Effects of culture system and hypoxia on long-term expansion and differentiation of mesenchymal stem cells derived from periodontal ligament

Periodontal ligament stem cells (PDLSCs), located in the perivascular space of the periodontium were able to differentiate into periodontal cell types in vitro [1]. In this study, we investigated the effect of three different culture media and of low oxygen tension (1%) on the immunophenotype, proliferation rate and osteogenic potential of PDLSCs. This study was the first report to compare the PDLSCs from the same person in different culture systems. PDLSCs were harvested from three healthy third molars and the single-cells suspensions were cultured in the culture media a-MEM, DMEM and a new medium formulation (Enriched Ham’s F12 Medium, EHFM), respectively. PDLSCs were subcultured (4 x 103/cm2) until passage 7. The characterization of PDLSCs included FACS, immunofluorescence analysis and cell proliferation assay in both normoxia and hypoxia (1%). After culture in osteogenic medium for 7, 14 and 21 days, osteoblastic differentiation was evaluated by alkaline phosphatase activity, mineralization (alizarin red staining) and gene expression of osteogenic markers. Osteoblastic differentiation was also evaluated under hypoxic conditions. PDLSCs cultured in EHFM showed increased proliferation rate and CD73 overexpression compared to cells maintained in a-MEM and DMEM. On the other hand, PDLSCs grown in a-MEM and DMEM showed higher osteogenic differentiation potential compared to EHFM. Hypoxia affected both proliferation rate and osteogenic potential. On the basis of these results, we propose a two stages protocol for the osteogenic induction of PDLSCs, in which the early expansion stage could be performed in EHFM without loss of cell stemness. Furthermore, the results obtained in the different conditions (normoxia and hypoxia) suggest that oxygen tension plays a critical role in PDLSCs physiology

Comparison between low-cost passive and active vision for obstacle depth

Obstacle detection is a key issue in many current applications, especially in applications that have been increasingly highlighted such as: advanced driver assistance systems (ADAS), simultaneous localization and mapping (SLAM) and autonomous navigation system. This can be achieved by active and passive acquisition vision systems, for example: laser and cameras respectively. In this paper we present a comparison between low-cost active and passive devices, more specifically LIDAR and two cameras. To this comparison a disparity map is created by stereo correspondence through two images and a point cloud map created by LIDAR data values (distances measures). The obtained results shown that passive vision can be as good as or even better than active vision in low cost scenarios

Comparison between low-cost passive and active vision for obstacle depth

Obstacle detection is a key issue in many current applications, especially in applications that have been increasingly highlighted such as: advanced driver assistance systems (ADAS), simultaneous localization and mapping (SLAM) and autonomous navigation system. This can be achieved by active and passive acquisition vision systems, for example: laser and cameras respectively. In this paper we present a comparison between low-cost active and passive devices, more specifically LIDAR and two cameras. To this comparison a disparity map is created by stereo correspondence through two images and a point cloud map created by LIDAR data values (distances measures). The obtained results shown that passive vision can be as good as or even better than active vision in low cost scenarios

Comparison between low-cost passive and active vision for obstacle depth

Obstacle detection is a key issue in many current applications, especially in applications that have been increasingly highlighted such as: advanced driver assistance systems (ADAS), simultaneous localization and mapping (SLAM) and autonomous navigation system. This can be achieved by active and passive acquisition vision systems, for example: laser and cameras respectively. In this paper we present a comparison between low-cost active and passive devices, more specifically LIDAR and two cameras. To this comparison a disparity map is created by stereo correspondence through two images and a point cloud map created by LIDAR data values (distances measures). The obtained results shown that passive vision can be as good as or even better than active vision in low cost scenarios

Colorectal Cancer Stage at Diagnosis Before vs During the COVID-19 Pandemic in Italy

IMPORTANCE Delays in screening programs and the reluctance of patients to seek medical attention because of the outbreak of SARS-CoV-2 could be associated with the risk of more advanced colorectal cancers at diagnosis. OBJECTIVE To evaluate whether the SARS-CoV-2 pandemic was associated with more advanced oncologic stage and change in clinical presentation for patients with colorectal cancer. DESIGN, SETTING, AND PARTICIPANTS This retrospective, multicenter cohort study included all 17 938 adult patients who underwent surgery for colorectal cancer from March 1, 2020, to December 31, 2021 (pandemic period), and from January 1, 2018, to February 29, 2020 (prepandemic period), in 81 participating centers in Italy, including tertiary centers and community hospitals. Follow-up was 30 days from surgery. EXPOSURES Any type of surgical procedure for colorectal cancer, including explorative surgery, palliative procedures, and atypical or segmental resections. MAIN OUTCOMES AND MEASURES The primary outcome was advanced stage of colorectal cancer at diagnosis. Secondary outcomes were distant metastasis, T4 stage, aggressive biology (defined as cancer with at least 1 of the following characteristics: signet ring cells, mucinous tumor, budding, lymphovascular invasion, perineural invasion, and lymphangitis), stenotic lesion, emergency surgery, and palliative surgery. The independent association between the pandemic period and the outcomes was assessed using multivariate random-effects logistic regression, with hospital as the cluster variable. RESULTS A total of 17 938 patients (10 007 men [55.8%]; mean [SD] age, 70.6 [12.2] years) underwent surgery for colorectal cancer: 7796 (43.5%) during the pandemic period and 10 142 (56.5%) during the prepandemic period. Logistic regression indicated that the pandemic period was significantly associated with an increased rate of advanced-stage colorectal cancer (odds ratio [OR], 1.07; 95%CI, 1.01-1.13; P = .03), aggressive biology (OR, 1.32; 95%CI, 1.15-1.53; P < .001), and stenotic lesions (OR, 1.15; 95%CI, 1.01-1.31; P = .03). CONCLUSIONS AND RELEVANCE This cohort study suggests a significant association between the SARS-CoV-2 pandemic and the risk of a more advanced oncologic stage at diagnosis among patients undergoing surgery for colorectal cancer and might indicate a potential reduction of survival for these patients

Burnout among surgeons before and during the SARS-CoV-2 pandemic: an international survey

Background: SARS-CoV-2 pandemic has had many significant impacts within the surgical realm, and surgeons have been obligated to reconsider almost every aspect of daily clinical practice. Methods: This is a cross-sectional study reported in compliance with the CHERRIES guidelines and conducted through an online platform from June 14th to July 15th, 2020. The primary outcome was the burden of burnout during the pandemic indicated by the validated Shirom-Melamed Burnout Measure. Results: Nine hundred fifty-four surgeons completed the survey. The median length of practice was 10 years; 78.2% included were male with a median age of 37 years old, 39.5% were consultants, 68.9% were general surgeons, and 55.7% were affiliated with an academic institution. Overall, there was a significant increase in the mean burnout score during the pandemic; longer years of practice and older age were significantly associated with less burnout. There were significant reductions in the median number of outpatient visits, operated cases, on-call hours, emergency visits, and research work, so, 48.2% of respondents felt that the training resources were insufficient. The majority (81.3%) of respondents reported that their hospitals were included in the management of COVID-19, 66.5% felt their roles had been minimized; 41% were asked to assist in non-surgical medical practices, and 37.6% of respondents were included in COVID-19 management. Conclusions: There was a significant burnout among trainees. Almost all aspects of clinical and research activities were affected with a significant reduction in the volume of research, outpatient clinic visits, surgical procedures, on-call hours, and emergency cases hindering the training. Trial registration: The study was registered on clicaltrials.gov "NCT04433286" on 16/06/2020

Caracterização e classificação de fatias de sistemas porosos em imagens tomográficas 3D por métodos de clusterização

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico, Programa de Pós-Graduação em Ciência e Engenharia de Materiais, Florianópolis, 2018.Rochas porosas apresentam características físicas que podem ser preditas a partir da analise de suas imagens tomográficas (MIRABOLGHASEMI et al., 2015), tradicionalmente as medições realizadas nas imagens são as de porosidade, permeabilidade e autocorrelação, que permitem prever propriedades como escoamento de fluxo através do material, ou a topologia dos poros (ADLER; JACQUIN; QUIBLIER, 1990). Porém estas características podem variar, as vezes drasticamente, dentro de uma mesma rocha, especialmente ao longo do seu eixo de formação, o qual implica em diferentes características petrofísicas. Considerando esta heterogeneidade das rochas é possível intuir que rochas completamente diferentes possam ter fatias que se comportem de forma semelhante entre si, e portanto uma forma de caracterizar e classificar estas fatias semelhantes pode trazer uma nova perspectiva ao campo de analise destes materiais. No presente trabalho um conjunto de doze imagens tomográficas de raio-X de plugs de rochas porosas foram selecionadas pela sua aparente homogeneidade, as características de suas camadas foram avaliadas, parte destes resultados foram classificados utilizando diferentes algoritmos de clusterização, e o restante dos dados foram utilizados para validar a classificação. O trabalho mostra resultados promissores, permitindo classificar com um elevado grau de certeza a qual rocha pertence uma camada.Abstract : Porous rocks present physical characteristics that can be predicted based on the analysis of their tomographic images (MIRABOLGHASEMI et al., 2015). Traditionally those images are analyzed to extract values for porosity, permeability and auto-correlation, which allows to foresee properties such as the flow of a given fluid through the material, or its pore topology (ADLER; JACQUIN; QUIBLIER, 1990). However these characteristics might change, sometimes drastically, inside the same rock, especially along its formation axis, which implies in different petrophysical characteristics. Given that these rocks are heterogeneous it s possible to realize that very different rocks can have slices that behave similarly, and thus a way to characterize and classify these similar slices can bring new insights to the way these materials are analyzed. In the current work a set of twelve x-ray tomographic images of porous rock plugs were selected for their apparent homogeneity, their characteristics were extracted by slices, part of these results were classified using different clusterization algorithms, and the remaining of the data was used for validation of the classification. The work presents promising results, allowing the classification with a high degree of certainty of which sample a given slice belongs to