Fabrication of nano/microfiber scaffolds using a combination of rapid prototyping and electrospinning systems

Tissue‐engineered scaffolds require an adequate three‐dimensional (3‐D) structure for cell growth and attachment. Solid freeform fabrication can provide the interconnected pore to induce the cell ingrowth, and electrospinning technique can make the nanofiber web with high surface for cell attachment. In this study, 3‐D polycaprolactone (PCL) scaffolds were fabricated using a rapid prototyping plotting system coupled with an electrospinning apparatus. Scanning electron micrographs showed that these hybrid scaffolds had a regular microfiber structure with interconnected pores and a nanofiber distribution appropriate for cell attachment. Scaffolds were seeded with MG63 cells for in vitro study and implanted in the tibia of rabbit for in vivo study. The resulting structure also facilitated cell adhesion, proliferation, and differentiation as evidenced by biochemical analyses and confocal microscopy. The hybrid scaffolds also exhibited good biocompatibility and osteoconductivity in animal studies. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers     

Slowly digestible sweetpotato flour: Preparation by heat-moisture treatment and characterization of physicochemical properties

The preparation and physicochemical characteristics of sweetpotato flour with increased slowly digestible starch (SDS) fraction were investigated under various heat-moisture treatment (HMT) conditions. The optimum conditions for preparing slowly digestible sweetpotato flour established using response surface methodology were moisture content of 22%, temperature of 103°C, and treatment time of 5.8 h. The highest SDS content in heat-moisture treated sweetpotato flour was 57.6%. The relative crystallinity of heat-moisture treated sweetpotato flour decreased, but the X-ray diffraction pattern maintained the A-type. The DSC of the heatmoisture treated flour showed a decreased gelatinization temperature range and gelatinization enthalpy compared with native one. The viscosity profiles and values changed significantly with HMT, resulting in a higher pasting temperature, decrease of the viscosity values, and no breakdown. It indicates that heat-moisture treated sweetpotato flour is more stable at high temperatures and shear rates than native one.     

An irregular frequency reuse scheme for cellular OFDMA systems

While conventional frequency reuse techniques need to allocate mutually exclusive frequency resources to adjacent cells, this paper proposes a technique for OFDMA systems to use pseudo‐random subchannel allocation patterns based on the preamble number. Although sophisticated cell planning is not required for the proposed technique, irregular frequency patterns can allow efficient interference avoidance and high data throughput. Copyright © 2010 John Wiley & Sons, Ltd.     

Open‐Ended Waveguide Antenna Using a Single Split‐Ring Resonator

This letter proposes an open‐ended waveguide antenna with a single split‐ring resonator. In contrast to the waveguide antennas incorporating multiple rings reported in a previous study, which exhibited narrow bandwidth, the proposed antenna uses only one ring to achieve broader bandwidth while keeping the aperture small. A single ring has a relatively low quality factor compared to multiple rings. The simulated and measured fractional bandwidth was 4.13% and 4.03%, respectively, which is much broader than the fractional bandwidth of about 1% demonstrated in a previous study. This simple technique can be used in many applications that require small apertures including near‐field probes and array elements.     

Evaluation of low-cost optical particle counters for monitoring individual indoor aerosol sources

Abstract

Low-cost optical particle counters (OPC) have gained increasing attention in recent years in exposure studies. Previous studies reported that the OPCs’ performance varies considerably with type of particles being measured; however, little information on their performance in monitoring common indoor aerosols is available. Given the significance of exposure to indoor aerosols and their associated adverse health effects, this experimental study investigates the performance of low-cost OPCs in monitoring individual aerosols that are commonly found indoors in a controlled chamber environment. Performances of four low-cost OPCs were examined under exposure to varying concentrations of biological (dust mite, pollen, cat, and dog fur) and non-biological (monodisperse silica and melamine resin) aerosols. Each particle sample was dispersed into the chamber using a computer-controlled syringe injection system, while size-resolved particle number concentrations were simultaneously measured by four low-cost OPCs (OPC N2, IC Sentinel, Speck, and Dylos) as well as a lab-grade reference sensor (AeroTrak). The study results showed measurable effects of particle size, particle type, and concentration on the low-cost OPC responses. Particle concentration had the most dominant effect on the linearity of low-cost sensors. Results also revealed that the sensor responses to four biological particles follow a similar pattern and converge to a linear line as the number concentration increases above 5?cm^?3. As for non-biological particles, the OPC responses were more varied depending on the particle type and size, especially in the concentration range <10?cm^?3. Calibration equations developed in this study provide baseline information for correcting low-cost OPC readings when utilized to measure concentrations of individual indoor aerosol sources.

Copyright © 2019 American Association for Aerosol Research     

Curve veering in outer-clamped annular plates subject to nonuniform in-plane force

The existence of curve veering phenomenon is investigated in outer-clamped annular plates subject to in-plane force. The perturbation and Galerkin's methods are employed to verify the existence qualitatively and quantitatively, respectively. From qualitative and quantitative analyses, it is found that the curve veering phenomenon may take place in outer-clamped annular plates under nonuniform in-plane force.     

Stereotypes of emotional expressiveness of Northerners and Southerners: A cross-cultural test of Montesquieu's hypotheses.

Montesquieu argued that residents of warmer climates are more emotionally expressive than those living in cooler ones. More than 2,900 college students from 26 countries completed a brief questionnaire assessing the degree to which they considered Northerners and Southerners within their own countries to be emotionally expressive. In addition, individuals rated themselves on their own degree of expressiveness. In partial confirmation of Montesquieu's hypothesis, it was found that large within-country North-South stereotypes exist. Especially in Old World countries, Northerners are viewed as less emotionally expressive than Southerners. Regression and other analyses revealed that self-ratings of expressiveness were, in fact, related to being from the South and to warmer mean temperatures. Several possible explanations for these effects are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The neuronal stem cell of the olfactory epithelium

Reviews and evaluates psychosocial treatments for attention deficit hyperactivity disorder (ADHD) in children and adolescents according to Task Force Criteria (Lonigan, Elbert, & Johnson, this issue). It is concluded that behavioral parent training and behavioral interventions in the classroom meet criteria for well-established treatments. Cognitive interventions do not meet criteria for well-established or probably efficacious treatments. Issues regarding the evaluative process are discussed and future directions for psychosocial treatment for ADHD are outlined.     

General circular permutation layout

In thegeneral circular permutation layout problem there are two concentric circles,C _in andC _out. There are a set ofn inner terminals onC _in and a set ofn outer terminals onC _out: terminalsi onC _in and _i onC _out are to be connected by means of a wire, where 1 i n. All wires must be realized in the interior ofC _out. Each wire can intersectC _in at most once and at mostK wires, for a fixedK, can pass between two adjacent inner terminals. A linear-time algorithm for obtaining a planar homotopy (single-layer realization) of an arbitrary instance of the general circular permutation layout problem, forK 0, is proposed. Previously,K = 1 has been studied. In this paper the algorithm is also extended to a more general problem, in which the number of wires allowed to pass between each pair of adjacent terminals onC _in may be different from pair to pair.The work of R. D. Lou and M. Sarrafzadeh was supported in part by the National Science Foundation under Grants MIP-8709074 and MIP-8921540. C. S. Rim, K. Nakajima, and S. Masuda's work was supported in part by the National Science Foundation under Grants MIP-8451510 and CDR-8803012 (Engineering Research Centers Program), and a grant from AT&T.