Application of the x-ray measurement model to image processing of x-ray radiographs

A computational model has been developed at which simulates the film response to the interaction of x-rays with a sample[1,2]. By using a CAD model as a virtual part, film densities of the radiograph are predicted. The number of photons which reach the film is based on the thickness of the part, part geometry, and the material absorption coefficient. Also taken into consideration are the x-ray beam characteristics, film properties, and the experimental configuration. The model generated images can vary in size and resolution, depending on the user chosen parameters. Noise is calculated using a Gaussian noise distribution and adjusted for the film type. The result of this simulation is a two-dimensional numerically generated digital image, which represents a radiograph of the part. This result can be used to analyze the flaws in an actual radiograph with the same set-up and exposure parameters

Do bone mineral content and density determine fracture in children? A possible threshold for physical activity

BackgroundRelations between bone parameters, physical exertion, and childhood fractures are complex. We aimed to estimate the associations between fracture history and bone mineral content (BMC) and areal bone mineral density (aBMD) at 7 years of age, by levels of physical activity, as a proxy for trauma frequency.MethodsWe used data collected from 2,261 children of the Generation XXI birth cohort, assembled in 2005/6 in Porto, Portugal. At the age of 7 years (2012/4), fracture history, time spent per week in active play, and sports practice were reported by parents. Subtotal and lumbar spine (LS) BMC and aBMD were measured using whole-body dual-energy X-ray absorptiometry.ResultsBoys and girls in the highest categories of time spent in sports practice or active play generally had higher BMC and aBMD. Among girls, BMC and aBMD were protective of fracture only in the highest quarter of active play (>660 min/week)-odds ratios (OR; 95% confidence interval (95% CI)) for subtotal BMC=0.27 (0.11-0.67), subtotal aBMD=0.18 (0.06-0.49), and LS aBMD=0.41 (0.22-0.75). For boys in the highest quarter of sports practice (>240 min/week), subtotal and LS BMC were protective of fracture-OR=0.39 (0.16-0.98) and 0.51 (0.27-0.96), respectively.ConclusionIn prepubertal children, BMC and aBMD predicted fracture history only in the highest levels of physical activity.info:eu-repo/semantics/publishedVersio

Day occupation is associated with psychopathology for adolescents and young adults with Down syndrome

Background: Young adults with Down syndrome experience increased rates of emotional and behavioural problems compared with the general population. Most adolescents with Down syndrome living in Western Australia participate in sheltered employment as their main day occupation. Relationship between day occupation and changes in behaviour has not been examined. Therefore, the aim of this research was to explore any relationship between post school day occupations and changes in the young person’s behaviour. Methods: The Down syndrome Needs Opinion Wishes database was used for case ascertainment of young adults aged 15 to 32 years with Down syndrome. Families of 118 young people in this population-based database completed questionnaires in 2004, 2009 and 2011. The questionnaires addressed both young person characteristics such as age, gender, presence of impairments, behaviour, functioning in activities of daily living, and family characteristics such as income and family functioning. Post-school day occupations in which the young people were participating included open and sheltered employment, training and day recreation programs. Change in behaviour of young adults who remained in the same post-school day occupation from 2009 to 2011 (n = 103) were examined in a linear regression model adjusting for confounding variables including age, gender, prior functioning and behaviour in 2004 and family income.Results: In comparison to those young adults attending open employment from 2009 to 2011, those attending day recreation programs were reported to experience worsening in behaviour both in the unadjusted (effect size -0.14, 95% CI -0.24, -0.05) and adjusted models (effect size -0.15, 95% CI -0.29, -0.01). Conclusions: We found that the behaviour of those participating in open employment improved compared to those attending other day occupations. Further examination of the direction of this association is required

Interacting Supernovae: Types IIn and Ibn

Supernovae (SNe) that show evidence of strong shock interaction between their ejecta and pre-existing, slower circumstellar material (CSM) constitute an interesting, diverse, and still poorly understood category of explosive transients. The chief reason that they are extremely interesting is because they tell us that in a subset of stellar deaths, the progenitor star may become wildly unstable in the years, decades, or centuries before explosion. This is something that has not been included in standard stellar evolution models, but may significantly change the end product and yield of that evolution, and complicates our attempts to map SNe to their progenitors. Another reason they are interesting is because CSM interaction is an efficient engine for making bright transients, allowing super-luminous transients to arise from normal SN explosion energies, and allowing transients of normal SN luminosities to arise from sub-energetic explosions or low radioactivity yield. CSM interaction shrouds the fast ejecta in bright shock emission, obscuring our normal view of the underlying explosion, and the radiation hydrodynamics of the interaction is challenging to model. The CSM interaction may also be highly non-spherical, perhaps linked to binary interaction in the progenitor system. In some cases, these complications make it difficult to definitively tell the difference between a core-collapse or thermonuclear explosion, or to discern between a non-terminal eruption, failed SN, or weak SN. Efforts to uncover the physical parameters of individual events and connections to possible progenitor stars make this a rapidly evolving topic that continues to challenge paradigms of stellar evolution.Comment: Final draft of a chapter in the "SN Handbook". Accepted. 25 pages, 3 fig

Evaluating the quality of interaction between medical students and nurses in a large teaching hospital

BACKGROUND: Effective health care depends on multidisciplinary collaboration and teamwork, yet little is known about how well medical students and nurses interact in the hospital environment, where physicians-in-training acquire their first experiences as members of the health care team. The objective of this study was to evaluate the quality of interaction between third-year medical students and nurses during clinical rotations. METHODS: We surveyed 268 Indiana University medical students and 175 nurses who worked at Indiana University Hospital, the School's chief clinical training site. The students had just completed their third year of training. The survey instrument consisted of 7 items that measured "relational coordination" among members of the health care team, and 9 items that measured psychological distress. RESULTS: Sixty-eight medical students (25.4%) and 99 nurses (56.6%) completed the survey. The relational coordination score (ranked 1 to 5, low to high), which provides an overall measure of interaction quality, showed that medical students interacted with residents the best (4.16) and with nurses the worst (2.98; p < 0.01). Conversely, nurses interacted with other nurses the best (4.36) and with medical students the worst (2.68; p < 0.01). Regarding measures of psychological distress (ranked 0 to 4, low to high), the interpersonal sensitivity score of medical students (1.56) was significantly greater than that of nurses (1.03; p < 0.01), whereas the hostility score of nurses (0.59) was significantly greater than that of medical students (0.39; p < 0.01). CONCLUSION: The quality of interaction between medical students and nurses during third-year clinical rotations is poor, which suggests that medical students are not receiving the sorts of educational experiences that promote optimal physician-nurse collaboration. Medical students and nurses experience different levels of psychological distress, which may adversely impact the quality of their interaction

Observational and Physical Classification of Supernovae

This chapter describes the current classification scheme of supernovae (SNe). This scheme has evolved over many decades and now includes numerous SN Types and sub-types. Many of these are universally recognized, while there are controversies regarding the definitions, membership and even the names of some sub-classes; we will try to review here the commonly-used nomenclature, noting the main variants when possible. SN Types are defined according to observational properties; mostly visible-light spectra near maximum light, as well as according to their photometric properties. However, a long-term goal of SN classification is to associate observationally-defined classes with specific physical explosive phenomena. We show here that this aspiration is now finally coming to fruition, and we establish the SN classification scheme upon direct observational evidence connecting SN groups with specific progenitor stars. Observationally, the broad class of Type II SNe contains objects showing strong spectroscopic signatures of hydrogen, while objects lacking such signatures are of Type I, which is further divided to numerous subclasses. Recently a class of super-luminous SNe (SLSNe, typically 10 times more luminous than standard events) has been identified, and it is discussed. We end this chapter by briefly describing a proposed alternative classification scheme that is inspired by the stellar classification system. This system presents our emerging physical understanding of SN explosions, while clearly separating robust observational properties from physical inferences that can be debated. This new system is quantitative, and naturally deals with events distributed along a continuum, rather than being strictly divided into discrete classes. Thus, it may be more suitable to the coming era where SN numbers will quickly expand from a few thousands to millions of events.Comment: Extended final draft of a chapter in the "SN Handbook". Comments most welcom

Generic and disease-specific health related quality of life in non-cirrhotic, cirrhotic and transplanted liver patients: a cross-sectional study

BACKGROUND: Studies on Health Related Quality of Life (HRQoL) of chronic liver patients were performed in clinical populations. These studies included various disease stages but small variations in aetiology and no transplanted patients. We performed a large HRQoL study in non-cirrhotic, cirrhotic and transplanted liver patients with sufficient variety in aetiology. We compared the generic HRQoL and fatigue between liver patients and healthy controls and compared the disease-specific and generic HRQoL and fatigue between non-cirrhotic, cirrhotic and transplanted liver patients, corrected for aetiology. METHODS: Members of the Dutch liver patient association received the Short Form-36, the Liver Disease Symptom Index and the Multidimensional Fatigue Index-20. Based on reported clinical characteristics we classified respondents (n = 1175) as non-cirrhotic, compensated cirrhotic, decompensated cirrhotic or transplants. We used linear, ordinal and logistic regression to compare the HRQoL between groups. RESULTS: All liver patients showed a significantly worse generic HRQoL and fatigue than healthy controls. Decompensated cirrhotic patients showed a significantly worse disease-specific and generic HRQoL and fatigue than non-cirrhotic patients, while HRQoL differences between non-cirrhotic and compensated cirrhotic patients were predominantly insignificant. Transplanted patients showed a better generic HRQoL, less fatigue and lower probabilities of severe symptoms than non-cirrhotic patients, but almost equal probabilities of symptom hindrance. CONCLUSIONS: HRQoL in chronic liver patients depends on disease stage and transplant history. Non-cirrhotic and compensated cirrhotic patients have a similar HRQoL. Decompensated patients show the worst HRQoL, while transplanted patients show a significantly better HRQoL than cirrhotic and non-cirrhotic patients

Does minimally invasive lumbar disc surgery result in less muscle injury than conventional surgery? A randomized controlled trial

The concept of minimally invasive lumbar disc surgery comprises reduced muscle injury. The aim of this study was to evaluate creatine phosphokinase (CPK) in serum and the cross-sectional area (CSA) of the multifidus muscle on magnetic resonance imaging as indicators of muscle injury. We present the results of a double-blind randomized trial on patients with lumbar disc herniation, in which tubular discectomy and conventional microdiscectomy were compared. In 216 patients, CPK was measured before surgery and at day 1 after surgery. In 140 patients, the CSA of the multifidus muscle was measured at the affected disc level before surgery and at 1 year after surgery. The ratios (i.e. post surgery/pre surgery) of CPK and CSA were used as outcome measures. The multifidus atrophy was classified into three grades ranging from 0 (normal) to 3 (severe atrophy), and the difference between post and pre surgery was used as an outcome. Patients’ low-back pain scores on the visual analogue scale (VAS) were documented before surgery and at various moments during follow-up. Tubular discectomy compared with conventional microdiscectomy resulted in a nonsignificant difference in CPK ratio, although the CSA ratio was significantly lower in tubular discectomy. At 1 year, there was no difference in atrophy grade between both groups nor in the percentage of patients showing an increased atrophy grade (14% tubular vs. 18% conventional). The postoperative low-back pain scores on the VAS improved in both groups, although the 1-year between-group mean difference of improvement was 3.5 mm (95% CI; 1.4–5.7 mm) in favour of conventional microdiscectomy. In conclusion, tubular discectomy compared with conventional microdiscectomy did not result in reduced muscle injury. Postoperative evaluation of CPK and the multifidus muscle showed similar results in both groups, although patients who underwent tubular discectomy reported more low-back pain during the first year after surgery

Environmental Factors in the Relapse and Recurrence of Inflammatory Bowel Disease:A Review of the Literature

The causes of relapse in patients with Crohn's disease (CD) and ulcerative colitis (UC) are largely unknown. This paper reviews the epidemiological and clinical data on how medications (non-steroidal anti-inflammatory drugs, estrogens and antibiotics), lifestyle factors (smoking, psychological stress, diet and air pollution) may precipitate clinical relapses and recurrence. Potential biological mechanisms include: increasing thrombotic tendency, imbalances in prostaglandin synthesis, alterations in the composition of gut microbiota, and mucosal damage causing increased permeability