Salmonella is a principal causal agent of pathogenic outbreaks via food. A universal, highly sensitive and visual Salmonella detection method was proposed in this paper, based on a universal linker PCR (UL-PCR)-triggered Strand Displacement Amplification (SDA). In this research, the UL-PCR achieved the primary amplification. The universal linker primer was ingeniously designed and composed of two parts, one of which was the binding sequence of the target, and the other was the universal linker. Complementary sequences of the G-quadruplex and the nicking endonuclease recognition sequence were included in the universal linker. Therefore, the G-quadruplexes and nicking sites were successfully introduced into the UL-PCR products, providing a basis for further SDA triggering. SDA achieved the secondary signal amplification and generated a large amount of label-free DNAzymes. Following SDA, DNAzymes catalyzed 3,3',5,5'-tetramethylaniline (TMB) into colored compounds visible to the naked eye. We obtained the best experimental conditions by univariate analysis. Under optimal conditions, this proposed universal label-free method could detect Salmonella genome at level as low as 22 copies mL-1, with an excellent linear range between 102 copies mL-1 and 107 copies mL-1. And the limit of quantification (LOQ) was 102 copies mL-1. This strategy shows promise for broad applications.The increased attraction of biological volatile compounds has opened the route to a wide variety of sampling techniques, amongst which trap tubes packed with adsorbent materials are commonly used. Many types of adsorbent materials are available and the choice of the adsorbent can impact the obtained results in untargeted analysis. Therefore, a proper combination of the adsorbent material and the sample is necessary to increase the robustness and reproducibility of biological studies. In this study, the sampling performance of thermal desorption tubes with six common adsorbent material combinations, i.e., Tenax® TA, Tenax® TA/Carbopack™ B, Tenax® TA/Sulficarb, Tenax® TA/Carbograph™ 5TD, Tenax® TA/Carbograph™ 1TD/Carboxen® 1003, and Carboxen® 1016/Carbograph™ 5TD, was evaluated in two different setups in vitro and in vivo sampling. The in vitro setup consisted of the headspace dynamic extraction of spiked serum, and a mixture of 19 standards was evaluated in terms of response and reproducibility. The in vivo setup consisted into two parts the first one was based the evaluation of the standard mixture, which was flash-vaporised into Tedlar® bags containing exhaled breath; the second part was based on the longitudinal monitoring of breath metabolites originating from a beverage intake (i.e., brewed coffee), over a 90 min time period. The tubes were all desorbed and analysed in a comprehensive two-dimensional gas chromatography system coupled to a high-resolution time-of-flight mass spectrometer (GC × GC-HR ToF MS). In both sampling setups, the widest analytes coverage and the overall best extraction yield on the selected compounds were obtained using Tenax® TA, followed by Tenax® TA/Carbopack™ B. Tenax® TA provided the highest sampling reproducibility with 12 %RSD, 10 %RSD and less then 5 %RSD of the response during the experiments using the in vitro setup, the in vivo setup, and during the longitudinal tracking, respectively.Superoxide anion (O2•-) is an important biomarker for reactive oxygen species (ROS) generated through physiological and pathological processes. However, due to the short half-life of O2•- and high autofluorescence of cell tissues, in situ real-time tracking and monitoring of endogenous O2•- can be difficult. In this paper, a fluorescent probe IFP-O2 was developed to detect endogenous O2•- in cells. The probe could instantaneously react with O2•- to produce fluorescence off-on effect; its detection limit was as low as 10 nM. Cell experiments also showed that the probe had low toxicity and mitochondrial targeting ability. The article presents, for the first time, a probe that can be employed to measure endogenous O2•- in oral cancer Cal-27 cells and is a promising tool for monitoring and evaluating apoptosis.It has seen increasing development of reliable, robust, and flexible biosensors for rapid food-safety analysis in the past few decades. Recently, functional nucleic acid-based biosensors have attracted attention because of their programmability, bottom-up characteristics, and structural switches. However, few systematic reviews devoted to categorizing the potential of DNA nanostructures and devices were found for detecting food contaminants. Hence, the applications of functional nucleic acid-based biosensors were reviewed for analyzing food contaminants, including foodborne pathogen bacteria, biotoxins, heavy metals, and et al. In addition to categorizing the various biosensors, multiple signal readout strategies, such as optical, electrochemical, and mass-based signals were also examined. Finally, the future changes and potential opportunities, as well as practical applications of functional nucleic acid-based biosensors were discussed.This paper proposes a ROC curve-based methodology to find optimal classification model parameters. ROC curves are implemented to set the optimal number of PCs to build a one-class SIMCA model and to set the threshold class value that optimizes both the sensitivity and specificity of the model. The authentication of the geographical origin of extra-virgin olive oils of Arbequina botanical variety is presented. The model was developed for samples from Les Garrigues, target class, Samples from Siurana were used as the non-target class. Samples were measured by FT-Raman with no pretreatment.  https://www.selleckchem.com/products/a2ti-2.html  PCA was used as exploratory technique. Spectra underwent pre-treatment and variables were selected based on their VIP score values. ROC curve and others already known criteria were applied to set the threshold class value. The results were better when the ROC curve was used, obtaining performance values higher than 82%, 75% and 77% for sensitivity, specificity and efficiency, respectively.This study substantially synthesized the β-type MnO2 nano-flowers assembled by the hierarchical nano-sheets using a simplified hydro-thermal procedure. According to the FESEM images, MnO2 nano-flower exhibited diameter of ∼800 nm and fabricated with a lot of irregular sheets as a petal-like structure with thickness of several nano-meters. Therefore, the study focused on the construction of an electro-chemical sensor to simultaneously determine theobromine (ThB), theophylline (ThP), as well as caffeine (CaF) on the basis of the β-type hierarchical structure of the MnO2 nano-flowers (βH-MnO2-NF) modified electrode (βH-MnO2-NF/GCE). Analysis showed an acceptable linear association between the oxidation peak current and ThB, ThP and CaF concentration within the ranges between 0.01 and 320.0 μM with a limit of detection (LOD) equal to 8.7, 5.9, and 10.1 nM (S/N = 3), respectively. Additionally, this study intended to investigate ThB, Thp and CaF bio-availability in the five commercially available brands of the chocolate products and drug.