Integrated metabolomic and transcriptomic analyses provide insights into regulation mechanisms during bulbous stem development in the Chinese medicinal herb plant, Stephania kwangsiensis.

BACKGROUND: Stephania kwangsiensis Lo (Menispermaceae) is a well-known Chinese herbal medicine, and its bulbous stems are used medicinally. The storage stem of S. kwangsiensis originated from the hypocotyls. To date, there are no reports on the growth and development of S. kwangsiensis storage stems. RESULTS: The bulbous stem of S. kwangsiensis, the starch diameter was larger at the stable expanding stage (S3T) than at the unexpanded stage (S1T) or the rapidly expanding stage (S2T) at the three different time points. We used ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) and Illumina sequencing to identify key genes involved in bulbous stem development. A large number of differentially accumulated metabolites (DAMs) and differentially expressed genes (DEGs) were identified. Based on the differential expression profiles of the metabolites, alkaloids, lipids, and phenolic acids were the top three differentially expressed classes. Compared with S2T, significant changes in plant signal transduction and isoquinoline alkaloid biosynthesis pathways occurred at both the transcriptional and metabolic levels in S1T. In S2T compared with S3T, several metabolites involved in tyrosine metabolism were decreased. Temporal analysis of S1T to S3T indicated the downregulation of phenylpropanoid biosynthesis, including lignin biosynthesis. The annotation of key pathways showed an up-down trend for genes and metabolites involved in isoquinoline alkaloid biosynthesis, whereas phenylpropanoid biosynthesis was not completely consistent. CONCLUSIONS: Downregulation of the phenylpropanoid biosynthesis pathway may be the result of carbon flow into alkaloid synthesis and storage of lipids and starch during the development of S. kwangsiensis bulbous stems. A decrease in the number of metabolites involved in tyrosine metabolism may also lead to a decrease in the upstream substrates of phenylpropane biosynthesis. Downregulation of lignin synthesis during phenylpropanoid biosynthesis may loosen restrictions on bulbous stem expansion. This study provides the first comprehensive analysis of the metabolome and transcriptome profiles of S. kwangsiensis bulbous stems. These data provide guidance for the cultivation, breeding, and harvesting of S. kwangsiensis.

Establishment of diabetes mellitus model using Bombyx mori silkworms in a low-temperature environment.

Due to the high prevalence of diabetes mellitus, researchers have conducted numerous experimental animal studies. However, the mammalian diabetes model is cumbersome and expensive to operate, while the cheap and simple common silkworm diabetes model has the disadvantage of a short cycle time. Since the growth of silkworms is greatly affected by environmental factors, we extended the five-age cycle of silkworms by lowering the ambient temperature to establish a novel low-temperature silkworm diabetes model. Our goal was to determine whether the low-temperature feeding of a high-sugar diet to silkworms could serve as an effective animal model for diabetes. Also, we aimed to resolve certain issues concerning the normal temperature silkworm diabetes model, such as the short time frame for experiments and erratic fluctuations in blood sugar levels. Silkworms weighing between 0.9 and 1.0 g at the beginning of the fifth instar were selected, and we created diabetic silkworms by feeding mulberry leaves containing 4% glucose daily in a 16-20°C environment. When the silkworms were kept at a cooler temperature, the fifth instar stage lasted for an additional 9-11 days. In the model group, 83.3% of the silkworms had blood glucose levels greater than 7.8 mmol/L, while the total prevalence of diabetic silkworms was 89.8%. Moreover, JNK phosphorylation expression rose in the model group, while PI3K expression fell. Additionally, the JNK and PI3K signaling pathway expressions matched diabetic signals. Therefore, using silkworms to create a diabetes model in a cool environment is a straightforward and cost-effective approach to studying diabetes in animals.

Identification of Characteristic Genes and Immune Cell Infiltration Signatures in Chronic Obstructive Pulmonary Disease.

Chronic obstructive pulmonary disease (COPD) is a lung disease caused by limited airflow that leads to difficulty breathing. It is a major chronic disease that affects human quality of life and even endangers life. However, the exact cause of COPD is still unclear. The present study aimed to identify characteristic genes in COPD, assess the level of immune cell infiltration in COPD samples, and explore the association between characteristic genes and infiltrating immune cells. In this paper, we used dataset GSE76925 to identify 452 differentially expressed genes (DEGs) (including 407 downregulated and 45 upregulated DEGs). Gene Ontology (GO) enrichment analysis showed that the functions mainly include leukocyte migration, protein folding, negative regulation of cell activation, transcription regulator complex, collagen-containing extracellular matrix, RNA polymerase II transcription regulator complex, guanyl nucleotide binding, guanyl ribonucleotide binding, ubiquitin protein ligase binding, etc. In the Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis, pathways identified by DEGs mainly focused on Basal transcription factors, Arachidonic acid metabolism, Nucleocytoplasmic transport, Glutamatergic synapse, Ether lipid metabolism, alpha-Linolenic acid metabolism, etc. Next, we constructed a weighted gene co-expression network, identified six gene modules, found that the module with the highest correlation was the MEturquoise, and obtained 51 hub module genes. Further, 43 overlapping genes were obtained after the intersection of 452 DEGs and 51 hub genes in MEturquoise module, and seven characteristic DEGs (C-DEGs) (LOC649214, LOC440563, LOC643431, LOC642585, KRT18P17, LOC648057 and UBASH3B) were identified by the Least absolute shrinkage and selection operator (LASSO) regression method. In addition, we assessed the infiltration of 28 immune cells in 111 COPD samples and 40 NC samples, calculated and visualized the correlation between the expression of 7 C-DEGs and the infiltration level of 28 immune cells. These results will contribute to our further understanding of the molecular immunopathogenesis of COPD and have potential reference value for the development of molecular drug targets in the future.

Prognostic value of baseline C-reactive protein in diffuse large B-cell lymphoma: a systematic review and meta-analysis.

Background: C-reactive protein (CRP) is an inflammatory marker of great significance for progression and prognosis of diffuse large B-cell lymphoma (DLBCL). However, previous studies reported the inconsistent findings of the relationship between CRP levels and survival in DLBCL patients. This meta-analysis was performed to investigate the predictive value of baseline CRP in the prognosis of DLBCL. Methods: Relevant studies on baseline CRP and prognosis of DLBCL were searched from PubMed, Web of Science, China National Knowledge Infrastructure (CNKI), Wanfang Data Knowledge Service Platform, and other databases. The search time was from establishment of the database to December 2022. The studies that reported the baseline CRP level, DLBCL confirmed by pathology, data on the relationship between CRP and overall survival (OS) or progression-free survival (PFS), and published in English or Chinese were included in this meta-analysis. No evidence showed the risk of bias of the included studies. Random-effects meta-analysis were conducted to calculate hazard ratio (HR). Stata15.0 software was used for the meta-analysis. Results: A total of 11 studies with 2,314 patients were included. All included studies were of high quality. The result of prognosis in patients with CRP and DLBCL was HR =2.48 [95% confidence interval (CI): 1.52 to 4.07]. The subgroup analysis showed that the risk of death was higher in both groups (HR =2.58, 95% CI: 2.10 to 3.18, random effects model I2=39.7%). There was a significant difference between group 1 and group 2 (P=0.000). Conclusions: Current evidence suggests that baseline CRP is a potential predictor of DLBCL patients and has potential prognostic value in clinical practice, improving the survival rate and quality of life of DLBCL patients. Additionally, OS appears to be strongly influenced by potential country specific differences, which may be related to racial differences and specific lifestyles.

IQGAP1 promotes mitochondrial damage and activation of the mtDNA sensor cGAS-STING pathway to induce endothelial cell pyroptosis leading to atherosclerosis.

Atherosclerosis (AS) is the most common cardiovascular disease and has limited therapeutic options. IQ motif-containing GTPase-activating protein 1 (IQGAP1) is an important scaffolding protein regulating mitochondrial function influencing endothelial cell activity. Evidence suggests that mitochondrial damage can lead to leakage of mtDNA into the cytoplasm to activate the DNA sensor cGAS-STING to mediate pyroptosis. However, whether IQGAP1 induces NLRP3-mediated endothelial cell pyroptosis by regulating mitochondrial function and activating the DNA sensor cGAS-STING, and its underlying mechanisms remain unclear. In vivo, ApoE-/- C57BL/J and Ldlr-/- C57BL/J mice were pre-injected with adeno-associated virus (AAV) by the tail vein to specifically silence IQGAP1 expression and were fed a high-fat diet (HFD) for 12 weeks. IQGAP1 knockdown reduced mtDNA release and decreased the expression of DNA receptors and pyroptosis-related molecules as determined by immunohistochemistry and immunofluorescence. In vitro, palmitic acid (0.3 mmol/L) was incubated with human umbilical vein endothelial cells (HUVECs) for 24 h. Overexpression of IQGAP1 in HUVECs, flow cytometry, and mitochondrial superoxide staining revealed increased levels of ROS. Moreover, the mitochondrial tracker with dsDNA co-localization showed the release of mtDNA into the cytoplasm increased, which activated the DNA receptor cGAS-STING. Protein blotting and TUNEL staining revealed that IQGAP1 promoted NLRP3-mediated pyroptosis. Furthermore, cGAS or STING small-molecule inhibitors RU.521 or C-176 reverse IQGAP1-promoted HUVECs from undergoing NLRP3-mediated pyroptosis. These results suggest that IQGAP1 promotes oxidative stress and mtDNA release, activates the DNA sensor cGAS-STING, and leads to NLRP3-mediated pyroptosis. The present study provides new insights into the mechanisms underlying AS and identifies new pharmacological targets for treatment.

Application of protein/polysaccharide aerogels in drug delivery system: A review.

Drug delivery systems have emerged as a prominent research focus in the field of drug development, offering enhanced stability and improved bioavailability. Among them, protein (silk, gelatin and whey) or polysaccharide (alginate, chitosan, cellulose, starch, pectin and carrageenan) aerogels derived from natural sources have gained increasing popularity due to their unique advantages, such as cost-effectiveness, flexible preparation, bioactivity, biocompatibility, and biodegradability. However, despite their growing significance, there remains a lack of comprehensive information and ongoing confusion regarding the application of protein/polysaccharide aerogels in drug delivery system. Hence, the objective of this review was to provide a comprehensive review of the research progress in protein/polysaccharide aerogels for drug delivery systems from the perspective of aerogels category, synthesis strategy, drug-loading method, performance characteristic and release mechanism. Furthermore, by consolidating the existing information, we aimed to present our own perspectives and insights on the future development of protein/polysaccharide aerogels in drug delivery system. In conclusion, this comprehensive review served as a valuable resource for researchers and scholars, addressing the current gaps in knowledge and clarifying the complex landscape of protein/polysaccharide aerogels in drug delivery system.

[Effects of propiconazole on physiological and biochemical properties of Panax notoginseng and dietary risk assessment].

To study the residue and dietary risk of propiconazole in Panax notoginseng and the effects on physiological and bioche-mical properties of P. notoginseng, we conducted foliar spraying of propiconazole on P. notoginseng in pot experiments. The physiolo-gical and biochemical properties studied included leaf damage, osmoregulatory substance content, antioxidant enzyme system, non-enzymatic system, and saponin content in the main root. The results showed that at the same application concentration, the residual amount of propiconazole in each part of P. notoginseng increased with the increase in the times of application and decreased with the extension of harvest interval. After one-time application of propiconazole according to the recommended dose(132 g·hm~(-2)) for P. ginseng, the half-life was 11.37-13.67 days. After 1-2 times of application in P. notoginseng, propiconazole had a low risk of dietary intake and safety threat to the population. The propiconazole treatment at the recommended concentration and above significantly increased the malondialdehyde(MDA) content, relative conductivity, and osmoregulatory substances and caused the accumulation of reactive oxygen species in P. notoginseng leaves. The propiconazole treatment at half(66 g·hm~(-2)) of the recommended dose for P. ginseng significantly increased the activities of superoxide dismutase(SOD), peroxidase(POD), and catalase(CAT) in P. notoginseng leaves. The propiconazole treatment at 132 g·hm~(-2) above inhibited the activities of glutathione reductase(GR) and glutathione S-transferase(GST), thereby reducing glutathione(GSH) content. Proconazole treatment changed the proportion of 5 main saponins in the main root of P. notoginseng. The treatment with 66 g·hm~(-2) propiconazole promoted the accumulation of saponins, while that with 132 g·hm~(-2) and above propiconazole significantly inhibited the accumulation of saponins. In summary, using propiconazole at 132 g·hm~(-2) to prevent and treat P. notoginseng diseases will cause stress on P. notoginseng, while propiconazole treatment at 66 g·hm~(-2) will not cause stress on P. notoginseng but promote the accumulation of saponins. The effect of propiconazole on P. notoginseng diseases remains to be studied.

[Retracted] Study of miR-143 expression in stomach cancer.

[This retracts the article DOI: 10.3892/ol.2018.9173.].

Analysis of risk factors and construction of a prediction model for short stature in children.

Background: Short stature in children is an important global health issue. This study aimed to analyze the risk factors associated with short stature and to construct a clinical prediction model and risk classification system for short stature. Methods: This cross-sectional study included 12,504 children aged 6-14 years of age from 13 primary and secondary schools in Pingshan District, Shenzhen. A physical examination was performed to measure the height and weight of the children. Questionnaires were used to obtain information about children and their parents, including sex, age, family environment, social environment, maternal conditions during pregnancy, birth and feeding, and lifestyle. The age confounding variable was adjusted through a 1 : 1 propensity score matching (PSM) analysis and 1,076 children were selected for risk factor analysis. Results: The prevalence of short stature in children aged 6-14 years was 4.3% in the Pingshan District, Shenzhen. The multivariate logistic regression model showed that the influencing factors for short stature were father's height, mother's height, annual family income, father's level of education and parents' concern for their children's height in the future (P < 0.05). Based on the short stature multivariate logistic regression model, a short stature nomogram prediction model was constructed. The area under the ROC curve (AUC) was 0.748, indicating a good degree of discrimination of the nomogram. According to the calibration curve, the Hosmer-Lemesio test value was 0.917, and the model was considered to be accurate. Based on a risk classification system derived from the nomogram prediction model, the total score of the nomogram was 127.5, which is considered the cutoff point to divides all children into low-risk and high-risk groups. Conclusion: This study analyzed the risk factors for short stature in children and constructed a nomogram prediction model and a risk classification system based on these risk factors, as well as providing short stature screening and assessment individually.

The surgical strategy of hormonally active primary cardiac paraganglioma sarcoma: A case report.

Cardiac paraganglioma is a kind of rare neuroendocrine tumor characterized by the persistent secretion of catecholamines. Under excessive exposure of catecholamines, some atypical symptoms are presented, including hypertension, arrhythmias, and headache. The case of surgical treatment of a 28-year-old woman with primary cardiac paraganglioma is presented for experience sharing and surgical skill improvements.

The Surgical Strategy for Progressive Dilatation of Aortic Root and Aortic Regurgitation After Repaired Tetralogy of Fallot: A Case Report.

It has been found that postoperative progressive dilatation of aortic root is not rare for adult patients with repaired Tetralogy of Fallot (TOF), which leads to severe aortic regurgitation or even fatal dissection. Therefore, clinically, surgical treatment for both regurgitated aortic valve and dilated root is needed based on preoperative assessments and individual treatment strategies.

Rapid determination and dietary intake risk assessment of 249 pesticide residues in Panax notoginseng.

UPLC-MS/MS and GC-MS/MS were used to establish a method to simultaneously determine various pesticide residues in Panax notoginseng. Results showed that the limits of detection of 249 pesticides were all 5-10 µg/kg. The detection rate of pesticides in 121 P. notoginseng samples was 93.39%, and 19 pesticides were detected. According to the US Code of Federal Regulations, the Chinese Pharmacopoeia recommended algorithm, and the Japanese "positive list system", the pass rates of pesticide residues were 100%, 99.17%, and 89.26%, respectively. The chronic risk quotient (ADI%) and acute risk quotient (ARfD%) of P. notoginseng were 0.00-0.12% and 0.00-0.15%, respectively. In summary, the detection method established in this study can be used for routine analysis of various P. notoginseng pesticide residues. The pesticide residues in the main root samples of P. notoginseng were at a safe level and unlikely pose health risks to consumers.

Internet-like brain hierarchical network model: Alzheimer's disease study as an example.

BACKGROUND AND OBJECTIVE: The modular structure and hierarchy are important topological characteristics in real complex networks such as brain networks on temporal scale. However, there are few studies investigating the hierarchical structure at the spatial scale of brain networks, the application of which still remains to be further studied. METHODS: In this study, a novel model of brain hierarchical network based on the hierarchical characteristic of Internet topology is proposed for the first time, which is called Internet-like brain hierarchical network (IBHN). In this model, the whole brain network is partitioned into multiple levels: brain wide area network (Brain-WAN), brain metropolitan network (Brain-MAN), and brain local area network (Brain-LAN). A Brain-MAN is formed by the interconnection of multiple Brain-LANs, and the interconnection of multiple Brain-MANs forms a Brain-WAN. A multivariate analysis method is employed to measure overall functional connectivity between two brain networks at the same network level rather than detecting the change of each node pair's functional connection. Furthermore, we demonstrate the utility of IBHN model with application to a practical case-control study involving 64 patients with Alzheimer's disease and 75 healthy controls. RESULTS: The proposed model identified enhanced functional connectivity (P-value<0.05) at Brain-WAN level and reduced functional connectivity (P-value=0.004) at Brain-LAN level of Alzheimer's disease patients, which can be used as a multi-dimension functional reference for AD's diagnosis. CONCLUSIONS: This study not only provides insight into AD pathophysiology, but also further proves the effectiveness of the proposed IBHN model. In addition, the IBHN model makes it possible to explore the brain's functional organization from multiple dimensions and offers a multi-level perspective for the research of complex brain network.

Specific immunity proteomic profile of the skin mucus of Antarctic fish Chionodraco hamatus and Notothenia coriiceps.

The white-blooded Antarctic icefish is the only known vertebrate lacking oxygen-transporting haemoglobins. Fish skin mucus, as the first line of defence against pathogens, can reflect fish welfare. In this study, we analysed the skin mucus proteome profiles of the two Antarctic fish species, the white-blooded Antarctic icefish, Chionodraco hamatus, and the red-blooded Antarctic fish, Notothenia coriiceps, unfolding the different proteins by liquid chromatography coupled with tandem mass spectrometry isobaric tags for relative and absolute quantitation (iTRAQ) technology. Of the 4444 totally identified proteins, 227 differentially expressed proteins (DEPs) were found in the comparison between C. hamatus and N. coriiceps, of which 121 were upregulated and 106 were downregulated in the icefish. In the Kyoto Encyclopedia of Genes and Genomes pathway annotation, we found two pathways "Legionellosis" and "Complement and coagulation cascades" were significantly enriched, among of which innate immune candidate proteins such as C3, CASP1, ASC, F3 and C9 were significantly upregulated, suggesting their important roles in C. hamatus immune system. Additionally, the DEP protein-protein interaction network analysis and "Response to stress" GO category provided candidate biomarkers for deep understanding of the distinct immune response of the two Antarctic fish underlying the cold adaptation.

Malat-1 expression in bladder carcinoma tissues and its clinical significance.

OBJECTIVE: To investigate the expression of metastasis-associated lung adenocarcinoma transcript 1 (Malat-1) in bladder carcinoma and its relationship with clinicopathological characteristics and prognosis. METHODS: Specimens were collected from 90 patients with bladder carcinoma who underwent urological surgery in our hospital. Twenty patients diagnosed with benign prostatic hyperplasia were selected as the negative control. The expression of Malat-1 was detected by real-time reverse transcription PCR, and its relationship with clinicopathological factors and prognosis was analyzed. RESULTS: The expression of Malat-1 in bladder carcinoma tissues (2.55±0.31) was higher than that in adjacent tissues (1.62±0.42) and normal bladder mucosa tissues (0.84±0.06); the differences were statistically significant (t=13.647 and 27.302, both P<0.001). The high expression rate of Malat-1 in bladder carcinoma tissues (86.67%) was significantly higher than that in adjacent tissues (22.22%) and normal bladder mucosa tissues (5.00%; P=0.000 and 0.000). The high expression rate of Malat-1 was correlated with age, tumor staging, degree of differentiation and lymph node metastasis (P=0.018, 0.000, 0.000, and 0.000). The median survival time and the 1-year, 3-year and 5-year survival rates of patients with high Malat-1 expression were lower than those with low expression of Malat-1 (P=0.006, 0.011, 0.000 and 0.002). High expression of Malat-1 is an independent risk factor for poor overall survival (OS) in bladder cancer patients. CONCLUSION: Overexpression of Malat-1 in bladder carcinoma tissues is associated with malignant biological characteristics and poor prognosis of patients.

Prognosis of radiotherapy in medullary thyroid carcinoma patients without distant metastasis.

BACKGROUND: Medullary thyroid carcinoma (MTC) is an advanced disease with a poor prognosis. Although radiotherapy is widely utilized to treat MTC, it is still controversial. MTC patients without distant metastases have not been investigated to explore indications for adjuvant radiotherapy. This study aims to investigate the impact of radiotherapy on the survival of MTC patients without distant metastases. METHODS: Data of MTC patients without distant metastasis who underwent total thyroidectomy between 2010 and 2015 were obtained from the Surveillance, Epidemiology and End Results (SEER) database. Propensity score matching was performed to analyze the relationship between radiotherapy and cancer-specific survival (CSS). RESULTS: Seventy-four of 718 MTC patients without distant metastases received radiotherapy and underwent total thyroidectomy. A total of 148 patients were screened via propensity score matching analysis. Multivariate Cox regression indicated that factors including age, sex, radiotherapy and chemotherapy were independent predictors of CSS. Based on these factors, MTC patients without distant metastasis were classified into two risk groups using a nomogram and risk classification system. The C-index of the nomogram was 0.791. The calibration curves showed good consistency of CSS between the actual observation and the nomogram prediction, and decision curve analysis (DCA) showed great clinical usefulness of the nomogram. The three-year CSS of the radiotherapy group was 85.3%, and that of the surgery group was 95%. Particularly, compared with the surgery group, the three-year CSS of subgroups of the radiotherapy group, including male patients and those aged >48 years, was decreased. CONCLUSIONS: Radiotherapy results in worse CSS for MTC patients without distant metastases. To maximize benefits, decisions about individual radiotherapy should weigh its advantages and disadvantages.

Performance of Xpert MTB/RIF in diagnosis of lymphatic tuberculosis from fresh and formaldehyde-fixed and paraffin embedded lymph nodes.

In this study, we aimed to assess the performance of Xpert in fresh tissue and formaldehyde-fixed and paraffin embedded (FFPE) specimens from suspected lymphatic tuberculosis for the diagnosis of Mycobacterium tuberculosis (MTB). A total of 52 suspected lymphatic tuberculosis (TB) samples and 10 non-tuberculous lymph nodes samples were collected from outpatients. Using the comprehensive diagnostic criteria as the gold standard, the specificity in fresh and FFPE samples was 100% and the sensitivity was 82.7% and 67.3%, respectively. The majority of fresh tissue specimens had medium and low MTB content, while the low and very low MTB content were noted in 42.9% and 54.3% of FFPE tissue specimens, respectively. There were statistical differences in the MTB content between the two specimen groups detected by Xpert. Three rifampicin-resistant cases in FFPE samples were noted as rifampicin-susceptible in fresh tissue samples. Notably, all three cases with contradictory results of rpoB gene mutation test in fresh and FFPE samples had very low MTB content in FFPE samples. Fresh tissue specimens are more likely to yield Xpert results with high greater MTB content than FFPE specimens from lymphatic TB. The false detection of rpoB mutants is associated with the low bacterial content in the specimens.

Mechanistic Insight into the Chemiluminescent Decomposition of Cypridina Dioxetanone and the Chemiluminescent, Fluorescent Properties of the Light Emitter of Cypridina Bioluminescence.

Cypridina bioluminescence has been increasingly used in bioimaging, bioanalysis, and biomedicine, due to high quantum yield and high signal-to-noise ratio. However, there is still no consensus regarding different aspects of the chemiluminescent mechanism of this system, which impairs the development of new applications. Herein, we have used a theoretical DFT and TD-DFT approach to (i) determine the identity of the dioxetanone species responsible for efficient chemiexcitation and (ii) identify the bioluminescent emitter and determine if light-emission occurs from the fluorescent or chemiluminescent state. Our results demonstrate that upon oxygenation of the imidazopyrazinone scaffold, a dioxetanone with a neutral amide group and a cationic guanidinopropyl group is formed. This species is efficiently chemiexcited (with no obvious charge transfer step) to the corresponding oxyluciferin with a neutral amide and cationic guanidinopropyl groups. After the "dark" chemiluminescent state, this oxyluciferin species is converted into a bright blue-emitting fluorescent state.

[Determination of short-chain chloroparaffins in synthetic surfacing layers used in sports and diluents by solid-phase extraction coupled with gas chromatography-negative chemical ionization-mass spectrometry].

A new method was established to determine short-chain chloroparaffins (SCCPs) in synthetic surfacing layers used in sports and diluents by solid-phase extraction (SPE) coupled with gas chromatography-negative chemical ionization-mass spectrometry (GC-NCI-MS). The analysis conditions for gas chromatography and mass spectrometry were optimized. Then, the samples were extracted by ultrasonication, purified on a Florisil SPE column, monitored in the selective ion monitoring (SIM) scanning mode, and quantified by the external standard method. With this method, a good linear relationship was found over a wide mass concentration range from 0.0501 to 100.17 mg/L, with a linear correlation coefficient (R2) of 0.9995. The detection limit for SCCPs by this method was found to be as low as 0.50 µg/g (i. e. 0.000050%) and the average recoveries for SCCPs spiked in the blank samples varied from 83.2% to 96.3% with relative standard deviations (RSDs) of 1.56%-6.02%. Ten batches of samples were tested and the contents of SCCPs detected in each batch were in the range from 0.016% to 0.55%, which agrees well the European Union limitation requirement for SCCPs. Thus, this method is suitable for qualitative and quantitative analyses of SCCPs in synthetic surfacing layers used in sports and diluents.