Absorption, scattering, and radiation force efficiencies in the longitudinal wave scattering by a small viscoelastic particle in an isotropic solid.

Analytical expressions of the absorption, scattering, and elastic radiation force efficiency factors are derived for the longitudinal plane wave scattering by a small viscoelastic particle in a lossless solid matrix. The particle is assumed to be much smaller than the incident wavelength, i.e., the so-called long-wavelength (Rayleigh) approximation. The efficiencies are dimensionless quantities that represent the absorbed and scattering powers and the elastic radiation force on the particle. In the quadrupole approximation, they are expressed in terms of contrast functions (bulk and shear moduli, and density) between the particle and solid matrix. The results for a high-density polyethylene particle embedded in an aluminum matrix agree with those obtained with the partial wave expansion method. Additionally, the connection between the elastic radiation force and forward scattering function is established through the optical theorem. The present results should be useful for ultrasound characterization of particulate composites, and the development of implanted devices activated by radiation force.

Scattering of a longitudinal Bessel beam by a sphere embedded in an isotropic elastic solid.

The scattering of a longitudinal Bessel beam of arbitrary order by a sphere embedded in an isotropic solid matrix is theoretically analyzed. The spherical inclusion can be made of a viscoelastic, elastic, or fluid-filled isotropic material. In the analysis, the absorbing, scattering, and extinction efficiency factors are obtained, e.g., the corresponding power per characteristic beam intensity per sphere's cross-section area. Furthermore, the extended optical theorem, which expresses the extinction efficiency in terms of an integral of the longitudinal scattering function is derived. Several features of zeroth- and first-order Bessel beams scattering in solids are illustrated considering a polymer adhesive (cured) sphere embedded in a stainless steel matrix. For instance, omnidirectional scattering can be achieved by choosing specific values of the half-cone angle of the Bessel beam, which is the beam's geometrical parameter. Additionally, it is demonstrated that mode suppression leads to lower absorption inside the inclusion when compared to plane wave scattering results.

Intercâmbio internacional nos cursos de graduação de enfermagem / International exchange in nursing undergraduate courses

Objetivo: analisar a produção científica sobre intercâmbios internacionais realizados por estudantes durante a graduação em Enfermagem. Método: trata-se de uma revisão integrativa realizada nas bases de dados Literatura Latino-americana e do Caribe em Ciências da Saúde, Medical Literature Analysis and Retrieval System Online e Cochrane Library no período de 1995 a 2015. Resultados: foram analisados 19 artigos, a maioria de natureza qualitativa, publicados nos Estados Unidos da América, Austrália e Brasil. Destaca-se que o intercâmbio possibilita o desenvolvimento profissional e pessoal do estudante. O idioma e choque cultural emergiram como desafios e barreiras. Quanto às atividades desenvolvidas, foram identificadas consultas de enfermagem, estágios em hospitais, visitas técnicas, participação em grupo de pesquisas e eventos científicos. Conclusões: os intercâmbios no campo da Enfermagem ainda se encontram incipientes, entretanto, trata-se de um fenômeno em expansão por estar atrelado aos efeitos da globalização e que precisam de mais investimentos governamentais e privados.

Objective: to analyze the scientific production on international exchanges experienced by studentsduring undergraduate nursing. Method: it is an integrative review of the literature performed bysearching in the Latin American and Caribbean Literature in Health Sciences, Medical LiteratureAnalysis and Retrieval System Online and Cochrane Library databases from 1995 to 2015. Results: itanalyzed 19 articles, most of qualitative studies, published in the United States of America, Australiaand Brazil. It is emphasized that the exchange allows the professional and personal development ofthe student. Language and cultural shock have emerged as challenges and barriers. Regarding theactivities developed, nursing appointments, hospital internships, technical visits, participation in a research group and scientific events were identified. Conclusions: nursing exchanges are stillincipient, but it is a phenomenon that is expanding because it is linked to the effects of globalizationand requires more government and private investments.

Acoustic radiation force and torque exerted on a small viscoelastic particle in an ideal fluid.

We provide a detailed analysis on the acoustic radiation force and torque exerted on a homogeneous viscoelastic particle in the long-wave limit (i.e. the particle radius is much smaller than the incident wavelength) by an arbitrary wave. We assume that the particle behaves as a linear viscoelastic solid, which obeys the fractional Kelvin-Voigt model. Simple analytical expressions for the radiation force and torque are obtained. The developed theory is used to describe the interaction of acoustic waves (traveling and standing plane waves, and zero- and first-order Bessel beams) in the MHz-range with polymeric particles, namely lexan, low-density (LDPE) and high-density (HDPE) polyethylene. We found that particle absorption is chiefly the cause of the radiation force due to a traveling plane wave and zero-order Bessel beam when the frequency is smaller than 5MHz (HDPE), 3.9MHz (LDPE), and 0.9MHz (lexan). Whereas in a standing wave field, the radiation force is mildly changed due to dispersion inside the particle. We also show that the radiation torque caused by a first-order Bessel beam varies nearly quadratic with frequency. These findings may enable new possibilities of particle handling in acoustophoretic techniques.

Lower Detection Probability of Avian Plasmodium in Blood Compared to Other Tissues.

We tested whether the probability of detecting avian haemosporidia (Plasmodium and Haemoproteus) using molecular techniques differs among blood, liver, heart, and pectoral muscle tissues. We used a paired design, sampling the 4 tissue types in 55 individuals of a wild South American suboscine antbird, the white-shouldered fire-eye (Pyriglena leucoptera). We also identified parasites to cytochrome b lineage. Detection probability was significantly lower in blood compared to the other 3 tissue types combined. Eight of 22 infections were not detected in blood samples; 4-7 infections were not detected in the other individual tissues. The same parasite lineage was recovered from different tissues.

Generalization of the extended optical theorem for scalar arbitrary-shape acoustical beams in spherical coordinates.

The extended optical theorem is generalized for scalar acoustical beams of arbitrary character with any angle of incidence interacting with an object of arbitrary geometric shape and size, and placed randomly in the beam's path with any scattering angle. Analytical expressions for the extinction, absorption, and scattering cross sections are derived, and the connections with the axial (i.e., along the direction of wave propagation) torque and radiation force calculations are discussed. As examples to illustrate the analysis for a viscoelastic object, the extinction, absorption, and scattering cross sections are provided for an infinite plane progressive wave, infinite nondiffracting Bessel beams, a zero-order spherical quasi-Gaussian beam, and a Bessel-Gauss vortex beam emanating from a finite circular aperture, which reduces to a finite high-order Bessel beam, a finite zero-order Bessel beam, and a finite piston radiator vibrating uniformly with appropriate selection of beam parameters. The similarity with the asymptotic quantum inelastic cross sections is also mentioned.

Axial acoustic radiation torque of a Bessel vortex beam on spherical shells.

The present paper investigates the interaction of an acoustic Bessel vortex beam centered on a viscoelastic polyethylene sphere and spherical shells filled with air or water immersed in nonviscous water and mercury, and the induced axial acoustic radiation torque (ART) resulting from the transfer of angular momentum. Closed-form series expansions for the axial ART are derived for the case of progressive, standing, and quasistanding waves. The ART is shown to be the result of acoustic absorption inside the particle's material. Numerical predictions shown in the form of two-dimensional (2D) plots illustrate the theory, and reveal new properties related to the ART of Bessel vortex beams. Potential applications are in particle rotation and manipulation. Other applications, such as the characterization of fluids from induced angular accelerations (produced by the ART) and containerless processing, may benefit from the analysis developed here.

Effect of acute and chronic GVHD on relapse and survival after reduced-intensity conditioning allogeneic transplantation for myeloma.

We evaluated the effect of acute and chronic GVHD on relapse and survival after allogeneic hematopoietic SCT (HSCT) for multiple myeloma using non-myeloablative conditioning (NMA) and reduced-intensity conditioning (RIC). The outcomes of 177 HLA-identical sibling HSCT recipients between 1997 and 2005, following NMA (n=98) or RIC (n=79) were analyzed. In 105 patients, autografting was followed by planned NMA/RIC allogeneic transplantation. The impact of GVHD was assessed as a time-dependent covariate using Cox models. The incidence of acute GVHD (aGVHD; grades I-IV) was 42% (95% confidence interval (CI), 35-49%) and of chronic GVHD (cGVHD) at 5 years was 59% (95% CI, 49-69%), with 70% developing extensive cGVHD. In multivariate analysis, aGVHD (≥ grade I) was associated with an increased risk of TRM (relative risk (RR)=2.42, P=0.016), whereas limited cGVHD significantly decreased the risk of myeloma relapse (RR=0.35, P=0.035) and was associated with superior EFS (RR=0.40, P=0.027). aGVHD had a detrimental effect on survival, especially in those receiving autologous followed by allogeneic HSCT (RR=3.52, P=0.001). The reduction in relapse risk associated with cGVHD is consistent with a beneficial graft-vs-myeloma effect, but this did not translate into a survival advantage.