Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 33
Filtrar
Mais filtros

Base de dados
País/Região como assunto
Tipo de documento
País de afiliação
Intervalo de ano de publicação
1.
Sensors (Basel) ; 23(17)2023 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-37688024

RESUMO

Sensor nodes are widely distributed in the Internet of Things and communicate with each other to form a wireless sensor network (WSN), which plays a vital role in people's productivity and life. However, the energy of WSN nodes is limited, so this paper proposes a two-layer WSN system based on edge computing to solve the problems of high energy consumption and short life cycle of WSN data transmission and establishes wireless energy consumption and distance optimization models for sensor networks. Specifically, we propose the optimization objective of balancing load and distance factors. We adopt an improved sparrow search algorithm to evenly distribute sensor nodes in the system to reduce resource consumption, consumption, and network life. Through the simulation experiment, our method is illustrated, effectively reducing the network's energy consumption by 26.8% and prolonging the network's life cycle.

2.
Entropy (Basel) ; 25(5)2023 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-37238567

RESUMO

Currently, research on the evolution of heterogeneous combat networks (HCNs) mainly focuses on the modeling process, with little attention paid to the impact of changes in network topology on operational capabilities. Link prediction can provide a fair and unified comparison standard for network evolution mechanisms. This paper uses link prediction methods to study the evolution of HCNs. Firstly, according to the characteristics of HCNs, a link prediction index based on frequent subgraphs (LPFS) is proposed. LPFS have been demonstrated on a real combat network to be superior to 26 baseline methods. The main driving force of research on evolution is to improve the operational capabilities of combat networks. Adding the same number of nodes and edges, 100 iterative experiments demonstrate that the evolutionary method (HCNE) proposed in this paper outperforms random evolution and preferential evolution in improving the operational capabilities of combat networks. Furthermore, the new network generated after evolution is more consistent with the characteristics of a real network.

3.
Zhonghua Nan Ke Xue ; 29(12): 1038-1042, 2023 Dec.
Artigo em Zh | MEDLINE | ID: mdl-38639959

RESUMO

Image fusion technology had been widely applied in image guided radiotherapy (IGRT) for prostate cancer (PCa) based on the gold fiducial mark (GFM). Image fusion technology included the fusion of CT image, magnetic resonance image, and ultrasound image internally or externally. The application of image fusion technology had improved the identification accuracy of GFM and was helpful for the plan design of PCa radiotherapy. This article provided a systematic review of the application of fusion of various medical images in PCa IGRT in recent years. Among them, the application and result of image fusion technology in GFM identification and the impact on the plan design for PCa radiotherapy were emphasized. It hoped that this review could provide some theoretical reference for the deeper integration of image fusion technology with PCa IGRT.


Assuntos
Marcadores Fiduciais , Neoplasias da Próstata , Masculino , Humanos , Ouro , Neoplasias da Próstata/diagnóstico por imagem , Neoplasias da Próstata/radioterapia , Neoplasias da Próstata/patologia , Biomarcadores , Tecnologia
4.
Sensors (Basel) ; 22(23)2022 Dec 06.
Artigo em Inglês | MEDLINE | ID: mdl-36502247

RESUMO

With the rapid increase of smart Internet of Things (IoT) devices, edge networks generate a large number of computing tasks, which require edge-computing resource devices to complete the calculations. However, unreasonable edge-computing resource allocation suffers from high-power consumption and resource waste. Therefore, when user tasks are offloaded to the edge-computing system, reasonable resource allocation is an important issue. Thus, this paper proposes a digital-twin-(DT)-assisted edge-computing resource-allocation model and establishes a joint-optimization function of power consumption, delay, and unbalanced resource-allocation rate. Then, we develop a solution based on the improved whale optimization scheme. Specifically, we propose an improved whale optimization algorithm and design a greedy initialization strategy to improve the convergence speed for the DT-assisted edge-computing resource-allocation problem. Additionally, we redesign the whale search strategy to improve the allocation results. Several simulation experiments demonstrate that the improved whale optimization algorithm reduces the resource allocation and allocation objective function value, the power consumption, and the average resource allocation imbalance rate by 12.6%, 15.2%, and 15.6%, respectively. Overall, the power consumption with the assistance of the DT is reduced to 89.6% of the power required without DT assistance, thus, improving the efficiency of the edge-computing resource allocation.


Assuntos
Alocação de Recursos , Baleias , Animais , Algoritmos , Simulação por Computador , Internet
5.
Med Sci Monit ; 22: 969-76, 2016 Mar 24.
Artigo em Inglês | MEDLINE | ID: mdl-27009380

RESUMO

BACKGROUND: Risk of venous thromboembolism (VTE), including deep vein thrombosis (DVT) and pulmonary embolism (PE), may be increased in liver cirrhosis. We conducted a single-center study to explore the epidemiology, risk factors, and in-hospital mortality of VTE in Chinese patients with liver cirrhosis. MATERIAL/METHODS: All patients with liver cirrhosis who were consecutively admitted to our hospital between January 2011 and December 2013 were retrospectively included. RESULTS: Of 2006 patients with liver cirrhosis included, 9 patients were diagnosed with or developed VTE during hospitalization, including 5 patients with a previous history of DVT, 1 patient with either a previous history of DVT or new onset of PE, and 3 patients with new onset of VTE (PE, n=1; DVT, n=2). Risk factors for VTE included a significantly higher proportion of hypertension and significantly higher red blood cells, hemoglobin, alanine aminotransferase, aspartate aminotransferase, prothrombin time (PT), international normalized ratio (INR), D-dimer, and Child-Pugh scores. The in-hospital mortality was significantly higher in patients with VTE than those without VTE (33.3% [3/9] versus 3.4% [67/1997], P<0.001). CONCLUSIONS: VTE was observed in 0.4% of patients with liver cirrhosis during hospitalization and it significantly increased the in-hospital mortality. Elevated PT/INR aggravated the risk of VTE.


Assuntos
Mortalidade Hospitalar , Cirrose Hepática/mortalidade , Tromboembolia Venosa/mortalidade , Adulto , Idoso , Idoso de 80 Anos ou mais , China/epidemiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Estudos Retrospectivos , Fatores de Risco
6.
Med Sci Monit ; 22: 2528-50, 2016 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-27432511

RESUMO

BACKGROUND Portal venous system thrombosis (PVST) is a life-threatening complication of liver cirrhosis. We conducted a retrospective study to comprehensively analyze the prevalence and risk factors of PVST in liver cirrhosis. MATERIAL AND METHODS All cirrhotic patients without malignancy admitted between June 2012 and December 2013 were eligible if they underwent contrast-enhanced CT or MRI scans. Independent predictors of PVST in liver cirrhosis were calculated in multivariate analyses. Subgroup analyses were performed according to the severity of PVST (any PVST, main portal vein [MPV] thrombosis >50%, and clinically significant PVST) and splenectomy. Odds ratios (ORs) and 95% confidence intervals (CIs) were reported. RESULTS Overall, 113 cirrhotic patients were enrolled. The prevalence of PVST was 16.8% (19/113). Splenectomy (any PVST: OR=11.494, 95%CI=2.152-61.395; MPV thrombosis >50%: OR=29.987, 95%CI=3.247-276.949; clinically significant PVST: OR=40.415, 95%CI=3.895-419.295) and higher hemoglobin (any PVST: OR=0.974, 95%CI=0.953-0.996; MPV thrombosis >50%: OR=0.936, 95%CI=0.895-0.980; clinically significant PVST: OR=0.935, 95%CI=0.891-0.982) were the independent predictors of PVST. The prevalence of PVST was 13.3% (14/105) after excluding splenectomy. Higher hemoglobin was the only independent predictor of MPV thrombosis >50% (OR=0.952, 95%CI=0.909-0.997). No independent predictors of any PVST or clinically significant PVST were identified in multivariate analyses. Additionally, PVST patients who underwent splenectomy had a significantly higher proportion of clinically significant PVST but lower MELD score than those who did not undergo splenectomy. In all analyses, the in-hospital mortality was not significantly different between cirrhotic patient with and without PVST. CONCLUSIONS Splenectomy may increase by at least 10-fold the risk of PVST in liver cirrhosis independent of severity of liver dysfunction.


Assuntos
Cirrose Hepática/complicações , Esplenectomia/efeitos adversos , Trombose Venosa/etiologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Estudos de Coortes , Feminino , Mortalidade Hospitalar , Humanos , Cirrose Hepática/diagnóstico por imagem , Cirrose Hepática/patologia , Masculino , Pessoa de Meia-Idade , Veia Porta/patologia , Prevalência , Estudos Retrospectivos , Fatores de Risco , Trombose Venosa/diagnóstico por imagem , Trombose Venosa/patologia
7.
Anat Histol Embryol ; 53(1): e13008, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38230833

RESUMO

Telocytes (TCs) are distinctive interstitial cells due to their characteristic structures and heterogeneity. They are suggested to participate in tissue repair/regeneration. TCs have been identified in many organs of various mammals. However, data on TCs in lower animals are still very limited. In this work, TCs were identified in the myocardium of the bullfrog (Rana catesbeiana) by light and transmission electron microscopy (TEM). The structural relationships between TCs and neighbouring cell types were measured using the ImageJ (FiJi) morphometric software. TCs with slender Tps (telepodes) were located around cardiomyocytes (CMC). TEM revealed TCs with long Tps in the stroma between CMC. The homocellular tight junctions were observed between the Tps. The Tps were also very close to the neighbouring CMC. The distance between Tps and CMC was 0.15 ± 0.08 µm. Notably, Tps were observed to adhere to the periphery of the satellite cells. The Tps and the satellite cells established heterocellular structural connections by tight junctions. Additionally, Tps were frequently observed in close proximity to mast cells (MCs). The distance between the Tps and the MCs was 0.19 ± 0.09 µm. These results confirmed that TCs are present in the myocardium of the bullfrog, and that TCs established structural relationships with neighbouring cell types, including satellite cells and MCs. These findings provide the anatomical evidence to support the note that TCs are involved in tissue regeneration.


Assuntos
Miócitos Cardíacos , Telócitos , Animais , Rana catesbeiana , Miocárdio , Telócitos/ultraestrutura , Microscopia Eletrônica de Transmissão/veterinária , Mamíferos
8.
Front Plant Sci ; 14: 1203881, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37384361

RESUMO

Introduction: Moso bamboo is one of the important clonal plants with complex underground rhizome-root system. Ramets connected by rhizome can translocate and share nitrogen (N), which may affect the nitrogen use efficiency (NUE) of moso bamboo. The aims of this study were to investigate the mechanisms of N physiological integration and its relationship with NUE of moso bamboo. Methods: A pot experiment was conducted to trace the movement of 15N between the connected ramets of moso bamboo in both homogeneous and heterogeneous N environments. Results: Results showed that N translocation within clonal fragments of moso bamboo was detected in both homogeneous and heterogeneous environments. The intensity of physiological integration (IPI) was significantly lower in homogeneous environments than that in heterogeneous environments. 15N translocation between the connected ramtes of moso bamboo was determined by the source-sink relationship in heterogeneous environments, and the 15N allocation of the fertilized ramet was higher than that of the connected unfertilized ramet. The NUE of connected treatment was significantly higher than that of severed treatment, which suggested that physiological integration significantly improved the NUE of moso bamboo. In addition, the NUE of moso bamboo was significantly higher in heterogeneous environments than that in homogeneous environments. The contribution rate of physiological integration (CPI) on NUE in heterogeneous environments was significantly higher than that in homogenous environments. Discussion: These results will provide theoretical basis for precision fertilization in moso bamboo forests.

9.
J Colloid Interface Sci ; 630(Pt B): 37-46, 2023 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-36327737

RESUMO

In this work, we report a novel MoSx/Mn0.3Cd0.7S composite catalyst that has been designed and fabricated by in situ coupling MoSx nanoclusters with 1D Mn0.3Cd0.7S nanorods for photocatalytic H2 production. The catalyst features a 1D nanostructure with MoSx nanoclusters uniformly dispersed along the Mn0.3Cd0.7S nanorod. It was found that an intimate interface is built between MoSx nanoclusters and Mn0.3Cd0.7S nanorods thanks to the facile in situ photoreduction route, which contributes to a high-efficiency interfacial charge separation. The resulting MoSx/Mn0.3Cd0.7S photocatalyst shows a dramatically enhanced visible-light-driven photocatalytic H2 production activity compared with the control samples, owing to more efficient spatial charge separation as well as enriched active sites. This work is expected to provide an optimized structure model for rational design and constructing novel, inexpensive, efficient and stable cocatalyst/metal sulfide photocatalyst systems for H2 production.

10.
iScience ; 26(7): 106980, 2023 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-37332676

RESUMO

Herein, we report choline chloride-based deep eutectic solvents (DESs) promoted conversion of N-acetyl-d-glucosamine (GlcNAc) into nitrogen-containing compounds, i.e., 3-acetamido-5-(1',2'-dihydroxyethyl) furan (Chromogen III) and 3-acetamido-5-acetylfuran (3A5AF). The binary deep eutectic solvent choline chloride-glycerin (ChCl-Gly), was found to promote the dehydration of GlcNAc to form Chromogen III, which reaches a maximum yield of 31.1%. On the other hand, the ternary deep eutectic solvent, choline chloride-glycerol-B(OH)3 (ChCl-Gly-B(OH)3), promoted the further dehydration of GlcNAc into 3A5AF with a maximum yield of 39.2%. In addition, the reaction intermediate, 2-acetamido-2,3-dideoxy-d-erythro-hex-2-enofuranose (Chromogen I), was detected by in situ nuclear magnetic resonance (NMR) techniques when promoted by ChCl-Gly-B(OH)3. The experimental results of the 1H NMR chemical shift titration showed ChCl-Gly interactions with α-OH-3 and α-OH-4 of GlcNAc, which is responsible for promoting the dehydration reaction. Meanwhile, the strong interaction between Cl- and GlcNAc was demonstrated by 35Cl NMR.

11.
Ecol Evol ; 13(7): e10250, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37415642

RESUMO

Whereas the presence of flowers on ornamental flowering plants is essential for their identification via traditional methods, ornamental flowering plants cannot be reliably identified in non-flowering stages likewise. Here, DBALM (DNA Barcodes-Leaf Morphology), a new approach that combines DNA barcoding data with micromorphological features of the leaf epidermis and that is not limited by the flowering stage, was used to identify 16 evergreen rhododendron cultivars. First, the sequences of DNA barcodes, ITS, matK, psbA-trnH, and rbcL, were obtained from the DNA of leaves. Phylogenetic analysis was conducted to clarify the groupings among all the samples based on the four markers. Then, microscopic features of the leaf epidermis were used to further distinguish individuals from the same clade. DNA barcoding permitted the 16 cultivars to be divided into eight groups. The microscopic features of the leaf epidermis permitted cultivars within the same clade to be distinguished. The matK + psbA-trnH combination was the most effective barcode combination in this study. In addition, the new primer matK-Rh_R was designed, and it increased the amplification rate of evergreen rhododendron cultivars to 100%. In sum, DBALM was capable of accurately identifying the 16 evergreen rhododendron cultivars using data collected from a single leaf in the vegetative growth stage. This method can greatly facilitate the identification and breeding of ornamental flowering plants.

12.
Sci Rep ; 12(1): 6661, 2022 04 22.
Artigo em Inglês | MEDLINE | ID: mdl-35459798

RESUMO

The objectives of this study were to investigate the allelopathic effects of sesame extracts of on seed germination of moso bamboo, and to isolate and identify the potential allelochemicals. A factorial design with three organs (root, stem and leaf) and five concentrations (0, 25, 50, 75 and 100 mg mL-1) was carried out. Seeds of moso bamboo were soaked in sesame extracts to investigate their germination and growth. The allelochemicals were isolated and identified using the high performance liquid chromatograph (HPLC) system. The germination indices of the same organ decreased with the increase of extract concentrations, while the mean germination time increased, picking at the concentration of 100 mg mL-1. The radicle length and plumule length decreased, while the ratio of radicle length to plumule length increased. The allelopathy inhibition effect increased with the increase of extract concentrations, and it was significantly higher at the concentration of 100 mg mL-1 than that of 25 mg mL-1. The synthesis effect increased with the increase of extract concentrations, and it was significantly higher in leaf than root and stem. Chemical analyses identified 9 allelochemicals species (mostly phenolics and alkaloids) in the aqueous extracts. These results indicated that aqueous extracts of sesame caused the delay in seed germination and growth of moso bamboo, and phenolics and alkaloids in the aqueous extracts maybe the major reasons for the observed inhibition effects of sesame.


Assuntos
Alelopatia , Sesamum , Germinação , Feromônios/farmacologia , Extratos Vegetais/farmacologia , Poaceae , Sementes
13.
Food Chem X ; 16: 100505, 2022 Dec 30.
Artigo em Inglês | MEDLINE | ID: mdl-36519103

RESUMO

The adsorption/desorption process of flavonoids obtained from bamboo shoots residues of Phyllostachys edulis (RPEFs) was established by resin screening, adsorption isotherms, adsorption kinetics and dynamic tests. Results indicated the Langmuir equation fairly fitted the isotherms data and the pseudo-second-order model accurately described its kinetic adsorption on HPD-500 resin. The optimal process was as follows: 2 mg/mL of solution, 2.8 BV feed volume under 2 BV/h flow rate for adsorption; 5 BV volume of 70 % ethanol with a flow rate of 2 BV/h for desorption. After enrichment, the flavonoids in RPEFs increased from 1.39 % to 37.34 %. The analysis of UPLC-TOF-MS/MS uncovered that the purified RPEFs were composed of four major flavonoids. It had potent hypoglycemic activity via PI3K/AKT pathway by upregulating the protein expression of PI3K, AKT, IRS-1, and GLUT4 in a dose-dependent manner based on HepG2-IR cells. Those results provide possible utilization of Phyllostachys edulis by-products in food additives.

14.
PLoS One ; 17(11): e0277778, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36417395

RESUMO

A major challenge in extracting high-quality DNA from bryophytes is the treatment of bryophyte material in the field. The existing and commonly used treatment methods in the field have several shortcomings. Natural drying methods can lead to DNA breaks. In addition, it is highly cumbersome to carry large quantities of silica gel in the field due to its weight and high risk of contamination among samples. In this study, we explored more convenient drying methods to treat bryophyte specimens and promote more efficient DNA recovery. The quantity and quality of genomic DNA extracted from every bryophyte species using different drying methods, including hot-air drying methods (150°C, 80°C, and 40°C), natural drying method, and silica gel drying method, were measured. Spectrophotometry, electrophoresis, and PCR amplification were performed to assess the effects of different drying methods. The results of total DNA purity, total DNA concentration, PCR success, and OD 260/230 ratios suggested that the hot-air drying (40-80°C) was the best method. The morphological comparison revealed that hot-air drying at 40°C and 80°C exerted no significant adverse effects on plant morphology and taxonomic studies. Thus, this method prevents rapid DNA degradation and silica gel pollution and saves the workforce from carrying large amounts of silica gel to the field. Several inexpensive devices, such as portable hairdryers, fan heaters, and electric blankets, are available that can be easily carried to the field for drying molecular specimens.


Assuntos
Briófitas , Sílica Gel , Briófitas/genética , Dessecação/métodos , Reação em Cadeia da Polimerase , DNA
15.
Sci Rep ; 12(1): 16392, 2022 09 30.
Artigo em Inglês | MEDLINE | ID: mdl-36180535

RESUMO

Bamboo-fungus agroforestry management is an ecological model of sustainable production of moso bamboo forest, and Stropharia rugosoannulata has been widely planted in moso bamboo forest. However, little attention has been paid to soil fauna community in bamboo-fungus agroforestry system. Thus, the aim of this study was to investigate the response of soil fauna communities to agroforestry management, and to explore the relationships between soil fauna communities and soil properties. An experiment with 0, 1, 2 and 3 years of planting was carried out in an existing moso bamboo forest. The community composition of soil meso- and micro-fauna was investigated, and the soil properties were determined. Results showed that a total of 2968 individuals of soil meso- and micro-fauna, belonging to 8 classes and 13 groups were detected. The group number and density of soil fauna was highest right and then decreased. Planting Stropharia rugosoannulata in moso bamboo forest increased the density of dominant groups, but did not change its composition. Shannon-Weiner diversity index (H), Margalef richness index (D) and Density-Group diversity index (DG) were the highest one year after planting the fungus, while Simpson dominance index (C) was the lowest in the meantime. Contents of soil moisture (SMC), organic matter (SOM), total nitrogen (TN), total phosphorus (TP) and total potassium (TK) increased first and then decreased with the increase of planting years, peaking at 1 year after planting, while the pH value continued to increase. Responses of soil fauna community were associated with soil physicochemical properties. Redundancy analysis (RDA) showed that SOM was the main environmental factor driving the variation of soil fauna community, followed by TP and TN. In conclusion, planting Stropharia rugosoannulata in moso bamboo increased the diversity and abundance of soil fauna communities due to its contribution to abundance of organic matter and supply of nutrients.


Assuntos
Agaricales , Solo , China , Florestas , Humanos , Nitrogênio , Fósforo , Plantas , Poaceae , Potássio , Microbiologia do Solo
16.
PhytoKeys ; 183: 9-19, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34720627

RESUMO

Haplodontiumaltunense X.R.Wang & S.Mamtimin, a new moss species of the family Bryaceae from Xinjiang Uygur Autonomous Region, China is described and illustrated. Genetic analysis based on ITS sequences shows that this species is a member of the Bryaceae and in the same clade as Anomobryum. Particularly distinctive features of the new species include: double peristome; the exostome has raised and membranous chomata with united lamellae between two teeth proximally; the endostome is poorly developed and all the endostomial material tightly adherent to the exostome.

17.
Mitochondrial DNA B Resour ; 6(3): 837-839, 2021 Mar 11.
Artigo em Inglês | MEDLINE | ID: mdl-33763597

RESUMO

Mnium is the type genus of the family Mniaceae, the species' richest family of order Bryales (Bryophyte). Mnium marginatum is widely distributed worldwide. The complete chloroplast genome of M. marginatum was sequenced by high-throughput sequencing technology. The chloroplast genome is 124,935 bp in length with a quadripartite structure. The two inverted repeat regions are 9,910 bp long and separated by a large single-copy region of 86,572 bp and a small single-copy region of 18,543 bp. Based on the chloroplast genome data of 11 bryophytes downloaded from GenBank and one acquired in this study, phylogenetic trees were constructed.

18.
Mitochondrial DNA B Resour ; 6(9): 2632-2634, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34409162

RESUMO

Rhodobryum laxelimbatum (Bryophyta, Bryaceae) is one of the folk medicine resources in Southwest China, which has excellent potential for application in treating cardiovascular diseases. In this study, R. laxelimbatum was sequenced by high-throughput sequencing technology. The complete chloroplast genome is 124,632 bp in length with a quadripartite structure. Two inverted repeat regions are 9837 bp, separated by a large single copy region of 86,444 bp and a small single copy region of 18,514 bp. It encodes 118 unique genes, including 82 protein-coding genes, 32 tRNA genes, and four rRNA genes. The phylogenetic tree was constructed based on the complete chloroplast genome sequences of 18 bryophytes, downloaded from GenBank and acquired in this study. The phylogenetic analysis strongly indicated that R. laxelimbatum was the sister group of the clade which consists of Mnium marginatum, Pohlia cruda and Pohlia nutans. The R. laxelimbatum chloroplast genome sequence provides new genomic resources, which will improve its research, conservation, and application in the future.

19.
Ecol Evol ; 11(12): 7448-7460, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-34188826

RESUMO

The utility of elevational gradients as tools to test either ecological hypotheses and delineate elevation-associated environmental factors that explain the species diversity patterns is critical for moss species conservation. We examined the elevational patterns of species richness and evaluated the effects of spatial and environmental factors on moss species predicted a priori by alternative hypotheses, including mid-domain effect (MDE), habitat complexity, energy, and environment proposed to explain the variation of diversity. Last, we assessed the contribution of elevation toward explaining the heterogeneity among sampling sites. We observed the hump-shaped distribution pattern of species richness along elevational gradient. The MDE and the habitat complexity hypothesis were supported with MDE being the primary driver for richness patterns, whereas little support was found for the energy and the environmental factors.

20.
Molecules ; 14(6): 2195-201, 2009 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-19553892

RESUMO

A total of 38 volatile components were identified in Rhodobryum giganteum (Schwaegr.) Par. collected from two different geographic regions by headspace solid-phase microextraction (HS-SPME), combined with gas chromatography/mass spectrometry (GC/MS). The volatile components included some aliphatic and aromatic aldehydes, monoterpene hydrocarbons and a sesquiterpene (alpha-farnesene), with 1-methoxy-2-propyl acetate and n-hexanal being found to be the most abundant volatile components. Analysis of the chemical constituents in the volatile oil of the two samples showed that ten compounds were shared.


Assuntos
Briófitas/química , Cromatografia Gasosa-Espectrometria de Massas/métodos , Microextração em Fase Sólida/métodos , Compostos Orgânicos Voláteis/química , Aldeídos/química , Aldeídos/isolamento & purificação , Monoterpenos/química , Monoterpenos/isolamento & purificação , Sesquiterpenos/química , Sesquiterpenos/isolamento & purificação , Compostos Orgânicos Voláteis/isolamento & purificação
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA