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1.
Nat Commun ; 11(1): 379, 2020 Jan 17.
Artigo em Inglês | MEDLINE | ID: mdl-31953408

RESUMO

Insig-2 is an ER membrane protein negatively controlling lipid biosynthesis. Here, we find that Insig-2 is increased in the tissues, including liver, but unaltered in the muscle of gp78-deficient mice. In hepatocytes and undifferentiated C2C12 myoblasts, Insig-2 is ubiquitylated on Cys215 by gp78 and degraded. However, the C215 residue is oxidized by elevated reactive oxygen species (ROS) during C2C12 myoblasts differentiating into myotubes, preventing Insig-2 from ubiquitylation and degradation. The stabilized Insig-2 downregulates lipogenesis through inhibiting the SREBP pathway, helping to channel the carbon flux to ATP generation and protecting myotubes from lipid over-accumulation. Evolutionary analysis shows that the YECK (in which C represents Cys215 in human Insig-2) tetrapeptide sequence in Insig-2 is highly conserved in amniotes but not in aquatic amphibians and fishes, suggesting it may have been shaped by differential selection. Together, this study suggests that competitive oxidation-ubiquitylation on Cys215 of Insig-2 senses ROS and prevents muscle cells from lipid accumulation.

2.
Adv Mater ; 32(1): e1904815, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31746047

RESUMO

Helicity indicates the in-plane magnetic-moment swirling direction of a skyrmionic configuration. The ability to reverse the helicity of a skyrmionic bubble via purely electrical means has been predicted in frustrated magnetic systems; however, it has been challenging to observe this experimentally. The current-driven helicity reversal of the skyrmionic bubble in a nanostructured frustrated Fe3 Sn2 magnet is experimentally demonstrated. The critical current density required to trigger the helicity reversal is 109 -1010 A m-2 , with a corresponding pulse-width varying from 1 µs to 100 ns. Computational simulations reveal that both the pinning effect and dipole-dipole interaction play a crucial role in the helicity reversal process.

3.
J Biol Chem ; 295(1): 138-145, 2020 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-31757808

RESUMO

The functions of the glycine receptor (GlyR) and GABAA receptor (GABAAR) are both impaired in hyperekplexia, a neurological disorder usually caused by GlyR mutations. Although emerging evidence indicates that cannabinoids can directly restore normal GlyR function, whether they affect GABAAR in hyperekplexia remains unknown. Here we show that dehydroxylcannabidiol (DH-CBD), a synthetic nonpsychoactive cannabinoid, restores the GABA- and glycine-activated currents (IGABA and IGly , respectively) in HEK293 cells coexpressing a major GABAAR isoform (α1ß2γ2) and GlyRα1 carrying a human hyperekplexia-associated mutation (GlyRα1 R271Q). Using coimmunoprecipitation and FRET assays, we found that DH-CBD disrupts the protein interaction between GABAAR and GlyRα1 R271Q Furthermore, a point mutation of GlyRα1, changing Ser-296 to Ala-296, which is critical for cannabinoid binding on GlyR, significantly blocked DH-CBD-induced restoration of IGABA and IGly currents. This S296A substitution also considerably attenuated DH-CBD-induced disruption of the interaction between GlyRα1 R271Q and GABAAR. These findings suggest that, because it restores the functions of both GlyRα1 and GABAAR, DH-CBD may represent a potentially valuable candidate drug to manage hyperekplexia.

4.
Hum Brain Mapp ; 41(1): 95-106, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31532054

RESUMO

Studying cortical hemispheric asymmetries during the dynamic early postnatal stages in macaque monkeys (with close phylogenetic relationship to humans) would increase our limited understanding on the possible origins, developmental trajectories, and evolutional mechanisms of brain asymmetries in nonhuman primates, but remains a blind spot to the community. Via cortical surface-based morphometry, we comprehensively analyze hemispheric structural asymmetries in 134 longitudinal MRI scans from birth to 20 months of age from 32 healthy macaque monkeys. We reveal that most clusters of hemispheric asymmetries of cortical properties, such as surface area, cortical thickness, sulcal depth, and vertex positions, expand in the first 4 months of life, and evolve only moderately thereafter. Prominent hemispheric asymmetries are found at the inferior frontal gyrus, precentral gyrus, posterior temporal cortex, superior temporal gyrus (STG), superior temporal sulcus (STS), and cingulate cortex. Specifically, the left planum temporale and left STG consistently have larger area and thicker cortices than those on the right hemisphere, while the right STS, right cingulate cortex, and right anterior insula are consistently deeper than the left ones, partially consistent with the findings in human infants and adults. Our results thus provide a valuable reference in studying early brain development and evolution.

5.
Biophys Chem ; 256: 106282, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31756664

RESUMO

Structural investigations, based on density functional theory (DFT) calculations, are performed on tea catechins, including 4-aminobutyric acid (GABA), L-theanine (Thea), caffeine (CAF), theobromine (TB), theophylline (TP), catechin (C), epicatechin (EC), gallocatechin (GC), epigallocatechin (EGC), catechin gallate (CG), epicatechin gallate (ECG), gallocatechin gallate (GCG) and epigallocatechin gallate (EGCG). With an identified lowest energy conformer of investigated molecules, FTIR and FT-Raman spectra have been assigned according to DFT calculations in the way of B3LYP/6-31 + G (d, p). Normal spectra of these catechin powders are also measured by Raman spectrometers. There is a kind of everlasting correlation between experimental results and theoretical data. And our research has also obtained a clear evidence for reliable assignments of vibrational bands, bringing great feasibility to the rapid tea catechin detection.


Assuntos
Catequina/química , Espectroscopia de Infravermelho com Transformada de Fourier , Análise Espectral Raman , Chá/química , Catequina/análogos & derivados , Chá/metabolismo
6.
J Pediatr Orthop ; 2019 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-31834243

RESUMO

BACKGROUND: Pediatric lateral humeral condyle fractures (LHCFs) are sometimes misdiagnosed and inappropriately treated on the basis of x-ray radiographs because cartilage cannot be seen on radiographs. However, as a useful technique, transverse ultrasonography can accurately and readily determine the integrity of the cartilage hinge in pediatric LHCFs. The purpose of this study was to assess the reliability of the Jakob classification, the treatment plan, and the necessity for further examination of pediatric LHCFs with the use of x-ray with and without transverse ultrasound images. METHODS: Five pediatric orthopaedic surgeons with different levels of experience evaluated 62 cases on the basis of the use of x-ray alone and x-ray combined with transverse ultrasound images. These 2 types of evaluations were repeated after an interval of 4 to 6 weeks. At the time of each evaluation, all observers were asked to classify the fractures according to the Jakob classification, to formulate treatment plans, and to determine whether further examinations were required. RESULTS: After the training of transverse ultrasound image interpretation, the interobserver reliability of the Jakob classification significantly improved from fair (a kappa of 0.54) to moderate (a kappa of 0.71) with the addition of transverse ultrasound images. The treatment plan was changed from conservative treatment to surgical treatment in 7% of the ratings but from surgical treatment to conservative treatment in 15% of the ratings after reviewing the ultrasound images, and the difference was statistically significant (P=0.003). CONCLUSIONS: The use of the Jakob classification and a treatment plan for pediatric LHCFs can be optimized by the addition of transverse ultrasound images, especially after training for transverse ultrasound image interpretation. LEVEL OF EVIDENCE: Level III-diagnostic study.

8.
Comput Math Methods Med ; 2019: 8152713, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31827589

RESUMO

In intensive care unit (ICU), it is essential to predict the mortality of patients and mathematical models aid in improving the prognosis accuracy. Recently, recurrent neural network (RNN), especially long short-term memory (LSTM) network, showed advantages in sequential modeling and was promising for clinical prediction. However, ICU data are highly complex due to the diverse patterns of diseases; therefore, instead of single LSTM model, an ensemble algorithm of LSTM (eLSTM) is proposed, utilizing the superiority of the ensemble framework to handle the diversity of clinical data. The eLSTM algorithm was evaluated by the acknowledged database of ICU admissions Medical Information Mart for Intensive Care III (MIMIC-III). The investigation in total of 18415 cases shows that compared with clinical scoring systems SAPS II, SOFA, and APACHE II, random forests classification algorithm, and the single LSTM classifier, the eLSTM model achieved the superior performance with the largest value of area under the receiver operating characteristic curve (AUROC) of 0.8451 and the largest area under the precision-recall curve (AUPRC) of 0.4862. Furthermore, it offered an early prognosis of ICU patients. The results demonstrate that the eLSTM is capable of dynamically predicting the mortality of patients in complex clinical situations.

9.
J Intensive Care ; 7: 54, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31827802

RESUMO

Background: A spontaneous breathing trial (SBT) is a major diagnostic tool to predict successfully extubation in patients. Several factors may lead to weaning failure, including the degree of lung aeration loss and diaphragm dysfunction. The main objective was to compare the diaphragmatic contractility between patients with high lung aeration loss and low lung aeration loss during a 30-minute SBT by ultrasound. Methods: This was a prospective single-center study. Lung ultrasound aeration score (LUS) and diaphragmatic thickening fraction (DTF) were measured during mechanical ventilation 1 h before SBT (T-1), 30 min (T1), and 120 min (T2) after the start of the SBT during quiet breathing. The right and left DTF were compared between patients with LUS ≥ 14 (high lung aeration loss), considered at high risk of post-extubation distress, and those with LUS < 14 (low lung aeration loss). The relationship between the LUS and DTF and the changes in LUS and DTF from T-1 to T2 in patients with LUS ≥ 14 were assessed. Results: Forty-nine patients were analyzed; 33 had LUS ≥ 14 and 16 had LUS < 14 at T1. The DTF at T1 was significantly higher in patients with LUS ≥ 14 than in those with LUS < 14: the right median (IQR) DTF was 22.2% (17.1 to 30.9%) vs. 14.8% (10.2 to 27.0%) (p = 0.035), and the left median (IQR) DTF was 25.0% (18.4 to 35.0%) vs. 18.6% (9.7 to 24.2%) (p = 0.017), respectively. There was a moderate positive correlation between the LUS and the DTF (Rho = 0.3, p = 0.014). A significant increase in the LUS was observed from T-1 to T1, whereas no change was found between T1 and T2. The DTF remained stable from T-1 to T2. Conclusions: During a SBT, diaphragmatic contraction acts differently depending on the degree of pulmonary aeration. In patients with high lung aeration loss, increased diaphragmatic contractility indicates an additional respiratory effort to compensate lung volume loss that would contribute to successful SBT. Further studies are needed to evaluate the combined evaluation of lung aeration and diaphragmatic function to predict the successful weaning of patients from mechanical ventilation.

10.
Viruses ; 11(12)2019 Dec 13.
Artigo em Inglês | MEDLINE | ID: mdl-31847269

RESUMO

The QX-type avian infectious bronchitis virus (IBV) is still a prevalent genotype in Southwestern China. To analyze the antigenicity and pathogenicity characteristics of the dominant genotype strains (QX-type), S1 gene sequence analysis, virus cross-neutralization tests, and pathogenicity test of eight QX-type IBV isolates were conducted. Sequence analysis showed that the nucleotide homology between the eight strains was high, but distantly related to H120 and 4/91 vaccine strains. Cross-neutralization tests showed that all eight strains isolated from 2015 and 2017 belonged to the same serotype, but exhibited antigenic variations over time. The pathogenicity test of the five QX-type IBV isolates showed that only three strains, CK/CH/SC/DYW/16, CK/CH/SC/MS/17, and CK/CH/SC/GH/15, had a high mortality rate with strong respiratory and renal pathogenicity, whereas CK/CH/SC/PZ/17 and CK/CH/SC/DYYJ/17 caused only mild clinical symptoms and tissue lesions. Our results indicate that the prevalent QX-type IBVs displayed antigenic variations and pathogenicity difference. These findings may provide reference for research on the evolution of IBV and vaccine preparation of infectious bronchitis (IB).

11.
J Ethnopharmacol ; 251: 112522, 2019 Dec 25.
Artigo em Inglês | MEDLINE | ID: mdl-31883474

RESUMO

ETHNOPHARMACOLOGICAL RELEVANCE: Morning glory seed (MGS), has been widely used in treating constipation especially towards children. Clinically, people usually take fried MGS (MGSF) in formulas to reduce its side effect. However, the safety of MGSF other than MGS has yet to be explored. OBJECTIVE: The study aimed to reveal the potential mechanisms of using MGSF instead of MGS basing on chemistry, pharmacodynamics and toxicology. METHODS: The chemical compositions of the extracts of MGS and MGSF were compared using UPLC-Q-TOF/MS method. Simultaneously, to prove the availability and safety of MGSF, we investigated the laxative effect and subchronic toxicity of MGS and MGSF and addressed the mechanism of laxative effect of them. RESULTS: In this study, less phenolic acids and more fatty acids were detected in MGSF compared with the compounds in MGS. Moreover, we found that MGS group had stronger laxative effect than MGSF group via downregulating the expression of AQP3 protein. As for subchronic toxicity test, the body weights of MGS group were lower than MGSF group. In serum biochemistry and histopathological examinations, MGS group could cause more serious toxicity in liver, kidney and colon than MGSF group with higher values of BUN, Cr, AST and ALP. CONCLUSION: Based on the findings in this study, MGSF with varied compounds contents could still keep the laxative effect while retain less subchronic toxicity, which emphasized the necessity of processing and provided an insight into the rational use of MGSF in clinical practice.

12.
J Biosci Bioeng ; 2019 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-31672431

RESUMO

CotA-laccases are potential enzymes that are widely used in decolorization of dyes and degradation of toxic substances. In this study, a novel CotA-laccase gene from Bacillus pumilus W3 was applied for rational design. After a series of site-directed genetic mutations, the mutant S208G/F227A showed a 5.1-fold higher catalytic efficiency (kcat/Km) than the wild-type CotA-laccase did. The optimal pH of S208G/F227A was 3.5 with ABTS as substrate. The residual activity of mutant S208G/F227A was more than 80% after incubated for 10 h at pH 7-11. Mutant S208G/F227A showed optimal temperature at 80°C with ABTS as substrate. The thermal stability of mutant laccase S208G/F227A was lower than that of wild-type CotA-laccase. This study showed that Gly208 and Ala227 play key roles in catalytic efficiency and it is possible to improve catalytic efficiency of CotA-laccase through site-directed mutagenesis.

13.
J Ginseng Res ; 43(4): 618-624, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31695568

RESUMO

Background: Ginsenoside Re (Re) is one of the major components of Panax ginseng Meyer. Ginsenoside Rk3 (Rk3) is a secondary metabolite of Re. The aim of this study was to investigate and compare the effects and underlying mechanisms of Re and Rk3 on cyclophosphamide-induced myelosuppression. Methods: The mice myelosuppression model was established by intraperitoneal (i.p.) injection of cyclophosphamide. Peripheral blood cells, bone marrow nucleated cells, and colony yield of hematopoietic progenitor cells in vitro were counted. The levels of erythropoietin, thrombopoietin, and granulocyte macrophage colony-stimulating factor in plasma were measured by enzyme-linked immunosorbent assay. Bone marrow cell cycle was performed by flow cytometry. The expression of apoptotic protein bcl-2, bax, and caspase-3 was detected by Western blotting. Results: Both Re and Rk3 could improve peripheral blood cells, bone marrow nucleated cell counts, thymus index, and spleen index. Furthermore, they could enhance the yield of colonies cultured in vitro and make the levels of granulocyte macrophage colony-stimulating factor, erythropoietin, and thrombopoietin normal, reduce the ratio of G0/G1 phase cells, and increase the proliferation index. Finally, Re and Rk3 could upregulate the expression of bcl-2, whereas they could downregulate the expression of bax and caspase-3. Conclusion: Re and Rk3 could improve the hematopoietic function of myelosuppressed mice. The effect of Rk3 was superior to that of Re at any dose. Regulating the levels of cytokines, promoting cells enter the normal cell cycle, regulating the balance of bcl-2/bax, and inhibiting the expression of caspase-3 may be the effects of Re and Rk3 on myelosuppression.

14.
Int J Neurosci ; : 1-10, 2019 Dec 11.
Artigo em Inglês | MEDLINE | ID: mdl-31680595

RESUMO

Objective: Altered glutamatergic neurotransmission has been implicated in the pathogenesis of obsessive-compulsive disorder (OCD). We examined the effects and potential mechanism of glutamate-related drugs on compulsive behavior in quinpirole (QNP)-sensitized rats, to deepen our understanding of the link between OCD and glutamate.Method: This study systematically compared the effects of the partial NMDA agonist D-Cycloserine and the NMDA antagonist NVP-AAMO77, Ro25-6981 on compulsive behavior using the elevated zero maze, open field, and marble burying tests in QNP-induced OCD model.Results: The competitive N-methyl-D-aspartate glutamate receptor (NMDAR) antagonists NVP-AAMO77 (5 mg/kg) and Ro25-6981 (5 mg/kg) significantly inhibited anxiety-like and compulsive behavior in rats. And D-Cycloserine at all doses showed significant suppression on anxiety-like and marble-burying behavior. Glutamic acid (Glu) levels, reflecting changes in the glutamatergic neurotransmission, were significantly decreased in rat hippocampus of the NVP-AAMO77 and D-Cycloserine-treated group compared to the saline-treated group. The levels of other amino acids were unaffected. Moreover, NVP-AAMO77 significantly decreased the expression of the subunit NR2A of the NMDAR, and Ro25-6981 suppressed the level of the subunit NR2B of the NMDAR, while D-Cycloserine decreased both the subunit NR2A and NR2B of the NMDAR.Conclusion: Collectively, these findings suggest a functional role of NMDARs in anxiety and compulsive behaviors, with NMDARs inhibition promoting anxiolytic-like and anti-compulsive responses. These findings suggest that D-cycloserine, NVP-AAMO77, and Ro25-6981 could be useful drugs for the treatment of OCD, which may be due to the suppression of NR2A- or NR2B- containing NMDAR.

15.
Anal Chem ; 91(24): 15777-15783, 2019 Dec 17.
Artigo em Inglês | MEDLINE | ID: mdl-31718148

RESUMO

The power factories in cells, mitochondria, play important roles in all physiological processes. It is reported that progressive mitochondrial swelling and outer mitochondrial membrane rupture could be induced by a wide variety of apoptotic and necrotic stimuli. Regrettably, although a variety of mitochondrial probes have been developed, most of them are based on the detection of active species in mitochondria. Probes that can monitor the status and distribution of mitochondria for a long time are still urgently needed. In this study, a fluorescent sensor with excellent properties, EtNBEn, is described. Outstanding performance allows it to be observed not only in cells but also in living Daphnia and zebrafish under confocal microscopy for a long time. Moreover, the swelling process of mitochondria under light stimulation is also visualized under super-resolution (SR) microscopy. All these results suggest that EtNBEn could be employed for tagging mitochondria in various physiological processes, which makes a great contribution to the cure of diseases.

16.
Mol Biol Evol ; 2019 Nov 08.
Artigo em Inglês | MEDLINE | ID: mdl-31702777

RESUMO

Adaptations to different diets represent a hallmark of animal diversity. The diets of birds are highly variable, making them an excellent model system for studying adaptive evolution driven by dietary changes. To test whether molecular adaptations to diet have occurred during the evolution of birds, we examined a dietary enzyme alanine-glyoxylate aminotransferase (AGT), which tends to target mitochondria in carnivorous mammals, peroxisomes in herbivorous mammals, and both mitochondria and peroxisomes in omnivorous mammals. A total of 31 bird species were examined in this study, which included representatives of most major avian lineages. Of these, 29 have an intact mitochondrial targeting sequence (MTS) of AGT. This finding is in stark contrast to mammals, which showed a number of independent losses of the MTS. Our cell-based functional assays revealed that the efficiency of AGT mitochondrial targeting was greatly reduced in unrelated lineages of granivorous birds, yet it tended to be high in insectivorous and carnivorous lineages. Furthermore, we found that proportions of animal tissue in avian diets were positively correlated with mitochondrial targeting efficiencies that were experimentally determined, but not with those that were computationally predicted. Adaptive evolution of AGT mitochondrial targeting in birds was further supported by the detection of positive selection on MTS regions. Our study contributes to the understanding of how diet drives molecular adaptations in animals, and suggests that caution must be taken when computationally predicting protein subcellular targeting.

17.
J Phys Condens Matter ; 32(14): 143001, 2019 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-31689688

RESUMO

The field of magnetic skyrmions has been actively investigated across a wide range of topics during the last decades. In this topical review, we mainly review and discuss key results and findings in skyrmion research since the first experimental observation of magnetic skyrmions in 2009. We particularly focus on the theoretical, computational and experimental findings and advances that are directly relevant to the spintronic applications based on magnetic skyrmions, i.e. their writing, deleting, reading and processing driven by magnetic field, electric current and thermal energy. We then review several potential applications including information storage, logic computing gates and non-conventional devices such as neuromorphic computing devices. Finally, we discuss possible future research directions on magnetic skyrmions, which also cover rich topics on other topological textures such as antiskyrmions and bimerons in antiferromagnets and frustrated magnets.

18.
Biologicals ; 2019 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-31753578

RESUMO

The traditional vaccine strains, such as LaSota, do not completely prevent the shedding of NDV. An ideal vaccine which could not only prevent the clinical signs, but significantly reduce the shedding of NDV is urgently needed for the eradication of ND. In this study, an NDV isolate APMV-1/Chicken/China (SC)/PT3/2016 (hereafter referred as PT3) was identified as a class Ⅰ NDV and a lentogenic strain. The antigenic relationship between PT3 and 3 other NDV strains, including vaccine strain LaSota and 2 prevalent genotype Ⅶd and Ⅵb strains were analyzed. The protective efficacy of PT3 and LaSota against challenge with genotype Ⅶd and Ⅵb strains were assessed. The antigenic analysis result showed that 4 strains belong to the single serotype and the PT3 antiserum exhibited the highest HI titer against 3 other NDV strains. The results of protective efficacy showed that both of LaSota and PT3 could provide 100% survivability for infected chickens. However, PT3 performed better in inducing higher humoral responses and reducing virus shedding than the LaSota strain. Lentogenic strains from Class I NDV appear to be promising vaccine candidates for the control of ND, and allows for the easy discrimination of field NDV and vaccine strains.

19.
Plast Reconstr Surg ; 144(6): 1323-1333, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31764645

RESUMO

BACKGROUND: Mature adipocytes dedifferentiate in vivo on application of a soft-tissue expander. Dedifferentiated adipocytes can proliferate and redifferentiate. This study used tissue expanders to pretreat adipose flaps, to increase the retention rate after fat graft. METHODS: A soft-tissue expander and silicone sheet were implanted beneath the left and right inguinal fat pads of rats, respectively. After 7 days of expansion, the adipose tissue derived from the pads was transplanted beneath dorsal skin. Samples were harvested at various time points, and histologic, immunohistochemical, and gene expression analyses were conducted. Mature adipocytes were cultured in vitro under a pressure of 520 Pa. Changes in cell morphology, the cytoskeleton, and expression of mechanical signal-related proteins were investigated. RESULTS: Pressure in adipose flaps increased to 25 kPa on expansion. Mature adipocytes dedifferentiated following expansion. At 1 week after transplantation, the expression of vascular endothelial growth factor (p < 0.05) was higher in the expanded group. The retention rate at 12 weeks after transplantation was higher in the expanded group (56 ± 3 percent) than in the control group (32 ± 3 percent) (p < 0.05), and the surviving/regenerating zones (p < 0.01) were wider. The lipid content of mature adipocytes gradually decreased on culture under increased pressure, and these cells regained a proliferative capacity. This was accompanied by increased expression of mechanical signal--related proteins (p < 0.05). CONCLUSIONS: Mechanical signals may induce dedifferentiation of mature adipocytes. Dedifferentiated adipocytes increase the retention rate of fat grafts by acting as seed cells.

20.
Anal Bioanal Chem ; 411(27): 7187-7196, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31620825

RESUMO

Surface-enhanced Raman spectroscopy (SERS) has the potential to detect pesticide residues in agricultural products. However, some systemic pesticides, such as chlorpyrifos, can enter the plant tissue, and not just stay on the surface. Consequently, many SERS studies halted at practical application because of its complexity. In this work, SERS technology was used to detect chlorpyrifos residues in tea products at the semiquantitative level. A simple pretreatment method effectively avoided interference of other fluorescent substances, and all major peaks could be distinguished on the basis of a novel substrate. A principal component analysis algorithm was applied to form a regression model, and a nanogram detection limit was obtained. Furthermore, chlorpyrifos residues in the same tea products were also measured by gas chromatography-mass spectrometry, and the results show a small range of errors. From the comparative study of the two detection methods, the results suggest the great promise of SERS technology for rapid inspection of agricultural products.


Assuntos
Clorpirifos/análise , Resíduos de Praguicidas/análise , Análise Espectral Raman/métodos , Chá/química , Cromatografia Gasosa-Espectrometria de Massas , Limite de Detecção , Praguicidas/análise
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