Yong Hua¹,Bolun Chen^1,2,∗,Yan Yuan¹, Guochang Zhu¹, Fenfen Li¹

Journal on Internet of Things, Vol.1, No.2, pp. 77-88, 2019, DOI:10.32604/jiot.2019.05941

Abstract The problem of influence maximization in the social network G is to find k seed nodes with the maximum influence. The seed set S has a wider range of influence in the social network G than other same-size node sets. The influence of a node is usually established by using the IC model (Independent Cascade model) with a considerable amount of Monte Carlo simulations used to approximate the influence of the node. In addition, an approximate effect (1-1/e) is obtained, when the number of Monte Carlo simulations is 10000 and the probability of propagation is very small. In this paper,… More >

F.J. Santiago-Medina¹, M.C. Basso¹, A. Pizzi^1,2,*, L. Delmotte³

Journal of Renewable Materials, Vol.6, No.4, pp. 413-425, 2018, DOI:10.7569/JRM.2017.634172

Abstract The reaction of a desulphurized kraft lignin with hexamethylene diamine and dimethyl carbonate has allowed the development of isocyanate-free polyurethane resins. The present research work is based on previous studies made with hydrolyzable and condensed tannins, but takes advantage of the higher number of hydroxyl groups present in lignin and their different aliphatic and aromatic character. The obtained materials were analyzed by Fourier transform infrared (FTIR) spectroscopy, matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry and solid-state cross-polarization/magic angle spinning (CP MAS) 13 C nuclear magnetic resonance (NMR), which have revealed the presence of urethane functions. The interpretation of the… More >

A. M. Borrero-López¹, F. J. Santiago-Medina¹, C. Valencia^1,2*, M. E. Eugenio³, R. Martin-Sampedro³, J. M. Franco^1,2

Journal of Renewable Materials, Vol.6, No.4, pp. 347-361, 2018, DOI:10.7569/JRM.2017.634160

Abstract It is known that large amounts of residual lignin are generated in the pulp and paper industry. A new alternative for Kraft lignin valorization, which consists of first a chemical modification using a diisocyanate and then the efficient dispersion in castor oil to achieve stable gel-like systems, is proposed in this work. Rheological properties and microstructure of these materials were determined by means of small amplitude oscillatory shear tests and viscous flow measurements and atomic force microscopy observations, respectively. Moreover, both standardized penetration tests and tribological assays, usually performed in the lubricant industry, were carried out to evaluate the performance… More >

Luis Daniel Mora-Murillo¹, Felipe Orozco-Gutierrez², José Vega-Baudrit², Rodolfo Jesús González-Paz^2*

Journal of Renewable Materials, Vol.5, No.3-4, pp. 220-230, 2017, DOI:10.7569/JRM.2017.634112

Abstract Nowadays, green polyurethane (PU) foams are mostly synthesized by replacing an amount of petrochemical polyol with biobased polyol. Here we report five different families of isocyanate prepolymer formulations that were prepared with biobased sources and the correlation between the structure of chains and the properties of the produced PU foam. Foam behavior in tension, torsion, compression, shape memory tests and physical properties were studied by dynamic mechanical thermal analysis (DMTA); interactions in the polymer chains were analyzed by Fourier transform infrared spectroscopy (FTIR); and thermal analysis was performed by thermogravimetry (TGA) and differential scanning calorimetry (DSC). The results showed that… More >

María Cecilia Basso^1*, Antonio Pizzi^1,2

Journal of Renewable Materials, Vol.5, No.1, pp. 48-53, 2017, DOI:10.7569/JRM.2016.634124

Abstract New aldehyde-free and isocyanate-free biofoams have been obtained by reacting albumin chicken egg white and dimethyl carbonate (DMC). The optimized formulations yielded lightweight foams whose densities were evaluated as 0.016–0.16 g/cm3. Mechanical resistance was 0.023–0.34 MPa and residual pH nearly neutral. The new foams presented up to 57% of closed cells as measured by helium pycnometry and good thermal insulation. These new natural foams are environmentally friendly materials and show very promising properties. More >

M. Thébault^1,2, A. Pizzi1^3*, F.J. Santiago-Medina¹, F.M. Al-Marzouki³, S. Abdalla³

Journal of Renewable Materials, Vol.5, No.1, pp. 21-29, 2017, DOI:10.7569/JRM.2016.634116

Abstract Isocyanate-free polyurethane resins biosourced to a very high percentage level were prepared by the reaction of aminated mimosa tannin extract with commercial mimosa tannin extract prereacted with dimethyl carbonate. The reaction took place with ease at ambient temperature. Indications were that the polyurethanes obtained formed a hard film when cured at a temperature higher than 100 °C. Furthermore, the carbohydrate fraction of the tannin extract also appeared to be carbonated and reacted to generate isocyanate-free polyurethane linkages with the aminated tannins. This indicated that not only the polyphenolic fraction of the tannin extract, but also its other major component, can… More >

Aleksander Prociak^*, Elźbieta Malewska, Szymon Bąk

Journal of Renewable Materials, Vol.4, No.1, pp. 78-85, 2016, DOI:10.7569/JRM.2015.634129

Abstract In this article, the results of the foaming process analysis of fl exible polyurethane with different isocyanate indexes are presented. Two types of flexible polyurethane foams (FPURF) were obtained: (1) by using petrochemical components and a rapeseed-oil-based polyol (used in the amount of 20 wt%), (2) by using petrochemical components and cellulose as a natural fi ller in the amount of 3 php (per hundred parts of polyol). The characteristic parameters of the foaming process, such as the foam’s growth velocity, the core temperature and dielectric polarization, were measured using a Foamat device. Moreover, the following properties of flexible polyurethane… More >

Wangping Duan^∗, Lei Wei^†, Juntao Zhang^∗, Yongzhuang Hao^∗, Chunjiang Li^∗, Hao Li^∗, Qi Li^∗, Quanyou Zhang^‡, Weiyi Chen^‡, Xiaochun Wei^∗,§

Molecular & Cellular Biomechanics, Vol.8, No.4, pp. 253-274, 2011, DOI:10.3970/mcb.2011.008.253

Abstract The cytoskeleton network is believed to play an important role in the biomechanical properties of the chondrocyte. Ours and other laboratories have demonstrated that chondrocytes exhibit a viscoelastic solid creep behavior in vitro and that viscoelastic properties decrease in osteoarthritic chondrocytes. In this study, we aimed to understand whether the alteration of viscoelastic properties is associated with changes in cytoskeleton components of ageing chondrocytes from rabbit knee articular cartilage. Three age groups were used for this study: young (2-months-old, N=23), adult (8-months-old, N=23), and old (31-months-old, N=23) rabbit groups. Cartilage structure and proteoglycan and type II collagen content were determined… More >

Guanbin Song^∗,†,‡, Qing Luo^*, Baiyao Xu^*, Yang Ju^†

Molecular & Cellular Biomechanics, Vol.7, No.3, pp. 165-174, 2010, DOI:10.3970/mcb.2010.007.165

Abstract It has been demonstrated that mechanical stimulation plays a vital role in regulating the proliferation and differentiation of stem cells. However, little is known about the effects of mechanical stress on tendon/ligament development from mesenchymal stem cells (MSCs). Here, using a custom-made cell-stretching device, we studied the effects of mechanical stretching on the cell morphology and mRNA expression of several key genes modulating tendon/ligament genesis. We demonstrate that bone-marrow-derived rat MSCs (rMSCs), when subjected to cyclic uniaxial stretching, express obvious detectable mRNAs for tenascin C and scleraxis, a unique maker of tendon/ligament formation, and significantly increased levels of type I… More >

Meghan H. Hoskins^*, Cheng Dong^∗,†

Molecular & Cellular Biomechanics, Vol.3, No.2, pp. 79-88, 2006, DOI:10.3970/mcb.2006.003.079

Abstract It has been determined previously that polymorphonuclear leukocytes, or PMNs, can facilitate melanoma cell extravasation through the endothelium under shear conditions [1,2]. The interactions between melanoma cells and PMNs are mediated by the β₂-integrins expressed by PMNs and intercellular adhesion molecules (ICAM-1) expressed on melanoma cells. In this study, the kinetics of these interactions was studied using a parallel plate flow chamber. The dissociation rates were calculated under low force conditions for ICAM-1 interactions with both β₂-integrins, LFA-1 (CD11a/CD18) and Mac-1 (CD11b/CD18), together and separately by using functional blocking antibodies on PMNs. The kinetics of PMNs stimulated with IL-8 was… More >