Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 46
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Sci Rep ; 10(1): 4735, 2020 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-32170188

RESUMO

Surveying the quality and quantity of carbon stock in litter layer and woody debris of Eucalyptus and Acacia plantations is critical in understanding their carbon pools. Here, the focus of the present study was on a number of Eucalyptus and Acacia plantations of different stand aged in the Pearl River Delta region of southern China. The plantation type proved to be a crucial driver of the carbon concentration in litter layer and woody debris, with Acacia exhibiting a superior ability to Eucalyptus to accumulate carbon with stand age in both these materials. The relative contribution of the litter layer and woody debris to the carbon stock of the ecosystem was also significantly higher under mature Acacia (8% and 7%, respectively) than that under mature Eucalyptus (4% and 1%, respectively). Most of the carbon stock within the litter layer was present in the leaf debris. The carbon stock in woody debris was mainly contained in the components within the 10-20 cm diameter class during the primary decay stage, represented as snags in middle-aged and mature Acacia, and as logs for mature Eucalyptus, respectively. The results indicate that both plantation type and stand age influence the characteristics of carbon stored in litter layer and woody debris significantly.

2.
Environ Pollut ; 262: 114215, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32142975

RESUMO

Microbial attributes have a great impact on soil heavy metal bioavailability, yet their influencing pathway on heavy metal accumulation in crop plants remains elusive. This study was aimed to analyze the influencing pathways of microbial attributes, including microbial biomass C and N (MBC and MBN), basal soil respiration (BSR) along with the activities of catalase, urease, and sucrase, on heavy metals (i.e., Cd, Cr, Cu, Ni, Pb, and Zn) accumulation by brassica leaves. Based upon a field investigation close to electroplating factory outlets, 45 pairs of soil and brassica samples were analyzed in the laboratory. Concentrations of heavy metals in brassica leaves declined with sampling distances downstream from the outlets. Redundancy analysis indicated that bioavailable concentrations of Cr, Cu, Ni, and MBC along with catalase activity were the major variables influencing heavy metal accumulation in brassica leaves and accounted for 83% of the accumulation. MBC and catalase activity accounted for 17% of the heavy metal accumulation in brassica leaves. Stepwise regression indicated that catalase activity, MBC, and BSR significantly affected heavy metal accumulation in brassica leaves. Based on structural equation modeling, the pathway coefficient of microbial activities-brassica heavy metals and the pathway coefficient of microbial biomass-brassica heavy metals are 0.122 (P < 0.05), suggesting that these microbial attributes (i.e. MBC along with catalase activities and SBR) could affect heavy metal accumulation in brassica leaves directly. The pathway coefficients of microbial activities-bioavailable heavy metals-brassica heavy metals and microbial biomass-bioavailable heavy metals-brassica heavy metal were -0.541 (P < 0.001) and 0.453 (P < 0.001), respectively, indicating that increase of microbial activities inhibited heavy metal accumulation while increase of microbial biomass promoted heavy metal accumulation, in brassica leaves. These results suggested that heavy metal bioavailability played a mediating role in the influencing pathways of soil microbial attributes on heavy metals in brassica leaves.

3.
Sci Total Environ ; 714: 136742, 2020 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-32018964

RESUMO

Despite carbon sequestration being an important service of mangrove ecosystems, many mangrove reforestation projects have little consideration of the carbon sequestration capacity of species to be planted. Species selection is mostly based on growth rate and convenience in planting. In this study, to compare the quantity and quality of carbon stored in soil, four habitats were selected in Haijiang River Estuary, southern China to assess the contribution by different mangrove species to sediment carbon pool. Two 12-year-old mangrove forests of the exotic Sonneratia apetala and native Kandelia obovata, respectively, and the adjacent sandflat and mudflat as unvegetated referencing sites had been studied. The total sedimentary organic carbon and active sedimentary organic content in sediment suggested that after 12 years of growth, (1) mangrove forests significantly increased the organic carbon content of sediment; (2) total organic carbon in the K. obovata forest was higher than that of the S. apetala forest; but (3) the carbon pool of the K. obovata forest was less stable than that of the S. apetala forest. These results corroborated with other studies that the sediment carbon pool of S. apetala forests reached a stable state after 13 years of growth, while that of K. obovata forests gradually stabilised upon long-term (>13 years) growth. Our study confirms that K. obovata is more conducive to capture carbon in long-term mangrove reforestation projects, demonstrating that the provision of this service may not be directly related to apparently relevant plant traits such as growth rate.


Assuntos
Sequestro de Carbono , Carbono , China , Florestas , Rhizophoraceae , Áreas Alagadas
4.
Sci Total Environ ; 717: 137142, 2020 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-32070894

RESUMO

Carbon storage is one of the main objectives for mangrove afforestation. Planting of the exotic species Sonneratia apetala can rapidly increase the mangrove area and biomass. Here, we studied the change in vegetation and the soil carbon stocks along the chronosequence of S. apetala plantations in Qi'ao Island, China. Five sites, including rehabilitated S. apetala of different ages (1, 4, 9, and 15 years) and 40-year-old mature native Kandelia obovata forests were investigated. Vegetation biomass and the soil carbon content from 0 to 100 cm were analyzed. The ecosystem carbon density (vegetation and soil) was then calculated. A positive and linear relationship was observed between the vegetation carbon stocks and age of S. apetala. The 15-year-old S. apetala already had a similar biomass to 40-year-old K. obovata. However, its soil and ecosystem carbon densities remained lower than those of K. obovata. Different from K. obovata, the majority of the biomass of S. apetala was reserved within the stem. Mature K. obovata had a larger proportion of soil carbon stock to ecosystem carbon stock. S. apetala can accumulate biomass rapidly, but it had a lower ecosystem carbon stock than the native mature K. obovata.


Assuntos
Ecossistema , Biomassa , Carbono , China , Ilhas , Qi , Solo
5.
Int J Biol Macromol ; 2019 Nov 19.
Artigo em Inglês | MEDLINE | ID: mdl-31756487

RESUMO

OBJECTIVE: Fas is a positive regulator of Th17 cells differentiation in experimental autoimmune encephalomyelitis (EAE). However, its upstream regulators are still not fully determined. This study was designed to explore the upstream regulators of Fas in regulating Th17 cells differentiation in EAE. METHODS: The mouse model of EAE was established by myelin oligodendrocyte glycoprotein injection. Th17 cells differentiation was induced by IL-23, IL-6 and TGF-ß. RESULTS: Down-regulated Hsp70 and miR-374c and up-regulated Fas were observed in the spleen and brain of EAE mice. Hsp70 overexpression evidently reduced Fas protein level, but not mRNA level. The luciferase reporter assay indicated that miR-374c targets Fas. Overexpression of miR-374c down-regulated the mRNA and protein level of Fas. The concentration of IL-17A in CD4+ T-cells was reduced by miR-374c or Hsp70 overexpression, and Fas overexpression altered this trend. Hsp70 did not regulate the expression of miR-374c, and likewise, miR-374c did not regulate the expression of Hsp70. Further results suggested that Hsp70 and miR-374c regulated Fas expression through different ways to affect Th17 cells differentiation in EAE. CONCLUSIONS: This study suggested that down-regulated miR-374c and Hsp70 promote Th17 cell differentiation by inducing Fas expression in EAE.

6.
Mar Pollut Bull ; 149: 110581, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31550580

RESUMO

This study aimed to assess how sediment organic carbon (SOC) dynamics were affected by mangrove community structures. Sediment attributes and community structures of the Avicennia marina, Aegiceras corniculatum, Rhizophora stylosa, and Bruguiera gymnorrhiza communities were analyzed, based upon field investigation in Yingluo Bay of South China. Aboveground biomass (AGB), belowground biomass (BGB) and tree height obviously increased with the self-thinning process, while basal area significantly decreased. The self-thinning exponent was 1.382 for AGB and 1.254 for BGB, conforming to the 4/3 self-thinning rule. However, self-thinning exponent for basal area was only 0.4866. SOC content non-linearly increased with the increase of AGB, BGB, and tree height. Mangrove-derived carbon increased through in situ organic material inputs with mangrove growth. The negative correlation between tree density and SOC content was not in line with the previous studies for planted mangroves. SOC dynamics of natural mangroves may be partially different from planted mangroves.


Assuntos
Carbono/análise , Sedimentos Geológicos/análise , Áreas Alagadas , Avicennia , Baías , Biomassa , China , Sedimentos Geológicos/química , Concentração de Íons de Hidrogênio , Primulaceae , Rhizophoraceae , Salinidade , Árvores
7.
Environ Sci Pollut Res Int ; 26(22): 22596-22610, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31165447

RESUMO

Comprehensive understanding of the influence of soil properties on the potential availability of heavy metals could facilitate soil environment management. This study investigated the distribution of heavy metals and their potential availability in paddy and vegetable fields around electroplating factory outlets and irrigated with its wastewater. The potential availability was assessed using secondary phase fraction (SPF) of heavy metals, including acid-soluble, reducible, and oxidizable fractions resulting from BCR sequential extraction procedure. In total, 94 of topsoil samples (0-20 cm) were collected. Total and SPF concentrations of heavy metals as well as soil physicochemical properties were determined. Multivariable statistical analyses (i.e., principal component analysis (PCA) and redundancy analysis (RDA)) were employed. Results showed that total and SPF concentrations of heavy metals in soil decreased (P<0.05) as sampling distance away from the electroplating factories increased, suggesting that sampling distance was the major parameter that affected gradient variations of both total and potential availability of soil heavy metals. According to PCA, soil samples distributed on the PCA axis representing anthropogenic effect, illustrating that the variation of soil properties resulted from irrigation with electroplating wastewater. RDA and stepwise regression indicated that soil Mn oxides, amorphous Fe oxides, silt content, and pH could explain 68.8% and 43.5% of the variation of SPF concentration in paddy and vegetable garden soil, respectively, suggesting they were the most important factors influencing the potential availability of heavy metals in soils. The potential availability of heavy metals in soil was positively correlated with soil Mn oxides but negatively associated with soil amorphous Fe oxides, indicating that Mn oxides enhanced the potential availability of heavy metals while amorphous Fe oxides reduced the potential availability.


Assuntos
Galvanoplastia , Monitoramento Ambiental , Metais Pesados/análise , Poluentes do Solo/análise , Solo/química , Verduras
8.
Biosci Rep ; 39(4)2019 04 30.
Artigo em Inglês | MEDLINE | ID: mdl-30910847

RESUMO

Using a case-control design, we assessed the association between single nucleotide polymorphisms of CYP3A4 gene rs4646437 polymorphism and the risk of hypertension in Chinese population. We recruited 450 hypertension patients from The First Clinical College, Henan University of Chinese Medicine between June 2017 and May 2018. There was a significant difference in genotype distribution between case group and control group (χ2 =18.169, P=0.000). The minor A allele was significantly higher in the case group than that in the control group (31.0 vs 24.8%, P=0.000, odds ratio [OR]=1.36, 95% confidence interval [95% CI]: 1.12-1.66). Significant differences were also observed in other gene models: the GA/AA genotype did not increase the risk of hypertension compared with GG genotype (OR=1.16, 95% CI: 0.90-1.49, P=0.259). Compared with GG/GA genotype, the AA genotype also increased the risk of hypertension (OR=2.34, 95% CI: 1.56-3.50, P=0.000). For additive model, the AA genotype was significantly associated with GG genotype (OR=2.25, 95% CI: 1.49-3.42, P=0.000). The same results were found for AA vs GA (OR=2.50, 95% CI: 1.60-3.89, P=0.000). For the allele genotype, the A allele frequency was significantly higher in the case group than that in the control group (31.0 vs 24.8%, P=0.002). The A allele of CYP3A4 rs4646437 was associated with an increased risk for hypertension (OR=1.36, 95% CI: 1.12-1.66, P=0.002). Our results revealed a possible genetic association between CYP3A4 gene rs4646437 and hypertension, and the AA genotype of rs4646437 increased the risk of hypertension in Chinese Han population, and this effect could be confirmed by multivariable analyses.

9.
Biosci Rep ; 39(2)2019 02 28.
Artigo em Inglês | MEDLINE | ID: mdl-30777926

RESUMO

Using a case-control design, we assessed the association between single nucleotide polymorphisms (SNPs) of growth and differentiation factor 5 (GDF5)/rs143383 gene and interaction with environments and knee osteoarthritis (KOA). We recruited 288 KOA patients from the First Clinical College, Henan University of Chinese Medicine between June 2017 and May 2018. There was significant difference in genotype distribution between case group and control group (χ2 = 22.661, P=0.000). The minor C allele was significantly higher in the case group than that in the control group (20.5 vs 8.1%, P=0.000, odds ratio (OR) = 1.62, 95% confidence interval (CI): 1.29-2.03). Significant differences were also observed in other gene models. For age, all models show significant differences (P<0.05) for those whose age was more than 60 years, and no significant difference was observed for those under 60 years. For non-smoking group, there were significant differences between case group and control group, and for smoker, significance level was found in TT compared with CC and allele gene models. Patients with drinking and Bbody mass index (MI )≥ 24 also showed significant relationship between rs143383 and osteoarthritis (OA) under the following models: TT vs CC (P=0.000, P=0.018), TT/CT vs CC (P=0.043), TT vs CT/CC (P=0.000, P=0.009), and T vs C (P=0.024, P=0.000). Other gene models indicated no significance (P>0.05). Our results revealed a possible genetic association between GDF5 and KOA, and the TT genotype of rs143383 increased the risk of KOA in Chinese Han population. The interaction between GDF5 gene and drinking, smoking, and obesity further increased the risk of KOA.


Assuntos
Fator 5 de Diferenciação de Crescimento/genética , Osteoartrite do Joelho/genética , Polimorfismo de Nucleotídeo Único , Grupo com Ancestrais do Continente Asiático/genética , Estudos de Casos e Controles , China/epidemiologia , Feminino , Interação Gene-Ambiente , Predisposição Genética para Doença , Humanos , Masculino , Pessoa de Meia-Idade , Osteoartrite do Joelho/epidemiologia
10.
J Environ Manage ; 232: 781-788, 2019 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-30529865

RESUMO

Subtropical forests function as important carbon sinks for atmospheric CO2. Nonetheless, there remain uncertainties about the effects of climate and topography on subtropical forest biomass-carbon stocks. A continuous biomass expansion factor (BEF) method was applied to forest inventory data to estimate biomass-carbon storage and carbon sink rate, and their changes along with abiotic and biotic factors in the Pearl River Delta (PRD) of South China. BEF equations were built using a set of field-based data. Biomass-carbon increased from 62.92 to 70.56 Mt along with forest growth and increasing forest area during the latest two periods of the national forest inventory (2004-8 and 2009-13). The PRD's forests continued to be net carbon sinks 0.51 t ha-1 yr-1. The PRD's forests have a high potential as biomass-carbon sinks in the future, because 46.75% of the forests are at the young or middle-aged stage. In addition, principal component analysis indicated that both biomass-carbon density and carbon sink rate were positively correlated with the area percentage of mature and over-mature forests, average annual precipitation and minimum temperature, but they were negatively correlated with average annual maximum temperature. Pearson correlation analysis demonstrated that biomass-carbon density and carbon sink rate affected by average altitude, while they were not related to the slope angle.


Assuntos
Carbono , Rios , Biomassa , Sequestro de Carbono , China , Florestas , Árvores
11.
Neurology ; 90(17): e1523-e1529, 2018 04 24.
Artigo em Inglês | MEDLINE | ID: mdl-29572284

RESUMO

OBJECTIVE: To investigate the efficacy and safety of IV aminophylline for patients with postdural puncture headache (PDPH). METHODS: We randomly assigned patients to groups receiving either 250 mg IV aminophylline or a placebo within 3 hours of symptom onset once daily for 2 consecutive days. The primary endpoint was headache severity 8 hours after treatment. We assessed this using visual analog scale (VAS) scores taken from patients in a standing position. We also recorded posttreatment VAS score changes, Patient Global Impression of Change (PGIC) scores, and adverse events. We performed an intention-to-treat analysis. RESULTS: We enrolled 126 patients with PDPH at 5 centers in China (62 assigned to the aminophylline group and 64 to the placebo group). The median age was 37 years, and 96 (76.2%) patients were women. Compared to the placebo-treated patients, the aminophylline-treated patients had significantly lower mean VAS scores 8 hours after treatment (5.34 vs 2.98, p < 0.001) and were significantly more likely to report improvements on the PGIC (39.1% vs 72.6%, p < 0.01). This therapeutic effect was already evident at the 30-minute time point and persisted for 2 days. There was no significant difference in the incidence of adverse events (4.8% vs 1.6%, p = 0.589). CONCLUSIONS: IV aminophylline is an effective and safe early-stage treatment for patients with PDPH. CLINICALTRIALSGOV IDENTIFIER: NCT02522013. CLASSIFICATION OF EVIDENCE: This study provides Class I evidence that for people with PDPH, IV aminophylline reduces headache severity.


Assuntos
Aminofilina/uso terapêutico , Inibidores de Fosfodiesterase/uso terapêutico , Cefaleia Pós-Punção Dural/tratamento farmacológico , Administração Intravenosa , Adolescente , Adulto , Idoso , Método Duplo-Cego , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estatísticas não Paramétricas , Resultado do Tratamento , Escala Visual Analógica , Adulto Jovem
12.
Sci Rep ; 7(1): 13173, 2017 10 13.
Artigo em Inglês | MEDLINE | ID: mdl-29030630

RESUMO

Forest fragmentation threatens the ecosystem carbon (C) storage. The distribution patterns of ecosystem C density are poorly documented for fragmented forests of differing patch size. The objectives of this study were to examine C density in these forest ecosystems and the influence of edge effects on C density. Allometric equations were used to quantify aboveground biomass. Carbon density was estimated by analyzing the C concentration of each component. We found that ecosystem carbon density ranged from 173.9 Mg ha-1 in the small sized forest fragments, to 341.1 Mg ha-1 in the contiguous evergreen sub-tropical forest. Trees (46.5%) and mineral soil (50.2%) were the two largest contributors to the total ecosystem C pool in all fragments. Both C and nitrogen (N) in soil and fine roots were highly heterogeneous among the different fragment sizes and soil depths. We concluded that ecosystem C density of forest fragments were significantly influenced by patch size and edge effects. The fragmented forests in southern China play an important role in the C budget, and need urgent conservation. These results are likely to be further integrated into forest management plans and generalized into other contexts, to evaluate C stocks at the landscape scale.


Assuntos
Biomassa , Carbono/análise , Ecossistema , China , Florestas , Nitrogênio/análise , Raízes de Plantas/metabolismo
13.
Chemosphere ; 185: 868-878, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-28746996

RESUMO

A field-based study was undertaken to analyze the effects of soil bioavailable heavy metals determined by a sequential extraction procedure, and soil microbial parameters on the heavy metal accumulation in rice grain. The results showed that Cd, Cr, Cu, Ni, Pb and Zn concentrations in rice grain decreases by 65.9%, 78.9%, 32.6%, 80.5%, 61.0% and 15.7%, respectively in the sites 3 (far-away), compared with those in sites 1 (close-to). Redundancy analysis (RDA) indicated that soil catalase activity, the MBC/MBN ratio, along with bioavailable Cd, Cr and Ni could explain 68.9% of the total eigenvalue, indicating that these parameters have a great impact on the heavy metal accumulation in rice grain. The soil bioavailable heavy metals have a dominant impact on their accumulation in rice grain, with a variance contribution of 60.1%, while the MBC/MBN has a regulatory effect, with a variance contribution of 4.1%. Stepwise regression analysis showed that the MBC/MBN, urease and catalase activities are the key microbial parameters that affect the heavy metal accumulation in rice by influencing the soil bioavailable heavy metals or the translocation of heavy metals in rice. RDA showed an interactive effect between Cu, Pb and Zn in rice grain and the soil bioavailable Cd, Cr and Ni. The heavy metals in rice grain, with the exception of Pb, could be predicted by their respective soil bioavailable heavy metals. The results suggested that Pb accumulation in rice grain was mainly influenced by the multi-metal interactive effects, and less affected by soil bioavailable Pb.


Assuntos
Metais Pesados/análise , Oryza/química , Microbiologia do Solo , Poluentes do Solo/análise , Grão Comestível/química , Monitoramento Ambiental , Metais Pesados/toxicidade , Solo/química , Poluentes do Solo/toxicidade , Urease
14.
Phys Chem Chem Phys ; 19(7): 4956-4961, 2017 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-28155953

RESUMO

The electron transport layer (ETL) plays a critical role in high efficiency perovskite solar cells. In this study, an anodic TiO2 nanotube film was transformed into a TiO2 nanotube network film, which maintained its advantage as an efficient ETL for perovskite solar cells. Compared with the mesoporous TiO2 nanoparticle ETL, the TiO2 nanotube network ETL can increase the efficiency of perovskite solar cells by 26.6%, which is attributed to its superior charge collection property and light trapping ability. The results confirm the importance of optimizing the electron collecting layer and suggest another way to design and fabricate novel perovskite solid state solar cells, potentially by using a TiO2 nanotube network film as an alternative high efficiency electrode.

15.
Environ Sci Pollut Res Int ; 24(3): 2558-2571, 2017 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-27826825

RESUMO

This study was carried out to examine heavy metal accumulation in rice grains and brassicas and to identify the different controls, such as soil properties and soil heavy metal fractions obtained by the Community Bureau of Reference (BCR) sequential extraction, in their accumulation. In Guangdong Province, South China, rice grain and brassica samples, along with their rhizospheric soil, were collected from fields on the basis of distance downstream from electroplating factories, whose wastewater was used for irrigation. The results showed that long-term irrigation using the electroplating effluent has not only enriched the rhizospheric soil with Cd, Cr, Cu, and Zn but has also increased their mobility and bioavailability. The average concentrations of Cd and Cr in rice grains and brassicas from closest to the electroplating factories were significantly higher than those from the control areas. Results from hybrid redundancy analysis (hRDA) and redundancy analysis (RDA) showed that the BCR fractions of soil heavy metals could explain 29.0 and 46.5 % of total eigenvalue for heavy metal concentrations in rice grains and brassicas, respectively, while soil properties could only explain 11.1 and 33.4 %, respectively. This indicated that heavy metal fractions exerted more control upon their concentrations in rice grains and brassicas than soil properties. In terms of metal interaction, an increase of residual Zn in paddy soil or a decrease of acid soluble Cd in the brassica soil could enhance the accumulation of Cd, Cu, Cr, and Pb in both rice grains and brassicas, respectively, while the reducible or oxidizable Cd in soil could enhance the plants' accumulation of Cr and Pb. The RDA showed an inhibition effect of sand content and CFO on the accumulation of heavy metals in rice grains and brassicas. Moreover, multiple stepwise linear regression could offer prediction for Cd, Cu, Cr, and Zn concentrations in the two crops by soil heavy metal fractions and soil properties.


Assuntos
Brassica , Oryza , Poluentes do Solo/análise , Irrigação Agrícola , China , Produtos Agrícolas , Grão Comestível/química , Metais Pesados/análise , Solo , Águas Residuárias/análise
16.
Pain Physician ; 19(5): E761-5, 2016 07.
Artigo em Inglês | MEDLINE | ID: mdl-27389119

RESUMO

BACKGROUND: Post-dural puncture headache (PDPH) is the most common complication of lumbar puncture. Aminophylline has been reported to be effective in the prevention of PDPH in some clinical studies, but its efficacy for the treatment of PDPH has been unproven. OBJECTIVE: To evaluate the efficacy and safety of an intravenous (IV) injection of aminophylline on PDPH. STUDY DESIGN: The study was a multicenter, open-label study to assess the effectiveness and safety of aminophylline on PDPH. SETTING: The First Affiliated Hospital of Zhengzhou University, The Fifth Affiliated Hospital of Zhengzhou University, and Henan Province Hospital of Traditional Chinese Medicine. METHODS: Thirty-two PDPH patients received an IV injection of aminophylline. The primary and secondary endpoints were the degree of headache and the patient's overall response to the treatment, respectively. Treatment safety was evaluated based on the occurrence of adverse reactions. RESULTS: Thirty-one patients completed the study. Before the initial aminophylline administration, the visual analog scale (VAS) score was 7.72 ± 1.65. The VAS scores at 30 minutes, one hour, 8 hours, one day, and 2 days post-treatment were 4.84 ± 2.53, 3.53 ± 2.06, 2.38 ± 1.96, 1.44 ± 1.87, and 0.81 ± 1.79, respectively, and were statistically significantly different (P < 0.05) compared with those before treatment. More than 50% (17/32) of the patients reported that they were "very much improved" or "much improved" 30 minutes after the initial treatment, increasing to 93.8% (30/32) at 2 days post-treatment. One patient experienced mild allergic reaction after treatment. LIMITATIONS: Although this study had the largest sample size among current studies on treating PDPH with theophylline drugs, the sample size was still relatively small and the method employed was not compared with a placebo or other current clinical treatments for PDPH. CONCLUSION: An IV injection of aminophylline may be an effective and safe early-stage treatment for PDPH.


Assuntos
Aminofilina/farmacologia , Cefaleia Pós-Punção Dural/tratamento farmacológico , Antagonistas de Receptores Purinérgicos P1/farmacologia , Adulto , Idoso , Aminofilina/administração & dosagem , Feminino , Humanos , Injeções Intravenosas , Masculino , Pessoa de Meia-Idade , Antagonistas de Receptores Purinérgicos P1/administração & dosagem , Resultado do Tratamento , Adulto Jovem
17.
Sci Rep ; 6: 22561, 2016 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-26940005

RESUMO

Tree mortality and recruitment are key factors influencing forest dynamics, but the driving mechanisms of these processes remain unclear. To better understand these driving mechanisms, we studied forest dynamics over a 5-year period in a 20-ha sub-tropical forest in the Dinghushan Nature Reserve, South China. The goal was to identify determinants of tree mortality/recruitment at the local scale using neighborhood analyses on some locally dominant tree species. Results show that the study plot was more dynamic than some temperate and tropical forests in a comparison to large, long-term forest dynamics plots. Over the 5-year period, mortality rates ranged from 1.67 to 12.33% per year while recruitment rates ranged from 0 to 20.26% per year. Tree size had the most consistent effect on mortality across species. Recruitment into the ≥1-cm size class consistently occurred where local con-specific density was high. This suggests that recruitment may be limited by seed dispersal. Hetero-specific individuals also influenced recruitment significantly for some species. Canopy species had low recruitment into the ≥1-cm size class over the 5-year period. In conclusion, tree mortality and recruitment for sixteen species in this plot was likely limited by seed dispersal and density-dependence.


Assuntos
Ecossistema , Florestas , Sementes/fisiologia , Árvores/fisiologia , Clima Tropical , China , Ecologia , Modelos Biológicos , Especificidade da Espécie , Fatores de Tempo
18.
Phys Chem Chem Phys ; 18(6): 4643-51, 2016 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-26794602

RESUMO

Band gap opening and modulating are critical in dictating the functionalities of single walled carbon nanotubes (SWCNTs) in a broad array of nano-devices. Using first-principles density functional theory calculations, a class of semiconducting armchair SWCNTs with a distinctive BN line defect are studied, showing a super capacity to open the band gap of (4, 4) SWCNT to as large as 0.86 eV, while the opened band gap are found decreasing with the increasing diameters of SWCNTs. The opened band gap of SWCNTs can also be successfully modulated through both mechanical and electrical approaches by applying compressive uniaxial strain and electric field. This study provides novel insights into the large band gap opening and modulating of SWCNTs and could be useful in facilitating future applications of SWCNTs in electronic, optical and thermoelectric devices.

19.
Sci Rep ; 5: 12544, 2015 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-26218269

RESUMO

The multiwalled carbon nanotubes/BaFe12O19-chitosan (MCNTs/BF-CS) Schiff base Ag (I) complex composites were synthesized successfully by a chemical bonding method. The morphology and structures of the composites were characterized with electron microscopy, Fourier transform infrared spectroscopy and X-ray diffraction techniques. Their conductive properties were measured using a four-probe conductivity tester at room temperature, and their magnetic properties were tested by a vibrating sample magnetometer. The results show that the BF-CS Schiff base Ag (I) complexes are embedded into MCNT networks. When the mass ratio of MCNTs and BF-CS Schiff base is 0.95:1, the conductivity, Ms (saturation magnetization), Mr (residual magnetization), and Hc (coercivity) of the BF-CS Schiff base composites reach 1.908 S cm(-1), 28.20 emu g(-1), 16.66 emu g(-1) and 3604.79 Oe, respectively. Finally, a possible magnetic mechanism of the composites has also been proposed.

20.
J Neurochem ; 134(3): 551-65, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-25952107

RESUMO

Hypoxia-mediated neurotoxicity contributes to various neurodegenerative disorders, including Alzheimer's disease and multiple sclerosis. Tetramethylpyrazine (TMP), a major bioactive component purified from Ligusticum wallichii Franchat, exhibited potent neuroprotective effect. However, the mechanism of TMP-exerted neuroprotective effect against hypoxia was not clear. In the study, we investigated the mechanism of the neuroprotective effect of TMP against hypoxia induced by CoCl2 in vitro and in vivo. The results showed that TMP could protect against CoCl2 -induced neurotoxicity in PC12 cells and in rats, as evidenced by enhancement of cell viability in PC12 cells and improvement of learning and memory ability in rats treated with CoCl2 . TMP could inhibit mitochondrial dysfunction, mitochondrial apoptotic molecular events, and thus apoptosis induced by CoCl2 . TMP inhibited CoCl2 -increased reactive oxygen species (ROS) level, which may contribute to hypoxia-related neurotoxicity induced by CoCl2 . The antioxidant and neuroprotective activities of TMP involved two pathways: one was the enhancement of nuclear factor erythroid 2-related factor 2 (Nrf2)/catalytic subunit of γ-glutamylcysteine ligase-mediated regulation of GSH and the other was the inhibition of hypoxia-inducible factor 1 α/NADPH oxidase 2 (NOX2)-mediated ROS generation. These two pathways contributed to improvement of oxidative stress and thus the amelioration of apoptosis under hypoxic conditions. These results have appointed a new path toward the understanding of pathogenesis and TMP-related therapy of hypoxia-related neurodegenerative diseases. We proposed two cascades for tetramethylpyrazine-exhibited protective effects against CoCl2 -induced neurotoxicity: One is enhancement of nuclear factor erythroid 2-related factor 2-catalytic subunit of γ-glutamylcysteine ligase-mediated regulation of glutathone and the other was the inhibition of hypoxia-inducible factor 1 α-NADPH oxidase-2-mediated ROS generation. We think these findings should provide a new understanding of pathogenesis and tetramethylpyrazine-related therapy of hypoxia-related neurodegenerative diseases.


Assuntos
Hipóxia Celular/efeitos dos fármacos , Fármacos Neuroprotetores/farmacologia , Pirazinas/farmacologia , Transdução de Sinais/efeitos dos fármacos , Animais , Apoptose/efeitos dos fármacos , Western Blotting , Imunoprecipitação da Cromatina , Cobalto/toxicidade , Glutamato-Cisteína Ligase/metabolismo , Glutationa/metabolismo , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Masculino , Glicoproteínas de Membrana/metabolismo , NADPH Oxidase 2 , NADPH Oxidases/metabolismo , Fator 2 Relacionado a NF-E2/metabolismo , Células PC12 , Ratos , Ratos Wistar , Espécies Reativas de Oxigênio/metabolismo , Transfecção
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA