Blowup of solution for a reaction diffusion equation with memory and multiple nonlinearities

In this paper, the blow-up of solution for the initial boundary value problem of a class of reaction diffusion equation with memory and multiple nonlinearities is studied. Using a differential inequalities, we obtain sufficient conditions for the blow-up of solutions in a finite time interval under suitable conditions on memory and nonlinearities term and for vanishing initial energy

Task-Driven Causal Feature Distillation: Towards Trustworthy Risk Prediction

Since artificial intelligence has seen tremendous recent successes in many areas, it has sparked great interest in its potential for trustworthy and interpretable risk prediction. However, most models lack causal reasoning and struggle with class imbalance, leading to poor precision and recall. To address this, we propose a Task-Driven Causal Feature Distillation model (TDCFD) to transform original feature values into causal feature attributions for the specific risk prediction task. The causal feature attribution helps describe how much contribution the value of this feature can make to the risk prediction result. After the causal feature distillation, a deep neural network is applied to produce trustworthy prediction results with causal interpretability and high precision/recall. We evaluate the performance of our TDCFD method on several synthetic and real datasets, and the results demonstrate its superiority over the state-of-the-art methods regarding precision, recall, interpretability, and causality.Comment: Proceedings of the 2024 AAAI Conference on Artificial Intelligenc

Experimental study on the hydrodynamic behaviour of an FPSO in a deepwater region of the Gulf of Mexico

As offshore oil and gas exploration moves progressively toward greater water depths, it becomes more challenging to predict the environmental forces and global responses of floating production storage and offloading (FPSO) systems and the dynamic behaviour of the mooring lines and risers. The validation of complex numerical models through scale model experimental testing is restricted by the physical limits of the test facilities. It is not feasible to install the equivalent full length mooring lines and riser systems and select an appropriate scale model for reducing the uncertainties in the experimental test programme for deepwater and ultra-deepwater conditions. The combination of an appropriate scale FPSO model with a suitable level of equivalent effect reduced depth using a hybrid passive truncated experimental methodology for the mooring lines and risers is a practical approach. Following recent discoveries, FPSO has been proposed for a portion of the planned development in the southern Gulf of Mexico (GOM) in water depth ranging from 1000 to 2000 m. Based on a scale model and a hybrid passive truncated experimental method for mooring lines and risers, this paper investigates the global response of an FPSO, as well as the dynamics of mooring lines and risers in the context of prevailing environmental conditions for field development in a specific deepwater location in GOM. The experiments revealed that the main horizontal motion response of the FPSO (surge) under non-collinear loading condition is almost two-times that of the collinear loading condition. The mooring lines in the non-collinear condition are more sensitive to the dynamic response and risers appear to have an important influence on the low frequency damping

Direct conversion of astrocytes into neuronal cells by drug cocktail

Direct conversion of astrocytes into neuronal cells by drug cocktail Cell Research advance online publication 2 October 2015; doi:10.1038/cr.2015.120 Dear Editor, Neurological disorder is one of the greatest threats to public health according to the World Health Organization. Because neurons have little or no regenerative capacity, conventional therapies for neurological disorders yielded poor outcomes. While the introduction of exogenous neural stem cells or neurons holds promise, many challenges still need to be tackled, including cell resource, delivery strategy, cell integration and cell maturation. Reprogramming of fibroblasts into induced pluripotent stem cells or directly into desirable neuronal cells by transcription factors (TFs) or small molecules can solve some problems, but other issues remain to be addressed, including safety, conversion efficiency and epigenetic memory [1, 2]. Astrocytes are considered to be the ideal starting candidate cell type for generating new neurons, due to their proximity in lineage distance to neurons and ability to proliferate after brain damage. Many studies have already revealed that astrocytes of the central nervous system can be reprogrammed into induced neuronal cells by virus-mediated overexpression of specific TFs in vitro and in vivo [3-6]. However, application of this virus-mediated direct conversion is still limited due to concerns on clinical safety. We have previously reported direct conversion of somatic cells into neural progenitor cells (NPCs) in vitro by cocktail of small molecules under hypoxia [7]. Here we set out to explore whether astrocytes can be induced into neuronal cells by the chemical cocktail in vitro

Multidimensional features of sporadic Creutzfeldt-Jakob disease in the elderly: a case report and systematic review

BackgroundAs a rare neurodegenerative disease, sporadic Creutzfeldt-Jakob disease (sCJD) is poorly understood in the elderly populace. This study aims to enunciate the multidimensional features of sCJD in this group.MethodsA case of probable sCJD was reported in a 90-year-old Chinese man with initial dizziness. Then, available English literature of the elderly sCJD cases (aged 80 years and over) was reviewed and analyzed. Patients (15 cases) were subdivided and compared geographically.ResultsIn the elderly sCJD cohort, the onset age was 84.9 ± 4.5 years and the median disease duration was 6.8 months, with respiratory infection/failure as the commonest death cause. Various clinical symptoms were identified, with cognitive disorder (86.7%) as the commonest typical symptom and speech impairment (66.7%) as the most atypical one. Restricted hyperintensities were reported in 60.0% cases on DWI, periodic sharp wave complexes in 73.3% cases on electroencephalogram, and cerebral hypoperfusion/hypometabolism in 26.7% cases on molecular imaging. The sensitive cerebrospinal fluid biomarkers were total tau (83.3%), 14-3-3 protein (75.0%), and PrP RT-QuIC (75.0%). Neuropathological profiles in the cerebral cortex revealed vacuolar spongiosis, neuronal loss, gliosis, and aging-related markers, with synaptic deposit as the commonest PrP pattern (60.0%). The polymorphic PRNP analysis at codon 129 was M/M (90.9%), with MM1 and MM2C as the primary molecular phenotypes. Latency to first clinic visit, hyperintense signals on DWI, and disease duration were significantly different between the patient subgroups.ConclusionThe characteristics of sCJD are multidimensional in the elderly, deepening our understanding of the disease and facilitating an earlier recognition and better care for this group

Clay mineral transformation mechanism modelling of shale reservoir in Da’anzhai Member, Sichuan Basin, Southern China

Shale reservoirs often undergo intense clay mineral transformation, which plays a crucial role in the formation and evolution of pores. The reservoir lithofacies types of Da’anzhai Member in the Sichuan Basin are complex, the heterogeneity is strong, and the transformation mechanism of clay minerals is unclear, limiting the understanding of reservoir diagenesis and reservoir formation mechanism. In this study, we selected the typical shale reservoir in the Da’anzhai Member of the eastern Sichuan Basin and innovatively introduced the multiphase fluid-chemical-thermal multi-field coupled numerical simulation technique to focus on the dissolution, precipitation and transformation laws of diagenetic minerals in the shale reservoir. We calculated the transformation of diagenetic minerals and their physical response under different temperatures, pressure and fluid conditions and identified the main controlling factors of mineral transformation in shale reservoirs in the study area. The results show that the transformation of smectite to illite in the Da’anzhai Member is a complex physicochemical process influenced by various factors such as temperature, pressure, fluid, and lithology. The increase in temperature can promote illitization until the critical temperature of 110°C–115°C, below which the conversion rate of smectite to illite increases as the temperature increases. However, when it is higher than the critical temperature, the degree of illitization decreases. In specific K-rich fluids, organic acids significantly affect the conversion of clay minerals in the Da’anzhai Member of the formation. The acidic fluid promotes the dissolution of minerals such as K-feldspar and releases K+, thus provides the material basis for illitization. The research results provide theoretical support for the diagenetic and formation mechanism of the shale reservoir in the Da’anzhai Member of the Sichuan Basin and even for the efficient exploration and development of shale gas