SKITTER foot design

A mechanical design team was formed to design a foot for the lunar utility vehicle SKITTER. The primary design was constrained to be a ski pole design compatible with the existing femur-tibia design legs. The lunar environment had several important effects on the foot design. Three materials were investigated for the SKITTER foot: aluminum alloys, cold worked stainless steel alloys, and titanium alloys. Thin film coatings were investigated as a method of wear reduction for the foot. The performance of the foot is dependent on the action of the legs. The range of motion for the legs was determined to be vertical to 15 degrees above horizontal. An impact analysis was performed for the foot movement, but the results were determined to be inconclusive due to unknown soil parameters. The initial foot design configuration consisted of an annulus attached to the pointed pole. The annulus was designed to prevent excess sinkage. Later designs call for a conical shaped foot with a disk at the point of the tibia attachment. The conical design was analyzed for strength and deflection by two different approaches. A deformable body analysis was performed for the foot under crane load in crane position, and also under actuator load in the vertical position. In both cases, the deflection of the foot was insignificant and the stresses well below the strength of the titanium alloy

Economic optimization and parametric analysis of large hybrid ground source heat pump systems: A case study

Hybrid ground source heat pump systems offer a solution to reduce initial costs and make systems more economically viable. Their design is however complex and their financial profitability difficult to establish. The design of hybrid system is usually determined by following rough rules and is neither mathematically rigorous nor optimized. In this paper, a methodology recently introduced by the same authors for economic optimization of hybrid ground source heat pump systems is used to carry out a parametric analysis and assess the impact of uncertainty on the optimal design solution. The results show that all the parameters have significant impact on the optimization, and the ground heat exchanger construction costs and ground source heat pump COP had the most impact on the net present value. However trends are difficult to observe because if the non-linear nature of the problem, and thus there is a need for more robust optimization of hybrid GSHP systems under uncertainty

Orthoplastics in Periprosthetic Joint Infection of the Knee: Treatment Concept for Composite Soft-tissue Defect with Extensor Apparatus Deficiency.

Introduction: Reconstruction of composite soft-tissue defects with extensor apparatus deficiency in patients with periprosthetic joint infection (PJI) of the knee is challenging. We present a single-centre multidisciplinary orthoplastic treatment concept based on a retrospective outcome analysis over 20 years. Methods and Results: One-hundred sixty patients had PJI after total knee arthroplasty. Plastic surgical reconstruction of a concomitant perigenicular soft-tissue defect was indicated in 47 patients. Of these, six presented with extensor apparatus deficiency. One patient underwent primary arthrodesis and five patients underwent reconstruction of the extensor apparatus. The principle to reconstruct missing tissue 'like with like' was thereby favoured: Two patients with a wide soft-tissue defect received a free anterolateral thigh flap with fascia lata; one patient with a smaller soft-tissue defect received a free sensate, extended lateral arm flap with triceps tendon; and two patients who did not qualify for free flap surgery received a pedicled medial sural artery perforator gastrocnemius flap. Despite good functional results 1 year later, long-term follow-up revealed that two patients had to undergo arthrodesis because of recurrent infection and one patient was lost to follow-up. Conclusion: These results show that PJI of the knee and extensor apparatus deficiency is a dreaded combination with a poor long-term outcome. Standardization of surgical techniques for a defined PJI problem and consensus on study variables may facilitate interinstitutional comparisons of outcome data, and hence, improvement of treatment concepts

A specific amino acid motif of HLA-DRB1 mediates risk and interacts with smoking history in Parkinson's disease.

Parkinson's disease (PD) is a neurodegenerative disease in which genetic risk has been mapped to HLA, but precise allelic associations have been difficult to infer due to limitations in genotyping methodology. Mapping PD risk at highest possible resolution, we performed sequencing of 11 HLA genes in 1,597 PD cases and 1,606 controls. We found that susceptibility to PD can be explained by a specific combination of amino acids at positions 70-74 on the HLA-DRB1 molecule. Previously identified as the primary risk factor in rheumatoid arthritis and referred to as the "shared epitope" (SE), the residues Q/R-K/R-R-A-A at positions 70-74 in combination with valine at position 11 (11-V) is highly protective in PD, while risk is attributable to the identical epitope in the absence of 11-V. Notably, these effects are modified by history of cigarette smoking, with a strong protective effect mediated by a positive history of smoking in combination with the SE and 11-V (P = 10-4; odds ratio, 0.51; 95% confidence interval, 0.36-0.72) and risk attributable to never smoking in combination with the SE without 11-V (P = 0.01; odds ratio, 1.51; 95% confidence interval, 1.08-2.12). The association of specific combinations of amino acids that participate in critical peptide-binding pockets of the HLA class II molecule implicates antigen presentation in PD pathogenesis and provides further support for genetic control of neuroinflammation in disease. The interaction of HLA-DRB1 with smoking history in disease predisposition, along with predicted patterns of peptide binding to HLA, provide a molecular model that explains the unique epidemiology of smoking in PD

The BACH classification of long bone osteomyelitis.

OBJECTIVES: The aim of this study was to assess the clinical application of, and optimize the variables used in, the BACH classification of long-bone osteomyelitis. METHODS: A total of 30 clinicians from a variety of specialities classified 20 anonymized cases of long-bone osteomyelitis using BACH. Cases were derived from patients who presented to specialist centres in the United Kingdom between October 2016 and April 2017. Accuracy and Fleiss' kappa (Fκ) were calculated for each variable. Bone involvement (B-variable) was assessed further by nine clinicians who classified ten additional cases of long bone osteomyelitis using a 3D clinical imaging package. Thresholds for defining multidrug-resistant (MDR) isolates were optimized using results from a further analysis of 253 long bone osteomyelitis cases. RESULTS: The B-variable had a classification accuracy of 77.0%, which improved to 95.7% when using a 3D clinical imaging package (p < 0.01). The A-variable demonstrated difficulty in the accuracy of classification for increasingly resistant isolates (A1 (non-resistant), 94.4%; A2 (MDR), 46.7%; A3 (extensively or pan-drug-resistant), 10.0%). Further analysis demonstrated that isolates with four or more resistant test results or less than 80% sensitive susceptibility test results had a 98.1% (95% confidence interval (CI) 96.6 to 99.6) and 98.8% (95% CI 98.1 to 100.0) correlation with MDR status, respectively. The coverage of the soft tissues (C-variable) and the host status (H-variable) both had a substantial agreement between users and a classification accuracy of 92.5% and 91.2%, respectively. CONCLUSIONS: The BACH classification system can be applied accurately by users with a variety of clinical backgrounds. Accuracy of B-classification was improved using 3D imaging. The use of the A-variable has been optimized based on susceptibility testing results.Cite this article: A. J. Hotchen, M. Dudareva, J. Y. Ferguson, P. Sendi, M. A. McNally. The BACH classification of long bone osteomyelitis. Bone Joint Res 2019;8:459-468. DOI: 10.1302/2046-3758.810.BJR-2019-0050.R1

Vaccination with HPV-18 E7-pulsed dendritic cells in a patient with metastatic cervical cancer [7]

To the Editor: The anagement of disseminated carcinoma of the cervix that is no longer amenable to control with surgery or radiation therapy has not improved significantly with the advent of modern chemotherapy. The one-year survival rate remains between 10 percent and 15 percent. Studies have provided a rationale for using dendritic cells as natural adjuvants for human immunotherapy

Engraftment of neural stem cells in the treatment of spinal cord injury

AbstractSpinal cord injury is one of the main causes of disability in the young population. Based on the underlying pathological changes, many modalities of treatments have been trialed. However, the most promising so far, has been the replacement of lost cellular elements, using stem cells and non-stem cells transplantation. The route of cellular administration and engraftment into the site of injury is an important determining factor for functional outcome, and should be chosen to be safe and efficacious in human patients. Herein, we will review the underlying changes following spinal cord injury, and the possible routes of cellular transplantation

What Do We Think We Think We Are Doing?: Metacognition and Self-Regulation in Programming

Metacognition and self-regulation are popular areas of interest in programming education, and they have been extensively researched outside of computing. While computing education researchers should draw upon this prior work, programming education is unique enough that we should explore the extent to which prior work applies to our context. The goal of this systematic review is to support research on metacognition and self-regulation in programming education by synthesizing relevant theories, measurements, and prior work on these topics. By reviewing papers that mention metacognition or self-regulation in the context of programming, we aim to provide a benchmark of our current progress towards understanding these topics and recommendations for future research. In our results, we discuss eight common theories that are widely used outside of computing education research, half of which are commonly used in computing education research. We also highlight 11 theories on related constructs (e.g., self-efficacy) that have been used successfully to understand programming education. Towards measuring metacognition and self-regulation in learners, we discuss seven instruments and protocols that have been used and highlight their strengths and weaknesses. To benchmark the current state of research, we examined papers that primarily studied metacognition and self-regulation in programming education and synthesize the reported interventions used and results from that research. While the primary intended contribution of this paper is to support research, readers will also learn about developing and supporting metacognition and self-regulation of students in programming courses