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21.
Soils of a toposequence formed chiefly in Tertiary marls in the south-eastern part of the “Bassin Aquitain” have been studied by field and micromorphological methods. Profiles were examined in detail in the field and oriented samples taken of horizons for observations of micromorphology. From the upper to the lower part of the toposequence, the four profiles also form a chronosequence, viz., a recent calcareous brown soil (sol brun calcaire), an old calcic brown soil (sol brun calcique), a still older leached brown soil (sol brun lessivé) and a hydromorphic leached soil (sol lessivé hydromorphe).The profile distribution and forms of calcite can be related to the morphology, ages and parent materials of the soils. Calcite is found as relics in the upper horizons of the calcareous brown soil and in the form of accumulations in the Bca and Cca horizons of the calcareous brown soil, the calcic brown soil and the leached brown soil. Where accumulations are limited, calcite forms pseudomycelia associated with roots, first as calcitans in tabular pores or craze planes and second as coalescing pseudomycelia. Finally, the calcite invades the S-matrix by epigenesis and results in crumbly masses. These masses have the shapes of the structural voids originally present in the parent materials. The common voids in the marl are vertical craze planes, the widths of which differ with the moisture regime of a soil. In the sandstones, the craze planes are horizontal and very small. The distribution of the calcitans and the presence of the crumbly masses indicate that the processes of accumulation of calcite are in part biodependent, i.e., related to root distribution, and in part lithodependent, i.e., related to structure of the parent rock.Finally, the presence in the calcareous brown soil of calcite as relics in the upper horizons and as successions of cutans from outsides to insides of pores (calcitan, argillan, calcitan) in the Bca horizon shows that the profile has a polycyclic origin. 相似文献
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Atomic force microscopy and dissection of gap junctions 总被引:16,自引:0,他引:16
An atomic force microscope (AFM) was used to study the structure of isolated hepatic gap junctions in phosphate-buffered saline (PBS). The thickness of these gap junctions appears to be 14.4 nanometers, close to the dimensions reported by electron microscopy (EM). When an increasing force is applied to the microscope tip, the top membrane of the gap junction can be "dissected" away, leaving the extracellular domains of the bottom membrane exposed. When such "force dissection" is performed on samples both trypsinized and fixed with glutaraldehyde, the hexagonal array of gap junction hemichannels is revealed, with a center-to-center spacing of 9.1 nanometers. 相似文献
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Pirjo Mattila Sari Mäkinen Merja Eurola Taina Jalava Juha-Matti Pihlava Jarkko Hellström Anne Pihlanto 《Plant foods for human nutrition (Dordrecht, Netherlands)》2018,73(2):108-115
The goal of this work was to analyze nutritional value of various minimally processed commercial products of plant protein sources such as faba bean (Vicia faba), lupin (Lupinus angustifolius), rapeseed press cake (Brassica rapa/napus subsp. Oleifera), flaxseed (Linum usitatissimum), oil hemp seed (Cannabis sativa), buckwheat (Fagopyrum esculentum), and quinoa (Chenopodium quinoa). Basic composition and various nutritional components like amino acids, sugars, minerals, and dietary fiber were determined. Nearly all the samples studied could be considered as good sources of essential amino acids, minerals and dietary fiber. The highest content of crude protein (over 30 g/100 g DW) was found in faba bean, blue lupin and rapeseed press cake. The total amount of essential amino acids (EAA) ranged from 25.8 g/16 g N in oil hemp hulls to 41.5 g/16 g N in pearled quinoa. All the samples studied have a nutritionally favorable composition with significant health benefit potential. Processing (dehulling or pearling) affected greatly to the contents of analyzed nutrients. 相似文献
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Marjamaa K Lehtonen M Lundell T Toikka M Saranpää P Fagerstedt KV 《Tree physiology》2003,23(14):977-986
We examined the relationship between beta-glucosidase and peroxidase activities and xylem lignification in the stems of Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies (L.) Karst.) and silver birch (Betula pendula Roth) during the 1999 growing season. Examination of stem cross sections stained with safranin and Alcian blue for lignin and cellulose, respectively, indicated that radial growth of pine and spruce xylem began in late May, whereas the growth of birch xylem was initiated 2 weeks later. Lignification began soon after thickening of the newly formed cell walls, i.e., upon deposition of cellulose. Hydrolysis of the synthetic beta-glucosidase substrate p-nitrophenyl-beta-O-D-glucopyranoside was correlated with radial growth and lignification in the xylem of both conifers, but the relationship between lignification and the hydrolysis of coniferin by beta-glucosidase was not obvious. Beta-glucosidase activities in the xylem of silver birch were low and did not correlate with growth or lignification with either substrate. An increase in peroxidase activity was detected at the initiation of growth and lignification in the conifers and during growth and lignification in silver birch, but high peroxidase activities were also measured outside the growth period during late autumn, winter and early spring. 相似文献
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Leaching of nitrogen (N) and phosphorus (P) through container peatmedium and N and P uptake by seedlings were determined in commercial productionof birch grown with three different types of fertilization. Half of the amountof nutrients was premixed into the peat medium and the other half was appliedasliquid (=fertigated) in the treatment (PF) commonly used in Finland. In twoother treatments all nutrients, either totally (P-VN) or partly (P-N) inslow-release form, were premixed into the peat. Independently of the treatment,the largest proportion (60 to 80%) of total N leached during May and June.During two growing seasons, the amounts of N leached from PF treatments (9 to36kg ha–1) were as large as the amounts of Nleachedfrom P-VN and P-N treatments (24 to 46 kg ha–1).Due to fertigations between container trays, however, the total N load perhectare was greatest in the PF treatments. In the soil water 0.5meter beneaththe container area, the N concentration varied from 10 to 60 mgl–1. The morphological and chemical properties of theseedlings did not differ greatly between treatments. 相似文献
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The aim of the study was to establish normal echocardiographic values of healthy Standardbred trotters not published previously. Twenty-three clinically normal horses weighing between 350 and 490 kg were examined in the same manner: first a thorough physical and then detailed echocardiographic examination were performed. Standardised two-dimensional (2D) and guided M-mode echocardiographic imaging techniques were used to measure interventricular septal thickness (IVS), left ventricular internal diameter (LVID), left ventricular wall thickness (LVW), left atrial internal diameter (LAID) in end-systole (s) and end-diastole (d) and aortic diameter (AOD) in end-diastole. Mean, range and standard deviation of the different parameters were calculated. The mean values (in centimetres) were as follow (2D/M-mode): IVSs: 4.6/4.7; IVSd: 3.1/3.0; LVIDs: 7.0/7.0; LVIDd: 10.7/10.7; LVWs: 3.9/3.9; LVWd: 2.7/2.7; LAIDs: 10.4/-; LAIDd: 11.3/-; AODd: 7.2/-. Results of two-dimensional and M-mode measurements were compared to each other and to normal values obtained from other breeds. 相似文献
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Darees Boucher V. Revel J. C. Guiresse M. Kaemmerer M. Bailly J. R. 《Water, air, and soil pollution》1999,112(3-4):229-239
The release of ammonia nitrogen during composting of sewage sludge mixed with a lignocellulosic bulking agent leads to a reduction in the agronomic value of the final compost and to harmful effects on the environment. We propose adding a cheap salt FeCl3 which can be used without special precaution to reduce ammonia losses by decreasing pH conditions. An in-vessel co-composting experiment was conducted in a large reactor (100 L) in which FeCl3 was added to sludge mixed with a bulking agent (pine shavings and sawdust) and compared with a control mixture without FeCl3. Temperature, oxygen consumption and pH were monitored throughout the composting of both mixtures. The final balance of organic matter, organic and inorganic nitrogen permitted to conclude that the addition of FeCl3 reduced nitrogen loss (by a factor of 2.4 in relation to the control) and increased mineralisation of the organic nitrogen by 1.6. 相似文献