abstract: Other studies have previously demonstrated that perceived stress and maladaptive stress management can lead to harmful outcomes including depression, morbidity, and mortality. College students (especially freshmen) have more difficulty dealing with stress, which can increase their susceptibility to engage in high risk behaviors. The importance of conducting this research is to discover the effects that perceived stress levels may have on depression outcomes in college students, and to evaluate the influence of health related behaviors on this relationship. This study used a retrospective cross-sectional correlational design to examine correlations between perceived stress, physical activity, and other health behaviors on clinical and perceived depression in college students. A random sample of 20,000 students was drawn from 62,476 students enrolled at Arizona State University (ASU). Participants included 2,238 students who volunteered to take the American College Health Association-National College Health Assessment (ACHA-NCHA) in spring 2009. Supplemental questions for ASU students were developed by ASU Wellness and administered as a part of the ACHA-NCHA II. The university sent an invitation email, wherein students were directed through a hyperlink to the survey website. ACHA provided institutional survey data in an SPSS file for analysis. The data were evaluated with Spearman Rho Correlation Analysis and Wilcoxon-Mann-Whitney test. There were more female participants (n = 580) than males (n = 483), both averaged 23 years of age. Men had greater height, weight, and body mass index than females, all were significant mean differences. There were more significant correlations between health factors and having perceived depression than with having real or diagnosed depression. Logistic regression showed that out of all variables and behaviors studied, only high levels of stress, poor general health, substance use, and gender (female) resulted in significant odds in predicting that a participant would be in one of the depression categories. This research suggests that addressing these factors may be important to prevent and reduce depression among college students. This study provides empirical evidence that there is a significant relationship between perceived stress and depression among college students, and that health behaviors such as substance abuse have a negative mediating effect on this relationship. / Dissertation/Thesis / M.S. Exercise and Wellness 2011

Made available in DSpace on 2014-12-17T14:03:41Z (GMT). No. of bitstreams: 1 TarcianaCGA.pdf: 634423 bytes, checksum: 54bd90fdc2abea42aaa8c6e698915963 (MD5) Previous issue date: 2006-07-18 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Fucans are a family of sulfated homo and teropolysaccharides respectively, composed mainly of a- (1?2) and a- (1?3) linked by L-fucose residues. Properties such as the ability to act as an anti-contraceptive, to reduce cholesterol levels, and to act as an anti-tumor agent are much related. We have focused our attention on the anticoagulant properties, platelet aggregation, hemorrhagic activity and complement system in vitro of commercial fucoidan (F) and their purified fractions (F1, F2 and F3) from Fucus vesiculosus obtained from fractionation of the fucoidan with different concentrations of acetone 1, 2 and 3v. These compounds were chemically characterized and the fucoidan (F) was modified by desulfation. The anticoagulant activity of the compounds was assessment by activated partial thromboplastin time (APTT) and prothrombine time assay (PT) using citrated normal human plasma. The results of APPT test showed that F, F1 and F2 have high anticoagulants activities 240.0 s (5 ?g). The F3 showed 73.7 s in the same concentrations. The results obtained with PT test to F, F1, F2 and F3 were 81.5 s, 120.0 s, 57.1 and 32.5 s respectively with 50 ?g. The dessulfated polymer showed a decrease in the anticoagulant activity in these two tests. Platelet aggregation assay was measured turbidimetrically with platelet aggregometer by method of Born. The aggregation platelet with F and fractions F1, F2 and F3 exhibited a two-phase answer in the concentration of 5 mg/mL with maximum aggregation of 76.36 ? 10.3% ; 69.54 ? 9.40%; 75.94 ? 9.01%; 51.13 ? 9.59% respectively. However, was observed a hipoaggregate profile F (15.17 ? 5.2%), F1 (7.40 ? 3.04 %), F2 (19.1 ? 5.41%) and F3 (5.09 ? 3.02%) at 0.1 mg/mL. The hemorrhagic activity assay was carried in Wistar rats and showed that these compounds have low hemorrhagic effect when compared to heparin. The complement system ( alternative pathway was made using non-sensibilized rabbit red blood cells The results of complement system essay showed that F , F2 and F3 have action inhibitory in relation to the group control 0.544, 0.697, 0.622 and 0.958 respectively The results showed that these compounds have action on this system. Interaction of the polisaccharides with proteins C3 and C4 showed that the fraction F1 stimulated the activity assay hemolytic using red blood cells / Fucanas s?o uma fam?lia de homo e hetero polissacar?deos sulfatados, formadas por uma cadeia central com liga??es α-(1→2) ou α-(1→3) unidas atrav?s de res?duos de L-fucose. Propriedades como a habilidade para agir como um anticoncepcional, reduzir n?veis de colesterol, e agir como um agente anti-tumoral foram relatadas. N?s focalizamos nossa aten??o nas propriedades anticoagulantes, agrega??o plaquet?ria, atividade anti-hemost?tica e sistema de complemento in vitro do fucoidan comercial e das fra??es F1, F2 e F3 de Fucus vesiculosus obtidas atrav?s do fracionamento do fucoidan por precipta??o com acetona (1, 2 e 3v). A atividade anticoagulante dos compostos foi avaliada pelo tempo de tromboplastina parcial ativado (APTT) e o tempo de protrombina (PT) usando plasma humano citratado. Os resultados do teste de APPT mostraram que o Fucoidan (F) e as fra??es F1 e F2 t?m altas atividades anticoagulantes 240,0 s (5 ?g), enquanto que a F3 mostrou 73,7s nas mesma concentra??o. Os resultados obtidos com PT para o F, F1, F2 e F3 foram 81,5 s, 120,0 s, 57,1 e 32,5 s respectivamente usando a massa de 50 ?g. A dessulfata??o do Fucoidan demonstrou uma diminui??o da atividade anticoagulante nos dois testes. O ensaio de agrega??o plaquet?ria foi realizado no agregometro de acordo com o m?todo de Born. A agrega??o plaquet?ria induzida pelo fucoidam e pelas fra??es de F1, F2 e F3 exibiram uma resposta bif?sica na concentra??o de 5 mg/mL com amplitude m?xima de agrega??o de 76,36% ? 10,3%; 69,54% ? 9,40%; 75,94% ? 9,01%; 51,13% ? 9,59% respectivamente. Por?m, na concentra??o 0,1 mg/mL foi observada um perfil hipoagregante para o Fucoidan (15,17% ? 5,2) e para as fra??es F1 (7,4% ? 3,04%), F2 (19,1% ? 5,41) e F3 (5,09% ? 3,02%). A atividade anti-hemost?tica foi realizada com ratos machos da linhagem Wistar e demonstrou que estes compostos t?m efeito hemorr?gico residual menor do que o da heparina. A a??o dos polissacar?deos fucosilados sulfatados na via alternativa do sistema complemento foi realizada atrav?s da utiliza??o de eritr?citos de coelhos n?o sensibilizados. Os resultados para o Sistema Complemento mostraram que o F, F2 e F3 t?m a??o neste sistema, apresentando efeito inibit?rio em rela??o ao grupo controle 0,544, 0,697, 0,622 e 0,958 respectivamente. Intera??es dos polissacar?deos com as prote?nas C3 e C4 demonstraram que a fra??o F1 estimula a atividade hemol?tica do complemento usando eritr?citos de coelho. Conclu?mos que estes a??cares t?m atividade anticoagulante e atuam como inibidores do sistema complemento sendo uma valiosa droga que pode ser empregada em doen?as relacionadas com inflama??o e coagula??o sang??nea