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Thermo physical Properties

Haishi Qiao, Jing Jia, Wei Chen, Bin Di, Oren A Scherman, Chi Hu
The fabrication, characterization, and therapy efficiency of a noncovalent-bonded hydrogel network, which is assembled by utilizing cucurbit[7]uril as a supramolecular linker to "stick" superparamagnetic γ-Fe2 O3 nanoparticles onto the polymer backbone of catechol-functionalized chitosan are described. The unique barrel-shaped structure of cucurbit[7]uril not only facilitates host-guest recognition with the catechol derivatives, but also forms robust electrostatic interactions between its carbonyl portals and the γ-Fe2 O3 nanoparticles in a supramolecular manner, which leaves the physical and chemical properties of the nanoparticles intact...
December 13, 2018: Advanced Healthcare Materials
Sunday Samuel Sobowale, Oluwatoyin Habibat Animashaun, Antoine Floribert Mulaba-Bafubiandi, Temitope Saratallahi Abidoye, Yusuf Olamide Kewuyemi, Oluwafemi Ayodeji Adebo
The current industrial demand for starchy foods has been dominated by other roots and tubers, while cocoyam, despite being rich in fiber, minerals, and vitamins has remained under exploited. In this study, the effect of feed moisture content (FMC), screw speed (SS) and barrel temperature (BT) on the quality characteristics of cocoyam noodles (proximate, thermo-physical, physicochemical, texture, color, extrudate properties, and sensory characteristics) were investigated using central composite design (CCD) of response surface methodology (RSM)...
November 2018: Food Science & Nutrition
Yanping Huang, Nianhua Dan, Weihua Dan, Weifeng Zhao, Zhongxiang Bai, Yining Chen, Changkai Yang
A growth of bacterial infections and over-and inefficient release of antibiotics forces one to search new antibacterial agents and/or strategies. In this study, a novel strategy towards biocompatible and antibacterial bilayer wound dressing was proposed by a two-step spin coating method combined with in-situ crosslinking polymerization. First, through in-situ crosslinking polymerization, [2-(methacryloyloxy) ethyl] trimethylammonium chloride ([MTA][Cl]) was polymerized and crosslinked in polycaprolactone (PCL) solution and PCL/PMTA solution was obtained...
November 28, 2018: International Journal of Biological Macromolecules
Jingjie Yeo, Wenwen Huang, Anna Tarakanova, Yong-Wei Zhang, David L Kaplan, Markus J Buehler
Adaptive hydrogels tailor-made from silk-elastin-like proteins (SELPs) possess excellent biocompatibility and biodegradability with properties that are tunable and responsive to multiple simultaneous external stimuli. To unravel the molecular mechanisms of their physical response to external stimuli in tandem with experiments, here we predict and measure the variation in structural properties as a function of temperature through coarse-grained (CG) modeling of individual and crosslinked SE8Y and S4 E8Y molecules, which have ratios of 1:8 and 4:8 of silk to elastin blocks respectively...
June 14, 2018: Journal of Materials Chemistry. B, Materials for Biology and Medicine
Javier Conesa-Egea, Noemí Nogal, José Ignacio Martínez, Vanesa Fernández-Moreira, Ulises R Rodríguez-Mendoza, Javier González-Platas, Carlos J Gómez-García, Salomé Delgado, Félix Zamora, Pilar Amo-Ochoa
One-pot reactions between CuI and methyl or methyl 2-amino-isonicotinate give rise to the formation of two coordination polymers (CPs) based on double zig-zag Cu2 I2 chains. The presence of a NH2 group in the isonicotinate ligand produces different supramolecular interactions affecting the Cu-Cu distances and symmetry of the Cu2 I2 chains. These structural variations significantly modulate their physical properties. Thus, both CPs are semiconductors and also show reversible thermo/mechanoluminescence. X-ray diffraction studies carried out under different temperature and pressure conditions in combination with theoretical calculations have been used to rationalize the multi-stimuli-responsive properties...
November 7, 2018: Chemical Science
Yukako Tsujimoto, Mai Morimoto, Naotaka Nitta, Iwaki Akiyama
PURPOSE: Tissue characterization in terms of the differences in thermo-physical properties of biological tissues was investigated in this study. The objective was to measure the ratio of variation in sound velocity due to ultrasonic heating and to derive the relational expression between the ratio and thermo-physical properties. METHODS: The ratio of sound velocity variation before and after the temperature rise of tissue samples exposed to ultrasound was measured by ultrasonic pulse echo method...
November 15, 2018: Journal of Medical Ultrasonics
Paola Sánchez-Moreno, Juan de Vicente, Stefania Nardecchia, Juan A Marchal, Houria Boulaiz
Progress in nanotechnology has enabled us to open many new fronts in biomedical research by exploiting the peculiar properties of materials at the nanoscale. The thermal sensitivity of certain materials is a highly valuable property because it can be exploited in many promising applications, such as thermo-sensitive drug or gene delivery systems, thermotherapy, thermal biosensors, imaging, and diagnosis. This review focuses on recent advances in thermo-sensitive nanomaterials of interest in biomedical applications...
November 13, 2018: Nanomaterials
Juan R Chamorro, Tyrel M McQueen
Ages of history are defined by the underlying materials that promoted human development: stone, bronze, and iron ages. Since the middle of the last century, humanity has lived in a silicon age, where the development of the transistor ushered in new technologies previously thought inconceivable. But as technology has advanced, so have the requirements for new materials to sustain increasing physical demands. The field of solid state chemistry is dedicated to the discovery of new materials and phenomena, and though most materials discoveries in history have been through serendipity rather than careful reaction design, the last few decades have seen an increase in the number of materials discovered through a consideration of chemical reaction kinetics and thermodynamics...
October 9, 2018: Accounts of Chemical Research
Ho Cm Brian, Otto Lt Lam, Nithya Jagannathan, Michael G Botelho
AIM: This article aims to systematically review the evidence reporting on physical properties of bonded amalgam, its clinical performance, and implications. MATERIALS AND METHODS: An electronic search in "Medline" (search term: Amalgam and Dentin bonding) from 1987 to 2013 yielded 465 publications out of which 170 articles were selected for the analysis. Data were extracted relating to the bond strength of amalgam to dentin, microleakage, postoperative sensitivity, and longevity of bonded amalgam restorations...
August 1, 2018: Journal of Contemporary Dental Practice
Kartikkumar Thakkar, Keyur Shah, Pravin Kodgire, Surendra Singh Kachhwaha
The present study demonstrates innovative and industrially viable in-situ biodiesel production process using coordinated ultrasound-microwave reactor. Reactive extraction process has been carried out by mixing grinded castor seeds with methanol in the presence of base catalyst (KOH). Response surface methodology coupled with central composite design has been applied for process optimization to achieve maximum yield. The result shows that maximum biodiesel yield of 93.5 ± 0.76% was obtained under favorable conditions of: molar ratio (350:1), catalyst (w/w) (1...
January 2019: Ultrasonics Sonochemistry
Zhe Yang, Xuemei Han, Hiang Kwee Lee, Gia Chuong Phan-Quang, Charlynn Sher Lin Koh, Chee Leng Lay, Yih Hong Lee, Yue-E Miao, Tianxi Liu, In Yee Phang, Xing Yi Ling
Nanoporous gold (NPG) promises efficient light-to-heat transformation, yet suffers limited photothermal conversion efficiency owing to the difficulty in controlling its morphology for the direct modulation of thermo-plasmonic properties. Herein, we showcase a series of shape-controlled NPG nanoparticles with distinct bowl- (NPG-B), tube- (NPG-T) and plate-like (NPG-P) structures for quantitative temperature regulation up to 140 °C in <1 s using laser irradiation. Notably, NPG-B exhibits the highest photothermal efficiency of 68%, which is >12 and 39 percentage points better than those of other NPG shapes (NPG-T, 56%; NPG-P, 49%) and Au nanoparticles (29%), respectively...
August 30, 2018: Nanoscale
Zhijie Qin, Qiulin Yue, Yan Liang, Jingjing Zhang, Lin Zhou, Orlando Borrás Hidalgo, Xinli Liu
Quantum dots are important fluorescent semiconductor nano-crystals with distinguished electrical and optical properties and have gained great interest in many fields. The chemical and physical synthetic methods are usually not favorable for biological application due to high energy-consumption procedure and residual toxic chemicals. The development of novel "green" routes to prepare bio-compatible cadmium sulfide quantum dots constitutes a promising substituted approach. We used the white rot fungus Trametes versicolor for the biosynthesis of cadmium sulfide quantum dots taking account of the adsorption property of this fungus...
October 20, 2018: Journal of Biotechnology
Jinfu Zhao, Zhanqiang Liu, Qi Shen, Bing Wang, Qingqing Wang
Physical Vapor Deposition (PVD) Ti1- x Al x N coated cemented carbide tools are commonly used to cut difficult-to-machine super alloy of Inconel 718. The Al concentration x of Ti1- x Al x N coating can affect the coating microstructure, mechanical and thermo-physical properties of Ti1- x Al x N coating, which affects the cutting temperature in the machining process. Cutting temperature has great influence on the tool life and the machined surface quality. In this study, the influences of PVD (Ti,Al)N coated cemented carbide tools on the cutting temperature were analyzed...
July 25, 2018: Materials
Bui Quoc Bao, Ngoc Hoang Le, Diem Huong Tran Nguyen, Tuong Vi Tran, Linh Phuong Tran Pham, Long Giang Bach, Hieu Minh Ho, Thi Hiep Nguyen, Dai Hai Nguyen
The development of nanomaterials in the field of biomedical has attracted much attention in the past decades. New mesoporous nanosilica (MNS) generation, called multi functionalized MNS, presents the promising applications for efficient encapsulation, controlled release, and intracellular delivery of therapeutic agents due to their unique physiochemical properties, such as large surface area and pore volume, tunable particle size, biocompatibility, and high loading capacity. In this review, we intensively discussed the multi functionalized MNSs that respond to the demand of physical stimuli (thermo, light, magnetic field, ultrasound, and electricity), chemical stimuli (pH, redox, H2 O2 ), and biological stimuli (enzyme, glucose, ATP), individual or in combination...
October 1, 2018: Materials Science & Engineering. C, Materials for Biological Applications
G Montalbano, S Toumpaniari, A Popov, P Duan, J Chen, K Dalgarno, W E Scott, A M Ferreira
Hydrogels based on natural polymers offer a range of properties to mimic the native extracellular matrix, and provide microenvironments to preserve cellular function and encourage tissue formation. A tri-component hydrogel using collagen, alginate and fibrin (CAF) was developed and investigated at three collagen concentrations for application as a functional extracellular matrix analogue. Physical-chemical characterization of CAF hydrogels demonstrated a thermo-responsive crosslinking capacity at physiological conditions with stiffness similar to native soft tissues...
October 1, 2018: Materials Science & Engineering. C, Materials for Biological Applications
Jose M Ortiz-Roldan, Gustavo Esteban-Manzanares, Sergio Lucarini, Sofía Calero, Javier Segurado, Francisco Montero-Chacón, A Rabdel Ruiz-Salvador, Said Hamad
The development of new interatomic potentials to model metallic systems is a difficult task, due in part to the dependence between the parameters that describe the electron density and the short-range interactions. Parameter search methods are prone to false convergence. To solve this problem, we have developed a methodology for obtaining the electron density parameters independently of the short-range interactions, so that physically sound parameters can be obtained to describe the electron density, after which the short-range parameters can be fitted, thus reducing the complexity of the process and yielding better interatomic potentials...
July 11, 2018: Physical Chemistry Chemical Physics: PCCP
Hanna J M Wolff, Michael Kather, Hans Breisig, Walter Richtering, Andrij Pich, Matthias Wessling
Microgels are commonly synthesized in batch experiments, yielding quantities sufficient to perform characterization experiments for physical property studies. With increasing attention on the application potential of microgels, little attention is yet paid to the questions (a) whether they can be produced continuously on a larger scale, (b) whether synthesis routes can be easily transferred from batch to continuous synthesis, and (c) whether their properties can be precisely controlled as a function of synthesis parameters under continuous flow reaction conditions...
July 25, 2018: ACS Applied Materials & Interfaces
Kiersten M Ruff, Stefan Roberts, Ashutosh Chilkoti, Rohit V Pappu
Proteins and synthetic polymers can undergo phase transitions in response to changes to intensive solution parameters such as temperature, proton chemical potentials (pH), and hydrostatic pressure. For proteins and protein-based polymers, the information required for stimulus-responsive phase transitions is encoded in their amino acid sequence. Here, we review some of the key physical principles that govern the phase transitions of archetypal intrinsically disordered protein polymers (IDPPs). These are disordered proteins with repetitive amino acid sequences...
November 2, 2018: Journal of Molecular Biology
Yasmin Khambhaty, R Akshaya, C Rama Suganya, Kalarical Janardhanan Sreeram, Jonnalagadda Raghava Rao
Driven by the environmental benefits that bio-bleaching could bring, the interest in xylanase has received enormous attention and hence, the search of xylanase with properties like no cellulase activity, function at elevated temperatures and pH continues. The present study reports the production of extracellular xylanase from Aspergillus nidulans using waste agro-residues as substrate. The optimum temperature (60 °C) and pH (9.0), classified the xylanase as thermo and alkali tolerant. The addition of salt of Mn2+ increased the xylanase activity to almost double; however, these ions were unable to protect the enzyme from thermal inactivation...
October 15, 2018: International Journal of Biological Macromolecules
Ji Chen, Qiwei Hu, Leiming Fang, Duanwei He, Xiping Chen, Lei Xie, Bo Chen, Xin Li, Xiaolin Ni, Cong Fan, Akun Liang
Crystal solubility is one of the most important thermo-physical properties and plays a key role in industrial applications, fundamental science, and geoscientific research. However, high-pressure in situ measurements of crystal solubility remain very challenging. Here, we present a method involving high-pressure neutron diffraction for making high-precision in situ measurements of crystal solubility as a function of pressure over a wide range of pressures. For these experiments, we designed a piston-cylinder cell with a large chamber volume for high-pressure neutron diffraction...
May 2018: Review of Scientific Instruments
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