Preparation and Characterization of SO42-/TiO2-HBeta for Selective Conversion of 1-Methylnaphthalene

In this study, new types of SO42-/TiO2-HBeta (ST/Hβ) catalysts are synthesized and characterized by XRD, IR, N2 adsorption-desorption, ICP-OES, SEM, and NH3-TPD methods. Conversion of 1-methylnaphthalene is carried out in a fixed-bed system. Based on the study's results, the catalysts ST/Hβ showed uniform SO42-/TiO2 (ST) loading, high surface area, and sufficient mild acid sites. When ST content increased, the amount of strong acid sites and by-products decreased. Under atmospheric pressure, catalyst 15-ST/Hβ showed a catalytic performance of 74.1 % conversion and 97.4 % selectivity

Ultrasound regulated flexible protein materials: Fabrication, structure and physical-biological properties.

Ultrasound can be used in the biomaterial field due to its high efficiency, easy operation, no chemical treatment, repeatability and high level of control. In this work, we demonstrated that ultrasound is able to quickly regulate protein structure at the solution assembly stage to obtain the designed properties of protein-based materials. Silk fibroin proteins dissolved in a formic acid-CaCl solution system were treated in an ultrasound with varying times and powers. By altering these variables, the silks physical properties and structures can be fine-tuned and the results were investigated with Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA), gas permeability and water contact angle measurements. Ultrasonic treatment aids the interactions between the calcium ions and silk molecular chains which leads to increased amounts of intermolecular β-sheets and α-helix. This unique structural change caused the silk film to be highly insoluble in water while also inducing a hydrophilic swelling property. The ultrasound-regulated silk materials also showed higher thermal stability, better biocompatibility and breathability, and favorable mechanical strength and flexibility. It was also possible to tune the enzymatic degradation rate and biological response (cell growth and proliferation) of protein materials by changing ultrasound parameters. This study provides a unique physical and non-contact material processing method for the wide applications of protein-based biomaterials

Exploring the Structural Transformation Mechanism of Chinese and Thailand Silk Fibroin Fibers and Formic-Acid Fabricated Silk Films

Silk fibroin (SF) is a protein polymer derived from insects, which has unique mechanical properties and tunable biodegradation rate due to its variable structures. Here, the variability of structural, thermal, and mechanical properties of two domesticated silk films (Chinese and Thailand B. Mori) regenerated from formic acid solution, as well as their original fibers, were compared and investigated using dynamic mechanical analysis (DMA) and Fourier transform infrared spectrometry (FTIR). Four relaxation events appeared clearly during the temperature region of 25 °C to 280 °C in DMA curves, and their disorder degree (fdis) and glass transition temperature (Tg) were predicted using Group Interaction Modeling (GIM). Compared with Thai (Thailand) regenerated silks, Chin (Chinese) silks possess a lower Tg, higher fdis, and better elasticity and mechanical strength. As the calcium chloride content in the initial processing solvent increases (1%–6%), the Tg of the final SF samples gradually decrease, while their fdis increase. Besides, SF with more non-crystalline structures shows high plasticity. Two α- relaxations in the glass transition region of tan δ curve were identified due to the structural transition of silk protein. These findings provide a new perspective for the design of advanced protein biomaterials with different secondary structures, and facilitate a comprehensive understanding of the structure-property relationship of various biopolymers in the futu

Preparation of 2-Methylnaphthalene from 1-Methylnaphthalene via Catalytic Isomerization and Crystallization

Large amounts of residual 1-methylnaphthalene are generated when 2-methylnaphthalene is extracted from alkyl naphthalene. In order to transform waste into assets, this study proposes a feasible process for preparing 2-methylnaphthalene from 1-methylnaphthalene through isomerization and crystallization. The 1-methylnaphthalene isomerization was carried out in a fixed-bed reactor over mixed acids-treated HBEA zeolite. The results showed that acidic properties of catalysts and reaction temperature were associated with the 2-methylnaphthalene selectivity, yield and catalytic stability. At a high reaction temperature of 623 K, the 2-methylnaphthalene yield was 65.84 %, and the deactivation rate was much lower. The separation of reaction products was then investigated by two consecutive crystallization processes. Under optimal conditions, the 2-methylnaphthalene purity attained 96.67 % in the product, while the yield was 87.48 % in the refining process. Copyright © 2018 BCREC Group. All rights reserved Received: 10th May 2018; Revised: 16th July 2018; Accepted: 17th July 2018 How to Cite: Sun, H., Sun, K., Jiang, J., Gu, Z. (2018). Preparation of 2-Methylnaphthalene from 1-Methylnaphthalene via Catalytic Isomerization and Crystallization. Bulletin of Chemical Reaction Engineering & Catalysis, 13 (3): 512-519 (doi:10.9767/bcrec.13.3.2650.512-519) Permalink/DOI: https://doi.org/10.9767/bcrec.13.3.2650.512-51

Recent Advances in Electrospun Sustainable Composites for Biomedical, Environmental, Energy, and Packaging Applications.

Electrospinning has gained constant enthusiasm and wide interest as a novel sustainable material processing technique due to its ease of operation and wide adaptability for fabricating eco-friendly fibers on a nanoscale. In addition, the device working parameters, spinning solution properties, and the environmental factors can have a significant effect on the fibers\u27 morphology during electrospinning. This review summarizes the newly developed principles and influence factors for electrospinning technology in the past five years, including these factors\u27 interactions with the electrospinning mechanism as well as its most recent applications of electrospun natural or sustainable composite materials in biology, environmental protection, energy, and food packaging materials

Tailoring the supramolecular structure of guanidinylated pullulan toward enhanced genetic photodynamic therapy

In the progress of designing a gene carrier system, what is urgently needed is a balance of excellent safety and satisfactory efficiency. Herein, a straightforward and versatile synthesis of a cationic guanidine-decorated dendronized pullulan (OGG3P) for efficient genetic photodynamic therapy was proposed. OGG3P was able to block the mobility of DNA from a weight ratio of 2. However, G3P lacking guanidine residues could not block DNA migration until at a weight ratio of 15, revealing guanidination could facilitate DNA condensation via specific guanidinium-phosphate interactions. A zeta potential plateau (∼+23 mV) of OGG3P complexes indicated the nonionic hydrophilic hydroxyl groups in pullulan might neutralize the excessive detrimental cationic charges. There was no obvious cytotoxicity and hemolysis, but also enhancement of transfection efficiency with regard to OGG3P in comparison with that of native G3P in Hela and HEK293T cells. More importantly, we found that the uptake efficiency in Hela cells between OGG3P and G3P complexes was not markedly different. However, guanidination caused changes in uptake pathway and led to macropinocytosis pathway, which may be a crucial reason for improved transfection efficiency. After introducing a therapeutic pKillerRed-mem plasmid, OGG3P complexes achieved significantly enhanced KillerRed protein expression and ROS production under irradiation. ROS-induced cancer cells proliferation suppression was also confirmed. This study highlights the guanidine-decorated dendronized pullulan could emerge as a reliable nonviral gene carrier to specifically deliver therapeutic genes

Exploring the Structural Transformation Mechanism of Chinese and Thailand Silk Fibroin Fibers and Formic-Acid Fabricated Silk Films

Silk fibroin (SF) is a protein polymer derived from insects, which has unique mechanical properties and tunable biodegradation rate due to its variable structures. Here, the variability of structural, thermal, and mechanical properties of two domesticated silk films (Chinese and Thailand B. Mori) regenerated from formic acid solution, as well as their original fibers, were compared and investigated using dynamic mechanical analysis (DMA) and Fourier transform infrared spectrometry (FTIR). Four relaxation events appeared clearly during the temperature region of 25 °C to 280 °C in DMA curves, and their disorder degree (fdis) and glass transition temperature (Tg) were predicted using Group Interaction Modeling (GIM). Compared with Thai (Thailand) regenerated silks, Chin (Chinese) silks possess a lower Tg, higher fdis, and better elasticity and mechanical strength. As the calcium chloride content in the initial processing solvent increases (1%⁻6%), the Tg of the final SF samples gradually decrease, while their fdis increase. Besides, SF with more non-crystalline structures shows high plasticity. Two α- relaxations in the glass transition region of tan δ curve were identified due to the structural transition of silk protein. These findings provide a new perspective for the design of advanced protein biomaterials with different secondary structures, and facilitate a comprehensive understanding of the structure-property relationship of various biopolymers in the future

Synergistic Removal of Copper(II) and Tetracycline from Water Using an Environmentally Friendly Chitosan-Based Flocculant

In the current work, an environmentally friendly chitosan-based flocculant (carboxyethyl chitosan, denoted as CEC) was prepared to flocculate copper­(II) and tetracycline (TC) simultaneously for the first time. The effects of flocculant dosage, pH, and initial contaminant concentration were systematically studied. For a single contaminant system, CEC demonstrates the desired flocculation performance for copper­(II) removal, whereas its TC removal efficiency is poor. However, it is notable to find that the removal of TC can be significantly enhanced when copper­(II) coexists in the binary contaminant system. Compared to the commercial flocculants polyaluminum chloride and polyacrylamide, CEC enjoys the advantages of lower dosage requirement, higher removal efficiency, and better floc properties. The flocculation mechanism was investigated via pH monitoring, zeta potential, and floc property measurements. The results indicate that charge neutralization predominates for single contaminant copper­(II) removal, while for binary contaminant removal, TC can be embedded in copper­(II) hydroxides through coordination with the metal, and finally synergistically eliminated with copper­(II). This work gives a new approach to treating livestock wastewater and extends the application fields of flocculation

Synthesis of Electroneutralized Amphiphilic Copolymers with Peptide Dendrons for Intramuscular Gene Delivery

Intramuscular gene delivery materials are of great importance in plasmid-based gene therapy system, but there is limited information so far on how to design and synthesize them. A previous study showed that the peptide dendron-based triblock copolymer with its components arranged in a reversed biomembrane architecture could significantly increase intramuscular gene delivery and expression. Herein, we wonder whether copolymers with biomembrane-mimicking arrangement may have similar function on intramuscular gene delivery. Meanwhile, it is of great significance to uncover the influence of electric charge and molecular structure on the function of the copolymers. To address the issues, amphiphilic triblock copolymers arranged in hydrophilic–hydrophobic–hydrophilic structure were constructed despite the paradoxical characteristics and difficulties in synthesizing such hydrophilic but electroneutral molecules. The as-prepared two copolymers, dendronG2­(l-lysine-OH)-poly propylene glycol_2k(PPG_2k)-dendronG2­(l-lysine-OH) (<b>rL</b>_<b>2</b><b>PL</b>_<b>2</b>) and dendronG3­(l-lysine-OH)-PPG_2k-dendronG3­(l-lysine-OH) (<b>rL</b>_<b>3</b><b>PL</b>_<b>3</b>), were in similar structure but had different hydrophilic components and surface charges, thus leading to different capabilities in gene delivery and expression in skeletal muscle. <b>rL</b>_<b>2</b><b>PL</b>_<b>2</b> was more efficient than Pluronic L64 and <b>rL</b>_<b>3</b><b>PL</b>_<b>3</b> when mediating luciferase, β-galactosidase, and fluorescent protein expressions. Furthermore, <b>rL</b>_<b>2</b><b>PL</b>_<b>2</b>-mediated growth-hormone-releasing hormone expression could significantly induce mouse body weight increase in the first 21 days after injection. In addition, both <b>rL</b>_<b>2</b><b>PL</b>_<b>2</b> and <b>rL</b>_<b>3</b><b>PL</b>_<b>3</b> showed good in vivo biosafety in local and systemic administration. Altogether, <b>rL</b>_<b>2</b><b>PL</b>_<b>2</b>-mediated gene expression in skeletal muscle exhibited applicable potential for gene therapy. The study revealed that the molecular structure and electric charge were critical factors governing the function of the copolymers for intramuscular gene delivery. It can be concluded that, combined with the previous study, both structural arrangements either reverse or similar to the biomembrane are effective in designing such copolymers. It also provides an innovative way in designing and synthesizing new electroneutralized triblock copolymers, which could be used safely and efficiently for intramuscular gene delivery

Self-assembly of pH-sensitive fluorinated peptide dendron functionalized dextran nanoparticles for on-demand intracellular drug delivery.

In this study, the amphiphilic fluorinated peptide dendrons functionalized dextran (FPD-HZN-Dex) via an acid-sensitive hydrazone linkage was successfully designed and prepared for the first time. We demonstrated a spontaneous self-assembly of amphiphilic FPD-HZN-Dex into the well-defined nanoparticles with the core-shell architecture in aqueous media, which is attributed to the efficient amphiphilic functionalization of dextran by the hydrophobic fluorinated peptide dendrons. The spherical morphology, uniform particle size and good storage stability of the prepared FPD-HZN-Dex nanoparticles were characterized by dynamic light scattering and transmission electron microscopy, respectively. In vitro drug release studies showed a controlled and pH dependent hydrophobic drug release profile. The cell viability assays show excellent biocompatibility of the FPD-HZN-Dex nanoparticles for both normal cells and tumor cells. Moreover, the FPD-HZN-Dex self-assembled systems based on pH-sensitive hydrazone linkage also can serve as stimulus bioresponsive carriers for on-demand intracellular drug delivery. These self-assembled nanoparticles exhibit a stimulus-induced response to endo/lysosome pH (pH 5.0) that causes their disassembly over time, enabling controlled release of encapsulated DOX. This work has unveiled a unique non-covalent interaction useful for engineering amphiphilic dendrons or dendrimers self-assembled systems.The European Commission Research and Innovation (PIRSES-GA-2011-295218