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Asymptotic giant branch stars are responsible for the production of most of the heavy isotopes beyond Sr observed in the solar system. Among them, isotopes shielded from the r-process contribution by their stable isobars are defined as s-only nuclei. For a long time the abundance of ^{204}Pb, the heaviest s-only isotope, has been a topic of debate because state-of-the-art stellar models appeared to systematically underestimate its solar abundance. Besides the impact of uncertainties from stellar models and galactic chemical evolution simulations, this discrepancy was further obscured by rather divergent theoretical estimates for the neutron capture cross section of its radioactive precursor in the neutron-capture flow, ^{204}Tl (t_{1/2}=3.78 yr), and by the lack of experimental data on this reaction. We present the first ever neutron capture measurement on ^{204}Tl, conducted at the CERN neutron time-of-flight facility n_TOF, employing a sample of only 9 mg of ^{204}Tl produced at the Institute Laue Langevin high flux reactor. By complementing our new results with semiempirical calculations we obtained, at the s-process temperatures of kT≈8 keV and kT≈30 keV, Maxwellian-averaged cross sections (MACS) of 580(168) mb and 260(90) mb, respectively. These figures are about 3% lower and 20% higher than the corresponding values widely used in astrophysical calculations, which were based only on theoretical calculations. By using the new ^{204}Tl MACS, the uncertainty arising from the ^{204}Tl(n,γ) cross section on the s-process abundance of ^{204}Pb has been reduced from â¼30% down to +8%/-6%, and the s-process calculations are in agreement with the latest solar system abundance of ^{204}Pb reported by K. Lodders in 2021.
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Neutron capture reaction cross sections on 74 Ge are of importance to determine 74 Ge production during the astrophysical slow neutron capture process. We present new resonance data on 74 Ge( n , γ ) reactions below 70 keV neutron energy. We calculate Maxwellian averaged cross sections, combining our data below 70 keV with evaluated cross sections at higher neutron energies. Our stellar cross sections are in agreement with a previous activation measurement performed at Forschungszentrum Karlsruhe by Marganiec et al., once their data has been re-normalised to account for an update in the reference cross section used in that experiment.
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The neutron capture cross sections of several unstable nuclides acting as branching points in the s process are crucial for stellar nucleosynthesis studies. The unstable ^{171}Tm (t_{1/2}=1.92 yr) is part of the branching around mass Aâ¼170 but its neutron capture cross section as a function of the neutron energy is not known to date. In this work, following the production for the first time of more than 5 mg of ^{171}Tm at the high-flux reactor Institut Laue-Langevin in France, a sample was produced at the Paul Scherrer Institute in Switzerland. Two complementary experiments were carried out at the neutron time-of-flight facility (n_TOF) at CERN in Switzerland and at the SARAF liquid lithium target facility at Soreq Nuclear Research Center in Israel by time of flight and activation, respectively. The result of the time-of-flight experiment consists of the first ever set of resonance parameters and the corresponding average resonance parameters, allowing us to make an estimation of the Maxwellian-averaged cross sections (MACS) by extrapolation. The activation measurement provides a direct and more precise measurement of the MACS at 30 keV: 384(40) mb, with which the estimation from the n_TOF data agree at the limit of 1 standard deviation. This value is 2.6 times lower than the JEFF-3.3 and ENDF/B-VIII evaluations, 25% lower than that of the Bao et al. compilation, and 1.6 times larger than the value recommended in the KADoNiS (v1) database, based on the only previous experiment. Our result affects the nucleosynthesis at the Aâ¼170 branching, namely, the ^{171}Yb abundance increases in the material lost by asymptotic giant branch stars, providing a better match to the available pre-solar SiC grain measurements compared to the calculations based on the current JEFF-3.3 model-based evaluation.
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We report on the measurement of the ^{7}Be(n,p)^{7}Li cross section from thermal to approximately 325 keV neutron energy, performed in the high-flux experimental area (EAR2) of the n_TOF facility at CERN. This reaction plays a key role in the lithium yield of the big bang nucleosynthesis (BBN) for standard cosmology. The only two previous time-of-flight measurements performed on this reaction did not cover the energy window of interest for BBN, and they showed a large discrepancy between each other. The measurement was performed with a Si telescope and a high-purity sample produced by implantation of a ^{7}Be ion beam at the ISOLDE facility at CERN. While a significantly higher cross section is found at low energy, relative to current evaluations, in the region of BBN interest, the present results are consistent with the values inferred from the time-reversal ^{7}Li(p,n)^{7}Be reaction, thus yielding only a relatively minor improvement on the so-called cosmological lithium problem. The relevance of these results on the near-threshold neutron production in the p+^{7}Li reaction is also discussed.
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INTRODUCTION: The correct oral treatment of pigs in groups is a demanding procedure. Prescriptions of medicated feed for groups larger than 20 pigs have to be made on official forms submitted to veterinary authorities. In this work, we evaluated 1'126 such forms for the years 2010-2011 to calculate the therapeutic intensity for piglets and fatteners at farm level in the canton of Lucerne. This analysis shows that essential data were often difficult to obtain and that the provided information did not always allow for plausible intensity calculations. In total, 654 and 424 kg of antimicrobials were prescribed during the 2 years under investigation. For the years 2010 and 2011, the calculated median intensities were 43.5 and 32.5 treated animals per 1'000 individuals per day (PIDvet) for piglets and 75.9 and 64.8 for fatteners. PIDvet for the whole populations of piglets and fatteners treated with medicated feed delivered from feed mills were 37.51 resp. 84.44 in the year 2011.
INTRODUCTION: L'administration orale d'antibiotiques à des groupes d'animaux est exigeante. Toute prescription destinée à plus de 20 porcs à traiter doit, légalement, être faite au moyen d'un formulaire d'ordonnance officiel. Dans le présent article, on étudie l'intensité des traitements chez des porcelets et des porcs d'engraissement dans des exploitations du canton de Lucerne durant les années 20102011 sur la base de 1'126 formulaires. Cette analyse montre que des données importantes pour le calcul sont souvent difficiles à obtenir et que des calculs plausibles sont partiellement impossibles. Au total 654 respectivement 424 kg d'antibiotiques ont été prescrits durant ces deux ans. L'intensité médiane des traitements pour 2010 et 2011 s'élevait à 43.5 et 32.5 animaux en traitement pour 1000 individus à une date donnée (PIDvet) pour les porcelets et à 75.9 et 64.8 pour les porcs d'engraissement. Pour l'ensemble de la population de porcelets et de porcs d'engraissement, des valeurs de PIDvet de 37.51 respectivement 84.44 pour l'application en 2011 d'aliments médicamenteux produits par les moulins agricoles, ont été calculées.
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Anti-Infecciosos/administração & dosagem , Doenças dos Suínos/tratamento farmacológico , Drogas Veterinárias/administração & dosagem , Ração Animal , Animais , Suínos , Doenças dos Suínos/prevenção & controleRESUMO
The energy-dependent cross section of the ^{7}Be(n,α)^{4}He reaction, of interest for the so-called cosmological lithium problem in big bang nucleosynthesis, has been measured for the first time from 10 meV to 10 keV neutron energy. The challenges posed by the short half-life of ^{7}Be and by the low reaction cross section have been overcome at n_TOF thanks to an unprecedented combination of the extremely high luminosity and good resolution of the neutron beam in the new experimental area (EAR2) of the n_TOF facility at CERN, the availability of a sufficient amount of chemically pure ^{7}Be, and a specifically designed experimental setup. Coincidences between the two alpha particles have been recorded in two Si-^{7}Be-Si arrays placed directly in the neutron beam. The present results are consistent, at thermal neutron energy, with the only previous measurement performed in the 1960s at a nuclear reactor. The energy dependence reported here clearly indicates the inadequacy of the cross section estimates currently used in BBN calculations. Although new measurements at higher neutron energy may still be needed, the n_TOF results hint at a minor role of this reaction in BBN, leaving the long-standing cosmological lithium problem unsolved.
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The 63Ni(n,γ) cross section has been measured for the first time at the neutron time-of-flight facility n_TOF at CERN from thermal neutron energies up to 200 keV. In total, capture kernels of 12 (new) resonances were determined. Maxwellian averaged cross sections were calculated for thermal energies from kT=5-100 keV with uncertainties around 20%. Stellar model calculations for a 25Mâ star show that the new data have a significant effect on the s-process production of 63Cu, 64Ni, and 64Zn in massive stars, allowing stronger constraints on the Cu yields from explosive nucleosynthesis in the subsequent supernova.
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OBJECTIVES: To evaluate whether induced dental pain leads to quantitative changes in brain metabolites within the left insular cortex after stimulation of the right maxillary canine and to examine whether these metabolic changes and the subjective pain intensity perception correlate. METHODS: Ten male volunteers were included in the pain group and compared with a control group of 10 other healthy volunteers. The pain group received a total of 87-92 electrically induced pain stimuli over 15 min to the right maxillary canine tooth. Contemporaneously, they evaluated the subjective pain intensity of every stimulus using an analogue scale. Neurotransmitter changes within the left insular cortex were evaluated by MR spectroscopy. RESULTS: Significant metabolic changes in glutamine (+55.1%), glutamine/glutamate (+16.4%) and myo-inositol (-9.7%) were documented during pain stimulation. Furthermore, there was a significant negative correlation between the subjective pain intensity perception and the metabolic levels of Glx, Gln, glutamate and N-acetyl aspartate. CONCLUSION: The insular cortex is a metabolically active region in the processing of acute dental pain. Induced dental pain leads to quantitative changes in brain metabolites within the left insular cortex resulting in significant alterations in metabolites. Negative correlation between subjective pain intensity rating and specific metabolites could be observed.
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Espectroscopia de Ressonância Magnética/métodos , Dor/patologia , Nervo Trigêmeo/patologia , Adulto , Ácido Aspártico/análogos & derivados , Ácido Aspártico/metabolismo , Córtex Cerebral/patologia , Eletrodos , Feminino , Ácido Glutâmico/metabolismo , Glutamina/metabolismo , Humanos , Inositol/metabolismo , Masculino , Pessoa de Meia-Idade , Modelos Anatômicos , Neurotransmissores/metabolismo , Estudos Prospectivos , Prótons , Doenças Dentárias/patologiaRESUMO
For identical diagnoses in the trigeminal innervation territory, individual differences have been clinically observed among the symptoms reported, such as dysesthesia and pain. Different subjective perceptions of unpleasantness and pain intensity may have different cortical substrates. The aim of this study was to identify brain areas in which activation depends on the subjective perception (intensity and unpleasantness) of electric dental stimulation. Electrical stimuli of increasing intensity were applied to maxillary canines in 14 healthy volunteers. Ratings for stimulus intensity and unpleasantness perceived across the stimulation session were reported postscan on 11-point numerical scales. The rating values were then included as covariates in the functional magnetic resonance imaging (fMRI) group analysis. Interindividual differences of intensity ratings were reflected in differential activity of the following brain areas: superior parietal lobule, superior temporal gyrus/anterior insula, inferior and middle temporal gyrus, lingual gyrus, anterior cingulate, and caudate nucleus. Differences related to unpleasantness ratings were reflected in the lingual gyrus. In conclusion, differences of perceived intensity between individuals are reflected in the differential activity of a set of brain areas distinct from those regions, reflecting rating differences of unpleasantness.
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Mapeamento Encefálico , Córtex Cerebral/fisiologia , Dente Canino/inervação , Vias Neurais/fisiologia , Sensação/fisiologia , Adulto , Estimulação Elétrica , Feminino , Humanos , Masculino , Maxila , Pessoa de Meia-Idade , Valores de Referência , Nervo Trigêmeo/fisiologiaRESUMO
A novel, ultrasound based approach for the dynamic stimulation and promotion of tissue healing processes employing surface acoustic waves (SAW) on a chip is presented for the example of osteoblast-like SaOs-2 cells. In our investigations, we directly irradiate cells with SAW on a SiO2 covered piezoelectric LiNbO3 substrate. Observing the temporal evolution of cell growth and migration and comparing non-irradiated to irradiated areas on the chip, we find that the SAW-treated cells exhibit a significantly increased migration as compared to the control samples. Apart from quantifying our experimental findings on the cell migration stimulation, we also demonstrate the full bio compatibility and bio functionality of our SAW technique by using LDH assays. We safely exclude parasitic side effects such as a SAW related increased substrate temperature or nutrient flow by thoroughly monitoring the temperature and the flow field using infrared microscopy and micro particle image velocimetry. Our results show that the SAW induced dynamic mechanical and electrical stimulation obviously directly promotes the cell growth. We conclude that this stimulation method offers a powerful platform for future medical treatment, e.g. being implemented as a implantable biochip with wireless extra-corporal power supply to treat deeper tissue.
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Técnicas de Cultura de Células , Movimento Celular , Ondas Ultrassônicas , Cicatrização , Linhagem Celular Tumoral , Estimulação Elétrica , Desenho de Equipamento , Humanos , Nióbio/química , Óxidos/química , Dióxido de Silício/química , VibraçãoRESUMO
The LHC will require an extremely powerful and unprecedented collimation system. As approximately 30% of the LHC beam is lost in the cleaning insertions, these will become some of the most radioactive locations around the entire LHC ring. Thus, remanent dose rates to be expected during later repair or maintenance interventions must be considered in the design phase itself. As a consequence, the beam cleaning insertions form a unique test bed for a recently developed approach to calculate remanent dose rates. A set of simulations, different in complexity, is used in order to evaluate methods for the estimation of remanent dose rates. The scope, as well as the restrictions, of the omega-factor method are shown and compared with the explicit simulation approach. The latter is then used to calculate remanent dose rates in the beam cleaning insertions. Furthermore, a detailed example for maintenance dose planning is given.
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Arquitetura de Instituições de Saúde/métodos , Exposição Ocupacional/análise , Aceleradores de Partículas/instrumentação , Monitoramento de Radiação/métodos , Proteção Radiológica/instrumentação , Medição de Risco/métodos , Simulação por Computador , Desenho Assistido por Computador , Relação Dose-Resposta à Radiação , Desenho de Equipamento , Análise de Falha de Equipamento , Transferência Linear de Energia , Modelos Teóricos , Nêutrons , Prótons , Doses de Radiação , Proteção Radiológica/métodos , Fatores de Risco , SuíçaRESUMO
Samples of materials which will be used in the LHC machine for shielding and construction components were irradiated in the stray radiation field of the CERN-EU high-energy reference field facility. After irradiation, the specific activities induced in the various samples were analysed with a high-precision gamma spectrometer at various cooling times, allowing identification of isotopes with a wide range of half-lives. Furthermore, the irradiation experiment was simulated in detail with the FLUKA Monte Carlo code. A comparison of measured and calculated specific activities shows good agreement, supporting the use of FLUKA for estimating the level of induced activity in the LHC.
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Materiais de Construção/análise , Transferência Linear de Energia , Modelos Teóricos , Proteção Radiológica/instrumentação , Proteção Radiológica/métodos , Radioisótopos/análise , Radiometria/métodos , Benchmarking/métodos , Simulação por Computador , Materiais de Construção/normas , Teste de Materiais/métodos , Teste de Materiais/normas , Método de Monte Carlo , Aceleradores de Partículas/instrumentação , Doses de Radiação , Proteção Radiológica/normas , Radiometria/instrumentação , Radiometria/normas , Reprodutibilidade dos Testes , Espalhamento de Radiação , Sensibilidade e Especificidade , SuíçaRESUMO
A new method to estimate remanent dose rates, to be used with the Monte Carlo code FLUKA, was benchmarked against measurements from an experiment that was performed at the CERN-EU high-energy reference field facility. An extensive collection of samples of different materials were placed downstream of, and laterally to, a copper target, intercepting a positively charged mixed hadron beam with a momentum of 120 GeV c(-1). Emphasis was put on the reduction of uncertainties by taking measures such as careful monitoring of the irradiation parameters, using different instruments to measure dose rates, adopting detailed elemental analyses of the irradiated materials and making detailed simulations of the irradiation experiment. The measured and calculated dose rates are in good agreement.
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Materiais de Construção/análise , Transferência Linear de Energia , Modelos Teóricos , Proteção Radiológica/instrumentação , Proteção Radiológica/métodos , Radioisótopos/análise , Radiometria/métodos , Benchmarking/métodos , Simulação por Computador , Materiais de Construção/normas , Teste de Materiais/métodos , Teste de Materiais/normas , Método de Monte Carlo , Aceleradores de Partículas/instrumentação , Doses de Radiação , Proteção Radiológica/normas , Radiometria/instrumentação , Radiometria/normas , Reprodutibilidade dos Testes , Espalhamento de Radiação , Sensibilidade e Especificidade , SuíçaRESUMO
Local anesthesia has made dental treatment more comfortable since 1884, but little is known about associated brain mechanisms. Functional magnetic resonance imaging is a modern neuroimaging tool widely used for investigating human brain activity related to sensory perceptions, including pain. Most brain regions that respond to experimental noxious stimuli have recently been found to react not only to nociception alone, but also to visual, auditory, and other stimuli. Thus, presumed functional attributions have come under scrutiny regarding selective pain processing in the brain. Evidently, innovative approaches are warranted to identify cerebral regions that are nociceptive specific. In this study, we aimed at circumventing known methodological confounders by applying a novel paradigm in 14 volunteers: rather than varying the intensity and thus the salience of painful stimuli, we applied repetitive noxious dental stimuli at constant intensity to the left mandibular canine. During the functional magnetic resonance imaging paradigm, we suppressed the nociceptive barrage by a mental nerve block. Brain activity before and after injection of 4% articaine was compared intraindividually on a group level. Dental pain extinction was observed to correspond to activity reduction in a discrete region of the left posterior insular cortex. These results confirm previous reports demonstrating that direct electrical stimulation of this brain region-but not of others-evokes bodily pain sensations. Hence, our investigation adds further evidence to the notion that the posterior insula plays a unique role in nociceptive processing.
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Encéfalo/fisiopatologia , Odontalgia/tratamento farmacológico , Adulto , Anestésicos Locais/administração & dosagem , Carticaína/administração & dosagem , Cerebelo/fisiopatologia , Córtex Cerebral/fisiopatologia , Queixo/inervação , Dente Canino/efeitos dos fármacos , Dente Canino/inervação , Estimulação Elétrica , Giro do Cíngulo/fisiopatologia , Hipocampo/fisiopatologia , Humanos , Imageamento por Ressonância Magnética/métodos , Masculino , Bloqueio Nervoso/métodos , Vias Neurais/fisiopatologia , Nociceptividade/efeitos dos fármacos , Nociceptividade/fisiologia , Dor/fisiopatologia , Lobo Parietal/fisiopatologia , Córtex Pré-Frontal/fisiopatologia , Lobo Temporal/fisiopatologia , Tálamo/fisiopatologia , Odontalgia/fisiopatologia , Córtex Visual/fisiopatologia , Adulto JovemRESUMO
A chemiluminescence assay was developed based on the interaction between antibodies binding to the surface of living brain cells in culture and macrophages. Such interaction leads to production of reactive oxygen radicals which can be measured by a chemiluminescence assay. This assay was used to detect anti brain antibodies in serum samples from humans with various neurological diseases. Such antibody activity was found in a high proportion of these patients. Subsequent experiments with purified IgG fractions and corresponding F(ab')2 fragments showed that the observed reactions were highly specific. It was concluded that the chemiluminescence assay is a sensitive and useful technique to detect autoantibodies in neurological diseases.
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Anticorpos/sangue , Antígenos de Superfície/imunologia , Encéfalo/imunologia , Animais , Células Cultivadas , Cães , Humanos , Medições Luminescentes , Camundongos , Doenças do Sistema Nervoso/imunologiaRESUMO
Relative activities of a series of corticotrophin analogues have been measured by means of five different bioassays using the rat. Similarities in the relative potencies of various ACTH analogues determined using lipolysis or steroidogenesis in vivo and for the lipolytic and steroidogenic responses of fat pads and adrenal slices in vitro emerged and support the concept of a close structural relationship between the ACTH receptors in adipose and adrenal tissues in the rat. Potencies based on the steroidogenic response of isolated adrenal cells, adrenal slices or in-vivo experiments differed markedly from each other. Inactivation of peptides did not occur in the isolated cell assay, so it is likely that this assay estimates potency at the receptor level. A number of arguments suggest that the difference between the isolated cell assay and the other steroidogenic assays lies solely in the effects of peptide inactivation in the latter, and this allows the relative metabolic stabilities for the peptide analogues in these assays to be calculated. In this way it can be shown that: (1) Replacement of L-Ser by D-Ser in amino acid position 1 markedly increases the metabolic stability of the peptide and has only a slight effect on receptor properties. (2) Shortening at the NH2-terminus reduces the activity of peptides at the receptor level by several orders of magnitude, but increases their relative metabolic stability. (3) Introduction of amide groups at the CO2H-terminus markedly increases receptor potency of (1-16), (1-17) and (1-18) ACTH without affecting their metabolic stability in vivo. However, amidation of the CO2H-terminus does have a large effect on metabolic stability in the adrenal slice assay. (4) Replacement of Arg by Lys in positions 17 and 18 of (1-18) ACTH increases potency at the receptor level (adrenal cells) but has little effect on metabolic stability. The comparison of potencies obtained in the various assays, therefore, throws light on the significance of each assay. In addition, the effects of structural modification of analogues can be separately evaluated with respect to the metabolic stability of a peptide and its potency at the receptor level.
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Glândulas Suprarrenais/efeitos dos fármacos , Hormônio Adrenocorticotrópico/análogos & derivados , Cosintropina/análogos & derivados , Cosintropina/farmacologia , Corticosteroides/sangue , Animais , Bioensaio/métodos , Ácidos Graxos não Esterificados/sangue , Técnicas In Vitro , Masculino , Ratos , Relação Estrutura-AtividadeRESUMO
Proximal selective vagotomy (PSV) is an effective, definitive therapy for peptic ulcer disease of the duodenum. Long-term studies have shown that ulcer recurrence occurs in less than 10% of patients if the operation is performed by an experienced surgeon. Since PSV does not influence gastric emptying, side effects such as diarrhea, gastric stasis or the dumping syndrome are rare. Due to this favorable experience, PSV is our preferred technique for the laparoscopic approach to peptic ulcer disease. We have performed this operation in 13 patients. Indications were chronic duodenal ulceration unresponsive to medical therapy, chronic duodenal ulceration combined with reflux esophagitis, and reflux esophagitis due to gastric acid hypersecretion. In patients with reflux esophagitis PSV was performed in addition to an antireflux procedure. Laparoscopic PSV can be performed more accurately than the open procedure since it allows for better visualization with less possibility of missing small vagal connections to the parietal cells such as the 'criminal nerve'. The median duration of operation was 3 hours. There were no serious peri- or postoperative complications. The median time of postoperative hospital stay was 3 days. During the median follow-up of 27 months no recurrence of duodenal or esophageal ulceration was encountered and none of the patients complained of epigastric pain, diarrhea or dumping symptoms.
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Úlcera Duodenal/cirurgia , Esofagite Péptica/cirurgia , Laparoscópios , Vagotomia Gástrica Proximal/instrumentação , Adulto , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Complicações Pós-Operatórias/etiologia , Resultado do TratamentoRESUMO
The course of pseudo-aneurysm of the axillary artery, rarely occurring after blunt trauma of the shoulder, is analysed. Own experience is reported, the literature is reviewed. A high index of suspicion is necessary to recognise and repair this serious vascular injury in time in order to avoid permanent brachial plexus deficiency.
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Falso Aneurisma/cirurgia , Artéria Axilar/lesões , Luxação do Ombro/cirurgia , Idoso , Falso Aneurisma/diagnóstico por imagem , Artrografia , Artéria Axilar/diagnóstico por imagem , Artéria Axilar/cirurgia , Humanos , Masculino , Microcirurgia , Veia Safena/transplante , Luxação do Ombro/diagnóstico por imagem , Tomografia Computadorizada por Raios XRESUMO
This report describes the findings in a four-year-old Toggenburg goat with demodicosis. The skin had multifocal nodules, which were approximately 5 mm in diameter and contained thick yellow exsudate. Microscopic examination of the exsudate revealed numerous Demodex caprae. The goat was clipped and treated topically every five to seven days for a total of 12 treatments with a 1:100 dilution of amitraz (Ectodex, Hoechst Roussel Vet). The treatment resulted in a marked decrease in the number of skin nodules. However, new nodules appeared after treatment was discontinued and complete clinical cure was not achieved.