Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 18 de 18
Filtrar
Más filtros










Base de datos
Intervalo de año de publicación
1.
Sci Rep ; 14(1): 12603, 2024 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-38824256

RESUMEN

The RIME optimization algorithm (RIME) represents an advanced optimization technique. However, it suffers from issues such as slow convergence speed and susceptibility to falling into local optima. In response to these shortcomings, we propose a multi-strategy enhanced version known as the multi-strategy improved RIME optimization algorithm (MIRIME). Firstly, the Tent chaotic map is utilized to initialize the population, laying the groundwork for global optimization. Secondly, we introduce an adaptive update strategy based on leadership and the dynamic centroid, facilitating the swarm's exploitation in a more favorable direction. To address the problem of population scarcity in later iterations, the lens imaging opposition-based learning control strategy is introduced to enhance population diversity and ensure convergence accuracy. The proposed centroid boundary control strategy not only limits the search boundaries of individuals but also effectively enhances the algorithm's search focus and efficiency. Finally, to demonstrate the performance of MIRIME, we employ CEC 2017 and CEC 2022 test suites to compare it with 11 popular algorithms across different dimensions, verifying its effectiveness. Additionally, to assess the method's practical feasibility, we apply MIRIME to solve the three-dimensional path planning problem for unmanned surface vehicles. Experimental results indicate that MIRIME outperforms other competing algorithms in terms of solution quality and stability, highlighting its superior application potential.

2.
Materials (Basel) ; 16(17)2023 Aug 22.
Artículo en Inglés | MEDLINE | ID: mdl-37687430

RESUMEN

In this study, thermogravimetric measurements of nylon-6/polyethylene double-layer pouch wastes were conducted in N2 under a constant heating-rate mode, and the multiple heating-rate results were analyzed in terms of degradation features and specific temperatures. Experimental results show that the waste pyrolysis involves one reaction stage, and all specific parameters appear to increase with the heating rate. Kinetic analysis of non-isothermal data was thoroughly performed using various isoconversional model-free methods for the calculations of the activation energy, resulting in 143~215 kJ/mol over the whole pyrolysis process. By means of the model-fitting method, the reaction mechanism model g(α) and pre-exponential factor lnk0 are concurrently determined with the aid of the linear compensation effect. With such methodology proposed, the Avrami-Erofeev kinetic model A3/2 of g(α) = [-ln(1 - α)]2/3 is found to be the most appropriate mechanism function for describing the pyrolysis of the nylon-6/polyethylene waste along with lnk0 of 23.14 to 34.26 min-1. With the Arrhenius parameters thus obtained, the predictions were made and performed very satisfactorily to correlate experimental results. Additionally, the service life and thermodynamic parameters over the entire pyrolysis process were also estimated.

3.
Sensors (Basel) ; 23(6)2023 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-36991841

RESUMEN

The fault diagnosis of rolling bearings is critical for the reliability assurance of mechanical systems. The operating speeds of the rolling bearings in industrial applications are usually time-varying, and the monitoring data available are difficult to cover all the speeds. Though deep learning techniques have been well developed, the generalization capacity under different working speeds is still challenging. In this paper, a sound and vibration fusion method, named the fusion multiscale convolutional neural network (F-MSCNN), was developed with strong adaptation performance under speed-varying conditions. The F-MSCNN works directly on raw sound and vibration signals. A fusion layer and a multiscale convolutional layer were added at the beginning of the model. With comprehensive information, such as the input, multiscale features are learned for subsequent classification. An experiment on the rolling bearing test bed was carried out, and six datasets under various working speeds were constructed. The results show that the proposed F-MSCNN can achieve high accuracy with stable performance when the speeds of the testing set are the same as or different from the training set. A comparison with other methods on the same datasets also proves the superiority of F-MSCNN in speed generalization. The diagnosis accuracy improves by sound and vibration fusion and multiscale feature learning.

4.
Materials (Basel) ; 16(6)2023 Mar 14.
Artículo en Inglés | MEDLINE | ID: mdl-36984208

RESUMEN

Thermal decomposition of tennis ball rubber (TBR) wastes in nitrogen and air has been studied through thermogravimetric analysis. The samples were thermally decomposed from room temperature to 950 K at heating rates of 3 to 20 K/min with a purging flow of 30 cm3/min. The degradation features and specific temperatures for two purging gases are thus compared according to the nonisothermal results. Kinetic analyses of two thermal decomposition processes have been isoconversionally performed using differential or integral methods. The activation energy as a function of mass conversion has been thus obtained over the entire decomposition range, varying from 116.7 to 723.3 kJ/mol for pyrolysis and 98.2 to 383.6 kJ/mol for oxidative thermal decomposition. The iterative Flynn-Wall-Ozawa method combined with the linear compensation effect relationship has been proposed for determining the pre-exponential factor and reaction mechanism function, resulting in chemical order reaction models of f(α) = (1 - α)5.7 and f(α) = (1 - α)5.8 for describing pyrolysis and the oxidative thermal degradation of TBR wastes, respectively. With these kinetic parameters, very satisfactory matching against experimental data has been obtained for both gases. Additionally, the thermodynamic parameters, such as the changes of entropy, enthalpy and Gibbs free energy, over the whole thermal degradation processes have also been evaluated.

5.
Angew Chem Int Ed Engl ; 61(33): e202208577, 2022 Aug 15.
Artículo en Inglés | MEDLINE | ID: mdl-35751405

RESUMEN

Capturing radioactive iodomethane and its vapors is a major challenge due to its low adsorption capacity. Herein, we have developed for the first time a pyridine-entrapped elastic crosslinked polysulfate gel (pyridine/TPC-cPS) as an efficient absorbent for iodomethane capture. Each pyridine-encased TPC-cPS network cell acts as a mini-reactor for salt formation between pyridine and iodomethane. The yield reaches up to 96.65 % and traps saturated iodomethane vapor of 1.573 g gpyridine/TPC-cPS -1 (equivalent to 18.103 g gTPC-cPS -1 ), which is the highest capacity reported to date. Both experiments and molecular dynamics simulations reveal that the unusual adsorption of polysulfate for polar aprotic organics can be attributed to the fact that the electrostatic interactions between the polar group (O=S=O) in the polymer backbone and the polar groups in the organic molecules fixed the solvent in the polymer matrix, while the van der Waals forces between the nonpolar groups in the polymer and molecules induced swelling.

6.
Polymers (Basel) ; 14(8)2022 Apr 07.
Artículo en Inglés | MEDLINE | ID: mdl-35458253

RESUMEN

A detailed kinetic analysis of pyrolysis processes of Tennis string polyurethane (TSPU) waste and waterborne polyurethane (WPU) waste was carried out in the present paper. Non-isothermal pyrolysis characterizations of two wastes were acquired through thermogravimetric determinations under the constant heating rates of 5, 10, 15 and 20 K/min. Experimental results showed that the pyrolysis processes of TSPU and WPU were mainly characteristic of three stages and two stages, respectively. Two pyrolysis performance indices, the devolatilization index (DI) and heat-resistance index (HRI), were used to interpret the heating rate effect on the pyrolysis features and different thermal dependences of TSPU and WPU. Isoconversional kinetic analysis was thoroughly performed with model-free and model-fitting methods. By using Starink, Vyazovkin-Dollimore and Coats-Redfern methods, the activation energies thus obtained were in the range of 103.3~148.3 kJ/mol and 92.5~204.3 kJ/mol, respectively, for TSPU and WPU, over the entire pyrolysis process. Their respective pre-exponential factor lnA values were determined to be within 17.94~33.42 min-1 and 16.56~20.82 min-1. Thermodynamic parameters in terms of ΔG#, ΔH# and ΔS# throughout the entire pyrolysis process were also calculated. Finally, by means of the model-fitting Coats-Redfern method, the most appropriate mechanism functions were ascertained for, respectively, describing multi-stage pyrolysis degradations of TSPU and WPU waste. These results may offer meaningful support for designing any industrial pyrolysis reactor to dispose of polyurethane wastes.

7.
Phys Chem Chem Phys ; 24(16): 9176-9187, 2022 Apr 20.
Artículo en Inglés | MEDLINE | ID: mdl-35383346

RESUMEN

Bacterial DNA phosphorothioation (PT) physiologically and stereo-specifically replaces a non-bridging oxygen in a phosphate link with a sulfur atom, which can be recognized by a highly conserved sulfur-binding domain (SBD). Here we conducted thermodynamic integration (TI), molecular dynamics simulation, and quantum chemical calculations to decipher the specific molecular interactions between PT-DNA and SBD in Streptomyces coelicolor type IV restriction enzyme ScoMcrA. The TI-calculated binding affinity of (5'-CCGRp-PSGCCGG-3')2 is larger than that of (5'-CCGGCCGG-3')2 by about 7.4-7.7 kcal mol-1. The binding difference dominantly stems from hydration energy of non-phosphorothioate DNA (9.8-10.6 kcal mol-1) in aqueous solution, despite the persistent preference of 2.6-3.2 kcal mol-1 in the DNA-SBD MD simulations. Furthermore, the quantum chemical calculations reveal an unusual non-covalent interaction in the phosphorothioate-binding scenario, where the PS⋯NP165 chalcogen bond prevails the PS⋯HCß vdW interactions from the adjacent residues H116-R117-Y164-P165-A168. Thus, the chalcogen-hydrophobic interaction pulls PT-DNA into the SBD binding pocket while the water cage pulls a normal DNA molecule out. The synergetic mechanism suggests the special roles of the proline pyrrolidine group in the SBD proteins, consistent with the experimental observations in the X-ray crystallography and structural bioinformatics analysis.


Asunto(s)
Azufre , Agua , ADN/química , ADN Bacteriano , Interacciones Hidrofóbicas e Hidrofílicas , Fosfatos/química , Azufre/química
8.
ACS Appl Mater Interfaces ; 14(12): 14293-14301, 2022 Mar 30.
Artículo en Inglés | MEDLINE | ID: mdl-35290023

RESUMEN

Glycerol is a byproduct of biodiesel production and can be a low-cost source for some high-value C1-C3 chemicals. The conversion can be achieved by photo-, thermo-, and electro-catalysis methods. The electrocatalytic oxidation method is attractive due to its moderate reaction conditions and high electron to product efficiency. Most reported catalysts are based on noble metals, while metal oxides are rarely reported. Here, we investigated the electro-oxidation of glycerol on a series of ZnFexCo2-xO4 (x = 0, 0.4, 1.0, 1.4, and 2.0) spinel oxides. Seven types of value-added C1-C3 products including formate, glycolate, lactate, and glycerate can be obtained by this approach. The selectivity and Faraday efficiency toward these products can be tuned by adjusting the Fe/Co ratio and other experimental parameters, such as the applied potential, glycerol concentration, and electrolyte pH.

9.
Chemosphere ; 287(Pt 3): 132291, 2022 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-34562702

RESUMEN

A silk fibroin silicon-based composite aerogel (SSA) has been modified via a SuFEx reaction for application in the adsorption of anionic pollutants and antimicrobials in water. The tyrosine fragment in the silk fibroin was modified by a high yielding SuFEx click reaction. A quaternary ammonium salt functionality was introduced into the silk fibroin protein and the modified silk fibroin protein was crosslinked with tetraethyl orthosilicate. The aerogel was then prepared by freeze-drying. The aerogel obtained has biocompatibility and biodegradability properties. Four types of dyes (Methyl orange, Rhodamine B, Methylene blue and Acid red) were applied as targets and the saturated adsorption amounts were calculated. The adsorption behavior of the dyes towards SSA was studied by fitting Langmuir and Freundlich adsorption models. A pseudo-first order kinetic model and a pseudo-second order kinetic model were used to study the kinetics of the adsorption process. After 6 cycles, the removal rate of methyl orange by SSA remained at 81.25%. The adsorption capacity and anti-interference ability of SSA on some other polluting anions such as PO43- and CrO42- were also measured and the efficiency adsorption reached up to 70.94% and 77.91%, respectively. The antibacterial effect of SSA was evaluated with Escherichia coli and Staphylococcus aureus as representative examples.


Asunto(s)
Fibroínas , Adsorción , Antibacterianos , Azul de Metileno , Silicio
10.
Materials (Basel) ; 14(24)2021 Dec 09.
Artículo en Inglés | MEDLINE | ID: mdl-34947157

RESUMEN

Thermal degradation of nylon-6 tennis string nylon wastes in inert nitrogen and air atmospheres was investigated by means of multiple heating-rate thermogravimetric analyses. The results obtained under the heating rates of 5-20 K/min are compared in terms of degradation feature and specific temperature for two atmospheres. Using nonisothermal data, kinetic analysis was thoroughly conducted using various isoconversional model-free methods, including Starink, Madhusudanan-Krishnan-Ninan, Tang, Coats-Redfern, and Flynn-Wall-Ozawa methods. With these kinetic analysis methods, the activation energy over the entire degradation process was successfully calculated. By means of the model-fitting master-plots method, the first-order chemical reaction model was determined to be the most appropriate mechanism function for describing pyrolysis and oxidative thermal degradation of nylon-6 waste. Using kinetic parameters, satisfactory matching against experimental data resulted using the Coats-Redfern method for both cases. Furthermore, thermodynamic parameters such as changes in entropy, enthalpy, and Gibbs free energy during thermal degradation processes were evaluated.

11.
Chem Asian J ; 16(20): 3202-3208, 2021 Oct 18.
Artículo en Inglés | MEDLINE | ID: mdl-34402597

RESUMEN

Two small molecular monomers, ph-TPE and ph-TPE-CN, and their homopolymers Poly (ph-TPE) and Poly (ph-TPE-CN) containing tetra phenylethylene and sulfate structures, were synthesized by a sulfur (VI) fluorine exchange click reaction (SuFEx) and radical polymerization. All the monomers and polymers exhibit a typical aggregation-induced emission (AIE) effect both in the solid state and aggregated state. Moreover, based on the intermolecular charge transfer (ICT) effect between the tetra phenylethylene chromophore and p-nitrophenol, both polymers could be used for the selective detection of p-nitrophenol. The detection limit and reactivity coefficient of Poly (ph-TPE) are 0.081 µM and 5.15×104  M-1 , respectively, whereas the detection limit and reactivity coefficient of Poly (ph-TPE-CN) are 0.077 µM and 1.81×104  M-1 , respectively. This can be attributed to the greater sensitivity of Poly (ph-TPE-CN) to p-nitrophenol than that of Poly (ph-TPE). This work provides a new methodology for the preparation and broadening application of side-chain type AIE-active polysulfate fluorescent probes.

12.
J Hazard Mater ; 403: 123656, 2021 02 05.
Artículo en Inglés | MEDLINE | ID: mdl-33264865

RESUMEN

Ions, including anions and heavy metals, are extremely toxic and easily accumulate in the human body, threatening the health of humans and even causing human death at low concentrations. It is therefore necessary to detect these toxic ions in low concentrations in water. Fluorescent sensing is a good method for detecting these ions, but some conventional dyes often exhibit an aggregation caused quench (ACQ) effect in their solid state, limiting their large-scale application. Fluorescent probes based on aggregation-induced emission (AIE) properties have received significant attention due to their high fluorescence quantum yields in their nano aggragated states, easy fabrication, use of moderate conditions, and selevtive recognization of organic/inorganic compounds in water with obvious changes in fluorescence. We surmarize the recent advances of AIE-based sensors for low concentration toxic ion detection in water. The detection probes can be divided into three categories: chemical reaction types, chemical interaction types and physical interaction types. Chemical reaction types utilize nucleophilic addition and coordination reaction, while chemical interaction types rely on hydrogen bonding and anion-π interactions. The physical interaction types are composed of electrostatic attractions. We finally comment on the challenges and outlook of AIE-active sensors.

13.
Environ Sci Pollut Res Int ; 25(29): 29705-29714, 2018 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-30145752

RESUMEN

The plant root cell wall (CW) is the first structure that comes into contact with extracellular cadmium (Cd), and it plays an important role in the absorption, immobilization, and translocation of Cd in the roots. However, the differences in the cell wall components between Cd-tolerant and Cd-sensitive cultivars are unclear. A hydroponic experiment was carried out to investigate the differences in the concentrations of Cd, total sugars, and uronic acid in pectin, hemicellulose 1, hemicellulose 2, cellulose, and lignin, as well as pectin methylesterase enzyme activity (PME) in the roots of two soybean cultivars that differ with respect to Cd tolerance exposed to 0 and 23 µM Cd treatments. The bound forms of Cd in the roots were found to differ between the two soybean genotypes; 50.2% of the Cd in the root cell wall accumulates in the pectin in the highly Cd-tolerant and low Cd-accumulating cultivar HX3, while 50.6% of the root cell wall Cd accumulates in cellulose in the Cd-sensitive and high Cd-accumulating cultivar BX10. The total sugar and uronic acid concentrations of the cell wall components increased in response to Cd stress, while the concentrations of total sugars and uronic acid in BX10 were higher than in HX3 (except for hemicellulose 1). Increased demethylation of pectin may be the main reason that Cd is mainly concentrated in the primary wall in HX3, because the PME activity was higher in HX3 than it was in BX10 under Cd treatment. Furthermore, BX10 had a higher lignin concentration after Cd treatment, and showed the same change in cellulose. Cd in the root cell wall of BX10 was fixed in the secondary cell wall, which may be a result of the coupling to cellulose and lignin. In conclusion, root cell walls in soybean cultivars that differ in Cd tolerance may possess different mechanisms to prevent Cd from entering cells, and the sequestration of Cd in different cell wall components may determine the differences in Cd tolerance between the two genotypes.


Asunto(s)
Cadmio/toxicidad , Pared Celular/ultraestructura , Glycine max/efectos de los fármacos , Raíces de Plantas/efectos de los fármacos , Plantones/efectos de los fármacos , Contaminantes del Suelo/toxicidad , Transporte Biológico , Cadmio/metabolismo , Pared Celular/metabolismo , Hidroponía , Raíces de Plantas/metabolismo , Raíces de Plantas/ultraestructura , Plantones/metabolismo , Plantones/ultraestructura , Contaminantes del Suelo/metabolismo , Glycine max/metabolismo , Glycine max/ultraestructura
14.
Gigascience ; 6(6): 1-5, 2017 06 01.
Artículo en Inglés | MEDLINE | ID: mdl-28475810

RESUMEN

Rhodiola crenulata, a well-known medicinal Tibetan herb, is mainly grown in high-altitude regions of the Tibet, Yunnan, and Sichuan provinces in China. In the past few years, increasing numbers of studies have been published on the potential pharmacological activities of R. crenulata, strengthening our understanding into its putitive active ingredient composition, pharmacological activity, and mechanism of action. These findings also provide strong evidence supporting the important medicinal and economical value of R. crenulata. Consequently, some Rhodiola species are becoming endangered because of overexploitation and environmental destruction. However, little is known about the genetic and genomic information of any Rhodiola species. Here we report the first draft assembly ofthe R. crenulata genome, which was 344.5 Mb (25.7 Mb Ns), accounting for 82% of the estimated genome size, with a scaffold N50 length of 144.7 kb and a contig N50 length of 25.4 kb. The R. crenulata genome is not only highly heterozygous but also highly repetitive, with ratios of 1.12% and 66.15%, respectively, based on the k-mer analysis. Furthermore, 226.6 Mb of transposable elements were detected, of which 77.03% were long terminal repeats. In total, 31 517 protein-coding genes were identified, capturing 86.72% of expected plant genes in BUSCO. Additionally, 79.73% of protein-coding genes were functionally annotated. R. crenulata is an important medicinal plant and also a potentially interesting model species for studying the adaptability of Rhodiola species to extreme environments. The genomic sequences of R. crenulata will be useful for understanding the evolutionary mechanism of the stress resistance gene and the biosynthesis pathways of the different medicinal ingredients, for example, salidroside in R. crenulata.


Asunto(s)
Genoma de Planta , Rhodiola/genética , Análisis de Secuencia de ADN/métodos , Elementos Transponibles de ADN , Tamaño del Genoma , Medicina Tradicional Tibetana , Anotación de Secuencia Molecular
15.
Sci Rep ; 6: 24266, 2016 Apr 11.
Artículo en Inglés | MEDLINE | ID: mdl-27063002

RESUMEN

Anthropogenic sound has increased significantly in the past decade. However, only a few studies to date have investigated its effects on marine bivalves, with little known about the underlying physiological and molecular mechanisms. In the present study, the effects of different types, frequencies, and intensities of anthropogenic sounds on the digging behavior of razor clams (Sinonovacula constricta) were investigated. The results showed that variations in sound intensity induced deeper digging. Furthermore, anthropogenic sound exposure led to an alteration in the O:N ratios and the expression of ten metabolism-related genes from the glycolysis, fatty acid biosynthesis, tryptophan metabolism, and Tricarboxylic Acid Cycle (TCA cycle) pathways. Expression of all genes under investigation was induced upon exposure to anthropogenic sound at ~80 dB re 1 µPa and repressed at ~100 dB re 1 µPa sound. In addition, the activity of Ca(2+)/Mg(2+)-ATPase in the feet tissues, which is directly related to muscular contraction and subsequently to digging behavior, was also found to be affected by anthropogenic sound intensity. The findings suggest that sound may be perceived by bivalves as changes in the water particle motion and lead to the subsequent reactions detected in razor clams.


Asunto(s)
Conducta Animal/efectos de la radiación , Bivalvos/fisiología , ATPasa de Ca(2+) y Mg(2+)/metabolismo , Sonido , Animales , ATPasa de Ca(2+) y Mg(2+)/genética , Ciclo del Ácido Cítrico/genética , Ciclo del Ácido Cítrico/efectos de la radiación , Ácidos Grasos/biosíntesis , Expresión Génica/efectos de la radiación , Glucólisis/efectos de los fármacos , Glucólisis/genética , Modelos Biológicos , Nitrógeno/química , Nitrógeno/metabolismo , Oxígeno/química , Oxígeno/metabolismo , Agua de Mar/análisis , Triptófano/metabolismo
16.
Environ Sci Pollut Res Int ; 23(2): 1860-72, 2016 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-26403248

RESUMEN

To examine the differences in root morphological responses of soybean cultivars with different cadmium (Cd) tolerance and accumulation to Cd stress, the biomass, Cd concentration, and root morphological features of five soybean cultivars were determined under 0, 9, 23, 45, and 90 µM Cd stress via hydroponic experiments. Significantly genotypic differences in Cd tolerance and Cd concentration were observed between five soybean cultivars at four Cd levels. For Cd tolerance, HX3 showed a strong Cd tolerance with tolerance indexes of shoot biomass at 92.49, 76.44, 60.21, and 46.45% after 18 days at four Cd levels, and others had similar weak tolerance at young seedling. For Cd accumulation, Cd concentration in roots showed far higher than that in shoots. The different accumulation features in roots and shoots among five cultivars were found at four Cd levels. Comparing with the control, the total root length (RL), root surface area (SA), and root volume (RV) of all cultivars were decreased significantly at four Cd levels. Tolerant cultivar HX3 had the largest root system and sensitive cultivar BX10 had the smallest root system at young seedling stage. Correlation analysis indicated that RL, SA, and RV were positively correlated with root biomass and shoot biomass under 9 and 23 µM Cd treatments, but root average diameter (RD) was negatively correlated with shoot biomass and root biomass only under 9 µM Cd treatments, while RL and SA were negatively correlated with root Cd concentration under 23 and 45 µM Cd treatments. The results suggested that root morphological traits were closely related to Cd tolerance at young seedlings under Cd treatments.


Asunto(s)
Cadmio/metabolismo , Glycine max/metabolismo , Raíces de Plantas/crecimiento & desarrollo , Biomasa , Cadmio/análisis , Hidroponía , Raíces de Plantas/química , Raíces de Plantas/metabolismo , Plantones/química , Plantones/crecimiento & desarrollo , Plantones/metabolismo , Glycine max/química , Glycine max/crecimiento & desarrollo
17.
Environ Sci Pollut Res Int ; 22(24): 19584-95, 2015 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-26272289

RESUMEN

The hydroponic experiment was carried out to investigate the Cd subcellular distribution and chemical forms in roots and shoots among four soybean seedling cultivars with two Cd treatments. HX3 and GC8, two tolerant and low-grain-Cd-accumulating cultivars, had the lowest Cd concentration in roots and high Cd concentration in shoots, while BX10 and ZH24, two sensitive and high-grain-Cd-accumulating cultivars, had the highest Cd concentration in roots and the lowest Cd concentration in shoots at young seedling stage. Furthermore, the sequence of Cd subcellular distribution in roots at two Cd levels was cell wall (53.4-75.5 %) > soluble fraction (15.8-40.4 %) > organelle fraction (2.0-14.7 %), but in shoots, was soluble fraction (39.3-74.8 %) > cell wall (16.0-52.0 %) > organelle (4.8-19.5 %). BX10 and ZH24 had higher Cd concentration in all subcellular fractions in roots, but HX3 and GC8 had higher Cd concentration of soluble fraction in shoots. The sequence of Cd chemical forms in roots was FNacl (64.1-79.5 %) > FHAC (3.4-21.5 %) > Fd-H2O (3.6-13.0 %) > Fethanol (1.4-21.8) > FHCl (0.3-1.6 %) > Fother (0.2-1.4 %) at two Cd levels but, in shoots, was FNacl (19.7-51.4 %) ≥ FHAC (10.2-31.4 %) ≥ Fd-H2O (8.8-28.2 %) ≥ Fethanol (8.9-38.6 %) > FHCl (0.2-9.6 %) > Fother (2.5-11.2 %). BX10 and ZH24 had higher Cd concentrations in each extracted solutions from roots, but from shoots for GC8 and HX3. Taken together, the results uncover that root cell walls and leaf vacuoles might play important roles in Cd detoxification and limiting the symplastic movement of Cd.


Asunto(s)
Cadmio/análisis , Glycine max/química , Hojas de la Planta/química , Raíces de Plantas/química , Plantones/química , Contaminantes del Suelo/análisis , Hidroponía , Hojas de la Planta/crecimiento & desarrollo , Hojas de la Planta/ultraestructura , Raíces de Plantas/crecimiento & desarrollo , Raíces de Plantas/ultraestructura , Plantones/crecimiento & desarrollo , Plantones/ultraestructura , Glycine max/crecimiento & desarrollo , Glycine max/ultraestructura , Fracciones Subcelulares/química , Fracciones Subcelulares/ultraestructura
18.
BMC Cardiovasc Disord ; 13: 34, 2013 May 03.
Artículo en Inglés | MEDLINE | ID: mdl-23642232

RESUMEN

BACKGROUND: Aortic dissection(AD) is an acute process of large blood vessels characterized by dangerous pathogenic conditions and high disability and high mortality. The pathogenesis of AD remains debated. Matrix metalloproteinase-12 (MMP-12) participates in many pathological processes such as abdominal aortic aneurysm, atherosclerosis, emphysema and cancer. However, this elastase has rarely been assessed in the presence of AD. The aim of the present study was to investigate the expression of MMP-12 in aortic tissue so as to offer a better understanding of the possible mechanisms of AD. METHODS: The protein expression levels of MMP-12 were analyzed and compared in aorta tissue and the blood serum samples by reverse transcription polymerase chain reaction(RT-PCR), Western blotting, immuno-histochemistry, fluorescence resonance energy transfer ( FRET ) activity assay and enzyme-linked immuno sorbent assay ( ELISA ), respectively. Ascending aorta tissue specimens were obtained from 12 patients with an acute Stanford A-dissection at the time of aortic replacement, and from 4 patients with coronary artery disease (CAD) undergoing coronary artery bypass surgery. Meanwhile, serum samples were harvested from 15 patients with an acute Stanford A-dissection and 10 healthy individuals who served as the control group. RESULTS: MMP-12 activity could be detected in both AD and CAD groups, but the level in the AD group was higher than those in the CAD group (P < 0.05). MMP-12 proteolysis existed in both serum samples of the AD and healthy groups, and the activity level in the AD group was clearly higher than in the healthy group (P < 0.05). For AD patients, MMP-12 activity in serum was higher than in the aorta wall (P < 0.05). MMP-12 activity in the aortic wall tissue can be inhibited by MMP inhibitor v (P < 0.05). CONCLUSION: The present study directly demonstrates that MMP-12 proteolytic activity exists within the aorta specimens and blood samples from aortic dissection patients. MMP-12 might be of potential relevance as a clinically diagnostic tool and therapeutic target in vascular injury and repair.


Asunto(s)
Aneurisma de la Aorta/enzimología , Aneurisma de la Aorta/genética , Disección Aórtica/enzimología , Disección Aórtica/genética , Regulación Enzimológica de la Expresión Génica , Metaloproteinasa 12 de la Matriz/genética , Adulto , Anciano , Disección Aórtica/diagnóstico , Aneurisma de la Aorta/diagnóstico , Femenino , Humanos , Masculino , Metaloproteinasa 12 de la Matriz/biosíntesis , Persona de Mediana Edad , Proteolisis
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...