A set of simple, accurate equations for circular cylindrical elastic shells

Partial differential equations for linear behavior of elastically isotropic circular cylindrical shell under edge and surface loading - structural dynamic

Recent advances in shell theory

The results reviewed are divided into two categories: those that relate two-dimensional shell theory to three-dimensional elasticity theory and those concerned with shell theory per se. In the second category results for general elastic systems that carry over, by specialization or analogy, to shells and results that are unique to shell theory itself are considered

High Prevalence of Hypermobility and Benign Joint Hypermobility Syndrome (BJHS) in Oman

PURPOSE: To ascertain the prevalence of hypermobility and BJHS in a female patient population with musculoskeletal pain and compare the associated features with a pain free control group. RELEVANCE: Hypermobility is linked with increased musculoskeletal signs and symptoms. The existence of hypermobility with pain may indicate the presence of BJHS, which is a heritable connective tissue disorder synonymous with Ehlers-Danlos type III. Hypermobility is known to be race dependant with Asians and Africans being more hypermobile than Caucasians. The fragility of tissues in those with BJHS makes them more vulnerable to pain associated with soft tissue overuse injuries, traumatic synovitis, sprains and recurrent shoulder dislocations (Grahame 2000; Grahame et al 1981; Finterbush and Pogund 1982) it is also associated with delayed tissue healing, impaired proprioception (Mallik et al 1994; Hall et al 1995) and chronic pain. (Harding and Grahame 1990) PARTICIPANTS: 94 Female Omani patients with musculoskeletal pain attending the rehabilitation department outpatient clinics of the Khoula Hospital aged 18–50 were examined. 90 controls of the same age were recruited from the female Omani hospital staff. METHODS: All patients and controls were examined and questioned by one physiotherapist (CC), who had received training from a rheumatologist (RG) in clinical examination of patients at the hypermobility clinic, University College Hospital, London. Patients and controls were examined using the Beighton score and Brighton Criteria. ANALYSIS: Analysis was by χ2 for number of individuals and t-test for joint mobility scores. (Excel® 2002) RESULTS: 51% of patients were found to be hypermobile as opposed to 30% of controls (p = 0.015). 55.3% of patients had features of BJHS as opposed to 21.1% of controls. (p ≤ 0.0001). Significantly more patients presenting with knee pain had BJHS (p = 0.02). There was a non-significant trend for patients with BJHS to re-attend the out patient clinics (p= 0.06). CONCLUSIONS: This study established that this patient population was significantly more hypermobile than a control population. The incidence of BJHS in patients in this study was higher than that noted amongst female Caucasians, but similar to non Caucasians attending rheumatological clinics in the UK. (Grahame and Hakim 2004). Further epidemiological studies are required in other populations to look at patient re-attendance in musculoskeletal clinics and more specifically for those presenting with back and knee pain. IMPLICATIONS: Better recognition and awareness of hypermobility and BJHS will enable patients to receive treatment programmes, modified to take into account tissue fragility, hypermobile joints, impaired proprioception and chronic pain. KEYWORDS: Hypermobility, Pain, Joints. FUNDING ACKNOWLEDGEMENTS: No funding. Jane Simmonds, UCL supervising team, Professor R. Grahame and Dr. A. Hakim from the Hypermobility clinic UCH, London, Professor H. Holmberg, Khoula Hospital Director, Samia Al Marjeby head of rehabilitation, the staff and patients of Khoula Hospital, Muscat, Oman. CONTACT: [email protected] ETHICS COMMITTEE: Khoula Hospital Ethics committee, Khoula Hospital, Muscat, Oman (12/11/2003

The influence of CpG and UpA dinucleotide frequencies on RNA virus replication and characterization of the innate cellular pathways underlying virus attenuation and enhanced replication

Most RNA viruses infecting mammals and other vertebrates show profound suppression of CpG and UpA dinucleotide frequencies. To investigate this functionally, mutants of the picornavirus, echovirus 7 (E7), were constructed with altered CpG and UpA compositions in two 1.1–1.3 Kbase regions. Those with increased frequencies of CpG and UpA showed impaired replication kinetics and higher RNA/infectivity ratios compared with wild-type virus. Remarkably, mutants with CpGs and UpAs removed showed enhanced replication, larger plaques and rapidly outcompeted wild-type virus on co-infections. Luciferase-expressing E7 sub-genomic replicons with CpGs and UpAs removed from the reporter gene showed 100-fold greater luminescence. E7 and mutants were equivalently sensitive to exogenously added interferon-β, showed no evidence for differential recognition by ADAR1 or pattern recognition receptors RIG-I, MDA5 or PKR. However, kinase inhibitors roscovitine and C16 partially or entirely reversed the attenuated phenotype of high CpG and UpA mutants, potentially through inhibition of currently uncharacterized pattern recognition receptors that respond to RNA composition. Generating viruses with enhanced replication kinetics has applications in vaccine production and reporter gene construction. More fundamentally, the findings introduce a new evolutionary paradigm where dinucleotide composition of viral genomes is subjected to selection pressures independently of coding capacity and profoundly influences host–pathogen interactions

Self-contained breathing apparatus

A self-contained breathing apparatus with automatic redundant fluid pressure controls and a facemask mounted low pressure whistle alarm is described. The first stage of the system includes pair of pressure regulators connected in parallel with different outlet pressures, both of which reduce the pressure of the stored supply gas to pressures compatible with the second stage breathing demand regulator. A primary regulator in the first stage delivers a low output pressure to the demand regulator. In the event of a failure closed condition of the primary regulator an automatic transfer valve switches on the backup regulator. A warning that the supply pressure has been depleted is also provided by a supply pressure actuated transfer valve which transfers the output of the first stage pressure regulators from the primary to the backup regulator. The alarm is activated in either the failure closed condition or if the supply pressure is reduced to a dangerously low level

Quantum nondemolition measurement of a nonclassical state of a massive object

While quantum mechanics exquisitely describes the behavior of microscopic systems, one ongoing challenge is to explore its applicability to systems of larger size and mass. Unfortunately, quantum states of increasingly macroscopic objects are more easily corrupted by unintentional measurements from the classical environment. Additionally, even the intentional measurements from the observer can further perturb the system. In optomechanics, coherent light fields serve as the intermediary between the fragile mechanical states and our inherently classical world by exerting radiation pressure forces and extracting mechanical information. Here we engineer a microwave cavity optomechanical system to stabilize a nonclassical steady-state of motion while independently, continuously, and nondestructively monitoring it. By coupling the motion of an aluminum membrane to two microwave cavities, we separately prepare and measure a squeezed state of motion. We demonstrate a quantum nondemolition (QND) measurement of sub-vacuum mechanical quadrature fluctuations. The techniques developed here have direct applications in the areas of quantum-enhanced sensing and quantum information processing, and could be further extended to more complex quantum states.Comment: 9 pages, 6 figure