ALISS: Advanced Linear Scheduling System

The line of balance (LOB) method is not widely used in the construction industry even though it has distinct advantages in repetitive construction projects. Attempts were made in the past to develop LOB systems but no system has met with universal acceptance because of a multitude of problems. As a response, a tool named ALISS was developed that solves most of the problems associated with LOB applications. ALISS is an acronym for Advanced Linear Scheduling System and makes use of a model that utilises the tools of information technology to the fullest extent. This is accomplished by creating a system that has a standalone and a web-based version. ALISS is programmed using Visual Basic and Visual Basic Script languages. It utilises MS Access and SQL server as a data repository. The resulting Advanced Linear Scheduling System not only accommodates all LOB requirements but also provides the latest technological developments as an embedded tool.Linear scheduling, repetitive construction, line of balance,

Effect of static magnetic field on experimental dermal wound strength

Context: An animal model. Aim: We sought to evaluate the effect of static magnetic fields on cutaneous wound healing. Materials and Methods: Male Wistar rats were used. Wounds were created on the backs of all rats. Forty of these animals (M group) had NeFeB magnets placed in contact with the incisions, either parallel (Pa) and perpendicular (Pr) to the incision. The other 40 animals (sham [S] group) had nonmagnetized NeFeB bars placed in the same directions as the implanted animals. Half of the animals in each group were killed and assessed for healing on postoperative day 7 and the other half on postoperative day 14. The following assessments were done: gross healing, mechanical strength, and histopathology. Statistical Analysis Used: Intergroup differences were compared by using the Mann-Whitney U or t test. Values for P less than 0.05 were accepted as significant. Results and Conclusions: There were no differences between the magnetic and sham animals with respect to gross healing parameters. The mechanical strength was different between groups. On postoperative day 14, the MPr14 had significantly higher scores than the other groups. When static, high-power, magnetic fields are placed perpendicular to the wound, increased wound healing occurs in the skin of the experimental model

Early weight bearing of porous HA/TCP (60/40) ceramics in vivo: A longitudinal study in a segmental bone defect model of rabbit

Porous interconnected hydroxyapatite (HA) and HA/tricalcium phosphate (TCP) (60/40) ceramics are promising materials for hard tissue repair. However, the mechanical properties of these materials have not been accurately determined under weight-bearing conditions. In this study, newly developed HA and HA/TCP (60/40) ceramics were used with intramedullary fixation in segmental bone defects of rabbits. Early radiological, histological, densitometric and biomechanical changes were evaluated. The mean radiological grade of healing and bonding to bone was higher in HA/TCP (60/40) ceramics than that of pure HA ceramics but the difference was not statistically significant. The densities of both implanted ceramics improved with time, supported by the histological evaluation of bone matrix ingrowth into ceramic pores, whereas the densities at the bone-ceramic interface decreased gradually. Flexural resonant frequencies and three-point bending strength increased, revealing an increase in mechanical stability during this early critical time interval where implant and/or bone-implant interface failures occur frequently. It can be concluded that both HA and HA/TCP (60/40) ceramics have a limited application in the treatment of load-bearing segmental bone defects but did not fail at the early stages of implantation. (C) 2007 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved

Biomechanical and histological comparison of the influence of oestrogen deficient state on tendon healing potential in rats

Thirty-six female Sprague-Dawley rats were divided into two groups: oophrectomised (oestrogen deficient) rats and sham operated (oestrogen maintained) rats. Rats were sacrificed at six, ten, and 14 weeks. The rats were randomly chosen to have biomechanical evaluation on one side and histological evaluation on the other. Biomechanical testing was performed on an Instron machine to measure peak load. Histological sections were evaluated for cell proliferation, collagen-fibre organisation, fibroblast density, angiogenesis, inflammatory cells, chondroid and osseous metaplasia. Compared with the sham operated group, the oophrectomised group showed a lesser average maximum stress (42.9 N/m2 versus 33.7 N/m2) at six weeks, which was significant (p < .05). Succeeding weeks showed no significant biomechanical differences between the two groups. The sham operated group showed greater inflammatory response, which was statistically significant (p < 0.05), and also revealed greater cell proliferation and density. The results of this study revealed that endogenous oestrogen may improve healing of the Achilles tendon in rats