24 resultados para physical and chemical factors

em Consorci de Serveis Universitaris de Catalunya (CSUC), Spain


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The aim of this study was to investigate the effect of combined pressure/temperature treatments (200, 400 and 600 MPa, at 20 and 40 °C) on key physical and chemical characteristics of white cabbage (Brassica oleracea L. var. capitata alba). Thermal treatment (blanching) was also investigated and compared with high-pressure processing (HPP). HPP at 400 MPa and 20–40 °C caused significantly larger colour changes compared to any other pressure or thermal treatment. All pressure treatments induced a softening effect, whereas blanching did not significantly alter texture. Both blanching and pressure treatments resulted in a reduction in the levels of ascorbic acid, effect that was less pronounced for blanching and HPP at 600 MPa and 20–40 °C. HPP at 600 MPa resulted in significantly higher total phenol content, total antioxidant capacity and total isothiocyanate content compared to blanching. In summary, the colour and texture of white cabbage were better preserved by blanching. However, HPP at 600 MPa resulted in significantly higher levels of phytochemical compounds. The results of this study suggest that HPP may represent an attractive technology to process vegetable-based food products that better maintains important aspects related to the content of health-promoting compounds. This may be of particular relevance to the food industry sector involved in the development of convenient novel food products with excellent functional properties

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Dissolution studies have become of great significance because, in most cases, drug dissolution is the rate-limiting step in the absorption process. As occurs with solid oral dosage forms, heterogeneous disperse systems (suspensions) could also have some problems with their in vitro dissolution. The objective of this study was to evaluate influence of the excipients on the release of spironolactone from four alcohol free suspensions (pharmaceutical compounding) of spironolactone 5 mg/mL suitable for pediatric use. Also the comparison of the physical and chemical stability of the suspensions stored at 4, 25 and 40 ºC over a 60- day period has been studied. Rheological behavior, particle size, a prediction of long-term physical stability, pH and assay of spironolactone by HPLC were assessed at prefixed times. The dissolution profile of each suspension was determined and compared with that of the commercial tablets. A microbiological study of the best formula was also performed. Chemically, the four spironolactone suspensions were stable for 60 days stored at three temperatures; Suspension IV had optimum pH values and the highest recovery percentage. In terms of physical stability, sedimentation occurred in Suspension IV and flotation of spironolactone in Suspensions I, II and III. Suspension III had the highest viscosity and the slowest drug release. Suspension IV was also microbiologically stable for 60 days. In conclusion, Suspension IV had the best properties and the least suitable form was Suspension III, as its high viscosity made it difficult to achieve homogeneous redispersion, and it had the slowest dissolution profile.

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Objective: The purpose of this study was to identify the influence of readiness of change for physical activity (PA), sociodemographic factors, lifestyle and physical activity status (PAS) on perceived barriers among Spanish university students. Participants: Seven hundred and seventy two (n = 772) men and women ages 17 - 39 at a north-west regional university in Spain participated in the study. Methods: The International Physical Activity Questionnaire, the States of Change for Physical Activity Behaviour Questionnaire and the Self-perceived Barriers for Physical Activity Questionnaire were used. Description, correlation and multiple regression analyses were completed. Results: Participants self-perceived low average-score barriers (2.6 ± 1.4 over 10.0). The 3-higher scores barriers corresponded to “too much work”; “lack of time for exercise” and “laziness”. Gender, PAS and self-perceived health were shown to be associated with perceived barriers. Conclusions: University institutions should consider those factors that predict barriers to PA to develop effective intervention programs.

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Objectiu: Avaluar prevalença i factors associats a l’insomni en pacients ingressats a una unitat de cures pal•liatives. Mètode: Entrevista estructurada a pacients consecutivament ingressats avaluant l’insomni a través de l’escala Sleep Disturbance Scale, i els factors físics, psicològics i ambientals potencialment associats. Resultats principals: El 47% presentà insomni moderat a sever. Els factors potencialment associats més prevalents foren dolor, distrés psicològic, rumiacions nocturnes i factors ambientals. En l’anàlisi multivariada, rumiacions nocturnes i somnolència diürna (relació inversa) es relacionaren amb insomni moderat a sever. Conclusions: L’insomni és un símptoma prevalent relacionat amb rumiacions nocturnes i absència de somnolència diürna.

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This paper analyses the impact of a series of managerial and organisational factors on occupational injuries. These consist of occupational safety measures, as regards both the intensity and the orientation of risk prevention in companies, and the adoption of certain work organisation practices, quality management and the use of flexible production technologies. We estimate a negative binomial regression based on a sample of 213 Spanish industrial establishments, defining a constant random parameter to take account of non-observable heterogeneity. Our results show that occupational safety measures, the intensive use of quality management tools and the empowerment of workers all help to reduce the number of injuries. We have also confirmed the presence of synergies between the organisational factors analysed and the development of an occupational safety strategy featuring participation and the extension of prevention to all levels of the organisation.

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In this study, we analyse the degree of polarisation-a concept fundamentally different from that of inequality-in the international distribution of CO2 emissions per capita in the European Union. It is analytically relevant to examine the degree of instability inherent to a distribution and, in the analysed case, the likelihood that the distribution and its evolution will increase or decrease the chances of reaching an agreement. Two approaches were used to measure polarisation: the endogenous approach, in which countries are grouped according to their similarity in terms of emissions, and the exogenous approach, in which countries are grouped geographically. Our findings indicate a clear decrease in polarisation since the mid-1990s, which can essentially be explained by the fact that the different groups of countries have converged (i.e. antagonism among the CO2 emitters has decreased) as the contribution of energy intensity to between-group differences has decreased. This lower degree of polarisation in CO2 distribution suggests a situation more conducive to the possibility of reaching EU-wide agreements on the mitigation of CO2 emissions.

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The paper deals with the comparative study of European citizens' satisfaction with the state of education in their respective countries. Individual and contextual effects are tested applying multilevel analysis. The results show that educational public policies (level of decentralization, degree of comprehensiveness and public spending) as well as the students' social environment (socioeconomic and cultural status) have a sound impact on the opinions about the state of education.

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Given the current economic environment, high-growth companies are particularly relevant for their contribution to employment generation and wealth.This paper discusses the results of a survey that was conducted in order to gain a deeper understanding of high-growth cooperatives through analyzing their financial profiles and then identifying key contributing factors to their growth. To do this, we compared this particular sample with other cooperatives and other high-growth mercantile companies.The results show the main drivers related to high-growth companies success. They are the competitive advantages based on the surveyed group, modern management techniques, quality and productivity, innovation and internationalization. Additionally, we have observed some financial strengths and weaknesses. In this sense, they are under capitalized companies with an unbalanced growth.

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The paper deals with the comparative study of European citizens satisfaction with thestate of education in their respective countries. Individual and contextual effects aretested applying multilevel analysis. The results show that educational public policies(level of decentralization, degree of comprehensiveness and public spending) as well asthe students social environment (socioeconomic and cultural status) have a soundimpact on the opinions about the state of education.

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The microstructure of CuInS2-(CIS2) polycrystalline films deposited onto Mo-coated glass has been analyzed by Raman scattering, Auger electron spectroscopy (AES), transmission electron microscopy, and x-ray diffraction techniques. Samples were obtained by a coevaporation procedure that allows different Cu-to-In composition ratios (from Cu-rich to Cu-poor films). Films were grown at different temperatures between 370 and 520-°C. The combination of micro-Raman and AES techniques onto Ar+-sputtered samples has allowed us to identify the main secondary phases from Cu-poor films such as CuIn5S8 (at the central region of the layer) and MoS2 (at the CIS2/Mo interface). For Cu-rich films, secondary phases are CuS at the surface of as-grown layers and MoS2 at the CIS2/Mo interface. The lower intensity of the MoS2 modes from the Raman spectra measured at these samples suggests excess Cu to inhibit MoS2 interface formation. Decreasing the temperature of deposition to 420-°C leads to an inhibition in observing these secondary phases. This inhibition is also accompanied by a significant broadening and blueshift of the main A1 Raman mode from CIS2, as well as by an increase in the contribution of an additional mode at about 305 cm-1. The experimental data suggest that these effects are related to a decrease in structural quality of the CIS2 films obtained under low-temperature deposition conditions, which are likely connected to the inhibition in the measured spectra of secondary-phase vibrational modes.

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Sludges resulting from wastewater treatment processes have a characteristically high water content, which complicates handling operations such as pumping, transport and disposal. To enhance the dewatering of secondary sludge, the effect of ultrasound waves, thermal treatment and chemical conditioning with NaOH have been studied. Two features of treated sludges were examined: their rheological behavior and their dewaterability. The rheological tests consisted of recording shear stress when the shear rate increases and decreases continuously and linearly with time, and when it increases and decreases in steps. Steady-state viscosity and thixotropy were obtained from the rheological tests, and both decreased significantly in all cases with increased treatment intensity. Centrifugation of ultrasonicated and thermally treated sludges allowed the total solid content to be increased by approximately 16.2% and 17.6%, respectively. These dewatered sludges had a lower viscosity and thixotropy than the untreated sludge. In contrast, alkali conditioning barely allowed the sludge to be dewatered by centrifugation, despite decreasing its viscosity and thixotropy.

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The main goal of this special issue was to gather contributions dealing with the latest breakthrough methods for providing value compounds and energy/fuel from waste valorization. Valorization is a relatively new approach in the area of industrial wastes management, a key issue to promote sustainable development. In this field, the recovery of value-added substances, such as antioxidants, proteins, vitamins, and so forth, from the processing of agroindustrial byproducts, is worth mentioning. Another important valorization approach is the use of biogas from waste treatment plants for the production of energy. Several approaches involving physical and chemical processes, thermal and biological processes that ensure reduced emissions and energy consumptions were taken into account. The papers selected for this topical issue represent some of the mostly researched methods that currently promote the valorization of wastes to energy and useful materials ...

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Objectives: To evaluate the prevalence of dental agenesis and its possible association with other developmental dental anomalies and systemic entities. Setting and Sample Population: Descriptive transversal study, for which 1518 clinical records, of patients visited by the Odontological Service of the Primary Health Centre of Cassà de la Selva (Girona-Spain) between December 2002 and February 2006 were reviewed. The data were recorded in relation to the oral and dental anomalies and the associated systemic entities, between the ones referred as concomitant in literature. Results: Values of 9.48% (7.25% excluding the third molars) for dental agenesis and 0.39% for oligodontia were obtained. The presence of dental agenesis concomitant with some other forms of oral and dental anomalies was observed. Attention must be drawn to the fact that a greater number of concomitant systemic entities were observed in those patients that presented a severe phenotypical pattern of dental agenesis. Conclusions: The results of the present study do not differ from the ones reported in studies of similar characteristics among Occidental and Spanish populations. The relationship observed between certain systemic entities and developmental dental anomalies suggest a possible common genetic etiology

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Background Analysing the observed differences for incidence or mortality of a particular disease between two different situations (such as time points, geographical areas, gender or other social characteristics) can be useful both for scientific or administrative purposes. From an epidemiological and public health point of view, it is of great interest to assess the effect of demographic factors in these observed differences in order to elucidate the effect of the risk of developing a disease or dying from it. The method proposed by Bashir and Estève, which splits the observed variation into three components: risk, population structure and population size is a common choice at practice. Results A web-based application, called RiskDiff has been implemented (available at http://rht.iconcologia.net/riskdiff.htm webcite), to perform this kind of statistical analyses, providing text and graphical summaries. Code from the implemented functions in R is also provided. An application to cancer mortality data from Catalonia is used for illustration. Conclusions Combining epidemiological with demographical factors is crucial for analysing incidence or mortality from a disease, especially if the population pyramids show substantial differences. The tool implemented may serve to promote and divulgate the use of this method to give advice for epidemiologic interpretation and decision making in public health.

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Se llevó a cabo un experimento de 406 días en macetas para evaluar el nuevo inhibidor de la nitrificación, 3,4-dimetilpirazol fosfato (DMPP), añadido a purines de cerdo. Se utilizaron macetas que contenían tierra franca calcárea que fueron sujetas a los siguientes tratamientos: sin purín, 73,7; 147,3 y 221 cm3 de purín por maceta, todas con o sin tratamiento de DMPP. A los 18 días las macetas fueron sembradas con Lolium perenne L. El mayor rendimiento (36,3 g maceta-1) se obtuvo para el tratamiento con la dosis superior de purín y DMPP, siendo un 7,4% superior al mismo tratamiento sin inhibidor y un 46,1% superior al tratamiento control. Las plantas tratadas con dosis alta y mediana, más el DMPP, absorbieron el 70% del total del N durante la primera fase del experimento (104 días) mientras que sin inhibidor absorbieron el 55,3 y el 62% respectivamente. Se observó una reducción significativa del 17% en el N lixiviado en los tratamientos sin cultivo al aplicar DMPP. El inhibidor aumentó significativamente la eficiencia agronómica del purín (g materia seca g-1 N aplicado).