Sampling analytes from cheese products for fast detection using neutral desorption extractive electrospray ionization mass spectrometry

The development of analytical techniques suitable for sensitive, high-throughput, and nondestructive food analysis has been of increasing interest in recent years. In this study, mass-spectral fingerprints of various cheese products were rapidly recorded in the mass range of m/z 50-300Da without any sample pretreatment, using neutral desorption extractive electrospray ionization mass spectrometry (ND-EESI-MS) in negative ion mode. The results demonstrate that both volatile and nonvolatile analytes on greasy cheese surfaces can be directly sampled by a neutral desorption gas beam. The influence of the neutral desorption gas flow on the analyte signal was systematically investigated. Under optimized experimental conditions, reproducible results were obtained using ND-EESI-MS. Principal component analysis was applied to differentiate a total of 49 individual cheese samples (four different types), which were purchased from three different supermarkets. All samples were successfully classified according to their types; but distributors and sensory properties were not distinguishable from the spectra data. The principal components 2, 3, and 4 scores showed an excellent capacity of distinguishing types of cheese. Molecular markers of interest can be identified using tandem mass spectrometry and matching the data with those from reference compounds. The experimental data show that ND-EESI-MS is able to sensitively and directly detect analytes on greasy surfaces without chemical contamination, providing a convenient method for high-throughput food analysis with a high degree of safet

Transcriptome Analyses Provide Insights into the Aggressive Behavior toward Conspecific and Heterospecific in Thitarodes xiaojinensis (Lepidoptera: Hepialidae)

Aggressive behavior in animals is important for survival and reproduction. It is well studied in adult insects, such as flies, ants, honey bees, and crickets. However, the larvae of Lepidopteran insects are also aggressive, studies of which are still lacking. Here, RNA-seq was used to generate a high-quality database for the aggressive behavior of Thitarodes xiaojinensis toward conspecifics and heterospecifics. Although there was similar aggressive behavior between the conspecific group and heterospecific group, significant differences were identified at the transcriptional level. When there was aggressive behavior toward conspecifics, T. xiaojinensis trended toward higher expression at the respiratory chain, while cuticle development and metabolism may have interfered. On the other hand, when there was aggressive behavior toward H. armigera, genes related to neuron and cuticle development, cellular processes, and its regulated signaling pathways were significantly upregulated, while the genes associated with oxidation-reduction and metabolism were downregulated. Weighted gene co-expression networks analysis (WGCNA) was performed, and two modules with properties correlating to the aggressive behavior of T. xiaojinensis were identified. Several hub genes were predicted and confirmed by qRT-PCR, such as CLTC, MYH, IGF2BP1, and EMC. This study provides a global view and potential key genes for the aggressive behavior of T. xiaojinensis toward conspecifics and heterospecifics. Further investigation of the hub genes would help us to better understand the aggressive behavior of insects

Research on the Control of Mining Instability and Disaster in Crisscross Roadways

In order to solve the disaster caused by the instability of spatial crisscross roadways under the action of leading abutment pressure in the coal mine face, combined with a specific engineering example, the methods of theoretical analysis, numerical simulation and field measurement are adopted to simulate and analyze the stress mutual disturbance intensity and influence range of spatial crisscross roadways. The evolution law of the plastic zone in spatial crisscross roadways under the influence of mining is explored, and the key to mining instability control is made clear. The roof of the return air roadway, the shoulder angle of the two sides and the coal wall are the key parts of surrounding rock stability control. On this basis, the cooperative control scheme of changing the roadway section shape (straight wall semicircular arch), supporting (anchor cable and “U” section steel) and modifying (grouting) is put forward. Through the field measurement, within the influence range of the return air roadway, the displacement deformation of the top and bottom is less than 200 mm, which achieves the goal of roadway safety and stability. Furthermore, based on the theory of “butterfly plastic zone”, the mechanical mechanism of the overall instability of the spatial crisscross roadway is revealed; that is, during the advance of the working face, the advance mining stress is superimposed with the surrounding rock stress of the crisscross roadway, and the peak value of the partial stress of the surrounding rock mass of the crisscross roadway is increased. The expansion of the plastic zone is intensified, and beyond 7 m from the crisscross position, the shoulder angle of the two sides and the leading plastic zone of the coal wall of the working face are connected with each other, which leads to the overall failure and instability of the surrounding rock between the roadways at the intersection

A Stand-Off Laser-Induced Breakdown Spectroscopy (LIBS) System Applicable for Martian Rocks Studies

Laser-induced breakdown spectroscopy (LIBS) is a valuable tool for evaluating the geochemical characteristics of Martian rocks and was applied in the Tianwen-1 Mars exploration mission with the payload called Mars Surface Composition Detection Package (MarSCoDe). In this work, we developed a laboratory standoff LIBS system combined with a Martian simulation chamber to examine the geochemical characteristics of igneous rocks, with the intention to provide a reference and a basis for the analysis of LIBS data acquired by MarSCoDe. Fifteen igneous geological standards are selected for a preliminary LIBS spectroscopic study. Three multivariate analysis methods were applied to characterize the geochemical features of igneous standards. First, quantitative analysis was done with Partial Least Squares (PLS) and Least Absolute Shrinkage and Selection (LASSO), where the major element compositions of these samples (SiO2, Al2O3, T Fe2O3, MgO, CaO, K2O, Na2O, and TiO2) were derived. The predicted concentrations ((Fe2O3 + MgO)/SiO2, Fe2O3/MgO, Al2O3/SiO2, and (Na2O + K2O)/Al2O3) were used to identify the geochemical characteristics of igneous rocks. Also, PCA, an unsupervised multivariate method was tested to directly identify the igneous rock lithology with no prior quantification. Higher correlation (0.82–0.88) are obtained using Principal Component Analysis (PCA) scores than using predicted elemental ratios derived by PLS and LASSO, indicating that PCA is better suited to identify igneous rock lithology than via quantitative concentrations. This preliminary study, using this LIBS system, provides suitable methods for the elemental prediction and geochemical identification of martian rocks, and we will use extended geologic standards and continue to build a robust LIBS spectral library for MarSCoDe based on this LIBS system in the future

A Stand-Off Laser-Induced Breakdown Spectroscopy (LIBS) System Applicable for Martian Rocks Studies

Laser-induced breakdown spectroscopy (LIBS) is a valuable tool for evaluating the geochemical characteristics of Martian rocks and was applied in the Tianwen-1 Mars exploration mission with the payload called Mars Surface Composition Detection Package (MarSCoDe). In this work, we developed a laboratory standoff LIBS system combined with a Martian simulation chamber to examine the geochemical characteristics of igneous rocks, with the intention to provide a reference and a basis for the analysis of LIBS data acquired by MarSCoDe. Fifteen igneous geological standards are selected for a preliminary LIBS spectroscopic study. Three multivariate analysis methods were applied to characterize the geochemical features of igneous standards. First, quantitative analysis was done with Partial Least Squares (PLS) and Least Absolute Shrinkage and Selection (LASSO), where the major element compositions of these samples (SiO2, Al2O3, T Fe2O3, MgO, CaO, K2O, Na2O, and TiO2) were derived. The predicted concentrations ((Fe2O3 + MgO)/SiO2, Fe2O3/MgO, Al2O3/SiO2, and (Na2O + K2O)/Al2O3) were used to identify the geochemical characteristics of igneous rocks. Also, PCA, an unsupervised multivariate method was tested to directly identify the igneous rock lithology with no prior quantification. Higher correlation (0.82–0.88) are obtained using Principal Component Analysis (PCA) scores than using predicted elemental ratios derived by PLS and LASSO, indicating that PCA is better suited to identify igneous rock lithology than via quantitative concentrations. This preliminary study, using this LIBS system, provides suitable methods for the elemental prediction and geochemical identification of martian rocks, and we will use extended geologic standards and continue to build a robust LIBS spectral library for MarSCoDe based on this LIBS system in the future

Sampling analytes from cheese products for fast detection using neutral desorption extractive electrospray ionization mass spectrometry

ISSN:1618-2650ISSN:1618-264

Investigation on the Cu-Dopant-Induced Modulation Effect on the Optoelectronic Efficiency and the Stability of CsPbBr₃ Perovskites

This study explores the use of Cu dopant to improve the optoelectronic properties and stability of CsPbX3 perovskites for blue-light-emitting diode material. The addition of Cu causes the metal octahedron of orthorhombic CsPbBr3 to shrink, which relaxes the lattice strain from the distortion and twisting of the [PbX6] octahedron and reduces energy from Jahn–Teller effects. A crystal orbital Hamilton population (COHP) analysis reveals that the Cu-Br bond in the [CuX6] octahedron has a higher integrated projected COHP (IpCOHP), and the strong hybridization between the Cu-3d and Br-4p bond enhances the bond interaction and the whole crystalline lattice. The addition of Cu dopants in CsPbBr3 perovskites results in a stronger framework that suppresses intrinsic defects like Br vacancies, leading to enhanced photoluminescence (PL) performance. Additionally, the Cu-3d orbitals contribute to the valence band and increase the band gap, resulting in a blue shift of the luminescence from Cu-doped CsPbBr3. These findings indicate that Cu dopants significantly improve the luminescence efficiency and the stability of CsPbBr3 perovskites, making them suitable for blue light LED applications

A New Spectral Transformation Approach and Quantitative Analysis for MarSCoDe Laser-Induced Breakdown Spectroscopy (LIBS) Data

Zhurong rover successfully landed on the southern of Utopia Planet of Mars on 15 May 2021. One laser-induced breakdown spectroscopy (LIBS) system, the main payload of the Mars Surface Composition Detector (MarSCoDe), was installed on the Zhurong rover aimed to measure the elements and their abundance in Martian regolith. Now, there are three sets of LIBS system (ChemCam, SuperCam and MarSCoDe) working on Mars at difference landing sites with diverse geologic features. For Mars exploration, cross-validation is necessary to expand the model compatibility, test data validity, and get more available data of the same type payloads. Spectral transformation approach is the first step and crucial for cross-validation of LIBS analysis model. Herein, a new 4-step spectral transformation approach was proposed to transform the LIBS spectra between three different LIBS systems (i.e., ChemCam, MarSCoDe, SDU-LIBS (recorded by self-built LIBS system)), whose data were partly different in spectral characteristics. Based on this approach, SDU-LIBS and MarSCoDe spectra data were transformed into ChemCam uniform and then the three kinds of LIBS data can have more similar spectral features and share one PLS (partial least squares) model for quantitative analysis. Our approach enables to make up the signal differences between different LIBS systems and gets acceptable quantitative analysis results of SDU-LIBS and MarSCoDe spectra using quantitative PLS model built by ChemCam calibration sample set. This work verified feasibility and availability of our approach for cross validation of different LIBS systems. Based on this method, MarSCoDe data were analyzed and got the preliminary satisfying results although no analysis model of laboratory replica payload was available under the existing conditions

Cryogenic origin of fractionation between perchlorate and chloride under modern martian climate

International audienceAbstract The high perchlorate (ClO 4 − ) to chloride (Cl − ) ratios observed at the Phoenix landing site, northern polar region of Mars, have been puzzling since detection. However, a lack of understanding of perchlorate-chloride-water systems under cryogenic conditions makes it difficult to assess ClO 4 − /Cl − ratios during deliquescence-related processes. Here we quantitatively evaluate ClO 4 − /Cl − fractionation in deliquescence-induced brines of magnesium- and calcium-perchlorate-chloride salt mixtures under subzero conditions, by measuring solubility data and constructing temperature-dependent thermodynamic models. We find that under specific relative humidity (RH) and temperature ( T ) conditions, deliquescence of perchlorate-chloride mixtures may form brines with fractionated ClO 4 − /Cl − signatures. Appropriate RH -T , water-limited conditions, and aeolian processes are required to produce and preserve the elevated ClO 4 − /Cl − signatures in soils. Under the present climate, the north polar region can support ClO 4 − /Cl − fractionation and potentially enrich perchlorate for longer periods on global Mars. This highlights the uniqueness of Mars’ arctic environment and its implications for modern habitability