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Silicon carbide (SiC) detectors of an Ni/4H-SiC Schottky diode structure and with sensitive areas of 1-4 cm² were fabricated using high-quality lightly doped epitaxial 4H-SiC material, and were tested in the detection of alpha particles and pulsed X-rays/UV-light. A linear energy response to alpha particles ranging from 5.157 to 5.805 MeV was obtained. The detectors were proved to have a low dark current, a good energy resolution, and a high neutron/gamma discrimination for pulsed radiation, showing the advantages in charged particle detection and neutron detection in high-temperature and high-radiation environments.
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With Sophora japonica at the flowering stage as the object, the effect of nitrogen, phosphorus and potassium fertilizers on the yield composition factors, yield and quality of Flos Sophorae Immaturus (FSI) was studied. The results indicated that in early spring, nitrogen, phosphorus and potassium fertilizer on the amplification rate of S. japonica, FSI yield composition, yield and quality were different significantly, middle to high nitrogen (1.5-2.0 kg/plant) significantly increased the level of panicled clusters, raceme and flower bud number and yield. Phosphorus (1.5-2.0 kg/plant) could significantly increase the total buds of flower number and yield, potassium showed no significant increase in yield and yield components. Comprehensively considering yield and quality of FSI, nitrogen 1.5-2.0 kg/plant, phosphorus 1.5-2.0 kg/plant and potassium 0.6-0.9 kg/plant are appropriate.
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Fertilizantes , Flores/crescimento & desenvolvimento , Nitrogênio , Fósforo , Potássio , Sophora/crescimento & desenvolvimento , China , Plantas Medicinais/crescimento & desenvolvimentoRESUMO
The endophytic fungi from root, main stem, branch and leaf of Scrophularia ningpoensis were isolated and identified from Wulong and Chongqing, and the population diversity analysis and phylogenetic analysis were followed. The result indicated that, as to population diversity index, S. ningpoensis from Wulongï¼ leaf>main stem=branch>root, branch from Chongqing>branch from Wulong. Fifty-eight endophytic fungi were obtained, most of which were the pathogens of the plant. Colletotrichum was the prevailing genus, of which C. gloeosporioides and C. boninense were the prevailing strains. Leaf and seedlings might be the main path of infection. Endophytic fungi and pathogen might convert to each other, influenced by such factors as environment, genotype et al.
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Endófitos/classificação , Fungos/classificação , Filogenia , Scrophularia/microbiologia , China , Colletotrichum , Folhas de Planta/microbiologia , Raízes de Plantas/microbiologia , Caules de Planta/microbiologiaRESUMO
The intercellular movement of plant viruses requires both viral and host proteins. Previous studies have demonstrated that the frame-shift protein P3N-PIPO (for the protein encoded by the open reading frame [ORF] containing 5'-terminus of P3 and a +2 frame-shift ORF called Pretty Interesting Potyviridae ORF and embedded in the P3) and CYLINDRICAL INCLUSION (CI) proteins were required for potyvirus cell-to-cell movement. Here, we provide genetic evidence showing that a Tobacco vein banding mosaic virus (TVBMV; genus Potyvirus) mutant carrying a truncated PIPO domain of 58 amino acid residues could move between cells and induce systemic infection in Nicotiana benthamiana plants; mutants carrying a PIPO domain of seven, 20, or 43 amino acid residues failed to move between cells and cause systemic infection in this host plant. Interestingly, the movement-defective mutants produced progeny that eliminated the previously introduced stop codons and thus restored their systemic movement ability. We also present evidence showing that a developmentally regulated plasma membrane protein of N. benthamiana (referred to as NbDREPP) interacted with both P3N-PIPO and CI of the movement-competent TVBMV. The knockdown of NbDREPP gene expression in N. benthamiana impeded the cell-to-cell movement of TVBMV. NbDREPP was shown to colocalize with TVBMV P3N-PIPO and CI at plasmodesmata (PD) and traffic to PD via the early secretory pathway and the actomyosin motility system. We also show that myosin XI-2 is specially required for transporting NbDREPP to PD. In conclusion, NbDREPP is a key host protein within the early secretory pathway and the actomyosin motility system that interacts with two movement proteins and influences virus movement.
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Actomiosina/metabolismo , Nicotiana/metabolismo , Proteínas de Plantas/metabolismo , Plasmodesmos/metabolismo , Via Secretória , Citoesqueleto de Actina/efeitos dos fármacos , Citoesqueleto de Actina/metabolismo , Sequência de Aminoácidos , Brefeldina A/farmacologia , Compostos Bicíclicos Heterocíclicos com Pontes/farmacologia , Inativação Gênica/efeitos dos fármacos , Proteínas de Fluorescência Verde/metabolismo , Modelos Biológicos , Dados de Sequência Molecular , Movimento/efeitos dos fármacos , Mutação , Miosinas/metabolismo , Doenças das Plantas/virologia , Plasmodesmos/efeitos dos fármacos , Potyvirus/patogenicidade , Ligação Proteica/efeitos dos fármacos , Estrutura Terciária de Proteína , Transporte Proteico/efeitos dos fármacos , Proteínas Recombinantes de Fusão/metabolismo , Saccharomyces cerevisiae/metabolismo , Via Secretória/efeitos dos fármacos , Frações Subcelulares/efeitos dos fármacos , Frações Subcelulares/metabolismo , Tiazolidinas/farmacologia , Nicotiana/efeitos dos fármacos , Proteínas Virais/química , Proteínas Virais/metabolismoRESUMO
Microwave-assisted extraction was applied to extract rutin; quercetin; genistein; kaempferol; and isorhamnetin from Flos Sophorae Immaturus. Six independent variables; namely; solvent type; particle size; extraction frequency; liquid-to-solid ratio; microwave power; and extraction time were examined. Response surface methodology using a central composite design was employed to optimize experimental conditions (liquid-to-solid ratio; microwave power; and extraction time) based on the results of single factor tests to extract the five major components in Flos Sophorae Immaturus. Experimental data were fitted to a second-order polynomial equation using multiple regression analysis. Data were also analyzed using appropriate statistical methods. Optimal extraction conditions were as follows: extraction solvent; 100% methanol; particle size; 100 mesh; extraction frequency; 1; liquid-to-solid ratio; 50:1; microwave power; 287 W; and extraction time; 80 s. A rapid and sensitive ultra-high performance liquid chromatography method coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry (EIS-Q-TOF MS/MS) was developed and validated for the simultaneous determination of rutin; quercetin; genistein; kaempferol; and isorhamnetin in Flos Sophorae Immaturus. Chromatographic separation was accomplished on a Kinetex C18 column (100 mm × 2.1 mm; 2.6 µm) at 40 °C within 5 min. The mobile phase consisted of 0.1% aqueous formic acid and acetonitrile (71:29; v/v). Isocratic elution was carried out at a flow rate of 0.35 mL/min. The constituents of Flos Sophorae Immaturus were simultaneously identified by EIS-Q-TOF MS/MS in multiple reaction monitoring mode. During quantitative analysis; all of the calibration curves showed good linear relationships (R² > 0.999) within the tested ranges; and mean recoveries ranged from 96.0216% to 101.0601%. The precision determined through intra- and inter-day studies showed an RSD% of <2.833%. These results demonstrate that the developed method is accurate and effective and could be readily utilized for the comprehensive quality control of Flos Sophorae Immaturus.
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Sophora/química , Cromatografia Líquida de Alta Pressão , Genisteína/isolamento & purificação , Quempferóis/isolamento & purificação , Medicina Tradicional Chinesa , Micro-Ondas , Plantas Medicinais/química , Quercetina/análogos & derivados , Quercetina/isolamento & purificação , Rutina/isolamento & purificação , Espectrometria de Massas por Ionização por Electrospray , Espectrometria de Massas em TandemRESUMO
High-pressure ultrasound-assisted extraction technology was applied to extract ferulic acid, senkyunolide I, senkyunolide H, senkyunolide A, ligustilide and levistolide A from Ligusticum chuanxiong rhizomes. Seven independent variables, including solvent type, pressure, particle size, liquid-to-solid ratio, extraction temperature, ultrasound power, and extraction time were examined. Response Surface Methodology (RSM) using a Central Composite Design (CCD) was employed to optimize the experimental conditions (extraction temperature, ultrasonic power, and extraction time) on the basis of the results of single factor tests for the extraction of these six major components in L. chuanxiong rhizomes. The experimental data were fitted to a second-order polynomial equation using multiple regression analysis and were also examined using appropriate statistical methods. The best extraction conditions were as follows: extraction solvent: 40% ethanol; pressure: 10 MPa; particle size: 80 mesh; liquid-to-solid ratio: 100:1; extraction temperature: 70 °C; ultrasonic power, 180 W; and extraction time, 74 min.
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Medicamentos de Ervas Chinesas/química , Extratos Vegetais/química , Rizoma/química , Benzofuranos/química , Benzofuranos/isolamento & purificação , Cromatografia Líquida de Alta Pressão , Medicamentos de Ervas Chinesas/isolamento & purificação , Humanos , Ligusticum , Análise de Regressão , UltrassomRESUMO
OBJECTIVE: To decide on the optimum artificial domestication cultivation light environment for Paris polyphylla var. chinensis through investigating the effect of light intensity on leaf's gas exchange parameters, photosynthetic parameters, light saturation point and compensation point of Paris polyphylla var. chinensis. METHODS: Different low-light stress gradients' effect on the growth of Paris polyphylla var. chinensis was compared with no low-light stress treatment through calculating leaf's gas exchange parameters, photosynthetic parameters, light saturation point and compensation point, and then all these parameters were statistically analyzed. RESULTS: Light intensity had significant influence on the photosynthetic characteristics of Paris polyphylla var. chinensis. With the strengthening of the low-light stress, chlorophyll content, gas exchange parameters, photosynthetic parameters P., AQY and light saturation point all gradually increased at first, and then decreased. However, both photosynthetic parameters Rd and light compensation point firstly decreased and then rose again. These results showed that too strong or too weak light intensity affected the optimization of photosynthetic parameters of Paris polyphylla var. chinensis. The optimal illuminance for each parameter was not completely same, but they could all reach a relative ideal state when the shading ranges between 40% and 60%. However, photosynthetic parameters deteriorated rapidly when the shading surpass 80%. CONCLUSION: For artificially cultivating Paris polyphylla var. chinensis in Baoxing,Sichuan or the similar ecological region, shading 40%-60% is the optimal light environment, which can enhance the photosynthesis of Paris polyphylla var. chinensis and promote the accumulation of photosynthetic products.
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Liliaceae , Fotossíntese , Estresse Fisiológico , Clorofila , Luz , Folhas de PlantaRESUMO
A simple and quick method is described for the determination of ferulic acid, senkyunolide I, senkyunolide H, senkyunolide A and ligustilide in rhizomes of Ligusticum chuanxiong. The 5 active ingredients in the sample was extracted using 40% ethanol and analyzed by reversed-phase high performance liquid chromatography (HPLC). Chromatography separation was performed using Agilent 1100 series HPLC system with a Symmetry C18 column and gradient elution with a mixture of three solvents : solvent A, acetonitrile, solvent B, methanol and solvent C, 1% aqueous acetic acid, 0 min to 5 min A: B: C 20: 40: 40, 5 min to 30 min A: B: C 60 to 100 : 0 : 40 to 0. The effluent was monitored using a VWD detector set at 321 nm (0-4.3 min) and 275 nm (4.31-30 min). The flow rate was set at 1 mL x min(-1) and the injection volume was 10 microL. The column temperature was maintained at 35 degrees C. The calibration curve was linear (r > or = 0.99) over the tested ranges. The average recovery was 94.44%-103.1% (n = 6). The method has been successfully applied to the analysis in different harvest periods of L. chuanxiong samples. In this paper, single-factor randomized block design to study the 5 components content of L. chuanxiong on ten collecting stages. For the L. chuanxiong collected from April 15th to May 30rd, the content of 5 ingredients increased primarily, and then decreased. Determine the appropriate harvest time has important significance to the promotion of the quality of L. chuanxiong.
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4-Butirolactona/análogos & derivados , Benzofuranos/análise , Cromatografia Líquida de Alta Pressão/métodos , Ácidos Cumáricos/análise , Ligusticum/química , 4-Butirolactona/análise , Ácido Acético/química , Acetonitrilas/química , Metanol/química , Solventes/química , Fatores de TempoRESUMO
BACKGROUND: Primary hepatic lymphoma (PHL) is a lymphoproliferative disorder confined to the liver without peripheral lymph node involvement and bone marrow invasion. PHL is extremely rare in clinical practice. The etiology and pathogenesis of PHL are largely unknown. There are no common standard protocols or guidelines for the treatment of PHL. CASE SUMMARY: We report the case of a 66-year-old man who presented with fever and abdominal pain for three weeks. Computed tomography and magnetic resonance imaging scans showed a pyogenic liver abscess. The patient underwent a right posterior hepatectomy. The surgical pathology revealed aggressive B-cell lymphoma, with a primary consideration of diffuse large B-cell lymphoma of non-germinal center origin. CONCLUSION: This article reviews the characteristics, mechanism and treatment of PHL and provides insight into the diagnosis of PHL.
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OBJECTIVE: To investigate the clinical effect and application value of the modified method of prepuce-degloving repair (PDR) in the treatment of urethrocutaneous fistula (UCF) following hypospadias surgery. METHODS: We retrospectively analyzed 87 cases of UCF caused by hypospadias repair from May 2001 to December 2011, of which 61 were treated by simple closure or Y-V plasty of the fistula (group A), and the other 26 by modified PDR (group B). We compared the success rate of surgery and long-term recurrence between the two groups. RESULTS: The total success rates of repair were 78.7 and 96.2% in groups A and B, respectively. Thirteen cases in group A did not respond to surgery, of which 6 failed to be cured by the second operation but later were treated successfully by modified PDR. In comparison, there was only 1 case of failure in group B, which was cured by a second PDR. CONCLUSION: Modified PDR can significantly improve the success rate and reduce the recurrence rate of UCF after hypospadias surgery, which deserves wide clinical application.
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Procedimentos de Cirurgia Plástica/métodos , Fístula Urinária/etiologia , Fístula Urinária/cirurgia , Criança , Pré-Escolar , Prepúcio do Pênis/cirurgia , Humanos , Hipospadia/cirurgia , Masculino , Estudos Retrospectivos , Resultado do Tratamento , Procedimentos Cirúrgicos Urológicos MasculinosRESUMO
RATIONALE: The relationship between cigarette smoking and acute mountain sickness (AMS) is not clear. OBJECTIVE: To assess AMS risk and altitude acclimatisation in relation to smoking. METHODS: 200 healthy non-smokers and 182 cigarette smokers were recruited from Han lowland workers. These were men without prior altitude exposure, matched for age, health status and occupation, who were transported to an altitude of 4525 masl. MEASUREMENTS: AMS, smoking habits, arterial saturation (SpO2), haemoglobin (Hb), lung function and mean pulmonary artery pressure (PAPm) were assessed upon arrival and after 3 and 6 months. MAIN RESULTS: Compared with non-smokers, smokers had a lower incidence of AMS and lower AMS scores than non-smokers upon arrival; higher Hb and PAPm associated with lower SpO2 at 3 and 6 months at altitude; and lower forced expiratory volume in 1 s and maximal voluntary ventilation at 3 and 6 months. CONCLUSIONS: Smoking slightly decreases the risk of AMS but impairs long-term altitude acclimatisation and lung function during a prolonged stay at high altitude.
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Aclimatação/fisiologia , Doença da Altitude/fisiopatologia , Fumar/fisiopatologia , Adulto , Distribuição de Qui-Quadrado , China , Estudos de Coortes , Feminino , Humanos , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Consumo de Oxigênio/fisiologia , Artéria Pulmonar/fisiologia , Testes de Função Respiratória , Fatores de RiscoRESUMO
Reducing the cost of pellet additives as a substitute for reducing bentonite binder is an important research direction of new pellet additives. There are some industrial solid wastes that have the similar physical and chemical properties to bentonite, and SiO2 content of them may be much lower than bentonite, but also contains a lot of Fe2O3, Al2O3, MgO, B2O3 and other components beneficial to the quality of pellets, which have been paid more attention by many pellet workers. In this review, the effect mechanism of Fe2O3, Na2O/K2O, Al2O3, SiO2, CaO, MgO and B2O3 in the industrial solid wastes on the fired strength and reduction expansion of pellets were systematically summarized. At the same time, the influences of five representative large scale modified industrial solid waste additives including iron tailings, bauxite tailings, fly ash, red mud and boron sludge on the properties of green pellets and finished pellets were described in detail. It can be seen that the applications of industrial solid waste in pellet additives can partially or completely replace bentonite binder, especially fly ash, red mud and boron sludge, which can not only improve the quality of pellets, but also decrease the cost, save energy and reduce pollution, with significant economic benefits.
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5-Amino-1,10-phenanthroline (Phen-NH(2)) is grafted to 3-(triethoxysilyl)-propyl isocyanate (TESPIC) to achieve the organic precursor Phen-Si, which is coordinated to rare earth ions (Sm(3+) or Eu(3+)) and formed Si-O networks with tetraethoxysilane (TEOS) (Phen-Si-RE) after hydrolysis and polycondensation processes to obtain the hybrids Phen-Si-Ln. To investigate the influence of the second ligands to the photophysical properties of the hybrid material Phen-Si-RE, the organic ligand nicotinic acid (NA) and the polymers polyvinylpyrrolidone (PVP) (or PMMA) are further introduced into the above system to assemble the ternary hybrid materials Phen-Si-RE-NA and Phen-Si-RE-PVP (or Phen-Si-RE-PMMA), respectively. These hybrids are amorphous and especially the photophysical properties of them indicate that the introduction of the second ligands is favorable for the luminescence lifetime and quantum efficiency.
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In this study, 26 candidate genes were quantified and normalized in the brain cDNA of common carp (Cyprinus carpio) at 23°C and 6°C using double-standard curve method of real-time quantitative PCR. The results showed that five candidates up-regulated in the samples at 6°C (P<0.01) and quantified 2.11, 13.9, 2.52, 7.38, and 1.83 times more than in the samples at 23°C, respectively. Gene function searching indicated that the protein products of these five candidates were elongation of very long chain fatty acids protein, Acyl-CoA desaturase, Transcription initiation factor IIB, Myo-inositol- 1-phosphate synthase, and Blood-brain barrier HT7 antigen individually. Moreover, seven down-regulated candidates were also identified in the same samples at 6°C (P>0.05), and their expression levels were decreased by 21.8%, 25.9%, 16.6%, 23.7%, 15.8%, 16.3%, and 42.5%, respectively, in comparison with the samples at 23°C. These seven down-regulated candidates mainly participated in the inhibition of glycolysis, improvement of cell apoptosis, and intervention of synapse remodeling based on the results of function searching. The five cold-induced genes identified in this study will be used as important elements for fish with cold sensitive through transgenic technology in future.
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Aclimatação/genética , Encéfalo/metabolismo , Carpas/genética , Carpas/fisiologia , Temperatura Baixa , Regulação da Expressão Gênica , Animais , Cruzamento , Calibragem , Clonagem Molecular , DNA Complementar/genética , Reação em Cadeia da Polimerase , RNA/genética , RNA/isolamento & purificaçãoRESUMO
A compact double-layer wideband 1:60 power divider/combiner based on a radial-line waveguide is designed and investigated for high-power microwave (HPM) applications. Compared with other HPM radial-line power dividers, the proposed power divider is smaller and more compact. The power divider is miniaturized by the double-layer method, and the wideband characteristic is realized by a specially designed wavy disk. Moreover, it can divide the microwave energy into 60 output ports equally by symmetrical design. As for simulation, in the range of 1.64-3.6 GHz, the voltage standing-wave ratio is below 2 (the relative bandwidth is 76%) and the return loss reaches -44 dB at 2.1 GHz. Additionally, a prototype is fabricated and the wideband performance from 1.6 to 2.6 GHz is verified by an existing wideband antenna array. Furthermore, filled with SF6 (0.3 MPa), the theoretical power handling capacity is more than 200 MW and the device works steadily in HPM tests under the condition of 140 MW. To sum up, the compact power divider/combiner has important application potentials in HPM fields.
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To investigate the interaction between Pinus tabuliformis and root microorganisms and its effects on the stability of P. tabuliformis forests, we collected rhizosphere and non-rhizosphere soil from natural and planted P. tabuliformis forests in Huanglong County of Shaanxi Province. The non-rhizosphere soil was used to analyze chemical properties, while the rhizosphere soil was used to isolate and purify phosphorus-solubilizing (organic and inorganic phosphorus) bacteria. We mea-sured the phosphate-solubilizing ability and identified those bacteria using DNA genes sequencing. The results showed that soil total carbon concentration (TC), total nitrogen concentration (TN), carbon:nitrogen (C/N), and nitrogen:phosphorus (N/P) were significantly higher in natural forest than those in the plantation. A total of 20 genera and 65 species of phosphate-solubilizing bacteria were identified in those two forests, with Bacillus, Streptomyces and Pseudomonas as the dominant group. The diversity, richness, and evenness of phosphate-solubilizing bacteria in the natural forest were higher than that in the planted forest, but dominance was lower. Streptomyces was positively correlated with soil TC, TN, C/N and N/P ratios, while Bacillus and Pseudomonas were positively correlated with soil nitrate (NO3-), ammonium (NH4+), available phosphorus (AP), and total phosphorus (TP). The solubilizing ability of phosphate-solubilizing bacteria was different between two forest types, indicating that Pseudomonas sp.34-5 shared in two forests had the strongest phosphate-solubilizing ability for calcium phosphate with 11.40 µg·mL-1 and Bacillus mycoides BF1-5 exclusive to natural forest had the strongest phosphate-solubilizing ability for lecithin with 4.58 µg·mL-1. The composition and structure of phosphorus-solubilizing bacterial community were different in two forest types, with higher diversity, richness and phosphate-solubilizing ability in natural forest than that in plantation.
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Pinus , Rizosfera , Bacillus , Bactérias/genética , China , Florestas , Fosfatos , Solo , Microbiologia do SoloRESUMO
In circular waveguides, the TE01 mode has the lowest transmission loss, which is very suitable for long-distance transmission of high-power microwaves (HPMs). The output mode of HPM sources is mainly the TM01 mode; however, there are few research studies on mode converters of TM01-TE01. In this paper, a high efficiency HPM TM01-TE01 mode converter is designed; compared with the traditional TM01-TE01 mode converters, the structure of the mode converter is compact and easier to process. It is mainly composed of an input circular waveguide, a tapered rectangular waveguide, a 90° bent rectangular waveguide, and an output circular waveguide. A prototype with a center frequency of 2.4 GHz is fabricated and HPM experiments are carried out. The transmission efficiency of this device reaches 99.8% in the simulation, and the measured transmission efficiency is more than 98%. Additionally, the measured power handling capacity is more than 1 GW, which is consistent with simulation. This design has important reference significance for the design of long-distance power transmission devices and HPM mode converters.
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The functional macrocyclic precursors (abbreviated as BC[4]Si and C[4]Si) derive from two kinds of calix[4]arenes, p-tert-butylcalix[4]arene (BC[4]) and calix[4]arene (C[4]) grafted by 3-(triethoxysilyl)propyl isocyanate (TESPIC) through base-initiated nucleophilic addition, and then three series of novel luminescent chemically bonded hybrid material systems (BC[4]Si, RE-BC[4]Si, C[4]Si, and RE-C[4]Si, where RE = Eu, Tb) with organic parts covalently linked to inorganic parts via the functionalized calix[4]arene linkages have been assembled by a sol-gel process, which is characterized by the X-ray diffraction, thermogravimetry/differential scanning calorimetry, scanning electron microscopy, and spectroscopy. It is found that the coordination of rare-earth ions has an influence on the organization and microstructure of the hybrid systems. The photoluminescent behavior (luminescence, lifetime, quantum efficiency, and energy transfer) for these chemically bonded hybrids is studied in detail. Three color luminescences are checked, blue (BC[4]Si and C[4]Si), green (Tb-BC[4]Si and Tb-C[4]Si), and red (Eu-BC[4]Si and Eu-C[4]Si), respectively, suggesting that the intramolecular energy-transfer process between the rare-earth ion and the host takes place within these molecular-based hybrids. Also, especially their quantum efficiencies are determined, which indicates that the different hybrid material systems derived from different functionalized calix[4]arene bridges present different luminescence behavior.
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Isolates of Turnip mosaic virus (TuMV) are divided into four molecular lineages based on host range and geographical origins. Basal-BR is one of the four lineages and represented a new emergent lineage in East Asia. In one previous paper, we report the occurrence of basal-BR isolates in China. Here, we presented the first two complete genomic sequences of Chinese TuMV basal-BR isolates, WFLB06 and TANX2. The genomes of both isolates were 9833 nucleotides excluding the poly(A) tail, and had identical genomic structure. Most of their genes shared the highest identities with Japanese isolates. Recombination analysis showed that WFLB06 was an interlineage recombinant of basal-BR and Asian-BR parents, while TANX2 was an intralineage recombinant of basal-BR parents, and these two isolates represented two novel recombination patterns of TuMV. The ratio of nonsynonymous and synonymous substitution for the P1 gene of Chinese TuMV population was the highest and amounted to 12 times higher than that for the NIa-Pro gene, which implies that the selection pressure on the P1 gene was the highest among the genes present in the genome.
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Brassica napus/virologia , Genoma Viral , Doenças das Plantas/virologia , Potyvirus/genética , Potyvirus/isolamento & purificação , Análise de Sequência de DNA , Substituição de Aminoácidos/genética , China , Análise por Conglomerados , Dados de Sequência Molecular , Recombinação Genética , Homologia de SequênciaRESUMO
The improved magnetically insulated transmission line oscillator (MILO) is a gigawatt-class L-band high power microwave tube driven by a 550 kV, 57 kA, 50 ns electron beam. It has allowed us to generate 2.4 GW pulse of 22 ns duration. The recent progress of the improved MILO is presented in this paper. First, a field shaper cathode is introduced into the improved MILO to avoid the cathode flares in the triple point region. The experimental results show that the cathode flares are avoided, so the lifetime of the velvet cathode is longer than that of the taper cathode. Furthermore, the shot-to-shot reproducibility is better than that of the taper cathode. Second, In order to prolong the pulse duration and increase the radiated microwave power, a self-built 600 kV, 10 Omega, 80 ns pulser: SPARK-03 is employed to drive the improved MILO. Simulation and experimental investigation are performed. In simulation, when the improved MILO is driven by a 600 kV, 57 kA electron beam, high-power microwave is generated with output power of 4.15 GW, frequency of 1.76 GHz, and relevant power conversion efficiency of 12.0%. In experiments, when the diode voltage is 550 kV and current is 54 kA, the measured results are that the radiated microwave power is above 3.1 GW, the pulse duration is above 40 ns, the microwave frequency is about 1.755 GHz, and the power conversion efficiency is about 10.4%.