113 research outputs found
A Sequential Optimization Sampling Method for Metamodels with Radial Basis Functions
Metamodels have been widely used in engineering design to facilitate analysis and optimization of complex systems that involve computationally expensive simulation programs. The accuracy of metamodels is strongly affected by the sampling methods. In this paper, a new sequential optimization sampling method is proposed. Based on the new sampling method, metamodels can be constructed repeatedly through the addition of sampling points, namely, extrema points of metamodels and minimum points of density function. Afterwards, the more accurate metamodels would be constructed by the procedure above. The validity and effectiveness of proposed sampling method are examined by studying typical numerical examples
Undersampling and Cumulative Class Re-decision Methods to Improve Detection of Agitation in People with Dementia
Agitation is one of the most prevalent symptoms in people with dementia (PwD)
that can place themselves and the caregiver's safety at risk. Developing
objective agitation detection approaches is important to support health and
safety of PwD living in a residential setting. In a previous study, we
collected multimodal wearable sensor data from 17 participants for 600 days and
developed machine learning models for predicting agitation in one-minute
windows. However, there are significant limitations in the dataset, such as
imbalance problem and potential imprecise labels as the occurrence of agitation
is much rarer in comparison to the normal behaviours. In this paper, we first
implement different undersampling methods to eliminate the imbalance problem,
and come to the conclusion that only 20\% of normal behaviour data are adequate
to train a competitive agitation detection model. Then, we design a weighted
undersampling method to evaluate the manual labeling mechanism given the
ambiguous time interval (ATI) assumption. After that, the postprocessing method
of cumulative class re-decision (CCR) is proposed based on the historical
sequential information and continuity characteristic of agitation, improving
the decision-making performance for the potential application of agitation
detection system. The results show that a combination of undersampling and CCR
improves F1-score and other metrics to varying degrees with less training time
and data used, and inspires a way to find the potential range of optimal
threshold reference for clinical purpose.Comment: 19 pages, 8 figure
Effects of pulsed electric field technology on the nutritional value and biological function of plant food
Pulsed Electric Fields (PEF) technology is an emerging non-thermal food processing technology that is widely used because of its low damage to food quality and its ability to kill harmful microorganisms in food. The oxidative stress caused by PEF results in the synthesis and accumulation of nutrients, and plant foods stimulated by PEF produce large amounts of Reactive Oxygen Species (ROS), which activate the metabolite synthesis pathway and eventually synthesize proteins, polyphenols, thioglucosides and carotenoids; ROS accumulate in the cell membrane of microorganisms and cause protein expression. The accumulation of ROS in the cell membrane of microorganisms can cause abnormal protein expression, damage the lipid layer and Deoxyribonucleic Acid (DNA), and eventually lead to microbial inactivation. PEF technology in food processing are multifaceted, enhancing both the nutritional value of food through the augmented presence of health-beneficial compounds and ensuring food safety by effectively inactivating harmful microorganisms. This innovative technology stands at the forefront of food processing solutions, promising to fulfill the growing consumer demand for foods that are not only safe and of high quality but also rich in nutritional value. PEF’s role as a cornerstone technology in the food industry heralds a new era of food processing, where nutrition and safety converge to meet the sophisticated needs of today’s consumers
Endovascular comprehensive treatment of post-traumatic superior mesenteric arteriovenous fistula: case report and literature review
BackgroundSuperior mesenteric arteriovenous fistula is a rare and difficult complication after abdominal trauma. Utilizing comprehensive endovascular treatment represents an effective approach to managing this condition.Case presentationWe report a case involving a 53-year-old female with a history of trauma who presented with complaints of abdominal pain, malaise, and melena. A computed tomographic scan revealed the presence of a superior mesenteric arteriovenous fistula. The fistula was occluded using four Interlock detachable coils, and a covered stent was positioned over the arteriovenous fistula in the superior mesenteric artery. Following endovascular treatment, the patient's abdominal pain and melena symptoms disappeared.ConclusionUtilizing covered stents and Interlock detachable coils for endovascular treatment of a superior mesenteric arteriovenous fistula proves to be both feasible and highly effective
Two-Dimensional Nature of Four-Layer Superconductors by Inequivalent Hole Distribution
The magnetization of the four-layer superconductor
CuBa_{2}Ca_{3}Cu_4O_{12-\delta} with T_c\simeq117 K is presented. The
high-field magnetization around T_c(H) follows the exact two-dimensional
scaling function given by Te\v{s}anovi\'{c} and Andreev. This feature is
contrary to the inference that the interlayer coupling becomes strong if the
number of CuO_2 planes in a unit cell increases. Also, the fluctuation-induced
susceptibility in the low-field region was analyzed by using the modified
Lawrence-Doniach model. The effective number of independently fluctuating CuO_2
layers per unit cell, g_{\rm eff}, turned out to be \simeq 2 rather than 4,
which indicated that two among the four CuO_2 layers were in states far from
their optimal doping levels. This result could explain why
CuBa_{2}Ca_{3}Cu_4O_{12-\delta} shows two-dimensional behavior.Comment: 5 pages and 4 figure
Immune-mediated inflammatory diseases and risk of venous thromboembolism: A Mendelian randomization study
IntroductionImmune-mediated inflammatory diseases (IMIDs) have been associated with an increased risk of venous thromboembolism (VTE) in multiple observational studies. However, a direct causally relation between IMIDs and VTE remains unclear to date. Here, we used Mendelian randomization (MR) analysis to investigate causal associations between IMIDs and VTE.MethodsWe collected genetic data from published genome-wide association studies (GWAS) for six common IMIDs, specifically inflammatory bowel disease (IBD), Crohn’s disease (CD), ulcerative colitis (UC), rheumatoid arthritis (RA), psoriasis (PSO), and systemic lupus erythematosus (SLE); and summary-level data for VTE, pulmonary embolism (PE), and deep vein thrombosis (DVT) from the FinnGen database. Two-sample MR analysis using inverse variance weighting (IVW) was performed to identify causal associations between IMIDs and VTE/DVT/PE, and sensitivity analyses were implemented for robustness.ResultsIVW analysis showed a causal relationship between genetically predicted UC (one type of IBD) and the risk of VTE (OR = 1.043, 95% CI: 1.013-1.073, p = 0.004) and DVT (OR = 1.088, 95% CI: 1.043-1.136, p < 0.001), but we found no evidence of causality between UC and PE (OR = 1.029, 95% CI: 0.986-1.074, p = 0.19). In addition, no associations were observed between total IBD, CD, RA, SLE, or PSO and VTE/DVT/PE. Sensitivity analysis found no evidence for horizontal pleiotropy.ConclusionThis MR study provides new genetic evidence for the causal relationship between IMIDs and the risk of VTE. Our findings highlight the importance of active intervention and monitoring to mitigate VTE risk in patients with IBD, in particular those presenting with UC
Weighted Gene Co-expression Network Analysis for RNA-Sequencing Data of the Varicose Veins Transcriptome
ObjectiveVaricose veins are a common problem worldwide and can cause significant impairments in health-related quality of life, but the etiology and pathogenesis remain not well defined. This study aims to elucidate transcriptomic regulations of varicose veins by detecting differentially expressed genes, pathways and regulator genes.MethodsWe harvested great saphenous veins (GSV) from patients who underwent coronary artery bypass grafting (CABG) and varicose veins from conventional stripping surgery. RNA-Sequencing (RNA-Seq) technique was used to obtain the complete transcriptomic data of both GSVs from CABG patients and varicose veins. Weighted Gene Co-expression network analysis (WGCNA) and further analyses were then carried out with the aim to elucidate transcriptomic regulations of varicose veins by detecting differentially expressed genes, pathways and regulator genes.ResultsFrom January 2015 to December 2016, 7 GSVs from CABG patients and 13 varicose veins were obtained. WGCNA identified 4 modules. In the brown module, gene ontology (GO) analysis showed that the biological processes were focused on response to stimulus, immune response and inflammatory response, etc. Kyoto encyclopedia of genes and genomes (KEGG) pathway analysis showed that the biological processes were focused on cytokine-cytokine receptor interaction and TNF signaling pathway, etc. In the gray module, GO analysis showed that the biological processes were skeletal myofibril assembly related. The immunohistochemistry staining showed that the expression of ASC, Caspase-1 and NLRP3 were increased in GSVs from CABG patients compared with varicose veins. Histopathological analysis showed that in the varicose veins group, the thickness of vascular wall, tunica intima, tunica media and collagen/smooth muscle ratio were significantly increased, and that the elastic fiber/internal elastic lamina ratio was decreased.ConclusionThis study shows that there are clear differences in transcriptomic information between varicose veins and GSVs from CABG patients. Some inflammatory RNAs are down-regulated in varicose veins compared with GSVs from CABG patients. Skeletal myofibril assembly pathway may play a crucial role in the pathogenesis of varicose veins. Characterization of these RNAs may provide new targets for understanding varicose veins diagnosis, progression, and treatment
Thermal Conductivity of Carbon Nanotubes and their Polymer Nanocomposites: A Review
Thermally conductive polymer composites offer new possibilities for replacing metal parts in several applications, including power electronics, electric motors and generators, heat exchangers, etc., thanks to the polymer advantages such as light weight, corrosion resistance and ease of processing. Current interest to improve the thermal conductivity of polymers is focused on the selective addition of nanofillers with high thermal conductivity. Unusually high thermal conductivity makes carbon nanotube (CNT) the best promising candidate material for thermally conductive composites. However, the thermal conductivities of polymer/CNT nanocomposites are relatively low compared with expectations from the intrinsic thermal conductivity of CNTs. The challenge primarily comes from the large interfacial thermal resistance between the CNT and the surrounding polymer matrix, which hinders the transfer of phonon dominating heat conduction in polymer and CNT. This article reviews the status of worldwide research in the thermal conductivity of CNTs and their polymer nanocomposites. The dependence of thermal conductivity of nanotubes on the atomic structure, the tube size, the morphology, the defect and the purification is reviewed. The roles of particle/polymer and particle/particle interfaces on the thermal conductivity of polymer/CNT nanocomposites are discussed in detail, as well as the relationship between the thermal conductivity and the micro- and nano-structure of the composite
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