Fabrication of a pilot scale module of thin film composite hollow fiber membrane for osmotic pressure‐driven processes

Polyamide thin film composite hollow fiber membranes have advantages in their unique structure compared to flat sheet membranes. This study examined interfacial polymerization methods for fabricating pilot scale hollow fiber membranes (membrane area: 1.2 m², number of hollow fiber strands: 1200). For use in osmotic pressure‐driven processes, a one‐pot hydrophilic interfacial polymerization procedure was developed simultaneously to modify the surface property and synthesize polyamide thin film. With the procedure, a pilot scale module has a water flux of 13 LMH using a draw solution of 0.6M NaCl and a feed solution of distilled water through the design of the module configuration. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46110.     

Pyrolysis and co-pyrolysis of Laminaria japonica and polypropylene over mesoporous Al-SBA-15 catalyst

The catalytic co-pyrolysis of a seaweed biomass, Laminaria japonica, and a typical polymer material, polypropylene, was studied for the first time. A mesoporous material Al-SBA-15 was used as a catalyst. Pyrolysis experiments were conducted using a fixed-bed reactor and pyrolysis gas chromatography/mass spectrometry (Py-GC/MS). BET surface area, N₂ adsorption-desorption isotherms, and NH₃ temperature programmed desorption were measured to examine the catalyst characteristics. When only L. japonica was pyrolyzed, catalytic reforming slightly increased the gas yield and decreased the oil yield. The H₂O content in bio-oil was increased by catalytic reforming from 42.03 to 50.32 wt% due to the dehydration reaction occurring on the acid sites inside the large pores of Al-SBA-15. Acids, oxygenates, mono-aromatics, poly aromatic hydrocarbons, and phenolics were the main components of the bio-oil obtained from the pyrolysis of L. japonica. Upon catalytic reforming over Al-SBA-15, the main oxygenate species 1,4-anhydro-d-galactitol and 1,5-anhydro-d-manitol were completely removed. When L. japonica was co-pyrolyzed with polypropylene, the H₂O content in bio-oil was decreased dramatically (8.93 wt% in the case of catalytic co-pyrolysis), contributing to the improvement of the oil quality. A huge increase in the content of gasoline-range and diesel-range hydrocarbons in bio-oil was the most remarkable change that resulted from the co-pyrolysis with polypropylene, suggesting its potential as a transport fuel. The content of mono-aromatics with high economic value was also increased significantly by catalytic co-pyrolysis.     

Molecular dynamics and thermal analysis study of anomalous thermodynamic behavior of poly (ether imide)/polycarbonate blends

Molecular dynamics simulation used to study the binary polymer blend of poly (ether imide) (PEI) and polycarbonate (PC) showed that these polymer blends are immiscible. The Flory-Huggins interaction parameter, χ, calculated from simulation reached a minimum value at 80 wt% PEI. The simulation results showed that the concentration dependence of χ was mainly due to electrostatic interaction and van der Waals force. The simulation results were supported by differential scanning calorimetry (DSC) measurements. The DSC measurements showed that there are two distinct glass transition temperatures for all the blends' concentrations. However, at 80wt % PEI, the T_g of PEI-rich phase reached a minimum while that of the PC-rich phase was comparable to its pure form indicating that there is some partial miscibility of PC in the PEI rich phase, but no PEI is incorporated in the PC rich phase. From simulations, the χ versus concentration plot shows the same trend as the experimentally measured glass transition temperature versus concentration plot.     

Material Design for 3D Multifunctional Hydrogel Structure Preparation

Hydrogels are recognized as one of the most promising materials for e-skin devices because of their unique applicable functionalities such as flexibility, stretchability, biocompatibility, and conductivity. Beyond the excellent sensing functionalities, the e-skin devices further need to secure a target-oriented 3D structure to be applied onto various body parts having complex 3D shapes. However, most e-skin devices are still fabricated in simple 2D film-type devices, and it is an intriguing issue to fabricate complex 3D e-skin devices resembling target body parts via 3D printing. Here, a material design guideline is provided to prepare multifunctional hydrogels and their target-oriented 3D structures based on extrusion-based 3D printing. The material design parameters to realize target-oriented 3D structures via 3D printing are systematically derived from the correlation between material design of hydrogels and their gelation characteristics, rheological properties, and 3D printing processability for extrusion-based 3D printing. Based on the suggested material design window, ion conductive self-healable hydrogels are designed and successfully applied to extrusion-based 3D printing to realize various 3D shapes.     

Facile Deposition of Silver Nanoparticles on Photonic Cellulose Nanocrystals Films: A Study on Solvent Stability and Post Antibacterial Activity

Cellulose nanocrystals (CNCs) incorporated with silver nanoparticles (AgNPs) photonic films have drawn considerable attention due to their plasmonic chiroptical activity. However, the exploitation of some fundamental properties for practical use such as the affinity analysis of metal nanoparticles attached to the surface of photonic films according to the solvent compatibility and antibacterial activity under physical conditions has yet not been studied. Hence, a facile process of in situ deposition of AgNPs into the chiral structure of CNC films is proposed. CNC photonic films, cross-linked by glutaraldehyde are prepared. This interaction generated the solvents-stable photonic film with a considerable amount of unreacted aldehyde functional groups that facilitates the reduction of Ag salt to AgNPs. The formed AgNPs in the photonic films show excellent stability over immersion in various polar and non-polar solvents. The post-solvent treated photonic films display excellent contact-based antibacterial behavior against gram-negative Escherichia coli.     

PLEKHA8P1 Promotes Tumor Progression and Indicates Poor Prognosis of Liver Cancer

Hepatocellular carcinoma (HCC) records the second-lowest 5-year survival rate despite the avalanche of research into diagnosis and therapy. One of the major obstacles in treatment is chemoresistance to drugs such as 5-fluorouracil (5-FU), making identification and elucidation of chemoresistance regulators highly valuable. As the regulatory landscape grows to encompass non-coding genes such as long non-coding RNAs (lncRNAs), a relatively new class of lncRNA has emerged in the form of pseudogene-derived lncRNAs. Through bioinformatics analyses of the TCGA LIHC dataset, we have systematically identified pseudogenes of prognostic value. Initial experimental validation of selected pseudogene-derived lncRNA (PLEKHA8P1) and its parental gene (PLEKHA8), a well-studied transport protein in Golgi complex recently implicated as an oncogene in both colorectal and liver cancer, indicates that the pseudogene/parental gene pair promotes tumor progression and that their dysregulated expression levels affect 5-FU-induced chemoresistance in human HCC cell line FT3-7. Our study has thus confirmed cancer-related functions of PLEKHA8, and laid the groundwork for identification and validation of oncogenic pseudogene-derived lncRNA that shows potential as a novel therapeutic target in circumventing chemoresistance induced by 5-FU.     

Optimization of sensitizer concentration for upconversion photoluminescence of Yb3+/Er3+: La10W22O81 nanophosphor rods

Yb³⁺/Er³⁺codoped La₁₀W₂₂O₈₁ (LWO) nanophosphor rods have been successfully synthesized by a facile hydrothermal assisted solid state reaction method, and their upconversion photoluminescence properties were systematically studied. X-ray diffraction patterns revealed that the nanophosphors have an orthorhombic structure with space group Pbcn (60). A microflowers-like morphology with irregular hexagonal nanorods was observed using field emission scanning electron microscopy for the Yb³⁺(2 mol%)/Er³⁺(2 mol%):LWO nanophosphor. The shape and size of the nanophosphor and the elements along with their ionic states in the material were confirmed by TEM and XPS studies, respectively. A green upconversion emission was observed in the Er³⁺: LWO nanophosphors under 980 nm laser excitation. A significant improvement in upconversion emission has been observed in the Er³⁺: LWO nanophosphors by increasing the Er³⁺ ion concentration. A decrease in the upconversion emission occurred due to concentration quenching when the doping concentration of Er³⁺ ions was greater than 2 mol%. An optimized Er³⁺(2 mol%): LWO nanophosphor exhibited a strong near infrared emission at 1.53 μm by 980 nm excitation. The green upconversion emission of Er³⁺(2 mol%): LWO was remarkably enhanced by co-doping with Yb³⁺ ions under 980 nm excitation because of energy transfer from Yb³⁺ to Er³⁺. The naked eye observed this upconversion emission when co-doping with 2 mol% Yb³⁺. In order to obtain the high upconversion green emission, the optimized sensitizer concentration of Yb³⁺ ions was found to be 2 mol%. The upconversion emission trends were studied as a function of stimulating laser power for an optimized sample. Moreover, the NIR emission intensity has also been enhanced by co-doping with Yb³⁺ ions due to energy transfer from Yb³⁺ to Er³⁺. The energy transfer dynamics were systematically elucidated by energy level scheme. Colorimetric coordinates were determined for Er³⁺ and Yb³⁺/Er³⁺: LWO nanophosphors. The energy transfer mechanism was well explained and substantiated by several fluorescence dynamics of upconversion emission spectra and CIE coordinates. The results demonstrated that the co-doped Yb³⁺(2 mol%)/Er³⁺(2 mol%): LWO nanophosphor material is found to be a suitable candidate for the novel upconversion photonic devices.     

Polymerization of styrene in a continuous filled tubular reactor

Free radical solution polymerization of styrene has been studied using a binary mixture of symmetrical bifunctional initiators in a filled tubular reactor packed with static mixers. Owing to intensive radial mixing induced by the static mixers, a near plug flow pattern was obtained in the reactor with some axial dispersion effect. The axial mass dispersion coefficient was determined from the residence time distribution experiment and a dynamic axial dispersion model has been developed and solved to investigate steady state and transient behavior of the filled tubular reactor. With a solvent volume fraction of 0.3, the monomer conversion up to 70% was obtained without fouling problems in the temperature range 90 to 120°C. The experimental filled tubular reactor was operated under various reaction conditions and a reasonably good agreement between the model and the experimental data was obtained without using any adjustable parameters.     

Microwave Dielectric Properties of CaTiO3-Ca(Al1/2Ta1/2)O3 Ceramics

The microwave dielectric properties of CaTi_1-χ(Al_1/2Ta_1/2)_cHO₃ solid solutions (0.3 ≤χ≤ 0.5) have been investigated. The ceramic samples had perovskite structures similar to CaTiO₃. The partial substitution of Ti₄₊ by a coupled Al₃₊/Ta_s+ permitted improvement of the quality factor Q . The dielectric constant (τ_r) and temperature coefficient of resonant frequency (τ_r) decrease rapidly with an increase of χ. A new high-quality microwave dielectric material was found at χ= 0.46 with σ_r= 46.5, Q f = 27300 GHz, and π_f= 0 ppm/°C. The relationship between microstructures and dielectric properties is presented.