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1.
Chemphyschem ; 22(17): 1754-1768, 2021 09 03.
Artigo em Inglês | MEDLINE | ID: mdl-34085351

RESUMO

The effects of the vibronic coupling in quantum cellular automata (QCA) based on the square planar mixed valence (MV) molecular cells comprising four paramagnetic centers (spin cores) and two excess mobile electrons are analyzed in the important particular case when the Coulomb energy gap between the ground antipodal diagonal-type two-electron configurations and the excited side-type configurations considerably exceeds both the one-electron transfer parameter (strong U-limit) and the vibronic stabilization energy. Under such conditions the developed model involves the second-order double exchange, the Heisenberg-Dirac-Van Vleck (HDVV) exchange and the vibronic coupling of the excess electrons with the molecular B1g -vibration composed of four full-symmetric local vibrations. The latter interaction is shown to significant amplify the ability of the electric field produced by the driver-cell to polarize the excess electrons in the working cell, which can be termed "the effect of the vibronic enhancement of the cell-cell interaction". This effect leads to a redetermination of the conditions for switching between different spin-states, as well as to a significant change in the shapes of the cell-cell response functions. The obtained results demonstrate the importance of the vibronic coupling in all aspects (such as description of a free cell and cell-cell response) of the theory of molecular QCA based on MV clusters.

2.
J Phys Chem A ; 119(38): 9844-56, 2015 Sep 24.
Artigo em Inglês | MEDLINE | ID: mdl-26305153

RESUMO

Here we describe a new vibronic model of mixed valence (MV) dimer inspired by the conventional Piepho, Krausz, and Schatz (PKS) approach. We attempted to partially lift the main restriction of the PKS model dealing with the vibronically independent moieties of a MV molecule. The refined version of the PKS model in which the bridging ligands are included deals with the three main interactions: electron transfer (integral t0) related to the high-symmetric ligand configuration, on-site vibronic coupling (parameter υ) arising from the modulation of the crystal field on the metal sites by the breathing displacements of their nearest ligand surroundings, and intercenter vibronic coupling (parameter ζ) describing the dependence of the electron transfer on ligand positions in the course of their breathing movement. We apply the modified model to the analysis of the adiabatic potentials and electronic density distributions in the minima of their lower sheets for the cases of one-electron MV dimer with long and short bridges and for the two-electron MV dimer exhibiting a valence disproportionation effect. The inclusion of the intercenter interaction in addition to the conventional PKS coupling is shown to produce a strong effect on the degree of localization in MV dimers and, in particular, on the assignments to the Robin and Day classes and on the conditions of stabilization of valence disproportionated states in bielectron transfer systems.

3.
J Am Chem Soc ; 134(36): 14982-90, 2012 Sep 12.
Artigo em Inglês | MEDLINE | ID: mdl-22894703

RESUMO

A robust, stable and processable family of mononuclear lanthanoid complexes based on polyoxometalates (POMs) that exhibit single-molecule magnetic behavior is described here. Preyssler polyanions of general formula [LnP(5)W(30)O(110)](12-) (Ln(3+) = Tb, Dy, Ho, Er, Tm, and Yb) have been characterized with static and dynamic magnetic measurements and heat capacity experiments. For the Dy and Ho derivatives, slow relaxation of the magnetization has been found. A simple interpretation of these properties is achieved by using crystal field theory.

4.
Phys Rev Lett ; 108(24): 247213, 2012 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-23004325

RESUMO

We report ac susceptibility and continuous wave and pulsed EPR experiments performed on GdW10 and GdW30 polyoxometalate clusters, in which a Gd3+ ion is coordinated to different polyoxometalate moieties. Despite the isotropic character of gadolinium as a free ion, these molecules show slow magnetic relaxation at very low temperatures, characteristic of single molecule magnets. For T≲200 mK, the spin-lattice relaxation becomes dominated by pure quantum tunneling events, with rates that agree quantitatively with those predicted by the Prokof'ev and Stamp model [Phys. Rev. Lett. 80, 5794 (1998)]. The sign of the magnetic anisotropy, the energy level splittings, and the tunneling rates strongly depend on the molecular structure. We argue that GdW30 molecules are also promising spin qubits with a coherence figure of merit Q(M)≳50.

5.
Dalton Trans ; 50(17): 5931-5942, 2021 May 04.
Artigo em Inglês | MEDLINE | ID: mdl-33949535

RESUMO

The 1 : 2 and 1 : 1 Co(ii) complexes of the L ligand (L = 6-(3,5-diamino-2,4,6-triazinyl)2,2'-bipyridine) with formulas [CoII(L)2](ClO4)2·0.5MeCN·Et2O (1) and [CoII(L)(CH3CN)2(H2O)](ClO4)2·MeCN (2) have been prepared. The structural and magnetic characterization of the two compounds shows that they contain octahedral high-spin Co(ii) and present a field-induced slow relaxation of the magnetization. 1 has been inserted into a bimetallic oxalate-based network leading to a novel achiral 3D compound of formula [CoII(L)2][MnIICrIII(ox)3]2·(solvate) (3) exhibiting ferromagnetic ordering below 4.6 K. EPR measurements suggest a weak magnetic coupling between the two sublattices.

6.
J Comput Chem ; 31(6): 1321-32, 2010 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-20044799

RESUMO

We present a FORTRAN code based on a new powerful and efficient computational approach to solve the double exchange problem for high-nuclearity MV clusters containing arbitrary number of localized spins and itinerant electrons. We also report some examples in order to show the possibilities of the program.

7.
Inorg Chem ; 49(17): 8073-7, 2010 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-20677766

RESUMO

To explain the single-molecule magnet behavior of the mononuclear complex [(tpaMes)Fe](-) we have developed a model that takes into account the trigonal ligand field splitting of the atomic (5)D term of the Fe(II) ion, and the spin-orbital splitting and mixing of the ligand field terms. The ground ligand field term is shown to be the orbital doublet (5)E possessing an unquenched orbital angular momentum. We demonstrate that the splitting of this term cannot be described by the conventional zero-field splitting Hamiltonian proving thus the irrelevance of the spin-Hamiltonian formalism in the present case. The first-order orbital angular momentum is shown to lead to the strong magnetic anisotropy with the trigonal axis being the easy axis of the magnetization.

8.
Inorg Chem ; 48(10): 4557-68, 2009 May 18.
Artigo em Inglês | MEDLINE | ID: mdl-19371089

RESUMO

A general approach to the problem of electron delocalization in the high-nuclearity mixed-valence (MV) clusters containing an arbitrary number of localized spins and itinerant electrons is developed. Along with the double exchange, we consider the isotropic magnetic exchange between the localized electrons as well as the Coulomb intercenter repulsion. As distinguished from the previous approaches dealing with the MV systems in which itinerant electrons are delocalized over all constituent metal sites, here, we consider a more common case of systems exhibiting partial delocalization and containing several delocalized domains. Taking full advantage of the powerful angular momentum technique, we were able to derive closed form analytical expressions for the matrix elements of the full Hamiltonian. These expressions provide an efficient tool for treating complex mixed-valence systems, because they contain only products of 6j-symbols (that appear while treating the delocalized parts) and 9j-symbols (exchange interactions in localized parts) and do not contain high-order recoupling coefficients and 3j-symbols that essentially constrained all previous theories of mixed valency. The approach developed here is accompanied by an efficient computational procedure that allows us to calculate the bulk thermodynamic properties (magnetic susceptibility, magnetization, and magnetic specific heat) of high-nuclearity MV clusters. Finally, this approach has been used to discuss the magnetic properties of the octanuclear MV cluster [Fe(8)(mu(4)-O)(4)(4-Cl-pz)(12)Cl(4)](-) and the diphthalocyanine chains [YPc(2)].CH(2)Cl(2) and [ScPc(2)].CH(2)Cl(2) composed of MV dimers interacting through the magnetic exchange and Coulomb repulsion.


Assuntos
Magnetismo , Modelos Químicos , Teoria Quântica , Elétrons , Modelos Moleculares
9.
Dalton Trans ; 46(8): 2680-2689, 2017 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-28170015

RESUMO

The Fe(ii) complex of the L1 ligand (L1 = 6-(3,5-diamino-2,4,6-triazinyl)-2,2'-bipyridine) has been used as a templating cation for the growth of oxalate-based networks. The magnetic characterization of the [FeII(L1)2](ClO4)2·CH3CN (1) precursor in the solid state has been performed for the first time showing that the low-spin (LS) state is predominating from 2 to 400 K with 10% of Fe(ii), which undergoes a gradual and irreversible spin-crossover above 350 K. 1 presents the LIESST effect with a photo-conversion close to 25% and a T(LIESST) of 49 K. During the preparation of 1, a secondary product of the formula [FeII(L1)(CH3CN)2(H2O)](ClO4)2·CH3CN (2) has been obtained. The magnetic characterization of 2 shows that it contains high-spin (HS) Fe(ii). 1 has afforded two novel oxalate-based compounds, the 2D compound of the formula [FeII(L1)2][MnIICrIII(ox)3]2·(CH3NO2)6·(CH3OH)·(H2O)2 (3) and the 3D compound of the formula [FeII(L1)2][MnIICrIII(ox)3]2·(CH3CN)3 (4), which have been obtained by changing the synthetic conditions. The magnetic properties show that in 3 the inserted Fe(ii) cation remains in the LS state from 2 to 340 K and presents a partial and irreversible spin-crossover of ∼20% at higher temperatures. In 4, most of the Fe(ii) complexes remain in the LS state from 2 to 230 K and present a partial and irreversible spin-crossover of ∼50% from 230 to 400 K. 3 and 4 do not present the LIESST effect.

10.
Oncotarget ; 8(9): 15294-15306, 2017 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-28122331

RESUMO

Penile carcinoma (PeCa) is an important public health issue in poor and developing countries, and has only recently been explored in terms of genetic and epigenetic studies. Integrative data analysis is a powerful method for the identification of molecular drivers involved in cancer development and progression. miRNA and mRNA expression profiles followed by integrative analysis were investigated in 23 PeCa and 12 non-neoplastic penile tissues (NPT). Expression levels of eight miRNAs and 10 mRNAs were evaluated in the same set of samples used for microarray and in a validation set of cases (PeCa = 36; NPT = 27). Eighty-one miRNAs and 2,697 mRNAs were identified as differentially expressed in PeCa. Integrative data analysis revealed 255 mRNAs potentially regulated by 68 miRNAs. Using RT-qPCR, eight miRNAs and nine transcripts were confirmed as altered in PeCa. We identified that MMP1, MMP12 and PPARG and hsa-miR-31-5p, hsa-miR-224-5p, and hsa-miR-223-3p were able to distinguish tumors from NPT with high sensitivity and specificity. Higher MMP1 expression was detected as a better predictor of lymph node metastasis than the clinical-pathological data. In addition, PPARG and EGFR were highlighted as potential pathways for targeted therapy in PeCa. The analysis based on HPV positivity (7 of 23 cases) revealed five miRNA and 13 mRNA differentially expressed. Although in a limited number of cases, HPV positive PeCa presented less aggressive phenotype in comparison with negative cases. Overall, an integrative analysis using mRNA and miRNA profiles revealed markers related with tumor development and progression. Furthermore, MMP1 expression level was a predictive marker for lymph node metastasis in patients with PeCa.


Assuntos
Biomarcadores Tumorais/genética , Regulação Neoplásica da Expressão Gênica , MicroRNAs/genética , Neoplasias Penianas/genética , RNA Mensageiro/genética , Transdução de Sinais/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Análise por Conglomerados , Diagnóstico Diferencial , Perfilação da Expressão Gênica/métodos , Humanos , Masculino , Metaloproteinase 1 da Matriz/genética , Metaloproteinase 12 da Matriz/genética , Pessoa de Meia-Idade , PPAR gama/genética , Neoplasias Penianas/diagnóstico , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Sensibilidade e Especificidade
11.
J Appl Physiol (1985) ; 98(1): 83-92, 2005 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-15286045

RESUMO

This study questioned the effect of living and training at moderate altitude on cardiac morphological and functional adaptations and tested the incidences of potential specific adaptations compared with aerobic sea level training on maximal left ventricular performance. Sea level-native rats were randomly assigned to N (living in normoxia), NT (living and training 5 days/wk for 5 wk in normoxia), CH (living in hypoxia, 2,800 m), and CHT (living and training 5 days/wk for 5 wk in hypoxia, 2,800 m) groups. Cardiac adaptations were evaluated throughout the study period by Doppler echocardiography. Maximal stroke volume (LV(SVmax)) was measured during volume overloading before and after the study period. Finally, at the end of the study period, passive pressure-volume relationships on isolated heart and cardiac weighing were obtained. Altitude training resulted in a specific left ventricular (LV) remodeling compared with NT, characterized by an increase in wall thicknesses without any alteration in internal dimensions. These morphological adaptations associated with hypoxia-induced alterations in pulmonary outflow and preload conditions led to a decrease in LV filling and subsequently no improvement in LV performance during resting physiological conditions in CHT compared with NT. Such a lack of improvement was confirmed during volume overloading that simulated maximal effort (LV(SVmax) pretest: NT = 0.58 +/- 0.05, CHT = 0.57 +/- 0.08 ml; posttest: NT = 0.72 +/- 0.06, CHT = 0.58 +/- 0.07 ml; NT vs. CHT in posttest session, P < 0.05). Maximal aerobic velocities increased to the same extent in NT and CHT rats despite marked polycythemia in the latter. The lack of LV(SVmax) improvement resulting from altitude training-induced cardiac morphological and functional adaptations could be responsible for this phenomenon.


Assuntos
Altitude , Ventrículos do Coração/diagnóstico por imagem , Condicionamento Físico Animal/métodos , Esforço Físico/fisiologia , Função Ventricular Esquerda/fisiologia , Função Ventricular , Remodelação Ventricular/fisiologia , Adaptação Fisiológica/fisiologia , Animais , Pressão Atmosférica , Coração/fisiologia , Masculino , Ratos , Volume Sistólico/fisiologia , Ultrassonografia
12.
Chem Commun (Camb) ; (21): 2172-3, 2001 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-12240097

RESUMO

A new polynuclear copper(II) complex [Cu7(OH)6Cl2(pn)6(H2O)2](C(CN)3)4Cl2 with hydroxo-bridging ligands has been prepared; the centrosymmetric cluster cation can be described as two Cu4O3Cl distorted cubane units sharing one copper cation.

13.
Clin Chim Acta ; 298(1-2): 13-28, 2000 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-10876001

RESUMO

Cardiac troponins I (cTnI) and T (cTnT) have been shown to be highly sensitive and specific markers of myocardial cell injury. The purpose of this study was to investigate the diagnostic value of cTnI and cTnT with regard to creatine kinase (CK) and lactate dehydrogenase (LD) and to determine whether they can be used for early diagnosis of myocardial damage in rats, and to examine the relationship between cTnl and cTnT release with histological examinations, using isoprenaline-induced cardiac muscle damage as an experimental model in the rat. Eighteen Wistar rats per group were treated with a single dose of either isoprenaline (iso) or with normal saline as a control group. The anti-cTnI and cTnT monoclonal antibodies (mAbs) employed in the cTnI (Access) and cTnT (Elecsys) assays cross-react with cTnI and cTnT of the rat. A highly significant rise of cTnl or cTnT was found already 2 h after iso. The time-courses of cTnI and cTnT were monophasic in form. The highest cTnI (mean+/-S.D., 1.1+/-2.3 ng/ml) and cTnT (mean+/-S.D. 3.6+/-30 ng/ml) were found 4 h after iso. cTnI and cTnT significantly increased in iso-treated rats in comparison with controls whether the differences between 2-, 4- and 6-h levels and basal levels were considered or not. The areas under cTnl and cTnT curves (AUC) (0-6 h) and the maximal cTnI and cTnT (0-6 h) after iso were significantly different from the controls. For CK and LD, no elevation in comparison with controls could be detected (except a trend for LD whether or not the difference between 6-h levels and basal levels were considered (P=0.08) and for LD AUC (0-6 h) (P=0. 059)). Correlations between maximal cTnI and cTnT and AUC were 0.69 (P=0.0001) and 0.60 (P=0.0066), respectively. Histological examinations of iso-treated rats revealed acute focal or multifocal myofibrillar degeneration of the myocardial tissue in ten out of 14 rats and showed the earliest alterations 4 h after iso in one treated rat. Only four of the controls exhibited evidence of mild changes and slight mononuclear cell infiltration. cTnl and cTnT peak values to at least 0.35 and 1.3 ng/ml, respectively, were necessary to detect histological myocardial cell injury after iso. cTnI and cTnT were found to be early markers for diagnosing iso-induced myocardial damage in comparison with CK and LD. Elevations of cTnI and cTnT appeared to relate to the severity of histologic changes after myocardial injury. Although there was a difference in the absolute concentration of results between cTnI and cTnT assays, due to a lack of standardization and heterogeneity in the cross-reactivities of mAbs to various troponin I and T forms, cTnI and cTnT can be used as easily measurable target parameters for detection of cardiotoxic and/or cardiodegenerative effects in rats.


Assuntos
Cardiomiopatias/diagnóstico , Cardiopatias/induzido quimicamente , Troponina I/sangue , Troponina T/sangue , Animais , Anticorpos Monoclonais , Cardiomiopatias/induzido quimicamente , Cardiomiopatias/patologia , Creatina Quinase/sangue , Cardiopatias/sangue , Cardiopatias/patologia , Isoproterenol , Cinética , L-Lactato Desidrogenase/sangue , Miofibrilas/patologia , Ratos , Ratos Wistar , Sensibilidade e Especificidade
14.
Clin Chim Acta ; 283(1-2): 43-56, 1999 May.
Artigo em Inglês | MEDLINE | ID: mdl-10404730

RESUMO

The study was designed to determine the time-course of cardiac troponin I (cTn-I) release in isolated and Langendorff-perfused rat hearts during hypoxia and reoxygenation (H/Reox), and after various durations of total ischemia and subsequent reperfusion (I/R). For this purpose, in H/Reox, cTn-I was measured with the conventional Access immunoassay (ng/ml) and a new immunoassay which operates at pg/ml, and compared with creatine kinase (CK), lactate dehydrogenase (LD) and cardiac troponin T (cTn-T). In I/R, cTn-I was compared with CK and LD. The anti-Tn-I mAbs used in cTn-I assays cross-react with cTn-I of the rat. A clear difference between time-courses and concentration levels of cTn-I in I/R and H/Reox models was found. In I/R, maximum release of cTn-I, CK and LD similarly occurred within minutes following reperfusion; however cTn-I did not return to baseline values. cTn-I levels were not linked to the duration of ischemia. In I/R, we were only able to detect small cTn-I concentrations. In H/Reox experiments, cTn-I, CK and LD increased time-dependently. We found higher cTn-I maximal peak levels detected with the Access immunoassay than with the new assay (median, 0.346 ng/ml per min/g dry wt vs 132 pg/ml per min/g dry wt). cTn-T maximal concentrations were lower than maximal cTn-I levels (median, 0.117 ng/ml per min/g dry wt). Time-courses of cTn-I release were roughly similar with both assays in the H/Reox model (r = 0.90). These data indicate that the cTn-I time-course is related to experimental model (I/R or H/Reox), but also likely depends on the sensitivity of cTn-I assays in such experimental conditions.


Assuntos
Hipóxia/metabolismo , Isquemia Miocárdica/metabolismo , Reperfusão Miocárdica , Miocárdio/metabolismo , Troponina I/metabolismo , Animais , Creatina Quinase/análise , Creatina Quinase/metabolismo , Imunoensaio/métodos , Técnicas In Vitro , L-Lactato Desidrogenase/análise , L-Lactato Desidrogenase/metabolismo , Ratos , Ratos Wistar , Fatores de Tempo , Troponina I/análise , Troponina T/análise , Troponina T/metabolismo
15.
Clin Chim Acta ; 329(1-2): 39-51, 2003 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-12589964

RESUMO

BACKGROUND: Cardiac troponins I (cTnI) and T (cTnT) have been shown to be highly sensitive and specific markers of myocardial cell injury. We investigated the diagnostic value of cTnI and cTnT for the diagnosis of myocardial damage in a rat model of doxorubicin (DOX)-induced cardiomyopathy, and we examined the relationship between serial cTnI and cTnT with the development of cardiac disorders monitored by echocardiography and histological examinations in this model. METHODS: Thirty-five Wistar rats were given 1.5 mg/kg DOX, i.v., weekly for up to 8 weeks for a total cumulative dose of 12 mg/kg BW. Ten rats received saline as a control group. cTnI was measured with Access(R) (ng/ml) and a research immunoassay (pg/ml), and compared with cTnT, CK-MB mass and CK. By using transthoracic echocardiography, anterior and posterior wall thickness, LV diameters and LV fractional shortening (FS) were measured in all rats before DOX or saline, and at weeks 6 and 9 after treatment in all surviving rats. Histology was performed in DOX-rats at 6 and 9 weeks after the last DOX dose and in all controls. RESULTS: Eighteen of the DOX rats died prematurely of general toxicity during the 9-week period. End-diastolic (ED) and end-systolic (ES) LV diameters/BW significantly increased, whereas LV FS was decreased after 9 weeks in the DOX group (p<0.001). These parameters remained unchanged in controls. Histological evaluation of hearts from all rats given DOX revealed significant slight degrees of perivascular and interstitial fibrosis. In 7 of the 18 rats, degeneration and myocyte vacuolisation were found. Only five of the controls exhibited evidence of very slight perivascular fibrosis. A significant rise in cTnT was found in DOX rats after cumulative doses of 7.5 and 12 mg/kg in comparison with baseline (p<0.05). cTnT found in rats after 12 mg/kg were significantly greater than that found after 7.5 mg/kg DOX. Maximal cTnI (pg/ml) and cTnT levels were significantly increased in DOX rats compared with controls (p=0.006, 0.007). cTnI (ng/ml), CK-MB mass and CK remained unchanged in DOX rats compared with controls. All markers remained stable in controls. Analysis of data revealed a significant correlation between maximal cTnT and ED and ES LV diameters/BW (r=0.81 and 0.65; p<0.0001). A significant relationship was observed between maximal cTnT and the extent of myocardial morphological changes, and between LV diameters/BW and histological findings. CONCLUSIONS: Among markers of ischemic injury after DOX in rats, cTnT showed the greatest ability to detect myocardial damage assessed by echocardiographic detection and histological changes. Although there was a discrepancy between the amount of cTnI and cTnT after DOX, probably due to heterogeneity in cross-reactivities of mAbs to various cTnI and cTnT forms, it is likely that cTnT in rats after DOX indicates cell damage determined by the magnitude of injury induced and that cTnT should be a useful marker for the prediction of experimentally induced cardiotoxicity and possibly for cardioprotective experiments.


Assuntos
Catepsina B/líquido cefalorraquidiano , Catepsinas/líquido cefalorraquidiano , Cistatinas/líquido cefalorraquidiano , Cisteína Endopeptidases/líquido cefalorraquidiano , Neoplasias Meníngeas/líquido cefalorraquidiano , Neoplasias Meníngeas/secundário , Western Blotting , Catepsina H , Contagem de Células , Líquido Cefalorraquidiano/citologia , Cistatina C , Ensaio de Imunoadsorção Enzimática , Humanos , Imuno-Histoquímica , Leucemia/patologia , Neoplasias Meníngeas/patologia , Metástase Neoplásica
16.
Inorg Chem ; 38(26): 6081-6088, 1999 Dec 27.
Artigo em Inglês | MEDLINE | ID: mdl-11671316

RESUMO

A general solution of the exchange problem in the high-nuclearity spin clusters (HNSC) containing arbitrary number of exchange-coupled centers and topology is developed. All constituent magnetic centers are supposed to possess well-isolated orbitally non-degenerate ground states so that the isotropic Heisenberg-Dirac-Van Vleck (HDVV) term is the leading part of the exchange spin Hamiltonian. Along with the HDVV term, we consider higher-order isotropic exchange terms (biquadratic exchange), as well as the anisotropic terms (anisotropic and antisymmetric exchange interactions and local single-ion anisotropies). All these terms are expressed as irreducible tensor operators (ITO). This allows us to take full advantage of the spin symmetry of the system. At the same time, we have also benefitted by taking into account the point group symmetry of the cluster, which allows us to work with symmetrized spin functions. This results in an additional reduction of the matrices to diagonalize. The approach developed here is accompanied by an efficient computational procedure that allows us to calculate the bulk magnetic properties (magnetic susceptibility, magnetization, and magnetic specific heat) as well as the spectroscopic properties of HNSC. Special attention is paid to calculate the magnetic excitations observed by inelastic neutron scattering (INS), their intensities, and their Q and temperature dependencies. This spectroscopic technique provides direct access to the energies and wave functions of the different spin states of the cluster; thus, it can be applied to spin clusters in order to obtain deep and detailed information on the nature of the magnetic exchange phenomenon. The general expression for the INS cross-section of spin clusters interacting by all kinds of exchange interactions, including also the single-ion zero-field splitting term, is derived for the first time. A closed-form expression is also derived for the particular case in which only the isotropic exchange interactions are involved. Finally this approach has been used to model the magnetic properties as well as the INS spectra of the polyoxometalate anion [Ni(9)(OH)(3)(H(2)O)(6)(HPO(4))(2)(PW(9)O(34))(3)](16)(-), which contains a central magnetic cluster formed by nine exchange-coupled Ni(II) ions surrounded by diamagnetic phosphotungstate ligands (PW(9)O(34))(9)(-).

17.
J Mal Vasc ; 18(2): 149-51, 1993.
Artigo em Francês | MEDLINE | ID: mdl-8350017

RESUMO

After a pelvic trauma, in a 78 years old women, systematic radiograms showed a polycyclic mass in the left side of the pelvis. This finding was confirmed by B-mode ultrasound echography. The vaginal touch found a pulsatile and expanding mass. At surgery, the diagnosis of a fissuring aneurysm of the internal iliac artery was confirmed, and a curative treatment was undertaken. Reviewing the literature, the authors emphasize the diagnostic usefulness of rectal and vaginal touch, and the importance of an early diagnosis using noninvasive imaging techniques. Surgery is the only treatment for isolated internal iliac aneurysms.


Assuntos
Dissecção Aórtica/diagnóstico , Aneurisma Ilíaco/diagnóstico , Pelve/lesões , Exame Físico/métodos , Idoso , Dissecção Aórtica/diagnóstico por imagem , Feminino , Humanos , Aneurisma Ilíaco/diagnóstico por imagem , Pelve/diagnóstico por imagem , Radiografia , Vagina
18.
Acta Otorrinolaringol Esp ; 49(5): 369-72, 1998.
Artigo em Espanhol | MEDLINE | ID: mdl-9717325

RESUMO

The value of immunotherapy (IT) in allergic rhinitis is debated. The results of a retrospective study of 67 patients treated with IT from 1985 to the end of 1995 are reported. Patients were classified as cured, improved, or not improved. Variables such as age, number and type of allergens, improvement, release, duration of evolution, and initial and final IgE levels were analyzed. Response to IT was favorable in 81.1% of cases. Improvement and cure were age-dependent, with the cure rate being significantly higher in patients over 30.


Assuntos
Dessensibilização Imunológica , Rinite Alérgica Perene/terapia , Rinite Alérgica Sazonal/terapia , Adolescente , Adulto , Fatores Etários , Idoso , Alérgenos/imunologia , Alérgenos/uso terapêutico , Criança , Estudos de Avaliação como Assunto , Feminino , Humanos , Imunoglobulina E/sangue , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Rinite Alérgica Perene/epidemiologia , Rinite Alérgica Perene/imunologia , Rinite Alérgica Sazonal/epidemiologia , Rinite Alérgica Sazonal/imunologia , Estações do Ano , Espanha/epidemiologia , Resultado do Tratamento
19.
Curr Med Res Opin ; 30(1): 19-26, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24083660

RESUMO

OBJECTIVES: The aim of this study was to ascertain the factors associated with non-achievement of triglyceride (TG) goals in a cohort of hypertriglyceridemic patients attending the lipid clinics of the Spanish Arteriosclerosis Society (LC-SAS). METHODS: Patients with high TG levels (>2.2 mmol/L; 200 mg/dL) were included in this multicenter, prospective, observational study and followed up for 1 year. The TG goal was ≤2.2 mmol/L (200 mg/dL). Main limitations of this study are that etiologic diagnosis of hypertriglyceridemia was not done under unified criteria and drug compliance was not evaluated. RESULTS: From 1394 patients initially included in the study, 929 (age range: 50 ± 12 years, 26% women) were followed up for 1 year; 523 patients (56%) failed to reach the TG target. These patients were younger, had a higher body mass index (BMI), were more frequently smokers, hypertensive and diabetic and had more severe dyslipidemia. They were also more sedentary, their diet was of poorer quality and they had higher alcohol consumption. The independent predictors of treatment failure were hypertriglyceridemia severity, low high density lipoprotein cholesterol (HDL-C), and high non-HDL-C, alcohol consumption and a raised BMI, while drug treatment had no predictive power. CONCLUSION: Independent predictors of failure to achieve hypertriglyceridemia treatment goals are inappropriate lifestyle, evidenced by insufficient weight loss, alcohol consumption and dyslipidemia severity.


Assuntos
Inibidores de Hidroximetilglutaril-CoA Redutases/uso terapêutico , Hipertrigliceridemia/tratamento farmacológico , Triglicerídeos/sangue , Consumo de Bebidas Alcoólicas , Glicemia , Índice de Massa Corporal , HDL-Colesterol/sangue , LDL-Colesterol/sangue , Feminino , Humanos , Estilo de Vida , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Fatores de Risco , Resultado do Tratamento
20.
Nephrologie ; 15(2): 137-40, 1994.
Artigo em Francês | MEDLINE | ID: mdl-8047199

RESUMO

Serious complications may occur after "blind" profound venous puncture in intensive care units. To secure these punctures, we designed a new fingertip pulsed Doppler (FPD) 5 MHz probe with a lateral to center indentation to guide the needle into the ultrasonic flux. A specific ultrasound analyzer indicating depth and diameter of the vessel was made for this use. The material was first tested in an experimental animal study. Results of animal venous punctures were successful 20/21. This material was then tested on patients with previous failure of "blind" punctures: results of 4 FPD punctures were successful in all 12 cases but one (catheterization not completed). We started a prospective multi-unit randomized study with various operators (junior residents, senior staff members), compared the success rate and type, the procedure duration of blind standard versus FPD punctures. We conclude in the safety and easy use of the FPD for central venous punctures.


Assuntos
Cateterismo Venoso Central , Cateteres de Demora , Veia Femoral/diagnóstico por imagem , Veias Jugulares/diagnóstico por imagem , Punções , Veia Subclávia/diagnóstico por imagem , Transdutores , Animais , Cuidados Críticos , Desenho de Equipamento , Feminino , Humanos , Masculino , Estudos Prospectivos , Coelhos , Diálise Renal , Segurança , Ultrassonografia , Veias Cavas/diagnóstico por imagem
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