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651.
Piezoelectric transducers are becoming increasingly popular for dynamic strain monitoring due to their small form factors
and their ability to generate an electrical voltage drop in response to strain. Although numerous types of piezoelectric thin
films have been adopted for strain sensing, it has been shown that piezo-ceramics are expensive, brittle, and can fail during
operation, while piezo-polymers possess lower piezoelectricity and mechanical stiffness. Thus, the objective of this study
is to develop a piezoelectric thin film characterized by high piezoelectricity (i.e., high dynamic strain sensitivities) and
favorable mechanical properties (i.e., being conformable to structural surfaces yet stiff). First, zinc oxide (ZnO) nanoparticles
are dispersed in polyelectrolyte solutions, and the excess solvent is evaporated for thin film fabrication. The amount of
ZnO nanoparticles embedded within the films is varied to yield seven unique sample sets with ZnO weight fractions ranging
from 0 to 60%. Upon film fabrication, specimens are mounted in a load frame for monotonic uniaxial testing to explore the
films’ stress–strain performance and to subsequently determine their mechanical properties (namely, modulus of elasticity,
ultimate strength, and ultimate failure strain). Finally, film specimens are also mounted onto cantilevered beams undergoing
free vibration due to an applied initial displacement. The generated voltages in response to induced strains in the beams
are recorded, and the piezoelectric performance and dynamic strain sensitivities for the different weight fraction films are
calculated and compared. Commercial PVDF thin films are also employed in this study for performance comparison. 相似文献
652.
Wong Cheng Lee Candy Haley Lim Kenry Chenliang Su Kian Ping Loh Chwee Teck Lim 《Small (Weinheim an der Bergstrasse, Germany)》2015,11(8):963-969
Graphene‐based nanomaterials are increasingly being explored for use as biomaterials for drug delivery and tissue engineering applications due to their exceptional physicochemical and mechanical properties. However, the two‐dimensional nature of graphene makes it difficult to extend its applications beyond planar tissue culture. Here, graphene–cell biocomposites are used to pre‐concentrate growth factors for chondrogenic differentiation. Bone marrow‐derived mesenchymal stem cells (MSCs) are assembled with graphene flakes in the solution to form graphene‐cell biocomposites. Increasing concentrations of graphene (G) and porous graphene oxide (pGO) are found to correlate positively with the extent of differentiation. However, beyond a certain concentration, especially in the case of graphene oxide, it will lead to decreased chondrogenesis due to increased diffusional barrier and cytotoxic effects. Nevertheless, these findings indicate that both G and pGO could serve as effective pre‐concentration platforms for the construction of tissue‐engineered cartilage and suspension‐based cultures in vitro. 相似文献
653.
Molecular Hemocompatibility of Graphene Oxide and Its Implication for Antithrombotic Applications 下载免费PDF全文
Kenry Kian Ping Loh Chwee Teck Lim 《Small (Weinheim an der Bergstrasse, Germany)》2015,11(38):5105-5117
Surface‐induced blood clotting is one of the major problems associated with the long‐term use of blood‐contacting biomedical devices. Central to this obstructive blood clotting is the adsorption of plasma proteins following the interactions between blood and material surface. Of all proteins circulating in the blood plasma, albumin and fibrinogen are the two important proteins regulating the blood–material interaction. As such, the adsorption of plasma proteins has been used as an indicator for the assessment of the blood compatibility of the biomedical devices. Numerous nanomaterials have been developed for antithrombotic surface coating applications, including the 2D graphene and its derivatives. Here, the antithrombotic property of albumin‐functionalized graphene oxide (albumin‐GO) and its potential for antithrombotic coating application under flow are investigated. The loading capacities, conformational changes, and adsorptions of albumin and fibrinogen on GO are probed. It is observed that GO possesses a high loading capacity for both proteins and simultaneously, it does not disrupt the overall secondary structure and conformational stability of albumin. Both albumin and fibrinogen adsorb well on the surface of GO. Subsequently, it is demonstrated that the albumin‐functionalized GO possesses enhanced antithrombotic effect and may potentially be used as an antithrombotic coating material of blood‐contacting devices under dynamic flow. 相似文献
654.
Kai Bin Liew Gabriel Onn Kit Loh Yvonne Tze Fung Tan 《Drug development and industrial pharmacy》2014,40(9):1156-1162
Context: Although the general pharmacokinetics of cephalexin is quite established up-to-date, however, no population-based study on Cephalexin pharmacokinetics profile in Malay population has been reported yet in the literature.Objective: The objective of this study was to investigate the pharmacokinetics and to compare the bioavailability of three cephalexin products, Ospexin® versus MPI Cephalexin® tablet and MPI Cephalexin® capsule, in healthy Malay ethnic male volunteers in Malaysia.Material and method: A single dose, randomized, fasting, three-period, three-treatment, three-sequence crossover, open label bioequivalence study was conducted in 24 healthy Malay adult male volunteers, with 1 week washout period. The drug concentration in the sample was analyzed using high performance liquid chromatography.Result: The mean (SD) pharmacokinetic parameter results of Ospexin® were Cmax, 17.39 (4.15) μg/mL; AUC0–6, 28.90 (5.70) µg/mL?*?h; AUC0–∞, 30.07 (5.94) µg/mL?*?h; while, those of MPI Cephalexin® tablet were Cmax, 18.29 (3.01) μg/mL; AUC0–6, 30.02 (4.80) µg/mL?*?h; AUC00–∞, 31.33 (5.18) µg/mL?*?h and MPI Cephalexin® capsule were Cmax, 18.25 (3.92) μg/mL; AUC0–6, 30.04 (5.13) µg/mL?*?h; AUC0–∞, 31.22 (5.29) µg/mL?*?h.Conclusion: The 90% confidence intervals for the logarithmic transformed Cmax, AUC0–6 and AUC0–∞, of Ospexin® versus MPI Cephalexin® tablet and Ospexin® versus MPI Cephalexin® capsule were between 0.80 and 1.25. Both Cmax and AUC met the predetermined criteria for assuming bioequivalence. The pharmacokinetic profile of cephalexin in Malay population does not vary much from other world population. 相似文献
655.
A. N. Sung M. M. Ratnam W. P. Loh 《The International Journal of Advanced Manufacturing Technology》2014,74(1-4):139-150
Most of the theoretical models for surface roughness in finish turning assume that the work piece surface profile is formed by the rounded tip of the tool nose. The effect of the straight flank section in the tool nose region on the surface roughness is usually neglected. In this work, the straight flank section is taken into account in order to predict the arithmetic average roughness R a and root-mean-square roughness R q more accurately. The analytical models for R a and R q are developed as a function of three parameters, namely feed rate, nose radius, and wedge angle. These models were verified using digital simulation method. The surface roughness determined using the new three-parameter models were compared with the existing two-parameter models that consider only the feed rate and nose radius. Decreasing wedge angle was found to lower the surface roughness significantly. An experiment was conducted to test the validity of the three-parameter model at different feed rates in real machining operation. The experimental results agreed more closely with the proposed three-parameter models compared to the two-parameter models. 相似文献
656.
657.
Michael T.M. Wang Kalaivarny Ganesalingam Chee Seang Loh Trisha Alberquerque Suhaila Al-Kanani Stuti L. Misra Jennifer P. Craig 《Contact lens & anterior eye》2017,40(1):53-58
Purpose
To assess the effects of two weeks of regular phospholipid liposomal spray application on lipid layer grade, tear film stability, subjective comfort, visual acuity, and lipid deposition in silicone hydrogel contact lens wearers.Methods
Thirty-one existing contact lens wearers were enrolled and fitted with two week planned replacement silicone hydrogel contact lenses (Acuvue® Oasys®) in a prospective, randomized, paired-eye, investigator-masked trial. A phospholipid liposomal spray (Tears Again®) was applied to one eye (randomized) four times daily for two weeks. LogMAR high contrast visual acuity (VA), low contrast glare acuity (LCGA), non-invasive tear film break-up time (NIBUT), and lipid layer grade (LLG) were measured at baseline and day 14, in both treated and control eyes. Subjective comfort relative to baseline, and spectrofluorophotometric assessment of contact lens surface lipid deposition were also assessed on day 14.Results
All measurements did not differ at baseline between treated and control eyes. Lipid layer thickness and tear film stability were increased on day 14 in treated eyes (all p < 0.05), but not in control eyes (all p > 0.05). A greater proportion of participants reported improved comfort in the treated eye relative to the control eye (p = 0.002). There were no significant differences in visual acuity or in contact lens surface lipid deposition, between treated and control eyes, on day 14 (all p > 0.05).Conclusion
The phospholipid liposomal spray increased tear film stability, lipid layer thickness and subjective comfort in silicone hydrogel contact lens wearers, without adversely affecting visual acuity or contact lens surface lipid deposition. 相似文献658.
ZhiBin Xie Anupam Midya Kian Ping Loh Stefan Adams Daniel John Blackwood John Wang Xuanjun Zhang Zhikuan Chen 《Progress in Photovoltaics: Research and Applications》2010,18(8):573-581
Two novel organic dyes have been synthesized using electron rich phenothiazine as electron donors and oligothiophene vinylene as conjugation spacers. The two dyes (2E)‐2‐cyano‐3‐(5‐(5‐((E)‐2‐(10‐(2‐ethylhexyl)‐10H‐phenothiazin‐7‐yl)vinyl)thiophen‐2‐yl)thiophen‐2‐yl)acrylic acid (PTZ‐1) and (2E)‐3‐(5‐(5‐(4,5‐bis((E)‐2‐(10‐(2‐ethylhexyl)‐10H‐phenothiazin‐3‐yl)vinyl)thiophen‐2‐yl)thiophen‐2‐yl)thiophen‐2‐yl)‐2‐cyanoacrylic acid (PTZ‐2) were fully characterized and employed in dye‐sensitized solar cells (DSCs) to explore the effect of disubstituted donors on photovoltaic (PV) performance. The solar cells sensitized by the PTZ1 dye have a high IPCE plateau of 80% and achieve a short‐circuit photocurrent density of 12.98 mA/cm2, an open‐circuit voltage of 0.713 V, and a fill factor (ff) of 66.6%, corresponding to a conversion efficiency of 6.17% under AM 1.5 100 mW/cm2 illumination. The different performance of the solar cells based on the two dyes can be understood from the studies of the electron kinetics by electrochemical impedance spectroscopy (EIS). These investigations reveal that disubstituted donors in the organic sensitizers of three or more conjugation units deteriorate the PV performance due to enhanced recombination. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
659.
Laura Hanske Gunnar Loh Silke Sczesny Michael Blaut Annett Braune 《Molecular nutrition & food research》2010,54(10):1405-1413
The impact of human intestinal bacteria on the bioavailability of the prenylflavonoid xanthohumol (XN) was studied by comparing germ‐free (GF) and human microbiota‐associated (HMA) rats. After XN application, XN, XN conjugates, and isoxanthohumol (IX) conjugates occurred in blood samples of GF and HMA rats, whereas IX was detected only in the blood of HMA rats. Overall excretion of XN and its metabolites within 48 h was only 4.6% of the ingested dose in GF rats and 4.2% in HMA rats, feces being the major route of excretion. While both GF and HMA rats excreted XN, IX, and their conjugates with urine and feces, 8‐prenylnaringenin and its corresponding conjugates were exclusively observed in the feces of HMA rats. The microbial formation of 8‐prenylnaringenin was confirmed by incubation of XN and IX with human fecal slurries. The amount of conjugates excreted in urine and feces was lower in HMA rats compared to GF rats indicating their hydrolysis by human intestinal microbiota. Thus, the impact of bacteria on the XN metabolism in the gut may affect the in vivo effects of ingested XN. 相似文献
660.
Siti Salwa Hashim Mahendra Rao Somalu Kee Shyuan Loh Shaomin Liu Wei Zhou Jaka Sunarso 《International Journal of Hydrogen Energy》2018,43(32):15281-15305
Hydrogen is considered a fuel of the future due to its diversified supply and zero greenhouse gas emission. The application of advanced membrane technology for hydrogen separation within the larger hydrogen production process context can substitute the use of more expensive and energy intensive cryogenic distillation and pressure swing adsorption technologies. This review overviews the basic aspects and progresses in perovskite-based proton conducting hydrogen separation membranes. Different configurations such as symmetric, asymmetric, hollow fiber, and surface modified perovskite membranes with various compositions are discussed and summarized. The challenges and future directions of such membranes are also elaborated. 相似文献