Snow metamorphism: a fractal approach

Snow is a porous disordered medium consisting of air and three water phases: ice, vapour and liquid. The ice phase consists of an assemblage of grains, ice matrix, initially arranged over a random load bearing skeleton. The quantitative relationship between density and morphological characteristics of different snow microstructures is still an open issue. In this work, a three-dimensional fractal description of density corresponding to different snow microstructure is put forward. First, snow density is simulated in terms of a generalized Menger sponge model. Then, a fully three-dimensional compact stochastic fractal model is adopted. The latter approach yields a quantitative map of the randomness of the snow texture, which is described as a three-dimensional fractional Brownian field with the Hurst exponent H varying as continuous parameter. The Hurst exponent is found to be strongly dependent on snow morphology and density. The approach might be applied to all those cases where the morphological evolution of snow cover or ice sheets should be conveniently described at a quantitative level

The opinion of clinical staff regarding painfulness of procedures in pediatric hematology-oncology: an Italian survey

<p>Abstract</p> <p>Background</p> <p>Beliefs of caregivers about patient's pain have been shown to influence assessment and treatment of children's pain, now considered an essential part of cancer treatment. Painful procedures in hematology-oncology are frequently referred by children as the most painful experiences during illness. Aim of this study was to evaluate professionals' beliefs about painfulness of invasive procedures repeatedly performed in Pediatric Hemato-Oncology Units.</p> <p>Methods</p> <p>Physicians, nurses, psychologists and directors working in Hemato-Oncology Units of the Italian Association of Pediatric Hematology-Oncology (AIEOP) were involved in a wide-nation survey. The survey was based on an anonymous questionnaire investigating beliefs of operators about painfulness of invasive procedures (lumbar puncture, bone marrow aspirate and bone marrow biopsy) and level of pain management.</p> <p>Results</p> <p>Twenty-four directors, 120 physicians, 248 nurses and 22 psychologists responded to the questionnaire. The score assigned to the procedural pain on a 0-10 scale was higher than 5 in 77% of the operators for lumbar puncture, 97.5% for bone marrow aspiration, and 99.5% for bone marrow biopsy. The scores assigned by nurses differed statistically from those of the physicians and directors for the pain caused by lumbar puncture and bone marrow aspiration. Measures adopted for procedural pain control were generally considered good.</p> <p>Conclusions</p> <p>Invasive diagnostic-therapeutic procedures performed in Italian Pediatric Hemato-Oncology Units are considered painful by all the caregivers involved. Pain management is generally considered good. Aprioristically opinions about pain depend on invasiveness of the procedure and on the professional role.</p

Surgery for Anomalous Aortic Origin of a Coronary Artery (AAOCA) in Children and Adolescents: A Meta-Analysis

We conducted a systematic review and meta-analysis of the literature to assess the outcomes of surgery for the anomalous aortic origin of a coronary artery in children and young adults (&lt;30 years). Thirteen publications were selected, including a total of 384 patients. Unroofing of the intramural segment was adopted in 92% (95% CI: 81 %-98%) of cases, with pooled early and late mortality of 0% (95% CI: 0%-0.3%) and 0.1% (95% CI: 0%-1%), respectively. Reoperation for aortic regurgitation was anecdotal. Surgical management of anomalous aortic origin of coronary arteries can be achieved with excellent results in pediatric patients, but concerns remain about the durability of surgery

Multiscale modelling of snow microstructure

A three-dimensional multiscale spatial model of snow with evolving microstructure is presented. Many engineering and environmental problems require a comprehensive understanding of snow behavior which arises as a consequence of phenomena spanning a wide spectrum of spatial length scales. Snow is classically described as a granular heterogeneous medium consisting of air and three water phases: ice, vapor, and liquid. The ice phase consists of grains arranged on a matrix according to a random load-bearing skeleton. The challenge is to achieve a detailed description of the mechanical and morphological characteristics of different snow microstructures that may have the same global density. Snow density can be determined by in situ measurements with quite good accuracy, and by means of the box-counting method, the fractal dimension of snow samples characterized by grains with different diameters could be determined. It was suggested that the fractal dimension can be adopted as a relevant parameter for quantifying snow morphology, in terms of the distribution of voids, and density over a wide range of spatial scales. In this work this concept is further developed. Snow density is simulated by means of a lacunar fractal, namely, a generalized Menger sponge. Then, a fully three- dimensional invasive stochastic fractal model is adopted. This model performs a three-dimensional mapping of the snow density to a three-dimensional fractional Brownian field. In particular, snow samples with evolving microstructure are quantified as a continuous function of the fractal dimensio

Temperatures generated during implant site preparation with conventional drilling versus single-drill method: an ex-vivo human mandible study

BAC KGRO UND: Bone overheating during osteotomy is a potential cause of necrosis and consequent failure of dental implant osseointegration. The aim of this study is to identify any differences between conventional osteotomy with drills of increasing size and the use of a single drill in terms of the temperature increase in the bone during implant site preparation. MET HODS: Thirty-eight implant sites were prepared in ex vivo human mandibles, 19 using the conventional method with drills of increasing diameter (group A) and 19 using a single-drill method (group B), with no irrigation in either procedure. An infrared thermometer was used to measure the temperature difference (T\ub0) induced by the drills at each site. Student\u2019s t-test (with P<0.05) was used to compare the temperature increase induced by the last drill in group A, and by the single drill in group B. RESULTS: The mean \u394T\ub0 in group A was 0.64 \ub0C, while in group B it was 1.47 \ub0C. The difference between the temperatures obtained in the two groups was statistically significant (P=0.0073). CONCLUSIONS: In statistical terms, the two methods differ significantly in the temperature increase induced by the drilling procedure, but this difference is clinically irrelevant

Impact of oral immunotherapy on quality of life in children with cow milk allergy: a pilot study.

Quality of life is negatively affected in children with food allergy. Oral immunotherapy is an approach to food allergy that leads to patient desensitization by administering gradually increasing amounts of a given food allergen. The aim of this pilot study is to evaluate how oral immunotherapy affects quality of life in children allergic to cow milk proteins. Thirty children (aged 3-12 years) with cow milk allergy were recruited. Their parents were provided with a validated disease specific quality of life questionnaire (the food allergy quality of life questionnaire \u96 parent form, FAQLQ-PF) before and again 2 months after completing an oral immunotherapy protocol with cow milk. A significant improvement in all the investigated domains - emotional impact, food anxiety and social and dietary limitations - was found. The separate analysis of the different age groups demonstrated that the emotional impact and the food-related anxiety improved in children older than 4, while the social domains improved in each age group. In this pilot experience, oral immunotherapy significantly improves quality of life in children with cow milk allergy. The improvement seems particularly evident in children over 4 years old, who are most likely to benefit from the oral immunotherapy approach. Further placebo-controlled studies are needed to confirm these preliminary results

Myofascial points treatment with focused extracorporeal shock waves (f-ESW) for plantar fasciitis: an open label randomized clinical trial

Background: Plantar fasciitis (PF) is a common cause of heel pain. Among the several conservative treatment options, Extracorporeal Shock Wave Therapy (ESWT) is considered the standard treatment. However, recent studies suggest that PF may be sustained by a myofascial impairment proximal to the pain area with a biomechanical disequilibrium of the entire limb and pelvis. Aim of the study: By combining the concepts of Fascial Manipulation and ESWT, the purpose of this study was to evaluate the effectiveness of the ESWT on myofascial points in a sample of subjects with PF. Study design: open label randomized controlled clinical trial. Setting: outpatient clinic. Methods and population: Patients with PF were randomly assigned to an Experimental treatment Group (EG), treated with focused ESWT on myofascial points, and a Control Group (CG), treated with the focused ESWT traditional approach on the medial calcaneal tubercle. Every patient underwent a 3-session program and follow-up after 1 and 4 months. Outcome measures included the Foot and Ankle Outcome Score (FAOS) and the Italian Foot Functional Index (17-iFFI). Results: Thirty patients were enrolled in the study. Four patients of the CG dropped out the study, therefore twenty-six patients were included in the final analysis. Improvement in 17-iFFI and FAOS scores was observed in both groups starting from the third treatment and confirmed at the 1-month and 4- month follow-ups, with earlier improvement in the score values observed in the EG. Conclusions: ESWT on myofascial points could provide an interesting alternative with better outcomes in terms of time needed for recovery compared to traditional ESWT for the conservative management of PF

Intentional coverage of the left subclavian artery during endovascular repair of traumatic descending thoracic aortic transection.

OBJECTIVE: This single-center, prospective study aimed to investigate the technical success and outcome of intentional coverage of the left subclavian artery (LSA) in patients undergoing thoracic endovascular aortic repair (TEVAR) for traumatic rupture of the aortic isthmus at a tertiary care medical center. METHODS: From January 2005 to June 2011, patients who presented with traumatic aortic transection underwent TEVAR with coverage of the LSA when the distance between the artery and the rupture was 60% with respect to the contralateral one was considered relevant. Functional status of the left arm was evaluated using a provocative test. Thoracoabdominal computerized tomographic angiography was performed postoperatively at 3-, 6-, and 12-month follow-up. RESULTS: Thirty-one patients (mean age 35 years) underwent emergency TEVAR for traumatic aortic transection with intentional LSA coverage during the study period. In four cases (12.9%) coverage was partial. Two patients (6.4%) died during the postoperative period due to associated lesions. No signs of vertebrobasilar insufficiency, stroke, or paraplegia were observed in any of the patients. Nine patients (36%) had severe arm claudication (ischemic pain within 60 seconds of beginning arm exercise and decrease of PSV between 50% and 60%). Risk factors for the condition were left vertebral artery diameter <3 mm (P < .0001). A significant correlation was found between the degree of PSV reduction and left arm symptoms (P < .0001). There was an improvement in ischemic arm symptoms (P < .0001) during mean follow-up of 36 months (range, 6-65 months), with only one patient (4.2%) presenting with severe claudication. Freedom from reintervention at 48 months was 93.5%. No signs of endoleaks or graft migrations were detected on computerized tomographic angiography control scans. CONCLUSIONS: Coverage of the LSA during TEVAR for traumatic aortic injuries appears to be a feasible, safe method for extending the endograft landing zone without increasing the risk of paraplegia, stroke, or left arm ischemia. Left vertebral artery diameter can be used to identify patients at risk for postoperative left arm ischemia