RESUMEN
The active rift zones in Iceland provide unique insight into the geodynamic processes of divergent plate boundaries. The geodynamics of Iceland are studied intensively, particularly, by geophysical methods sensitive to active and/or visible structures such as earthquake seismic and Synthetic Aperture Radar observations or aerial photographs. However, older and less active structures, that may exert a strong control on the presently active geodynamics, are often buried beneath recent volcanic or sedimentary deposits and are-due to their passive mode-overseen by the typical geophysical investigations. Aeromagnetic surveys provide spatial information about subsurface magnetization contrasts relating to both active and inactive structures. However, the aeromagnetic data in Iceland were collected in the 1970-80s and are relevant only to large-scale regional rift studies. With the availability of reliable drones and light-weight atomic scalar sensors, high-quality drone magnetic surveys can provide an unprecedented spatial resolution of both active and passive structures of rift systems as compared to conventional airborne surveys. Here, we present the results of a drone-towed magnetic scalar field and scalar gradiometry study of the north-northeast trending Bárðarbunga spreading center to the north of the Vatnajökull ice cap, Iceland. Our results provide new information about the structural complexity of rift zones with evidence of densely-spaced, conjugate and oblique faults throughout the area. Evidence is shown of a hitherto unknown and prominent east-northeast trending fault structure that coincides with the northern tip of the main eruption edifice of the 1797 and 2014-15 Holuhraun volcanic events. We suggest that this pre-existing structure controlled the locus of vertical magma migration during the two Holuhraun events.
RESUMEN
Among the unique opportunities and developments that are currently being triggered by the fourth industrial revolution, developments in cutting tools have been following the trend of an ever more holistic control of manufacturing processes. Sustainable manufacturing is at the forefront of tools development, encompassing environmental, economic, and technological goals. The integrated use of sensors, data processing, and smart algorithms for fast optimization or real time adjustment of cutting processes can lead to a significant impact on productivity and energy uptake, as well as less usage of cutting fluids. Diamond is the material of choice for machining of non-ferrous alloys, composites, and ultrahard materials. While the extreme hardness, thermal conductivity, and wear resistance of CVD diamond coatings are well-known, these also exhibit highly auspicious sensing properties through doping with boron and other elements. The present study focuses on the thermal response of boron-doped diamond (BDD) coatings. BDD coatings have been shown to have a negative temperature coefficient (NTC). Several approaches have been adopted for monitoring cutting temperature, including thin film thermocouples and infrared thermography. Although these are good solutions, they can be costly and become impractical for certain finishing cutting operations, tool geometries such as rotary tools, as well as during material removal in intricate spaces. In the scope of this study, diamond/WC-Co substrates were coated with BDD by hot filament chemical vapor deposition (HFCVD). Scanning electron microscopy, Raman spectroscopy, and the van der Pauw method were used for morphological, structural, and electrical characterization, respectively. The thermal response of the thin diamond thermistors was characterized in the temperature interval of 20-400 °C. Compared to state-of-the-art temperature monitoring solutions, this is a one-step approach that improves the wear properties and heat dissipation of carbide tools while providing real-time and in-situ temperature monitoring.
RESUMEN
Cobalt-cemented carbide micro-end mills were coated with diamond grown by chemical vapor deposition (CVD), with the purpose of micro-machining cemented carbides. The diamond coatings were designed with a multilayer architecture, alternating between sub-microcrystalline and nanocrystalline diamond layers. The structure of the coatings was studied by transmission electron microscopy. High adhesion to the chemically pre-treated WC-7Co tool substrates was observed by Rockwell C indentation, with the diamond coatings withstanding a critical load of 1250 N. The coated tools were tested for micro-end-milling of WC-15Co under air-cooling conditions, being able to cut more than 6500 m over a period of 120 min, after which a flank wear of 47.8 µm was attained. The machining performance and wear behavior of the micro-cutters was studied by scanning electron microscopy and energy-dispersive X-ray spectroscopy. Crystallographic analysis through cross-sectional selected area electron diffraction patterns, along with characterization in dark-field and HRTEM modes, provided a possible correlation between interfacial stress relaxation and wear properties of the coatings. Overall, this work demonstrates that high adhesion of diamond coatings can be achieved by proper combination of chemical attack and coating architecture. By preventing catastrophic delamination, multilayer CVD diamond coatings are central towards the enhancement of the wear properties and mechanical robustness of carbide tools used for micro-machining of ultra-hard materials.
RESUMEN
The consumption of dissolved oxygen (DO) during the corrosion of commercially pure magnesium specimens was investigated by localized corrosion techniques. The concentration of oxygen and the local current density on the near-surface of magnesium were measured simultaneously by a micro-optode DO sensor and the scanning vibrating electrode technique (SVET), respectively. Diamond microelectrodes were also used for DO mapping. Significant DO depletion was found since the initial immersion time of Mg in NaCl 0.5 m, and a correlation could be established between DO consumption and areas of anodic and cathodic activity. These findings assume particular relevance for the corrosion of Mg alloys or magnesium components with impurity levels higher than the tolerance limit. Moreover, this study points out the significance of the partial oxygen pressure as an influential parameter during magnesium corrosion.
RESUMEN
Doença do corpúsculo de inclusão (IBD) é uma enfermidade caracterizada por corpúsculos intracitoplasmáticos em diversos tecidos, principalmente no sistema nervoso central, responsável pelos principais sinais clínicos atribuídos à doença que acomete Boas e Phytons de cativeiro; essa enfermidade tem sido uma preocupação mundial devido à alta morbidade e mortalidade. O diagnóstico é feito pela visualização dos corpúsculos causados por um Arenavírus modificado. Salmonella sp. pertence à microflora de animais de sangue frio e quente, e é um patógeno oportunista que pode causar quadros gastrointestinais ou septicêmicos. Em répteis a Salmonella sp. é a bactéria com maior frequência de citações em espondilites e osteomielites. Relata-se um caso de uma jiboia (Boa constrictor constrictor) que apresentava restrição de movimento e múltiplos granulomas dorsais nas vértebras; à radiografia evidenciaram-se regiões fraturadas. Após meses de tratamentos sem melhora clínica e o aparecimento de novas lesões o animal ficou prostrado, anoréxico, caquético e desenvolveu opistótono; optou-se pela eutanásia. À necropsia verificaram-se, nas vértebras, múltiplos focos dorsais com aumento de volume que variava de 1,7cm à 3,8cm. Ao corte as vértebras eram deformadas e exibiam conteúdo caseoso focal próximo ao canal medular, este foi coletado para microbiologia onde se identificou Salmonella sp. À microscopia as vértebras tinham um infiltrado inflamatório multifocal moderado de macrófagos e heterofilos. Algumas áreas possuíam grande quantidade de granulomas com calcificação central e inúmeras células gigantes; outros mostravam áreas de osteomalácia e fibrose. Em raros focos havia fratura do corpo vertebral e compressão da medula espinhal com leve infiltrado inflamatório invadindo o canal medular. No pulmão, principalmente no epitélio brônquico, por vezes até dentro de linfócitos do tecido linfoide bronco-associado, no intestino, fígado, vesícula biliar, nos rins e no encéfalo foram encontradas diversas estruturas eosinofílicas intracitoplasmáticas arredondadas que variavam de 1 a 10 µm. Essas estruturas acompanhavam ou não inflamações mononucleares. Os achados são compatíveis com IBD e espondilite por salmonelose. A IBD é uma enfermidade frequente em serpentes de cativeiro, de importância mundial, que provavelmente é subdiagnosticada no Brasil. Essa doença causa imunossupressão que favorece ao desenvolvimento de outras enfermidades, e é tipicamente associada a outras doenças como a espondilite encontrada no caso.(AU)
Inclusion Body Disease (IBD) is a disorder characterized by intracytoplasmic corpuscles in different tissues, mainly in the CNS, wich is responsible for the major neurological signs attributable to this disease. It affects Boas and Phytons in captivity and have been a global concern due to the high morbidity and mortality. The diagnosis is made by visualization of corpuscles caused by a modified Arenaviruses. Salmonella sp. belongs to microflora of cold and warm-blooded animals; it is an opportunistic pathogen that can causes gastrointestinal or septic disorders. In reptiles, Salmonella sp. is the bacteria most frequently quotes in spondylitis and osteomyelitis. This article describes a boa constrictor (Boa constrictor constrictor) that had restriction of movement and multiple granulomas in the dorsal vertebrae, the shadowgraph showed up fractured regions. After months of treatment without clinical improvement and the emergence of new injuries, the animal started to get prostrate, anorexic, cachectic and developed opisthotonos. It was opted for euthanasia. At necropsy it was found in multiple spots swelling of the dorsal vertebrae that ranging from mild to moderate. At the cutting vertebrae it was visible deformed and showed focal caseous content near the spinal cord, this was collected for microbiology where it was identified Salmonella sp. At microscopic evaluation the vertebrae had one to multifocal moderate inflammatory infiltrate of macrophages and heterophils. Some areas had lots of granulomas with central calcification and numerous giant cells. Other vertebras showed areas of osteomalácea and fibrosis. Rare focus had vertebral body fracture and spinal cord compression with mild infiltration entering the spinal cord canal. In the lung, especially in the bronchial epithelium, sometimes even within lymphocytes in bronchial-associated lymphoid tissue, in the intestine, liver, gall bladder, kidney and brain were found various structures of eosinophilic intracytoplasmic rounded ranging between 1 and 10 micrometers. These structures accompanied or not mononuclear inflammation. These findings are consistent with IBD and spondylitis due to salmonellosis. The IBD is a common disease in captive snakes, of world importance, is probably underdiagnosed in Brazil. This disease causes immunosuppression favoring the development of other affections, and is typically associated with other diseases such as spondylitis found in the case.(AU)
Asunto(s)
Animales , Salmonella/aislamiento & purificación , Salmonelosis Animal , Serpientes/microbiología , Espondilitis/veterinaria , Cuerpos de Inclusión , ArenavirusRESUMEN
Este trabalho apresenta valores hematológicos e bioquímicos de pinguins-de-Magalhães (Spheniscus magellanicus) juvenis que arribaram no Espírito Santo e Rio de Janeiro, litoral sudeste do Brasil, e foram encaminhados a reabilitação. Os valores médios obtidos foram: eritrócitos 2.55±0.54 milhões/µL; hemoglobina 13,37±3,91g/dL; hematócrito 41,5±0,04%; proteína plasmática 6,34±0,81g/dL; leucócitos 16.301±6.402/µL; trombócitos 20.516±4.591 células/µL; volume corpuscular médio (VCM) 172,0±53,0 fL; concentração de hemoglobina corpuscular média (CHCM) 26,41±0,02%; alanina transaminase (ALT) 50,0±17,89 U/L; ácido úrico 8,93±3,0mg/dL; albumina 1,68±0,53g/dL; cálcio 9,7±0,57mg/dL; fósforo 10,39±8,5mg/dL e glicose 211,6±30,3mg/dL. Valores de eritrócitos, VCM e CHCM foram discrepantes em relação aos valores de referência atuais. Valores de leucócitos e trombócitos tem significado inconclusivo. Hematócrito, hemoglobina, proteína plasmática e valores bioquímicos forneceram importante contribuição para o estabelecimento de parâmetros de referência.(AU)
This paper reports hematological and biochemical values of juveniles Magellanic penguins (Spheniscus magellanicus) stranded in Espírito Santo and Rio de Janeiro, Southeastern Brazil, that were sent for rehabilitation. The average values were: erythrocytes 2.55±0,54 milhões/µL, hemoglobin 13.37±3,91g/dL, hematocrit 41.5±0.04%, plasma protein 6.34±0.81g/dL, leukocytes 16,301±6,402/µL, thrombocytes 20,516±4,591 células/µL3, mean cell volume (MCV) 172.0±53.0 fL, mean cell hemoglobin concentration (MCHC) 26.41±0.02%, alanine transaminase (ALT) 50.0±17.89 U/L, uric acid 8.93±3.0mg/dL, albumin 1.68±0.53mg/dL, calcium 9.7±0.57mg/dL, phosphorus 10.39±8.5mg/dL and glucose 211.6±30.3mg/dL. Values of erythrocytes, MCV and MCH were discrepant in relation to the current reference values. Leukocytes and thrombocytes values has meant inconclusive. Hematocrit, hemoglobin, plasma protein and biochemical values provided important contribution for the establishment of reference parameters.(AU)
Asunto(s)
Animales , Fenómenos Bioquímicos , Análisis Químico de la Sangre/veterinaria , Rehabilitación , Spheniscidae/sangre , Pruebas Hematológicas/veterinariaRESUMEN
The fabrication of an all-diamond microprobe is demonstrated for the first time. This ME (microelectrode) assembly consists of an inner boron doped diamond (BDD) layer and an outer undoped diamond layer. Both layers were grown on a sharp tungsten tip by chemical vapor deposition (CVD) in a stepwise manner within a single deposition run. BDD is a material with proven potential as an electrochemical sensor. Undoped CVD diamond is an insulating material with superior chemical stability in comparison to conventional insulators. Focused ion beam (FIB) cutting of the apex of the ME was used to expose an electroactive BDD disk. By cyclic voltammetry, the redox reaction of ferrocenemethanol was shown to take place at the BDD microdisk surface. In order to ensure that the outer layer was nonelectrically conductive, a diffusion barrier for boron atoms was established seeking the formation of boron-hydrogen complexes at the interface between the doped and the undoped diamond layers. The applicability of the microelectrodes in localized corrosion was demonstrated by scanning amperometric measurements of oxygen distribution above an Al-Cu-CFRP (Carbon Fiber Reinforced Polymer) galvanic corrosion cell.
Asunto(s)
Diamante , Técnicas Electroquímicas/instrumentación , Microelectrodos , Sondas MolecularesRESUMEN
Os répteis possuem um sistema porta-renal, o qual pode desviar parte do sangue proveniente das porções caudais do corpo aos rins antes que a mesma atinja a circulação sistêmica. Em vista disto, vem sendo aconselhada a administração de medicamentos injetáveis nos membros torácicos, para que se evite a filtração imediata pelo parênquima renal, causando redução do efeito esperado. O objetivo do presente estudo foi comparar aspectos qualitativos e quantitativos da associação de cetamina (30 mg/kg) e xilazina (1 mg/kg), injetada no membro torácico ou pélvico, em jacarés-do-papo-amarelo (Caiman latirostris) juvenis. Oito animais machos com peso médio (±DP) de 1,3 (±0,3) kg e, aproximadamente, dois anos de idade foram anestesiados em duas ocasiões distintas com intervalo de sete dias. Em cada ocasião, os animais receberam, de forma aleatória, a associação anestésica por via intramuscular em membro torácico (tratamento MT) ou pélvico (tratamento MP). Foram avaliados os intervalos de tempo entre a administração do tratamento e a perda do reflexo de endireitamento (período de indução), entre a perda e o retorno desse reflexo (duração do efeito clínico importante) e entre o retorno do reflexo de endireitamento e os primeiros movimentos de deambulação (duração do efeito residual), as frequências cardíaca e respiratória e as temperaturas ambiental e cloacal. Os escores de sedação/anestesia foram avaliados através de uma escala com variação de 0 (alerta/consciente) a 10 (anestesia profunda/sobredosagem). No tratamento MP, dois animais não apresentaram perda de reflexo de endireitamento. Considerando somente aqueles que apresentaram a perda desse reflexo, o tempo de indução (21±9 e 17±5 minutos) e a duração do efeito clínico importante (35±19 e 43±21 minutos) e residual (28±31 e 12±11 minutos) foram similares entre os tratamentos MT e MP (média±desvio padrão)...
Reptiles possess a renal portal system which can divert part of the blood from the caudal portions of the body to the kidney before it reaches the systemic circulation. In view of this, it has been recommended the administration of injectable medications in the forelimbs, in order to avoid immediate glomerular filtration, which might result in a reduction of the expected effect. The aim of this study was to compare qualitative and quantitative aspects of the pharmacological restraint provided by the combination of ketamine (30mg/kg) and xylazine (1mg/kg), injected into the forelimb or hindlimb, in broad-snouted caiman juveniles (Caiman latirostris). Eight male animals, with a mean weight (±SD) of 1.3 (±0.3) kg, and aged about 2 years old, were anesthetized on two separate occasions with an interval of 7 days. On each occasion, the animals were randomly assigned to receive the anesthetic combination intramuscularly into the forelimb (FL treatment) or hindlimb (HL treatment). The time intervals between administration of treatment and loss of the righting reflex (induction time), between the loss and return of this reflex (duration of important clinical effect), and between the return of the righting reflex and first movements of ambulation (duration of residual effect) were measured as well as heart and respiratory rates and cloacal and environmental temperatures. Sedation/anesthesia scores were evaluated using a scale ranging from 0 (alert/conscious) to 10 (deep anesthesia/overdose). In the HL treatment, loss of righting reflex was not observed in two animals. Considering only those animals whose loss of righting reflex was observed, the induction time (21±9 and 17±5 minutes), the duration of important clinical effect (35±19 and 43±21 minutes), and the duration of residual effect (28±31 and 12±11 minutes) were similar between the FL and HL treatments, respectively (mean±SD). Sedation/anesthesia scores were significantly higher than at baseline...
Asunto(s)
Animales , Anestésicos Disociativos/efectos adversos , Caimanes y Cocodrilos/metabolismo , Ketamina/administración & dosificación , Miembro Anterior , Pelvis , Xilazina/administración & dosificación , Circulación Renal , Sedación Profunda/veterinariaRESUMEN
After the first description of TSP/HAM in 1985 and the elaboration of WHO's diagnostic criteria in 1988, the experience of the professionals in this field has increased so that a critical reappraisal of these diagnostic guidelines was considered timely. Brazilian neurologists and observers from other countries met recently to discuss and propose a modified model for diagnosing TSP/HAM with levels of ascertainment as definite, probable, and possible, according to myelopathic symptoms, serological findings, and/or detection of HTLV-I DNA and exclusion of other disorders.