Making on-line science course materials easily translatable and accessible worldwide: Challenges and solutions

The PhET Interactive Simulations Project recently partnered with the Excellence Center of Science and Mathematics Education at King Saud University with the joint goal of making simulations available worldwide. One of the main challenges of this partnership is to make PhET simulations easily translatable so that truly anyone with a computer can use them in their classroom. The PhET project team has created the Translation Utility that allows a person, who is fluent in both English and another language, to easily translate any of the PhET simulations. This can be done with minimal computer expertise, making the translation process accessible to faculty and teachers. In this presentation we will share solutions to many of the unexpected problems we encountered that would apply in general to on-line scientific course materials including working with a language that is written right-to-left, different character sets, possible misconceptions and various conventions for expressing equations, variables, units and scientific notation

Synergistic Actions of Hematopoietic and Mesenchymal Stem/Progenitor Cells in Vascularizing Bioengineered Tissues

Poor angiogenesis is a major road block for tissue repair. The regeneration of virtually all tissues is limited by angiogenesis, given the diffusion of nutrients, oxygen, and waste products is limited to a few hundred micrometers. We postulated that co-transplantation of hematopoietic and mesenchymal stem/progenitor cells improves angiogenesis of tissue repair and hence the outcome of regeneration. In this study, we tested this hypothesis by using bone as a model whose regeneration is impaired unless it is vascularized. Hematopoietic stem/progenitor cells (HSCs) and mesenchymal stem/progenitor cells (MSCs) were isolated from each of three healthy human bone marrow samples and reconstituted in a porous scaffold. MSCs were seeded in micropores of 3D calcium phosphate (CP) scaffolds, followed by infusion of gel-suspended CD34+ hematopoietic cells. Co-transplantation of CD34+ HSCs and CD34− MSCs in microporous CP scaffolds subcutaneously in the dorsum of immunocompromized mice yielded vascularized tissue. The average vascular number of co-transplanted CD34+ and MSC scaffolds was substantially greater than MSC transplantation alone. Human osteocalcin was expressed in the micropores of CP scaffolds and was significantly increased upon co-transplantation of MSCs and CD34+ cells. Human nuclear staining revealed the engraftment of transplanted human cells in vascular endothelium upon co-transplantation of MSCs and CD34+ cells. Based on additional in vitro results of endothelial differentiation of CD34+ cells by vascular endothelial growth factor (VEGF), we adsorbed VEGF with co-transplanted CD34+ and MSCs in the microporous CP scaffolds in vivo, and discovered that vascular number and diameter further increased, likely owing to the promotion of endothelial differentiation of CD34+ cells by VEGF. Together, co-transplantation of hematopoietic and mesenchymal stem/progenitor cells may improve the regeneration of vascular dependent tissues such as bone, adipose, muscle and dermal grafts, and may have implications in the regeneration of internal organs

Hard Tissue Engineering

Peer reviewe

Stem Cell Therapy: Pieces of the Puzzle

Acute ischemic injury and chronic cardiomyopathies can cause irreversible loss of cardiac tissue leading to heart failure. Cellular therapy offers a new paradigm for treatment of heart disease. Stem cell therapies in animal models show that transplantation of various cell preparations improves ventricular function after injury. The first clinical trials in patients produced some encouraging results, despite limited evidence for the long-term survival of transplanted cells. Ongoing research at the bench and the bedside aims to compare sources of donor cells, test methods of cell delivery, improve myocardial homing, bolster cell survival, and promote cardiomyocyte differentiation. This article reviews progress toward these goals

Interrelationship between Dental Development, Skeletal Maturity and Chronological Age in Saudi Male Children.

Assessment of skeletal maturity and dental development is a common clinical practice in many health professions. Aims of this investigation were: 1) to test the applicability of the Demirjian46 method for dental age assessment and Greulich and Pyle47 atlas method for assessment of skeletal maturity to the Saudi male children; 2) to study the relationship between dental development, skeletal maturity and chronological age in Saudi male children; and 3) to study the association between the dental maturity markers and the skeletal maturity stages in Saudi male children. Materials and Methods: The sample consisted of panoramic and hand-wrist radiographs of 148 Saudi male children between 9 and 15 years of age. Demirjian46 method was used to estimate the dental age through the assessment of different calcification stages of the left mandibular dentition. Skeletal age was determined using Greulich and Pyle47 atlas and skeletal maturity stage was established utilizing Björk’s21 skeletal maturity indicators. Results: Paired sample T-test revealed no significant difference between the mean dental, skeletal and chronological age. Tendency toward late skeletal maturation and early dental maturation was observed. Spearman rank order test showed high correlation between skeletal maturity markers and dental maturity markers of the 1st premolar (r=0.729) and 2nd molar (r=0.720). Conclusion: chronological age is a reasonable indicator of the dental and skeletal maturation in Saudi male children. The dental maturation stage of the left mandibular 1st premolar and 2nd molar can be used to predict the skeletal maturity stage in Saudi male children. The skeletal maturity rate of Saudi male children is analogous to previously reported rates in other groups with different ethnic backgrounds.King Saud Universit