Reactions between Cr(VI) and wood and its model compounds     

F. S. Jorge  T. M. Santos  J. P. de Jesus  W. B. Banks 《Wood Science and Technology》1999,33(6):487-499

Wood, macromolecular and simple model compounds, were reacted with CrO₃ or K₂CrO₄ aqueous solutions. Extracted lignin, guaiacol, vanillin, vanillyl alcohol and homovanillyl alcohol were chosen as model compounds for lignin, whilst cellulose, gum Ghatti, xylan, extracted hemicellulose from pine, methyl-β-D-glucopyranoside and methyl-β-cellobioside were used as models for wood polysaccharides. The kinetics of the reduction reactions of Cr(VI) were monitored using UV-Vis spectroscopy and the results obtained for several temperatures are discussed. In general terms, wood, lignin and lignin model compounds reduced Cr(VI) faster and to a greater extent than polysaccharides or simple sugar molecules. Moreover, lignin model compounds were reduced even faster than lignin. Simple sugars showed a reduction pattern similar to that of cellulose. Extracted hemicellulose revealed to be a poorer reductant while gum Ghatti was the strongest among the polysaccharides. As expected, CrO₃ aq. behaved as a more powerfull oxidant than K₂CrO₄ aq. for these substances. Even at 100 °C, sugars or polysaccharides did not seem to be oxidised by K₂CrO₄ aq. 0.01 M. These results suggest that, because of the differences in reactivity, lignin reacts preferentially when wood is treated with Cr(VI)-containing formulations, like those which are applied in wood preservation treatments.  相似文献   

Evaluation of procedures to quantify solvent retention in electrospun fibers and facilitate solvent removal     

Anthony R. D’Amato  Nicholas J. Schaub  Jesus M. Cardenas  Erich Franz  Deniz Rende  Alexis M. Ziemba  Ryan J. Gilbert 《Fibers and Polymers》2017,18(3):483-492

Electrospun fiber scaffolds crafted from polyesters are studied extensively for potential tissue engineering applications. For translation of electrospun fibers into the clinic, the FDA requires analysis and quantification of any organic solvent that may be retained in the fibers since many organic solvents can negatively affect cells and tissues. If a significant amount of solvent is retained, then developing procedures for efficient solvent removal may enhance the clinical potential of these materials. In this study we use fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and nuclear magnetic resonance spectroscopy (NMR) to analyze solvent retention. A correlative analysis shows that both FTIR and TGA accurately predicted retention of two different solvents (HFP and chloroform) in our electrospun PLLA scaffolds, thus validating these procedures. We also assess the efficacy of various fiber treatment methods to facilitate organic solvent removal and conclude that submersion in 70 % ethanol and heat treatment at 100 °C were the most efficient methods of removing solvent from electrospun PLLA fibers.  相似文献   

Total Mercury Bioaccumulation in Tissues of Carnivorous Fish (Micropogonias furnieri and Cynoscion acoupa) and Oysters (Crassostrea brasiliana) from Sepetiba Bay,Brazil     

Carla da Silva Carneiro  Eliane Teixeira Mársico  Roberta de Oliveira Resende Ribeiro  Edgar Francisco Oliveira de Jesus 《Journal Of Aquatic Food Product Technology》2013,22(1):96-102

Total mercury (Hg) levels were determined by cold vapor atomic absorption spectrophotometry (CVAAS) in tissues of two species of carnivorous fishes and in the soft tissue of oysters caught in Sepetiba Bay, Brazil. Hg was distributed unevenly in the organs and tissues of the fish; the mean Hg content was highest in the kidneys (0.048 μg/g wet weight) and lowest in the gills (0.004 μg/g w.w.). Mean Hg levels were higher in the oysters (0.052 μg/g w.w.) than in the fish (0.022 μg/g w.w). The total Hg concentration did not exceed the maximum concentration for food allowed by Brazilian legislation in any of the fish and oyster samples analyzed. Moreover, the Hg concentrations observed were all within the maximum level for fish recommended by the Food and Agriculture Organization (FAO; 0.5 μg/g w.w.).  相似文献   

Impacts of rainstorms on soil erosion and organic matter for different cover crop systems in the western coast agricultural region of Syria     

Safwan Mohammed  Ebaa Hassan  Hazem Ghassan Abdo  Szilard Szabo  Ali Mokhtar  Karam Alsafadi  Issam Al‐Khouri  Jesus Rodrigo‐Comino 《Soil Use and Management》2021,37(1):196-213

More and more cultivated coastal territories of Syria are being affected by increasing land degradation processes, specifically, by soil erosion due to non‐sustainable soil management. The use of cover crops can be considered an ideal solution to reduce the negative impacts of extreme rainfall events on soil erosion. However, there is no enough information about the main cultivated areas of Syria due to the current conflicts and the very few types of research conducted there. Therefore, the main aim of this research was to assess soil erosion (soil loss and sediment concentration) and hydrological response (run‐off and infiltration) considering the impact of different types of cropping systems on soil organic matter. To achieve this goal, using erosion plots, five grouped natural rainfall events and soil samples were collected, and infiltration measurements were performed between November 2012 and April 2013 (rainy season) on three different cropping systems (wheat, vetch, bean and control) with different sloping gradients (8% and 20%) in Tartous governorate (W Syria). Our results showed a cumulative rainfall amount from 68.8 to 201 mm during the study period. The highest sediment yield was generated in the control and wheat plots, registering 0.468 and 0.368 kg m^?2, respectively, with an inclination of 8%. For an inclination of 20%, the control and wheat plots registered 1.145 and 0.967 kg m^?2, respectively. In comparison with the control plots, there was a decrease in the total eroded organic matter, which ranged from 0.0579 (control) to 0.0289 (bean) kg m^?2 year^?1 in the plots with 20% inclination, and from 0.0233 (control) to 0.0069 (bean) kg m^?2 year^?1 with 8% inclination. To sum up, bean and vetch play an effective role to mitigate soil erosion, delay run‐off and reduce sediment yield. The output of this research provides first insights into the impact of different land uses on soil loss. Also, it could help rural inhabitants and farmers to correctly manage their soils against soil erosion processes.  相似文献   

Soil biology and warming play a key role in the release of ‘old C’ from organic soils     

Maria Jesus Iglesias Briones  Mark H. Garnett 《Soil biology & biochemistry》2010,42(6):960-299

A radiocarbon approach was used to investigate the roles of temperature and soil fauna activity in the turnover of ‘old’ non-labile carbon in a peatland ecosystem. We investigated the impacts of enchytraeids on carbon turnover in two different soil layers, with different incorporation of the ‘bomb’ peak, when incubated at two different temperatures. Results showed that, in agreement with previous studies, warmer temperatures promoted reproduction rates of enchytraeids, with the top layer supporting higher animal densities and biomass. With independence of the animal treatment, soil respiration in the top 5 cm was four times higher than in the deeper layer suggesting that decomposition was greater in the upper layer, with the response being greater at the highest temperature treatment. Furthermore, independent of temperature, the presence of enchytraeids in the top layer significantly enhanced the release of non-labile C as DOC. Similarly, at the bottom layer, ‘older’ C sources were mobilised in response to warming and a greater amount of pre-bomb carbon was released into the soil solution at 20 °C when the worms were present. A strong positive link between the ages of the C assimilated by the animals and released through mineralization suggests an important role of soil biology in the mobilisation of the older C pools in soils and should be taken into account in developing global C models to predict the response of soil C dynamics to climate change.  相似文献   

Testing usability of a user interface in an embedded device for ELISA plate analysis     

Jesus Ángel Baro  María Concepción López-Díaz 《Computers and Electronics in Agriculture》2011,76(2):325-330

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Left ventricular inflow tract obstruction secondary to a myxoma in a dog     

Fernandez-del Palacio MJ  Sanchez J  Talavera J  Martínez C 《Journal of the American Animal Hospital Association》2011,47(3):217-223

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In vitro susceptibility of fluconazole-susceptible and -resistant isolates of Malassezia pachydermatis against azoles     

Jesus FP  Lautert C  Zanette RA  Mahl DL  Azevedo MI  Machado ML  Dutra V  Botton SA  Alves SH  Santurio JM 《Veterinary microbiology》2011,152(1-2):161-164

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In‐season calcium‐spray formulations improve calcium balance and fruit quality traits of peach     

Jesus Val  Victoria Fernández 《植物养料与土壤学杂志》2011,174(3):465-472

Experiments to evaluate the effect of in‐season calcium (Ca) sprays on late‐season peach (Prunus persica L. Batsch cv. Calrico) were carried out for a 2‐year period. Calcium formulations (0.5% and 1.0% in 2008 and only 0.5% tested in 2009) supplied either as CaCl₂ or Ca propionate in combination with two or three adjuvants (0.05% of the nonionic surfactants Tween 20 and Break Thru, and 0.5% carboxymethylcellulose, CMC) were sprayed four to five times over the growing season. Peach mesocarp and endocarp Ca concentrations were determined on a 15‐day basis from the beginning of May until the end of June. Further tissue analyses were performed at harvest. A decreasing trend in fruit Ca concentrations over the growing season was always observed regardless of the Ca treatments. Both in 2008 and 2009, significant tissue Ca increments associated with the application of Ca‐containing sprays in combination with adjuvants were only observed in June, which may be coincident with the period of pit hardening. In 2008, both at harvest and after cold storage, the total soluble‐solids concentration (° Brix) of fruits supplied with Ca propionate (0.5% and 1.0% Ca) was always lower as compared to the rest of treatments. The application of multiple Ca‐containing sprays increased firmness at harvest and after cold storage, especially when CaCl₂ was the active ingredient used. Supplying the adjuvants Tween 20 and CMC increased fruit acidity both at harvest and after cold storage. Evaluation of the development of physiological disorders after cold storage (2 weeks at 0°C) indicated a lower susceptibility of Ca‐treated fruits to internal browning. Fruits treated with multiple CaCl₂‐, CMC‐, and Break Thru®‐containing sprays during the growing season were significantly less prone to the development of chilling injuries as compared to untreated peaches.  相似文献   

Effects of continuously infusing glucose or casein into the terminal ileum on biomarkers of metabolism,inflammation, and intestinal morphology in growing pigs     

Edith J Mayorga  Erin A Horst  Mohmmad Al-Qaisi  Brady M Goetz  Megan A Abeyta  Sonia Rodríguez-Jimnez  Samantha Lei  Jesus A Acosta  John F Patience  Mariana C Rossoni Serao  Lance H Baumgard 《Journal of animal science》2021,99(7)

Study objectives were to determine the effects of continuously infusing glucose (GLC) or casein (CAS) into the terminal ileum on biomarkers of metabolism, inflammation, and intestinal morphology in growing pigs. Crossbred gilts (n = 19; 81 ± 3 kg body weight [BW]) previously fitted with T-cannulas at terminal ileum were used in the current experiment. Following 4 d of acclimation, pigs were enrolled in 2 experimental 4-d periods (P). During P1, pigs were housed in individual pens and fed ad libitum for collection of baseline parameters. At the beginning of P2, pigs were assigned to 1 of 3 infusion treatments: 1) control (CON; water; 3 liters/d; n = 7), 2) GLC (dextrose 50%; 500 g/d; n = 6;), or 3) CAS (casein sodium salt; 300 g/d; n = 6). Water, GLC, and CAS solutions were continuously infused at a rate of 125 mL/h for the entirety of P2. Animals were euthanized at the end of P2, and intestinal tissue was collected. During P2, average daily feed intake differed across treatments and was reduced in GLC compared with CON pigs (14%), while CAS pigs consumed an intermediate amount (P = 0.05). Average daily gain and final BW were similar across treatments. A treatment by time interaction was observed for blood urea nitrogen (BUN; P < 0.01), as it decreased in GLC (21%) while it gradually increased in CAS (76%) pigs relative to CON pigs. Mild hyperthermia occurred with both GLC and CAS infusions relative to CON (+0.3 and 0.2 °C, respectively; P < 0.01). Blood neutrophils increased in CAS relative to CON pigs (26%) but remained similar between CON and GLC treatments (P < 0.01). Blood monocytes decreased in GLC relative to CON pigs (24%) while CAS pigs had an intermediate value (P = 0.03). Circulating lipopolysaccharide binding protein tended to decrease in GLC (29%) relative to CON pigs but remained similar between CON and CAS pigs (P = 0.10). Plasma tumor necrosis factor-alpha was similar across treatments. Ileum villus height:crypt depth was increased in CAS compared with CON pigs (33%; P = 0.05) while GLC pigs had an intermediate value. Colon myeloperoxidase-stained area increased in CAS compared with CON pigs (45%; P = 0.03) but remained similar between GLC and CON pigs. In summary, continuously infusing GLC or CAS into the terminal ileum appeared to stimulate a mild immune response and differently altered BUN patterns but had little or no effects on blood inflammatory markers, intestinal morphology, or key production parameters.  相似文献