High-temperature elastic moduli of thermoelectric SnTe1±x – y SiC nanoparticulate composites

In waste heat recovery applications, thermoelectric (TE) generators are subjected to thermal gradients and thermal transients, creating mechanical stresses in the TE legs. Such stresses are functions of the elastic moduli of the TE material. For SnTe_1±x matrices (where x = 0.0 or 0.016) composite specimens with 0–4 vol% SiC nanoparticle (SiC_NP) additions, the elastic moduli (Young’s modulus, shear modulus, and Poisson’s ratio) were measured by resonant ultrasound spectroscopy from room temperature (RT) to 663 K. The effects of matrix composition and the SiC_NP additions on the RT intercepts and the slopes of the elastic modulus as a function of temperature are also discussed.     

The thermal expansion coefficient as a key design parameter for thermoelectric materials and its relationship to processing-dependent bloating

The coefficient of thermal expansion (CTE) is a key design parameter for thermoelectric (TE) materials, especially in energy harvesting applications since stresses generated by CTE mismatch, thermal gradients, and thermal transients scale with the CTE of the TE material. For the PbTe–PbS-based TE material (Pb_0.95Sn_0.05Te)_0.92(PbS)_0.08—0.055 % PbI₂ over the temperature ranges of 293–543 and 293–773 K, a CTE, α_avg, of 21.4 ± 0.3 × 10^?6 K^?1 was measured using (1) dilatometry and (2) high-temperature X-ray diffraction (HT-XRD) for powder and bulk specimens. The CTE values measured via dilatometry and HT-XRD are similar to the literature values for other Pb-based chalcogenides. However, the processing technique was found to impact the thermal expansion such that bloating (which leads to a hysteresis in thermal expansion) occurred for hot pressed billets heated to temperatures >603 K while specimens fabricated by pulsed electric current sintering and as-cast specimens did not show a bloating-modified thermal expansion even for temperatures up to 663 K. The relationship of bloating to the processing techniques is discussed, along with a possible mechanism for inhibiting bloating in powder processed specimens.     

Lean,Six Sigma and Lean Six Sigma: an analysis based on operations strategy

There is a growing need for operations management models that contribute to the continuous improvement of company processes, among them we highlight lean manufacturing, Six Sigma and, more recently, Lean Six Sigma (LSS). This article aims (1) to identify and analyse the differences and complementarities in the production decision areas for each one of the three models; (2) to identify the competitive priorities that lead to the best performance as a result of policies followed in the decision areas as a result of the adopted model. First, a theoretical conceptual model was developed based on a review of the literature, followed by a exploratory research questions applied to manufacturing companies that use the lean, Six Sigma or LSS manufacturing models in southern Brazil. The main results show that there are differences in the models in relation to the importance of the decision areas and the performance achieved in the competitive priorities. Individually, lean manufacturing, Six Sigma and LSS have varying degrees of importance in the Facilities, Vertical Integration and Production Planning and Control decision areas. The performance dimensions with the best performance are speed, quality, reliability and cost.     

Implementing a non-local xor function with quantum communication

The or-exclusive function (xor) is one of the most important logical functions, and can be used in several protocols and algorithms, as encryption and error correction. This paper discusses several ways to implement the xor function, in a secure way using quantum communication, between users of a network. It is shown how to implement it using bipartite, tripartite and four-partite maximally entangled states, as well using an optical interferometer and strongly attenuated coherent states. Some protocols for secure communication using the xor, as quantum key distribution, are also proposed.     

Synthesis of silver nanoparticles using reducing agents obtained from natural sources (Rumex hymenosepalus extracts)

We have synthesized silver nanoparticles from silver nitrate solutions using extracts of Rumex hymenosepalus, a plant widely found in a large region in North America, as reducing agent. This plant is known to be rich in antioxidant molecules which we use as reducing agents. Silver nanoparticles grow in a single-step method, at room temperature, and with no addition of external energy. The nanoparticles have been characterized by ultraviolet-visible spectroscopy and transmission electron microscopy, as a function of the ratio of silver ions to reducing agent molecules. The nanoparticle diameters are in the range of 2 to 40 nm. High-resolution transmission electron microscopy and fast Fourier transform analysis show that two kinds of crystal structures are obtained: face-centered cubic and hexagonal.     

Vascular Damage in Patients with Nonalcoholic Fatty Liver Disease: Possible Role of Iron and Ferritin

Non Alcoholic Fatty Liver Disease (NAFLD) is the most common chronic liver disease in Western countries. Recent data indicated that NAFLD is a risk factor by itself contributing to the development of cardiovascular disease independently of classical known risk factors. Hyperferritinemia and mild increased iron stores are frequently observed in patients with NAFLD and several mechanisms have been proposed to explain the role of iron, through oxidative stress and interaction with insulin metabolism, in the development of vascular damage. Moreover, iron depletion has been shown to decrease atherogenesis in experimental models and in humans. This review presents the recent evidence on epidemiology, pathogenesis, and the possible explanation of the role of iron and ferritin in the development of cardiovascular damage in patients with NAFLD, and discusses the possible interplay between metabolic disorders associated with NAFLD and iron in the development of cardiovascular disease.     

Ethanol exposure during peripubertal period increases the mast cell number and impairs meiotic and spermatic parameters in adult male rats

Puberty is characterized by psychosomatic alterations, whereas chronic ethanol consumption is associated with morphophysiological changes in the male reproductive system. The purpose of this study was to show the toxic effects on testis and epididymal morphophysiology after ethanol administration during peripuberty. To this end, male Wistar rats were divided into two groups: ethanol (E) group: received a 2 g dose of ethanol/kg in 25% (v/v); and control (C) group: received the same volume of filtered water; both were treated by gavage for 54 days. On the 55th day of the experiment, epididymis, and testis were collected for sperm count, histopathology, mast cell count, and morphometry. The vas deferens was collected for sperm motility analysis. The femur and testicle were used for cytogenetic analysis. Ethanol exposure caused reduction in daily sperm production (DSP) and in sperm motility, multinucleated cells or those having no chromosomal content, and late chromosome migrations. No changes were observed in the number of chromosomes in the mitotic analysis. However, some alterations could be seen in meiocytes at different stages of cell division. Stereological analysis of the epididymis indicated reorganization of its component in the 2A and 5A/B regions. The epididymal cauda had greater recruitment, and both degranulated and full mast cells showed an increase in the initial segment, in the ethanol group. In conclusion, ethanol administration during the pubertal phase affects epididymis and testis in adult rats, as indicated mainly by our new findings related to mast cell number and meiotic impact. Microsc. Res. Tech. 79:541–549, 2016. © 2016 Wiley Periodicals, Inc.     

Modulation of proteasome machinery by natural and synthetic analogues of the marine bioactive compound petrosaspongiolide M

Natural or synthetic? Several petrosaspongiolide M natural and synthetic analogues have been tested as proteasome inhibitors and apoptosis modulators. The natural petrosaspongiolide M congeners gave a consistent decrease in activity. Among the synthetic analogues, the introduction of the benzothiophene ring resulted in a bioequivalent alternative of the petrosaspongiolide M terpenoid system.     

Non-destructive flavour evaluation of red onion (Allium cepa L.) Ecotypes: An electronic-nose-based approach

This work reports preliminary results on the potential of a metal oxide sensor (MOS)-based electronic nose, as a non-destructive method to discriminate three “Tropea Red Onion” PGI ecotypes (TrT, TrMC and TrA) from each other and the common red onion (RO), which is usually used to counterfeit. The signals from the sensor array were processed using a canonical discriminant function analysis (DFA) pattern recognition technique. The DFA on onion samples showed a clear separation among the four onion groups with an overall correct classification rate (CR) of 97.5%.