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Normal-phase (NP) liquid chromatography is one of the most effective methods for separating isomers with sensitive structural features, including xanthophyll isomers. In this work, reverse-phase (RP) and NP liquid chromatography (LC), with silica gel and diol phase, respectively, were evaluated for the separation of xanthophyll isomers. The results showed that RP LC with monomeric C18 phase not only poorly separate all xanthophyll isomers in egg yolk but also requires additional sample preparation to eliminate triacylglycerols in egg yolk. The diol phase of NP-LC provided the highest efficiency for separating lutein, zeaxanthin, and their cis-isomers with isocratic separation using mobile phases consisting of n-hexane and polar modifiers (such as acetone, methyl tert-butyl ether, or ethyl acetate). To determine the xanthophyll content, peak areas from LC and total absorbance from spectrophotometry measurements were used. The approach was applied to analyze the xanthophylls of nine commercial egg samples. The results revealed that five out of nine analyzed samples contained a high level of canthaxanthin, which contributes to color enhancement but not to prevent age-related macular degeneration. Together, it shows that NP LC with diol phase combined with spectrophotometry is a powerful tool to monitor xanthophylls in eggs.
Asunto(s)
Yema de Huevo , Xantófilas , Yema de Huevo/química , Cromatografía Líquida de Alta Presión , Xantófilas/análisis , Xantófilas/química , Espectrofotometría , Animales , IsomerismoRESUMEN
Introduction: The manifestations of cardiac metastases are extremely variable depending on their location and extension. Case presentation: A 62-year-old man was admitted to the cardiac emergency department presenting with chest pain, worsening shortness of breath and palpitations. He had a history of esophageal squamous cell carcinoma treated with chemoradiotherapy, and he was not diagnosed with cardiovascular disease before. The electrocardiogram showed significant ST-segment elevations in leads II, III, and aVF. Initially, the patient was diagnosed with ST-segment elevation myocardial infarction. A cardiac point-of-care ultrasound was performed immediately revealing two large heterogeneous masses in the left ventricular wall and the apex, which changed the diagnosis and the management strategy. There was no significant change in serial cardiac biomarkers in the setting of persistent STE. Thoracic computed tomography and cardiac magnetic resonance confirmed that the patient was suffering from cardiac and lung metastases. Conclusion: ECG findings of localized and prolonged STE without Q waves or changes in biomarkers may suggest myocardial tumor invasion, especially in the cancer setting. Cardiac point-of-care ultrasound is an effective, convenient, noninvasive imaging modality to guide real-time clinical decision-making.
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Introduction: Prosthetic valve infective endocarditis (PVE) is a diagnostic challenge even in the era of multimodality cardiovascular imaging. Case presentation: The patient was a 67-year-old male with a three-year history of bioprosthetic aortic valve replacement who presented with persistent fever and negative blood cultures. The initial transthoracic echocardiography revealed a thickened aortic root. An abscess formation was visualized upon subsequent three-dimensional transesophageal echocardiography and positron emission tomography/computerized tomography (PET/CT). The patient underwent an urgent necrotic tissue debridement and a redo Bentall surgery. The real-time polymerase chain reaction of excised tissues was positive for Streptococcus. Clinical discussion: The diagnosis of PVE and its complications requires the integration of clinical, microbiological, and serial imaging data. Although advanced imaging modalities like PET/CT allow a timely diagnosis and management, their routine use in resource-limited scenarios is difficult. Conclusion: Multimodality cardiovascular imaging plays an important role in the diagnosis of PVE. Serial echocardiographic and clinical assessments are possible alternatives when the access to advanced cardiovascular imaging modalities is limited.
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A novel nanostructured electrode material based on electrochemically reduced graphene oxide/polyaniline nanowires/silver nanoflowers (ERGO/PANi NWs/AgNFs) was fabricated site-specifically onto a Pt microelectrode (0.80 mm2 area) using a three-step electrochemical procedure: electrosynthesis of ERGO, electropolymerization of PANi NWs, and electrodeposition of AgNFs. Synergistic and complementary properties of ERGO, PANi NWs and AgNFs, including high electrochemical activity, large surface area, and high biocompatibility, were obtained. Besides, the electrosynthesis method allowed the direct formation of the desired nanomaterial onto the Pt microelectrode, so the adhesion between the sandwich-structured nanocomposite and the electrode surface was also improved. The optimized ERGO/PANi NWs/AgNFs nanocomposite was used for the first time to develop an electrochemical DNA sensor. As a result, the DNA probe immobilization was facilitated and the electrochemical signals of the DNA sensor were enhanced. The detection limit of the DNA sensor was 2.70 × 10-15 M. Moreover, potential miniaturization for fabrication of a lab-on-a-chip system, direct detection, high sensitivity, and good specificity are the advantages of the fabricated DNA sensor.
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Two novel azo-colorants derived from phloroglucinol and antipyrine as well as 10 metal complexes with Co(ii), Ni(ii), Zn(ii), Cu(ii), and Cd(ii) were isolated and studied by a set of methods (1H, 13C NMR, IR, UV-VIS, EPR, X-ray structure determination). The azo-coupling of phloroglucinol with a 5-pyrazolone amino-derivative led to the isolation of a colorant H3L1 which was presented in the hydroxy-azo tautomeric form. At nitrosation of H3L1, the product H3L2 was isolated, which can be described as tri-oxo di-hydroxylamino hydrazone. According to the X-ray structure determination, the Cd-complex of H3L1 exhibited the dimeric form with two unionized organic ligands in the inner sphere. It was also found that chloride anions bridge two cadmium cations to form dimers. According to EPR spectra, the Cu-complex with H3L1 exhibited distorted tetragonal symmetry associated with the d x 2-y 2 ground state rather than d z 2 , and the corresponding Cu-H3L2 complex was described by a cubic symmetry of the coordination medium. Both H3L1, H3L2, and their metal complexes show coloristic activity towards wool, polyamide, and polyacetate fibers, which are strongly resistant towards UV-irradiation. The H3L2 compound possessed good sorption activity towards heavy metal cations from aqueous solutions of trace concentrations both under static and dynamic conditions.
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This paper investigates the friction coefficient of a moving liquid marble, a small liquid droplet coated with hydrophobic powder and floating on another liquid surface. A floating marble can easily move across water surface due to the low friction, allowing for the transport of aqueous solutions with minimal energy input. However, the motion of a floating marble has yet to be systematically characterised due to the lack of insight into key parameters such as the coefficient of friction between the floating marble and the carrier liquid. We measured the coefficient of friction of a small floating marble using a novel experimental setup that exploits the non-wetting properties of a liquid marble. A floating liquid marble pair containing a minute amount magnetite particles were immobilised and then released in a controlled manner using permanent magnets. The capillarity-driven motion was analysed to determine the coefficient of friction of the liquid marbles. The "capillary charge" model was used to fit the experimental results. We varied the marble content and carrier liquid to establish a relationship between the friction correction factor and the meniscus angle.