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The GGUM2004 computer program estimates parameters for a family of unidimensional unfolding item response theory (IRT) models. These unfolding IRT models predict higher item scores to the extent that a respondent is located close to an item on an underlying latent continuum. This prediction is often consistent with responses to traditional Thurstone or Likert attitude questionnaires. Unfolding IRT models can also be used to measure individual differences in preference and certain developmental processes in which behaviors/cognitions occur in unique stages.The GGUM2004 software estimates parameters of the generalized graded unfolding model (GGUM), developed by Roberts, Donoghue, and Laughlin (2000). In addition, the program can estimate parameters in seven other models that are derived by constraining GGUM item parameters in various ways. GGUM2004 estimates item parameters using a marginal maximum likelihood technique, and person parameters are estimated using an expected a posteriori method. The software can analyze responses to a maximum of 100 items, in which each item has up to 10 graded response categories. The program will allow for a maximum of 2,000 respondents. The GGUM2004 program extends the capabilities of its predecessor (GGUM2000; Roberts, 2001) in many useful ways:• It incorporates a graphical user interface that runs in a Windows environment.• It allows the number of response categories to vary across items. This increases the variety of questionnaires that can be studied and enables users to collapse item categories with sparse response frequencies on an item-by-item basis. • It allows for missing item responses under the assumption that those responses are missing at random. • It calculates new item fit statistics with more desirable statistical properties. It also calculates information criteria relating to model fit. • It provides a wide variety of real-time graphics that describe the performance of the selected model. • It provides faster calculation of model parameter estimates.The GGUM2004 software consists of a core FORTRAN parameter estimation program along with a Visual Basic interface that allows users to execute the core program and view the resulting text and graphics output files. The program has been successfully tested under the Windows 98 SE, Windows 2000 Professional, and Windows XP Professional operating systems using the latest

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This in vivo pilot study explored the use of mesenchymal stem cell (MSC) containing tissue engineering constructs in repair of osteochondral defects. Osteochondral defects were created in the medial condyles of both knees of 16 miniature pigs. One joint received a cell/collagen tissue engineering construct with or without pretreatment with transforming growth factor b (TGF-b) and the other joint from the same pig received no treatment or the gel scaffold only. Six months after surgery, in knees with no treatment, all defects showed contracted craters; in those treated with the gel scaffold alone, six showed a smooth gross surface, one a hypertrophic surface, and one a contracted crater; in those with undifferentiated MSCs, five defects had smooth, fully repaired surfaces or partially repaired surfaces, and one defect poor repair; in those with TGF-b-induced differentiated MSCs, seven defects had smooth, fully repaired surfaces or partially repaired surfaces, and three defects showed poor repair. In Pineda score grading, the group with undifferentiated MSC, but not the group with TGF-b-induced differentiated MSCs, had significantly lower subchondral, cell morphology, and total scores than the groups with no or gel-only treatment. The compressive stiffness was larger in cartilage without surgical treatment than the treated area within each group. In conclusion, this preliminary pilot study suggests that using undifferentiated MSCs might be a better approach than using TGF-b-induced differentiated MSCs for in vivo tissue engineered treatment of osteochondral defects. ß

We present a new non-dominated sorting algorithm to generate the non-dominated fronts in multi-objective optimization with evolutionary algorithms, particularly the NSGA-II. The non-dominated sorting algorithm used by NSGA-II has a time complexity of O(MN2) in generating non-dominated fronts in one generation (iteration) for a population size N and M objective functions. Since generating non-dominated fronts takes the majority of total computational time (excluding the cost of fitness evaluations) of NSGA-II, making this algorithm faster will significantly improve the overall efficiency of NSGA-II and other genetic algorithms using non-dominated sorting. The new non-dominated sorting algorithm proposed in this study reduces the number of redundant comparisons existing in the algorithm of NSGA-II by recording the dominance information among solutions from their first comparisons. By utilizing a new data structure called the dominance tree and the divide-and-conquer mechanism, the new algorithm is faster than NSGA-II for different numbers of objective functions. Although the number of solution comparisons by the proposed algorithm is close to that of NSGA-II when the number of objectives becomes large, the total computational time shows that the proposed algorithm still has better efficiency because of the adoption of the dominance tree structure and the divide-and-conquer mechanism.

In our previous study, we found that cartilage fragments from osteoarthritic knee promoted chondrogenesis of mesenchymal stem cells. In this study, we further transformed the cartilage tissues into acellular cartilage matrix (ACM) and explored the feasibility of using ACM as a biological scaffold. Nonworn parts of cartilage tissues were obtained during total knee arthroplasty (TKA) surgery and were successfully fabricated into ACM powders. The ACM powders and human synovium-derived mesenchymal stem cells (SMSCs) were mixed into collagen gel for in vitro culture. Histological results showed a synergistic effect of ACM powders and chondrogenic growth factors in the formation of engineered cartilage. The findings of real-time polymerase chain reaction (PCR) suggested that ACM powders had the potential of promoting type II collagen gene expression in the growth factors-absent environment. Moreover, with growth factors induction, the ACM powders could reduce the hypertrophy in chondrogenesis of SMSCs. In summary, ACM powders could serve as a functional scaffold that benefited the chondrogenesis of SMSCs for cartilage tissue engineering.