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Electrospun Fibrous Silk Fibroin/Poly(L-Lactic Acid) Scaffold for Cartilage Tissue Engineering
Weiwei Liu,Zhengqiang Li,Lu Zheng,Xiaoyan Zhang,Peng Liu,Ting Yang,Bing Han 한국조직공학과 재생의학회 2016 조직공학과 재생의학 Vol.13 No.5
For successful tissue engineering of articular cartilage, a scaffold with mechanical properties that match those of natural cartilage as closely as possible is needed. In the present study, we prepared a fibrous silk fibroin (SF)/poly(L-lactic acid) (PLLA) scaffold via electrospinning and investigated the morphological, mechanical, and degradation properties of the scaffolds fabricated using different electrospinning conditions, including collection distance, working voltage, and the SF:PLLA mass ratio. In addition, in vitro cell-scaffold interactions were evaluated in terms of chondrocyte adhesion to the scaffolds as well as the cytotoxicity and cytocompatibility of the scaffolds. The optimum electrospinning conditions for generating a fibrous SF/PLLA scaffold with the best surface morphology (ordered alignment and suitable diameter) and tensile strength (~1.5 MPa) were a collection distance of 20 cm, a working voltage of 15 kV, and a SF:PLLA mass ratio of S50P50. The degradation rate of the SF/PLLA scaffolds was found to be determined by the SF:PLLA mass ratio, and it could be increased by reducing the PLLA proportion. Furthermore, chondrocytes spread well on the fibrous SF/PLLA scaffolds and secreted extracellular matrix, indicating good adhesion to the scaffold. The cytotoxicity of SF/PLLA scaffold extract to chondrocytes over 24 and 48 h in culture was low, indicating that the SF/PLLA scaffolds are biocompatible. Chondrocytes grew well on the SF/PLLA scaffold after 1, 3, 5, and 7 days of direct contact, indicating the good cytocompatibility of the scaffold. These results demonstrate that the fibrous SF/PLLA scaffold represents a promising composite material for use in cartilage tissue engineering.
Incorporating price preferences for product recommendation in electronic commerce
Han Chen,Weiwei Deng 한국지능정보시스템학회 2022 한국지능정보시스템학회 학술대회논문집 Vol.2022 No.6
Product recommendation methods have become the cornerstone of electronic commerce platforms due to their ability to solve the information overload problem and inform customers about their potentially interesting products. However, previous recommendation methods fail to consider customers’ price preferences, which are essential in recommending suitable products. To bridge this gap, this study proposes a hybrid recommendation method that combines customer behaviors, product content, and price preferences for product recommendations. In the proposed method, two strategies are designed to model customers’ price preferences. The proposed method is evaluated with a real-world data set and compared with three baseline methods. The evaluation results show that the proposed recommendation method with either strategy significantly outperforms the three baseline methods in terms of precision, recall. F-score, and mean average precision (MAP) measures.
A multimodal deep learning approach for online course recommendation
Weiwei Deng,Lingjun Fu,Han Chen 한국지능정보시스템학회 2022 한국지능정보시스템학회 학술대회논문집 Vol.2022 No.6
With the rapid development of massive open online course (MOOC) platforms, learners are overloaded by numerous online courses. Many online course recommendation methods have been developed to facilitate learners to find suitable courses on the platforms. However, existing methods mainly focus on mining textual data and are inflexible to incorporate other types of data, which also benefit course recommendation. To bridge this gap, we propose a multimodal deep learning approach that leverages multiple types of course data for online course recommendation. The proposed approach employs multiple embedding techniques to process textual, relational, and categorical course data and uses the processed data to profile courses and learners for course recommendation. Experimental results on a real-world dataset show that the proposed approach outperforms multiple baselines in terms of precision and mean average precision.
Coexistence of OSCR-Based IR-UWB System with IEEE 802.11a WLAN
Weiwei Wu,Han Huang,Huarin Yin,Weidong Wang,Dongjin Wang 한국전자통신연구원 2006 ETRI Journal Vol.28 No.1
Impulse radio (IR) is a competitive candidate for ultra-wideband (UWB) systems. In this letter, we evaluated the coexistence of an IR-UWB system based on an orthogonal sinusoidal correlation receiver (OSCR) with an IEEE 802.11a WLAN through a detailed simulation. The coexistence performance of the two systems is characterized in terms of the receiver’s bit-error rates. Then, some approaches to interference mitigation are discussed.
Amplification at 1400–1450 nm of the Large-Core Nd-Doped Fiber by White LED Pumping
Lin Htein,Weiwei Fan,Watekar, P. R.,Won-Taek Han IEEE 2013 Photonics Technology Letters Vol.25 No.11
<P>A novel cost-effective fiber amplifier operating over 1400-1450 nm is developed based on pumping of a large-core Nd-doped fiber with a high-power white light-emitting diode (LED). An optical gain of 6 dB at 1400 nm is obtained by simultaneously exciting the multiple absorption bands in the visible wavelength of the Nd-doped fiber.</P>
( Yuying Wang ),( Xue Yan ),( Weiwei Zhang ),( Yuanyuan Liu ),( Deping Han ),( Kedao Teng ),( Yunfei Ma ) 한국미생물생명공학회(구 한국산업미생물학회) 2019 Journal of microbiology and biotechnology Vol.29 No.6
Farm animals such as piglets are often affected by environmental stress, which can disturb the gut ecosystem. Antibiotics were commonly used to prevent diarrhea in weaned piglets, but this was banned by the European Union due to the development of antibiotic resistance. However, the use of probiotics instead of antibiotics may reduce the risk posed by pathogenic microorganisms and reduce the incidence of gastrointestinal diseases. Therefore, this study was conducted to investigate the effects of Lactobacillus casei Zhang on the mechanical barrier and immune function of early-weaned piglets infected using Escherichia coli K88 based on histomorphology and immunology. Fourteen-day-old weaned piglets were divided into a control group and experimental groups that were fed L. casei Zhang and infected with E. coli K88 with or without prefeeding and/or postfeeding of L. casei Zhang. The L. casei Zhang dose used was 107 CFU/g diet. Jejunum segments were obtained before histological, immunohistochemical, and western blot analyses were performed. In addition, the relative mRNA expression of toll receptors and cytokines was measured. Piglets fed L. casei Zhang showed significantly increased jejunum villus height, villus height-crypt depth ratio, muscle thickness, and expression of proliferating cell nuclear antigen and tight junction proteins ZO-1 and occludin. The use of L. casei Zhang effectively reduced intestinal inflammation after infection. We found that L. casei Zhang feeding prevented the jejunum damage induced by E. coli K88, suggesting that it may be a potential alternative to antibiotics for preventing diarrhea in early-weaned piglets.
Feng Ye,Yanpeng Cao,Weiwei Han,Yakun Yang,Yuancheng Feng,Peng Liu,Chao Xu,Xiaoze Du,양우철,Liu Guicheng 한국화학공학회 2022 Korean Journal of Chemical Engineering Vol.39 No.3
A highly active RuO2IrO2 electrocatalyst was developed via dip-coating/calcination method for oxygen evolution reaction (OER). The catalyst on Ti substrate with a 7/3 molar ratio between Ru and Ir showed the highest electrocatalytic activity for OER among composite samples in different molar ratios. Moreover, the properties of RuO2IrO2 grown on carbon paper were evaluated by proton exchange membrane water electrolysis single cell. Compared with the micron-particle structure of RuO2IrO2 catalyst on the Ti substrate, the catalyst grown on the carbon paper showed a novel nano dendrite shape and can be used directly as the gas diffusion electrode. Owing to the large surface area of the catalyst, the nano dendrite-shaped RuO2IrO2 catalyst exhibits excellent OER performance in the single cell. Furthermore, a cell voltage of 2.50 V is achieved under 200mA cm2 at 30 oC by using the optimal composition RuO2IrO2 (Ru : Ir=7/3) and the commercial 20% Pt/C as anode and cathode, respectively.
Amplification by white light-emitting diode pumping of large-core Er-doped fiber with 12 dB gain.
Htein, Lin,Fan, Weiwei,Watekar, Pramod R,Han, Won-Taek Optical Society of America 2012 Optics letters Vol.37 No.23
<P>We have developed a cost-effective, high-capacity Er-doped fiber amplifier based on the high-power white LED and a large-core Er-doped fiber. Er ions of the fiber with absorption bands at 453, 488, 523, and 654 nm were simultaneously excited by LED pumping and amplification with optical gain over 12 dB at 1550 nm was obtained.</P>
Structural evolution of the thermal conversion products of modified coal tar pitch
Qi Li,Dongyun Han,Haiyan Qiao,Weiwei Shi,Yuqi Zhang,Zubin Cao 한국탄소학회 2023 Carbon Letters Vol.33 No.1
Coal tar pitch is a product with high carbon content and aromatic compounds. Modified coal tar pitch is a high quality raw material for the preparation of intermediate phase pitch, needle coke, carbon microspheres, et al. In this paper, modified coal tar pitch was used as raw material, nitrogen was used as protective gas, and thermal conversion was carried out at constant temperatures (370, 390, 410, 420 °C). Polarized light microscopy, SEM, elemental analysis, FTIR spectroscopy, Raman spectroscopy and XRD diffraction combined with split-peak fitting were used to characterize the microstructures of the thermal transformation products. The results showed that the Iar and CH3/ CH2 contents of the products increased with the gradual increase of the thermal conversion temperature, and the aromatic content increased. And the higher the temperature at the same heating rate, the more the ideal graphite microcrystal content, and the defective graphite microcrystals are converted into ideal graphite microcrystals during the thermal conversion process. When the reaction temperature exceeds 390 °C, the microstructure of the thermal transformation products is anisotropic spheres, and the small spheres fuse with each other and tend to be basin-like and mosaic structure as the temperature increases.