The effect of the conditions of electrodeposition on the capacitive properties of dinitrobenzoyl-derivative polypyrrole films

Films of poly[(R)-(−)-3-(1-pyrrolyl)propyl-N-(3,5-dinitrobenzoyl)-α-phenylglycinate] (polyDNBP) were deposited, using the galvanostatic method, onto indium tin oxide electrodes in the presence of the electrolytes tetrabutylammonium tetrafluoro-borate [(C₄H₉)₄NBF₄] or LiClO₄. Atomic force microscopy revealed that polyDNBP/(C₄H₉)₄NBF₄ films exhibited a grainy morphology with higher roughness and greater superficial area than polyDNBP/LiClO₄ films. Moreover, polyDNBP/(C₄H₉)₄NBF₄ films exhibited a higher capacitive electrochemical response when characterised in LiClO₄ rather than in (C₄H₉)₄NBF₄. Since polyDNBP films exhibit both n- and p-doping, they may have considerable potential application as electrodes in type III capacitor assemblies.     

The balance of give and take in caregiver–partner relationships: An examination of self-perceived burden, relationship equity, and quality of life from the perspective of care recipients following stroke.

Purpose: We examined the sense of being a burden to others or self-perceived burden (SPB) in people with stroke. Method: A mail survey was completed by 57 former inpatients and their partner caregivers. The care recipient survey included measures of functional status, quality of life, marital satisfaction, equity in the relationship, and psychological distress, as well as SPB using the Self-Perceived Burden Scale (SPBS; Cousineau, McDowell, Hotz, & Hébert, 2003). The caregiver survey included similar measures in addition to a caregiver burden measure. Results: SPB was found to be a prevalent and distressing concern. SPBS scores correlated with measures of functional status and mood; however, the correlations were highest for measures of family roles and work/productivity. Using equity theory as a basis to examine the SPB construct, care recipients who perceived themselves as overbenefiting from the relationship had significantly higher SPB scores than those whose relationship was viewed as equitable or underbenefiting. Conclusions: For some receiving care from a partner after stroke is associated SPB. This sense of burden is related to changes in help-seeking behavior, quality of life, and distress. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Experimental Characterization of the Interaction between the N-Terminal SH3 Domain of Crkl and C3G

Crkl is a protein involved in the onset of several cancer pathologies that exerts its function only through its protein–protein interaction domains, a SH2 domain and two SH3 domains. SH3 domains are small protein interaction modules that mediate the binding and recognition of proline-rich sequences. One of the main physiological interactors of Crkl is C3G (also known as RAPGEF1), an interaction with key implications in regulating cellular growth and differentiation, cell morphogenesis and adhesion processes. Thus, understanding the interaction between Crkl and C3G is fundamental to gaining information about the molecular determinants of the several cancer pathologies in which these proteins are involved. In this paper, through a combination of fast kinetics at different experimental conditions and site-directed mutagenesis, we characterize the binding reaction between the N-SH3 domain of Crkl and a peptide mimicking a specific portion of C3G. Our results show a clear effect of pH on the stability of the complex, due to the protonation of negatively charged residues in the binding pocket of N-SH3. Our results are discussed under the light of previous work on SH3 domains.     

Primary and Secondary Cone Cell Death Mechanisms in Inherited Retinal Diseases and Potential Treatment Options

Inherited retinal diseases (IRDs) are a leading cause of blindness. To date, 260 disease-causing genes have been identified, but there is currently a lack of available and effective treatment options. Cone photoreceptors are responsible for daylight vision but are highly susceptible to disease progression, the loss of cone-mediated vision having the highest impact on the quality of life of IRD patients. Cone degeneration can occur either directly via mutations in cone-specific genes (primary cone death), or indirectly via the primary degeneration of rods followed by subsequent degeneration of cones (secondary cone death). How cones degenerate as a result of pathological mutations remains unclear, hindering the development of effective therapies for IRDs. This review aims to highlight similarities and differences between primary and secondary cone cell death in inherited retinal diseases in order to better define cone death mechanisms and further identify potential treatment options.     

Microstructure and electrical properties of zirconia and composite nanostructured ceramics sintered by different methods

The aim of this study is the preparation and characterization of dense cubic zirconia ceramics and zirconia nanocomposites (reinforced with 5 wt% alumina). The powders were obtained through sol–gel methods and densified using classical sintering and spark plasma sintering (SPS) methods. The obtained ceramics were characterized through X-ray diffraction, scanning electron microscopy and impedance spectroscopy at room and high temperature. The average grain size of cubic zirconia particles was found to be approximately 8 and 2.5 μm for the classical sintering and 99 nm for SPS. The alumina particles in composites have an average grain size of 0.7 μm for classical sintering and 53 nm for SPS ones. The total conductivity for nanocomposites sintered through both methods was also determined.     

Gut microbiota and probiotics: Focus on diabetes mellitus

The characterization of gut microbiota has become an important area of research in several clinical conditions, including type 2 diabetes (T2DM). Changes in the composition and/or metabolic activity of the gut microbiota can contribute to human health. Thus, this review discusses the effects of probiotics and gut microbiota on metabolic control in these individuals. Relevant studies were obtained from electronic databases such as PubMed/Medline and ISI Web of Science. The main probiotics used in these studies belonged to the genera Lactobacillus and Bifidobacterium. The authors found seven randomized placebo-controlled clinical trials and 13 experimental studies directly related to the effect of probiotics on metabolic control in the context of T2DM. The hypothesis that gut microbiota plays a role in the development of diabetes indicates an important beginning, and the potential of probiotics to prevent and reduce the severity of T2DM is better observed in animal studies. In clinical trials, the use of probiotics in glycemic control presented conflicting results, and only few studies have attempted to evaluate factors that justify metabolic changes, such as markers of oxidative stress, inflammation, and incretins. Thus, further research is needed to assess the effects of probiotics in the metabolism of diabetic individuals, as well as the main mechanisms involved in this complex relationship.     

Fluidic Force Microscopy and Atomic Force Microscopy Unveil New Insights into the Interactions of Preosteoblasts with 3D-Printed Submicron Patterns

Physical patterns represent potential surface cues for promoting osteogenic differentiation of stem cells and improving osseointegration of orthopedic implants. Understanding the early cell–surface interactions and their effects on late cellular functions is essential for a rational design of such topographies, yet still elusive. In this work, fluidic force microscopy (FluidFM) and atomic force microscopy (AFM) combined with optical and electron microscopy are used to quantitatively investigate the interaction of preosteoblasts with 3D-printed patterns after 4 and 24 h of culture. The patterns consist of pillars with the same diameter (200 nm) and interspace (700 nm) but distinct heights (500 and 1000 nm) and osteogenic properties. FluidFM reveals a higher cell adhesion strength after 24 h of culture on the taller pillars (32 ± 7 kPa versus 21.5 ± 12.5 kPa). This is associated with attachment of cells partly on the sidewalls of these pillars, thus requiring larger normal forces for detachment. Furthermore, the higher resistance to shear forces observed for these cells indicates an enhanced anchorage and can be related to the persistence and stability of lamellipodia. The study explains the differential cell adhesion behavior induced by different pillar heights, enabling advancements in the rational design of osteogenic patterns.     

Magnetoresistance in Sn-Doped In2O3 Nanowires

In this work, we present transport measurements of individual Sn-doped In₂O₃ nanowires as a function of temperature and magnetic field. The results showed a localized character of the resistivity at low temperatures as evidenced by the presence of a negative temperature coefficient resistance in temperatures lower than 77 K. The weak localization was pointed as the mechanism responsible by the negative temperature coefficient of the resistance at low temperatures.     

Nano-assembled Pd catalysts on MgO thin films

Cluster-assembled materials open fascinating new routes for tuning physical and chemical properties by changing cluster size and often behave completely differently than their bulk analogues. By depositing gas phase Pd clusters on MgO thin films, model catalysts are fabricated which exhibit remarkable catalytic activity. In contrast to the high selectivity of Pd (111) surfaces for the cyclotrimerization of acetylene to benzene, small supported Pd_n clusters reveal a strongly size-dependent selectivity and catalyse the formation of benzene as well as of other hydrocarbons. The understanding at the atomistic level of the observed processes has been obtained by means of first-principles quantum–mechanical simulations. The theoretical studies have shown the importance of the surface defects of the oxide substrate in stabilizing the supported clusters but also in promoting their catalytic activity. For instance, Pd atoms bound at the regular sites of the MgO (100) terraces do not promote the acetylene to benzene conversion while they become active catalysts when bound at oxygen vacancies (F centers).