Polyviologens: Electrochemical Synthesis and Characterization

Microelectronics and flexible electronics are applications that have attracted more and more attention in the today’s world. The research of these kinds of electronics requires the development and improvement of existing functional materials. The viologen is one of the most frequently utilized functional materials in many different applications. Due to its unique redox property and variety of colors, the viologen materials have got worldwide attention in different fields of research. In this work, several crosslinked polyviologen and copolyviologen film were synthesized electrochemically from different cyanopyridine based precursors. Additionally, the polyviologen based composite film was also synthesized with the introduction of graphene oxide. All of these polyviologen materials were characterized with several electrochemical, physicochemical and imaging techniques, such as cyclic voltammetry, electrochemical impendence spectroscopy, in-situ UV-vis spectroscopy, FTIR and Raman spectroscopy, Atomic Force Microscopy, Scanning Electron Microscopy and the contact angle technique, just to mention the most used techniques. All of the synthesized polyviologen materials showed good redox properties and unique structures, so they possess great possibility to be applied in several different fields of applications. Due to their stable redox properties and unique porous structures, the polyviologen films have shown huge potential in the applications, both as functional materials and immobilization material, properties advantageous in varies electronics where minimization and flexibility are important parameters to achieve. By introduction of graphene oxide, the electrochemical properties of polyviologen-reduced graphene oxide based composite films could be improved making the composite structures an interesting material candidate when thinking about energy storage devices. All of these results indicate that polyviologen materials can work as multifunctional material in future applications.Nykyisin mikroelektroniikka ja taipuisa elektroniikka ovat saaneet yhä enemmän huomiota osakseen. Tällaisen elektroniikan tutkimus vaatii uudenlaisten ja parempien funktionaalisten materiaalien kehittämistä. Viologeeni on yksi yleisimmin käytetty funktionaalinen materiaali monissa eri sovelluksissa. Erilaisten viologeenimateriaalien yksilölliset hapetus-pelkistysominaisuudet ja kyky tuottaa erilaisia värejä ovat saaneet huomiota maailmanlaajuisesti monen eri alan tutkimuksessa. Polyviologeeni-materiaaleja on tutkittu pyrittäessä hyödyntämään viologeenijohdannaisia erilaisissa elektroniikan sovelluksissa. Tässä työssä syntetisoitiin sähkökemiallisesti useita ristisilloitettuja polyviologeeni ja kopolyviologeenikalvoja erilaisista syanopyridiini-pohjaisista esiasteista. Lisäksi polyviologeenipohjaisia komposiittikalvoja syntetisoitiin yhdessä grafeenioksidin kanssa. Kaikki nämä polyviologeenimateriaalit karakterisoitiin useilla sähkö-kemiallisilla, fysikaaliskemiallisilla ja kuvantamistekniikoilla, kuten syklisellä voltammetrialla, sähkökemiallisella impedanssispektroskopialla, in-situ UV-vis-spektroskopialla, FTIR-spektroskopialla, Ramanspektroskopialla, atomivoimamikroskopialla, pyyhkäisyelektronimikroskopialla sekä kontaktikulmamittauksin ja niin edelleen. Kaikilla syntetisoiduilla polyviologeenimateriaaleilla on hyvät hapetus-pelkistys-ominaisuudet ja yksilölliset rakenteet, mikä mahdollistaa niiden käytön usealla eri sovellusalueella. Johtuen polyviologeenien stabiileista hapetus-pelkistysominaisuuksista ja luonteenomaisesta huokoisesta rakenteesta, niistä valmistetuilla kalvoilla on paljon sovellusmahdollisuuksia funktionaalisina materiaaleina sellaisenaan tai immobilisaatiomateriaaleina muille kalvon komponenteille. Tällaisia kalvoja voidaan käyttää laajasti elektroniikassa rakenteiden minimoimiseen ja taipuisien rakenteiden valmistukseen. Käyttämällä polyviologeenin komposiittikalvoissa pelkistettyä grafeenioksidia, pystytään kalvon sähkökemiallisia ominaisuuksia parantamaan, mikä on erinomainen ominaisuus sovellettaessa komposiitteja energian varastoinnissa käytettäviin laitteisiin. Kaikki tulokset osoittavat, että polyviologeenit voivat toimia monipuolisina funktionaalisina materiaaleina tulevaisuudessa.Siirretty Doriast

Combining Intellectual Alignment and Social Alignment to Achieve Agility: Polynomial Regression and Response Surface Analysis

One of the difficulties and hotspots in the current information system (IS) research is determining how to combine the different dimensions of information technology (IT) alignment to better achieve agility under the condition of limited resources. To address this challenge, this study decomposes IT alignment into intellectual and social dimensions and examines the effects of balance and imbalance between them on agility in dynamic environments. Based on survey data from 245 dyads of business and IT executives, we apply polynomial regression and response surface analysis to assess these effects. Results indicate that a firm achieves more agility when intellectual alignment and social alignment are balanced and at high levels, and social alignment is higher than intellectual alignment. Furthermore, the relationship between agility and the balance of intellectual alignment and social alignment will be negatively moderated by environmental dynamism, and the relationship between agility and the combination of low intellectual alignment and high social alignment will be positively moderated by environmental dynamism

Breakage and separation mechanism of ZGM coal mill based on parameters optimization model

Sampling ports were firstly drilled on a ZGM95 coal mill in the power plant in China, and the coal samples from various points in the pulverizer were collected under the different operation conditions. The property of the sampling material from the mill was analyzed, applying the float-sink test, size distribution analysis, proximate analysis and so on. It was indicated that the +250 μm fraction in the pulverized fuel accounted for only 0.02%, while it was 83.2% in the new feed. The circulating ratio and coal flow in the separator and the cone zone were calculated using the mass balance of the circulating load. So, the circulating ratio in the separator of the pulverizer was between 8 and 13, and the circulating ratio, the feed flow of separator and cone zone all raised with the increase of the air volume. Furthermore, the parameters of the separation functions were obtained based on the fitting method. It was shown that the mean value of the shape factor B was 0.7617, and the parameter D which is the particle size at 50% cumulative yield in the separator almost kept unchanged

Research on crushing mechanism and separation characteristic of ZGM coal mill

The holes of ZGM95 coal mill in coal-fired power plants have been firstly drilled in China to collect the coal samples from various points in the separator under the different operation condition. The material property is analyzed by the float-sink test and the sample size distribution. The circulating rate and material flux of the separator and cone zone are calculated by the mass balance models of circulating load. Moreover, the influence rules of the mill coal feed, air quantity, hydraulic loading force and coal property on the circulating rate and internal material distribution are discussed by the quantity and quality balance. The circulating rate and input material flux of the separator and cone zone all increase with the mill air quantity

Simultaneous Visualization of MiRNA-221 and Caspase-3 in Cancer Cells for Investigating the Feasibility of MiRNA-Targeted Therapy with a Dual-Color Fluorescent Nanosensor

MiRNA-targeted therapy holds great promise for precision cancer therapy. It is important to investigate the effect of changes in miRNA expression on apoptosis in order to evaluate miRNA-targeted therapy and achieve personalized therapy. In this study, we designed a dual-color fluorescent nanosensor consisting of grapheme oxide modified with a molecular beacon and peptide. The nanosensor can simultaneously detect and image miRNA-221 and apoptotic protein caspase-3 in living cells. Intracellular experiments showed that the nanosensor could be successfully applied for in situ monitoring of the effect of miRNA-221 expression changes on apoptosis by dual-color imaging. The current strategy could provide new avenues for investigating the feasibility of miRNA-targeted therapy, screening new anti-cancer drugs targeting miRNA and developing personalized treatment plans

Visualizing MiRNA Regulation of Apoptosis for Investigating the Feasibility of MiRNA-Targeted Therapy Using a Fluorescent Nanoprobe

MiRNA-targeted therapy is an active research field in precision cancer therapy. Studying the effect of miRNA expression changes on apoptosis is important for evaluating miRNA-targeted therapy and realizing personalized precision therapy for cancer patients. Here, a new fluorescent nanoprobe was designed for the simultaneous imaging of miRNA-21 and apoptotic protein caspase-3 in cancer cells by using gold nanoparticles as the core and polydopamine as the shell. Confocal imaging indicated that the nanoprobe could be successfully applied for in situ monitoring of miRNA regulation of apoptosis. This design strategy is critical for investigating the feasibility of miRNA-targeted therapy, screening new anti-cancer drugs targeting miRNA, and developing personalized treatment plans

Redox-Enhanced Photoelectrochemical Activity in PHV/CdS Hybrid Film

Semiconductive photocatalytic materials have received increasing attention recently due to their ability to transform solar energy into chemical fuels and photodegrade a wide range of pollutants. Among them, cadmium sulfide (CdS) nanoparticles have been extensively studied as semiconductive photocatalysts in previous studies on hydrogen generation and environmental purification due to their suitable bandgap and sensitive light response. However, the practical applications of CdS are limited by its low charge separation, which is caused by its weak ability to separate photo-generated electron-hole pairs. In order to enhance the photoelectrochemical activity of CdS, a polymer based on viologen (PHV) was utilized to create a series of PHV/CdS hybrid films so that the viologen unit could work as the electron acceptor to increase the charge separation. In this work, various electrochemical, spectroscopic, and microscopic methods were utilized to analyze the hybrid films, and the results indicated that introducing PHV can significantly improve the performance of CdS. The photoelectrochemical activities of the hybrid films were also evaluated at various ratios, and it was discovered that a PHV-to-CdS ratio of 2:1 was the ideal ratio for the hybrid films. In comparison with CdS nanoparticles, the PHV/CdS hybrid film has a relatively lower band gap, and it can inhibit the recombination of electrons and holes, enhancing its photoelectrochemical activities. All of these merits make the PHV/CdS hybrid film as a strong candidate for photocatalysis applications in the future

Physically Crosslinked Chitosan/PVA Hydrogels Containing Honey and Allantoin with Long-Term Biocompatibility for Skin Wound Repair: An In Vitro and In Vivo Study

Chitosan/PVA hydrogel films crosslinked by the freeze–thaw method and containing honey and allantoin were prepared for application as wound dressing materials. The effects of the freeze–thaw process and the addition of honey and allantoin on the swelling, the gel content and the mechanical properties of the samples were evaluated. The physicochemical properties of the samples, with and without the freeze–thaw process, were compared using FTIR, DSC and XRD. The results showed that the freeze–thaw process can increase the crystallinity and thermal stability of chitosan/PVA films. The freeze–thaw process increased the gel content but did not have a significant effect on the tensile strength. The presence of honey reduced the swelling and the tensile strength of the hydrogels due to hydrogen bonding interactions with PVA and chitosan chains. Long-term cell culture experiments using normal human dermal fibroblast (NHDF) cells showed that the hydrogels maintained their biocompatibility, and the cells showed extended morphology on the surface of the hydrogels for more than 30 days. The presence of honey significantly increased the biocompatibility of the hydrogels. The release of allantoin from the hydrogel was studied and, according to the Korsmeyer–Peppas and Weibull models, the mechanism was mainly diffusional. The results for the antimicrobial activity against E. coli and S. aureus bacteria showed that the allantoin-containing samples had a more remarkable antibacterial activity against S. aureus. According to the wound healing experiments, 98% of the wound area treated by the chitosan/PVA/honey hydrogel was closed, compared to 89% for the control. The results of this study suggest that the freeze–thaw process is a non-toxic crosslinking method for the preparation of chitosan/PVA hydrogels with long term biocompatibility that can be applied for wound healing and skin tissue engineering