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1.
Plant Biol (Stuttg) ; 24(2): 292-301, 2022 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-34806266

RESUMEN

'Brejos de altitude' is an ecosystem that has been subjected to severe exploitation, leading to an intense reduction in Brazil. Understanding the patterns of bryophyte diversity and composition, particularly of specialized species such as the epiphylls, to anthropic and abiotic variables is crucial for implementing protection measures. We investigated the relationship between composition and diversity of epiphyllous bryophytes and anthropic (edge effects) and abiotic (altitude) variables at local (within each 'Brejo') and regional (set of three 'Brejos') scale. Abiotic and anthropic variables were correlated with alpha and beta diversity (decomposed into species replacement and richness differences) using GLM. Their effects on species composition were evaluated using PERMANOVA. The localities at higher elevations harboured a richer bryoflora and overall beta diversity patterns were associated with altitude and locality, which acted over different scales. Regionally, the contribution of richness differences was limited with increasing altitude. Yet, dissimilarities among localities were associated with richness differences and replacement, denoting the importance of local factors. The composition was explained by local factors interacting with the regional altitudinal gradient. Anthropic activity was significant only when interacting with local factors and altitudinal gradient. Environmental filtering associated with altitude played a more important role in shaping the diversity and composition of epiphyllous bryophytes, at both regional and local scales. Each 'Brejo' acts as an ecological refuge, harbouring part of the whole environmental gradient, and presents a unique floristic composition. Moreover, partitioning beta diversity highlighted the interplay of local and regional forces shaping diversity patterns.


Asunto(s)
Briófitas , Ecosistema , Altitud , Biodiversidad , Brasil
2.
J Neuroimmune Pharmacol ; 16(2): 390-402, 2021 06.
Artículo en Inglés | MEDLINE | ID: mdl-32564332

RESUMEN

Inflammation is a predominant aspect of neurodegenerative diseases and experimental studies performed in animal models of Parkinson's disease (PD) suggesting that a sustained neuroinflammation exacerbates the nigrostriatal degeneration pathway. The central role of microglia in neuroinflammation has been studied as a target for potential neuroprotective drugs for PD, for example nonsteroidal anti-inflammatory drugs (NSAIDs) and matrix metalloproteinases (MMP) inhibitors that regulates microglial activation and migration. The aim of this study was to investigate the neuroprotective response of the iminosugar 1-deoxynojirimycin (1-DNJ) and compare its effect with a combined treatment with ibuprofen. MPTP-treated mice were orally dosed with ibuprofen and/or 1-DNJ 1. Open-field test was used to evaluate behavioral changes. Immunohistochemistry for dopaminergic neurons marker (TH+) and microglia markers (Iba-1+; CD68+) were used to investigate neuronal integrity and microglial activation in the substantia nigra pars compacta (SNpc). The pro-inflammatory cytokines TNF-α and IL-6 were analysed by qPCR. Treatments with either 1-DNJ or Ibuprofen alone did not reduce the damage induced by MPTP intoxication. However, combined treatment with 1-DNJ and ibuprofen prevents loss of mesencephalic dopaminergic neurons, decreases the number of CD68+/ Iba-1+ cells, the microglia/neurons interactions, and the pro-inflammatory cytokines, and improves behavioral changes when compared with MPTP-treated animals. In conclusion, these data demonstrate that the combined treatment with a MMPs inhibitor (1-DNJ) plus an anti-inflammatory drug (ibuprofen) has neuroprotective effects open for future therapeutic interventions. Graphical Abstract MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) is a protoxicant that, after crossing the Blood Brain Barrier, is metabolized by astrocytic MAO-B to MPDP+, a pyridinium intermediate, which undergoes further two-electron oxidation to yield the toxic metabolite MPP+ (methyl-phenyltetrahydropyridinium) that is then selectively transported into nigral neurons via the mesencephalic dopamine transporter. In this study, we demonstrated that MPTP induced death of dopaminergic neurons, microgliosis, increase of gliapses, motor impairment and neuroinflammation in mice, which were inhibited by combined 1-deoxynojirimycin and ibuprofen treatment.


Asunto(s)
1-Desoxinojirimicina/farmacología , Neuronas Dopaminérgicas/efectos de los fármacos , Ibuprofeno/farmacología , Microglía/efectos de los fármacos , Fármacos Neuroprotectores/farmacología , Trastornos Parkinsonianos/patología , Animales , Antiinflamatorios/farmacología , Conducta Animal/efectos de los fármacos , Neuronas Dopaminérgicas/patología , Inhibidores Enzimáticos/farmacología , Masculino , Ratones , Ratones Endogámicos C57BL , Degeneración Nerviosa/patología , Fagocitosis/efectos de los fármacos
3.
Mol Biochem Parasitol ; 229: 35-46, 2019 04.
Artículo en Inglés | MEDLINE | ID: mdl-30797776

RESUMEN

Cestode development involves complex morphological and physiological changes. Here, we performed a differential expression analysis of gene transcripts between two developmental stages of the model cestode Mesocestoides corti. A RNA-seq-based approach was used to compare the transcriptomes of the tetrathyridium (larval, TT) and strobilated worm (ST) stages of the parasite. We found 19,053 transcripts, from which ∼45% were complete matches to genes previously annotated in the available M. corti draft genome sequence, ∼24% were considered novel isoforms, and ∼24% were considered potential novel transcripts. Stage-specific transcripts were found for both TTs (66) and STs (136), along with shared transcripts significantly overrepresented in one stage (342 in TTs, and 559 in STs). Differential expression and Gene Ontology term enrichment analyzes provided evidence of upregulation of different sets of transcripts associated with 'cytoskeleton', 'metabolism' and 'oxidation-reduction' processes in each stage, suggesting functional involvement of the corresponding genes with stage-specific features. Transcripts and processes enriched in the TT reflect typical larval processes that occur with the parasite in the intermediate host, such as asexual reproduction and budding, as well as active migration from the peritoneum to the liver and vice versa. In STs, transcripts associated with 'development', 'cell growth', and 'morphogenesis' were enriched, along with processes related to sexual reproduction, represented by the upregulation of numerous transcription factors, protein kinases, and histones. Overall, our results contributed to significantly increase the knowledge on the M. corti gene repertoire and expression profile in two developmental stages. Functional implications for the biology of larval and adult cestode parasites and for host-parasite interactions are discussed.


Asunto(s)
Infecciones por Cestodos/parasitología , Proteínas del Helminto/genética , Mesocestoides/crecimiento & desarrollo , Mesocestoides/genética , Animales , Femenino , Regulación del Desarrollo de la Expresión Génica , Proteínas del Helminto/metabolismo , Estadios del Ciclo de Vida , Mesocestoides/metabolismo , Ratones , Ratones Endogámicos BALB C , Transcriptoma
4.
Mol Ecol ; 26(20): 5541-5551, 2017 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-28802076

RESUMEN

Acid mine drainage (AMD) is characterized by an acid and metal-rich run-off that originates from mining systems. Despite having been studied for many decades, much remains unknown about the microbial community dynamics in AMD sites, especially during their early development, when the acidity is moderate. Here, we describe draft genome assemblies from single cells retrieved from an early-stage AMD sample. These cells belong to the genus Hydrotalea and are closely related to Hydrotalea flava. The phylogeny and average nucleotide identity analysis suggest that all single amplified genomes (SAGs) form two clades that may represent different strains. These cells have the genomic potential for denitrification, copper and other metal resistance. Two coexisting CRISPR-Cas loci were recovered across SAGs, and we observed heterogeneity in the population with regard to the spacer sequences, together with the loss of trailer-end spacers. Our results suggest that the genomes of Hydrotalea sp. strains studied here are adjusting to a quickly changing selective pressure at the microhabitat scale, and an important form of this selective pressure is infection by foreign DNA.


Asunto(s)
Bacteroidetes/clasificación , Repeticiones Palindrómicas Cortas Agrupadas y Regularmente Espaciadas , Genoma Bacteriano , Minería , Ácidos , Bacteroidetes/genética , ADN Bacteriano/genética , Ecosistema , Evolución Molecular , Filogenia , Análisis de Secuencia de ADN , Análisis de la Célula Individual
6.
Braz J Med Biol Res ; 50(7): e5782, 2017 Jul 03.
Artículo en Inglés | MEDLINE | ID: mdl-28678915

RESUMEN

Endometriosis is a benign, estrogen-dependent disease with symptoms such as pelvic pain and infertility, and it is characterized by the ectopic distribution of endometrial tissue. The expression of the ID2, PRELP and SMOC2 genes was compared between the endometrium of women without endometriosis in the proliferative phase of their menstrual cycle and the eutopic and ectopic endometrium of women with endometriosis in the proliferative phase. Paired tissue samples from 20 women were analyzed: 10 from endometrial and peritoneal endometriotic lesions and 10 from endometrial and ovarian endometriotic lesions. As controls, 16 endometrium samples were collected from women without endometriosis in the proliferative phase of menstrual cycle. Analysis was performed by real-time polymerase chain reaction (PCR). There was no significant difference between gene expression in the endometrium of women with and without endometriosis. The ID2 gene expression was increased in the most advanced stage of endometriosis and in ovarian endometriomas, the PRELP was more expressed in peritoneal lesions, and the SMOC2 was highly expressed in both peritoneal and endometrioma lesions. Considering that the genes studied participate either directly or indirectly in cellular processes that can lead to cell migration, angiogenesis, and inappropriate invasion, it is possible that the deregulation of these genes caused the development and maintenance of ectopic tissue.


Asunto(s)
Endometriosis/genética , Proteínas de la Matriz Extracelular/genética , Glicoproteínas/genética , Proteína 2 Inhibidora de la Diferenciación/genética , Osteonectina/genética , Enfermedades del Ovario/genética , Enfermedades Peritoneales/genética , Adolescente , Adulto , Estudios de Casos y Controles , Endometriosis/metabolismo , Proteínas de la Matriz Extracelular/metabolismo , Femenino , Regulación de la Expresión Génica , Glicoproteínas/metabolismo , Humanos , Proteína 2 Inhibidora de la Diferenciación/metabolismo , Ciclo Menstrual , Osteonectina/metabolismo , Enfermedades del Ovario/metabolismo , Enfermedades Peritoneales/metabolismo , Reacción en Cadena en Tiempo Real de la Polimerasa , Adulto Joven
7.
Braz. j. med. biol. res ; 50(7): e5782, 2017. graf
Artículo en Inglés | LILACS | ID: biblio-951699

RESUMEN

Endometriosis is a benign, estrogen-dependent disease with symptoms such as pelvic pain and infertility, and it is characterized by the ectopic distribution of endometrial tissue. The expression of the ID2, PRELP and SMOC2 genes was compared between the endometrium of women without endometriosis in the proliferative phase of their menstrual cycle and the eutopic and ectopic endometrium of women with endometriosis in the proliferative phase. Paired tissue samples from 20 women were analyzed: 10 from endometrial and peritoneal endometriotic lesions and 10 from endometrial and ovarian endometriotic lesions. As controls, 16 endometrium samples were collected from women without endometriosis in the proliferative phase of menstrual cycle. Analysis was performed by real-time polymerase chain reaction (PCR). There was no significant difference between gene expression in the endometrium of women with and without endometriosis. The ID2 gene expression was increased in the most advanced stage of endometriosis and in ovarian endometriomas, the PRELP was more expressed in peritoneal lesions, and the SMOC2 was highly expressed in both peritoneal and endometrioma lesions. Considering that the genes studied participate either directly or indirectly in cellular processes that can lead to cell migration, angiogenesis, and inappropriate invasion, it is possible that the deregulation of these genes caused the development and maintenance of ectopic tissue.


Asunto(s)
Humanos , Femenino , Adolescente , Adulto , Adulto Joven , Enfermedades Peritoneales/genética , Glicoproteínas/genética , Osteonectina/genética , Proteínas de la Matriz Extracelular/genética , Endometriosis/genética , Proteína 2 Inhibidora de la Diferenciación/genética , Glicoproteínas/metabolismo , Estudios de Casos y Controles , Regulación de la Expresión Génica , Proteínas de la Matriz Extracelular/metabolismo , Endometriosis/metabolismo , Proteína 2 Inhibidora de la Diferenciación/metabolismo , Reacción en Cadena en Tiempo Real de la Polimerasa , Ciclo Menstrual
8.
Genet Mol Res ; 13(1): 838-49, 2014 Feb 13.
Artículo en Inglés | MEDLINE | ID: mdl-24615048

RESUMEN

The chicken (Gallus gallus) embryo has been used as a classic model system for developmental studies because of its easy accessibility for surgical manipulation during embryonic development. Sex determination in birds is chromosomally based (ZZ for males and ZW for females); however, the basic mechanism of sex determination is still unknown. Here, the dynamics of expression of candidate genes implicated in vertebrate sex determination and differentiation were studied during embryonic chicken gonadal development. Gene expression profiles were obtained before, during, and after gonadal sex differentiation in females and males for DMRT1, SOX3, SOX9, DAX1, SCII, HINTZ, HINTW, and the male hypermethylated (MHM) region. Transcripts for the HINTZ, DMRT1, DAX1, SCII, and SOX9 genes were observed in both sexes, but expression was higher in male gonads and may be correlated with testicular differentiation. The expression patterns of HINTW, SOX3, and MHM suggest that they may act in ovary development and may be involved in meiosis entry. MHM was upregulated and DMRT1 was downregulated in females at the same developmental stage. This may indicate a regulation of DMRT1 by MHM ncRNA. Similar dynamics were observed between HINTW and HINTZ. This study reports on the MHM expression profile during gonadal development and its correlation with the expression of genes involved in vertebrate sex determination.


Asunto(s)
Gónadas/crecimiento & desarrollo , Procesos de Determinación del Sexo , Diferenciación Sexual/genética , Animales , Embrión de Pollo , Metilación de ADN/genética , Femenino , Regulación del Desarrollo de la Expresión Génica , Masculino , Cromosomas Sexuales/genética , Testículo/crecimiento & desarrollo , Testículo/metabolismo
9.
Neurology ; 78(10): 736-42, 2012 Mar 06.
Artículo en Inglés | MEDLINE | ID: mdl-22357720

RESUMEN

OBJECTIVE: This study aimed to determine the frequency of CNS infection by dengue virus (DENV) in individuals with fatal outcomes. METHODS: Samples of 150 individuals suspect of an infection disease and with fatal outcomes were investigated for evidence of the presence of DENV. The sampling was made up of 150 CSF, 120 tissue samples, and 109 blood specimens. The tests used were viral isolation, reverse transcriptase PCR, immunohistochemistry, nonstructural 1 antigen, and immunoglobulin M detection. RESULTS: Out of 150 studied patients, 84 were dengue positive. Evidence of the presence of DENV was found in 41 CSF, showing the following neurologic diagnosis: 46.3% encephalitis, 34.1% meningoencephalitis, and 19.5% meningitis, giving a frequency of 48.8% of the 84 dengue-positive cases. The major clinical manifestations observed on these individuals were fever, headache, mental irritability, breathless, vomiting, muscle pain, tiredness, abdominal pain, somnolence, restlessness, dizziness, cough, seizure, coma, and neck stiffness. CONCLUSION: Clinical manifestations and laboratory-positive results in CSF that may indicate the presence of DENV led to consider the invasion of CNS by DENV in these fatal cases studied, and showed that neurologic pathology was an important fatal complication in dengue cases.


Asunto(s)
Enfermedades Virales del Sistema Nervioso Central/diagnóstico , Virus del Dengue/aislamiento & purificación , Dengue/diagnóstico , Encefalitis Viral/diagnóstico , Meningoencefalitis/diagnóstico , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Enfermedades Virales del Sistema Nervioso Central/etiología , Niño , Preescolar , Dengue/complicaciones , Encefalitis Viral/etiología , Femenino , Humanos , Lactante , Masculino , Meningoencefalitis/virología , Persona de Mediana Edad
10.
J Virol Methods ; 177(1): 128-31, 2011 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-21798288

RESUMEN

The involvement of the central nervous system in dengue infections has been reported in countries where the disease in endemic. The purpose of this study was to determine whether an enzyme-linked immunosorbent assay kit designed to detect the dengue NS1 antigen in serum was able to detect this antigen in cerebral spinal fluid (CSF) samples from patients with fatal outcomes. To evaluate the sensitivity of the kit, 26 dengue-positive CSF samples were used. The Pan-E Dengue Early kit was able to detect the NS1 antigen in 13 of 26 dengue-positive CSF samples, resulting in a sensitivity of 50% (95% confidence interval, 29.9-70.1%) and specificity of 100% (95% confidence interval, 75.3-100%). The kit was able to detect the NS1 antigen in CSF of individuals who had died of dengue. When used in combination with IgM, the detection rate rose to 92.3%. This study reports a method for rapidly detecting the dengue virus in CSF, thereby increasing the diagnosis of dengue fever cases with unusual neurological manifestations.


Asunto(s)
Antígenos Virales/líquido cefalorraquídeo , Virus del Dengue/inmunología , Dengue/diagnóstico , Ensayo de Inmunoadsorción Enzimática , Juego de Reactivos para Diagnóstico , Proteínas no Estructurales Virales/líquido cefalorraquídeo , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Antígenos Virales/inmunología , Niño , Preescolar , Dengue/inmunología , Femenino , Humanos , Inmunoglobulina M/sangre , Inmunoglobulina M/líquido cefalorraquídeo , Lactante , Masculino , Persona de Mediana Edad , Sensibilidad y Especificidad , Proteínas no Estructurales Virales/inmunología , Adulto Joven
11.
Opt Express ; 17(21): 18669-75, 2009 Oct 12.
Artículo en Inglés | MEDLINE | ID: mdl-20372599

RESUMEN

In this work, sensitivity to strain and temperature of a sensor relying on modal interferometry in hollow-core photonic crystal fibers is studied. The sensing structure is simply a piece of hollow-core fiber connected in both ends to standard single mode fiber. An interference pattern that is associated to the interference of light that propagates in the hollow core fundamental mode with light that propagates in other modes is observed. The phase of this interference pattern changes with the measurand interaction, which is the basis for considering this structure for sensing. The phase recovery is performed using a white light interferometric technique. Resolutions of +/- 1.4 microepsilon and +/- 0.2 degrees C were achieved for strain and temperature, respectively. It was also found that the fiber structure is not sensitive to curvature.

12.
Opt Lett ; 32(21): 3074-6, 2007 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-17975601

RESUMEN

A novel Mach-Zehnder interferometer based on a fiber multimode interference structure combined with a long-period fiber grating (LPG) is proposed. The multimode interference is achieved through the use of a MMF section spliced between two single-mode fibers, with a length adjusted to couple a fraction of light into the cladding modes. A LPG placed after the MMF couples light back into the fiber core, completing the Mach-Zehnder interferometer. This novel configuration was demonstrated as a bending sensor.

13.
Appl Opt ; 46(32): 7900-5, 2007 Nov 10.
Artículo en Inglés | MEDLINE | ID: mdl-17994142

RESUMEN

An absorption-line-locked fiber laser based on the selection and conversion of a gas absorption line into a highly stable intracavity transmission narrowband filter is demonstrated. The laser has attractive properties for gas-sensing applications due to its frequency stability and multiwavelength selection capability.

14.
Hypertens Pregnancy ; 26(3): 357-62, 2007.
Artículo en Inglés | MEDLINE | ID: mdl-17710583

RESUMEN

OBJECTIVE: To verify the occurrence of preeclampsia/eclampsia (PE/E) or gestational hypertension (GH) in first-degree relatives of Brazilian pregnant women. METHODS: A total of 485 women were enrolled in the study, and 226 were selected (75 with PE/E, 49 with GH, and 102 women with normal pregnancies). Statistical analysis was performed using Fisher's exact test. RESULTS: The frequency of families with mothers and/or sisters with PE/E was higher among the PE/E group compared to the GH and the control groups, and was statistically significant (p < 0.05). CONCLUSION: Women with PE/E have more female first-degree relatives with PE/E as observed in a Brazilian population.


Asunto(s)
Hipertensión Inducida en el Embarazo/genética , Brasil , Familia , Femenino , Humanos , Embarazo
15.
Opt Lett ; 32(14): 1974-6, 2007 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-17632614

RESUMEN

A novel in-fiber modal interferometer is presented that is based on a nonadiabatic biconical fused taper that couples light between the cladding and the core, combined with the Fresnel reflection at the fiber end. It is observed that the returned light from this fiber structure shows a channeled spectrum similar to that of a two-wave Michelson interferometer. The application of this device as a fiber optic flowmeter sensor is demonstrated.

16.
Opt Lett ; 31(20): 2960-2, 2006 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-17001366

RESUMEN

A new concept to measure rotation angles based on a fiber-optic modal Mach-Zehnder interferometer is demonstrated by using a nonadiabatic taper cascaded with a long-period fiber grating. Information about the magnitude of the rotation angle can be obtained from the measurement of the interference pattern visibility, and under certain conditions it is also possible to obtain the sign of the rotation angle from the induced phase variation in the fiber interferometer.

17.
Appl Opt ; 44(18): 3821-6, 2005 Jun 20.
Artículo en Inglés | MEDLINE | ID: mdl-15989057

RESUMEN

An intensity-referenced temperature-independent curvature-measurement technique that uses a smart composite that comprises two chirped fiber Bragg gratings is demonstrated. The two gratings are embedded on opposite sides of the composite laminate and act simultaneously as curvature sensors and as wavelength discriminators, enabling a temperature-independent intensity-based scheme to measure radius of curvature. Also, the system's performance is independent of arbitrary power losses that are induced in the lead fibers to the sensing head. It is demonstrated that the measurement range depends on the relative positions of the chirped fiber Bragg gratings and on their spectral bandwidths. By using two chirped fiber Bragg gratings with bandwidths W1 = 2.8 nm and W2 = 3.7 nm and with central wavelengths at lambda 01 = 1560.3 nm and lambda 02 = 1563.7 nm, we obtained a resolution of 1.6 mm/square root of Hz for the measurement of the radius of curvature (approximately R = 350 mm) over the measurement range 190 mm < R < infinity.

18.
Parasitology ; 130(Pt 4): 413-20, 2005 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-15830815

RESUMEN

Blastocrithidia culicis is an insect trypanosomatid that presents bacterial endosymbionts. The cell-associated and secreted proteinases of the endosymbiont-bearing and aposymbiotic strains were compared through the incorporation of proteinaceous substrates into sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Few qualitative changes could be detected in the proteolytic zymograms in the 2 strains studied when gelatin, casein, haemoglobin or bovine serum albumin (BSA) were tested. However, the level of proteolytic activities was significantly higher in the aposymbiotic strain. Some of the B. culicis proteins reacted in Western blots with antibodies raised against gp63, a zinc-metalloproteinase, and cruzipain, a cysteinyl-proteinase, which are virulence factors of the human pathogenic trypanosomatids, Leishmania spp. and Trypanosoma cruzi, respectively. The anti-cross-reacting determinant (CRD) antibody recognized 2 polypeptides (50 and 58 kDa) in the spent culture media and in the supernatant from glycosylphosphatidylinositol-phospholipase C (GPI-PLC)-treated cells, suggesting that these proteins are GPI-anchored to the plasma membrane. In addition, the anti-gp63 reacted with the 50 kDa protein. The identification of protein homologues in trypanosomatids with distinct life-cycles may help to determine the importance of proteinases in trypanosomatids.


Asunto(s)
Péptido Hidrolasas/metabolismo , Trypanosomatina/enzimología , Animales , Western Blotting , Caseínas/metabolismo , Cisteína Endopeptidasas/metabolismo , Electroforesis en Gel de Poliacrilamida , Gelatina/metabolismo , Glicosilfosfatidilinositol Diacilglicerol-Liasa , Hemoglobinas/metabolismo , Metaloendopeptidasas/metabolismo , Fosfatidilinositol Diacilglicerol-Liasa/metabolismo , Proteínas Protozoarias , Albúmina Sérica Bovina/metabolismo , Simbiosis/fisiología , Trypanosomatina/fisiología
19.
Appl Opt ; 41(13): 2401-7, 2002 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-12009148

RESUMEN

We present what we believe to be a novel miniaturized sensor configuration based on fiber Bragg gratings for simultaneous measurement of curvature and temperature in smart structures and composite materials. Because of the particular geometry of the sensing head, it is possible not only to measure the radius of curvature but also to determine the plane of curvature. We arrange three Bragg gratings in the vertices of the smallest equilateral triangle that can be defined by the cross sections of the fibers. The set is then inserted into a glue-filled capillary stainless-steel tube to provide both suitable protection for the Bragg sensors and rotational symmetry to the sensing head. This tube also ensures isolation from axial strain, allowing for the additional determination of temperature. The proposed sensing head is particularly well suited for applications in smart structures because it can be embedded along any layer of a composite material (including the neutral line) without special concern for the relative orientation of the Bragg gratings and the composite layers. We can also use this sensing configuration to implement more-sophisticated sensors dedicated, for example, to the measurement of multiaxial acceleration or flow and temperature.

20.
Acta Trop ; 81(1): 21-31, 2002 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-11755429

RESUMEN

In this study, the polymerase chain reaction (PCR) was compared with parasitological and serological methods to detect the infection in dogs, 5-12 years after experimental infection with Trypanosoma cruzi. The ability of parasitological methods to identify a positive animal was 22 and 11% by hemoculture and xenodiagnosis/xenoculture, respectively. On the other hand, the serological tests, including conventional serology and anti-live trypomastigote antibodies (ALTA) were positive in all infected dogs. Despite its low sensitivity, if considering only one reaction, the PCR analysis showed 100% of positivity, demonstrating the presence of parasite kDNA in all infected dogs. To identify a positive dog required at least two blood samples and up to nine repeated reactions using the same sample. Serial blood sample collection, ranging from 1 to 9, revealed that the percentage of dogs with positive PCR ranged from 67 to 100%. These findings suggested that, although the PCR is useful to detect the parasite in infected hosts, it should not be used isolated for the diagnosis of Chagas' disease and warn for the necessity of serial blood collection and re-tests. Moreover, these data validate once more the dog as a model for Chagas' disease since they demonstrate the permanence of infection by PCR, parasitological and serological methods, reaching relevant requisites for an ideal model to study this disease.


Asunto(s)
Anticuerpos Antiprotozoarios/sangre , Enfermedad de Chagas/diagnóstico , Trypanosoma cruzi , Animales , Enfermedad Crónica , ADN Protozoario/análisis , Modelos Animales de Enfermedad , Perros , Ensayo de Inmunoadsorción Enzimática , Estudios de Seguimiento , Reacción en Cadena de la Polimerasa , Trypanosoma cruzi/aislamiento & purificación , Xenodiagnóstico
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