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1.
J Clin Lab Anal ; 34(5): e23204, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32406547

RESUMO

BACKGROUND: Hip fracture in the elderly is a health burden worldwide due to its high mortality rate. This study was conducted to determine the possible mechanisms of osteopontin (OPN) and ß-carboxy-terminal cross-linking telopeptide of type I collagen (ß-CTX) in hip fracture in the elderly. MATERIALS AND METHODS: In the study, we recruited 108 elderly patients with hip fracture diagnosed from May 2012 to May 2015 at the Third Hospital of Xiamen and 86 healthy individuals without a history of hip fracture were taken as controls. Serum levels of OPN and ß-CTX were then determined. The T and Z values for bone mineral density (BMD) were also measured. Moreover, logistic regression analysis was performed to assess the risk and protective factors for hip fracture in the elderly. RESULTS: Serum levels of both OPN and ß-CTX were increased in elderly patients with hip fracture. OPN was positively correlated with ß-CTX. In addition, the levels of OPN and ß-CTX shared a positive association with the age, and a negative association with the BMD, in terms of T and Z values of the hip. In addition, increased BMD and outdoor sports might be protective factors for hip fracture, and an increase in levels of OPN and ß-CTX might be associated with a higher risk of hip fracture in the elderly population. DISCUSSION: Collectively, increased serum levels of OPN and ß-CTX might be correlated with a higher risk of a hip fracture and have predictive values in the occurrence of hip fracture in the elderly.


Assuntos
Densidade Óssea , Colágeno Tipo I/sangue , Fraturas do Quadril/sangue , Osteopontina/sangue , Peptídeos/sangue , Distribuição por Idade , Idoso , Idoso de 80 Anos ou mais , Animais , Biomarcadores/sangue , Índice de Massa Corporal , Estudos de Casos e Controles , Feminino , Idoso Fragilizado , Humanos , Masculino , Pessoa de Meia-Idade , Leite , Osteoporose/sangue
2.
Theor Appl Genet ; 130(11): 2395-2410, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28825113

RESUMO

KEY MESSAGE: Rsc15, a novel locus underlying soybean resistance to SMV, was fine mapped to a 95-kb region on chromosome 6. The Rsc15- mediated resistance is likely attributed to the gene GmPEX14 , the relative expression of which was highly correlated with the accumulation of H 2 O 2 along with the activities of POD and CAT during the early stages of SMV infection in RN-9. Soybean mosaic virus (SMV) causes severe yield losses and seed quality deterioration in soybean [Glycine max (L.) Merr.] worldwide. A series of single dominant SMV resistance genes have been identified on respective soybean chromosomes 2, 13 and 14, while one novel locus, Rsc15, underlying resistance to the virulent SMV strain SC15 from soybean cultivar RN-9 has been recently mapped to a 14.6-cM region on chromosome 6. However, candidate gene has not yet been identified within this region. In the present study, we aimed to fine map the Rsc15 region and identify candidate gene(s) for this invaluable locus. High-resolution fine-mapping revealed that the Rsc15 gene was located in a 95-kb genomic region which was flanked by the two simple sequence repeat (SSR) markers SSR_06_17 and BARCSOYSSR_06_0835. Allelic sequence comparison and expression profile analysis of candidate genes inferred that the gene Glyma.06g182600 (designated as GmPEX14) was the best candidate gene attributing for the resistance of Rsc15, and that genes encoding receptor-like kinase (RLK) (i.e., Glyma.06g175100 and Glyma.06g184400) and serine/threonine kinase (STK) (i.e., Glyma.06g182900 and Glyma.06g183500) were also potential candidates. High correlations were established between the relative expression level of GmPEX14 and the hydrogen peroxide (H2O2) concentration and activities of catalase (CAT) and peroxidase (POD) during the early stages of SMV-SC15 infection in RN-9. The results of the present study will be useful in marker-assisted breeding for SMV resistance and will lead to further understanding of the molecular mechanisms of host resistance against SMV.


Assuntos
Resistência à Doença/genética , Glycine max/genética , Doenças das Plantas/genética , Potyvirus , Alelos , Mapeamento Cromossômico , Genes Dominantes , Genes de Plantas , Genótipo , Repetições de Microssatélites , Doenças das Plantas/virologia , Glycine max/virologia
3.
Chem Commun (Camb) ; 60(51): 6496-6499, 2024 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-38836703

RESUMO

Cobalt substitution for manganese sites in Na0.44MnO2 initiates a dynamic structural evolution process, yielding a composite cathode material comprising intergrown P2 and P3 phases. The novel P2/P3 composite cathode exhibits a reversible phase transition process during Na+ extraction/insertion, showcasing its attractive battery performance in sodium-ion batteries.

4.
Opt Express ; 20(8): 9328-34, 2012 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-22513645

RESUMO

Standing wave effect of applied electrical field on optical modulation in multiple-cascaded integration (CI) electroabsorption modulator (EAM) and high-impedance transmission line (HITL) has been investigated in this paper. As modulation frequency is increased to the scale that electrical wavelength is in the order of optical modulator length, multiple electrical reflection and self-interference on impedance-mismatch boundaries becomes significant, leading to strong position-dependent field distribution and degrading modulation bandwidth. Sharp bandwidth roll of electrical-optical (EO) conversion by standing wave has been found experimentally in CI structure, consistent with simulation results. By comparing different segment number and length of CI- structure, larger section number of design can overcome such problem to get more flatten bandwidth response. Such simple CI for 300µm long EAM has been demonstrated with flat EO response of -3dB drop 45GHz and -10dB microwave reflection (up to 65GHz) in 6-segement device, suggesting this scheme design is quite useful for efficient broad band modulation.

5.
Opt Express ; 20(20): 22872-7, 2012 Sep 24.
Artigo em Inglês | MEDLINE | ID: mdl-23037436

RESUMO

This work proposes an electrically tunable infrared light source based on a new compact structure, i.e., an AlGaInAs semiconductor multiple quantum well (MQW) integrated with a liquid crystal Fabry-Pérot filter. The AlGaInAs MQW is used as a luminance layer that emits broadband light. By sandwiching the AlGaInAs and LC material with two conducting mirrors, the active light source with an optical filter can be tuned with a wide wavelength range. The filter filled with nematic liquid crystal enables continuous tuning of emission along the extraordinary mode and provides a 58 nm tuning range with a bias of 14 V. The simulation results of wavelength and tunability are consistent with the experimental results. Cholesteric liquid crystal with a planar texture is also used to examine the properties of the tunable light source. Under an electric field, all the helical liquid crystal molecules tend to be aligned parallel to the field. The variation of the refractive index is normal to the substrate surface, and the polarization-independent tuning range is 41 nm. The wide tuning range and the polarization properties observed when NLC and CLC are respectively incorporated into the AlGaInAs based Fabry-Pérot cavity suggest that this integration scheme has potential for applying to optical communication system.


Assuntos
Filtração/instrumentação , Lentes , Iluminação/instrumentação , Cristais Líquidos/química , Refratometria/instrumentação , Semicondutores , Desenho de Equipamento , Análise de Falha de Equipamento , Raios Infravermelhos
6.
Spectrochim Acta A Mol Biomol Spectrosc ; 72(1): 198-203, 2009 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-19027353

RESUMO

A novel bis-pyrazolyl-carboxyl ligand, 2,6-bis(5-methyl-3-carboxypyrazol-1-ylmethyl)pyridine (L), was designed and synthesized and its several lanthanide(III) complexes Eu(III), Tb(III), Sm(III) and Gd(III) were successfully prepared and characterized in detail based on elemental analysis, infrared, mass, proton nuclear magnetic resonance spectroscopy and TG-DTA studies. Analysis of the IR spectra suggested that each of the lanthanide metal ions coordinated to the ligand via the carbonyl oxygen atoms and the nitrogen atom of the pyridine ring and pyrazole rings. The fluorescence spectra exhibits that the Tb(III) complex and the Eu(III) complex display characteristic metal-centered fluorescence in solid state while ligand fluorescence is completely quenched. However, the Tb(III) complex displays more effective fluorescence than the other complexes, which is attributed to especial effectivity in transferring energy from the lowest triplet energy level of the ligand (L) onto the excited state ((5)D(4)) of Tb(III).


Assuntos
Elementos da Série dos Lantanídeos/química , Elementos da Série dos Lantanídeos/síntese química , Pirazóis/química , Pirazóis/síntese química , Piridinas/química , Piridinas/síntese química , Análise Diferencial Térmica , Ligantes , Espectrometria de Fluorescência , Espectrofotometria Infravermelho , Temperatura , Termogravimetria
7.
Artigo em Inglês | MEDLINE | ID: mdl-19162537

RESUMO

Two novel pyridine-2,6-dicarboxylic acid derivatives of mono-beta-diketone, methyl 6-benzoylacetyl-2-pyridinecarboxylate (MBAP) and 6-benzoylacetyl-2-pyridinecarboxylic acid (BAPA) and their Eu(III) and Tb(III) complexes were synthesized and characterized by elemental analysis, FT-IR, (1)H NMR and TG-DTG. Moreover, their Eu(III) and Tb(III) complexes using 1,10-phenanthroline as a secondary ligand were prepared and characterized. The luminescence properties of these complexes in solid state were investigated in detail. The results suggested that Tb(III) complexes exhibit more efficient luminescence than Eu(III) complexes, the fluorescence intensity of Ln(III) complexes with BAPA is about twice as strong as that of Ln(III) complexes with MBAP, the fluorescence of mono-beta-diketone complexes using 1,10-phenanthroline as a secondary ligand was prominently higher than that of complexes without adding 1,10-phenanthroline, and the ligand BAPA is an excellent sensitizer to Eu(III) and Tb(III) ion.


Assuntos
Európio/química , Cetonas/química , Fenantrolinas/química , Térbio/química , Reagentes de Ligações Cruzadas/química , Ligantes , Estrutura Molecular
8.
Spectrochim Acta A Mol Biomol Spectrosc ; 71(2): 371-6, 2008 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-18325829

RESUMO

A novel ligand, N2,N6-bis[2-(3-methylpyridyl)]pyridine-2,6-dicarboxamide (L2) and the corresponding Eu(III) and Tb(III) hydrochlorate complexes have been synthesized and characterized in detail based on elemental analysis, IR and NMR. The crystal and molecular structure of the complexes was determined by X-ray crystallography. The Eu(III) and Tb(III) ions were found to coordinate to the amido nitrogen atoms and pyridine nitrogen atoms. The luminescence properties of lanthanide complexes in solid state, in different solutions and in different pH value were investigated. The result shows that Tb(III) complexes exhibit more efficient luminescence than Eu(III) complexes, and the ligand (L2) is an excellent sensitizer to Tb(III) ion.


Assuntos
Európio/química , Ácidos Nicotínicos/química , Piridinas/química , Térbio/química , Concentração de Íons de Hidrogênio , Luminescência , Medições Luminescentes , Modelos Moleculares , Estrutura Molecular , Solventes , Espectrofotometria Infravermelho
9.
Spectrochim Acta A Mol Biomol Spectrosc ; 71(2): 321-5, 2008 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-18262837

RESUMO

A novel bis-beta-diketone organic ligand, 1,1'-(2,6-bispyridyl)bis-3-(p-methoxyphenyl)-1,3-propanedione (L1) and its derivatives, a novel bispyrazole ligand, 2,6-bis(5-(4-methoxyphenyl)-1H-pyrazol-3-yl)pyridine (L2) were designed and synthesized and their complexes with Tb(III) ion were successfully prepared. The ligands and the corresponding metal complexes were characterized by elemental analysis, infrared, proton nuclear magnetic resonance spectroscopy and TG-DTA. Analysis of the IR spectra suggested that the lanthanide metal ion Tb(III) coordinated to the ligands via the nitrogen atom of the pyridine ring and the carbonyl oxygen atoms for ligand L1 and the nitrogen atom of the pyrazole ring for ligand L2. The fluorescence properties of the two complexes in solid state were investigated and it was discovered that the Tb(III) ions could be sensitized by both the ligand (L1) and ligand (L2) to some extent. In particular, the complex of ligand (L2) is a better green luminescent material that could be used as a candidate material in organic light-emitting devices (OLEDs) since it could be much better sensitized by the ligand (L2), and the fluorescence intensity of Tb(III) complex of L2 are almost as twice strong as L1's.


Assuntos
Corantes Fluorescentes/síntese química , Cetonas/química , Pirazóis/química , Térbio/química , Corantes Fluorescentes/química , Ligantes , Estrutura Molecular , Espectrometria de Fluorescência , Espectrofotometria Infravermelho , Temperatura
10.
Spectrochim Acta A Mol Biomol Spectrosc ; 71(1): 209-14, 2008 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-18280202

RESUMO

Two novel ligands containing two pyridine-2,6-dicarboxylic acid conjugative units, 4-(2-(2,6-dicarbox-ypyridin-4-yl)vinyl)pyridine-2,6-dicarboxylic acid (L1) and 4-(4-(2-(2,6-dicarboxypyridin-4-yl)vinyl)styryl)pyridine-2,6-dicarboxylic acid (L2) and their complexes with Tb(III) have been synthesized and characterized by elemental analysis, IR spectra and NMR. The ligand synthetic route was optimized and the yield of ligands reached over 78% as a result of the Wittig-Horner reaction used. The fluorescent intensities of these complexes with corresponding complexes with single pyridine-2,6-dicarboxylic acid unit was compared. The result has shown that the ligands with two pyridine-2,6-dicarboxylic acid units are the excellent sensitizers to lanthanide fluorescence. Also, we investigated the fluorescence properties of these complexes in different solution and in different pH value. Due to their excellent green-emmiter, they would be a potential candidate material for applications in organic light-emitting devices and medical diagnosis.


Assuntos
Ácidos Carboxílicos/análise , Piridinas/análise , Piridinas/química , Espectrometria de Fluorescência/métodos , Corantes Fluorescentes/farmacologia , Concentração de Íons de Hidrogênio , Ligantes , Luz , Espectroscopia de Ressonância Magnética , Modelos Químicos , Óxidos/química , Piridinas/farmacologia , Espectrofotometria Infravermelho/métodos , Térbio/química
11.
Artigo em Inglês | MEDLINE | ID: mdl-17625961

RESUMO

A novel bis-beta-diketon ligand, 1,1'-(2,6-bispyridyl)bis-3-phenyl-1,3-propane-dione (L), was designed and synthesized and its complexes with Eu(III), Tb(III), Sm(III) and Gd(III) ions were successfully prepared. The ligand and the corresponding metal complexes were characterized by elemental analysis, and infrared, mass and proton nuclear magnetic resonance spectroscopy. Analysis of the IR spectra suggested that each of the lanthanide metal ions coordinated to the ligand via the carbonyl oxygen atoms and the nitrogen atom of the pyridine ring. The fluorescence properties of these complexes in solid state were investigated and it was discovered that all of the lanthanide ions could be sensitized by the ligand (L) to some extent. In particular, the Tb(III) complex was an excellent green-emitter and would be a potential candidate material for applications in organic light-emitting devices (OLEDs) and medical diagnosis.


Assuntos
Corantes Fluorescentes/síntese química , Cetonas/química , Elementos da Série dos Lantanídeos/química , Corantes Fluorescentes/química , Ligantes , Estrutura Molecular , Espectrofotometria , Espectrofotometria Infravermelho
12.
Chem Commun (Camb) ; (11): 1121-3, 2007 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-17347712

RESUMO

Through a new pyrazine-modulated penta-pyridyl-tetraamine ligand, H(4)N(9)-mpz, linear nonachromium(II) complexes with four quadruple metal-metal bonds were successfully obtained, and their structure, magnetic and electrochemistry properties were studied.

13.
Dalton Trans ; 44(9): 3997-4002, 2015 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-25612008

RESUMO

A new silver(I)-alkynyl cluster with a [Eu(W5O18)2](9-) polyoxoanionic core of [Ag42{Eu(W5O18)2}((t)BuC≡C)28Cl4] [OH]·H2O (1) has been designed and synthesized. The [Eu(W5O18)2](9-) polyoxoanion acts as a template to induce the formation of the surrounding 42-core Ag(I) cage. Due to the hydrophobic silver(I)-alkynyl shell, 1 features an unusual fluorescence enhancement as compared to the precursor of the [Eu(W5O18)2](9-) polyoxoanionic core. Interestingly, the silver ions in the shell silver(I)-alkynyl cage can only be reduced to silver atoms by irradiation with high energy UV light (2 kW). Upon high UV irradiation, fluorescence quenching of 1 has been observed. Moreover, the solution fluorescence of 1 can be modulated by addition of S(2-) ions into the system, which also leads to the fluorescence quenching phenomenon. The successful synthesis of 1 demonstrates a new route to the detection of high energy UV irradiation or S(2-) ions by elaborate design of fluorescence quenching of silver(I)-alkynyl clusters.


Assuntos
Európio/química , Prata/química , Compostos de Tungstênio/química , Európio/efeitos da radiação , Fluorescência , Prata/efeitos da radiação , Compostos de Tungstênio/efeitos da radiação , Raios Ultravioleta
14.
Zhongguo Shi Yan Xue Ye Xue Za Zhi ; 21(4): 1027-31, 2013 Aug.
Artigo em Zh | MEDLINE | ID: mdl-23998606

RESUMO

The aim of this study was to investigate the radioprotective effect of recombinant murine interleukin 12 (rmIL-12) on mice irradiated by γ-ray. Fifty- six BALB/c mice were totally irradiated by 6.0 Gy of (60)Co γ-ray and randomly divided into irradiation control group,rmIL-12 treated group and recombinant murine thrombopoietin (rmTPO) treated group.The 5 and 20 µg/kg of rmIL-12 were administrated intraperitoneally at 24 h before irradiation respectively (low and high dose rmIL-12 treated group), 15 µg/kg of rmTPO was administrated subcutaneously at 30 min and 24 h following irradiation in rmTPO treated group. The general conditions of mice were observed twice a day, the changes in body weight and peripheral blood cell counts were examined once every three days, bone marrow cells were collected to perform colony cultivation at day 14 and 28 after irradiation. The results showed that the general conditions of mice in rmIL-12 treated group were better than those in irradiation control group. Compared with the irradiation control group,5 and 20 µg/kg rmIL-12 treatment significantly promoted platelet recovery, resulting in less profound nadirs (15.9% vs 8.1%,18.2% vs 8.1%,P < 0.01) and rapid recovery to normal levels (11 days vs 14 days). WBC count recovery rate in rmIL-12 treated group was faster than that in the irradiation control group. The WBC and platelet count recovery rate in 5 µg/kg rmIL-12 treated group were as fast as that in the rmTPO treated group, both of which were slower than that in 20 µg/kg rmIL-12 treated group (P > 0.05). Semi-solid bone marrow cell culture also demonstrated that rmIL-12 could stimulate bone marrow cells to form more CFU-Mix than those in the irradiation control group in vitro at day 14 and 28 after irradiation(P < 0.01).There was no significant difference between rmIL-12 and rmTPO treated groups (P > 0.05), CFU-GM counts in 5 µg/kg rmIL-12 treated group and rmTPO treated group at day 28 after irradiation were higher than those in irradiation control group(P < 0.05), but less than those in 20 µg/kg rmIL-12 treated group (P < 0.05). It is concluded that rmIL-12 has a significant radioprotective effect on mice irradiated by γ-ray.


Assuntos
Interleucina-12/uso terapêutico , Lesões Experimentais por Radiação/sangue , Protetores contra Radiação/uso terapêutico , Animais , Plaquetas , Raios gama , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Contagem de Plaquetas , Proteínas Recombinantes/uso terapêutico , Trombopoetina/uso terapêutico , Irradiação Corporal Total
15.
Zhongguo Shi Yan Xue Ye Xue Za Zhi ; 20(4): 995-9, 2012 Aug.
Artigo em Zh | MEDLINE | ID: mdl-22931671

RESUMO

The aim of this study is to observe the therapeutic effect of recombinant murine interleukin 12 (rmIL-12) combining with granulocyte colony stimulating factor (G-CSF) on mice irradiated by γ-rays. 56 BALB/c mice were totally irradiated by 6.0 Gy of (60)Co γ-ray and randomly divided into irradiation control group, rmIL-12 treatment group, G-CSF treatment group and combination therapy (rmIL-12 plus G-CSF) group. rmIL-12 20 µg/kg was administrated intraperitoneally at 1 h following irradiation, and was administrated every 3 days after irradiation for 4 times in rmIL-12 treatment group. G-CSF 100 µg/kg was administrated subcutaneously the 2 h following irradiation for 14 d in G-CSF treatment group. The dose and method of rmIL-12 and G-CSF in combination therapy group were same as in rmIL-12 group and G-CSF group. The general status of mice were observed twice a day, the changes in body weight, peripheral blood cell (WBC and Plt) counts were examined once every three days, bone marrow cells were collected to perform colony cultivation on day 14 and 28 after irradiation. The results showed that WBC count recovery time in combination therapy group was significantly earlier than that of the control group (7 d vs 11 d), WBC count recovery velocity in the combination therapy group was no significant different from that of the G-CSF treatment group. Combined therapy significantly promoted Plt count recovery, resulting in less profound nadirs (16.5% vs 8.1%, P < 0.01) and rapid recovery to normal levels (11 d vs 14 d), Plt count recovery velocity in the combination therapy group was no significant different from that of the rmIL-12 treatment group. Culture of bone marrow cells in semi-solid medium also demonstrated that combination of rmIL-12 and G-CSF could stimulate bone marrow cells to form more CFU-GM and CFU-Mix than those of the irradiation control group in vitro on day 14 and 28 after irradiation (P < 0.05). It is concluded that the combination of rmIL-12 and G-CSF can significantly accelerate the recovery of hematopoietic function in mice with acute radiation sickness.


Assuntos
Fator Estimulador de Colônias de Granulócitos/uso terapêutico , Interleucina-12/uso terapêutico , Lesões por Radiação/tratamento farmacológico , Animais , Raios gama , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Lesões Experimentais por Radiação/tratamento farmacológico , Proteínas Recombinantes/uso terapêutico
16.
ACS Appl Mater Interfaces ; 1(12): 2821-8, 2009 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-20356162

RESUMO

We have systematically studied the self-organization of poly(3-hexylthiophene) (P3HT), an electrochromic material, upon control of the solvent evaporation rate. We characterized these polymer films using atomic force microscopy and X-ray diffraction measurements. Well-ordered P3HT structures were developed after solvent annealing; these highly crystalline structures exhibited enhanced electrochromic contrast and reduced resistance within the film, leading to larger coloration efficiencies and faster switching times. The optical contrast (Delta%T), coloration efficiency, and switching time of the P3HT films increased from 54.2%, 182.6 cm(2) C(-1), and 5.3 s, respectively, prior to solvent annealing to 64.8%, 293.5 cm(2) C(-1), and 3.2 s, respectively, after application of the solvent-annealing conditions.

17.
Dalton Trans ; (47): 6808-16, 2008 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-19153628

RESUMO

Pentacobalt EMACs [Co(5)(mu(5)-dpzpda)(4)X(2)] (X = Cl(-) (), NCS(-) ()) with fine-tuning of the supporting ligand based on the tripyridyldiamine ligand, N,N'-di(pyrazin-2-yl)pyridine-2,6-diamine (H(2)dpzpda), and their reduced form (Ph(4)P)[Co(5)(mu(5)-dpzpda)(4)X(2)] (X = Cl(-) (), NCS(-) ()) were first synthesized and structurally characterized. The structures of showed direct Co-Co bonds with Co-Co distances in the range 2.2385(7)-2.2888(15) A, and valence electrons delocalized through the whole metal chain with distances of longer than 9.06 A. The distances of the inner Co-Co bonds and the Co-axial ligands became longer after reduction, whereas no significant change was observed in the distances of the outer Co-Co bonds and Co-N (supporting ligand) bonds, which was consistent with the MO analysis. Electrochemical studies on both and showed one reversible oxidation and one reversible reduction at E(1/2) = +0.82 and -0.05 V for , and at E(1/2) = +0.89 and +0.02 V for , respectively. The redox reactions of the thiocyanate complex happened at higher potentials than the chloride complex . A magnetism study of revealed anomalous magnetic behaviour similar to that of heptacobalt EMACs, and a deviation from the Curie-Weiss law was observed. The chi(M)T value at 300 K is 0.84 and 1.16 emu K mol(-1) for and , respectively, suggesting spin-equilibrium or a spin-admixture between doublet and quartet states arising from the Boltzmann distribution over different energy levels. Similar results were obtained for and , showing intermediate chi(M)T values between a diamagnetic and a triplet state of 0.15-0.96 emu K mol(-1) in the temperature range 5-300 K. The structural and magnetic results were interpreted through an EHMO study.

18.
Dalton Trans ; (27): 2898-907, 2007 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-17607404

RESUMO

Here we designed and synthesized a new ligand, di(2-pyrazyl)amine (Hdpza) (1) and studied its coordination modes and the corresponding complexes with Cu(II), Co(II), Ni(II) and Cr(II). Hdpza is an analogue of the well-studied di(2-pyridyl)amine (Hdpa) ligand, which was used to generate the first extended metal atom chain. Three types of coordination modes were found: anti-anti style which resulted in a mononuclear compound [Cu(Hdpza)(2)(H(2)O)(2)](ClO(4))(2) (2); anti-syn which was observed in a complex for the first time and resulted in a 2-D coordination polymer [Co(mu(2)-Hdpza)(2)(NCS)(2)] (3); and syn-syn type which was observed in extended metal atom chains [Ni(3)(mu(3)-dpza)(4)Cl(2)] (4), [Ni(3)(mu(3)-dpza)(4)(NCS)(2)] (5) and [Cr(3)(mu(3)-dpza)(4)Cl(2)] (6). Weak antiferromagnetic coupling via Hdpza was observed in 3, whereas magnetic studies on extended metal atom chains 4 and 5 revealed that the interaction parameter was more than -200 cm(-1). Electrochemistry showed that the extended metal atom chains 4-6 are much more stable to oxidation than the Hdpa complexes, and are able to undergo reduction.

19.
Protein Expr Purif ; 45(1): 54-9, 2006 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-16122941

RESUMO

To investigate the properties of wheat cytochrome P450 and the characteristics of herbicide metabolism by cytochrome P450 in vitro, deeply understand the mechanisms of herbicide selectivity, recombinant wheat cytochrome P450 monooxygenase (CYP71Cv1) heterologously expressed in yeast was purified by DE-52 cellulose chromatography and fast protein liquid chromatography (FPLC) with Mono-Q column. The degree of purification was 1366-fold. The specific activity of purified cytochrome P450 reached to 512 nmol min-1 mg-1 protein with herbicide chlorsulfuron as substrate. The purified cytochrome P450 exhibited one band in sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis, and the molecular mass was 52.5 kDa. Kinetic parameter was determined in vitro. The Km values for chlorsulfuron and triasulfuron were 57 (+/-15) and 38 (+/-16) microM, respectively; and Vmax for chlorsulfuron and triasulfuron were 4.1 (+/-0.7) and 2.7 (+/-0.5) nmol min-1 mg-1protein in vitro, respectively.


Assuntos
Sistema Enzimático do Citocromo P-450 , Saccharomyces cerevisiae/genética , Triticum/enzimologia , Sistema Enzimático do Citocromo P-450/química , Sistema Enzimático do Citocromo P-450/genética , Sistema Enzimático do Citocromo P-450/isolamento & purificação , Eletroforese em Gel de Poliacrilamida , Expressão Gênica , Herbicidas/química , Técnicas In Vitro , Cinética , Microssomos/química , Microssomos/enzimologia , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/isolamento & purificação , Saccharomyces cerevisiae/metabolismo , Sensibilidade e Especificidade , Sulfonamidas/química , Fatores de Tempo , Triazinas/química , Triticum/genética
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