ROMI: design and experimental evaluation of a linear delta robotic system for high-precision applications

In this paper, the design and experimental evaluation of a parallel robotic system based on a linear delta geometry is presented. The design considers the requirements for high-precision applications including workspace, motion resolution, and payload. The entire design process includes robot kinematics, control, and optimization, resulting in the demonstration of a working device. The robot structure offers a versatile and simplified design when compared with state-of-the-art devices being able to be adapted to perform different tasks while keeping the advantages of high precision with reduced complexity. The presented robot prototype was constructed and evaluated experimentally through three proof-of-concept experiments mimicking tasks requiring high motion precision such as microsurgery, semiconductor testing, and optical device alignment. The obtained results in the three experimental scenarios validate that the here-proposed design can achieve an average motion precision of ~3.3 ± 0.3 μm with varying load conditions, thus confirming its potential to be used for high-precision tasks in industrial and medical settings.</p

Soluble Perfluorocyclobutyl Aryl Ether-Based Polyimide for High-Performance Dielectric Material

High durability of low-<i>k</i> value is a desired property for dielectrics serving under humid conditions, because absorbing a small amount of moisture by the material can considerably increase the <i>k</i> value so as to result in function deterioration. Aiming to develop a dielectric polymer with superior durability of low-<i>k</i> value and high thermal stability, a perfluorocyclobutyl (PFCB) biphenyl ether-based polyimide, PFCBBPPI, was synthesized. This polymer possesses a <i>T</i>_g of 310.3 °C and a 5% weight loss temperature of 510.5 °C. PFCBBBPPI exhibited an extremely low water uptake of 0.065 ± 0.018%, representing the best water resistance in polyimides. The increasing percentage in <i>k</i> value was below 2% for PFCBBPPI film exposed to moisture under various humidity conditions for 6 h. PFCBBPPI film equilibrated at 75% R.H. for 2 weeks still kept its <i>k</i> value below 2.50, remarkably outperforming the Kapton film. The remarkable water resistance and resulting high durability of low-<i>k</i> property displayed by PFCBBPPI are originated from the hydrophobic nature and small free volume fraction of the polymer, as confirmed by contact angle test and positron annihilation lifetime spectroscopy results. The outstanding moisture resistance and overall performance of PFCBBPPI make it a suitable candidate for dielectric applications under both dry and humid conditions

Stability and Catalytic Activity of PEG‑<i>b</i>‑PS-Capped Gold Nanoparticles: A Matter of PS Chain Length

Gold nanoparticles (AuNPs) covered with a series of well-defined poly­(ethylene glycol)-<i>b</i>-polystyrene (PEG-<i>b</i>-PS) amphiphilic diblock copolymers containing a thiol group at the end of PS block were prepared to explore the influence of chain length of PS segment on the colloidal stability and catalytic activity of AuNPs. PEG-<i>b</i>-PS amphiphilic diblock copolymers with different PS chain lengths and narrow molecular distributions (<i>M</i>_w/<i>M</i>_n ≤ 1.15) were synthesized by reversible addition–fragmentation chain transfer (RAFT) polymerization employing a PEG-based macromolecular chain transfer agent (<i>M</i>_n ≈ 2000 g/mol), followed by transforming the thiocarbonate end functionality into a thiol group in the presence of 2-aminoethanol and tributylphosphane. PEG-<i>b</i>-PS-stabilized gold nanoparticles (Au@PEG-<i>b</i>-PS) were prepared by ligand exchange reaction between citrate-stabilized AuNPs and the thiol end group of PEG-<i>b</i>-PS diblock copolymer. The presence of the hydrophobic PS layer not only improved the stability of Au@PEG-<i>b</i>-PS against electrolyte-induced aggregation but also greatly promoted the resistance of Au@PEG-<i>b</i>-PS against competitive displacement of dithiothreitol. Au@PEG-<i>b</i>-PS showed excellent catalytic activity in the reduction reaction of 4-nitrophenol into 4-aminophenol, and the catalytic activity increased with the decrease in the chain length of PS block. In addition, the high stability imparted by the PS layer endowed Au@PEG-<i>b</i>-PS with good reusability in catalysis without the loss of catalytic activity

Self-Assembly of Amphiphilic Homopolymers Bearing Ferrocene and Carboxyl Functionalities: Effect of Polymer Concentration, β‑Cyclodextrin, and Length of Alkyl Linker

Three new acrylamide monomers containing ferrocene and <i>tert</i>-butyl ester groups were first synthesized via multistep nucleophilic substitution reaction under mild conditions followed by reversible addition–fragmentation chain transfer (RAFT) homopolymerization to give well-defined homopolymers with narrow molecular weight distributions (<i>M</i>_w/<i>M</i>_n ≤ 1.36). The target amphiphilic homopolymers were obtained by the acidic hydrolysis of <i>tert</i>-butyoxycarbonyls to carboxyls in every repeating unit using CF₃COOH. The self-assembly behaviors of these amphiphilic homopolymers bearing both ferrocene and carboxyl moieties in each repeating unit in aqueous media were investigated by transmission emission microscopy (TEM), dynamic light scattering (DLS), and atomic force microscopy (AFM). Large compound micelles with different morphologies were formed by these amphiphilic homopolymers, which consist of the corona formed by hydrophilic carboxyls and the core containing numerous reverse micelles with hydrophilic islands of carboxyls in continuous hydrophobic phase of ferrocene-based segments. The morphologies of the formed micelles could be tuned by the concentration of amphiphilic homopolymers, pH value of the solution, the length of −CH₂ linker between ferrocene group and carboxyl, and the amount of β-cyclodextrin (β-CD)

Covalently Functionalized Graphene by Radical Polymers for Graphene-Based High-Performance Cathode Materials

Polymer-functionalized graphene sheets play an important role in graphene-containing composite materials. Herein, functionalized graphene sheets covalently linked with radical polymer, graphene-<i>graft</i>-poly­(2,2,6,6-tetramethylpiperidin-1-oxyl-4-yl methacrylate) (G-<i>g</i>-PTMA), were prepared via surface-initiated atom transfer radical polymerization (SI-ATRP). A composite cathode with G-<i>g</i>-PTMA as major active material and reduced graphene oxide (RGO) as conductive additive was fabricated via a simple dispersing–depositing process, and this composite cathode exhibited a relatively high specific capacity up to 466 mAh g^–1 based on the mass of PTMA, which is much higher than the theoretical capacity of PTMA. This extraordinary electrochemical performance is attributed to the fast one-electron redox reaction of G-<i>g</i>-PTMA and surface Faradaic reaction of RGO boosted by G-<i>g</i>-PTMA, which suggested that G-<i>g</i>-PTMA sheets play a dual role in the composite materials, that is, on the one hand provided the fast one-electron redox reaction of PTMA and on the other hand worked as nanofiller for facilitating the surface Faradaic reaction-based lithium storage of RGO

One-Step Preparation of Fluorographene: A Highly Efficient, Low-Cost, and Large-Scale Approach of Exfoliating Fluorographite

Fluorographene, a cousin of graphene, not only inherits the excellent mechanical properties of graphene but also has great unique application potential in high-performance devices and materials, such as lubricating agents, digital transistors, nanocomposites, and energy-storage devices. However, large-scale preparation of fluorographene remains a great challenge. Herein, an easy-operating, highly scalable, and low-cost approach was reported for the preparation of fluorographene using commercially available fluorographite as the starting material. In this procedure, fluorographite turned into few-layer fluorographene through a rapid exfoliation process with Na₂O₂ and HSO₃Cl as exfoliating agents. The whole preparation process was performed in air and without heating, sonication, and protective gas. The obtained fluorographene was characterized by Fourier transform infrared spectroscopy, Raman spectroscopy, ¹⁹F nuclear magnetic resonance spectroscopy, X-ray diffraction, thermogravimetric analysis, atomic force microscopy, and transmission electron microscopy, and it possesses a hexagonal polycrystalline structure. Fluorographene and fluorographite were employed as cathode materials of the primary lithium battery, and it was found that the specific discharge capacity of the battery using fluorographene was improved remarkably compared to that using fluorographite. Cyclic voltammetry results also showed that specific capacitances of fluorographene were dozens of times higher than that of fluorographite. It is clear that electrochemical properties of fluorographene are significantly improved against fluorographite

Investigation of Exciton Recombination Zone in Quantum Dot Light-Emitting Diodes Using a Fluorescent Probe

Exciton recombination zone, where the photons are generated, can greatly affect the performance, such as the efficiency and color purity, of the quantum dot (QD) light-emitting diodes (QLEDs). To probe the exciton recombination zone, 4-(dicyanomethylene)-2-<i>t</i>-butyl-6­(1,1,7,7-tetramethyljulolidyl-9-enyl)-4<i>H</i>-pyran (DCJTB) is doped into the charge transport layer as a fluorescent sensor; by monitoring the Förster resonant energy transfer (FRET) between QD and DCJTB, the location of the recombination zone can be determined. It is found that the electron transport layer (ETL) has a great impact on the recombination zone. For example, in QLEDs with ZnMgO ETL, the recombination zone is near the interface of the QD/hole transport layer (HTL) and is shifted to the interface of the QD/ETL as the driving voltage is increased, whereas in devices with 1,3,5-tris­(2-<i>N</i>-phenylbenzimidazolyl) benzene (TPBi) ETL, the recombination zone is close to the interface of the QD/ETL and moved to the interface of the QD/HTL with the increase in the driving voltage. Our results can also clarify the light emission mechanism in QLEDs. In devices with ZnMgO ETL, the emission is dominated by the direct charge recombination, whereas in devices with TPBi ETL, the emission is contributed by both FRET and direct charge recombination. Our studies suggest that fluorescent probe can be a powerful tool for investigating the exciton recombination zone, light emission mechanism, and other fundamental processes in QLEDs

DataSheet1_High expression of B4GALT1 is associated with poor prognosis in acute myeloid leukemia.docx

Acute myeloid leukemia is the most prevalent type of leukemia in adults and is prone to relapse and chemoresistance, with a low long-term survival rate. Therefore, the identification of quality biomarkers constitutes an urgent unmet need. High expression of beta-1,4-galactosyltransferase 1 (B4GALT1) has been observed in several cancer types; however, its function in acute myeloid leukemia has rarely been studied. Therefore, our study obtained gene expression data from The Cancer Genome Atlas (TCGA) database to analyze the relationship between B4GALT1 and LAML. We compared the expression of B4GALT1 in LAML and healthy samples using the Wilcoxon rank-sum test. Furthermore, the association between B4GALT1 and survival rates was investigated using Kaplan-Meier analysis and Cox regression. The nomogram obtained by Cox analysis predicts the effect of B4GALT1 on the prognosis. To assess B4GALT1-related genes’ enrichment pathway and function and the correlation between B4GALT1 and immune features, GO/KEGG, protein-protein interaction network, and single sample gene set enrichment analysis were used. In addition, B4GALT1-specific siRNAs were used to verify the effect of B4GALT1 on apoptosis. The results showed that B4GALT1 is overexpressed in LAML and has some reference value in the diagnostic and prognostic assessment of LAML. Moreover, functional enrichment showed that B4GALT1 and its 63 associated genes were closely associated with the negative regulation of the apoptotic signaling pathway. Silencing B4GALT1 significantly promoted apoptosis. In addition, B4GALT1 expression was positively correlated with the infiltration levels of macrophages, regulatory T-cell (Tregs), and Th17 cells; in contrast, B4GALT1 expression was negatively correlated with the infiltration levels of T helper cells, Mast cells, and NK cells. In conclusion, our study shows that B4GALT1 may play a vital role in the occurrence of LAML.</p

Image_6_Transcriptomics yields valuable information regarding the response mechanisms of Chinese Min pigs infected with PEDV.pdf

Porcine epidemic diarrhea virus (PEDV) causes porcine epidemic diarrhea (PED), a highly infectious disease, which has resulted in huge economic losses for the pig industry. To date, the pathogenic and immune response mechanism was not particularly clear. The purpose of this study was to investigate the pathogenic and immune responses of pigs infected with PEDV.In this study, 12 Min pigs were randomly selected without taking colostrum. At 3 days old, eight piglets were infected with 1 mL of PEDV solution (10 TCID50/ml), and the remaining four piglets were handled by 1 mL of 0.9% normal saline. Within the age of 7 days old, four piglets died and were considered as the death group. Correspondingly, four alive individuals were classified into the resistance group. Tissues of the duodenum, jejunum, ileum, colon, cecum, and rectum of piglets in the three groups were collected to measure the PEDV content. Additionally, the jejunum was used for the measurements and analyses of Hematoxylin-eosinstaining (HE), immunohistochemical sections, and transcriptomics. The phenotypes of Min piglets infected with PEDV showed that the viral copy numbers and jejunal damage had significant differences between the death and resistance groups. We also observed the transcriptome of the jejunum, and the differentially expressed (DE) analysis observed 6,585 DE protein-coding genes (PCGs), 3,188 DE long non-coding RNAs (lncRNAs), and 350 DE microRNAs (miRNAs), which were mainly involved in immune response and metabolic pathways. Furthermore, the specific expressed molecules for each group were identified, and 97 PCGs,108 lncRNAs, and 51 miRNAs were included in the ceRNA-regulated networks. By weighted gene co-expression network analysis (WGCNA) and transcription factor (TF) prediction, 27 significant modules and 32 significant motifs (E-value < 0.05) annotated with 519 TFs were detected. Of these TFs, 53 were DE PCGs. In summary, the promising key PCGs, lncRNAs, and miRNAs related to the pathogenic and immunological response of pigs infected with PEDV were detected and provided new insights into the pathogenesis of PEDV.</p