Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 31
Filtrar
Más filtros












Base de datos
Intervalo de año de publicación
1.
ACS Omega ; 9(18): 20388-20396, 2024 May 07.
Artículo en Inglés | MEDLINE | ID: mdl-38737060

RESUMEN

Among numerous rubbers, high-performance rubber composites can be obtained by mixing fluororubber (FKM) with excellent oil resistance and silicone rubber (SiR) with excellent low-temperature resistance. While the difference in polarity between these two kinds of rubbers leads to a reduction in the properties of the composites. To solve the compatibility problem between the two-phase interfaces in FKM/SiR composites, in this research, fluorinated silicone rubbers (MVQ-g-PFDT) of methyl vinyl silicone rubber (MVQ) grafted with 1H,1H,2H,2H-perfluorodecanethiol (PFDT) were prepared via a facile and efficient thiol-ene click reaction, which was then added into FKM/SiR composites. The results showed that the fluorine-containing side chains could effectively inhibit the low-temperature crystallization phenomenon of silicone rubber and further broaden its application ranges in low-temperature environments. The properties of FKM/SiR composites with the addition of MVQ-g-PFDT were significantly improved, with the highest tensile strength of 14.1 MPa and the lowest mass change rate of 6.71% after 48h immersion at 200 °C in IRM903 oil. Additionally, the hydroxyl groups between the fluorine-containing side chains of MVQ-g-PFDT and the surface of silica facilitate the enhancement of the uniform dispersion of fillers. Atomic force microscopy (AFM) characterization results showed a distinct enhancement of the compatibility between the two phases of FKM and SiR. This work would provide further insight into efforts to improve compatibility between rubbers with widely different polarities.

2.
Nanoscale ; 15(32): 13428-13436, 2023 Aug 17.
Artículo en Inglés | MEDLINE | ID: mdl-37547945

RESUMEN

Polymer composites with good thermal conductivity are gaining more and more attention in the current electronics sector, due to their superior heat management capabilities. However, conventional thermally conductive polymer composites are usually subject to interruptions in heat transfer because of physical damage. The present study prepared mechanical property-enhanced thermally-conductive self-healing composites through compositing a self-healing polyurethane matrix with hydroxylated boron nitride (hyBNNSs). The self-healing polyurethane was obtained by incorporating ligands and cerium(III) triflate [Ce(SO3CF3)3] as the metal center into the polyurethane elastomer. An optimal sample (PUp2C) with high tensile strength (6.8 MPa) and stretchability (1053%), ideal toughness (49.2 MJ m-3), and remarkable healing efficiency (97% healing after 48 h at 35 °C) was obtained. An increase in the content of hyBNNSs from 10% to 30% led to a significant increase in the mechanical performance of hyBNNSs20%/PUp2C, which manifested as the increase in the elongation at break (from 1053% to 1302.5%) and stress (from 6.8 MPa to 16.4 MPa). The XRD results revealed that combining PU with hyBNNSs through coordination bonds could significantly promote the crystallization of PUp2C, which was beneficial to enhancing the mechanical properties of the composites. The through-plane (λ⊥) and the in-plane (λ∥) values of the BNNSs30%/PUp2C composite reached 0.41 and 1.42 W mK-1, respectively, which were 195.2% and 507.1% higher than those of the original PUp2C, respectively.

3.
Chemosphere ; 339: 139768, 2023 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-37567258

RESUMEN

Arbuscular mycorrhizal fungi (AMF) can alleviate heavy metal phytotoxicity and promote plant growth, while the underlying mechanisms of AMF symbiosis with host plants under manganese (Mn) stress remain elusive. A pot experiment was carried out to investigate the plant growth, micro-structure, Mn accumulation, subcellular distribution, chemical forms, and physiological and biochemical response of Rhus chinensis inoculated with Funneliformis mosseae (FM) under different Mn treatments. The results showed that compared with plants without FM, FM-associated plants exhibited higher growth status, photosynthetic pigments, and photosynthesis under Mn stress. FM-associated plants were able to maintain greater integrity in mesophyll structure, higher thickness of leaf, upper epidermis, and lower epidermis under Mn treatment, and promote leaf growth. Mn accumulation in leaves (258.67-2230.50 mg kg-1), stems (132.67-1160.00 mg kg-1), and roots (360.92-2446.04 mg kg-1) of the seedlings inoculated with FM was higher than non-inoculated ones. FM-associated plants exhibited higher osmotic regulating substances and antioxidant enzymes' activities under Mn exposure, suggesting lower Mn toxicity in FM inoculated seedlings, despite the augment in Mn accumulation. After FM inoculation, Mn concentration (151.04-1211.32 mg kg-1) and percentage (64.41-78.55%) enhanced in the cell wall, whilst the transport of Mn to aerial plant organs decreased. Furthermore, FM symbiosis favored the conversion of Mn from high toxic forms (2.17-15.68% in FEthanol, 11.37-24.52% in Fdeionized water) to inactive forms (28.30-38.15% in FNaCl, 18.07-28.59% in FHAc, 4.41-17.99% in FHCl) with low phytotoxicity. Our study offers a theoretical basis for remediation of the FM- R. chinensis symbiotic system in Mn-contaminated environments.


Asunto(s)
Micorrizas , Rhus , Micorrizas/metabolismo , Manganeso/toxicidad , Manganeso/metabolismo , Rhus/metabolismo , Raíces de Plantas/metabolismo , Plantones/metabolismo , Antioxidantes/metabolismo
4.
Ecol Process ; 12(1): 23, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37220562

RESUMEN

Background: China's 35 largest cities, including Wuhan, are inhabited by approximately 18% of the Chinese population, and account for 40% energy consumption and greenhouse gas emissions. Wuhan is the only sub-provincial city in Central China and, as the eighth largest economy nationwide, has experienced a notable increase in energy consumption. However, major knowledge gaps exist in understanding the nexus of economic development and carbon footprint and their drivers in Wuhan. Methods: We studied Wuhan for the evolutionary characteristics of its carbon footprint (CF), the decoupling relationship between economic development and CF, and the essential drivers of CF. Based on the CF model, we quantified the dynamic trends of CF, carbon carrying capacity, carbon deficit, and carbon deficit pressure index from 2001 to 2020. We also adopted a decoupling model to clarify the coupled dynamics among total CF, its accounts, and economic development. We used the partial least squares method to analyze the influencing factors of Wuhan's CF and determine the main drivers. Results: The CF of Wuhan increased from 36.01 million t CO2eq in 2001 to 70.07 million t CO2eq in 2020, a growth rate of 94.61%, which was much faster than that of the carbon carrying capacity. The energy consumption account (84.15%) far exceeded other accounts, and was mostly contributed by raw coal, coke, and crude oil. The carbon deficit pressure index fluctuated in the range of 8.44-6.74%, indicating that Wuhan was in the relief zone and the mild enhancement zone during 2001-2020. Around the same time, Wuhan was in a transition stage between weak and strong CF decoupling and economic growth. The main driving factor of CF growth was the urban per capita residential building area, while energy consumption per unit of GDP was responsible for the CF decline. Conclusions: Our research highlights the interaction of urban ecological and economic systems, and that Wuhan's CF changes were mainly affected by four factors: city size, economic development, social consumption, and technological progress. The findings are of realistic significance in promoting low-carbon urban development and improving the city's sustainability, and the related policies can offer an excellent benchmark for other cities with similar challenges. Supplementary Information: The online version contains supplementary material available at 10.1186/s13717-023-00435-y.

5.
Org Lett ; 24(10): 2020-2024, 2022 03 18.
Artículo en Inglés | MEDLINE | ID: mdl-35263540

RESUMEN

A visible-light-promoted atomic substitution reaction for transforming thiocacids into carboxylic acids with dimethyl sulfoxide (DMSO) as the oxygen source has been developed, affording various alkyl and aryl carboxylic acids in over 90% yields. The atomic substitution process proceeds smoothly through the photochemical reactivity of the formed hydrogen-bonding adduct between thioacids and DMSO. A DMSO-involved proton-coupled electron transfer (PCET) and the simultaneous generation of thiyl and hydroxyl radicals are proposed to be key steps for realizing the transformation.


Asunto(s)
Ácidos Carboxílicos , Dimetilsulfóxido , Transporte de Electrón , Oxidación-Reducción , Protones , Compuestos de Azufre
6.
Clin Breast Cancer ; 22(2): e173-e183, 2022 02.
Artículo en Inglés | MEDLINE | ID: mdl-34272173

RESUMEN

BACKGROUND: The platelet derived growth factor-D (PDGF-D) plays an important role in breast tumor aggressiveness. However, limited study has investigated the effect of silencing PDGF-D on the biological function of breast cancer. The purpose of this study is to clarify the potential value of PDGF-D as a target for breast cancer treatment. METHODS: Reverse transcription-polymerase chain reaction and western blot were used to detect PDGF-D expression in 5 different breast cancer cells. The lentiviral vector was usd to silence PDGF-D in MDA-MB-231 cells. Then, Methyl Thiazolyl Tetrazolium was used to detect cell viability, 5-Ethynyl-2'- deoxyuridine and a soft agar assay were used to detect cell proliferation and clonality. Additionally, cell apoptosis after PDGF-D knockdown was measured by Annexin V/ Prodium Iodide staining, and cell migration was detected by trans-well assay. Survival rate and tumor size were measured by nude mice transplantation. RESULTS: The MDA-MB-231 and SK-BR-3 cell lines showed higher PDGF-D expression than the MCF7 cell lines (P<.05). After the PDGF-D gene was silenced, the growth and colony forming abilitys ignificantly decreased (P<.05) together with the induction of apoptosis in MDA-MB-231 cells (P<.05). Moreover, MDA-MB-231 cells with PDGF-D silencing showed significantly diminished aggressive migration and invasion potential compared to other cells (P<.05). In vivo experiments also indicated that PDGF-D silencing inhibited tumor growth and improved the survival rate of tumor-bearing mice. CONCLUSION: Downregulation of PDGF-D had dramatic effects on breast cancer cell proliferation, apoptosis and migration, which indicates that it plays an important role in breast cancer development and progression.


Asunto(s)
Neoplasias de la Mama/patología , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Linfocinas/metabolismo , Factor de Crecimiento Derivado de Plaquetas/metabolismo , Apoptosis/efectos de los fármacos , Neoplasias de la Mama/metabolismo , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Regulación hacia Abajo/efectos de los fármacos , Femenino , Humanos , ARN Mensajero/metabolismo
7.
Asian J Androl ; 24(4): 373-379, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-34747721

RESUMEN

This paper presents a meta-analysis regarding the detection rate (DR) of fluorine-18 (18F)-labeled prostate-specific membrane antigen positron emission tomography/computed tomography (PSMA PET/CT) in the management of patients with prostate cancer (PCa). Relevant studies regarding 18F-PSMA PET/CT in the management of PCa published until June 1, 2021, were electronically searched in online databases including EMBASE, PubMed, and Web of Science. The primary outcome was the DR of 18F-PSMA PET/CT in managing PCa patients, while the secondary outcome was the DR of 18F-PSMA PET/CT according to Gleason scores and serum prostate-specific antigen (PSA) level. The pooled DR was calculated on a per-patient basis, with pooled odd ratios and 95% confidence intervals (CIs). In total, 17 observational studies evaluating 1019 patients with PCa met the inclusion criteria. The DR of 18F-PSMA PET/CT was 0.83 (95% CI: 0.78-0.88), in the random-effects model. Subsequently, the analysis of DR of 18F-PSMA PET/CT in PCa patients using Gleason score (≤7 vs ≥8), showed a significant difference in PCa patients. Based on the above results, the higher Gleason score of PCa patients, the higher DR of 18F-PSMA PET/CT. The DR of 18F-PSMA PET/CT in PCa was 0.57 for PSA <0.5 ng ml-1; 0.75 for PSA ≥0.5 ng ml-1 and <1.0 ng ml-1; 0.93 for PSA ≥1.0 ng ml-1 and <2.0 ng ml-1; and 0.95 for PSA ≥2.0 ng ml-1. Therefore, the significant diagnostic value was found in terms of the DR of 18F-PSMA PET/CT in managing PCa patients and was associated with Gleason score and serum PSA level.


Asunto(s)
Tomografía Computarizada por Tomografía de Emisión de Positrones , Neoplasias de la Próstata , Radioisótopos de Flúor , Humanos , Masculino , Clasificación del Tumor , Tomografía Computarizada por Tomografía de Emisión de Positrones/métodos , Antígeno Prostático Específico , Neoplasias de la Próstata/diagnóstico por imagen
8.
Polymers (Basel) ; 15(1)2022 Dec 25.
Artículo en Inglés | MEDLINE | ID: mdl-36616426

RESUMEN

Tires are often in service under dynamic conditions. Realizing the high-precision prediction of the mechanical response of rubber materials under cyclic loading can provide guidance for the design of high-performance tires. In this work, the tensile recovery stress-strain responses of rubber materials in nine different components of a truck and bus radial (TBR) tire were obtained through experiments. Before fitting, an experimental data processing method was proposed to facilitate the parameter identification for a hyper-pseudo-viscoelastic model, that is, the raw experimental data were changed to the adjusted test data. The HyperFit software was used to fit the adjusted test data based on the Yeoh hyperelastic model and the Ogden-Roxburgh pseudoelastic model to obtain the initial material parameters for the two models. In order to describe the permanent set, the Prony series viscoelastic model was introduced. The Isight software was adopted to optimize the parameters. The results showed that the hyper-pseudo-viscoelastic model (i.e., the combination of Yeoh, Ogden-Roxburgh and Prony series models) can describe the tensile recovery mechanical responses (loading curve, unloading curve and permanent set) of nine different rubber components in TBRs. The fitting results are in good agreement with the adjusted data, and all the coefficients of determination (R2) exceed 0.975. Finally, the cyclic deformation simulation of a dumbbell rubber specimen was carried out based on the above constitutive model and fitted parameters. R2 was used to describe the simulation accuracy and its value reached 0.968.

9.
Curr Biol ; 31(9): 1893-1902.e5, 2021 05 10.
Artículo en Inglés | MEDLINE | ID: mdl-33705720

RESUMEN

Although general anesthesia (GA) enables patients to undergo surgery without consciousness, the precise neural mechanisms underlying this phenomenon have yet to be identified. In addition to many studies over the past two decades implicating the thalamus, cortex, brainstem, and conventional sleep-wake circuits in GA-induced loss of consciousness (LOC), some recent studies have begun to highlight the importance of other brain areas as well. Here, we found that population activities of neurons expressing dopamine D1 receptor (D1R) in the nucleus accumbens (NAc), a critical interface between the basal ganglia and limbic system, began to decrease before sevoflurane-induced LOC and gradually returned after recovery of consciousness (ROC). Chemogenetic activation of NAcD1R neurons delayed induction of and accelerated emergence from sevoflurane GA, whereas chemogenetic inhibition of NAcD1R neurons exerted opposite effects. Moreover, transient activation of NAcD1R neurons induced significant cortical activation and behavioral emergence during continuous steady-state GA with sevoflurane or deep anesthesia state with constant and stable burst-suppression oscillations. Taken together, our findings uncover that NAcD1R neurons modulated states of consciousness associated with sevoflurane GA and may represent an area for targeting GA-induced changes in consciousness and ameliorating related adverse effects.


Asunto(s)
Anestesia , Núcleo Accumbens , Estado de Conciencia , Humanos , Neuronas/metabolismo , Núcleo Accumbens/metabolismo , Receptores de Dopamina D1/genética , Receptores de Dopamina D1/metabolismo , Sevoflurano , Inconsciencia
10.
Chem Commun (Camb) ; 56(51): 6907-6924, 2020 Jun 25.
Artículo en Inglés | MEDLINE | ID: mdl-32478341

RESUMEN

The 1,n-enyne annulation reaction has emerged as one of the most powerful and straightforward tools to build carbo- and hetero-cyclic frameworks that are found in numerous natural products, pharmaceuticals and functional materials. Although the 1,n-enyne annulation methods have been well documented to date, there is a tremendous challenge with current methodologies for simultaneously incorporating external functional groups into the resulting cyclic systems. Recent advances in the radical-mediated oxidative 1,n-enyne annulation strategy involving C-H functionalization have been proven to be an ideal alternative to overcome these disadvantages. Such radical-mediated oxidative 1,n-enyne annulation can be accomplished by two different C-H functionalization modes: One proceeds through generation of the carbon-centered radicals from C-H bond direct oxidative cleavage and their subsequent addition across the C[double bond, length as m-dash]C bond or C[triple bond, length as m-dash]C bond enabling the 1,n-enyne annulation; the other employs the C-H bonds as the radical acceptors to terminate the initial oxidative radical-triggered annulation of 1,n-enyne. In addition, during many annulation processes the inherent C-H bonds of 1,n-enynes were functionalized. Here, we summarize recent progress in radical-mediated oxidative annulations of 1,n-enynes involving two different conceptual C-H functionalization strategies and the inherent C-H functionalization with an emphasis on the scope, limitations and mechanisms of these different reactions.

11.
Ecotoxicol Environ Saf ; 198: 110696, 2020 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-32380306

RESUMEN

Cleome viscosa L. is a promising species for the phytoremediation of Mn-contaminanted soil. To reveal the adaptive mechanisms of species to Mn stress, plant growth, Mn subcellular distribution, Mn chemical forms, and plant physiological and biochemical traits were characterized in plants grown under different concentrations of Mn2+ (0, 1000, 5000, 10000, 15000 and 20000 µM). The results showed that C. viscosa plant biomass initially increased and then decreased with rising Mn treatment concentration. C. viscosa plants can accumulate high levels of Mn in roots and leaves, and both the bioconcentration factor (BCF) and the translocation factor (TF) exhibited values higher than one. Mn was primarily retained in the cell wall and soluble fractions. Predominant chemical forms of Mn were pectate and protein, phosphates, and oxalates-integrated Mn. The activities of antioxidant enzymes, including superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and the contents of proline, soluble sugar, and soluble protein initially increased and then decreased with enhancing Mn treatment concentration, whereas the malondialdehyde (MDA) content simultaneously displayed a gradual increase. Combined, these results indicate that C. viscosa can tolerate Mn-stress conditions by increasing antioxidant enzyme activities and non-enzymatic metabolites contents. In addition, Mn immobilization in the cell wall and soluble fractions, alongside the storage of Mn in low-activity chemical forms are further important mechanisms to cope with high environmental Mn concentration. This study reveals the adaptive mechanisms of plants to Mn stress, and provides a theoretical basis for the use of C. viscosa as a candidate phytoremediation plant for Mn-contaminated soil.


Asunto(s)
Cleome/fisiología , Manganeso/toxicidad , Contaminantes del Suelo/toxicidad , Antioxidantes/metabolismo , Biodegradación Ambiental , Biomasa , Catalasa/metabolismo , Cleome/metabolismo , Malondialdehído/metabolismo , Manganeso/metabolismo , Peroxidasa/metabolismo , Peroxidasas/metabolismo , Desarrollo de la Planta , Hojas de la Planta/metabolismo , Raíces de Plantas/metabolismo , Suelo/química , Contaminantes del Suelo/análisis , Superóxido Dismutasa/metabolismo
12.
iScience ; 20: 229-236, 2019 Oct 25.
Artículo en Inglés | MEDLINE | ID: mdl-31590075

RESUMEN

A new strategy for the synthesis of conjugated (E,E)-dienones and (E,E)-dienals via a palladium-catalyzed aerobic γ,δ-dehydrogenation of enones and enals has been developed. The method can be employed in the direct and efficient synthesis of various (E,E)-dienones and (E,E)-dienals, including non-substituted α-, ß-, and γ- and/or δ-substituted (E,E)-dienones and (E,E)-dienals. The protocol is featured by the ready accessibility and elaboration of the starting materials, good functional group compatibility, and mild reaction conditions. Furthermore, the reaction is of complete E,E-stereoselectivity and uses molecular oxygen as the sole clean oxidant.

13.
Chemosphere ; 237: 124531, 2019 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-31404737

RESUMEN

Xanthium strumarium L. is a candidate species for manganese (Mn)-phyto-remediation. To reveal the mechanism of this species adaptive to Mn stress, the growth, Mn subcellular distribution, chemical forms, as well as micro-structure and ultra-structure responses of the mining ecotype (ME) of X. strumarium to Mn stress were studied with the non-mining ecotype (NME) as the reference by a hydroponic experiment. The results showed the ME demonstrated a higher tolerance to Mn stress with a superior growth and a higher tolerance index (TI) when compared with the NME. The concentrations of Mn in leaves, stems, and roots of the ME were 1.1-1.8, 1.2-1.9, and 1.3-1.9 times higher than those in the corresponding organs of the NME, respectively. The micro-structure and ultra-structure showed abnormal alterations, such as shrunken ducts and sieve canals, round-shaped chloroplasts, increased starch and osmiophilic granules, as well as expanded and non-compact granum thylakoids in the NME, compared to the ME. More than 83% of Mn was localized in cell wall and soluble fraction, while the Mn concentration in all fractions had a direct linear relationship with Mn treatment in the ME. The proportions of pectates and protein integrated-Mn, phosphate-Mn, and oxalate-Mn forms were dominant in leaves and stems of the ME, whereas, in the NME the relative proportions of inorganic Mn and water-soluble Mn forms in the roots was higher than the other forms. Altogether, the combination of preferential distribution of Mn in the cell wall and soluble fraction, and storage of Mn in low toxicity forms, such as phosphate-Mn, pectates and protein-bound Mn, and oxalate-Mn, might be responsible for alleviating Mn toxicity in the ME.


Asunto(s)
Manganeso/metabolismo , Contaminantes del Suelo/metabolismo , Xanthium/fisiología , Pared Celular/metabolismo , Hidroponía , Inactivación Metabólica , Manganeso/análisis , Minería , Hojas de la Planta/metabolismo , Raíces de Plantas/metabolismo , Contaminantes del Suelo/análisis
14.
Ecotoxicol Environ Saf ; 181: 455-462, 2019 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-31228821

RESUMEN

Macleaya cordata is a perennial herb, a candidate phytoremediation plant with high biomass and manganese (Mn) tolerance. To study the mechanism underlying its Mn adaptability, Mn2+ at various concentrations (0, 1000, 5000, 10000, 15000, and 20000 µM) were applied to M. cordata to investigate the subcellular distribution and chemical forms of Mn, as well as the resulting physiological and biochemical changes by pot culture experiment under natural light in a greenhouse. According to our results, Mn level in M. cordata increased with exogenous Mn concentrations; and Mn contents in different tissues exhibited a leaf > root > stem pattern. Meanwhile, biomass and the level of photosynthetic pigments increased at lower Mn concentrations but declined as Mn concentration further ascended. Subcellular distribution analysis revealed that Mn was sequestered in cell wall and vacuole; in addition, it was incorporated into pectates and protein, phosphates, and oxalates. These findings revealed a possible effective strategy for M. cordata to reduce Mn mobility and toxicity. Moreover, a continuous boost in the level of malondialdehyde was observed with Mn gradient; whereas contents of soluble proteins and proline, and the activities of superoxide dismutase and peroxidase were initially increased and then dropped. Altogether, these results indicated that most Mn was trapped in the cell wall and soluble fractions in low toxicity forms such as pectates and protein, phosphates, and oxalates. These strategies, that is functioning cooperatively with the well-coordinated antioxidant defense systems and the non-enzymatic metabolites, confer strong resistance to Mn in M. cordata.


Asunto(s)
Adaptación Fisiológica , Contaminantes Ambientales/metabolismo , Manganeso/metabolismo , Papaveraceae/fisiología , Antioxidantes/metabolismo , Biodegradación Ambiental , Biomasa , Pared Celular/metabolismo , Papaveraceae/enzimología , Papaveraceae/metabolismo , Fotosíntesis , Vacuolas/metabolismo
15.
Org Lett ; 21(8): 2731-2735, 2019 04 19.
Artículo en Inglés | MEDLINE | ID: mdl-30916984

RESUMEN

An unprecedented cross-dehydrogenative-coupling (CDC) reaction of saturated aldehyde ß-C-H with arenes to form cinnamaldehydes via the cleavages of four C-H bonds has been developed. The reaction possesses complete E-stereoselectivity for the C═C double bond. The protocol is featured by atom and step economy, mild reaction conditions, and convenient operation.

16.
Ecotoxicol Environ Saf ; 172: 308-316, 2019 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-30716666

RESUMEN

Xanthium strumarium is an annual pseudometallophyte. To reveal the mechanisms of this species to adapt to metallicolous environmental conditions, phenological traits and biomass allocation of metallicolous and non-metallicolous populations of X. strumarium under six Mn2+ concentrations by pot culture experiments were performed. The results showed that both time to bolting and time to fruit setting in the metallicolous population were earlier than those in the non-metallicolous population. The number of flowers, fruits, seeds and 1000-seed weight in the metallicolous population were higher than those in the non-metallicolous population under Mn stress. Reproductive allocation and harvest index in the metallicolous population were higher than those in the non-metallicolous population. Furthermore, all the Mn concentrations in leaves, stems, roots, and fruits of the metallicolous population were higher than the counterparts of non-metallicolous population. These results suggested that metallicolous population had higher tolerance to Mn stress than non-metallicolous population, the earlier flowering and fruiting, and the enhancement in reproductive allocation may contribute to plant tolerance to Mn toxicity for X. strumarium.


Asunto(s)
Manganeso/toxicidad , Estrés Fisiológico/efectos de los fármacos , Xanthium/química , Biomasa , Flores/química , Flores/efectos de los fármacos , Frutas/química , Frutas/efectos de los fármacos , Germinación/efectos de los fármacos , Hojas de la Planta/química , Hojas de la Planta/efectos de los fármacos , Raíces de Plantas/química , Raíces de Plantas/efectos de los fármacos , Semillas/química , Semillas/efectos de los fármacos , Contaminantes del Suelo/toxicidad , Xanthium/efectos de los fármacos
17.
Ecotoxicol Environ Saf ; 165: 654-661, 2018 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-30245299

RESUMEN

Effective phytoremediation of manganese (Mn) requires the careful selection of a species that has a relatively high manganese tolerance. Exploring the physiological mechanisms related to Mn stress responses is crucial for identifying and employing species for Mn phytoremediation. Xanthium strumarium is a species that can accumulate high levels of Mn, thus it is a candidate species for Mn-phytoremediation. To reveal the tolerance mechanisms of this species to manage Mn stress, the morphological, physiological, and biochemical responses of seedlings grown in water cultures under six different Mn concentrations were analyzed. The results showed that X. strumarium can accumulate high levels of Mn, even as plant growth was inhibited by rising Mn concentrations. Malondialdehyde (MDA) content increased and catalase (CAT) activity decreased along with the increased Mn concentrations, while soluble protein and proline content, as well as the superoxide dismutase (SOD) and peroxidase (POD) enzymes, all increased initially and then declined. The highest value of POD, SOD, soluble protein and proline all occurred at 5000 µM of Mn stress, which means that X. strumarium can adapt to low concentration of Mn stress. The net photosynthetic rate (Pn), stomatal conductance (Gs), intercellular CO2 concentration (Ci) and transpiration rate (Tr) decreased, and the stomatal limitation (Ls) increased in response to Mn stress. Furthermore, water use efficiency (WUE) and intrinsic water use efficiency (WUEi) increased first under low concentration of Mn, and then reduced as the concentration of Mn increased. The maximum quantum efficiency of PSII photochemistry (Fv/Fm), efficiency of excitation capture by open PSII reaction centers (Fv'/Fm'), electron transport rate (ETR) declined as Mn concentration increased. In conclusion, the above results showed that X. strumarium can be effectively used for phytoremediation of Mn-contaminated soils.


Asunto(s)
Manganeso/toxicidad , Contaminantes del Suelo/toxicidad , Xanthium/efectos de los fármacos , Transporte de Electrón/efectos de los fármacos , Malondialdehído/metabolismo , Manganeso/metabolismo , Oxidación-Reducción , Oxidorreductasas/metabolismo , Peroxidasa/metabolismo , Peroxidasas/metabolismo , Fotosíntesis/efectos de los fármacos , Plantones/efectos de los fármacos , Contaminantes del Suelo/metabolismo , Estrés Fisiológico , Superóxido Dismutasa/metabolismo , Xanthium/metabolismo
18.
Sci Rep ; 8(1): 11646, 2018 08 03.
Artículo en Inglés | MEDLINE | ID: mdl-30076350

RESUMEN

With the development of next generation sequencing, more and more common inherited diseases have been reported. However, accurate and convenient molecular diagnosis cannot be achieved easily because of the enormous size of disease causing mutations. In this study, we introduced a new single-step method for the genetic analysis of patients and carriers in real clinical settings. All kinds of disease causing mutations can be detected at the same time in patients with Mendelian diseases or carriers. First, we evaluated this technology using YH cell line DNA and 9 samples with known mutations. Accuracy and stability of 99.80% and 99.58% were achieved respectively. Then, a total of 303 patients were tested using our targeted NGS approaches, 50.17% of which were found to have deleterious mutations and molecular confirmation of the clinical diagnosis. We identified 219 disease causing mutations, 43.84% (96/219) of which has never been reported before. Additionally, we developed a new deleteriousness prediction method for nonsynonymous SNVs, and an automating annotation and diagnosis system for Mendelian diseases, thus greatly assisting and enhancing Mendelian diseases diagnosis and helping to make a precise diagnosis for patients with Mendelian diseases.


Asunto(s)
Enfermedades Genéticas Congénitas/diagnóstico , Enfermedades Genéticas Congénitas/genética , Pruebas Genéticas , Secuenciación de Nucleótidos de Alto Rendimiento , Estudios de Cohortes , Enfermedades Genéticas Congénitas/clasificación , Heterocigoto , Humanos , Mutación/genética , Polimorfismo de Nucleótido Simple/genética , Análisis de Secuencia de ADN , Secuenciación del Exoma , Secuenciación Completa del Genoma
19.
Org Lett ; 20(7): 1794-1797, 2018 04 06.
Artículo en Inglés | MEDLINE | ID: mdl-29522346

RESUMEN

The utilization of the transient directing strategy into the direct oxidative dehydrogenative arylation of aldehydes with arenes was reported for the first time. Featured by mild reaction conditions, good functional group compatibility, and great regioselectivity, the method should find broad applications in new medicine and material development and discovery processes.

20.
Org Lett ; 20(7): 1910-1913, 2018 04 06.
Artículo en Inglés | MEDLINE | ID: mdl-29522348

RESUMEN

A new chemistry of azo compounds that is a radical generation and addition in situ of azocarboxylic tert-butyl esters to synthesize hydrazines has been described. The protocol provides a novel strategy for the synthesis of various hydrazines. The advantages of the transformation include broad substrate scope, benign conditions, and convenient operation.

SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...