Experimental characterization of a Circular Diaphragm Dielectric Elastomer Generators

Inflated Circular Diaphragm Dielectric Elastomer Generators (CD-DEGs) are a special embodiment of polymeric transducer that can be used to convert pneumatic energy into high-voltage direct-current electricity. Potential application of CD-DEGs is as power take-off system for wave energy converters that are based on the oscillating water column principle. Optimal usage of CD-DEGs requires the adequate knowledge of their dynamic electro-mechanical response. This paper presents a test-rig for the experimental study of the dynamic response of CD-DEGs under different programmable electro-mechanical loading conditions. Experimental results acquired on the test-rig are also presented, which highlight the dynamic performances of CD-DEGs that are based on acrylic elastomer membranes and carbon conductive grease electrodes

A new class of variable capacitance generators based on the dielectric fluid transducer

This paper introduces the novel concept of dielectric fluid transducer (DFT), which is an electrostatic variable capacitance transducer made by compliant electrodes, solid dielectrics and a dielectric fluid with variable volume and/or shape. The DFT can be employed in actuator mode and generator mode. In this work, DFTs are studied as electromechanical generators able to convert oscillating mechanical energy into direct current electricity. Beside illustrating the working principle of dielectric fluid generators (DFGs), we introduce different architectural implementations and provide considerations on limitations and best practices for their design. Additionally, the proposed concept is demonstrated in a preliminary experimental test campaign conducted on a first DFG prototype. During experimental tests a maximum energy per cycle of and maximum power of has been converted, with a conversion efficiency up to 30%. These figures correspond to converted energy densities of with respect to the displaced dielectric fluid and with respect to the mass of the solid dielectric. This promising performance can be largely improved through the optimization of device topology and dimensions, as well as by the adoption of more performing conductive and dielectric materials

Benign TdT-positive cells in pediatric and adult lymph nodes: a potential diagnostic pitfall

Benign TdT-positive cells have been documented in a variety of non-hematopoietic tissues. Scant data are however available on their presence in non-neoplastic lymph nodes. This study is aimed to: (i) characterize the presence/distribution of benign TdT-positive cells in pediatric and adult reactive lymph nodes; (ii) define the phenotype and nature of such elements. This retrospective study considered 141 reactive lymph nodes from pediatric and adult patients without history of neoplastic disease. TdT-positive cells were characterized by immunohistochemical and morphometric analyses and their presence was correlated with the clinical-pathological features. The nature of TdT-positive cells was investigated by: (i) double immunostaining for early lymphoid cell markers; and (ii) assessment of TdT expression in fetal lymph nodes. Sparse TdT-positive cells were documented in all pediatric cases and in most (76%) adult lymph nodes. TdT-positive cell density was higher in children than adults (15.9/mm2 versus 8.6/mm2; P<.05). TdT positivity did not correlate with any clinical and histological parameter and double immunostaining disclosed a phenotype compatible with early lymphoid precursors (positivity for CD34, CD10 and variable expression of CD7). A very high TdT-positive cell density (802.4/mm2) was reported in all fetal lymph nodes. In conclusion, TdT-positive cells are a common finding in pediatric and adult lymph nodes. The interstitial distribution and low number of such cells allows for the differential diagnosis with precursor lymphoid neoplasms. The high density in fetal lymph nodes and the phenotype of such cells suggest their belonging to an immature lymphoid subset gradually decreasing with age

Simplified HPLC-UV method for the determination of α-tocopherol in plasma

Vitamin E, known for its great nutritional importance, is normally included in animal diets as DL-α-tocopherol acetate.The authors propose a method that makes it possible to determine the concentration of vitamin E in plasma withoutsaponification. This method enable to avoid aggressive treatments on the analyte and complex procedures; it detectsvitamin E only in form of DL-α-tocopherol.Lipoproteins of analysed plasma were denaturised by methanol. Vitamin E was extracted by petroleum ether in presenceof NaCl. The extract was dried by rotavapor at 45 °C, solubilized by methanol and injected in HPLC (C18 column, reversedphase). The quantitative determination was carried out by UV detector settled on 294 nm.Tests of repeatability inter-analysis and intra-analysis gave coefficient of variability (CV%) respectively of 1.64 and2.41%. The mean recovery was 100%

Multiple or metastatic clear cell chondrosarcoma: a case report

We report multiple synchronous clear-cell chondrosarcomas in a 43-year-old patient. The patient had a lesion in the right proximal humerus and in the left femoral condyle. Bone scintigraphy revealed increased uptake in both foci. Pathological analysis confirmed the diagnosis in both locations. In the proximal humerus, wide resection of the tumour was performed with allograft reconstruction of the joint with osteosynthesis. The femoral condyle was treated with curettage, phenolization, and cementation. Over a follow-up of 10 years no recurrence or metastasis was observed

Extension of analytical indicial aerodynamics to generic trapezoidal wings in subsonic flow

Analytical indicial aerodynamic functions are calculated for several trapezoidal wings in subsonic flow, with a Mach number 0.3≤ Ma≤ 0.7. The formulation herein proposed extends well-known aerodynamic theories, which are limited to thin aerofoils in incompressible flow, to generic trapezoidal wing planforms. Firstly, a thorough study is executed to assess the accuracy and limitation of analytical predictions, using unsteady results from two state-of-the-art computational fluid dynamics solvers as cross-validated benchmarks. Indicial functions are calculated for a step change in the angle of attack and for a sharp-edge gust, each for four wing configurations and three Mach numbers. Then, analytical and computational indicial responses are used to predict dynamic derivatives and the maximum lift coefficient following an encounter with a one-minus-cosine gust. It is found that the analytical results are in excellent agreement with the computational results for all test cases. In particular, the deviation of the analytical results from the computational results is within the scatter or uncertainty in the data arising from using two computational fluid dynamics solvers. This indicates the usefulness of the developed analytical theories

Brain angioarchitecture and intussusceptive microvascular growth in a murine model of Krabbe disease

Abstract Defects of the angiogenic process occur in the brain of twitcher mouse, an authentic model of human Krabbe disease caused by genetic deficiency of lysosomal b-galactosylceramidase (GALC), leading to lethal neurological dysfunctions and accumulation of neurotoxic psychosine in the central nervous system. Here, quantitative computational analysis was used to explore the alterations of brain angioarchitecture in twitcher mice. To this aim, customized ImageJ routines were used to assess calibers, amounts, lengths and spatial dispersion of CD31? vessels in 3D volumes from the postnatal frontal cortex of twitcher animals. The results showed a decrease in CD31 immunoreactivity in twitcher brain with a marked reduction in total vessel lengths coupled with increased vessel fragmentation. No significant changes were instead observed for the spatial dispersion of brain vessels throughout volumes or in vascular calibers. Notably, no CD31? vessel changes were detected in twitcher kidneys in which psychosine accumulates at very low levels, thus confirming the specificity of the effect. Microvascular corrosion casting followed by scanning electron microscopy morphometry confirmed the presence of significant alterations of the functional angioarchitecture of the brain cortex of twitcher mice with reduction in microvascular density, vascular branch remodeling and intussusceptive angiogenesis. Intussusceptive microvascular growth, con- firmed by histological analysis, was paralleled by alterations of the expression of intussusception-related genes in twitcher brain. Our data support the hypothesis that a marked decrease in vascular development concurs to the onset of neuropathological lesions in twitcher brain and suggest that neuroinflammation-driven intussusceptive responses may represent an attempt to compensate impaired sprouting angiogenesis

Current Evidence Supporting the Role of Immune Response in ATTRv Amyloidosis

Hereditary transthyretin (ATTRv) amyloidosis with polyneuropathy, also known as familial amyloid polyneuropathy (FAP), represents a progressive, heterogeneous, severe, and multisystemic disease caused by pathogenic variants in the TTR gene. This autosomal-dominant neurogenetic disorder has an adult onset with variable penetrance and an inconstant phenotype, even among subjects carrying the same mutation. Historically, ATTRv amyloidosis has been viewed as a non-inflammatory disease, mainly due to the absence of any mononuclear cell infiltration in ex vivo tissues; nevertheless, a role of inflammation in its pathogenesis has been recently highlighted. The immune response may be involved in the development and progression of the disease. Fibrillary TTR species bind to the receptor for advanced glycation end products (RAGE), probably activating the nuclear factor κB (NF-κB) pathway. Moreover, peripheral blood levels of several cytokines, including interferon (IFN)-gamma, IFN-alpha, IL-6, IL-7, and IL-33, are altered in the course of the disease. This review summarizes the current evidence supporting the role of the immune response in ATTRv amyloidosis, from the pathological mechanisms to the possible therapeutic implications