Deformities of the spine

Deformities of the spine occur as a consequence of a number of different aetiologies each with a differing pathogenesis and natural history. The resulting deformity may be a scoliosis which is a lateral curvature of the spine in the frontal plane, a kyphosis which is an abnormal posterior curvature in the sagittal plane or a kyphoscoliosis which is a combination of both deformities. Significant progression of the curvature can occur with spinal growth and result in a very severe deformity with a major effect on general health, longevity and quality of life. If the deformity develops and progresses in early childhood, it can result in an impairment of lung growth and development possibly leading to cor pulmonale and death in early adult life. A kyphosis or kyphoscoliosis can cause spinal cord compression and if left untreated can result in paraplegia. Some patients develop back discomfort in later life, due to secondary degenerative arthritic changes, and others have a reduced selfimage leading to psychological disturbances. Knowledge of the natural history is essential in anticipating problems and is the benchmark by which treatment is evaluated.This collection of work is based on my studies of the aetiology, pathogenesis, natural history and management of patients with deformities of the spine seen over a period of 35 years while working as a spinal surgeon in Edinburgh.In 1975, I was appointed Senior Lecturer and Consultant Orthopaedic Spine Surgeon, working with Prof. J I P James in the Department of Orthopaedic Surgery, University of Edinburgh. It was here that I was able to establish a large database of patients, especially those with congenital deformities of the spine, who had previously received little or no treatment. This provided me with invaluable information and stimulated my lifelong interest in the natural history and allowed me to formulate an appropriate course of management for these conditions. In 1978, when Prof. James retired I took over his clinical practice and established the Edinburgh Spine Deformity Centre which later became, under my directorship, the Scottish National Spine Deformity Centre treating all patients from the whole of Scotland.At present there is virtually no severity of spinal deformity which cannot be significantly improved by surgery. However, it should be recognized that the necessity for surgical salvage procedures at a late stage, to correct severe deformities for conditions commencing as minor curves in infancy or adolescence, indicates a failure of management. This thesis emphasizes the need for early detection and prevention of severe deformity and depends on a thorough knowledge of the pathogenesis and natural history of the various conditions which can produce a scoliosis, kyphosis or kyphoscoliosis

SAGE 1 data user's guide

A guide for using the data products from the Stratospheric Aerosol and Gas Experiment 1 (SAGE 1) for scientific investigations of stratospheric chemistry related to aerosol, ozone, nitrogen dioxide, dynamics, and climate change is presented. A detailed description of the aerosol profile tape, the ozone profile tape, and the nitrogen dioxide profile tape is included. These tapes are the SAGE 1 data products containing aerosol extinction data and ozone and nitrogen dioxide concentration data for use in the different scientific investigations. Brief descriptions of the instrument operation, data collection, processing, and validation, and some of the scientific analyses that were conducted are also included

Spectral radiometry and tropospheric aerosols: Report of panel

The term aerosols, as used here, refers to the haze, smoke, and dust that appear in the troposphere. The term does not refer to the hydrometeors in cumulus and stratus clouds but does include the sulfuric acid-water droplets which are assumed to predominate in the stratospheric aerosol layer. The aerosol properties that were measured from satellites and those which can be made in the near term (up to 1992) will be reviewed. The capabilities that will exist in the years 1992 to 2000, with implementation of EOS, are then discussed. Finally, a few words will be said concerning the potential for aerosol measurements for the decade after 2000

Design considerations for light weight mechanical parts

Context and Background - Lightweight design is important for many engineering fields due to the increased energy efficiency and process performance that it can result in. Functionally graded materials (FGMs) give a key contribution to lightweight design when low mass along with a gradual change in a second primary constraint is required such as alleviation of a large temperature gradient. With the evolution of additive manufacturing (AM), FGM use for light weighting is rising in practicality. Therefore, research into combining FGMs with AM is required, and should include topics relevant to these, including form, material choice and structural design. The work is tested on robotic arm links due to the ever-increasing adoption of automation, and the practical accessibility of them for the researcher. Aim of Research - The aim of the research is to investigate the mass reduction of robotic arm links by merging second moment of area calculations, structured cells, topology optimisation, functionally graded materials and additive manufacture in various combinations. Key Work - The main output of this work is a set of design guidelines that have been written to assist engineers with combining FGMs, topology optimisation, structured cells and high-level AM restrictions. Within the field of lightweight design, the guidelines are use-case agnostic. The design guidelines have been trialled using test cases, each aimed at individual elements of the guidelines. The objective of the first test case is to discover if FGMs will reduce stresses in parts constructed of dissimilar materials when used in conjunction with high-level AM constraints. The second test case trails the various computational testing sections required in the guidelines, including part sectioning rules and material distribution techniques. The third test case incorporates heat ow simulation during AM deposition of the FGMs, including the three heat transfer mechanisms and interaction with the print bed of AM hardware. The final test case assesses the entirety of the design guidelines, re-examining the aspects tested in the second and third test cases, together with a technique to decide whether structured cells or topology optimisation should be used based on the use case of the part, and a first pass at inspecting the residual stresses in the additively manufactured part once it has cooled. Conclusions - Overall, the use of FGMs along with lightweight structural design techniques and high-level AM restrictions are computationally successful at reducing the mass in robotic arm links. While the design guidelines are use case agnostic, they make most sense used in fields of engineering that have a substantial requirement for light weight design, such as aerospace and space. Ideally, physical testing would have been used to increase validity of the design guidelines. Unfortunately, funds were not available, and thus physical testing is deemed the next step for this work in the future.Context and Background - Lightweight design is important for many engineering fields due to the increased energy efficiency and process performance that it can result in. Functionally graded materials (FGMs) give a key contribution to lightweight design when low mass along with a gradual change in a second primary constraint is required such as alleviation of a large temperature gradient. With the evolution of additive manufacturing (AM), FGM use for light weighting is rising in practicality. Therefore, research into combining FGMs with AM is required, and should include topics relevant to these, including form, material choice and structural design. The work is tested on robotic arm links due to the ever-increasing adoption of automation, and the practical accessibility of them for the researcher. Aim of Research - The aim of the research is to investigate the mass reduction of robotic arm links by merging second moment of area calculations, structured cells, topology optimisation, functionally graded materials and additive manufacture in various combinations. Key Work - The main output of this work is a set of design guidelines that have been written to assist engineers with combining FGMs, topology optimisation, structured cells and high-level AM restrictions. Within the field of lightweight design, the guidelines are use-case agnostic. The design guidelines have been trialled using test cases, each aimed at individual elements of the guidelines. The objective of the first test case is to discover if FGMs will reduce stresses in parts constructed of dissimilar materials when used in conjunction with high-level AM constraints. The second test case trails the various computational testing sections required in the guidelines, including part sectioning rules and material distribution techniques. The third test case incorporates heat ow simulation during AM deposition of the FGMs, including the three heat transfer mechanisms and interaction with the print bed of AM hardware. The final test case assesses the entirety of the design guidelines, re-examining the aspects tested in the second and third test cases, together with a technique to decide whether structured cells or topology optimisation should be used based on the use case of the part, and a first pass at inspecting the residual stresses in the additively manufactured part once it has cooled. Conclusions - Overall, the use of FGMs along with lightweight structural design techniques and high-level AM restrictions are computationally successful at reducing the mass in robotic arm links. While the design guidelines are use case agnostic, they make most sense used in fields of engineering that have a substantial requirement for light weight design, such as aerospace and space. Ideally, physical testing would have been used to increase validity of the design guidelines. Unfortunately, funds were not available, and thus physical testing is deemed the next step for this work in the future

Reconfiguring economic democracy: generating new forms of collective agency, individual economic freedom and public participation

We seek to advance debate and thinking about economic democracy. While recognising the importance of existing approaches focused upon collective bargaining and workplace organisation, we articulate a perspective that emphasises the importance of individual economic rights, capabilities and freedoms at a time when established norms and protections at work are in retreat in many parts of the world. We outline a framework where both individual rights to self-government of one’s own labour, as well as the right of all citizens to participate in economic decision-making, are emphasised. The framework identifies a set of underlying principles, prerequisites, critical spheres for intervention, progressive institutional arrangements, and policies in pursuit of an expanded agenda around economic democracy. In this way, economic democracy potentially empowers individuals and creates the basis for generating new and sustainable alliances that challenge elite dominance in contemporary capitalism

Placental Structure in Preterm Birth Among HIV-Positive Versus HIV-Negative Women in Kenya.

BackgroundPreterm birth (PTB) is a major cause of infant morbidity and mortality in developing countries. Recent data suggest that in addition to Human Immunodeficiency Virus (HIV) infection, use of antiretroviral therapy (ART) increases the risk of PTB. As the mechanisms remain unexplored, we conducted this study to determine whether HIV and ART were associated with placental changes that could contribute to PTB.SettingWe collected and evaluated placentas from 38 HIV-positive women on ART and 43 HIV-negative women who had preterm deliveries in Nairobi, Kenya.MethodsAnatomical features of the placentas were examined at gross and microscopic levels. Cases were matched for gestational age and compared by the investigators who were blinded to maternal HIV serostatus.ResultsAmong preterm placentas, HIV infection was significantly associated with thrombosis (P = 0.001), infarction (P = 0.032), anomalies in cord insertion (P = 0.02), gross evidence of membrane infection (P = 0.043), and reduced placental thickness (P = 0.010). Overall, preterm placentas in both groups were associated with immature villi, syncytial knotting, villitis, and deciduitis. Features of HIV-positive versus HIV-negative placentas included significant fibrinoid deposition with villus degeneration, syncytiotrophoblast delamination, red blood cell adhesion, hypervascularity, and reduction in both surface area and perimeter of the terminal villi.ConclusionsThese results imply that HIV infection and/or ART are associated with morphological changes in preterm placentas that contribute to delivery before 37 weeks. Hypervascularity suggests that the observed pathologies may be attributable, in part, to hypoxia. Further research to explore potential mechanisms will help elucidate the pathways that are involved perhaps pointing to interventions for decreasing the risk of prematurity among HIV-positive women

Gait biofeedback training in people with Parkinson’s disease : A pilot study

Background People with Parkinson’s disease (PD) are at a high risk of falls, with ~ 60% experiencing a fall each year. Greater mediolateral head and pelvis motion during gait are known to increase the risk of falling in PD, however the ability to modify these aspects of gait has not been examined. Thus, this study aimed to examine whether mediolateral trunk, head and pelvis motion during walking could be successfully decreased in people with PD using real-time biofeedback. Methods Participants were provided with real-time biofeedback regarding their mediolateral trunk lean via a visual projection whilst walking along an 8-m indoor walkway. Using the feedback provided, they were asked to reduce the magnitude of their mediolateral trunk lean. Gait was recorded for four conditions (i) Baseline, (ii) Intervention, (iii) immediately Post-Intervention, and (iv) 1-week Follow-Up. Biomechanical variables associated with falls risk were compared between conditions, including normalised mediolateral motion, gait velocity and stride length. Results A reduction in mediolateral trunk lean, step length and gait velocity from Baseline to the Intervention and Post-intervention conditions was observed. Contrary to this, increased normalised ML pelvis and trunk motion was observed between the Baseline and Intervention conditions, but returned to Baseline levels in the Post-Intervention condition. Conclusions Results from the current study suggest that real-time visual biofeedback may be effective at modifying specific gait characteristics that are associated with falls in PD. Further research is required to better understand the influence of this intervention approach on falls incidence. Trial registration Australian New Zealand Clinical Trials Registry ACTRN12620000994987. Registered 10 June 2020 - Retrospectively registered, https://anzctr.org.au/Trial/Registration/TrialReview.aspx?id=38032

The surgical management of congenital kyphosis and kyphoscoliosis

Study Design. A retrospective study of surgery for congenital kyphosis and kyphoscoliosis. Objective, To assess the effectiveness of different types of spine surgery in the management of congenital kyphosis and kyphoscoliosis. Summary of Background Data. Congenital kyphosis and kyphoscoliosis are much less common than congenital scoliosis but potentially more serious, because these curves can progress rapidly and Type I deformities can lead to spinal cord compression and paraplegia. No one operative procedure can be applied to all types and sizes of deformity. The method of surgical treatment depends on the age of the patient, the type and size of the deformity, and the presence or absence of spinal cord compression causing a neurologic deficit, Methods. Sixty-five patients with a congenital kyphosis (n=14) or kyphoscoliosis (n=51) were treated by five different methods of spine arthrodesis: prophylactic posterior arthrodesis before age of 5 years (n=11), posterior arthrodesis after age 5 years without instrumentation (n=26) and with instrumentation (n=12), combined anterior and posterior arthrodesis without instrumentation (n=7) and with instrumentation (n=9). Six patients had preoperative lower limb spastic paraparesis caused by spinal cord compression. The mean age at surgery was 9 years 6 months (range, 11 months to 25 years), and all 65 patients were observed for a minimum of 2 years (mean 6 years 6 months, range 2 to 18 years). Fifty-seven patients reached skeletal maturity. Results. A posterior arthrodesis performed before the age of 5 years resulted in a gradual reduction of the kyphosis by a mean 15° in 9 of the 11 patients, followed up for a mean of 11 years, whose initial kyphosis was less than 55°. Patients treated after the age of 5 years by a posterior arthrodesis followed by cast application had poor correction and a high incidence of pseudarthrosis. This was not significantly improved by the addition of posterior instrumentation. For curves greater than 60°, the most successful results were achieved by an anterior spinal release and arthrodesis with strut graft correction followed by posterior arthrodesis with instrumentation (if possible). Conclusion, All patients with a Type I or Type III congenital kyphosis or kyphoscoliosis should be treated by a posterior arthrodesis before the age of 5 years and before the kyphosis exceeds 50°. A kyphosis that does not reduce to less than 50° as measured on the lateral spine radiograph made with the patient supine requires an anterior release and arthrodesis with strut grafting followed by posterior arthrodesis with instrumentation (if possible)

Planet Four: Terrains - Discovery of Araneiforms Outside of the South Polar Layered Deposits

We present the results of a systematic mapping of seasonally sculpted terrains on the South Polar region of Mars with the Planet Four: Terrains (P4T) online citizen science project. P4T enlists members of the general public to visually identify features in the publicly released Mars Reconnaissance Orbiter CTX images. In particular, P4T volunteers are asked to identify: 1) araneiforms (including features with a central pit and radiating channels known as 'spiders'); 2) erosional depressions, troughs, mesas, ridges, and quasi-circular pits characteristic of the South Polar Residual Cap (SPRC) which we collectively refer to as 'Swiss cheese terrain', and 3) craters. In this work we present the distributions of our high confidence classic spider araneiforms and Swiss cheese terrain identifications. We find no locations within our high confidence spider sample that also have confident Swiss cheese terrain identifications. Previously spiders were reported as being confined to the South Polar Layered Deposits (SPLD). Our work has provided the first identification of spiders at locations outside of the SPLD, confirmed with high resolution HiRISE imaging. We find araneiforms on the Amazonian and Hesperian polar units and the Early Noachian highland units, with 75% of the identified araneiform locations in our high confidence sample residing on the SPLD. With our current coverage, we cannot confirm whether these are the only geologic units conducive to araneiform formation on the Martian South Polar region. Our results are consistent with the current CO2 jet formation scenario with the process exploiting weaknesses in the surface below the seasonal CO2 ice sheet to carve araneiform channels into the regolith over many seasons. These new regions serve as additional probes of the conditions required for channel creation in the CO2 jet process. (Abridged)Comment: accepted to Icarus - Supplemental data files are available at https://www.zooniverse.org/projects/mschwamb/planet-four-terrains/about/results - Icarus print version available at http://www.sciencedirect.com/science/article/pii/S001910351730055

The Agricultural Health Study: Factors Affecting Completion and Return of Self-Administered Questionnaires in a Large Prospective Cohort Study of Pesticide Applicators

Response rates were examined in a prospective epidemiologic study of individuals, mostly farmers, from Iowa and North Carolina seeking a pesticide applicator license during the period from 1994 through 1996. In the first year of enrollment 16,535 farmers (representing 77% of eligible farmer applicators) enrolled in the study by completing a 17-page questionnaire administered at a pesticide training session; 47% of the enrolled farmers completed and returned a much longer take-home questionnaire. The characteristics of farmers who completed only the enrollment questionnaire were quite similar to those of farmers who also completed and returned the take-home questionnaire. The most notable difference was the increased age of responders. Thus, the study population might have slightly higher cumulative farm exposures and slightly lower current farm exposures than the base population of all farmer applicators. The lack of evidence for substantial selection bias is reassuring for the Agricultural Health Study, and provides a measure of reassurance for other studies depending on the voluntary completion of self-administered questionnaires