Search results for "Dative"
showing 10 items of 2381 documents
Increased conformational rigidity of humic substances by oxidative biomimetic catalysis
2005
A synthetic water-soluble meso-tetra(2,6-dichloro-3-sulfonatophenyl)porphyrinate of iron(III) chloride, Fe(TDCPPS)Cl, was employed as a biomimetic catalyst in the oxidative coupling of terrestrial humic materials. High-performance size-exclusion chromatography (HPSEC), solid-state nuclear magnetic resonance (CPMAS-(13)C NMR), electron paramagnetic resonance (EPR), and diffuse reflectance infrared spectroscopy (DRIFT) were used to follow conformational and structural changes brought about in different humic materials by the oxidative coupling. Increase in apparent weight-average molecular weight (Mw(a)) occurred invariably for all humic substances with the oxidative polymerization catalyzed …
Evidence of oxidative stress in very long chain fatty acid--treated oligodendrocytes and potentialization of ROS production using RNA interference-di…
2011
X-linked adrenoleukodystrophy (X-ALD) and pseudo neonatal adrenoleukodystrophy (P-NALD) are neurodegenerative demyelinating diseases resulting from the functional loss of the peroxisomal ATP-binding cassette transporter D (ABCD1) and from single peroxisomal enzyme deficiency (Acyl-CoA oxidase1: ACOX1), respectively. As these proteins are involved in the catabolism of very long chain fatty acids (VLCFA: C24:0, C26:0), X-ALD and P-NALD patients are characterized by the accumulation of VLCFA in plasma and tissues. Since peroxisomes are involved in the metabolism of reactive oxygen species (ROS) and nitrogen species (RNS), we examined the impact of VLCFA on the oxidative status of 158N murine o…
Increased susceptibility of microcytic red blood cells to in vitro oxidative stress.
1995
Oxidative damage to erythrocytes in thalassaemia has been related to generation of free radicals by an excess of denaturated alpha- or beta-globin chains, intracellular iron overload and low concentration of normal haemoglobin (HGB). Two good indicators of such oxidative damage are the high red blood cell (RBC) malonyldialdehyde (MDA) production detected following exogenous oxidant stress and the decrease of pyrimidine 5'-nucleotidase (P5N), the most sensitive enzyme to SH-group damage in vivo. Conflicting data, however, have so far accumulated in the literature concerning differences in oxidative damage between the different forms of thalassaemia and iron deficiency anaemia (IDA). In the p…
The impact of copper ions on oxidative stress in garden cress Lepidium sativum
2017
Normal oxygen metabolism is an endogenous source of reactive oxygen species (ROS). The source of ROS are also many environmental factors including heavy metals. In certain concentration range, the presence of ROS is necessary to maintain proper cell function. Thus, cells have many mechanisms, which role is focused on maintaining a constant concentration of ROS. Imbalance between the formation of ROS and action of a protective antioxidant system leads to oxidative stress. This may results with a damage to the structure of proteins, lipids and nucleic acids, which in turn can lead to disturbances in the functioning of the cell and even to the death. The aim of the study was to evaluate the ef…
Crystal structure ofcis-1-phenyl-8-(pyridin-2-ylmethyl)dibenzo[1,2-c:2,1-h]-2,14-dioxa-8-aza-1-borabicyclo[4.4.0]deca-3,8-diene
2017
The present work describes the synthesis and crystal structure of the new B-phenyloxazaborocine, C26H23BN2O2. The title compound adopts a zwitterionic form with a significant intramolecular N→B dative bond and intermolecular C—H⋯O interactions connecting molecules parallel to the b axis.
On the mechanistic behavior of highly efficient palladium-tetraphosphine catalytic systems for cross-coupling reactions: first spectroscopic and elec…
2008
Electrochemical studies carried out in conjunction with 31P NMR spectroscopy on the palladium(II)/palladium(0) halogeno complexes of the tetraphosphine 1,1′,2,2′-tetrakis(diphenylphosphino)-4,4′-di...
Feeding Dairy Ewes with Fresh or Dehydrated Sulla (Sulla coronarium L.) Forage. 1. Effects on Feed Utilization, Milk Production, and Oxidative Status
2022
Feeding dairy ewes with fresh sulla forage (FSF), a legume species containing condensed tannins (CT), has been shown to increase feed intake, milk yield, and casein and enhances the oxidative status of animals. Dehydration of FSF could be an alternative to hay-making to preserve the nutritional properties. This research aimed to compare the responses of dairy ewes fed with diets based on sulla hay (SH), pelleted dehydrated sulla forage (DSF), or FSF in terms of efficiency of feed utilization, milk production, and the balance between oxidant (reactive oxygen metabolites (ROMs)) and antioxidant (biological antioxidant potential (BAP)) substances at the plasma level. Ten first-lambing (FL) and…
Enhanced Lipid Peroxidation and Platelet Activation in the Early Phase of Type 1 Diabetes Mellitus
2003
Background— To investigate early events possibly related to the development of diabetic angiopathy, we examined whether 8-iso-prostaglandin F 2α (8-iso-PGF 2α ) formation, a marker of in vivo oxidant stress, is altered in different stages of type 1 diabetes (T1DM) and whether it correlates with the rate of thromboxane (TX) A 2 biosynthesis, a marker of in vivo platelet activation. We also investigated the relationship between inflammatory markers and F 2 -isoprostane formation in this setting. Methods and Results— A cross-sectional study was performed in 23 insulin-treated patients aged <18 years with new-onset T1DM (≤6 weeks, group A), matched for age and gender with 23 patients with s…
Oxidative Stress and Inflammatory Biomarkers in Patients with Diabetic Foot
2022
Background and Objectives: Diabetic foot (DF) development is driven by complex interactions of hyperglycemia, inflammation, and oxidative stress (OS). We aimed to investigate OS and inflammatory biomarkers in patients with DF and their potential to improve early diagnosis and management of DF. Materials and Methods: The prooxidant–antioxidant balance (PAB), superoxide dismutase (SOD), total oxidative status (TOS), total sulfhydryl groups (SHG), routine biochemical parameters, and complete blood count were determined in 42 patients with type-2 DM, of which 23 patients had DF, while 19 patients were without DF complications. The neutrophils-to-lymphocyte ratio (NLR) was evaluated as a b…
An easy access to fused chromanones via rhodium catalyzed oxidative coupling of salicylaldehydes with heterobicyclic olefins
2016
Abstract Herein we describe a detailed study on the rhodium catalyzed oxidative coupling of salicylaldehydes with heterobicyclic olefins such as diazabicyclic olefins and urea-derived bicyclic olefins. The developed method provides an ideal route to fused chromanone systems in a single synthetic step. Moreover, the scope of this methodology was extended to different oxa/aza-bridged bicyclic urea derivatives.