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1.
Nano Lett ; 2024 Jun 17.
Artículo en Inglés | MEDLINE | ID: mdl-38885458

RESUMEN

The metal-semiconductor interface fabricated by conventional methods often suffers from contamination, degrading transport performance. Herein, we propose a one-pot chemical vapor deposition (CVD) process to create a two-dimensional (2D) MoO2-MoSe2 heterostructure by growing MoO2 seeds under a hydrogen environment, followed by depositing MoSe2 on the surface and periphery. The ultraclean interface is verified by cross-sectional scanning transmission electron microscopy and photoluminescence. Along with the high work function of semimetallic MoO2 (Ef = -5.6 eV), a high-rectification Schottky diode is fabricated based on this heterostructure. Furthermore, the Schottky diode exhibits an excellent photovoltaic effect with a high open-circuit voltage of 0.26 eV and ultrafast photoresponse, owing to the naturally formed metal-semiconductor contact with suppressed pinning effect. Our method paves the way for the fabrication of an ultraclean 2D metal-semiconductor interface, without defects or contamination, offering promising prospects for future nanoelectronics.

2.
Nano Lett ; 23(23): 11034-11042, 2023 Dec 13.
Artículo en Inglés | MEDLINE | ID: mdl-38038404

RESUMEN

WSe2 has a high mobility of electrons and holes, which is an ideal choice as active channels of electronics in extensive fields. However, carrier-type tunability of WSe2 still has enormous challenges, which are essential to overcome for practical applications. In this work, the direct growth of n-doped few-layer WSe2 is realized via in situ defect engineering. The n-doping of WSe2 is attributed to Se vacancies induced by the H2 flow purged in the cooling process. The electrical measurements based on field effect transistors demonstrate that the carrier type of WSe2 synthesized is successfully transferred from the conventional p-type to the rarely reported n-type. The electron carrier concentration is efficiently modulated by the concentration of H2 during the cooling process. Furthermore, homomaterial inverters and self-powered photodetectors are fabricated based on the doping-type-tunable WSe2. This work reveals a significant way to realize the controllable carrier type of two-dimensional (2D) materials, exhibiting great potential in future 2D electronics engineering.

3.
Langmuir ; 39(38): 13503-13511, 2023 Sep 26.
Artículo en Inglés | MEDLINE | ID: mdl-37705201

RESUMEN

Nanofiltration polyamide (NF PA) membranes are widely used in seawater desalination and wastewater treatment due to their excellent permeability. The structure-activity relationship of PA membranes has attracted extensive attention in decades. In this work, NF PA membranes with planar structure, nodular structure, and peak-valley structure were constructed, and the pure water permeance was calculated by nonequilibrium molecular dynamics simulation to quantitatively investigate the structure-activity relationship between the microstructure and water permeance. Results showed that the peak-valley structure had the highest effective utilization rate of the membrane surface, which had the highest number of water molecules that passed through membranes per unit cross-sectional area (7.09). Furthermore, with the increase of the specific surface area ratio, the water permeance of the NF PA with peak-valley increased at a rate about 2.5 times than that of the planar NF PA. Therefore, some molecular scale insights were supplied about the structure-activity relationship of NF PA membranes, which is helpful for the fabrication of high-performance NF PA membranes.

4.
Environ Sci Technol ; 57(14): 5999-6007, 2023 04 11.
Artículo en Inglés | MEDLINE | ID: mdl-36996327

RESUMEN

A free-standing polyamide (PA) film is fabricated via in situ release from a thin-film composite (TFC) membrane achieved through the removal of the polysulfone support. The structure parameter S of the PA film is measured to be 24.2 ± 12.6 µm, which is about 87-fold of its film thickness. A significant decline in water flux of the PA film from an ideal forward osmosis membrane is observed. We find that the decline is predominantly influenced by the internal concentration polarization (ICP) of the PA film based on our experimental measurements and theoretical calculations. We propose that the asymmetric hollow structures of the PA layer with dense crusts and cavities may be the underlying cause of the occurrence of the ICP. More importantly, the structure parameter of the PA film can be reduced and its ICP effect can be mitigated by tuning its structures with fewer and shorter cavities. Our results for the first time provide experimental evidence to prove that the PA layer of the TFC membrane has the ICP effect, which could potentially provide fundamental insights into the influence of structural properties of PA on the membrane separation performance.


Asunto(s)
Nylons , Purificación del Agua , Nylons/química , Membranas Artificiales , Ósmosis , Agua/química , Purificación del Agua/métodos
5.
BMC Plant Biol ; 22(1): 43, 2022 Jan 21.
Artículo en Inglés | MEDLINE | ID: mdl-35062882

RESUMEN

In desert habitats, sand burial is an important factor affecting germination of plant seeds and seedling growth. Xanthium spinosum has strong adaptability in arid desert areas, and is a common malignant invasive plant in Xinjiang, China. The effects of different sand burial depths on seed germination, seedling emergence, growth and biomass allocation were studied to provide a scientific basis for further control of X. spinosum. Six sand burial depths (1, 2, 3, 5, 7 and 9 cm) were established to explore the response of X. spinosum seed germination and seedling growth to sand burial. The first emergence time, peak emergence time, emergence rate, seedling growth height, biomass and biomass distribution of X. spinosum seeds was significantly different at sand burial depths (P < 0.05). The X. spinosum seeds had the highest emergence rate (71.5%) at 1 cm sand burial and the maximum seedling height (7.1 cm). As sand burial depth increased, the emergence rate and seedling height gradually decreased. Emergence rate (12.25%) and seedling height (2.9 cm) were lowest at 9 cm sand burial. The root length at 9 cm depth (13.6 cm) was significantly higher than that at other sand depths (P < 0.05). The sand burial depth affected the biomass accumulation and distribution of X. spinosum. As sand burial depth increased, the root biomass and rhizome ratio increased, and the most deeply buried seedlings allocated more biomass for root growth. The optimal sand burial depth for seed germination and seedling growth of X. spinosum was 1-3 cm, and high burial depth (5-9 cm) was not conducive to the germination and growth of X. spinosum seedlings. For prevention and control of X. spinosum, we suggest deeply ploughing crops before sowing to ensure X. spinosum seeds are ploughed into a deep soil layer.


Asunto(s)
Arena , Plantones/crecimiento & desarrollo , Semillas/crecimiento & desarrollo , Xanthium/crecimiento & desarrollo , Biomasa , China , Germinación/fisiología , Especies Introducidas
6.
Langmuir ; 38(51): 16094-16103, 2022 12 27.
Artículo en Inglés | MEDLINE | ID: mdl-36512334

RESUMEN

N-Oxide zwitterionic polyethyleneimine (ZPEI), a new kind of aqueous phase monomer synthesized by commercially branched polyethyleneimine (PEI) via oxidation reaction, was prepared for fabrication of thin-film composite (TFC) polyamide membranes via interfacial polymerization. The main factors, including the monomer concentration and immersion time of the aqueous phase and organic phase, were investigated. Compared with PEI-TFC membranes, the obtained optimal defect-free ZPEI-TFC membranes exhibited a lower roughness (3.3 ± 0.3 nm), a better surface hydrophilicity, and a smaller pore size (238 Da of MWCO). The positively charged ZPEI-TFC membranes (isoelectric point at pH 8.05) showed higher rejections toward both divalent cationic (MgCl2, 93.0%) and anionic (Na2SO4, 96.1%) salts with a water permeation flux of up to 81.0 L·m-2·h-1 at 6 bar, which surpassed currently reported membranes. More importantly, mainly owing to N-oxide zwitterion with strong hydration capability, ZPEI-TFC membranes displayed a high flux recovery ratio (97.0%) toward a model protein contaminant (bovine serum albumin), indicating good anti-fouling properties. Therefore, the novel N-oxide zwitterion functionalized positively charged nanofiltration membranes provide an alternative for water desalination and sewage reclamation.


Asunto(s)
Nylons , Óxidos , Nylons/química , Polietileneimina , Membranas Artificiales , Agua/química
7.
Clin Exp Rheumatol ; 40(11): 2125-2132, 2022 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-35084324

RESUMEN

OBJECTIVES: Our previous studies found that serum leptin was increased significantly in SLE, characterised by dysregulated autoreactive B cells producing excessive inflammatory cytokines and autoantibodies. The aim of this study was to explore the effects of leptin on B cell functions in SLE and clarify the key pathways in leptin dysregulated B cells. METHODS: Peripheral blood samples were obtained from 86 SLE patients and 28 normal controls. Purified B cells were stimulated with leptin or SLE serum and with or without anti-leptin antibody. The frequencies of CD19-CD138+ plasma cells and the expression of leptin receptor (LEPR) on B cells were determined with flow cytometry. The levels of antibodies and cytokines were assayed by ELISA. Classic signalling pathways were detected with western blotting method. RESULTS: Increased plasma cells and the levels of IgG and anti-dsDNA antibodies were positively correlated with serum leptin in SLE patients. LEPR+CD19+B cells were increased in SLE patients. Leptin up-regulated LEPR on B cells and activated B cells to produce higher levels of IL-6, IL-10 and TNF-α, and induced B cells to differentiated into plasma cells secreting more IgG and IgM. More importantly, anti-leptin neutralising antibody could partially restore increased cytokines, antibodies and plasma cells induced by SLE serum. Mechanistically, both leptin and SLE serum activated JAK/STAT3/5 and ERK1/2 signalling pathways in B cells, and the secretion-enhancing effects were restored by their inhibitors. CONCLUSIONS: Leptin may be a key factor leading to B cell dysfunction by activating JAK/STAT3/5 and ERK1/2 signalling pathways in SLE.


Asunto(s)
Linfocitos B , Leptina , Lupus Eritematoso Sistémico , Sistema de Señalización de MAP Quinasas , Humanos , Antígenos CD19 , Citocinas , Inmunoglobulina G , Factor de Transcripción STAT3 , Linfocitos B/citología
8.
Angew Chem Int Ed Engl ; 61(46): e202212816, 2022 Nov 14.
Artículo en Inglés | MEDLINE | ID: mdl-36148532

RESUMEN

Organic solvent nanofiltration (OSN) is an emerging membrane separation technology, which urgently requires robust, easily processed, OSN membranes possessing high permeance and small solutes-selectivity to facilitate enhanced industrial uptake. Herein, we describe the use of two 2,2'-biphenol (BIPOL) derivatives to fabricate hyper-crosslinked, microporous polymer nanofilms through IP. Ultra-thin, defect-free polyesteramide/polyester nanofilms (≈5 nm) could be obtained readily due to the relatively large molecular size and ionized nature of the BIPOL monomers retarding the rate of the IP. The enhanced microporosity arises from the hyper-crosslinked network structure and monomer rigidity. Specifically, the amino-BIPOL/PAN membrane exhibits extraordinary permselectivity performances with molecular weight cut-off as low as 233 Da and MeOH permeance of ≈13 LMH/bar. Precise separation of small dye mixtures with similar M.W. based on both their charge and molecular size are achieved.

9.
Nanotechnology ; 33(10)2021 Dec 13.
Artículo en Inglés | MEDLINE | ID: mdl-34818634

RESUMEN

The monolayer MoS2based photodetectors have been widely investigated, which show limited photoelectric performances due to its low light absorption and uncontrollable adsorbates. In this paper, we present a MoS2-based hybrid nanoscrolls device, in which one-dimensional nanoscrollsof MoS2is hybridized with carbon quantum dots (CQDs). This device architecture effectively enhanced the photodetection performance. The photoresponsivity and detectivity values of MoS2/CQDs-NS photodetectors are respectively 1793 A W-1and 5.97 × 1012Jones, which are 830-fold and 268-fold higher than those of pristine MoS2under 300 nm illumination atVds = 5 V. This research indicates a significant progress in fabricating high-performance MoS2photodetectors.

10.
Nano Lett ; 20(1): 201-207, 2020 01 08.
Artículo en Inglés | MEDLINE | ID: mdl-31855438

RESUMEN

Recent discovery of piezoelectricity that existed in two-dimensional (2D) layered materials represents a key milestone for flexible electronics and miniaturized and wearable devices. However, so far the reported piezoelectricity in these 2D layered materials is too weak to be used for any practical applications. In this work, we discovered that grain boundaries (GBs) in monolayer MoS2 can significantly enhance its piezoelectric property. The output power of piezoelectric devices made of the butterfly-shaped monolayer MoS2 was improved about 50% by the GB-induced piezoelectric effect. The enhanced piezoelectricity is attributed to the additional piezoelectric effect induced by the existence of deformable GBs which can promote polarization and generates spontaneous polarization with different piezoelectric coefficients along various directions. We further made a flexible piezoelectric device based on the 2D MoS2 with the GBs and demonstrated its potential application in self-powered precision sensors for in situ detecting pressure changes in human blood for health monitoring.


Asunto(s)
Disulfuros/química , Suministros de Energía Eléctrica , Molibdeno/química , Dispositivos Electrónicos Vestibles , Humanos
11.
Nanotechnology ; 31(11): 115204, 2020 Mar 13.
Artículo en Inglés | MEDLINE | ID: mdl-31770747

RESUMEN

Multilayer Te nanosheets have attracted increasing attention due to their high-performance electronic transport properties and good air-stability. Theoretical simulation suggests that the electronic properties of multilayer Te nanosheets could be effectively modulated by contact engineering, but most studies have reported p-type multilayer Te devices. Here, for the first time, we report on high performance ambipolar multilayer Te filed-effect-transistors (FETs) with low work function scandium (Sc, 3.58 eV), demonstrating high mobilities of 489 and 648 cm2V-1s-1 for electron and hole transport, respectively. Multilayer Te FETs with large work function metals, such as chromium (Cr, 4.5 eV), show a typical p-type transport behavior. The band structure of multilayer Te with a small bandgap and low work function Sc result in a small contact resistance (R c) for both of electron and hole transport, which leads to the ambipolar behavior of multilayer Te nanosheets. The ambipolar behavior of multilayer Te FETs indicates that contact engineering is a valid tool to tune the electrical properties of multilayer Te and raises the possibility of designing digital circuits based on multilayer Te.

12.
Nanotechnology ; 30(24): 245706, 2019 Jun 14.
Artículo en Inglés | MEDLINE | ID: mdl-30840943

RESUMEN

Two dimensional (2D) hexagonal boron nitride (h-BN) has attracted extensive attention due to its high thermal and chemical stability, excellent dielectric characteristic, and unique optical properties. However, the chemical vapor deposition synthesis of 2D h-BN is not fully explored, such as morphology regulation and size control. Here we demonstrate the growth of 2D h-BN single domains on Cu/Ni alloy via atmospheric chemical vapor deposition (APCVD). We discover that the shape of the as-grown h-BN single domains can be controlled from triangles, hexagons, to circles by adjusting the Ni content of the Cu/Ni substrates. Moreover, we find out that increasing the nickel content can suppress the nucleation density while the average domain size is accordingly improved. The grown single-crystalline h-BN demonstrates ultralow dark current about 0.9 pA and outstanding ultraviolet response with the responsivity up to 5.45 mAW-1. The response time are 376 and 198 ms. Our work sheds light on the controllable synthesis of 2D h-BN and promotes its applications in high ultraviolet detection.

13.
Mikrochim Acta ; 186(8): 512, 2019 07 06.
Artículo en Inglés | MEDLINE | ID: mdl-31280366

RESUMEN

A method is described for combined magnetic solid phase microextraction and electrochemiluminescent (ECL) detection of the antibiotic tetracycline. A nanocomposite of type Fe3O4@SiO2@ZnO was used as the sorbent. Tetracycline has a strong affinity for Zn(II) ion and therefore is well extracted by this sorbent. The loaded sorbent can be magnetically removed. The extraction efficiency at a 1.0 µM tetracycline concentration is around 88%. Detection is based on the use of carbon nanodots that were prepared form urea and ethylenediaminetetraacetic acid as raw materials. The electrochemical probe Ru(bpy)32+ was added to generate double ECL when scanning the potential between -3.5 and + 2 V. The two ECL signals decreased with the increase of tetracycline concentration. Under optimized experimental conditions, the ratio of the two signals is linearly related to the logarithm of the tetracycline concentration in the range from 1.0 nM to 0.1 mM, with a 0.47 nM detection limit. The method was successfully applied to the determination of tetracycline in spiked milk. It exhibited good sensitivity, selectivity and accuracy due to ratiometric read-out and prior preconcentration of analyte. Graphical abstract Tetracycline (TC) has a strong affinity for Zn(II) ion and is well extracted by the Fe3O4@SiO2@ZnO nanocomposite. Ru(bpy)32+ can generate double electrochemiluminescence signals based on the use of carbon nanodots (C-dots) as coreactant. The two signals decrease with the increase of tetracycline concentration. [Ru(bpy)32+]* stands for excited state Ru(bpy)22+.


Asunto(s)
Antibacterianos/análisis , Nanopartículas de Magnetita/química , Nanocompuestos/química , Compuestos Organometálicos/química , Dióxido de Silicio/química , Tetraciclina/análisis , Óxido de Zinc/química , Animales , Antibacterianos/química , Carbono/química , Técnicas Electroquímicas , Mediciones Luminiscentes , Fenómenos Magnéticos , Leche/química , Microextracción en Fase Sólida , Tetraciclina/química
14.
Phys Rev Lett ; 120(22): 227601, 2018 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-29906143

RESUMEN

Out-of-plane ferroelectricity with a high transition temperature in ultrathin films is important for the exploration of new domain physics and scaling down of memory devices. However, depolarizing electrostatic fields and interfacial chemical bonds can destroy this long-range polar order at two-dimensional (2D) limit. Here we report the experimental discovery of the locking between out-of-plane dipoles and in-plane lattice asymmetry in atomically thin In_{2}Se_{3} crystals, a new stabilization mechanism leading to our observation of intrinsic 2D out-of-plane ferroelectricity. Through second harmonic generation spectroscopy and piezoresponse force microscopy, we found switching of out-of-plane electric polarization requires a flip of nonlinear optical polarization that corresponds to the inversion of in-plane lattice orientation. The polar order shows a very high transition temperature (∼700 K) without the assistance of extrinsic screening. This finding of intrinsic 2D ferroelectricity resulting from dipole locking opens up possibilities to explore 2D multiferroic physics and develop ultrahigh density memory devices.

15.
Nanotechnology ; 29(4): 045202, 2018 Jan 26.
Artículo en Inglés | MEDLINE | ID: mdl-29176065

RESUMEN

The hybrid n-type 2D transition-metal dichalcogenide (TMD)/p-type oxide van der Waals (vdW) heterojunction nanosheets consist of 2D layered MoSe2 (the n-type 2D material) and MoO x (the p-type oxide) which are grown on SiO2/Si substrates for the first time via chemical vapor deposition technique, displaying the regular hexagon structures with the average length dimension of sides of ∼8 µm. Vertical MoSe2-MoO x p-n heterojunctions demonstrate obviously current-rectifying characteristic, and it can be tuned via gate voltage. What is more, the photodetector based on vertical MoSe2-MoO x heterojunctions displays optimal photoresponse behavior, generating the responsivity, detectivity, and external quantum efficiency to 3.4 A W-1, 0.85 × 108 Jones, and 1665.6%, respectively, at V ds = 5 V with the light wavelength of 254 nm under 0.29 mW cm-2. These results furnish a building block on investigating the flexible and transparent properties of vdW and further optimizing the structure of the devices for better optoelectronic and electronic performance.

16.
Nanotechnology ; 29(44): 445205, 2018 Nov 02.
Artículo en Inglés | MEDLINE | ID: mdl-30136650

RESUMEN

Two-dimensional (2D) In2Se3 with unique optical and electrical properties has great potential in next generation optoelectronics and multilevel phase-change memories. Here, for the first time, we report high-performance rigid and flexible photodetectors based on chemical vapor deposition (CVD) grown 2D In2Se3. Both rigid and flexible 2D In2Se3 photodetectors show a broadband response range from ultraviolet (254 nm) to visible light (700 nm). High photoresponsivities of 578 and 363 A · W-1 are achieved using rigid and flexible 2D In2Se3 photodetectors, respectively, under 700 nm light illumination, which are higher than those of photodetectors based on mechanically exfoliated 2D In2Se3 and physical vapor deposition grown 2D In2Se3. Furthermore, flexible 2D In2Se3 photodetectors show good mechanical durability and photoresponse stability under repeated bending tests. A high and stable photoresponse provides an opportunity for CVD-grown 2D In2Se3 applications in flexible optoelectronic and photovoltaic devices.

17.
Environ Sci Technol ; 52(17): 9684-9693, 2018 09 04.
Artículo en Inglés | MEDLINE | ID: mdl-30074383

RESUMEN

Forward osmosis (FO) has gained increasing attention in desalination, wastewater treatment, and power generation. However, biofouling remains a major obstacle for the sustainable development of the FO process. Both passive and active strategies have been developed to mitigate membrane biofouling. A comprehensive understanding of different strategies and mechanisms has fundamental significance for the antifouling membrane development. In this study, thin-film composite (TFC) FO membranes were modified with polydopamine (PDA) coating as a passive antibacterial moiety and silver nanoparticles (Ag NPs) as an active antibacterial moiety. Their anti-biofouling performances were investigated both in static and dynamic conditions. In static exposure, the PDA-coated membranes exhibited great passive anti-adhesive property, and the Ag-NP-generated membranes presented both of excellent passive anti-adhesive properties and active antibacterial performance. While in dynamic cross-flow running conditions, Ag NPs effectively mitigated the membrane water flux decline due to their inhibition of biofilm growth, the PDA coating failed because of its inability to inactivate the attached bacteria growth. Moreover, Ag NPs were stable and active on membrane surfaces after 24 h of cross-flow operation. These findings provide new insights into the performances and mechanisms of passive and active moieties in the FO process.


Asunto(s)
Incrustaciones Biológicas , Nanopartículas del Metal , Purificación del Agua , Membranas Artificiales , Ósmosis , Plata
18.
Chem Biodivers ; 15(11): e1800348, 2018 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-30168654

RESUMEN

To evaluate the potential value of Seriphidium terrae-albae (Krasch.) Poljakov essential oil as bioherbicide, its chemical composition as well as phytotoxic activity was investigated. Seventeen compounds were identified via GC/MS, representing 98.1 % of the total oil, and the most abundant constituents were α-thujone (43.18 %), ß-thujone (16.92 %), eucalyptol (17.55 %), and camphor (13.88 %). Phytotoxic assay revealed that the essential oil as well as its major constituents exhibited inhibitory activity on root and shoot growth of receiver plants in a dose-dependent manner. When the concentration reached 20 µg/mL, root length of Amaranthus retroflexus was reduced to 31.3 %, 70.6 %, 36.9 %, and 66.6 % of the control, respectively, when treated with α-thujone, eucalyptol, camphor, and the mixture of these compounds; meanwhile, root length of Poa annua was 3.0 %, 24.2 %, 0 %, and 4.4 % of the control when the same chemicals were applied. On the other hand, the essential oil showed a much stronger activity. At 1.5 µL/mL, root and shoot length of A. retroflexus and P. annua were reduced to 0.65 %, 0.5 %, and 1.53 %, 1.51 % of the control, respectively, and seed germination of A. retroflexus and P. annua was completely inhibited when the oil concentration reached 3 µg/mL and 5 µg/mL, respectively. This is the first report on the chemical composition of the essential oil of S. terrae-albae, and our results indicated that it has the potential to be further exploited as a bioherbicide.


Asunto(s)
Amaranthus/efectos de los fármacos , Herbicidas/farmacología , Monoterpenos/química , Aceites Volátiles/farmacología , Fitoquímicos/farmacología , Poa/efectos de los fármacos , Amaranthus/crecimiento & desarrollo , Monoterpenos Bicíclicos , Relación Dosis-Respuesta a Droga , Herbicidas/química , Herbicidas/aislamiento & purificación , Aceites Volátiles/química , Aceites Volátiles/aislamiento & purificación , Fitoquímicos/química , Fitoquímicos/aislamiento & purificación , Raíces de Plantas/efectos de los fármacos , Raíces de Plantas/crecimiento & desarrollo , Poa/crecimiento & desarrollo , Relación Estructura-Actividad
19.
Molecules ; 23(11)2018 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-30388777

RESUMEN

The aim of this study was to identify bioactive compounds from leaves of the invasive plant Xanthium spinosum and assess their phytotoxic activity. Activity-guided fractionation led to the isolation of 6 bioactive compounds: xanthatin (1), 1α,5α-epoxyxanthatin (2), 4-epiisoxanthanol (3), 4-epixanthanol (4), loliolide (5) and dehydrovomifoliol (6). Of them, compounds 2⁻6 were isolated from the X. spinosum for the first time. The structures of 1⁻6 were elucidated on the basis of extensive NMR studies and ESI-MS measurements as well as comparison with literature data. All of compounds were evaluated for their phytotoxic activity. Among them, compounds 1⁻4 exhibited stronger activity on 2 receiver plants compared with the other 2 compounds, with xanthatin (1) being the most potent compound, which suppressed root growth of the dicot plant Amaranthus retroflexus by 32.5%, 39.4%, 84.7% when treated xanthatin (1) at 5, 20, and 100 µg/mL, while for the monocot plant, root growth was inhibited by 14.7%, 28.0%, and 40.0%, respectively. Seedling growth was nearly completely inhibited when the concentration of xanthanolides increased to 500 µg/mL, whereas there was still some seedling growth when loliolide (5) and dehydrovomifoliol (6) were applied at the same concentration. Dehydrovomifoliol (6) did not negatively affect seedling growth of P. annua at all tested concentrations, and root length was still 42.0% of the control when the highest concentration 500 µg/mL was used. This is the first report of the phytotoxicity of 1α,5α-epoxyxanthatin (2), 4-epiisxanthanol (3) and 4-epixanthanol (4). These compounds have the potential to be utilized as natural herbicides, especially 4-epiisoxanthanol (3), which exhibited significant selective activity between the dicot and monocot plants. On the other hand, whether these bioactive substances serve as allelochemicals to facilitate the invasion success of X. spinosum needs to be further studied.


Asunto(s)
Herbicidas/química , Herbicidas/farmacología , Extractos Vegetales/química , Extractos Vegetales/farmacología , Hojas de la Planta/química , Malezas/química , Xanthium/química , Estructura Molecular , Fitoquímicos/química , Fitoquímicos/farmacología
20.
Support Care Cancer ; 25(5): 1651-1659, 2017 05.
Artículo en Inglés | MEDLINE | ID: mdl-28074289

RESUMEN

PURPOSE: The aim of this study was to evaluate the therapeutic effects of Anamorelin on patients with cancer anorexia-cachexia syndrome (CACS) based on a meta-analysis of published randomized trials. METHODS: We searched PubMed, Embase, Medline, and the Cochrane Central Register of Controlled Trials databases. Data from each selected study were evaluated individually. All continuous outcomes were calculated by the mean difference or standardized mean difference with 95% confidence interval for each study. Heterogeneity was assessed by using the Chi2 test at a significance level of P < 0.1, in addition to the I 2 statistic (I 2 > 50% indicated substantial heterogeneity). RESULT: At last, four studies were included from 284 records. In three studies, lean body mass was reported and there was a significant difference between placebo and Anamorelin groups (P < 0.00001), without significant heterogeneity (I 2 = 0%). All the four studies reported the body weight change from baseline, and there was significant difference between placebo and Anamorelin groups (P = 0.007), but with high heterogeneity (I 2 = 97%). Two studies reported Anderson Symptom Assessment Scale (ASAS) score, and Anamorelin significantly increased the total ASAS score of CACS patients (P < 0.00001), without any heterogeneity (I 2 = 0%). Three studies reported non-dominant handgrip strength, and there was no significant difference between Anamorelin and placebo groups (P = 0.16). Three studies reported insulin-like growth factor-1 level, and there was significant difference between Anamorelin and placebo groups (P = 0.02), but with high heterogeneity (I 2 = 96%). Three studies reported IGF binding protein-3 concentration. Anamorelin significantly increased such concentration compared with placebo did (P < 0.00001). However, there was still higher heterogeneity (I 2 = 59%). All the included studies reported adverse events. Compared with placebo, Anamorelin induced fewer adverse events, but there was no significant difference between the two groups (RR = 0.07, P = 0.35). CONCLUSION: In the included studies, Anamorelin had some positive effects to relieve the symptoms and improved the quality of life. However, the heterogeneity was apparent, so the clinical effects of Anamorelin should be further validated by increasing the sample size, varying the range of doses during treatment, and observing other outcomes. We are still confident for the future application of Anamorelin in phase III clinical trials.


Asunto(s)
Anorexia/tratamiento farmacológico , Caquexia/tratamiento farmacológico , Hidrazinas/uso terapéutico , Neoplasias/complicaciones , Oligopéptidos/uso terapéutico , Femenino , Humanos , Hidrazinas/administración & dosificación , Hidrazinas/farmacología , Oligopéptidos/administración & dosificación , Oligopéptidos/farmacología , Calidad de Vida , Síndrome
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