The competitive adsorption of human proteins onto natural-based biomaterials

This study aims to further the understanding of nanoscale structures relevant for cellular recognition on contact and interaction with natural-based materials. The correlation between surface characteristics and protein adsorption from unitary and complex protein systems was investigated with respect to altering the bulk chemistry of the substrate material. Polymeric blends of starch and cellulose acetate, polycaprolactone (SPCL) and ethylene vinyl alcohol (SEVA-C) were used. Different proteins, bovine serum albumin, human serum albumin (HSA) and human fibronectin (HFN), were selected for this study. The construction of adsorption isotherms is an important starting point towards characterizing the interactions between surfaces and proteins. In this study, albumin adsorption isotherms fit the Freundlich model and were correlated with the chemistry and morphology of surfaces. In addition, protein distribution, quantification and competition were measured using fluorimetry and visualized by confocal microscopy. The analysis of unitary systems demonstrated that the adsorption of HSA was generally lower than that of HFN. In the latter case, SPCL and SEVA-C blends reached adsorption values of 97 and 89 per cent, respectively. In studying the co-adsorption of proteins, an increase in both HSA and HFN on SEVA-C surfaces was observed. SPCL showed no substantial increase in the adsorption of the proteins in competitive conditions. The similarity of these materials with other polysaccharide-based materials increases the relevance of the presented results. This study provides valuable information for the development of strategies towards the control of protein orientation and functionality as the availability of cell signalling epitopes for a broader family of materials that continue to be a significant component of this field of research.     

Infrared nanosecond laser effects on the formation of copper nanoparticles

For the first time copper nanoparticles were formed inside Cu ion-doped glass after infrared irradiation by a nanosecond laser and sucessive annealing at 700 °C for 1 h. The surface plasmon resonance was observed in the absorption spectra of copper nanoparticles. Their spectral position is in good agreement with the values predicted by Mie theory for the copper nanoparticles. The possible mechanisms responsible by the observed results are discussed.     

A Novel FGFR1 Missense Mutation in a Portuguese Family with Congenital Hypogonadotropic Hypogonadism

Congenital hypogonadotropic hypogonadism (CHH) is a rare reproductive endocrine disorder characterized by complete or partial failure of pubertal development and infertility due to deficiency of the gonadotropin-releasing hormone (GnRH). CHH has a significant clinical heterogeneity and can be caused by mutations in over 30 genes. The aim of this study was to investigate the genetic defect in two siblings with CHH. A woman with CHH associated with anosmia and her brother with normosmic CHH were investigated by whole exome sequencing. The genetic studies revealed a novel heterozygous missense mutation in the Fibroblast Growth Factor Receptor 1 (FGFR1) gene ({"type":"entrez-nucleotide","attrs":{"text":"NM_023110.3","term_id":"1732262558"}}NM_023110.3: c.242T>C, p.Ile81Thr) in the affected siblings and in their unaffected father. The mutation affected a conserved amino acid within the first Ig-like domain (D1) of the protein, was predicted to be pathogenic by structure and sequence-based prediction methods, and was absent in ethnically matched controls. These were consistent with a critical role for the identified missense mutation in the activity of the FGFR1 protein. In conclusion, our identification of a novel missense mutation of the FGFR1 gene associated with a variable expression and incomplete penetrance of CHH extends the known mutational spectrum of this gene and may contribute to the understanding of the pathogenesis of CHH.     

Thrombocytopenia-Absent Radius Syndrome: Descriptions of Three New Cases and a Novel Splicing Variant in RBM8A That Expands the Spectrum of Null Alleles

Thrombocytopenia-absent radius (TAR) syndrome is a rare congenital disorder characterized by the bilateral absence of the radius and thrombocytopenia, and sometimes by other skeletal, gastrointestinal, cardiac, and renal abnormalities. The underlying genetic defect is usually the compound inheritance of a microdeletion in 1q21.1 (null allele) and a low-frequency, non-coding single nucleotide variant (SNV) in the RBM8A gene (hypomorphic allele). We report three new cases from two unrelated families. The two siblings presented the common genotype, namely the compound heterozygosity for a 1q21.1 microdeletion and the hypomorphic SNV c.-21G>A in RBM8A, whereas the third, unrelated patient presented a rare genotype comprised by two RBM8A variants: c.-21G>A (hypomorphic allele) and a novel pathogenic variant, c.343-2A>G (null allele). Of the eight documented RBM8A variants identified in TAR syndrome patients, four have hypomorphic expression and four behave as null alleles. The present report expands the RBM8A null allele spectrum and corroborates the particularities of RBM8A involvement in TAR syndrome pathogenesis.     

Constrained Nonlinear‐Based Optimisation Applied to Fuzzy PID Controllers Tuning

This paper aims at studying the optimal Fuzzy Proportional–Integral– Derivative controllers' tuning problem by considering two different nonlinear constrained optimisation techniques. One relying on a Hessian‐based analytical approach, and the other based on a differential evolutionary method. In the case of offline implementation, two basic frameworks are under assessment, depending on the controller parameters to be adjusted. For online scaling factors and membership functions' width tuning, its implementation is based on the parallel computation paradigm. The performance index is described by a quadratic cost function, taking as arguments control errors and the increment of control actions. Constraints on the scaling factors, membership functions' width, as well as on the system inputs and outputs are also included in the optimisation problem. Experiments carried out on a benchmark system favour the offline joint optimisation based on the differential evolutionary approach of scaling factors and membership functions' width.     

Fuzzy controllers gains tuning: a constrained nonlinear optimization approach

This paper presents a methodology for tuning the gains of fuzzy proportional-integral controllers where the concept of closed-loop control system performance is explicitly taken into account. The fuzzy controller gains are found by solving a nonlinear constrained optimization problem considering the system’s dynamics described by a nonlinear model and a set of constraints on the controller gains, control actions and outputs. Experimental results collected on a test-bed show the pertinence of using the proposed tuning technique.     

Influence of type of compatibilizer on the rheological and mechanical behavior of LCP/TP blends under different stationary and nonstationary shear conditions

The addition of small amounts of liquid‐crystalline polymers to thermoplastics leads to the formation of in situ–reinforced materials, with improved processability and mechanical properties. Nevertheless, the lack of adhesion between the thermoplastic and the liquid‐crystalline polymer often occurs, thus requiring the use of compatibilizers. In this case, the results of several previous works show that there is an improvement of strength, usually accompanied by a decrease of toughness and, thus, the interest of LCP/TP blends for industrial applications will certainly increase if both strength and toughness are obtained. Additionally, the emphasis of previous studies has been on the evaluation of the properties of the blend under stationary conditions and not under non‐stationary ones, which are, in fact, those most relevant to processing sequences. Thus, the present work focuses on the influence of type of compatibilizer on the mechanical and rheological properties of polypropylene/LCP blends under nonstationary conditions. In terms of mechanical properties, the traditional increase of tensile strength was obtained for all compatibilizers, which was essentially due to the formation, during processing, of thinner and longer fibrils of LCP dispersed in the matrix than those observed for the noncompatibilized blends. Additionally, an improvement of the impact strength and flexural modulus was also observed for the blend in which a compatibilizer with an elastomeric nature was used. Rheologically, the experiments most sensitive to the structure were those performed in transient shear, with an increase of the transient stress (in the form of an overshoot) of different magnitudes being observed for the different compatibilizers. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 694–703, 2005     

Cardiovascular risk analysis by means of pulse morphology and clustering methodologies

The purpose of this study was the development of a clustering methodology to deal with arterial pressure waveform (APW) parameters to be used in the cardiovascular risk assessment. One hundred sixteen subjects were monitored and divided into two groups. The first one (23 hypertensive subjects) was analyzed using APW and biochemical parameters, while the remaining 93 healthy subjects were only evaluated through APW parameters. The expectation maximization (EM) and k-means algorithms were used in the cluster analysis, and the risk scores (the Framingham Risk Score (FRS), the Systematic COronary Risk Evaluation (SCORE) project, the Assessing cardiovascular risk using Scottish Intercollegiate Guidelines Network (ASSIGN) and the PROspective Cardiovascular Münster (PROCAM)), commonly used in clinical practice were selected to the cluster risk validation. The result from the clustering risk analysis showed a very significant correlation with ASSIGN (r = 0.582, p < 0.01) and a significant correlation with FRS (r = 0.458, p < 0.05). The results from the comparison of both groups also allowed to identify the cluster with higher cardiovascular risk in the healthy group. These results give new insights to explore this methodology in future scoring trials.     

Characterization of chitosan–whey protein films at acid pH

The capability to produce blend chitosan–whey protein films at acidic pH, carrying a high amount of protein, is demonstrated, even though under these conditions a pure whey protein film could not be obtained. The films are biphasic and characterized by a compositional gradient, with the downward film surface containing a lower amount of protein than the upward surface. The surface richer in protein was more hydrophobic than that richer in chitosan. The difference in composition and hydrophilicity between both surfaces increases with the amount of protein incorporated in the film. Increasing the protein amount decreased elongation at break and tensile strength but, in general, had little effect on water vapor permeability. Although some of the film functionality might be compromised due to the incompatibility between the polysaccharide and protein components within the film matrix, the blended films, especially those with intermediated protein amount, may have useful applications on those food systems where the edible films should break up during the cooking or mastication process.