RESUMO
The relaxation behavior of two lignins (Alcell organosolv, OSL, and hydroxypropyl modified Kraft, ML) and bio-based thermoplastic polyurethane (TPU) blends have been studied by Differential Scanning Calorimetry (DSC), Dynamic-Mechanical Analysis (DMA) and Dielectric Relaxation Spectroscopy (DRS). The effect of blending on the glass and local relaxation processes as a function of composition, frequency, and temperature has been assessed. The dielectric spectra were resolved into dipolar relaxations as well as conductive processes for differing blend compositions. Characteristic relaxation times, activation energies and dielectric relaxation strengths of lignin/xTPU blends were also investigated. It was found that blending suppresses the α-relaxation process of the blends compared to virgin TPU. On the other hand, while the position of the ß-relaxation was not influenced by blending, a reduction of the activation energies, Ea, of this process was observed in the lignin/xTPU blends. Finally, changes are observed in the conductivity behavior of both blends, with conductivity processes more favorable for the OSL/xTPU blends.
RESUMO
Medical grade ultra high molecular weight polyethylene (UHMWPE) of two molecular weights has been gamma irradiated in air to give received doses of 3.5 and 10 Mrad and aged in air for 25 months. Differential scanning calorimetry and wide and small angle X-ray diffraction (WAX and SAX) techniques and transmission electron microscopy have been used to characterize the materials. Polymer from an orthopaedic component, retrieved 10 years after implantation, has been subjected to the same analytical programme. The X-ray diffraction data shows that following irradiation two events occur with time, first a crystal refinement process, indicated by pronounced sharpening of the SAX peak, and secondly growth of a new crystal population of reduced lamellae thickness compared to the original crystal structures, shown by the development of a bimodal SAX pattern. Following irradiation crystallinity increases with time and this second crystal population makes a significant contribution to that increase. The retrieved component shows full development of these processes. It is considered that these crystallographic changes with time are responsible for the observed time dependent changes in the mechanical properties of air irradiated UHMWPE.
Assuntos
Peso Molecular , Polietilenos/química , Materiais Biocompatíveis , Varredura Diferencial de Calorimetria , Cristalização , Humanos , Teste de Materiais , Microscopia Eletrônica de Transmissão , Polímeros/química , Falha de Prótese , Propriedades de Superfície , Temperatura , Resistência à Tração , Fatores de Tempo , Difração de Raios XRESUMO
REASONS FOR PERFORMING STUDY: While imprint training procedures have been promoted in popular magazines, they have received limited scientific investigation. OBJECTIVES: To determine the effects of a neonatal imprint training procedure on 6-month-old foals and to determine if any one session had a greater effect than others. METHODS: Foals (n = 131) were divided into the following treatments: no imprint training, imprint training at birth, 12, 24 and 48 h after birth or imprint training only at birth, 12, 24, 48, or 72 h after birth. Foals then received minimal human handling until they were tested at 6 months. RESULTS: During training, time to complete exposure to the stimulus was significant for only 2 of 6 stimuli. Percentage change in baseline heart rate was significant for only 2 of 10 stimuli. These 4 effects were randomly spread across treatments. CONCLUSIONS: Neither the number of imprint training sessions (0, 1, or 4) nor the timing of imprint training sessions (none, birth, 12, 24, 48, or 72 h after birth) influenced the foal's behaviour at 6 months of age. POTENTIAL CLINICAL RELEVANCE: In this study, imprint training did not result in better behaved, less reactive foals.
Assuntos
Animais Recém-Nascidos/psicologia , Comportamento Animal , Cavalos/psicologia , Vínculo Humano-Animal , Fixação Psicológica Instintiva , Fatores Etários , Criação de Animais Domésticos/métodos , Animais , Feminino , Manobra Psicológica , Humanos , Masculino , Distribuição Aleatória , Socialização , Fatores de TempoRESUMO
Capgras' syndrome, one form of the delusional misidentification syndromes, is described. Three patients with the syndrome are reported. The first had a right cerebral infarction, the second had nephrotic syndrome secondary to severe pre-eclampsia in the puerperium, and the third had uncontrolled diabetes mellitus with dementia. Evidence is reviewed regarding an organic aetiology for Capgras' syndrome. We conclude that, when the syndrome is present, a thorough search for organic disorder should be made.
Assuntos
Síndrome de Capgras/etiologia , Infarto Cerebral/psicologia , Diabetes Mellitus Tipo 1/psicologia , Síndrome Nefrótica/psicologia , Transtornos Puerperais/psicologia , Adulto , Idoso , Infarto Cerebral/complicações , Demência/complicações , Diabetes Mellitus Tipo 1/complicações , Feminino , Humanos , Síndrome Nefrótica/complicações , GravidezRESUMO
An out-patient alcohol detoxification service based in a psychiatric emergency clinic is described. Of 173 patients referred during the first year, 76 (44%) were accepted for the programme; 60 (79%) of these successfully completed detoxification with no medical complications. Compared with previous years, during the year of operation of the service there was a 50% fall in the number of in-patient admissions for detoxification to the local hospital. We conclude that a structured out-patient detoxification programme is safe and effective, and may obviate the need for many patients to be admitted, freeing psychiatric beds for other uses.
Assuntos
Alcoolismo/terapia , Assistência Ambulatorial , Adolescente , Adulto , Idoso , Aconselhamento , Diazepam/uso terapêutico , Serviço Hospitalar de Emergência , Feminino , Humanos , Londres , Masculino , Pessoa de Meia-Idade , Prognóstico , Unidade Hospitalar de PsiquiatriaRESUMO
A manic-depressive young woman received mild brain damage from anoxia after attempting suicide by hanging. The case conference was held to elucidate whether her subsequent symptoms were functional or organic, and what courses of treatment should be tried in this very refractory case.
Assuntos
Transtorno Bipolar/diagnóstico , Dano Encefálico Crônico/diagnóstico , Hipóxia Encefálica/diagnóstico , Transtornos Neurocognitivos/diagnóstico , Atividades Cotidianas/psicologia , Adolescente , Transtorno Bipolar/genética , Transtorno Bipolar/psicologia , Dano Encefálico Crônico/complicações , Dano Encefálico Crônico/psicologia , Terapia Combinada , Diagnóstico Diferencial , Epilepsia do Lobo Temporal/complicações , Epilepsia do Lobo Temporal/diagnóstico , Epilepsia do Lobo Temporal/psicologia , Feminino , Humanos , Hipóxia Encefálica/complicações , Hipóxia Encefálica/psicologia , Transtornos Neurocognitivos/psicologia , Exame Neurológico , Testes Neuropsicológicos , Tentativa de Suicídio/psicologiaRESUMO
Disturbances in autonomic control during myocardial ischemia may contribute significantly to the development of malignant cardiac arrhythmias. Therefore acute ischemia was induced in 29 mongrel dogs with healed myocardial infarctions during an exercise test. Seventeen animals developed ventricular fibrillation (susceptible, S), whereas 12 dogs did not (resistant, R). Before the exercise plus ischemia test a coronary occlusion was made at rest. The amplitude of respiratory sinus arrhythmia (0.24- to 1.04-Hz component of R-R interval fluctuation) was used as an index of cardiac vagal tone. Acute ischemia elicited a significantly larger heart rate increase in susceptible animals (S: control 115.6 +/- 0.8, occlusion 176.4 +/- 8.2 beats/min vs. R: control 114.6 +/- 8.9, occlusion 145.7 +/- 7.5 beats/min). Accompanying the heart rate increase were significantly greater reductions in the cardiac vagal tone index in the susceptible animals. (S: control 6.4 +/- 0.3, occlusion 2.2 +/- 0.6 ln ms2 vs. R: control 6.6 +/- 0.4, occlusion 5.1 +/- 0.5 ln ms2). beta-Adrenergic receptor blockade reduced the heart rate increases but exacerbated the reductions in the cardiac vagal tone index. These data suggest that coronary artery occlusion elicits a significantly greater increase in sympathetic activity coupled with a greater reduction in parasympathetic activity in animals subsequently shown to be susceptible to ventricular fibrillation.