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1.
BMC Plant Biol ; 24(1): 807, 2024 Aug 27.
Artigo em Inglês | MEDLINE | ID: mdl-39187785

RESUMO

Cadmium (Cd) is a biologically non-essential heavy metal, a major soil pollutant, and extremely harmful to plants. The phytohormone methyl jasmonate (MeJA) plays an important role in plant heavy-metal resistance. However, the understanding of the effects of MeJA supply level on alleviating Cd toxicity in plants is limited. Here, we investigated how MeJA regulated the development of physiological processes and cell wall modification in Cosmos bipinnatus. We found that low concentrations of MeJA increased the dry weight of seedlings under 120 µM Cd stress by reducing the transport of Cd from roots to shoots. Moreover, a threshold concentration of exogenous MeJA increased the activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) in plant roots, the concentration of Cd in the root cell wall, and the contents of pectin and hemicellulose 1 polysaccharides, through converting Cd into pectin-bound forms. These results suggested that MeJA mitigated Cd toxicity by modulating root cell wall polysaccharide and functional group composition, especially through pectin polysaccharides binding to Cd, with effects on Cd transport capacity, specific chemical forms of Cd, and homeostatic antioxidant systems in C. bipinnatus.


Assuntos
Acetatos , Cádmio , Ciclopentanos , Oxilipinas , Reguladores de Crescimento de Plantas , Oxilipinas/metabolismo , Ciclopentanos/metabolismo , Acetatos/farmacologia , Cádmio/toxicidade , Reguladores de Crescimento de Plantas/metabolismo , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/metabolismo , Poluentes do Solo/toxicidade , Parede Celular/metabolismo , Parede Celular/efeitos dos fármacos , Plântula/efeitos dos fármacos , Plântula/crescimento & desenvolvimento , Plântula/metabolismo , Antioxidantes/metabolismo , Superóxido Dismutase/metabolismo
2.
New Phytol ; 239(1): 75-86, 2023 07.
Artigo em Inglês | MEDLINE | ID: mdl-36978285

RESUMO

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.


Assuntos
Ecossistema , Florestas , Biomassa , Plantas/anatomia & histologia , Madeira
3.
BMC Cardiovasc Disord ; 23(1): 496, 2023 10 07.
Artigo em Inglês | MEDLINE | ID: mdl-37805479

RESUMO

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.


Assuntos
Doença da Artéria Coronariana , Stents Farmacológicos , Intervenção Coronária Percutânea , Humanos , Doença da Artéria Coronariana/diagnóstico por imagem , Doença da Artéria Coronariana/terapia , Doença da Artéria Coronariana/etiologia , Intervenção Coronária Percutânea/efeitos adversos , Resultado do Tratamento , Colesterol
4.
Ecotoxicol Environ Saf ; 261: 115101, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37290296

RESUMO

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.


Assuntos
Asteraceae , Cádmio , Cádmio/metabolismo , Antioxidantes/farmacologia , Antioxidantes/metabolismo , Ácido Abscísico/farmacologia , Ácido Abscísico/metabolismo , Adsorção , Asteraceae/metabolismo , Parede Celular/metabolismo , Raízes de Plantas/metabolismo
5.
J Interv Cardiol ; 2021: 7099044, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34381321

RESUMO

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.


Assuntos
Intervenção Coronária Percutânea , Angiografia Coronária/efeitos adversos , Humanos , Intervenção Coronária Percutânea/efeitos adversos , Estudos Prospectivos , Artéria Radial , Estudos Retrospectivos
6.
Heart Lung Circ ; 29(12): 1856-1864, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32611501

RESUMO

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.


Assuntos
Técnicas de Ablação/métodos , Cardiomiopatia Hipertrófica/etnologia , Etanol/farmacologia , Etnicidade , Septos Cardíacos/efeitos dos fármacos , Cardiomiopatia Hipertrófica/diagnóstico , Cardiomiopatia Hipertrófica/terapia , China/epidemiologia , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Fatores de Tempo , Resultado do Tratamento
7.
Catheter Cardiovasc Interv ; 93(S1): 825-831, 2019 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-30724035

RESUMO

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.


Assuntos
Anticoagulantes/administração & dosagem , Antitrombinas/administração & dosagem , Oclusão Coronária/terapia , Hemorragia/epidemiologia , Heparina/administração & dosagem , Hirudinas/administração & dosagem , Fragmentos de Peptídeos/administração & dosagem , Intervenção Coronária Percutânea/efeitos adversos , Fatores Etários , Idoso , Anticoagulantes/efeitos adversos , Antitrombinas/efeitos adversos , China/epidemiologia , Doença Crônica , Oclusão Coronária/diagnóstico por imagem , Oclusão Coronária/mortalidade , Trombose Coronária/epidemiologia , Feminino , Hemorragia/induzido quimicamente , Hemorragia/mortalidade , Heparina/efeitos adversos , Hirudinas/efeitos adversos , Humanos , Masculino , Pessoa de Meia-Idade , Infarto do Miocárdio/epidemiologia , Fragmentos de Peptídeos/efeitos adversos , Intervenção Coronária Percutânea/mortalidade , Intervalo Livre de Progressão , Estudos Prospectivos , Proteínas Recombinantes/administração & dosagem , Proteínas Recombinantes/efeitos adversos , Medição de Risco , Fatores de Risco , Fatores de Tempo
8.
Eur J Nucl Med Mol Imaging ; 45(12): 2181-2189, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-30171271

RESUMO

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.


Assuntos
Doença da Artéria Coronariana/diagnóstico por imagem , Placa Aterosclerótica/diagnóstico por imagem , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Fluoreto de Sódio , Ultrassonografia de Intervenção , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
9.
BMC Ecol ; 17(1): 33, 2017 10 30.
Artigo em Inglês | MEDLINE | ID: mdl-29084533

RESUMO

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.


Assuntos
Ecossistema , Florestas , Plantas/classificação , China , Filogenia , Plantas/genética
10.
Chem Commun (Camb) ; 60(67): 8884-8887, 2024 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-39083245

RESUMO

In the preparation of flexible electronic devices, obtaining a transparent conductive electrode with high electrical conductivity, high transparency, and mechanical flexibility is a significant challenge. This study developed a simple method for preparing ultra-long silver nanowires (ul-AgNWs), obtaining high-purity ul-AgNWs with an average length of 317.66 ± 98.60 µm, an average diameter of 78.06 ± 13.87 nm, and an aspect ratio exceeding 4000. Integrating these ul-AgNWs with a polyethylene terephthalate (PET) film, a flexible transparent electrode (FTE) with Rs = 561 Ω and T = 97% was obtained. The ul-AgNWs were welded by driving the welding liquid to the intersection points through surface tension, resulting in a decrease of Rs to 61 Ω, T = 98.2%, and achieving a FTE with excellent mechanical properties. Furthermore, this FTE was applied in the preparation of OLED devices, showing a turn-on voltage of 2.7 V, and the maximum current efficiency and power efficiency reached 58.6 mA cm-2 and 64.7 lm W-1, respectively, demonstrating its significant potential in flexible optoelectronic devices.

11.
Environ Pollut ; 345: 123503, 2024 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-38331243

RESUMO

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.


Assuntos
Acetatos , Asteraceae , Cádmio , Ciclopentanos , Oxilipinas , Cádmio/metabolismo , Raízes de Plantas/metabolismo , Polissacarídeos/metabolismo , Polissacarídeos/farmacologia , Pectinas/química , Parede Celular/metabolismo , Asteraceae/metabolismo
12.
Chemosphere ; 315: 137677, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36608889

RESUMO

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.


Assuntos
Asteraceae , Cromo , Humanos , Cromo/toxicidade , Antioxidantes , Parede Celular
13.
Ecol Evol ; 12(7): e9110, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35845366

RESUMO

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.

14.
Adv Mater ; 34(48): e2108473, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34957614

RESUMO

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.

15.
Ecol Evol ; 11(16): 11362-11372, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34429925

RESUMO

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.

16.
Am Heart J ; 159(2): 278-83, 2010 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-20152227

RESUMO

BACKGROUND: Intracoronary thrombus formation after drug-eluting stent (DES) implantation is not sufficiently evaluated. METHODS: Optical coherence tomography (OCT) was performed in 226 patients (total DES n = 244, sirolimus-eluting stent [SES] n = 95, paclitaxel-eluting stent [PES] n = 62, zotarolimus-eluting stent [ZES] n = 87) after implantation (mean 11 months, range 3-66 months). Using OCT, we investigated the incidence and determinants of intracoronary thrombus. RESULTS: Intracoronary thrombus was detected in 35 (14%) cases (27 SES [28%], 7 PES [11%], and 1 ZES [1%], P < .001) and was associated with longer stent, smaller stent diameter, and stents at bifurcation lesions. More uncovered stent struts (26 +/- 23 vs 8 +/- 17, P < .001) and malapposed stent struts (6 +/- 14 vs 2 +/- 6, P < .001) were also associated with intracoronary thrombus. Multiple logistic regression analysis found the following determinants of intracoronary thrombus: stent length > or =28 mm (odds ratio [OR] 7.31, 95% CI 1.79-29.86, P = .01), stent diameter <3.0 mm (OR 4.38, 95% CI 1.38-13.97, P = .01), and > or =8 uncovered struts in each stent (OR 3.29, 95% CI 1.07-10.17, P = .04). CONCLUSIONS: Length, size, and types of DES may be more important than clinical factors in intracoronary thrombus formation after DES implantations.


Assuntos
Trombose Coronária/diagnóstico , Trombose Coronária/etiologia , Stents Farmacológicos/efeitos adversos , Tomografia de Coerência Óptica , Trombose Coronária/epidemiologia , Feminino , Seguimentos , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , Fatores de Tempo
17.
Circ J ; 74(2): 320-6, 2010 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-20019414

RESUMO

BACKGROUND: The differences between using sirolimus-eluting stents (SESs) and paclitaxel-eluting stents (PESs) in the vascular response at 9 months after implantation were examined with optical coherence tomography (OCT). METHODS AND RESULTS: OCT was carried out in 33 SESs [33 patients, 19 with acute coronary syndrome (ACS) and 14 with stable angina pectoris (SAP)] and 27 PESs (27 patients, 15 with ACS and 12 with SAP) at 9 months after stent implantation. Stent strut coverage and apposition at each strut were evaluated. The frequency of uncovered struts was significantly higher in SES (12.5+/-15.2 vs 4.9+/-7.9 %, P=0.01). The incidence of complete covered stents with neointima was 9.1% (3/33) in SES and 29.6% (8/27) in PES (P=0.05). The pattern of neointima in PES was more heterogeneous than that in SES (1.3+/-0.5 for SES vs 2.0+/-0.6 for PES, P<0.001). The intracoronary thrombus was frequently detected in SES [10 (30.3%) in SES vs 5 (18.5%) in PES, P=0.29]. CONCLUSIONS: Uncovered struts were frequently observed in SES, but the pattern of neointima was more heterogeneous in PES at 9 months. In addition, stent coverage was incomplete in both stent groups at 9 months after stent implantation.


Assuntos
Angioplastia Coronária com Balão/instrumentação , Fármacos Cardiovasculares/administração & dosagem , Doença da Artéria Coronariana/terapia , Vasos Coronários/patologia , Stents Farmacológicos , Paclitaxel/administração & dosagem , Sirolimo/administração & dosagem , Tomografia de Coerência Óptica , Túnica Íntima/patologia , Idoso , Angioplastia Coronária com Balão/efeitos adversos , Angiografia Coronária , Doença da Artéria Coronariana/patologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Desenho de Prótese , Sistema de Registros , Trombose/etiologia , Trombose/patologia , Fatores de Tempo , Resultado do Tratamento
18.
Ecol Evol ; 10(15): 8225-8234, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32788974

RESUMO

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.

19.
Nucleic Acids Res ; 33(Database issue): D485-91, 2005 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-15608243

RESUMO

The Rat Genome Database (RGD) (http://rgd.mcw.edu) aims to meet the needs of its community by providing genetic and genomic infrastructure while also annotating the strengths of rat research: biochemistry, nutrition, pharmacology and physiology. Here, we report on RGD's development towards creating a phenome database. Recent developments can be categorized into three groups. (i) Improved data collection and integration to match increased volume and biological scope of research. (ii) Knowledge representation augmented by the implementation of a new ontology and annotation system. (iii) The addition of quantitative trait loci data, from rat, mouse and human to our advanced comparative genomics tools, as well as the creation of new, and enhancement of existing, tools to enable users to efficiently browse and survey research data. The emphasis is on helping researchers find genes responsible for disease through the use of rat models. These improvements, combined with the genomic sequence of the rat, have led to a successful year at RGD with over two million page accesses that represent an over 4-fold increase in a year. Future plans call for increased annotation of biological information on the rat elucidated through its use as a model for human pathobiology. The continued development of toolsets will facilitate integration of these data into the context of rat genomic sequence, as well as allow comparisons of biological and genomic data with the human genomic sequence and of an increasing number of organisms.


Assuntos
Bases de Dados de Ácidos Nucleicos , Genômica , Fenótipo , Ratos/genética , Animais , Mapeamento Cromossômico , Sistemas de Gerenciamento de Base de Dados , Modelos Animais de Doenças , Marcadores Genéticos , Genoma , Locos de Características Quantitativas , Ratos/fisiologia , Integração de Sistemas
20.
Ecol Evol ; 7(23): 10116-10123, 2017 12.
Artigo em Inglês | MEDLINE | ID: mdl-29238541

RESUMO

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.

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