Optical surface generation in ultra-precision polishing of freeform

2009-2010 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

Effect of an Injury Awareness Education Program on Risk-Taking Behaviors and Injuries in Juvenile Justice Offenders: A Retrospective Cohort Study

Background Risk-taking behavior is a leading cause of injury and death amongst young people. Methodology and Principal Findings This was a retrospective cohort study on the effectiveness of a 1-day youth injury awareness education program (Prevent Alcohol and Risk-related Trauma in Youth, P.A.R.T.Y.) program in reducing risk taking behaviors and injuries of juvenille justice offenders in Western Australia. Of the 3659 juvenile justice offenders convicted by the court magistrates between 2006 and 2010, 225 were referred to the P.A.R.T.Y. education program. In a before and after survey of these 225 participants, a significant proportion of them stated that they were more receptive to modifying their risk-taking behavior (21% before vs. 57% after). Using data from the Western Australia Police and Department of Health, the incidence of subsequent offences and injuries of all juvenile justice offenders was assessed. The incidence of subsequent traffic or violence-related offences was significantly lower for those who had attended the program compared to those who did not (3.6% vs. 26.8%; absolute risk reduction [ARR] = 23.2%, 95% confidence interval [CI] 19.9%–25.8%; number needed to benefit = 4.3, 95%CI 3.9–5.1; p = 0.001), as were injuries leading to hospitalization (0% vs. 1.6% including 0.2% fatality; ARR = 1.6%, 95%CI 1.2%–2.1%) and alcohol or drug-related offences (0% vs. 2.4%; ARR 2.4%, 95%CI 1.9%–2.9%). In the multivariate analysis, only P.A.R.T.Y. education program attendance (odds ratio [OR] 0.10, 95%CI 0.05–0.21) and a higher socioeconomic background (OR 0.97 per decile increment in Index of Relative Socioeconomic Advantage and Disadvantage, 95%CI 0.93–0.99) were associated with a lower risk of subsequent traffic or violence-related offences. Significance Participation in an injury education program involving real-life trauma scenarios was associated with a reduced subsequent risk of committing violence- or traffic-related offences, injuries, and death for juvenille justice offenders

Transmutations and spectral parameter power series in eigenvalue problems

We give an overview of recent developments in Sturm-Liouville theory concerning operators of transmutation (transformation) and spectral parameter power series (SPPS). The possibility to write down the dispersion (characteristic) equations corresponding to a variety of spectral problems related to Sturm-Liouville equations in an analytic form is an attractive feature of the SPPS method. It is based on a computation of certain systems of recursive integrals. Considered as families of functions these systems are complete in the $L_{2}$-space and result to be the images of the nonnegative integer powers of the independent variable under the action of a corresponding transmutation operator. This recently revealed property of the Delsarte transmutations opens the way to apply the transmutation operator even when its integral kernel is unknown and gives the possibility to obtain further interesting properties concerning the Darboux transformed Schr\"{o}dinger operators. We introduce the systems of recursive integrals and the SPPS approach, explain some of its applications to spectral problems with numerical illustrations, give the definition and basic properties of transmutation operators, introduce a parametrized family of transmutation operators, study their mapping properties and construct the transmutation operators for Darboux transformed Schr\"{o}dinger operators.Comment: 30 pages, 4 figures. arXiv admin note: text overlap with arXiv:1111.444

Cognitive skills and literacy performance of Chinese adolescents with and without dyslexia

The present study sought to identify cognitive abilities that might distinguish Hong Kong Chinese adolescents with dyslexia and to assess how these abilities were associated with Chinese word reading, word dictation, and reading comprehension. The cognitive skills of interest were morphological awareness, visual-orthographic knowledge, rapid naming, and verbal working memory. A total of 90 junior secondary school students, 30 dyslexic, 30 chronological age controls, and 30 reading level controls was tested on a range of cognitive and literacy tasks. Dyslexic students were less competent than the control students in all cognitive and literacy measures. The regression analyses also showed that verbal working memory, rapid naming, morphological awareness, and visual-orthographic knowledge were significantly associated with literacy performance. Findings underscore the importance of these cognitive skills for Chinese literacy acquisition. Overall, this study highlights the persistent difficulties of Chinese dyslexic adolescents who seem to have multiple causes for reading and spelling difficulties

The phases of deuterium at extreme densities

We consider deuterium compressed to higher than atomic, but lower than nuclear densities. At such densities deuterium is a superconducting quantum liquid. Generically, two superconducting phases compete, a "ferromagnetic" and a "nematic" one. We provide a power counting argument suggesting that the dominant interactions in the deuteron liquid are perturbative (but screened) Coulomb interactions. At very high densities the ground state is determined by very small nuclear interaction effects that probably favor the ferromagnetic phase. At lower densities the symmetry of the theory is effectively enhanced to SU(3), and the quantum liquid enters a novel phase, neither ferromagnetic nor nematic. Our results can serve as a starting point for investigations of the phase dynamics of deuteron liquids, as well as exploration of the stability and dynamics of the rich variety of topological objects that may occur in phases of the deuteron quantum liquid, which range from Alice strings to spin skyrmions to Z_2 vortices.Comment: 9 pages, 6 figures; v2: fixed typo

Guillain-Barré syndrome: a century of progress

In 1916, Guillain, Barré and Strohl reported on two cases of acute flaccid paralysis with high cerebrospinal fluid protein levels and normal cell counts — novel findings that identified the disease we now know as Guillain–Barré syndrome (GBS). 100 years on, we have made great progress with the clinical and pathological characterization of GBS. Early clinicopathological and animal studies indicated that GBS was an immune-mediated demyelinating disorder, and that severe GBS could result in secondary axonal injury; the current treatments of plasma exchange and intravenous immunoglobulin, which were developed in the 1980s, are based on this premise. Subsequent work has, however, shown that primary axonal injury can be the underlying disease. The association of Campylobacter jejuni strains has led to confirmation that anti-ganglioside antibodies are pathogenic and that axonal GBS involves an antibody and complement-mediated disruption of nodes of Ranvier, neuromuscular junctions and other neuronal and glial membranes. Now, ongoing clinical trials of the complement inhibitor eculizumab are the first targeted immunotherapy in GBS

The effect of arm training on thermoregulatory responses and calf volume during upper body exercise

The final publication is available at Springer via https://doi.org/10.1007/s00421-014-2842-9.PURPOSE: The smaller muscle mass of the upper body compared to the lower body may elicit a smaller thermoregulatory stimulus during exercise and thus produce novel training-induced thermoregulatory adaptations. Therefore, the principal aim of the study was to examine the effect of arm training on thermoregulatory responses during submaximal exercise. METHODS: Thirteen healthy male participants (Mean ± SD age 27.8 ± 5.0 years, body mass 74.8 ± 9.5 kg) took part in 8 weeks of arm crank ergometry training. Thermoregulatory and calf blood flow responses were measured during 30 min of arm cranking at 60% peak power (W peak) pre-, and post-training and post-training at the same absolute intensity as pre-training. Core temperature and skin temperatures were measured, along with heat flow at the calf, thigh, upper arm and chest. Calf blood flow using venous occlusion plethysmography was performed pre- and post-exercise and calf volume was determined during exercise. RESULTS: The upper body training reduced aural temperature (0.1 ± 0.3 °C) and heat storage (0.3 ± 0.2 J g(-1)) at a given power output as a result of increased whole body sweating and heat flow. Arm crank training produced a smaller change in calf volume post-training at the same absolute exercise intensity (-1.2 ± 0.8% compared to -2.2 ± 0.9% pre-training; P < 0.05) suggesting reduced leg vasoconstriction. CONCLUSION: Training improved the main markers of aerobic fitness. However, the results of this study suggest arm crank training additionally elicits physiological responses specific to the lower body which may aid thermoregulation.Peer reviewedFinal Accepted Versio

No difference in stroke knowledge between Korean adherents to traditional and western medicine – the AGE study: an epidemiological study

BACKGROUND: Effective stroke intervention and risk reduction depend on the general public's awareness and knowledge of stroke. In Korea, where both traditional Oriental medicine and Western medicine are practiced, estimates of the general public's awareness and knowledge of stroke are poor. The present study sought to describe the inception cohort of the Ansan Geriatric Study (AGE study) and to determine baseline stroke awareness and preferred medical treatment for stroke in this Korean sample. METHODS: A total of 2,767 subjects selected randomly from the Ansan Geriatric Study in South Korea were questioned about stroke. Their answers were compared with their sociodemographic data and other variables. RESULTS: Only 44.8% of participants correctly identified stroke as a vascular disease in the human brain. Sudden numbness or weakness was the most frequently identified stroke warning sign (60.2%). Hypertension (66.7%) and mental stress (62.2%) were most frequently identified as stroke risk factors. The contributions of diabetes mellitus and cardiovascular disease to stroke were underestimated; they were identified as risk factors by 28.3% and 18.6% of participants, respectively. The predictors for poor knowledge of stroke warning signs and risk factors were similar irrespective of preference for Western or Oriental medical treatment, and included those with lower levels of education and inaccurate definition of stroke. Television and radio (40.3%) were the most frequent sources of stroke information for both groups. CONCLUSION: This study shows that knowledge of stroke is similar among Koreans with preferences for either Western or Oriental medical treatment and that misunderstandings about stroke are common among the Korean elderly. In order to prevent and manage stroke effectively, public health education regarding basic concepts of stroke is necessary. This should target those with a lower level of education and a misunderstanding of the definition of stroke

The Risk of Stroke after Percutaneous Vertebroplasty for Osteoporosis: A Population-Based Cohort Study

PURPOSE: To investigate the incidence and risk of stroke after percutaneous vertebroplasty in patients with osteoporosis. METHODS: A group of 334 patients with osteoporosis, and who underwent percutaneous vertebroplasty during the study period, was compared to 1,655 age-, sex- and propensity score-matched patients who did not undergo vertebroplasty. All demographic covariates and co-morbidities were deliberately matched between the two groups to avoid selection bias. Every subject was followed-up for up to five years for stroke. Adjustments using a Cox regression model and Kaplan-Meier analyses were conducted. RESULTS: A total of 1,989 osteoporotic patients were followed up for 3,760.13 person-years. Overall, the incidence rates of any stroke, hemorrhagic stroke and ischemic stroke were 22.6, 4.2 and 19.6 per 1,000 person-years, respectively. Patients who underwent vertebroplasty were not more likely to have any stroke (crude hazard ratio = 1.13, p = 0.693), hemorrhagic stroke (HR = 2.21, p = 0.170), or ischemic stroke (HR = 0.96, p = 0.90). After adjusting for demographics, co-morbidities and medications, the vertebroplasty group had no significant difference with the comparison group in terms of any, hemorrhagic and ischemic strokes (adjusted HR = 1.22, 3.17, and 0.96, p = 0.518, 0.055, and 0.91, respectively). CONCLUSIONS: Osteoporotic patients who undergo percutaneous vertebroplasty are not at higher risk of any stroke in the next five years after the procedure

Functional Remineralization of Dentin Lesions Using Polymer-Induced Liquid-Precursor Process

It was hypothesized that applying the polymer-induced liquid-precursor (PILP) system to artificial lesions would result in time-dependent functional remineralization of carious dentin lesions that restores the mechanical properties of demineralized dentin matrix. 140 µm deep artificial caries lesions were remineralized via the PILP process for 7–28 days at 37°C to determine temporal remineralization characteristics. Poly-L-aspartic acid (27 KDa) was used as the polymeric process-directing agent and was added to the remineralization solution at a calcium-to-phosphate ratio of 2.14 (mol/mol). Nanomechanical properties of hydrated artificial lesions had a low reduced elastic modulus (ER = 0.2 GPa) region extending about 70 μm into the lesion, with a sloped region to about 140 μm where values reached normal dentin (18–20 GPa). After 7 days specimens recovered mechanical properties in the sloped region by 51% compared to the artificial lesion. Between 7–14 days, recovery of the outer portion of the lesion continued to a level of about 10 GPa with 74% improvement. 28 days of PILP mineralization resulted in 91% improvement of ER compared to the artificial lesion. These differences were statistically significant as determined from change-point diagrams. Mineral profiles determined by micro x-ray computed tomography were shallower than those determined by nanoindentation, and showed similar changes over time, but full mineral recovery occurred after 14 days in both the outer and sloped portions of the lesion. Scanning electron microscopy and energy dispersive x-ray analysis showed similar morphologies that were distinct from normal dentin with a clear line of demarcation between the outer and sloped portions of the lesion. Transmission electron microscopy and selected area electron diffraction showed that the starting lesions contained some residual mineral in the outer portions, which exhibited poor crystallinity. During remineralization, intrafibrillar mineral increased and crystallinity improved with intrafibrillar mineral exhibiting the orientation found in normal dentin or bone