Inter-lamellar shear resistance confers compressive stiffness in the intervertebral disc: An image-based modelling study on the bovine caudal disc

The intervertebral disc withstands large compressive loads (up to nine times bodyweight in humans) while providing flexibility to the spinal column. At a microstructural level, the outer sheath of the disc (the annulus fibrosus) comprises 12–20 annular layers of alternately crisscrossed collagen fibres embedded in a soft ground matrix. The centre of the disc (the nucleus pulposus) consists of a hydrated gel rich in proteoglycans. The disc is the largest avascular structure in the body and is of much interest biomechanically due to the high societal burden of disc degeneration and back pain. Although the disc has been well characterized at the whole joint scale, it is not clear how the disc tissue microstructure confers its overall mechanical properties. In particular, there have been conflicting reports regarding the level of attachment between adjacent lamellae in the annulus, and the importance of these interfaces to the overall integrity of the disc is unknown. We used a polarized light micrograph of the bovine tail disc in transverse cross-section to develop an image-based finite element model incorporating sliding and separation between layers of the annulus, and subjected the model to axial compressive loading. Validation experiments were also performed on four bovine caudal discs. Interlamellar shear resistance had a strong effect on disc compressive stiffness, with a 40% drop in stiffness when the interface shear resistance was changed from fully bonded to freely sliding. By contrast, interlamellar cohesion had no appreciable effect on overall disc mechanics. We conclude that shear resistance between lamellae confers disc mechanical resistance to compression, and degradation of the interlamellar interface structure may be a precursor to macroscopic disc degeneration.

Pain in juvenile idiopathic arthritis : parents and children as agents of disease management

Juvenile idiopathic arthritis (JIA) is a severe childhood disease usually characterized by long-term morbidity, unpredictable course, pain, and limitations in daily activities and social participation. The disease affects not only the child but also the whole family. The family is expected to adhere to an often very laborious regimen over a long period of time. However, the parental role is incoherently conceptualized in the research field. Pain in JIA is of somatic origin, but psychosocial factors, such as mood and self-efficacy, are critical in the perception of pain and in its impact on functioning. This study examined the factors correlating and possibly explaining pain in JIA, with a special emphasis on the mutual relations between parent- and patient-driven variables. In this patient series pain was not associated with the disease activity. The degree of pain was on average fairly low in children with JIA. When the children were clustered according to age, anxiety and depression, four distinguishable cluster groups significantly associated with pain emerged. One of the groups was described by concept vulnerability because of unfavorable variable associations. Parental depressive and anxiety symptoms accompanied by illness management had a predictive power in discriminating groups of children with varying distress levels. The parent’s and child’s perception of a child’s functional capability, distress, and somatic self-efficacy had independent explanatory power predicting the child’s pain. Of special interest in the current study was self-efficacy, which refers to the belief of an individual that he/she has the ability to engage in the behavior required for tackling the disease. In children with JIA, strong self-efficacy was related to lower levels of pain, depressive symptoms and trait anxiety. This suggests strengthening a child’s sense of self-efficacy, when helping the child to cope with his or her disease. Pain experienced by a child with JIA needs to be viewed in a multidimensional bio-psycho-social context that covers biological, environmental and cognitive behavioral mechanisms. The relations between the parent-child variables are complex and affect pain both directly and indirectly. Developing pain-treatment modalities that recognize the family as a system is also warranted.

Alfven surface waves along a cylindrical plasma column surrounded by neutral gas

The dispersion characteristics of Alfven surface waves along a cylindrical plasma column insulated by a neutral gas are discussed. There is no qualitative change in the characteristic curves below the critical magnetic field, given by vA approximately=s, as compared to the propagation of surface waves along the plasma-plasma interface. For magnetic fields above this critical value, there exists a cut-off wave number kc, which depends upon the azimuthal wave number, the radius of the cylinder, the strength of the magnetic field above the critical value and the gas pressure, such that surface waves do not exist for kcolumn.

The con-stitutional re-cognition (s)cam-pain: The campaign for the hidden recognition of first nations peoples' racial inferiority

The constitutional recognition campaign has received party-wide support and its efforts have been promoted by Prime Minister Tony Abbott as being something that would ‘complete our Constitution.’ The broader rhetoric surrounding this campaign suggests that it will result in a just, albeit delayed, recognition of indigenous peoples in the Australian legal system. However, beneath the surface of this seemingly benevolent gesture, is a reaffirmation of the colonial subordination and erasure of the several hundred original nations’ peoples and ways of being.

Acoustic-surface-wave generation along a cylindrical plasma column surrounded by a compressible gas

Acoustic surface waves can be generated along the plasma column in pressure equilibrium with a gas blanket in the presence of the uniform axial magnetic field. Unlike the case of volume-acoustic-wave generation in the magnetoplasma reported recently, the threshold magnetic field required for the generation of acoustic surface waves increases with increasing gas pressure.

Purification of Antibodies Specific to a Dinucleotide Using the Hapten Bound to Deae Cellulose as an Affinity Column

The dinucleotide dpTpA held electrostatically on DEAE cellulose was used as an affinity column for the purification of dpTpA specific antibodies. Chromatography of the y-globulin fraction from dpTpA specific antisera on this column resulted in the retention of dpTpA specific antibodies which were later eluted along with the bound dpTpA using 1M NaC1. Dextran coated charcoal was the method of choice for the dissociation and removal of dpTpA bound to the antibodies. This method may extend itself to the purification of antibodies specific for other oligonucleotides.

Management of pain associated with bull castration

There is a need to have infertile male cattle in the Australian beef herd. There is, currently, no non-invasive alternative to the castration of cattle, nor is there likely to be one in the near future. There is ample scientific evidence demonstrating that castration causes stress and pain, and with the community increasingly scrutinising farming practices and seeking assurance that they are humane, there is a clear need to develop practical strategies for minimising the pain and stress associated with castration.

Pain among employees : risk factors and consequences

The overall objective of this study was to gain epidemiological knowledge about pain among employee populations. More specifically, the aims were to assess the prevalence of pain, to identify socio-economic risk groups and work-related psychosocial risk factors, and to assess the consequences in terms of health-related functioning and sickness absence. The study was carried out among the municipal employees of the City of Helsinki. Data comprised questionnaire survey conducted in years 2000-2002 and register data on sickness absence. Altogether 8960 40-60 year old employees participated to the survey (response rate 67%). Pain is common among ageing employees. Approximately 29 per cent of employees reported chronic pain and 15 per cent acute pain, and about seven per cent reported moderately or severely limiting disabling chronic pain. Pain was more common among those with lower level of education or in a low occupational class. -- Psychosocial work environment was associated with pain reports. Job strain, bullying at workplace, and problems in combining work and home duties were associated with pain among women. Among men combining work and home duties was not associated with pain, whereas organizational injustice showed associations. Pain affects functional capacity and predicts sickness absence. Those with pain reported lower level of both mental and physical functioning than those with no pain, physical functioning being more strongly affected than mental. Bodily location of pain or whether pain was acute or chronic had only minor impact on the variation in functioning, whereas the simple count of painful locations was associated with widest variation. Pain accounted for eight per cent of short term (1-3 day) sickness absence spells among men and 13 per cent among women. Of absence spells lasting between four and 14 days pain accounted for 23 per cent among women and 25 per cent among men, corresponding figures for over 14 day absence spells being 37 and 30 per cent. The association between pain and sickness absence was relatively independent of physical and psychosocial work factors, especially among women. The results of this study provide a picture of the epidemiology of pain among employees. Pain is a significant problem that seriously affects work ability. Information on risk groups can be utilized to make prevention measures more effective among those at high risk, and to decrease pain rates and thereby narrow the differences between socio-economic groups. Furthermore, the work-related psychosocial risk factors identified in this study are potentially modifiable, and it should be possible to target interventions on decreasing pain rates among employees.

Metformin for the pain in your backside?

Pain is a sensation that most people feel at some time-be it when we accidently stub our toe, or burn our hand when reaching into the oven to pull out that souffle left baking for too long.

Comparison of the reproductive ecology of two sympatric blacktip sharks (Carcharhinus limbatus and Carcharhinus tilstoni) off north-eastern Australia with species identification inferred from vertebral counts

Precaudal vertebral counts were used to distinguish between 237 morphologically similar Carcharhinus limbatus and Carcharhinus tilstoni and were congruent with differences in reproductive ecology between the species. In addition to differing lengths at maturity and adult body size, the two species had asynchronous parturition, were born at different sizes and the relative frequencies of neonates differed in two coastal nursery areas. Despite evidence that hybridization can occur, these differences suggest the species are largely reproductively isolated.

Cost and outcomes of assessing patients with chest pain in an Australian emergency department

Objectives: We sought to characterise the demographics, length of admission, final diagnoses, long-term outcome and costs associated with the population who presented to an Australian emergency department (ED) with symptoms of possible acute coronary syndrome (ACS). Design, setting and participants: Prospectively collected data on ED patients presenting with suspected ACS between November 2008 and February 2011 was used, including data on presentation and at 30 days after presentation. Information on patient disposition, length of stay and costs incurred was extracted from hospital administration records. Main outcome measures: Primary outcomes were mean and median cost and length of hospital stay. Secondary outcomes were diagnosis of ACS, other cardiovascular conditions or non-cardiovascular conditions within 30 days of presentation. Results: An ACS was diagnosed in 103 (11.1%) of the 926 patients recruited. 193 patients (20.8%) were diagnosed with other cardiovascular-related conditions and 622 patients (67.2%) had non-cardiac-related chest pain. ACS events occurred in 0 and 11 (1.9%) of the low-risk and intermediate-risk groups, respectively. Ninety-two (28.0%) of the 329 high-risk patients had an ACS event. Patients with a proven ACS, high-grade atrioventricular block, pulmonary embolism and other respiratory conditions had the longest length of stay. The mean cost was highest in the ACS group ($13 509; 95% CI, $11 794–$15 223) followed by other cardiovascular conditions ($7283; 95% CI, $6152–$8415) and non-cardiovascular conditions ($3331; 95% CI, $2976–$3685). Conclusions: Most ED patients with symptoms of possible ACS do not have a cardiac cause for their presentation. The current guideline-based process of assessment is lengthy, costly and consumes significant resources. Investigation of strategies to shorten this process or reduce the need for objective cardiac testing in patients at intermediate risk according to the National Heart Foundation and Cardiac Society of Australia and New Zealand guideline is required.

Separation of 35S-Labeled thionucleosides of Escherichia coli and Pseudomonas aeruginosa transfer RNAs on a phosphocellulose column

35S-Labeled thionucleosides prepared from Escherichia coli and Pseudomonas aeruginosa tRNAs were chromatographed separately on a phosphocellulose column with a linear salt gradient of 0.005–0.1 M ammonium formate (pH 3.9). The thionucleosides of E. coli tRNA were quantitatively separated into four peaks which were identified using authentic samples as 4-thiouridine (78 %), 2-methylthio-N6-isopentenyladenosine (8 %), 2-thiocytidine (2.5 %) and 5-methylaminomethyl-2-thiouridine (11.5 %). In the case of P. aeruginosa tRNA four radioactive thionucleoside peaks were also observed. One major difference was the almost complete absence of 2-methylthio-N6-isopentenyladenosine and the presence of a new peak of radioactivity in the nucleosides of P. aeruginosa. The relative proportions of the various thionucleosides were found to be different in E. coli and P. aeruginosa tRNAs.

Feature - No pain, no gain: Pleasure and suffering in technologies of leidenschaft

Training for bodybuilding competition is clearly a serious business that inflicts serious demands on the competitor. Not only did Francis commit time and money to compete, but he also arguably put winning before his physical well-being—enduring pain and suffering from his injury. Bodybuilding may seem like an extreme example, but it is not the only activity in which people suffer in pursuit of their goals. Boxers fight each other in the ring; soccer players risk knee and ankle injuries, sometimes playing despite being hurt; and mountaineers risk their lives in dangerous climbs. In the arts there are many examples of people suffering to achieve their goals: Beethoven kept composing, conducting, and performing despite his hearing loss; van Gogh grappled with depression but kept painting, finding fame only posthumously; and Mozart lived the final years of his life impoverished but still composing. These examples show that many great achievements come at a price: severe suffering...

Improvement in the voltage grading (axial and radial) of the generator column of a Van de Graaf generator by the use of a resistor chain

It is well known that the use of a series of resistors, connected between the equipotential rings of a Van de Graaff generator, improves the axial voltage grading of the generator. The work reported in this paper shows how the resistor chain also improves the radial voltage gradient. The electrolytic field mapping technique was adopted in the present work.