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关键词： Graphics   Software engineering   Companies   Three-dimensional displays   Solid modeling   Government   Computational modeling   Layout   Hardware   Design automation   CADCAM   Research and development   History   Product design   Product development  

摘要： This article tells the history of CAD research and commercial activities in Cambridge, U.K., from the early 1960s to the late 1980s. As well as a brief overview of the early research at Cambridge University, this article describes the government intervention that led to the creation of the Computer-Aided Design Centre (CADCentre) R&D establishment. It also explains how the university and the CADCentre became a center of excellence and the focus for U.K. CAD developments. It tells the stories behind numerous commercial software products that emerged from the CADCentre and the people and companies that developed them.

关键词： extracellular vesicles   multiple sclerosis disease   cerebrospinal fluid-derived EVs   serum-derived EVs   tetraspanins   GLAST   L1CAM   central nervous system-derived EVs   neural-derived EVs   brain-derived EVs  

摘要： Objective: This study aimed to unravel the single tetraspanin pattern of extracellular vesicles (EVs), L1CAM+ and GLAST+ EV levels as diagnostic biomarkers to stratify people with multiple sclerosis (pwMS), specifically relapsing-remitting (RRMS) and primary progressive (PPMS). Methods: The ExoView platform was used to directly track single EVs using a clinically feasible volume of cerebrospinal fluid (CSF) and serum samples. This technology allowed us to examine the patterns of classical tetraspanin and quantify the levels of L1CAM and GLAST proteins, commonly used to immunoisolate putative neuron- and astrocyte-derived EVs. Results: The tetraspanin EV pattern does not allow us to differentiate RRMS, PPMS and non-MS donors neither in CSF nor serum, but this was associated with the type of biofluid. L1CAM+ and GLAST+ EVs showed a very low presence of tetraspanin proteins. Additionally, a significant decrease in the particle count of L1CAM+ EVs was detected in L1CAM-captured spots, and L1CAM+ and GLAST+ EVs decreased in GLAST-captured spots in the CSF from PPMS subjects compared to RRMS. Interestingly, only GLAST+ EVs exhibited a lower quantity in the CSF from PPMS compared to both MS and non-MS samples. Finally, GLAST+ EVs demonstrated a medium negative and significative correlation with GFAP levels-a biomarker of MS progression, astrocyte damage and neurodegenerative processes. Conclusions: ExoView technology could track neural EV biomarkers and be potentially useful in the diagnostic evaluation and follow-up of pwMS. GLAST+ EVs might provide insights into the etiology of PPMS and could offer small windows to elucidate the molecular mechanisms behind its clinical presentation.

关键词： Incidental Pulmonary Nodule   Early Detection   Artificial Intelligence  

关键词： Symbolic computation   Machine learning   Data augmentation   Classification   Regression   Cylindrical algebraic decomposition  

摘要： Symbolic Computation algorithms and their implementation in computer algebra systems often contain choices which do not affect the correctness of the output but can significantly impact the resources required: such choices can benefit from having them made separately for each problem via a machine learning model. This study reports lessons on such use of machine learning in symbolic computation, in particular on the importance of analysing datasets prior to machine learning and on the different machine learning paradigms that may be utilised. We present results for a particular case study, the selection of variable ordering for cylindrical algebraic decomposition, but expect that the lessons learned are applicable to other decisions in symbolic computation. We utilise an existing dataset of examples derived from applications which was found to be imbalanced with respect to the variable ordering decision. We introduce an augmentation technique for polynomial systems problems that allows us to balance and further augment the dataset, improving the machine learning results by 28% and 38% on average, respectively. We then demonstrate how the existing machine learning methodology used for the problem-classification-might be recast into the regression paradigm. While this does not have a radical change on the performance, it does widen the scope in which the methodology can be applied to make choices.

关键词： Hand   ergonomics   anthropometrics   X-ray   average hand model   CAD  

摘要： To design a comfortable hand support, the population-specific morphological characteristics of human hands must be known. Surface and bone anthropometric data from 177 radiograms of the left hands of an unselected sample of 87 subjects (training set) belonging to the Italian, female population (age 58 +/- 12) were collected. Hand Length (HL) and Hand Width (HW) were respectively 172 +/- 8 mm and 81 +/- 4 mm;Hand Bone Length (HBL) was 179 +/- 8 mm. A separate validation set consisting of 25 radiograms from 25 patients belonging to the same population was also collected. Bone and surface measurements were compared to validate the relationships proposed by Kong et al. Their approach applied to the validation set resulted in errors between 3.1% and 8.7%, which is almost as accurate (low bias) but somewhat less precise (higher mean errors) than what found by Kong et al. on their own sample belonging to the Korean population. Two methods were developed to predict the positions of the Metacarpo-phalangeal joints of the Index, Middle, and Ring fingers with reference to the Index-Middle interdigital crotch: method PM, based on the population mean, and method PR, which also considers the Hand Width. The overall average estimation error for method PM is 1.87 mm, while for method PR it is 1.69 mm. Method PR compared to method PM improves the precision by up to 32% in the x direction and 3% in the y direction. Based on these results, a 3D CAD hand model representing the target population was developed, which can be used for the design of population-specific ergonomic medical devices.

关键词： dentistry   orthodontics   biomechanics   cementation   brackets   thermocycling   aging  

摘要： Objective: The objective of this study was to evaluate the effect of different surface treatment methods on the shear bond strength (SBS) of metal brackets bonded to two types of CAD/CAM composite restorations: milled and 3D-printed. Materials and Methods: A total of 160 flat-shaped specimens (10 x 10 x 2 mm3) were prepared from four different CAD/CAM composites;two milled (Lava Ultimate (TM) [LU] and Grandio (TM) [GR]) and two 3D-printed (Crowntec (TM) [CT] and C&B Permanent (TM) [CB]). These specimens underwent thermocycling (5000 cycles at 5-55 degrees C), then were categorized based on the surface treatment into four groups (n = 10): Group C (control, no surface treatment), Group HF (treated with 9.6% hydrofluoric acid), Group DB (mechanical roughening by a diamond bur), and Group SB (sandblasting using aluminum oxide). Metal brackets were bonded using Transbond XT Primer and universal adhesive, stored in artificial saliva for 24 h, then thermocycled again. Shear bond strength (SBS) was tested using a universal testing machine until bracket debonding occurred. The adhesive remnant index (ARI) was assessed using a stereomicroscope to quantify the residual adhesive following debonding. Result: Regarding material, GR and LU restorations had significantly higher SBS values compared to CT and CB, ranging from 13.90 MPa to 20.35 MPa. Regarding surface treatment, SB and HF groups showed significantly higher SBS values. The ARI scores showed different adhesive modes of failure, with higher instances of scores 0 and 1, which indicate no or minimal adhesive remaining. Conclusions: Both milled and 3D-printed materials had adequate SBS for clinical use, with milled materials showing superior results. Surface treatments like sandblasting and HF significantly improved bond strength, with adhesive failure being common.

关键词： Coronary artery disease   CAD   proprotein convertase subtilisin   kexin type 9   PCSK9   low density lipoprotein cholesterol   polymorphism  

摘要： Objective Coronary artery disease (CAD) is the leading cause of morbidity and mortality in the world. The proprotein convertase subtilisin/kexin type 9 (PCSK9) E670G polymorphism has been reported to be associated with variability in levels of low density lipoprotein cholesterol, a risk factor for CAD. However, the relationship between PCSK9 E670G and CAD is still not fully elucidated. Methods A total of 225 patients and 189 control subjects were recruited in this study. DNA was extracted from peripheral blood samples and was genotyped by mass array method. In addition, we also conducted a meta-analysis of case-control studies to elucidate the relationship of CAD and polymorphism. Results The GG genotype of PCSK9 E670G was associated with a higher risk of CAD [odds ratio (OR) 2.994, 95% confidence interval (CI): 1.174-7.631], even adjusting for risk factors (OR 2.794, 95% CI: 1.215-7.460). Logistic regression analysis showed that the dominant genetic model increased the CAD risk (OR 2.313, 95% CI: 1.070-6.983) after adjusting the confounding factors. Meta-analysis results of 13 studies revealed that PCSK9 E670G polymorphism was correlated with CAD risk under different genetic models. Conclusion Our results demonstrated that PCSK9 E670G genotype was associated with a high risk of CAD.

关键词： Airplanes   Companies   Aerodynamics   Solid modeling   Engineering drawings   Computational modeling   Geometry   Automotive components   Atmospheric modeling   Wind tunnels   Aerospace electronics   Aerospace engineering   Design automation   CADCAM   Product design   Product development  

摘要： Application programs to improve the quality and performance of its aerospace products are a critical part of Boeing's computing environment. This article focuses first on how the company developed its own modeling, manufacturing, and engineering programs and also built custom software to address shortcomings in commercial, off-the-shelf systems. The second part details Boeing's attempt to produce its own computer-aided design system. That system was intended to meet the company's internal needs and eventually become marketable to external companies. Ultimately, Boeing abandoned the new system, despite technological advances, because it failed to meet functionality, scale, and performance requirements.