Class-Irrelevant Feature Removal for Few-Shot Image Classification.

Most existing few-shot image classification methods employ global pooling to aggregate class-relevant local features in a data-drive manner. Due to the difficulty and inaccuracy in locating class-relevant regions in complex scenarios, as well as the large semantic diversity of local features, the class-irrelevant information could reduce the robustness of the representations obtained by performing global pooling. Meanwhile, the scarcity of labeled images exacerbates the difficulties of data-hungry deep models in identifying class-relevant regions. These issues severely limit deep models' few-shot learning ability. In this work, we propose to remove the class-irrelevant information by making local features class relevant, thus bypassing the big challenge of identifying which local features are class irrelevant. The resulting class-irrelevant feature removal (CIFR) method consists of three phases. First, we employ the masked image modeling strategy to build an understanding of images' internal structures that generalizes well. Second, we design a semantic-complementary feature propagation module to make local features class relevant. Third, we introduce a weighted dense-connected similarity measure, based on which a loss function is raised to fine-tune the entire pipeline, with the aim of further enhancing the semantic consistency of the class-relevant local features. Visualization results show that CIFR achieves the removal of class-irrelevant information by making local features related to classes. Comparison results on four benchmark datasets indicate that CIFR yields very promising performance.

High-throughput screening and quantification of pesticides in Lilii Bulbus using ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry.

Lilii Bulbus is a notable flower in Chinese cuisine, and has also been used as a Chinese herbal medicine for over 2000 years. This work presents an analytical method for rapidly screening multiple pesticide residues in Lilii Bulbus using ultra-high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF/MS). For sample pre-treatment, the QuEChERS method is employed, and targeted MS/MS is adopted for data acquisition. Moreover, a database containing 515 pesticides with accurate mass database and a high-resolution fragment ion spectrum library is established in this work. In addition, the qualitative and quantitative results of the screening method are validated. The results show that within the linear concentration range of 2 to 200 µg L-1, for each pesticide, 89.3% of the pesticides exhibit linear correlation coefficients R2 equal to or exceeding 0.990. The limit of quantification for all pesticides is below 50 µg kg-1. With a recovery of 70% to 120% and RSD ≤ 20% as the satisfactory standards, 387 (75.0%), 411 (79.7%) and 420 (81.4%) pesticides meet the standards at the three addition levels of 10 µg kg-1, 20 µg kg-1, and 100 µg kg-1, respectively. By utilizing the proposed method, pesticide residues in 100 samples are investigated, providing scientific data to ensure the safety of pesticide residues and demonstrating the general applicability of the method for routine monitoring of pesticide residues in Lilii Bulbus.

Magnetic graphitized carbon black based on crystal growth method combined with high-resolution mass spectrometry for screening of 300 pesticide residues in Radix Codonopsis and Angelica sinensis.

In this study, a high-throughput method for analyzing 300 pesticide residues in Radix Codonopsis and Angelica sinensis was established by liquid chromatography-quadrupole time-of-flight mass spectrometry (LC-Q-TOF/MS) using iron tetroxide loaded graphitized carbon black magnetic nanomaterial (GCB/Fe3O4) as the purification material. It was optimized that saturated salt water and 1 % acetate acetonitrile were used as the extraction solution, then the supernatant was purified with 2 g anhydrous CaCl2 and 300 mg GCB/Fe3O4. As a result, 300 pesticides in Radix Codonopsis and 260 in Angelica sinensis achieved satisfactory results. The limits of quantification of 91 % and 84 % of the pesticides in Radix Codonopsis and Angelica sinensis reached 10 µg/kg, respectively. The matrix-matched standard curves ranging from 10 to 200 µg/kg were established with correlation coefficients (R) above 0.99. The pesticides meeting SANTE/12682/2021 accounted for 91.3 %, 98.3 %, 100.0 % and 83.8 %, 97.3, 100.0 % of the total pesticides added in Radix Codonopsis and Angelica sinensis respectively, which were spiked at 10, 20,100 µg/kg. The technique was applied to screen 20 batches of Radix Codonopsis and Angelica sinensis. Five pesticides were detected, three of which were prohibited according to the Chinese Pharmacopoeia (2020 Edition). The experimental results showed that GCB/Fe3O4 coupled with anhydrous CaCl2 exhibited good adsorption performance and could be used for sample pretreatment of various pesticide residues in Radix Codonopsis and Angelica sinensis. Compared with the reported methods for determining pesticides in traditional Chinese medicine (TCM), the proposed method has the advantage of less time-consuming in the clean-up procedure. Furthermore, as a case study on root TCM, this approach may serve as a reference for other TCM.

A liquid chromatography-time-of-flight/mass spectrometry method for analysis of pesticides and transfer behavior in Radix Codonopsis and Angelica sinensis decoctions.

The safety of traditional Chinese medicine (TCM) has garnered considerable interest worldwide. In this study, a high-throughput method for the determination of 255 pesticide residues in decoctions of Radix Codonopsis and Angelica sinensis was developed using liquid chromatography-time-of-flight/mass spectrometry. The methodological verification demonstrated the accuracy and reliability of this method. The frequently detected pesticides in Radix Codonopsis and Angelica sinensis were determined to build a correlation between pesticide properties and the transfer rate of pesticide residues in their decoctions. Water solubility (WS) with a higher correlation coefficient (R) made a significant contribution to the accuracy of the transfer rate prediction model. The regression equations for Radix Codonopsis and Angelica sinensis were T = 13.64 log WS + 10.56 with a correlation coefficient (R) of 0.8617 and T = 10.66 log WS + 25.48 with a correlation coefficient (R) of 0.8072, respectively. This study provides preliminary data on the potential risk of exposure to pesticide residues in Radix Codonopsis and Angelica sinensis decoctions. Furthermore, as a case study on root TCM, this approach may serve as a model for other TCMs.

Image Hallucination From Attribute Pairs.

Recent image-generation methods have demonstrated that realistic images can be produced from captions. Despite the promising results achieved, existing caption-based generation methods confront a dilemma. On the one hand, the image generator should be provided with sufficient details for realistic hallucination, meaning that longer sentences with rich content are preferred, but on the other hand, the generator is meanwhile fragile to long sentences due to their complex semantics and syntax like long-range dependencies and the combinatorial explosion of object visual features. Toward alleviating this dilemma, a novel approach is proposed in this article to hallucinate images from attribute pairs, which can be extracted from natural language processing (NLP) toolsets in the presence of complex semantics and syntax. Attribute pairs, therefore, enable our image generator to tackle long sentences handily and alleviate the combinatorial explosion, and at the same time, allow us to enlarge the training dataset and to produce hallucinations from randomly combined attribute pairs at ease. Experiments on widely used datasets demonstrate that the proposed approach yields results superior to the state of the art.

Rapid Screening of ß-Agonists in Animal Hair by Thermal Desorption Electrospray Ionization Mass Spectrometry.

BACKGROUND: Even though the use of ß-agonists in livestock has been banned in many countries, ß-agonists abuse is still out of control owing to time-consuming and complicated determination techniques. OBJECTIVE: This study applied ambient thermal desorption electrospray ionization mass spectrometry (TD-ESI/MS) as a new strategy for rapidly screening seven ß-agonists. As it does not require pretreatment, this method allows on-site and real-time detection. METHOD: Samples were collected directly using a simple metal probe. Analytes on the probe were desorbed and ionized by TD-ESI, after which analyte ions were detected using a triple quadrupole mass analyser. RESULTS: The results showed that a thermal desorption temperature of 320°C and nebulizer pressure of 3 psi demonstrated the highest sensitivity. Excellent linear relationships were obtained in concentrations ranging from 10 to 400 µg/kg. The limit of detection of the method was 1-10 µg/kg with RSDs of 7.2-14.6%. A positive sample was verified using HPLC coupled with triple quadrupole tandem mass spectrometry, consistent with the results from TD-ESI/MS. CONCLUSION: This method was the first to apply TD-ESI/MS to rapid analyse ß-agonists in livestock hair and was proven to be accurate, fast, and environmentally friendly. Because qualitative screening for each analysis was completed within approximately 1 min, the method could contribute to preventing non-compliance in the flow of animal-derived food to the market. HIGHLIGHTS: This method was a promising method for the rapid screening of ß-agonists in livestock hair at any time of breeding without imposing any harm to animal which proven to be a rapid, in situ, and non-destructive detection technique without any pretreatment.

Automated QuEChERS for the determination of 482 pesticide residues in Radix codonopsis by GC-Q-TOF/MS and LC-Q-TOF/MS.

A rapid procedure for the determination of 482 pesticide residues in Chinese Materia Medica by GC-Q-TOF/MS and LC-Q-TOF/MS (379 pesticides for LC, 327 pesticides for GC, and 226 pesticides for both) was developed. Radix codonopsis was chosen as the matrix for verification, and a comparative study on the QuEChERS sample preparation was carried out, between a fully automated workstation and manual operation, in terms of limits of quantitation, recovery rate and RSD at 3 spiked levels of 10 µg kg-1, 20 µg kg-1 and 100 µg kg-1. In the linear range of each pesticide in a concentration range of 5-100 µg L-1, the linear correlation coefficients R2 of 85% of the pesticides for GC and 88% for LC were equal to or greater than 0.990. Taking recovery 70-120% and RSD ≤ 20% as the satisfactory standard, the automated workstation performed better at 10 µg kg-1 and 20 µg kg-1 than manual operation, and the numbers of satisfactory pesticides of GC & LC were 401 and 418 for the automated approach, and 378 and 400 for manual, while the two approaches were almost even at 100 µg kg-1, 421 vs. 424. Besides, the automated workstation presented lower RSD (more pesticides ≤10%) and better recovery quality (more pesticides within 90-110%). Following the method verification, 50 Radix codonopsis samples purchased from local markets were prepared with the automated workstation and analyzed by GC and LC-Q-TOF/MS. 18 pesticides were detected in 38 samples, one of which was a highly toxic pesticide. The automated QuEChERS workstation can handle 40 samples in one cycle within 6 hours, and realize whole-process automation covering from samples after "weighing" to "injection into vials". The batch-to-batch, day-to-day, and lab-to-lab consistency and 24 × 7 workability of the automated solution have demonstrated a promising and ideal replacement for manual operation in sample preparation.

[Determination of 118 pesticide residues in dried wolfberry by gas chromatography-triple quadrupole mass spectrometry in dynamic multiple reaction monitoring mode].

Wolfberry fruit is very popular among consumers because it is rich in nutrients. However, it is vulnerable to diseases caused by insect pest feeding and microbial pathogen infection. Pesticide application is the main approach for controlling wolfberry disease; however, various concerns have been raised regarding chemical residues in foodstuffs and consequent environmental contamination. Matrix interference is a significant challenge in trace analysis. Chromatography, coupled with MS techniques with high sensitivity and selectivity, proved to be a powerful tool for the detection of multi-pesticide residues in complex matrices. The traditional MRM mode has been gradually replaced by the dynamic MRM (dMRM) mode, which could dynamically allocate the retention time window of each target pesticide, significantly adjust the loading cycle time of multiple compounds, and improve the analysis efficiency. The QuEChERS pretreatment method, based on dispersive solid-phase extraction, has been widely used in the detection of pesticide residues in food because it is simple and rapid. In this study, a robust and high-throughput method was established for the simultaneous determination of 118 pesticide residues in wolfberry using the modified QuEChERS method, combined with gas chromatography-triple quadrupole mass spectrometry in dMRM mode. The optimal pretreatment method was determined by comparing the recovery rates obtained with different volumes of added water (5, 10, 15, and 20 mL), different extraction solvents (acetone, n-hexane, acetonitrile, and acetonitrile containing 0.1% formic acid), different extraction temperatures (normal temperature, -18 ℃ for 10 min and 20 min), water absorbent (anhydrous magnesium sulfate), and purification with primary secondary amine (PSA) and octadecylsilane (C18). The results showed that 5 g samples were rehydrated with 10 mL ultrapure water, extracted with 10 mL acetonitrile, frozen at -18 ℃ for 10 min, partitioned with buffer system salt package containing 4.0 g anhydrous magnesium sulfate, 1.0 g sodium chloride, 1.0 g sodium citrate, and 0.5 g disodium citrate, purified up with 800 mg MgSO4, 150 mg PSA, and 150 mg C18. Pesticides were separated on a capillary column HP-5MS UI (30 m×0.25 mm×0.25 µm), and quantified by a matrix-matched external standard method. The results showed that the 118 pesticides exhibited good linearity in the range from 20 to 640 µg/L, with correlation coefficients R2≥0.9923. The limits of detection and quantification were 0.006-28.344 µg/kg and 0.021-94.480 µg/kg, respectively. The average recoveries at four spiked levels of 0.01, 0.04, 0.10, and 0.20 mg/kg were in the range of 64.97%-126.21%, with relative standard deviations (RSDs) of 0.69%-18.86% (n=6). The results of the matrix effect showed that 82% of the pesticides exhibited matrix enhancement effects, while others showed matrix inhibition effects. In addition, 9% of the pesticides showed a strong matrix effect, while others showed moderate or weak matrix effects. The matrix effects could be reduced by the matrix-matched standard curve method. The proposed method was employed for the analysis of 10 real samples purchased from local markets. The results demonstrated that pesticides were detected in all the samples, 22 pesticides were detected in total, and 3-12 pesticides were found in a single sample. Chlorpyrifos, fipronil, cypermethrin, pyridaben, and difenoconazole were detected at high detection rates. The captan content in a batch of samples was 1.4066 mg/kg. Thus, the optimized method is simple, fast, accurate, and reliable, and it is suitable for the routine detection and rapid screening of the multi-pesticide residues in wolfberry.

[Rapid screening of illegally added poppy husk in hot pot sauce and soup by thermal desorption electrospray ionization-triple quadruple mass spectrometry].

A thermal desorption electrospray ionization-triple quadruple mass spectrometry (TD-ESI-MS/MS) method was developed for the rapid screening of poppy husk in hot pot sauce and soup. The solid surface or liquid sample was directly touched by a simple metal probe. The analytes collected on the probe were desorbed and ionized using a TD-ESI source, after which the analyte ions were detected by MS/MS in multiple reaction monitoring (MRM) mode. The results were compared with those of colloidal gold card rapid detection and verified by high performance liquid chromatography coupled with triple quadrupole mass spectrometry (HPLC-MS/MS). The instrument gave the best response with the highest sensitivity under the following conditions: thermal desorption temperature, 260 ℃; injection solvent, 0.1% formic acid aqueous solution containing 10 mmol/L formic ammonium-acetonitrile (1:1, v/v); flow rate, 200 µL/h. The limits of detection (LODs) for papaverine, noscapine, and thebaine in five alkaloids were 2 µg/kg, while those for codeine and morphine were 10 µg/kg in hot pot sauce and 5 µg/kg in soup. The sensitivity of this method was significantly superior to that of the colloidal gold card rapid detection. The method was applied to 50 batches of hot pot sauce and soup. Noscapine, papaverine, thebaine, and morphine were detected in a positive sample of chicken soup, which was consistent with the result of the HPLC-MS/MS method. This method without sample preparation and chromatographic separation is fast, green, and environmentally benign, thus being suitable for the rapid qualitative analysis of poppy husk in food.

Influence of Income Disparity on Child and Adolescent Education in China: A Literature Review.

This paper reviews how income inequality at the micro and regional levels influenced the inequality in educational outcomes for children and adolescents in China over the past decades. First, we find that the economic condition of the family influences children's and adolescents' education through home educational resources and parental involvement. Second, income disparity is significantly correlated with the regional differences in educational outcomes. Finally, the differences in the development of child and adolescent education between different regions are mainly due to the uneven distribution of educational resources, which is closely related to the public education financing system and local economic development.

Psychometric Evaluation of Somatic and Psychological Health Report: A Sample from Chinese Adolescents.

The purpose of the present study was to do a psychometric evaluation of the somatic and psychological health report (SPHERE) among Chinese adolescents. Our participants were 116 twins (50 females). Psychometric evaluation indicated that the reliability and validity of this scale were good. The internal consistencies and split-half reliabilities of all subscales were above 0.80. Furthermore, the item-total correlations were acceptable for all the subscales (all the values were higher than 0.20). The present findings suggest that the SPHERE can be well used to measure Chinese adolescents' somatic and psychological health.

Microfluidic Synthesis Enables Dense and Uniform Loading of Surfactant-Free PtSn Nanocrystals on Carbon Supports for Enhanced Ethanol Oxidation.

Developing new synthetic methods for carbon supported catalysts with improved performance is of fundamental importance in advancing proton exchange membrane fuel cell (PEMFC) technology. Continuous-flow, microfluidic reactions in capillary tube reactors are described, which are capable of synthesizing surfactant-free, ultrafine PtSn alloyed nanoparticles (NPs) on various carbon supports (for example, commercial carbon black particles, carbon nanotubes, and graphene sheets). The PtSn NPs are highly crystalline with sizes smaller than 2 nm, and they are highly dispersed on the carbon supports with high loadings up to 33 wt%. These characteristics make the as-synthesized carbon-supported PtSn NPs more efficient than state of the art commercial Pt/C catalysts applied to the ethanol oxidation reaction (EOR). Significantly enhanced mass catalytic activity (two-times that of Pt/C) and improved stability are obtained.

One-Step, Facile and Ultrafast Synthesis of Phase- and Size-Controlled Pt-Bi Intermetallic Nanocatalysts through Continuous-Flow Microfluidics.

Ordered intermetallic nanomaterials are of considerable interest for fuel cell applications because of their unique electronic and structural properties. The synthesis of intermetallic compounds generally requires the use of high temperatures and multiple-step processes. The development of techniques for rapid phase- and size-controlled synthesis remains a formidable challenge. The intermetallic compound Pt1Bi2 is a promising candidate catalyst for direct methanol fuel cells because of its high catalytic activity and excellent methanol tolerance. In this work, we explored a one-step, facile and ultrafast phase- and size-controlled process for synthesizing ordered Pt-Bi intermetallic nanoparticles (NPs) within seconds in microfluidic reactors. Single-phase Pt1Bi1 and Pt1Bi2 intermetallic NPs were prepared by tuning the reaction temperature, and size control was achieved by modifying the solvents and the length of the reaction channel. The as-prepared Pt-Bi intermetallic NPs exhibited excellent methanol tolerance capacity and high electrocatalytic activity. Other intermetallic nanomaterials, such as Pt3Fe intermetallic nanowires with a diameter of 8.6 nm and Pt1Sn1 intermetallic nanowires with a diameter of 6.3 nm, were also successfully synthesized using this method, thus demonstrating its feasibility and generality.

[Study on extraction process of Radix Bupleuri].

The orthogonal design was used to optimize extraction process of Radix Bupleuri with content of total saponin and yield of the extract as markers. Factors that have been chosen were ethanol concentration, ethanol consumption, extraction times and extraction time. Each factor had three levels. The result showed that the optimum extraction condition was 80% ethanol, 4 times the amount of material, refluxing for 4 times, 60 minutes each time. The optimized process was stable and workable.