped hydroxyapatite nanoparticles against gram-positive and gram-negative bacteria

Ag-doped nanocrystalline hydroxyapatite nanoparticles (Ag:HAp-NPs) (Ca(10-x)Ag(x)(PO(4))(6)(OH)(2), x(Ag) = 0.05, 0.2, and 0.3) with antibacterial properties are of great interest in the development of new products. Coprecipitation method is a promising route for obtaining nanocrystalline Ag:HAp with antibacterial properties. X-ray diffraction identified HAp as an unique crystalline phase in each sample. The calculated lattice constants of a = b = 9.435 Å, c = 6.876 Å for x(Ag) = 0.05, a = b = 9.443 Å, c = 6.875 Å for x(Ag) = 0.2, and a = b = 9.445 Å, c = 6.877 Å for x(Ag) = 0.3 are in good agreement with the standard of a = b = 9.418 Å, c = 6.884 Å (space group P6(3)/m). The Fourier transform infrared and Raman spectra of the sintered HAp show the absorption bands characteristic to hydroxyapatite. The Ag:HAp nanoparticles are evaluated for their antibacterial activity against Staphylococcus aureus, Klebsiella pneumoniae, Providencia stuartii, Citrobacter freundii and Serratia marcescens. The results showed that the antibacterial activity of these materials, regardless of the sample types, was greatest against S. aureus, K. pneumoniae, P. stuartii, and C. freundii. The results of qualitative antibacterial tests revealed that the tested Ag:HAp-NPs had an important inhibitory activity on P. stuartii and C. freundii. The absorbance values measured at 490 nm of the P. stuartii and C. freundii in the presence of Ag:HAp-NPs decreased compared with those of organic solvent used (DMSO) for all the samples (x(Ag) = 0.05, 0.2, and 0.3). Antibacterial activity increased with the increase of x(Ag) in the samples. The Ag:HAp-NP concentration had little influence on the bacterial growth (P. stuartii)

Experimental Air-Broadened Line Parameters in the nu2 Band of CH3D

In this study we report the first experimental measurements of air-broadening and air-induced pressure-shift coefficients for approximately 378 transitions in the nu2 fundamental band of CH3D. These results were obtained from analysis of 17 room temperature laboratory absorption spectra recorded at 0.0056 cm(exp -1) resolution using the McMath-Pierce Fourier transform spectrometer located on Kitt Peak, Arizona. Three absorption cells with path lengths of 10.2, 25 and 150 cm were used to record the spectra. The total sample pressures ranged from 0.129x10(exp -2) to 52.855x10(exp -2) atm with CH3D volume mixing ratios of approximately 0.0109 in air. The spectra were analyzed using a multispectrum non-linear least-squares fitting technique. We report measurements for air pressure-broadening coefficients for transitions with quantum numbers as high as J" = 20 and K = 15, where K" = K' equivalent to K (for a parallel band). The measured air broadening coefficients range from 0.0205 to 0.0835 cm(exp -1) atm(exp -1) at 296 K. All the measured pressure-shift coefficients are negative and are found to vary from about -0.0005 to -0.0080 cm(exp -1) atm(exp -1) at the temperature of the spectra. We have examined the dependence of the measured broadening and shift parameters on the J" and K quantum numbers and also developed empirical expressions to describe the broadening coefficients in terms of m (m = -J", J" and J" + 1 in the (sup Q)P- (sup Q)Q-, and (sup Q)R-branch, respectively) and K. On average, the empirical expressions reproduce the measured broadening coefficients to within 4.4%

Systematic investigation and in vitro biocompatibility studies on mesoporous europium doped hydroxyapatite

International audienceThis paper reports a systematic investigation on europium doped hydroxyapatite (Eu:HAp). In this work, a set of complementary techniques Fourier Transform Infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and, Brunauer-Emmett-Teller (BET) technique was used to allowing a proper understanding of Eu:HAp. The XPS analysis confirmed the substitution of Ca ions by Eu ions in Eu:HAp samples. Eu:HAp and pure HAp show the isotherms of type IV with a hysteresis loop at a relative pressure (P/P0) between 0.4 and 1.0, indicating the presence of mesopores. Finally, the in vitro biological effects of Eu:HAp nanoparticles were evaluated by focusing on F-actin filaments pattern and heat shock proteins (Hsp) expression in HEK293 human kidney cells. Fluorescence microscopy studies of the actin protein revealed no changes of the immunolabeling profile in the renal cells cultured in the presence of Eu:HAp nanoparticles. Hsp60, Hsp70 and Hsp90 expression measured by Western blot analysis were not affected after a 24 and 48 hours exposure. These results confirmed the lack of nanoparticles' toxicity and the biocompatibility of Eu:HAp nanoparticles and their possibility possible uses of using them in medical purposes without affecting the renal function

Multispectrum Analysis of 12CH4 in the v4 Band: I. Air-Broadened Half Widths, Pressure-Induced Shifts, Temperature Dependences and Line Mixing

Lorentz air-broadened half widths, pressure-induced shifts and their temperature dependences have been measured for over 430 transitions (allowed and forbidden) in the v4 band of (CH4)-12 over the temperature range 210 to 314 K. A multispectrum non linear least squares fitting technique was used to simultaneously fit a large number of high-resolution (0.006 to 0.01/cm) absorption spectra of pure methane and mixtures of methane diluted with dry air. Line mixing was detected for pairs of A-, E-, and F-species transitions in the P- and R-branch manifolds and quantified using the off-diagonal relaxation matrix elements formalism. The measured parameters are compared to air- and N2-broadened values reported in the literature for the v4 and other bands. The dependence of the various spectral line parameters upon the tetrahedral symmetry species and rotational quantum numbers of the transitions is discussed. All data used in the present work were recorded using the McMath-Pierce Fourier transform spectrometer located at the National Solar Observatory on Kitt Peak