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991.
Dynamic mode decomposition (DMD) is a new diagnostic technique in fluid mechanics which is growing in popularity. A powerful
analysis tool, it has great potential for measuring the spatial and temporal dynamics of coherent structures in experimental
fluid flows. To aid interpretation of experimental data, error-bars on the measured growth rates are needed. In this article,
we undertake a massively parallel error analysis of the DMD algorithm using synthetic waveforms that are shown to be representative
of the canonical instabilities observed in shear flows. We show that the waveform of the instability has a marked impact on
the error of the measured growth rate. Sawtooth and square waves may have an order of magnitude larger error than sine waves
under the same conditions. We also show that the effects of data quantity and quality are of critical importance in determining
the error in the growth or decay rate, and that the effect of the key parametric variables are modulated by the growth rate
itself. We further demonstrate methods by which ensemble and orthogonal data may be introduced to improve the noise response.
With regard for the important variables, precise measurement of the growth rates of instabilities may be supplemented with
an accurately estimated uncertainty. This opens many new possibilities for the measurement of coherent structure in shear
flows. 相似文献
992.
The feasibility of using high-power light-emitting diodes (LED) as a light source for high frame rate schlieren imaging is investigated. Continuous sequences of high-intensity light pulses are achieved by overdriving the LED with current pulses up to a factor of ten beyond its specifications. In comparison to commonly used pulsed light sources such as gas discharge lamps and pulsed lasers, the pulsed LED has several attractive advantages: the pulse-to-pulse intensity variation is on the same order of magnitude as the detector (camera) noise permitting quantitative intensity measurements. The LED??s narrow emission bandwidth reduces chromatic abberations, yet it is spectrally wide enough to prevent the appearance of speckle and diffraction effects in the images. Most importantly, the essentially lag-free light emission within tens of nanoseconds of the applied current pulse allows the LED to be operated at varying frequencies (i.e., asynchronously), which generally is not possible with neither lasers nor discharge lamps. The pulsed LED source, driven by a simple driver circuit, is demonstrated on two schlieren imaging setups. The first configuration visualizes the temporal evolution of shock structures and sound waves of an under-expanded jet that is impinging on a rigid surface at frame rates of 500?kHz to 1?MHz. In a second application, long sequences of several thousand high-resolution images are acquired on a free jet at a frame rate of 1?kHz. The low-intensity fluctuation and large sample number allow a reliable computation of two-point correlation data from the image sequences. 相似文献
993.
Crystallization of metallic nanoparticles on short DNA oligonucleotides in alkaline aqueous solution
González-Olvera Julio C. Mercader-Trejo Flora Ramos-López Edith Rodríguez-López Aarón Álvarez-López Alejandra Flores-Juárez Cyntia R. Herrera-Basurto Raúl 《Journal of nanoparticle research》2020,22(3):1-14
Journal of Nanoparticle Research - A series of nickel phosphide catalysts with adjustable Brønsted acid sites and Lewis acid sites has been prepared by liquid-phase method using... 相似文献
994.
995.
Alba L. Montoya Elisa G. Carvajal Uriel Ortega-Rodriguez Igor L. Estevao Roger A. Ashmus Sohan R. Jankuru Susana Portillo Cameron C. Ellis Colin D. Knight Julio Alonso-Padilla Luis Izquierdo Maria-Jesus Pinazo Joaquim Gascon Veronica Suarez Douglas M. Watts Iliana R. Malo Janine M. Ramsey Belkisyol Alarcn De Noya Oscar Noya Igor C. Almeida Katja Michael 《Molecules (Basel, Switzerland)》2022,27(17)
Chagas disease (CD) is caused by the parasite Trypanosoma cruzi and affects 6–7 million people worldwide. The diagnosis is still challenging, due to extensive parasite diversity encompassing seven genotypes (TcI-VI and Tcbat) with diverse ecoepidemiological, biological, and pathological traits. Chemotherapeutic intervention is usually effective but associated with severe adverse events. The development of safer, more effective therapies is hampered by the lack of biomarker(s) (BMKs) for the early assessment of therapeutic outcomes. The mammal-dwelling trypomastigote parasite stage expresses glycosylphosphatidylinositol-anchored mucins (tGPI-MUC), whose O-glycans are mostly branched with terminal, nonreducing α-galactopyranosyl (α-Gal) glycotopes. These are absent in humans, and thus highly immunogenic and inducers of specific CD anti-α-Gal antibodies. In search for α-Gal-based BMKs, here we describe the synthesis of neoglycoprotein NGP11b, comprised of a carrier protein decorated with the branched trisaccharide Galα(1,2)[Galα(1,6)]Galβ. By chemiluminescent immunoassay using sera/plasma from chronic CD (CCD) patients from Venezuela and Mexico and healthy controls, NGP11b exhibited sensitivity and specificity similar to that of tGPI-MUC from genotype TcI, predominant in those countries. Preliminary evaluation of CCD patients subjected to chemotherapy showed a significant reduction in anti-α-Gal antibody reactivity to NGP11b. Our data indicated that NGP11b is a potential BMK for diagnosis and treatment assessment in CCD patients. 相似文献
996.
Dr. Rajasekaran Ganesan Mansour A. Dughbaj Lisa Ramirez Steven Beringer Dr. Teshome L. Aboye Prof. Alexander Shekhtman Prof. Paul M. Beringer Prof. Julio A. Camarero 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(49):12702-12708
The search for novel antimicrobial agents to combat microbial pathogens is intensifying in response to the rapid development of drug resistance to current antibiotic therapeutics. Respiratory failure and septicemia are the leading causes of mortality among hospitalized patients. Here, the development of a novel engineered cyclotide with effective broad-spectrum antibacterial activity against several ESKAPE bacterial strains and clinical isolates is reported. The most active antibacterial cyclotide was extremely stable in serum, showed little hemolytic activity, and provided protection in vivo in a murine model of P. aeruginosa peritonitis. These results highlight the potential of the cyclotide scaffold for the development of novel antimicrobial therapeutic leads for the treatment of bacteremia. 相似文献
997.
Mohamed Bouri Julio C. Zuaznabar-Gardona Marta Novell Pascal Blondeau Francisco J. Andrade 《Electroanalysis》2021,33(1):81-89
A filter paper sputtered with a layer of Pt and subsequently coated with a Nafion® membrane is used as working electrode. The mixed potential of the Pt electrode allows the detection of H2O2 generated by the oxidation of galactose in the presence of the galactose oxidase enzyme. This provides a simple and mediator-free approach method. The system shows sensitivity values of −62.8±9.4 mV/decade of galactose in the range from 0.3 to 31.6 mM, well within the clinical relevant range. MnO2 nanoparticles were added to decrease the interference from ascorbic acid so that validation of the sensor in whole blood samples was performed with good recovery. 相似文献
998.
Jeniffer Torres-Vega Sergio Gmez-Alonso Jos Prez-Navarro Julio Alarcn-Enos Edgar Pastene-Navarrete 《Molecules (Basel, Switzerland)》2021,26(8)
Chemical profiling of Buddleja globosa was performed by high-performance liquid chromatography coupled to electrospray ionization (HPLC-DAD-ESI-IT/MS) and quadrupole time-of-flight high-resolution mass spectrometry (HPLC-ESI-QTOF/MS). The identification of 17 main phenolic compounds in B. globosa leaf extracts was achieved. Along with caffeoyl glucoside isomers, caffeoylshikimic acid and several verbascoside derivatives (β-hydroxyverbascoside and β-hydroxyisoverbascoside) were identified. Among flavonoid compounds, the presence of 6-hydroxyluteolin-7-O-glucoside, quercetin-3-O-glucoside, luteolin 7-O-glucoside, apigenin 7-O-glucoside was confirmed. Campneoside I, forsythoside B, lipedoside A and forsythoside A were identified along with verbascoside, isoverbascoside, eukovoside and martynoside. The isolation of two bioactive phenolic compounds verbascoside and forsythoside B from Buddleja globosa (Buddlejaceae) was successfully achieved by centrifugal partition chromatography (CPC). Both compounds were obtained in one-step using optimized CPC methodology with the two-phase solvent system comprising ethyl acetate-n-butanol-ethanol-water (0.25:0.75:0.1:1, v/v). Additionally, eight Natural Deep Eutectic Solvents (NADESs) were tested for the extraction of polyphenols and compared with 80% methanol. The contents of verbascoside and luteolin 7-O-glucoside after extraction with 80% methanol were 26.165 and 3.206 mg/g, respectively. Among the NADESs tested in this study, proline- citric acid (1:1) and choline chloride-1, 2- propanediol (1:2) were the most promising solvents. With these NADES, extraction yields for verbascoside and luteolin 7-O-glucoside were 51.045 and 4.387 mg/g, respectively. Taken together, the results of this study confirm that CPC enabled the fast isolation of bioactive polyphenols from B. globosa. NADESs displayed higher extraction efficiency of phenolic and therefore could be used as an ecofriendly alternative to classic organic solvents. 相似文献
999.
Doménech-Carbó Antonio del Hoyo-Meléndez Julio M. Labut Maria Doménech-Carbó María Teresa 《Journal of Solid State Electrochemistry》2021,25(12):2767-2776
Journal of Solid State Electrochemistry - An electrochemical study was conducted on a series of samples taken from the metal supports of ten coffin portraits and one funeral portrait from the... 相似文献
1000.