Computer-assisted instructional design

In this paper we articulate an alternative approach to look at video games and learning to become a creator and contributor in the digital culture. Previous discussions have focused mostly on playing games and learning. Here, we discuss game making approaches and their benefits for illuminating game preferences and learning both software design and other academic content. We report on an ongoing ethnographic study that documents youth producing video games in a community design studio. We illustrate how video game making can provide a context for addressing issues of participation, transparency and ethics. Author Keywords

The purpose of this study was to assess the precision at the implant interface of titanium, zirconia, and alumina Procera abutments with a hexagonal connection for single-tooth restorations. Twenty Procera abutments were produced with commercially pure titanium, 20 with zirconia, and 20 with alumina using computer-assisted design and manufacture (CAD/CAM). The rotational freedom of the abutments was assessed to detect the precision of fit of each abutment on the top of the implant hexagon. Significant differences relative to rotational freedom were found between groups: the titanium group and the zirconia group did not differ significantly, but both demonstrated significantly smaller mean rotational freedoms than the alumina group (P < .05). Rotational freedom was less than 3 degrees for all abutments. The hexagonal misfit of the Procera abutment on the implant hexagon may be implicated in screw joint loosening. In the present study, all types of CAD/CAM Procera abutments consist...

The proliferation of online simulation games across the globe in many different languages offers Computer Assisted Language Learning (CALL) researchers an opportunity to examine how language learning occurs in such virtual environments. While there has recently been an increase in the number of exploratory studies involving learning experiences of predominantly English as a Second or Foreign Language (ESL/EFL) participants in these environments, the context of a Japanese as a Foreign Language (JFL) classrooms has rarely been examined. To address this, this study investigates a Second Language Acquisition-theory driven instantiation of CALL within the context of a JFL classroom.  Through a mixed-method case study approach, participants’ natural acquisition of Japanese in a 3D virtual environment was examined. Data detailing participants’ communicative capacities in several modalities were collected, as were their attitudes toward participation in a massively multiplayer online (MMO)-based virtual world of Tokyo.

In the present study, eight sources of data from eleven university-level JFL students (n=11) were collected and analyzed to evaluate the learning outcomes from an integrative CALL framework (Warschauer, 2004; Yamazaki, 2014).  Based on both interpretative and statistical analyses of data, the major finding of the present study was that the participants, when immersed in the 3D virtual world of Tokyo, acquired contextualized communicative competence. More specifically, quantitative analyses revealed statistically significant improvement in the participants’ acquisition of incidentally encountered vocabulary, in particular, kanji pronunciation and vocabulary interpretation. Qualitative analyses revealed participants’ acquisition of various communicative competencies specific to the context, including persuasive talk, concept of audience, collaborative communication, and colloquial expressions. Data from a post-hoc reflection survey provided strong evidence that most students found the course to be effective, as it made them use Japanese more than in a regular class, and thereby developed more necessary communicative skills to function in Japan.

Two experiences based on the use of computer tools for teaching courses about the design and analysis of plastic pieces and molds are presented. The purpose is to offer students the opportunity to handle softwares by combining knowledge about plastics, metals, processing, mechanizing, marketing, stresses, costs, and design.ß2005 Wiley Periodicals, Inc. Comput Appl Eng Educ 13: 233À239, 2005; Published online in Wiley InterScience (www.interscience.wiley. com);

The study investigated Effects of Computer Assisted Instruction on Independent Learning Skills of Economics Students in Secondary Schools in Kaduna State. ICT are information handling tools used for producing, processing, distributing exchanging and storing of information. Computer Assisted Instruction (CAI) is an ICT-Driven Instructional technique in which computer system is used as an instructional material and the teacher monitors, the learning that takes place. The objective of the study among others was to determine the rate at which independent learning skills acquisition could be enhanced among Economics students taught with the use of Computer Assisted Instruction and those taught with the conventional method of teaching. Hypotheses were drawn from the objectives of the study. The research design was the two by two pre-test post-test quasi experimental control group design. The targeted population were the twenty-three thousand four hundred and sixty Public Senior Secondary two (SS2) students in twelve educational zones of Kaduna State. A stratified random sampling technique was adopted to draw two hundred SS2 Economics students from the rural and urban centres of two educational zones of the State. An Economics Achievement Test (EAT) was developed and validated as test instrument for data collection. The hypothesis was tested using covariance at 0.05 level of significance for acceptance or rejection. The results amongst others revealed that students taught with the use of CAI performed significantly better than those taught without CAI, and also the result shows that the use of CAI in teaching Economics is not significantly affected by school location. However, it was therefore recommended amongst others that, the Opon Imo meaning Tablet of Knowledge used in Osun State Senior Secondary Schools should be adopted by government for all Senior Secondary Schools in Nigeria.

subjects in the curriculum as well as students’ utilization of and access to ICT, in order to establish a fact on its
implications to e-learning. Data were collected from 105 Form 2 Junior Secondary School students from four Federal
Unity Schools (FUS) in South Eastern Nigeria. Questionnaire was used for data collection that were analysed
descriptively and quantitatively using frequency, percentages, charts, and cross tabulation chi-square to test the null
hypotheses. Findings indicate that except for computer studies, ICT was not integrated into other school subjects in the
curriculum. Although ICT is seldom used, the level of ICT integration into the curriculum χ2 (8, n=105) =7.704 p> .05 has
no significant influence on the level of ICT utilization. Alternatively, students’ access to ICT package, χ2 (12, n=105)
=22.207 p< .05 has a significant influence on ICT utilization; majority (66%) never had access to ICT usage.
Recommendations were directed towards government assistance in equipping FUS with adequate facilities, teacher
preparation towards ICT usage as well as monitoring and assessment of ICT utilization.

Keywords: Access, Information Communication Technology, Junior Secondary School, Integration, Utilizati

This study investigated the effects of computer assisted instruction packages (CAIP) on performances of senior secondary school students' in visual art in Shagamu. Nigeria. Gender influence on students’ performance was also examined. The sample comprised of 50 students drawn from two secondary schools. Validated researchers’ designed computer assisted instructional package and Visual art Performance test were used as treatment and test instrument. Two hypotheses were tested using Analysis of covariance. Finding indicated no significant differences between the performance of students taught with CAIP and those taught using the conventional method and gender was a factor. The findings recommended that computer assisted instructional packages CAIP should be developed for teaching difficult Visual art topics in Nigerian Senior Secondary schools.

Course descriptions prepared by the lecturers in the beginning of the academic year do not get any feed back from the students enrolled it. These syllabuses are not only used for the future semesters, but also used by the other lecturers without even making any changes. This causes a negative effect on the student education since many of the students come with the different backgrounds and interests for the content of the course. In addition to the changing abilities and capabilities of the students every year, there can be administrative changes in the official curriculum. In our approach, we prepared a detailed dynamic web site together with questionnaire filled in advance, that will be applied to the new students to determine their knowledge level. This will also facilitate the preparatory reviews for the lecturers to create a satisfactory education plan based on the student feedback. In this paper, a software assisted questionnaire form through a dynamically updated web page is presented for Computer Networks course. Assessing current level of the students helps to analyze and improve results in many aspects and converges the objectives of the students and the course teacher.

Low retention rates in third-level computing courses, despite continuing research into new and improved computer teaching methods, present a worrying concern. For some computing students learning programming is intimidating, giving rise to lack of confidence and anxiety. The noncognitive domain of anxiety with regard to learning computer programming is investigated in this paper and programming anxiety, a constituent component of computer anxiety, is defined. The paper describes a longitudinal research study that has been conducted, which investigates the variance of anxiety amongst undergraduate computing students, with specific emphasis upon their learning programming during their first year in higher education.

This paper investigates the interactions between design students' cognitive styles, as measured by Riding's Cognitive Styles Analysis, and performance in 2D drafting and design tasks in digital media. An empirical research revealed that Imager students outperformed Verbalisers in both drafting and creativity scores. Wholist-Analytic cognitive style dimension was found to be independent from drafting and design performance. The study suggests that examining the cognitive styles of students in Computer Aided Design (CAD) education deserves further attention and may facilitate for improvements in learning processes.

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Project-based learning (PBL) is a well-known student-centred methodology for engineering design education. The methodology claims to offer a number of educational benefits. This paper evaluates the student perceptions of the initial and second offering of a first-year design unit at Griffith University in Australia. It builds on an earlier evaluation conducted after the initial offering of the unit. It considers the implementation of the recommended changes. Evaluations of the two offerings reveal that students (in both the initial and second offering) generally enjoyed the experience, but that the second offering was found to be a significantly more enjoyable learning experience. Students in the second offering also reported a significantly better understanding of what they needed to do for the design projects and where to find the requisite information. The oral presentation aspect of the initial and second offerings received the lowest satisfaction rating. The inclusion (and delivery) of the computer-aided drawing component of the unit is seen as a positive aspect by some students, but many others comment on it negatively. The best aspects of the PBL unit and those aspects needing further improvement were similar to the findings of other investigations documented in the literature.

Current e-learning forms are commonly based on improving the learning process through the enhancement of certain skills in students, such as collaborative, competitive or problem-based learning. However, it seems that there is still no e-learning formula that gathers the implementation of a number of more generic educational principles in a single e-learning system or platform. Therefore, this paper presents a web-based framework for the creation, development and implementation of heterogeneous learning environments called CADI. It offers a graphical user interface for students to interact with only the need for any generic WiFi compliant device. Its innovative design allows the instructor to select and combine the developed resources to create varied activities, providing content adapted to every single device. The usefulness of the system was tested by introducing a case study to a group of senior college students. The experience showed that the use of the system helped students to achieve better results in their evaluation. It also showed that the students had no problems interacting with it from the outset, promoting their active learning. Design, implementation and assessment results of the system are also presented and analyzed.

It is believed that the bitter taste of paracetamol, a pain killer drug, is due to its hydroxyl group. Hence, it is expected that blocking the hydroxy group with a suitable linker could inhibit the interaction of paracetamol with its bitter taste receptor/s and hence masking its bitterness. Using DFT theoretical calculations we calculated proton transfers in ten different Kirby's enzyme models, 1-10. The calculation results revealed that the reaction rate is linearly correlated with the distance between the two reactive centers (r GM ) and the angle of the hydrogen bonding (α) formed along the reaction pathway. Based on these results three novel tasteless paracetamol prodrugs were designed and the thermodynamic and kinetic parameters for their proton transfers were calculated. Based on the experimental t 1/2 (the time needed for the conversion of 50% of the reactants to products) and EM (effective molarity) values for processes 1-10 we have calculated the t 1/2 values for the conversion of the three prodrugs to the parental drug, paracetamol. The calculated t 1/2 values for ProD 1-3 were found to be 21.3 hours, 4.7 hours and 8 minutes, respectively. Thus, the rate by which the paracetamol prodrug undergoes cleavage to release paracetamol can be determined according to the nature of the linker of the prodrug (Kirby's enzyme model 1-10). Further, blocking the phenolic hydroxyl group by a linker moiety is believed to hinder the paracetamol bitterness.

This paper presents two studies in which an empirical approach was taken to understand and explain form generation and decisions taken in the design process. In particular, the activities addressing aesthetic aspects when exteriorising form ideas in the design process have been the focus of the present study. Diary methods were the starting point of this research for investigating the form generation process through collecting self-reflective comments from the participants. The main focus of this paper is to address potentials and limitations of the three variants of diary method used for data collection, namely, unstructured diaries, structured diaries and visual diaries. A set of method evaluation criteria was developed to compare the structure of the diary variants. By qualitative analysis of the results and comparison of the diary variants, strengths and weaknesses of each variant were identified. One of the prominent factors in the diary variants was pegged to be due to the logging delay after the occurrence of the activities.

explained spatial intelligence as one of the basic human intelligences, "the ability to perceive the visual-spatial world accurately and to perform transformations on those perceptions" (as cited in Lieu & Sorby, 2009, p. 3-2). More specifically, spatial visualization is the ability "to imagine the rotation of a depicted object, the folding and unfolding of flat patterns, and the relative changes of positions of objects in space" (Miller & Bertoline, 1991, p. 9). According to Thurstone (1938), this spatial ability is a critical component of intellectual ability. Furthermore, Thurstone (1950) identified seven factors related to human intelligence with three specifically referring to visual orientation in space: • S 1 : "The ability to recognize the identity of an object when it is seen from different angles" (p. 518). • S 2 : "The ability to imagine the movement or internal displacement among the parts of a configuration" (p. 518). • S 3 : "The ability to think about those spatial relations in which the body orientation of the observer is an essential part of the problem" (p. 519). Spatial vision (or developed spatial reasoning) is known "as the most [fundamental and] rewarding part of engineering graphics instruction" (Contero, Naya, Company, & Saorín, 2006, p. 472). Improving students' spatial skills is considered to be an important component in technical education, which is typically found in the first-year Technology Education and Industrial Technology curriculum. It is critical that students develop spatial skills early in engineering curriculum in order to ensure success throughout their program and, thus, promote retention (Sorby, 2009). For this study, the following was the primary research question: Is there a difference in spatial visualization ability, as measured through technical drawings, among the impacts of model types (2D drawing, 3D computer generated drawing, and 3D printed object)?

This paper discusses the use at the University of Windsor (Ontario) of a small World Wide Web-based tool for course delivery and administration called HAL (HTML-based Administrative Lackey), written in the Scheme programming language. This tool was developed by the author to provide Web-based services for a large first-year undergraduate course in computer-aided design. Various problems encountered in administering the course are discussed, and a solution is proposed that includes formation of student design groups, maintaining registration information, facilitating communications, disseminating information, and assigning and recording grades. The design and implementation of HAL is then briefly described, and examples are given. Based on the success of HAL, it is concluded that-although larger and more complex course delivery systems are suitable in some circumstances-there are situations in which simpler and smaller systems are better suited. Three figures present plain scheme code for an HTML (HyperText Markup Language) unordered list, an HTML unordered list using the Scheme CGI (Common Gateway Interface) library, and construction of a whole HTML page using the Scheme CGI library. (Author/AEF) *

This paper presents the results of a study that was conducted to identify and document student perceptions of the effectiveness of computer modeling software introduced in a design foundations course that had previously utilized only conventional manually-produced representation techniques. Rather than attempt to utilize a production-oriented CAD program, this exploratory study investigated the use of alter native software applications developed by vendors specifically to function as conceptual design tools. The study was structured to identify areas of future investigation related to student perceptions of the effectiveness of the software in facilitating design exploration, the effectiveness and ease of use of various application features, and the extent to which prior CAD coursework was related to the perceived effectiveness of the software on design outcomes.

Nana Osei Bonsu (Mr.), Brandford Bervell (Ph.D.), Emelia Kpodo (Ms.), Valentina Arkorful (Ph.D.), John K. E. Edumadze (Mr.), Aburaman Senior High School, Ghana, College of Distance Education, University of Cape Coast, Ghana, Independent Researcher, Ghana, E-learning and Technology Unit, College of Distance Education, University of Cape Coast, Cape Coast, Ghana. Deputy Director, Directorate of ICT&#39;s, University of Cape Coast, Cape Coast, Ghana. Email: nanseezy@gmail.com, b.bervell@ucc.edu.gh, kpodo.mily@gmail.com, valentina.arkorful@ucc.edu.gh, jedumadze@ucc.edu.gh

Our focus is on the design of systems (pedagogical, technical, social) that encourage mathematical abstraction, a process we refer to as designing for abstraction. In this paper, we draw on detailed design experiments from our research on children's understanding about chance and distribution to represent this work as a case study in designing for abstraction. Through the case study, we elaborate a number of design heuristics that we claim are also identifiable in the broader literature on designing for mathematical abstraction. Our previous work on the micro-evolution of mathematical knowledge indicated that new mathematical abstractions are routinely forged in activity with available tools and representations, coordinated with relatively naïve unstructured knowledge. In this paper, we identify the role of design in steering the micro-evolution of knowledge towards the focus of the designer's aspirations. A significant finding from the current analysis is the identification of a heuristic in designing for abstraction that requires the intentional blurring of the key mathematical concepts with the tools whose use might foster the construction of that abstraction. It is commonly recognized that meaningful design constructs emerge from careful analysis of children's activity in relation to the designer's own framework for mathematical abstraction. The case study in this paper emphasizes the insufficiency of such a model for the relationship between epistemology and design. In fact, the case study characterises the dialectic relationship between epistemological analysis and design, in which the theoretical foundations of designing for abstraction and for the micro-evolution of mathematical knowledge can co-emerge.

This work discusses the numerical and physical models developed for the design of a membrane roof for the Baptist Church of Fortaleza, as well as the fabrication and construction of the actual membrane, comparing results of the models with those of the real structure. The roof area amounts to about 2900m 2 , a national record for flexible border membranes and, to the authors knowledge, the first case of a fully computer-assisted design process within Brazil. The paper initially outlines procedures to form finding, stress analysis and patterning, and then focus on the physical models developed to validate them. Finally, construction of the actual membrane is described, and comparison is made with the previous numerical and physical models. Determination of the mechanical properties of the fabrics used to construct the membrane are also be briefly discussed.

In this paper we present the results of research work, that forms part of the activities of the EUfunded project SLOOP: Sharing Learning Objects in an Open Perspective, aimed at encouraging the definition, development and management of Open Educational Resources based on the Learning Object paradigm . We present a model of Open Learning Object (OpenLO) for a greater awareness in the use of LOs by teachers, giving them a more active role in the evolution of educational resources; the OpenLO model extends the concept of reusability, providing pedagogical sustainability. Moreover, we compare FreeLOms, a Learning Object Management System that implements the proposed OpenLO model, to traditional tools for handling LOs.

Density Functional Theory (DFT) and ab initio calculation results for the proton transfer reaction in Kirby's enzyme models 1-6 reveal that the reaction rate is largely dependent on the existence of a hydrogen bonding net in the reactants and the corresponding transition states. Further, the distance between the two reacting centers and the angle of the hydrogen bonding formed along the reaction path has profound effects on the rate. Hence, the study on the systems reported herein could provide a good basis for designing antimalarial (atovaquone) pro-drug systems that can be used to release the parent drug in a controlled manner. For example, based on the calculated log EM, the cleavage process for pro-drug 1Pro may be predicted to be about 10 11 times faster than that for a pro-drug 4Pro and about 10 4 times faster than pro-drug 2Pro: rate 1Pro > rate 2Pro > rate 4Pro . Thus, the rate by which the pro-drug releases the antimalarial drug can be determined according to the nature of the linker (Kirby's enzyme model 1-6).

Computer-based assessment of exams provides teachers and students with two main benefits: fairness and effectiveness in the evaluation process. This paper proposes a fully automatic evaluation tool for the Graphic and Virtual Design (GVD) curriculum at the First School of Architecture of the Politecnico di Torino, Italy. In particular, the tool is designed for the 3D modeling course, taught during the second year, where students have to prove their ability to model static scenes using the open source modeler Blender. During the final exam, students are required to create a 3D model as similar as possible to a reference object proposed by the teacher and shown through a set of 2D views; the similarity of the images is judged according to both model shape and materials. The traditional assessment process is particularly slow and strongly based on teachers subjective evaluation; the proposed solution efficiently implements an objective assessment mechanism that exploits computer vision and image analysis algorithms to automatically extract similarity indices. These indices are related to partial evaluation grades, which are then combined to obtain the final mark. A comparison with the traditional assessment process shows robustness and trustworthiness of the designed approach.

More than a decade has passed since the introduction of computer-assisted instruction (CAI) within schools in Africa. Computer-assisted instruction has enhanced teaching and learning at all levels of education in Africa. However, many aspects of the issues facing CAI implementation, as well as its effects on students' performance in the history classroom are unclear. This necessitated the systematic review into two aspects. Firstly, the effects of CAI on students' performance in the teaching and learning of history in Africa, and secondly, the various challenges facing CAI's implementation in Africa. Furthermore, to facilitate future research, the researchers summarised several research methodologies used in the studies reviewed. The results from a systematic review of 11 studies revealed that CAI has a positive effect on students' academic performance in history. The challenges to CAI implementation that were identified included: a lack of funding, training of teachers, and of motivation on the part of teachers; inadequate technological infrastructure; a lack of Internet; an unstable power supply; a lack of technological support; the poor information communication technology (ICT) skills of history and social studies teachers; a lack of school-based policies; and a digital divide between male and female students. Moreover, a quantitative approach was the preferred design with both descriptive and inferential statistics as the main statistical tools used for the data analysis. Additionally, there is a scarcity in research studies that employ an experimental design to test for the effect of CAI upon academic performance in history teaching. Lastly, the studies that use a questionnaire tool for data analysis can take a progressive step further by conducting structural equation modelling, which is an advanced quantitative analysis.

The aircraft industry has a conception cycle based on a massive use of Computer Assisted Design in order to allow more complex plane designs, and cheaper development costs compared to multiple prototyping steps. Among the many processes necessary to validate calculated aerodynamic models, real time pressure measurements are made on the wings during test flights. Such measurements are currently performed using wired sensors, with all the cost and weight problems it causes. Advances in wireless sensor network performances and improvement of attainable bit rates allow research on such measurement systems using Wireless Sensor Networks (WSNs). However, current WSN synchronization protocols do not reach performances required for a reliable correlation of data collected by all the sensors. In this paper, we present a solution to overcome this difficulty to reach sub-microsecond synchronization based on cross-layered design. Specific algorithms are implanted into the MAC and physical layers and form a cross-layered synchronization protocol for deterministic Wireless Sensor Networks named WiDeCS (Wireless Deterministic Clock Synchronization). This protocol propagates master time reference to nodes of a cluster tree network. WiDeCS Cross layered scheme is possible thanks to flag signals in the physical layer. These signals capture precise dates of transmission and reception. Hardware level simulations show a synchronization precision of 100 ns. In this paper, the sources of variable delays in WSN network interfaces are detailed, and the effect of cross-layered WiDeCS scheme on the knowledge of different delays is explained.

This paper presents two studies in which an empirical approach was taken to understand and explain form generation and decisions taken in the design process. In particular, the activities addressing aesthetic aspects when exteriorising form ideas in the design process have been the focus of the present study. Diary methods were the starting point of this research for investigating the form generation process through collecting self-reflective comments from the participants. The main focus of this paper is to address potentials and limitations of the three variants of diary method used for data collection, namely, unstructured diaries, structured diaries and visual diaries. A set of method evaluation criteria was developed to compare the structure of the diary variants. By qualitative analysis of the results and comparison of the diary variants, strengths and weaknesses of each variant were identified. One of the prominent factors in the diary variants was pegged to be due to the log...

Two porous titanium implants with a pore size diameter of 800 and 1200 lm (Ti800 and Ti1200) and an interconnected network were manufactured using rapid prototyping. Their dimensions and structure matched those of the computer assisted design. The porosity of the implants was around 60%. Their compressive strength and Young's modulus were around 80 MPa and 2.7 GPa, respectively. These values are comparable to those of cortical bone. The implants were implanted bilaterally in the femoral epiphysis of 15 New Zealand White rabbits. After 3 and 8 weeks, abundant bone formation was found inside the rapid prototyped porous titanium implants. For the Ti1200 implants, bone ingrowth was (23.9 6 3.5)% and (10.3 6 2.8)%, respectively. A significant statistical differ-ence (p < 0.05) was found for bone ingrowth in the Ti1200 between the two delays. The percentage of bone directly apposited on titanium was (35.8 6 5.4)% and (30.5 6 5.0)%. No significant difference was found for boneimplant contact between the different time periods and pore sizes. This work demonstrates that manufacturing macroporous titanium implants with controlled shape and porosity using a rapid prototyping method is possible and that this technique is a good candidate for orthopedic and maxillofacial applications.

BACKGROUND AND PURPOSE: How CSF flow varies with the anatomy of the subarachnoid space has not been sufficiently well studied. The goal of this study was to develop an idealized 3D computational model of the subarachnoid space and then to use this model to study the detailed spatiotemporal effects of anatomic variations on CSF pressures and velocities. MATERIALS AND METHODS:

The aim of this study was to evaluate and compare the biocompatibility of computer-assisted designed (CAD) synthetic hydroxyapatite (HA) and tricalciumphosphate (TCP) blocks and natural bovine hydroxyapatite blocks for augmentations and endocultivation by supporting and promoting the proliferation of human periosteal cells. Human periosteum cells were cultured using an osteogenic medium consisting of Dulbecco's modified Eagle medium supplemented with fetal calf serum, Penicillin, Streptomycin and ascorbic acid at 37°C with 5% CO 2 . Three scaffolds were tested: 3D-printed HA, 3D-printed TCP and bovine HA. Cell vitality was assessed by Fluorescein Diacetate (FDA) and Propidium Iodide (PI) staining, biocompatibility with LDH, MTT, WST and BrdU tests, and scanning electron microscopy. Data were analyzed with ANOVAs. Results: After 24 h all samples showed viable periosteal cells, mixed with some dead cells for the bovine HA group and very few dead cells for the printed HA and TCP groups. The biocompatibility tests revealed that proliferation on all scaffolds after treatment with eluate was sometimes even higher than controls. Scanning electron microscopy showed that periosteal cells formed layers covering the surfaces of all scaffolds 7 days after seeding. Conclusion: It can be concluded from our data that the tested materials are biocompatible for periosteal cells and thus can be used as scaffolds to augment bone using tissue engineering methods.

This report details improvements made on a code used for computer assisted design (CAD) of scalable spin-qubit circuits based on multiple quantum dots. It provides a brief scientiflc framework as well as an overview of the physical and numerical model. Then modiflcations and improvements to the code based on utilization of PETSc are listed. Then new and old codes are benchmarked on three NCSA computer clusters. The speed-up of the code is considerable: about 10 times for the eigenvalue solver and 2 times for the Poisson equation solver. An example of code application towards quantum dot modeling is also given. Finally, conclusions and recommendations for future work are provided.

This report describes a theoretical study of the 1,3-dipolar cycloadditions between dimethylvinylborane and different chiral nitrones, aimed at identifying the requisite structural features to achieve high levels of selectivity. Excellent regioselectivities towards the formation of the 5-borylisoxazolidines are computed in all cases due to the presence of a strong secondary orbital interaction between the boron of the vinylborane and the oxygen of the nitrones. While these transition structures show [3C3] character, 4-boryl regioisomeric structures have classical [3C2] character with weak carbon-boron secondary orbital interactions. Endo transition structures leading to the favoured products adopt chair-like conformations only, unlike their exo counterparts, which exhibit either boat or twist-boat structures. Placing a stereocentre adjacent to the nitrone nitrogen appears to be an effective strategy to stereodiscriminate the anti and syn approaches of the dipolarophile.

Two porous titanium implants with a pore size diameter of 800 and 1200 lm (Ti800 and Ti1200) and an interconnected network were manufactured using rapid prototyping. Their dimensions and structure matched those of the computer assisted design. The porosity of the implants was around 60%. Their compressive strength and Young's modulus were around 80 MPa and 2.7 GPa, respectively. These values are comparable to those of cortical bone. The implants were implanted bilaterally in the femoral epiphysis of 15 New Zealand White rabbits. After 3 and 8 weeks, abundant bone formation was found inside the rapid prototyped porous titanium implants. For the Ti1200 implants, bone ingrowth was (23.9 6 3.5)% and (10.3 6 2.8)%, respectively. A significant statistical difference (p < 0.05) was found for bone ingrowth in the Ti1200 between the two delays. The percentage of bone directly apposited on titanium was (35.8 6 5.4)% and (30.5 6 5.0)%. No significant difference was found for boneimplant contact between the different time periods and pore sizes. This work demonstrates that manufacturing macroporous titanium implants with controlled shape and porosity using a rapid prototyping method is possible and that this technique is a good candidate for orthopedic and maxillofacial applications.

A computer assisted molecular modeling was used to design molecules having a shape complementary to the active site of glutathione reductase (GR) and trypanothione reductase (TR). The designed 5-nitro compound derivatives, were obtained from structural knowledge gleaned on glutathione (GSSG), trypanothione (T[S] 2 ) and GSP disul®de (glutathionylspermidine disul-®de). These molecules form complexes with the enzymes GR and TR. The theoretical lead compound was: N1-[1-(5-nitro-2furyl)methylidene]-N4-{4-[3-(2,2,2-tri¯uoroacetyl)hexahydro-1-1-pyrimidynil]butyl} semicarbazide (NPIPCO). A multidisciplinary team developed around the efforts to synthesize this lead. In this work we report on eight compounds that were synthesized in the pathway to NPIPCO: 4-(2-methoxyethyl)-1-, 4-butyl-1-, 4-hexyl-1-and 2-methoxphenyl-1-(5-nitrofurfurilidene) semicarbazides and the corresponding 5-nitrothiophenes. These substances are expected to act as pro-transition state analogues. Enzymologic studies proved that many of these compounds are inhibitors of TR. Furthermore, they showed inhibitory activity on Tripanosoma cruzi growth in vitro. q Journal of Molecular Structure (Theochem) 584 (2002) 95±105 0166-1280/02/$ -see front matter q (O. Tapia).

Two porous titanium implants with a pore size diameter of 800 and 1200 lm (Ti800 and Ti1200) and an interconnected network were manufactured using rapid prototyping. Their dimensions and structure matched those of the computer assisted design. The porosity of the implants was around 60%. Their compressive strength and Young's modulus were around 80 MPa and 2.7 GPa, respectively. These values are comparable to those of cortical bone. The implants were implanted bilaterally in the femoral epiphysis of 15 New Zealand White rabbits. After 3 and 8 weeks, abundant bone formation was found inside the rapid prototyped porous titanium implants. For the Ti1200 implants, bone ingrowth was (23.9 6 3.5)% and (10.3 6 2.8)%, respectively. A significant statistical differ-ence (p < 0.05) was found for bone ingrowth in the Ti1200 between the two delays. The percentage of bone directly apposited on titanium was (35.8 6 5.4)% and (30.5 6 5.0)%. No significant difference was found for boneimplant contact between the different time periods and pore sizes. This work demonstrates that manufacturing macroporous titanium implants with controlled shape and porosity using a rapid prototyping method is possible and that this technique is a good candidate for orthopedic and maxillofacial applications.

A new beta þ radiosensitive microprobe implantable in rodent brain dedicated to in vivo and autonomous measurements of local time activity curves of beta radiotracers in a volume of brain tissue of a few mm 3 has been developed recently. This project expands the concept of the previously designed beta microprobe, which has been validated extensively in neurobiological experiments performed on anesthetized animals. Due to its limitations considering recordings on awake and freely moving animals, we have proposed to develop a wireless setup that can be worn by an animal without constraining its movements. To that aim, we have chosen a highly beta sensitive Silicon-based detector to devise a compact pixellated probe. Miniaturized wireless electronics is used to read-out and transfer the measurement data. Initial Monte-Carlo simulations showed that high resistive Silicon pixels are appropriate for this purpose, with their dimensions to be adapted to our specific signals. More precisely, we demonstrated that 200 mm thick pixels with an area of 200 mm  500 mm are optimized in terms of beta þ sensitivity versus relative transparency to the gamma background. Based on this theoretical study, we now present the development of the novel sensor, including the system simulations with technology computer-assisted design (TCAD) to investigate specific configurations of guard rings and their potential to increase the electrical isolation and stabilization of the pixel, as well as the corresponding physical tests to validate the particular geometries of this new sensor.

The aim of this study was to evaluate the ability of computer assisted designed (CAD) synthetic hydroxyapatite and tricalciumphosphate blocks to serve as precise scaffolds for intramuscular bone induction in a rat model. A central channel to allow for vessel pedicle or nerve integration was added. Natural bovine hydroxyapatite blocks served as controls to evaluate and compare biocompatibility of the new matrices.

Discussion is often reported concerning potential links between computer-aided designing and creativity, but there is a lack of systematic enquiry to gather empirical evidence concerning such links. This paper reports an indication of findings from other research studies carried ...

More than a decade has passed since the introduction of computer-assisted instruction (CAI) within schools in Africa. Computer-assisted instruction has enhanced teaching and learning at all levels of education in Africa. However, many aspects of the issues facing CAI implementation, as well as its effects on students&#39; performance in the history classroom are unclear. This necessitated the systematic review into two aspects. Firstly, the effects of CAI on students&#39; performance in the teaching and learning of history in Africa, and secondly, the various challenges facing CAI&#39;s implementation in Africa. Furthermore, to facilitate future research, the researchers summarised several research methodologies used in the studies reviewed. The results from a systematic review of 11 studies revealed that CAI has a positive effect on students&#39; academic performance in history. The challenges to CAI implementation that were identified included: a lack of funding, training of teach...