RESUMO
Las aves y mamíferos constituyen la principal fuente de proteína animal para las poblaciones humanas originarias de la selva amazónica. La carne es destinada a la alimentación y otras partes del cuerpo son utilizadas en artesanías, adornos y objetos de uso cotidiano. Considerando el aprovechamiento y uso de la fauna, los objetivos del estudio fueron a) identificar las especies de aves y mamíferos aprovechadas por las poblaciones locales, b) determinar el uso de las aves y mamíferos, y c) calcular el valor económico de la biomasa extraída. Se realizó el registro del aprovechamiento de especies, mediante encuestas y la información recopilada fue sistematizada. Como resultado se encontró que en el Bajo Urubamba se aprovechan 10 especies de aves y 12 de mamíferos. El paujil (Mitu tuberosum) y las perdices (Crypturellus sp. y Tinamus tao) son las aves más aprovechadas. Se identificaron al majáz (Cuniculus paca), venado rojo (Mazama americana) y tapir o sachavaca (Tapirus terrestris) como los mamíferos con mayor biomasa extraída. El principal uso de la diversidad capturada es la alimentación de subsistencia.
Birds and mammals are the most important resource of protein for original groups of the amazon rainforest. Most of the meat is used for food and other parts of the animals are designates for the production of handicrafts, ornaments and other daily objects. Considering the use and exploitation of the fauna, the objectives of this study were: a) to identify the species of birds and mammals used by the local population; b) to determine what the uses of this animal are, and c) to calculate the economic value of the biomass extracted. We registered the exploitation and use of the species through surveys between the families. All the information was recorded, analyzed and systematized. We found that in the Lower Urubamba River, local families use 10 species of birds and 12 species of mammals. Paujil (Mitu tuberosum), Tinammus (Crypturellus sp. and Tinamus tao) are the species more commonly used. The lowland pacca (Cuniculus paca), Red brocket deer (Mazama americana) and tapir (Tapirus terrestris) are the mammals with the more extracted biomass. The most important use of these animals is for food (as meat) for subsistence of the families.
RESUMO
RESUMEN Objetivo Describir el proceso de construcción de la herramienta denominada Valoración Ocupacional de las personas con discapacidad en Colombia. Método Estudiomultimétodos, constituido por cinco fases, acompañadas por una estrategia transversal acompañada de diversos actores. La primera fase se basó en revisión documental, la segunda en juicio de expertos, La tercera permitió la evaluación de la herramienta por pares. La cuarta fase consistió en una prueba piloto, y la quinta fase se dedicó a la socialización de las herramientas con los actores participantes, para conocer sus sugerencias para el ajuste final. Resultados Se construyó una herramienta para valorar ocupacionalmente a personas con discapacidad en Colombia, basada en el enfoque de las capacidades humanas y el funcionamiento y de competencias laborales generales para favorecer la inclusión laboral. Conclusiones Se cuenta con una herramienta que promueva la inclusión laborar de las personas con discapacidad, respondiendo a lo contemplado en la Ley 1346 de 2009, Ley 1618 de 2013 y lo planteado en la Convención Internacional de los Derechos de las Personas con discapacidad. No reemplaza a las herramientas existentes, pero si promueve una percepción más favorable de las personas con discapacidad, facilitando su inclusión laboral.
ABSTRACT Objective Describing how a tool was designed for assessing disabled people in Colombia (called "Occupational evaluation of handicapped people in Colombia"). Method This was a multi-method studywhich consisted of five phases and a stakeholder participation-based strategy. The first stage of the multi-method research involved a literature review followed by expert judgment and then peer assessment of the tool; the fourth stage involved a pilot study and and a basic training course in occupational assessment involved the tool's socialisation with actors working in the field of occupational assessment, taking their suggestions into account for final adjustment of the tool. Results A tool was developed for the occupational assessment of disabled people in Colombia which was based on identifying their capabilities in terms of performance and general work skills to promote their inclusion in the workforce. Conclusions Considering the Colombian state's responsibility for ensuring disabled people's right to work and their inclusion in the workforce (Law 1346/2009, Law 1618/2013 and Convention on the Rights of People with Disabilities (CRPD)), this tool will not replace existing ones but will promote a more favourable perception of disabled people, thereby facilitating their inclusion in the workforce.
Assuntos
Humanos , Pessoas com Deficiência , Avaliação da Capacidade de Trabalho , Colômbia , Estudos Transversais , Projetos PilotoRESUMO
Objetivo Describir el proceso de construcción de una herramienta para la certificación de la condición de discapacidad en Colombia Método Se realiz- un estudio descriptivo, que por medio de una estrategia multimétodo busc- identificar desde diferentes perspectivas y con una metodologa participativa las necesidades, antecedentes, referentes, categorías, y procedimientos propicios para identificar y certificar la condición de discapacidad en un ciudadano colombiano. Resultados Una herramienta con la que el Sistema de Salud Colombiano y los profesionales del área de la salud pueden certificar la condición de discapacidad. Conclusiones La construcción de una herramienta que a través de la evaluación y certificación de la condición de discapacidad busca identificar a las personas con discapacidad como titulares de los derechos establecidos en la Ley, facilitando su acceso en condiciones de equidad, es una clara evidencia del compromiso del Estado Colombiano, de avanzar hacia una sociedad incluyente.
Objective Describing how a tool was created/constructed for certifying Colombian people's disability status. Method This was a descriptive study involving a five-phase, multi-method design. It sought to identify needs, background, categories and procedures from differingview points, using participatory methodology, for identifying and certifying disabled people in Colombia. Results The study led to an international classification of functioning, disability and health (ICF)-based certification tool which can be used by a multi-professional team in healthcare institution settings to guarantee access to benefits approved by Colombian disability law. Conclusions Certification (even when voluntary) can be the key to enjoying all the benefits designed for Colombian people suffering disability; such people are not the subjects of mercy and compassion anymore. Certification seeks to identify people suffering disabilities as holders of rights under Colombian law, as clear evidence of Colombian state commitment to ensuring an inclusive society.
Assuntos
Humanos , Avaliação da Deficiência , Pessoas com Deficiência , Registros , ColômbiaRESUMO
OBJECTIVE: Describing how a tool was created/constructed for certifying Colombian people's disability status. METHOD: This was a descriptive study involving a five-phase, multi-method design. It sought to identify needs, background, categories and procedures from differing view points, using participatory methodology, for identifying and certifying disabled people in Colombia. RESULTS: The study led to an international classification of functioning, disability and health (ICF)-based certification tool which can be used by a multi-professional team in healthcare institution settings to guarantee access to benefits approved by Colombian disability law. CONCLUSIONS: Certification (even when voluntary) can be the key to enjoying all the benefits designed for Colombian people suffering disability; such people are not the subjects of mercy and compassion anymore. Certification seeks to identify people suffering disabilities as holders of rights under Colombian law, as clear evidence of Colombian state commitment to ensuring an inclusive society.
Assuntos
Avaliação da Deficiência , Pessoas com Deficiência , Registros , Colômbia , HumanosRESUMO
OBJECTIVE: Describing how a tool was designed for assessing disabled people in Colombia (called "Occupational evaluation of handicapped people in Colombia"). METHOD: This was a multi-method study which consisted of five phases and a stakeholder participation-based strategy. The first stage of the multi-method research involved a literature review followed by expert judgment and then peer assessment of the tool; the fourth stage involved a pilot study and and a basic training course in occupational assessment involved the tool's socialisation with actors working in the field of occupational assessment, taking their suggestions into account for final adjustment of the tool. RESULTS: A tool was developed for the occupational assessment of disabled people in Colombia which was based on identifying their capabilities in terms of performance and general work skills to promote their inclusion in the workforce. CONCLUSIONS: Considering the Colombian state's responsibility for ensuring disabled people's right to work and their inclusion in the workforce (Law 1346/2009, Law 1618/2013 and Convention on the Rights of People with Disabilities (CRPD)), this tool will not replace existing ones but will promote a more favourable perception of disabled people, thereby facilitating their inclusion in the workforce.
Assuntos
Pessoas com Deficiência , Avaliação da Capacidade de Trabalho , Colômbia , Estudos Transversais , Humanos , Projetos PilotoRESUMO
This study investigated concentration and types of airborne fungi spores of indoor air. Forty nine houses of Santa Fe city (Argentina) were examined during one year. This city is characterized by a warm climate with an annual mean temperature of 18.6 degrees C and a relative humidity of 74.6%. Based on similar characteristics, a group of representative houses were selected from both urban and suburban areas. The study began by evaluating the airborne fungal concentrations on environmental factors such as area (urban-suburban), season (winter-summer) and presence/absence of a convection gas-fired heating system during winter. Samples were taken with a Standard RCS centrifugal air sampler which operates on the principle of impact onto an agar media strip by centrifugal force. Strips were filled with malt extract agar containing chloramphenicol to inhibit bacterial growth. After incubation and identification, concentrations of airborne fungi were calculated as CFU/m(3). Indoor results showed the presence of thirteen dominant genera: Cladosporium (58.90%), Alternaria (8.68%), Epicoccum (5.74%), Fusarium (5.37%), Curvularia (3.50%), Acremonium (1.27%), Drechslera (1.26%), Penicillium (1.25%), Aspergillus (1.14%), Mucor (0.61%), Ulocladium (0.57%), Nigrospora (0.48%), Chrysosporium (0.42%) and yeast (3.74%), whose presence varied throughout the year. Multivariate Analyses of Variance were performed to study the influence of environmental factors on concentrations of fungal flora. The results obtained were significant for season (lambda=0.1225), area (lambda=0.6371) and for the presence of a convection gas-fired heating system during winter (lambda=0.4765). ANOVA test for the season showed the highest fungal levels (Geometric Mean) in the summer for Alternaria (181.97 CFU/m(3) vs. 17.38 CFU/m(3)), Fusarium (158.49 CFU/m(3) vs. 2.14 CFU/m(3)), Curvularia (66.07 CFU/m(3) vs. 1.62 CFU/m(3)), Acremonium (7.24 CFU/m(3) vs. 2.29 CFU/m(3)), Mucor (3.16 CFU/m(3) vs. 1.15 CFU/m(3)), Nigrospora (2.34 CFU/m(3) vs. 1.07 CFU/m(3)), Chrysosporium (2.73 CFU/m(3) vs. 1.23 CFU/m(3)). In winter, the highest levels (Geometric Mean) were for Penicillium (5.13 CFU/m(3) vs. 1.91 CFU/m(3)) and yeast (16.22 CFU/m(3) vs. 3.09 CFU/m(3)). As for the area, ANOVA showed the highest fungal levels (Geometric Mean) in suburban areas for Cladosporium (676.08 CFU/m(3) vs. 380.19 CFU/m(3)), Curvularia (6.76 CFU/m(3) vs. 4.27 CFU/m(3)) Ulocladium (3.31 CFU/m(3) vs. 1.20 CFU/m(3)) and yeast (18.62 CFU/m(3) vs. 4.90 CFU/m(3)), while Aspergillus (4.57 CFU/m(3) vs. 1.38 CFU/m(3)), showed the highest levels (Geometric Mean) in the urban area. On the other hand, only Cladosporium showed a higher level (Geometric Mean) in houses without convection gas-fired heating system during winter, compared to that corresponding to heated houses.
Assuntos
Poluentes Atmosféricos/isolamento & purificação , Poluição do Ar em Ambientes Fechados/análise , Fungos/isolamento & purificação , Microbiologia do Ar , Poluentes Atmosféricos/classificação , Argentina , Cidades , Contagem de Colônia Microbiana , Monitoramento Ambiental , Fungos/classificação , Calefação , Habitação , Estações do AnoRESUMO
Malignant Peritoneal Mesothelioma (MPM) is an uncommon tumour. Clinical presentation is indefinite and differential diagnosis with peritoneal carcinomatosis is difficult. It has a bad prognosis (survival of 6-12 months) due to the delay of the diagnosis and inefficacy of the conventional therapeutic. The authors present a case of MPM which was diagnosed over the investigation of ascitis. The laparoscopic peritoneal biopsy permitted the diagnosis. After systemic quimiotherapy, the patient is in partial remission at 42 months of follow-up.
Assuntos
Mesotelioma , Neoplasias Peritoneais , Idoso , Humanos , Masculino , Mesotelioma/diagnóstico , Mesotelioma/terapia , Neoplasias Peritoneais/diagnóstico , Neoplasias Peritoneais/terapiaRESUMO
The (31)P MAS NMR spectrum of solid Li(3)P(7)(monoglyme)(3) has been reinvestigated over a wide temperature range (-70 to +77 degrees C) and under conditions of better resolution (Larmor frequency of 162 MHz and spinning rate of approximately 30 kHz) than previously measured (121 MHz and 13 kHz). At low temperatures three spinning sideband (ssb) manifolds are observed: a singlet (centered at -45 ppm relative to 85% H(3)PO(4)) due to the apical atom (A) of the P(7)-cage trianion; a 1 : 1 : 1 triplet (at -110, -117, and -124.5 ppm) due to the negatively charged equatorial (E) atoms, and a one to two doublet (at -161 and -168.5 ppm) due to the basal (B) atoms. These results are consistent with the P(7) cage having nearly, but not perfect, C(3v) symmetry. The compound appears to be well ordered in the solid state with very little structural dispersity. On heating, the NMR lines broaden and eventually coalesce into a single ssb manifold. This behavior is ascribed to bond-shift rearrangement similar to the Cope rearrangement in bullvalene. A MAS 2D exchange experiment and a quantitative analysis of the 1D NMR lineshapes indicate that, unlike in solution where the rearrangement involves a single bond shift at a time, in the solid the process involves a succession of two bond shifts: The first leads to an intermediate species in which the rearranged P(7) cage is inverted, while in the subsequent step a second bond shift takes place that also restores the original orientation of the cage in the lattice. The overall effect of the double bond shift is equivalent to cyclic permutation of the phosphorus atoms within the five member rings of the P(7)-cage. The quantitative analysis of the dynamic lineshapes shows that this cyclic permutation proceeds at a different rate in one ring (k(d)(1)) than in the other two (k(d)(2,3)). The kinetic parameters for these processes are E(a)(1)=18.7 kJ/mol, E(a)(2,3)=58.0 kJ/mol, k(d)(1)(17 degrees C)=k(d)(2,3)(17 degrees C)=10(4) s(-1). No indications for independent threefold molecular jumps of the P(7) cage were found.
RESUMO
During the period from 1994 to 1999 cutaneous leishmaniasis was reported in 32 (89%) out of 36 municipalities in the Metropolitan Region of Belo Horizonte, Brazil, of which one (2,8%) municipality was classified as a very high risk area, 16 (44,5%) as high risk, seven (19,4%) as moderate risk areas and 12 (33,3%) as low risk. From 1994 to 1995, visceral leishmaniasis was reported in six (16%) municipalities whereas in 1998 - 1999 this number increased to 15 (42%). Annual numbers of cases during 1994 to 1999 were 30, 53, 64, 53 and 84, respectively. In 19 (61.3%) municipalities no reference center for the diagnosis of the infection was available, so that most of the patients (80%) were referred to Belo Horizonte. Twelve (39%) municipalities have a center for leishmaniasis evaluation, however in only eight (67%) of these basic specific diagnostic tests were available. Rapid and extensive increase of leishmaniasis associated with low diagnosis capacity has been observed in the metropolitan area of Belo Horizonte.
Assuntos
Leishmaniose/diagnóstico , Leishmaniose/epidemiologia , Brasil , Humanos , Incidência , Fatores de Risco , População UrbanaRESUMO
During the period from 1994 to 1999 cutaneous leishmaniasis was reported in 32 (89%) out of 36 municipalities in the Metropolitan Region of Belo Horizonte, Brazil, of which one (2,8%) municipality was classified as a very high risk area, 16 (44,5%) as high risk, seven (19,4%) as moderate risk areas and 12 (33,3%) as low risk. From 1994 to 1995, visceral leishmaniasis was reported in six (16%) municipalities whereas in 1998 - 1999 this number increased to 15 (42%). Annual numbers of cases during 1994 to 1999 were 30, 53, 64, 53 and 84, respectively. In 19 (61.3%) municipalities no reference center for the diagnosis of the infection was available, so that most of the patients (80%) were referred to Belo Horizonte. Twelve (39%) municipalities have a center for leishmaniasis evaluation, however in only eight (67%) of these basic specific diagnostic tests were available. Rapid and extensive increase of leishmaniasis associated with low diagnosis capacity has been observed in the metropolitan area of Belo Horizonte.
No período de 1994 a 1999, foram notificados casos de leishmaniose tegumentar em 32 (89%) dos 36 municípios da Região Metropolitana de Belo Horizonte. Em um (2,8%) município o risco de adquirir a doença foi considerado muito alto, em 16 (44.5%), médio em sete (19,4%) e baixo em 12 (33.3%). Leishmaniose visceral foi notificada em seis (17%) dos 36 municípios, nos anos 94 e 95, elevando-se para 15 (42%) no biênio 98/99. O total de casos de leishmaniose visceral notificados anualmente no período 94 a 99 foi 30, 53, 64, 60, 53, 84, respectivamente. Não há serviços referenciados para atendimento da doença em 19 (61,3%) de 31 municípios, sendo 80% dos pacientes encaminhados para Belo Horizonte. Em 12 (39%) municípios com serviços referenciados, somente oito (67%) dispõem de testes diagnósticos específicos para leishmaniose. Verificou-se rápida e extensa expansão das leishmanioses na região metropolitana de Belo Horizonte e baixa capacidade de resolução diagnóstica pelos seus municípios.
Assuntos
Humanos , Leishmaniose/diagnóstico , Leishmaniose/epidemiologia , Brasil , Incidência , Fatores de Risco , População UrbanaRESUMO
The tr-ODESSA method (Reichert et al., J. Magn. Reson. 125, 245 (1997)), which is a 1D MAS experiment designed to monitor spin exchange involving both equivalent and inequivalent sites, is extended to situations where the spectrum consists of several spinning side band (ssb) manifolds with small chemical shift anisotropies. To increase the spectral resolution in such situations, the tr-ODESSA sequence is combined with that of PASS to a single experiment, which we term PATROS. In this hybrid experiment, magnetization transfer is monitored by the tr-ODESSA part, while the increase in resolution is provided by the separation of the ssb according to their order, during the PASS part. We demonstrate the feasibility of the method on a standard solid dimethylsulfone (DMS) sample and then apply it to monitor separately the ultraslow motions of the main- and side-chains in the polymer poly(n-butylmethacrylate). Theoretical expressions for the ssb intensities in PATROS experiments are derived and the merits and limitations of the method are discussed. Copyright 2000 Academic Press.
RESUMO
A major problem in dynamic 1D (13)C MAS NMR concerns the exchange between magnetically inequivalent, but chemically equivalent sites, whose signals are not resolved in the regular 1D spectrum. This difficulty may be overcome by properly preparing the initial nonequilibrium state of the spin system in the exchange experiments. In the present paper we discuss the advantages and limitations of several such experiments already in use and propose a new sequence, which we term SELDOM-ODESSA. Unlike the other 1D-exchange methods, this experiment yields pure absorption spectra that can more readily be analyzed quantitatively. The experiment is a hybrid comprising a SELDOM sequence, for selective excitation of one of the spinning sideband manifolds in the spectrum, followed by the ODESSA sequence, which induces alternate polarization in the excited sideband manifold. The evolution of the spectrum following this sequence provides information on both the exchange between congruent sites belonging to the same group of equivalent nuclei, and the exchange between inequivalent sites. Results are presented for a tropolone sample specifically enriched in carbon-13 at the carbonyl and hydroxyl sites. The dominant exchange mechanism in this sample involves spin diffusion. The various spin exchange processes in this sample, in the presence and absence of proton decoupling during the mixing time, are measured and discussed. Copyright 2000 Academic Press.
RESUMO
We recently evaluated the in vitro proliferative response and interferon (IFN)-gamma production of peripheral blood mononuclear cells from a group of 25 people who were treated for Chagas' disease during the acute phase of Trypanosoma cruzi infection and followed up for a period of 14-30 years. On the basis of the parasitological and serological tests, the individuals were classified as cured (C), dissociated, or not cured (NC). Members of group C (the group without cardiac alterations) presented significantly stronger proliferative response against the parasite antigens, with secretion of high levels of IFN-gamma in comparison with the NC group, raising a question about the role of this cytokine in the curing of human T. cruzi infection. Severe cardiac alterations were observed only in 1 of 25 patients, which suggests that treatment benefited the patients.
Assuntos
Doença de Chagas/tratamento farmacológico , Doença de Chagas/imunologia , Doença Aguda , Adolescente , Adulto , Idoso , Doença de Chagas/complicações , Doença Crônica , Seguimentos , Humanos , Interferon gama/análise , Ativação Linfocitária , Pessoa de Meia-IdadeRESUMO
Carbon-13 dynamic MAS NMR is used to determine the pi-flip rates of the phenyl rings in the low-molecular-weight members of the polyaryl ethers series (phenyl-O(-phenylene-O)n-phenyl). The first member in the series (diphenyl ether, n = 0) does not undergo measurable dynamic processes up to its melting point (28 degrees C). The second and third members (n = 1 and 2) exhibit, above room temperature, line broadening effects due to fast pi-flips of the terminal rings, while the spectra of the n = 1 homologue also exhibit line broadening for the inner phenylene ring. Kinetic parameters for the various pi-flip processes were derived by a detailed lineshape analysis of the MAS spectra. The measurements were extended to lower temperatures by time-reverse ODESSA experiments. The kinetic parameters derived from these experiments are, k(t)(300 K) = 31 s(-1), E(t) = 84 kJ/mol, and k(i)(300 K) = 1.3 s(-1), Ei = 77 kJ/mol for the n = 1 homologue and k(t)(300 K) = 3.2 s(-1), E(i) = 78 kJ/mol, for the n = 2 homologue, where the subscripts t and i refer to the terminal and inner benzene rings, respectively. For the simulation of the dynamic MAS spectra the Floquet expansion method was used. In an introductory chapter the Floquet method is reviewed with emphasis on the practical aspects of the computation procedure, on the sensitivity of the results to the isotropic and anisotropic chemical shift parameters, and on the form of the results in the limiting fast and slow exchange regimes.
Assuntos
Isótopos de Carbono , Espectroscopia de Ressonância Magnética , Éteres Fenílicos/químicaRESUMO
An apparently paradoxical role for IFN-gamma in human Chagas' disease was observed when studying the pattern of cytokine production by peripheral blood mononuclear cells (PBMC) obtained from two groups of chagasic patients after specific stimulation with Trypanosoma cruzi-derived antigens. The groups studied were 1) patients treated with benznidazole during the acute phase of Trypanosoma cruzi infection and 2) chronically infected untreated patients. In the treated group, higher levels of IFN-gamma were produced by PBMC from individuals cured after treatment when compared to non-cured patients. In contrast, in the chronically infected group (not treated) higher levels of IFN-gamma were produced by PBMC from cardiac patients in comparison with asymptomatic (indeterminate) patients. This apparently paradoxical role for IFN-gamma in human Chagas' disease is discussed in terms of the possibility of a temporal difference in IFN-gamma production during the initial stages of the infection (acute phase) in the presence or absence of chemotherapy. The maintenance of an immune response with high levels of IFN-gamma production during the chronic phase of the infection may favor cure or influence the development of the cardiac form of the disease.
Assuntos
Doença de Chagas/imunologia , Interferon gama/fisiologia , Doença de Chagas/sangue , Humanos , Leucócitos MononuclearesRESUMO
An apparently paradoxical role for IFN-gamma in human Chagas'disease was observed when studying the pattern of cytokine production by peripheral blood mononuclear cells (PBMC) obtained from two groups of chagasic patients after specific stimulation with Trypanosoma cruzi-derived antigens. The groups studied were 1) patients treated with bendnidazole during the acute phase of Trypanosoma cruzi infection and 2) chronically infected untreated patients. In the treated group, higher levels of IFN-gamma were produced by PBMC from individuals cured after treatment when compared to non-cured patients. In contrast, in the chronically infected group (not treated) higher levels of IFN-gamma were produced by PBMC from cardiac patients in comparison with asymptomatic (indeterminate) patients. This apparently paradoxical role for IFN-gamma in human Chagas'disease is discussed in terms of the possibility of a temporal difference in IFN-gamma production during the initial stages of the infection (acute phase) in the presence or absence of chemotherapy. The maintenance of an immune response with high levels of IFN-gamma production during the chronic phase of the infection may favor cure or influence the development of the cardiac form of the disease.
Assuntos
Humanos , Doença de Chagas/imunologia , Doença de Chagas/fisiopatologia , Interferon gama/fisiologia , Doença de Chagas/sangue , Leucócitos MononuclearesRESUMO
One- (1-D) and two-dimensional (2-D) carbon-13 NMR exchange measurements in powder samples of isotopically normal durene under magic angle spinning (MAS) are reported. The experiments include rotor synchronized 2-D exchange (RS2DE), 1-D magnetization transfer (MT) and time reverse ODESSA (tr-ODESSA). The latter two experiments were performed as a function of several external parameters, including proton decoupling field during mixing time, sample spinning rate and partly, of temperature. The effects of these parameters on the spin exchange induced by spin diffusion and by chemical, or physical exchange, is discussed. Spin exchange between all types of carbons in the durene molecules occurs on the time scale of seconds. From the dependence of the spin exchange rate on the external parameters it is concluded that the process is dominated by spin diffusion. On the basis of these results an upper limit of 10(-16) cm2 s(-1) can be set for the self-diffusion constant in crystalline durene.
Assuntos
Derivados de Benzeno/química , Espectroscopia de Ressonância Magnética/métodos , Isótopos de Carbono , Estrutura MolecularRESUMO
The orientation and temperature dependences of the deuterium NMR spectrum and spin-lattice relaxation time of the hydroxyl deuterons in single crystals of tropolone-d 1 are reported. The results are interpreted in terms of a dynamic hydrogen disorder model in which the hydrogen nuclei move in an asymmetric double well potential. According to this model, the hydrogen-bonded dimer structure as determined by X-ray diffraction constitutes a majority species in the tropolone crystal, comprising more than 98% of the molecules at room temperature. However, there also exists a tautomeric minority species formed by a concerted back and forth shifting of the hydroxyl hydrogens (deuterons) along the hydrogen bonds to the nearby carbonyl oxygens. This process results in a modulation of the electric field gradient tensor at the site of the deuterons, thus providing an efficient relaxation mechanism. The concentration of the minority species is too low and its lifetime is too short to make its direct observation possible. Still, structural information about this species and kinetic and thermodynamic parameters of the hydrogen shift process can be derived by fitting the measured T 1 values to the above model.
RESUMO
The aim of this study is to evaluate the effects of parasite clearance on the immunological profile of peripheral blood mononuclear cells (PBMC) from chagasic patients submitted to specific drug therapy. PBMC were examined by flow cytometry and proliferative responsiveness to Trypanosoma cruzi-related stimuli. Three groups of patients were studied: not treated (NT), treated not cured (TNC) and cured (C). All data were compared to values from uninfected individuals (NI). NT displayed a lower percentage of CD3+ cells as compared to NI, while TNC and C had mean values that were between those from NI and NT. Infected patients had double the percent of CD3+ HLA-DR+ cells, independent of the efficacy of the treatment. Thus, absence of circulating parasites did not reduce T cell activation in Chagas' disease. NT displayed a higher percentage of CD5+ B cells as compared to NI, while TNC and C had mean values between those from NI and NT. In contrast to the phenotypic data, the in vitro mean proliferative responses to parasite-related stimuli of PBMC from C were reduced to the low mean levels observed in NI. These striking differences were statistically different from the high responses seen in NT and TNC. Our data suggest that proliferative responses of PBMC from C reflect immunological changes due elimination of parasite. However, successful treatment did not alter the levels of peripheral T cell activation.