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1.
Anal Chim Acta ; 1202: 339689, 2022 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-35341508

RESUMO

Molecularly imprinted polymer (MIP) membranes prepared in situ present several advantages: they maintain the original morphology, adhere strongly to the collector, and exhibit a controllable structure. In this study, a Ni-polyacrylamide (PAM)-MIP matrix was fabricated in situ on glassy carbon via the one-step electro-polymerization of AM monomers in the presence of Ni and template molecules. Ni2+ ions were introduced as oxidants to promote AM polymerization and bulking agents to fabricate a three-dimensional porous PAM-MIP matrix. The Ni-PAM-based MIP sensor exhibited a quantitative dual response toward dopamine (DA) and adenine (Ade) in the pH range of 5.0-9.0. The linear concentration range changed depending on the pH environment, and the concentrations of DA and Ade ranged from 0.6 to 200 µM and from 0.4 to 300 µM, respectively. The ranges of detection limits (S/N = 3) were 0.12-0.37 µM for DA and 0.15-0.36 µM for Ade. In addition, the dual-MIP sensor exhibited high reliability in the detection of DA and Ade in human serum owing to its excellent anti-interference ability and long-term stability. The technique developed in this study is expected to facilitate the construction of multi-target response electrochemical biosensors and the reliable determination of small molecules with high selectivity and stability.


Assuntos
Dopamina , Impressão Molecular , Resinas Acrílicas , Adenina , Dopamina/química , Técnicas Eletroquímicas/métodos , Humanos , Limite de Detecção , Impressão Molecular/métodos , Polímeros/química , Reprodutibilidade dos Testes
2.
Sci Rep ; 12(1): 2219, 2022 02 09.
Artigo em Inglês | MEDLINE | ID: mdl-35140317

RESUMO

Bladder cancer (BLCA) is the most common malignancy whose early diagnosis can ensure a better prognosis. However, the predictive accuracy of commonly used predictors, including patients' general condition, histological grade, and pathological stage, is insufficient to identify the patients who need invasive treatment. Autophagy is regarded as a vital factor in maintaining mitochondrial function and energy homeostasis in cancer cells. Whether autophagy-related genes (ARGs) can predict the prognosis of BLCA patients deserves to be investigated. Based on BLCA data retrieved from the Cancer Genome Atlas and ARGs list obtained from the Human Autophagy Database website, we identified prognosis-related differentially expressed ARGs (PDEARGs) through Wilcox text and constructed a PDEARGs-based prognostic model through multivariate Cox regression analysis. The predictive accuracy, independent forecasting capability, and the correlation between present model and clinical variables or tumor microenvironment were evaluated through R software. Enrichment analysis of PDEARGs was performed to explore the underlying mechanism, and a systematic prognostic signature with nomogram was constructed by integrating clinical variables and the aforementioned PDEARGs-based model. We found that the risk score generated by PDEARGs-based model could effectively reflect deteriorated clinical variables and tumor-promoting microenvironment. Additionally, several immune-related gene ontology terms were significantly enriched by PDEARGs, which might provide insights for present model and propose potential therapeutic targets for BLCA patients. Finally, a systematic prognostic signature with promoted clinical utility and predictive accuracy was constructed to assist clinician decision. PDEARGs are valuable prognostic predictors and potential therapeutic targets for BLCA patients.


Assuntos
Autofagia/genética , Neoplasias da Bexiga Urinária/diagnóstico , Neoplasias da Bexiga Urinária/genética , Biomarcadores Tumorais/genética , Correlação de Dados , Bases de Dados Genéticas , Feminino , Regulação Neoplásica da Expressão Gênica , Humanos , Estimativa de Kaplan-Meier , Masculino , Análise Multivariada , Nomogramas , Prognóstico , Fatores de Risco , Microambiente Tumoral/genética
3.
J Colloid Interface Sci ; 614: 532-537, 2022 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-35121511

RESUMO

Evidence shows that self-supported electrocatalysts are crucial role to solving environmental and energy issues. In this study, self-supported 2D metal-organic framework (MOF) nanosheets grown in situ on nickel-iron foam (NFF) were prepared by a one-step solvothermal process. The hierarchical nanostructure possesses a high specific surface area and abundant metal sites, which are beneficial for electrocatalytic reactions. In the electrocatalytic oxygen evolution reaction (OER), the optimal NiFe(20Ni)-MOF/NFF can drive current densities of 10, 50 and 100 mA cm-2 at small overpotentials of 226, 277 and 294 mV, respectively. According to the characterization results, the OER performance is improved by the synergistic action of bimetals and the generation of hydroxides/oxyhydroxides. This work provides new insights into fabricating self-supported MOF-based electrodes for water splitting that are simple and highly efficient.

4.
J Agric Food Chem ; 70(4): 1293-1303, 2022 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-35075900

RESUMO

Copper (Cu) is a common additive in food products, which poses a potential concern to animal and human health when it is in excess. Here, we investigated the relationship between endoplasmic reticulum (ER) stress and pyroptosis in Cu-induced toxicity of jejunum in vivo and in vitro. In in vivo experiments, excess intake of dietary Cu caused ER cavity expansion, elevated fluorescence signals of GRP78 and Caspase-1, and increased the mRNA and protein expression levels related to ER stress and pyroptosis in pig jejunal epithelium. Simultaneously, similar effects were observed in IPEC-J2 cells under excess Cu treatment. Importantly, 4-phenylbutyric acid (ER stress inhibitor) and MKC-3946 (IRE1α inhibitor) significantly inhibited the ER stress-triggered IRE1α-XBP1 pathway, which also alleviated the Cu-induced pyroptosis in IPEC-J2 cells. In general, these results suggested that ER stress participated in regulating Cu-induced pyroptosis in jejunal epithelial cells via the IRE1α-XBP1 pathway, which provided a novel view into the toxicology of Cu.


Assuntos
Estresse do Retículo Endoplasmático , Endorribonucleases , Animais , Cobre/toxicidade , Células Epiteliais , Jejuno , Piroptose , Suínos
5.
Org Lett ; 24(2): 592-596, 2022 01 21.
Artigo em Inglês | MEDLINE | ID: mdl-34981945

RESUMO

Ansafurantrienins A-H, bearing a unique 5/6/8 dihydrofuran-fused benzo[b]azocine chromophore, were isolated from Streptomyces flaveolus. Their structures, especially in the dihydrofuran unit, were unambiguously established by spectroscopic analyses, molecular modeling, and TDDFT/ECD calculations. The ansafurantrienins were proposed to be generated via intramolecular [3 + 2] oxidative cycloaddition, which was achieved by photocatalytic reaction with UV light and oxygen and found to have solvent-dependent stereoselectivity. Ansafurantrienins showed significant antiproliferative effects against pancreatic cancer cells. The results led to a structural revision of strecacansamycins.

6.
J Org Chem ; 87(2): 1056-1064, 2022 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-34964353

RESUMO

An electrochemical cross-dehydrogenative coupling of indoles with xanthenes has been established at room temperature. This coupling reaction could proceed in the absence of any catalyst or external oxidant, and generate the indole derivatives in moderate yields. Mechanistic experiments support that a radical pathway maybe involved in this reaction system.

7.
J Environ Manage ; 304: 114260, 2022 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-34915386

RESUMO

The polyvinylidene difluoride (PVDF) membrane has received considerable attention as a flexible surface enhanced Raman scattering (SERS) substrate due to its excellent mechanical and physicochemical properties. However, the poor fouling resistance of PVDF membrane due to its intrinsic hydrophobic property limits its practical application. To address this, in this investigation, a SERS imprinted membrane is synthesized based on W18O49/Ag composites. Firstly, to promote hydrophilicity, N-vinyl-2-pyrrolidone (NVP) and triethoxyvinylsilane (VTES) are copolymerized by hydrolysis condensation and linked with engineered polyvinypyrrolidone (PVP) chains exposed on the surface of membrane. Furthermore, W18O49/Ag composites are dispersed on the membrane under the assistance of polydopamine (pDA) to promote the pollution resistance. Subsequently, in order to demonstrate the practical detection property, W18O49/Ag/PVDF membrane is selected as the SERS substrate to synthesize SERS imprinted membrane by precipitation polymerization for the selective detection of L-tyrosine. The characteristic results reveal that the SERS-imprinted membrane exhibits satisfactory hydrophilicity, and it can effectively degrade the pollutant molecules absorbed on its surface under ultraviolet light illumination. It is proved from the detection results that the LOD of WADP-MIMs for L-tyrosine reached 10-9 mol L-1 when the concentration of L-tyrosine changed between 10-3-10-9 mol L-1. The correlation coefficient (R2) is 0.994 and the limit of detection is 10-9 mol L-1. Meanwhile, it can be applied for the selective detection of L-tyrosine in mixture samples. Overall, this study presents a novel approach for the hydrophilic modification and pollution resistance enhancement of PVDF-based SERS imprinted membrane, which can be effectively utilized for the selective detection of practical samples.


Assuntos
Polivinil , Tirosina , Polímeros de Fluorcarboneto , Interações Hidrofóbicas e Hidrofílicas , Análise Espectral Raman
8.
Anal Chim Acta ; 1190: 339264, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34857144

RESUMO

A surface acoustic wave (SAW) gas sensor with an Au/TiO2/poly(3,4-ethylenedioxythiophene) (PEDOT, which is a conductive polymer with photoelectric conversion function) sensing film was constructed for the quantitative detection of water vapor and CO2. The Au/TiO2/PEDOT sensing film was assembled on the delayed region of the 204 MHz SAW delay line, which was used as the base device for the gas sensor. The center frequency of the sensor decreases with an increase in relative humidity (RH), and the center frequency increases with increasing CO2 concentration, so that not only can the two gases be identified, but quantitative analysis can also be performed. The SAW sensor has a response range of 5%-90% for RH and a response range of 500-2000 ppm for CO2 gas. The shifts in center frequency varied linearly with the concentrations, giving rise to the sensitivities of -0.0068 and -0.1880 kHz %-1 for RH and ∼0.003 kHz ppm-1 CO2. The response/recovery time is 9 s/9.2 s for 700 ppm CO2 and 15 s/14 s for 70% RH. The experimental results show that the SAW sensor offers excellent selectivity, wide response range, rapid response, and good stability and repeatability. The mechanism of humidity and CO2 sensing is attributed to the hydrophilic porous structure of the Au/TiO2/PEDOT sensing film, and also to the reversible variation of its viscoelasticity under illumination conditions. The sensor, combined with the communication function of its own SAW device, has several prospective applications in the monitoring of atmospheric conditions.


Assuntos
Dióxido de Carbono , Som , Compostos Bicíclicos Heterocíclicos com Pontes , Umidade , Polímeros , Titânio
9.
Front Oncol ; 11: 771036, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34869004

RESUMO

BACKGROUND: Urothelial carcinoma of the bladder (UCB) is a common cancer of the urinary system. Despite substantial improvements in available treatment options, the survival outcome of patients with advanced UCB is unsatisfactory. Therefore, it is necessary to identify new prognostic biomarkers for monitoring and therapy guidance of UCB. In recent years, prostate-specific membrane antigen (PSMA) and CD248 have been identified promising candidate bio7markers. METHODS: In this study, we first examined PSMA and CD248 expression in tissues from 124 patients with UCB using immunohistochemical and immunofluorescent staining. We then analyzed the association between the expression of the two biomarkers and other clinicopathological features and prognosis. Finally, we performed bioinformatic analysis of CD248 and FOLH 1 (PSMA) using the TCGA-BLCA dataset to explore the underlying mechanism of PSMA and CD248 in the progression of UCB. RESULTS: Among the 124 cases, PSMA and CD248 were confirmed to be expressed in tumor-associated vessels. Vascular PSMA and CD248 expression levels were associated significantly with several deteriorated clinicopathological features. Furthermore, using univariate and multivariate Cox analyses, high vascular PSMA and CD248 expression levels were observed to be associated significantly with poor prognosis in patients with UCB. As risk factors, both PSMA and CD248 expression showed good performance to predict prognosis. Furthermore, combining these vascular molecules with other clinical risk factors generated a risk score that could promote predictive performance. Bioinformatic analysis showed that both PSMA and CD248 might contribute to angiogenesis and promote further progression of UCB. CONCLUSION: Both PSMA and CD248 are specifically expressed in the tumor-associated vasculature of UCB. These two molecules might be used as novel prognostic biomarkers and vascular therapeutic targets for UCB.

10.
Molecules ; 26(23)2021 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-34885958

RESUMO

Terpene synthases are widely distributed in Actinobacteria. Genome sequencing of Streptomyces sp. NRRL S-4 uncovered a biosynthetic gene cluster (BGC) that putatively synthesizes pentalenolactone type terpenes. Guided by genomic information, the S-4 strain was chemically investigated, resulting in the isolation of two new sesquiterpenoids, 1-deoxy-8α-hydroxypentalenic acid (1) and 1-deoxy-9ß-hydroxy-11-oxopentalenic acid (2), as shunt metabolites of the pentalenolactone (3) biosynthesis pathway. Their structures and absolute configurations were elucidated by analyses of HRESIMS and NMR spectroscopic data as well as time-dependent density functional theory/electronic circular dichroism (TDDFT/ECD) calculations. Compounds 1 and 2 exhibited moderate antimicrobial activities against Gram-positive and Gram-negative bacteria. These results confirmed that the pentalenolactone pathway was functional in this organism and will facilitate efforts for exploring Actinobacteria using further genome mining strategies.


Assuntos
Antibacterianos/química , Streptomyces/química , Antibacterianos/isolamento & purificação , Antibacterianos/metabolismo , Antibacterianos/farmacologia , Vias Biossintéticas , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Positivas/efeitos dos fármacos , Família Multigênica , Sesquiterpenos/química , Sesquiterpenos/isolamento & purificação , Sesquiterpenos/metabolismo , Sesquiterpenos/farmacologia , Streptomyces/genética , Streptomyces/metabolismo
11.
Front Oncol ; 11: 773063, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34970489

RESUMO

BACKGROUND: The tumor microenvironment (TME) plays an important role in the progression of renal cell carcinoma (RCC). Cancer-associated fibroblasts (CAFs) are considered to constitute a major component of the TME and participate in various tumor-promoting molecular events. We have previously confirmed that CD248 represents a promising biomarker of CAFs, which may provide insight into CAF-based tumor-promoting effects. However, CAF-mediated tumor progression and the potential mechanism of CD248 remain largely unknown in RCC patients. METHODS: Expression profiling and clinical data of RCC patients were obtained from The Cancer Genome Atlas (TCGA) database. An MCP-counter algorithm and Kaplan-Meier survival analysis were performed to explore the prognostic value of CAFs and CD248, respectively. A Pearson correlation coefficient test and Student's t-test were employed to evaluate the relationship between immunosuppressive TME and CD248 or CAFs. Immunohistochemistry and immunofluorescence staining were performed to confirm CD248 expression within CAFs. CD248-specific siRNA was used to investigate the potential function of CD248 in CAF tumor promotion. Differentially expressed genes (DEGs), weighted gene co-expression network analysis (WGCNA), and enrichment analysis were conducted to clarify the function of CD248+ CAFs in RCC progression and the associated regulatory mechanism. RESULTS: CD248 overexpression and CAF infiltration could predict poor RCC prognosis, which may involve the immunosuppressive TME. CD248 may serve as a promising CAFs biomarker and be involved with the tumor-promoting effect of CAFs. Moreover, CD248+ CAF infiltration may contribute to RCC progression and an immunosuppressive TME through cell-extracellular matrix (ECM) interactions and metabolism regulation. CONCLUSION: CD248+ CAFs participate in the regulation of RCC progression and immunosuppressive TME, which may represent a novel prognostic and therapeutic target for RCC.

12.
Nanoscale ; 13(42): 17953-17960, 2021 Nov 04.
Artigo em Inglês | MEDLINE | ID: mdl-34698752

RESUMO

Developing efficient and promising non-noble catalysts that can promote both the HER and OER in the same electrolyte is vital. Currently, these reported bifunctional catalysts show only moderate electrocatalytic water-splitting performance, which is much lower than expected. In addition, most of these promising nonprecious electrocatalysts work well only at small current densities (e.g. 10 mA cm-1), but at large current densities their stability and activity are far from satisfactory for practical applications. Herein, we have successfully constructed an urchin-like Ni3S2@Ni3B heterostructure electrocatalyst on Ni plates. The resulting material exhibits great catalytic activities for both the HER and OER, even at large current densities, reaching a current density of 1000 mA cm-l at relatively low applied overpotentials of 517 and 632 mV, respectively. The excellent catalytic performance of Ni3S2@Ni3B/NP is found to benefit from the effective integration of the unique surface structure and the interface electronic structure.

13.
Mater Sci Eng C Mater Biol Appl ; 127: 112237, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34225877

RESUMO

For developing electrochemical plant sensors, in-situ detection of hormone levels in living plants is worth attempting. A microneedle array sensor based on Au@SnO2-vertical graphene (VG)/Ta microelectrodes was constructed for analyzing abscisic acid (ABA) in plants. Graphene was vertically grown on Ta wires with a diameter of 0.6 mm by direct current arc plasma jet chemical vapor deposition with SnO2 as the Au catalyst carrier. These VG nanosheets were embedded with core-shell Au@SnO2 nanoparticles, and the formation mechanism of the sensing layer was investigated. Three Au@SnO2-VG microelectrodes, one Ti wire, and one Pt wire were packed into a microneedle array sensor with a three-electrode system. ABA was then quantitatively detected by direct electrocatalytic oxidation, which involves the synergistic catalytic effects of the abundant catalytic active sites of the Au@SnO2 nanoparticles and the excellent conductivity of the VG nanosheets. The microneedle array sensor responds to ABA in the pH range 4-7, the response concentration range was 0.012 (or 0.024)-495.2 µM, and the detection limit varied between 0.002 and 0.005 µM. The small size, wide pH range, low detection limit, and wide linear concentration range allow the microneedle array sensor to be inserted into plants for in-situ detection of ABA.


Assuntos
Grafite , Nanopartículas , Ácido Abscísico , Catálise , Técnicas Eletroquímicas
14.
Chem Commun (Camb) ; 57(57): 7047-7050, 2021 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-34179907

RESUMO

Herein, we report a mild dearomative [5+2]/[2+2] cycloaddition of 1H-indoles with ortho-(trimethylsilyl)aryl triflates. The unique [5+2] cycloaddition enables the synthesis of a series of dibenzo[b,e]azepine derivatives in moderate to good yields. Increasing the steric hindrance at the C2-position of 1H-indoles leads to the [2+2] cycloaddition. Mechanistic investigations support that the reaction of 1H-indoles with arynes undergoes a [2+2] cycloaddition step, followed by a ring expansion to the [5+2] cycloaddition product.

15.
Dalton Trans ; 50(26): 9076-9087, 2021 Jul 06.
Artigo em Inglês | MEDLINE | ID: mdl-34124728

RESUMO

Metastable Cu2O is an attractive material for the architectural design of integrated nanomaterials. In this context, Cu2O was used as the sacrificial agent to form the core-shell structure of Cu2O@HKUST-1 by in situ growth technology. The MOFs with BOPs adsorption property were gathered together by a Cu2O etching method, and the hollow structure of the HKUST-1 shell material with fast BOP adsorption was successfully constructed. The adsorption experiments showed that the HKUST-1 shell has a good adsorption effect on nitrobenzene pollutants in wastewater. The investigation of various factors affecting the adsorption, thermodynamic and kinetic equations was carried out. The adsorption equilibrium was reached within 30 min, and the maximum adsorption capacity was 94.67 mg g-1 at 298 K. The adsorption capacity of nitrobenzene by the HKUST-1 shell is in good agreement with the Freundlich model and the second-order kinetic model. The possible mechanism of adsorption of nitrobenzene by the HKUST-1 shell was discussed. The experimental results suggested that Cu-BTC materials have potential applications for wastewater treatment involving benzene pollutants.

16.
Biosens Bioelectron ; 187: 113326, 2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34004544

RESUMO

High-efficiency electroencephalogram (EEG) dry electrodes are a key component of brain-computer interface (BCI) technology because of their direct contact with the scalp. In this study, a semi-flexible polydopamine (PDA)/Pt-TiO2 electrode is prepared for the dry-contact acquisition of EEG signals. The PDA biofilm adheres strongly to the scalp and maintains a dynamic balance of water and ions. The Pt nanoparticles and TiO2 nanotube array together result in fast electron transfer. Therefore, the interface impedance between the dry PDA/Pt-TiO2 electrode and scalp is as low as 19.63-24.53 kΩ. The spontaneous EEG signal collected simultaneously using the dry PDA/Pt-TiO2 and wet Ag/AgCl electrodes had a correlation coefficient of up to 99.9%. In a steady-state visual evoked potential (SSVEP)-based BCI system, the dry electrode was used to collect EEG feedback signals for stimulations at 27 different frequencies in the range of 7-19.25 Hz. For these feedback signals, O1, Oz, and O2 channels in the occipital area exhibited high signal-to-noise ratios of 11.3, 11.8, and 11 dB, respectively. A volunteer wore an EEG headband with three PDA/Pt-TiO2 dry electrodes and successfully controlled the robotic arm of the SSVEP-BCI system in the untrained mode. The dry PDA/Pt-TiO2 electrode-based EEG cap is comfortable to wear, the identification signals of the SSVEP paradigm are accurate, and it is suitable for controlling external devices including a keyboard in the SSVEP-BCI system.


Assuntos
Técnicas Biossensoriais , Interfaces Cérebro-Computador , Eletrodos , Eletroencefalografia , Potenciais Evocados Visuais , Humanos
17.
Sci Total Environ ; 766: 144187, 2021 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-33418249

RESUMO

Although the chemical compositions and sources of organic aerosols (OAs) have been extensively investigated at the summit of Mt. Tai in the North China Plain (NCP), their vertical distributions and characterizations in the Mt. Tai region is not well known. To better understand the vertical variations of OAs in the urban and mountainous atmosphere, PM2.5 samples were collected simultaneously on a daytime/nighttime basis at two sites of different altitudes (Taian urban site: 20 m above ground; the summit of Mt. Tai: 1534 m a.s.l.) during the summer of 2016. The concentrations of all the determined chemical compounds (e.g., OC, EC, inorganic ions, saccharides, n-alkanes, PAHs and hopanes) except for biogenic secondary organic aerosol (BSOA) tracers decreased with the increase in sampling height, indicating the relatively larger contribution of anthropogenic pollutants to OAs at the lower heights. The relatively low concentration levels of biomass burning tracers (e.g., levoglucosan, galactosan and mannosan) and the insignificant correlations of levoglucosan with carbonaceous species demonstrated a negligible effect of biomass burning on the mountaintop atmosphere. The enhanced concentrations of BSOA tracers were observed with the increase of height, largely due to the more intensive secondary oxidation of volatile organic compounds (VOCs) under the stronger radiation conditions at the summit. The daytime concentrations of carbonaceous species, primary sugars, sugar alcohols, PAHs and low molecular weight n-alkanes were significantly higher than those in nighttime at Mt. Tai, suggesting that these chemical compounds at the summit of Mt.Tai aerosols were transported from the ground surface by valley breezes in daytime. There was no correlation between BSOA tracers and relative humidity (RH) or liquid water content (LWC) at both the sites, because both the high RH and LWC can suppress the acid-catalyzed formation of BSOA due to the dilution of the aerosol acidity.

18.
Anal Chim Acta ; 1145: 103-113, 2021 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-33453871

RESUMO

The in vivo detection of small active molecules in plant tissues is essential for the development of precision agriculture. Tryptophan (Trp) is an important precursor material for auxin biosynthesis in plants, and the detection of Trp levels in plants is critical for regulating the plant growth process. In this study, an electrochemical plant sensor was fabricated by electrochemically depositing a polydopamine (PDA)/reduced graphene oxide (RGO)-MnO2 nanocomposite onto a glassy carbon electrode (GCE). PDA/RGO-MnO2/GCE exhibited high electrocatalytic activity for the oxidation of Trp owing to the combined selectivity of PDA and catalytic activity of RGO-MnO2. To address the pH variability of plants, a reliable Trp detection program was proposed for selecting an appropriate quantitative detection model for the pH of the plant or plant tissue of interest. Therefore, a series of linear regression curves was constructed in the pH range of 4.0-7.0 using the PDA/RGO-MnO2/GCE-based sensor. In this pH range, the linear detection range of Trp was 1-300 µM, the sensitivity was 0.39-1.66 µA µM-1, and the detection limit was 0.22-0.39 µM. Moreover, the practical applicability of the PDA/RGO-MnO2/GCE-based sensor was successfully demonstrated by determining Trp in tomato fruit and juice. This sensor stably and reliably detected Trp levels in tomatoes in vitro and in vivo, demonstrating the feasibility of this research strategy for the development of electrochemical sensors for measurements in various plant tissues.


Assuntos
Grafite , Técnicas Eletroquímicas , Indóis , Compostos de Manganês , Óxidos , Polímeros , Triptofano
19.
Spine (Phila Pa 1976) ; 46(22): 1542-1550, 2021 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-32049938

RESUMO

STUDY DESIGN: A retrospective study. OBJECTIVE: Investigate the diagnosis and surgery strategy for treatment of development spinal canal stenosis (DSSA) at atlas plane based on computerized tography (CT) image characters. SUMMARY OF BACKGROUND DATA: The occurrence of spinal canal stenosis in the atlas plane is relatively rare compared with lower cervical. METHODS: Fifteen patients diagnosed with DSSA were included from 2014 to 2018. They are divided into four subgroups based on the character of CT images: group I (small size atlas), group II (hypertrophy of posterior arch of the atlas [PAA]), group III (incurved of PAA), and group IV (hypertrophy odontoid). RESULTS: There are type I 7, type II 3, type III 2, and group IV 3 in the 15 cases. All the patients received different surgery procedures respectively: (1) posterior arch osteotomy were performed for group I/III//IV without atlantoaxial dislocation, (2) posterior arch resect and replantation were performed for group II, (3) occipital cervical fixation and fusion were added to the patients with associated atlantoaxial dislocation (AAD), (4) a new method of odontoid reduce and atlantoaxial fixation by transoral approach were performed for group IV with associated AAD. All cases underwent surgery successfully which included posterior occipitocervical fixation (OCF) + posterior arch resection (PAR) eight cases, PAR four cases, posterior arch remodeling and re-implantation (PARR) two cases, and Dens remodeling + trans-oral anterior reduction and plate fixation (DR+TARP) one case without severe complications. All patients show different improvement in the symptoms. Japanese orthopaedic association score improved from 9.2 to 14.7 in 1 year follow-up. CONCLUSION: DSSA could be easily diagnosed and divided into four subgroups according to the character of CT image, corresponding surgery strategy could receive a fine clinical result.Level of Evidence: 4.


Assuntos
Articulação Atlantoaxial , Atlas Cervical , Luxações Articulares , Fusão Vertebral , Atlas Cervical/diagnóstico por imagem , Atlas Cervical/cirurgia , Constrição Patológica , Humanos , Estudos Retrospectivos , Canal Medular , Resultado do Tratamento
20.
Sci Total Environ ; 758: 143709, 2021 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-33223177

RESUMO

To eliminate the spread of a novel coronavirus breaking out in the end of 2019 (COVID-19), the Chinese government has implemented a nationwide lockdown policy after the Chinese lunar New Year of 2020, resulting in a sharp reduction in air pollutant emissions. To investigate the impact of the lockdown on aerosol chemistry, the number fraction, size distribution and formation process of oxalic acid (C2) containing particles and its precursors were studied using a single particle aerosol mass spectrometer (SPAMS) at the urban site of Liaocheng in the North China Plain (NCP). Our results showed that five air pollutants (i.e., PM2.5, PM10, SO2, NO2, and CO) decreased by 30.0-59.8% during the lockdown compared to those before the lockdown, while O3 increased by 63.9% during the lockdown mainly due to the inefficient titration effect of O3 via NO reduction. The increased O3 concentration can boost the atmospheric oxidizing capacity and further enhance the formation of secondary organic aerosols, thereby significantly enhancing the C2 particles and its precursors as observed during the lockdown. Before the lockdown, C2 particles were significantly originated from biomass burning emissions and their subsequent aqueous-phase oxidation. The hourly variation patterns and correlation analysis before the lockdown suggested that relative humidity (RH) and aerosol liquid water content (ALWC) played a key role in the formation of C2 particles and the increased aerosol acidity can promote the conversion of precursors such as glyoxal (Gly) and methyglyoxal (mGly) into C2 particles in the aqueous phase. RH and ALWC decreased sharply but O3 concentration and solar radiation increased remarkably during the lockdown, the O3-dominated photochemical pathways played an important role in the formation of C2 particles in which aerosol acidity was ineffective. Our study indicated that air pollution treatment sponges on a joint-control and balanced strategy for controlling numerous pollutants.


Assuntos
Poluentes Atmosféricos , COVID-19 , Aerossóis/análise , Poluentes Atmosféricos/análise , China , Controle de Doenças Transmissíveis , Monitoramento Ambiental , Humanos , Material Particulado/análise , Processos Fotoquímicos , SARS-CoV-2
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