Delayed effect of denervation on wound contraction in rat skin

Neuronal supply in soft tissues may be an important part of cutaneous wound healing. In order to observe the effect of denervation on wound contraction, rectangular full-thickness skin defects were created on the dorsum of two groups of Wistar rats. In the experimental group (n = 20), spinal nerves corresponding to the area of the open wound (T11 to L2) were isolated and divided bilaterally. In the control group (n = 20), the same pairs of spinal nerves were dissected but left intact. Limits of denervation were verified by the pinprick test. Wound healing, which is primarily in the form of wound contraction in this model, was evaluated by tracing wound margins onto millimetric paper weekly. Wound contraction was delayed significantly in the experimental group (p < 0.05) at all follow-up periods when compared with the controls. Loss of neuropeptide secretion from the nerve endings in denervated tissues may be responsible for the retarded wound contraction, since neuropeptides are thought to exert trophic effects on skin wound healing.     

Determination of the relationship between uniaxial and triaxial swelling equations for clay bearing rocks

Design in swelling mediums is mostly based on uniaxial data since the standards proposed by the International Society for Rock Mechanics Commission on Swelling Rocks for uniaxial tests are in the form of recommendations, triaxial sets are not highly available; and there is no standard developed for triaxial tests. The main purpose of this study is to define the relationship between the uniaxial and the triaxial swelling equations and to predict the triaxial values using the uniaxial data. The other purpose of the study is to contribute to the development of the standards and to expand the data available in the literature about triaxial swelling behavior. Numerous uniaxial and triaxial swelling tests were performed on the samples from seven different locations, in Turkey, in a state of the art swelling laboratory. As a result of the determination of the triaxial swelling behavior of these samples, the relationships between the uniaxial and the triaxial swelling data for the individual samples as well as the whole set of samples are expressed by the equations derived from the statistical analyses.     

An eye-tracking study of how color coding affects multimedia learning

Color coding has been proposed to promote more effective learning. However, insufficient evidence currently exists to show how color coding leads to better learning. The goal of this study was to investigate the underlying cause of the color coding effect by utilizing eye movement data. Fifty-two participants studied either a color-coded or conventional format of multimedia instruction. Eye movement data were collected during the study. The results indicate that color coding increased retention and transfer performance. Enhancement of learning by color coding was due to efficiency of locating corresponding information between illustration and text. Color coding also attracted attention of learners to perceptually salient information.     

An enhanced analytical model for residual stress prediction in machining

The predictions of residual stresses are most critical on the machined aerospace components for the safety of the aircraft. In this paper, an enhanced analytic elasto-plastic model is presented using the superposition of thermal and mechanical stresses on the workpiece, followed by a relaxation procedure. Theoretical residual stress predictions are verified experimentally with X-ray diffraction measurements on the high strength engineering material of Waspaloy that is used critical parts such as in aircraft jet engines. With the enhanced analytical model, accurate residual stress results are achieved, while the computational time compared to equivalent FEM models is decreased from days to seconds.     

Dynamic Multicore Resource Management: A Machine Learning Approach

A machine learning approach to multicore resource management produces self-optimizing on-chip hardware agents capable of learning, planning, and continuously adapting to changing workload demands. This results in more efficient and flexible management of critical hardware resources at runtime.     

Fabrication and Characterization of Ceramic Foams Based on Silicon Carbide Matrix and Hollow Alumino-Silicate Spheres

Closed-cell foams were fabricated by incorporating two different grades of hollow alumino-silicate spheres (cenospheres) into a silicon carbide matrix. The matrix was formed by the pyrolysis of a preceramic polymer, and multiple polymer infiltration and pyrolysis (PIP) cycles were employed to minimize the open voids in the material. The physical, mechanical and thermal properties of the fabricated foams were characterized as functions of the number of reinfiltration cycles. The open- and closed-void volume fractions were determined by measurements of bulk and skeletal densities. Mechanical properties, including strength and modulus, were evaluated using four-point bend and compression tests. Finally, thermal properties of the material, including the coefficient of thermal expansion and the thermal conductivity, were determined using dilatometry and the laser-flash technique, respectively. This processing technique results in closed-cell syntactic foams with minimal porosity (∼2–4%), reasonable mechanical strength (∼30 MPa) and very low thermal conductivity (≤1 W/m·K). In this manner, this process can be used for the low-cost and net-shape fabrication of closed-cell silicon carbide-based syntactic foams for high-temperature applications.     

Reliability assessment of CMOS differential cross-coupled LC oscillators and a novel on chip self-healing approach against aging phenomena

In this paper, reliability of CMOS differential cross-coupled LC oscillators is examined, and a novel on chip aging detection and healing technique is developed to increase the lifetime of oscillator circuits. Aging causes degradation in several transistor parameters, such as threshold voltage, mobility, and transconductance. While these changes cause irregular timing characteristics and increased power consumption in digital circuits, the case is quite different for their analog counterparts. Analog circuits, especially nonlinear ones, show more deviations at the output due to parameter changes. In order to evaluate the aging effects on nonlinear analog circuits, two different oscillator structures (n-type and p-type) with 5 GHz oscillation frequency were designed using 0.13 μm technology. The phase noise analysis of fresh and aged oscillators was performed analytically and through simulations. Based on these analyses the robustness of oscillators was discussed. Finally, an on chip aging sensor and self recovery mechanism are proposed to increase the robustness of the CMOS LC oscillators.     

Optimization of Lip Contour Estimation

Developing algorithms based on lip con- tour estimation is a distinctive trend in lip segmentation which is the first step of visual speech recognition. In order to establish an optimized estimation of lip contour that is complex enough to describe the principal features of the lip but at the same time simple enough to be implemented, the selection of lip model, estimator as well as parame- ters for features of lips, including the horizontal length of snake of feature points and horizontal distance between these feature points will be optimized. Experimental result demonstrates that the optimized estimation method of lip contour provides more accurate and more stable results of lip segmentation.     

Cost and safety optimization of structural design specifications

The design of buildings, bridges, offshore platforms and other civil infrastructure systems is controlled by specifications whose purpose is to provide the engineering principles and procedures required for evaluating the safety of structural systems. The calibration of these codes and specifications is a continuous process necessary to maintain a safe national and global infrastructure system while keeping abreast of new developments in engineering principles, and data on new materials, and applied loads. The common approach to specification calibration is to use probabilistic tools to deal with the random behavior of materials and to account for the uncertainties associated with determining environmental and other load effects. This paper presents a procedure to calibrate load factors for a structural design specification based on cost and safety optimization. The procedure is illustrated by determining load factors that may be applicable for incorporation in a bridge design specification. Traditional code calibration procedures require a set of pre-determined safety levels that should be used as target values that each load combination case should satisfy. The procedure in this paper deduces the failure cost implied in present designs, and provides consistent safety levels for all load combination cases. For greater accuracy, load effects showing variance in time have been modeled by separating them into two random variables; time dependent r.v. (wind speed, vehicular loads, etc.) and time independent r.v. (modeling uncertainties). The total expected lifetime cost is used in the optimization to account for both initial construction cost and future equivalent failure costs.