Nanoscale properties of conjugated polymers by scanning probe microscopy

Nanoscale properties of conjugated polymers by Scanning Probe Microscopy Atomic force microscopy (AFM) and electrostatic force microscopy (EFM) are explored and developed to study the surface potential distribution for a range of applications, including semiconductor laser devices, the electrical conductivity of aligned DNA molecules. The main focus of the thesis is the application of these techniques to investigate the nanoscale structures and electrical properties of conjugated polymers, including poly-(3-exylthiophene)s (P3ATs), polyfluorene (PFO), and poly-(3,4,-ethylenedioxythiophene) (PEDOT). EFM is a SPM technique, used to measure electrostatic force in non-contact mode. Two modes of EFM, scanning Kelvin probe microscopy (KPM or SKPM) and EFM/phase, are explored. Analytical calculations of tip-surface capacitances and their gradients are presented, aiming at quantifying the measurement. Based on the calculation results, the origin of the measurement resolution in EFM/phase and SKPM is explained, and a procedure is developed to convert the phase shift to the local surface potential. Thus, EFM/phase can also be used to measure the surface potential with higher resolution than SKPM. The self-assembled/aggregation structures of the polymers, as varied by molecular weight, solution preparation and substrates used, are investigated by AFM. The self-assembled structure, usually in the form of a network, obeys certain laws in its formation. The surface potential distributions and charge transport properties in polymer films and network structures are investigated with both EFM modes. The electrical properties of Au on poly-(3-hexylthiophene) (P3HT) and P3HT on Au contacts are investigated. The electrochemical reaction of conjugated polymers, and electropolymerisation of 3,4-ethylenedioxythiophene (EDOT) are carried out on micro electrodes, and studied by AFM. The EDOT electropolymerization is shown to grow polymer nano-wires or a uniform polymer film, depending on conditions the electropolymerization process.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Nanoscale properties of conjugated polymers by scanning probe microscopy

Nanoscale properties of conjugated polymers by Scanning Probe Microscopy Atomic force microscopy (AFM) and electrostatic force microscopy (EFM) are explored and developed to study the surface potential distribution for a range of applications, including semiconductor laser devices, the electrical conductivity of aligned DNA molecules. The main focus of the thesis is the application of these techniques to investigate the nanoscale structures and electrical properties of conjugated polymers, including poly-(3-exylthiophene)s (P3ATs), polyfluorene (PFO), and poly-(3,4,-ethylenedioxythiophene) (PEDOT). EFM is a SPM technique, used to measure electrostatic force in non-contact mode. Two modes of EFM, scanning Kelvin probe microscopy (KPM or SKPM) and EFM/phase, are explored. Analytical calculations of tip-surface capacitances and their gradients are presented, aiming at quantifying the measurement. Based on the calculation results, the origin of the measurement resolution in EFM/phase and SKPM is explained, and a procedure is developed to convert the phase shift to the local surface potential. Thus, EFM/phase can also be used to measure the surface potential with higher resolution than SKPM. The self-assembled/aggregation structures of the polymers, as varied by molecular weight, solution preparation and substrates used, are investigated by AFM. The self-assembled structure, usually in the form of a network, obeys certain laws in its formation. The surface potential distributions and charge transport properties in polymer films and network structures are investigated with both EFM modes. The electrical properties of Au on poly-(3-hexylthiophene) (P3HT) and P3HT on Au contacts are investigated. The electrochemical reaction of conjugated polymers, and electropolymerisation of 3,4-ethylenedioxythiophene (EDOT) are carried out on micro electrodes, and studied by AFM. The EDOT electropolymerization is shown to grow polymer nano-wires or a uniform polymer film, depending on conditions the electropolymerization process

Solution-processed bilayer photovoltaic devices with nematic liquid crystals

The cross-linking of polymerisable liquid crystalline semiconductors is a promising approach to solution-processable, multilayer, organic photovoltaics. Here we demonstrate an organic bilayer photovoltaic with an insoluble electron-donating layer formed by cross-linking a nematic reactive mesogen. We investigate a range of perylene diimide (PDI) materials, some of which are liquid crystalline, as the overlying electron acceptor layer. We find that carrier mobility of the acceptor materials is enhanced by liquid crystallinity and that mobility limits the performance of photovoltaic devices. © 2013 © 2013 Taylor & Francis

Separation of nickel from cobalt and manganese in lithium ion batteries using deep eutectic solvents

The authors would like to thank the Faraday Institution (grant codes FIRG005 and FIRG006) for funding (Project website https://relib.org.uk). This research also received funding from the European Commission's H2020 – Marie Sklodowska Curie Actions (MSCA) − Innovative Training Networks within the SOCRATES project under the grant agreement no. 721385 (Project website: https://etn-socrates.eu).A cornerstone of the decarbonisation agenda is the use of lithium ion batteries, particularly for electric vehicles. It is essential that effective recycling protocols are developed and this includes the ability to selectively digest and recover components of the cathode materials, most commonly including manganese, cobalt and nickel. This study shows a method by which nickel oxide can be efficiently separated from cobalt and manganese oxides using an oxalic acid-based deep eutectic solvent. The subsequent addition of water to the pregnant solution enables the co-precipitation of cobalt and manganese oxalates. This permits a route to the reformulation of the active materials from high cobalt and manganese content to high nickel content.Publisher PDFPeer reviewe

Association between increased C-reactive protein and cardiovascular disease among patients with rectal cancer

PurposeThis study aimed to investigate the association between increased C-reactive protein (CRP) and cardiovascular disease (CVD) in individuals with rectal cancer, as well as to understand the effect of chemotherapy for cancer on increasing CRP and its underlying mechanisms.Patients and methodsFrom January 1, 2010 to December 31, 2020, individuals with rectal cancer were evaluated at the First Affiliated Hospital of Gannan Medical University. Then, in patients with rectal cancer, the relationship between increased CRP and CVD attributes was summarized, and the impact of chemotherapy on CRP levels was qualitatively assessed. For further investigation into potential regulatory mechanisms of CRP, differentially expressed genes (DEGs), GO and KEGG enrichment analyses were conducted.ResultsA total of 827 individuals were included in the study, including 175 with CVD (21.16%) and 652 without CVD. A significant association between increased CRP and CVD events was observed in rectal cancer patients (p < 0.01), and it significantly improved the classification performance of the CVD predictive model in the AUC (0.724 vs 0.707) and NRI (0.069, 95% CI 0.05-0.14). Furthermore, a comparison of CRP levels before and after chemotherapy revealed a significant increase among rectal cancers post-treatment (p < 0.001). Analysis of differentially expressed genes and co-expression indicated that 96 DEGs were involved in the pathophysiology of increased CRP after chemotherapy, and three hub genes were implicated in atherosclerotic susceptibility.ConclusionIn conclusion, our findings indicated that increased CRP levels following chemotherapy profoundly impacted CVD events in individuals with rectal cancer, and may be beneficial in promoting CVD prediction in clinical practice

Mesangial cell: A hub in lupus nephritis

Lupus nephritis (LN) is a severe renal disease caused by the massive deposition of the immune complexes (ICs) in renal tissue, acting as one of the significant organ manifestations of systemic lupus erythematosus (SLE) and a substantial cause of death in clinical patients. As mesangium is one of the primary sites for IC deposition, mesangial cells (MCs) constantly undergo severe damage, resulting in excessive proliferation and increased extracellular matrix (ECM) production. In addition to playing a role in organizational structure, MCs are closely related to in situ immunomodulation by phagocytosis, antigen-presenting function, and inflammatory effects, aberrantly participating in the tissue-resident immune responses and leading to immune-mediated renal lesions. Notably, such renal-resident immune responses drive a second wave of MC damage, accelerating the development of LN. This review summarized the damage mechanisms and the in situ immune regulation of MCs in LN, facilitating the current drug research for exploring clinical treatment strategies

Case report: Fatal Legionella infection diagnosed via by metagenomic next-generation sequencing in a patient with chronic myeloid leukemia

Legionella is an aerobic, gram-negative, intracellular pathogen and is an important cause of community-acquired pneumonia. Legionella pneumophila is the most common causative agent of Legionella pneumonia. Clinical diagnosis of Legionella pneumonia is challenging due to the lack of specific clinical manifestations and the low positive rates of conventional pathogen detection methods. In this study, we report a case of a patient with chronic myeloid leukemia who developed rigors and high fever after chemotherapy and immunotherapy. Chest computed tomography revealed consolidation in the left lower lobe of the lung and ground-glass opacities in both lower lobes. Multiple blood cultures showed Escherichia coli, Staphylococcus aureus, Bacillus licheniformis, and positive results in the β-D-glucan test (G test). The patient was treated with various sensitive antimicrobial agents, including meropenem plus fluconazole, meropenem plus carpofungin, and vancomycin. Unfortunately, the patient’s condition gradually worsened and eventually resulted in death. On the following day of death, metagenomic next-generation sequencing (mNGS) of 1whole blood revealed L. pneumophila pneumonia with concurrent bloodstream infection (blood mNGS reads 114,302). These findings suggest that when conventional empirical antimicrobial therapy proves ineffective for critically ill patients with pneumonia, the possibility of combined Legionella infection must be considered, and mNGS can provide a diagnostic tool in such cases

Analysis of tall fescue ESTs representing different abiotic stresses, tissue types and developmental stages

<p>Abstract</p> <p>Background</p> <p>Tall fescue (<it>Festuca arundinacea </it>Schreb) is a major cool season forage and turf grass species grown in the temperate regions of the world. In this paper we report the generation of a tall fescue expressed sequence tag (EST) database developed from nine cDNA libraries representing tissues from different plant organs, developmental stages, and abiotic stress factors. The results of inter-library and library-specific <it>in silico </it>expression analyses of these ESTs are also reported.</p> <p>Results</p> <p>A total of 41,516 ESTs were generated from nine cDNA libraries of tall fescue representing tissues from different plant organs, developmental stages, and abiotic stress conditions. The <it>Festuca </it>Gene Index (FaGI) has been established. To date, this represents the first publicly available tall fescue EST database. <it>In silico </it>gene expression studies using these ESTs were performed to understand stress responses in tall fescue. A large number of ESTs of known stress response gene were identified from stressed tissue libraries. These ESTs represent gene homologues of heat-shock and oxidative stress proteins, and various transcription factor protein families. Highly expressed ESTs representing genes of unknown functions were also identified in the stressed tissue libraries.</p> <p>Conclusion</p> <p>FaGI provides a useful resource for genomics studies of tall fescue and other closely related forage and turf grass species. Comparative genomic analyses between tall fescue and other grass species, including ryegrasses (<it>Lolium </it>sp.), meadow fescue (<it>F. pratensis</it>) and tetraploid fescue (<it>F. arundinacea var glaucescens</it>) will benefit from this database. These ESTs are an excellent resource for the development of simple sequence repeat (SSR) and single nucleotide polymorphism (SNP) PCR-based molecular markers.</p