CLIP2Scene: Towards Label-efficient 3D Scene Understanding by CLIP

Contrastive Language-Image Pre-training (CLIP) achieves promising results in 2D zero-shot and few-shot learning. Despite the impressive performance in 2D, applying CLIP to help the learning in 3D scene understanding has yet to be explored. In this paper, we make the first attempt to investigate how CLIP knowledge benefits 3D scene understanding. We propose CLIP2Scene, a simple yet effective framework that transfers CLIP knowledge from 2D image-text pre-trained models to a 3D point cloud network. We show that the pre-trained 3D network yields impressive performance on various downstream tasks, i.e., annotation-free and fine-tuning with labelled data for semantic segmentation. Specifically, built upon CLIP, we design a Semantic-driven Cross-modal Contrastive Learning framework that pre-trains a 3D network via semantic and spatial-temporal consistency regularization. For the former, we first leverage CLIP's text semantics to select the positive and negative point samples and then employ the contrastive loss to train the 3D network. In terms of the latter, we force the consistency between the temporally coherent point cloud features and their corresponding image features. We conduct experiments on SemanticKITTI, nuScenes, and ScanNet. For the first time, our pre-trained network achieves annotation-free 3D semantic segmentation with 20.8% and 25.08% mIoU on nuScenes and ScanNet, respectively. When fine-tuned with 1% or 100% labelled data, our method significantly outperforms other self-supervised methods, with improvements of 8% and 1% mIoU, respectively. Furthermore, we demonstrate the generalizability for handling cross-domain datasets. Code is publicly available https://github.com/runnanchen/CLIP2Scene.Comment: CVPR 202

Evaluation of Hybrid VMAT Advantages and Robustness Considering Setup Errors Using Surface Guided Dose Accumulation for Internal Lymph Mammary Nodes Irradiation of Postmastectomy Radiotherapy

ObjectivesSetup error is a key factor affecting postmastectomy radiotherapy (PMRT) and irradiation of the internal mammary lymph nodes is the most investigated aspect for PMRT patients. In this study, we evaluated the robustness, radiobiological, and dosimetric benefits of the hybrid volumetric modulated arc therapy (H-VMAT) planning technique based on the setup error in dose accumulation using a surface-guided system for radiation therapy.MethodsWe retrospectively selected 32 patients treated by a radiation oncologist and evaluated the clinical target volume (CTV), including internal lymph node irradiation (IMNIs), and considered the planning target volume (PTV) margin to be 5 mm. Three different planning techniques were evaluated: tangential-VMAT (T-VMAT), intensity-modulated radiation therapy (IMRT), and H-VMAT. The interfraction and intrafraction setup errors were analyzed in each field and the accumulated dose was evaluated as the patients underwent daily surface-guided monitoring. These parameters were included while evaluating CTV coverage, the dose required for the left anterior descending artery (LAD) and the left ventricle (LV), the normal tissue complication probability (NTCP) for the heart and lungs, and the second cancer complication probability (SCCP) for contralateral breast (CB).ResultsWhen the setup error was accounted for dose accumulation, T-VMAT (95.51%) and H-VMAT (95.48%) had a higher CTV coverage than IMRT (91.25%). In the NTCP for the heart, H-VMAT (0.04%) was higher than T-VMAT (0.01%) and lower than IMRT (0.2%). However, the SCCP (1.05%) of CB using H-VMAT was lower than that using T-VMAT (2%) as well as delivery efficiency. And T-VMAT (3.72) and IMRT (10.5).had higher plan complexity than H-VMAT (3.71).ConclusionsIn this study, based on the dose accumulation of setup error for patients with left-sided PMRT with IMNI, we found that the H-VMAT technique was superior for achieving an optimum balance between target coverage, OAR dose, complication probability, plan robustness, and complexity

Efficacy of early prone or lateral positioning in patients with severe COVID-19: a single-center prospective cohort

Abstract Background Position intervention has been shown to improve oxygenation, but its role in non-invasively ventilated patients with severe COVID-19 has not been assessed. The objective of this study was to investigate the efficacy of early position intervention on non-invasively ventilated patients with severe COVID-19. Methods This was a single-center, prospective observational study in consecutive patients with severe COVID-19 managed in a provisional ICU at Renmin Hospital of Wuhan University from 31 January to 15 February 2020. Patients with chest CT showing exudation or consolidation in bilateral peripheral and posterior parts of the lungs were included. Early position intervention (prone or lateral) was commenced for &amp;gt; 4 hours daily for 10 days in these patients, while others received standard care. Results The baseline parameters were comparable between the position intervention group (n = 17) and the standard care group (n = 35). Position intervention was well-tolerated and increased cumulative adjusted mean difference of SpO2/FiO2 (409, 95% CI 86 to 733) and ROX index (26, 95% CI 9 to 43) with decreased Borg scale (−9, 95% CI −15 to −3) during the first 7 days. It also facilitated absorption of lung lesions and reduced the proportion of patients with high National Early Warning Score 2 (≥ 7) on days 7 and 14, with a trend toward faster clinical improvement. Virus shedding and length of hospital stay were comparable between the two groups. Conclusions This study provides the first evidence for improved oxygenation and lung lesion absorption using early position intervention in non-invasively ventilated patients with severe COVID-19, and warrants further randomized trials. </jats:sec

Adenoid lymphocyte heterogeneity in pediatric adenoid hypertrophy and obstructive sleep apnea

IntroductionAdenoid hypertrophy is the main cause of obstructive sleep apnea in children. Previous studies have suggested that pathogenic infections and local immune system disorders in the adenoids are associated with adenoid hypertrophy. The abnormalities in the number and function of various lymphocyte subsets in the adenoids may play a role in this association. However, changes in the proportion of lymphocyte subsets in hypertrophic adenoids remain unclear.MethodsTo identify patterns of lymphocyte subsets in hypertrophic adenoids, we used multicolor flow cytometry to analyze the lymphocyte subset composition in two groups of children: the mild to moderate hypertrophy group (n = 10) and the severe hypertrophy group (n = 5).ResultsA significant increase in naïve lymphocytes and a decrease in effector lymphocytes were found in severe hypertrophic adenoids.DiscussionThis finding suggests that abnormal lymphocyte differentiation or migration may contribute to the development of adenoid hypertrophy. Our study provides valuable insights and clues into the immunological mechanism underlying adenoid hypertrophy

The Clustering Characteristics and Driving Mechanisms of Tourist Preference for 5A Scenic Spots from the Dynamic Spatio-Temporal Perspective: A Case of Jiangsu in Eastern Coastal Area of China

In the era of tourism 4.0, the subjective preferences and experiences of tourists directly affects the future development of scenic spots. Among them, 5A scenic spots represent China’s world-class boutique tourist scenic ranking, which pays more attention to humanization and detailing, and better reflect tourists’ general psychological demand for tourist attractions. Therefore, it becomes an important scientific issue to explore the spatial and temporal characteristics of 5A tourists’ preferences and their deeper reasons. China’s eastern coastal provinces have played a very important role in promoting regional tourism culture, promoting regional economic development, and building a strong coastal province. Taking Jiangsu as an example, this study introduces the standard deviation ellipse and kernel density estimation to explore the characteristics and trends of tourist preference clustering in 5A scenic spots and their internal and external driving mechanisms from 2012–2021, which is based on a new perspective of geotemporal dynamic analysis. The empirical results show that: (1) the network attention of 5A scenic spots in Jiangsu generally showed a “barb-type” trend in 2012–2021, the highest network attention is concentrated in April and October, accounting for 82%, and tourists pay the most attention to cultural relics scenic spots, peaking on Sunday; (2) the tourist preference for 5A scenic spots in Jiangsu shows a relative clustering distribution pattern in general, with a slightly higher clustering trend in the northwest-southeast direction than in the northeast-southwest direction. Furthermore, the nucleus of the density values range from 0 to 115.43, showing the spatial pattern of “one belt and two cores”; (3) the internal driving factors include the types, the culture nature, the characteristics nature, the spatial proximity, and the infrastructure of scenic spots, and the external driving factors include geographical location, industrial development policy, climate comfort, economic development level, traffic accessibility, and the impact of COVID-19 epidemic. On this basis, this study puts forward feasible suggestions for improving scenic area management and increasing the reception capacity, so as to provide fine scientific guidelines for the high-quality development of 5A scenic spots in Jiangsu and provide reference for further enhancing the attractiveness of 5A scenic spots and their synergistic development in the eastern coastal provinces

Testing the integration of the US and Chinese stock markets in a Fama-Frenchy framework

This paper explores the integration/segmentation between the US and Chinese stock markets. Our analysis extends the work of Jorion and Schwartz (1986) to a Fama-French framework using both Chinese and US Fama-French factors. Despite the ongoing liberalisation process in China our results support the segmentation hypothesis

Preparation of modified sodium alginate aerogel and its application in removing lead and cadmium ions in wastewater

A low-cost, environment-friendly sodium alginate-meso-2,3-dimercaptosuccinic add hybrid aerogel (SA-DMSA) was synthesized by simple chemical grafting and vacuum freeze-drying method and used to remove heavy metal ions in wastewater. The as-prepared SA-DMSA showed high affinity for heavy metal ions, such as Pb2+, Cd2+, Cu2+, Cr3+, and Co2+, and can remove >90% of the metal ions from the corresponding solution. SA-DMSA also exhibited high selectivity to Pb2+ and Cd2+, and the maximum adsorption capacities for Pb2+ and Cd2+ reached 116.4 and 91.2 mg/g, respectively. The SA-DMSA adsorbent can be regenerated by a simple one-step acid washing, and the adsorption performance remained stable after repeated use. Given its low-cost and easy-to-obtain raw materials, simple preparation process, and simple regeneration process of the adsorbent, SA-DMSA has broad application prospects in the treatment of low-concentration heavy metal ions, especially for wastewater containing Pb2+ and Cd2+. (C) 2019 Elsevier B.V. All rights reserved