Development and Validation of a Descriptive Cognitive Model for Predicting Usability Issues in a Low-Code Development Platform.

OBJECTIVE: The aim of the study was the development and evaluation of a Descriptive Cognitive Model (DCM) for the identification of three types of usability issues in a low-code development platform (LCDP). BACKGROUND: LCDPs raise the level of abstraction of software development by freeing end-users from implementation details. An effective LCDP requires an understanding of how its users conceptualize programming. It is necessary to identify the gap between the LCDP end-users' conceptualization of programming and the actions required by the platform. It is also relevant to evaluate how the conceptualization of the programming tasks varies according to the end-users' skills. METHOD: DCMs are widely used in the description and analysis of the interaction between users and systems. We propose a DCM which we called PRECOG that combines task decomposition methods with knowledge-based descriptions and criticality analysis. This DCM was validated using empirical techniques to provide the best insight regarding the users' interaction performance. Twenty programmers (10 experts, 10 novices) were observed using an LCDP and their interactions were analyzed according to our DCM. RESULTS: The DCM correctly identified several problems felt by first-time platform users. The patterns of issues observed were qualitatively different between groups. Experts mainly faced interaction-related problems, while novices faced problems attributable to a lack of programming skills. CONCLUSION: By applying the proposed DCM we were able to predict three types of interaction problems felt by first-time users of the LCDP. APPLICATION: The method is applicable when it is relevant to identify possible interaction problems, resulting from the users' background knowledge being insufficient to guarantee a successful completion of the task at hand.

Infiltrating syringomatous adenoma of the nipple.

Infiltrating syringomatous adenoma of the nipple is a rare, benign, locally invasive tumor with recurrence potential, showing sweat duct differentiation. It can clinically, radiologically and pathologically mimic cancer. Histopathologically, it must be distinguished from florid papillomatosis, adenosquamous carcinoma, adenoid cystic carcinoma and sclerosing syringomatous carcinoma. A 44-year-old woman presented with pain on the right nipple for 7 days. On physical exam there was an irregular nodule on nipple area with edema. The skin was intact. The ultrasound showed a hypoechoic irregular nodule measuring 7.5 mm in the nipple area. The mammography was unspecific. The lesion was surgically removed and histopathologically, the tumor was composed of ducts and tubules lined with a double-layered epithelial cells. The lining cells were small, cuboidal with a central nuclei and eosinophilic nuclei. The stroma was dense with lymphocytes and plasma cells, and compressed many of the ducts that contained a comma or tadpole-shape, giving an impression of a syringoma. Some ducts were slightly dilated with squamous metaplasia. Some of these cysts were connected with the overlying epidermis. Mitotic figures were rare and no pleomorfism or hyperchromasia was observed. At the periphery, the ducts invaded muscular fibers of the nipple. The surgical margins were free of neoplastic involvement. Patient has no signs of progression of disease in 1 year of follow-up.

Evaluation of occlusal rest seats with 3D technology in dental education.

The preparation of rest seats must comply with specific sizes and shapes. Various technological systems such as Kavo PrepAssistant have been used as an auxiliary method to evaluate preclinical preparations more objectively. The aims of this study were to establish an alternative system for evaluating occlusal rest seats and to compare different types of assessment. Seventy-six undergraduate students at Oporto University Faculty of Dental Medicine in Portugal were selected as a convenience sample to prepare two occlusal rest seats in Kavo teeth #45 and #46 (FDI World Dental Federation ISO-3950) and were randomly assigned to two groups. Bearing in mind the ideal characteristics of rest seats, the investigators defined ten assessment parameters, and their evaluation weights were independently estimated by three evaluators. Four of these parameters were measured in Kavo PrepAssistant. The results of the different evaluation methods and evaluators varied considerably. The classical evaluation presented final results worse than those of the evaluations using parameters. In this study, carrying out the assessment with Kavo PrepAssistant helped to achieve a more objective and less evaluator-dependent final evaluation.

Finite element analysis of the mechanical behavior of a partially edentulous mandible as a function of cancellous bone density / Análise por elementos finitos do comportamento mecânico de uma mandíbula humana parcialmente edêntula em função da densidade óssea trabecular

Purpose: To present a methodological procedure to obtain the geometric and discrete models of a human mandible for numerical simulation of the biomechanical behavior of a partially edentulous mandible as a function of cancellous bone density. Methods: A 3D finite element method was used to assess the model of a partially edentulous mandible, Kennedy Class I, with dental implants placed at the region of teeth 33 and 43. The geometric solid model was built from CT-scan images and prototyping. In the discrete model a parametric analysis was performed to analyze the influence of cancellous bone density (25 %, 50 %, 75 %) on the development of mandibular stress and strain during simulation of masticatory forces in the anterior region. Results: Maximum von Mises stress and equivalent strain values in cancellous bone were found close to the loading area (masticatory forces). The peak stress and strain values occurred in the mandibular anterior region, and for the same masticatory force the equivalent stresses increased with bone density. Conclusion: The results suggest that the stresses and strains developed in the mandibular model were affected by cancellous bone density during the simulation of masticatory activity.

Objetivo: Apresentar uma metodologia para modelamento geométrico de uma mandíbula humana e obtenção de um modelo discreto para simular numericamente o comportamento biomecânico de uma mandíbula parcialmente edêntula em função de diferentes densidades do osso trabecular. Metodologia: Utilizou-se o método de elementos finitos 3D para realizar um estudo numérico sobre um modelo de mandíbula humana, desdentada parcial tipo Classe I de Kennedy, com implantes nas regiões dos dentes 33 e 43. O modelo sólido geométrico foi determinado por tomografia computorizada e prototipagem. No modelo discretizado foi realizada uma análise paramétrica para verificar a influência da densidade óssea do osso trabecular (25 %, 50 %, 75 %) no desenvolvimento de tensões e deformações da mandíbula durante a aplicação de forças mastigatórias na região anterior. Resultados: As tensões máximas de von Mises e deformações equivalentes no osso trabecular foram desenvolvidas próximo às regiões de aplicação das forças de mordida. Os picos de valores de tensões/deformações localizaram-se na região anterior da mandíbula, sendo que, para o mesmo valor de esforço de mordida, as tensões equivalentes aumentaram com a densidade óssea. Conclusão: Os resultados sugerem que as tensões e deformações desenvolvidas no modelo mandibular testado foram afetadas pelo grau de densidade do osso trabecular durante simulação de atividade mastigatória.