Heat treatments change the chemical and physical properties of wood and dimensional stability and hygroscopicity are affected
as a result of modifications of wood cell components. This study evaluated the water absorption of wood specimens treated
with boron compounds followed by heat treatment. Sugi (Cryptomeria japonica D. Don) sapwood specimens treated with either boric acid (BA) or disodium octoborate tetrahydrate (DOT) solutions were heat-modified
at either 180° or 220°C for 2 or 4 h. Carbohydrate composition and water absorption of the specimens were then measured and
compared with those of untreated and unheated specimens. Wood carbohydrates were significantly degraded in the specimens after
heat treatment. The heat treatment evidently decreased the water absorption and the heat-modified specimens absorbed less
water than unheated specimens. The higher the treatment temperature and the longer the treatment time, the lower the amount
of absorbed water. The boron-treated and heat-modified specimens, however, showed increased water absorption due to the hygroscopic
properties of BA and DOT. 相似文献
The effect of pruning all branches (complete pruning) or retaining one branch (partial pruning) on the dynamics of nitrogen
cycling in aboveground biomass, nitrogen supplying power of an amended Eutric Cambisol, and fine root length, was studied
in an Erythrina poeppigiana (Walp.) O.F. Cook—tomato (Lycopersicon esculentum Mill.) alley cropping practice in Turrialba, Costa Rica during 1999–2000. Over the 1 year pruning cycle, in which trees were
completely or partially pruned four times, respective aboveground biomass production was 4.4 Mg or 7 Mg ha−1 (2-year-old trees) and 5.5 Mg or 9 Mg ha−1 (8-year-old trees); N cycled in aboveground biomass was 123 kg or 187 kg ha−1 (2-year-old trees) and 160 kg or 256 kg N ha−1 (8-year-old trees); mean fine root length was 489 or 821 m (2-year-old-trees), 184 or 364 m per tree (8-year-old-trees).
Pruning intensity did not significantly affect net N mineralisation and net nitrification rates during the tomato-cropping
season. For the tomato crop, pre-plant mean net N mineralisation rate of 2.5 mg N kg−1 soil day−1 was significantly lower than 16.7 or 11.6 mg N kg−1 soil day−1 at the end of vegetative development and flowering, respectively. Mean net nitrification rates of 3.5, and 4.3 mg N kg−1 soil day−1, at pre-plant and end of vegetative development, respectively, were significantly higher than 0.3 mg N kg−1 soil day−1 at end of flowering. In humid tropical low-input agroforestry practices that depend on organic inputs from trees for crop
nutrition, retention of a branch on the pruned tree stump appears to be a good alternative to removal of all branches for
reducing N losses through higher N cycling in aboveground biomass, and for conserving fine root length for higher N uptake,
although it might enhance competition for associated crops. 相似文献
Landscape Ecology - Agricultural expansion is a principal driver of biodiversity loss, but the impacts on community assembly in agro-ecosystems are less clear, especially across regional scales at... 相似文献
With underrepresentation of habitats in publicly protected areas, attention has focused on the function of alternative land conservation mechanisms. Private conservation easements (CEs) have proliferated in the United States, yet assessing landscape-level function is confounded by varying extent, resolution, and temporal scale.
Objectives
We developed and tested an assessment tool to evaluate interacting spatial, social, and environmental attributes of easements relative to the degree of human modification (HM). We hypothesized that on both private and public conservation properties HM would be lower than on non-conserved parcels, and that for fine-scale features (most CEs), the level of HM would be driven by the variables used to create the coarser scale HM measure.
Methods
Variation in HM between private, public, and non-conserved was tested via pairwise parcel sampling. Composition was evaluated using multiple geographic bounds and edge characteristics. We assessed both environmental and social predictors using multinomial logistic regression.
Results
Privately conserved lands did not differ significantly from non-conserved lands. Publicly conserved lands had lower HM than both privately conserved and non-conserved lands. Edge contrast was similar between private and matched non-conserved patches. The level of HM was not driven by distance to roads, or by elevation in this mixed-use setting.
Conclusions
Variation in tests for differences, land characteristics, and HM variables confirmed the significantly lower HM of publicly protected lands, and opens the question as to naturalness of easements in some contexts. CEs in this location may be representative of the mixed rural-forested landscape instead of more natural land cover.
Lupinus albus seeds contain conglutin gamma (Cγ) protein, which exerts a hypoglycemic effect and positively modifies proteins involved in glucose homeostasis. Cγ could potentially be used to manage patients with impaired glucose metabolism, but there remains a need to evaluate its effects on hepatic glucose production. The present study aimed to analyze G6pc, Fbp1, and Pck1 gene expressions in two experimental animal models of impaired glucose metabolism. We also evaluated hepatic and renal tissue integrity following Cγ treatment. To generate an insulin resistance model, male Wistar rats were provided 30% sucrose solution ad libitum for 20 weeks. To generate a type 2 diabetes model (STZ), five-day-old rats were intraperitoneally injected with streptozotocin (150 mg/kg). Each animal model was randomized into three subgroups that received the following oral treatments daily for one week: 0.9% w/v NaCl (vehicle; IR-Ctrl and STZ-Ctrl); metformin 300 mg/kg (IR-Met and STZ-Met); and Cγ 150 mg/kg (IR-Cγ and STZ-Cγ). Biochemical parameters were assessed pre- and post-treatment using colorimetric or enzymatic methods. We also performed histological analysis of hepatic and renal tissue. G6pc, Fbp1, and Pck1 gene expressions were quantified using real-time PCR. No histological changes were observed in any group. Post-treatment G6pc gene expression was decreased in the IR-Cγ and STZ-Cγ groups. Post-treatment Fbp1 and Pck1 gene expressions were reduced in the IR-Cγ group but increased in STZ-Cγ animals. Overall, these findings suggest that Cγ is involved in reducing hepatic glucose production, mainly through G6pc inhibition in impaired glucose metabolism disorders. 相似文献
Cassava (Manihot esculenta Crantz) native starch was treated with pyroconversion and enzymatic hydrolysis to produce a pyrodextrin and an enzyme-resistant maltodextrin. Some nutritional characteristics were quantified for both compounds. Pyroconversion was done using a 160:1 (p/v) starch:HCl ratio, 90 °C temperature and 3 h reaction time. The resulting pyrodextrin contained 46.21% indigestible starch and 78.86% dietary fiber. Thermostable α-amylase (0.01%) was used to hydrolyze the pyrodextrin at 95 °C for 5 min. The resulting resistant maltodextrin contained 24.45% dextrose equivalents, 56.06% indigestible starch and 86.62% dietary fiber. Compared to the cassava native starch, the pyrodextrin exhibited 56% solubility at room temperature and the resistant maltodextrin 100%. The glycemic index value for the resistant maltodextrin was 59% in healthy persons. Its high indigestible starch and dietary fiber contents, as well as its complete solubility, make the resistant maltodextrin a promising ingredient for raising dietary fiber content in a wide range of foods, especially in drinks, dairy products, creams and soups. 相似文献
Red beetroot has been ranked among the 10 most potent antioxidant vegetables, although only extraction-based methods have been used to evaluate its total antioxidant capacity. Therefore, the present study aims at comparing the traditional extraction-based method with two more recent approaches (QUENCHER -QUick, Easy, New, CHEap and Reproducible- and GAR -global antioxidant response method), in order to establish their suitability in the case of beetroot. Our results indicate that the total antioxidant capacity of beetroot would be underestimated when using extraction-based procedures, since both QUENCHER and GAR methods resulted in a higher total antioxidant capacity. The effect of a thermal treatment on the total antioxidant capacity of beetroot varies among the methods evaluated and our findings suggest different compounds responsible for the total antioxidant capacity detected in each pre-processing method. Remarkably, the present study demonstrates that the traditional extraction-based method seems useful to screen for (changes in) the “bioavailable” antioxidant potential of the root. 相似文献