Science Progress最新文献

In this study, analytical models and numerical finite element analysis (FEA) were used to accurately determine the interphase properties and elastic modulus of both untreated and esterified cellulose nanocrystals (CNC)/epoxy bio-nanocomposites. This was achieved by incorporating an interphase region around the CNC particles, with properties that vary between those of the nanofiller and the matrix. Experimental techniques for measuring interphase properties, such as atomic force microscopy and nanoindentation, are useful but sensitive to sample preparation and limited to certain materials, which makes modelling a valuable alternative. Random 2D and 3D representative volume elements (RVEs) were generated using Digimat-FE and imported into ANSYS to determine the behaviour of nanocomposite under load. The elastic moduli values from analytical and FEA models, which included the interphase region, fell within the range of experimental variation. The results showed that the modulus increased with CNC loading from 2.5 wt% to 5 wt% and that nanofiller treatment enhanced the modulus and increased the interphase thickness. For excessive esterification, there was a weakening effect on the composite that the analytical models failed to accurately predict. ANSYS response surface optimization was used to determine the optimal geometries and material properties for the FEA model, leading to accurate behaviour. Latin hypercube sampling (LHS) was used to explore the design space, and the optimal geometry was identified with a 6 nm interphase thickness, an aspect ratio of 10, a CNC modulus of 0.66 MPa, and an interphase modulus of 1.28 GPa. The 2D FEA RVE models struck a balance between accuracy and computational costs for treated nanoparticles.

The main challenge facing current energy management strategies for extended-range electric vehicles is effectively balancing power demand and energy utilization to enhance fuel economy under complex and variable driving conditions. Therefore, to optimize the distribution between the two energy sources of extended-range electric vehicles and improve their fuel economy, this paper proposes an energy management strategy incorporating speed prediction. Firstly, the long short-term memory neural network speed prediction scheme is investigated, and its effectiveness under different cyclic conditions is verified. Secondly, the four hyperparameters of the long short-term memory neural network structure were optimized using the sparrow algorithm (SA) to further enhance the prediction accuracy of the long short-term memory speed prediction algorithm. After optimization, the mean square deviation and mean absolute error are reduced by 46.46% and 54.46%, respectively, compared with the pre-optimization period. Finally, an energy management strategy based on speed prediction was designed using the sparrow algorithm-long short-term memory model. The results show that the speed prediction-based energy management strategy reduces fuel consumption by 6.05% and 3.50% under the New European Driving Cycle and World Light Vehicle Test Cycle conditions, respectively, compared to the rule-based hybrid control strategy.

Objective: Endometrial cancer (EC) is a malignant tumor with various histological subtypes and molecular phenotypes. The evaluation of drug resistance is important for cancer treatment. Progesterone resistance is the major challenge in EC. Knowledge of drug resistance in EC is important in the development of novel therapies.

Methods: In this study, ten paracancerous and ten tumor tissues were collected to measure the expression of insulin-like growth factor 2 mRNA binding protein 3 (IGF2BP3) and high-mobility group protein 1 (HMGA1). AN3CA and Ishikawa cells were used to explore the effects of IGF2BP3 on EC.

Results: The expression levels of IGF2BP3 and HMGA1 were higher in EC tumor tissues than in paracancerous tissues. IGF2BP3 and HMGA1 are highly expressed in cisplatin-resistant EC cells. IGF2BP3 knockdown decreased the growth of cisplatin-resistant EC cells. Knockdown of IGF2BP3 decreased the level of HMGA1 protein. HMGA1 knockdown decreased the growth of cisplatin-resistant EC cells.

Discuss and conclusions: The findings demonstrate that IGF2BP3 is upregulated in EC and closely regulates the growth of drug-resistant EC cells via HMGA1. The findings will inform the development of novel therapies for EC.

Background: Retail involves directly delivering goods and services to end consumers. Natural disasters and epidemics/pandemics have significant potential to disrupt supply chains, leading to shortages, forecasting errors, price increases, and substantial financial strains on retailers. The COVID-19 pandemic highlighted the need for retail sectors to prepare for crisis impacts on sales forecasts by regularly assessing and adjusting sales volumes, consumer behavior, and forecasting models to adapt to changing conditions.

Methods: This study explores strategies for adapting sales forecasts and retail approaches in response to such crises. By employing different machine learning (ML) methods, we analyze consumer behavior changes and sales impacts across various product categories, including bottom wear, top wear, one piece, accessories, outwear, and shoes during the COVID-19 pandemic.

Results: The gradient boosting and CatBoost algorithms excelled in product groups with significant sales changes during the pandemic. The Multi-Layer Perceptron (MLP) algorithm performed well in low-volume categories like accessories and footwear. Meanwhile, MLP, LightGBM, and XGBoost were effective in medium-volume categories such as outerwear and underwear.

Conclusion: The findings highlight the efficacy of these models in adapting sales forecasts to crisis conditions, offering a practical approach to enhancing retail resilience against future disruptions. This study offers an effective approach for adapting sales forecasting to shifting consumer behaviors during crises.

Disaster environments, such as fires, distort of two-way radio communication within buildings. This article presents an experimental study on microwave attenuation based on the smoke and wall type in a disaster environment using a two-way radio with digital mobile radio communication, widely used by firefighting crews in Korea. Furthermore, we compared the microwave attenuation of the two-way radio depending on the building materials and smoke. We then present the experimental result of the microwave characteristic corresponding to the four types of walls in a specially designed anechoic chamber (3 m × 1 m × 1 m) to analyze the microwave attenuation by the building materials, with results indicating up to 82% in 200 mm thick concrete. Moreover, we evaluated the propagation attenuation based on the four types of smoke with the same density in a container space (5.8 m × 2.8 m × 2.2 m). The results showed that the microwaves were not transmitted and significantly decreased based on the building materials at 400 MHz, which is the main cause of attenuation. It shows a property of up to 36% reduction in urethane. Although the attenuation of microwaves is not significantly large according to the fuels in smoke, fuels such as urethane, plastic, and rubber have relatively small attenuation of microwaves compared to wood, and the received power corresponding to urethane in smoke decreased the most.

Objective: To evaluate management strategies of tunneled-cuffed catheters (TCCs) in hemodialysis (HD) patients with hypotension and recurrent central venous thrombosis.

Methods: We retrospectively reviewed HD patients with hypotension treated at the West China Hospital. The initial catheter tip was positioned routinely in the superior vena cava (SVC). In the event of SVC thrombosis, stenosis, or obstruction, the catheter was adjusted to right atrial (RA) or SVC and RA junction, and then inferior vena cava (IVC). If thrombi completely dissolved, catheter tips were returned to the former section. Meanwhile, patients with central venous thrombus were treated with antiplatelet therapy. We analyzed the efficacy of the management strategy in HD with hypotension and recurrent central venous thrombosis.

Results: By adjusting catheter tips following the above procedure, vascular access has persevered in all the patients. Nineteen deaths (90.5%) were recorded during a median follow-up period of 6 years. No fatal pulmonary embolism nor catheter complication-related deaths were observed. The minimal survival period after the procedure was 6 years. The catheter primary patency rates at 3, 6, and 12 months were 90.5%, 66.7%, and 38.1%, respectively. The secondary patency rates were 100.0%, 80.9%, and 57.1% at 3, 6, and 12 months, respectively.

Conclusion: The insertion of the TCCs tips initially in SVC, then adjusting in SVC and RA junction, RA and IVC successively in the event of thrombosis combined with antiplatelet therapy may be considered effective to prolong the HD vintage in patients with hypotension.

Objectives: Understanding approaches to promoting green development as well as to increasing employment in old revolutionary areas from the perspective of the "dual carbon" goals is important and, hence, needs to be studied.

Methods: Using city and enterprise panel data from 2007 to 2019, this study used a differential model to assess the impact of China's low-carbon city pilot policies on employment in old revolutionary base areas.

Results: The results showed that the low-carbon city pilot policies could significantly reduce the carbon emissions of old revolutionary base areas as well as significantly promote an improvement in employment levels. Specifically, low-carbon policies could promote the green technological innovation of enterprises and optimize the industrial structure through both output effects and factor-substitution effects to create more jobs. In addition, the impact of low-carbon city pilot policies on employment in different industries and factor intensity was heterogeneous, and the employment promotion effect was more significant in low-energy industries and non-labor-intensive enterprises.

Conclusions: The research results can enrich the theoretical basis of regional development planning in China, and provide important references that can be used to both stabilize the employment of residents and promote high-quality development in underdeveloped areas.

Aptamers have attracted exceptional attention in medical field due to their intrinsic properties equivalent to antibodies such as high target affinity, low immunogenicity and toxicity, cost-effectiveness and ease of synthesis and modification, and good stability under extreme conditions, thereby providing new avenues for basic research and clinical application. Protein tyrosine kinase 7 (PTK7) has been proved to be closely linked with the progression of many types of cancer. The aberrant expression of PTK7 has positioned it as a potential theranostic biomarker for multiple cancers. Aptamer sgc8 was initially identified for its high-affinity binding to PTK7 on the T-cell acute lymphoblastic leukemia cell line (CCRF-CEM) through cell-SELEX (systematic evolution of ligands by exponential enrichment) and subsequently has demonstrated the ability to effectively recognize many types of cancer cells that express PTK7 oncogenic target. The easily modifiable nature of sgc8 facilitates its conjugation with functional agents and drugs. This identification mode and modification approach of aptamers against cancer cells provides a potential strategy for cancer diagnosis and treatment. In this review, we discuss the potential of sgc8 aptamers in early cancer diagnosis and targeted therapy, focusing specifically on their interaction with the oncogenic biomarker PTK7.

COVID-19, caused by severe acute respiratory syndrome corona virus 2 (SARS-CoV-2), is primarily a respiratory illness but significantly affects the cardiovascular system as well. After entering the body through the respiratory tract, the virus directly and indirectly disrupts the vascular system. Vascular endothelial cells (ECs), which express ACE2 and TMPRSS2, are targets for viral invasion. However, the predominant cause of widespread vascular damage is the "cytokine storm" induced by the immune response. This leads to EC activation, inflammation, neutrophil activation, and neutrophil-platelet aggregation, causing endothelial injury. Additionally, increased expression of plasminogen activator inhibitor-1 disrupts the balance between prothrombotic and fibrinolytic processes, while activation of the renin-angiotensin-aldosterone system adds oxidative stress to the vascular endothelium. In the heart, SARS-CoV-2 invades ECs, leading to apoptosis and pyroptosis, exacerbated by inflammation and elevated catecholamines. These factors contribute to arrhythmias, strokes, and myocardial infarction in severe cases of COVID-19. This narrative review aims to explore the mechanisms by which SARS-CoV-2 affects the cardiovascular system and to highlight the resulting complications. It also identifies research gaps and discusses potential therapeutic strategies to mitigate the cardiovascular impacts of COVID-19.