Ultrasonic Laboratory Study of Full Waveform Acoustic Logs in Boreholes with Fractures

A set of ultrasonic experiments was carried out to determine the effects of horizontal and vertical fractures on full waveform acoustic logs. Boreholes of 1 cm diameter were drilled in aluminum blocks. Measurements were made with horizontal fractures of 0.05 mm, 1.0 mm, 2.5 mm, and 4.5 mm width and a vertical fracture of 1.0 mm width. The horizontal fractures of even the smallest thickness significantly attenuate the P, S, and pseudo-Rayleigh waves. The Stoneley waves are the least attenuated, and attenuation increases with increasing fracture width. The vertical fracture attenuates Stoneley waves most significantly. Both scattering and fluid flow playa role in attenuation. The results may qualitatively be extended to inclined open fractures, where we expect strong attenuation of P and S waves and moderate attenuation of Stoneley waves.Massachusetts Institute of Technology. Full Waveform Acoustic Logging Consortiu

High precision determination of the Q2Q^2-evolution of the Bjorken Sum

We present a significantly improved determination of the Bjorken Sum for 0.6$\leq Q^{2}\leq$4.8 GeV$^{2}$ using precise new $g_{1}^{p}$ and $g_{1}^{d}$ data taken with the CLAS detector at Jefferson Lab. A higher-twist analysis of the $Q^{2}$-dependence of the Bjorken Sum yields the twist-4 coefficient $f_{2}^{p-n}=-0.064 \pm0.009\pm_{0.036}^{0.032}$. This leads to the color polarizabilities $\chi_{E}^{p-n}=-0.032\pm0.024$ and $\chi_{B}^{p-n}=0.032\pm0.013$. The strong force coupling is determined to be \alpha_{s}^{\overline{\mbox{ MS}}}(M_{Z}^{2})=0.1124\pm0.0061, which has an uncertainty a factor of 1.5 smaller than earlier estimates using polarized DIS data. This improvement makes the comparison between $\alpha_{s}$ extracted from polarized DIS and other techniques a valuable test of QCD.Comment: Published in Phys. Rev. D. V1: 8 pages, 3 figures. V2: Updated references; Included threshold matching in \alpha_s evolution. Corrected a typo on the uncertainty for \Lambda_QCD. V3: Published versio

Características lexicas dos subdialectos cristãos do tatar

This article is devoted to lexical peculiarity study of baptized Tatar (Kryashens) dialects, an ethnoconfessional group of Tatars in the Volga and Ural regions living in the Republic of Tatarstan and neighboring republics and regions. Within the framework of lexical features, they analyzed the Turkic words that were outdated for the modern Tatar language, as well as the borrowings that took place in the dialects. The vocabulary of Kryashen dialects basically coincides with the common Tatar vocabulary, however there are specific features that distinguish these dialects from the Tatar literary language and its dialects. The presence of these features is conditioned by the relatively isolated development of the Kryashens from other ethnographic groups of the Tatar people. A rather large place in the dialects is occupied by words that occur in ancient Turkic language and in a number of modern Turkic and Finno-Ugric languages, for example: arıw / aru - 'saint; good; clean', ardaqlı - 'esteemed', küz - 'burning coal, fire', pıçu/peçü - 'to cut', etc. The work also examines the borrowings, most of which are Russian words, and Arab-Persian, Chuvash and Udmurt borrowings are used less. Examples are given for each group and the features of their application are determined.Este artículo está dedicado al estudio de la peculiaridad léxica de los dialectos tártaros bautizados (Kryashens), un grupo etnoconfesional de tártaros en las regiones del Volga y los Urales que viven en la República de Tatarstán y en las repúblicas y regiones vecinas. En el marco de las características léxicas, se analizaron las palabras turcas que estaban desactualizadas para la lengua tártara moderna, así como los préstamos que tuvieron lugar en los dialectos. El vocabulario de los dialectos de Kryashen básicamente coincide con el vocabulario tártaro común, sin embargo, hay características específicas que distinguen a estos dialectos del lenguaje literario tártaro y sus dialectos. La presencia de estas características está condicionada por el desarrollo relativamente aislado de los Kryashens de otros grupos etnográficos del pueblo tártaro. Un lugar bastante grande en los dialectos está ocupado por palabras que ocurren en la lengua turca antigua y en varias lenguas turcas y finouguras modernas, por ejemplo: arıw / aru - 'saint; bueno; clean ', ardaqlı -' estimado ', küz -' quema de carbón, fuego', pıçu / peçü -' cortar', etc. El trabajo ademas examina los préstamos, la mayoría de los cuales son palabras rusas, y árabepersa, Chuvash y los préstamos Udmurt se usan menos. Se dan ejemplos para cada grupo y se determinan las características de su aplicación.Este artigo é dedicado ao estudo da peculiaridade lexical dos tártaros dialetos batizados (Kryashens), um grupo étnico-confessional de tártaros em regiões do Volga e dos Urais que vivem na República do Tartaristão e repúblicas e regiões vizinhas. No marco das características lexicais, analisaram as palavras turcas que estavam desatualizadas para a moderna língua tártara, bem como os empréstimos que ocorriam nos dialetos. O vocabulário dos dialetos de Kryashen basicamente corresponde ao vocabulário comum Tartar, no entanto, existem características específicas que distinguem estes dialetos de Tatar língua literária e seus dialetos. A presença dessas características é condicionada pelo desenvolvimento relativamente isolado dos Kryashens de outros grupos etnográficos do povo tártaro. Um lugar bastante grande nos dialetos é ocupado por palavras que ocorrem na antiga língua turca e em várias línguas e finuras turcas modernas, por exemplo: arıw / aru - 'saint; bom clean ', ardaqlı -' caro ', küz -' queima de carvão, fogo ', pıçu / peçü -' corte ', etc. O trabalho também examina os empréstimos, a maioria dos quais são palavras russas, e os empréstimos árabe-persa, chuvache e udmurto são usados menos. Exemplos são dados para cada grupo e as características de sua aplicação são determinadas

Nanomechanical characterization by double-pass force-distance mapping

Cataloged from PDF version of article.We demonstrate high speed force–distance mapping using a double-pass scheme. The topography is measured in tapping mode in the first pass and this information is used in the second pass to move the tip over the sample. In the second pass, the cantilever dither signal is turned off and the sample is vibrated. Rapid (few kHz frequency) force–distance curves can be recorded with small peak interaction force, and can be processed into an image. Such a double-pass measurement eliminates the need for feedback during force–distance measurements. The method is demonstrated on self-assembled peptidic nanofibers

A Spectroscopic Survey of a Sample of Active M Dwarfs

A moderate resolution spectroscopic survey of Fleming's sample of 54 X-ray selected M dwarfs with photometric distances less than 25 pc is presented. Radial and rotation velocities have been measured by fits to the H-alpha profiles. Radial velocities have been measured by cross correlation. Artificial broadening of an observed spectrum has produced a relationship between H-alpha FWHM and rotation speed, which we use to infer rotation speeds for the entire sample by measurement of the H-alpha emission line. We find 3 ultra-fast rotators (UFRs, vsini > 100km/s), and 8 stars with 30 < vsini < 100 km/s. The UFRs have variable emission. Cross-correlation velocities measured for ultra-fast rotators (UFRs) are shown to depend on rotation speed and the filtering used. The radial velocity dispersion of the sample is 17 km/s. A new double emission line spectroscopic binary with a period of 3.55 days has been discovered, and another known one is in the sample. Three other objects are suspected spectroscopic binaries, and at least six are visual doubles. The only star in the sample observed to have significant lithium is a known TW Hya Association member, TWA 8A. These results show that there are a number of young (< 10^8 yr) and very young (< 10^7 yr) low mass stars in the immediate solar neighbourhood. The H-alpha activity strength does not depend on rotation speed. Our fast rotators are less luminous than similarly fast rotators in the Pleiades. They are either younger than the Pleiades, or gained angular momentum in a different way.Comment: 38 pages incl. 14 figures and 4 tables, plus 12 pages of table for electronic journal only; LaTeX, aastex.cls. Accepted 07/18/02 for publication in The Astronomical Journa

Precise determination of the deuteron spin structure at low to moderate Q(2) with CLAS and extraction of the neutron contribution

We present the final results for the deuteron spin structure functions obtained from the full data set collected in 2000-2001 with Jefferson Lab\u27s continuous electron beam accelerator facility (CEBAF) using the CEBAF large acceptance spectrometer (CLAS). Polarized electrons with energies of 1.6, 2.5, 4.2, and 5.8 GeV were scattered from deuteron ((ND3)-N-15) targets, dynamically polarized along the beam direction, and detected with CLAS. From the measured double-spin asymmetry, the virtual photon absorption asymmetry A(1)(d) and the polarized structure function g(1)(d) were extracted over a wide kinematic range (0.05 GeV2 \u3c Q(2) \u3c 5 GeV2 and 0.9 GeV \u3c W \u3c 3 GeV). We use an unfolding procedure and a parametrization of the corresponding proton results to extract from these data the polarized structure functions A(1)(n) and g(1)(n) of the (bound) neutron, which are so far unknown in the resonance region, W \u3c 2 GeV. We compare our final results, including several moments of the deuteron and neutron spin structure functions, with various theoretical models and expectations, as well as parametrizations of the world data. The unprecedented precision and dense kinematic coverage of these data can aid in future extractions of polarized parton distributions, tests of perturbative QCD predictions for the quark polarization at large x, a better understanding of quark-hadron duality, and more precise values for higher-twist matrix elements in the framework of the operator product expansion

Peptide-based materials for cartilage tissue regeneration

Cartilaginous tissue requires structural and metabolic support after traumatic or chronic injuries because of its limited capacity for regeneration. However, current techniques for cartilage regeneration are either invasive or ineffective for long-term repair. Developing alternative approaches to regenerate cartilage tissue is needed. Therefore, versatile scaffolds formed by biomaterials are promising tools for cartilage regeneration. Bioactive scaffolds further enhance the utility in a broad range of applications including the treatment of major cartilage defects. This chapter provides an overview of cartilage tissue, tissue defects, and the methods used for regeneration, with emphasis on peptide scaffold materials that can be used to supplement or replace current medical treatment options. © Springer International Publishing AG 2017

Heparin mimetic peptide nanofiber gel promotes regeneration of full thickness burn injury

Burn injuries are one of the most common types of trauma worldwide, and their unique physiology requires the development of specialized therapeutic materials for their treatment. Here, we report the use of synthetic, functional and biodegradable peptide nanofiber gels for the improved healing of burn wounds to alleviate the progressive loss of tissue function at the post-burn wound site. These bioactive nanofiber gels form scaffolds that recapitulate the structure and function of the native extracellular matrix through signaling peptide epitopes, which can trigger angiogenesis through their affinity to basic growth factors. In this study, the angiogenesis-promoting properties of the bioactive scaffolds were utilized for the treatment of a thermal burn model. Following the excision of necrotic tissue, bioactive gels and control solutions were applied topically onto the wound area. The wound healing process was evaluated at 7, 14 and 21 days following injury through histological observations, immunostaining and marker RNA/protein analysis. Bioactive peptide nanofiber-treated burn wounds formed well-organized and collagen-rich granulation tissue layers, produced a greater density of newly formed blood vessels, and exhibited increased re-epithelialization and skin appendage development with minimal crust formation, while non-bioactive peptide nanofibers and the commercial wound dressing 3M™ Tegaderm™ did not exhibit significant efficiency over sucrose controls. Overall, the heparin-mimetic peptide nanofiber gels increased the rate of repair of burn injuries and can be used as an effective means of facilitating wound healing. © 2017 Elsevier Lt

Intracellular Accumulation of Gold Nanoparticles Leads to Inhibition of Macropinocytosis to Reduce the Endoplasmic Reticulum Stress

Understanding the toxicity of nanomaterials remains largely limited to acute cellular response, i.e., short-Term in vitro cell-death based assays, and analyses of tissue-and organ-level accumulation and clearance patterns in animal models, which have produced very little information about how these materials (from the toxicity point of view) interact with the complex intracellular machinery. In particular, understanding the mechanism of toxicity caused by the gradual accumulation of nanomaterials due to prolonged exposure times is essential yet still continue to be a largely unexplored territory. Herein, we show intracellular accumulation and the associated toxicity of gold nanoparticles (AuNPs) for over two-months in the cultured vascular endothelial cells. We observed that steady exposure of AuNPs at low (non-lethal) dose leads to rapid intracellular accumulation without causing any detectable cell death while resulting in elevated endoplasmic reticulum (ER) stress. Above a certain intracellular AuNP threshold, inhibition of macropinocytosis mechanism ceases further nanoparticle uptake. Interestingly, the intracellular depletion of nanoparticles is irreversible. Once reaching the maximum achievable intracellular dose, a steady depletion is observed, while no cell death is observed at any stage of this overall process. This depletion is important for reducing the ER stress. To our knowledge, this is the first report suggesting active regulation of nanoparticle uptake by cells and the impact of long-Term exposure to nanoparticles in vitro. © 2017The Author(s)

Double Spin Asymmetries A_NN and A_SS at sqrt{s}=200 GeV in Polarized Proton-Proton Elastic Scattering at RHIC

We present the first measurements of the double spin asymmetries A_NN and A_SS at sqrt{s}=200 GeV, obtained by the pp2pp experiment using polarized proton beams at the Relativistic Heavy Ion Collider (RHIC). The data were collected in the four momentum transfer t range 0.01<|t|<0.03 (GeV/c)^2. The measured asymmetries, which are consistent with zero, allow us to estimate upper limits on the double helicity-flip amplitudes phi_2 and phi_4 at small t as well as on the difference Delta(sigma_T) between the total cross sections for transversely polarized protons with antiparallel or parallel spin orientations.Comment: 13 pages with 3 figures. Final version accepted by Phys. Lett.