Theoretical chemical characterization of phosphate-metal-humic complexes and relationships with their effects on both phosphorus soil fixation and phosphorus availability for plants

BACKGROUND: Previous studies showed that phosphate can be complexed by humic acids (HA) through stable metal (M) bridges (PMHA). We studied the thermodynamic properties of PMHA and their relationships with the ability of PMHA to both decrease soil P fixation and increase P availability for plants. With this aim, we studied the theoretical stability of PFeHA, PAlHA and PCaHA by molecular modelling methods in relation to the degree and intensity of P absorption in soils and the ability of plants to take up complexed P. RESULTS: A density functional theory (DFT) quantum chemical study enabled us to obtain stable structures for the three PMHA complexes in water solution. The theoretical stabilities (ΔG⁰) were consistent with that for apparent stability obtained by Scatchard method, PFeHA ≥ PAlHA > PCaHA, though the differences were clearer by the DFT method. Also the reduction of soil P fixation and the release of P from PMHA in the presence of an anionic resin confirmed the stability order of the different PMHA. Plant studies confirmed the ability of diverse plant species to take up both P and metal complexed in PMHA. CONCLUSION: The results indicated the potential efficiency of PMHA‐based fertilizers to optimize P fertilization for crops cultivated in soils with high P fixation ability. Copyright © 2012 Society of Chemical Industry     

Enhancing antioxidant availability in wheat grains from plants grown under seawater stress in response to microalgae extract treatments

BACKGROUND: The present study was designed to investigate the enhanced antioxidant capacity of whole grains from wheat plants grown under seawater stress in response to microalgae extract treatment. RESULTS: The total carotenoid (TCAR), tocopherol (TOC), phenolic (TPC), and protein (PC) contents in whole grains of wheat plants irrigated with 10% and 20% (v/v) seawater (SW) in response to water extracts of microalgae Spirulina maxima (SME) and Chlorella ellipsoida (CEE) as well as exogenous plant growth enhancers of ascorbic acid and benzyladenine treatments were measured. The results showed that the levels of enhanced TCAR (range 0.08–0.14 g kg^?1), TOC (range 0.05–0.12 g kg^?1), TPC (range 0.80–2.96 g kg^?1) and PC (range 93.4–137.9 g kg^?1) in wheat grains of plants irrigated with 10% and 20% SW were significantly increased in response to SME and CEE treatments. Evaluation of antioxidant activity of ethanolic extracts of grains of SW‐stressed plants indicated that DPPH and TBAS radical scavenging activity was significantly increased in response to SME and CEE treatments and coincided with the increase in levels of antioxidant compounds present in each extract. The electrophoretic profiles of the grains of proteins of treated samples exhibited quite different patterns from those in control samples. CONCLUSION: The results suggest that the application of algal extracts to wheat plants irrigated with SW is useful for improvement of salinity tolerance. This effect can be triggered by the stimulation of antioxidant components and protein content. Copyright © 2009 Society of Chemical Industry     

The availability to pasture plants of native and applied soil cobalt in relation to extractable soil cobalt and other soil properties

In pot trials using a range of soils from South-East Scotland, plant cobalt concentrations were significantly correlated with the amounts of cobalt extracted from soil with 0.05 M calcium chloride. Plant cobalt concentrations were also correlated with soil pH, showing a decrease with increasing soil pH. There were no significant correlations between plant cobalt concentrations and 0.5 M acetic acid-extractable cobalt, 0.04 M EDTA-exttactable cobalt, isotopically exchangeable cobalt or total soil cobalt. Uptake of cobalt by ryegrass from cobalt added to the soil was inversely related to both the ability of the soil to sorb cobalt and to soil pH.     

Nutrient variation and availability of wheat DDGS,corn DDGS and blend DDGS from bioethanol plants

BACKGROUND: The dramatic increase in bioethanol production in Canada has resulted in millions of tonnes of different types of new co‐products: wheat dried distillers grains with solubles (DDGS), corn DDGS and blend DDGS (e.g. wheat:corn=70:30). There is an urgent need to systematically evaluate the nutritive value of different types of DDGS. Little research has been conducted to determine the magnitude of the differences in nutritive value among wheat DDGS, corn DDGS and blend DDGS and between different bioethanol plants. The objectives of this study were to compare different types of DDGS and different bioethanol plants in terms of: (1) chemical profiles; (2) mineral concentrations of sulfur (S), calcium (Ca) and phosphorus (P); (3) protein and carbohydrate subfractions associated with different degradation rates; (4) digestible component nutrients and energy values; and (5) in situ rumen availability of each DDGS component. RESULTS: The results showed that chemical profiles differed among wheat DDGS, corn DDGS and blend DDGS. Mineral profiles were different among the three types of DDGS with wheat DDGS lower in S (3.9 vs. 7.2 g kg^?1 DM), higher in Ca (1.8 vs. 0.5 g kg^?1 DM) and P (9.1 vs. 7.7 g kg^?1 DM) than corn DDGS, but similar to blend DDGS. Wheat DDGS had the lowest and corn DDGS had the highest energy values (TDN, DE_3X, ME_3X, NEL_3X for dairy; NE_m and NE_g beef cattle) while blend DDGS was in between. Wheat DDGS was lower in the intermediately degradable CP fraction (PB2: 277 vs. 542 g kg^?1 CP) and higher in the rapidly non‐protein degradable fraction (163 vs. 114 g kg^?1 CP) and slowly degradable CP fraction (PB3: 512 vs. 279 g kg^?1 CP) than corn DDGS, but similar to blend DDGS. For carbohydrate subfractions, wheat DDGS was higher in non‐structural carbohydrate fraction (NSC: 483 vs. 184 g kg^?1 CHO), higher in highly degradable free sugars fraction (CA: 359 vs. 91 g kg^?1 CHO), higher in unavailable CHO (CC: 204 vs. 142 g kg^?1 CHO), similar in rapidly degradable CHO fraction (average 108 g kg^?1 CHO), lower in intermediately degradable CHO (CB2: 313 vs. 674 g kg^?1 CHO) than corn DDGS. Wheat DDGS had higher in situ CP degradability and lower NDF degradability than corn DDGS, but similar degradability to blend DDGS. CONCLUSION: Among the three types of DDGS, they differed in chemical characterisation, mineral concentration (S, Ca, P), estimated energy values for both beef and dairy cattle, protein and carbohydrate subfractions, in situ degradability. Bioethanol plants also had significant impact on nutritive value of DDGS. The energy values (DE_3X, ME_3X, NEL_3X, NE_m and NE_g) in wheat DDGS were similar to wheat and corn suggesting wheat DDGS as an alternative to wheat and corn in dairy and beef diets. The energy values (DE_3X, ME_3X, NEL_3X, NE_m and NE_g) in corn DDGS were significantly higher than in corn, indicating that corn DDGS is superior to corn in dairy and beef diets. The energy values (DE_3X, ME_3X, NEL_3X, NE_m and NE_g) in the blend DDGS were higher than that in wheat DDGS but similar to corn DDGS, suggesting blend DDGS as an alternative to corn and superior to wheat and wheat DDGS in dairy and beef diets. Copyright © 2009 Society of Chemical Industry     

Cd and Zn uptake kinetics in Daphnia magna in relation to Cd exposure history

The uptake kinetics of Cd and Zn in a freshwater cladoceran Daphnia magna after exposure to different concentrations of Cd for various durations was quantified. The accumulated Cd concentrations increased with ambient Cd concentration and exposure duration. As a detoxification mechanism, metallothioneins (MTs) were induced when the Cd preexposure condition was beyond the noneffect threshold. The MT induction was dependent on both Cd concentration and duration of preexposure. Increasing the Cd exposure concentration to 20 microg L(-1) for 3 d caused a 44% reduction in Cd assimilation efficiency (AE, the fraction assimilated by the animals after digestion) by the daphnids from the dietary phase, but a 2.4-fold increase in Zn AE. Generally, the dissolved metal uptake rate was not significantly affected by the different Cd preexposure regimes, except at a much higher Cd concentration (20 microg L(-1)) when the Zn influx was enhanced. Significant effects from Cd exposure on the ingestion rate of the daphnids were also observed. When the MT synthesis was not coupled with the accumulated Cd tissue burden (e.g., a delay in MT synthesis), apparent Cd toxicity on the feeding behavior and the Cd AE was observed, thus highlighting the importance of MTs in modifying the metal uptake kinetics of D. magna. Overall, daphnids responded to acute Cd exposure by reducing their Cd AE and ingestion, whereas they developed a tolerance to Cd following chronic exposure. The bioavailability of Zn was enhanced as a result of Cd preexposure. This study highlights the important influences of Cd preexposure history on the biokinetics and potential toxicity of Cd and Zn to D. magna.     

提高木片质量的途径

高品质的木片不但意味着很高的木片合格率,而且还应包括高的木片均匀度、低的切损率和含杂率等指标.本文对提高木片质量在设备改进、工艺优化上的一些可行途径进行了探讨.     

Macrolevel approaches to improve the availability of complementary foods

Large numbers of infants and young children suffer from the short- and long-term health effects of poor breastfeeding and complementary feeding practices. Strategies to improve the availability of and access to low-cost fortified complementary foods can play an important corresponding role to that of behavior change in improving nutritional status of young children. However, the nutritional quality of complementary foods used in publicly funded programs is not always optimal, and such programs are costly and reach only a tiny fraction of those who could benefit. To broadly reach the target population, such foods need to be commercially available at affordable prices and promoted in a way that generates demand for their purchase. A sensible long-term policy for the promotion of low-cost fortified complementary foods calls for attention to their nutritional formulations and cost, the economics of production, and the legislative, regulatory, and competitive framework in which marketing occurs. This paper provides information on how to improve the nutritional formulations of fortified complementary foods and outlines the necessary conditions for a market approach to their production and promotion.     

意大利纺机销售持续回暖

2006年起，意大利纺机销售开始回升，出口起到主要拉动作用；今年上半年，意大利国内纺机市场需求表现火爆。目前，意大利纺机在技术创新型纺织生产设备领域占据着重要地位，82％的欧洲纺企．47％的亚洲纺企在使用意大利生产的此类产品。[编者按]     

改造蒸发系统提高制盐产量

简述了利用原有的真空制盐基础设施,通过对真空制盐蒸发系统的工艺、设备进行技术改造,提高真空制盐产量.     

Nutritional supplements to increase muscle mass.

Although nutritional supplements purported to increase muscle mass are widely available at health food stores, gyms, by mail order, and over the Internet, many of these supplements have little or no data to support their claims. This article reviews the theory and research behind popular nutritional supplements commonly marketed as muscle mass builders. Included are the minerals chromium, vanadyl sulfate, and boron, the steroid hormone dehydroepiandrosterone (DHEA), beta-methyl-hydroxy-beta-methylbutyrate (HMB), creatine, protein supplements, and amino acids. Research has shown that chromium vanadyl sulfate, and boron do not appear to be effective in increasing lean body mass. The few studies examining DHEA have not supported the claim of increased muscle gain. Preliminary work on HMB supports an anticatabolic effect, but only one human study is currently available. Many studies reported increased body mass and several have reported increased lean body mass following creatine ingestion. This weight gain is most likely water retention in muscle but could also be due to some new muscle protein. Although athletes have a greater protein requirement than sedentary individuals, this is easily obtained through the diet, negating the use of protein supplements. Studies on amino acids have not supported their claim to increase growth hormone or insulin secretion. Nutritional supplements can be marketed without FDA approval of safety or effectiveness. Athletes who choose to ingest these supplements should be concerned with unsubstantiated claims, questionable quality control, and safety of long-term use.     

Nitrogen availability drives the effect of Glomus intraradices on the growth of strawberry (Fragaria x ananassa Duch.) plants

BACKGROUND: On the one hand, the critical nitrogen (N) content curve allows the minimal N content necessary for maximum growth rate at any stage of crop development to be predicted. On the other hand, arbuscular mycorrhizal fungi (AMF) transfer N from the soil to the plants and its growth and activity depends on the availability of soil N. Our objective was to investigate how the availability of N in the soil affects growth and the accumulation of N in inoculated strawberry plants. Root colonisation, dry matter accumulation and the critical N% curve were studied during growth of inoculated and non‐inoculated strawberry plants grown at several N levels. RESULTS: (1) The increase in the availability of N augmented root colonisation by AMF. (2) The effect of AMF on plant growth depended on N availability and the plant developmental status. (3) The critical %N curves were fitted by the following equations: %N = 2.81× (DM)^−0.21 (r² = 0.81) and %N = 2.89× (DM)^−0.32 (r² = 0.80) for inoculated and non‐inoculated plants, respectively (where DM is the weight of leaf dry matter, in g plant⁻¹). CONCLUSION: N availability was a key factor for root colonisation by AMF and for its contribution to plant growth. The patterns of the critical %N curves suggest that AMF modified the photosynthetic N use efficiency. Copyright © 2012 Society of Chemical Industry     

Aging effects on the availability of herbicides to runoff transfer

Realistic estimation of sorption parameters is essential to predict long-term herbicide availability in soils and their contamination of surface water and groundwater. This study examined the temporal change of an effective partition coefficient Kd(eff) for the herbicides simazine, diuron, and oryzalin from a 0.12 ha field experiment during 7 vineyard growing seasons. Kd(eff) is the ratio of solvent extractable herbicide concentrations in the top soil (0-2 cm) to the average concentrations in runoff water and is considered to assess the effective availability of herbicides to runoff transfer. Kd(eff) increased largely with aging time since application, from values similar to those of the literature (determined in 24 h batch conditions, Kd(ref)), up to 88, 164, and 30 times these initial values for simazine, diuron, and oryzalin respectively. The seasonal variation of Kd(eff) values between years and compounds could be adequately described by a unique model, taking into account the cumulative rainfall since application and Kd(ref) of each compound. This simple model was able to represent the influence of the soil moisture content and its changes in the different biological and physicochemical processes that may contribute to the (bio)available, sorbed, or entrapped state of any of the studied herbicides with aging time under Mediterranean climate.     

Diets rich in starch increase the posthepatic availability of amino acids in dairy cows fed diets at low and normal protein levels

Five mid-lactation multicatheterized Jersey cows were used in a 4 × 4 Latin square design to investigate whether the increase in milk N yield associated with diets rich in starch versus fiber could originate from changes in the splanchnic AA metabolism and if these changes depended upon the dietary crude protein (CP) content. Four isoenergetic diets were formulated to provide 2 different carbohydrate compositions [diets rich in starch (350 g of starch and 310 g of neutral detergent fiber/kg of dry matter) versus rich in fiber (45 g of starch and 460 g of neutral detergent fiber/kg of dry matter)] crossed by 2 different CP contents (12.0 vs. 16.5% CP). At the end of each treatment period, 6 hourly blood samples were collected from the portal and hepatic veins as well as the mesenteric artery to determine net nutrient fluxes across the portal-drained viscera (PDV), liver, and total splanchnic tissues. Dry matter and calculated energy intake as well as total absorbed energy were similar across treatments. However, the net portal appearance (NPA) of acetate, total volatile fatty acids, and β-hydroxybutyrate were higher with diets rich in fiber versus starch, whereas that of oxygen, glucose, butyrate, and insulin were lower. Concomitant to these changes, the percentage of N intake recovered as total AA (TAA) in the portal vein was lower for diets rich in fiber versus starch (42.3 vs. 51.4%, respectively), without, however, any difference observed in the NPA of the main AA used as energy fuels by the PDV (Glu, Gln, and Asp). Despite a higher NPA of TAA with starch versus fiber diets, no differences in the net hepatic flux of TAA, essential and nonessential AA were observed, resulting in a higher (+22%) net splanchnic release of AA and, hence, a greater (+7%) milk N yield. The net hepatic flux and hepatic fractional removal of none of the individual AA was affected as the main carbohydrate changed from fiber to starch, except for Gly and Lys, which were higher for the latter. After correcting for differences in NPA of TAA, the net hepatic uptake of TAA tended to be lower with starch versus fiber diets. The higher transfer of N from feed to milk with diets rich in starch is not the consequence of a direct sparing AA effect of glucogenic diets but rather the result of lower energy requirements by the PDV along with a higher microbial N flow to the duodenum. A better AA use by peripheral tissues with starch versus fiber diets was also hypothesized but more studies are warranted to clarify this issue.     

怎样提高白纸板的挺度

通过配用BCTMP浆、添加层间喷雾淀粉等措施，能够提高白纸板的挺度。     

促进肉制品安全增强国际竞争力

肉制品生产安全技术升级 2004年7月,国家"十五"攻关课题"冷却肉加工关键技术研究与新产品开发"和"发酵肉制品加工关键技术研究与新产品开发"项目在中国农业大学通过了专家鉴定.这两项技术的研制成功将改变我国肉制品品种数量少,保存时间短,质量稳定性差的现状,使肉制品的加工生产产业化、规模化."冷却肉加工关键技术研究与新产品开发"技术的生产工艺流程和质量管理体系、冷却肉综合保鲜、护色和包装技术、冷却肉汁液流失控制技术均达到了国际先进水平."发酵肉制品加工关键技术研究与新产品开发"实现了肉用优良微生物菌种的筛选、发酵剂的研制与产业化开发、发酵肉制品加工工艺与新产品开发等公关研究,为今后发酵肉制品在我国的发展打下了良好的应用基础.