Digital control of magnetic bearings supporting a multimass flexible rotor

The characteristics of magnetic bearings used to support a three mass flexible rotor operated at speeds up to 14,000 RPM are discussed. The magnetic components of the bearing are of a type reported in the literature previously, but the earlier analog controls were replaced by digital ones. Analog-to-digital and digital-to-analog converters and digital control software were installed in an AT&T PC. This PC-based digital controller was used to operate one of the magnetic bearings on the test rig. Basic proportional-derivative control was applied to the bearings, and the bearing stiffness and damping characteristics were evaluated. Particular attention is paid to the frequency dependent behavior of the stiffness and damping properties, and comparisons are made between the actual controllers and ideal proportional-derivative control

Acute: high-level programming language design for distributed computation

Existing languages provide good support for typeful programming of standalone programs. In a distributed system, however, there may be interaction between multiple instances of many distinct programs, sharing some (but not necessarily all) of their module structure, and with some instances rebuilt with new versions of certain modules as time goes on. In this paper we discuss programming language support for such systems, focussing on their typing and naming issues. We describe an experimental language, Acute, which extends an ML core to support distributed development, deployment, and execution, allowing type-safe interaction between separately-built programs. The main features are: (1) type-safe marshalling of arbitrary values; (2) type names that are generated (freshly and by hashing) to ensure that type equality tests suffice to protect the invariants of abstract types, across the entire distributed system; (3) expression-level names generated to ensure that name equality tests suffice for type-safety of associated values, e.g. values carried on named channels; (4) controlled dynamic rebinding of marshalled values to local resources; and (5) thunkification of threads and mutexes to support computation mobility. These features are a large part of what is needed for typeful distributed programming. They are a relatively lightweight extension of ML, should be efficiently implementable, and are expressive enough to enable a wide variety of distributed infrastructure layers to be written as simple library code above the byte-string network and persistent store APIs. This disentangles the language runtime from communication intricacies. This paper highlights the main design choices in Acute. It is supported by a full language definition (of typing, compilation, and operational semantics), by a prototype implementation, and by example distribution libraries

Genomic Education – Bench to Bedside: A Novel Approach to Teaching Genetic Diagnosis

Problem: Teaching genetic diagnosis is required in all medical schools and physician assistant programs. However, with thousands of relevant findings and thousands more rare diseases, lectures and narrative resources are inadequate for the task. Whatever information that is taught is easily forgotten and does not carry over into the clinic. Many rare disease patients suffer through “diagnostic odysseys” (3 to 30 years to correct diagnosis). Approach: We used a commercially available diagnostic decision support system (DDSS) that encompasses all Mendelian disorders with known genes, together with other conditions in their differential diagnosis, and a case-based educational approach to teach diagnostic skills in a way that could then be replicated in the clinic. After a lecture, which included a demonstration using the DDSS with a sample case, 74 students were assigned to replicate the sample case at home and then complete 7 other anonymized cases, all with known rare diagnoses. After each case, students saved the “patient summary” that included the findings entered and differential diagnosis list and submitted it as homework. Students also completed a questionnaire about their experience, including satisfaction. Outcomes: Students were effective at diagnosing rare diseases in 483 of the 514 testing instances, a 94% success rate, with success defined as the correct diagnosis being listed in the differential diagnosis. Eighty-five percent of students rated this interactive learning session “highly,” encouraged us to repeat the assignment next year, and 89% reported that they wanted to use the DDSS during their clinical rotations in the coming year. Next Steps: We plan to refine the cases, add more material on findings, and ensure that all the synonyms students might use are in the software tool. We plan to repeat the program next year and recommend its use more widely in medical education

Updates in the chronic kidney disease-mineral bone disorder show the role of osteocytic proteins, a potential mechanism of the bone-vascular paradox, a therapeutic target, and a biomarker

The chronic kidney disease-mineral bone disorder (CKD-MBD) is a complex multi-component syndrome occurring during kidney disease and its progression. Here, we update progress in the components of the syndrome, and synthesize recent investigations, which suggest a potential mechanism of the bone-vascular paradox. The discovery that calcified arteries in chronic kidney disease inhibit bone remodeling lead to the identification of factors produced by the vasculature that inhibit the skeleton, thus providing a potential explanation for the bone-vascular paradox. Among the factors produced by calcifying arteries, sclerostin secretion is especially enlightening. Sclerostin is a potent inhibitor of bone remodeling and an osteocyte specific protein. Its production by the vasculature in chronic kidney disease identifies the key role of vascular cell osteoblastic/osteocytic transdifferentiation in vascular calcification and renal osteodystrophy. Subsequent studies showing that inhibition of sclerostin activity by a monoclonal antibody improved bone remodeling as expected, but stimulated vascular calcification, demonstrate that vascular sclerostin functions to brake the Wnt stimulation of the calcification milieu. Thus, the target of therapy in the chronic kidney disease-mineral bone disorder is not inhibition of sclerostin function, which would intensify vascular calcification. Rather, decreasing sclerostin production by decreasing the vascular osteoblastic/osteocytic transdifferentiation is the goal. This might decrease vascular calcification, decrease vascular stiffness, decrease cardiac hypertrophy, decrease sclerostin production, reduce serum sclerostin and improve skeletal remodeling. Thus, the therapeutic target of the chronic kidney disease-mineral bone disorder may be vascular osteoblastic transdifferentiation, and sclerostin levels may be a useful biomarker for the diagnosis of the chronic kidney disease-mineral bone disorder and the progress of its therapy

'Choosing shoes': a preliminary study into the challenges facing clinicians in assessing footwear for rheumatoid patients

Background: Footwear has been accepted as a therapeutic intervention for the foot affected by rheumatoid arthritis (RA). Evidence relating to the objective assessment of footwear in patients with RA is limited. The aims of this study were to identify current footwear styles, footwear characteristics, and factors that influence footwear choice experienced by patients with RA. Methods: Eighty patients with RA were recruited from rheumatology clinics during the summer months. Clinical characteristics, global function, and foot impairment and disability measures were recorded. Current footwear, footwear characteristics and the factors associated with choice of footwear were identified. Suitability of footwear was recorded using pre-determined criteria for assessing footwear type, based on a previous study of foot pain. Results: The patients had longstanding RA with moderate-to severe disability and impairment. The foot and ankle assessment demonstrated a low-arch profile with both forefoot and rearfoot structural deformities. Over 50% of shoes worn by patients were opentype footwear. More than 70% of patients’ footwear was defined as being poor. Poor footwear characteristics such as heel rigidity and sole hardness were observed. Patients reported comfort (17%) and fit (14%) as important factors in choosing their own footwear. Only five percent (5%) of patients wore therapeutic footwear. Conclusions: The majority of patients with RA wear footwear that has been previously described as poor. Future work needs to aim to define and justify the specific features of footwear that may be of benefit to foot health for people with RA

The Association between Seasonal Variation in Vitamin D, Postural Sway, and Falls Risk: An Obversational Cohort Study

Introduction: Low serum vitamin D levels are associated with increased postural sway. Vitamin D varies seasonally. This study investigates whether postural sway varies seasonally and is associated with serum vitamin D and falls. Methods: In a longitudinal observational study, eighty-eight independently mobile community-dwelling older adults (69.7 ± 7.6 years) were evaluated on five occasions over one year, measuring postural sway (force platform), vitamin D levels, fall incidence, and causes and adverse outcomes. Mixed-methods Poisson regression was used to determine associations between measures. Results: Postural sway did not vary over the year. Vitamin D levels varied seasonally (P < 0.001), peaking in summer. Incidence of falls (P=0.01) and injurious falls (P=0.02) were lower in spring, with the highest fall rate at the end of autumn. Postural sway was not related to vitamin D (P=0.87) or fall rates, but it was associated with fall injuries (IRR 1.59 (CI 1.14 to 2.24, P=0.007). Conclusions: Postural sway remained stable across the year while vitamin D varied seasonally. Participants with high values for postural sway demonstrated higher rates of injurious falls. This study provides important evidence for clinicians and researchers providing interventions measuring balance outcomes across seasons

Antimicrobial resistance in equine faecal Escherichia coli isolates from North West England

<p>Abstract</p> <p>Background</p> <p><it>Escherichia coli </it>isolates of equine faecal origin were investigated for antibiotic resistance, resistance genes and their ability to perform horizontal transfer.</p> <p>Methods</p> <p>In total, 264 faecal samples were collected from 138 horses in hospital and community livery premises in northwest England, yielding 296 resistant <it>E. coli </it>isolates. Isolates were tested for susceptibility to antimicrobial drugs by disc diffusion and agar dilution methods in order to determine minimum inhibitory concentrations (MIC). PCR amplification was used to detect genes conferring resistance to: ampicillin (TEM and SHV beta-lactamase), chloramphenicol (<it>catI, catII, catIII </it>and <it>cml</it>), tetracycline <it>(tetA, tetB, tetC, tetD, tet E </it>and <it>tetG</it>), and trimethoprim (<it>dfrA1, dfrA9, dfrA12, dfrA13, dfr7</it>, and <it>dfr17</it>).</p> <p>Results</p> <p>The proportion of antibiotic resistant isolates, and multidrug resistant isolates (MDR) was significantly higher in hospital samples compared to livery samples (MDR: 48% of hospital isolates; 12% of livery isolates, p < 0.001). Resistance to ciprofloxacin and florfenicol were identified mostly within the MDR phenotypes. Resistance genes included <it>dfr</it>, TEM beta-lactamase, <it>tet </it>and <it>cat</it>, conferring resistance to trimethoprim, ampicillin, tetracycline and chloramphenicol, respectively. Within each antimicrobial resistance group, these genes occurred at frequencies of 93% (260/279), 91%, 86.8% and 73.5%, respectively; with 115/296 (38.8%) found to be MDR isolates. Conjugation experiments were performed on selected isolates and MDR phenotypes were readily transferred.</p> <p>Conclusions</p> <p>Our findings demonstrate that <it>E. coli </it>of equine faecal origin are commonly resistant to antibiotics used in human and veterinary medicine. Furthermore, our results suggest that most antibiotic resistance observed in equine <it>E. coli </it>is encoded by well-known and well-characterized resistant genes common to <it>E. coli </it>from man and domestic animals. These data support the ongoing concern about antimicrobial resistance, MDR, antimicrobial use in veterinary medicine and the zoonotic risk that horses could potentially pose to public health.</p

An evaluation of seasonal variations in footwear worn by adults with inflammatory arthritis: a cross-sectional observational study using a web-based survey

Background: Foot problems are common in adults with inflammatory arthritis and therapeutic footwear can be effective in managing arthritic foot problems. Accessing appropriate footwear has been identified as a major barrier, resulting in poor adherence to treatment plans involving footwear. Indeed, previous New Zealand based studies found that many people with rheumatoid arthritis and gout wore inappropriate footwear. However, these studies were conducted in a single teaching hospital during the New Zealand summer therefore the findings may not be representative of footwear styles worn elsewhere in New Zealand, or reflect the potential influence of seasonal climate changes. The aim of the study was to evaluate seasonal variations in footwear habits of people with inflammatory arthritic conditions in New Zealand. Methods: A cross-sectional study design using a web-based survey. The survey questions were designed to elicit demographic and clinical information, features of importance when choosing footwear and seasonal footwear habits, including questions related to the provision of therapeutic footwear/orthoses and footwear experiences. Results: One-hundred and ninety-seven participants responded who were predominantly women of European descent, aged between 46–65 years old, from the North Island of New Zealand. The majority of participants identified with having either rheumatoid arthritis (35%) and/or osteoarthritis (57%) and 68% reported established disease (>5 years duration). 18% of participants had been issued with therapeutic footwear. Walking and athletic shoes were the most frequently reported footwear type worn regardless of the time of year. In the summer, 42% reported wearing sandals most often. Comfort, fit and support were reported most frequently as the footwear features of greatest importance. Many participants reported difficulties with footwear (63%), getting hot feet in the summer (63%) and the need for a sandal which could accommodate a supportive insole (73%). Conclusions: Athletic and walking shoes were the most popular style of footwear reported regardless of seasonal variation. During the summer season people with inflammatory arthritis may wear sandals more frequently in order to accommodate disease-related foot deformity. Healthcare professionals and researchers should consider seasonal variation when recommending appropriate footwear, or conducting footwear studies in people with inflammatory arthritis, to reduce non-adherence to prescribed footwear