共查询到20条相似文献,搜索用时 15 毫秒
1.
A multiphase model of metal ion speciation in human interstitial fluid was constructed and the effect of Pr(III) on Ca(II)
speciation was studied. Results show that free Ca2+, [Ca(HCO3)], and [Ca(Lac)] are the main species of Ca(II). Because of the competition of Pr(III) for ligands with Ca(II), the percentages
of free Ca2+, [Ca(Lac)], and [Ca(His)(Thr)H3] increase gradually and the percentages of CaHPO4(aq) and [Ca(Cit)(His)H2] decrease gradually with the increase in the total concentration of Pr(III). However, the percentages of [Ca(HCO3)] and CaCO3(aq) first increase and then begin to decrease when the total concentration of Pr(III) exceeds 6.070×10−4
M. 相似文献
2.
A mutiphase model of metal ion speciation in human interstitial fluid was constructed and the effect of Pr(III) on Ca(II)
speciation was studied. Results show that Ca(II) mainly distributes in free Ca2+, [Ca(HCO3)], and [Ca(Lac)]. Because of the competition of Pr(III) for ligands with Ca(II), with the total concentration of Pr(III)
rising, the percentages of free Ca2+, [Ca(Lac)] and [Ca(His)(Thr)H3], gradually increase and the percentages of CaHPO4(aq) and [Ca(Cit)(His)H2] gradually decrease. However, the percentages of [Ca(HCO3)] and CaCO3(aq) first increase, and then begin to decrease when the total concentration of Pr(III) exceeds 6.070×10−4
M. 相似文献
3.
The speciation and distribution of Zn(II) and the effect of Gd(III) on Zn(II) speciation in human blood plasma were studied
by computer simulation. The results show that, in normal blood plasma, the most predominant species of Zn(II) are [Zn(HSA)]
(58.2%), [Zn(IgG)](20.1%), [Zn(Tf)] (10.4%), ternary complexes of [Zn(Cit)(Cys)] (6.6%) and of [Zn(Cys)(His)H] (1.6%), and
the binary complex of [Zn(Cys)2H] (1.2%). When zinc is deficient, the distribution of Zn(II) species is similar to that in normal blood plasma. Then, the
distribution changes with increasing zinc(II) total concentration. Overloading Zn(II) is initially mainly bound to human serum
albumin (HSA). As the available amount of HSA is exceeded, phosphate metal and carbonate metal species are established. Gd(III)
entering human blood plasma predominantly competes for phosphate and carbonate to form precipitate species. However, Zn(II)
complexes with phosphate and carbonate are negligible in normal blood plasma, so Gd(III) only have a little effect on zinc(II)
species in human blood plasma at a concentration above 1.0×10−4
M. 相似文献
4.
A multiphase model of metal ion species in human interstitial fluid was constructed under physiological conditions. The effect
of Pr(III) on Zn(II) species was studied. At the normal conditions, Zn(II) species mainly distribute in [Zn(HSA)], [Zn(IgG)],
and [Zn(Cys)2H]+. With the Pr(III) level increased, the apparent competition of Pr(III) for ligands lead to the redistribution of Zn(II) species. 相似文献
5.
《Chemical Speciation and Bioavailability》2013,25(2):31-39
AbstractChromium speciation in the presence of organic chromium(III) complexes was investigated using solid-phase extraction. The adsorptions of Cr(VI) and Cr(III) on alumina and pumice powder were studied. Maximum sorption of Cr(VI) was obtained by alumina (90.22%), while Cr(III) was highly adsorbed onto pumice powder (86.65%). This result shows that pumice may be a new and promising adsorbent for Cr(III). The experimental equilibrium data for Cr(VI) adsorption onto alumina and Cr(III) sorption onto pumice were analysed using Langmuir and Freundlich isotherms. The separation and adsorption of Cr(VI), Cr(III) and five organic chromium(III) complexes onto pumice and alumina at different pH values were evaluated. Ethylenediaminetetraacetate (EDTA), oxalate, citrate, glycine, alanine and 8-hydroxyqinoline were used as ligands. Sorption of alanine and ethylenediaminetetraacetate complexes was higher onto alumina than pumice at pH>3. The enhancement of adsorption of chromium(III) complexes onto pumice was achieved by surface modification of pumice using a surfactant, namely hexadecyltrimethylammoniumbromür (HDTMA). The presence of surfactant enhanced the adsorption of Cr(III) citrate, oxalate, glycine and 8-hydroxyquinoline complexes onto pumice. However, the adsorption of EDTA and alanine complexes decreased, with ratio of 13.40% and 4.00% respectively. Here we demonstrate that chromium speciation methods depending on adsorption onto various adsorbents including alumina may lead erroneous results. Analytical measurements were performed by flame AAS, data were obtained by standard addition method. 相似文献
6.
The complex formation of europium(III) and curium(III) with urea in aqueous solution has been studied at I = 0.1 M (NaClO4), room temperature and trace metal concentrations in the pH-range of 1-8 at various ligand concentrations using time-resolved laser-fluorescence spectroscopy. While for curium(III) the luminescence maximum is red shifted upon complexation, in case of europium(III) emission wavelengths remain unaltered but a significant change in peak splitting occurs. Both heavy metals form weak complexes of the formulae ML3+ and MLOH2+ with urea. Stability constants were determined to be log β110 = −0.12 ± 0.05 and log β11-1 = −6.86 ± 0.15 for europium(III) and log β110 = −0.28 ± 0.12 and log β11-1 = −7.01 ± 0.15 for curium(III). 相似文献
7.
《Chemical Speciation and Bioavailability》2013,25(4):241-246
AbstractChemical speciation of binary complexes of indium(III) with oxalic acid has been investigated pH metrically at 303 K and at an ionic strength of 0.2 mol dm?3. The approximate formation constants have been calculated with the computer program SCPHD utilizing the experimental data obtained by monitoring H+ ion concentration. The formation constants thus obtained are refined with the computer program, MINIQUAD75 using primary alkalimetric data. The selection of the best-fit chemical model is based on the statistical parameters and residual analysis. The major complexes formed are In(C2O4)2?, In(C2O4)33?, [In(C2O4)2OH]2? and [In(C2O4)2 (OH)2]3?. The distribution patterns of the different species with the pH values showed that In(C2O4)2? is the predominant species. 相似文献
8.
Tina Osswald 《Inorganica chimica acta》2010,363(3):474-480
The synthesis, characterization, and application in asymmetric catalytic cyclopropanation of Rh(III) and Ir(III) complexes containing (Sa,RC,RC)-O,O′-[1,1′-binaphthyl-2,2′-diyl]-N,N′-bis[1-phenyl-ethyl]phosphoramidite (1) are reported. The X-ray structures of the half-sandwich complexes [MCl2(C5Me5)(1,κP)] (M = Rh, 2a; M = Ir, 2b) show that the metal-phosphoramidite bond is significantly shorter in the Ir(III) analog. Chloride abstraction from 2a (with CF3SO3SiMe3 or with CF3SO3Me) and from 2b (with AgSbF6) gives the cationic species [MCl(C5Me5)(1,2-η-1,κP)]+ (M = Rh, 3a; M = Ir, 3b), which display a secondary interaction between the metal and a dangling phenethyl group (NCH(CH3)Ph) of the phosphoramidite ligand, as indicated by NMR spectroscopic studies. Complexes 3a and 3b slowly decompose in solution. In the case of 3b, the binuclear species [Ir2Cl3(C5Me5)2]+ is slowly formed, as indicated by an X-ray study. Preliminary catalytic tests showed that 3a cyclopropanates styrene with moderate yield (35%) and diastereoselectivity (70:30 trans:cis ratio) and with 32% ee (for the trans isomer). 相似文献
9.
The stability constants of Am+3, Cm3+ and Eu3+ with ortho silicate, were measured at pH 3.50 and in ionic strengths of 0.20-1.00 M (NaClO4) by the solvent extraction method. The Am+3, Cm3+ and Eu3+ forms 1:1 complex with ortho silicate ion at pH 3.60 with the stability constant (log β1) value of 8.02 ± 0.10, 7.78 ± 0.08 and 7.81 ± 0.11, respectively. The stability of these metal ions decrease with increased ionic strength from 0.20 to 1.00 M (NaClO4) for silicic acid concentrations of 0.002-0.020 M. Increasing silicic acid concentration above 0.02 M increased the amount of M3+ extracted into the organic phase, contrary to the trend usually observed for increased ligand concentration in solvent extraction. This reversed trend is likely due to the extraction of cationic species of silicic acid by HDEHP. Aging time (60-300 min) had no effect on the stability constant of these metal ions for 0.002-0.020 M silicic acid at pH 3.50 and I = 0.20 M (NaClO4).The fraction of polymeric silicic acid present in solutions of 0.20-4.50 M NaClO4 solutions at pH 3.0-10.0, T = 0-60 °C and aging time = 5-300 min was measured for determination of the silicomolybdate reaction to ascertain the proper conditions to study metal-silicate complexation. 相似文献
10.
Using the 1:2 condensate of benzildihydrazone and 2-acetylpyridine as a tetradentate N donor ligand L, LaL(NO3)3 (1) and EuL(NO3)3 (2), which are pale yellow in colour, are synthesized. While single crystals of 1 could not be obtained, 2 crystallises as a monodichloromethane solvate, 2·CH2Cl2 in the space group Cc with a = 11.7099(5) Å, b = 16.4872(5) Å, c = 17.9224(6) Å and β = 104.048(4)°. From the X-ray crystal structure, 2 is found to be a rare example of monohelical complex of Eu(III). Complex 1 is diamagnetic. The magnetic moment of 2 at room temperature is 3.32 BM. Comparing the FT-IR spectra of 1 and 2, it is concluded that 1 also is a mononuclear single helix. 1H NMR reveals that both 1 and 2 are mixtures of two diastereomers. In the case of the La(III) complex (1), the diastereomeric excess is only 10% but in the Eu(III) complex 2 it is 80%. The occurrence of diastereomerism is explained by the chiralities of the helical motif and the type of pentakis chelates present in 1 and 2. 相似文献
11.
Arsenic speciation data are presented for pore waters squeezed from some native and anthropogenically influenced sediments.Ten stations were sampled with a box corer (to 20 cm) at two British Columbia coastal sites that are influenced by mine-tailings discharges. These are Rupert Inlet and Alice Arm as well as their associated systems of Quatsino Sound/Holberg Inlet and Hastings Arm respectively.Total dissolved arsenic concentrations (As
D) usually exhibited subsurface maxima at 5–10 cm and were generally related to solid phase arsenic (As
p) levels, but there was also a dependence on the nature of the substrate. Tailings exhibited both the lowest (Rupert Inlet) and the highest (Alice Arm) As
D values. Inorganic arsenicals, arsenate (AsV) and arsenite (AsIII) constituted the majority (>90%) of the dissolved species butevery sample contained organoarsenicals. This is the first report of mono-, di- and tri-methylated arsenic species in marine interstitial water.A strong positive correlation between the sum of the methylarsenic compounds (MeAs) and the total dissolved arsenic (As
D) was found, indicating in situ microbial methylation similar to that observed in non-aquatic systems. Flux values for arsenic at the sediment-water interface suggest that, at present, there is no significant mobilization of arsenic from these mine-derived sediments into the water column. 相似文献
12.
Mari Matsumura 《Inorganica chimica acta》2008,361(8):2553-2556
Under 254 nm irradiation in chloroform, [Re2Cl8]2− is converted cleanly to [Re2Cl9]−. The reaction is initiated primarily through light absorbed by the chloroform. The experimental rate expression is , where I0 is the incident light intensity and fS is the fraction of light absorbed by the solvent. The rate law is consistent with mechanisms involving either [Re2Cl8]− or [Re2Cl9]2− as an intermediate. 相似文献
13.
The preparation and variable temperature-magnetic investigation of three squarate-containing complexes of formula [Fe2(OH)2(C4O4)2(H2O)4]·2H2O (1) [Cr2(OH)2(C4O4)2(H2O)4]·2H2O (2) and [Co(C4O4)(H2O)4]n (3) [H2C4O4 = 3.4-dihydroxycyclobutene-1,2-dione (squaric acid)] together with the crystal structures of 1 and 3 are reported. Complex 1 contains discrete centrosymmetric [Fe2(OH)2(C4O4)2(H2O)4] diiron(II) units where the iron pairs are joined by a di-μ-hydroxo bridge and two squarate ligands acting as bridging groups through adjacent oxygen atoms. Two coordinated water molecules in cis position complete the octahedral environment at each iron atom in 1. The iron-iron distance with the dinuclear unit is 3.0722(6) Å and the angle at the hydroxo bridge is 99.99(7)°, values which compare well with the corresponding ones in the isostructural compound 2 (2.998 Å and 99.47°) whose structure was reported previously. The crystal structure of 3 contains neutral chains of squarato-O1,O3-bridged cobalt(II) ions where four coordinated water molecules complete the six-coordination at each cobalt atom. The cobalt-cobalt separation across the squarate bridge is 8.0595(4) Å. A relatively important intramolecular antiferromagnetic coupling occurs in 1 whereas it is very weak in 2, the exchange pathway being the same [J = −14.4 (1) and −0.07 cm−1 (2), the spin Hamiltonian being defined as ]. A weak intrachain antiferromagnetic interaction between the high-spin cobalt(II) ions occurs in 3 (J = −0.30 cm−1). The magnitude and nature of these magnetic interactions are discussed in the light of their respective structures and they are compared with those reported for related systems. 相似文献
14.
Gold(III) compounds have been recognized as anticancer agents due to their structural and electronic similarities with currently employed platinum(II) species. An added benefit to gold(III) agents is the ability to overcome cisplatin resistance. This work identified four gold(III) compounds, [Au(Phen)Cl2]PF6, [Au(DPQ)Cl2]PF6, [Au(DPPZ)Cl2]PF6, and [Au(DPQC)Cl2]PF6, (Phen = 1,10-phenanthroline, DPQ = dipyrido[3,2-d:2′,3′-f]quinoxaline, DPPZ = dipyrido[3,2-a:2′,3′-c] phenazine, DPQC = dipyrido[3,2-d:2′,3′-f] cyclohexyl quinoxaline) that exhibited anticancer activity in both cisplatin sensitive and cisplatin resistant ovarian cancer cells. Two of these compounds, [Au(DPQ)Cl2]PF6 (AQ) and [Au(DPPZ)Cl2]PF6 (AZ), displayed exceptional anticancer activity and were the focus of more intensive mechanistic study. At the molecular level, AQ and AZ formed DNA adducts, generated free radicals, and upregulated pro-apoptotic signaling molecules (p53, caspases, PARP, death effectors). Taken together, these two novel gold(III) polypyridyl complexes exhibit potent antitumor activity in cisplatin resistant cancer cells. These activities may be mediated, in part, by the activation of apoptotic signaling. 相似文献
15.
Vitalie Stavila Aurelian Gulea Sergiu Shova Peter Petrenko Fabrice Riblet 《Inorganica chimica acta》2004,357(7):2060-2068
Two novel cobalt(III)-bismuth(III) heterometallic compounds [Co(NxH)2(An)2]2[Bi(EDTA)(H2O)]2 · 7H2O (1) and [Co(NxH)2(p-Tol)2][Bi(EDTA)] · 4H2O (2) [An-aniline, p-Tol-para-toluidine, NxH-1,2-cyclohexanedionedioximate-ion, EDTA-ethylenediaminetetraacetate-ion] have been synthesized and characterized by NMR, thermogravimetry and single X-ray crystallography. Substitution of the aniline by para-toluidine molecules leads to radical changes in the anionic sub-lattice: from monomeric form to polymeric one. The coordination number of bismuth is 7+1 in 1, and 8 in 2; Bi coordination polyhedron in 1 can be described as a two-capped trigonal prism, while in 2 as a dodecahedron. The Co atoms in 1 and 2 have an octahedral coordination. NMR spectroscopy in DMSO solution confirms the trans-configuration of the complex cations in 1 and 2 by observation of a broad singlet of two symmetric hydrogen bonds. The NCH2CH2N component of EDTA ligand is in the domain of the fast exchange and the signal from this group is a singlet, while four acetate methylene protons give rise to an AB quartet system. It was shown that thermolysis of 1 and 2 occurs in three successive stages, via the dehydration, pyrolysis of the ligands and, finally, the formation of a sillenite-type phase Bi26−xCoxO40−δ and small quantities of Co3O4. 相似文献
16.
17.
Muhammad Naeem Khan Muhammad Rasul Jan Jasmin Shah Sang Hak Lee Young Ho Kim 《Luminescence》2013,28(6):915-921
A highly sensitive and simple method for identifying sulpiride in pharmaceutical formulations and biological fluids is presented. The method is based on increased chemiluminescence (CL) intensity of a luminol–H2O2 system in response to the addition of Cr (III) under alkaline conditions. The CL intensity of the luminol–H2O2–Cr (III) system was greatly enhanced by the addition of sulpiride and the CL intensity was proportional to the concentration of sulpiride in a sample solution. Various parameters affecting the CL intensity were systematically investigated and optimized for determination of the sulpiride in a sample. Under the optimum conditions, the CL intensity was proportional to the concentration of sulpiride in the range of 0.068–4.0 µg/mL, with a good correlation coefficient of 0.997. The limit of detection (LOD) and limit of quantification (LOQ) were found to be 8.50 × 10‐6 µg/mL and 2.83 × 10‐5 µg/mL, respectively. The method presented here produced good reproducibility with a relative standard deviation (RSD) of 2.70% (n = 7). The effects of common excipients and metal ions were studied for their interference effect. The method was validated statistically through recovery studies and successfully applied for the determination of sulpiride in pure form, pharmaceutical preparations and spiked human plasma samples. The percentage recoveries were found to range from 99.10 to 100.05% for pure form, 98.12 to 100.18% for pharmaceutical preparations and 97.9 to 101.4% for spiked human plasma. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
18.
Bone tissue engineering: the role of interstitial fluid flow 总被引:18,自引:0,他引:18
It is well established that vascularization is required for effective bone healing. This implies that blood flow and interstitial fluid (ISF) flow are required for healing and maintenance of bone. The fact that changes in bone blood flow and ISF flow are associated with changes in bone remodeling and formation support this theory. ISF flow in bone results from transcortical pressure gradients produced by vascular and hydrostatic pressure, and mechanical loading. Conditions observed to alter flow rates include increases in venous pressure in hypertension, fluid shifts occurring in bedrest and microgravity, increases in vascularization during the injury-healing response, and mechanical compression and bending of bone during exercise. These conditions also induce changes in bone remodeling. Previously, we hypothesized that interstitial fluid flow in bone, and in particular fluid shear stress, serves to mediate signal transduction in mechanical loading- and injury-induced remodeling. In addition, we proposed that a lack or decrease of ISF flow results in the bone loss observed in disuse and microgravity. The purpose of this article is to review ISF flow in bone and its role in osteogenesis. 相似文献
19.
Pavel Gromov Irina Gromova Charlotta J. Olsen Vera Timmermans-Wielenga Mai-Lis Talman Reza R. Serizawa José M.A. Moreira 《Biochimica et Biophysica Acta - Proteins and Proteomics》2013,1834(11):2259-2270
Tumor interstitial fluid (TIF) is a proximal fluid that, in addition to the set of blood soluble phase-borne proteins, holds a subset of aberrantly externalized components, mainly proteins, released by tumor cells and tumor microenvironment through various mechanisms, which include classical secretion, non-classical secretion, secretion via exosomes and membrane protein shedding. Consequently, the interstitial aqueous phase of solid tumors is a highly promising resource for the discovery of molecules associated with pathological changes in tissues. Firstly, it allows one to delve deeper into the regulatory mechanisms and functions of secretion-related processes in tumor development. Secondly, the anomalous secretion of molecules that is innate to tumors and the tumor microenvironment, being associated with cancer progression, offers a valuable source for biomarker discovery and possible targets for therapeutic intervention. Here we provide an overview of the features of tumor-associated interstitial fluids, based on recent and updated information obtained mainly from our studies of breast cancer. Data from the study of interstitial fluids recovered from several other types of cancer are also discussed. This article is a part of a Special Issue entitled: The Updated Secretome. 相似文献
20.
Nadia Aguerssif Mohamed Benamor Malek Kachbi Mohamed Tahar Draa 《Journal of trace elements in medicine and biology》2008,22(3):175-182
Derivative spectrophotometry (graphical method) and partial least-squares regression (numerical method) methods were developed for the spectrophotometric multi-component analysis of post-haemodialysis fluids and synthetic mixtures containing Al(III) and Fe(III) without any chemical separation. The complexes of these metal ions with chrome azurol S were formed immediately at pH 5.5 and were stable for at least 3h. The graphical method is based on the use of first-derivative spectra for evaluation because working wavelength determination was more precise and spectral overlap was less than in the ordinary spectra. Two wavelengths at which the complexes exhibited maximum absorption values for Fe(III) and Al(III) were selected as analytical wavelengths, i.e., 675 and 623.5nm, respectively. Lambert-Beer's law is obeyed between 0.0896-8.064mug/mL Fe(III) and 0.054-0.486mug/mL Al(III). Limits of detection for Fe(III) and Al(III) were 0.056 and 0.044mug/mL, respectively. The reproducibility, expressed as variation coefficients, for two sets of 10 standard mixtures containing 3.584mug/mL Fe(III) and 0.27mug/mL Al(III) were 1.9% and 2% for iron and aluminium, respectively. In the numerical method, a training set was randomly prepared by using 14 samples. The concentration of each component has been varied in the linear range of the analytical signal. The spectral regions between 510 and 720nm were selected for the analysis of the binary mixture of Fe(III)/Al(III). The proposed methods were validated by using synthetic binary mixtures and applied to the simultaneous determination of Fe(III) and Al(III) in post-haemodialysis samples. The obtained results were compared with each other; in general, both multi-component methods gave rise to similar recovery results for laboratory-prepared mixtures and real samples. 相似文献