Effect of mesenchymal stem cell-incorporated hydroxyapatite-collagen scaffold on tissue repair in acute spinal cord injury, and the mechanism involved

Purpose: To study the effect of hydroxyapatite-collagen (HC) scaffold with mesenchymal stem cells (MSCs) on tissue repair in acute spinal cord  injury (SCI).Method: Adult female Sprague-Dawley rats weighing 200 - 230 g were randomly divided into two groups implanted either with bone marrow-MSCs (experimental group) or HC scaffold alone (control group). Spinal cord injury was induced using laminectomy, resulting in a 2.0-mm gap at T10 of the spinal cord. The gap was filled in both groups with 2-mm HC scaffold at day 10 of culture. Cellular development, viability, and proliferation inside the scaffold were determined. Angiogenesis was determined by measuring fibronectin (FN) immunofluorescence, von Willebrand factor (vWF), hypoxiainducible factor 1-alpha (HIF-1α) and vascular endothelial growth factor (VEGF).Results: HC scaffold strengthened MSCs. Bone marrow MSCs exhibited no statistically significant difference when compared with cells in culture at day 10 (47.03 ± 3.135 %, p > 0.05). Moreover, on days 5 and 10, FN deposition was higher in MSCs with scaffold than in scaffold-free MSCs. The expressions of FN, vWF, HIF-1α and VEGF were positively correlated, indicating that incorporation of HC scaffold into MSCs significantly improved tissue repair by improving angiogenesis via a differentiation process (p < 0.001).Conclusion: These findings suggest that HC scaffold with MSCs is a potential therapeutic procedure for spinal cord injury. Keywords: Mesenchymal stem cells, Hydroxyapatite-collagen, Spinal cord injury, HC scaffol

Going Back to Basics: The challenges and limitations of teaching Space Syntax through short course programs within mainland China

Within recent years Space Syntax theory has continued to enjoy an ongoing growth of interest from mainland Chinese higher education establishments. Academics, students and professionals alike have been given access to an extensive knowledge base through online accessibility and numerous conference events, including the 12the Space Syntax Symposium held in Beijing in 2019 and the 6th Chinese Space Syntax Symposium held in Guangzhou in 2021. In addition, Tongji University now offers a master’s program specifically tailored to delivering space syntax theory. However, the authors suggest that beyond the mainstream academic circles, an awareness of Space Syntax theory remains relatively limited within both more local Schools of Architecture and Local Design Institutes (LDI’s). As the idea of teaching research-based design becomes more popular (Karimi 2019) and the argument for evidence-based design gains a stronger footing within the industry, this paper proposes that through the use of tailored short course programs it may be possible to extend the knowledge of Space Syntax to undergraduates and postgraduates within a broader scope. A more comprehensive understanding and practical application of this theory can be developed by extrapolating key core principles and delivering these through an abridged short course program to architectural and urban design students. This paper outlines the structure of the space syntax program developed to be delivered to the students at Hunan University and Changsha University of Science and Technology, highlighting the limitations and challenges of this pedagogical approach. It takes a number of real-time projects to which students have applied this knowledge and highlights how effective these methods are when utilized by students within their own design and research work. Results from these courses see an enhanced understanding of socio/spatial relations amongst participants, with students implementing analysis and predictive modelling methods to add an additional layer of scientific rigour into their own work. This often translates into improvements within their approach to design, seeing an increasing willingness to adopt a more evidence-based approach to their own work

Discrete Conditional Diffusion for Reranking in Recommendation

Reranking plays a crucial role in modern multi-stage recommender systems by rearranging the initial ranking list to model interplay between items. Considering the inherent challenges of reranking such as combinatorial searching space, some previous studies have adopted the evaluator-generator paradigm, with a generator producing feasible sequences and a evaluator selecting the best one based on estimated listwise utility. Inspired by the remarkable success of diffusion generative models, this paper explores the potential of diffusion models for generating high-quality sequences in reranking. However, we argue that it is nontrivial to take diffusion models as the generator in the context of recommendation. Firstly, diffusion models primarily operate in continuous data space, differing from the discrete data space of item permutations. Secondly, the recommendation task is different from conventional generation tasks as the purpose of recommender systems is to fulfill user interests. Lastly, real-life recommender systems require efficiency, posing challenges for the inference of diffusion models. To overcome these challenges, we propose a novel Discrete Conditional Diffusion Reranking (DCDR) framework for recommendation. DCDR extends traditional diffusion models by introducing a discrete forward process with tractable posteriors, which adds noise to item sequences through step-wise discrete operations (e.g., swapping). Additionally, DCDR incorporates a conditional reverse process that generates item sequences conditioned on expected user responses. Extensive offline experiments conducted on public datasets demonstrate that DCDR outperforms state-of-the-art reranking methods. Furthermore, DCDR has been deployed in a real-world video app with over 300 million daily active users, significantly enhancing online recommendation quality

An Evaluation on Bridge Bearing Capacity under Scour and Re-occurrence of Strong Earthquake

Plagued by frequent calamities, Bridge No.3 encountered magnitude-8 earthquake on May 12, 2008 and several years later its pile foundation was intensively scoured. The smallest scour depth was 4.5 meters and the largest scour depth was 9.2 meters. Considering intense scour and re-occurrence of strong earthquake, the Chinese existing standard and seismic response analysis are used to study bearing capacity and seismic performance of pier and pile foundation of Bridge No.3 before and after scour. It is proved by calculation that the bridge is stable before scour and can hardly bear strong earthquake and intense scour after scour, therefore consolidation is required. The study result may serve as an important reference for the bridge affected by serious scour and strong earthquake

ConPET: Continual Parameter-Efficient Tuning for Large Language Models

Continual learning necessitates the continual adaptation of models to newly emerging tasks while minimizing the catastrophic forgetting of old ones. This is extremely challenging for large language models (LLMs) with vanilla full-parameter tuning due to high computation costs, memory consumption, and forgetting issue. Inspired by the success of parameter-efficient tuning (PET), we propose Continual Parameter-Efficient Tuning (ConPET), a generalizable paradigm for continual task adaptation of LLMs with task-number-independent training complexity. ConPET includes two versions with different application scenarios. First, Static ConPET can adapt former continual learning methods originally designed for relatively smaller models to LLMs through PET and a dynamic replay strategy, which largely reduces the tuning costs and alleviates the over-fitting and forgetting issue. Furthermore, to maintain scalability, Dynamic ConPET adopts separate PET modules for different tasks and a PET module selector for dynamic optimal selection. In our extensive experiments, the adaptation of Static ConPET helps multiple former methods reduce the scale of tunable parameters by over 3,000 times and surpass the PET-only baseline by at least 5 points on five smaller benchmarks, while Dynamic ConPET gains its advantage on the largest dataset. The codes and datasets are available at https://github.com/Raincleared-Song/ConPET.Comment: 12 pages, 3 figures. This work has been submitted to the IEEE for possible publication. Copyright may be transferred without notice, after which this version may no longer be accessibl

Structural and Functional Alterations in Visual Pathway After Optic Neuritis in MOG Antibody Disease: A Comparative Study With AQP4 Seropositive NMOSD

Background: Optic neuritis (ON) is an important clinical manifestation of neuromyelitis optic spectrum disease (NMOSD). Myelin oligodendrocyte glycoprotein (MOG) antibody-related and aquaporin 4 (AQP4) antibody-related ON show different disease patterns. The aim of this study was to explore the differences in structure and function of the visual pathway in patients with ON associated with MOG and AQP4 antibodies.Methods: In this prospective study, we recruited 52 subjects at Beijing Tiantan Hospital, including 11 with MOG Ig+ ON (MOG-ON), 13 with AQP4 Ig+ ON (AQP4-ON), and 28 healthy controls (HCs). Fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD) of optic radiation (OR), primary visual cortex volume (V1), brain volume, and visual acuity (VA) were compared among groups. A multiple linear regression was used to explore associations between VA and predicted factors. In addition, we used optical coherence tomography (OCT) to examine thickness of the peripapillary retinal nerve fiber layer (pRNFL) and retinal ganglion cell complex (GCC) in a separate cohort consisting of 15 patients with ON (8 MOG-ON and 7 AQP4-ON) and 28 HCs.Results: Diffusion tensor imaging showed that the FA of OR was lower than controls in patients with AQP4-ON (p = 0.001) but not those with MOG-ON (p = 0.329) and was significantly different between the latter two groups (p = 0.005), while V1 was similar in patients with MOG-ON and AQP4-ON (p = 0.122), but was lower than controls in AQP4-ON (p = 0.002) but not those with MOG-ON (p = 0.210). The VA outcomes were better in MOG-ON than AQP4-ON, and linear regression analysis revealed that VA in MOG-ON and AQP4-ON was both predicted by the FA of OR (standard β = −0.467 and −0.521, p = 0.036 and 0.034). Both patients of MOG-ON and AQP4-ON showed neuroaxonal damage in the form of pRNFL and GCC thinning but showed no statistically significant difference (p = 0.556, 0.817).Conclusion: The structural integrity of OR in patients with MOG-ON, which is different from the imaging manifestations of AQP4-ON, may be a reason for the better visual outcomes of patients with MOG-ON