•An HPTLC-bioautography based screening for multi antibiotic residues detection was established.•The bio-compatibility of various HPTLC layers to Aliivibrio fischeri was evaluated.•Under optimized ...conditions, method sensitivity meats the strictest EU MRLs for the analytes.•A “substance-window” strategy was developed to circumvent background noises due to food matrices.
The world-wide usage and partly abuse of veterinary antibiotics resulted in a pressing need to control residues in animal-derived foods. Large-scale screening for residues of antibiotics is typically performed by microbial agar diffusion tests. This work employing high-performance thin-layer chromatography (HPTLC) combined with bioautography and electrospray ionization mass spectrometry introduces a rapid and efficient method for a multi-class screening of antibiotic residues. The viability of the bioluminescent bacterium Aliivibrio fischeri to the studied antibiotics (16 species of 5 groups) was optimized on amino plates, enabling detection sensitivity down to the strictest maximum residue limits. The HPTLC method was developed not to separate the individual antibiotics, but for cleanup of sample extracts. The studied antibiotics either remained at the start zones (tetracyclines, aminoglycosides, fluoroquinolones, and macrolides) or migrated into the front (amphenicols), while interfering co-extracted matrix compounds were dispersed at hRf 20–80. Only after a few hours, the multi-sample plate image clearly revealed the presence or absence of antibiotic residues. Moreover, molecular information as to the suspected findings was rapidly achieved by HPTLC-mass spectrometry. Showing remarkable sensitivity and matrix-tolerance, the established method was successfully applied to milk and kidney samples.
•A rapid TLC platform was established to screen for the most prior antibiotics in milk.•Clear separation of seven antibiotics was obtained on budget silica gel–EDTA plates.•Highly specific and ...sensitive fluorescence detection fulfills the low MRLs in milk.•Time-resolved TLC–MS analysis allows distinguishable MS confirmation on EDTA plates.
A rapid and efficient method for preliminary screening of four tetracyclines (tetracycline, chlortetracycline, oxytetracycline, doxycline) and three fluoroquinolones (enrofloxacin, ciprofloxacin, marbofloxacin), mostly detected in milk, by high-performance thin-layer chromatography–fluorescence detection and electrospray ionization mass spectrometry (HPTLC–FLD–ESI/MS) is highlighted. The optimized separation of the target antibiotics on ethylenediamine tetraacetic acid modified silica gel plates showed marked benefits for screening purposes. Besides, selective and sensitive densitometry in fluorescence mode was established with excitation at 366nm for the tetracyclines, 300nm for enrofloxacin and ciprofloxacin, and 280nm for marbofloxacin. Limits of detection (LOD) and quantitation (LOQ) with 95% confidence were in the range of 12–25 and 45–95μg/kg, respectively, in milk samples. Recoveries of target antibiotics from milk samples spiked at three critical levels (50, 100 and 150μg/kg) ranged from 76% to 105%. More importantly, a mass selective detection (MSD) was established as additional tool for confirmatory purposes. Using the elution-head based TLC–MS interface, the optimized elution flow consisting of acetonitrile/ammonium formate buffer (9/1, v/v) at a rate of 0.3mL/min enabled time-dependent resolution of analytes from the major interfering compounds, thus circumventing serious ion suppression effects. The established MSD assay also offered high sensitivity (25μg/kg) for confirmation, meeting Commission Regulation (EU) No. 37/2010.
Recently there was a new wave of research activities studying the decarburization behavior of spring steels with the main focus on the formation mechanism of a columnar ferrite layer within a certain ...temperature range which could not be explained by conventional decarburization theories. A new theory successfully developed recently in interpreting the oxide scale reduction mechanism on steel was then developed further and applied to interpret the observed columnar ferrite formation on spring steels. The essence of the new theory is that steel decarburization in the presence of a FeO scale on the steel surface is caused and governed by the reaction between the FeO scale and dissolved carbon in the steel, and therefore, the carbon concentration on the steel surface is determined by the FeO-steel interface equilibrium and cannot be treated as negligible within the temperature range where ferrite is able to form, because the equilibrium interface carbon concentration is in the same magnitude as the carbon solubility in ferrite. The new theory and available solutions for different decarburization scenarios using decarburization of 60Si2MnA as an example are summarized in this review. Explanations are given to interpret discrepancies between experimental observations and theoretical predictions. New areas for future research are also identified.
•A screening-oriented method based on HPTLC-FLD-ESI/MS was proposed for sulfonamide residues in foods.•Selective quantitation by fluorescence densitometry was validated to meet the strictest residue ...limits.•An efficient HPTLC-MS detection was used for rapid identification of detected zones.•Screening tasks can be done with high throughput at relatively low costs.
In the European Union (EU), sulfonamides are among the most widely administrated groups of antibiotics in animal husbandry. Therefore, monitoring their residues in edible animal tissues plays an important role in the EU food safety framework. In this work, a simple and efficient method for the rapid screening of twelve prior sulfonamides frequently prescribed as veterinary drugs by high-performance thin-layer chromatography (HPTLC) was established. Sample extracts obtained with acetonitrile were tenfold concentrated and applied to HPTLC without any further cleanup. Following separation and fluram derivatization, sensitive and selective quantitation of the analytes can readily be accomplished with fluorescent densitometry. Limits of detection and quantitation were 15–40 and 35–70μg/kg, respectively. Additionally, a confirmative detection by HPTLC-electrospray ionization mass spectrometry (HPTLC-ESI/MS) was optimized, offering straightforward identification of target zones. Therefore, the risk of potential false positive findings can efficiently be reduced. The method was validated to meet the enforced commission regulation (EU) No. 37/2010, regarding different matrix complexities (bovine milk, porcine liver and kidney).
The decarburization behavior of a spring steel 60Si2MnA at 700 °C to 900 °C was examined. It was observed that after holding for 20 minutes in 20 pct H
2
O-N
2
, thick ferrite layers developed within ...750 °C to 877 °C with a maximum thickness of about 100
μ
m observed at 805 °C to 825 °C, while the ferrite layers were much thinner at 900 °C and 700 °C. Carbon permeability analysis and theoretical calculation were conducted to assess the possibility of forming a ferrite layer. In the permeability analysis, several factors were considered: (1) carbon concentration at the steel surface, which was very likely determined by reaction equilibrium between FeO and dissolved carbon in steel, (2) carbon solubility in ferrite which had a maximum value at about 715 °C, and (3) carbon diffusivity in the ferrite phase. In the ferrite layer thickness calculation, the contribution from carbon diffusion in the austenite phase was also taken into account. While the carbon permeability analysis and ferrite layer thickness calculation showed good successes in predicting the pattern of ferrite layer thickness change with temperature, under the assumption of FeO-ferrite equilibrium the calculated ferrite layer thicknesses at 780 °C to 840 °C did not match the observed values well. Factors contributing to the discrepancy were discussed.
The current study uses the Pandat™ software developed by CompuTherm to simulate the solidification sequence of the 2 pct Mg-55 pct Al-1.6 pct Si-Zn (wt pct) coating on steel. Using the Scheil model ...approach, the solidification process of the coating alloy is revealed to proceed in the following sequence: (i) primary (Al) formation at
T
= 553.3 to 475 °C, (ii) Si formation at
T
= 475 to 437.9 °C, (iii) simultaneous Si and Mg
2
Si formation at
T
= 437.9 to 383.6 °C, (iv) MgZn
2
formation at
T
= 383.6 to 336.9 °C, and finally (v) simultaneous formation of (Zn) and MgZn
2
at
T
= 336.9 °C to complete the solidification process, with (Al) being an important participating component throughout, and Si a significant component at Stages (ii) and (iii) and becoming insignificant at Stages (iv) and (v). It is also revealed that the remaining liquid composition varies significantly throughout the solidification process, and therefore, different isopleths must be produced to illustrate the starting solidification reactions at different stages. The simulation results are then used to interpret the complex microstructures observed in the coating.
Lung cancer is a major threat to public health and remains difficult to treat. Repositioning of existing drugs has emerged as a therapeutic strategy in lung cancer. Clinically, low-dose montelukast ...has been used to treat asthma.
We evaluated the potential of using montelukast to treat lung cancer.
Migration was detected using wound-healing and Transwell assays, the expression of CysLT1 using western blotting, and subcellular localization of CysLT1 using immunofluorescence. CRISPR/Cas9 technology was used to further investigate the function of CysLT1.
Subcellular localization staining showed that the CysLT1 distribution varied in murine and human lung cancer cell lines. Furthermore, montelukast suppressed CysLT1 expression in lung cancer cells. The treated cells also showed weaker migration ability compared with control cells. Knockout of CysLT1 using CRISPR/Cas9 editing in A549 cells further impaired the cell migration ability.
Montelukast inhibits the migration of lung cancer cells by suppressing CysLT1 expression, demonstrating the potential of using CysLT1 as a therapeutic target in lung cancer.
Shoulder stiffness (SS) is a common shoulder disease characterized by increasing pain and limited range of motion. SS is considered to be an inflammatory and fibrotic disorder pathologically. ...However, there is no consensus on the most effective conservative treatment for fibrosis. Given that human Bone Marrow Mesenchymal Stem Cell-derived extracellular vesicles (BMSC-EVs) displayed promising therapeutic effects for various tissues, we investigated the therapeutic effect of BMSC-EVs on fibrosis in a mice immobilization model and two cell models. By conducting a series of experiments, we found that BMSC-EVs can significantly inhibit the fibrogenic process both in vitro and in vivo. In detail, BMSC-EVs suppressed the aberrant proliferation, high collagen production capacity, and activation of fibrotic pathways in TGF-β-stimulated fibroblasts in vitro. Besides, in vivo, BMSC-EVs reduced cell infiltration, reduced fibrotic tissue in the shoulder capsule, and improved shoulder mobility. In addition, via exosomal small RNA sequencing and qPCR analysis, let-7a-5p was verified to be the highest expressed miRNA with predicted antifibrotic capability in BMSC-EVs. The antifibrotic capacity of BMSC-EVs was significantly impaired after the knockdown of let-7a-5p. Moreover, we discovered that the mRNA of TGFBR1 (the membrane receptor of transforming growth factor β) was the target of let-7a-5p. Together, these findings elucidated the antifibrotic role of BMSC-EVs in shoulder capsular fibrosis. This study clarifies a new approach using stem cell-derived EVs therapy as an alternative to cell therapy, which may clinically benefit patients with SS in the future.
Schematic depiction. Human bone marrow mesenchymal stem cell-derived EVs inhibit capsular fibrosis via transferring let-7a-5p and targeting TGFBR1. Display omitted
•This study firstly demonstrated BMSC-EVs could inhibit TGF-β induced fibroblast activation/collagen secretion in vitro and extenuate capsular stiffness in vivo.•The therapeutic effect of BMSC-EVs was related to exosomal let-7a-5p, a highly expressed miRNA in BMSC-EVs.•This study clarifies a new approach using stem cell-derived EVs therapy, as an alternative to cell therapy, which may clinically benefit patients with frozen shoulder.
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•HIU treatment enhanced the springiness and gumminess of marinated egg.•The zeta potential and hydrophobicity of protein gels improve after HIU.•HIU at 100 W affects rheological ...behaviors by boosting non-covalent bonds.•The aggregation behaviors are due to the decrease in α-helix while the increase in β-turn.•The porous network structure and in vitro digestibility were also enhanced after HIU.
In this study, high intensity ultrasonication (HIU) was employed as an efficient tool to improve the gel property and in vitro digestibility of marinated egg (ME). The effects of HIU treatment at 100 W and 200 W for a series of time periods (0.5 h, 1 h, and 2 h) on the textural profiles, structural changes, and microstructures were also studied. After HIU treatment, the springiness and gumminess of ME white were enhanced. The water holding capacity reached the highest point (66.6%) when 0.5 h 200 W HIU was used. It was observed that 100 W HIU led to the highest zeta potential (-12.0 mV) and hydrophobicity (175.35 μg) of ME, indicating a high degree of electrostatic repulsion prevented agglomeration. HIU treatment at 100 W affected the dynamic rheological behaviors by boosting non-covalent bonds, which maintains the gel network's homogeneity. Meanwhile, the decreasing formation of α-helix, in contrast to β-turn, altered the aggregation behaviors of egg white gel. The microstructure of the 200 W HIU treated samples had porous colloidal network structures, and the in vitro digestibility (>75%) was increased after HIU. This work demonstrated that HIU could be a green and cost-effective tool for processing the egg product with high quality.
is a common cause of
infections. In our present study, we investigated the antifungal susceptibility and molecular epidemiology of vaginal and non-vaginal
isolates. Seventy-six vaginal
strains ...isolated from patients with vulvovaginal candidiasis and 57 non-vaginal
isolates were collected at two hospitals in Shanghai, China. Antifungal susceptibility was examined using a broth microdilution method. Multilocus sequence typing was used for genotyping. Overall, 28 (21.1%), 28 (21.1%), and 29 (21.8%)
isolates were resistant to fluconazole, itraconazole, and voriconazole, respectively. Briefly, 18 (23.7%), 18 (23.7%), and 19 (25%) vaginal strains were resistant to fluconazole, itraconazole, and voriconazole. While the resistance to these antifungals were all 17.5% (10/57) in non-vaginal strains. All isolates retained susceptibility to amphotericin B, and only four non-vaginal isolates were caspofungin resistant. Genotyping identified 17 ST patterns. In non-vaginal samples, the same genotypes appear as in the vaginal samples, except for one genotype (ST-182), while in the vaginal samples more genotypes appear (ST8, ST19, ST45, ST55, ST66, ST80, ST138, and ST17). The most common genotype was ST7 (81 strains), followed by ST10 (14 strains) and ST15 (11 strains). The majority of resistant phenotype strains (25/30, 83.3%) correlated to the predominant genotype (ST7), and the rest belonged to ST3 (2/30, 6.7%), ST10 (1/30, 3.3%), ST19 (1/30, 3.3%), and ST45 (1/30, 3.3%). Our survey revealed cross-resistance in vaginal and non-vaginal
isolates. Moreover, there is no genotype associated with the resistance phenotype.
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