Synergistic Effect of PVDF-Coated PCL-TCP Scaffolds and Pulsed Electromagnetic Field on Osteogenesis

Bone exhibits piezoelectric properties. Thus, electrical stimulations such as pulsed electromagnetic fields (PEMFs) and stimuli-responsive piezoelectric properties of scaffolds have been investigated separately to evaluate their efficacy in supporting osteogenesis. However, current understanding of cells responding under the combined influence of PEMF and piezoelectric properties in scaffolds is still lacking. Therefore, in this study, we fabricated piezoelectric scaffolds by functionalization of polycaprolactone-tricalcium phosphate (PCL-TCP) films with a polyvinylidene fluoride (PVDF) coating that is self-polarized by a modified breath-figure technique. The osteoinductive properties of these PVDF-coated PCL-TCP films on MC3T3-E1 cells were studied under the stimulation of PEMF. Piezoelectric and ferroelectric characterization demonstrated that scaffolds with piezoelectric coefficient d₃₃ = −1.2 pC/N were obtained at a powder dissolution temperature of 100 °C and coating relative humidity (RH) of 56%. DNA quantification showed that cell proliferation was significantly enhanced by PEMF as low as 0.6 mT and 50 Hz. Hydroxyapatite staining showed that cell mineralization was significantly enhanced by incorporation of PVDF coating. Gene expression study showed that the combination of PEMF and PVDF coating promoted late osteogenic gene expression marker most significantly. Collectively, our results suggest that the synergistic effects of PEMF and piezoelectric scaffolds on osteogenesis provide a promising alternative strategy for electrically augmented osteoinduction. The piezoelectric response of PVDF by PEMF, which could provide mechanical strain, is particularly interesting as it could deliver local mechanical stimulation to osteogenic cells using PEMF.     

Particulate structures produced by electrosprays of colloidal silica suspensions in both negative and positive zeta potentials

Interaction between surface charge (zeta potential) of colloidal silica nanoparticles and the charge-induced droplets suspended in the gas phase by electrospray is investigated for the first time based on the particle physical (morphology, size, and size distribution) and optical properties. Colloidal silica nanoparticles having negative and positive zeta potential were subjected to electrospray in both negative and positive mode, and deposited on a substrate (silicon wafer). Visual observation of the substrate with particle deposition shows various white shades, corresponding to the changes in optical properties, as supported by the ultraviolet-visible–near-infrared spectroscopy. Microscopic analysis revealed the strong correlation between the colloid surface charge and charging mode (positive or negative) of the sprayed droplets to the particle morphology and size. The findings of the present study demonstrate the capability of the electrospray method to tune the physical and optical properties of colloidal silica nanoparticles with different surface charges.     

Reinforcement effect of nanocellulose on thermal stability of nitrile butadiene rubber (NBR) composites

Poor physical and chemical attraction between nitrile butadiene rubber (NBR) matrix and filler resulted in low thermal properties. Therefore, nanocrystalline cellulose (NCC) as a reinforcement agent was used to increase the heat resistance and thermal stability of NBR composites. The addition of 2 phr NCC increased thermal stability and activation energy of NBR up to 75%. Meanwhile, the storage modulus of composites increased by 12 GPa at the similar loading of NCC. Good interfacial bonds of electrostatic interactions, formation of hydrogen bonds, crystallinity and nanosized of NCC are the main factors contribute to the final properties of NBR/NCC composites. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46594.     

Characterization of Magnesium Orotate‐Loaded Chitosan Polymer Nanoparticles for a Drug Delivery System

The drug release properties of magnesium orotate (MgOr) encapsulated in the chitosan (CS) cavity and the complexation behavior between MgOr and CS were investigated. The MgOr‐loaded CS nanoparticles (MgOrCSNPs) were characterized by differential scanning calorimetry, Fourier transform infrared spectroscopy, X‐ray diffraction, transmission electron microscopy, and scanning electron microscopy with energy‐dispersive X‐ray spectroscopy. MgOr was successfully encapsulated into the CS cavity. Results with 3‐(4,5‐dimethylthiazol‐2‐yl)2,5‐diphenyl tetrazolium bromide indicated that MgOrCSNPs retained their cytotoxic activity against the liver cancer cell line (HepG2) and breast cancer cell line (MCF‐7), and low toxicity against the human cell line (3T3) and human retinal epithelial cell line (ARPE‐19).     

Demand scenario analysis and planned capacity expansion: A system dynamics framework

This paper establishes an approach to develop models for forecasting demand and evaluating policy scenarios related to planned capacity expansion for meeting optimistic and pessimistic future demand projections. A system dynamics framework is used to model and to generate scenarios because of their capability of representing physical and information flows, which will enable us to understand the nonlinear dynamics behavior in uncertain conditions. These models can provide important inputs such as construction growth, GDP growth, and investment growth to specific business decisions such as planned capacity expansion policies that will improve the system performance.     

Computational methods for Traditional Chinese Medicine: a survey

Traditional Chinese Medicine (TCM) has been actively researched through various approaches, including computational techniques. A review on basic elements of TCM is provided to illuminate various challenges and progresses in its study using computational methods. Information on various TCM formulations, in particular resources on databases of TCM formulations and their integration to Western medicine, are analyzed in several facets, such as TCM classifications, types of databases, and mining tools. Aspects of computational TCM diagnosis, namely inspection, auscultation, pulse analysis as well as TCM expert systems are reviewed in term of their benefits and drawbacks. Various approaches on exploring relationships among TCM components and finding genes/proteins relating to TCM symptom complex are also studied. This survey provides a summary on the advance of computational approaches for TCM and will be useful for future knowledge discovery in this area.     

Assigning service requests in Voice-over-Internet gateway multiprocessors

New and proposed communication systems are entirely digital, including Voice over Internet Protocol tasks as well as traditional data packets, fax, etc. Numerous digital signal processing (DSP) algorithms are available to encode and decode these signals, each having different requirements for data memory, program memory, and processor speed. A DSP multiprocessor having numerous DSP cores receives a stream of requests for encoding and decoding tasks. A service request is “blocked” if no DSP core can handle the task when it arrives. We present algorithms for assigning DSP tasks to cores in order to minimize the number of blocked tasks. This is similar to an online bin-packing problem with the important difference that the program memory can be shared between simultaneous service requests for the same DSP algorithm. Since bin-packing is known to be NP-complete, we develop fast heuristic online methods for this problem.