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1.
Environ Pollut ; 345: 123503, 2024 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-38331243

RESUMEN

Methyl jasmonate (MeJA), a crucial phytohormone, which plays an important role in resistance to Cadmium (Cd) stress. The cell wall (CW) of root system is the main location of Cd and plays a key role in resistance to Cd toxicity. However, the mechanism effect of MeJA on the CW composition and Cd accumulation remain unclear. In this study, the contribution of MeJA in regulating CW structure, pectin composition and Cd accumulation was investigated in Cosmos bipinnatus. Phenotypic results affirm MeJA's significant role in reducing Cd-induced toxicity in C. bipinnatus. Notably, MeJA exerts a dual impact, reducing Cd uptake in roots while increasing Cd accumulation in the CW, particularly bound to pectin. The molecular structure of pectin, mainly uronic acid (UA), correlates positively with Cd content, consistent in HC1 and cellulose, emphasizing UA as pivotal for Cd binding. Furthermore, MeJA modulates pectin methylesterase (PME) activity under Cd stress, influencing pectin's molecular structure and homogalacturonan (HG) content affecting Cd-binding capacity. Chelate-soluble pectin (CSP) within soluble pectins accumulates a substantial Cd proportion, with MeJA regulating both UA content and the minor component 3-deoxy-oct-2-ulosonic acid (Kdo) in CSP. The study delves into the intricate regulation of pectin monosaccharide composition under Cd stress, revealing insights into the CW's physical defense and Cd binding. In summary, this research provides novel insights into MeJA-specific mechanisms alleviating Cd toxicity in C. bipinnatus, shedding light on complex interactions between MeJA, and Cd accumulation in CW pectin polysaccharide.


Asunto(s)
Acetatos , Asteraceae , Cadmio , Ciclopentanos , Oxilipinas , Cadmio/metabolismo , Raíces de Plantas/metabolismo , Polisacáridos/metabolismo , Polisacáridos/farmacología , Pectinas/química , Pared Celular/metabolismo , Asteraceae/metabolismo
2.
BMC Cardiovasc Disord ; 23(1): 496, 2023 10 07.
Artículo en Inglés | MEDLINE | ID: mdl-37805479

RESUMEN

BACKGROUND: Cell division control 42 (CDC42) regulates atherosclerosis, blood lipids, and inflammation and thus affects coronary artery disease (CAD), but its utility in drug-coated balloon (DCB)-treated small-vessel CAD (SV-CAD) patients is unclear. This study intended to evaluate the change and prognostic role of CDC42 in SV-CAD patients underwent DCB. METHODS: Serum CDC42 was measured by enzyme-linked immunosorbent assay in 211 SV-CAD patients underwent DCB at baseline, day (D) 1, D3, and D7, as well as in 50 healthy controls (HCs). RESULTS: CDC42 was decreased in SV-CAD patients compared to HCs (P < 0.001), and it was negatively associated with total cholesterol (P = 0.015), low-density lipoprotein cholesterol (P = 0.003), C-reactive protein (P = 0.001), multivessel disease (P = 0.020), and American college of cardiology/American heart association type B2/C lesions (P = 0.039) in SV-CAD patients. Longitudinally, CDC42 decreased from baseline to D1 and then gradually increased to D7 (P < 0.001) in SV-CAD patients after DCB. Interestingly, high CDC42 (cut-off value = 500 pg/mL) at baseline (P = 0.047), D3 (P = 0.046), and D7 (P = 0.008) was associated with a lower accumulating target lesion failure (TLF) rate; high CDC42 at D3 (P = 0.037) and D7 (P = 0.041) was related to a lower accumulating major adverse cardiovascular event (MACE) rate in SV-CAD patients underwent DCB. Importantly, CDC42 at D7 (high vs. low) independently predicted lower accumulating TLF (hazard ratio (HR) = 0.145, P = 0.021) and MACE (HR = 0.295, P = 0.023) risks in SV-CAD patients underwent DCB. CONCLUSIONS: Circulating CDC42 level relates to milder disease conditions and independently estimates lower risks of TLF and MACE in SV-CAD patients underwent DCB, but further validation is still needed.


Asunto(s)
Enfermedad de la Arteria Coronaria , Stents Liberadores de Fármacos , Intervención Coronaria Percutánea , Humanos , Enfermedad de la Arteria Coronaria/diagnóstico por imagen , Enfermedad de la Arteria Coronaria/terapia , Enfermedad de la Arteria Coronaria/etiología , Intervención Coronaria Percutánea/efectos adversos , Resultado del Tratamiento , Colesterol
3.
Ecotoxicol Environ Saf ; 261: 115101, 2023 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-37290296

RESUMEN

Cadmium (Cd) pollution is a global problem affecting soil ecology and plant growth. Abscisic acid (ABA) acts as a growth and stress hormone, regulates cell wall synthesis, and plays an important role in plant responses to stress. There are few studies on the mechanisms behind abscisic acid alleviation of cadmium stress in Cosmos bipinnatus, especially in regards to regulation of the root cell wall. This study examined the effects of different concentrations of abscisic acid at different concentrations of cadmium stress. Through adding 5 µmol/L and 30 µmol/L cadmium, followed by spraying 10 µmol/L and 40 µmol/L ABA in a hydroponic experiment, it was found that under two concentrations of cadmium stress, low concentration of ABA improved root cell wall polysaccharide, Cd, and uronic acid content. Especially in pectin, after the application of low concentration ABA, the cadmium concentration was significantly increased by 1.5 times and 1.2 times compared with the Cd concentration under Cd5 and Cd30 treatment alone, respectively. Fourier-Transform Infrared spectroscopy (FTIR) demonstrated that cell wall functional groups such as -OH and -COOH were increased with exposure to ABA. Additionally, the exogenous ABA also increased expression of three kinds of antioxidant enzymes and plant antioxidants. The results of this study suggest that ABA could reduce Cd stress by increasing Cd accumulation, promoting Cd adsorption on the root cell wall, and activating protective mechanisms. This result could help promote application of C. bipinnatus for phytostabilization of cadmium-contaminated soil.


Asunto(s)
Asteraceae , Cadmio , Cadmio/metabolismo , Antioxidantes/farmacología , Antioxidantes/metabolismo , Ácido Abscísico/farmacología , Ácido Abscísico/metabolismo , Adsorción , Asteraceae/metabolismo , Pared Celular/metabolismo , Raíces de Plantas/metabolismo
4.
New Phytol ; 239(1): 75-86, 2023 07.
Artículo en Inglés | MEDLINE | ID: mdl-36978285

RESUMEN

Trait-based approaches provide a useful framework to predict ecosystem functions under intensifying global change. However, our current understanding of trait-functioning relationships mainly relies on aboveground traits. Belowground traits (e.g. absorptive root traits) are rarely studied although these traits are related to important plant functions. We analyzed four pairs of analogous leaf and absorptive root traits of woody plants in a temperate forest and examined how these traits are coordinated at the community-level, and to what extent the trait covariation depends on local-scale environmental conditions. We then quantified the contributions of leaf and absorptive root traits and the environmental conditions in determining two important forest ecosystem functions, aboveground carbon storage, and woody biomass productivity. The results showed that both morphological trait pairs and chemical trait pairs exhibited positive correlations at the community level. Absorptive root traits show a strong response to environmental conditions compared to leaf traits. We also found that absorptive root traits were better predictors of the two forest ecosystem functions than leaf traits and environmental conditions. Our study confirms the important role of belowground traits in modulating ecosystem functions and deepens our understanding of belowground responses to changing environmental conditions.


Asunto(s)
Ecosistema , Bosques , Biomasa , Plantas/anatomía & histología , Madera
5.
Chemosphere ; 315: 137677, 2023 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-36608889

RESUMEN

As one of the major pollutants in the environment, chromium (Cr), a heavy metal, poses a serious threat to urban green spaces and human life and health. Cosmos bipinnatus is considered a potential accumulator of Cr, and the differences in cellular Cr distribution and compartmentalization may uncover the mechanisms involved in its tolerance to Cr. To elucidate the effects of Cr stress on C. bipinnatus and determine the mechanism of Cr tolerance in C. bipinnatus, we investigated the physiological indicators, subcellular distribution and chemical forms, cell wall fractions and their Cr contents, uronic acid content in the cell wall fractions, and Fourier transform infrared spectroscopy (FTIR) of the cell wall. The results showed that the antioxidant enzyme activities in C. bipinnatus under Cr stress and most of the Cr were fixed in the cell wall. Notably, changes in the content of pectin fractions in the cell wall affected the accumulation of Cr in the cell wall of C. bipinnatus and the stability of negatively charged groups. In addition, the carboxyl and hydroxyl groups played a role in fixing metal in various parts of the C. bipinnatus cell wall.


Asunto(s)
Asteraceae , Cromo , Humanos , Cromo/toxicidad , Antioxidantes , Pared Celular
6.
Ecol Evol ; 12(7): e9110, 2022 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-35845366

RESUMEN

Estimating forest above-ground biomass (AGB) productivity constitutes one of the most fundamental topics in forest ecological research. Based on a 30-ha permanent field plot in Northeastern China, we modeled AGB productivity as output, and topography, species diversity, stand structure, and a stand density variable as input across a series of area scales using the Random Forest (RF) algorithm. As the grain size increased from 10 to 200 m, we found that the relative importance of explanatory variables that drove the variation of biomass productivity varied a lot, and the model accuracy was gradually improved. The minimum sampling area for biomass productivity modeling in this region was 140 × 140 m. Our study shows that the relationship of topography, species diversity, stand structure, and stand density variables with biomass productivity modeled using the RF algorithm changes when moving from scales typical of forest surveys (10 m) to larger scales (200 m) within a controlled methodology. These results should be of considerable interest to scientists concerned with forest assessment.

7.
Adv Mater ; 34(48): e2108473, 2022 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-34957614

RESUMEN

Over the past two decades, research on 2D materials has received much interest. Graphene is the most promising candidate regarding high-frequency applications thus far due to is high carrier mobility. Here, the research about the employment of graphene in micro- and millimeter-wave circuits is reviewed. The review starts with the different methodologies to grow and transfer graphene, before discussing the way graphene-based field-effect-transistors (GFETs) and diodes are built. A review on different approaches for realizing these devices is provided before discussing the employment of both GFETs and graphene diodes in different micro- and millimeter-wave circuits, showing the possibilities but also the limitations of this 2D material for high-frequency applications.

8.
Ecol Evol ; 11(16): 11362-11372, 2021 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-34429925

RESUMEN

ß-Diversity, which describes the extent of change in species composition in a given region, has become a core issue in ecology in recent years. However, it is hard to understand the underlying mechanisms of ß-diversity by using indices that yield identical values under species replacement and nestedness pattern. Partitioning ß-diversity into turnover (caused by species replacement among plots) and nestedness components (caused by species loss or gain among plots) may provide improved understanding of the variation in species composition. Here, we collected presence-absence data of 456 one-tenth ha circular plots in the temperate forests of Northeastern China spanning a latitudinal range of 12° (41-53°N). We decomposed ß-diversity to assess the relative contribution of the turnover and nestedness components across latitudinal gradients. We used regression analysis to assess the relationship between spatial distance and ß-diversity. We applied variation partitioning to evaluate the importance of the measured environmental and spatial variables in explaining ß-diversity. We used the Tukey honest significant difference test to test the differences of ß-diversity along latitudinal gradients. Pearson correlations (r) and significance (p-value) were computed using the Mantel tests to verify the relationship between distance and ß-diversity. The ANOVA test was used to verify whether the variation of ß-diversity explained by the environment and distance was significant. Our results showed that (1) ß-diversity and the turnover component were higher at low latitudes (zones A and B) than at high latitudes (zones C and D), while there was no relationship between the nestedness component and latitude. (2) The turnover component was dominant. (3) The spatial distance explained more variation of ß-diversity than the measured environmental factors. Therefore, we conclude that ß-diversity is mainly a product of species turnover in our temperate forests, suggesting that different localities harbor different species. We find that decomposing ß-diversity into the turnover and nestedness components is a useful approach to explore the variation of community composition and their causes.

9.
J Interv Cardiol ; 2021: 7099044, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34381321

RESUMEN

OBJECTIVE: The previous meta-analysis has assessed that distal transradial access (dTRA) in anatomical snuffbox is safe and effective for coronary angiography and intervention and can reduce radial artery occlusion. However, since the publication of the previous meta-analysis, several observational studies have been added, so we performed an updated meta-analysis to include more eligible studies to compare distal transradial access in anatomical snuffbox with conventional transradial access (cTRA). METHOD: Pubmed, Embase, and Cochrane Library databases were searched for relevant studies from the literature published until 5 January 2021 to evaluate catheterization/puncture failure, hematoma, radial artery spasm, radial artery occlusion (RAO), access time, fluoroscopy time, radiation dose area product, total procedure time, and hemostatic device removal time. The pooled odds ratio (OR), weighted mean difference (WMD), and standardized mean difference (SMD) with 95% confidence interval (95% CI) were calculated for dichotomous and continuous variables, respectively. RESULTS: A total of 9,054 patients from 14 studies were included in the meta-analysis, and we found no significant difference in catheterization/puncture failure (OR = 1.94, 95CI [0.97, 3.86], P=0.06), hematoma (OR = 0.97, 95CI [0.55, 1.73], P=0.926), radial artery spasm (OR = 0.76, 95CI [0.43, 1.36], P=0.354), total procedure time (SMD = 0.23, 95CI [-0.21, 0.68], P=0.308), or radiation dose area product (WMD = 216.88 Gy/cm2, 95CI [-126.24, 560.00], P=0.215), but dTRA had a lower incidence of RAO (OR = 0.39, 95CI [0.23, 0.66], P < 0.001), shorter hemostatic device removal time (WMD = -66.62 min, 95CI [-76.68, -56.56], P < 0.001), longer access time (SMD = 0.32, 95CI [0.08, 0.56], P=0.008), and longer fluoroscopy time (SMD = 0.16, 95CI [-0.00, 0.33], P=0.05) than cTRA. CONCLUSION: Compared with the cTRA, the dTRA has a lower incidence of radial artery occlusion and shorter hemostatic device removal time, which is worthy of further evaluation in clinical practice.


Asunto(s)
Intervención Coronaria Percutánea , Angiografía Coronaria/efectos adversos , Humanos , Intervención Coronaria Percutánea/efectos adversos , Estudios Prospectivos , Arteria Radial , Estudios Retrospectivos
10.
Ecol Evol ; 10(15): 8225-8234, 2020 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-32788974

RESUMEN

The relationship between biodiversity and productivity has stimulated an increasing body of research over the past decades, and this topic still occupies a central place in ecology. While most studies have focused on biomass production in quadrats or plots, few have investigated the scale-dependent relationship from an individual plant perspective. We present an analysis of the effects of biodiversity (species diversity and functional diversity) on individual tree growth with a data set of 16,060 growth records from a 30-ha temperate forest plot using spatially explicit individual tree-based methods. A significant relationship between species diversity and tree growth was found at the individual tree level in our study. The magnitude and direction of biodiversity effects varies with the spatial scale. We found positive effects of species diversity on tree growth at scales exceeding 9 m. Individual tree growth rates increased when there was a greater diversity of species in the neighborhood of the focal tree, which provides evidence of a niche complementarity effect. At small scales (3-5 m), species diversity had negative effects on tree growth, suggesting that competition is more prevalent than complementarity or facilitation in these close neighborhoods. The results also revealed many confounding factors which influence tree growth, such as elevation and available sun light. We conclude that the use of individual tree-based methods may lead to a better understanding of the biodiversity-productivity relationship in forest communities.

11.
Heart Lung Circ ; 29(12): 1856-1864, 2020 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-32611501

RESUMEN

BACKGROUND: Sex differences in the long-term prognosis of symptomatic hypertrophic obstructive cardiomyopathy (HOCM) patients undergoing alcohol septal ablation (ASA) remain unclear, especially in the Chinese Han population. METHOD: This cohort study included 320 HOCM Chinese Han patients who underwent ASA because of symptomatic left ventricular outflow tract (LVOT) obstruction. Patients were grouped according to sex: females (mean±standard deviation age [SD] 50.7±6.8 years) and males (mean±SD age 52.6±7.3 years). Individuals were followed over the long term. RESULTS: Pre-procedure, women had more symptoms (New York Heart Association [NYHA] class III-IV 67.3% vs 56.3%, p=0.03), more atrial fibrillation (23.5% vs 14.6%, p=0.047) than men. Transient complete atrioventricular block after ASA was more common in woman than in men (34.0 vs 23.4%; p=0.048). Residual LVOT gradient, post-procedural residual left ventricular wall thickness, NYHA functional class, and adverse arrhythmic events were comparable between the two groups. The 10-year survival rate (77% vs 89%, p=0.037) and the annual adverse arrhythmic event rate (1.3% vs 0.4%, p<0.01) following ASA were significantly worse in women compared with men. Kaplan-Meier analysis showed a significantly lower survival in women compared with men (p=0.023). In multivariable modelling, female sex remained independently associated with higher all-cause mortality (hazard ratio, 1.12; 95% confidence interval, 1.08-1.27; p=0.03) when adjusted for age, NYHA class III-IV symptoms, and other cardiovascular comorbidities. CONCLUSIONS: Female patients with HOCM undergoing ASA tended to have more severe symptoms and adverse arrhythmic events. The 10-year survival rate after ASA was significantly worse in women compared with men with HOCM. Sex may need to be considered as an important factor in the clinical management of patients with symptomatic HOCM.


Asunto(s)
Técnicas de Ablación/métodos , Cardiomiopatía Hipertrófica/etnología , Etanol/farmacología , Etnicidad , Tabiques Cardíacos/efectos de los fármacos , Cardiomiopatía Hipertrófica/diagnóstico , Cardiomiopatía Hipertrófica/terapia , China/epidemiología , Femenino , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Factores de Tiempo , Resultado del Tratamiento
12.
Catheter Cardiovasc Interv ; 93(S1): 825-831, 2019 02 15.
Artículo en Inglés | MEDLINE | ID: mdl-30724035

RESUMEN

OBJECTIVES: To assess the efficacy and safety of bivalirudin during percutaneous coronary intervention (PCI) for chronic total occlusion (CTO) in high-bleeding-risk elderly patients. BACKGROUND: Bivalirudin reduces PCI-related bleeding; however, its efficacy and safety in patients with CTO, especially elderly patients with a high bleeding risk, remain unclear. METHODS: This single-center prospective randomized controlled trial assigned 123 high-bleeding-risk elderly patients with CTO to either the unfractionated heparin (UFH) group (n = 55) or the bivalirudin group (n = 68). The primary efficacy endpoint was the incidence of major adverse cardiac events (MACEs) during hospitalization and at the 6-month follow-up. The safety endpoint was bleeding or procedure (access)-related complications after PCI. RESULTS: MACE incidence was 17.6% and 20.0% in the bivalirudin and UFH groups, respectively (P = 0.82). Bleeding Academic Research Consortium (BARC) type 1-2 bleeding events during hospitalization were comparable between the groups (UFH: 10.9% vs. bivalirudin: 8.8%, P = 0.77). No BARC type 3-5 bleeding events or severe procedure (access)-related complications (subcutaneous hematoma >5 cm) occurred in either group. At the 6-month follow-up, MACE incidence was comparable between the groups (UFH: 3.6% vs. bivalirudin: 1.5%, P = 0.59). The Kaplan-Meier analysis revealed that MACE-free survival rates were comparable between the groups (P = 0.43). One case of BARC type 3-5 bleeding (fatal intracranial hemorrhage) was observed in the UFH group at the 6-month follow-up. CONCLUSIONS: Bivalirudin and UFH showed comparable efficacy and safety in elderly patients with a high bleeding risk, undergoing PCI for CTO lesions.


Asunto(s)
Anticoagulantes/administración & dosificación , Antitrombinas/administración & dosificación , Oclusión Coronaria/terapia , Hemorragia/epidemiología , Heparina/administración & dosificación , Hirudinas/administración & dosificación , Fragmentos de Péptidos/administración & dosificación , Intervención Coronaria Percutánea/efectos adversos , Factores de Edad , Anciano , Anticoagulantes/efectos adversos , Antitrombinas/efectos adversos , China/epidemiología , Enfermedad Crónica , Oclusión Coronaria/diagnóstico por imagen , Oclusión Coronaria/mortalidad , Trombosis Coronaria/epidemiología , Femenino , Hemorragia/inducido químicamente , Hemorragia/mortalidad , Heparina/efectos adversos , Hirudinas/efectos adversos , Humanos , Masculino , Persona de Mediana Edad , Infarto del Miocardio/epidemiología , Fragmentos de Péptidos/efectos adversos , Intervención Coronaria Percutánea/mortalidad , Supervivencia sin Progresión , Estudios Prospectivos , Proteínas Recombinantes/administración & dosificación , Proteínas Recombinantes/efectos adversos , Medición de Riesgo , Factores de Riesgo , Factores de Tiempo
13.
Eur J Nucl Med Mol Imaging ; 45(12): 2181-2189, 2018 11.
Artículo en Inglés | MEDLINE | ID: mdl-30171271

RESUMEN

OBJECTIVES: The aim of this study was to evaluate the 18F-sodium fluoride (18F-NaF) coronary uptake compared to coronary intravascular ultrasound (IVUS) in patients with symptomatic coronary artery disease. BACKGROUND: 18F-NaF PET enables the assessment of vascular osteogenesis by interaction with surface hydroxyapatite, while IVUS enables both identification and quantification of intra-plaque components. METHODS: Forty-four patients with symptomatic coronary artery disease were included in this prospective controlled trial, 32 of them (30 patients with unstable angina and 2 patients with stable angina), representing the final study cohort, got additional IVUS. All patients underwent cardiac 18F-NaF PET/CT and IVUS within 2 days. 18F-NaF maximum tissue-to-blood ratios (TBRmax) were calculated for 69 coronary plaques and correlated with IVUS plaque classification. RESULTS: Significantly increased 18F-NaF uptake ratios were observed in fibrocalcific lesions (meanTBRmax = 1.42 ± 0.28), thin-cap atheroma with spotty calcifications (meanTBRmax = 1.32 ± 0.23), and thick-cap mixed atheroma (meanTBRmax = 1.28 ± 0.38), while fibrotic plaques showed no increased uptake (meanTBRmax = 0.96 ± 0.18). The 18F-NaF uptake ratio was consistently higher in atherosclerotic lesions with severe calcification (meanTBRmax = 1.34 ± 0.22). The regional 18F-NaF uptake was most likely localized in the border region of intensive calcification. Coronary lesions with positive 18F-NaF uptake showed some increased high-risk anatomical features on IVUS in comparison to 18F-NaF negative plaques. It included a significant severe plaque burden (70.1 ± 13.8 vs. 61.0 ± 13.8, p = 0.01) and positive remodeling index (1.03 ± 0.08 vs. 0.99 ± 0.07, p = 0.05), as well as a higher percentage of necrotic tissue (37.6 ± 13.3 vs. 29.3 ± 15.7, p = 0.02) in positive 18F-NaF lesions. CONCLUSIONS: 18F-NaF coronary uptake may provide a molecular insight for the characterization of coronary atherosclerotic lesions. Specific regional uptake is needed to be determined by histology.


Asunto(s)
Enfermedad de la Arteria Coronaria/diagnóstico por imagen , Placa Aterosclerótica/diagnóstico por imagen , Tomografía Computarizada por Tomografía de Emisión de Positrones , Fluoruro de Sodio , Ultrasonografía Intervencional , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad
14.
Ecol Evol ; 7(23): 10116-10123, 2017 12.
Artículo en Inglés | MEDLINE | ID: mdl-29238541

RESUMEN

This study aims to establish a relationship between the sampling scale and tree species beta diversity temperate forests and to identify the underlying causes of beta diversity at different sampling scales. The data were obtained from three large observational study areas in the Changbai mountain region in northeastern China. All trees with a dbh ≥1 cm were stem-mapped and measured. The beta diversity was calculated for four different grain sizes, and the associated variances were partitioned into components explained by environmental and spatial variables to determine the contributions of environmental filtering and dispersal limitation to beta diversity. The results showed that both beta diversity and the causes of beta diversity were dependent on the sampling scale. Beta diversity decreased with increasing scales. The best-explained beta diversity variation was up to about 60% which was discovered in the secondary conifer and broad-leaved mixed forest (CBF) study area at the 40 × 40 m scale. The variation partitioning result indicated that environmental filtering showed greater effects at bigger grain sizes, while dispersal limitation was found to be more important at smaller grain sizes. What is more, the result showed an increasing explanatory ability of environmental effects with increasing sampling grains but no clearly trend of spatial effects. The study emphasized that the underlying causes of beta diversity variation may be quite different within the same region depending on varying sampling scales. Therefore, scale effects should be taken into account in future studies on beta diversity, which is critical in identifying different relative importance of spatial and environmental drivers on species composition variation.

15.
BMC Ecol ; 17(1): 33, 2017 10 30.
Artículo en Inglés | MEDLINE | ID: mdl-29084533

RESUMEN

BACKGROUND: One of the core issues of forest community ecology is the exploration of how ecological processes affect community structure. The relative importance of different processes is still under debate. This study addresses four questions: (1) how is the taxonomic structure of a forest community affected by spatial scale? (2) does the taxonomic structure reveal effects of local processes such as environmental filtering, dispersal limitation or interspecific competition at a local scale? (3) does the effect of local processes on the taxonomic structure vary with the spatial scale? (4) does the analysis based on taxonomic structures provide similar insights when compared with the use of phylogenetic information? Based on the data collected in two large forest observational field studies, the taxonomic structures of the plant communities were analyzed at different sampling scales using taxonomic ratios (number of genera/number of species, number of families/number of species), and the relationship between the number of higher taxa and the number of species. Two random null models were used and the "standardized effect size" (SES) of taxonomic ratios was calculated, to assess possible differences between the observed and simulated taxonomic structures, which may be caused by specific ecological processes. We further applied a phylogeny-based method to compare results with those of the taxonomic approach. RESULTS: As expected, the taxonomic ratios decline with increasing grain size. The quantitative relationship between genera/families and species, described by a linearized power function, showed a good fit. With the exception of the family-species relationship in the Jiaohe study area, the exponents of the genus/family-species relationships did not show any scale dependent effects. The taxonomic ratios of the observed communities had significantly lower values than those of the simulated random community under the test of two null models at almost all scales. Null Model 2 which considered the spatial dispersion of species generated a taxonomic structure which proved to be more consistent with that in the observed community. As sampling sizes increased from 20 m × 20 m to 50 m × 50 m, the magnitudes of SESs of taxonomic ratios increased. Based on the phylogenetic analysis, we found that the Jiaohe plot was phylogenetically clustered at almost all scales. We detected significant phylogenetically overdispersion at the 20 m × 20 m and 30 m × 30 m scales in the Liangshui plot. CONCLUSIONS: The results suggest that the effect of abiotic filtering is greater than the effects of interspecific competition in shaping the local community at almost all scales. Local processes influence the taxonomic structures, but their combined effects vary with the spatial scale. The taxonomic approach provides similar insights as the phylogenetic approach, especially when we applied a more conservative null model. Analysing taxonomic structure may be a useful tool for communities where well-resolved phylogenetic data are not available.


Asunto(s)
Ecosistema , Bosques , Plantas/clasificación , China , Filogenia , Plantas/genética
16.
Int J Pharm ; 516(1-2): 32-38, 2017 Jan 10.
Artículo en Inglés | MEDLINE | ID: mdl-27825865

RESUMEN

The novel antipsychotic isoperidone, a prodrug of paliperidone, was designed to improve liposolubility for the development of poly(D,L-lactide-co-glycolide) (PLGA)-based microspheres to achieve near zero-order release behaviour in vivo. Microspheres with a smooth surface were obtained using the oil-in-water emulsion solvent evaporation method and yielded a high encapsulation efficiency of 92%. Pharmacokinetic studies in beagle dogs showed a one-week plateau phase followed by a two-week quasi-zero-order release with no burst release. The in vitro release method with a good in vitro-in vivo correlation was also established. Pharmacodynamic evaluation was performed using the MK-801-induced schizophrenic behavioural mouse model, and the sustained suppressive effect lasted two weeks. The pharmacokinetic-pharmacodynamic (PK-PD) relationship of isoperidone microspheres was compared to that of oral administration of free drug. The results revealed a strong correlation between the plasma drug level and the antipsychotic effect. A stable drug plasma concentration was detected in mice both intraday and interday from 8 to 22 d after a single injection of isoperidone microspheres, and a sustained suppressive effect on the schizophrenic model was also observed. In comparison, the mouse group receiving oral daily administration exhibited more dose-dependent effects, and the pharmacological effect diminished rapidly in conjunction with a reduction of the plasma drug levels 8h after the last administration of isoperidone on day 3. The above results confirm the superiority of long-acting release over oral administration and indicate a valuable alternative for the clinical treatment of schizophrenia.


Asunto(s)
Antipsicóticos/administración & dosificación , Portadores de Fármacos/química , Ácido Láctico/química , Palmitato de Paliperidona/análogos & derivados , Ácido Poliglicólico/química , Administración Oral , Animales , Antipsicóticos/farmacocinética , Antipsicóticos/farmacología , Química Farmacéutica/métodos , Preparaciones de Acción Retardada , Modelos Animales de Enfermedad , Maleato de Dizocilpina/toxicidad , Perros , Relación Dosis-Respuesta a Droga , Composición de Medicamentos , Liberación de Fármacos , Masculino , Ratones , Microesferas , Palmitato de Paliperidona/administración & dosificación , Palmitato de Paliperidona/farmacocinética , Palmitato de Paliperidona/farmacología , Copolímero de Ácido Poliláctico-Ácido Poliglicólico , Profármacos , Esquizofrenia/tratamiento farmacológico , Solubilidad , Factores de Tiempo
17.
Eur J Pharm Sci ; 96: 530-541, 2017 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-27789373

RESUMEN

development, single-factor experiments were employed to evaluate the effect of adding different matrix, enhancers, 5-HMT, ethanol and glycerol on drug skin development, single-factor experiments were employed to evaluate the effect of adding different matrix, enhancers, 5-HMT, ethanol and glycerol on drug skin permeation. Finally, Carbopol 940 was selected as the gel matrix with N-methyl pyrrolidone (NMP) chosen as the enhancer. The relationship between time and the steady accumulative percutaneous amount (Q, µgcm-2) of optimized 5-HMT hydrogels was Q4-12h=1290.8t1/2-1227.7. The absolute bioavailability of 5-HMT hydrogels was 20.7% showed in pharmacokinetic study. No skin irritation was observed in 5-HMT hydrogels skin irritation study. In the pharmacodynamic study, the overactive bladder model was induced by 150µg/kg of pilocarpine in rats. The significant effects of 5-HMT hydrogels on the inhibition of urine output on rat model were last to 12h. The optimized 5-HMT hydrogels displayed prolonged pharmacological responses. 5-HMT hydrogels effectively avoided the metabolism difference of enzyme in bodies compared with tolterodine tablets, provided one single active compound in plasma to reduce the variability of having two active compounds. To further elucidate the transdermal mechanism, fourier transform infrared (FTIR) spectroscopy, differential scanning calorimeter (DSC) and activation energy measurements were used to study the transdermal routes and changes of stratum corneum during drug release.


Asunto(s)
Compuestos de Bencidrilo/administración & dosificación , Compuestos de Bencidrilo/farmacocinética , Cresoles/administración & dosificación , Cresoles/farmacocinética , Diseño de Fármacos , Hidrogeles/administración & dosificación , Hidrogeles/farmacocinética , Absorción Cutánea/efectos de los fármacos , Administración Cutánea , Animales , Compuestos de Bencidrilo/síntesis química , Cresoles/síntesis química , Femenino , Hidrogeles/síntesis química , Masculino , Ratones , Técnicas de Cultivo de Órganos , Conejos , Ratas , Ratas Sprague-Dawley , Absorción Cutánea/fisiología
18.
Sci Rep ; 6: 35022, 2016 10 11.
Artículo en Inglés | MEDLINE | ID: mdl-27725739

RESUMEN

This study evaluates stoichiometry patterns in the androdioecious Acer tegmentosum, a species characterized by a rare reproductive system where males and hermaphrodites coexist. Altogether 31 hermaphrodites and 29 male plants were harvested and samples of leaves, current-year shoots, branches and coarse roots were analyzed to explore gender differences in biomass, C, N and P concentrations of these four components. The nitrogen to phosphorus relationship of each component was examined using SMA estimates. Males had significantly greater amounts of leaf and coarse root dry matter content than hermaphrodites. C, N and P stoichiometry differed significantly between genders, especially in the newly emerging vegetative components (leaves and shoots). Males had higher C/N and C/P ratios in current-year shoots and lower C/P ratios in leaves and branches. Hermaphrodites had higher N/P ratios in the leaves and branches. Males had higher rates of increase in leaf P content than hermaphrodites. This study suggests that stoichiometry patterns may be significantly affected by gender.


Asunto(s)
Acer/fisiología , Hojas de la Planta/química , Brotes de la Planta/química , Acer/química , Biomasa , Carbono/análisis , Nitrógeno/análisis , Fósforo/análisis , Reproducción
19.
Drug Deliv ; 23(4): 1194-203, 2016 May.
Artículo en Inglés | MEDLINE | ID: mdl-26635185

RESUMEN

The present systematic study focused to investigate the oleic acid derivative of branched polyethylenimine (bPEI-OA)-functionalized proliposomes for improving the oral delivery of extract of Ginkgo biloba (GbE). The GbE proliposomes were prepared by a spray drying method at varying ratios of egg yolk phosphatidylcholine and cholesterol, and the optimized formulation was tailored with bPEI-OA to obtain bPEI-OA-functionalized proliposomes. The formulations were characterized for particle size, zeta potential, and entrapment efficiency. The release of GbE from proliposomes exhibited a sustained release. And the release rate was regulated by changing the amount of bPEI-OA on the proliposomes. The physical state characterization studies showed some interactions between GbE and other materials, such as hydrogen bonds and van der Waals forces during the process of preparation of proliposomes. The in situ single-pass perfusion and oral bioavailability studies were performed in rats. The significant increase in absorption constant (Ka) and apparent permeability coefficient (Papp) from bPEI-OA-functionalized proliposomes indicated the importance of positive charge for effective uptake across the gastrointestinal tract. The oral bioavailability of bPEI-OA-functionalized proliposomes was remarkable enhanced in comparison with control and conventional proliposomes. The bPEI-OA-functionalized proliposomes showed great potential of improving oral absorption of GbE as a suitable carrier.


Asunto(s)
Colesterol/química , Ginkgo biloba/metabolismo , Ácido Oléico/química , Fosfatidilcolinas/química , Polietileneimina/química , Animales , Disponibilidad Biológica , Química Farmacéutica , Colesterol/metabolismo , Portadores de Fármacos , Ginkgo biloba/química , Liposomas , Tamaño de la Partícula , Permeabilidad , Fosfatidilcolinas/metabolismo , Ratas
20.
Int J Cardiol ; 146(3): 341-6, 2011 Feb 03.
Artículo en Inglés | MEDLINE | ID: mdl-19709765

RESUMEN

BACKGROUND: Acute coronary syndrome (ACS) is an independent risk factor for late stent thrombosis which might be related to the impaired vascular healing after drug-eluting stent (DES) due to the disruption of plaques and thrombus formation. Therefore, we investigated the vascular response after various DES implantations between ACS and stable angina pectoris (SAP) using optical coherence tomography (OCT). METHODS: Ninety-one patients [49 ACS: 20 sirolimus-eluting (SES), 12 paclitaxel-eluting (PES) and 17 zotarolimus eluting stent (ZES) and 42 SAP: 15 SES, 12 PES and 15 ZES] underwent OCT at 9 months after stent implantation. Neointimal coverage and malapposition were evaluated in 21,939 struts in 2269-mm stented segments. RESULTS: In the ACS group, the incidence of uncovered and malapposed struts was significantly higher (8.9 ± 13.7 vs 2.9 ± 6.2%, p = 0.01 and 2.2 ± 5.6 vs 0.5 ± 2.0%, p = 0.02). Among the three DESs tested, SES showed a significantly higher rate of uncovered struts in the ACS group (17.3 ± 13.4 vs 4.4 ± 6.2%, p = 0.003). PES had a trend toward higher rate of uncovered and malapposed struts in the ACS groups (6.7 ± 7.6 vs 4.0 ± 9.0%, p = 0.13) while ZES was similar in both groups. CONCLUSION: The patterns of neointimal coverage and malapposition at 9months after DES implantation were different between ACS and SAP, and variable among the DES type between two groups. Therefore, the present study suggests that vascular response after DES implantation might be influenced by both clinical presentation and type of DES.


Asunto(s)
Síndrome Coronario Agudo/patología , Síndrome Coronario Agudo/terapia , Angina de Pecho/patología , Angina de Pecho/terapia , Stents Liberadores de Fármacos , Neointima/patología , Tomografía de Coherencia Óptica , Femenino , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Factores de Tiempo
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