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排序方式: 共有889条查询结果,搜索用时 890 毫秒
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Hugo M. Campos Vladislav V. Kravchenko 《Mathematical Methods in the Applied Sciences》2020,43(16):9448-9454
The paper extends some well-known results for analytic functions onto solutions of the Vekua equation regarding the existence and construction of the Bergman kernel and of the corresponding Bergman projection operator. 相似文献
3.
Rapid and sensitive ultra‐high‐pressure liquid chromatography method for quantification of antichagasic benznidazole in plasma: application in a preclinical pharmacokinetic study 下载免费PDF全文
Marcelo Gomes Davanço Michel Leandro de Campos Rosângela Gonçalves Peccinini 《Biomedical chromatography : BMC》2015,29(7):1008-1015
Benznidazole (BNZ) and nifurtimox are the only drugs available for treating Chagas disease. In this work, we validated a bioanalytical method for the quantification of BNZ in plasma aimed at improving sensitivity and time of analysis compared with the assays already published. Furthermore, we demonstrated the application of the method in a preclinical pharmacokinetic study after administration of a single oral dose of BNZ in Wistar rats. A Waters® Acquity UHPLC system equipped with a UV–vis detector was employed. The method was established using an Acquity® UHPLC HSS SB C18 protected by an Acquity® UHPLC HSS SB C18 VanGuard guard column and detection at 324 nm. The mobile phase consisted of ultrapure water–acetonitrile (65:35), and elution was isocratic. The mobile phase flow rate was 0.55 mL/min, the volume of injection was 1 μL, and the run time was just 2 min. The samples were kept at 25°C until injection and the column at 45°C for the chromatographic separation. The sample preparation was performed by a rapid protein precipitation with acetonitrile. The linear concentration range was 0.15–20 µg/mL. The pharmacokinetic parameters of BNZ in rats were determined and the method was considered sensitive, fast and suitable for application in pharmacokinetic studies. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
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Carla Maria Mariano Fernandez Maurício Ferreira da Rosa Ana Claudia Aparecida Mariano Fernandez Wanessa de Campos Bortolucci Fabiana Borges Padilha Ferreira Giani Andrea Linde 《Natural product research》2020,34(5):731-735
AbstractThis study, was to evaluate the acaricidal effect of the essential oil (EO) and fractions (FR) obtained from Laurus nobilis leaves on Rhipicephalus (Boophilus) microplus. Eight fractions were obtained, however FR1: sabinene (37.83%), β-pinene (13.50%), 1,8-cineole (12.66%), α-pinene (12.56%) and FR8: α-terpineol (79.19%) were highlighted as to the larvicidal potential when submitted by Larval Packet Test. The EO was tested by the Adult Immersion Test, at concentrations of 200.00; 100.00 and 50.00?µL/mL caused mortality of engorged females, egg mass reduction and hatching inhibition. Two fractions are shown to be efficient in controlling larvae FR8 (LC50?=?0.13?µL/mL, LC99?=?0.51?µL/mL) and FR1 (LC50?=?0.20?µL/mL, LC99?=?0.56?µL/mL). The fractionation of EO was determinant to elucidate which compounds were responsible for the larvicidal potential. This study opens new perspectives to direct new bioassays with the compounds obtained in the fractionation, since they present high potential on cattle tick larvae. 相似文献
6.
Victor Hugo Infante Patricia Maria Maia Campos Maxim Darvin Silke Lohan Johannes Schleusener Sabine Schanzer Juergen Lademann Martina Meinke 《Photochemistry and photobiology》2023,99(1):176-183
This aim of this study was to evaluate the penetration depth, antioxidant capacity and the clinical efficacy of Melaleuca alternifolia pure essential oil and in a nanoemulsion to prevent skin photoaging. For this, 2% of pure essential oil or 2% of this essential oil in a nanoemulsion were vehiculated in a formulation. The skin penetration was evaluated using confocal Raman microspectroscopy. The radical protection factor was evaluated using electron paramagnetic resonance spectroscopy. For a clinical study, 40 male participants, aged 18–28 years, were enrolled, being divided into three groups: vehicle formulation, M. alternifolia pure essential oil and M. alternifolia Nanoemulsion. All the participants also received a sunscreen SPF 50 to use during the day. Before and after 90 days of study, skin hydrolipidics and morphological characteristics were performed by skin imaging and biophysical techniques. The nanoemulsion presented a lower antioxidant capacity and a higher penetration through the stratum corneum, reaching the viable epidermis, improving the stratum granulosum morphology. The groups presented an increase in the papillary depth, improving in the dermis echogenicity and the collagen fibers. Melaleuca alternifolia essential provides the potential to improve photoaged skin, being the application of nanoemulsion able to reach deeper skin layers. 相似文献
7.
Catalytic Borylation using an Air‐Stable Zinc Boryl Reagent: Systematic Access to Elusive Acylboranes 下载免费PDF全文
Dr. Jesús Campos Prof. Dr. Simon Aldridge 《Angewandte Chemie (International ed. in English)》2015,54(47):14159-14163
The use of borylzinc reagents in palladium‐catalyzed borylation chemistry is described (i.e. a boron analogue of the Negishi coupling), including a one‐pot bench‐top protocol using an air‐ and moisture‐stable bis(boryl)zinc reagent. The steric/electronic properties of the boryl fragment employed enable a systematic method for accessing acylboranes, a rare class of organoboron species with great potential in chemical synthesis. The reactions proceed under mild conditions, use inexpensive commercial sources of palladium, and demonstrate a remarkable functional‐group tolerance. 相似文献
8.
Jos J. Campos‐Gaxiola Susana P. Arredondo Rea Ramn Corral Higuera Herbert Hpfl Adriana Cruz Enríquez 《Acta Crystallographica. Section C, Structural Chemistry》2015,71(1):48-52
Two organic–inorganic hybrid compounds have been prepared by the combination of the 4‐[(E)‐2‐(pyridin‐1‐ium‐2‐yl)ethenyl]pyridinium cation with perhalometallate anions to give 4‐[(E)‐2‐(pyridin‐1‐ium‐2‐yl)ethenyl]pyridinium tetrachloridocobaltate(II), (C12H12N2)[CoCl4], (I), and 4‐[(E)‐2‐(pyridin‐1‐ium‐2‐yl)ethenyl]pyridinium tetrachloridozincate(II), (C12H12N2)[ZnCl4], (II). The compounds have been structurally characterized by single‐crystal X‐ray diffraction analysis, showing the formation of a three‐dimensional network through X—H...ClnM− (X = C, N+; n = 1, 2; M = CoII, ZnII) hydrogen‐bonding interactions and π–π stacking interactions. The title compounds were also characterized by FT–IR spectroscopy and thermogravimetric analysis (TGA). 相似文献
9.
Ana Elisa Ferreira Oliveira Arnaldo César Pereira Mayra Asevedo Campos de Resende Lucas Franco Ferreira 《Electroanalysis》2022,34(5):809-819
In this work, a silver/silver chloride ink is fabricated using two steps. First the silver ink is prepare using silver, nail polish and acetone. Then the silver ink is painted in a paper substrate and a silver chloride layer is deposited using a bleach solution. The result is the silver/silver chloride conductive ink. The silver ink is cheap ($2.49/g), well-dispersive and very easy to fabricate. The materials were characterized by SEM and XRD. The Ag ink showed the formation of a continuous network throughout the silver ink film with fewer agglomeration. The effective chlorination process was also observed in the Ag/AgCl characterization. Since the Ag/AgCl substrate will be used as a quasi-reference electrode, it is important to investigate the electrical properties. The Ag ink showed an average ohmic resistance of 2.27 Ω. The addition of the AgCl layer decreases the conductivity, as expected. In summary, the Ag/Ag/Cl ink developed is simple, well-dispersed, cheap and with good conductivity. Therefore, it can be used as a conductive ink in the fabrication of quasi-reference electrodes. 相似文献
10.
Novel extracellular polymeric substances produced by Cupriavidus necator IPT 027 grown on glucose and crude glycerol originated from biodiesel 下载免费PDF全文
The aim of this study was to evaluate the production and properties of novel extracellular polymeric substances (EPS) from glucose (EPS 1) and crude glycerol (CG) from castor beans oil (EPS 2). Cupriavidus necator IPT 027 cultivated with glucose and CG (35 °C, 150 rpm, 72 hr, pH 7, shaker) produced approximately 1.60 ± 0.01 and 2.83 ± 0.02 g l?1 EPS, respectively, with high‐molecular weight (3.89 × 105 and 1.89 × 107 Da) and constituted of different functional groups such as uronic acid, monosaccharides (glucose, mannose, arabinose, and fucose) and primary amine group. The composition of the fermentable substrate influenced the melting temperature (221.11 and 230.18 °C), crystallinity (34.36% and 37.11%), degradation temperature (255.06 and 296.62 °C) and morphology. EPS showed pseudoplastic non‐Newtonian fluid behavior in the aqueous solutions, presenting potential applicability biotechnological and industrial mainly in food industry as emulsifiers and biosurfactants. This is the first study on the production and characterization of EPS obtained by C. necator IPT 027 in culture with glucose and CG. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献