Mechanical modelling of capacitive RF MEMS shunt switches

The mechanical response of a RF MEMS shunt connected switch in coplanar waveguide configuration has been studied by using both an uni-dimensional approach based on analytical equations and a Finite Element Method (FEM) with commercial software simulations. The analytical model, developed by means of a MATHCAD program, has been used to predict the dynamics of the device, mainly taking into account its re-configuration time and the energy balance involved in the actuation and in the de-actuation mechanisms. After that, 2D and 3D simulations have been performed to get the really deformed shape of the bridge, depending on the central and lateral actuation of the suspended beam. After that, 2D and 3D simulations have been performed by a central and lateral actuation of the suspended beam to get the really deformed shape of the bridge. Theoretical and experimental results about the threshold voltage and the response time of the device confirm the validity of the proposed modeling.     

Narrow-band filtering by means of triangular meta-material resonators based on RF MEMS cantilevers in CPW configuration

Microsystem Technologies - Triangular resonators, designed by using Radio Frequency Micro Electro Mechanical Systems (RF MEMS) cantilevers in coplanar waveguide (CPW) configuration, have been...     

Polypropylene‐based composites reinforced with textile wastes

The present work describes the preparation of polypropylene composites reinforced with cotton fibers, which were obtained from textile waste. The cellulosic fibers were bleached and then chemically modified on the surface using acetylation or silanization methods. Fourier transform infrared spectroscopy analysis and energy dispersive X‐ray spectroscopy confirmed the efficiency of both treatments. Results of thermal degradation by thermogravimetric analysis (TGA) of treated fibers indicated that the acetylated ones decreased thermal stability while the silanized fibers increased this property. The influence of the chemical modifications and fibers content in polypropylene‐based composites was studied by thermomechanical and mechanical properties (dynamic mechanical analysis and tensile tests) and thermal analyses (TGA and differential scanning calorimetry). The results showed that the addition of the obtained cellulose fibers in polypropylene caused increase of storage and Young's moduli, along with stress at break. Moreover, scanning electronic microscopy micrographs of cryofractured surfaces revealed stronger adhesion between fiber and matrix in the composites reinforced with the modified fibers. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45060.     

Clinical Considerations for a Family with Dilated Cardiomyopathy,Sudden Cardiac Death,and a Novel TTN Frameshift Mutation

Dilated cardiomyopathy (DCM) is the leading indication for heart transplantation. TTN gene truncating mutations account for about 25% of familial DCM cases and for 18% of sporadic DCM cases. The clinical relevance of specific variants in TTN has been difficult to determine because of the sheer size of the protein for which TTN encodes, as well as existing extensive genetic variation. Clinicians should communicate novel clinically-relevant variants and genotype–phenotype associations, so that animal studies evaluating the molecular mechanisms are always conducted with a focus on clinical significance. In the present study, we report for the first time the novel truncating heterozygous variant {"type":"entrez-nucleotide","attrs":{"text":"NM_001256850.1","term_id":"378925624","term_text":"NM_001256850.1"}}NM_001256850.1:c.72777_72783del (p.Phe24259Leufs*51) in the TTN gene and its association with DCM in a family with sudden death. This variant occurs in the A-band region of the sarcomere, in a known mutational hotspot of the gene. Truncating titin variants that occur in this region are the most common cause of DCM and have been rarely reported in asymptomatic individuals, differently from other pathogenic TTN gene variants. Further studies are warranted to better understand this particular clinically-relevant variant.     

Poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate)‐based biocomposites reinforced with kenaf fibers

Biodegradable thermoplastic‐based composites reinforced with kenaf fibers were prepared and characterized. Poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) (PHBV), produced by bacterial fermentation, was selected as polymeric matrix. To improve PHBV/fibers adhesion, low amount of a proper compatibilizing agent, obtained by grafting maleic anhydride onto PHBV, was added during matrix/fibers melt mixing (reactive blending). When compared with uncompatibilized composites, the presence of the compatibilizer induces a stronger interfacial adhesion and a more pronounced improvement of the mechanical properties. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Microglial Heterogeneity and Its Potential Role in Driving Phenotypic Diversity of Alzheimer’s Disease

Alzheimer’s disease (AD) is increasingly recognized as a highly heterogeneous disorder occurring under distinct clinical and neuropathological phenotypes. Despite the molecular determinants of such variability not being well defined yet, microglial cells may play a key role in this process by releasing distinct pro- and/or anti-inflammatory cytokines, potentially affecting the expression of the disease. We carried out a neuropathological and biochemical analysis on a series of AD brain samples, gathering evidence about the heterogeneous involvement of microglia in AD. The neuropathological studies showed differences concerning morphology, density and distribution of microglial cells among AD brains. Biochemical investigations showed increased brain levels of IL-4, IL-6, IL-13, CCL17, MMP-7 and CXCL13 in AD in comparison with control subjects. The molecular profiling achieved by measuring the brain levels of 25 inflammatory factors known to be involved in neuroinflammation allowed a stratification of the AD patients in three distinct “neuroinflammatory clusters”. These findings strengthen the relevance of neuroinflammation in AD pathogenesis suggesting, in particular, that the differential involvement of neuroinflammatory molecules released by microglial cells during the development of the disease may contribute to modulate the characteristics and the severity of the neuropathological changes, driving—at least in part—the AD phenotypic diversity.     

Experimental protocols for the assessment of redox thermodynamics of nonstoichiometric oxides: A case study of YMnO3-δ

The thermodynamics of reduction in variable valence oxides are important in a vast number of fields in which point defects, and in particular oxygen vacancies, control material functionality. Here, we present, by way of an example measurement of the material YMnO_3-δ, for which the vacancy formation energy has not been previously reported, best practices for material characterization. Sample mass is recorded by thermogravimetric analysis at temperatures from 600 to 1500°C under five different gas atmospheres, with oxygen partial pressure ranging from 0.081 to 7.66 × 10^–5 atm. Because YMnO_3-δ displays relatively small nonstoichiometry, less than 0.09, over the range of conditions examined, a large sample was required to record the modest mass changes. In the more oxidizing conditions, equilibrium behavior was recorded using a finite heating rate of 10°C min^–1. In the more reducing conditions, absolute mass changes with temperature were large such that the evolved oxygen increased the oxygen partial pressure in the sample vicinity, precluding equilibration under finite heating. Accordingly, a temperature-stepped protocol with long isothermal holds was employed. Analysis of the results from these stepped measurements required interpolation, which was carried out on the ln(δ) versus 1/T plane. In the nonpolar, centrosymmetric phase (P6₃/mcm and δ ≥ 0.016), the enthalpy of reduction was found to be 304 ± 4 kJ (mol-O)^–1, as averaged over the δ range 0.020–0.035. While YMnO_3-δ is known to incorporate oxygen excess in its ambient temperature, polar phase (P6₃cm), the conditions leading to such behavior were not included in this study.     

Efficacy of Polyunsaturated Fatty Acids (PUFAs) on Impulsive Behaviours and Aggressiveness in Psychiatric Disorders

It is the focus of increasing interest to investigate the effects of long-chain n-3 and long-chain n-6 polyunsaturated fatty acids (LC n-3 PUFAs; LC n-6 PUFAs) on psychiatric symptoms in a transdiagnostic perspective. There is some evidence that low levels of LC n-3 PUFAs and a higher ratio of LC n-6 to LC n-3 PUFAs in plasma and blood cells are associated with aggressive and impulsive behaviours. Therefore, implementation of LC n-3 PUFAs may produce positive effects on hostility, aggression, and impulsivity in both psychiatric and non-psychiatric samples across different stages of life. A possible mechanism of action of LC n-3 PUFAs in conditions characterized by a high level of impulsivity and aggression is due to the effect of these compounds on the serotonin system and membrane stability. Studies that evaluated the effects of LC n-3 PUFAs on impulsivity and aggressiveness indicated that addition of rather low doses of these agents to antipsychotic treatment might reduce agitation and violent behaviours in psychosis, attention deficit hyperactivity disorder, personality disorders, and impulsive control and conduct disorders. The present review is aimed at examining and discussing available data from recent trials on this topic.     

TNF-α Blocker Effect of Naringenin-Loaded Sericin Microparticles that Are Potentially Useful in the Treatment of Psoriasis

This study aims to evaluate the effect of combined use of the racemic flavanone Naringenin (NRG) and the protein sericin as TNF-α blockers. Sericin (SMs) and (R/S) NRG-loaded Sericin (SNRGMs) microparticles were prepared by spray-drying, characterized in terms of morphology and particle size distribution, and encapsulation efficiency was determined. Concerning morphology and particle size distribution of microparticles, results indicated that they were not affected by the presence of NRG. The encapsulation efficiency was almost quantitative (93%), thus proving that sericin can be advantageously loaded with (R/S) NRG. Biological evaluation of (R/S) NRG, SMs and SNRGMs was then performed in lipopolysaccharide (LPS)-stimulated human peripheral blood mononuclear cells (hPBMC). SNRGMs resulted cytotoxic at the higher dose used (200 μg/mL) and the effect was greater than (R/S) NRG alone. Moreover, even if sericin alone was not effective in suppressing LPS-induced serum TNF-α levels, SNRGMs loaded with 9.3% of (R/S) NRG were significantly more potent than (R/S) NRG alone. In summary, this study provides the proof of concept that sericin-based microspheres loaded with TNF-α-blockers could contribute to the down regulation of the cytokine and represents the starting point for the development of new topical formulations for the treatment of middle-stage psoriasis.