Study of wound healing dynamics by single pseudo-particle tracking in phase contrast images acquired in time-lapse

Cellular contacts modify the way cells migrate in a cohesive group with respect to a free single cell. The resulting motion is persistent and correlated, with cells’ velocities self-aligning in time. The presence of a dense agglomerate of cells makes the application of single particle tracking techniques to define cells dynamics difficult, especially in the case of phase contrast images. Here, we propose an original pipeline for the analysis of phase contrast images of the wound healing scratch assay acquired in time-lapse, with the aim of extracting single particle trajectories describing the dynamics of the wound closure. In such an approach, the membrane of the cells at the border of the wound is taken as a unicum, i.e., the wound edge, and the dynamics is described by the stochastic motion of an ensemble of points on such a membrane, i.e., pseudo-particles. For each single frame, the pipeline of analysis includes: first, a texture classification for separating the background from the cells and for identifying the wound edge; second, the computation of the coordinates of the ensemble of pseudo-particles, chosen to be uniformly distributed along the length of the wound edge. We show the results of this method applied to a glioma cell line (T98G) performing a wound healing scratch assay without external stimuli. We discuss the efficiency of the method to assess cell motility and possible applications to other experimental layouts, such as single cell motion. The pipeline is developed in the Python language and is available upon request

Artificial intelligence-based models for reconstructing the critical current and index-value surfaces of HTS tapes

For modelling superconductors, interpolation and analytical formulas are commonly used to consider the relationship between the critical current density and other electromagnetic and physical quantities. However, look-up tables are not available in all modelling and coding environments, and interpolation methods must be manually implemented. Moreover, analytical formulas only approximate real physics of superconductors and, in many cases, lack a high level of accuracy. In this paper, we propose a new approach for addressing this problem involving artificial intelligence (AI) techniques for reconstructing the critical surface of high temperature superconducting (HTS) tapes and predicting their index value known as n-value. Different AI models were proposed and implemented, relying on a public experimental database for electromagnetic specifications of HTS tapes, including artificial neural networks (ANN), eXtreme Gradient Boosting (XGBoost), and kernel ridge regressor (KRR). The ANN model was the most accurate in predicting the critical current of HTS materials, performing goodness of fit very close to 1 and extremely low root mean squared error. The XGBoost model proved to be the fastest method, with training computational times under 1 s; whilst KRR could be used as an alternative solution with intermediate performance

Study of Wound Healing Dynamics by Single Pseudo-Particle Tracking in Phase Contrast Images Acquired in Time-Lapse

Cellular contacts modify the way cells migrate in a cohesive group with respect to a free single cell. The resulting motion is persistent and correlated, with cells’ velocities self-aligning in time. The presence of a dense agglomerate of cells makes the application of single particle tracking techniques to define cells dynamics difficult, especially in the case of phase contrast images. Here, we propose an original pipeline for the analysis of phase contrast images of the wound healing scratch assay acquired in time-lapse, with the aim of extracting single particle trajectories describing the dynamics of the wound closure. In such an approach, the membrane of the cells at the border of the wound is taken as a unicum, i.e., the wound edge, and the dynamics is described by the stochastic motion of an ensemble of points on such a membrane, i.e., pseudo-particles. For each single frame, the pipeline of analysis includes: first, a texture classification for separating the background from the cells and for identifying the wound edge; second, the computation of the coordinates of the ensemble of pseudo-particles, chosen to be uniformly distributed along the length of the wound edge. We show the results of this method applied to a glioma cell line (T98G) performing a wound healing scratch assay without external stimuli. We discuss the efficiency of the method to assess cell motility and possible applications to other experimental layouts, such as single cell motion. The pipeline is developed in the Python language and is available upon request.Basque Government BERC 2018– 2021 Spanish Ministry of Economy and Competitiveness MINECO via the BCAM Severo Ochoa SEV-2017-0718 accreditatio

Stabilità chimica e microbiologica di sciroppi zuccherini sottoposti a lunga conservazione

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In vitro 2D and 3D roughness and spectrophotometric and gloss analyses of ceramic materials after polishing with different prophylactic pastes

Statement of problem: The effect of prophylactic polishing pastes on composite resin materials has been extensively investigated, but little is known about their effect on ceramic materials. Purpose: The purpose of this in vitro study was to evaluate the effect of prophylactic polishing pastes on the 2D and 3D roughness, translucency, and gloss of different ceramic materials. Material and methods: A total of 120 flat specimens (thickness: 2 mm) obtained from computer-aided design and computer-aided manufacturing (CAD-CAM) blocks of leucite glass-ceramic (Empress CAD), lithium disilicate glass-ceramic (e.max CAD), and zirconia (Zenostar MT) were glazed and sintered. Forty specimens from each material were then divided into 4 groups and polished with Cleanic fine, Nupro fine, or Proxyt fine pastes, leaving the control group untreated. The specimens were polished for 2 minutes with a prophylaxis cup mounted on a handpiece, applying a constant load of 3.9 N at 2000 rpm. Surface roughness was measured by using a contact profilometer and a 3D optical profilometer. The translucency parameter and gloss value were calculated by using a spectrophotometer and a glossmeter. One specimen per group was observed by scanning electron microscopy at 7200 magnification. Differences in means were compared by using 2-way ANOVA followed by the Tukey honestly significant difference (HSD) test (\u3b1=.05). Results: The 2D roughness of Empress was lower than that of e.max (P<.05) and was increased by using Cleanic fine and Nupro fine pastes (P<.05). The translucency parameter values of Empress and Zenostar decreased with the use of Nupro fine paste (P<.05). Zenostar showed the lowest translucency (P<.05). The effect of prophylactic polishing pastes on gloss was minimal (P>.05). The gloss of Empress was higher than that of Zenostar and e.max (P<.05). The Pearson correlation showed that gloss and surface roughness were correlated (P<.001). Conclusions: Polishing procedures can alter the surface of a ceramic restoration

Digital bar prototype technique for full-arch rehabilitation on implants

Background and Overview: The aim of the authors in this case report was to describe a new approach to using the digital bar prototype technique for complete digital full-arch implant rehabilitation. Two combinable structures were used during the same visit as prototypes to simultaneously test the implant locations and the prosthetic parameters. Then the structures were joined together to form the final prosthesis. Case Description: After the implant integration with the immediate provisional restoration, 3 sets of digital impressions were obtained to obtain a master digital model (MDM). A stereolithographic model with implant analogs was printed on the basis of the MDM. A titanium bar with implant connections and a functional resin structure were milled on the basis of the MDM and used as prototypes. To check the accuracy of the implant impression, the titanium prototype was tried in, and clinical and radiographic tests were performed. Then the resin prototype was slid into the positional prototype and fitted to the patient, and the esthetic and occlusal properties were evaluated and refined. Definitive restoration was obtained by luting the 2 prototypes together and finalizing the prosthesis with pink resin. Conclusions and Practical Implications: The prototypes allowed the clinician to simultaneously verify the accuracy of the digital impressions and test the prosthetic parameters in 1 visit. Moreover, they were used to create the final restoration. The digital bar prototype technique also allowed for the reduction of clinical and laboratory time in a full-arch rehabilitation on implants. Nevertheless, obtaining a full-arch impression in an edentulous arch can be challenging, and further studies are necessary to evaluate the long-term success of this technique

Manufacturing of Metal Frameworks for Full-Arch Dental Restoration on Implants: A Comparison between Milling and a Novel Hybrid Technology

Purpose: To determine the trueness and precision of frameworks manufactured with a selective laser melting/milling hybrid technique (SLM/m) and conventional milling by comparing the implant-platform/framework interface with those of the original computer-aided design (CAD). Materials and Methods: Using a virtual 6-implant-supported full-arch framework CAD drawing, 27 titanium replicas were manufactured by 3 independent manufacturing centers (n = 9/center) using a hybrid SLM/m technology (labs 1 and 2) or the conventional milling technique (lab 3). Using an opto-mechanical coordinate measuring machine, the frameworks\u2019 misfit distribution and patterns were analyzed, and the position error between paired platform positions within each framework was evaluated to calculate the misfit tendency for each group. A multilevel analysis using a mixed-effects model was conducted (\u3b1 = 0.05). The trueness was evaluated as the dimensional difference from the original, while the precision as the dimensional difference from a repeated scan. Results: The 3 dimensional misfits differed significantly among the 3 groups, with the milled group exhibiting the least accurate outcome (p = 0.005). The mean 3D positioning errors ranged from 8 to 16 \ub5m and from 9 to 22 \ub5m for the SLM/m technique (labs 1 and 2, respectively), and from 20 to 35 \ub5m for conventional milling (lab 3). Regarding the misfit distribution pattern, the misfit increased with the distance between paired platform positions in all groups. Conclusions: All groups had 3D misfits well within the error limits reported in the literature. The 3D misfits of new hybrid (SLM/milling) and conventional (milling) procedures differed significantly among them, with the milling technique the less accurate and precise. The largest errors in all groups were found between the most distant implants, resulting in a correlation between the framework span and the inaccuracies

Manufacturing of Metal Frameworks for Full-Arch Dental Restoration on Implants: A Comparison between Milling and a Novel Hybrid Technology

Purpose: To determine the trueness and precision of frameworks manufactured with a selective laser melting/milling hybrid technique (SLM/m) and conventional milling by comparing the implant-platform/framework interface with those of the original computer-aided design (CAD). Materials and Methods: Using a virtual 6-implant-supported full-arch framework CAD drawing, 27 titanium replicas were manufactured by 3 independent manufacturing centers (n = 9/center) using a hybrid SLM/m technology (labs 1 and 2) or the conventional milling technique (lab 3). Using an opto-mechanical coordinate measuring machine, the frameworks\u2019 misfit distribution and patterns were analyzed, and the position error between paired platform positions within each framework was evaluated to calculate the misfit tendency for each group. A multilevel analysis using a mixed-effects model was conducted (\u3b1 = 0.05). The trueness was evaluated as the dimensional difference from the original, while the precision as the dimensional difference from a repeated scan. Results: The 3 dimensional misfits differed significantly among the 3 groups, with the milled group exhibiting the least accurate outcome (p = 0.005). The mean 3D positioning errors ranged from 8 to 16 \ub5m and from 9 to 22 \ub5m for the SLM/m technique (labs 1 and 2, respectively), and from 20 to 35 \ub5m for conventional milling (lab 3). Regarding the misfit distribution pattern, the misfit increased with the distance between paired platform positions in all groups. Conclusions: All groups had 3D misfits well within the error limits reported in the literature. The 3D misfits of new hybrid (SLM/milling) and conventional (milling) procedures differed significantly among them, with the milling technique the less accurate and precise. The largest errors in all groups were found between the most distant implants, resulting in a correlation between the framework span and the inaccuracies