排序方式: 共有28条查询结果,搜索用时 15 毫秒
1.
Joe Kelly Mark Leonard Chutima Tantigate Ahmad Safari 《Journal of the American Ceramic Society》1997,80(4):957-964
Ceramic lead magnesium niobate–lead titanate ((1-x)PMN-x PT) of different compositions has been prepared by the columbite precursor method. This study discusses compositions ranging from 0.94PMN–0.06PT to 0.60PM–N0.40PT, focusing on two areas of the (1-x)PMNx PT system: compositions that exhibit electrostrictive behavior, and those that show piezoelectric behavior. In electrostrictive compositions where x is in the range of 0.06–0.20, the dielectric constant and electromechanical coupling factor dependencies on the bias field are evaluated. The optimal electromechanical properties are obtained with the composition 0.82PMN–0.18PT, measured at temperature T = Tm (the temperature of maximum dielectric constant) = 80°C and with a dc bias of 5 kV/cm. X–ray diffractometry is used to show that the (1-x)PMN-x PT system has a compositionally wide two–phase region and that 0.655PMN–0.345PT is the morphotropic phase boundary (MPB) composition. Electromechanical property evaluation shows that the optimal piezoelectric properties (piezoelectric charge coefficient ( d33 ) value of 720 pC/N, dielectric constant ( K ) value of 5400, and electromechanical planar and thickness coupling coefficient ( kp and kt , respectively) values of 62% and 46%, respectively) are obtained at the MPB composition. 相似文献
2.
Chutima Wiranidchapong Waraporn Kieongarm Chittima Managit Watoo Phrompittayarat 《Drug development and industrial pharmacy》2016,42(4):644-653
AbstractThe objective of this study was to investigate thermal and mechanical properties as well as in vitro drug release of Eudragit® RL (ERL) film using chlorpheniramine maleate (CPM) as either active pharmaceutical ingredient or non-traditional plasticizer. Differential scanning calorimeter was used to measure the glass transition temperature (Tg) of 0–100% w/w CPM in ERL physical mixture. Instron testing machine was used to investigate Young’s modulus, tensile stress and tensile strain (%) of ERL film containing 20–60% w/w CPM. Finally, a Franz diffusion cell was used to study drug release from ERL films obtained from four formulations, i.e. CRHP0/0, CRHP0/5, CRHP2/0 and CRHP2/5. The Tg of ERL was decreased when the weight percentage of CPM increased. The reduction of the Tg could be described by Kwei equation, indicating the interaction between CPM and ERL. Modulus and tensile stress decreased whereas tensile strain (%) increased when weight percentage of CPM increased. The change of mechanical properties was associated with the reduction of the Tg when weight percentage of CPM increased. ERL films obtained from four formulations could release the drug in no less than 10?h. Cumulative amount of drug release per unit area of ERL film containing only CPM (CRHP0/0) was lower than those obtained from the formulations containing traditional plasticizer (CRHP0/5), surfactant (CRHP2/0) or both of them (CRHP2/5). The increase of drug release was a result of the increase of drug permeability through ERL film and drug solubility based on traditional plasticizer and surfactant, respectively. 相似文献
3.
Theoretical and practical considerations in electrostatic depositioning of charged polymers 下载免费PDF全文
An interfacial engineering technology, based on the electrostatic deposition of charged polyelectrolytes onto surfaces of oppositely charged templates is reviewed with an emphasis on practical applications in the food, pharmaceutical and personal care industries. On interfaces of disperse systems consecutively deposited polymers provide major advantages in terms of physical and chemical stability of dispersions against superimposed stresses (pH, temperature, ionic strength, freezing, chilling, dehydration, lipid oxidation). The controlled deposition of multiple layers allows for a controlled and triggered release of incorporated functional components. This review highlights the basic principles of the layer‐by‐layer (LbL) electrostatic deposition method as well as some major advantages and drawbacks of this approach. An overview of several systems that can be used as templates for the deposition including emulsion droplets, liposomal vehicles, colloidal aggregates, and planar surfaces is given. Suitable substrates for the deposition are presented with a focus on charged biopolymers such as proteins or polysaccharides since they play an essential role in the formulation and stabilization of food, pharmaceutical and personal care applications. Issues and difficulties associated with implementing the technology on a larger, industrial scale are discussed. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40099. 相似文献
4.
Soottawat Benjakul Chutima Thongkaew Wonnop Visessanguan 《European Food Research and Technology》2005,220(3-4):316-321
Effects of different reducing agents (cysteine, ascorbic acid and sodium bisulfite) at various levels on physicochemical properties of protein, transglutaminase activity and gel properties of surimi produced from frozen croaker, lizardfish, threadfin bream and bigeye snapper were studied. Addition of cysteine resulted in the highest increase in the breaking force and the deformation of surimi gels, compared with other reducing agents. The optimum levels of cysteine were 0.05, 0.1, 0.05 and 0.1% (w/w) for surimi from frozen croaker, lizardfish, threadfin bream and bigeye snapper, respectively. Surimi from frozen croaker with cysteine added showed a similar breaking force and deformation to that produced from fresh fish. With addition of cysteine, an increase in sulfhydryl content with a concomitant decrease in disulfide bond content was generally observed. Ca2+ ATPase activity also increased, indicating the renaturation of the myosin molecule. Tmax of peak 1 (myosin peak) of all surimi sols in the presence of cysteine was shifted to higher temperature. The increased transglutaminase activity was observed with addition of cysteine. Therefore, reducing agents, especially cysteine, recovered the denatured muscle proteins and activated the transglutaminase in the muscle, leading to the increased gel-forming ability of surimi produced from frozen fish. 相似文献
5.
In this work, an efficient and simple method to graft a vinylsulfonic acid sodium salt on a poorly water‐soluble chitosan is described. Commercially available low molecular weight chitosan is converted to water‐soluble chitosan containing hyperbranched‐vinylsulfonic acid sodium salt groups. The process comprises the following steps: Michael addition of methyl acrylate, amidation with ethylenediamine, and Michael addition of vinylsulfonic acid sodium salt. A variety of chitosans containing vinylsulfonic acid sodium salt, with improved water solubility, is synthesized by repeating these three steps. The new chitosan derivatives show better antimicrobial activity against Micrococcus luteus ATCC 10240 and Achromobacter xylosoxidans ATCC 2706. In addition, they display better chelating behavior with heavy metals, like cadmium(II), copper(II), and nickel(II), than the starting chitosan. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 相似文献
6.
Structural and Biochemical Studies of Actin in Complex with Synthetic Macrolide Tail Analogues 下载免费PDF全文
Dr. Jose H. Pereira Dr. Chutima Petchprayoon Dr. Alexander C. Hoepker Dr. Nigel W. Moriarty Dr. Sarah J. Fink Dr. Giuseppe Cecere Prof. Ian Paterson Prof. Paul D. Adams Prof. Gerard Marriott 《ChemMedChem》2014,9(10):2286-2293
The actin filament‐binding and filament‐severing activities of the aplyronine, kabiramide, and reidispongiolide families of marine macrolides are located within the hydrophobic tail region of the molecule. Two synthetic tail analogues of aplyronine C (SF‐01 and GC‐04) are shown to bind to G‐actin with dissociation constants of (285±33) and (132±13) nM , respectively. The crystal structures of actin complexes with GC‐04, SF‐01, and kabiramide C reveal a conserved mode of tail binding within the cleft that forms between subdomains (SD) 1 and 3. Our studies support the view that filament severing is brought about by specific binding of the tail region to the SD1/SD3 cleft on the upper protomer, which displaces loop‐D from the lower protomer on the same half‐filament. With previous studies showing that the GC‐04 analogue can sever actin filaments, it is argued that the shorter complex lifetime of tail analogues with F‐actin would make them more effective at severing filaments compared with plasma gelsolin. Structure‐based analyses are used to suggest more reactive or targetable forms of GC‐04 and SF‐01, which may serve to boost the capacity of the serum actin scavenging system, to generate antibody conjugates against tumor cell antigens, and to decrease sputum viscosity in children with cystic fibrosis. 相似文献
7.
Chutima Ganthavorn Joe S. Hughes 《Journal of the American Oil Chemists' Society》1997,74(8):1025-1030
Polyphenolic compounds were extracted from pinto, kidney, white (Great Northern), pink, and black beans by hot methanol extraction
and added to soybean oil. Oil oxidation was assayed by thiobarbituric acid-reactive substances (TBARS). All bean polyphenolics
extracts exhibited similar antioxidant capacity in delaying the onset of iron-catalyzed oxidation better than butylated hydroxyanisole
(BHA), propyl gallate (PG), and ascorbic acid. Bean polyphenolic compounds were stable after heating to 50°C and maintained
their antioxidant potential after 3 mon at 4°C. Bean extracts effectively inhibited iron-catalyzed oxidation of soybean oil,
probably by chelating metal ions, because no antioxidant effect was observed when soybean oil was oxidized without an iron
catalyst. 相似文献
8.
Spelling speech recognition can be applied for several purposes including enhancement of speech recognition systems and implementation of name retrieval systems. This paper presents a Thai spelling analysis to develop a Thai spelling speech recognizer. The Thai phonetic characteristics, alphabet system and spelling methods have been analyzed. As a training resource, two alternative corpora, a small spelling speech corpus and an existing large continuous speech corpus, are used to train hidden Markov models (HMMs). Then their recognition results are compared to each other. To solve the problem of utterance speed difference between spelling utterances and continuous speech utterances, the adjustment of utterance speed has been taken into account. Two alternative language models, bigram and trigram, are used for investigating performance of spelling speech recognition. Our approach achieves up to 98.0% letter correction rate, 97.9% letter accuracy and 82.8% utterance correction rate when the language model is trained based on trigram and the acoustic model is trained from the small spelling speech corpus with eight Gaussian mixtures. 相似文献
9.
Chamchoy Kwandee Thiangtrong Apichaya Pisitsak Penwisa Vanichvattanadecha Chutima 《Journal of Porous Materials》2022,29(2):381-391
Journal of Porous Materials - In this work, a novel application of whey protein isolate (WPI) for surface coating of magnetic nanoparticles (MNPs) is demonstrated. WPI-modified MNPs (WPI-MNPs) were... 相似文献
10.
EXPERIMENTAL STUDY ON DRYING OF CHILLI IN A COMBINED MICROWAVE-VACUUM-ROTARY DRUM DRYER 总被引:7,自引:0,他引:7
This paper presents new data on drying chilli in a microwave-vacuum-rotary drum dryer. This novel technique is designed to combine the advantages of vacuum drying and evenly dispersed microwave energy in a rotary drum. The drying kinetic and the specific energy consumption at particular product moisture content were measured experimentally. Moreover, the effect of pressure inside the chamber and the rotational speed of the drum were also determined. 相似文献