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1.
Zhongguo Zhong Yao Za Zhi ; 48(7): 1892-1898, 2023 Apr.
Artigo em Chinês | MEDLINE | ID: mdl-37282965

RESUMO

The present study aimed to explore the chemical constituents from the stems and leaves of Cephalotaxus fortunei. Seven lignans were isolated from the 75% ethanol extract of C. fortunei by various chromatographic methods, including silica gel, ODS column chromatography, and HPLC. The structures of the isolated compounds were elucidated according to physicochemical properties and spectral data. Compound 1 is a new lignan named cephalignan A. The known compounds were identified as 8-hydroxy-conidendrine(2), isolariciresinol(3), leptolepisol D(4), diarctigenin(5), dihydrodehydrodiconiferyl alcohol 9'-O-ß-D-glucopyranoside(6), and dihydrodehydrodiconiferyl alcohol 4-O-ß-D-glucopyranoside(7). Compounds 2 and 5 were isolated from the Cephalotaxus plant for the first time.


Assuntos
Cephalotaxus , Lignanas , Lignanas/análise , Folhas de Planta/química , Etanol , Cromatografia Líquida de Alta Pressão
2.
J Fluoresc ; 31(1): 29-38, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33048296

RESUMO

Firstly, a novel pyrazole-pyrazoline fluorescent probe was developed and synthesized. The probe can be used to determine Fe3+ ions in a series of cations in tetrahydrofuran aqueous solution with high selectivity and high sensitivity. After the addition of iron ions, the fluorescence intensity is significantly reduced, Its structure was characterized by 1H NMR, 13C NMR and HR-ESI-MS. UV absorption spectra and Fluorescence spectroscopy were used to study the selective recognition of probe M on metal ions. The probe M can selectivity and sensitivity to distinguish the target ion from other ions through different fluorescence phenomena. In addition, the binding modes of M with Fe3+ were proved to be 1:1 stoichiometry in the complexes by Job's plot, IR results. The combination of probe M and iron ions is 1:1, and the detection limit is 3.9 × 10-10 M. The binding mode and sensing mechanism of M with Fe3+ was verified by theoretical calculations using Gaussian 09 based on B3LYP/6-31G(d) basis.

3.
Cell Rep ; 33(11): 108495, 2020 12 15.
Artigo em Inglês | MEDLINE | ID: mdl-33326788

RESUMO

Neurogenesis in the developing neocortex relies on extensive mitosis of radial glial cells (RGCs) in the apical surface. The nuclear migration of epithelial-like RGCs is fundamentally important for proper mitosis, but how the apical processes of RGCs are anchored to ensure the nucleokinetic behavior of RGCs remains unclear. Here we find that Talpid3, related to Joubert syndrome, is localized to the mother centriole of RGCs and is required for their apical mitosis. Genetic silencing of Talpid3 causes abnormal RGC delamination and thereby impairs their interkinetic nuclear migration in both cell-autonomous and non-autonomous manners. Further analyses reveal that Talpid3 associates with Ninein to regulate microtubule organization and maintain the integrity of adherens junctions to anchor RGCs. Moreover, genetic ablation of Talpid3 results in synchronized, ectopic mitosis of neural progenitors and dysregulated neurogenesis. Our study provides an intriguing perspective for the non-ciliogenic role of centriolar proteins in mediating cortical neurogenesis.


Assuntos
Proteínas de Ciclo Celular/metabolismo , Centrossomo/metabolismo , Neurogênese/imunologia , Junções Aderentes/metabolismo , Animais , Humanos , Camundongos
4.
Curr Pharm Des ; 23(39): 5973-5982, 2018 02 12.
Artigo em Inglês | MEDLINE | ID: mdl-28714412

RESUMO

MicroRNAs are small non-coding RNAs with regulatory biological activity, by modulating target genes on epigenetic, transcriptional, post-transciptional and translational levels. Hundreds of reports indicated that miRNAs play important roles in non-small cell lung cancer (NSCLC). Actually, microRNAs are both regulation targets and regulators targeting effector genes. This article reviewed multifaceted role of microRNAs associated to NSCLC, not only targeting to but also targeted by tumor related genes, to help us understand microRNAs related complex regulation networks. Aberrant expressed micoRNAs and their targets were summarized; the statistical results showed that several microRNAs may play key roles by targeting multiple tumor associated targets. On the other hand, Oncogenes and tumor repressors represented by PTEN were also shown to be the most popular targets of microRNAs. Additionally, ZEB1/2 may be a featured pathway in NSCLC, with significant frequency modulated by microRNAs.


Assuntos
Antineoplásicos/farmacologia , Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Neoplasias Pulmonares/tratamento farmacológico , MicroRNAs/metabolismo , Animais , Carcinoma Pulmonar de Células não Pequenas/metabolismo , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Regulação Neoplásica da Expressão Gênica/genética , Humanos , Neoplasias Pulmonares/metabolismo , MicroRNAs/genética
5.
J Mol Graph Model ; 72: 178-186, 2017 03.
Artigo em Inglês | MEDLINE | ID: mdl-28107751

RESUMO

To develop more potent JAK3 kinase inhibitors, a series of CP-690550 derivatives were investigated using combined molecular modeling techniques, such as 3D-QSAR, molecular docking and molecular dynamics (MD). The leave-one-out correlation (q2) and non-cross-validated correlation coefficient (r2) of the best CoMFA model are 0.715 and 0.992, respectively. The q2 and r2 values of the best CoMSIA model are 0.739 and 0.995, respectively. The steric, electrostatic, and hydrophobic fields played important roles in determining the inhibitory activity of CP-690550 derivatives. Some new JAK3 kinase inhibitors were designed. Some of them have better inhibitory activity than the most potent Tofacitinib (CP-690550). Molecular docking was used to identify some key amino acid residues at the active site of JAK3 protein. 10ns MD simulations were successfully performed to confirm the detailed binding mode and validate the rationality of docking results. The calculation of the binding free energies by MMPBSA method gives a good correlation with the predicted biological activity. To our knowledge, this is the first report on MD simulations and free energy calculations for this series of compounds. The combination results of this study will be valuable for the development of potent and novel JAK3 kinase inhibitors.


Assuntos
Janus Quinase 3/antagonistas & inibidores , Simulação de Acoplamento Molecular , Simulação de Dinâmica Molecular , Piperidinas/química , Inibidores de Proteínas Quinases/química , Pirimidinas/química , Pirróis/química , Relação Quantitativa Estrutura-Atividade , Sítios de Ligação , Interações Hidrofóbicas e Hidrofílicas , Concentração Inibidora 50 , Janus Quinase 3/química , Termodinâmica
6.
Appl Biochem Biotechnol ; 182(2): 755-768, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-27981427

RESUMO

Polyhydroxyalkanoates (PHAs) are promising alternatives to plastics since they have similar properties to polyolefin but are biodegradable and biocompatible. Recently, the conversion of propionate wastewater to PHAs by undefined mixed microbial cultures becomes attractive. However, how microbial community changes remains unclear during the enrichment step, which is critical for a robust PHA-producing system. In this study, PHA-accumulating cultures were enriched under feast/famine condition using propionate-rich substrates. Our results showed that during the first 2 h of the enrichment, dissolved oxygen of cultures increased remarkably until saturation, and amounts of C, N, and chemical oxygen demand of cultures decreased significantly to a very low level. High-throughput sequencing revealed that bacterial populations affiliated with Alphaproteobacteria and Bacteroidetes dominated the cultures enriched. Most of these dominant populations contributed to the conversion of short-chain fatty acids to PHAs. Being fed with the substrate rich in propionate but without nitrogen, the cultures enriched could accumulate nearly 27% PHAs at 72 h with higher content of hydroxyvalerate. Our work reveals the process in which environmental microbes responded to propionate-rich condition and shifted to populations for accumulating PHAs; it also will be helpful to develop an efficient PHA-producing system using propionate-rich waste.


Assuntos
Alphaproteobacteria/crescimento & desenvolvimento , Bacteroidetes/crescimento & desenvolvimento , Consórcios Microbianos/fisiologia , Poli-Hidroxialcanoatos/biossíntese , Propionatos/metabolismo , Águas Residuárias/microbiologia , Eliminação de Resíduos de Serviços de Saúde/métodos
7.
BMC Infect Dis ; 16(1): 516, 2016 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-27670780

RESUMO

BACKGROUND: The spread of multidrug-resistant tuberculosis (MDR-TB) Mycobacterium tuberculosis (M. tuberculosis) strains has been a big challenge to the TB control and prevention in China. Knowledge about patterns of drug resistance in TB high-burden areas of China is crucial to develop appropriate control strategies. We conducted a comprehensive investigation of the resistance pattern of M. tuberculosis in Heilongjiang Province. METHODS: 1427 M. tuberculosis clinical strains were isolated from pulmonary TB patients hospitalized between 2007 and 2012. The susceptibility of the isolates to the first-line anti-TB drugs and the resistance of MDR M. tuberculosis to fluoroquinolones were examined. We also performed a statistical analysis to identify the correlated risk factors for high burden of MDR-TB. RESULTS: The global resistance rates of 2007-2012 to the first-line drugs and MDR were 57.0 and 22.8 %, respectively. Notably, the primary MDR-TB and pan-resistance rates were as high as 13.6 and 5.0 %, respectively. Of MDR M. tuberculosis isolates (2009), approximately 13 % were not susceptible to any of the fluoroquinolones tested. Being age of 35 to 54, high re-treatment proportion, the presence of cavity lesion, and high proportion of shorter hospitalization are correlated with the development of MDR-TB. CONCLUSIONS: The high prevalence of drug resistant, MDR-TB, and fluoroquinolone-resistant MDR-TB is a big concern for TB control. More importantly, in order to control the development of MDR-TB effectively, we need to pay more attention to the primary resistance. Targeting reducing the prevalence of the risk factors may lead to better TB control in China.

8.
Microb Cell Fact ; 15(1): 101, 2016 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-27287016

RESUMO

BACKGROUND: The cell growth and ethanol yield of Zymomonas mobilis may be detrimentally affected by salt stress frequently present in some biomass-based fermentation systems, leading to a decrease in the rate of sugar conversion to ethanol or other bioproducts. To address this problem, improving the salt tolerance of Z. mobilis is a desirable way. However, limited progress has been made in development of Z. mobilis with higher salt tolerance for some technical challenges in the past decades. Recently, transposon insertion mutant system has been widely used as a novel genetic tool in many organisms to develop mutant strains. In this study, Tn5-based transposon insertion mutagenesis system firstly used for construction of higher salt tolerance strain in Z. mobilis. RESULTS: Approximately 200 Z. mobilis ZM4 mutants were generated by using Tn5-based transposon mutagenesis system. The mutant strain ZMT2 with improved salt tolerance phenotype was obtained by screening on RM agar plates with additional 1 % NaCl. Strain ZMT2 was confirmed to exhibit better fermentation performance under NaCl stress than wild type of strain ZM4. The transposon insertion was located in ZMO1122 (himA) by genome walking. Discruption of himA gene showed that himA may play an important role in response to salt tolerance in Z. mobils. CONCLUSIONS: The mutant strain ZMT2 with a transposon insertion in himA gene of the genome showed obviously higher sugar conversion rate to ethonal under up to 2 % NaCl stress than did the wild ZM4 strain. Besides, ZMT2 exhibited shared fermentative capabilities with wild ZM4 strain under no or low NaCl stress. This report firstly showed that himA played a role in responding to NaCl stress. Furthermore, the result indicated that Tn5-based transposon mutagenesis system was a feasible tool not only for genetic engineering in Z. mobilis strain improvement, but also in tapping resistent genes.


Assuntos
Tolerância ao Sal/genética , Transposases/genética , Zymomonas/genética , Zymomonas/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Etanol/metabolismo , Engenharia Genética , Glucose/metabolismo , Mutagênese Insercional , NAD/metabolismo , Fenótipo , Reação em Cadeia da Polimerase em Tempo Real , Transposases/metabolismo , Zymomonas/crescimento & desenvolvimento
9.
J Biotechnol ; 220: 88-9, 2016 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-26806488

RESUMO

The type strain Lentibacillus amyloliquefaciens LAM0015(T) with considerably highly NaCl tolerance is a member of halophiles. Here we report its genome sequence, the first to publish complete genome sequence of the Lentibacillus genus. It contains 3,858,520bp with an average GC content of 42.12%, encoding multiple valuable proteins academically and industrially. The genome sequence of strain LAM0015(T) provides basic information for further elucidation of halophilic mechanism and wider exploitation of functional genes.


Assuntos
Bacillaceae/genética , Genoma Bacteriano , Bacillaceae/isolamento & purificação , Bacillaceae/fisiologia , Composição de Bases , Sequência de Bases , China , Mapeamento Cromossômico , DNA Bacteriano/genética , Tamanho do Genoma , Microbiologia Industrial , Dados de Sequência Molecular , RNA Bacteriano/genética , Cloreto de Sódio , Microbiologia do Solo
10.
Antonie Van Leeuwenhoek ; 109(2): 171-8, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26545789

RESUMO

A Gram-stain positive, non-motile, non-sporogenous, aerobic, rod-shaped and halophilic bacterium, designated LAM0015(T), was isolated from a saline sediment sample collected from Yantai City in China. The isolate was found to be able to grow at NaCl concentrations of 5-25 % (w/v) (optimum: 7-12 %), 15-45 °C (optimum: 35 °C) and pH 5.0-9.0 (optimum: 7.0). The major fatty acids were determined to be anteiso-C15:0 and anteiso-C17:0. The predominant respiratory quinone was identified as MK-7. The cell wall peptidoglycan was determined to contain meso-diaminopimelic acid. The polar lipids were found to be diphosphatidyglycerol, phosphatidylglycerol, five phospholipids and one glycolipid. The DNA G+C content was 43.1 mol% as determined by the T m method. Analysis of the 16S rRNA gene sequence indicated that the isolate belongs within the genus Lentibacillus and is closely related to Lentibacillus persicus DSM 22530(T), Lentibacillus salicampi JCM 11462(T) and Lentibacillus jeotgali JCM 15795(T) with 97.3, 96.7 and 96.4 % sequence similarity, respectively. The DNA-DNA hybridization value between LAM0015(T) and L. persicus DSM 22530(T) was 51.2 ± 1.4 %. Based on its phenotypic, phylogenetic and chemotaxonomic characteristics, strain LAM0015(T) is concluded to represent a novel species of the genus Lentibacillus, for which the name Lentibacillus amyloliquefaciens sp. nov. is proposed. The type strain is LAM0015(T) (=ACCC 06401(T) = JCM 19838(T)).


Assuntos
Bacillaceae/isolamento & purificação , Sedimentos Geológicos/microbiologia , Cloreto de Sódio/metabolismo , Bacillaceae/classificação , Bacillaceae/genética , Bacillaceae/metabolismo , Composição de Bases , China , DNA Bacteriano/genética , Ácidos Graxos/química , Ácidos Graxos/metabolismo , Sedimentos Geológicos/análise , Dados de Sequência Molecular , Filogenia , RNA Ribossômico 16S/genética , Cloreto de Sódio/análise
11.
Appl Microbiol Biotechnol ; 99(13): 5739-48, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-25935346

RESUMO

Furfural and acetic acid from lignocellulosic hydrolysates are the prevalent inhibitors to Zymomonas mobilis during cellulosic ethanol production. Developing a strain tolerant to furfural or acetic acid inhibitors is difficul by using rational engineering strategies due to poor understanding of their underlying molecular mechanisms. In this study, strategy of adaptive laboratory evolution (ALE) was used for development of a furfural and acetic acid-tolerant strain. After three round evolution, four evolved mutants (ZMA7-2, ZMA7-3, ZMF3-2, and ZMF3-3) that showed higher growth capacity were successfully obtained via ALE method. Based on the results of profiling of cell growth, glucose utilization, ethanol yield, and activity of key enzymes, two desired strains, ZMA7-2 and ZMF3-3, were achieved, which showed higher tolerance under 7 g/l acetic acid and 3 g/l furfural stress condition. Especially, it is the first report of Z. mobilis strain that could tolerate higher furfural. The best strain, Z. mobilis ZMF3-3, has showed 94.84% theoretical ethanol yield under 3-g/l furfural stress condition, and the theoretical ethanol yield of ZM4 is only 9.89%. Our study also demonstrated that ALE method might also be used as a powerful metabolic engineering tool for metabolic engineering in Z. mobilis. Furthermore, the two best strains could be used as novel host for further metabolic engineering in cellulosic ethanol or future biorefinery. Importantly, the two strains may also be used as novel-tolerant model organisms for the genetic mechanism on the "omics" level, which will provide some useful information for inverse metabolic engineering.


Assuntos
Ácido Acético/metabolismo , Adaptação Biológica , Tolerância a Medicamentos , Etanol/metabolismo , Furaldeído/metabolismo , Zymomonas/genética , Zymomonas/metabolismo , Antibacterianos/metabolismo , Lignina/metabolismo , Engenharia Metabólica , Zymomonas/efeitos dos fármacos
12.
Appl Microbiol Biotechnol ; 99(12): 5363-71, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25895089

RESUMO

Furfural from lignocellulosic hydrolysates is the key inhibitor for bio-ethanol fermentation. In this study, we report a strategy of improving the furfural tolerance in Zymomonas mobilis on the transcriptional level by engineering its global transcription sigma factor (σ(70), RpoD) protein. Three furfural tolerance RpoD mutants (ZM4-MF1, ZM4-MF2, and ZM4-MF3) were identified from error-prone PCR libraries. The best furfural-tolerance strain ZM4-MF2 reached to the maximal cell density (OD600) about 2.0 after approximately 30 h, while control strain ZM4-rpoD reached its highest cell density of about 1.3 under the same conditions. ZM4-MF2 also consumed glucose faster and yield higher ethanol; expression levels and key Entner-Doudoroff (ED) pathway enzymatic activities were also compared to control strain under furfural stress condition. Our results suggest that global transcription machinery engineering could potentially be used to improve stress tolerance and ethanol production in Z. mobilis.


Assuntos
Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Furaldeído/metabolismo , Fator sigma/genética , Fator sigma/metabolismo , Zymomonas/metabolismo , Fermentação , Engenharia Genética , Zymomonas/genética
13.
Rheumatol Int ; 35(6): 963-71, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25377645

RESUMO

Previous studies have showed that patients with gout showed lower serum 25(OH)D levels. As the specific receptor of vitamin D, VDR plays an important role in regulating immune system by combining with vitamin D. In this study, we investigated whether the functional VDR polymorphisms were associated with susceptibility to gout in Chinese Han male population. A total of 504 patients with gout and 523 gout-free controls were recruited from the Affiliated Hospital of the Medical College, Qingdao University. Genotyping of VDR rs11568820, rs2228570 and rs1544410 was performed by TaqMan allele discrimination assays. An association analysis was carried out using the χ(2) test. A genotype-phenotype analysis was also conducted. Our results showed that polymorphisms of rs11568820 and rs1544410 in VDR were associated with gout in Chinese Han male population. The A allele of both rs11568820 and rs1544410 was associated with the risk of gout [P = 0.012 OR 1.251, 95% CI (1.051-1.490); P = 0.006, OR 1.574, 95% CI (1.139-2.175)]. However, there was no statistic significance between rs2228570 and gout (P = 0.186). Our study suggested that the polymorphisms of VDR may be relevant host susceptibility factors for the development of gout in Chinese Han male population. However, further study should be done in a larger size sample and other ethic to test and verify our result.


Assuntos
Povo Asiático/genética , Gota/genética , Polimorfismo Genético , Receptores de Calcitriol/genética , Adulto , Idoso , Estudos de Casos e Controles , Distribuição de Qui-Quadrado , China , Frequência do Gene , Estudos de Associação Genética , Predisposição Genética para Doença , Gota/diagnóstico , Gota/etnologia , Humanos , Masculino , Pessoa de Meia-Idade , Razão de Chances , Fenótipo , Fatores de Risco , Fatores Sexuais
14.
Guang Pu Xue Yu Guang Pu Fen Xi ; 34(9): 2351-4, 2014 Sep.
Artigo em Chinês | MEDLINE | ID: mdl-25532324

RESUMO

In the present paper, we propose a novel night visibility inversion algorithm. The key idea is based on the curve evolution theory in the context of dual light sources. First, we describe the features of the dual light sources night visibility inversion method, and explain the relationship between fluctuation of light source intensity and curve evolution with the special characters. Then, level set method is introduced ito define the light source intensity and establish the model with visibility inversion, and the algorithm formula is detailed. Experiments results show that, the algorithm is characterized with a strong robustness and compared with the standard visibility, the correlation of visibility result reaches up to 0.98 in the range of 2,000 meter to 12,000 me- ter, which can be used in the visibility monitoring with a large range, high precision and strong robustness.

15.
Biotechnol Biofuels ; 7: 101, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25024744

RESUMO

Biosynthesis of liquid fuels and biomass-based building block chemicals from microorganisms have been regarded as a competitive alternative route to traditional. Zymomonas mobilis possesses a number of desirable characteristics for its special Entner-Doudoroff pathway, which makes it an ideal platform for both metabolic engineering and commercial-scale production of desirable bio-products as the same as Escherichia coli and Saccharomyces cerevisiae based on consideration of future biomass biorefinery. Z. mobilis has been studied extensively on both fundamental and applied level, which will provide a basis for industrial biotechnology in the future. Furthermore, metabolic engineering of Z. mobilis for enhancing bio-ethanol production from biomass resources has been significantly promoted by different methods (i.e. mutagenesis, adaptive laboratory evolution, specific gene knock-out, and metabolic engineering). In addition, the feasibility of representative metabolites, i.e. sorbitol, bionic acid, levan, succinic acid, isobutanol, and isobutanol produced by Z. mobilis and the strategies for strain improvements are also discussed or highlighted in this paper. Moreover, this review will present some guidelines for future developments in the bio-based chemical production using Z. mobilis as a novel industrial platform for future biofineries.

16.
Carbohydr Polym ; 111: 645-54, 2014 Oct 13.
Artigo em Inglês | MEDLINE | ID: mdl-25037399

RESUMO

Bamboo is perennial woody grass, which distributed widely in the world and belonged to the Gramineae family and Bambuseae subfamily. It may be consider as a candidate lignocellulosic substrate for bio-ethanol production for its environmental benefits and higher annual biomass yield. The conversion of bamboo into bio-ethanol, bio-methane, natural food, flavonoids, and functional xylo-oligosaccharides production were reviewed in this paper. Future prospects for research include pretreatment, enzymatic hydrolysis and fermentation will also be performed to improve the whole process of ethanol production more economical. And revealing the molecular regulation mechanism of the fast growth of bamboo will provide chance for improving bamboo or other energy plants biomass yield through genetic engineering.


Assuntos
Biocombustíveis , Biotecnologia , Metabolismo dos Carboidratos , Tecnologia de Alimentos , Sasa/metabolismo , Biocombustíveis/análise , Biomassa , Biotecnologia/métodos , Carboidratos/química , Etanol/química , Etanol/metabolismo , Flavonoides/química , Flavonoides/metabolismo , Tecnologia de Alimentos/métodos , Glucuronatos/química , Glucuronatos/metabolismo , Lignina/química , Lignina/metabolismo , Metano/química , Metano/metabolismo , Oligossacarídeos/química , Oligossacarídeos/metabolismo , Sasa/química
17.
Guang Pu Xue Yu Guang Pu Fen Xi ; 34(1): 1-5, 2014 Jan.
Artigo em Chinês | MEDLINE | ID: mdl-24783521

RESUMO

Haze, rain and snow bring a lot of inconvenience in our daily life, especially produce serious potential safety hazard for night transport. In the present paper the authors propose the vision-based dual light sources visibility method to estimate night visibility. This method is significantly advantaged with wide range, high precision and low cost, and has a good robustness in many kinds of weather conditions. Firstly, the authors give the basic visibility estimation model under the atmosphere multiple scattering theory. Secondly, the authors propose the dual light sources method to remove the luminance fluctuations of light sources and the atmosphere light effect, and formulize the algorithm to accurately gain information of light sources from the dual light sources image. At last, the authors design the dual light sources system and conduct a long time experiments under various atmosphere conditions. The experiments show that, with the baseline of 35 m, the visibility range is up to 15 000 m, and relative error is below 20%. This method and system can satisfy the demand of meteorological department and transport agency.

18.
Opt Express ; 19(4): 3599-603, 2011 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-21369183

RESUMO

An optically-controlled terahertz (THz) modulator based on nonlinear photonic crystals (PCs) is proposed, which has the merits of high speed, compactness and easy integration. The PC structure consists of point and line defects. High speed modulation of THz wave can be realized by filling one of the point defects with organic polymer polyaniline which has rapid nonlinear response time. Simulation results show that the modulation rate, modulation depth and insertion loss of the modulator achieve 2.5 GHz, 20.3 dB and 1.02 dB, respectively.

19.
J Environ Sci (China) ; 18(3): 475-81, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-17294643

RESUMO

The pollution of particulate matter less than 2.5 microm (PM2.5) is a serious environmental problem in Beijing. The annual average concentration of PM2.5 in 2001 from seasonal monitor results was more than 6 times that of the U.S. national ambient air quality standards proposed by U.S. EPA. The major contributors to mass of PM2.5 were organics, crustal elements and sulfate. The chemical composition of PM2.5 varied largely with season, but was similar at different monitor stations in the same season. The fine particles (PM2.5) cause atmospheric visibility deterioration through light extinction. The mass concentrations of PM2.5 were anti-correlated to the visibility, the best fits between atmospheric visibility and the mass concentrations of PM2.5 were somehow different: power in spring, exponential in summer, logarithmic in autumn, power or exponential in winter. As in each season the meteorological parameters such as air temperature and relative humidity change from day to day, probably the reason of above correlations between PM2.5 and visibility obtained at different seasons come from the differences in chemical compositions of PM2.5.


Assuntos
Poluição do Ar/análise , Cidades , Monitoramento Ambiental/estatística & dados numéricos , Estações do Ano , China , Umidade , Tamanho da Partícula , Temperatura
20.
J Environ Sci (China) ; 16(5): 860-4, 2004.
Artigo em Inglês | MEDLINE | ID: mdl-15559829

RESUMO

The recent year's monitor results of Beijing indicated that the pollution level of fine particles PM2.5 showed an increasing trend. To understand pollution characteristics of PM2.5 and its relationship with the meteorological conditions in Beijing, a one-year monitoring of PM2.5 mass concentration and correspondent meteorological parameters was performed in Beijing in 2001. The PM2.5 levels in Beijing were very high, the annual average PM2.5 concentration in 2001 was 7 times of the National Ambient Air Quality Standards proposed by US EPA. The major chemical compositions were organics, sulfate, crustals and nitrate. It was found that the mass concentrations of PM2.5 were influenced by meteorological conditions. The correlation between the mass concentrations of PM2.5 and the relative humidity was found. And the correlation became closer at higher relative humidity. And the mass concentrations of PM2.5 were negtive-correlated to wind speeds, but the correlation between the mass concentration of PM2.5 and wind speed was not good at stronger wind.


Assuntos
Poluentes Atmosféricos/análise , Monitoramento Ambiental/estatística & dados numéricos , Estações do Ano , Tempo (Meteorologia) , China , Umidade , Tamanho da Partícula , Espectrometria por Raios X , Fatores de Tempo , Vento
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