Rats given medial frontal lesions on Postnatal Day 1 or Day 10 were trained on the Morris water task on Days 19–21 or Days 56–58. The operated groups were equally impaired at the water task on Days 19–21, but the Day 10 rats had recovered by 56 days. Dendritic arborization and spine density were analyzed in parietal layer II–III pyramidal cells. At Day 60, but not at Day 22, the Day 10 animals had more dendritic spines per unit dendritic length than did the controls or Day 1 rats. Thus, there was functional recovery rather than sparing after frontal lesions at 10 days, and the recovery was correlated with an increase in dendritic spines. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
The purpose of this study was to determine the long-term results of allogeneic bone marrow transplantation for chronic myeloid leukemia. A retrospective analysis was carried out of the outcome of 373 consecutive transplants performed at 38 European institutions between 1980 and 1988 and reported to the registry of the European Group for Blood and Marrow Transplantation. All transplants were carried out for first chronic phase of chronic myelogenous leukemia using unmanipulated marow cells from HLA-identical sibling donors. The probability of survival and leukemia-free survival at 8 years were 54% (95% CI: 49-59) and 47% (95% CI: 41-52) respectively. The probabilities of developing acute GVHD (II-IV) at 100 days and chronic GVHD at 4 years after transplant were 47% (95% CI: 41-53) and 52% (95% CI: 46-58) respectively. The probabilities of transplant-related mortality and leukemic relapse 8 years after BMT were 41% (95% CI: 36-48) and 19% (95% CI: 14-25), respectively. Transplant within 12 months of diagnosis was associated with reduced transplant-related mortality (34 vs 45%, P = 0.013) and resulted in improved leukemia-free survival (52 vs 44%, P = 0.03). The probability of relapse was significantly reduced in patients who developed chronic GVHD (RR = 0.33, P = 0.004). The probability of relapse occurring more than 2 years after transplant was increased more than five-fold in patients transplanted from a male donor (RR = 5.5, P = 0.006). Sixty-seven patients in hematologic remission were studied for residual disease by two-step RT/PCR for BCR-ABL mRNA and 61 (91%) tested negative. We conclude that bone marrow transplantation can induce long-term survival in approximately one-half of CML patients; the majority of survivors have no evidence of residual leukemia cells when studied by molecular techniques. The probability of late relapse is increased with use of a male donor. 相似文献
Porous NiTi shape memory alloy (SMA) is a novel biomedical material used for human hard tissue implant .The influence of elemental titanium powder characteristics such as powder morphology, particle size and specific surface area( SSA) on the minimal ignition temperature ,combustion temperature and final product of porous Ni-Ti SMA fabricated by combustion synthesis method was investigated in this paper by scanning electron microscopy (SEM) and laser diffraction.The preliminary data indicated that the titanium powder characteristics had a strong effect on combustion synthesis of porous NiTi SMA. 相似文献
For timber the tensile stress perpendicular to the grain is a critical type of stress. The influence of long-term loading, temperature and climate changes upon the tensile strength perpendicular to the grain of timber is shown. The results prove that the greatest loss of strength happened after long-term outdoors loading. While storing under alternating climate conditions, great crepp strains appeared, and it is to be presumed that the damages of wooden components which fail across the grain are less a problem of “tensile stress perpendicular to the grain” than a problem of “strain under tension perpendicular to the grain”. 相似文献
Hebb's principal theoretical propositions, the cell assembly and the nature of synaptic change, were generated at a time when the focus of work in behavioural neuroscience was directed at understanding issues such as the principles governing the behaviour of animals in neuropsychological studies of learning and memory and the role of drives in the control of behaviours like sex and feeding and drinking. It was not until attention shifted to understanding the neural underpinnings of learning and memory that Hebb's propositions had an impact on behavioural neuroscience as they provided a simple, and testable, mechanism for synaptic plasticity observed both in learning and in other forms of experience-dependent neural change. But much of the field remains interested in other issues such as sensation and perception, motivation, attention, and so on, and to date, Hebb's propositions have had little impact. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
The liposomal formulation of amphotericin B (AmBisome) greatly reduces the acute and chronic side effects of the parent drug. The present study describes the pharmacokinetic characteristics of AmBisome applied to 10 patients at a dose of 2.8 to 3.0 mg/kg of body weight and compares them to the pharmacokinetics observed in 6 patients treated with amphotericin B deoxycholate at the standard dose of 1.0 mg/kg. Interpatient variabilities of amphotericin B peak concentrations (Cmax) and areas under concentration-time curves (AUC) were 8- to 10-fold greater for patients treated with AmBisome than for patients treated with amphotericin B deoxycholate. At the threefold greater dose of AmBisome, median Cmaxs were 8.4-fold higher (14.4 versus 1.7 microg/ml) and median AUCs exceeded those observed with amphotericin B deoxycholate by 9-fold. This was in part explained by a 5.7-fold lower volume of distribution (0.42 liters/kg) in AmBisome-treated patients. The elimination of amphotericin B from serum was biphasic for both formulations. However, the apparent half-life of elimination was twofold shorter for AmBisome (P = 0.03). Neither hemodialysis nor hemofiltration had a significant impact on AmBisome pharmacokinetics as analyzed in one patient. In conclusion, the liposomal formulation of amphotericin B significantly (P = 0.001) reduces the volume of drug distribution, thereby allowing for greater drug concentrations in serum. The low toxicity of AmBisome therefore cannot readily be explained by its serum pharmacokinetics. 相似文献
In most countries of the world asphalt pavement of road networks represents the biggest single investment in the transportation system. In Canada, asphalt pavement built over the past decade is worth more than 70 billion dollars (in 1984 dollars). In order to maintain the current road network at the present level of service and prevent it from further deterioration, over 6 billion dollars is needed anually.
Traditionally, asphalt overlays are widely used to rehabilitate existing deteriorated pavements. Unfortunately the new overlays have been observed to fail in a relatively short time. Thus the investment in overlays is lost.
Recent research based on the concept of relative rigidity has indicated that the rapid deterioration of new asphalt overlays is directly related to current construction equipment. It has been shown analytically and experimentally that steel rollers used in compacting the asphalt layer will result in surface cracks during construction. Traffic and environmental influences will accelerate the failure of the new layer.
This paper presents the results of a testing programme evaluating the engineering properties of asphalt slabs compacted by a new method using a compactor termed AMIR. The results showed that the AMIR compactor will prevent the formation of constitution cracks resulting in an increase of indirect tensile strength of 10% and an increase of direct tensile strength of up to 60% when compared to steel roller compacted asphalt slabs. 相似文献
BACKGROUND: Transplantation of blood or bone-marrow stem cells is the treatment of choice for selected patients with chronic myeloid leukaemia (CML). Transplantation is used with increasing frequency and success, but remains associated with substantial risks of morbidity and mortality. Other treatments with satisfactory short-term outcome are available. For appropriate counselling of patients, a rapid and simple way to assess risk is needed. METHODS: Data from 3142 patients (1873 [60%] male, 1269 [40%] female; mean age 34 years, range <1-60 years) treated with allogeneic blood or marrow transplants for CML between 1989 and 1997, reported to the European Group for Blood and Marrow Transplantation (EBMT), were used to develop and test a simple risk score based on previously reported major pretransplant risk factors: histocompatibility, stage of disease at time of transplantation, age and sex of donor and recipient, and time from diagnosis to transplantation. We analysed probabilities of survival, leukaemia-free survival, transplant-related mortality, and relapse incidence with respect to these risk factors. FINDINGS: At the time of analysis, 1922 (61%) of the 3142 patients were alive-1567 (65%) of those with HLA-identical sibling donors and 417 (57%) of those with unrelated donors. 1682 (54%) were alive without relapse. 1220 (39%) patients had died, 1013 (83%) of transplant-related causes, 207 (17%) of relapse. 447 (14%) patients had relapsed. The final scoring system was highly predictive for leukaemia-free survival, survival and transplant-related mortality. Survival at 5 years was 72%, 70%, 62%, 48%, 40%, 18%, and 22% for patients with scores 0, 1, 2, 3, 4, 5, and 6, respectively. Risk of transplant-related mortality was 20%, 23%, 31%, 46%, 51%, 71%, and 73%. Data showed the same trends for HLA-identical sibling transplants and unrelated transplants for transplants done in 1989-93 and 1994-96. INTERPRETATION: Pretransplant risk factors are cumulative for individual patients with CML having blood or marrow transplantation. A simple system based on five main factors gives adequate risk assessment for counselling of patients and taking decisions. 相似文献
Multi- and hyperspectral imaging and data analysis has been investigated in the last decades in the context of various fields of application like remote sensing or microscopic spectroscopy. However, recent developments in sensor technology and a growing number of application areas require a more generic view on data analysis, that clearly expands the current, domain-specific approaches. In this context, we address the problem of interactive exploration of multi- and hyperspectral data, consisting of (semi-)automatic data analysis and scientific visualization in a comprehensive fashion. In this paper, we propose an approach that enables a generic interactive exploration and easy segmentation of multi- and hyperspectral data, based on characterizing spectra of an individual dataset, the so-called endmembers. Using the concepts of existing endmember extraction algorithms, we derive a visual analysis system, where the characteristic spectra initially identified serve as input to interactively tailor a problem-specific visual analysis by means of visual exploration. An optional outlier detection improves the robustness of the endmember detection and analysis. An adequate system feedback of the costly unmixing procedure for the spectral data with respect to the current set of endmembers is ensured by a novel technique for progressive unmixing and view update which is applied at user modification. The progressive unmixing is based on an efficient prediction scheme applied to previous unmixing results. We present a detailed evaluation of our system in terms of confocal Raman microscopy, common multispectral imaging and remote sensing. 相似文献