Effects of calcitonin gene-related peptide on wound contraction in denervated and normal rat skin: a preliminary report

The aim of the present study was to observe the effect of calcitonin gene-related peptide (CGRP) on wound contraction in both denervated and normal areas. A total of 100 Wistar rats, each of which had a 2 x 2 cm full-thickness skin defect on the back, were divided into two main control groups and six corresponding experimental groups in which 10 x 10(-9) M and 10 x 10(-12) M synthetic rat CGRP were given intraperitoneally and intradermally. Contraction was assessed weekly with planimetry, and mean surface areas (mm2 +/- SD) of related groups were compared. Complete closure took 4 weeks for the normal control group and 8 weeks for the denervated control group (p < 0.05). The 10 x 10(-12) M CGRP with both types of application showed a decrease in the length of time for complete closure to 3 weeks in the normal experimental groups (p < 0.05), but complete closure still took 4 weeks in normal groups in which 10 x 10(-9) M CGRP was given (p < 0.05). Any dosage of CGRP given intraperitoneally showed no change in the closure period in the denervated experimental groups (p > 0.05). CGRP showed a trophic effect on healing by an increased rate of contraction in the rat model. However, the neural supply to the wound area seemed to be intact because of the necessity of axonal transfer of CGRP.     

Thermal performance analysis of a tube finned surface

The present work submits an experimental work on the heat transfer and friction loss characteristic, employing a tube finned heating surface kept at a constant temperature in a rectangular channel. The tube fins attached on the surface (o.d.=29 mm) were arranged as either in‐line or staggered. The parameters for the study were Reynolds number (3700–30 000), depending on hydraulic diameter, the distance between the tube fins in the flow direction (S_y/D=1.72–3.45) and the fin arrangement. The change in the Nusselt number with these parameters was determined. For both tube fin arrangements, it was observed that increasing Reynolds number increased Nusselt number, and maximum heat transfer occurred at S_y/D=2.59. Thermal performances for both arrangements were also determined and compared with respect to heat transfer from the same surface without fins. With staggered array, a heat transfer enhancement up to 25 per cent for S_y/D=3.45 in staggered array was achieved in constant pumping power. Copyright © 2002 John Wiley & Sons, Ltd.     

Pregnancy in dialysis-dependent women--the importance of frequent dialysis and collaborative care: a case report

An increasing number of successful pregnancies have been reported among women on chronic hemodialysis. Even with reduced fertility and high risk of complications, women of childbearing age receiving hemodialysis, should not be discouraged from pregnancy. Practitioners should be familiar with the effects of renal disease on pregnancy, consult patients about the possibility of pregnancy and its hazards and provide, if necessary, prompt surveillance and treatment. This paper describes the case of an unplanned but successful pregnancy of a woman receiving hemodialysis, emphasizing pregnancy management, mother's response evaluation, and infant growth.     

High-Transmission-Efficiency and Side-Viewing Micro OIDRS Probe for Fast and Minimally-Invasive Tumor Margin Detection

The determination of a cancer free margin I organs is a difficult and time consuming process, with an unmet need for rapid determination of tumor margin at surgery. In this paper, we report the design, fabrication and testing of a novel miniaturized optical sensor probe with "side-viewing" capability. Its unprecedented small size, unique "side-viewing" capability and high optical transmission efficiency enable the agile maneuvering and efficient data collection even in the narrow cavities inside the human body. The sensor probe consists of four micromachined substrates with optical fibers for oblique light incidence and collection of spatially resolved diffuse reflectance from the contacted tissues. The optical sensor probe has been used to conduct the oblique incidence diffuse reflectance spectroscopy (OIDRS) on a human pancreatic specimen. Based on the measurement results, the margin of the malignant tumor has been successfully determined optically, which matches well with the histological results.     

A comparison of basic dye adsorption onto zeolitic materials synthesized from fly ash

This investigation reveals the adsorption characteristics of two basic dyes, thionine (TH) and safranine T (ST), onto fly ash (FA) and its three zeolitized products prepared at different hydrothermal conditions. Typical two-step isotherms were observed for TH adsorption onto four adsorbents, whereas the isotherms of the larger ST molecules were S-shaped. The adsorption capacities of the zeolitized fly ash (ZFA) estimated from the first plateau region of the TH isotherms was nearly twice the FA capacity. The capacities increased by up to five times in the second plateau region. The adsorption capacity of FA for ST is equivalent that of TH, whereas the capacities of ZFA are lower than those found for TH. The equilibrium results were well-described by the Freundlich isotherm model. The kinetic data obtained in the temperature range of 298-318 K was analyzed using Paterson's and Nernst Plank's approximations based on the homogeneous surface diffusion model (HSDM). The thermodynamic functions for the transition state were evaluated from the temperature-dependence of the surface diffusion coefficients by applying the Eyring model.     

Effect of commercial purity levels on the mechanical properties of ultrafine-grained titanium

Two grades of commercial purity (CP) titanium (grades 2 and 4) were processed using equal-channel angular extrusion (ECAE) at 300 °C and 450 °C, respectively. The processing temperatures were the minimum temperatures at which eight pass ECAE could be performed without any shear-localization. The coarse-grained (CG) microstructures of as-received grade-2 and grade-4 CP-Ti, with average grain sizes of 110 μm and 70 μm, respectively, were refined down to sub-micron levels with a mean grain size of about 300 nm for both grades after 8 ECAE passes. The ultrafine-grained (UFG) microstructures led to substantial enhancement in strength for both grades. The grade-2 sample showed a more than two fold increase in yield strength (σ_y), from 307 MPa for the as-received one to about 620 MPa for the processed samples. The grade-4 CP-Ti exhibited a relatively smaller increase in strength due to the higher processing temperature, and it showed about 50% increase in σ_y after eight pass ECAE, from 531 to 758 MPa. These strength levels were obtained with high ductility levels of 21% and 25% for UFG grade-2 and grade-4 Ti, respectively. These improvements in mechanical properties are attributed to the substantially refined grain size and increased dislocation density. Grade-4 Ti is stronger than grade-2 because of the higher oxygen content. The higher ductility and significantly higher strain hardening capability of UFG grade-4 Ti, in spite of the similar grain size and microstructure with UFG grade-2 Ti, is also due to the higher impurity content, probably resulting in a higher dislocation storage capability during room temperature deformation, and thus, higher strain hardening capacity. Such properties make UFG grade-4 Ti comparable to the commercial Ti-6Al-4V alloy for biomedical applications without negative effects of the alloying elements on biocompatibility.     

Cross wedge rolling of a Ti6Al4V (ELI) alloy: the experimental studies and the finite element simulation of the deformation and failure

The cross wedge rolling (CWR) deformation and fracture of a Ti6Al4Al (ELI) alloy were investigated experimentally and numerically using a coupled thermo-mechanical finite element model analysis. The experimentally determined flow stress and damage model parameters were verified by tension split Hopkinson pressure bar testing of notched samples. The simulation and experimental CWR forces showed well agreements except near the end of the stretching zone. The model analysis showed that the temperature distribution in the work piece was non-uniform during the CWR. When the initial temperature of the work piece was relatively low, the work piece temperature increased, a heating effect of the plastic deformation, while relatively high initial work piece temperatures resulted in cooling the work piece, caused by the work piece contact with the tools. The cracks were shown numerically to initiate in the midsections of the work piece during the guiding action and elongated in a direction normal to the maximum tensile stress triaxiality, resulting in cruciform-shaped crack formation, which was well agreed with the previously observed crack shape.     

Tool allocation in flexible manufacturing systems with tool alternatives

In this paper, a heuristic approach for tool selection in flexible manufacturing systems (FMS) is presented. The proposed approach utilizes the ratio of tool life over tool size (L/S) for tool selection and allocation. The proposed method selects tool types with high L/S ratios by considering tool alternatives for the operations assigned to each machine. The performance of the method is demonstrated in sample problems as static examples, as well as in a simulation study for further analysis. This study also presents a survey of several approaches related to loading and tool allocation problems in FMS, highlights the importance of tooling, and discusses the practical aspects of tool-oriented decision-making. An extended framework, which expands on the L/S concept, is also presented.     

Strain analysis of the GaN epitaxial layers grown on nitridated Si(111) substrate by metal organic chemical vapor deposition

The strain analysis of GaN film on nitridated Si(111) substrate with different growth times between 0 and 660 s via metal organic chemical vapor deposition (MOCVD) was conducted based on the precise measurement of the lattice parameters by using high-resolution X-ray diffraction (HR-XRD). The nitridation time (NT) was changed at a fixed growth condition. The a- and c-lattice parameters were measured, followed by the in-plane and out-of-plane strains. Then, the biaxial and hydrostatic components were extracted from the total strain values obtained, and were then discussed in the present study as functions of the NT. The biaxial strain and stress are also strongly affected by the non-uniformity of the SiN_x buffer layer thickness.