RESUMO
There are still many controversies in the surgical treatment of esophagogastric junction tumors in terms of surgical approach, cleaning range, and resection scope. The reason is the confusion about the scope of the esophagogastric junction. The previous domestic and foreign anatomy descriptions of this part are not enough to solve the current problems. Based on a large number of basic anatomy and clinical operations, this article proposes that the esophagogastric junction may be wrapped by a complete and separate esophagogastric junction membrane with independent anatomy other than infracardiac bursa. The structure of the transitional tissue, mainly from the distribution of submucosal veins, explained the relationship and significance of tissue transitional changes and clinical operations, and made a reasonable analysis of the current controversy based on the anatomical characteristics, which is worthy of further investigation.
Assuntos
Adenocarcinoma , Neoplasias Esofágicas , Neoplasias Gástricas , Neoplasias Esofágicas/cirurgia , Junção Esofagogástrica , Humanos , Neoplasias Gástricas/cirurgiaRESUMO
Fraud in milk and dairy products occurs when cow milk is added to sheep and goat milk for economic reasons. No reliable, selective, and sensitive method exists for quantifying the milk percentage of different species. This work reports the development and validation of a proteomics-based method for the qualitative detection and quantitative determination of cow, sheep, and goat milks in the raw materials used for dairy products. ß-Lactoglobulin was selected as the protein marker because it is a major protein in milk and whey powder. The tryptic peptides LSFNPTQLEEQCHI and LAFNPTQLEGQCHV were used as signature peptides for cow milk and for sheep and goat milks, respectively. The winged peptides LKALPMHIRLSFNPTQL*EEQCHI* and LKALPMHIRLAFNPTQL*EGQCHV* were designed and synthesized as internal standards. Validation of the method showed that it has good sensitivity, specificity, reproducibility, precision, and accuracy. This method is easily applicable in routine laboratory analysis without intensive proteomics background.
Assuntos
Leite/química , Proteômica , Animais , Bovinos , Feminino , Cabras , Reprodutibilidade dos Testes , OvinosRESUMO
The dynamic features of nanosecond laser-induced cavitation bubbles near the light alloy boundary were investigated with the high-speed photography. The shock-waves and the dynamic characteristics of the cavitation bubbles generated by the laser were detected using the hydrophone. The dynamic features and strengthening mechanism of cavitation bubbles were studied. The strengthening mechanisms of cavitation bubble were discussed when the relative distance parameter γ was within the range of 0.5-2.5. It showed that the strengthening mechanisms caused by liquid jet or shock-waves depended on γ much. The research results provided a new strengthening method based on laser-induced cavitation shotless peening (CSP).
RESUMO
A new, sensitive and selective high-performance liquid chromatography-tandem mass spectrometric method has been developed for the determination of six major flavonoids including sophoricoside, genistin, genistein, rutin, quercetin, kaempferol in Fructus sophorae. Principal component analysis and hierarchical clustering analysis were used to classify and differentiate these samples. Chromatographic separation was performed on a C18 column with linear gradient elution of methanol and 0.05% acetic acid (v/v) at a flow rate of 0.8 ml/min. The detection was accomplished in the negative mode using multiple-reaction monitoring. The total run time was 8.0 min. Full validation of the assay was carried out including linearity, precision, accuracy, recovery, limit of detection and limit of quantification. The validated method was successfully applied to the simultaneous determination of these active components in Fructus sophorae. The results demonstrated that the quantitative difference in content of six active compounds was useful for chemotaxonomy of many samples from different sources and the standardization and differentiation of many similar samples. Simultaneous quantification of bioactive components by high-performance liquid chromatography-tandem mass spectrometric method coupled with chemometric techniques would be a well-acceptable strategy to comprehensively control the quality of Fructus sophorae.
RESUMO
A qualitative and quantitative determination method for chloropropanols in soy sauce was developed by GC-MS/MS with coupled column separation without derivatisation. The target compounds were 1,3-dichloropropan-2-ol (1,3-DCP), 2,3-dichloropropan-1-ol (2,3-DCP), 3-monochloropropane-1,2-diol (3-MCPD) and 2-monochloropropane-1,3-diol (2-MCPD). 3-MCPD-d(5) was used as an isotope internal standard for MCPDs and 1,3-DCP-d(5) for DCPs. After spiking with internal standards and mixed with 1 g of Extrelut™ NT, about 1 g of the sample was washed by 4 ml of hexane and the analytes were eluted with 15 ml of 95% (v/v) ethyl ether/hexane mixture. The concentrated extract was directly injected without derivatisation, separated by a coupled column - a 3 m Innowax (polyethylene glycol) combined with a 30 m DB-5 ms ((5%-phenyl)-methylpolysiloxane) by a quartz capillary column connector - and detected by GC-MS/MS. The limits of detection (LODs) in the sample matrix were 1.0, 2.5, 5.0 and 5.0 µg kg(-1) for the above chloropropanols, respectively. The relative proportions of 2-MCPD/3-MCPD ranged from 0.19 to 3.74 in soy sauce samples. 2,3-DCP and 2-MCPD were more stable than 1,3-DCP and 3-MCPD under alkaline condition. The levels of chloropropanols can be decreased by an alkaline treatment process.
Assuntos
Cromatografia Gasosa-Espectrometria de Massas/métodos , Hidrocarbonetos Clorados/análise , Propanóis/análise , Alimentos de Soja/análise , Padrões de ReferênciaRESUMO
Ni80Fe20 permalloy nanoparticles with narrow size distribution and homogeneous composition have been prepared by the polyol processing at 180 degrees C for 2 h and their particle sizes can be tunable in the size range of 20-440 nm by proper addition of K2PtCI4 agent. X-ray diffraction results show that the NiFe nanoparticles are of face centered cubic structure. The addition of K2PtCl4 does not affect the composition of NiFe NPs but decreases the particle size remarkably. Both saturation magnetization and coercivity of the as-prepared NiFe nanoparticles decrease with decreasing particle size. Annealed at 280 degrees C, however, the saturation magnetization of various sized NiFe nanoparticles increases drastically and approaches to the bulk for the -440 nm NiFe particles, and a maximum coercivity (-270 Oe) happens at a critical size of -50 nm. The magnetic property dependency of these NiFe nanoparticles on annealing has been discussed by considering the surface chemistry.
RESUMO
An ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method for simultaneous determination of 10 mycotoxins in grain was developed. The selected mycotoxins were: deoxynivalenol, 3-acetyldeoxynivalenol, 15-acetyldeoxynivalenol, nivalenol, fusarenon X, moniliformin, zearalenone, zearalanone, ochratoxin A and ochratoxin B. The samples were extracted with aqueous acetonitrile (84 : 16, v/v) and purified by reliable laboratory-made mixed cartridges. The analytes were separated on an Acquity UPLC HSS T3 column (100 × 2.1 mm, 1.8 µm) and eluted with a mobile phase of water containing 0.2% aqueous ammonia and acetonitrile/methanol (90 : 10, v/v). All mycotoxins were detected with a Waters Micromass Quattro Ultima Pt tandem quadrupole mass spectrometer operating in negative electrospray ionization using multiple reaction monitoring mode. Accurate determination was achieved by employing commercial ¹³C15-deoxynivalenol as internal standard, which compensated for target loss and eliminated matrix effects. The established method was further validated by determining the linearity (R² > 0.9990), average recovery (75.8-106.5%), sensitivity (limit of quantitation 0.09-8.48 µg kg⻹) and precision (relative standard deviation ≤ 6.9%). It was shown to be a suitable method for simultaneous determination of 10 mycotoxins in grain. Finally, a total of 69 corn samples randomly collected from eastern and northern China were analyzed. The results showed that deoxynivalenol was the most frequently detected contaminant, whilst 3-acetyldeoxynivalenol, 15-acetyldeoxynivalenol, nivalenol, zearalenone, zearalanone, fusarenon X and moniliformin also occurred frequently. Ochratoxin A and ochratoxin B were present only in trace amounts in a small number of samples.