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Excessive vibration problems related to building floors concerning the human comfort have been reported by several researchers in the past two decades. The reason for those vibrations is mainly related with the current trend for the design of slender and flexible structural systems, with the inherent low damping. Consequently, such floors are prone to resonant motion which may reach high vibration levels once their natural frequencies lie in the same range of the human induced forces. In this sense, the human activities, such as walking, jumping or bouncing have been described in some design guides by pure forces acting on the structure. This assumption has conducted to a more or less conservative structural design depending on the chosen loading model function. Recent studies have demonstrated that the use of biodynamics models in order to represent the human behaviour may lead to a more realistic, reasonable and economical design, as they take into account the human body dynamic properties. This paper aims at evaluating the body dynamic parameters by means of a force plate and an accelerometer mounted on the human body when a rhythmic activity (jumping) is developed. This way, experimental tests are carried out both on a rigid surface and on a vibrating floor so that the mass, spring and damping of the identified human biodynamic model can be obtained through an optimisation method. (C) 2017 The Authors. Published by Elsevier Ltd.

Bovine glycomacropeptide (GMP), derived from whey proteins, has been demonstrated to possess an interesting bioactivity that has attracted a lot of attention over the last few years. In particular, its ability to bind Vibrio cholerae and Escherichia coli enterotoxins, inhibit bacterial and viral adhesion, suppress gastric secretions, promote bifidobacterial growth and modulate immune system responses. Of these, protection against toxins, bacteria and viruses, and modulation of the immune system, are the most promising applications for this bioactive dairy macropeptide. The development of strategies that may allow its structural and functional stabilization via nanoencapsulation within multiple emulsions may increase its food and biopharmaceutical applicabilities. In this research effort, bovine GMP was (thermodynamically) stabilized via entrapment within water-in-oil-in-water (W/O/W) multiple emulsions aiming at mimicking the multifunctional design of biology, with several lipid matrices, and stabilizing layer compositions. Due to their compartimentalized internal structure, multiple emulsions are ideal for encapsulation since they can carry both polar and non-polar (bio)molecules. The composition of the stabilizing layer of the nanosystem was changed by using different poloxamers and proportions of lecithin. Physicochemical characterization of the optimized GMP-encasing nanovesicle formulations encompassed determination of Zeta potential and particle hydrodynamic size over storage time, surface morphology via CRYO-SEM, and microcalorimetric analysis via DSC.

In the recent past years, bacteriophage research has experienced a renaissance due to their potential application in the pharmaceutical field, especially with the increase of bacterial resistance to antibiotics and the possibility to take part in new methods of early detection and diagnosis of bacterial infections. In that context, the structural and functional stabilization of bacteriophages using biopolymeric microporous hydrogels represents a promising research focus with a broad potential biomedical/ biopharmaceutical application. The scope of this work was to develop biopolymeric non-toxic phage-hydrogels of agar and sodium alginate, obtained at neutral pH and mild polymerization conditions, in order to offer adequate characteristics to the maintenance of phage’s lytic activity. Disc-like phage-hydrogels were prepared, with a phage and polymer concentration of 1.3x108 PFU/ml and 1.5% (w/v), respectively. Regarding the alginate hydrogels, CaCO3 (22.5 mM) and GDL (48 mM) were also included in the formulation. Agar hydrogels were prepared naturally by jellification, as a function of temperature lowering, and alginate hydrogels were prepared by internal gelation. The matrices were inoculated with a suspension of susceptible (host) bacteria and incubated at 37 ºC for 24h. Observation of bacterial lawn’s lysis demonstrated that bacteriophages kept their lytic activity, being the method of physical entrapment able to promote their stabilization. Cryo-SEM analysis revealed that both types of phage-hydrogels present interconnective microporous network, which guaranties a facilitated access of the phages to the bacteria, ensuring an efficient lysis of the host bacteria present in the surface of the hydrogels.The developed hydrogels also present appropriate physical and chemical properties for a wider variety of applications in the field of pharmaceutical sciences, such as controlled release of (macro)molecules, cell immobilization and 3D support for tissue regeneration.

Inflammatory diseases that occur in the pharynx and involving both the adenoids and tonsils are important not only for being very frequent, but also because they often require minor surgery for their resolution. These structures have immunological functions leading to production of antibodies, and work in the local immunity of the pharynx and protection of the entire body. The most common etiologic agent of sore throats is Streptococcus pyogenes, an important pathogen of the beta-hemolytic group A which causes streptococcal pharyngitis. The emergence of antibiotic-resistant bacterial strains and the poor penetration of chemical antibiotics in bacterial biofilms raise the need for safe and effective options of antimicrobial treatment. The application of bacteriophages (or cocktails therefrom) has been proposed as an alternative (or complement) to conventional chemical antibiotics, allowing the release of natural predators of bacteria directly on these biofilms. The major advantage of bacteriophage-based antibiotherapy relative to its conventional chemical counterpart is that bacteriophages replicate at the site of infection, being available in abundance where they are needed the most. When compared with chemical antibiotics, bacteriophages have other important advantages: (i) strong tissue permeability, (ii) bacteriophage concentration remains high at the focus of infection, continuously increasing with bacterial (host) presence, (iii) elimination of the focus of infection occurs only after eradication of the host bacterium, (iv) bacteriophages are fully compatible with antibiotics and may act synergistically, (v) they are specific against the target bacteria, (vi) have a superior ability to penetrate bacterial biofilms, inducing production of enzymes that hydrolyze the biofilm polymeric matrix, (vii) although bacteria can develop resistance to bacteriophages, isolation of new lytic bacteriophages is much simpler and cheaper than developing a new chemical antibiotic. In this research effort, development of a biotechnological process for the inhalational administration of a bacteriophage cocktail (endotoxin free) was pursued, using strategies of nanoencapsulation within lipid nanovesicles (as forms of protection for the bacteriophage against the immune system) to treat infectious pathologies such as pharyngo-tonsillitis caused by Streptococcus pyogenes. This method of targeting may have a high potential for the treatment of bacterial infections of the respiratory tract, since inhalation therapy is considered to be favorable to certain respiratory infections because the aerosol is delivered directly at the site of infection, accelerating the action of bacterial predators. Additionally, a smaller amount of bioactive substance is needed, thus preventing or reducing possible side effects. As a proof of concept for the nanoencapsulation strategy, and since there is not yet available a strictly lytic bacteriophage cocktail for Streptococcus pyogenes, a well-defined and characterized bacteriophage was utilized, viz. bacteriophage T4. Water-in-oil-in-water (W/O/W) multiple emulsions are nanosystems in which dispersions of small water droplets within larger oil droplets are themselves dispersed in a continuous aqueous phase. Due to their compartimentalized internal structure, multiple emulsions present important advantages over simple O/W emulsions for encapsulation of biomolecules, such as the ability to carry both polar and non-polar molecules, and a better control over releasing of therapeutic molecules. T4 bacteriophage was entrapped within W/O/W multiple nanoemulsions, aiming at mimicking the multifunctional design of biology, optimized with several lipid matrices, poloxamers and stabilizing layer compositions. Physicochemical characterization of the optimized bacteriophage-encasing nanovesicle formulations encompassed determination of particle size, size distribution and particle charge, via Zeta potential analysis, surface morphology via CRYO-SEM, and thermal analysis via DSC, whereas antimicrobial activity of the nanoemulsions produced were evaluated via the “spot-test” using appropriate bacterial cultures.

Infectious bacterial diseases still remain the main cause of human premature deaths, especially in developing countries. The emergence and spread of pathogenic bacteria resistant to many chemical antibiotics (multidrugresistant strains) have created the need for the development of novel therapeutic agents. Bacteriophages have proven to be an interesting and effective alternative in the management of persistent bacterial infections where conventional chemical antibiotherapies fail. The lethality and specificity of bacteriophages for specific bacteria, their ability to replicate within bacterial hosts and safety of these human-friendly viruses makes them highly lethal antibacterial agents, besides being efficient and relatively cost-effective. Group A streptococci (GAS) are serious human pathogens that cause infections ranging from mild pharyngitis, tonsillitis, to chronic rheumatic heart disease and, in some cases, severe streptococcal toxic shock syndrome and necrotizing fasciitis. The frequency and severity of GAS infections has been increasing over the last decades, which has promoted extensive research on the improvement of naturally occurring antimicrobials as alternatives to their conventional chemical counterparts. In this research effort, development and optimization of a biotechnological process for the inhalational administration of a bacteriophage was pursued, using strategies of nanoencapsulation within lipid nanovesicles. This method of targeting may have a high potential for the treatment of bacterial infections of the respiratory tract, caused mainly by Streptococcus pyogenes. As a proof-of-concept for the nanoencapsulation strategy, and since there is not yet available a strictly lytic bacteriophage cocktail for Streptococcus pyogenes, a well-defined and characterized bacteriophage was utilized, viz. bacteriophage T4. Water-in-oil-in-water (W/O/W) multiple emulsions are nanosystems in which dispersions of small water droplets within larger oil droplets are themselves dispersed in a continuous aqueous phase. Due to their compartimentalized internal structure, multiple emulsions present important advantages over simple O/W emulsions for encapsulation of biomolecules, such as the ability to carry both polar and non-polar molecules, and a better control over releasing of therapeutic molecules. Bacteriophage T4 was accordingly entrapped within W/O/W multiple nanoemulsions, aiming at mimicking the multifunctional design of biology, optimized with several lipid matrices, poloxamers and stabilizing layer compositions. Physicochemical characterization of the optimized bacteriophage-encasing nanovesicle formulations encompassed determination of particle (hydrodynamic) size, size distribution and particle charge (Zeta potential), via Dynamic Light Scattering analysis, surface morphology via Cryo-SEM, and thermal analysis via DSC, whereas antimicrobial activity of the nanoemulsions produced were evaluated via the “spot-test” using appropriate bacterial cultures.