Partial body weight support treadmill training speed influences paretic and non-paretic leg muscle activation,stride characteristics,and ratings of perceived exertion during acute stroke rehabilitation

BackgroundIntensive task-specific training is promoted as one approach for facilitating neural plastic brain changes and associated motor behavior gains following neurologic injury. Partial body weight support treadmill training (PBWSTT), is one task-specific approach frequently used to improve walking during the acute period of stroke recovery (<1 month post infarct). However, only limited data have been published regarding the relationship between training parameters and physiologic demands during this early recovery phase.ObjectiveTo examine the impact of four walking speeds on stride characteristics, lower extremity muscle demands (both paretic and non-paretic), Borg ratings of perceived exertion (RPE), and blood pressure.DesignA prospective, repeated measures design was used.MethodsTen inpatients post unilateral stroke participated. Following three familiarization sessions, participants engaged in PBWSTT at four predetermined speeds (0.5, 1.0, 1.5 and 2.0 mph) while bilateral electromyographic and stride characteristic data were recorded. RPE was evaluated immediately following each trial.ResultsStride length, cadence, and paretic single limb support increased with faster walking speeds (p ⩽ 0.001), while non-paretic single limb support remained nearly constant. Faster walking resulted in greater peak and mean muscle activation in the paretic medial hamstrings, vastus lateralis and medial gastrocnemius, and non-paretic medial gastrocnemius (p ⩽ 0.001). RPE also was greatest at the fastest compared to two slowest speeds (p < 0.05).ConclusionsDuring the acute phase of stroke recovery, PBWSTT at the fastest speed (2.0 mph) promoted practice of a more optimal gait pattern with greater intensity of effort as evidenced by the longer stride length, increased between-limb symmetry, greater muscle activation, and higher RPE compared to training at the slowest speeds.     

Hydrogen-assisted damage in austenite/martensite dual-phase steel

For understanding the underlying hydrogen embrittlement mechanism in transformation-induced plasticity steels, the process of damage evolution in a model austenite/martensite dual-phase microstructure following hydrogenation was investigated through multi-scale electron channelling contrast imaging and in situ optical microscopy. Localized diffusible hydrogen in martensite causes cracking through two mechanisms: (1) interaction between {1?1?0}_M localized slip and {1?1?2}_M twin and (2) cracking of martensite–martensite grain interfaces. The former resulted in nanovoids along the {1?1?2}_M twin. The coalescence of the nanovoids generated plate-like microvoids. The latter caused shear localization on the specific plane where the crack along the martensite/martensite boundary exists, which led to additional martensite/martensite boundary cracking.     

Cascade effects on the irradiation stability of amorphous SiOC

We studied the heavy ion radiation tolerance of amorphous silicon oxycarbide (SiOC) alloys by in situ Kr ion irradiation within a transmission electron microscopy. The amorphous SiOC thin films were grown via co-sputtering from SiO₂ and SiC targets on a surface-oxidized Si (100) substrate. These films were irradiated by 1 MeV Kr ions at both room temperature and 300 °C with damage levels up to 5 displacements per atom (dpa). TEM characterization shows no sign of crystallization, void formation or segregation in all irradiated samples. Our findings suggest that SiOC alloys are a class of promising radiation tolerant materials.     

Emotional disturbances and their interaction with neuropsychological deficits

The interaction and relationships between neuropsychological tests (which are principally oriented to intellectual and cognitive abilities) and tests of personality and emotional status are complex, but nevertheless important in the clinical assessment of brain-damaged persons. Are indications of emotional disturbances to be expected as a direct consequence of brain damage? If so, how can the indications of emotional disturbances be differentiated from results obtained with psychiatrically disturbed (non-brain-damaged) subjects? Some authors have presumed that emotional disturbances, such as depression, acute anxiety, etc., in their own right cause impaired performances on neuropsychological tests, whereas other authors have proposed that brain damage predisposes the individual to demonstrate evidence of emotional disturbances. If emotional disturbances cause impairment on neuropsychological tests, why is it that so many emotionally disturbed persons without brain damage tend to perform normally on neuropsychological tests? This review of relevant publications considers (1) different general approaches to these questions and their implications for neuropsychology, (2) evidence of differential sensitivity to brain damage of neuropsychological and emotional instruments, (3) the sensitivity and specificity of self-assessments and complaints of head-injured subjects, (4) MMPI findings among head-injured subjects and in interaction with neuropsychological measurements, and (5) principles and guidelines that may be of value in clinical application of findings reported in the literature.     

Psychological adjustment of pediatric lung transplantation candidates and their parents

Investigated psychological functioning of 45 children and adolescents (ages 5 to 17 years) and their parents presenting at a major medical center for evaluation for lung transplantation. Patients completed self-reports, and parents completed measures on their children's behavior problems and emotional distress as well as on their own symptoms of distress. In general, children and their parents reported normal functioning on standard psychological measures. Few children fell in the clinically significant range, whereas 21% of mothers and 14% of fathers reported clinically significant levels of distress. Older children reported lower levels of depressive symptoms than younger children, and patients with cystic fibrosis manifested lower levels of internalizing symptoms than those with other pulmonary diseases. Findings demonstrate the resiliency of children and their parents facing a stressful point in the child's medical status and document the usefulness of psychological screening of patients and parents to identify those in need of clinical intervention.     

Publication trends in 25 years of the Journal of Applied Behavior Analysis

All articles published in the first 25 years of JABA (1968 to 1992) were reviewed to classify the percentage of articles published in the following categories: (a) type of article, (b) subjects, (c) setting, (d) behavior-change agent, (e) target behavior, (f) use of basic principles, and (g) miscellaneous procedures. Overall percentages and trends are reported in each category. Results indicate an increase in the percentage of articles with participants and target behaviors in developmental disabilities and a decrease in the percentage of studies targeting academic behavior, verbal behavior, and other child behavioral excesses. The most frequent setting continues to be a school; however, there is a clear trend towards community and other naturalistic settings. Results also highlight the increasing complexity and multicomponent nature of JABA interventions. Potential implications for future applications are discussed.     

Orthogonal rotations to maximal agreement for two or more matrices of different column orders

Methods for orthogonal Procrustes rotation and orthogonal rotation to a maximal sum of inner products are examined for the case when the matrices involved have different numbers of columns. An inner product solution offered by Cliff is generalized to the case of more than two matrices. A nonrandom start for a Procrustes solution suggested by Green and Gower is shown to give better results than a random start. The Green-Gower Procrustes solution (with nonrandom start) is generalized to the case of more than two matrices. Simulation studies indicate that both the generalized inner product solution and the generalized Procrustes solution tend to attain their global optima within acceptable computation times. A simple procedure is offered for approximating simple structure for the rotated matrices without affecting either the Procrustes or the inner product criterion.The authors are obliged to Charles Lewis for helpful comments on a previous draft of this paper and to Frank Brokken for preparing a computer program that was used in this study.     

目标显著性和任务重要性对数学学业不良生和学优生前瞻记忆和前瞻干扰效应的影响

有问卷调查表明,个体的学业成绩特别是数学成绩与前瞻记忆表现有一定的相关,学业不良生报告更多的前瞻记忆失败。也有实验研究显示,学业不良生在很多情况下前瞻记忆表现劣于学优生。但是,影响学业不良生前瞻记忆表现的因素却并不是很明确。本研究从目标显著性和任务重要性这两个可以着手于改善前瞻记忆的主要因素入手,考察其对数学学业不良生和学优生事件性前瞻记忆和前瞻干扰效应的影响,以期为提高学业不良生的前瞻记忆表现提供实证依据。 采用2学业成就（学业不良生、学优生）×2前瞻记忆任务重要性（强调重要、不强调）×2目标显著性（显著、不显著）混合实验设计,目标显著性为被试内变量,其他两个因素为被试间变量,在双任务实验范式（前瞻记忆任务镶嵌于进行中任务）中,考察三个因素对前瞻记忆正确率和反应时的影响。此外,被试还需完成基线条件,在基线条件下被试只有进行中任务,没有前瞻记忆任务,通过实验条件和基线条件的正确率和反应时差异,考察前瞻记忆任务对进行中任务的干扰效应,推测前瞻记忆的加工机制。结果表明,学业不良生在所有前瞻记忆任务表现均劣于学优生;目标显著性与前瞻记忆任务重要性对前瞻记忆正确率有显著的交互作用,强调任务重要性使目标不显著条件下的前瞻记忆正确率提高,对显著条件的前瞻记忆正确率没有影响。强调任务重要性使所有实验条件的前瞻记忆反应时下降,目标显著使所有实验条件的前瞻记忆正确率提高。所有实验条件进行中任务正确率低于基线条件,反应时也慢于基线条件,表明执行前瞻记忆任务对进行中任务产生了干扰,学业不良生和学优生在本实验条件下对前瞻记忆任务均采用监控的加工方式。结果说明,学业不良生前瞻记忆成绩较差,可以通过设置显著的目标提高其前瞻记忆成绩,当目标显著时无需强调其重要性,若无法设置显著的目标,则通过强调任务重要性提高前瞻记忆表现。     

对我国脑死亡立法问题的反思

在对1999年以来我国脑死亡问题的研究成果进行初步梳理的基础上,针对我国学者主张脑死亡立法的主要论据,提出并分析了脑死亡问题的三个主要问题：（1）脑死亡是真正的死亡吗？（2）能否以经济效率的考量来定义生死？（3）器官移植和脑死亡到底有什么关系？还提出,脑死亡立法需要在我国现实的医疗卫生条件下进行讨论。     

脑死亡立法的若干法律问题探讨

因为关系到基本人权,脑死亡立法应当由全国人民代表大会立法通过。制定科学的脑死亡标准和严谨的脑死亡判定程序是保障其接近正义的必需。在脑死亡判定方面应充分地保障患者生命权、自主选择权,尊重患者以及家属的知情同意权,保障患者的基本权利是脑死亡立法的核心所在。器官移植不是脑死亡立法的理由。