Envelhecimento (in)ativo e desenvolvimento emocional em reclusos

Este projeto pretende apresentar o contributo do programa de Exercício Físico e do Desenvolvimento Emocional nos reclusos. Para isso optamos por desenvolver um estudo de carácter Quantitativo, Exploratório, Quasi - Experimental, Longitudinal e Descritivo. A amostra é constituída por 20 reclusos do Estabelecimento Prisional de Izeda, com idade média de 41,10±10,19 anos, distribuída entre os 24 e os 67 anos. Dos 20 reclusos, 9 foram designados para integrarem o Grupo de Investigação e os restantes o Grupo de Controlo. A seleção foi feita de forma aleatória. O Grupo de Investigação foi submetido a um programa de atividades de duas a três sessões semanais, durante 8 semanas, tendo cada sessão a duração de 1:15 Horas. Foi aplicada a escala EVCE e o questionário SF-36v2, com a complementaridade das avaliações do estado funcional dos reclusos. As características psicométrica obtidas na escala EVCE e no questionário SF-36v2 permitem-nos verificar que neste estudo se obtem uma boa consistência interna. Após a realização das sessões de intervenção, verificamos que não houve alterações estatisticamente significativas entre os parâmetros do Grupo de Controlo e o Grupo de Investigação. Desta forma, podemos concluir que o programa de intervenção teria melhores resultados se tivesse uma duração maior ao longo do tempo.This project aims to present the contribution of an Exercise Program and of an Emotional Development Program in prison. For this study we chose to develop a Quantitative Explorational, Quasi - Experimental, Descriptive and Longitudinal. The sample consists of 20 inmates of the Izeda Prison, with a mean age of 41.10± 10.19 years, distributed between 24 and 67 years. Of the 20 inmates, nine were appointed to serve on the Research Group and the remaining To the Control Group. The selection was done randomly. The Research Group has undergone program of activities two to three times per week for 8 weeks, with each session lasting 1h15m. EVCE scale and SF-36v2 were applied, the functional status of the inmates was assessed. The psychometric characteristics obtained in EVCE scale and SF-36v2 allow us to verify that this study gives a good internal consistency. After completion of intervention sessions, we found that there were no statistically significant changes between the parameters of the Control Group and Research Group. Thus, we can conclude that the intervention program would have better results if it had a longer duration over tim

Responsive Emulsions Stabilized by Stimuli-Sensitive Microgels: Emulsions with Special Non-Pickering Properties

Recent studies revealing the unique properties of microgel-stabilized responsive emulsions are discussed, and microgels are compared to classical rigid-particle Pickering stabilizers. Microgels are strongly swollen, lyophilic particles that become deformed at the oil–water interface and protrude only a little into the oil phase. Temperature- and pH-sensitive microgels allow us to prepare temperature- and pH-sensitive emulsions and thus enable us to prepare and break emulsions on demand. Although such emulsions are sensitive to pH, the stabilization of droplets is not due to electrostatic repulsion, instead the viscoelastic properties of the interface seem to dominate droplet stability. Being soft and porous, microgels behave distinctly differently from rigid particles at the interface: they are deformed and strongly flattened especially in the case of oil-in-water emulsions. The microgels are located mainly on the water side of the interface for both oil-in-water and water-in-oil emulsions. In contrast to rigid, solid particles, the behavior of microgels at oil–water interfaces does not depend only on the interfacial tension but also on the balance among the interfacial tension, swelling, elasticity, and deformability of the microgel, which needs to be considered. It is obvious that microgels as soft, porous particles are significantly different from classical rigid colloidal stabilizers in Pickering emulsions and we suggest avoiding the term Pickering emulsion when swollen microgels are employed. Microgel-stabilized emulsions require the development of new theoretical models to understand their properties. They open the door to new sophisticated applications

Responsive Emulsions Stabilized by Stimuli-Sensitive Microgels: Emulsions with Special Non-Pickering Properties

Recent studies revealing the unique properties of microgel-stabilized responsive emulsions are discussed, and microgels are compared to classical rigid-particle Pickering stabilizers. Microgels are strongly swollen, lyophilic particles that become deformed at the oil–water interface and protrude only a little into the oil phase. Temperature- and pH-sensitive microgels allow us to prepare temperature- and pH-sensitive emulsions and thus enable us to prepare and break emulsions on demand. Although such emulsions are sensitive to pH, the stabilization of droplets is not due to electrostatic repulsion, instead the viscoelastic properties of the interface seem to dominate droplet stability. Being soft and porous, microgels behave distinctly differently from rigid particles at the interface: they are deformed and strongly flattened especially in the case of oil-in-water emulsions. The microgels are located mainly on the water side of the interface for both oil-in-water and water-in-oil emulsions. In contrast to rigid, solid particles, the behavior of microgels at oil–water interfaces does not depend only on the interfacial tension but also on the balance among the interfacial tension, swelling, elasticity, and deformability of the microgel, which needs to be considered. It is obvious that microgels as soft, porous particles are significantly different from classical rigid colloidal stabilizers in Pickering emulsions and we suggest avoiding the term Pickering emulsion when swollen microgels are employed. Microgel-stabilized emulsions require the development of new theoretical models to understand their properties. They open the door to new sophisticated applications

Functional Microgels and Microgel Systems

ConspectusMicrogels are macromolecular networks swollen by the solvent in which they are dissolved. They are unique systems that are distinctly different from common colloids, such as, e.g., rigid nanoparticles, flexible macromolecules, micelles, or vesicles. The size of the microgel networks is in the range of several micrometers down to nanometers (then sometimes called “nanogels”). In a collapsed state, they might resemble hard colloids but they can still contain significant amounts of solvent. When swollen, they are soft and have a fuzzy surface with dangling chains. The presence of cross-links provides structural integrity, in contrast to linear and (hyper)­branched polymers. Obviously, the cross-linker content will allow control of whether microgels behave more “colloidal” or “macromolecular”.The combination of being soft and porous while still having a stable structure through the cross-linked network allows for designing microgels that have the same total chemical composition, but different properties due to a different architecture. Microgels based, e.g., on two monomers but have either statistical spatial distribution, or a core–shell or hollow-two-shell morphology will display very different properties. Microgels provide the possibility to introduce chemical functionality at different positions. Combining architectural diversity and compartmentalization of reactive groups enables thus short-range coexistence of otherwise instable combinations of chemical reactivity. The open microgel structure is beneficial for uptake-release purposes of active substances. In addition, the openness allows site-selective integration of active functionalities like reactive groups, charges, or markers by postmodification processes. The unique ability of microgels to retain their colloidal stability and swelling degree both in water and in many organic solvents allows use of different chemistries for the modification of microgel structure.The capability of microgels to adjust both their shape and volume in response to external stimuli (e.g., temperature, ionic strength and composition, pH, electrochemical stimulus, pressure, light) provides the opportunity to reversibly tune their physicochemical properties. From a physics point of view, microgels are particularly intriguing and challenging, since their <i>intra</i>particle properties are intimately linked to their <i>inter</i>particle behavior.Microgels, which reveal interface activity without necessarily being amphiphilic, develop even more complex behavior when located at fluid or solid interfaces: the sensitivity of microgels to various stimuli allows, e.g., the modulation of emulsion stability, adhesion, sensing, and filtration. Hence, we envision an ever-increasing relevance of microgels in these fields including biomedicine and process technology.In sum, microgels unite properties of very different classes of materials. Microgels can be based on very different (bio)­macromolecules such as, e.g., polysaccharides, peptides, or DNA, as well as on synthetic polymers. This Account focuses on synthetic microgels (mainly based on acrylamides); however, the general, fundamental features of microgels are independent of the chemical nature of the building moieties. Microgels allow combining features of chemical functionality, structural integrity, macromolecular architecture, adaptivity, permeability, and deformability in a unique way to include the “best” of the colloidal, polymeric, and surfactant worlds. This will open the door for novel applications in very different fields such as, e.g., in sensors, catalysis, and separation technology

Spatially Resolved Tracer Diffusion in Complex Responsive Hydrogels

Thermosensitive composite hydrogels that consist of a poly­(acrylamide) hydrogel matrix with embedded micrometer-sized poly­(<i>N</i>-isopropylacrylamide) microgel beads are promising models for complex, heterogeneous gels. We investigate the coupling of the microgel beads with the gel matrix and the formation of interpenetrating networks inside the microgels by confocal two-focus fluorescence correlation spectroscopy (2fFCS). This technique serves to study the effects of the heterogeneous structure of the composite hydrogels on the diffusive mobility of nanoscopic dextran tracers within the gels. Our investigations reveal that the formation of interpenetrating networks inside the embedded microgel beads depends on their cross-link density: whereas interpenetrating networks are formed inside weakly cross-linked beads, they are not formed inside strongly cross-linked beads. If the formation of interpenetrating networks occurs, the temperature-dependent swelling and deswelling of the beads is obstructed. In addition, the mobility of dextran tracers inside the embedded microgel beads is hindered compared to those in free beads and in the surrounding gel matrix. Surprisingly, the surrounding poly­(acrylamide) hydrogel matrix swells inhomogeneously when the embedded poly­(<i>N</i>-isopropylacrylamide) beads collapse upon heating. This indicates the formation of pores near the surface of the collapsed beads, offering promising means to tailor composite hydrogels for applications as membranes with tunable permeability. Our experiments also demonstrate the utility of 2fFCS to study spatially resolved diffusion in complex environments, which is of great interest in biomaterials research

Cononsolvency Revisited: Solvent Entrapment by <i>N</i>‑Isopropylacrylamide and <i>N</i>,<i>N</i>‑Diethylacrylamide Microgels in Different Water/Methanol Mixtures

Aqueous dispersions of homo- and copolymer microgels of <i>N</i>-isopropylacrylamide (NiPAm) and <i><i>N</i></i>,<i><i>N</i></i>-diethylacrylamide (DEAm) with different compositions are temperature-dependently studied by means of proton nuclear magnetic resonance spectroscopy (¹H NMR) and differential scanning calorimetry (DSC). Furthermore, the effect of varying the solvent composition by adding methanol is investigated. Methanol addition leads to a broadening of the thermally induced volume phase transition in case of NiPAm-containing samples, as confirmed by DSC. At the same time, the width of transition approaches the one of neat PDEAm. Two different solvent species, namely bulk-like and restricted solvent, are observed as separate lines in ¹H NMR experiments when the gels deswell. The restricted nature of the second species is affirmed by pulsed field gradient (PFG) NMR self-diffusion experiments. The temperature <i>T</i>_split from which on the restricted species is found cannot be directly related to the volume phase transition temperature determined by DSC. The difference between <i>T</i>_split and the DSC peak temperature changes depending on the NiPAm-content of the microgel. An increase in the shift difference between the two solvent signals with temperature indicates a continuous change of the restricted solvent environment. At even higher temperature, the shift difference of restricted and bulk solvent approaches asymptotically a constant value. In general, the observed effects of methanol addition are consistent with an increasing complexation of the amide protons of the microgel (originating from the NiPAm units) with methanol. In contrast, poly­(DEAm) does not show any anomaly concerning transition width and <i>T</i>_split upon methanol addition. This is attributed to the lack of amide protons. The results indicate that the presence of cononsolvency can be explained by the presence of the amide proton

Probing the Internal Heterogeneity of Responsive Microgels Adsorbed to an Interface by a Sharp SFM Tip: Comparing Core–Shell and Hollow Microgels

Microgels composed of thermoresponsive polymer poly­(<i>N</i>-isopropylacrylamide) (PNIPAM) are interfacial active. Their adsorption leads to deformation, causing conformational changes that have profound effects on the macroscopic properties of these films. Yet, methods to quantitatively probe the local density are lacking. We introduced scanning force microscopy (SFM) to quantitatively probe the internal structure of microgels physically adsorbed on a solid (SiO₂)/water interface. Using a sharp SFM tip, we investigated the two types of microgels: (i) core–shell microgels featuring a hard silica core and a PNIPAM shell and (ii) hollow microgels obtained by dissolution of the silica core. Thus, both systems have the same polymer network as the peripheral structure but a distinctly different internal structure, that is, a rigid core versus a void. By evaluating the force–distance curves, the force profile during insertion of the tip into the polymer network enables to determine a depth-dependent contact resistance, which closely correlates with the density profiles determined in solution by small-angle neutron scattering. We found that the cavity of the swollen hollow microgels is still present when adsorbed to the solid substrate. Remarkably, while currently used techniques such as colloidal probe or reflectometry only provide an average of the <i>z</i>-profile, the methodology introduced herein actually probes the real three-dimensional density profile, which is ultimately important to understand the macroscopic behavior of microgel films. This will bridge the gap between the colloidal probe experiments that deform the microgel globally and the insertion in which the disturbance is located near the tip

Electrostatic Interactions and Osmotic Pressure of Counterions Control the pH-Dependent Swelling and Collapse of Polyampholyte Microgels with Random Distribution of Ionizable Groups

In this work, different systems of colloidally stable, ampholytic microgels (μGs) based on poly­(<i>N</i>-vinyl­capro­lactam) and poly­(<i>N</i>-isopropyl­acryl­amide), wherein the anionic and cationic groups are randomly distributed, were investigated. Fourier transmission infrared spectroscopy and transmission electron microscopy confirmed the quantitative incorporation and random distribution of ionizable groups in μGs, respectively. The control of hydrodynamic radii and mechanical properties of polyampholyte μGs at different pH values was studied with dynamic light scattering and in situ atomic force microscopy. We have proposed a model of pH-dependent polyampholyte μG, which correctly describes the experimental data and explains physical reasons for the swelling and collapse of the μG at different pHs. In the case of a balanced μG (equal numbers of cationic and anionic groups), the size as a function of pH has a symmetric, V-like shape. Swelling of purely cationic μG at low pH or purely anionic μG at high pH is due to electrostatic repulsion of similarly charged groups, which appears as a result of partial escape of counterions. Also, osmotically active counterions (the counterions that are trapped within the μG) contribute to the swelling of the μG. In contrast, electrostatic interactions are responsible for the collapse of the μG at intermediate pH when the numbers of anionic and cationic groups are equal (stoichiometric ratio). The multipole attraction of the charged groups is caused by thermodynamic fluctuations, similar to the those observed in Debye–Hückel plasma. We have demonstrated that the higher the fraction of cationic and anionic groups, the more pronounced the swelling and collapse of the μG at different pHs

Dynamically Cross-Linked Self-Assembled Thermoresponsive Microgels with Homogeneous Internal Structures

The internal morphology of temperature-responsive degradable poly­(<i>N</i>-isopropylacrylamide) (PNIPAM) microgels formed via an aqueous self-assembly process based on hydrazide and aldehyde-functionalized PNIPAM oligomers is investigated. A combination of surface force measurements, small angle neutron scattering (SANS), and ultrasmall angle neutron scattering (USANS) was used to demonstrate that the self-assembled microgels have a homogeneously cross-linked internal structure. This result is surprising given the sequential addition process used to fabricate the microgels, which was expected to result in a densely cross-linked shell–diffuse core structure. The homogeneous internal structure identified is also significantly different than conventional microgels prepared via precipitation polymerization, which typically exhibit a diffuse shell–dense core structure. The homogeneous structure is hypothesized to result from the dynamic nature of the hydrazone cross-linking chemistry used to couple with the assembly conditions chosen that promote polymer interdiffusion. The lack of an internal cross-linking gradient within these degradable and monodisperse microgels is expected to facilitate more consistent drug release over time, improved optical properties, and other potential application benefits

How Hollow Are Thermoresponsive Hollow Nanogels?

A main challenge in colloid science is the development of smart delivery systems that store and protect actives from degradation and allow release in response to an external stimulus like temperature. Hollow nanogel capsules made of temperature-sensitive polymers are particularly promising materials. The stimuli-sensitive void size, shell thickness, and permeability determine cargo storage and its release behavior. Thus, determination and control of these morphological parameters are of outmost relevance for the design of new, functional drug delivery vehicles. Here we investigate quantitatively void size and shell thickness of hollow nanogels at different states of swelling by means of small-angle neutron scattering (SANS) employing contrast variation. We demonstrate the structure-sensitivity dilemma: hollow nanogels with a slightly cross-linked shell reveal distinct temperature sensitivity but possess nearly no void (14% of the initial core volume) and are thus hardly “hollow”. Nanogels with a stiff shell are indeed hollow (albeit with smaller void as compared to the core size of the template) but less temperature sensitive