ESR Method Research Articles

Comparison of alternate erythrocyte sedimentation rate measurement by automated Celltac α+ (MEK 1305) and reference Westergren method

Objectives: Manual Westergren method is routinely used for ESR measurement; however, it has many limiting factors which include inherent and technical factors. Alternate/modified Westergren methods have been devised to overcome the limitations of the manual Westergren method. These new methods must be properly evaluated before introducing in clinical laboratories. Material and Methods: A total of 350 randomly collected Ethylene Diamine Tetraacetic Acid (EDTA) samples from hospitalized and ambulatory patients were assayed parallelly in the recently launched Hematology Analyzer Celltac α+ (MEK 1305) and manual Westergren method. Results of these assays were subjected to statistical analysis using a coefficient of correlation, Passing-Bablok regression, and the Bland-Altman statistical methods and the results of the present study were also compared with 16 selected similar studies published in the past 22 years. Intrarun precision using patient samples and inter-run precision using manufacturer’s controls (MEK-3DN and MEK-3DL) were also determined. Results: The present study revealed a Pearson correlation of 0.9058, mean bias of −6.43, and limits of agreements 17.5–−30.4, between Celltac α+ (MEK 1305) and the reference Westergren method. Intrarun precision using patient samples yielded a coefficient of variation ranging from 0% to 14% and inter-run precision using commercial controls yielded a CV of 9.32% for abnormal (MEK-3DL) control and 13.6% for normal level control (MEK-3DN). Conclusion: With good correlation between Celltac α+ (MEK 1305) and the reference Westergren method, acceptable bias, and limits of agreements, automated Celltac α+ (MEK 1305) with its additional advantages is a valid substitute for the reference ESR method in clinical laboratories.

The Chronology of Early Human Settlement in Three Gorges Region, China—Contribution of Coupled Electron Spin Resonance and Uranium-Series Dating Method

The Three Gorges region (TGR) located in the geographic center of China, is a transition zone between mountain and plain areas, and a probable migration corridor for hominins and other mammals between South and North China. Detailed chronological information of paleoanthropological evidence in this area could help us better understand the human evolution in East Asia. The OSL and U-series dating methods are two conventional dating methods generally adopted to date such sites; however, their applications were limited by the dating range—restricted to several hundred of millennia and ambiguous stratigraphic relationship between the archaeological remains and the dating target materials. Cosmogenic nuclide burial dating of quartzite stone artifacts and coupled electron spin resonance and uranium series dating (ESR/U-series) of fossil teeth have the potential to date Early–Middle Pleistocene hominin sites in Asia and were applied increasingly in China in recent years. However, the application of cosmogenic 26Al/10Be burial dating is limited in TGR because most sites are dominated by limestone, leading to the scarcity of the quartz component. In this case, the coupled ESR/U-series method plays a more important role in the establishment of the chronology of human settlement. In TGR, by using the coupled ESR/U-series method, we have dated seven important Early and Middle Pleistocene hominin settlement sites, including Longgupo, Jianshi, Yunxian, Meipu, Bailongdong, Changyang, and Yumidong sites. Based on our dating results, we propose that hominins were settled in TGR probably from the early stage of Early Pleistocene (∼2.5−2.2 Ma) at the Longgupo site to the late Middle Pleistocene to Late Pleistocene of the Yumidong site (∼274−14 ka) and very likely to spread to other parts of East Asia during this time period. In view of the potential of coupled ESR/U-series dating on fossil teeth from the hominin sites in the TGR, future work may consider the micro damage or non-destructive analysis of enamel fragment with the ESR method and laser ablation ICP-MS techniques that will make possible the direct dating of precious human fossils in China.

Los Villares locality (Ruidera, Castilla-La Mancha, Spain): a new Middle Pleistocene fossil assemblage from the Southern Iberian Plateau with possible evidence of human activity

We present the discovery of a Middle Pleistocene fossil assemblage at Los Villares (Ruidera, Ciudad Real, Castilla-La Mancha), which has possible evidence of associated human activity. The potential of the site has been evaluated through multidisciplinary research including taxonomy, anatomy, deep learning, and direct dating of fossil remains. A surface study carried out in 2017, over a very limited area (2 m2) on the slope of one of the Ruidera lakes led to the discovery of more than 50 fossil specimens, including cranial (mainly teeth) and postcranial remains. This rich assemblage is dominated by the remains of Caprinae, although the presence of some small or medium carnivore remains also stands out. The identification of a cut mark, tested with Convolutional Neural Networks, suggests the presence of human activity within the bone assemblage. Several fossils were directly dated using a multi-technique approach involving radiocarbon, U-Th, and ESR methods. The results constrain the fossil assemblage to between 300 ka and 400 ka, positioning Los Villares as one of the first Middle Pleistocene localities identified in the Upper Guadiana basin, on the Southern edge of the Southern Iberian Plateau. These promising initial results show the great potential of the site to contribute to filling a gap of knowledge in the Pleistocene archaeo-paleontological record of the Iberian Peninsula. Nevertheless, we also acknowledge the need for systematic excavations in the future, not only to obtain a better idea of the lateral and stratigraphic extension of the fossil assemblage and its complete taxonomic composition but to confirm the human presence at the site.

Immobilization of bismuth oxychloride on cellulose nanocrystal for photocatalytic sulfonylation of arylacetylenic acids with sodium arylsulfinates under visible light

As an ideal matrix material, cellulose nanocrystal (CNC) has abundant hydroxyl groups and high specific surface area, which are beneficial to construct oxygen vacancies in BiOCl and achieve high dispersion of BiOCl on the surface of the matrix. Herein, we used a facile method to prepare a kind of BiOCl/CNC composite, which exhibited excellent visible light catalytic performance and recyclability in the preparation of arylacetylene sulfones. • A Stable and efficient BiOCl/CNC photocatalytic composite was prepared. • The CNC is conducive to the establishment of oxygen vacancies of BiOCl/CNC. • BiOCl/CNC had a good photocatalytic performance in the sulfonylation reaction. As a promising semiconductor photocatalyst, BiOCl has been widely used in the field of environmental protection. However, due to its weak ability to absorb visible light, the application of BiOCl in other important photocatalytic fields has been significantly limited, such as organic synthesis. In this work, a facile method was used to prepare a highly efficient heterogeneous nano-photocatalyst BiOCl/cellulose nanocrystal (CNC). Subsequently, the BiOCl/CNC was verified by XPS, ESR, BET and other characterization methods. The results show that not only the strong interaction between BiOCl and CNC increases the visible light absorption intensity of the composite, but also the combination of BiOCl and CNC makes the specific area of the catalyst more than twofold. In addition, a large number of hydroxyl groups contained in CNC can be combined with the B O bond in BiOCl through hydrogen bonds, forming abundant oxygen vacancies on BiOCl/CNC. Excitedly, these changes enable BiOCl/CNC to exhibit excellent photocatalytic performance and regeneration performance in the sulfonation reaction of arylacetylene acid and sodium arylsulfinate, with a yield of up to 96%. This work represents a step towards a low-cost, environmentally friendly composite of cellulose and BiOCl, which will provide useful enlightenment for future exploration in related fields.

ESR dating of optically bleached quartz grains from Plio-Pleistocene to Holocene coastal dune deposits (Wilderness-Knysna area, South Africa): a comparison with luminescence

Five Plio-Pleistocene to Holocene aeolian quartz samples from the coastal dune deposits of the Wilderness-Knysna area (South Africa) previously dated by OSL were selected for ESR dating. Samples were processed following the Multiple Centre approach and using the Multiple Aliquot Additive dose method. Aluminium (Al) and Titanium (Ti) signals were systematically measured in all samples. Our study shows that ESR results obtained for Middle Pleistocene to Holocene samples may be strongly impacted by (i) the presence of a significant high frequency noise in the ESR spectra acquired for the Ti signals and (ii) the choice of the fitting function employed. In particular, if not taken into account, very noisy spectra can lead to a significant overestimation of the true ESR intensity measured for the Ti–H signal. These sources of uncertainty are however not sufficient to remove the ESR age overestimations. Consequently, our results indicate that the Al and Ti ESR signals of these quartz samples have not been fully reset during their aeolian transport. While this work contributes to improve our understanding of the ESR method applied to quartz grains, and especially of the potential and limitations of the Ti signals, it also provides additional baseline data to illustrate the existing variability among quartz samples of different origins or sedimentary context. Our results are consistent with previous studies by confirming that the Ti–H signal shows the best potential for the evaluation of low dose values (<100 Gy for these samples), whereas it becomes inappropriate for the higher dose range, and the Ti–Li–H (option D sensu Duval and Guilarte, 2015) should be used instead. Beyond the methodological outcome, this ESR dating study also provides a useful addition to the existing chronology of the aeolian deposits in this region. In particular, new (and possibly) finite numerical age results were obtained for the two oldest samples, constraining the aeolianite landward barrier dune and the coversand formations to the MIS 10-8 and Pliocene, respectively.

Mechanochemical synthesis and structure of a nanocluster {organosilicon dendrimer - Copper dimer}

A novel nanocluster (organosilicon dendrimer - copper dimer) G1–8S-Dec•2CuCl2 was synthesized by a mechanochemical method. Optical and IR spectroscopy, NMR and ESR methods confirm that mechanochemical action on the mixture (dendrimer G1–8S-Dec + anhydrous copper (II) chloride) leads to the formation of a structure in which two copper atoms are linked by exchange interaction and are stabilized in the form of a dimer by sulfur atoms in the structure of the dendrimer G1–8S-Dec. A quantum mechanical calculation was carried out using the density differential method (DFT), which proved the possibility of the existence of two tetrahedral complexes SCuCl3 connected by a common face of chlorine atoms and having sulfur atoms at the vertices located in the branches of the dendrimer. The structure of the Cu2Cl4Si5C116H244S8 nanocluster is calculated by complete geometry optimization. It was found that the synthesized cluster implements the Dzyaloshinsky - Moriya interaction and exhibits multiferroic properties.

A novel model to assess disease activity in Takayasu arteritis based on 18F-FDG-PET/CT: a Chinese cohort study.

To investigate the utility of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG-PET/CT) in assessing disease activity in Takayasu arteritis (TA). Ninety-one patients with TA were recruited from a Chinese cohort. Clinical data, acute-phase reactants and 18F-FDG-PET/CT findings were simultaneously recorded. The value of using 18F-FDG-PET/CT to identify active disease was evaluated, using ESR as a reference. Disease activity assessment models were constructed and concordance index (C-index), net reclassification index (NRI), and integrated discrimination index (IDI) were evaluated to compare the benefits of the new modes with ESR and the Kerr score. In total, 64 (70.3%) cases showed active disease. Higher levels of ESR and CRP, and lower IL-2 receptor (IL-2R) levels were observed in active cases. 18F-FDG-PET/CT parameters measured by determining the standard uptake value (SUV), including SUVmean, SUVratio1, SUVratio2, sum of SUVmean and sum of SUVmax, were significantly higher in active disease groups. The C-index threshold of ESR to indicate active disease was 0.78 (95% CI: 0.69, 0.88). The new activity assessment model combining ESR, sum of SUVmean and IL-2R showed significant improvement in C-index over the ESR method (0.96 vs 0.78, P < 0.01; NRI 1.63, P < 0.01; and IDI 0.48, P < 0.01). The new model also demonstrated modest superiority to the Kerr score assessment (0.96 vs 0.87, P = 0.03; NRI 1.19, P < 0.01; and IDI 0.33, P < 0.01). A novel 18F-FDG-PET/CT-based method that involves combining the sum of SUVmean with ESR score and IL-2R levels demonstrated superiority in identifying active TA compared with conventional methods.

High-performance ethanol sensor of wrinkled microspheres by spray pyrolysis

Different morphologies of In2O3 were synthesized by ultrasonic spray using InCl3 and In(NO3)3 as precursors. The samples using In(NO3)3 as a precursor exhibited more excellent gas sensing performance compared with InCl3. Furthermore, different molar ratios of Sb were introduced to study the influence of Sb concentration on gas sensing performance of In2O3 microspheres. All samples have been tested by SEM, TEM, ESR and other analysis methods to help verify the chemical and structural properties of the material. A series of gas sensing tests have been carried out, 2 mol% Sb ion-doped sample showed an excellent sensing performance for 100 ppm ethanol detection, with a response of 41.3, response/recovery time of 17 s/36 s. At a high humidity atmosphere (RH = 90 %), the device exhibited higher response (60.83) and better selectivity to 100 ppm ethanol. In this study, the gas sensing and humidity sensing mechanisms of Sb ions acted on the surface of In2O3 microspheres have been discussed exhaustedly. It is a significant study of gas-sensitive materials for ethanol detection.

Експериментальне дослідження електропровідності шлаків, що застосовуються у процесах спеціальної електрометалургії (СЕМ)

The development of the metallurgical industry of Ukraine largely depends on the export of special high-quality steels, which are obtained by special electrometallurgy. The quality of the metal obtained by such methods (primarily by the ESR method) is determined by the properties of the flux based on CaF2, from which liquid slag is formed during melting. Slag serves as a source of heat, as well as an environment in which the inclusions contained in the metal and harmful impurities are removed by chemical reaction or dissolution. Affecting the slag can affect not only the chemical composition but also the structure of the ingot. In general, these slags must not only have a high refining capacity, but also meet a number of other requirements, which in practice often come into conflict. In each case it is necessary to choose such slag which will meet the most important requirements, first of all has optimum electric conductivity. In order to use slags of rational chemical composition, experimental studies of the electrical conductivity of some slags used in SEM processes were performed. The work used an experimental setting, using a sensor of the original design. The measuring ring, which is immersed in a crucible with liquid slag, is made of a nitridescent cylinder, into which a thermocouple and tungsten electrodes are inserted to measure electrical conductivity. The measurements were performed using alternating current with a frequency of 400 Hz. The obtained experimental results correspond well to the literature data on fluxes with a chemical composition close to the studied ones and to the calculation data according to the empirical formula recommended in the literature. The results of the performed researches allow to recommend for industrial use fluxes AN-14 and AN-15, which, in addition, contain a small amount of fusible harmful feldspar

Stepwise activation of the pro-apoptotic protein Bid at mitochondrial membranes.

Caspase-8-cleaved Bid (cBid) associates with mitochondria and promotes the activation of BAX, leading to mitochondria outer membrane permeabilization (MOMP) and apoptosis. However, current structural models of cBid are largely based on studies using membrane vesicles and detergent micelles. Here we employ spin-label ESR and site-directed PEGylation methods to identify conformations of cBid at real mitochondrial membranes, revealing stepwise mechanisms in the activation process. Upon the binding of cBid to mitochondria, its structure is reorganized to expose the BH3 domain while leaving the structural integrity only slightly altered. The mitochondria-bound cBid is in association with Mtch2 and it remains in the primed state until interacting with BAX. The interaction subsequently triggers the fragmentation of cBid, causes large conformational changes, and promotes BAX-mediated MOMP. Our results reveal structural differences of cBid between mitochondria and other lipid-like environments and, moreover, highlight the role of the membrane binding in modifying cBid structure and assisting the inactive-to-active transition in function.

Late Miocene Elevated Horizontal Caves on the Highest Planation and its Significance for Karst Landform Evolution in Southern China

In Southern China, the development of the planations and cave levels are closely related to the evolution of the drainage systems and regional tectonics. The downcutting of this topographic surface represents the beginning of the modern regional river system, but researches on its age and development process have been minimal. A series of karst planations and large horizontal caves at the upstream area of the Three Gorges gives the opportunity to clarify the changes and chronology to the drainage system and the formation of these planations. A comprehensive study including cave morphology, cave infills, sediment provenance, and chronology has been carried out on the top phreatic caves located at planation surface near 2100m asl.The cave morphology features large horizontal trunk passage with maze-like branch conduits and small lower horizontal cave passages connected by shafts, the changes of cave morphology being related to the changes in the location of surface rivers. The cave deposits include fluvial gravel, thick clay, and speleothems have been analyses and dated. The lithological analysis of the cemented gravel deposits indicates that they came from the strata in Late Triassic-Early Permian. The results of 5.7 Ma and 3.8 Ma in cemented gravels were obtained by using cosmogenic burial dating, which constrained the minimum age of the top cave level and the planation .The widespread thick clay deposited in caves represent the rapid denudation of the Silurian clastic strata based on its U-Pb clastic zircon age analysis, and the age of loose clay is 810-600 ka using ESR method. Thick clay sediments transportation and cave enlargement generally resulted from large river development in humid climate. Subsequently speleothems are widely deposited in caves during the period 600-90ka (analyses by U-Th dating). Strangely the fluvial sediment deposition suddenly terminates, indicating the onset of rapid fluvial downcutting.This paper suggest that the timing of this planation is before late Miocene and tectonics played a key role in overlapped clastic caprocks denudation on it, while climate acted as the main forcing for cave enlargement and sediment during stable crustal periods after late Miocene. The adjustment of cave sediments and morphology is the response to the evolution of the hydrosystem caused by the decline of the water table through the cut-through of the Three Gorges and catchment disintegration in middle Pleistocene.

ESR Dating of Optically Bleached Quartz Grains: Assessing the Impact of Different Experimental Setups on Dose Evaluations

In recent years, our investigation has been centred on improving the reliability and accuracy of the ESR method applied to quartz grains. As part of this ongoing investigation, we present an intra-laboratory study to evaluate the impact of different experimental setups on the ESR measurement precision and dose evaluation for ESR dating of optically bleached quartz grains. Repeated measurements of quartz samples have been performed at CENIEH, Spain, using two different Bruker spectrometers (EMXmicro and Elexsys E500) and resonators (standard rectangular ER4102ST and cylindrical Super High QE cavities). Their performance in terms of sensitivity, measurement repeatability and dose determination are presented in this study. This intra-laboratory work has allowed to evaluate the robustness of our protocol for ESR dating of quartz grains and to study the potential impact of different experimental setups on dose evaluation, which is essential for future standardization of the ESR dating method. Our results indicate that all the different experimental setups provide comparable precision of the ESR intensity measurements. Moreover, all the ESR dose estimates are within 1-sigma error, suggesting that it is possible to compare results obtained by different laboratories when similar analytical procedures are followed. Finally, the higher sensitivity achieved by the SHQE resonator appears to be of particular interest when dealing with samples showing low ESR signal intensities.

Investigating the impact of structure of ferrotita-nium bars obtained by the electroslag remelting method on their crushing capacity

The structure and grinding ability of ferrotitanium ingots of different production methods have been researched. It has been found that the partial decay of primary TiFe2 grains with the formation of TiFe. in the structure of ingots of ferrotitanium ESR at a concentration of Ti 38–4 % improves the ability to crushing. Problem. Electrodes of the basic (fluoride-calcium) type, in particular, the UONI 13/55 brand are used for production of welded products of responsible function. They provide the highest plastic properties of the weld metal at a low content of non-metallic inclusions and gases, which is achieved by deoxidation of metal Mn, Si and Ti, introduced into the coating of the electrodes in the form of ferroalloys. However, in the ferrotitanium FeTi35A of the aluminothermic production method used in the production of welding electrodes, the volumetric part of inclusions reaches 0.3%. In this case, most (up to 70%) are refractory due to aluminum oxides, which contaminate the weld metal. The use of ferrotitanium produced by the electroslag remelting method, with a much lower content of non-metallic inclusions and impurities of non-ferrous metals, allows to improve the quality of the weld metal by reducing the number of exogenous inclusions. However, ingots of ferrotitanium obtained by the method of ESR with a similar content of Ti = 28,5 %–30,0 %, had a fairly low crushing point with the formation of a heterogeneous fraction. Goal. The purpose is to research the structure of ingots of ferrotitanium alloys with different titanium content, and to establish the dependence of the ability to crush on the structure and composition of ingots. Methodology. Ingots of ferrotitanium were obtained by electroslag remelting of combined electrodes composed of strips of low-carbon steel St3 and titanium W1-0 in copper water-cooled crystallizer with a cross section of 80–90 mm. The structure and ability of crushing for ingots with titanium content of 15, 20, 25, 30, 40, 45, 50 and 60 % have been tested. The ingots have been examined in the cast state after cooling in the air. A mixture of hydrofluoric, nitric acid and water in the ratio (1: 1: 3) has been used to researching the microstructure that has been determined using a MIM 8-M metallographic microscope. Crushing ability has been determined by a non-standard method on copra with a vertically falling cylindrical striker. It was found that the ability to crushing was the highest for the production of welding electrodes, ferrotitanium electroslag remelting with a concentration of Ti 38–48 % should be used. Originality. It was discovered that provided a Ti content of 45 % partial decay of primary TiFe2 grains with TiFe formation is observed. Upon cooling, the alloy becomes more balanced. The presence of the TiFe decay phase in the middle of the TiFe2 grain due to the difference in structure creates additional internal stresses and facilitates the destruction of the alloy. Practical value. The grinding coefficient of ferrotitanium ESR with a titanium content of 38–48 % and aluminum-thermal production are almost the same, which facilitates their use in the manufacture of welding electrodes.

The analysis of new higher operative bioactive compounds and chemical functional group from herbal plants through UF-HPLC-DAD and Fourier transform infrared spectroscopy methods and their biological activity with antioxidant potential process as future green chemical assay

The two herbal plants of Adhatoda vasica and Calotropis procera, commonly available in worldwide, were selected to explore their medicinal significance. The isolation and quantitative analysis of ten important bioactive compounds such as P-hydroxy-benzoic, Stictic acid, Usnic acid, Epigallocatechin gallate, Quercetin, Epigallocatechin, Catechin, Morin, Epicatechin and Naringenin, isolated from various parts was performed by using UF-HPLC-DAD and FTIR techniques. The antioxidant potentials of isolated bioactive compounds were evaluated through six methods including Electron spin resonance spectrometry, ABTS Assay, Diphenyl picrylhydrazyl (DPPH) radical scavenging assay, total radical-trapping, ORAC, and phycoerythrin assay on various plant parts. The advanced ESR method along with five other methods was applied for the first time on these species to evaluate the antioxidant potential of both species. The results showed that the flowers of Adhatoda vasica prove to be a rich source of important compounds in which Naringenin (15 ± 0.41) was higher in the flowers. The similar trend observed in twigs and seeds of Adhatoda vasica, the Epicatechin was higher in seeds of Calotropis procera. Results showed that the electron spin resonance spectrometry and ABTS radical scavenging assay methods showed higher antioxidant potential in Adhatoda vasica and Calotropis procera as compared to Diphenyl picrylhydrazyl (DPPH) radical scavenging assay.

Highly Efficient Photocatalytic Disinfection of Escherichia coli by Rose Bengal-Functionalized Graphene Oxide Nanosheets.

Rose Bengal (RB) was used as a functional pigment and poly dimethyl diallyl ammonium chloride was used as a coupling agent to modify Graphene Oxide (GO) in order to enhance the light absorption and ROS generation of GO. GO, RB and the obtained RB-PDDA-GO were characterized by scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectrometry, thermogravimetric analysis, Raman spectroscopy, UV-visible spectrophotometry, and X-ray photoelectron spectroscopy. The oxidation of hydroquinone to p-benzoquinone was used to evaluate the oxidation ability. Three kinds of reactive oxygen species (O₂·-, 1O₂ and ·OH) produced by the materials under light irradiation were detected by the ESR method using TEMP (2,2,6,6-tetramethyl-4-piperidine) and DMPO (5,5-dimethyl-1-pyrroline-N-oxide) as capture agents. The results showed that RB-PDDA-GO produced more ROS under light than GO. Antibacterial experiments were carried out with E. coli as the target strain to detect the actual utility of ROS produced by the materials. The results showed that RB-PDDA-GO had a significant sterilization effect.

Paramagnetic Resonance of Cr4+ and Mn2+ Ions in a Li2CaSiO4 Crystal

In a Li2CaSiO4 crystal, tetragonal Cr4+ centers (electron configuration 3d2, spin S = 1) are identified and investigated by the ESR method at different frequencies. The magnitude of zero-field splitting is determined. An additional signal with a reverse phase is observed in the region, in which the positions of the two transitions of Cr4+ coincide. For an uncontrolled impurity of Mn2+ ions (S = I = 5/2), the parameters and localization of the spin Hamiltonian are determined.

Novel Cu(II) and Ni(II) complexes of nicotinamide based Mannich base: Synthesis, characterization, DFT calculation, DNA binding, molecular docking, antioxidant, antimicrobial activities

Nicotinamide incorporating Mannich base ligand (L), Cu(II) and Ni (II) complexes of [CuLCl2].2H2O (1) and [NiLCl2].2H2O (2) were synthesized and characterized by elemental analysis, FT-IR, UV–Visible, ESR and mass spectrometric methods. The square planar geometry of the complexes (1 and 2) were confirmed from analytical and diverse spectroscopic methods. Cyclic votammetric behaviors of complexes (1 and 2) were studied. The optimized geometry of L, complexes (1 and 2) were obtained by Density Functional Theory (DFT) calculations. DNA binding ability of complexes (1 and 2) were studied by electronic absorption and fluorescence techniques. Both the spectroscopic results show that complex 1 (9.64 × 104 M−1) has good binding affinity than complex 2 (6.07 × 104 M−1). The interaction of complexes (1 and 2) with CT-DNA was explored by Molecular docking analysis revealed that an efficient interaction of complexes (1 and 2) with the DNA. The results indicate that prepared complexes (1 and 2) have better binding ability with DNA double helix. Antioxidant activities of complexes (1 and 2) have studied by DPPH method and results suggest that prepared complexes (1 and 2) have better radical scavenging ability. Antimicrobial activities of ligand (L) and complexes (1 and 2) were tested against selected bacterial and fungal pathogens results shows that prepared compounds have higher antimicrobial activity against E. coli and A. niger antimicrobial species than others.

. Навуглецьовування металу при різних способах ЕШП некомпактованої сталевої стружки

. Навуглецьовування металу при різних способах ЕШП некомпактованої сталевої стружки

Water soluble Cu(II) and Zn(II) complexes of bidentate-morpholine based ligand: synthesis, spectral, DFT calculation, biological activities and molecular docking studies

Copper(II) and zinc(II) complexes of the type [ML(AcO)2.H2O] were synthesized from bidentate-morpholine based Schiff base ligand (L - morpholinopropylimino)methyl)-6-methoxyphenol). The prepared ligand, copper(II) and zinc(II) complexes were characterized by elemental analysis, ESI-MS, 1H-NMR, FT-IR, UV-Visible, ESR and spectrometric methods. The elemental and ESI-MS results have been established that the prepared ligand and complexes possess 1:1 stoichiometric ratio. 1H-NMR and FT-IR results have been suggested that azomethine nitrogen and morpholine ring nitrogen atoms are coordinated with Cu(II) and Zn(II) metal ions. UV-Visible, ESI-MS and ESR spectroscopic results have been supported that the proposed structure of Cu(II) and Zn(II) complexes possess square pyramidal geometry. In order to confirm the proposed square pyramidal geometry of prepared complexes by DFT calculation has been studied. DNA binding ability of Cu(II) and Zn(II) complexes have been studied by electronic absorption and viscometric methods. These results reveal that Cu(II) and Zn(II) complexes interact with CT-DNA by the way of groove binding mode. Molecular docking studies result shows that synthesized compounds has better binding ability. The in vitro antioxidant activities of ligand, Cu(II) and Zn(II) complexes have been investigated by using the DPPH assay. The result shows that synthesized compounds have good radical scavenging activity against DPPH radical. Antimicrobial activities of synthesized ligand and its complexes have been tested against selected bacterial (gram positive & gram negative) and fungal species. The results reveal that Cu(II) and Zn(II) have good antimicrobial activity than ligand. Communicated by Ramaswamy H. Sarma

Development of Flow-Injection Spin-Trapping ESR Methods for Kinetic Study of the O2−• Radical Scavenging Reaction with Mixtures of Phenolic Antioxidants

AbstractThe apparent second-order rate constants (aks) of the reaction between the O2−• radical and mixed solutions (aAox) of caffeic acid (CA) and 4-hydroxy-coumaric acid (4CA) were estimated in this study; this was achieved by a flow-injection spin-trapping ESR (FI-ESR) method that employed 5,5-dimethyl-pyrroline-N-oxide (DMPO) as the spin-trapping reagent. The aAox solutions were prepared by varying the mixing molar ratio of CA (a = [CA]/([CA] + [4CA])). The FI-ESR signal intensities of the DMPO spin-adduct of the O2−• radical (DMPO/O2) were monitored in the absence (I0) and presence (I) of aAox to estimate the inhibition ratio Y (%) (Y = 100 × I/I0), and 50% inhibitory dose of aAox (aID50). Further, the aks values of aAox were evaluated using these aID50 values through a competitive reaction kinetics treatment, which was conducted by using the second-order rate constant of the spin-trapping reaction (k1). The value obtained for the aks of aAox showed excellent agreement with the calculated values (akscal) that were estimated from the molar ratio (a) weighted mean of the ks values of CA (CAks) and 4CA (4CAks): akscal = aCAks + (1 − a)4CAks. These results demonstrate that CA and 4CA contribute independently to the O2−• radical scavenging reactions, and that the aks values of aAox completely satisfy the additive property depending on the mixing molar ratio (a). The O2−• radical scavenging capacities of aAox were also evaluated as equivalent concentrations of CA (Y[CA]eq.) using the observed inhibition ratio Y (%), and the 50% inhibitory dose of CA (CAID50): Y[CA]eq. = CAID50 × (100 − Y)/Y. The estimated Y[CA]eq. values of aAox agreed with the calculated equivalent concentrations of CA (k[CA]eq.) that were obtained on the basis of the additive property established for aAox and aks: k[CA]eq. = [CA] + (4CAks/CAks) × [4CA].