Natural Convection Heat Transfer in a Porous Cavity with Sinusoidal Temperature Distribution Using Cu/Water Nanofluid: Double MRT Lattice Boltzmann Method

In this study, natural convection flow in a porous cavity with sinusoidal temperature distribution has been analyzed by a new double multi relaxation time (MRT) Lattice Boltzmann method (LBM). We consider a copper/water nanofluid filling a porous cavity. For simulating the temperature and flow fields, D2Q5 and D2Q9 lattices are utilized respectively, and the effects of different Darcy numbers (Da) (0.001-0.1) and various Rayleigh numbers (Ra) ($10^3$-$10^5$) for porosity ($ε$) between 0.4 and 0.9 have been considered. Phase deviation ($θ$) changed from 0 to $π$ and the volume fraction of nanoparticles (Ø) varied from 0 to 6%. The present results show a good agreement with the previous works, thus confirming the reliability the new numerical method proposed in this paper. It is indicated that the heat transfer rate increases at increasing Darcy number, porosity, Rayleigh number, the volume fraction of nanoparticles and phase deviation. However, the most sensitive parameter is the Rayleigh number. The maximum Nusselt deviation is 10%, 32% and 33% for Ra=$10^3$, $10^4$ and $10^5$, respectively, with $ε = 0.4$ to $ε = 0.9$. It can be concluded that the effect of Darcy number on the heat transfer rate increases at increasing Rayleigh number, yielding a maximum enhancement of the average Nusselt number around 12% and 61% for Ra=$10^3$ and Ra=$10^5$, respectively.     

医院多通道冗余信息网建设

本文首先介绍了浙江大学医学院附属妇产科医院的概况与网络建设需求,然后提出了大中型医院信息网建设的设计原则。依据这些设计原则,提出了医院多通道冗余信息网建设的技术实现方案。经过长时间的运行,证明多通道冗余信息网是稳定可靠的。     

Effect of brain and spinal cord injuries on motor imagery

Summary The timing of mentally executed movements was measured in ten patients with hemiplegia, tetraplegia and paraplegia. In hemiplegic patients a significant difference in mental duration times was found between the paralysed and the normal represented limb. The paralysed limb was mentally much slower than the healthy one. In contrast, movement times in tetraplegic and paraplegic patients did not differ from those in normal subjects. All patients reported a sensation of subjective effort accompanying the execution of the mental tasks. These observations are compatible with an outflow processing underlying motor imagery.     

55例多梗塞性痴呆患者脑脊液TNF和NSE的测定及其临床意义

目的　研究多梗塞性痴呆 (MID)患者脑脊液 (CSF)中肿瘤坏死因子 (TNF α)和神经元特异性烯醇酶 (NSE)的含量变化及临床意义。方法　采用放射免疫分析法对 55例MID患者CSF中TNF α进行测定 ;采用双抗体夹心ELISA法测定NSE浓度。并与同期住院的 72例脑梗塞 (CI)患者及 3 2例神经系统功能性疾病 (Control)患者进行比较。患者的智能水平测定采用简易智能量表(MMSE) ,并参考Hachinski缺血评分及DSM Ⅳ诊断标准。结果　MID急性发作期及CI急性期CSF中TNF α、NSE的浓度均非常显著高于Control组 (P <0 .0 1 ) ;MID稳定期及CI恢复期CSF中TNF α的浓度显著高于Control组 (P <0 .0 5) ;MID稳定期CSF中TNF α的浓度同CI恢复期组差异不显著 (P >0 .0 5)。而MID稳定期CSF中NSE浓度低于Control组和CI恢复期组 (P <0 .0 5)。各组CSF中TNF α、NSE的浓度与MMSE评分无显著相关性 (P >0 .0 5)。结论　MID急性发作期与稳定期患者CSF中TNF α、NSE含量呈非一致性变化。MID患者CSF中TNF α、NSE含量变化可能客观地反映患者脑细胞缺血缺氧性损害。但TNF α、NSE含量变化不能直接反应MID患者的智能状态。     

儿童先天性心脏病各分型致病因素的多因多果研究

目的 为制定先天性心脏病一级预防措施提供科学的参考依据,方法 对５１０例先天性心脏病（ＣＨＤ）患儿进行１：２病例对照配对调查,其中室间隔缺损、房间隔缺损、法乐氏综合征和动脉导管未闭４种主要分型ＣＨＤ各１０２例,其他分型ＣＨＤ共１０２例,在建立总的不分型ＣＨＤ与各危险因素的条件Ｌｏｇｉｓｔｉｃ模型并筛选出ＣＨＤ总的危险因素之后,采用多个因素量和多个自变量的条件Ｌｏｇｉｓｔｉｃ模型,对各分型ＣＨＤ与可     

Evidence for opiate-activated NMDA processes masking opiate analgesia in rats

The acute interaction between opioid receptors and N-methyl-D-aspartate (NMDA) receptors on nociception was examined in rats using tail-flick and paw-pressure vocalisation tests. When injected at various times (1 to 6 h) after morphine (5 to 20 mg/kg, i.v.) or fentanyl (4x40 microgram/kg, i.v.), the opioid receptor antagonist naloxone (1 mg/kg, s.c.) not only abolished the opiate-induced increase in nociceptive threshold, but also reduced it below the basal value (hyperalgesia). The noncompetitive NMDA receptor antagonist MK-801 (0.15 or 0.30 mg/kg, s.c.) prevented the naloxone-precipitated hyperalgesia and enhanced the antinociceptive effects of morphine (7.5 mg/kg, i.v.) and fentanyl (4x40 microgram/kg, i.v.). These results indicate that the antinociceptive effects of morphine and fentanyl, two opiate analgesics widely used in humans in the management of pain, are blunted by concomitant NMDA-dependent opposing effects which are only revealed when the predominant antinociceptive effect is sharply blocked by naloxone. This study provides new rationale for beneficial adjunction of NMDA receptor antagonists with opiates for relieving pain by preventing pain facilitatory processes triggered by opiate treatment per se.     

Evaluating problem-based learning in a multilingual student population

OBJECTIVES: The University of Natal Medical School in South Africa provides training for a student body composed of two groups: one with English as a first language and the other with an African language as a first language and English as the second. A new methodology was developed to evaluate an innovative course using modified problem-based learning techniques in this heterogeneous environment. DESIGN: The learning model proposed required achieving a balance of three components: content, enquiry/learning process and social interaction/group process. A multidimensional system, felt to be consistent with this educational philosophy, was developed using seven different quantitative and qualitative techniques. SETTING: The University of Natal Medical School. SUBJECTS: First-year multilingual medical students. RESULTS: The results revealed that social interaction was highly successful in reducing barriers between the student groups and between students and facilitators. However, the emphasis on group participation may have overshadowed the enquiry process, leading to superficial discussions of problems and feelings of repetitiveness. During the course students and facilitators expressed concern that the innovative assessments used did not assess the course content adequately. While the group presentations and projects were useful exercises for consolidation and group interaction, they did not enable facilitators to identify struggling students. CONCLUSIONS: The outcome of the evaluation stressed the need of achieving an appropriate balance both in the curriculum and assessments of the three components of the learning model, particularly in a setting where student backgrounds and language ability differ. Multidimensional methodology is needed for effective evaluation that promotes critical reflection.     

How do normal subjects learn a simple adaptative task: How and why do paranoid schizophrenic patients fail?

Summary The authors studied the behavior of normal subjects and paranoid schizophrenic patients in a simple problem-solving situation. The schizophrenics were divided into two sample groups, one of individuals under treatment and the other of individuals not under treatment.The learning process involved in this problem-solving situation is very similar to an instrumental conditioning, and can be understood by means of the following assumptions: (1) the subjects use decision functions in reacting to the stimuli, although they may be not fully aware of this; (2) learning is the result of successive transformations of these decisions in the course of time; (3) the changes have specific probabilities and are related to (a) those responses which are made to the latest stimuli, and (b) a differential probability for decision functions which were effective, or only interrupted painful reinforcement, or were completely ineffective.In schizophrenics further factors of importance were (1) an inertia factor and (2) the rigidly continued use of unsuccessful or only partially successful decision criteria.The authors used a systems theory based on Galois field theory and a calculus of operators specifying three groups of subjects. A computer program based on these hypotheses was tested in a simulation experiment.The statistical evaluation of the results showed a congruence between the theoretical approach and the experimental data.This work was carried out with financial support from the Institute de Alta Cultura, Lisbon, between 1970 and 1974     

Correlation of freeze-fracture and scanning electron microscopy of epiphyseal chondrocytes

Summary Chondrocytes in epiphyseal cartilage were examined by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) using freeze-fracture techniques. Freeze-fracture replicas showed large numbers of fingerlike, 0.11–0.15 m diameter, projections from the chondrocyte surface, with numerous 95–180 Å diameter intramembranous particles associated with both the cell membrane surface and these projections. With SEM, these cytoplasmic projections were also obvious, but appeared collapsed into clusters of globular-shaped projections on the surface of the chondrocytes. With freeze-fracture techniques, in which shrinkage artifacts were essentially eliminated, the cytoplasmic projections were often seen in intimate contact with the extracapsular matrix. However, with chondrocytes prepared by both SEM and conventional TEM, there was evidence of shrinkage, the cytoplasmic projections having little contact with the extracapsular matrix. These findings show that the cytoplasmic processes are not artifacts of tissue processing and provide morphological evidence in support of the hypothesis that matrix vesicles are of cellular origin.Correlation of Freeze-Fracture and Scanning Electron Microscopy of Epiphyseal Chondrocytes