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1.
Animals (Basel) ; 14(14)2024 Jul 09.
Artículo en Inglés | MEDLINE | ID: mdl-39061490

RESUMEN

Since pig vocalization is an important indicator of monitoring pig conditions, pig vocalization detection and recognition using deep learning play a crucial role in the management and welfare of modern pig livestock farming. However, collecting pig sound data for deep learning model training takes time and effort. Acknowledging the challenges of collecting pig sound data for model training, this study introduces a deep convolutional neural network (DCNN) architecture for pig vocalization and non-vocalization classification with a real pig farm dataset. Various audio feature extraction methods were evaluated individually to compare the performance differences, including Mel-frequency cepstral coefficients (MFCC), Mel-spectrogram, Chroma, and Tonnetz. This study proposes a novel feature extraction method called Mixed-MMCT to improve the classification accuracy by integrating MFCC, Mel-spectrogram, Chroma, and Tonnetz features. These feature extraction methods were applied to extract relevant features from the pig sound dataset for input into a deep learning network. For the experiment, three datasets were collected from three actual pig farms: Nias, Gimje, and Jeongeup. Each dataset consists of 4000 WAV files (2000 pig vocalization and 2000 pig non-vocalization) with a duration of three seconds. Various audio data augmentation techniques are utilized in the training set to improve the model performance and generalization, including pitch-shifting, time-shifting, time-stretching, and background-noising. In this study, the performance of the predictive deep learning model was assessed using the k-fold cross-validation (k = 5) technique on each dataset. By conducting rigorous experiments, Mixed-MMCT showed superior accuracy on Nias, Gimje, and Jeongeup, with rates of 99.50%, 99.56%, and 99.67%, respectively. Robustness experiments were performed to prove the effectiveness of the model by using two farm datasets as a training set and a farm as a testing set. The average performance of the Mixed-MMCT in terms of accuracy, precision, recall, and F1-score reached rates of 95.67%, 96.25%, 95.68%, and 95.96%, respectively. All results demonstrate that the proposed Mixed-MMCT feature extraction method outperforms other methods regarding pig vocalization and non-vocalization classification in real pig livestock farming.

2.
J Anim Sci Technol ; 64(3): 564-573, 2022 May.
Artículo en Inglés | MEDLINE | ID: mdl-35709125

RESUMEN

In this study, considering the difficulties for all farms to convert farm styles to animal welfare-based housing, an experiment was performed to observe the changes in the behavior and welfare of sows when the slat floor was changed to a collective breeding ground. Twenty-eight sows used in this study were between the second and fifth parities to minimize the influence of parity. Using a flats floor cover, the flattening rates were treated as 0%, 20%, 30%, 40%, and 50%. Data collection was the behavior of sows visually observed using a camera (e.g., standing, lying, fighting and excessive biting behaviors, and abnormal behaviors) and the animal welfare level measured through field visits. Lying behavior was found to be higher (p < 0.01) as the flattening rate increased, and sows lying on the slatted cover also increased as the flattening rate increased (p < 0.01). Fighting behavior wasincreased when the flattening rate was increased to 20%, and chewing behavior was increased (p < 0.05) as the flattening rate increased. The animal welfare level of sows, 'good feeding', it was found that all treatment groups for body condition score and water were good at 100 (p < 0.05). 'Good housing' was the maximum value (100) in each treatment group. As the percentage of floor increased, the minimum good housing was increased from 78 in 0% flattening rate to 96 in 50% flattening rate. The maximum (100) 'good health' was achieved in the 0% and 20% flattening rates, and it was 98, 98, and 99 in the 30%, 50%, and 40% flattening rate, respectively. 'Appropriate behavior' score was significantly lower than that of other paremeters, but when the flattening ratio was 0% and 20%, the maximum and minimum values were 10. At 40% and 50%, the maximum values were 39 and 49, respectively, and the minimum values were analyzed as 19 for both 40% and 50%. These results will be used as basic data about sow welfare for farmers to successfully transition to group housing and flat floors.

3.
J Anim Sci Technol ; 61(3): 147-153, 2019 May.
Artículo en Inglés | MEDLINE | ID: mdl-31333871

RESUMEN

A goal for swine farming is the improvement in the number of live-born and weaned piglets per sow. Hence, the effect of parities should consider the correlation between the component traits of reproductive performance, weaning, and duration. Sows were housed in farrowing pens (W 2.2 × D 1.8 × H 1.2 m) on a partially slatted plastic floor. Twenty sows used in this study were between the first and sixth parity in gilts (P1), parity 2-5 (P3), and parity 6-9 (P6). Data collection by parity was classified into three categories: (1) reproduction performance (gestation length, total number of piglets born, number of piglets live born, number of piglets stillborn, total piglet birth weight; (2) weaning traits (weaning period, number of piglets weaning, total piglets weaning weight); (3) duration traits (farrowing duration, placenta expulsion duration, time from last piglet to first placenta, average birth interval, and tail wagging behavior). Gestation length was higher in P6 than P1 and P3 of different parity sows. The maximum value in P1 and P3 was 117 days, but the median value in P6 was 117 days (p < 0.05). The total number of piglets born (p = 0.113), number of piglets live born (p = 0.118), number of still piglets born (p = 0.151), and total piglet birth weight (p = 0.117) were not affected by parity. The number of live piglets was higher than the other parities by an average of 15.6 ± 2.1 in P1. The duration of farrowing was the lowest at 22.2 min in P6, but the maximum value was 42.2 min more than other parities (p = 0.355). Weaning traits of sows also did not differ significantly (p > 0.05), but the weaning period from P1 was lower than that of the other parities (p = 0.170). The number of piglets weaned was 10 heads on average in P1, P3, and P6 (p < 0.05). However, the mean values of the total piglet weaning weight (p = 0.377) of P6 (62.0 10.4 kg) were higher than those of P1 (54.9 10.2 kg) and P3 (58.4 13.6 kg). The placenta expulsion duration was higher in P6 than that in P1 and P3 (p = 0.447). The time from the last piglet to first placenta was be lower in P3 than that of the other parities (p = 0.206). The average birth interval was higher in P3 than that of the other parities (p = 0.156). Tail wagging (count) behavior was higher in P6 than in the other parities (p = 0.065). The data showed that the reproduction performance, total piglets born, and weight were higher in the gilts group, and higher in the weaning trait than that in the P6 group. This study examined the relationship between reproductive performance, birth interval and tail motion according to sow parity. Regarding duration, farrowing duration was lower in P6 than that in the other parities, but placenta expulsion and tail wagging were higher in P6 than in the other parities. Therefore, it is possible that the results from these sows could be used as basic data for effective farm management.

4.
Genes Genomics ; 40(12): 1373-1382, 2018 12.
Artículo en Inglés | MEDLINE | ID: mdl-30168091

RESUMEN

Hanwoo and Chikso are classified as Korean native cattle breeds that are currently registered with the Food and Agriculture Organization. However, there is still a lack of genomic studies to compare Hanwoo to Chikso populations. The objective of this study was to perform genome-wide analysis of Hanwoo and Chikso populations, investigating the genetic relationships between these two populations. We genotyped a total of 319 cattle including 214 Hanwoo and 105 Chikso sampled from Gangwon Province Livestock Technology Research Institute, using the Illumina Bovine SNP50K Beadchip. After performing quality control on the initially generated datasets, we assessed linkage disequilibrium patterns for all the possible SNP pairs within 1 Mb apart. Overall, average r2 values in Hanwoo (0.048) were lower than Chikso (0.074) population. The genetic relationship between the populations was further assured by the principal component analysis, exhibiting clear clusters in each of the Hanwoo and Chikso populations, respectively. Overall heterozygosity for Hanwoo (0.359) was slightly higher than Chikso (0.345) and inbreeding coefficient was also a bit higher in Hanwoo (- 0.015) than Chikso (- 0.035). The average FST value was 0.036 between Hanwoo and Chikso, indicating little genetic differentiation between those two breeds. Furthermore, we found potential selection signatures including LRP1B and NTRK2 genes that might be implicated with meat and reproductive traits in cattle. In this study, the results showed that both Hanwoo and Chikso populations were not under severe level of inbreeding. Although the principal component analysis exhibited clear clusters in each of the populations, we did not see any clear evidence that those two populations are highly differentiated each other.


Asunto(s)
Bovinos/genética , Estudio de Asociación del Genoma Completo , Receptor trkB/genética , Receptores de LDL/genética , Animales , Diferenciación Celular/genética , Genotipo , Técnicas de Genotipaje , Heterocigoto , Polimorfismo de Nucleótido Simple/genética , Análisis de Componente Principal
5.
Gene ; 589(1): 36-42, 2016 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-27188257

RESUMEN

Hanwoo is an indigenous Korean beef cattle breed, and it shared an ancestor with Yanbian cattle that are found in the Northeast provinces in China until the last century. During recent decades, those cattle breeds experienced different selection pressures. Here, we present genome-wide copy number variations (CNVs) by comparing Hanwoo and Yanbian cattle sequencing data. We used ~3.12 and ~3.07 billion sequence reads from Hanwoo and Yanbian cattle, respectively. A total of 901 putative CNV regions (CNVRs) were identified throughout the genome, representing 5,513,340bp. This is a smaller number than has been reported in previous studies, indicating that Hanwoo are genetically close to Yanbian cattle. Of the CNVRs, 53.2% and 46.8% were found to be gains and losses in Hanwoo. Potential functional roles of each CNVR were assessed by annotating all CNVRs and gene ontology (GO) enrichment analysis. We found that 278 CNVRs overlapped with cattle gene-sets (genic-CNVRs) that could be promising candidates to account for economically important traits in cattle. The enrichment analysis indicated that genes were significantly over-represented in GO terms, including developmental process, multicellular organismal process, reproduction, and response to stimulus. These results provide a valuable genomic resource for determining how CNVs are associated with cattle traits.


Asunto(s)
Variaciones en el Número de Copia de ADN , Genoma , Anotación de Secuencia Molecular , Carácter Cuantitativo Heredable , Selección Genética , Animales , Cruzamiento , Bovinos , China , Mapeo Cromosómico , Ontología de Genes , Secuenciación de Nucleótidos de Alto Rendimiento , Masculino , Análisis de Secuencia por Matrices de Oligonucleótidos , Fenotipo , Polimorfismo de Nucleótido Simple , República de Corea
6.
J Ethnopharmacol ; 149(1): 254-62, 2013 Aug 26.
Artículo en Inglés | MEDLINE | ID: mdl-23810843

RESUMEN

ETHNOPHARMACOLOGICAL RELEVANCE: Artemisia princeps Pampanini (Asteraceae) is used as a traditional medicine to immune function-related diseases, such as dysmenorrhea, inflammation, cancer, and ulcers. AIM OF THE STUDY: The purpose of this study is to evaluate the immunostimulatory effects of the hot water extract from the leaves of Artemisia princeps Pampanini (WAPP) in recombinant interferon-γ (rIFN-γ)-primed RAW 264.7 macrophages and in cyclophosphamide (20mg/kg, i.p.)-induced immunosuppressed Sprague-Dawley rats. MATERIALS AND METHODS: RAW 264.7 macrophages were treated with WAPP and production and expressions of nitric oxide (NO) and tumor necrosis factor-α (TNF-α) via nuclear factor-κB (NF-κB) were detected by immunoassay, western blot, qRT-PCR and reporter gene assay. In addition, in vivo immunomodulatory activity was studied by cyclophosphamide-induced myelosuppression in rats. RESULTS: In rIFN-γ-primed RAW 264.7 macrophages, pretreatment with WAPP increased the productions of nitric oxide (NO) and tumor necrosis factor-α (TNF-α),and increased the expressions of inducible nitric oxide synthase (iNOS) at the protein level and of iNOS and TNF-α at the mRNA level. Molecular data revealed that WAPP upregulated the transcriptional activity and translocation of nuclear factor-κB (NF-κB) by activating inhibitory kappa B-α (IκB-α) degradation and phosphorylation. Furthermore, WAPP upregulated the phosphorylations of p38 MAP kinase, c-Jun NH2-terminal kinase (JNK), and extracellular signal-regulated kinase 1/2 (ERK1/2). In cycloheximide-induced immunosuppressed rats, pretreatment with WAPP (100, 200, or 400mg/kg, p.o.) increased the serum levels of albumin and globulin, and reduced immobility times. CONCLUSION: Our results suggest that upregulations of the expressions of iNOS and TNF-α via the activations of NF-κB and MAPK are responsible for the immunostimulatory effects of WAPP.


Asunto(s)
Adyuvantes Inmunológicos/farmacología , Artemisia/química , Etnofarmacología , Medicina Tradicional Coreana , Extractos Vegetales/farmacología , Adyuvantes Inmunológicos/aislamiento & purificación , Animales , Técnicas de Cultivo de Célula , Línea Celular , Calor , Macrófagos/efectos de los fármacos , Macrófagos/inmunología , Ratones , Óxido Nítrico/biosíntesis , Óxido Nítrico/inmunología , Extractos Vegetales/aislamiento & purificación , Hojas de la Planta/química , Ratas , Ratas Sprague-Dawley , República de Corea , Natación , Factor de Necrosis Tumoral alfa/biosíntesis , Factor de Necrosis Tumoral alfa/inmunología , Agua/química
7.
J Am Chem Soc ; 135(6): 2207-12, 2013 Feb 13.
Artículo en Inglés | MEDLINE | ID: mdl-23363295

RESUMEN

This work explores the formation of well-defined molecular p-n junctions in solution-processed self-assembled heterojunction solar cells using dodecyloxy-substituted contorted hexabenzocoronene (12-c-HBC) as a donor material and phenyl-C(70)-butyric acid methyl ester (PC(70)BM) as an acceptor. We find that the contorted 12-c-HBC molecules effectively assemble in solution to form a nested structure with the ball-shaped PC(70)BM. The result is a self-assembled molecular-scale p-n junction. When this well-defined p-n junction is embedded in active films, we can make efficient self-assembled solar cells with minimal amounts of donor material relative to the acceptor. The power conversion efficiency is drastically enhanced by the mode of donor and acceptor assembly within the film.

8.
Angew Chem Int Ed Engl ; 51(34): 8594-7, 2012 Aug 20.
Artículo en Inglés | MEDLINE | ID: mdl-22807341

RESUMEN

"Ball and socket" motif: The contorted dibenzotetrathienocoronene (6-DBTTC) forms a complex with the C(70) fullerene PC(70) BM embedded in an amorphous phase of PC(70) BM. The materials are processable into organic solar cells in solution. The power conversion efficiency is maximal when there is a 1:2 molar ratio of 6-DBTTC to PC(70) BM. Formation of the supramolecular complex directly affects charge separation in the active layer.


Asunto(s)
Fulerenos/química , Compuestos Policíclicos/química , Energía Solar , Semiconductores
9.
Langmuir ; 27(17): 11265-71, 2011 Sep 06.
Artículo en Inglés | MEDLINE | ID: mdl-21774546

RESUMEN

The ability to laminate and delaminate top metal contacts during the processing and testing of inverted polymer solar cells has led us to uncover the peculiar dependence of their open-circuit voltage (V(oc)) on the annealing sequence. Specifically, thermally annealing inverted polymer solar cells having bulk-heterojunction photoactive layers after top electrode deposition above 100 °C leads to lower V(oc) compared to analogous devices with unannealed photoactive layers or photoactive layers that have been annealed prior to metal electrode deposition. This reduction in V(oc), however, can be reversed when the top electrodes are replaced. This observation is thus a strong indication that such changes in V(oc) with annealing sequence are manifestations of changes at the top electrode-photoactive layer interface, and not structural changes in the bulk of the photoactive layer. Electronic characterization conducted on the photoactive layers and metal contacts after dissection of the polymer solar cells via delamination suggests the reduction of V(oc) on thermal annealing in the presence of the metal top contacts to stem from an interfacial chemical reaction between the photoactive layers and the metal electrodes. This chemically generated interfacial layer is removed upon electrode delamination, effectively reverting the V(oc) to its original value prior to thermal annealing when the top electrodes are replaced.

10.
Chem Commun (Camb) ; 47(27): 7617-9, 2011 Jul 21.
Artículo en Inglés | MEDLINE | ID: mdl-21660352

RESUMEN

Amide functionalized anthradithiophenes (ADTs) play active acceptor roles in polymer bulk-heterojunction solar cells. The first separation of ADT isomers is reported, and the regiochemistry of the ADT has significant impact on crystal packing and solar cell performance. Cell efficiency up to 0.80%, due in large part to high open-circuit voltage (V(OC) > 1.0 V), is achieved in bulk-heterojunction solar cells comprising syn-ADT and poly(3-hexylthiophene).

11.
Langmuir ; 26(7): 5072-6, 2010 Apr 06.
Artículo en Inglés | MEDLINE | ID: mdl-20350010

RESUMEN

Long-term stability of intermediate liquid crystal pretilt angles on a poly(dimethylsiloxane) (PDMS) ultrathin film grafted onto a surface was realized simply and easily via low-energy ion beam (IB) treatment. The composition and surface energy of the thin film could be controlled by varying the low-energy IB treatment. This treatment results in the permanent chemical modification of the film surface, converting it from organic PDMS to a mixed layer of organic PDMS and inorganic silica. The partial transformation of a PDMS surface gives rise to the control of the pretilt angle via the formation of the inhomogeneous surface and the stabilization of the pretilt angle via the cross-linking reaction of broken chemical bonds through IB irradiation. As a result, a continuous variation of pretilt angles that maintained their initial value with long-term stability was obtained. Thus, the unique chemical transformation of the PDMS surface using IB treatment may allow for the production of durable intermediate liquid crystal pretilt angles.


Asunto(s)
Dimetilpolisiloxanos/química , Cristales Líquidos/química , Membranas Artificiales , Dióxido de Silicio/química , Propiedades de Superficie
13.
Langmuir ; 22(21): 9018-22, 2006 Oct 10.
Artículo en Inglés | MEDLINE | ID: mdl-17014148

RESUMEN

Here, we introduce a nanopatternable hydrophilic composite elastomer highly desirable for both nanostructure patterning via solvent-assisted micromolding (SAMIM) and microcontact printing of polar inks. This composite precursor is prepared by blending two UV-curable materials, Norland Optical Adhesives (NOA) 63 and poly(ethylene glycol) diacrylate (PEGDA), in an appropriate ratio; upon UV polymerization, a nanopatternable elastomer with preferential permeability both to aqueous and organic solvent is fabricated. Using this composite mold, nanoscale SAMIM of poly(4-vinylpyridine) (P4VP) and microcontact printing of a polar biomolecule, bovine serum albumin (BSA), was successfully demonstrated, paving the way for facile and efficient reproduction of various nanopatterns and a biomolecule-printed array platform.


Asunto(s)
Modelos Químicos , Polímeros/química , Agua/química , Elastómeros , Microscopía Electrónica de Rastreo , Polietilenglicoles/química
14.
Langmuir ; 21(24): 11079-84, 2005 Nov 22.
Artículo en Inglés | MEDLINE | ID: mdl-16285774

RESUMEN

The mechanism of liquid crystal (LC) alignment has been investigated during the last few decades for inorganic materials as well as for organic materials; however, it has not been clearly confirmed for some alignment materials. Inorganic alignment materials such as amorphous silicon oxide (a-SiOx) and hydrogenated amorphous silicon oxide (a-SiOx:H) are deposited on indium tin oxide (ITO) films on glass by reactive sputtering deposition. After deposition, the inorganic alignment materials are irradiated using an Ar+ ion beam (IB) for LC alignment. On the basis of the experimental results, a-SiOx films deposited by the sputtering do not align the LC, but a-SiOx:H films treated with varying IB energies, IB incident angles, IB doses, and IB irradiation times have excellent alignment properties and electrooptical properties, identical to those of polyimide (PI). These results imply that inorganic alignment layers irradiated by IB can be adopted as an LC alignment layer instead of rubbed PI. Additionally, hydrogen plays an important role in LC alignment because of the difference in alignment properties between a-SiOx films and a-SiOx:H films. We investigate the mechanism of IB-treated inorganic alignment layers and suggest that LCs are aligned by chemical effects, such as van der Waals interaction, more than by physical effects, such as morphology effects, in the inorganic alignment layer irradiated by IB.

15.
J Chromatogr A ; 1079(1-2): 266-73, 2005 Jun 24.
Artículo en Inglés | MEDLINE | ID: mdl-16038313

RESUMEN

A method based on the presence of a dynamic pH junction within the capillary to induce band narrowing for enhanced detection sensitivity for some peptides is presented. This technique is predicated on a sharp reduction in an analyte's migration velocity following a reversal of its electrophoretic direction from the acidic sample zone to the basic BGS zone. Larger-than-usual injection volumes of samples in relatively high-conductivity matrices were enabled, without degrading peak shape, resolution and efficiency. The size of the original sample plug was reduced by as much as 38-fold, and improvement in detector response in terms of peak height by as much as 124-fold was obtained. The effects of pH and concentration of the sample matrix, and the length of sample injection on the efficiency of the technique are discussed.


Asunto(s)
Angiotensina II/aislamiento & purificación , Angiotensina I/aislamiento & purificación , Electroforesis Capilar/métodos , Concentración de Iones de Hidrógeno , Tampones (Química) , Análisis de Inyección de Flujo , Péptidos/aislamiento & purificación
16.
J Chromatogr A ; 1018(2): 251-6, 2003 Nov 14.
Artículo en Inglés | MEDLINE | ID: mdl-14620575

RESUMEN

To improve detection sensitivity of cationic analytes, a dynamic pH junction technique was examined. Dynamic pH junction is an on-line focusing method in capillary electrophoresis (CE) based on the difference in the analyte's mobility between the background electrolyte (BGE) and sample matrix. The effects of pH values and concentrations of the BGE and the sample matrix on dynamic pH junction were examined. Optimization of analyte focusing resulted in enhanced detection responses of about 100-160-fold in terms of peak heights for some anilines in comparison to conventional injections. In particular, the concentration limits of detection (LOD) (S/N = 3) for the test anilines obtained with dynamic pH junction were from 1.9 to 3.7 ppb with UV detection without any pretreatment procedure.


Asunto(s)
Electroforesis Capilar/métodos , Concentración de Iones de Hidrógeno , Cationes
17.
Anal Chem ; 75(16): 3986-93, 2003 Aug 15.
Artículo en Inglés | MEDLINE | ID: mdl-14632109

RESUMEN

Dynamic pH junction is an on-line preconcentration method in capillary electrophoresis (CE) based on electrokinetic focusing of weakly ionic analytes with in large sample volumes in a multisection electrolyte system. In this report, experiments and computer simulations were performed to gain a better insight of the analyte focusing mechanism when a dynamic pH junction was used. A computer program, SIMUL, was used to simulate the band-narrowing process of a group for phenol derivatives under optimized buffer conditions, which were compared with experimental results. Computer simulations revealed the formation of a sharp moving pH boundary within the sample zone causing efficient focusing of long plugs of weakly acidic analytes based on their pKa. These studies offered useful information for understanding the band-narrowing process by control of the depth and lifetime of the moving pH boundary as a function of analyte pKa, sample pH, and injection length. The change in pH of the sample within the capillary was also estimated by measuring the absorbances of an analyte at two different wave-lengths. Optimization of analyte focusing resulted in enhanced detection responses of about 60-450-fold in terms of peak heights for some phenol derivatives' relation to conventional injections. Dynamic pH junction represents a novel approach to control band dispersion (peak width) and selectivity (mobility) of specific analytes for high-resolution CE separations.

18.
J Pharm Biomed Anal ; 30(6): 1625-43, 2003 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-12485708

RESUMEN

This review provides an overview as well as a practical understanding of on-line sample concentration techniques in micellar electrokinetic chromatography (MEKC). MEKC as well as other capillary electrophoretic modes suffer from low concentration sensitivity due to minute sample volume and limited optical pathlength for on-capillary photometric detection. Two on-line sample preconcentration techniques, sample stacking and sweeping are known to be effective techniques for enhancement of the concentration sensitivity in MEKC. Sample stacking occurs as ions cross a boundary that separates regions of the high electric field sample zone and the low electric field background solution zone. The difference in migration velocity of pseudostationary phases within the two zones is the key to achieving the focusing effect. Sweeping is defined as the picking and accumulating of analytes by the pseudostationary phase that penetrates the sample zone devoid of pseudostationary phase. In this review, several examples of the sample stacking and sweeping under different experimental conditions are given, besides many references to applications.


Asunto(s)
Cromatografía Capilar Electrocinética Micelar/métodos , Preparaciones Farmacéuticas/análisis , Tecnología Farmacéutica/métodos
19.
J Pharm Biomed Anal ; 30(6): 1861-7, 2003 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-12485728

RESUMEN

Enantioselective separation of triadimenol, a component of systemic agricultural fungicide, by electrokinetic chromatography (EKC) using cyclodextrins (CDs) as chiral selectors was investigated. Both a neutral CD derivative, hydroxypropyl-gamma-CD (HP-gamma-CD), and an ionic one, heptakis-6-sulfato-beta-CD (HS-beta-CD), were employed as an additive in cyclodextrin-modified micellar electrokinetic chromatography (CD-MEKC) and as a chiral pseudostationary phase in CDEKC, respectively. In each system, four stereoisomeric peaks were completely or partially separated from each other. To enhance the detectability or the concentration sensitivity, on-line preconcentration techniques were applied to both EKC systems. Sweeping was used in the CD-MEKC system under an acidic condition, whereas stacking with a reverse migrating pseudostationary phase (SRMP) in the CDEKC system. Around 10-fold increase in the detection sensitivity for each peak was attained with both sweeping and SRMP systems. Good repeatabilities in the migration time, corrected peak area, and peak height were recognized in terms of the relative standard deviation. The limit of detection for each peak in the SRMP-CDEKC system, calculated from the calibration curve, was found to be 0.8-3.8 ppm.


Asunto(s)
Cromatografía Capilar Electrocinética Micelar/métodos , Ciclodextrinas/análisis , Triazoles/análisis , Ciclodextrinas/química , Estereoisomerismo , Triazoles/química
20.
J Chromatogr A ; 979(1-2): 131-6, 2002 Dec 06.
Artículo en Inglés | MEDLINE | ID: mdl-12498241

RESUMEN

To improve the detection sensitivity of some aromatic carboxylic acids and naphthalenesulfonic acids, the use of ion-pair reagents was examined in sweeping micellar electrokinetic chromatography (MEKC) with an anionic sodium dodecyl sulfate (SDS) micelle. Tetraalkylammonium (TAA) salts were used as ion-pair reagents to improve the sweeping efficiency. The effects of the alkyl chain length of the TAA groups and the TAA salt concentration on sweeping were examined. Under optimized conditions, about 400-fold enhancement in detection sensitivity was obtained in terms of peak heights by addition of ion-pair reagents in sweeping MEKC. This value was about 10 times greater than that obtainable by the SDS micelle used alone.


Asunto(s)
Cromatografía Capilar Electrocinética Micelar/métodos , Indicadores y Reactivos/química , Ácidos Carboxílicos/análisis , Iones , Micelas , Naftalenosulfonatos/análisis , Sensibilidad y Especificidad
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