Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 99
Filtrar
1.
Talanta ; 221: 121601, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-33076132

RESUMO

A simple, efficient matrix solid phase dispersive extraction (MSPD) method was optimised to analyse simultaneously polycyclic aromatic hydrocarbons (PAHs) and polychlorobiphenyls (PCBs) from sediments, and was compared to microwave-assisted extraction (MAE). New dispersing agents were tested to improve MSPD extraction. 3-chloropropyl-bonded silica particles, in addition to Florisil, increased significantly the polyaromatics desorption capacity. A compromise was found for eluting both families of compounds from sediments, using a small volume of hexane/acetone. Low procedural detection limits could be reached (0.06-0.22 ng g-1 and 0.3-1.1 ng g-1 for PAHs and PCBs, respectively). Mean total extraction recoveries were good for PAHs (>67%, depending on the sediment) and for PCBs (>89%), with good precision (6-9% and 4-10% inter-day precision for PAHs and PCBs, respectively). Higher recoveries for PCBs could be reached in comparison with formerly developed sonication or Soxhlet extraction methods, but also with MAE. MSPD offered significant decrease of sample amount, of solvent consumption and allowed more efficient cleaning of the sediment matrix, leading to less matrix effects compared to MAE, removing lots of interfering compounds without additional purification step. The robustness of the MSPD methodology could be demonstrated extracting quantitatively sediments from different sources and with various mineralogical characteristics.

2.
Chemosphere ; 228: 744-755, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31071561

RESUMO

Electrokinetic (EK) remediation is often developed for metal decontamination but shows limitations for polycyclic aromatic hydrocarbons (PAHs) and polychlorobiphenyls (PCBs) which are nonionic and involve low aqueous solubility. This paper reports many laboratory studies devoted to the investigations of EK efficiency on the mobility and the removal of metals, PAHs and PCBs from dredged sediments, using a mixture of chelating agent and surfactants. The results showed that increasing chelating agent concentration was favorable for both metal and PAH removal. Applying a periodic voltage gradient associated to a low concentration of additives provided the best removal of Zn, Cd and Pb and also the 16 priority PAHs. The tested fresh harbor sediment was highly resistant to metals and organics mobilization and transport because of an aged contamination, a high buffering capacity, a very low hydraulic permeability and a high organic matter content. However, experiments performed on a former sediment which was deposited many years ago provided better removal results, involving low organic matter and carbonates content. The efficiency of the EK process was also assessed by measuring the acute toxicity of the EK-treated sediment on the copepod Eurytemora affinis exposed to sediment elutriates.


Assuntos
Copépodes/efeitos dos fármacos , Recuperação e Remediação Ambiental/métodos , Sedimentos Geológicos/química , Poluentes Químicos da Água/toxicidade , Animais , Quelantes/química , Eletroquímica/métodos , França , Concentração de Íons de Hidrogênio , Metais/isolamento & purificação , Bifenilos Policlorados/isolamento & purificação , Hidrocarbonetos Policíclicos Aromáticos/isolamento & purificação , Tensoativos/química , Testes de Toxicidade Aguda , Poluentes Químicos da Água/química , Poluentes Químicos da Água/isolamento & purificação
3.
Phytopathology ; 109(4): 512-530, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30461350

RESUMO

The Fusarium oxysporum species complex includes both plant pathogenic and nonpathogenic strains, which are commonly found in soils. F. oxysporum has received considerable attention from plant pathologists for more than a century owing to its broad host range and the economic losses it causes. The narrow host specificity of pathogenic strains has led to the concept of formae speciales, each forma specialis grouping strains with the same host range. Initially restricted to one plant species, this host range was later found to be broader for many formae speciales. In addition, races were identified in some formae speciales, generally with cultivar-level specialization. In 1981, Armstrong and Armstrong listed 79 F. oxysporum formae speciales and mentioned races in 16 of them. Since then, the known host range of F. oxysporum has considerably increased, and many new formae speciales and races have been identified. We carried out a comprehensive search of the literature to propose this review of F. oxysporum formae speciales and races. We recorded 106 well-characterized formae speciales, together with 37 insufficiently documented ones, and updated knowledge on races and host ranges. We also recorded 58 plant species/genera susceptible to F. oxysporum but for which a forma specialis has not been characterized yet. This review raises issues regarding the nomenclature and the description of F. oxysporum formae speciales and races.


Assuntos
Fusarium , Especificidade de Hospedeiro , Fusarium/classificação , Fusarium/patogenicidade , Doenças das Plantas , Plantas
4.
Sci Total Environ ; 607-608: 944-953, 2017 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-28724226

RESUMO

Electrokinetic (EK) remediation can be a suitable technology for treating contaminated dredged harbor sediment, stored on terrestrial disposal sites. Citric acid (CA) and biosurfactants (rhamnolipids and saponin) were chosen as enhancing agents for simultaneous metal (Cd, Cr, Cu, Pb, Zn) and PAH/PCB removal by EK because of their potential low toxicity with a view to site restoration. Three EK runs were performed using a periodic voltage (1Vcm-1) and various concentrations of agents. The best combination of CA (0.2molL-1) and saponin (0.85gL-1) did not remove high amounts of metals (4.4-15.8%) and provided only slightly better results for PAH and PCB removal (29.2% and 38.2%, respectively). The harbor sediment was highly resistant to metal and organics mobilization and transport because of an aged contamination, a high buffering capacity, a very low hydraulic permeability and a high organic matter content. The efficiency of the EK process was also assessed by measuring the acute toxicity of the EK-treated sediment on E. affinis copepods exposed to sediment elutriates. Fortunately, the use of CA and biosurfactants did not significantly impact on sediment toxicity. Some treated sediment sections, particularly those near the anode compartment, were statistically more toxic than the raw sediment. More particularly, E. affinis copepods were significantly sensitive to low pH values and oxidative conditions, to Cu, and to a lesser extent to Pb amounts. The speciation of these metals probably changed in these pH and redox conditions so that they became more easily leachable and bioavailable. In contrast, toxicity was negatively correlated to PAH and PCB amounts after EK treatment, probably due to the production of oxidized metabolites of PAHs and PCBs.


Assuntos
Poluentes Ambientais/análise , Recuperação e Remediação Ambiental , Sedimentos Geológicos/análise , Metais Pesados/análise , Bifenilos Policlorados/análise , Hidrocarbonetos Policíclicos Aromáticos/análise , Animais , Bioensaio , Copépodes , Testes de Toxicidade Aguda
6.
Phys Chem Chem Phys ; 16(24): 12228-36, 2014 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-24818591

RESUMO

High-resolution single crystal X-ray diffraction is used for the first time to obtain the charge density distribution in dehydrated Na-X zeolite. The electron density is extracted according to the Hansen & Coppens multipolar-model, from which Pval-κ-type atomic charges are derived. In order to compare the experimental electron density with theoretical calculations on zeolites and other minerals, a topological analysis is performed to derive AIM charges and electron density properties at bond critical points. The results are compared with that described in the literature. Finally, the electrostatic potential is evaluated in a periodic, mean field approach (disordered cation distribution in the Fd3[combining macron] space group) and for a given distribution of the cations (space group P1). The electrostatic energy is, then, derived in the neighbourhood of cation sites where the molecules are usually physisorbed.

7.
J Pharm Biomed Anal ; 83: 194-201, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-23764657

RESUMO

The final step of an active pharmaceutical ingredient (API) manufacturing synthesis process consists of a crystallization during which the API and residual solvent contents have to be quantified precisely in order to reach a predefined seeding point. A feasibility study was conducted to demonstrate the suitability of on-line NIR spectroscopy to control this step in line with new version of the European Medicines Agency (EMA) guideline [1]. A quantitative method was developed at laboratory scale using statistical design of experiments (DOE) and multivariate data analysis such as principal component analysis (PCA) and partial least squares (PLS) regression. NIR models were built to quantify the API in the range of 9-12% (w/w) and to quantify the residual methanol in the range of 0-3% (w/w). To improve the predictive ability of the models, the development procedure encompassed: outliers elimination, optimum model rank definition, spectral range and spectral pre-treatment selection. Conventional criteria such as, number of PLS factors, R(2), root mean square errors of calibration, cross-validation and prediction (RMSEC, RMSECV, RMSEP) enabled the selection of three model candidates. These models were tested in the industrial pilot plant during three technical campaigns. Results of the most suitable models were evaluated against to the chromatographic reference methods. Maximum relative bias of 2.88% was obtained about API target content. Absolute bias of 0.01 and 0.02% (w/w) respectively were achieved at methanol content levels of 0.10 and 0.13% (w/w). The repeatability was assessed as sufficient for the on-line monitoring of the 2 analytes. The present feasibility study confirmed the possibility to use on-line NIR spectroscopy as a PAT tool to monitor in real-time both the API and the residual methanol contents, in order to control the seeding of an API crystallization at industrial scale. Furthermore, the successful scale-up of the method proved its capability to be implemented in the manufacturing plant with the launch of the new API process.


Assuntos
Cristalização/métodos , Indústria Farmacêutica/métodos , Preparações Farmacêuticas/química , Espectroscopia de Luz Próxima ao Infravermelho/métodos , Análise dos Mínimos Quadrados , Modelos Teóricos , Análise Multivariada , Análise de Componente Principal/métodos
8.
Pharmacoepidemiol Drug Saf ; 21(12): 1344-9, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23111820

RESUMO

UNLABELLED: Computerized hospital databases are used for clinical and economic research. In France, the hospital administrative database, Programme de médicalisation des systèmes d'information (PMSI), could be an interesting means for identifying cases of abuse and dependence in hospitals. PURPOSE: To assess the capability of PMSI to identify cases of abuse and dependence (medicines or illicit drugs; tobacco and alcohol not included). METHODS: Cross-sectional study, from October 1 to December 31, 2008, in teaching hospitals of Bordeaux. All hospitalizations with an ICD-10 code related to possible abuse or dependence were selected. Cases were validated by a committee composed of three pharmacologists using discharge summaries. RESULTS: Among the 34 816 patients registered in the PMSI during the study period, a total of 227 patients were pre-selected as potential cases; 21 patients, hospitalized for abuse or dependence, or complications of which, were included in the analysis. Mean age was 35 years. Substances implicated were buprenorphine (n = 8), benzodiazepines (n = 7), cannabis (n = 6), cocaine (n = 4), heroin (n = 3), amphetamine, ecstasy, morphine, codeine, and tramadol (n = 1, respectively); there was polydrug use in six cases. CONCLUSIONS: The PMSI database can be useful to identify certain cases of abuse and dependence. This pilot study has been conducted at a local level; as the PMSI is available in all hospital settings in France, further analysis could be done at the regional and national levels. Such data could be a valuable indicator to analyze trends and assess the medical consequences of substance abuse.


Assuntos
Sistemas Computadorizados de Registros Médicos , Transtornos Relacionados ao Uso de Substâncias/epidemiologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Pré-Escolar , Estudos Transversais , Feminino , França/epidemiologia , Hospitais , Humanos , Lactente , Recém-Nascido , Masculino , Pessoa de Meia-Idade
9.
Med Mal Infect ; 42(9): 440-3, 2012 Sep.
Artigo em Francês | MEDLINE | ID: mdl-22925551

RESUMO

INTRODUCTION: Ertapenem could be used to treat urinary tract infections (UTI) caused by ESBL producing enterobacteriacae (ESBL-E) and administered subcutaneously. METHOD: The authors made a retrospective study on adult patients treated with ertapenem administered intravenously or subcutaneously for UTI caused by ESBL-E, between May 2009 and August 2011 at the Chambery hospital, France. RESULTS: Twenty-five patients were treated (13 cases of prostatitis, ten of pyelonephritis, two of cystitis) mostly caused by Escherichia coli (24 cases). Subcutaneous injections were administered to 20 patients and 23 were treated through outpatient parenteral antibiotic therapy (OPAT). All patients were cured at the end of the ertapenem therapy. Urine samples collected during treatment for 12 patients were sterile. Three months after the end of the treatment, five patients had relapsed, and six had developed a UTI caused by another bacteria. CONCLUSION: Ertapenem administered intravenously or subcutaneously could be an effective treatment for UTI caused by ESBL-E, especially using OPAT.


Assuntos
Cistite/tratamento farmacológico , Infecções por Escherichia coli/tratamento farmacológico , Proteínas de Escherichia coli/análise , Escherichia coli/enzimologia , Prostatite/tratamento farmacológico , Pielonefrite/tratamento farmacológico , Resistência beta-Lactâmica , beta-Lactamases/análise , beta-Lactamas/uso terapêutico , Adulto , Idoso , Idoso de 80 Anos ou mais , Assistência Ambulatorial , Cistite/microbiologia , Avaliação de Medicamentos , Ertapenem , Escherichia coli/efeitos dos fármacos , Infecções por Escherichia coli/microbiologia , Feminino , Humanos , Injeções Intravenosas , Injeções Subcutâneas , Infecções por Klebsiella/tratamento farmacológico , Infecções por Klebsiella/microbiologia , Klebsiella pneumoniae/efeitos dos fármacos , Klebsiella pneumoniae/enzimologia , Klebsiella pneumoniae/isolamento & purificação , Masculino , Pessoa de Meia-Idade , Prostatite/microbiologia , Pielonefrite/microbiologia , Recidiva , Estudos Retrospectivos , Fatores de Risco , beta-Lactamas/administração & dosagem
11.
J Helminthol ; 85(3): 339-44, 2011 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-21062527

RESUMO

The tapeworm Ligula intestinalis commonly infests roach (Rutilus rutilus) and is responsible for the inhibition of gonad development. In order to better understand the effect of the plerocercoid on fish physiology, and to discriminate parasitization effects from those of endocrine-disrupting compounds (EDC), Cyp19b and Cyp19a aromatase expression was investigated by real-time quantitative polymerase chain reaction (PCR) in brain and gonads of ligulosed roach, caught from a reference site. Data were compared to reproductive and endocrine endpoints previously reported in a larger cohort study (including the sampled population of the present one), such as gonadosomatic index, Fulton index, gonadal histology, plasma sex steroid levels and brain aromatase activity. A decrease in Cyp19b expression in the brain of infected fish was demonstrated, in agreement with the reduction of aromatase activity previously described. In contrast, Cyp19a expression in the gonads appeared to be enhanced in ligulosed fish, in accordance with the presence of immature but differentiated sexual tissues. Together these results show that: (1) L. intestinalis infestation results in an alteration of aromatase expression which, in particular, may have profound effects on the fish brain; and (2) L. intestinalis infection must be considered as a major confounding factor in ecotoxicological studies using aromatase expression as an EDC biomarker. Moreover, the concordance between activity and expression--investigated for the first time in the same population--gives a functional relevance to the transcript aromatase dosage in the brain. Finally, quantitative PCR was confirmed as a sensitive approach, enabling aromatase status to be defined in the poorly developed gonads of ligulosed individuals.


Assuntos
Aromatase/biossíntese , Cestoides/isolamento & purificação , Cestoides/patogenicidade , Cyprinidae/parasitologia , Animais , Encéfalo/enzimologia , DNA de Helmintos/genética , Feminino , Gônadas/enzimologia , Masculino , Reação em Cadeia da Polimerase/métodos , Peixe-Zebra , Proteínas de Peixe-Zebra/biossíntese
13.
Ann Chir Plast Esthet ; 55(1): 78-81, 2010 Feb.
Artigo em Francês | MEDLINE | ID: mdl-19272689

RESUMO

The necrotizing fasciitis (NF) is a soft tissue infection affecting the superficial fascia, the subcutaneous tissue and the skin, the latter being affected tardively. This diagnosis is confirmed only after surgery, which consists of debridement of the necrotized tissue. The discordance between the symptomatology and physical exam made that the diagnosis is mistaken in 35% of cases. However, it seems important to remember that the prompt recognition and surgical treatment depend on the morbidity and mortality. We report the case of a patient with NF of the upper limb after a right elbow blunt trauma.


Assuntos
Fasciite Necrosante/etiologia , Transplante de Pele/métodos , Ferimentos não Penetrantes/complicações , Combinação Amoxicilina e Clavulanato de Potássio/uso terapêutico , Anti-Infecciosos/uso terapêutico , Fasciite Necrosante/microbiologia , Fasciite Necrosante/terapia , Feminino , Humanos , Pessoa de Meia-Idade , Infecções Estreptocócicas/complicações , Streptococcus pyogenes/isolamento & purificação
14.
Parasitology ; 137(4): 697-704, 2010 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-19961656

RESUMO

The effects of parasite infection by the cestode Ligula intestinalis on the reproductive function and endocrine system of wild roach Rutilus rutilus were evaluated. Gonad maturation, plasma vitellogenin, plasma steroid concentrations (i.e. progesterone, 11-keto-testosterone and 17-beta-estradiol) and brain aromatase activity were investigated in relation with parasitization. A low prevalence (8%) of ligulosed roach and a moderate impact of parasitization (mean parasitization index of 8.8%) were found in the studied population. Inhibition of gonad maturation generally resulted from infestation but 5% of the ligulosed roach nevertheless reached maturity. Main sex steroid plasma content was depleted in both genders. Male 11-keto-testosterone, female 17-beta-estradiol and progesterone plasma concentrations of both genders were, respectively, 27, 5 and 3 times lower in ligulosed fish when compared to their non-infected counterparts. Progesterone levels were negatively correlated with the parasitization index in females. Brain aromatase activity of infected roach was reduced to 50% of that of the non-infected fish. These results demonstrate significant negative effects on the reproductive function of wild roach infected by the tapeworm L. intestinalis collected from a site with low contamination.


Assuntos
Cestoides/fisiologia , Cyprinidae/parasitologia , Sistema Endócrino/parasitologia , Interações Hospedeiro-Parasita , Reprodução , Animais , Aromatase/metabolismo , Encéfalo/enzimologia , Cyprinidae/sangue , Cyprinidae/fisiologia , Feminino , Masculino , Densidade Demográfica , Esteroides/sangue , Vitelogeninas/sangue
15.
Inorg Chem ; 48(11): 4729-36, 2009 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-19374370

RESUMO

Two pseudo-octahedral iron(II) complexes, Fe(stpy)(4)(NCSe)(2), containing photoresponsive ligands (cis <--> trans isomerization of -CHCH-) were prepared with trans- or cis-styrylpyridine (stpy) isomers. The magnetic behavior of the polycrystalline solids was previously shown to depend on the configuration of the stpy ligand. The crystal X-ray structures were determined at 293 and 104 K for both isomers. The all-trans and all-cis compounds crystallize in the orthorhombic (Pna2(1)) and the monoclinic space groups (C2/c), respectively. No symmetry change occurs upon cooling to 104 K. The Fe(II) centers lie in axially compressed octahedra with NCSe anions in the apical position and the four pyridinic nitrogens in the meridional plane. The variation of metal-ligand bond lengths as a function of temperature reflects the thermal S = 0 <--> S = 2 crossover of all-trans complexes and the S = 2 ground state of all-cis complexes. The unit-cell volumes per metal ion also change accordingly, and the relative variation due to the spin-crossover compares those associated with the formal change of configuration of the four stpy isomers. The photomagnetic responses were investigated at 130 K with doped polymer thin films containing all-cis (high-spin) or all-trans species (partly low-spin). The 130 K illumination of these doped poly(methyl methacrylate) (PMMA) films leads to the UV-vis absorption features typical for the cis <--> trans photoisomerization of the stilbenoid moiety. The direct magnetic measurements have unambiguously established the photomagnetic effect named ligand-driven light-induced spin change (LD-LISC). The 355 nm excitation of doped thin films produces very long lifetime states that are manifested by high-spin to low-spin (all-cis complex) and low-spin to high-spin (all-trans complex) changes of the Fe(II) magnetic behavior; the process is bidirectional. A structural analysis based on the single-crystal X-ray diffraction data has been proposed to rationalize the LD-LISC activity detected here for doped PMMA thin films.

16.
Transplant Proc ; 39(8): 2578-9, 2007 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-17954180

RESUMO

All over the world, transplant teams are looking for ways to increase and improve the donor pool. Non-heart-beating donation may increase the number of donors, even if some technical, logistical, and emotional problems are still encountered. The results obtained by our team should stimulate other centers to implement this kind of donation in their hospitals. Herein we have described our experience with non-heart-beating donation.


Assuntos
Morte Súbita Cardíaca , Parada Cardíaca , Transplante das Ilhotas Pancreáticas/fisiologia , Transplante de Rim/fisiologia , Transplante de Fígado/fisiologia , Doadores de Tecidos/estatística & dados numéricos , Bélgica , Humanos , Estudos Retrospectivos , Resultado do Tratamento
17.
Ann Endocrinol (Paris) ; 68(1): 45-50, 2007 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-17316546

RESUMO

BACKGROUND: Polycystic ovary syndrome (PCOS) is a frequent cause of infertility. Despite an impressive number of reports, few have evaluated the influence of age upon fertility. We present the outcomes of three infertile women with PCOS who achieved spontaneous pregnancies when ageing. CASE REPORTS: Three patients with PCOS were monitored for more than 20 years. PCOS was confirmed by clinical data (oligo/amenorrhoea, infertility, hirsutism), hormonal measures and ovarian ultrasonography. All three infertile patients were treated for several years using numerous ovulation induction protocols with varying responses. When ageing, they gained more regular cycles and spontaneously became pregnant at 39, 40 1/2 and 36 years of age, more than 5 years after induction treatment was stopped, and in spite of increasing weight in each of them. CONCLUSIONS: These clinical observations suggest improved fertility in some PCOS ageing women. The positive impact of ageing on cycle regularisation in PCOS has recently been claimed but the fertility outcome was not evaluated. Ovary ageing results in diminution of the follicular cohort in both normal and PCOS women, associated with decreased inhibin B and anti-müllerian hormone (AMH) levels. Lower inhibin B levels induce FSH enhancement, with a rise in FSH rate per follicle which may determine better follicle maturation, regular and ovulatory cycles in PCOS ageing women. The best proof of this improved fertility was the occurrence of spontaneous pregnancies which never occurred previously.


Assuntos
Envelhecimento/fisiologia , Fertilidade/fisiologia , Síndrome do Ovário Policístico/fisiopatologia , Reprodução/fisiologia , Adulto , Amenorreia/etiologia , Feminino , Hormônio Foliculoestimulante/sangue , Seguimentos , Humanos , Infertilidade Feminina/etiologia , Hormônio Luteinizante/sangue , Pessoa de Meia-Idade , Síndrome do Ovário Policístico/sangue , Testosterona/sangue , Fatores de Tempo
18.
Bull Entomol Res ; 95(5): 393-9, 2005 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-16197559

RESUMO

The role of various olfactory and visual stimuli was studied in host-plant finding by the asparagus fly Plioreocepta poeciloptera (Schrank), a monophagous monovoltine tephritid causing serious damage to asparagus spears. Volatiles released by asparagus plants were extracted by diethyl ether after cryotrapping concentration, and identified by gas chromatography-mass spectrometry. Twelve of the 13 compounds identified were tested using electroantennography to measure the response of the fly. Behavioural response was analysed using two different flight tunnels according to circadian rhythm, age and sex of adults, presence of the plant and of different coloured lures, presence of a male congener, or exposure to four pure asparagus odour compounds that elicited responses in electroantennography, i.e. hexanal, (E)-2-hexenal, (Z)-2-hexen-1-ol and decanal. Data showed that males locate the host plant more quickly than females. Females are attracted mainly by the blend of plant odour and male pheromone. Both sexes respond to a complex of stimuli only during the afternoon. These findings will be helpful in developing new and effective approaches to control this pest insect.


Assuntos
Asparagus/fisiologia , Asparagus/parasitologia , Tephritidae/fisiologia , Animais , Asparagus/química , Comportamento Animal/fisiologia , Ritmo Circadiano , Feminino , Masculino , Odorantes , Controle Biológico de Vetores , Olfato/fisiologia , Visão Ocular/fisiologia
19.
Transplant Proc ; 37(6): 2821-2, 2005.
Artigo em Inglês | MEDLINE | ID: mdl-16182819

RESUMO

The shortage of donated organs has become a problem in transplantation throughout the world. Transplant teams are looking for other ways to increase and improve the donor pool. Non-heart-beating donation may be a source to increase the number of donors, even if some technical, logistical, and emotional problems are encountered. The results obtained by our team should stimulate other centers to implement this kind of donation in their hospitals. We describe our experience in the policy of non-heart-beating donation and encourage transplant centers to develop such a program.


Assuntos
Parada Cardíaca , Transplante de Órgãos/fisiologia , Doadores de Tecidos/estatística & dados numéricos , Bélgica , Morte Encefálica , Humanos , Transplante de Órgãos/métodos , Estudos Retrospectivos , Obtenção de Tecidos e Órgãos/métodos , Resultado do Tratamento
20.
J Phys Chem B ; 109(7): 2723-32, 2005 Feb 24.
Artigo em Inglês | MEDLINE | ID: mdl-16851280

RESUMO

High-resolution X-ray diffraction and polarized neutron diffraction experiments have been performed on the Y-semiquinonate complex, Y(HBPz3)2(DTBSQ), in order to determine the charge and spin densities in the paramagnetic ground state, S = (1/2). The aim of these combined studies is to bring new insights to the antiferromagnetic coupling mechanism between the semiquinonate radical and the rare earth ion in the isomorphous Gd(HBPz3)2(DTBSQ) complex. The experimental charge density at 106 K yields detailed information about the bonding between the Y3+ ion and the semiquinonate ligand; the topological charge of the yttrium atom indicates a transfer of about 1.5 electrons from the radical toward the Y3+ ion in the complex, in agreement with DFT calculations. The electron density deformation map reveals well-resolved oxygen lone pairs with one lobe polarized toward the yttrium atom. The determination of the induced spin density at 1.9 K under an applied magnetic field of 9.5 T permits the visualization of the delocalized magnetic orbital of the radical throughout the entire molecule. The spin is mainly distributed on the oxygen atoms [O1 (0.12(1) mu B), O2(0.11(1) mu B)] and the carbon atoms [C21 (0.24(1) mu B), C22(0.20(1) mu B), C24(0.16(1) mu B), C25(0.12(1) mu B)] of the carbonyl ring. A significant spin delocalization on the yttrium site of 0.08(2) mu B is observed, proving that a direct overlap with the radical magnetic orbital can occur at the rare earth site and lead to antiferromagnetic coupling. The DFT calculations are in good quantitative agreement with the experimental charge density results, but they underestimate the spin delocalization of the oxygen toward the yttrium and the carbon atoms of the carbonyl ring.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...