Averaged strain energy density and J-integral for U- and blunt V-shaped notches under torsion

Analytical solutions for the J-integral and the strain energy density (SED) averaged over a control volume are presented for U- and blunt V-shaped notches under torsion. The influence of the notch tip radius and the notch opening angle are fully included in the new proposed relationships. These expressions take advantage of some recent solutions for the stress fields ahead of blunt notches under Mode III loading and can be seen as a synthesis of the efforts carried out during the last years by the present authors on this topic. Afterwards, the expressions are applied to a recent set of experimental data from cracked, notched and plain specimens tested under torsion at low temperature \((-60\,^{\circ }\hbox {C})\) . The large scatter shown by notched specimens in terms of maximum elastic stresses strongly reduces when the J-integral or the local SED are used in combination with the specific control volumes.     

Carbon Nanostructures for Nanomedicine: Opportunities and Challenges

Carbon nanostructures (e.g., fullerenes, CNTs, graphene, nanohorns, nanodiamonds) play a key role in the development of nanomedicines. Here we analyze opportunities and barriers for their application in clinical settings. In particular, we discuss the unique properties of certain carbon nanostructures that allow for innovative solutions in theranostics, as well as current pitfalls around clinical applications of the EPR effect, the formation of the protein corona, and how functionalization of CNTs is a key tool to modulate their biodistribution and toxicity.     

Luminescent solar concentrators employing new Eu(TTA)3phen‐containing parylene films

New robust luminescent solar concentrators were produced by growing Eu(TTA)₃phen‐containing parylene thin films on poly(methyl methacrylate) slabs through a novel co‐deposition process. As it is the first time that Eu(TTA)₃phen molecules were inserted in parylene matrix, the deposition process was investigated, and the features of the samples were extensively analyzed. Fourier transform infrared spectroscopy analysis demonstrated the integrity of the vacuum‐sublimated Eu(TTA)₃phen molecules. Atomic force microscope analysis showed the very flat surface of the films (Rq = 3.7 nm), which is strategic in luminescent solar concentrators (LSCs) for minimizing the light scattering at the air/film interface. The optical measurements demonstrated that Eu(TTA)₃phen‐containing parylene exhibits higher absorption than the conventional Eu(TTA)₃phen films and the luminescence peaks characteristic of Eu(TTA)₃phen compound. This indicates that the Eu complex is not affected by the matrix interaction thus maintaining its extremely large Stokes shift. Moreover, the parylene matrix improves the luminescence intensity of the films: in fact, under the same absorption, these films show a luminescence intensity more than two times higher than standard Eu(TTA)₃phen ones. The current–voltage (I–V) measurements show that, under the same quantity of Eu(TTA)₃phen, Eu(TTA)₃phen‐containing parylene LSCs produce a current density more than twice as high as LSC without parylene and that their efficiency decreases more than ten times slower than organic‐based LSCs at increasing illuminating area, thus highlighting the feasibility of developing large size LSCs. Copyright © 2014 John Wiley & Sons, Ltd.     

An Unbalanced Synaptic Transmission: Cause or Consequence of the Amyloid Oligomers Neurotoxicity?

Amyloid-β (Aβ) 1-40 and 1-42 peptides are key mediators of synaptic and cognitive dysfunction in Alzheimer’s disease (AD). Whereas in AD, Aβ is found to act as a pro-epileptogenic factor even before plaque formation, amyloid pathology has been detected among patients with epilepsy with increased risk of developing AD. Among Aβ aggregated species, soluble oligomers are suggested to be responsible for most of Aβ’s toxic effects. Aβ oligomers exert extracellular and intracellular toxicity through different mechanisms, including interaction with membrane receptors and the formation of ion-permeable channels in cellular membranes. These damages, linked to an unbalance between excitatory and inhibitory neurotransmission, often result in neuronal hyperexcitability and neural circuit dysfunction, which in turn increase Aβ deposition and facilitate neurodegeneration, resulting in an Aβ-driven vicious loop. In this review, we summarize the most representative literature on the effects that oligomeric Aβ induces on synaptic dysfunction and network disorganization.     

Characterization of boron doped diamond during oxidation processes: Relationship between electronic structure and electrochemical activity

This work investigates the behaviour of BDD samples differently aged by an oxidative treatment. Two series of data are presented: the first in acid solutions was used to derive information about the electronic structure of the samples, whereas measurements in equimolar ferro/ferri cyanide solutions were performed to test the activity of the samples towards charge transfer reaction. Flat band potential as well as energy levels of conduction and valence bands were calculated for new and aged samples. These parameters, together with the current voltage response, are crucial information for a comprehensive interpretation of the behaviour of samples.     

Effect of processing stages of apple juice concentrate on patulin levels

The effects of different stages of apple juice concentrate production on patulin levels were investigated. Patulin was detected in all samples analyzed in concentrations ranging from 56 to 653 μg/L. Apple paste resulted from milling process had high levels of patulin. The results of this study indicate that it is possible to reduce patulin level in apple juices. After pasteurization, enzymatic treatment, microfiltration and evaporation processes, the mean loss of patulin was 39.6, 28.3, 20.1 and 28.4%, respectively. When apple juices concentrate were diluted from 69 to 12°Brix to consume, patulin content ranged from 15 to 46 μg/L. Patulin content in all juice samples was lower than the limit of 50 μg/L considered acceptable by the Codex Alimentarius Commission. But if consider the maximum permitted concentration established for apple products intended for infants and young children by The Commission of the European Communities all samples were found to exceed patulin concentration of 10 μg/L.     

Un linguaggio simbolico di simulazione: Il siford

Simulation has proved to be a powerful tool for research in all problems for which satisfactory analitical techniques are not available. It is well known, for instance, the considerable difficulty of the analytical approach to systems containing a certain number of stochastic variables which interact reciprocally. It is also known that in the intensive use of digital simulation (Monte Carlo Method) the long time required for the compilation and the debugging of the corresponding programmes arises as a principal obstacle to efficient solution. The SIFOR language was created to bypass the above mentioned difficulties. By means of the SIFOR language one has but to describe the system in question through a block diagram (SIFOR blocks). On the bases of such a scheme the SIFOR compiler the supplies requested simulation programme. The aim of this paper is to describe the SIFOR blocks which are to be employed in the programme-write up. Some of the SIFOR blocks «generate» flows of transactions, other ones define the lows with which the transactions «go through» the system, and finally other blocks «absolve» the transactions when the latter have completed their course. During the simulated passage of the transactions through the system the programme holds all the informations which, after appropriate handling, represent the final, results of the simulation.     

采用中间电压总线架构的分布式电源转换

今天,电信、汽车与工业应用对复杂电源系统要求更高的功率效率、多个低电压供电通道,同时更有限的容差和高级顺序上电功能。例如,通信系统的开发者不断在相同尺寸的电路板上装入更多元器件,使其具备更高的性能。电源系统必须供应很低的输出电压与大电流,才能满足高性能通信系统芯片的电源需求。美国国家半导体最近推出一款电源转换系列集成电路(IC),用于中间电源总线的新型控制器,使得用于分布式电源架构的先进隔离直流/直流控制器系列更臻完善,可满足下一代通信系统的电源需求。LM5000系列可耐受高达100V的瞬变电压,比现有解决方案的效率…