No abstract

Brief behavioral activation and problem-solving therapy for depressed breast cancer patients: Randomized trial.

This paper describes the Kidney Disease Quality of Life (KDQOL) Instrument (dialysis version), a self-report measure that includes a 36-item health survey as the generic core, supplemented with multi-item scales targeted at particular concerns of individuals with kidney disease and on dialysis (symptom/problems, effects of kidney disease on daily life, burden of kidney disease, cognitive function, work status, sexual function, quality of social interaction, sleep). Also included were multi-item measures of social support, dialysis staff encouragement and patient satisfaction, and a single-item overall rating of health. The KDQOL was administered to 165 individuals with kidney disease (52% female; 48% male; 47% White; 27% African-American; 11% Hispanic; 8% Asian; 4% Native American; and 3% other ethnicities), sampled from nine different outpatient dialysis centres located in Southern California, the Northwest, and the Midwest. The average age of the sample was 53 years (range from 22 to 87), and 10% were 75 years or older. Internal consistency reliability estimates for the 19 multi-item scales exceeded 0.75 for every measure except one. The mean scores for individuals in this sample on the 36-item health scales were lower than the general population by one-quarter (emotional well-being) to a full standard deviation (physical function, role limitations due to physical health, general health), but similar to scores for dialysis patients in other studies. Correlations of the KDQOL scales with number of hospital days in the last 6 months were statistically significant (p < 0.05) for 14 of the 19 scales and number of medications currently being taken for nine of the scales. Results of this study provide support for the reliability and validity of the KDQOL.

The extremely high melting point of many ceramics adds challenges to additive manufacturing as compared with metals and polymers. Because ceramics cannot be cast or machined easily, three-dimensional (3D) printing enables a big leap in geometrical flexibility. We report preceramic monomers that are cured with ultraviolet light in a stereolithography 3D printer or through a patterned mask, forming 3D polymer structures that can have complex shape and cellular architecture. These polymer structures can be pyrolyzed to a ceramic with uniform shrinkage and virtually no porosity. Silicon oxycarbide microlattice and honeycomb cellular materials fabricated with this approach exhibit higher strength than ceramic foams of similar density. Additive manufacturing of such materials is of interest for propulsion components, thermal protection systems, porous burners, microelectromechanical systems, and electronic device packaging.

Additive manufacturing enables fabrication of materials with intricate cellular architecture, whereby progress in 3D printing techniques is increasing the possible configurations of voids and solids ad infinitum. Examples are microlattices with graded porosity and truss structures optimized for specific loading conditions. The cellular architecture determines the mechanical properties and density of these materials and can influence a wide range of other properties, e.g., acoustic, thermal, and biological properties. By combining optimized cellular architectures with high-performance metals and ceramics, several lightweight materials that exhibit strength and stiffness previously unachievable at low densities were recently demonstrated. This review introduces the field of architected materials; summarizes the most common fabrication methods, with an emphasis on additive manufacturing; and discusses recent progress in the development of architected materials. The review also discusses important applications, including lightweight structures, energy absorption, metamaterials, thermal management, and bioscaffolds.

No abstract

Compressible media can mitigate impulsive loads due to their ability to absorb energy and lower the intensity of an impulse by extending its duration. A variety of cellular materials are currently used to protect persons or structures from impulsive loads in automotive, sporting, and defense applications. While foams are the most common energy absorption materials in use today, emerging capability to fabricate well-defined, ordered lattice structures offers opportunity to create new energy absorption materials with previously unachieved properties. [1] We use a novel approach to fabricate microlattices with a range of architectures and truss diameters in the 0.05->5 mm range. [2] Because the spatial configuration of voids and solid (referred to here as the cellular architecture) is not stochastic as in foams, microlattices offer much more control over their mechanical performance than other cellular materials. For example, the unit cell symmetry, truss angle, truss diameter, and node-to-node spacing can be controlled independently and the trusses can be solid or hollow. [3] Depending on the application, different performance characteristics are required of the energy absorbing material. The injury criterion, or damage threshold s th , determines the maximum allowable stress transmitted, s tr , through the energy absorber such that s tr < s th . For energy absorbers in direct contact with the human body the injury criteria is generally on the order of 1 MPa. [4,5] Safety standards often define limits on acceleration, e.g., 150 Gs at an impact velocity of 5.2 m s À1 for motorcycle helmets, [6] and the maximum acceleration is determined by the transmitted stress and the relevant mass by Newton's second law. Space limitations and light weight considerations typically call for a material with maximum energy absorption per unit volume and unit mass. These requirements call for a stress-strain performance with [*] Dr.

No abstract