LNAS: a clinically applicable deep-learning system for mediastinal enlarged lymph nodes segmentation and station mapping without regard to the pathogenesis using unenhanced CT images.

BACKGROUND: The accurate identification and evaluation of lymph nodes by CT images is of great significance for disease diagnosis, treatment, and prognosis. PURPOSE: To assess the lymph nodes' segmentation, size, and station by artificial intelligence (AI) for unenhanced chest CT images and evaluate its value in clinical scenarios. MATERIAL AND METHODS: This retrospective study proposed an end-to-end Lymph Nodes Analysis System (LNAS) consisting of three models: the Lymph Node Segmentation model (LNS), the Mediastinal Organ Segmentation model (MOS), and the Lymph Node Station Registration model (LNR). We selected a healthy chest CT image as the template image and annotated 14 lymph node station masks according to the IASLC to build the lymph node station mapping template. The exact contours and stations of the lymph nodes were annotated by two junior radiologists and reviewed by a senior radiologist. Patients aged 18 and above, who had undergone unenhanced chest CT and had at least one suspicious enlarged mediastinal lymph node in imaging reports, were included. Exclusions were patients who had thoracic surgeries in the past 2 weeks or artifacts on CT images affecting lymph node observation by radiologists. The system was trained on 6725 consecutive chest CTs that from Tianjin Medical University General Hospital, among which 6249 patients had suspicious enlarged mediastinal lymph nodes. A total of 519 consecutive chest CTs from Qilu Hospital of Shandong University (Qingdao) were used for external validation. The gold standard for each CT was determined by two radiologists and reviewed by one senior radiologist. RESULTS: The patient-level sensitivity of the LNAS system reached of 93.94% and 92.89% in internal and external test dataset, respectively. And the lesion-level sensitivity (recall) reached 89.48% and 85.97% in internal and external test dataset. For man-machine comparison, AI significantly apparently shortened the average reading time (p < 0.001) and had better lesion-level and patient-level sensitivities. CONCLUSION: AI improved the sensitivity lymph node segmentation by radiologists with an advantage in reading time.

Profiling of Volatile Compounds in 'Muscat Hamburg' Contaminated with Aspergillus carbonarius before OTA Biosynthesis Based on HS-SPME-GC-MS and DLLME-GC-MS.

Aspergillus carbonarius is known to produce the carcinogenic ochratoxin A (OTA) in grapes. The metabolism process before OTA biosynthesis influences the content and composition of the volatile compounds in grapes. In this study, a self-established method based on QuEChERS coupled with high-performance liquid chromatography-fluorescence detection (HPLC-FLD) was used to determine the OTA levels during a seven-day contamination period. The results showed that OTA was detected on the second day after contamination with A. carbonarius. Thus, the first day was considered as the critical sampling timepoint for analyzing the volatiles in grapes before OTA biosynthesis. Additionally, the volatile compounds in grapes were analyzed using headspace solid-phase microextraction gas chromatography-mass spectrometry (HS-SPME-GC-MS) and dispersive liquid-liquid microextraction gas chromatography-mass spectrometry (DLLME-GC-MS). The corresponding data were evaluated via multivariate data analysis using projection methods, including PCA and OPLS-DA. The results indicated significant differences in the nine volatile compounds in grapes contaminated with A. carbonarius before OTA biosynthesis. The results of the Pearson correlation analysis showed positive correlations between ethyl acetate, styrene, 1-hexanol and OTA; (E)-2-hexenal and nerolic acid were negatively correlated with OTA. Overall, these findings provide a theoretical basis for the early prediction of OTA formation in grape and grape products using GC-MS technology.

Differential regulation of physicochemical properties and myofibrillar protein degradation of yak meat by interactions between reactive oxygen species and reactive nitrogen species during postmortem aging.

BACKGROUND: This study aimed to explore how interactions between reactive oxygen species (ROS) and reactive nitrogen species (RNS) affect oxidative properties, nitrosative properties, and myofibrillar protein degradation during postmortem aging of yak meat. RESULTS: Yak longissimus dorsi was incubated with saline, ROS activator (H2O2)/inhibitor N-Acetyl-L-cysteine (NAC) and RNS activator S-Nitrosoglutathione (GSNO)/inhibitor L-NAME hydrochloride (L-NAME) combined treatments at 4 °C for 12, 24, 72, 120, and 168 h. The results indicated that regardless of whether RNS was activated or inhibited, activated ROS played a dominant role in myofibrillar protein degradation by oxidative modification to increase carbonyl content, disulfide bonds, surface hydrophobicity, and dimerized tyrosine while decreasing sulfhydryl content, thereby degrading nebulin, titin, troponin-t and desmin. Notably, the Warner-Bratzler shear force (WBSF) of the H2O2 + L-NAME group was the smallest, whereas that of the NAC + GSNO group was smaller than that of the NAC + L-NAME group. CONCLUSION: These findings provide new insights into meat tenderization patterns through the interaction between ROS and RNS. © 2024 Society of Chemical Industry.

Unraveling False Positives in Unsupervised Defect Detection Models: A Study on Anomaly-Free Training Datasets.

Unsupervised defect detection methods have garnered substantial attention in industrial defect detection owing to their capacity to circumvent complex fault sample collection. However, these models grapple with establishing a robust boundary between normal and abnormal conditions in intricate scenarios, leading to a heightened frequency of false-positive predictions. Spurious alerts exacerbate the work of reconfirmation and impede the widespread adoption of unsupervised anomaly detection models in industrial applications. To this end, we delve into the sole available data source in unsupervised defect detection models, the unsupervised training dataset, to introduce a solution called the False Alarm Identification (FAI) method aimed at learning the distribution of potential false alarms using anomaly-free images. It exploits a multi-layer perceptron to capture the semantic information of potential false alarms from a detector trained on anomaly-free training images at the object level. During the testing phase, the FAI model operates as a post-processing module applied after the baseline detection algorithm. The FAI algorithm determines whether each positive patch predicted by the normalizing flow algorithm is a false alarm by its semantic features. When a positive prediction is identified as a false alarm, the corresponding pixel-wise predictions are set to negative. The effectiveness of the FAI method is demonstrated by two state-of-the-art normalizing flow algorithms on extensive industrial applications.

Perceived health-care quality in China: a comparison of second- and third-tier hospitals.

OBJECTIVES: To evaluate disparity in service quality between second- and third-tier hospitals and explore factors that affect patients' perception of service quality in China. DESIGN: Cross sectional study. SETTING: Twelve hospitals in China. PARTICIPANTS: 5714 patients. INTERVENTION: None. MAIN OUTCOME MEASURE: Total score of the SERVQUAL scale and each of its five dimensions. RESULTS: Patients from third-tier hospitals rated significantly higher scores overall and in all the five dimensions of the SERVQUAL scale. Those with lower education, urban residents and those who had higher degree of life satisfaction and attention paid to health perceived higher service quality. Inpatients perceived higher service quality compared with outpatients. CONCLUSION: We found a significant gap in patient's perceived service quality between second- and third-tier hospitals in China. A variety of demographic and personality factors were found to significantly influence patient's perceived service quality.

Glycosylation of Volatile Phenols in Grapes following Pre-Harvest (On-Vine) vs. Post-Harvest (Off-Vine) Exposure to Smoke.

Taint in grapes and wine following vineyard exposure to bushfire smoke continues to challenge the financial viability of grape and wine producers worldwide. In response, researchers are studying the chemical, sensory and physiological consequences of grapevine smoke exposure. However, studies involving winemaking trials are often limited by the availability of suitable quantities of smoke-affected grapes, either from vineyards exposed to smoke or from field trials involving the application of smoke to grapevines. This study compared the accumulation of volatile phenol glycosides (as compositional markers of smoke taint) in Viognier and Cabernet Sauvignon grapes exposed to smoke pre- vs. post-harvest, and found post-harvest smoke exposure of fruit gave similar levels of volatile phenol glycosides to fruit exposed to smoke pre-harvest. Furthermore, wines made from smoke-affected fruit contained similar levels of smoke-derived volatile phenols and their glycosides, irrespective of whether smoke exposure occurred pre- vs. post-harvest. Post-harvest smoke exposure therefore provides a valid approach to generating smoke-affected grapes in the quantities needed for winemaking trials and/or trials that employ both chemical and sensory analysis of wine.

Comprehensive identification and analysis of DELLA genes throughout the plant kingdom.

BACKGROUND: DELLAs play key roles in plant gibberellin signaling pathways and are generally important in plant development and growth. However, DELLAs in many plant taxa have not yet been systematically analyzed. RESULTS: In our study, we searched for DELLA genes across 58 green plant genomes and found 181 DELLAs. Structure analysis showed some DELLA domains do not contain "D-E-L-L-A" sequences and instead contain similar domains, including DGLLA and DSLLH domains. "VHYNP" motifs in plant DELLAs comprise 23 types of sequences, while some DELLAs did not contain GRAS domains. In grape, we found that the DELLA protein GSVIVT01015465001 contains an F-box domain, while apple DELLA proteins MDP0000220512 and MDP0000403162 contain a WW domain and a BCIP domain, respectively. These DELLAs can be divided into 22 homologous groups and 17 orthologous groups, and 35 paralogous genes were identified. In total, 35 positively selected genes (PSGs) and 121 negatively selected genes (NSGs) were found among DELLAs based on selective pressure analysis, with an average Ks of NSGs that was significantly higher than that of PSGs (P < 0.05). Among the paralogous groups, CBI and Fop were significantly positively correlated with GC, GC1, GC2, GC12, and GC3, while CAI was significantly positively correlated with GC, GC1, GC12, and GC. The paralogous groups with ω values exceeding 1 had significantly higher Ka values. We also found some paralogous groups with ω values exceeding 1 that differed in their motifs. CONCLUSIONS: This study provides helpful insights into the evolution of DELLA genes and offers exciting opportunities for the investigation of DELLA functions in different plants.

Determination of sulfa antibiotic residues in river and particulate matter by field-amplified sample injection-capillary zone electrophoresis.

In the present research, field-amplified sample injection-CZE (FASI-CZE) coupled with a diode array detector was established to determine trace level sulfa antibiotic. Sulfathiazole, sulfadiazine, sulfamethazine, sulfadimethoxine, sulfamethoxazole, and sulfisoxazole were selected as analytes for the experiments. The background electrolyte solution consisted of 70.0 mmol/L borax and 60.0 mmol/L boric acid (including 10% methanol, pH 9.1). The plug was 2.5 mmol/L borax, which was injected into the capillary at a pressure of 0.5 psi for 5 s. Then the sample was injected into the capillary at an injection voltage of -10 kV for 20 s. The electrophoretic separation was carried out under a voltage of +19 kV. The capillary temperature was maintained at 20˚C throughout the analysis, and six sulfonamides were completely separated within 35 min. Compared with pressure injection-CZE, the sensitivity of FASI-CZE was increased by 6.25-10.0 times, and the LODs were reduced from 0.2-0.5 to 0.02-0.05 µg/mL. The method was applied to the determination of sulfonamides in river water and particulate matter samples. The recoveries were 78.59-106.59%. The intraday and interday precisions were 2.89-7.35% and 2.77-7.09%, respectively. This provides a simpler and faster method for the analysis of sulfa antibiotic residues in environmental samples.

Detection of caffeine and its main metabolites for early diagnosis of Parkinson's disease using micellar electrokinetic capillary chromatography.

Caffeine (CA) is a common xanthine alkaloid found in tea leaves, coffee beans, and other natural plants, and is the most widely used psychotropic substance in the world. Accumulating evidence suggests that low plasma levels of CA and its metabolites may serve as reliable diagnostic markers for early Parkinson's disease (PD) patients. In this study, we demonstrated a new MEKC method for determining CA and its three main downstream metabolites, paraxanthine (PX), theobromine (TB), and theophylline (TP), in human plasma. Plasma samples were collected, and analyzed using MEKC, after SPE. The running buffer was composed of 35 mM phosphate, pH of 10.5, and 25 mM SDS. The separation voltage was 15 kV and the detection wavelength was at 210 nm. Under the optimum conditions, four distinct analytes were completely separated and detected in less than 12 min. Method limits of detection were as low as 7.5 ng/mL for CA, 5.0 ng/mL for TB, and 4.0 ng/mL for both PX and TP. The recoveries were between 88.0% and 105.9%. This method was successfully applied to 27 human plasma samples. The results indicate that the plasma concentrations of the four analytes are significantly lower in patients with early PD than in control subjects (p < 0.05). The area under curve was improved to 0.839 when CA and its three main metabolites were included, suggesting that MEKC testing of CA, TP, TB, and PX may serve as a potential method for early diagnosis of PD.

LncRNA LINC00261 overexpression suppresses the growth and metastasis of lung cancer via regulating miR-1269a/FOXO1 axis.

BACKGROUND: LncRNAs are key regulators in cancer. The current study explored the role of lncRNA LINC00261 (LINC00261) in lung cancer (LC). METHODS: Expression of LINC00261 in LC tissues and cells was determined by quantitative real-time polymerase chain reaction (qRT-PCR). Pearson's Chi square test and Kaplan-Meier analysis were performed to evaluate the correlations between LINC00261 expression and clinical characteristics, and overall survival time. A549 and SPC-A1 cells were transfected with LINC00261 overexpression plasmid, cell viability, cell number, and apoptosis were detected by CCK-8 assay, colony formation, and flow cytometry. Moreover, wound-healing and transwell assay were performed to detect cell metastasis and invasion. Expressions of proteins related to cell proliferation and metastasis were determined by Western blot. Xenograft was constructed, and tumor size and weight were measured and the effects of LINC00261 overexpression on tumor growth were detected. Bioinformatics analysis, dual-luciferase reporter assay, qRT-PCR, correlation analysis, and functional rescue experiments were conducted on clinical cases and LC cells to explore the molecular mechanism of LINC00261 in LC. RESULTS: In LC, LINC00261 expression was down-regulated, and was associated with more advanced TNM stage, metastasis and a shorter survival time. LINC00261 overexpression inhibited the growth and metastasis of LC cells in vitro and tumor growth in vivo. Furthermore, miR-1269a directly interacted with LINC00261 and FOXO1. The expressions of miR-1269a and FOXO1 were dysregulated by LINC00261 in LC. Additionally, miR-1269a promoted the progression of LC through targeting FOXO1. CONCLUSIONS: Down-regulation of LINC00261 expression has a prognostic value in LC, and overexpression LINC00261 inhibits LC progression via targeting miR-1269a/FOXO1 axis.

Determination of monoamine neurotransmitters and metabolites by high-performance liquid chromatography based on Ag(III) complex chemiluminescence detection.

A novel, simple and efficient chemiluminescence system has been developed for the determination of monoamine neurotransmitters and metabolites. By using the Ag (III)-luminol chemiluminescence system as a detector, a high performance liquid chromatography chemiluminescence method (HPLC-CL) was established and used to detect seven monoamine neurotransmitters. Under the optimized conditions, the detection limits (3S/N) of epinephrine (E), levodopa (l-DOPA), dopamine (DA), serotonin (5-HT), 3-methoxy-4-hydroxyphenylglycol (MHPG), 3,4-dihydroxyphenylacetic acid (DOPAC) and 5-hydroxypentylacetic acid (5-HIAA) were 20.0 µg dm-3,15.0 µg dm-3, 15.0 µg dm-3, 8.0 µg dm-3, 2.0 µg dm-3, 2.0 µg dm-3 and 3.0 µg dm-3, respectively. Moreover, they were well within the linear range of 50-1000 µg dm-3, 50-1000 µg dm-3, 50-1000 µg dm-3, 25-1000 µg dm-3, 5-25 µg dm-3, 5-25 µg dm-3 and 10-30 µg dm-3, respectively. The average recovery varied between 84.82% and 110.4%. The method has the attributes of simplicity, high sensitivity, and high efficiency. The sensitization and inhibition mechanisms for luminol-[Ag(HIO6)2]5-- analytes CL system were proposed by CL spectra and free-radical capture experiment.

Fault Diagnosis of Rolling Bearings Based on a Residual Dilated Pyramid Network and Full Convolutional Denoising Autoencoder.

Intelligent fault diagnosis algorithm for rolling bearings has received increasing attention. However, in actual industrial environments, most rolling bearings work under severe working conditions of variable speed and strong noise, which makes the performance of many intelligent fault diagnosis methods deteriorate sharply. In this regard, this paper proposes a new intelligent diagnosis algorithm for rolling bearing faults based on a residual dilated pyramid network and full convolutional denoising autoencoder (RDPN-FCDAE). First, a continuous wavelet transform (CWT) is used to convert original vibration signals into time-frequency images. Secondly, a deep two-stage RDPN-FCDAE model is constructed, which is divided into three parts: encoding network, decoding network and classification network. In order to obtain efficient expression of data denoising feature of encoding network, time-frequency images are first input into the encoding-decoding network for unsupervised pre-training. Then pre-trained coding network and classification network are combined into residual dilated pyramid full convolutional network (RDPFCN) for parameter fine-tuning and testing. The proposed method is applied to bearing vibration datasets of test rig with different speeds and noise modes. Compared with representative machine learning and deep learning method, the results show that the algorithm proposed is superior to other methods in diagnostic accuracy, noise robustness and feature segmentation ability.

Small RNA and degradome deep sequencing reveal respective roles of cold-related microRNAs across Chinese wild grapevine and cultivated grapevine.

BACKGROUND: Chinese wild grapevine (Vitis amurensis) has remarkable cold stress tolerance, exceeding that of the common cultivated grapevine (Vitis vinifera L.). RESULT: Here, we surveyed the expression dynamics of microRNAs (miRNAs) across Chinese wild grapevine (cv. Beibinghong) and cultivated grapevine (cv. Cabernet Sauvignon) under cold stress using high-throughput sequencing. We identified 186 known miRNAs in cultivated grape and 427 known miRNAs in Beibinghong. Of the identified miRNAs, 59 are conserved miRNAs orthologous in Cabernet Sauvignon and Beibinghong. In addition, 105 and 129 novel miRNAs were identified in Cabernet Sauvignon and Beibinghong, respectively. The expression of some miRNAs was related to cold stress both in Cabernet Sauvignon and Beibinghong. Many cold-related miRNAs in Cabernet Sauvignon and Beibinghong were predicted to target stress response-related genes such as MYB, WRKY, bHLH transcription factor genes, and heat shock protein genes. However, the expression tendency under cold treatment of many of these miRNAs was different between Cabernet Sauvignon and Beibinghong. Different modes of expression of cultivated and Chinese wild grape miRNAs were indicated in key pathways under cold stress by degradome, target prediction, GO, and KEGG analyses. CONCLUSION: Our study indicated three likely reasons that led to the different cold stress tolerance levels of Cabernet Sauvignon and Beibinghong. Specifically, there may be (1) differential expression of orthologous miRNAs between cultivated grapevine and Chinese wild grape; (2) species-specific miRNAs or target genes; or (3) different regulatory models of miRNAs in cultivated and Chinese wild grape in some key pathways.

L. pseudomesenteroides and L. johnsonii isolated from yaks in Tibet modulate gut microbiota in mice to ameliorate enteroinvasive Escherichia coli-induced diarrhea.

Enteroinvasive Escherichia coli (EIEC) are well-known food-borne pathogens that cause animal intestinal diseases. Lactobacillus is believed to inhibit intestinal pathogens and maintain a healthy gut microbiota. This study aimed to investigate the effects of pre-supplementation of Lactobacillus from yaks (4500m) to prevent the clinical symptoms and the improvement of the disordered flora caused by E. coli infection. Forty healthy mice were randomized to four study groups (n = 10); Leuconostoc pseudomesenteroides (LP1), Lactobacillus johnsonii (LJ1), blank control, and control groups. Mice in the LP1, LJ1, and control groups were intraperitoneally challenged with EIEC O124 (1 × 109 CFU) on day 23. After two days, the mice in control group were recorded for high mortality. The diarrhea in LP1 and LJ1 groups was much lower than that in the control group, and no death was recorded. In histopathology, pre-supplementation of LJ1 and LP1 relieved the damage to the liver, spleen and duodenum caused by E. coli. In addition, the normal intestinal microecology was also affected by infection of EIEC, including an increase in relative abundance of Proteobacteria. At the same time, the beneficial bacteria were increased and harmful bacteria were decreased in different intestinal segments of the LJ1 and LP1 groups compared to the control group. In conclusion, pre-supplementation of LP1 and LJ1 can mitigate EIEC-induced intestinal flora dysbiosis and can also reduce EIEC-associated diarrhea.

High-Speed Railway Intruding Object Image Generating with Generative Adversarial Networks.

Foreign object intrusion is a great threat to high-speed railway safety operations. Accurate foreign object intrusion detection is particularly important. As a result of the lack of intruding foreign object samples during the operational period, artificially generated ones will greatly benefit the development of the detection methods. In this paper, we propose a novel method to generate railway intruding object images based on an improved conditional deep convolutional generative adversarial network (C-DCGAN). It consists of a generator and multi-scale discriminators. Loss function is also improved so as to generate samples with a high quality and authenticity. The generator is extracted in order to generate foreign object images from input semantic labels. We synthesize the generated objects to the railway scene. To make the generated objects more similar to real objects, on scale in different positions of a railway scene, a scale estimation algorithm based on the gauge constant is proposed. The experimental results on the railway intruding object dataset show that the proposed C-DCGAN model outperforms several state-of-the-art methods and achieves a higher quality (the pixel-wise accuracy, mean intersection-over-union (mIoU), and mean average precision (mAP) are 80.46%, 0.65, and 0.69, respectively) and diversity (the Fréchet-Inception Distance (FID) score is 26.87) of generated samples. The mIoU of the real-generated pedestrian pairs reaches 0.85, and indicates a higher scale of accuracy for the generated intruding objects in the railway scene.

Polypyrrole-Modified Nylon 6 Nanofibers as Adsorbent for the Extraction of Two ß-Lactam Antibiotics in Water Followed by Determination with Capillary Electrophoresis.

A solid phase membrane adsorbent-a nylon 6 nanofibers membrane coated by polypyrrole (PPy-PA6-NFsM)-was firstly synthesized and used for extraction of two ß-lactam antibiotics (oxacillin and cloxacillin) in urban river water. Then the analytes were detected by capillary electrophoresis with a diode array detector (CE-DAD). The synthesized nanofibers membrane was characterized by scanning electron microscopy and a Fourier transform infrared spectrometer. The experimental conditions were optimized, including the amount used of PPy-PA6-NFsM, pH of the sample solutions, adsorption volume, and desorption conditions. Under the optimal extraction and separation conditions, the detection limits were found to be 2.0 ng/mL for both oxacillin and cloxacillin. The proposed method was applied to the determination of the two ß-lactams in water samples of an urban river. The recoveries of these two ß-lactams were found to be in the range 84.2-96.4%, demonstrating that PPy-PA6-NFsM has a high extraction capability for these two antibiotics. The relative standard deviations, ranging from 2.26% to 5.29% for intraday measurements and from 2.38% to 7.02% for inter-day determinations, were derived respectively.

Effect of the treatment-before-deposit policy on trust in physicians and perceived service quality among patients in 12 hospitals in China.

This study examined effects of the treatment-before-deposit policy on Chinese patients' trust in physicians and perceived service quality. This study included 3313 patients recruited from 12 hospitals in China. The research team used cross-sectional survey to examine Chinese patients' experience with the treatment-before-deposit policy, perceived service quality, and trust in their physicians. Using mediation analysis, we estimated direct and indirect effects of the treatment-before-deposit policy on patients' perceived service quality and trust in their physicians. Patients who benefitted from the treatment-before-deposit policy reported greater service quality and higher trust in their physicians. The impacts of whether patients benefitted from the policy on trust in physicians were fully mediated by perceived service quality with statistically significant indirect effect. The results support the hypothesis that the treatment-before-deposit policy improves patients' perceived service quality and trust in physicians.

Sensory Eye Dominance in Treated Anisometropic Amblyopia.

Amblyopia results from inadequate visual experience during the critical period of visual development. Abnormal binocular interactions are believed to play a critical role in amblyopia. These binocular deficits can often be resolved, owing to the residual visual plasticity in amblyopes. In this study, we quantitatively measured the sensory eye dominance in treated anisometropic amblyopes to determine whether they had fully recovered. Fourteen treated anisometropic amblyopes with normal or corrected to normal visual acuity participated, and their sensory eye dominance was assessed by using a binocular phase combination paradigm. We found that the two eyes were unequal in binocular combination in most (11 out of 14) of our treated anisometropic amblyopes, but none of the controls. We concluded that the treated anisometropic amblyopes, even those with a normal range of visual acuity, exhibited abnormal binocular processing. Our results thus suggest that there is potential for improvement in treated anisometropic amblyopes that may further enhance their binocular visual functioning.

Determination of Sulfonamide Residues in Food by Capillary Zone Electrophoresis with On-Line Chemiluminescence Detection Based on an Ag(III) Complex.

The presence of sulfonamide (SA) residues in foods is largely due to the raising of animals with sulfonamide antibiotics added or polluted feedstuff. In this paper, a sensitive method was developed for the determination of the residues of three sulfonamides in animal-derived food; the SAs include sulfadimidine (SDD), sulfadiazine (SDZ), and sulfathiazole (STZ). The method is based on capillary zone electrophoresis (CE) with online chemiluminescence (CL) detection, using an Ag(III) complex as an oxidant. These SAs have an inhibiting effect on the Ag(III)-luminol CL reaction. The electrophoretic buffer is 12.0 mM sodium borate. Under a set of optimized conditions, the linear ranges for the detections were found to be 10.0-200 µg·mL-1 for SDD and SDZ, and 2.0-50.0 µg·mL-1 for STZ. The detection limits were 2.75, 3.14, and 0.65 µg·mL-1 for SDD, SDZ, and STZ, respectively. Relative standard deviations (RSD) for the peak heights were between 2.1% and 2.8% (n = 7). The proposed method was used in the analysis of the SAs in samples from pork meat, chicken meat, and milk, showing satisfactory detection results. A reaction mechanism was also proposed for the Ag(III)-luminol-SA CL reactions. The method has potential applications for the monitoring of residue levels of the three SAs in food, providing food safety data.

Capillary electrophoresis chemiluminescence assay of naphthol isomers in human urine and river water using Ni(IV) complex-luminol system.

A capillary electrophoresis method involving online indirect chemiluminescence (CL) detection was used to determine naphthol (NAP) isomers. The method was based on the quenching effect of 1- and 2-NAP on a new CL reaction of luminol with Ni(IV) complex in an alkaline medium. Separation was conducted with a 25.0 mM sodium borate buffer containing 0.8 mmol/L luminol. Under optimized conditions, 1- and 2-NAP were baseline separated and detected in less than 8 min. The limits of detection of 1- and 2-NAP were 3.1 and 2.7 µg/L, respectively (S/N = 3), with a linear range of 4.0-80.0 µg/L (r > 0.995). Analysis of real samples demonstrated that the spiked recoveries were in the range of 89.2-107.5% (n = 3). The proposed method was successfully used to determine 1- and 2-NAP contents in three environmental water samples and 14 human urine samples. No derivatization or tedious pretreatment was required in the analysis. The proposed method is a potential approach for routine tests of naphthol isomers in a facile CE-CL system.