Recent Advances in Organic Light-Emitting Diodes Based on Pure Organic Room Temperature Phosphorescence Materials

Pure organic room temperature phosphorescence (RTP) materials have attracted extensive attention in recent years due to their unique characteristics, such as flexible design method, low toxicity, low cost, as well as the ease of production at scale. The involvement of triplet state and direct radiative transition from the triplet state show that RTP materials have great potential as a new generation emitter in organic light-emitting diodes (OLEDs). Based on the mechanism of phosphorescence, various methods have been developed to achieve RTP emissions in the crystal state. However, the observation of RTP in the thin film state is much more difficult to achieve because of the lower degree of rigidity and suppression of the non-radiative transition. In this mini-review, molecular design strategies developed to achieve RTP emissions and their application in OLEDs are summarized and discussed. The conclusion and outlook point to great potential as well as the challenges for the continued study of pure organic RTP materials-based OLEDs

Acylation of Lignin with Different Acylating Agents by Mechanical Activation-Assisted Solid Phase Synthesis: Preparation and Properties

Acylated lignins with substituents consisting of different lengths of carbon chains were prepared by a mechanical activation-assisted solid phase synthesis (MASPS) technology with a customized stirring ball mill as a reactor. The structures and properties were analyzed by UV/Vis, FTIR, NMR, SEM, DSC, and TG. The results showed that the acylated lignins were successfully prepared with either non-cyclic or cyclic anhydrides as the acylating agents. Both aliphatic hydroxyl and phenolic hydroxyl groups of lignin reacted with non-cyclic anhydrides, and different reactivity of acylating agents resulted in different relative contents of phenolic and aliphatic substituents in the products. The reactivity of the cyclic anhydrides was weaker than that of the non-cyclic anhydrides, and the reactivity of the acylating agents decreased with increasing carbon chain length and unsaturated bonds of acyl groups. All of the acylated lignins except maleylated lignin had a lower glass transition temperature (Tg) than the original lignin. The acylated lignins prepared with non-cyclic anhydrides had better thermal stability than original lignin, and the thermal stability increased, but Tg decreased with an increasing chain length of the acyl groups. The acylated lignins prepared with cyclic anhydrides had higher a Tg than those with non-cyclic anhydrides with the same carbon number, and the thermal stability was not obviously improved

Solid-Phase Synthesis of Cellulose Acetate Butyrate as Microsphere Wall Materials for Sustained Release of Emamectin Benzoate

Emamectin benzoate (EB), a widely used pesticide, is prone to decomposition by ultraviolet light and suffers from the corresponding loss of efficacy. The timed release of EB based on microspheres is one of the effective methods to solve this issue. As a non-toxic cellulose ester, cellulose acetate butyrate (CAB) is regarded as one of the best wall-forming materials for microcapsules with a good controlled release performance. Herein, two methods—mechanical activation (MA) technology and a conventional liquid phase (LP) method—were employed to synthesize different CABs, namely CAB-MA and CAB-LP, respectively. The molecular structure, rheological property, and thermal stability of these CABs were investigated. The two CABs were used to prepare microspheres for the loading and release of EB via an o/w (oil-in-water) solvent evaporation method. Moreover, the performances such as drug loading, drug entrapment, and anti-photolysis of the drug for these microspheres were studied. The results showed that both CABs were available as wall materials for loading and releasing EB. Compared with CAB-LP, CAB-MA presented a lower molecular weight and a narrower molecular weight distribution. Moreover, the MA method endowed the CAB with more ester substituent groups and less crystalline structure in comparison to the LP method, which had benefits including pelletizing and drug loading

Overcoming biomass recalcitrance by synergistic pretreatment of mechanical activation and metal salt for enhancing enzymatic conversion of lignocellulose

Abstract Background Due to biomass recalcitrance, including complexity of lignocellulosic matrix, crystallinity of cellulose, and inhibition of lignin, the bioconversion of lignocellulosic biomass is difficult and inefficient. The aim of this study is to investigate an effective and green pretreatment method for overcoming biomass recalcitrance of lignocellulose. Results An effective mechanical activation (MA) + metal salt (MAMS) technology was applied to pretreat sugarcane bagasse (SCB), a typical kind of lignocellulosic biomass, in a stirring ball mill. Chlorides and nitrates of Al and Fe showed better synergistic effect with MA, especially AlCl3, ascribing to the interaction between metal salt and oxygen-containing groups induced by MA. Comparative studies showed that MAMS pretreatment effectively changed the recalcitrant structural characteristics of lignocellulosic matrix and reduced the inhibitory action of lignin on enzymatic conversion of SCB. The increase in hydroxyl and carboxyl groups of lignin induced by MAMS pretreatment led to the increase of its hydrophilicity, which could weaken the binding force between cellulase and lignin and reduce the nonproductive binding of cellulase enzymes to lignin. Conclusions MAMS pretreatment significantly enhanced the enzymatic digestibility of polysaccharides substrate by overcoming biomass recalcitrance without the removal of lignin from enzymatic hydrolysis system

In Situ Synthesis of a Stable Fe₃O₄@Cellulose Nanocomposite for Efficient Catalytic Degradation of Methylene Blue

To rapidly obtain a stable Fe3O4@cellulose heterogeneous Fenton catalyst, a novel in situ chemical co-precipitation method was developed. Compared with mechanical activation (MA)-pretreated cellulose (MAC), MA + FeCl3 (MAFC)-pretreated cellulose (MAFCC) was more easily dissolved and uniformly distributed in NaOH/urea solvent. MAFCC and MAC solutions were used as precipitators to prepare Fe3O4@MAFCC and Fe3O4@MAC nanocomposites, respectively. MAFCC showed stronger interaction and more uniform combination with Fe3O4 nanoparticles than MAC, implying that MAFC pretreatment enhanced the accessibility, reactivity, and dissolving capacity of cellulose thus, provided reactive sites for the in situ growth of Fe3O4 nanoparticles on the regenerated cellulose. Additionally, the catalytic performance of Fe3O4@MAFCC nanocomposite was evaluated by using for catalytic degradation of methylene blue (MB), and Fe3O4@MAC nanocomposite and Fe3O4 nanoparticles were used for comparative studies. Fe3O4@MAFCC nanocomposite exhibited superior catalytic activity for the degradation and mineralization of MB in practical applications. After ten cycles, the structure of Fe3O4@MAFCC nanocomposite was not significantly changed owing to the strong interaction between MAFCC and Fe3O4 nanoparticles. This study provides a green pathway to the fabrication of a stable nanocomposite catalyst with high catalytic performance and reusability for the degradation of organic pollutants

Preparation of a Stable Nanoscale Manganese Residue-Derived FeS@Starch-Derived Carbon Composite for the Adsorption of Safranine T

To develop a novel, low-cost adsorbent with natural material and industrial waste as raw materials, nanoscale manganese residue-derived FeS@starch-derived carbon (MR–FeS@SC) composite was prepared by the carbonization of starch–manganese residue gel. Manganese residue-derived FeS (MR–FeS) and starch-derived carbon (SC) were also prepared as contrasts for comparative studies. The MR–FeS@SC nanocomposite exhibited relatively large specific surface area and micropore volume, appropriate pore size, abundant functional groups, strong interaction between the functional groups of SC and MR–FeS, and the immobilization and uniform distribution of MR–FeS nanoparticles onto SC support material, which contributed to better adsorption properties for the removal of Safranine T (ST) from the aqueous solution compared with those of MR–FeS and SC. The adsorption could be conducted at a wide range of pH and temperature to achieve a satisfy removal efficiency of ST with MR–FeS@SC nanocomposite as adsorbent. The adsorption kinetics well followed the pseudo-second-order model, and the dominant mechanism was chemisorption. The adsorption behavior was well described by the Langmuir isotherm model. Due to the strong interaction between MR–FeS nanoparticles and SC support, MR–FeS@SC nanocomposite exhibited better reusability and stability even after fifteen cycles. This study provides a facile method of preparing effective and stable adsorbents for the treatment of dye wastewater

Effectiveness of ombitasvir/paritaprevir/ritonavir, dasabuvir for HCV in HIV/HCV coinfected subjects: a comprehensive analysis

Abstract Background Data on the treatment of patients with hepatitis C virus (HCV)/human immunodeficiency virus (HIV) coinfection remains limited. A comprehensive analysis was performed to evaluate the efficacy and safety of ombitasvir (OBV)/paritaprevir (PTV)/ritonavir(r) ± dasabuvir (DSV) ± ribavirin (RBV) for treatment in HCV/HIV coinfected patients. Methods We systematically searched and included studies that enrolled patients with HIV/HCV coinfection using the OBV/PTV/r ± DSV ± RBV regimens and reported sustained virological response after 12 weeks (SVR12) end-of-treatment. Heterogeneity of results was assessed and pooled SVR rates were computed with 95% confidence intervals (95%CI). Subgroup analysis and assessment of publication bias through Egger’s test were further performed. Results Ten studies containing 1358 coinfected patients were included in this study. The pooled estimate of SVR12 was 96.3% (95%CI: 95.1–97.4). Subgroup analysis showed that pooled SVR12 rate was 96.2% (95% CI: 94.8–97.4) for patients with genotype (GT) 1 and 98.8% (95% CI: 95.1–100.0) for those with GT4. The SVR12 rates for the treatment-naïve (TN) and treatment-experienced (TE) patients were 96.8% (95% CI, 94.8–98.5) and 98.9% (95% CI, 96.4–100.0), respectively. Pooled SVR12 rate was 97.8(95%CI: 94.6–99.8) for patients with cirrhosis and 96.7% (95%CI: 95.3–97.8) without cirrhosis. The pooled incidence of any adverse events (AEs) and serious adverse events (SAEs) was 73.9% (95%CI: 38.1–97.6) and 2.7% (95%CI: 0.0–9.5). Publication bias did not exist in this study. Conclusions The comprehensive analysis showed high efficacy for the OBV/PTV/r ± DSV ± RBV regimen in patients coinfected with HIV and HCV, regardless of genotypes, history of treatment and the presence or absence of cirrhosis