The effect of ultrasound treatment on molecular mobility and organization of the main components in raw goat milk was studied by EPR and NMR spectroscopies. NMR relaxation studies showed an increase in the spin-lattice T1 and spin-spin T2 relaxation times in goat milk products (cream, anhydrous fat) and change in the diffusion of proton-containing molecules during ultrasound treatment. The diffusion became more uniform and could be rather accurately approximated by one effective diffusion coefficient Deff, which indicates homogenization of goat milk components, dispersion of globular and supermicellar formations under sonication. EPR studies have shown that molecular mobility and organization of hydrophobic regions in goat milk are similar to those observed in micellar formations of surfactants with a hydrocarbon chain length C12-C16. Ultrasound treatment did not affect submicellar and protein globule organization. Free radicals arising under ultrasound impact of milk reacted quickly with components of goat milk (triglycerides, proteins, fatty acids) and were not observed by spin trapping method.
Matched MeSH terms: Electron Spin Resonance Spectroscopy/methods
The interaction of simple and ternary Cu(II) complexes of 1,10-phenanthrolines with DNA has been studied extensively because of their various interesting and important functions such as DNA cleavage activity, cytotoxicity towards cancer cells, and DNA based asymmetric catalysis. Such functions are closely related to the DNA binding modes of the complexes such as intercalation, groove binding, and electrostatic surface binding. A variety of spectroscopic methods have been used to study the DNA binding mode of the Cu(II) complexes. Of all these methods, DNA-fiber electron paramagnetic resonance (EPR) spectroscopy affords unique information on the DNA binding structures of the complexes. In this review we summarize the results of our DNA-fiber EPR studies on the DNA binding structure of the complexes and discuss them together with the data accumulated by using other measurements.
Matched MeSH terms: Electron Spin Resonance Spectroscopy
Background radiation dose is used in dosimetry for estimating occupational doses of radiation workers or determining radiation dose of an individual following accidental exposure. In the present study, the absorbed dose and the background radiation level are determined using the electron spin resonance (ESR) method on tooth samples. The effect of using different tooth surfaces and teeth exposed with single medical X-rays on the absorbed dose are also evaluated. A total of 48 molars of position 6-8 were collected from 13 district hospitals in Peninsular Malaysia. Thirty-six teeth had not been exposed to any excessive radiation, and 12 teeth had been directly exposed to a single X-ray dose during medical treatment prior to extraction. There was no significant effect of tooth surfaces and exposure with single X-rays on the measured absorbed dose of an individual. The mean measured absorbed dose of the population is 34 ± 6.2 mGy, with an average tooth enamel age of 39 years. From the slope of a regression line, the estimated annual background dose for Peninsular Malaysia is 0.6 ± 0.3 mGy y(-1). This value is slightly lower than the yearly background dose for Malaysia, and the radiation background dose is established by ESR tooth measurements on samples from India and Russia.
Matched MeSH terms: Electron Spin Resonance Spectroscopy/methods*
Although mosquitos of the Anopheles umbrosus group have long been recognized as important vectors of human malaria in Malaya, there have been doubts about the origin of some of the malaria infections found, especially in A. umbrosus and A. letifer. Investigations have accordingly been carried out in the Malayan swamp-forest, in conjunction with laboratory studies, into the nature of malaria infections in wild-caught mosquitos, the biting behaviour of anophelines and the presence of malaria infection in man and animals. The authors conclude from the results reported in this paper that A. umbrosus is a vector of mouse deer malaria and rarely, if ever, transmits primate malaria; that A. letifer transmits both human and mouse deer malaria; and that A. baezai and A. roperi are probably vectors of mouse deer malaria.
Matched MeSH terms: Electron Spin Resonance Spectroscopy*
SnO₂ nanoparticle production using thermal treatment with tin(II) chloride dihydrate and polyvinylpyrrolidone capping agent precursor materials for calcination was investigated. Samples were analyzed using X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), energy dispersive X-ray (EDX), transmission electron microscopy (TEM), Fourier Transform Infrared Spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), diffuse UV-vis reflectance spectra, photoluminescence (PL) spectra and the electron spin resonance (ESR). XRD analysis found tetragonal crystalline structures in the SnO₂ nanoparticles generated through calcination. EDX and FT-IR spectroscopy phase analysis verified the derivation of the Sn and O in the SnO₂ nanoparticle samples from the precursor materials. An average nanoparticle size of 4–15.5 nm was achieved by increasing calcination temperature from 500 °C to 800 °C, as confirmed through TEM. The valence state and surface composition of the resulting nanoparticle were analyzed using XPS. Diffuse UV-vis reflectance spectra were used to evaluate the optical energy gap using the Kubelka-Munk equation. Greater calcination temperature resulted in the energy band gap falling from 3.90 eV to 3.64 eV. PL spectra indicated a positive relationship between particle size and photoluminescence. Magnetic features were investigated through ESR, which revealed the presence of unpaired electrons. The magnetic field resonance decreases along with an increase of the g-factor value as the calcination temperature increased from 500 °C to 800 °C. Finally, Escherichia coli ATCC 25922 Gram (–ve) and Bacillus subtilis UPMC 1175 Gram (+ve) were used for in vitro evaluation of the tin oxide nanoparticle’s antibacterial activity. This work indicated that the zone of inhibition of 22 mm has good antibacterial activity toward the Gram-positive B. subtilis UPMC 1175.
Matched MeSH terms: Electron Spin Resonance Spectroscopy
The synthesis and characterization of an oxidovanadium(iv) [VIVO(L)(acac)] (1) and of two dioxidovanadium(v) [VVO2(L')] (2) and [VVO2(L)] (2a) complexes of the Schiff base formed from the reaction of 4-(p-fluorophenyl) thiosemicarbazone with pyridine-2-aldehyde (HL) are described. The oxidovanadium(iv) species [VIVO(L)(acac)] (1) was synthesized by the reaction of VIVO(acac)2 with the thiosemicarbazone HL in refluxing ethanol. The recrystallization of [VIVO(L)(acac)] (1) in DMF, CH3CN or EtOH gave the same product i.e. the dioxidovanadium(v) complex [VVO2(L)] (2a); however, upon recrystallization of 1 in DMSO a distinct compound [VVO2(L')] (2) was formed, wherein the original ligand L- is transformed to a rearranged one, L'-. In the presence of DMSO the ligand in complex 1 is found to undergo methylation at the carbon centre attached to imine nitrogen (aldimine) and transformed to the corresponding VVO2-species through in situ reaction. The synthesized HL and the metal complexes were characterized by elemental analysis, IR, UV-Vis, NMR and EPR spectroscopy. The molecular structure of [VVO2(L')] (2) was determined by single crystal X-ray crystallography. The methylation of various other ligands and complexes prepared from different vanadium precursors under similar reaction conditions was also attempted and it was confirmed that the imine methylation observed is both ligand and metal precursor specific. Complexes 1 and 2 show in vitro insulin-like activity against insulin responsive L6 myoblast cells, higher than VIVO(acac)2, with complex 1 being more potent. In addition, the in vitro cytotoxicity studies of HL, and of complexes 1 and 2 against the MCF-7 and Vero cell lines were also done. The ligand is not cytotoxic and complex 2 is significantly more cytotoxic than 1. DAPI staining experiments indicate that an increase in the time of incubation and an increase of concentration of the complexes lead to the increase in cell death.
Matched MeSH terms: Electron Spin Resonance Spectroscopy
In this investigation, a new design based on a PANDA ring resonator as an optical trapping tool for tangle protein, molecular motor storage, and delivery is proposed. The optical vortices are generated and the trapping mechanism is controlled in the same way as the conventional optical tweezers. The trapping force is produced by a combination of the gradient field and scattering photons. The required molecular volume is trapped and moved dynamically within the molecular network. The tangle protein and molecular motor can be transported and delivered to the required destinations for Alzheimer's diagnosis by molecular buffer and bus network.
Matched MeSH terms: Electron Spin Resonance Spectroscopy
Phytochemical and bioactivity studies of the leaves and stem barks of Tibouchina semidecandra L. have been carried out. The ethyl acetate extract of the leaves yielded four flavonoid compounds, identified as quercetin, quercetin 3-O-α-l-(2''-O-acetyl) arabinofuranoside, avicularin, and quercitrin, while the stem barks gave one ellagitannin, identified as 3,3'-O-dimethyl ellagic acid 4-O-α-l-rhamnopyranoside. Evaluation of the antioxidative activity on the crude extracts and pure compounds by electron spin resonance (ESR) and ultraviolet-visible (UV-vis) spectrophotometric assays showed that the pure isolated polyphenols and the EtOAc extract possessed strong antioxidative capabilities. Quercetin was found to be the most active radical scavenger in DPPH-UV and ESR methods with SC(50) values of 0.7 μM ± 1.4 and 0.7 μM ± 0.6 μM, respectively, in the antioxidant assay. A combination of quercetin and quercitrin was tested for synergistic antioxidative capacity;, however, there was no significant improvement observed. Quercetin also exhibited strong antityrosinase activity with a percent inhibition of 95.0% equivalent to the positive control, kojic acid, in the tyrosinase inhibition assay.
Matched MeSH terms: Electron Spin Resonance Spectroscopy
A new prenylated dihydrochalcone, 2',4'-dihydroxy-4-methoxy-3'-prenyldihydrochalcone (1), along with two known compounds, 2',4',4-trihydroxy-3'-prenylchalcone (2) and 2',4-dihydroxy-3',4'-(2,2-dimethylchromene)chalcone (3) were isolated from the leaves of Artocarpus lowii. The structures of 1-3 were elucidated by spectroscopic methods and by comparison with data reported in the literature. Compounds 1-3 showed strong free radical scavenging activity towards 2,2-diphenyl-1-picrylhydrazyl (DPPH) measured by electron spin resonance (ESR) spectrometry.
Matched MeSH terms: Electron Spin Resonance Spectroscopy
A series of ternary metal(ii) complexes {M(phen)(edda); 1a (Cu), 1b (Co), 1c (Zn), 1d (Ni); H(2)edda = N,N(')-ethylenediaminediacetic acid} of N,N'-ethylene-bridged diglycine and 1,10-phenanthroline were synthesized and characterized by elemental analysis, FTIR, UV-visible spectroscopy and magnetic susceptibility measurement. The interaction of these complexes with DNA was investigated using CD and EPR spectroscopy. MTT assay results of 1a-1c , screened on MCF-7 cancer cell lines, show that synergy between the metal and ligands results in significant enhancement of their antiproliferative properties. Preliminary results from apoptosis and cell cycle analyses with flow cytometry are reported. seems to be able to induce cell cycle arrest at G(0)/G(1). The crystal structure of 1a is also included.
Matched MeSH terms: Electron Spin Resonance Spectroscopy
Thymoquinone (TQ), a bioactive constituent of Nigella sativa Linn (N. sativa) has demonstrated several neuropharmacological attributes. In the present study, the neuroprotective properties of TQ were investigated by studying its anti-apoptotic potential to diminish β-amyloid peptide 1-40 sequence (Aβ1-40)-induced neuronal cell death in primary cultured cerebellar granule neurons (CGNs). The effects of TQ against Aβ1-40-induced neurotoxicity, morphological damages, DNA condensation, the generation of reactive oxygen species, and caspase-3, -8, and -9 activation were investigated. Pretreatment of CGNs with TQ (0.1 and 1 μM) and subsequent exposure to 10 μM Aβ1-40 protected the CGNs against the neurotoxic effects of the latter. In addition, the CGNs were better preserved with intact cell bodies, extensive neurite networks, a loss of condensed chromatin and less free radical generation than those exposed to Aβ1-40 alone. TQ pretreatment inhibited Aβ1-40-induced apoptosis of CGNs via both extrinsic and intrinsic caspase pathways. Thus, the findings of this study suggest that TQ may prevent neurotoxicity and Aβ1-40-induced apoptosis. TQ is, therefore, worth studying further for its potential to reduce the risks of developing Alzheimer's disease.
Matched MeSH terms: Electron Spin Resonance Spectroscopy
A series of ternary copper(II)-1,10-phenanthroline complexes with glycine and methylated glycine derivatives, [Cu(phen)(aa)(H(2)O)]NO(3)·xH(2)O 1-4 (amino acid (aa): glycine (gly), 1; DL: -alanine (DL: -ala), 2; 2,2-dimethylglycine (C-dmg), 3; sarcosine (sar), 4), were synthesized and characterized by FTIR, elemental analysis, electrospray ionization-mass spectra (ESI-MS), UV-visible spectroscopy and molar conductivity measurement. The determined X-ray crystallographic structures of 2 and 3 show each to consist of distorted square pyramidal [Cu(phen)(aa)(H(2)O)](+) cation, a nitrate counter anion, and with or without lattice water, similar to previously reported structure of [Cu(phen)(gly)(H(2)O)]NO(3)·1½H(2)O. It is found that 1-4 exist as 1:1 electrolytes in aqueous solution, and the cationic copper(II) complexes are at least stable up to 24 h. Positive-ion ESI-MS spectra show existence of only undissociated [Cu(phen)(aa)](+) species. Electron paramagnetic resonance, gel electrophoresis, fluorescence quenching, and restriction enzyme inhibition assay were used to study the binding interaction, binding affinity and selectivity of these complexes for various types of B-form DNA duplexes and G-quadruplex. All complexes can bind selectively to DNA by intercalation and electrostatic forces, and inhibit topoisomerase I. The effect of the methyl substituents of the coordinated amino acid in the above complexes on these biological properties are presented and discussed. The IC(50) values (24 h) of 1-4 for nasopharyngeal cancer cell line HK1 are in the range 2.2-5.2 μM while the corresponding values for normal cell line NP69 are greater than 13.0 μM. All complexes, at 5 μM, induced 41-60 % apoptotic cell death in HK1 cells but no significant cell death in NP69 cells.
Matched MeSH terms: Electron Spin Resonance Spectroscopy