Background: New implant designs, such as resurfacing and stemless implants, have been developed to improve the long-term outcomes of the shoulder arthroplasty. However, it is not yet fully understood if their influence on the bone load distribution can compromise the long-term stability of the implant due to bone mass changes. Using three-dimensional finite element models, the aim of the present study was to analyse the bone remodelling process of the humerus after the introduction of resurfacing and stemless implants based on the Global C.A.P. and Sidus Stem-Free designs, respectively. Methods: The 3D geometric model of the humerus was generated from the CT data of the Visible Human Project and the resurfacing and stemless implants were modelled in Solidworks. Considering a native humerus model, a humerus model with the resurfacing implant, and a humerus model with the stemless implant, three finite element models were developed in Abaqus. Bone remodelling simulations were performed considering healthy and poor bone quality conditions. The loading condition considered comprised 6 load cases of standard shoulder movements, including muscle and joint reaction forces estimated by a multibody model of the upper limb. Findings: The results showed similar levels of bone resorption for the resurfacing and stemless implants for common humeral regions. The regions underneath the head of the resurfacing implant, unique to this design, showed the largest bone loss. For both implants, bone resorption was more pronounced for the poor bone quality condition than for the healthy bone quality condition. Interpretation: The stemless implant lost less density at the fixation site, which might suggest that these implants may be better supported in the long-term than the resurfacing implants. However, further investigation is necessary to allow definite recommendations.

This paper presents the application of a topology optimization algorithm based in homogenization theory. Three examples in structural design will be solved numerically. The first two are formulated such that analytical solutions can also be developed. To obtain this goal, the microscopic structure that we considered is formed of laminates because for this type of composite materials there is an explicit dependence of the homogenized coefficients on the design variables. The last example regards bone remodelling. Here, where it is impossible to obtain the analytical solution, the applied algorithm produces numerical results which are in good agreement with Wolffs Law.

Fish are ectotherms and temperature plays a determinant role in their physiology, biology and ecology, and is a driver of seasonal responses. The present study assessed how thermal imprinting during embryonic and larval stages modified the response of adult fish to low water temperature. We targeted the gilthead sea bream, which develops a condition known as winter syndrome when it is exposed to low water temperatures. Eggs and larvae of sea bream were exposed to four different thermal regimes and then the response of the resulting adults to a low temperature challenge was assessed. Sea bream exposed to a high-low thermal regime as eggs and larvae (HLT; 22 degrees C until hatch and then 18 degrees C until larvae-juvenile transition) had increased plasma cortisol and lower sodium and potassium in response to a cold challenge compared with the other thermal history groups. Plasma glucose and osmolality were increased in cold-challenged HLT fish relative to the unchallenged HLT fish. Cold challenge modified bone homeostasis/responsiveness in the low-high thermal regime group (LHT) relative to other groups, and ocn, ogn1/2, igf1, gr and tr alpha/beta transcripts were all downregulated. In the low temperature group (LT) and HLT group challenged with a low temperature, alkaline phosphatase (ALP) and tartrate-resistant acid phosphatase (TRAP) activities were decreased relative to unchallenged groups, and bone calcium content also decreased in the LT group. Overall, the results indicate that thermal imprinting during early development of sea bream causes a change in the physiological response of adults to a cold challenge.

A osteoporose é uma patologia assintomática a nível do esqueleto, que se caracteriza pela perda de densidade mineral óssea e pela deterioração da microarquitectura do osso. Assim sendo, esta patologia tem como consequências o aumento da fragilidade óssea e o aumento da suscetibilidade a fraturas. Com o envelhecimento da população a nível global, a osteoporose constitui atualmente, um problema de Saúde Pública grave. Esta doença, afeta ambos os sexos, no entanto as pessoas mais afetadas por ela são as mulheres, essencialmente no período pós-menopausa. Atualmente o tratamento da osteoporose baseia-se no seu tratamento farmacológico associado a mudanças no estilo de vida, incluindo mudanças alimentares, suplementação alimentar e prática de exercício físico. Contudo, estima-se que cerca de 70% das mulheres abandonam o tratamento no primeiro ano devido aos efeitos secundários associados a este tratamento. Assim sendo, a fitoterapia pode constituir uma alternativa aos problemas causados pela osteoporose. De facto a presença de compostos flavonoides e outros constituintes presentes nas plantas têm demonstrado uma ação benéfica na prevenção e tratamento da osteoporose. Para corroborar este facto achámos pertinente orientar o nosso estudo para cinco plantas distintas e muito utilizadas no tratamento fitoterápico da osteoporose: a cavalinha (Equisetum arvense), o cártamo (Carthamus tinctorius L.), o ligustro (Ligustrum lucidum), a soja (Glycine max L.) e a cimicifuga (Cimicifuga racemosa L.).