A transient gaze

This document explores and questions notions of place, identity, and transformation caused by displacement

Validation and reproducibility of computerised cell-viability analysis of tissue slices

BACKGROUND: The identification of live cells using membrane integrity dyes has become a frequently used technique, especially with articular cartilage and chondrocytes in situ where tissue slices are used to assess cell recovery as a function of location. The development of a reproducible computerised method of cell evaluation would eliminate many variables associated with manual counting and significantly reduce the amount of time required to evaluate experimental results. METHODS: To validate a custom computerised counting program, intra-person and inter-person cell counts of nine human evaluators (three groups – unskilled, novice, and experienced) were compared with repeated pixel counts of the custom program on 15 digitised images (in triplicate) of chondrocytes in situ stained with fluorescent dyes. RESULTS: Results indicated increased reproducibility with increased experience within evaluators [Intraclass Correlation Coefficient (ICC) range = 0.67 (unskilled) to 0.99 (experienced)] and between evaluators [ICC = 0.47 (unskilled), 0.85 (novice), 0.93 (experienced)]. The computer program had perfect reproducibility (ICC = 1.0). There was a significant relationship between the average of the experienced evaluators results and the custom program results (ICC = 0.77). CONCLUSIONS: This study demonstrated that increased experience in cell counting resulted in increased reproducibility both within and between human evaluators but confirmed that the computer program was the most reproducible. There was a good correlation between the intact cell recovery determined by the computer program and the experienced human evaluators. The results of this study showed that the computer counting program was a reproducible tool to evaluate intact cell recovery after use of membrane integrity dyes on chondrocytes in situ. This and the significant decrease in the time used to count the cells by the computer program advocate its use in future studies because it has significant advantages

High-Temperature Flow Behavior of Ceramic Suspensions

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65999/1/j.1151-2916.2000.tb01534.x.pd

Cryoprotectant kinetic analysis of a human articular cartilage vitrification protocol

AbstractWe recently published a protocol to vitrify human articular cartilage and a method of cryoprotectant removal in preparation for transplantation. The current study’s goal was to perform a cryoprotectant kinetic analysis and theoretically shorten the procedure used to vitrify human articular cartilage. First, the loading of the cryoprotectants was modeled using Fick’s law of diffusion, and this information was used to predict the kinetics of cryoprotectant efflux after the cartilage sample had been warmed. We hypothesized that diffusion coefficients obtained from the permeation of individual cryoprotectants into porcine articular cartilage could be used to provide a reasonable prediction of the cryoprotectant loading and of the combined cryoprotectant efflux from vitrified human articular cartilage. We tested this hypothesis with experimental efflux measurements. Osteochondral dowels from three patients were vitrified, and after warming, the articular cartilage was immersed in 3 mL X-VIVO at 4 °C in two consecutive solutions, each for 24 h, with the solution osmolality recorded at various times. Measured equilibrium values agreed with theoretical values within a maximum of 15% for all three samples. The results showed that diffusion coefficients for individual cryoprotectants determined from experiments with 2-mm thick porcine cartilage can be used to approximate the rate of efflux of the combined cryoprotectants from vitrified human articular cartilage of similar thickness. Finally, Fick’s law of diffusion was used in a computational optimization to shorten the protocol with the constraint of maintaining the theoretical minimum cryoprotectant concentration needed to achieve vitrification. The learning provided by this study will enable future improvements in tissue vitrification

Evaluating intra- and inter-examiner reproducibility in histometric measurement: one-wall intrabony periodontal defects in beagle dogs

Purpose: Accurate and exact measurement is an important factor for generating meaningful results in any properly designed study. If all the participating examiners are able to yield similar results, it will be possible to evaluate the objective results of the study more easily and quickly. The purpose of this study was to evaluate the intra- and inter-examiner reproducibility of histometric measurements in the intrabony periodontal defect model. Methods: One wall intrabony defects were surgically created at the distal aspect of the second and the medial aspect of the fourth mandibular premolars in the right and left jaw quadrants in twenty beagle dogs and the defect sites received the following β-tri calcium phosphate, growth differentiation factor-0, growth differentiation factor-100 and sham surgery. Histometric analysis was performed after 8 weeks. Histometric parameters were recorded and repeated at three months interval by three examiners. Intra- and inter-examiner reproducibility was assessed. Results: Most parameters of all the groups showed high intra- and inter-examiner reproducibility. Parameters including defect height, bone regeneration height, cementum regeneration height, and formation of junctional epithelium yielded interexaminer correlation ${\geq}0.9$. The intra-examiner reproducibility showed a high result, over 0.9. Conclusions: Histometric evaluation of the one-wall intra-alveolar periodontal defect model showed high reproducibility not only for a single given examiner but also among the three examinersope

A MICROFLUIDIC MODEL FOR THE MIGRATION OF CHONDROCYTE UNDER PULSED ELECTROMAGNETIC FIELD

ABSTRACT Pulsed electromagnetic field (PEMF) treatment is a potentially non-invasive method for tissue engineering. In this paper, a theoretical model is established to simulate the regeneration of articular cartilage for Osteoarthritis by means of pulsed electromagnetic fields (PEMF). The electrical field, flow field, single particle motion and concentration field during the growth of chondrocyte are obtained by solving the theoretical model numerically, which accounts for cell distribution in the culture dish. The induced electric field strength can be numerically obtained by Maxwell's equation and then the potential distribution by the Poisson equation and Laplace equation. The chondrocytes can be driven to move once the electric field is built up. In the calculation of the flow field, the continuity and momentum equation are applied to obtain the bulk electroosmotic velocity field which will affect the motion of the charged cell due to viscous drag forces. The motion of a single particle can be obtained by the classic Newton's second law. In addition to a single particle, the concentration distribution of particles which indicates the migration of chondrocytes can be described by the conservation law of mass. Boundary conditions are required to solve these sets of equations numerically. A comparison between model results and actual experimental data for the growth and migration of chondrocytes is performed. The results presented here allow a better understanding of the role PEMF in the treatment of Osteoarthritis

Using a pharmacist-led educational tool to teach elementary and middle-school students in Lebanon about microbes, antibiotic use and antimicrobial resistance: A pilot study

Background: Teaching school students about antibiotic use and antimicrobial resistance (AMR) can shape their future behaviour to become antibiotic guardians. This study aims to assess the impact of a pharmacist-led educational tool in boosting knowledge of these topics at elementary and middle school educational stages. Methods: A prospective web-based cross-sectional pre-post study was conducted in Lebanese private schools from April 2020 to December 2021. Results: The results showed that the pharmacist-led intervention increased the general knowledge (p = 0.01) and understanding of microbes (junior versus senior, p = 0.003 versus p = 0.004). In middle school, the spread of infection (p < 0.001) and the AMR concept (p = 0.001) significantly changed post-test, while antibiotics use and AMR concept remained unchanged in elementary students. Conclusion: The successful learning impact of the educational tool designed and led by pharmacists shows their importance as antibiotic experts in influencing early pedagogic learning about antibiotics and AMR starting at the middle-school stage.Scopu