Browsing by Issue Date, starting with "2023-02-17"
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- Optimization of chitosan-hydroxyapatite-based bioinks for potential 3d bioprinting application in bone tissue regenerationPublication . Costa, Ana Helena Alves da; Piccirillo, Clara; Scalera, FrancescaWith the passing of the years, scientific evolution has contributed many times to medicine by providing solutions to, what seemed to be, life-long problems for patients. Not all health problems can be fixed with traditional treatments, as not all complications are caused by drug treated diseases. This is especially true with bone related issues. Age, accidents or birth defects can all be at fault for serious skeletal defects that cannot be treated on their own. This necessity to create further solutions to aid in medicine, arose an interest in the scientific community. Fast forward to this day and age, we can now count on a vast number of options to help in bone repair and regeneration, particularly 3D bioprinted scaffolds. In this study, the main goal was to create and optimize a biomaterial that could be used as an ink to create 3D bioprinted structures for future bone regeneration application. The material used consisted of a chitosan (Ch) -based hydrogel with the incorporation of hydroxyapatite (HA), which is known as the most common calcium phosphate present in human bone. Synthetic HA (SYN_HA) was synthesized and showed to be a suitable material for hydrogel preparation; natural HA (NAT_HA) from tuna fish bones, however, also looked as a very interesting alternative, although it still requires some additional work. In the future, with optimized preparation conditions, it would be more sustainable option for patients. Several tests were performed on the hydrogel, to optimize its composition, in particular the most appropriate concentration of HA to include in the hydrogel itself. Tests on the nanocrystals to assess their purity and crystallinity as well the particle size were performed. These were followed by experiments to compare hydrogels with two final HA percentages: 0.125% wt/vol and 0.25% wt/vol. The following analysis were performed: a stability test to study in vitro hydrogel degradation kinetics under physiological conditions; pH, homogeneity and polymerization assessments; a compression test to evaluate mechanical properties of the hydrogel, particularly the stiffness; a bioprintability test, by a hand-extrusion method, that assessed its capability to form fibers without merging, to form 3D constructs. All of these were pre-conditions to determine if they would behave well as a biomaterial ink and for future use on cell viability trials. The ultimate test was the bioprinting of the material where the parameters were optimized, to guarantee a successful reproduction of the printed structures every time. Results showed that the biomaterial with the best concentration of SYN_HA was the 0.125% wt/vol one, as it had the most satisfactory results in all tests performed, confirming it can be used for bioprinting purposes.
- Implications of socio-cultural pressure for a thin body image on avoidance of social interaction and on corrective, compensatory or compulsive shopping behaviourPublication . Azevedo, António; Azevedo, Ângela SáThis paper aims to discuss the implications of body talk and socio-cultural pressure for the internalisation of a thin body image in purchase decisions, shopping habits and other outcomes of body dissatisfaction, in particular the proneness to avoid human/social interaction in retail contexts and proneness to engage in corrective, compensatory or compulsive shopping behaviour. This paper conducted an online questionnaire that measured the following constructs: body mass index; Socio-cultural Attitudes Towards Appearance Scale-4 (SATAQ-4), Body Appreciation Scale (BAS-2), Acceptance of Cosmetic Surgery Scale (ACSS), Compulsive Buying Follow-up Scale (CBFS), proneness to avoid social interaction in retail contexts, and the intention to purchase a list of products and services as a compensation for body dissatisfaction. A structural equations model supported the hypotheses proposing the influence of BAS-2 and SATAQ-4 (the internalisation of thin/athletic body and the social comparison induced by family, peers and media) upon the outcomes of social-interaction avoidance, ACSS and CBFS. Nevertheless, BAS-2 only influences social-interaction avoidance. This paper provides several recommendations to brand managers highlighting the social responsibility role of brand advertising in enhancing positive body appreciation, mitigating the psychological damage caused by socio-cultural pressure and preventing the stigmatisation bias against obese people.
- Relação entre abuso tradicional e ciberabuso no namoro, depressão e ideação suicida em jovens dos 18 aos 25 anosPublication . Gonçalves, Daniela Filipa Fernandes; Maia, Berta Maria Marinho RodriguesIntrodução: O abuso tradicional no namoro e o ciberabuso revelam-se um crescente problema social, dada a sua relação com o aumento de depressão e ideação suicida. Objetivo: Explorar a relação entre abuso tradicional e ciberabuso no namoro e a relação destes com a depressão e ideação suicida em jovens. Método: A amostra foi constituída por jovens Portugueses dos 18 e 25 anos, que preencheram um Questionário Sociodemográfico, o Questionário sobre Ciberabuso no Namoro, o Inventário de Conflitos na Relação de Namoro de Adolescentes, o Inventário de Avaliação Clínica da Depressão e o Questionário de Comportamentos Suicidários – Revisto. Resultados: Foi encontrada uma correlação significativa entre abuso tradicional e ciberabuso, entre abuso tradicional, depressão e ideação suicida e entre ciberabuso e depressão. Não foi encontrada uma correlação entre ciberabuso e ideação suicida. Verificou-se também diferenças entre sexos no que toca à vitimização por agressão direta, à utilização de estratégias de resolução de conflitos abusivas e positivas pelo parceiro. Encontrou-se também um maior relatado de abuso tradicional do tipo emocional. Para além disto, foi sexo masculino quem mais relatou atos de violência pelo parceiro. A maioria dos sujeitos foi vítima de ciberabuso, mas também perpetuador. Não se verificam diferenças em função do sexo na depressão e ideação suicida. Contudo, a maioria dos sujeitos da amostra também não apresenta indicadores de depressão nem de ideação suicida. Por fim, verificou-se uma correlação entre testemunhar violência no contexto familiar e utilização de estratégias de conflito abusivas.