Thermal Conductivity of Infrared Transparent Chalcogenide Glasses

Chalcogenide glasses exhibit low thermal conductivities on the order of 10^-3 W cm^-1K^-1. Since many of these glasses are transparent in the infrared, the photon contribution to the apparent thermal conductivity of these materials can be significant even at relatively low temperatures, The temperature-dependent thermal conductivity of Ge₂₈ Sb₁₂ Se₆₀ was measured over the range 175 to 475 K and a simplified approach is presented to correct the data for radiation (photon) effects. In addition, room-temperature thermal conductivities of 13 other glass compositions were measured. The phonon conductivities agreed well with simple Debye theory predictions after the radiation contributions were eliminated.     

High passage numbers induce resistance to apoptosis in C2C12 muscle cells

Cell lines with high passage numbers exhibit alterations in cell morphology and functions. In the present work, C2C12 skeletal muscle cells with either low (<20) or high (>60) passage numbers (identified as lC2C12 or h-C2C12, respectively) were used to investigate the apoptotic response to H2 O2 as a function of culture age h-C2C12. We found that older cultures (h-C2C12 group) were depleted of mitochondrial DNA (mtDNA). When we analyzed the behavior of Bad, Bax, caspase-3 and mitochondrial transmembrane potential, we observed that cells in the h-C2C12 group were resistant to H2 O2 induction of apoptosis. We propose serially cultured C2C12 cells as a refractory model to H2 O2 -induced apoptosis. In addition, the data obtained in this work suggest that mtDNA is required for apoptotic cell death in skeletal muscle C2C12 cells.     

Catalysis of Lipid Oxidation by Iron from an Insoluble Fraction of Beef Diaphragm Muscle

An insoluble fraction of beef diaphragm muscle was found to catalyze lipid oxidation in the presence of reducing compounds. Ascorbate (100 μM) catalyzed the formation of thiobarbituric acid reactive substances 3.3, 8.3 and 7.3-fold more effectively than cysteine, superoxide and NADPH, respectively. Ascorbate/insoluble fraction-catalyzed lipid oxidation was inhibited bv EDTA, ceruloolasmin, catalase and superoxide dismutase indicating the iivolvemknt of iron, hydrogen peroxide and superoxide anion. Both lipid oxidation and the release of iron from the insoluble fraction increased with increasing pH (5.0–7.0) in the presence of ascorbate. Iron bound to the insoluble components of beef muscle could be involved in catalysis of lipid oxidation.     

ANTIOXBDANT PROPERTIES OF OREGANO (ORIGANUM VULGARE) LEAF EXTRACTS

We tested the antioxidant properties of both aqueous and methanolic extracts of oregano (origanum vulgare) They proved to be effective in the inhibition of all phases of the peroxidative process: first neutralizing free radicals (superoxide anion, hydroxyl radical and 1,1‐diphenyl‐2‐picrylhydrazyl radical), then blocking peroxidation catalysis by iron (through iron‐chelating and iron‐oxidizing properties), and finally through interruption of lipid‐radical chain reactions (chain‐breaking activity). Their anti‐glycosylation activity was also effective. The glycosylation oflipoproteins is directly related to their peroxidation. The amount of extract used in our experiments was obtained from 0.1–1 mg of dried leaves, amounts far less than those normally used in the Mediterranean diet.     

An approach to size effect in fatigue of metals using fractal theories

ABSTRACT As was experimentally observed by several authors, the fatigue strength of metallic materials decreases with increasing the specimen size. Such a decrease can be remarkable for very large structures like, for example, big cargo ships (some hundred meters long) transporting oil or other goods. Size effect in fatigue is herein explained by considering the fractal nature of the reacting cross sections of structures, that is, the renormalized fatigue strength is represented by a force amplitude acting on a surface with a fractal dimension lower than 2, where such a dimensional decrement depends on a self‐similar weakening of the material ligament, owing to the presence of cracks, defects, voids and so forth (microscopic level). However, this decrement tends to progressively disappear with increasing the structure size (macroscopic level), i.e. the effect of the material microstructure on the macroscopic fatigue behaviour gradually vanishes for structures large enough with respect to a characteristic microstructural size, this phenomenon being defined as multifractality. A multifractal scaling law for fatigue limit of metals is proposed, and some experimental results are examined in order to show how to apply the theoretical approach presented.     

SARS-CoV-2 induced myocarditis: Current knowledge about its molecular and pathophysiological mechanisms

The existence of an inflammatory process in the heart muscle, related to a progressive worsening of myocardial function, different etiopathogenetic mechanisms concur and often overlap, thus making the diagnosis and the therapeutic approach complex. As the COVID-19 pandemic progresses, the effects of the disease on the organ systems and in particular on the cardiovascular system are becoming more and more profound. Cardiac involvement is a well-known event with a high percentage of findings in the heart’s magnetic field, even in asymptomatic areas. There are numerous uncertainties regarding their evolution, in the long and short term, due not only to a difficult to determine the varied clinical expression and the rarely performed intramyocardial biopsy which additionally presents diagnostic problems but also in part to different clinical prognosis. Today, the new SARS-CoV-2 virus that uses the angiotensin converting enzyme 2 (ACE2) which is present at high levels in myocardial cells as its entrance it can create even severe heart injury. The pathophysiology in all of these cases can involve multiple immune and non-immune mechanisms within organs and vessels and can be occur in the clinical phases. Possible mechanisms of direct and indirect myocardial infarction in patients with COVID-19 include additional lesion and oxygen-rich and generalized inflammation response with myocardial immune hyperactivity (myocarditis). Therefore, these can occur through the excessive release of cytokines, the presence of thrombocytopenia, endocrine damage, heart failure, arrhythmias and more. Patients can show average signs of myocardial damage, and some develop spontaneous cardiac complications, such as heart failure, arrhythmias and, rarely, rare cardiogenic disorders. Pathophysiology in all of these may involve multiple mechanisms within the cytokine cephalic membrane, endocrine damage and thrombogenicity. The diagnosis of this myocardial injuri is mainly based on the myocardial enzyme troponin. This viewpoint paper explains today’s knowledge on viral myocarditis, in particular that from SARS-CoV-2 infection, if there is a connection with other possible biomolecular pathogenetic factors that can influence its natural course. In fact, it is for this reason that the pathogenetic mechanisms are analyzed and described. At the same time, its possible interaction with other parameters that are documented risk factors for cardiovascular disease was examined. Although these biomolecular findings were mainly related to necrotic parts of the myocardium, it is important to recognize that myocardial damage early for a better approach and prognosis.     

CHEMICAL AND PHYSICAL ATTRIBUTES OF MUSKMELON RELATED TO TEXTURE

Effects were investigated of certain physical and chemical characteristics on muskmelon texture as described by sensory evaluation. Turgor pressure, moisture content and concentrations of total sugars, alcohol insoluble solids, three pectin fractions, starch and cellulose were determined in 50 melons purchased randomly from a retail market. Sensory assessments included crispness, fibrous-ness, and resistance to cutting, biting and crushing. Results indicated that the texture of muskmelon is determined largely by the type and amount of cell wall constituents. Maturity, inferred from starch and protopectin content, also affected sensory panel scores. Moisture, alcohol insoluble solids, total sugars and pectic substances, except protopectin, were not reliable texture indicators. Although turgor pressure was not related significantly to any textural characteristics, a trend was observed suggesting that this variable warrants further investigations.