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排序方式: 共有126条查询结果,搜索用时 250 毫秒
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Magno Aparecido G. Trindade Glaucia Maria da Silva Valdir Souza Ferreira 《Microchemical Journal》2005,81(2):209-216
This work presents an electroanalytical methodology developed for square-wave voltammetry based in the electrochemical reduction in hanging mercury drop electrode (HMDE), which is simple, fast, reliable and sensitive for determination of moxifloxacin (MOXI) in tablets and spiked urine human samples. The support electrolyte that provided a more defined and intense peak current for MOXI determination was the phosphate buffer 0.04 mol l− 1 pH 8.0. In the best-optimized conditions the drug presented an only peak of reduction at − 1.38 V vs. Ag/AgCl, using an Eacc. of − 0.30 V. An LOD of 0.44 and 3.20 ng ml− 1 and an LOQ of 1.46 and 10.60 ng ml− 1 were found for the pure standard of moxifloxacin and in the presence of matrix, respectively. A good recovery was obtained for assay spiked urine samples and a good quantification of MOXI was achieved in a commercial formulation. The methodology proposed was more sensitive than the spectrofluorimetric and spectrophotometric method with precision and accuracy equivalent. 相似文献
3.
H. Lawrence Clever 《Monatshefte für Chemie / Chemical Monthly》2003,134(5):745-750
Summary. There are more than 150 papers that report on the solubility of the four chloromethanes in water. Volume 62 of the Solubility
Data Series compiles and evaluates the papers concerned with the liquid–liquid solubility of the chloromethanes with water.
A similar evaluation has not been carried out for the vapor–liquid solubility at a partial pressure up to the saturation vapor
pressure of the four chloromethanes. This paper uses the liquid–liquid evaluated solubility values to calculate vapor–liquid
Henry’s constants. They are compared with a compilation of Henry’s constants with good agreements between the calculated constants and the median of the compiled constants. It is believed
that the calculated constants are a reliable set of values to use for the vapor–liquid solubility of the chloromethanes in
water.
E-mail: hlclever@worldnet.att.net
Received October 11, 2002; accepted October 22, 2002
Published online April 24, 2003
RID="a"
ID="a" Dedicated to Prof. Dr. Heinz Gamsj?ger on the occasion of his 70th birthday 相似文献
4.
Renato Fernandes Galdiano Jr. Eliana Gertrudes de Macedo Lemos Ricardo Tadeu de Faria Wagner Aparecido Vendrame 《Applied biochemistry and biotechnology》2014,172(5):2521-2529
Vitrification, a simple, fast, and recommended cryopreservation method for orchid germplasm conservation, was evaluated for Dendrobium hybrid “Dong Yai” mature seeds. The genetic stability of regenerated seedlings was also evaluated using flow cytometry. Mature seeds from this hybrid were submitted to plant vitrification solution (PVS2) for 0, 0.5, 1, 2, 3, 4, 5, or 6 h at 0 °C. Subsequently, they were plunged into liquid nitrogen (LN) at ?196 °C for 1 h and recovered in half-strength Murashige and Skoog culture medium (1/2 MS), and seed germination was evaluated after 30 days. Seeds directly submitted to LN did not germinate after cryopreservation. Seeds treated with PVS2 between 1 and 3 h presented the best germination (between 51 and 58 %), although longer exposure to PVS2 returned moderated germination (39 %). Germinated seeds were further subcultured in P-723 culture medium and developed whole seedlings in vitro after 180 days, with no abnormal characteristics, diseases, or nutritional deficiencies. Seedlings were successfully acclimatized under greenhouse conditions with over 80 % survival. Flow cytometry analysis revealed no chromosomal changes on vitrified seedlings, as well as seedlings germinated from the control treatment (direct exposure to LN). These findings indicate that vitrification is a feasible and safe germplasm cryopreservation method for commercial Dendrobium orchid hybrid conservation. 相似文献
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Kobelnik Marcelo Valentin Leonardo Antônio Valentin Clever Aparecido Lavoie Fernando Luiz da Silva Jefferson Lins Ribeiro Clóvis Augusto 《Journal of Thermal Analysis and Calorimetry》2022,147(21):11739-11745
Journal of Thermal Analysis and Calorimetry - Asphalt emulsion is a versatile product that can be used for different waterproofing applications in civil construction and highway constructions.... 相似文献
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Magno Aparecido Gonçalves Trindade Maria Valnice Boldrin Zanoni Frank‐Michael Matysik 《Electroanalysis》2010,22(9):955-962
This paper describes an analytical method using high‐performance liquid chromatographic (HPLC) separation coupled with electrochemical detection to detect three dyes, Solvent Blue 14 (SB‐14), Solvent Blue 35 (SB‐35) and Solvent Red 24 (SR‐24). The dyes were eluted and separated using a reversed‐phase column (C‐8) under isocratic elution with the mobile phase containing a mixture of acetonitrile/ammonium acetate (5.0 mmol L?1) at the ratio of 75 : 25 (v/v). Two sample pretreatment methods were tested and successfully applied to quantify SB14, SB‐35 and SR‐24 dyes in gasoline samples. The proposed method was simple, fast and suitable to detect and quantify marker dyes in gasoline sample at low concentration. 相似文献
10.
Ademir Aparecido Constantino Dario Landa-Silva Everton Luiz de Melo Candido Ferreira Xavier de Mendonça Douglas Baroni Rizzato Wesley Romão 《Annals of Operations Research》2014,218(1):165-183
This paper tackles a Nurse Scheduling Problem which consists of generating work schedules for a set of nurses while considering their shift preferences and other requirements. The objective is to maximize the satisfaction of nurses’ preferences and minimize the violation of soft constraints. This paper presents a new deterministic heuristic algorithm, called MAPA (multi-assignment problem-based algorithm), which is based on successive resolutions of the assignment problem. The algorithm has two phases: a constructive phase and an improvement phase. The constructive phase builds a full schedule by solving successive assignment problems, one for each day in the planning period. The improvement phase uses a couple of procedures that re-solve assignment problems to produce a better schedule. Given the deterministic nature of this algorithm, the same schedule is obtained each time that the algorithm is applied to the same problem instance. The performance of MAPA is benchmarked against published results for almost 250,000 instances from the NSPLib dataset. In most cases, particularly on large instances of the problem, the results produced by MAPA are better when compared to best-known solutions from the literature. The experiments reported here also show that the MAPA algorithm finds more feasible solutions compared with other algorithms in the literature, which suggest that this proposed approach is effective and robust. 相似文献