Real-time Substrate Transport Control for Stable and Efficient Thin-film-based Roll-to-roll (R2R) Micro-nanomanufacturing

The commercialization of electronic devices requires the high efficiency and stable mirco-nanomanufacturing processes that allow frequent design upgrades. R2R Nano is a gateway to science and engineering research that aims to impact the widespread adoption of R2R technologies for low-cost, high-volume production of high technology products on flexible substrates. However, there are lots of the mechanical and chemical factors influencing the system performance when fabricating nano-scale structures. Thus, feedback control system is increasingly playing a great role in improving the R2R performance. The aim of the project is to design a feedback control system for enhancing the performance of the R2R system by harmonizing between the moving speed of substrate, film surface energy and substrate’s tension. In this project, a roll of thin-film with several microns thickness is used as substrate which allows lower process cost and surface quality but also make the substrate transport more challenging than working with much thicker substrate. The control system design mainly consist several subcomponents such as the thin film substrate tension control, nano-patterned liquid dispenser and real-time feedback controller (LabVIEW programming). As a result, the control scheme will allow fabricating uniform nanostructures over a large area at a desired throughput. Based on the improved R2R mechanism, multi-processing can be developed such as imprinting, LWD (laser induced direct-writing) and coating. In the experiment, copper nanoparticles will be used as the substrate to test the performance of the system

Meso-scale Modeling of the Drilling of Carbon Fibre Reinforced Plastic: Geometry and Numerical Analysis

This paper discussed the 3D finite element modeling (FEM) of the drilling of uni-directional Carbon Fibre Reinforced Plastic (CFRP). Most of the real life parts of CFRP are modeled with single layer shell element and can be modeled as composite by assigning a composite property to it. A Meso-Scale (Laminate Level) approach has been developed to extract displacements, overall stiffness behavior, and detailed stresses and strains. The objective of this study is to implement a ply-based modeling technology to model the laminates and to analyze the interaction mechanisms between the drilling tool and material to validate if the meso-scale approach would be the ideal solution to characterize the drilling induced damage. Results show the model has proved its ability to correctly estimate the thrust force and torque

The manufacturing and the application of polycrystalline diamond tools – A comprehensive review

Advanced materials such as titanium alloys and metal matrix composites are extensively used in the aerospace industry and biomedical engineering. They are difficult to machine because of the severe abrasion and high temperature at the tool/chip and tool/workpiece interfaces which cause severe tool wear and premature tool rejection. Compared with conventional cutting tools, polycrystalline diamond (PCD) tools are promising in machining refractory metals and hard-to-machine materials because of the outstanding mechanical properties of PCD. This paper reviewed the manufacturing and application of PCD cutting tools. The researches on manufacturing process of PCD tools and the application in cutting hard-to-machine materials were analysed, and the results and findings were comprehensively discussed. Two most widely used refining methods including abrasive grinding and electrical discharge grinding (EDG) as well as the defects caused by the processes were presented. The wear process of PCD tools in different industrial cutting methods and the wear mechanism of different PCD materials were explained in both micro-scale and macro-scale. Research directions and the trend of the application of PCD cutting tools were introduced

Transcriptional activity regulates alternative cleavage and polyadenylation

Transcriptomic and epigenomic data, as well as reporter and nuclear run-on assays collectively show that transcriptional activity regulates the relative abundance of alternative polyadenylation isoforms, indicating general coupling of 3′ end processing to transcription

Comparative Analysis of mRNA Isoform Expression in Cardiac Hypertrophy and Development Reveals Multiple Post-Transcriptional Regulatory Modules

Cardiac hypertrophy is enlargement of the heart in response to physiological or pathological stimuli, chiefly involving growth of myocytes in size rather than in number. Previous studies have shown that the expression pattern of a group of genes in hypertrophied heart induced by pressure overload resembles that at the embryonic stage of heart development, a phenomenon known as activation of the “fetal gene program”. Here, using a genome-wide approach we systematically defined genes and pathways regulated in short- and long-term cardiac hypertrophy conditions using mice with transverse aortic constriction (TAC), and compared them with those regulated at different stages of embryonic and postnatal development. In addition, exon-level analysis revealed widespread mRNA isoform changes during cardiac hypertrophy resulting from alternative usage of terminal or internal exons, some of which are also developmentally regulated and may be attributable to decreased expression of Fox-1 protein in cardiac hypertrophy. Genes with functions in certain pathways, such as cell adhesion and cell morphology, are more likely to be regulated by alternative splicing. Moreover, we found 3′UTRs of mRNAs were generally shortened through alternative cleavage and polyadenylation in hypertrophy, and microRNA target genes were generally de-repressed, suggesting coordinated mechanisms to increase mRNA stability and protein production during hypertrophy. Taken together, our results comprehensively delineated gene and mRNA isoform regulation events in cardiac hypertrophy and revealed their relations to those in development, and suggested that modulation of mRNA isoform expression plays an importance role in heart remodeling under pressure overload

Methylprednisolone as Adjunct to Endovascular Thrombectomy for Large-Vessel Occlusion Stroke

Importance It is uncertain whether intravenous methylprednisolone improves outcomes for patients with acute ischemic stroke due to large-vessel occlusion (LVO) undergoing endovascular thrombectomy. Objective To assess the efficacy and adverse events of adjunctive intravenous low-dose methylprednisolone to endovascular thrombectomy for acute ischemic stroke secondary to LVO. Design, Setting, and Participants This investigator-initiated, randomized, double-blind, placebo-controlled trial was implemented at 82 hospitals in China, enrolling 1680 patients with stroke and proximal intracranial LVO presenting within 24 hours of time last known to be well. Recruitment took place between February 9, 2022, and June 30, 2023, with a final follow-up on September 30, 2023.InterventionsEligible patients were randomly assigned to intravenous methylprednisolone (n = 839) at 2 mg/kg/d or placebo (n = 841) for 3 days adjunctive to endovascular thrombectomy. Main Outcomes and Measures The primary efficacy outcome was disability level at 90 days as measured by the overall distribution of the modified Rankin Scale scores (range, 0 [no symptoms] to 6 [death]). The primary safety outcomes included mortality at 90 days and the incidence of symptomatic intracranial hemorrhage within 48 hours. Results Among 1680 patients randomized (median age, 69 years; 727 female [43.3%]), 1673 (99.6%) completed the trial. The median 90-day modified Rankin Scale score was 3 (IQR, 1-5) in the methylprednisolone group vs 3 (IQR, 1-6) in the placebo group (adjusted generalized odds ratio for a lower level of disability, 1.10 [95% CI, 0.96-1.25]; P = .17). In the methylprednisolone group, there was a lower mortality rate (23.2% vs 28.5%; adjusted risk ratio, 0.84 [95% CI, 0.71-0.98]; P = .03) and a lower rate of symptomatic intracranial hemorrhage (8.6% vs 11.7%; adjusted risk ratio, 0.74 [95% CI, 0.55-0.99]; P = .04) compared with placebo. Conclusions and Relevance Among patients with acute ischemic stroke due to LVO undergoing endovascular thrombectomy, adjunctive methylprednisolone added to endovascular thrombectomy did not significantly improve the degree of overall disability.Trial RegistrationChiCTR.org.cn Identifier: ChiCTR210005172

Effects of cooling conditions on surface properties of heated coals

Cooling coal mines to prevent spontaneous combustion is usually considered to be one important method to prevent coal combustion. Cooling methods may be divided into two main types, a water cooling method and an isolate cooling method (under a vacuum condition). This investigation is to find out the effects of cooling conditions on surface properties of heated coals. Heated coals were cooled in a vacuum chamber and cooled in water. X-ray photoelectron spectroscopy, scanning electron microscope, and contact angle measurements were used to indicate surface properties of heated coals under different cooling conditions. The results showed that heated coal cooled in water (Coal2) was more hydrophilic than heated coal cooled in a vacuum chamber (Coal1). Coal2 could be oxidized more than Coal1. This paper gives an opinion that cooling heated coals in spontaneous combustion using an isolate cooling method (under a vacuum condition) is useful for the flotation upgrade of fine coals, because the flotation upgrade of fine coals is based on the hydrophobicity of the coal surface. However, cooling heated coals in water reduces this hydrophobicity because an oxidation process can occur on a heated coal surface in water

Comparison of traditional and zero-conditioning flotation performances of oxidized anthracite coal

Oxidized coal is usually difficult to float using common oily collectors in a traditional flotation process. In order to float oxidized coal efficiently, this paper proposed a novel flotation process which was named zero-conditioning flotation process. Samples of oxidized anthracite coal were used in flotation tests throughout the paper. Fourier transform infrared spectroscopy (FTIR) was used to indicate the chemical properties of coal samples. A comparison of traditional and zero-conditioning flotation performances of oxidized anthracite coal was investigated. It was found that the zero-conditioning flotation process was suitable for the upgrading of oxidized anthracite coal. Combustible matter recovery in the zero-conditioning flotation process was much higher than that in the traditional flotation process. In addition, concentrate ash content in the zero-conditioning flotation process was a little lower than that in the traditional flotation process