Vidros bioactivos isentos de alcalinos para regeneração óssea

Doutoramento em Ciência e Engenharia dos MateriaisBioactive glasses and glass-ceramics are a class of third generation biomaterials which elicit a special response on their surface when in contact with biological fluids, leading to strong bonding to living tissues. The purpose of the present study was to develop diopside based alkali-free bioactive glasses in order to achieve good sintering behaviour, high bioactivity, and a dissolution/ degradation rates compatible with the target applications in bone regeneration and tissue engineering. Another aim was to understand the structure-property relationships in the investigated bioactive glasses. In this quest, various glass compositions within the Diopside (CaMgSi2O6) – Fluorapatite (Ca5(PO4)3F) – Tricalcium phosphate (3CaO•P2O5) system have been investigated. All the glasses were prepared by melt-quenching technique and characterized by a wide array of complementary characterization techniques. The glass-ceramics were produced by sintering of glass powders compacts followed by a suitable heat treatment to promote the nucleation and crystallization phenomena. Furthermore, selected parent glass compositions were doped with several functional ions and an attempt to understand their effects on the glass structure, sintering ability and on the in vitro bio-degradation and biomineralization behaviours of the glasses was made. The effects of the same variables on the devitrification (nucleation and crystallization) behaviour of glasses to form bioactive glass-ceramics were also investigated. Some of the glasses exhibited high bio-mineralization rates, expressed by the formation of a surface hydroxyapatite layer within 1–12 h of immersion in a simulated body fluid (SBF) solution. All the glasses showed relatively lower degradation rates in comparison to that of 45S5 Bioglass®. Some of the glasses showed very good in vitro behaviour and the glasses co-doped with zinc and strontium showed an in vitro dose dependent behaviour. The as-designed bioactive glasses and glass–ceramic materials are excellent candidates for applications in bone regeneration and for the fabrication of scaffolds for tissue engineering.Os vidros e vitrocerâmicos bioactivos fazem parte da chamada terceira geração de biomateriais, i.e., materiais que estimulam uma resposta especial quando em contacto com fluidos biológicos, capaz de conduzir ao estabelecimento de ligações fortes entre a sua superfície e os tecidos vivos. O presente estudo visou o estudo e desenvolvimento de vidros bioactivos à base de diópsido e isentos de metais alcalinos que apresentem um bom comportamento na sinterização, elevados índices de bioactividade, e taxas de dissolução / degradação compatíveis com as almejadas aplicações em regeneração óssea e em engenharia de tecidos. Procurou-se ainda entender as relações entre a estrutura e as propriedades dos vidros bioactivos estudados. De acordo com esta perspectiva, estudaram-se várias composições de vidros bioactivos pertencentes ao sistema Diópsido (CaMgSi2O6) – Fluorapatite (Ca5(PO4)3F) – Fosfato de tricálcico (3CaO•P2O5). Todas as composições vítreas foram preparados por fusão, seguida de fritagem em água fria, e caracterizados através de um conjunto de técnicas complementares de caracterização. Os vitrocerâmicos foram obtidos por sinterização das fritas de vidro moídas e compactadas, seguida de tratamento térmico adequado para promover os fenómenos de nucleação e cristalização. Além disso, algumas composições vítreas seleccionadas foram dopadas com vários iões funcionais e os seus efeitos na estrutura vítrea, na sua propensão para a sinterização, e nos comportamentos in vitro em termos de biodegradação e bio-mineralização foram avaliados. Os efeitos das mesmas variáveis no processo de devitrificação (nucleação e cristalização) dos vidros e formação de materiais vitrocerâmicos foram também investigados. Algumas composições de vítreas apresentaram taxas de bio-mineralização elevadas, expressas através da formação de camadas superficiais de hidroxiapatite após 1-12 h de imersão num fluido fisiológico simulado (SBF). Todas as composições vítreas apresentaram taxas de degradação mais baixas quando comparadas com a do 45S5 Bioglass®. Alguns vidros bioactivos revelaram comportamentos in vitro excelentes, sendo a taxa de biomineralização dos co-dopados com zinco e estrôncio dependente da dose incorporada de dopantes. Os materiais estudados demostraram boa aptidão para aplicações em regeneração óssea e para o fabrico de estruturas de suporte em engenharia de tecidos

Elegant Aging Through Endocrine Optimization

Elegant Aging Through Endocrine Optimizatio

Neonatal dengue with enterococcus sepsis

Dengue infection is possible in all the three trimesters of pregnancy and is associated with various maternal and neonatal complications. The occurrence of subclinical infections may lend further confusion to the situation. Here, we report a case of neonatal dengue diagnosed with dengue NS1 antigen positive and IgM positive followed by secondary sepsis with Enterococcus faecium. Case studies like these may contribute to increased awareness of the suspicion of the associated life-threatening infections that can occur with neonatal dengue, their manifestations, and the management, thus improving their outcome

MHD Flow Heat and Mass Transfer of Micropolar Fluid over a Nonlinear Stretching Sheet with Variable Micro Inertia Density, Heat Flux and Chemical Reaction in a Non-darcy Porous Medium

This paper investigates the two dimensional flow, heat and mass transfer of chemically reacting Micropolar fluid over a non-linear stretching sheet with variable heat flux in a non-darcy porous medium. The rate of chemical reaction is assumed to be constant throughout the fluid i.e. homogenous. Using a similarity transformation, the governing partial differential equations are transformed into a system of ordinary differential equation, which is then solved using Finite element method. Numerical results regarding local Nussult No. are shown graphically with Magnetic number (ܰ݉௫) for variation in heat transfer exponent (n). This study also analyzes the effect of velocity exponent m, heat transfer exponent n, material parameter K, Magnetic Number(ܰ݉௫)Darcy NumberDax, Forchheimer Number Nfx, Prandtl number Pr, Schmidt Number Sc and Chemical reaction rate parameter x on velocity, microrotation, temperature and concentration profiles. Velocity exponent m has a positive effect on the velocity, temperature and concentration profiles while microrotation decreases as m increases. Graphical results shows that the thermal boundary layer thickness decreases at and near the wall with the increase in heat flux exponent n. Also an increase in K leads to a decrease in skin friction parameter as well as the wall couple stress

Choosing Glucose-lowering Therapy: A Collaborative Choice Model

Diabetes care is challenging, and the increasing number of available therapeutic options has made it even more complex. Moreover, with an increasing prevalence across the world, it needs to be managed right from the primary care level to a quaternary care hospital. This calls for an easy-to-use algorithm that can be used by a general practitioner, who is often the first contact of a patient to manage diabetes in many countries. There are multiple models to assist in choice of pharmacotherapy, and these have evolved over time. We propose a user-friendly collaborative choice, as an aid to clinical decision-making. This alliterative framework supplements and strengthens existing guidance, by creating a comprehensive, yet simple, thought process for the diabetes care professional

Disinfection by 1% sodium hypochlorite through cold fogging: an innovative appropriate technology against COVID-19 in public health

Background: SARS-CoV-2 is an enveloped virus with a fragile outer lipid envelope that makes it more susceptible to disinfectants compared to non-enveloped viruses. In this article, dispensation through cold Fogger was innovated as a measure against aerosol-based transmission of COVID-19 in large, enclosed spaces like hospitals, nursing homes, isolation centers and quarantine facilities.Methods: Ecological exploratory study, to ours effectiveness of 1% sodium hypochlorite through cold fogging against SARS COV-2 technology. Study setting included medical college in Western Maharashtra and the selected COVID-19 hospitals. The data was collated in MS excel and analysed using IBM SPSS version 23.0.Results: Average of 2.9 % HCWs got infected in hospitals where this innovation was used to disinfect, as compared to infections rates of 21.5% and 14.7% in other premier health institutes. There was strong negative correlation between percentage of health care infected and liters of sodium hypochlorite used with R2=0.56. Also, on applying Spearman correlation coefficient there was good negative correlation (-0.8).Conclusions: This appropriate technology has shown significant reduction in infection, with antecedent benefit of decreased morbidity and mortality of precious trained manpower. It gives much better dis-infection at 07 times less the cost and can be conveniently used for dis-infection against COVID-19 at the very periphery of primary health care delivery done at Sub-centres and PHCs