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991.
Michael K. Hausmann Alina Hauser Gilberto Siqueira Rafael Libanori Signe Lin Vehusheia Simone Schuerle Tanja Zimmermann Andr R. Studart 《Small (Weinheim an der Bergstrasse, Germany)》2020,16(1)
Responsive materials with birefringent optical properties have been exploited for the manipulation of light in several modern electronic devices. While electrical fields are often utilized to achieve optical modulation, magnetic stimuli may offer an enticing complementary approach for controlling and manipulating light remotely. Here, the synthesis and characterization of magnetically responsive birefringent microparticles with unusual magneto‐optical properties are reported. These functional microparticles are prepared via a microfluidic emulsification process, in which water‐based droplets are generated in a flow‐focusing device and stretched into anisotropic shapes before conversion into particles via photopolymerization. Birefringence properties are achieved by aligning cellulose nanocrystals within the microparticles during droplet stretching, whereas magnetic responsiveness results from the addition of superparamagnetic nanoparticles to the initial droplet template. When suspended in a fluid, the microparticles can be controllably manipulated via an external magnetic field to result in unique magneto‐optical coupling effects. Using a remotely actuated magnetic field coupled to a polarized optical microscope, these microparticles can be employed to convert magnetic into optical signals or to estimate the viscosity of the suspending fluid through magnetically driven microrheology. 相似文献
992.
Rafael Lins Sergio Persival Proença C. Armando Duarte 《International journal for numerical methods in engineering》2019,119(12):1279-1306
This paper presents a new stress recovery technique for the generalized/extended finite element method (G/XFEM) and for the stable generalized FEM (SGFEM). The recovery procedure is based on a locally weighted L2 projection of raw stresses over element patches; the set of elements sharing a node. Such projection leads to a block-diagonal system of equations for the recovered stresses. The recovery procedure can be used with GFEM and SGFEM approximations based on any choice of elements and enrichment functions. Here, the focus is on low-order 2D approximations for linear elastic fracture problems. A procedure for computing recovered stresses at re-entrant corners of any internal angle is also presented. The proposed stress recovery technique is used to define a Zienkiewicz-Zhu (ZZ) a posteriori error estimator for the G/XFEM and the SGFEM. The accuracy, computational cost, and convergence rate of recovered stresses together with the quality of the ZZ estimator, including its effectivity index, are demonstrated in problems with smooth and singular solutions. 相似文献
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995.
D‐dimer levels in maintenance hemodialysis patients: High prevalence of positive values also in the group without predisposing diseases 下载免费PDF全文
Jakob Gubensek Matea Lolic Rafael Ponikvar Jadranka Buturovic‐Ponikvar 《Hemodialysis international. International Symposium on Home Hemodialysis》2016,20(2):198-203
We aimed to estimate the prevalence of elevated D‐dimer levels in all chronic hemodialysis patients and those without additional disease, and to identify factors associated with increased D‐dimer. In 167 chronic hemodialysis patients from our center, D‐dimer was measured before dialysis. The effects of age, C‐reactive protein (CRP), recent acute illness, vascular access, anticoagulation type, dialysis vintage, and chronic diseases, considered to predispose for increased D‐dimer levels, were analyzed. The median D‐dimer in the whole group was 966 (inter‐quartile range [IQR] 524–1947) μg/L and was positive (>500 μg/L) in 75% of cases. D‐dimer was positive in 91% of patients with acute illness, 76% of those with predisposing chronic diseases, but was still positive in 52% of patients without additional disease (i.e., acute illness or predisposing chronic diseases) – median D‐dimer was 538.5 (IQR 359–966) μg/L. D‐dimer was correlated to patients' age, but not dialysis vintage. In univariate analysis, the D‐dimer levels were significantly higher in patients with atrial fibrillation, ischemic heart disease, recent acute illness, increased CRP, dialyzed over a catheter, and on citrate anticoagulation. Multivariate logistic regression showed that only age >65 years (odds ratio [OR] 2.93), catheter (OR 4.86), and positive CRP (OR 4.07) were independently associated with positive D‐dimer at 500 μg/L cut‐off, while the significance of age disappeared at 2000 μg/L cut‐off. To conclude, the high prevalence of positive D‐dimer values even in hemodialysis patients without additional disease limits the use of D‐dimer for exclusion of thromboembolic diseases in hemodialysis patients. 相似文献
996.
The Shortening of MWNT‐SPION Hybrids by Steam Treatment Improves Their Magnetic Resonance Imaging Properties In Vitro and In Vivo 下载免费PDF全文
Laura Cabana Maxime Bourgognon Julie T.‐W. Wang Andrea Protti Rebecca Klippstein Rafael T. M. de Rosales Ajay M. Shah Josep Fontcuberta Ester Tobías‐Rossell Jane K. Sosabowski Khuloud T. Al‐Jamal Gerard Tobias 《Small (Weinheim an der Bergstrasse, Germany)》2016,12(21):2893-2905
Carbon nanotubes (CNTs) have been advocated as promising nanocarriers in the biomedical field. Their high surface area and needle‐like shape make these systems especially attractive for diagnostic and therapeutic applications. Biocompatibility, cell internalization, biodistribution, and pharmacokinetic profile have all been reported to be length dependent. In this study, further insights are gotten on the role that the length of CNTs plays when developing novel contrast agents for magnetic resonance imaging (MRI). Two samples of CNTs with different length distribution have been decorated with radio‐labeled iron oxide nanoparticles. Despite characterization of the prepared hybrids reveals a similar degree of loading and size of the nanoparticles for both samples, the use of short CNTs is found to enhance the MRI properties of the developed contrast agents both in vitro and in vivo compared to their long counterparts. 相似文献
997.
Al Rey C. Villagracia Andres Philip Mayol Aristotle T. Ubando Jose Bienvenido Manuel M. Biona Nelson B. ArboledaJr. Melanie Y. David Roy B. Tumlos Henry LeeJr. Ong Hui Lin Rafael A. Espiritu Alvin B. Culaba Hideaki Kasai 《Clean Technologies and Environmental Policy》2016,18(8):2441-2451
Algal biofuels serve as a promising alternative energy source for liquid fuels. However, one of the bottlenecks in the conversion of microalgae to biofuels is the drying process. A moisture content of at most 10 % is desired for algal biomass prior to oil extraction to maximise biofuel yield. Conventional means of drying results to longer drying time and uneven drying of algal biomass. This study investigated the drying characteristics of microwave for microalgae (Chlorella vulgaris). Three microwave intensity levels (300, 600, and 900 W) were considered to dry 10, 20, and 30 of algal mass. Page model gave a better fit on the moisture ratio with time of microwave drying than the exponential model. Furthermore, the specific energy requirement was computed, and a relationship was found between moisture ratio with power and mass. Fourier transform infrared spectroscopy results showed significant reduction of infrared signal intensities of the functional groups present in the algae after drying at higher microwave power level. It was concluded that the 20 W/g microwave drying setting gave a lower specific energy requirement with good quality of remaining high lipid content qualitatively. Furthermore, it was recommended to use gas chromatography mass spectroscopy to further quantify the algal lipids and other functional groups. 相似文献
998.
In Situ Engineering of the Electrode–Electrolyte Interface for Stabilized Overlithiated Cathodes 下载免费PDF全文
999.
Enhanced Open‐Circuit Voltage in Colloidal Quantum Dot Photovoltaics via Reactivity‐Controlled Solution‐Phase Ligand Exchange 下载免费PDF全文
Jea Woong Jo Jongmin Choi F. Pelayo García de Arquer Grant Walters Bin Sun Olivier Ouellette Junghwan Kim Andrew H. Proppe Rafael Quintero‐Bermudez James Fan Jixian Xu Chih Shan Tan Oleksandr Voznyy Edward H. Sargent 《Advanced materials (Deerfield Beach, Fla.)》2017,29(43)
The energy disorder that arises from colloidal quantum dot (CQD) polydispersity limits the open‐circuit voltage (VOC) and efficiency of CQD photovoltaics. This energy broadening is significantly deteriorated today during CQD ligand exchange and film assembly. Here, a new solution‐phase ligand exchange that, via judicious incorporation of reactivity‐engineered additives, provides improved monodispersity in final CQD films is reported. It has been found that increasing the concentration of the less reactive species prevents CQD fusion and etching. As a result, CQD solar cells with a VOC of 0.7 V (vs 0.61 V for the control) for CQD films with exciton peak at 1.28 eV and a power conversion efficiency of 10.9% (vs 10.1% for the control) is achieved. 相似文献
1000.
Simon Matoori Yinyin Bao Aaron Schmidt Eric J. Fischer Rafael Ochoa‐Sanchez Mlanie Tremblay Mariana M. Oliveira Christopher F. Rose Jean‐Christophe Leroux 《Small (Weinheim an der Bergstrasse, Germany)》2019,15(50)
Ammonia‐scavenging transmembrane pH‐gradient poly(styrene)‐b‐poly(ethylene oxide) polymersomes are investigated for the oral treatment and diagnosis of hyperammonemia, a condition associated with serious neurologic complications in patients with liver disease as well as in infants with urea cycle disorders. While these polymersomes are highly stable in simulated intestinal fluids at extreme bile salt and osmolality conditions, they unexpectedly do not reduce plasmatic ammonia levels in cirrhotic rats after oral dosing. Incubation in dietary fiber hydrogels mimicking the colonic environment suggests that the vesicles are probably destabilized during the dehydration of the intestinal chyme. The findings question the relevance of commonly used simulated intestinal fluids for studying vesicular stability. With the encapsulation of a pH‐sensitive dye in the polymersome core, the local pH increase upon ammonia influx could be exploited to assess the ammonia concentration in the plasma of healthy and cirrhotic rats as well as in other fluids. Due to its high sensitivity and selectivity, this polymersome‐based assay could prove useful in the monitoring of hyperammonemic patients and in other applications such as drug screening tests. 相似文献