A flexible electronic controller for a manipulator-type robot

Manipulator arm construction has changed little over the decades and is unlikely to change radically in the near future. The mechanical design necessary to achieve dexterity results in a system with complex dynamic properties. However, many manipulator manufacturers choose to ignore this complexity, concentrating on the mechanical design aspects rather than the design of the dynamic controller. In most cases, simple fixed-parameter single-loop PID compensators are utilised. In spite of the fact that the compensators are implemented on programmable devices, there is simply not enough processing power available to implement an improved dynamic control strategy. A multiprocessor controller has been developed which allows all the hierarchical levels of a manipulator controller to be implemented. The major advantage of the new controller is its ability to handle complex and time consuming dynamic algorithms for positioning of the robot end effector. This has been accomplished by adopting a master/slave multiprocessor configuration comprising a 20 MHz IBM PC/AT (80386) with a number of DSP cards based around the NEC 77230 floating-point DSP chip. Analog and digital input/output interfaces are provided for reading position signals and providing command signals. Tile motivation for the provision of such a controller was the desire to implement linear and nonlinear self-tuning control strategies. Both centralised (multivariable) and decentralized (single-loop) control strategies are considered and the new controller caters for both schemes by virtue of (a) the master/slave configuration with individual DSP boards for each joint, and (b) inter-board communications, allowing joint interactions to be catered for. In the paper, some of the identification algorithms required to support the nonlinear self-tuning strategies are described and real-time results presented. These results demonstrate the operation of the new controller and indicate some of its capabilities

Energy Cost of Land and Shallow Water Walking in Females who are Overweight and Obese

Nineteen overweight or obese females completed three 10-minute experimental trials including a self-selected pace shallow water walking trial, a matched heart rate response land walking trial, and a self-selected pace land walking trial. Energy expenditure (kcal·min-1) was computed from expired gases assessed via indirect calorimetry. Results showed energy expenditure was lower (p= 0.046) during shallow water walking (6.46 ± 1.38 kcal·min-1) compared to matched heart rate response land walking trial (7.26 ± 1.29 kcal·min-1), with no significant difference in between shallow water and self-selected pace land walking (6.92 ± 1.61 kcal·min-1 ). The present study did not demonstrate superior energy cost of shallow water walking. However, results demonstrate that shallow water walking elicits an increase in energy expenditure, which may indicate that this form of activity is a reasonable alternative to land-based walking. Moreover, this form of activity may be particularly effective for individuals with mobility limitations during land-based exercise

Alveolar Soft Part Sarcoma Metastatic to Small Bowel Mucosa Causing Polyposis and Intussuseption

A report of alveolar soft part sarcoma metastatic to the small bowel is presented. Hematogenous metastases to the small bowel from primary tumors outside the abdominal cavity are uncommon, and most remain asymptomatic and are not discovered until autopsy. However, small bowel metastases can lead to intestinal obstruction, intussuseption or even perforation. While metastases to the small bowel have been described for other tumor types, including melanoma and lung cancer, this is extremely uncommon for sarcoma, especially alveolar soft part sarcoma. We describe a 42-year-old male with a long history of alveolar soft part sarcoma, metastatic to the lung and brain, who developed an intussuseption from metastases to the small bowel

The anti-tumor effect of Apo2L/TRAIL on patient pancreatic adenocarcinomas grown as xenografts in SCID mice

BACKGROUND: Apo2L/TRAIL has considerable promise for cancer therapy based on the fact that this member of the tumor necrosis factor family induces apoptosis in the majority of malignant cells, while normal cells are more resistant. Furthermore, in many cells, when Apo2L/TRAIL is combined with chemotherapy, the effect is synergistic. The majority of this work has been carried out using cell lines. Therefore, investigation of how patient tumors respond to Apo2L/TRAIL can validate and/or complement information obtained from cell lines and prove valuable in the design of future clinical trials. METHODS: We have investigated the Apo2L/TRAIL sensitivity of patient derived pancreatic tumors using a patient tumor xenograft/ SCID mouse model. Mice bearing engrafted tumors were treated with Apo2L/TRAIL, gemcitabine or a combination of both therapies. RESULTS: Patient tumors grown as xenografts exhibited a spectrum of sensitivity to Apo2L/TRAIL. Both Apo2L/TRAIL sensitive and resistant pancreatic tumors were found, as well as tumors that showed heterogeneity of response. Changes in apoptotic signaling molecules in a sensitive tumor were analyzed by Western blot following Apo2L/TRAIL treatment; loss of procaspase 8, Bid and procaspase 3 was observed and correlated with inhibition of tumor growth. However, in a tumor that was highly resistant to killing by Apo2L/TRAIL, although there was a partial loss of procaspase 8 and Bid in response to Apo2L/TRAIL treatment, loss of procaspase 3 was negligible. This resistant tumor also expressed a high level of the anti-apoptotic molecule Bcl-X(L )that, in comparison, was not detected in a sensitive tumor. Importantly, in the majority of these tumors, addition of gemcitabine to Apo2L/TRAIL resulted in a greater anti-tumor effect than either therapy used alone. CONCLUSION: These data suggest that in a clinical setting we will see heterogeneity in the response of patients' tumors to Apo2L/TRAIL, including tumors that are highly sensitive as well as those that are resistant. While much more work is needed to understand the molecular basis for this heterogeneity, it is very encouraging, that Apo2L/TRAIL in combination with gemcitabine increased therapeutic efficacy in almost every case and therefore may be a highly effective strategy for controlling human pancreatic cancer validating and expanding upon what has been reported for cell lines