Search results for "phosphorus"
showing 10 items of 431 documents
Host filtering, not competitive exclusion, may be the main driver of arbuscular mycorrhizal fungal community assembly under high phosphorus
2023
A major goal in ecology is understanding the factors which determine the diversity and distribution of organisms. The outcome of the symbiotic relationship between plants and arbuscular mycorrhizal (AM) fungi is strongly influenced by soil phosphorus (P) availability. Despite this knowledge, there is still much to uncover about how soil P status can shape the taxonomic and phylogenetic assembly of root-colonising AM fungi. Additionally, there is a paucity of understanding about the implications of these changes for the outcome of the AM symbiosis in terms of plant growth, nutrient status and defence traits. We conducted a factorial pot experiment where sorghum (Sorghum bicolor) was grown un…
Zein as biodegradable material for effective delivery of alkaline phosphatase and substrates in biokits and biosensors
2016
A biodegradable material, zein, is proposed as a reagent delivery platform for biokits and biosensors based on alkaline phosphatase (ALP) activity/inhibition in the presence of phosphatase substrates. The immobilization and release of both the substrate and/or the active ALP, in a biodegradable and low-cost material such as zein, a prolamin from maize, and in combination with glycerol as plasticizer have been investigated. Three zein-based devices are proposed for several applications: (1) inorganic phosphorus estimation in water of different sources (river, lake, coastal water and tap water) with a detection limit of 0.2mg/L - compared to at least 1mg/L required by legislation, (2) estimat…
Carbohydrates and Polyols for Energy Supply of the Surgical Patient
1969
The administration of calorie-rich substances to surgical patients pre-,intra- and postoperatively poses many problems.
Importance of Residual Renal Function in Continuous Ambulatory Peritoneal Dialysis: Its Influence on Different Parameters of Renal Replacement Treatm…
1999
<i>Objective:</i> To study the influence of residual renal function (RRF) on different parameters of the renal substitutive treatment offered by peritoneal dialysis. <i>Methods:</i> We analyzed the impact of RRF on dialysis dose, nutrition parameters, anemia and phosphocalcic metabolism in 37 patients with end-stage renal disease (ESRD) treated by continuous ambulatory peritoneal dialysis (CAPD). Analytical controls were done every 6 months after an initial assessment at the end of the first month of treatment. Multiple lineal regression models were used as the statistical method to analyze the influence of RRF on different theoretically dependent factors. RRF was ca…
The effect of dietary phosphorus deficiency on the immune responses of European whitefish (Coregonus lavaretus L.)
2003
Low phosphorous (P) feeds in aquaculture are recommended to reduce eutrophication of water systems. However, the feed should be adequate for normal growth and intact immune defence. Influence of low dietary P supply on non-specific and specific immune defence of European whitefish (Coregonus lavaretus) was studied in two trials. For Trial 1, a semi-purified, low-P diet was formulated and supplied with 0, 2.5, 5.0, 7.5, or 10.0 g P kg(-1)to obtain a P gradient of 4.4-14.9 g kg(-1)diet. Diets were fed to four replicate groups of fingerling whitefish for 42 days in a flow-through, freshwater system maintained at 15 degrees C. Fish fed with the P-unsupplemented diet had significantly lower plas…
Phosphorus-Chalcogen Ring Expansion and Metal Coordination
2017
The reactivity of 4-membered (RPCh)2 rings (Ch = S, Se) that contain phosphorus in the +3 oxidation state is reported. These compounds undergo ring expansion to (RPCh)3 with the addition of a Lewis base. The 6-membered rings were found to be more stable than the 4-membered precursors, and the mechanism of their formation was investigated experimentally and by density functional theory calculations. The computational work identified two plausible mechanisms involving a phosphinidene chalcogenide intermediate, either as a free species or stabilized by a suitable base. Both the 4- and 6-membered rings were found to react with coinage metals, giving the same products: (RPCh)3 rings bound to the…
Modelling biological nitrogen and phosphorus removal with soluble microbial products (SMP) production-degradation processes
2011
Over the last two decades, Membrane Bioreactors (MBR) are increasingly used for wastewater treatment. Mathematical modelling of MBR systems has played a key role in order to better explain the effect of their peculiarities. Indeed, several MBR models have been presented in literature in order to improve the knowledge on MBR systems: biological models, hybrid models which include soluble microbial product (SMP) modelling, physical models able to describe the membrane fouling and integrated models which couple the hybrid models with the physical ones. However, among the existing MBR models only few integrated models have been developed which take into account the existing relationship between…
Chromogenic detection of nerve agent mimics
2008
The current rise in international concern over criminal terrorist attacks via chemical warfare (CW) agents has resulted in an increasing interest in the detection of these lethal chemicals. Among CW species, nerve agents are extremely dangerous and their high toxicity and ease of production underscore the need to detect these deadly chemicals via quick and reliable procedures. A number of detection systems have been developed, most of them based on enzymatic and physical methodologies. However, these usually show limitations such as low selectivity, lack of portability and a certain complexity in their use. An alternative to these classical methods that has been gaining interest in recent y…
Haptotropism in a Nickel Complex with a Neutral, π‐Bridging cyclo‐P4 Ligand Analogous to Cyclobutadiene
2022
The reaction of ( 1 )Ni(η 2 -cod), 2 , incorporating a chelating bis( N -heterocyclic carbene) 1 , with P 4 in pentane yielded the dinuclear complex [( 2 )Ni] 2 (μ 2 ,η 2 :η 2 -P 4 ), 3 , formally featuring a cyclobutadiene-like, neutral, rectangular, π-bridging P 4 -ring. In toluene, the butterfly-shaped complex [( 1 )Ni] 2 (μ 2 ,η 2 :η 2 -P 2 ), 4 , with a formally neutral P 2 -unit was obtained from 2 and either P 4 or 3 . Computational studies showed that a low energy barrier haptotropic rearrangement involving two isomers of the μ 2 ,η 2 :η 2 -P 4 coordination mode and a low energy μ 2 ,η 4 :η 4 -P 4 coordination mode, as previously predicted for related nickel cyclobutadiene complexes…
Benson group additivity values of phosphines and phosphine oxides: Fast and accurate computational thermochemistry of organophosphorus species
2018
Composite quantum chemical methods W1X-1 and CBS-QB3 are used to calculate the gas phase standard enthalpy of formation, entropy, and heat capacity of 38 phosphines and phosphine oxides for which reliable experimental thermochemical information is limited or simply nonexistent. For alkyl phosphines and phosphine oxides, the W1X-1, and CBS-QB3 results are mutually consistent and in excellent agreement with available G3X values and empirical data. In the case of aryl-substituted species, different computational methods show more variation, with G3X enthalpies being furthest from experimental values. The calculated thermochemical data are subsequently used to determine Benson group additivity …