龙竹的机械、热和微观结构分析     

Almeida A. L. F. S. D.  Mauricio M. H. P.  Almeida J. R. M. D. 《世界竹藤通讯》2010,8(6):45

在龙竹竹杆的3个不同高度取材加工成竹条,并浸泡在蒸馏水中,记录竹条的老化时间,分析龙竹条的抗弯机械性能。对于未加工的竹条,抗弯性能并不随着秆高而变化。相对于未老化的标本,老化的标本的断裂模数降低,并且从秆底部到秆上部减少。同时,通过对未老化标本和老化标本的比较,老化标本的抗弯模数也呈下降趋势,但对于取自同一部位且浸泡时间相同的标本而言,抗弯模数没有变化。利用光学显微技术和数字图象处理技术对杆不同部位的微观结构的变化进行评估。利用镶嵌技术分析横切面,这能够测量大量纤维的数量。结果表明,从数据来讲,在杆的各个高度,主要结构参数(如单位面积的纤维数量)无变化。然而,不同部位的纤维形态有所不同,在杆上部可发现更长的纤维。可用热解重量分析法确定龙竹的热性能。热降解过程中在单阶段发生,并于280.10C开始。在此过程中,可获得166KJ/mol的活化能。  相似文献   

Edible mushrooms: Role in the prevention of cardiovascular diseases     

Eva Guillamón  Ana García-Lafuente  Miguel Lozano  Matilde D´Arrigo  Mauricio A. Rostagno  Ana Villares  José Alfredo Martínez 《Fitoterapia》2010

Edible mushrooms are a valuable source of nutrients and bioactive compounds in addition to a growing appeal for humans by their flavors and culinary features. Recently, they have become increasingly attractive as functional foods for their potential beneficial effects on human health. Hence, food industry is especially interested in cultivated and wild edible mushrooms.  相似文献   

A comparison of pod production and insect ratings of 12 elite Prosopis alba clones in a 5-year semi-arid Argentine field trial     

Mauricio Ewens  Peter Felker 《Forest Ecology and Management》2010

Semi-arid adapted nitrogen fixing trees of the genus Prosopis have been extensively used in Argentina for soil improvement, luxury quality lumber production and sweet (35% sucrose) pods for humans and livestock. Due to the great demand of Prosopis alba for lumber, erect, tall, high pod producing trees of this species have been greatly overharvested, leading to erosion of the gene pool. A previous progeny trial with 57 half sib families identified 12 trees with promise for rapid growth, high production of pods and sweet pods. This trial, on a site with a salinity of 8.6 dS m⁻¹ EC and a pH of 7.7, examined clones of these 12 trees in a randomized complete block trial with 8 single tree replications for height, basal diameter, canopy height and diameter, production of pods, sensory characteristics of the pods, disease resistance and insect resistance. In the 5th year of production and 7th year from planting, three clones produced more than 50 kg pods per tree versus 32 kg for check. At this 10 m × 10 m spacing, this yield of 5000 kg/ha compares favorably to many other semi-arid crops, especially given the unfavorable salinity and pH. In contrast to genetic improvement in pod production, the clones had lower diameter, height and canopy growth than the check. The lower biomass production may be due to fibrous root system produced from cuttings, since some of the clones blew over in high winds but none of the checks produced from seed blew over. Companion seed orchards of salt tolerant clones may provide rootstock for these high pod production clones. Significant differences in insect and disease resistance of the clones were observed and full sib crosses were made to study the genetics of the resistance. All clones had good sensory properties for use in human food. This is the first replicated trial with multipurpose clones useful for lumber and human food. The annual diameter growth rates ranged from 2.8 to 4.1 cm year⁻¹ which was estimated to produce an internal return of approximately 20% from lumber alone.  相似文献   

Quantum yield of non-regulated energy dissipation in PSII (Y(NO)) for early detection of leaf rust (Puccinia triticina) infection in susceptible and resistant wheat (Triticum aestivum L.) cultivars     

K. Bürling  M. Hunsche  G. Noga 《Precision Agriculture》2010,11(6):703-716

The development and optimization of protocols for the precise and pre-symptomatic detection of diseases, and non-invasive evaluation of genotype-specific pathogen resistance enabling selection of the more promising genotypes in breeding programmes are important and often overlooked topics in precision agriculture. The increasing pressure to minimize both production costs and the environmental impact of pesticides forces the search for rapid and objective methods of screening pathogen resistance. Using the non-destructive pulse amplitude modulated (PAM) chlorophyll fluorescence imaging technique, we hypothesized that not only disease detection but also discrimination between differences in the level of resistance of wheat cultivars to the leaf rust (Puccinia triticina Erics.) pathogen can be achieved. Experiments were conducted using the cultivars Dekan and Retro as representatives of a susceptible and a highly resistant genotype, respectively. Fluorescence measurements were carried out daily on the control and on plants inoculated with P. triticina until the first small red-brown pustules appeared in the centre of chlorotic spots. In response to pathogen inoculation, the fluorescence readings showed an early characteristic increase in Y(NO) in both resistant and susceptible cultivars. The susceptible cultivar, however, showed a more pronounced difference between Y(NO) values measured on the control and inoculated leaves as well as a distinct evolution over time. Accordingly, our results indicate that Y(NO) might be suitable for discriminating between wheat genotypes as early as 2 days after inoculation. Thus, the proposed protocol might be adopted as an additional tool for the early screening of new genotypes, especially in breeding programs that aim for high resistance to disease and low crop variability for precision agriculture. However, its implementation in experimental field plots requires improvement of the measurement system and establishment of appropriate algorithms for disease pattern recognition and data analysis.  相似文献   

Proteolytic digestive enzymes and peritrophic membranes during the development of Plodia interpunctella (Lepidoptera: Piralidae): targets for the action of soybean trypsin inhibitor (SBTI) and chitin-binding vicilin (EvV)     

Amorim TM  Macedo LL  Uchoa AF  Oliveira AS  Pitanga JC  Macedo FP  Santos EA  de Sales MP 《Journal of agricultural and food chemistry》2008,56(17):7738-7745

The digestive system of P. interpunctella was characterized during its larval development to determine possible targets for the action of proteinaceous enzyme inhibitors and chitin-binding proteins. High proteolytic activities using azocasein at pH 9.5 as substrate were found. These specific enzymatic activities (AU/mg protein) showed an increase in the homogenate of third instar larvae, and when analyzed by individual larvae (AU/gut), the increase was in sixth instar larvae. Zymograms showed two bands corresponding to those enzymatic activities, which were inhibited by TLCK and SBTI, indicating that the larvae mainly used serine proteinases at pH 9.5 in their digestive process. The presence of a peritrophic membrane in the larvae was confirmed by chemical testing and light microscopy. In a bioassay, P. interpunctella was not susceptible to the soybean trypsin inhibitor, which did not affect larval mass and mortality, likely due to the weak association with its target digestive enzyme. EvV (Erythrina velutina vicilin), when added to the diet, affected mortality (LD50 0.23%) and larval mass (ED50 0.27%). This effect was associated with EvV-binding to the peritrophic membrane, as seen by immunolocalization. EvV was susceptible to gut enzymes and after the digestion process, released an immunoreactive fragment that was bound to the peritrophic matrix, which probably was responsible for the action of EvV.  相似文献   

Index of geoaccumulation and spatial distribution of potentially toxic elements in the Serra Pelada gold mine     

Teixeira  Renato Alves  de Souza  Edna Santos  de Lima  Mauricio Wilians  Dias  Yan Nunes  da Silveira Pereira  Wendel Valter  Fernandes  Antonio Rodrigues 《Journal of Soils and Sediments》2019,19(7):2934-2945

Journal of Soils and Sediments - The concentration and spatial distribution of many potentially toxic elements (PTEs) have not been studied in the mining areas of tropical soils in the Amazon. The...  相似文献   

Fish farming of native species in Colombia: current situation and perspectives     

Pablo Emilio Cruz‐Casallas  Víctor Mauricio Medina‐Robles  Yohana María Velasco‐Santamaría 《Aquaculture Research》2011,42(6):823-831

In Colombia and the rest of the world, the decrease in capture fisheries production has turned the aquaculture into an alternative source of protein for the populations food security as well as an important productive activity, generating employment and income for the rural communities. The Colombian pisciculture is based on red Tilapia Oreochromis sp. (Linnaeus), Rainbow trout Oncorhynchus mykiss (Walbaum) and cachama blanca Piaractus brachypomus (Cuvier), which currently represent around 96% of the total national production. The remaining 4% comes from other farmed species such as bocachico Prochilodus magdalenae (Steindachner), carp Cyprinus carpio (Linnaeus) and yamúBrycon amazonicus (Spix & Agassiz). From the three main fish species, cachama blanca is the only native species, which has shown excellent performance in pond farming due to its rusticity, omnivorous habits, docility, meat quality, food conversion and disease resistance. The limited offer of Colombian fish farmed species determines its currently low competitiveness and restricted impact on the international markets; thus making necessary to explore the potential of new fish species in order to introduce them to the pisciculture system and to expand the range of fish farming species. A good alternative is the introduction of native catfish, which have great potential for fish farming activity.  相似文献   

Evaluation of an epidemic of sporotrichosis in cats: 347 cases (1998-2001)     

Schubach TM  Schubach A  Okamoto T  Barros MB  Figueiredo FB  Cuzzi T  Fialho-Monteiro PC  Reis RS  Perez MA  Wanke B 《Journal of the American Veterinary Medical Association》2004,224(10):1623-1629

OBJECTIVE: To evaluate characteristics of a large epidemic of sporotrichosis in cats. DESIGN: Retrospective study. ANIMALS: 347 cats with naturally acquired infection with Sporothrix schenckii. PROCEDURE: Medical records were reviewed for data regarding clinical, mycologic, histopathologic, and routine hematologic and serum biochemical findings; assays for FIV-specific antibodies and FeLV antigen; antifungal treatment; and follow-up. RESULTS: Lesions varied from small papules to extensive zones of necrosis.Ten cats had no skin lesions, 114 had skin lesions at a single site, 86 had skin lesions in 2 sites, and 137 had skin lesions in 3 or more sites. Respiratory tract signs were observed in 154 cats and were the most frequent extracutaneous sign. Anemia, leukocytosis with neutrophilia, hypoalbuminemia, and hyperglobulinemia were the main blood abnormalities. Antibodies against FIV were detected in 28 cats, FeLV antigen was detected in 2 cats, and both were detected in 1 cat among 142 cats tested. During the study, 118 cats were lost to follow-up and 124 died. Of 266 cats that were treated, 68 were cured. Complete healing of the lesions was observed regardless of the presence of extracutaneous signs, general condition, treatment schedule, or coinfection with FIV. CONCLUSIONS AND CLINICAL RELEVANCE: Feline sporotrichosis was evident in subclinical to severe forms; however, cats can respond well to regular and prolonged antifungal treatment.  相似文献   

Can ultraviolet light C decrease the environmental burden of antimicrobial‐resistant and ‐sensitive bacteria on textiles?          下载免费PDF全文

Jennifer J. Bentley  Domenico Santoro  Dunbar W. Gram  Mauricio Dujowich  Rosanna Marsella 《Veterinary dermatology》2016,27(6):457-e121

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Solventless Microextraction Techniques for Determination of Trihalomethanes by Gas Chromatography in Drinking Water     

Milton Moreano Rosero  Mauricio Aguirre  Davinson Pezo  Gonzalo Taborda  Carmen Dussán  Cristina Nerin 《Water, air, and soil pollution》2012,223(2):667-678

Three different solventless sample preparation techniques based on microextraction, membrane extraction, and headspace extraction have been developed and optimized for determination of trihalomethanes in drinking water by gas chromatography electron capture detector and mass spectrometry detection. The techniques employed were headspace (HS) solid-phase microextraction, hollow fiber liquid-phase microextraction (HFLPME) and HS extraction. All techniques used were optimized with different experimental designs in order to select the most relevant variables which significantly affect the different processes. The different analytical figures of merit such as limit of detection (LOD), limit of quantification, reproducibility, accuracy, and linear dynamic range were obtained. The new HFLPME method applied used a hollow fiber membrane of polypropylene and the optimized variables were extraction time, extraction temperature, and salting-out effect. The software MODDE 6.0 was used and its design was one central composite on face with a total of 17 runs. The best conditions for the HFLPME were 20 min, 40°C, and 10% NaCl, respectively. The LODs ranged from 0.018 μg·L⁻¹ (for CHClBr₂) to 0.049 μg·L⁻¹ (for CHBr₃), being this technique the most sensitive one among those studied. Finally, after having optimized the sample preparation techniques and chromatographic conditions, several water samples were taken in two different water treatment plants in Spain (Zaragoza) and Colombia (Viterbo, Caldas). The results obtained are shown and discussed.  相似文献