scholarly journals Contents of heavy metals in the soil cover in the conditions of technogenesis

2016 ◽  
Vol 5 (1) ◽  
pp. 34-37
Author(s):  
Ivan Victorovich Kazantsev ◽  
Tatyana Borisovna Matveeva
Keyword(s):  
Heavy Metals ◽  
Maximum Permissible Concentration ◽  
Botanical Garden ◽  
X Ray ◽  
Nickel Chromium ◽  
Forest Belts ◽  
Green Zone ◽  
Suburban Forests

The paper examines pollution of soils with heavy metals under technogenic impact. The ways and means of pollutants receipt in soils and their accumulation in soils located in the drainage of railway are described. The role of roadside forest belts on the distribution of pollutants is examined. Determination of heavy metals content in soils was carried out by the x-ray fluorescence method. The results of heavy metal soil pollution in comparison with Clarke value, maximum permissible concentration and regional background levels are represented. The study of heavy metals content was carried out in the soils of right-of-way on the Samara-Syzran section of the Kuibyshev railway, as well as in suburban forests and urban parks of Samara (Botanical garden, Country Park). These areas are exposed to significant anthropogenic impact. Studies have shown that in these areas an increased content of some heavy metals in soils is observed. The main elements present in anthropogenic flows of pollution are copper, nickel, chromium, zinc and lead. This result does not contradict the standard environmental situation. These materials can serve as a basis for further monitoring of suburban forests of Samara green zone and transport facilities

Determination of some heavy metals (Fe, Cu, Zn and Pb) in blood by total reflection X-ray fluorescence

2003 ◽  
Vol 107 ◽  
pp. 203-206 ◽  
Author(s):  
M. Bounakhla ◽  
A. Doukkali ◽  
K. Lalaoui ◽  
H. Aguenaou ◽  
N. Mokhtar ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Total Reflection ◽  
X Ray

scholarly journals Crystallization and X-ray diffraction data analysis of human deoxyhaemoglobin A0 fully stripped of any anions

1999 ◽  
Vol 55 (11) ◽  
pp. 1914-1916 ◽  
Author(s):  
F. A. V. Seixas ◽  
W. F. de Azevedo ◽  
M. F. Colombo
Keyword(s):  
Diffraction Data ◽  
Oxygen Affinity ◽  
X Ray Diffraction ◽  
Structural Explanation ◽  
Human Haemoglobin ◽  
X Ray ◽  
High Resolution Structure ◽  
Allosteric Properties

In this work, initial crystallographic studies of human haemoglobin (Hb) crystallized in isoionic and oxygen-free PEG solution are presented. Under these conditions, functional measurements of the O2-linked binding of water molecules and release of protons have evidenced that Hb assumes an unforeseen new allosteric conformation. The determination of the high-resolution structure of the crystal of human deoxy-Hb fully stripped of anions may provide a structural explanation for the role of anions in the allosteric properties of Hb and, particularly, for the influence of chloride on the Bohr effect, the mechanism by which Hb oxygen affinity is regulated by pH. X-ray diffraction data were collected to 1.87 Å resolution using a synchrotron-radiation source. Crystals belong to the space group P21212 and preliminary analysis revealed the presence of one tetramer in the asymmetric unit. The structure is currently being refined using maximum-likelihood protocols.

Evaluation of computer-controlled SEM in the study of metal-contaminated soils

2003 ◽  
Vol 67 (2) ◽  
pp. 219-231 ◽  
Author(s):  
H. W. Langmi ◽  
J. Watt
Keyword(s):  
Electron Microscopy ◽  
Heavy Metals ◽  
Contaminated Soils ◽  
X Ray ◽  
Computer Controlled ◽  
Weathering Crusts ◽  
Individual Particles ◽  
Element Mapping ◽  
Scanning Electron

Computer-controlled scanning electron microscopy (CCSEM) has been assessed for the determination of form and size distribution of heavy metals in urban contaminated soils. Metal distributions within individual particles were determined using X-ray element mapping. The sites selected for study were (1) around a landfill site, previously a colliery in Wolverhampton, UK and (2) a private garden adjacent to a railway in Nottingham, UK. Backscattered thresholding techniques were used to isolate the Pb-containing categories. The classification results for both Wolverhampton and Nottingham soils were generally similar but more Pb-containing classes were observed for the Nottingham samples when a comparison was made between results of the same size fractions. However, difficulties with the technique arose when particles showing chemically similar weathering crusts were assigned to the same class, despite having different internal compositions. The CCSEM data therefore need to be interpreted with caution and their application limited to situations in which particle internal complexity is not an issue.

scholarly journals Role of Computational Methods in Going beyond X-ray Crystallography to Explore Protein Structure and Dynamics

2018 ◽  
Vol 19 (11) ◽  
pp. 3401 ◽  
Author(s):  
Ashutosh Srivastava ◽  
Tetsuro Nagai ◽  
Arpita Srivastava ◽  
Osamu Miyashita ◽  
Florence Tama
Keyword(s):  
Protein Dynamics ◽  
Computational Methods ◽  
Protein Structures ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
X Ray ◽  
X Ray Crystallography ◽  
Insight Into

Protein structural biology came a long way since the determination of the first three-dimensional structure of myoglobin about six decades ago. Across this period, X-ray crystallography was the most important experimental method for gaining atomic-resolution insight into protein structures. However, as the role of dynamics gained importance in the function of proteins, the limitations of X-ray crystallography in not being able to capture dynamics came to the forefront. Computational methods proved to be immensely successful in understanding protein dynamics in solution, and they continue to improve in terms of both the scale and the types of systems that can be studied. In this review, we briefly discuss the limitations of X-ray crystallography in studying protein dynamics, and then provide an overview of different computational methods that are instrumental in understanding the dynamics of proteins and biomacromolecular complexes.

Concentration and X-ray fluorescence determination of heavy metals on impregnated cellulose filters

2011 ◽  
Vol 47 (15) ◽  
pp. 1619-1622 ◽  
Author(s):  
Z. A. Temerdashev ◽  
Dzh. N. Konshina ◽  
D. I. Salov ◽  
V. V. Konshin
Keyword(s):  
Heavy Metals ◽  
X Ray ◽  
Fluorescence Determination

scholarly journals New insights into the mechanism of substrates trafficking in Glyoxylate/Hydroxypyruvate reductases

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Louise Lassalle ◽  
Sylvain Engilberge ◽  
Dominique Madern ◽  
Pierre Vauclare ◽  
Bruno Franzetti ◽  
...  
Keyword(s):  
Renal Failure ◽  
Active Site ◽  
Ternary Complex ◽  
Substrate Recognition ◽  
Binding Mode ◽  
X Ray ◽  
Hyperoxaluria Type

Abstract Glyoxylate accumulation within cells is highly toxic. In humans, it is associated with hyperoxaluria type 2 (PH2) leading to renal failure. The glyoxylate content within cells is regulated by the NADPH/NADH dependent glyoxylate/hydroxypyruvate reductases (GRHPR). These are highly conserved enzymes with a dual activity as they are able to reduce glyoxylate to glycolate and to convert hydroxypyruvate into D-glycerate. Despite the determination of high-resolution X-ray structures, the substrate recognition mode of this class of enzymes remains unclear. We determined the structure at 2.0 Å resolution of a thermostable GRHPR from Archaea as a ternary complex in the presence of D-glycerate and NADPH. This shows a binding mode conserved between human and archeal enzymes. We also determined the first structure of GRHPR in presence of glyoxylate at 1.40 Å resolution. This revealed the pivotal role of Leu53 and Trp138 in substrate trafficking. These residues act as gatekeepers at the entrance of a tunnel connecting the active site to protein surface. Taken together, these results allowed us to propose a general model for GRHPR mode of action.

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