This paper proposes a human–machine-centered approach to lower limb prosthetic design. The approach is based on a profound analysis and modeling of human factors from user and expert survey data. ...With this knowledge, user demands are considered in the prioritization of technical requirements. To evaluate the design framework, it is applied to the example of the design of a powered prosthetic knee. Key result of this application are a distinct changes in technical requirement priorities that might yield completely different prosthetic designs. Thereby, the potential of the proposed method is substantiated while a practical evaluation is aspect to future studies. Beyond this, the method is easily transferable to other robotic devices operating close to their users, e.g., exoskeletons or teleoperators.
•A method for systematic consideration of human factors in lower limb prosthetic design is proposed.•Seven human factors are determined, analyzed, and modeled with user and expert survey data.•A discussion of experts ranks technical requirements based on their connection to human factors.•Application to a powered prosthetic knee indicates distinct changes in technical design.•The method is easily transferable to other robotic devices operating close to their users.
Literature shows a relationship between pain, personal as well as emotional factors. Subjects high in trait anxiety experience more pain than low anxiety subjects (Graffenried, 1977). Furthermore ...expectations and emotions about aversive events can change the perception of objective identical stimuli. Distinct emotions e.g. fear and anxiety differ in their neuronal and physiological patterns as well as in their behavioral consequences. For this reason they also vary in the direction they modulate pain. Anxiety leads to increased pain whereby fear decreases it (Ploghaus et al. 2003). Thereby one important factor is the subjective estimation of aversive upcoming events. Laux' s research (1981) indicates that people low or high in trait anxiety asses situations differently. People high in trait anxiety are threatened by situations more often. This study examines the impact of trait anxiety on individual pain perception and whether there are differences in pain perception after aversive visual information (AVI) exposition in subjects with high and low anxiety values. 29 subjects divided in two anxiety groups, participated in the study. Measures were the STAI state ratings and pain thresholds before and after experimental manipulation. To determine maximal tolerable pain threshold, subjects receivde electrical stimuli with increasing intensity. After assessment of initial pain thresholds subjects were exposed to AVI. People high in trait anxiety showed a significant increase of pain thresholds after experimental manipulation, Z= −3.185, p<.001. A Wilcoxon-Test for peoples' thresholds low in trait anxiety showed no significant effect. Results are discussed regarding possible interventions for people with chronic pain.
Xenograft models of chronic phase human chronic myeloid leukemia (CML) have been difficult to develop because of the persistence of normal hematopoietic stem cells in most chronic phase CML patients ...and the lack of methods to selectively isolate the rarer CML stem cells. To circumvent this problem, we first identified nine patients' samples in which the long-term culture-initiating cells were predominantly leukemic and then transplanted cells from these samples into sublethally irradiated NOD/SCID and NOD/SCID-beta2microglobulin-/- mice. This resulted in the consistent and durable (>5 months) repopulation of both host genotypes with similar numbers of BCR-ABL+/Ph+ cells. The regenerated leukemic cells included an initial, transient population derived from CD34+CD38+ cells as well as more sustained populations derived from CD34+CD38- progenitors, indicative of a hierarchy of transplantable leukemic cells. Analysis of the phenotypes produced revealed a reduced output of B-lineage cells, enhanced myelopoiesis with excessive production of erythroid and megakaropoietic cells and the generation of primitive (CD34+) leukemic cells displaying an autocrine IL-3 and G-CSF phenotype, all characteristics of primary CML cells. These findings demonstrate the validity of this xenograft model of chronic phase human CML, which should enable future investigation of disease pathogenesis and new approaches to therapy.
The integration of prostheses or wearable robotics into the body schema of their users is a fundamental requirement for the acceptance and control of such artificial devices. Duration and progress of ...integration are primarily influenced by visual, tactile, and proprioceptive perception. This paper describes the Int 2 Bot, a robot for the assessment of lower limb body schema integration during postural motion. The robot is designed to imitate human squatting movements to investigate the integration of artificial limbs into the body schema. The psychological and technical concepts as well as the mechatronic implementation and control are presented along with interface extensions comprising human knee position sensing and tactile user-feedback. The performance of the robot is examined by experiments excluding and including the human-robot interface and a human user. Those without interface show that the robot itself can perform considerably fast squats with 0.8 Hz, which comes up to maximum human capabilities. The computed torque control achieves good tracking results and fuzzy-based friction compensation further reduces position errors by up to 50%. Yet, results considering the vision-based part of the human-robot interface show that the setup is mainly limited due to delays in motion acquisition with the RGB-D sensor.
In this study, we describe the successful use of a gene transfer approach to demonstrate the ability of forced BCR-ABL expression to deregulate the growth and differentiation of primitive naive human ...hematopoietic cells after their transplantation into immunodeficient mice. Human CD34+ cord blood cells were exposed to an MSCV retrovirus containing a BCR-ABL-IRES-GFP (P210) cassette and then injected immediately into sublethally irradiated nonobese diabetic-severe combined immunodeficiency (NOD/SCID) or NOD/SCID-beta2microglobulin-/- mice. P210- and control-transduced (GFP+) human hematopoietic cells were produced in the bone marrow of the mice at similar levels until termination of the experiments 5-6 months later. However, the P210-transduced cells produced a markedly different spectrum of progeny, with an increased ratio of myeloid to B-lymphoid cells and a frequently prolonged increase in erythroid and megakaryocytic cells. After 5 months, several of the mice transplanted with P210-transduced cells developed an increased WBC count and/or splenomegaly due to an expansion of the human GFP+ population. These findings demonstrate that forced expression of BCR-ABL in primitive transplantable human hematopoietic cells is sufficient to cause a rapid and persistent deregulation of their growth and differentiation in vivo with occasional evidence after several months of progression to an early stage of disease.
Clinical success in tumor vaccination frequently does not reach expectation. Since vaccination protocols are quite variable, we used the murine renal cell carcinoma line RENCA transfected with the ...lacZ gene (RENCA-beta-gal) to compare the efficacy of two different vaccination strategies or their combination and to elaborate on the underlying mechanisms. BALB/c mice were vaccinated either with naked lacZ DNA or with attenuated Salmonella typhimurium transformed with lacZ DNA or with dendritic cells (DC) loaded with the beta-galactosidase protein or mice were vaccinated with both DNA and protein. Although all regimens led to a prolongation of survival time, oral vaccination with transfected S. typhimurium followed by i.v. transfer of protein-loaded DC provided the optimal schedule. In this setting, >50% of mice remained tumor free after challenge with 10 times the lethal tumor dose of RENCA-beta-gal. As explored in transfer experiments, the superior efficacy of combining DNA and protein vaccination is due to the facts that 1) optimal protection depends on both activated CD4(+) and CD8(+) cells and 2) CD8(+) CTL are most strongly activated by vaccination with transformed Salmonella, whereas vaccination with protein-loaded DC is superior for the activation of Th. The latter induced sustained activation of CTL and recruitment of nonadaptive defense mechanisms. The data demonstrate the strength of DNA vaccination, particularly by the oral route, and provide evidence that a combined treatment with protein-loaded DC can significantly increase the therapeutic efficacy.
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