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Aiming at the problems that the traditional image recognition technology is challenging to extract useful features and the recognition time is extended; the AlexNet model is improved to improve the effect of image classification and recognition. This study focuses on 8 types of tomato leaf diseases and healthy leaves. By using HOG and LBP weighted fusion to extract image features, a tomato leaf disease recognition model based on the AlexNet model is proposed, and transfer learning is used to train the AlexNet model. Transfer the knowledge learned by the AlexNet model on the PlantVillage image dataset to this model while reducing the number of fully connected layers. Keras deep learning framework and programming language Python were used. The model was implemented, and the classification and identification of tomato leaf diseases were carried out. The recognition rate of feature-weighted fusion classification is higher than that of serial and parallel methods, and the recognition time is the shortest. When the weight coefficient ratio of HOG and LBP is 3:7, the image recognition rate is the highest, and its value is 97.2 %. From the model performance curve See, when the number of iterations is more than 150 times, the training set and test accuracy rate both exceed 97 %, the loss rate shows a gradient decline, and the change is relatively stable; compared with the traditional AlexNet model, HOG + LBP + SVM model, and VGG model, improved AlexNet model has the highest recognition rate, and it has high recall value, accuracy, and F1 value; Compared with the latest convolutional neural network disease recognition models, improved AlexNet model recognition accuracy was 98.83 %, and the F1 value was 0.994. It shows that the model has good convergence performance, fast prediction speed, and low loss rate and can effectively identify 8 types of tomato leaf images, which provides a reference for the research on crop disease identification.
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Alite-ye'elimite-belite-ferrite cement (AYBFC) integrates the advantages of calcium sulfoaluminate cement and Portland cement, but its ultra-early strength needs to be further improved when applied to rush repair and construction works. In this study, the ultra-early strength of AYBFC was improved using lithium carbonate (Li2CO3) and superplasticizer. The results showed that an appropriate amount of Li2CO3 could significantly improve the ultra-early strength of AYBFC, since it was capable of promoting the hydration reaction of AYBFC. After polycarboxylate superplasticizer was doped on this basis, the ultra-early compressive strength of AYBFC was further improved. This was because the superplasticizer could markedly enhance the matrix compactness despite its inhibitory effect on the hydration reaction of cement and the generation of hydration products.
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We have developed a widely applicable (radio)fluoro-iodination of alkenes using readily available and easily handled KF (18F). The reactions exhibited high functional group tolerance and needed only an ambient atmosphere. Furthermore, the resulting product could be further functionalized with various nucleophiles.
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Glass fibers are widely used in cement-based precast products, given the reinforcing requirements for toughness and strength. However, inferior alkali resistance hinders the effectiveness of glass fibers in reinforcing cement-based materials. In this paper, nanoparticle coatings were applied on the surface of alkali-resistant glass fiber (ARGF) as a protective layer via the in situ chemical reaction of oleic acid (OA) and potassium permanganate (PP). The morphology and constituents of the as-prepared ARGFs were examined using scanning electron microscopy (SEM) and obtaining X-ray photoelectron spectroscopy (XPS) measurements. Mass loss and strength retention were investigated to characterize alkali resistance of modified ARGFs. Results showed that ARGFs could be optimally coated by a layer of MnO2-based nanoparticles consisting of approximately 70% MnO2, 18% MnO, and 12% MnSiO3, when modified with an optimum OA to PP ratio of 10 for 24 h. The dissolution of ARGFs matrix in 4% and 10% NaOH solutions were distinctly delayed to 28 d, as a consequence of the introduction of the MnO2-based nanoparticle layer, compared with nontreated ARGF occurring at 3 d in 4% NaOH solution. For the optimally modified ARGFs, the mass loss was controlled to 1.76% and 2.91% after 90 d of corrosion in 4% and 10% NaOH solutions, and the retention of tensile strength was increased by approximately 25%. With respect to the increment in alkali-resistant performance, the modified ARGFs can be promising candidates for wide applications in alkaline cement-based products.
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Crowd sequential annotations can be an efficient and cost-effective way to build large datasets for sequence labeling. Different from tagging independent instances, for crowd sequential annotations, the quality of label sequence relies on the expertise level of annotators in capturing internal dependencies for each token in the sequence. In this article, we propose modeling sequential annotation for sequence labeling with crowds (SA-SLC). First, a conditional probabilistic model is developed to jointly model sequential data and annotators' expertise, in which categorical distribution is introduced to estimate the reliability of each annotator in capturing local and nonlocal label dependencies for sequential annotation. To accelerate the marginalization of the proposed model, a valid label sequence inference (VLSE) method is proposed to derive the valid ground-truth label sequences from crowd sequential annotations. VLSE derives possible ground-truth labels from the tokenwise level and further prunes subpaths in the forward inference for label sequence decoding. VLSE reduces the number of candidate label sequences and improves the quality of possible ground-truth label sequences. The experimental results on several sequence labeling tasks of Natural Language Processing show the effectiveness of the proposed model.
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CONTEXT: Patients with spinal cord injury (SCI) are at high risk for venous thromboembolism (VTE). The risk factors for VTE in patients with SCI are complex. OBJECTIVE: This meta-analysis was conducted to clarify the risk factors for VTE in patients with SCI. METHODS: The Cochrane Library, PubMed, EBSCO, Web of Science, China National Knowledge Infrastructure (CNKI), China Biomedical Literature Database (CBM), Wanfang Med Data Database, and VIP Database were searched to identify studies reporting on risk factors for VTE in patients with SCI. RESULTS: The meta-analysis included 25 studies. Findings showed that risk of VTE in patients with SCI was significantly associated with middle- and old-age (OR = 2.08, 95%CI, 1.47, 2.95), male sex (OR = 1.41, 95%CI, 1.26, 1.59), complete paralysis (OR = 3.69, 95%CI, 2.60, 5.24), personal/family history of venous thrombosis (OR = 1.95, 95%CI, 1.35, 2.81), history of smoking (OR = 2.67, 95%CI, 1.79, 3.98), lack of compression therapy (OR = 2.44, 95%CI, 1.59, 3.73), presence of lower limb/pelvic fracture (OR = 3.47, 95%CI, 1.79, 6.75), paraplegia (OR = 1.81, 95%CI, 1.49, 2.19), and diabetes (OR = 4.24, 95%CI, 2.75, 6.52). CONCLUSION: The meta-analysis identified 9 risk factors for VTE in patients with SCI. Healthcare providers should be aware of the risk factors for VTE when rehabilitating patients with SCI.
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Fraturas Ósseas , Traumatismos da Medula Espinal , Tromboembolia Venosa , Trombose Venosa , Humanos , Masculino , Tromboembolia Venosa/epidemiologia , Tromboembolia Venosa/etiologia , Traumatismos da Medula Espinal/complicações , Traumatismos da Medula Espinal/epidemiologia , Incidência , Trombose Venosa/etiologia , Fatores de RiscoRESUMO
ABSTRACT Introduction: Strength training uses loads greater than 75% of 1RM of the individual, being indicated for optimization of endurance and controlled muscular hypertrophy. It is believed that the performance of badminton players can be improved with this technique, due to the intrinsic benefits regarding the power of muscle contraction explosion. Objective: Verify the influences of strength training on the physical fitness of badminton players. Methods: 24 young volunteer badminton players were randomly selected and divided into experimental and control groups. The experimental group was trained with high-load training, and the experimental data was recorded with FirstBeat® before and after the experiment. Results: The action speed of the experimental group was reduced from 216.46km/h to 240.81km/h, while the release speed was increased from 293.79km/h to 364.25km/h. The release velocity was significantly improved, increasing the net velocity from 169.57km/h to 200.94km/h, while the control group showed no statistical change. Conclusion: Strength training was found to significantly improve the physical fitness of badminton players, significantly impacting the finishing abilities of badminton players. Level of evidence II; Therapeutic studies - investigation of treatment outcomes.
RESUMO Introdução: O treinamento de força utiliza cargas maiores que 75% de 1RM do indivíduo, sendo indicadas para otimização de endurance e hipertrofia muscular controlada. Acredita-se que o desempenho dos jogadores de badminton possa ser aprimorado com essa técnica, devido aos benefícios intrínsecos quanto ao poder de explosão da contração muscular. Objetivo: Verificar as influências do treinamento de força sobre a aptidão física dos jogadores de badminton. Métodos: 24 jovens jogadores de badminton voluntários foram aleatoriamente selecionados e divididos em grupo experimental e grupo de controle. O grupo experimental foi treinado com treinamento de alta carga, sendo os dados experimentais registrados com FirstBeat® antes e depois do experimento. Resultados: A velocidade de ação do grupo experimental foi reduzida de 216,46km/h para 240,81km/h, enquanto a velocidade de liberação foi aumentada de 293,79km/h para 364,25km/h. A velocidade de liberação foi significativamente aprimorada, aumentando a velocidade líquida de 169,57km/h para 200,94km/h, enquanto o grupo de controle não apresentou alterações estatísticas. Conclusão: Constatou-se que o treinamento de força melhorou significativamente a aptidão física dos jogadores de badminton, impactando significativamente nas habilidades de finalização dos jogadores de badminton. Nível de evidência II; Estudos terapêuticos - investigação dos resultados do tratamento.
RESUMEN Introducción: El entrenamiento de fuerza utiliza cargas superiores al 75% de 1RM del individuo, siendo indicado para optimización de la resistencia e hipertrofia muscular controlada. Se cree que el rendimiento de los jugadores de bádminton puede ser mejorado con esta técnica, debido a los beneficios intrínsecos en cuanto al poder de explosión de la contracción muscular. Objetivo: Verificar las influencias del entrenamiento de fuerza en la condición física de jugadores de bádminton. Métodos: 24 jóvenes jugadores voluntarios de bádminton fueron seleccionados aleatoriamente y divididos en grupo experimental y grupo control. El grupo experimental fue entrenado con entrenamiento de alta carga, y los datos experimentales fueron registrados con FirstBeat® antes y después del experimento. Resultados: La velocidad de acción del grupo experimental se redujo de 216,46km/h a 240,81km/h, mientras que la velocidad de liberación aumentó de 293,79km/h a 364,25km/h. La velocidad de liberación mejoró significativamente, aumentando la velocidad neta de 169,57km/h a 200,94km/h, mientras que el grupo de control no mostró cambios estadísticos. Conclusión: Se constató que el entrenamiento de fuerza mejoró significativamente la aptitud física de los jugadores de bádminton, impactando significativamente en las habilidades de remate de los jugadores de bádminton. Nivel de evidencia II; Estudios terapéuticos - investigación de los resultados del tratamiento.
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The purinergic P2X7 receptor (P2X7R), an ATP gated ion channel, is an important therapeutic target for various inflammatory immune and neurodegenerative diseases. A novel P2X7R targeting radiotracer GSK1482160 was radiosynthesized by hetero-aryl bromides precursor 10 with [18F]Et4NF, 20-30 % radiochemical yield, > 68 GBq/µmol specific activity, >98 % radiochemical purity. Evaluation in healthy male Sprague-Dawley rats revealed that [18F]GSK1482160 ([18F]11) was stably retained 87.81 %, 72.45 %, and 56.32 % in brain, blood and liver respectively 60-min post-injection. Ex-vivo biodistribution of [18F]11 proved that it was able to target the P2X7R in vivo and there was no defluorination in the major organs. PET/MRI imaging and autoradiography revealed that [18F]11 was able to penetrate the blood-brain barrier (BBB) and to be a promising P2X7R PET radioligand for clinical translation.
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Brometos , Receptores Purinérgicos P2X7 , Trifosfato de Adenosina , Animais , Encéfalo/diagnóstico por imagem , Radioisótopos de Flúor , Masculino , Tomografia por Emissão de Pósitrons/métodos , Ácido Pirrolidonocarboxílico , Compostos Radiofarmacêuticos , Ratos , Ratos Sprague-Dawley , Distribuição TecidualRESUMO
Electrochemical oxygen evolution reaction (OER) always plays an important role in many electrochemical energy storage and conversion systems. Owing to the slow kinetics mainly brought from multiple proton-coupled electron transfer steps, the design and exploit low-cost, highly active, durable OER electrocatalysts are of significant importance. Although the black phosphorus (BP) shows good electrocatalytic OER performance, it still faces the problems of poor intrinsic activity and low stability due to its instability under ambient conditions. The NiFe-LDH was assembled onto the surfaces of exfoliated BP (EBP) nanoflakes to realize the interfacial coupling between them, achieving an effective improvement in electrocatalytic activity and stability. Benefitting from the interfacial P-O bonding, the NiFe-LDH@EBP hybrid shows high OER activity with a low overpotential of â¼240 mV@10 mA cm-2 toward OER under alkaline conditions, as well as the good stability. Density functional theory (DFT) calculations proved that the interface-coupling of NiFe-LDH on BP promotes charge transfer kinetics and balances the adsorption/desorption of reaction intermediates, ultimately imparting excellent OER electrocatalytic activity.
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Existing partial sequence labeling models mainly focus on a max-margin framework that fails to provide an uncertainty estimation of the prediction. Furthermore, the unique ground-truth disambiguation strategy employed by these models may include wrong label information for parameter learning. In this article, we propose structured Gaussian processes for partial sequence labeling (SGPPSL), which encodes uncertainty in the prediction and does not need extra effort for model selection and hyperparameter learning. The model employs factor-as-piece approximation that divides the linear-chain graph structure into the set of pieces, which preserves the basic Markov random field structure and effectively avoids handling a large number of candidate output sequences generated by partially annotated data. Then, confidence measure is introduced in the model to address different contributions of candidate labels, which enables the ground-truth label information to be utilized in parameter learning. Based on the derived lower bound of the variational lower bound of the proposed model, variational parameters and confidence measures are estimated in the framework of alternating optimization. Moreover, a weighted Viterbi algorithm is proposed to incorporate confidence measures to sequence prediction, which considers label ambiguity arose from multiple annotations in the training data and thus helps improve the performance. SGPPSL is evaluated on several sequence labeling tasks and the experimental results show the effectiveness of the proposed model.
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Objective: To investigate the effects of recombinant human epidermal growth factor eye drops combined with phacoemulsification on short- and long-term visual acuity recovery and related dry eye complications in patients with senile cataract. Methods: Sixty patients with senile cataract cured from January 2019 to January 2021 were enrolled in our hospital. The patients in the control group were arbitrarily assigned into the control and the research group. The former group received phacoemulsification, and the latter group received recombinant human epidermal growth factor (RhEGF) eye drops combined with phacoemulsification. The curative effect, the incidence of xerophthalmia, short-term and long-term vision improvement, changes of corneal endothelial cells, serum factors, and life quality scores were compared. Results: The effective rate of the research group was 90.00%, and the effective rate of the control group was 66.67%; the curative effect of the research group was higher than that of the control group (P < 0.05). The incidence of dry eye in the research group was lower than that in the control group (P < 0.05). The short-term and long-term visual acuity improvement effect of the research group was better than that of the control group (P < 0.05). After treatment, the density of corneal endothelial cells in the research group was higher than that in the control group, while the proportion of hexagonal cells and the coefficient of variation of corneal endothelial cells in the research group were lower than those in the control group (P < 0.05). After treatment, IL-6 and TNF-α in the research group were lower than those in the control group (P < 0.05). Compared with the control group, the physical function, psychological function, social function, and healthy self-cognition scores of the research group were all lower (P < 0.05). Conclusion: Cataract is the leading cause of blindness in the world. With the continuous improvement of cataract phacoemulsification technology, the incidence of some serious complications has gradually lessened. Xerophthalmia is one of the most obvious and predictable complications after cataract surgery and may affect the recovery of postoperative visual acuity. Recombinant human epidermal growth factor eye drops can effectively enhance the visual acuity of patients, promote the curative effect, and strengthen the life quality.
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Catarata , Família de Proteínas EGF , Facoemulsificação , Acuidade Visual , Xeroftalmia , Catarata/complicações , Família de Proteínas EGF/uso terapêutico , Células Endoteliais , Humanos , Soluções Oftálmicas , Xeroftalmia/etiologia , Xeroftalmia/terapiaRESUMO
The alkaline components in red mud represent one of the crucial factors restricting its application, especially for the construction and building industry. The phase state of alkaline components has a significant influence on the dealkalization of red mud. In this work, an environmentally friendly acid leaching strategy is proposed by controlling the phase transformation of red mud during active roasting pretreatment. With a moderate roasting temperature, the alkaline component is prevented from converting into insoluble phases. After acid leaching with a low concentration of 0.1 M, a high dealkalization rate of 92.8% is obtained. Besides, the leachate is neutral (pH = 7) and the valuable metals in red mud are well preserved, manifesting a high selectivity and efficiency of diluted acid leaching. The calcination experiment further confirms the practicability of the strategy in the construction field, where the cementitious minerals can be formed in large quantities. Compared with the traditional acid leaching routes, the diluted acid leaching strategy in this work is acid saving with low valuable element consumption. Meanwhile, the secondary pollution issue can be alleviated. Hence, the findings in this work provide a feasible approach for the separation and recovery of alkali and resource utilization of red mud.
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Existing disambiguation strategies for partial structured output learning just cannot generalize well to solve the problem that there are some candidates that can be false positive or similar to the ground-truth label. In this article, we propose a novel weak disambiguation for partial structured output learning (WD-PSL). First, a piecewise large margin formulation is generalized to partial structured output learning, which effectively avoids handling a large number of candidate-structured outputs for complex structures. Second, in the proposed weak disambiguation strategy, each candidate label is assigned with a confidence value indicating how likely it is the true label, which aims to reduce the negative effects of wrong ground-truth label assignment in the learning process. Then, two large margins are formulated to combine two types of constraints which are the disambiguation between candidates and noncandidates, and the weak disambiguation for candidates. In the framework of alternating optimization, a new 2n -slack variables cutting plane algorithm is developed to accelerate each iteration of optimization. The experimental results on several sequence labeling tasks of natural language processing show the effectiveness of the proposed model.
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Aprendizagem , Processamento de Linguagem Natural , AlgoritmosRESUMO
OBJECTIVE: There is no review or meta-analysis to compare the efficacy and safety of methotrexate plus anti-vascular endothelial growth factor (anti-VEGF) therapy in patients with diabetic macular edema (DME). It is worthy to critically review the evidence of the assessment of combined therapies to inform clinical practice. Therefore, the purpose of this study was to compare the efficacy and safety of methotrexate plus anti-VEGF therapy in the treatment of DME and to provide evidence for clinical practice. METHODS: The electronic databases of EMBASE, PubMed, Cochrane Library, and Web of Science were searched from the inception to April 2021 using the following key terms: "diabetic macular edema," "methotrexate," and "anti-vascular endothelial growth factor," for all relevant studies. Additionally, the reference lists from published original articles and relevant reviews were assessed to identify more relevant studies. Only English publications were included. Data were extracted by review of each study for population, mean age, gender, follow-up duration, study design, publishing date, characteristics, and outcomes assessment. The present study was performed using Review Manager (RevMan Version 5.3, The Cochrane Collaboration, Copenhagen, Denmark). RESULTS: We hypothesized that combined therapies would provide better therapeutic benefits compared to single method. OSF REGISTRATION NUMBER: 10.17605/OSF.IO/APD6 V.
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Inibidores da Angiogênese/uso terapêutico , Antirreumáticos/uso terapêutico , Retinopatia Diabética/tratamento farmacológico , Edema Macular/tratamento farmacológico , Metotrexato/uso terapêutico , Receptores de Fatores de Crescimento do Endotélio Vascular/antagonistas & inibidores , Quimioterapia Combinada , Humanos , Injeções Intravítreas , Edema Macular/etiologia , Metanálise como AssuntoRESUMO
A Bi(OTf)3 -catalyed reaction of 3-aryl propargyl alcohols with sulfonamide and halogen source was firstly investigated, which provided a facile route for the synthesis of a large variety of α-halo-ß-amino ketones. The key intermediates, ß-amino ketones, were obtained through tandem Meyer-Schuster rearrangement reaction of propargyl alcohols and intermolecular Michael addition of α, ß-unsaturated ketones and sulfonamide. Then the inâ situ generated α-halo-ß-amino ketones underwent the base-promoted intramolecular cyclization to give diverse acyl aziridines in a one-pot fashion. These transformations are reliable on a large scale. The high yields and convenient experimental operations make it a valuable method for the construction of α-halo-ß-amino ketones and acyl aziridine derivatives.
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With unique 2D nanostructures and excellent properties, graphene and its derivatives are a class of advanced nanosized reinforcements for cementitious materials. Sulfonated graphene (SG), one of the most important modified graphene materials, possesses sulfonate groups on the surface and significantly improves the mechanical and thermal properties of cement-based composites. It is important to investigate the influence of SG on cement-based materials as it is a prerequisite for practical applications. Herein, SG was prepared and introduced into cement paste to investigate its influence on the rheological properties of cement paste. With the increased addition of SG, a stable slurry was gradually obtained with low fluidity and high rheological parameters. The mechanism of the SG effect on the rheological properties of cement paste was also illustrated. Because of the high specific surface area and sulfonate groups of SG nanosheets, a large amount of flocculated structure was created by the complexing effect, chemical interaction, physical interaction and mechanical interlocking between SG and hydrated/unhydrated cement particles. Furthermore, polycarboxylate ether (PCE) superplasticizer was introduced to ensure fluidity and transportability in the practical application of SG. The results in this work lay a foundation for the practical application of modified graphene in cementitious materials.
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Calcium sulphoaluminate cement (CSA) has the characteristics of quick hardening, high early strength and high impermeability, however its strength growth persistence in the middle and late stages (after the age of 3 days) is poor. In order to improve this disadvantage, the pilot production of alite (C3S) modified CSA (AMCSA) clinker was carried out by liquid phase manipulation and barium ion doping technology. The effects of different dosages of gypsum on the hydration and hardening properties of AMCSA, such as setting time, hydration rate, compressive strength and hydration products, were studied. The results show that the mineral content of ye'elimite, C2S, C3S and iron phase in the calcined AMCSA clinker are 48.5 wt.%, 32.6 wt.%, 11.7 wt.% and 7.2 wt.% respectively, which are close to the designed mineral composition. The stable coexistence of ye'elimite and C3S in the same clinker system is realized. The initial and final setting time of AMCSA are retarded with the increasing gypsum dosage. When the gypsum dosage is 15 wt.% under the experimental conditions in this study, the AMCSA mortar reaches the highest compressive strength at every age. The strength of AMCSA mortar at 28 days is still significantly improved compared with that at 3 days, which indicates that the shortcoming of the low strength growth persistence of CSA in the middle and late stages is improved.
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STUDY DESIGN: Psychometrics study. OBJECTIVE: The objective of this study was to introduce a novel tool for pinprick sensation examination and validate its usefulness in patients with spinal cord injury (SCI). SETTING: China Rehabilitation Research Center, Capital Medical University School of Rehabilitation Medicine, China. METHODS: A set of cone tools with different tapers (22.5°, 45°, 67.5°, 90°, 112.5°, 135°, 157.5°, and 180°) was made. The cone tool was validated first in 91 able-bodied individuals and then in 30 patients with SCI. The reliability and validity of the cone tool were analyzed by comparing the results of a pinprick sensation examination with the results of the International Standards for the Neurological Classification of SCI (ISNCSCI), the cone tool, and the thermal analyzer. RESULTS: The intraclass correlation coefficient (ICC) of the cone tool in able-bodied individuals was between 0.48 and 0.94 while that of the cone tool and the ISNCSCI tool ranged between 0.43 and 0.78. Pinprick sensation in patients with SCI can be graded into five levels using four tapers (22.5°, 45°, 67.5°, and 90°): normal, slight impairment, moderate impairment, severe impairment, and complete loss of sensation. CONCLUSION: This easy-to-use cone tool can produce a reliable semi-quantitative pinprick test result and is useful for pinprick sensation examination in patients with SCI.
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Exame Neurológico/instrumentação , Exame Neurológico/normas , Sensação/fisiologia , Distúrbios Somatossensoriais/diagnóstico , Distúrbios Somatossensoriais/epidemiologia , Traumatismos da Medula Espinal/diagnóstico , Traumatismos da Medula Espinal/epidemiologia , Adolescente , Adulto , Idoso , Criança , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Exame Neurológico/métodos , Reprodutibilidade dos Testes , Adulto JovemRESUMO
A method has been developed for the determination of glyphosate (GLY), glufosinate (GLUF), and the main metabolite aminomethylphosphonic acid (AMPA) residues in dry tea based on ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) coupled with pre-column derivatization. A systematic study of the effects of pretreatment methods including extraction and purification procedures was designed and carried out for the determination of GLY, GLUF, and AMPA. The results indicated that the optimal pretreatment method was as follows:the tea sample was first extracted by water in vortex, and then purified by a cation exchange solid-phase extraction column with the elution of 0.5% (v/v) formic acid aqueous solution. Finally, the eluant was derivatized by 9-fluorenylmethyl chloroformate, and the target compounds were separated on a C18 chromatographic column and analysed by UPLC-MS/MS (ESI+). GLY, GLUF, and AMPA showed good linearity in the range of 1-100 µ g/L, with correlation coefficients above 0.991. The limits of detection and limits of quantification were found to be 0.0160-0.0300 mg/kg and 0.0530-0.100 mg/kg, respectively. The average spiked recoveries of GLY, GLUF, and AMPA varied from 78.3% to 108% at three spiked levels (0.0500, 0.400, and 1.20 mg/kg), while the relative standard deviations ranged from 5.46% to 9.63%. The proposed method was utilized to detect 837 batches of tea samples. The detection ratios of GLY, GLUF, and AMPA were 3.46%, 0.24%, and 4.42%, respectively, while 0.24% of the investigated tea samples had values above maximum residue limits. The developed method is simple, rapid, sensitive, and accurate for the determination of GLY, GLUF, and AMPA in dry tea and may be used for routine analysis.
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Aminobutiratos/análise , Glicina/análogos & derivados , Isoxazóis/análise , Chá/química , Tetrazóis/análise , Cromatografia Líquida de Alta Pressão , Fluorenos , Glicina/análise , Extração em Fase Sólida , Espectrometria de Massas em Tandem , GlifosatoRESUMO
OBJECTIVE: To establish sequence characterized amplified region markers of Cornus officinalis and provide a scientific basis for molecular identification of C. officinalis. METHOD: The random primer was screened through RAPD to obtain specific RAPD marker bands. The RAPD marker bands were separated, extracted, cloned and sequenced. Both ends of the sequence of RAPD marker bands were determined. A pair of specific primers was designed for conventional PCR reaction, and SCAR marker was acquired. RESULT: Four pairs of primers were designed based on the sequence of RAPD marker bands. The DNA of the seven varieties of C. officinalis was amplified by using YST38 and YST43 primer. The results showed that seven varieties of C. officinalis were able to produce a single PCR product. It was an effective way to identify C. officinalis. The varieties with cylindrical and long-pear shape fruits amplified by YST38 showed a specific band, which could be used as the evidence of variety identification. Seven varieties of C. oficinalis were amplified by using primer YST39. But the size of band of the variety with spindly shape fruit (35,0400 bp) was about 300 bp, which was shorter than those of the variety with the other shape fruits of C. officinalis (650-700 bp). The variety with the spindly shape fruit could be identified through this difference. The primer YST92 could produce a fragment from 600-700 bp in the varieties with cylindrical and long-pear shape fruits, a fragment from 200-300 bp in the varieties with oval and short-cylindrical shape fruits and had no fragment in the varieties with long cylindrical, elliptic and short-pear shape fruits, which could be used to select the different shapes of C. officinalis. CONCLUSION: SCAR mark is established and can be used as the basis for breeding and distinguishing the verieties of C. officinalis.