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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
61

Expanding the science of successful aging: Older adults living in continuing care retirement communities (CCRCs)

Petrossi, Kathryn H 25 July 2005 (has links)
Rowe and Kahns theory of successful aging identifies three main components of aging successfully: reducing the risk of disease and disability, maintaining high cognitive and physical function, and engagement with life. While there is compelling evidence that suggests the legitimacy of this concept in the 50-75 year old community dwelling population, three areas of expansion are necessary: 1.) programmatic research; 2.) extending the existing research samples to include older samples and those living in continuing care retirement communities (CCRCs); and 3.) the integration of data collection and analysis to move beyond investigation of just one successful aging outcome to include elements of all three components of successful aging. Longitudinal analysis utilizing hierarchical linear modeling (HLM) was conducted on a convenience sample of 136 older adults (mean age = 80.8 years at baseline) participating in a pilot community-wide successful aging program over a 26-month period. Results indicate the sample reported exercising frequently, ate recommended levels of fruits and vegetables, had healthy BMIs, had positive ratings of health, were highly involved in productive activities, and were satisfied with their ability to give and receive social support at baseline. High levels of mobility were measured in the sample. Participants maintained this picture of successful aging over time for the majority of outcome variables, though significant declines in self-reported health were observed. Participants also reported improvements in their satisfaction with receiving social support. Results support four major conclusions: 1.) The three criteria of successful aging identified by Rowe and Kahn (1997) were observed among older adults living in CCRCs who were enrolled in a successful aging program. 2.) Stability was observed on a number of the outcomes over 26 months in this convenience sample, which has implications for intervention/programmatic research. Despite the traditional improvement-oriented focus of programmatic research, stability or maintenance of well-being over time should be viewed as a positive outcome in older age, particularly when compared to national data depicting trends of decline. 3.) The interdependence of current results support the notion that successful aging programming needs to include multi-disciplinary intervention strategies, as supported by the finding that modifiers of physical, social, and intellectual well-being include constructs from each of the components of successful aging. 4.) Participants of the current study were largely in the precontemplation and contemplation stages of change. Readiness to change needs to be factored into the design of any successful aging program, as the Transtheoretical Model could be a powerful tool for the identification of readiness to change and the development of appropriate and effective successful aging programming.
62

Effects of Antioxidants and Pro-oxidants on Oxidative Stress and DNA Damage using the Comet Assay : Studies on Blood Cells from Type 2 Diabetes Subjects and Mouse Lymphoma Cells

Åsgård, Rikard January 2014 (has links)
Diet and oral supplements comprise two distinct sources of antioxidants known to prevent oxidative stress. Beneficial effects from antioxidants have been seen for patients at risk for type 2 diabetes. The aim of this thesis was to evaluate the positive effects of antioxidants against oxidative stress and DNA damage in type 2 diabetes subjects. We also used antioxidants as tools to determine the mechanisms behind genotoxicity induced by mutagenic pro-oxidative agents in mouse lymphoma cells. Several techniques were used to measure oxidative stress and DNA damage, but the main technique used was alkaline comet assay. The results showed that the fruit and vegetable intake was inversely related to oxidative stress in type 2 diabetes subjects. However, oral supplementary intake of 20 antioxidants did not decrease oxidative stress biomarkers. In studies on mouse lymphoma cells, using the alkaline comet assay, DNA damage was induced by catechol and o-phenylenediamine (OPD), while 4-nitro-o-phenylenediamine (4-NOPD) induced only oxidative damage, showing different mechanisms of action behind the mutagenicity of the compounds. Also, oxidative stress was induced by catechol and 4-NOPD, whereas imbalances in the nucleotide pool were seen after exposure to OPD or 4-NOPD. Addition of antioxidants together with these pro-oxidants showed that β-carotene was able to reduce DNA damage at low concentrations of catechol, but increased DNA damage at high concentration. In comparison, addition of α-tocopherol slightly decreased catechol-induced DNA damage at all concentrations of catechol. However, no effect of α-tocopherol was seen on OPD-or 4-NOPD-induced DNA damage. In conclusion, antioxidants from fruits and vegetables, but not from oral supplements, reduced oxidative stress in type 2 diabetes patients, suggesting fruits and vegetables being a healthier source for antioxidant-intake, as compared to oral supplements. Different mechanisms of action for mutagenic pro-oxidants were shown in mouse lymphoma cells, introducing the nucleotide pool as an interesting target for oxidative stress. Reduction of catechol-induced DNA damage by β-carotene or α-tocopherol was shown, with a pro-oxidative action of β-carotene at high concentration of catechol, Interestingly, α-tocopherol was not able to decrease OPD- or 4-NOPD-induced DNA damage, supporting different mechanisms of action behind the genotoxicity from the three pro-oxidants.
63

Organophosphate exposure in Australian agricultural workers : human exposure and risk assessment

Johnstone, Kelly Rose January 2006 (has links)
Organophosphate (OP) pesticides, as a group, are the most widely used insecticides in Australia. Approximately 5 000 tonnes of active ingredient are used annually (Radcliffe, 2002). The OP pesticide group consists of around 30 identifiably distinct chemicals that are synthesised and added to approximately 700 products (Radcliffe, 2002). OP pesticides are used on fruit, vegetable, grain, pasture seed, ornamental, cotton, and viticultural crops, on livestock and domestic animals, as well as for building pest control. OP pesticides all act by inhibiting the nervous system enzyme acetylcholinesterase (AChE) and as such are termed anticholinesterase insecticides. The phosphorylation of AChE and the resultant accumulation of acetylcholine are responsible for the typical symptoms of acute poisoning with OP compounds. In addition to acute health effects, OP compound exposure can result in chronic, long-term neurological effects. The traditional method of health surveillance for OP pesticide exposure is blood cholinesterase analysis, which is actually biological effect monitoring. However, there are several drawbacks associated with the use of the blood cholinesterase test, including its invasive nature, the need for baseline levels and a substantial exposure to OP pesticide before a drop in cholinesterase activity can be detected. OP pesticides are metabolised fairly rapidly by the liver to form alkyl phosphates (DAPs). Approximately 70% of OP pesticides in use in Australia will metabolise into one or more of six common DAPs. During the last 30 years, scientists have developed a urine test that detects these six degradation products. However, unlike the blood cholinesterase test, there is currently no Biological Exposure Index (BEI) for the urine DAP metabolite test. Workers in the agricultural industry - particularly those involved with mixing, loading and application tasks - are at risk of exposure to OP pesticides. It is therefore important that these workers are able to assess their risk of health effects from exposure to OP pesticides. However, currently in Queensland, workplace health and safety legislation exempts the agricultural industry from hazardous substance legislation that incorporates the requirement to perform risk assessments and health surveillance (blood cholinesterase testing) for OP pesticide exposure. The specific aim of this research was to characterise OP pesticide exposure and to assess the feasibility of using urine DAP metabolite testing as a risk assessment tool for agricultural and related industry workers exposed to OP pesticides. An additional aim among farmers was to conduct an in-depth evaluation of their knowledge, attitudes and behaviours related to handling OP pesticides and how they assess the risks associated with their use of OPs. A cross-sectional study design was used to assess exposure to OP pesticides and related issues among four groups: fruit and vegetable farmers, pilots and mixer/loaders, formulator plant staff and a control group. The study involved 51 farmers in the interviewer-administered questionnaire and 32 in urine sample provision. Eighteen pilots and mixer/loaders provided urine samples and 9 exposed formulation plant staff provided urine and blood samples. Community controls from Toowoomba Rotary clubs provided 44 urine samples and 11 non-exposed formulation plant staff provided blood and urine samples; all groups also provided responses to a self-administered questionnaire. Participant farmers were drawn from the main cropping areas in south-east Queensland - Laidley/Lowood, Gatton, and Stanthorpe. The farmer group was characterised by small owner-operators who often had primary responsibility for OP pesticide mixing and application. Farmers had good knowledge of pesticide-related safety practices; however, despite this knowledge, use of personal protective equipment (PPE) was low. More than half of the farmers did not often wear a mask/respirator (56%), gloves (54%) or overalls (65%). Material Safety Data Sheets were never or rarely read and 88.2% of farmers never or rarely read OP pesticide labels before application. There were also problems with chemical suppliers providing farmers with MSDSs. The majority of farmers (90.2%) reported that they had never had any health surveillance performed and three-quarters had never read about or been shown how to perform a formal risk assessment. The main inhibitors to the use of PPE in the farmers' group included the uncomfortable and cumbersome nature of PPE, especially in hot weather conditions, and the fear of PPE use triggering neighbours' complaints to Government authorities. Factors associated with better PPE use included having positive attitudes and beliefs toward PPE use, higher knowledge scores and low risk perception. Farmers' use of OP pesticides was infrequent, of short duration and involved application via a boom on a tractor, a lower risk application method. Consequently, urine DAP metabolite levels in this group were generally low, with 36 out of 96 samples (37.5%) containing detectable levels. Detectable results ranged from 9.00-116.00 mol/mol creatinine. Formulators exposed to OP pesticides were found to have the highest urine DAP metabolite levels (detectable levels 13.20-550.00 mol/mol creatinine), followed by pilots and mixer/loaders (detectable levels 8.40-304.00 mol/mol creatinine) and then farmers. Despite this, pilots and mixer/loaders (particularly mixer/loaders) had the greatest number of samples containing detectable levels (94.4% of samples). The DAP metabolite most frequently detected across all groups was DMTP, which was the only metabolite found in control samples. Levels found in this study are similar to those reported in international research (Takamiya, 1994, Stephens et al., 1996, Simcox et al., 1999, Mills, 2001, Cocker et al., 2002). The observed DAP levels were not associated with a drop in cholinesterase activity among the formulation plant workers, as expected from the literature. Such exposure also is unlikely to be associated with acute health effects. In contrast, there is insufficient scientific knowledge to know whether levels recorded in this study and elsewhere may be associated with long-term, chronic health effects. Notably, DMTP levels also were observed among the presumably 'unexposed' comparison groups. Environmental background level exposures to OPs producing the DAP metabolite DMTP are therefore of potential significance and may be related, at least in part, to consumption of contaminated fruit and vegetables. There is also emerging evidence to suggest that exposure to DAP metabolites themselves through diet and other sources may contribute to the concentration of DAPs, including DMTP in urine, potentially complicating assessment of occupational exposures. Nevertheless, the urine DAP metabolite test was a useful, sensitive indicator of occupational OP pesticide exposure among agricultural workers and may be of use to the industry as part of the risk assessment process. Future research should aim to establish a BEI for the urine DAP test.
64

Notificaciones por violación a requisitos sanitarios, fitosanitarios y técnicos en exportaciones hortofrutícolas latinoamericanas

Rozas González, Juan Mario 06 1900 (has links)
Las exportaciones latinoamericanas de alimentos han aumentado sostenidamente en los últimos años, así como también habrían crecido las exigencias relativas a medidas sanitarias, fitosanitarias y técnicas, sobre todo en sus principales mercados de destino: Estados Unidos y la Unión Europea. El no cumplir con estos requisitos a la producción pone en riesgo el acceso a los mercados internacionales, afectando particularmente a los países de la región por ser exportadores netos de productos alimentarios. En este contexto, la presente investigación tiene por objeto describir la situación actual de las exportaciones alimentarias latinoamericanas relativa al cumplimiento de los requisitos sanitarios, fitosanitarios y técnicos, considerando el caso particular de los productos hortofrutícolas. Para ello, se llevaron a cabo los siguientes objetivos específicos: a) describir la situación actual y evolución reciente de las exportaciones hortofrutícolas latinoamericanas hacia EEUU y la UE, b) describir el funcionamiento del Sistema de Control de Alimentos importados en ambos mercados, c) analizar las tendencias actuales de las notificaciones a productos hortofrutícolas por violación a los requerimientos ya mencionados y, d) sugerir recomendaciones acordes a la información levantada. Los resultados indican que el país con el mayor número de notificaciones por violación a los requisitos estadounidenses, es por mucho México. Sin embargo, Guatemala y Perú presentan rechazos en frontera importantes en este mercado. En conjunto, la principal violación notificada por EEUU es la presencia de pesticidas y, los productos más afectados, fueron pimientos frescos, espárragos, tubérculos, papayas, berries, uvas y bananas. Por otra parte, la UE presentó mayores notificaciones para Argentina, Brasil y República Dominicana, principalmente por presencia de aflatoxinas u otras fallas relativas a condiciones de almacenaje y transporte inadecuados, que habrían afectado principalmente envíos de leguminosas, tubérculos y frutos secos. Finalmente, se concluye que, a pesar del incremento en exigencias sanitarias, fitosanitarias y técnicas, al menos este escenario no habría provocado mayores notificaciones por violación. No obstante, de igual modo es necesario trabajar en políticas que permitan fortalecer la calidad e inocuidad de los alimentos producidos, sobre todo considerando los requisitos crecientes, pese a que, en términos generales, para la mayor parte de los países latinoamericanos sus productos hortofrutícolas no parecen ser percibidos como riesgosos. / In the past few years Latin American food exports have steadily increased as have the requirements concerning sanitary, phytosanitary and technical measures, especially in its main target markets: the United States of America and the European Union. Failure to comply with these requirements in production puts the access to international markets at risk, particularly affecting the countries of the region as they are net exporters of food products. In this context, the present study aims to describe the current situation of Latin American food exports relative to the fulfilment of sanitary, phytosanitary and technical requirements, and in particular fruit and vegetables. To this end, the following specific objectives were included in this study: a) describe the current situation and recent evolution of Latin American fruit and vegetable exports to the US and the EU, b) describe how the Food Imports Control System operates in both markets, c) analyze the current trends in notifications of horticultural products for violation of the previously mentioned requirements and, d) suggest recommendations according to the information presented in in the previous three points. The results indicate that the country with the largest number of notifications for violation of the U.S. requirements is Mexico by far. However, Guatemala and Peru both show important rejections at border in this market. Altogether, the main violation as notified by the US is the presence of pesticides, and the most affected products were fresh peppers, asparagus, tubers, papayas, berries, grapes, and bananas. On the other hand, the EU gave more notifications to Argentina, Brazil, and the Dominican Republic, mainly for the presence of aflatoxins or other failures relating to inadequate storage and transport conditions, which would have mainly affected shipments of legumes, tubers, and nuts. Finally, I conclude that despite the increase in sanitary, phytosanitary, and technical requirements, a greater number of violation notifications was not observed even though the increased regulations affect a higher percentage of fruit and vegetable shipments from leading regional exporters. However, policies that allow the strengthening of the quality and safety of foods produced must be introduced, especially considering the increased requirements, despite the fact that, generally speaking, the fruit and vegetables of most Latin American do not seem to be perceived as risky.
65

Health and Academic Achievement in College and University Students

Beane, Amber 01 May 2020 (has links)
The purpose of this non-experimental quantitative correlational study was to investigate the relationship between academic achievement and health in a national sample of college students using quantitative data analysis. Specifically, the researcher analyzed the relationship between three health-promoting behaviors (physical activity, strength training, and fruit and vegetable consumption), three negative health behaviors (cigarette, e-cigarette, and opioid use) and obesity with GPA. Cross-sectional data on student health collected from the American College Health Association’s National College Health Assessment II (ACHA-NCHA-II) and completed by 426,650 college students from 650 U.S. colleges during the semesters between 2015 and 2019 formed the foundation for this research. Nine research questions were addressed using a series of chi square tests. Results showed there was a significant positive relationship between health behaviors and grade average. Students who met the recommendations for fruit and vegetable consumption, moderate activity and vigorous physical activity were more likely to have GPAs than those who did not. Students who used cigarettes, opioids, or were obese were more likely to have GPAs.
66

High Pressure Homogenization of Selected Liquid Beverages

Yan, Bing 30 December 2016 (has links)
No description available.
67

Association entre l’accessibilité géographique aux commerces d’alimentation et le diabète type II chez les adultes québécois : analyse de la banque de données de santé CARTaGENE

Sirpal, Sanjeev 11 1900 (has links)
Contexte. La mise en place d’environnements favorables à une saine alimentation est indispensable pour assurer la santé de la population, puisque celle-ci est considérée comme étant un déterminant de la santé. De ce fait, une corrélation existe entre les habitudes alimentaires, le diabète de type II et la santé cardiovasculaire. Durant de nombreuses années, les facteurs prédisposant au diabète étaient considérés essentiellement comme des choix individuels. Un nombre croissant de recherches démontrent présentement un lien entre les facteurs environnementaux, y compris l’accessibilité géographique à des choix alimentaires sains, et le diabète. Objectif. Cette étude vise à évaluer le lien entre l’environnement alimentaire et le risque de diabète de type II pour les résidents adultes de 6 régions métropolitaines du Québec. Méthodes. Un devis quantitatif comprenant des analyses transversales est utilisé. L’unité d’analyse est l’individu. Un corpus dérivé de la banque de données CARTaGENE est exploité. Pour répondre à l’objectif, un sous-échantillon composé de 8405 adultes habitant les six grandes régions métropolitaines du Québec de la cohorte CARTAGENE est utilisé. Les participants de cet échantillon ont été interrogés sur des sujets liés à leur santé et habitudes de vie. L'exposition aux commerces d’alimentation a été opérationnalisée à partir de zones tampons de 1000 mètres autour des adresses résidentielles et par des calculs de densité et de distance en utilisant les réseaux routiers. Cinq indicateurs de densité ont été calculés : densité des épiceries et des supermarchés, densité des dépanneurs, densité des restaurants-minute, nombre des dépanneurs, et ratio de restaurants-minute et dépanneurs aux supermarchés et épiceries. Trois mesures de proximité ont été calculées : distance au plus proche supermarché ou épicerie, distance au plus proche dépanneur, et distance au plus proche restaurant-minute. Des analyses de régression logistique ont été effectuées pour évaluer les associations entre ces indicateurs et le diabète de type II autodéclaré, en tenant compte des facteurs de confusion potentiels. Résultats. Nos résultats montrent l’absence de relations statistiquement significatives entre la proximité des points de vente d’aliments, les dépanneurs les plus proches et les détaillants de restauration rapide les plus proches (premiers quartiles dans chaque catégorie), et le statut individuel de diabète de type II. En revanche, l’indice de défavorisation matérielle d’un quartier était positivement et significativement associé au risque de diabète de type II. De plus, le fait de résider dans un « désert alimentaire » était le seul indicateur de l’accès géographique qui était statistiquement et significativement associé positivement au risque de diabète de type II, à la fois dans les modèles univariés (RC = 1,42 ; IC à 95 % : 1,05, 1,90) et multivariés (RC = 1,56 ; IC à 95 % : 1,12, 2,18). Conclusion. Nos résultats n’ont montré aucune relation significative entre le statut individuel de diabète de type II et la plupart des facteurs de l’environnement alimentaire. La littérature existante a montré une association significative des indicateurs socio-économiques individuels et d’un quartier avec le risque de maladie cardiométabolique, une relation que nous avons également observée dans notre étude, en ce qui concerne le type individuel de risque de diabète de type II. En outre, le fait de résider dans un « désert alimentaire » augmentait considérablement le risque individuel de diabète de type II. Nos résultats suggèrent que les mesures de santé publique pour freiner le diabète de type II devraient simultanément aborder les facteurs de risque individuels ainsi que les aspects pertinents de l’environnement alimentaire et les indicateurs socioéconomiques du quartier. / Context. Recent studies have explored the link between the accessibility to healthy food choices and population health. Specifically, there is a demonstrated association between nutritional habits and cardiovascular/metabolic disease, especially type II diabetes. Inasmuch as a significant corpus of knowledge has focused on individual factors and diabetes risk, emerging studies demonstrate that the food environment, including geographic accessibility to whole and healthy foods, potentially has an impact on individual and population type II diabetes risk. This study draws on data from CARTaGENE, a large cross-sectional province-wide study with 43,000 participants. Objective. This study aims to evaluate the association between the food environment and type II diabetes risk among adult residents across 6 metropolitan regions of Quebec. Methods. A quantitative research design is employed, whereby cross-sectional analyses are performed. The unit of analysis is the individual. A subsample of 8405 adults living in the six major metropolitan areas of Quebec of the CARTAGENE cohort was used. Participants in this sample answered questionnaires related to their health and lifestyle habits. Exposures to food environments were operationalized using 1000-meter buffer zones around residential addresses and by distance calculations using road networks. Five density indicators were calculated: density of grocery stores and supermarkets, density of convenience stores, density of fast-food restaurants, numbers of convenience stores, and ratio of fast-food restaurants and convenience stores to supermarkets and grocery stores. Three proximity measures were calculated: distance to the nearest supermarket or grocery store, distance to the nearest convenience store and distance to the nearest fast-food restaurants. Logistic regression analyses were performed to assess associations between these indicators and self-reported type II diabetes, considering potential confounders. Results. Our results showed an absence of statistically significant relationships between proximity to food outlets, closest convenient stores, and closest fast-food restaurants (first quartiles in each category), and individual type II diabetes status. In contrast, the material deprivation index of a neighborhood was positively and significantly associated with type II diabetes risk. Furthermore, residing in a “food desert” was the only indicator of geographical access that was statistically significantly positively associated with type II diabetes risk, in both univariate (OR = 1,42 ; 95 % CI : 1,05, 1,90) and multivariate (OR = 1,56 ; 95 % CI : 1,12, 2,18) models. Conclusion. Our results showed no significant relationship between individual type II diabetes status and most food environment factors. Existent literature has shown significant association of individual and neighborhood socioeconomic indicators with cardiometabolic disease risk, a relationship we also observed in our study, insofar as individual type II diabetes risk is concerned. Furthermore, residing in a ‘food desert’ significantly increased individual type II diabetes risk. Our results suggest that public health measures to curb type II diabetes should concomitantly address individual risk factors as well pertinent aspects of the food environment, along with neighborhood socioeconomic indicators.
68

Assessing Healthy Food Access for Low-Income Households Shopping at a Farmers Market in Rural Athens County, Ohio

Bilecki, Jessica E. 11 September 2012 (has links)
No description available.
69

[en] ASSESSMENT OF PREDICTIVE MODELS FOR BIOGAS PRODUCTION USING ARTIFICIAL NEURAL NETWORKS / [pt] AVALIAÇÃO DE MODELOS PREDITIVOS PARA PRODUÇÃO DE BIOGÁS USANDO REDES NEURAIS ARTIFICIAIS

MICHEL ANGELO O W DE CARVALHO 29 April 2024 (has links)
[pt] O biogás é uma energia renovável com grande potencial de produção a partir de resíduos, incluindo resíduos alimentares. Nesse contexto, o presente trabalho apresenta o desenvolvimento de três modelos distintos usando Redes Neurais Artificiais (RNAs), com a capacidade de prever o volume acumulado de biogás, de metano e a concentração de CH4, respectivamente. Foi construído um banco de dados da literatura com variáveis do processo de biodigestão anaeróbia: tipo de biomassa, tipo de reator/alimentação, teor de sólido volátil, pH, taxa de carga orgânica, tempo de retenção hidráulica, temperatura e volume do reator. Para cada conjunto de modelos, foram desenvolvidas e testadas 24 RNAs utilizando a ferramenta computacional MATLAB. As RNAs foram avaliadas pela sua capacidade de estimação através do coeficiente de determinação (R2 ) e também através da soma do erro quadrático (SSE) obtidos. Após as etapas iniciais, as redes neurais foram usadas para criar superfícies de resposta, buscando regiões ideais para produção de biogás e metano. Contudo, um único modelo não atingiu a representatividade desejada, levando à segmentação dos dados por tipo de biomassa. As RNAs desenvolvidas demonstraram eficácia na estimação dos grupos usados para treinamento, teste e validação. A melhor rede alcançou R2 de 0,9969 para biogás, 0,9963 para metano e 0,9386 para a porcentagem de metano, com SSE de 0,1808, 0,1089 e 11,45, respectivamente. A estratégia de combinar variáveis do processo em superfícies de resposta revelou-se útil para identificar pontos ótimos no processo produtivo. / [en] Biogas is a renewable energy source with significant production potential from various waste materials, including food waste. In this context, this study presents the development of three distinct models using Artificial Neural Networks (ANNs), capable of predicting the cumulative volume of biogas, methane, and CH4 concentration, respectively. A literature-based database was constructed, including variables from anaerobic digestion processes: biomass type, reactor/feed type, volatile solid content, pH, organic loading rate, hydraulic retention time, temperature, and reactor volume. For each set of models, 24 ANNs were developed and tested using the MATLAB computational tool. The ANNs estimation capability was assessed using the coefficient of determination (R2) and the sum of squared errors (SSE). Following initial stages, neural networks were employed to create response surfaces, aiming to identify optimal regions for biogas and methane production. However, a single model failed to achieve the desired representativeness, leading to data segmentation based on biomass type. The developed ANNs demonstrated effectiveness in estimating the groups used for training, testing, and validation. The best network achieved R2 values of 0.9969 for biogas, 0.9963 for methane, and 0.9386 for methane percentage, with SSE values of 0.1808, 0.1089, and 11.45, respectively. The strategy of combining process variables in response surfaces proved valuable in identifying optimal points in the production process.
70

Određivanje sadržaja patulina u proizvodima od jabuka i procena izloženosti stanovništva patulinu / Determination of patulin in apple products and population exposure assessment

Dimitrov Nina 13 July 2018 (has links)
<p>Sprovedena studija po prvi put izve&scaron;tava o prisustvu patulina, sekundarnog metabolita određenih vrsta plesni, u proizvodima od jabuka, kao i proceni rizika usled unosa patulina od strane odojčadi, dece, adolescenata i odrasle populacije u Republici Srbiji. Ukupno 356 uzoraka sokova i ka&scaron;ica za odojčad i malu decu (48 i 66, redom), sokova za decu (mala pakovanja sa cevčicom, 100) i sokova u porodičnom pakovanju (142), sakupljeno je sa trži&scaron;ta tokom tri godine i analizirano primenom tečne hromatografije sa ultraljubičastom detekcijom, metodom koja je predhodno validirana. Prisustvo patulina je detektovano u 44% i 17% uzoraka sokova i ka&scaron;ica za odojčad i malu decu, redom, u količinama nižim od zakonskog ograničenja od 10 &mu;g/kg (maksimalno 8,3 i 7,7 &mu;g/kg, redom). Udeo kontaminiranih uzoraka među sokovima za decu iznosio je 43%, sa najvi&scaron;om koncentracijom patulina od 30,2 &mu;g/kg ispod maksimalno dozvoljenog nivoa od 50 &mu;g/kg. Patulin je detektovan u 51% sokova u porodičnom pakovanju, sa 0,7% uzoraka iznad zakonske granice od 50 &mu;g/kg (prosečna koncentracija 4,3 &mu;g/kg). Sokovi od jabuka su pokazali značajno vi&scaron;i udeo kontaminiranih uzoraka (74% u odnosu na 28%), kao i vi&scaron;i prosečni sadržaj patulina (6,4 u odnosu na 2,1 &mu;g/kg) u poređenju sa sokovima od me&scaron;anog voća. Procena rizika usled unosa patulina od strane odojčadi, dece, adolescenata i odrasle populacije u Republici Srbiji, sprovedena primenom determinističkog i probabilističkog pristupa, uključujući rezultate biodostupnosti patulina, pokazala je da je odnos između procenjenog dnevnog unosa i toksikolo&scaron;ke referentne doze za patulin od 0,4 &mu;g/kg telesne mase, koji se označava kao &ldquo;hazard quotient&rdquo;, znatno ispod 1, &scaron;to ukazuje na tolerantan nivo izloženosti i nepostojanje razloga za zabrinutost za zdravlje populacije. Dodatno, analiza ostataka pesticida i toksičnih metala potvrdila je bezbednost proizvoda od jabuka na trži&scaron;tu. Međutim, identifikacija vi&scaron;estrukih ostataka pesticida je razlog za aktivan pristup i pažljivo planiranje i sprovođenje monitoringa bezbednosti hrane, posebno hrane za odojčad i malu decu, kao najosetljivije populacione grupe.</p> / <p>This study reports for the first time the occurrence of patulin, a secondary metabolite of certain fungi, in apple-based food, as well as risk assessment related to patulin intake by infants, children, adolescents and adults in Serbia. In total, 356 samples of infant fruit juices (48), infant pur&eacute;e (66), juices for children (small package with straw, 100), and juices in family package (142) were collected from the market over three years (2013&ndash;15) and analysed using validated method based on liquid chromatography with ultraviolet detection. Patulin was found in 44% of infant juices and 17% of infant pur&eacute;e, with all values below the legal limit of 10 &mu;g/kg (maximum 8.3 and 7.7 &mu;g/kg, respectively). The proportion of contaminated samples among fruit juices for children was 43%, with the highest patulin concentration at 30.2 &mu;g/kg, not exceeding the maximum allowed level of 50 &mu;g/kg. Patulin was found in 51% of juices in family package, with 0.7% of the samples in excess of the legal limit of 50 &mu;g/kg (mean 4.3 &mu;g/kg). Apple juices showed significantly higher percentage of contaminated samples (74% versus 28%), as well as higher mean patulin content (6.4 versus 2.1 &mu;g/kg) when compared with the multifruit ones. Risk assessment of patulin intake by Serbian infants, children, adolescents and adults, conducted by deterministic and probabilistic approaches and including the bioaccessibility results, revealed a ratio between exposure and toxicological reference dose for patulin of 0,4 &mu;g/kg body weigth, called hazard quotients, well below 1, indicating a tolerable exposure level and no health concern. Furthermore, analysis of pesticide residues and toxic metals confirmed safety of apple products on the market. However, identification of multiple pesticide residues is a reason for an active attitude and carefully planned and conducted monitoring of food safety, expecialy in the case of food for infants and young children, as they are the most susceptible population group.</p>

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