Diffusive model to assess the release of chemicals from a material under intermittent release conditions.

We consider the archetype situation of a chemical species that diffuses in a material and irreversibly escapes through the interface. In our setup, the interface switches between two states corresponding to 'release phase' (absorbing boundary) during which the species is released to the exterior, and 'pause phase' (reflecting boundary) during which the species is not released and its concentration profile inside the material partially relaxes back to uniformity. By combining numerical solution of the diffusion equation and statistical analysis of the outcomes, we derive upper and lower bounds and an empirical approximation for the amount of species released up to a certain time, in which the only information about the release-pause alternation schedule is the number of release phases and the average duration of a release phase. The methodology is developed thinking especially to dermal exposure assessment in the case of a slab-like homogeneous material irreversibly releasing chemicals during a number of contacts. However, upon proper extensions, this approach might be useful for inspecting other situations that are encountered, for instance, when dealing with leakage of chemicals in environmental contexts and regulatory toxicology.

Life cycle energy and environmental impacts of a solid oxide fuel cell micro-CHP system for residential application.

Fuel cells are considered one of the key technologies to reach the ambitious European goal of a low carbon economy, by reducing CO2 emissions and limiting the production of other pollutants. The manuscript presents an assessment of the life cycle energy and environmental performances of a solid oxide fuel cell system for household applications using primary data from the manufacturing phase and experimental data for the start-up and operation phases. The Life Cycle Assessment methodology is applied, based on a functional unit of 1 MJ of exergy and includes the life cycle steps from the raw materials extraction to the maintenance. The results show a particular relevance of the operation stage on the impacts (about 98% of cumulative energy demand and more than 63% of about half of the examined environmental impacts), mainly due to the fuel supply and, focusing on climate change, to the CO2 emissions during the conversion of chemical energy into electricity. Manufacturing step is the main responsible of the remaining half of the impacts, with a contribution higher than 38%, mainly imputable to the stacks production. For almost half of the examined impact, a contribution of 20-30% is caused by the maintenance step, with a relevant contribution of the stacks and DC/DC booster substitutions. The analysis highlights that eco-design solutions of the assessed system can be traced in the improvement of the energy system efficiency and reduction of emissions during the operation, and in the increase of the durability of the system components, thus reducing the number of their substitutions. The results of a sensitivity analysis on the selection of the functional unit also clarified the importance of the recovery of the thermal energy generated by the fuel cells, in order to avoid concurrent energy generation from conventional sources.

Hump height in idiopathic scoliosis measured using a humpmeter in growing subjects: relationship between the hump height and the Cobb angle and the effect of age on the hump height.

BACKGROUND: The comparison between Cobb angle and hump height measured using a humpmeter in idiopathic scoliosis have produced contradictory findings concerning the association between the two variables in growing subjects. AIM: To analyze the relationship between the hump height and the Cobb angle and the effect of age on the first. DESIGN: Cross-sectional, descriptive analytical study. SETTING: A tertiary university hospital. POPULATION: One thousand two-hundred forty-five subjects with diagnosed idiopathic scoliosis or with a hump without spine deformity, aged between 3-21. METHODS: The hump was measured with subjects in a forward-bending position using a pocket humpmeter; the Cobb angle was determined on a traditional radiograph. A linear regression estimated the Cobb angle in relation to the hump height, and a multiple regression based on standardized regression coefficients (ß) and coefficients of determination (R2) assessed the contribution of age and the Cobb angle to hump variations. RESULTS: The hump height was between 0-50 mm and the Cobb angle was between 0-78°. Based on regression coefficients, every unit (1 mm) increase in the thoracic/thoracolumbar and lumbar humps corresponded to an average increase in the Cobb angle of 1.542° (SE 0.037°; P=0.000) and 1.857° (SE 0.095°; P=0.000), respectively. The 95% confidence intervals for the estimated mean Cobb angles and those for the individual angles with respect to a given hump height lead to various hypotheses regarding the interconnection between the two entities. ß values for age were low with respect to ß values for the Cobb angle both at the thoracic level (0.095 vs. 0.807) and at the lumbar one (0.138 vs. 0.651), and R2, after the age-variable was excluded, decreased slightly from 70.3% to 69.4% and from 48.5% to 46.7%, respectively. CONCLUSIONS: Humpmeter measurements can thus be considered reliable in diagnosed idiopathic scoliosis and in asymmetric children - having a hump without deformity in spine - regardless of age. CLINICAL REHABILITATION IMPACT: Hump severity can be considered the balance needle when children with idiopathic scoliosis and asymmetric children are being treated and/or monitored. The humpmeter technique, coupled with Cobb angle measurement, can facilitate the clinical evaluation.

Clinical and Pulmonary Function Markers of Respiratory Exacerbation Risk in Subjects With Quadriplegic Cerebral Palsy.

BACKGROUND: Although respiratory exacerbations are common in patients with quadriplegic cerebral palsy (CP), little is known about the factors that are related to increased exacerbation risk. This study aimed to identify the clinical and pulmonary function variables signaling risk of exacerbation in this type of patient. METHODS: Thirty-one children and young adults with quadriplegic CP underwent a comprehensive history, physical examination, and pulmonary function test, including arterial blood gas analysis, airway resistance using the interrupter technique, and home overnight SpO2 monitoring. Subjects were divided into 2 groups depending on the number of respiratory exacerbations reported during the year before study entry: frequent exacerbators (ie, ≥ 2 exacerbations) and infrequent exacerbators (ie, < 2 exacerbations). RESULTS: The frequent exacerbators were more likely to require hospitalization due to respiratory disorders compared with the infrequent exacerbators (13/14 vs 9/17, P = .02). Respiratory exacerbation was found to be associated with diagnosis of gastroesophageal reflux (adjusted odds ratio of 23.95 for subjects with confirmed diagnosis, P = .02) and higher PaCO2 levels (adjusted odds ratio of 12.60 for every 5-mm Hg increase in PaCO2 , P = .05). Subjects with PaCO2 ≥ 35 mm Hg showed an exacerbation odds ratio of 15.2 (95% CI 1.5-152.5, P = .01). CONCLUSIONS: Gastroesophageal reflux and increased PaCO2 can be considered simple, clinically useful markers of increased exacerbation risk in young subjects with quadriplegic CP.

Goniometer evaluation of thoracic kyphosis and lumbar lordosis in subjects during growth age: a validity study.

INTRODUCTION: The aim of the present study is to evaluate the validity of a pocket compass needle goniometer (IncliMed®, University of Padua) to measure the thoracic kyphosis and lumbar lordosis in children and adolescent. MATERIAL AND METHODS: In a group of 128 adolescent the same clinician (FC) measured the thoracic kyphosis and lumbar lordosis according to the goniometer technique and the Cobb angle on lateral spinal radiographs. The linear regression analysis and the Bland and Altman criteria were used for the data analysis. RESULTS: A strong concordance existed between radiological and goniometer evaluation of the thoracic kyphosis (linear regression coefficient: b=0.897;p=0.000), but poor concordance existed at the lumbar lordosis evaluation (b=0.526;p=0.000); so we introduced a modification of the original traditional Cobb method of measurement with improved the linear regression coefficient (b=0.820,p=0.000). CONCLUSIONS: Our results confirm the clinical utility of goniometer assessment for the quantification of thoracic kyphosis and lumbar lordosis in children and adolescent.

Reading compounds in neglect dyslexia: the headedness effect.

Reading compound words was studied in neglect dyslexia in order to assess the influence of 'headedness'. The 'head' of a compound is the component that determines the grammatical category, the syntactic (e.g., the gender) and the semantic properties of the compound as a whole. For example, in the word 'blackberry'berry is the compound's head. The question was addressed of whether or not the privileged status of the head constituent influences processing and determines behavioural patterns in the breakdown of spatial attention in neglect. Italian right-headed (e.g. capobanda, band leader) and left-headed compounds (e.g. astronave, spaceship) were administered to 18 participants affected by neglect dyslexia. Left-headed compounds were read better than right-headed compounds. This result was not due to factors such as frequency, familiarity, age of acquisition or imageability, since these effects were controlled. It is suggested that attention is captured by the head component after implicit reading of the whole word. The head would require a relatively lighter processing load than the modifier and benefit from top-down facilitation.

Theory of Mind in patients with ventromedial or dorsolateral prefrontal lesions following traumatic brain injury.

PRIMARY OBJECTIVE: Previous studies on patients with traumatic brain injuries (TBI) and diffuse brain damages have reported selective deficits in mental states reasoning or 'Theory of Mind' (ToM). The goal of the current study is to investigate the fundamental role of the prefrontal cortex in two ToM components: inferential reasoning and social perception. RESEARCH DESIGN: Selective cognitive impairments following a TBI provide crucial evidence for assessing competing models of specific aspects of the cognitive system. METHOD AND PROCEDURE: This study compared the performance of patients with predominantly focal lesions in the ventromedial (n = 11) or dorsolateral prefrontal cortex (n = 7) with matched controls (n = 20). All subjects performed two ToM tasks: the Eyes Test and the Faux-pas Test. RESULTS: It was found that both groups of patients performed equally poorly on the Eyes Test, but only patients with predominantly lesions in the ventromedial cortex performed poorly on the Faux-pas test. The group effects on ToM tasks could not be reduced to differences in the global severity of brain injuries. CONCLUSIONS: These results provide evidence supporting some current models of the fractionation of the mind-reading system and support the claim that the ventromedial cortex plays a fundamental role in inferential reasoning.