On the performance of advanced integrated microring filters for switching applications in next-generation elastic optical networks

We investigate the use of integrated advanced microring resonator-based sum-difference all-pass optical filters for switching applications in circuit-switched elastic optical networks. A practical design taking into account optical losses accordingly to typical reported values for strip waveguides in silicon-on-insulator technology is considered. By incorporating tuning elements (i.e., standard phase shifters), three different synthetized elliptic filters are emulated in the same physical structure showing the potential in terms of bandwidth configurability of the architecture. Practical filter design rules for standard silicon-on-insulator single-mode strip waveguides are also discussed. Beside possible advantages in terms of reduced fabrication costs, simulations performed on Nyquist PM-QPSK signals with different channel capacities over 50, 37.5 and 25 GHz frequency slots suggest that the proposed structure can achieve similar or better performance than commercial spectrum selective switch filters.     

Expanding the Potential of G‐Quadruplex Structures: Formation of a Heterochiral TBA Analogue

In order to expand the potential applications of G‐quadruplex structures, we explored the ability of heterochiral oligodeoxynucleotides based on the thrombin‐binding aptamer (TBA) sequence to fold into similar complexes, with particular focus on their resistance in biological environments. A combination of CD and NMR techniques was used. Similarly to TBA, the ODN ggTTggtgtggTTgg (lower case letters indicate L residues) is able to fold into a chair‐like antiparallel G‐quadruplex structure, but has a slightly higher thermal stability. The discovery that heterochiral ODNs are able to form stable G‐quadruplex structures opens up new possibilities for their development in several fields, as aptamers, sensors and, as recently shown, as catalysts for enantioselective reactions.     

Use of carbon dioxide as feedstock for chemicals and fuels: homogeneous and heterogeneous catalysis

CO₂ is considered to play a key role in an eventual climate change, due to its accumulation in the atmosphere. The control of its emission represents a challenging task that requires new ideas and new technologies. The use of perennial energy sources and renewable fuels instead of fossil fuels and the conversion of CO₂ into useful products are receiving increased attention. The utilization of CO₂ as a raw material for the synthesis of chemicals and fuels is an area in which scientists and industrialists are much involved: the implementation of such technology on a large scale would allow a change from a linear use of fossil carbon to its cyclic use, mimicking Nature. In this paper the use of CO₂ as building block is discussed. CO₂ can replace toxic species such as phosgene in low energy processes, or can be used as source of carbon for the synthesis of energy products. The reactions with dihydrogen, alcohols, epoxides, amines, olefins, dienes, and other unsaturated hydrocarbons are discussed, under various reaction conditions, using metal systems or enzymes as catalysts. The formation of products such as formic acid and its esters, formamides, methanol, dimethyl carbonate, alkylene carbonates, carbamic acid esters, lactones, carboxylic acids, and polycarbonates, is described . The factors that have limited so far the conversion of large volumes of CO₂ are analyzed and options for large‐scale CO₂ catalytic conversion into chemicals and fuels are discussed. Both homogeneous and heterogeneous catalysts are considered and the pros and cons of their use highlighted. © 2013 Society of Chemical Industry     

Behaviour of cod liver oil during the autoxidation process

Prostaglandin‐like compounds, called isoprostanes, are generated by free enzyme‐independent radical peroxidation of the acids arachidonic (AA), eicosapentaenoic (EPA) and docosahexaenoic (DHA). Up to now, isoprostanes have been largely studied only in men and biological systems, but never in food. In this research, cod liver oil was used as a model system to study the oxidation mechanism in food containing high amounts of EPA and DHA. For comparison, under similar oxidation conditions, also the behaviour of a sunflower seed oil and an n‐3 long‐chain polyunsaturated fatty acid capsule supplement oil were studied. It was ascertained that EPA‐ and DHA‐derived compounds were formed during oxidation. These compounds were polar and easily isolatable by methanol from oxidised transmethylated oil. EPA and DHA oxidation derivatives showed maximal absorbance at 200 nm and were very potent pro‐oxidants at high temperatures. In oxidised sunflower oil, similar compounds did not form. Unfortunately, the chemical structures of the EPA and DHA oxidation derivatives were not discovered, but it is a realistic hypothesis that they could be isoprostane‐like compounds.     

Layer-by-layer deposition of shortened nanotubes or polyethylene glycol-derivatized nanotubes on liposomes: A tool for increasing liposome stability

A simple strategy for preparing potential drug delivery systems is presented which appears to be a good alternative to stealth liposomes in terms of stability in buffered aqueous solutions. Microcapsules have been prepared by deposition of shortened and polyethylene glycol-derivatized nanotubes onto positively charged multilamellar vesicles using the layer-by-layer technique. The stability of microcapsules has been determined turbidimetrically by measuring the rate of microcapsule breakdown induced by addition of a destabilizing agent such as the nonionic surfactant octaethyleneglycol mono-n-dodecyl ether. The investigated microcapsules have proven to be more stable than both pure liposomes and stealth liposomes.     

Effect of Chain-Length and Countersurface on the Tribochemistry of Bulk Zinc Polyphosphate Glasses

Zinc polyphosphate glasses are considered to be chiefly responsible for the anti-wear efficiency of ZnDTP tribofilms. In this work, the tribochemical properties of amorphous bulk zinc polyphosphates of different chain lengths (ranging from zinc metaphosphate to zinc pyrophosphate) have been investigated. Tribological tests on bulk polyphosphate discs have been carried out using steel and quartz balls as counter-surfaces in a poly-??-olefin (PAO) bath at room temperature. The composition in the wear track and on the contact region of the balls has been monitored by small-area and imaging X-ray photoelectron spectroscopy (i-XPS). The XPS analysis revealed that the composition of short-chain-length polyphosphates remained unchanged following tribological stress. Long-chain-length polyphosphates are depolymerized in the wear track as a consequence of a tribochemical reaction. By comparing the results obtained using quartz and steel balls, it could be observed that while the reaction of iron oxide with the polyphosphates certainly plays a role in the depolymerization of the samples under sliding conditions, pressure and shear stress alone and also in the presence of water or oil-oxidized species are able to depolymerize the glass when an inert material is used as counterpart; the composition of the wear track, in this case, is dependent on the applied load. All samples were able to form an adhesive, glassy transfer film on both steel and quartz balls, but the short-chain-length polyphosphates showed a lower friction coefficient and wear coefficient. The results suggest a third-body mechanism with the polyphosphates acting as a solid lubricant. Differences in tribological behavior of the different-chain-length polyphosphates are attributable to their mechanical and rheological properties.     

Mass spectrometry-based tear proteomics for noninvasive biomarker discovery

The lacrimal film has attracted increasing interest in the last decades as a potential source of biomarkers of physiopathological states, due to its accessibility, moderate complexity, and responsiveness to ocular and systemic diseases. High-performance liquid chromatography-mass spectrometry (LC-MS) has led to effective approaches to tear proteomics, despite the intrinsic limitations in sample amounts. This review focuses on the recent progress in strategy and technology, with an emphasis on the potential for personalized medicine. After an introduction on lacrimal-film composition, examples of applications to biomarker discovery are discussed, comparing approaches based on pooled-sample and single-tear analysis. Then, the most critical steps of the experimental pipeline, that is, tear collection, sample fractionation, and LC-MS implementation, are discussed with reference to proteome-coverage optimization. Advantages and challenges of the alternative procedures are highlighted. Despite the still limited number of studies, tear quantitative proteomics, including single-tear investigation, could offer unique contributions to the identification of low-invasiveness, sustained-accessibility biomarkers, and to the development of personalized approaches to therapy and diagnosis.     

Microsomal lipid peroxidation: Effect of vitamin E and its functional interaction with phospholipid hydroperoxide glutathione peroxidase

The role of vitamin E in the protection against iron dependent lipid peroxidation was studied in rat liver microsomes and Triton-dispersed microsomal lipid micelles. In these systems, an antioxidant effect of vitamin E at a physiological ratio to phospholipids could be observed only in the presence of phospholipid hydroperoxide glutathione peroxidase (PHGPX) and glutathione. The rationale of this cooperation is discussed on the basis of the hydroperoxyl radical scavenging capacity of vitamin E and the reduction of membrane hydroperoxides by PHGPX. The scavenging of lipid hydroperoxyl radicals by vitamin E, although inhibiting propagation of the peroxidative chain, produces lipid hydroperoxides from which ferrous iron generates alkoxyl radicals that react with vitamin E almost as fast as with fatty acids. Therefore, only if membrane hydroperoxides are continuously reduced by this specific peroxidase does the scavenging of hydroperoxyl radicals by vitamin E lead to an effective inhibition of lipid peroxidation.     

Structural Features of the ATP-Binding Cassette (ABC) Transporter ABCA3

In this review we reported and discussed the structural features of the ATP-Binding Cassette (ABC) transporter ABCA3 and how the use of bioinformatics tools could help researchers to obtain a reliable structural model of this important transporter. In fact, a model of ABCA3 is still lacking and no crystallographic structures (of the transporter or of its orthologues) are available. With the advent of next generation sequencing, many disease-causing mutations have been discovered and many more will be found in the future. In the last few years, ABCA3 mutations have been reported to have important pediatric implications. Thus, clinicians need a reliable structure to locate relevant mutations of this transporter and make genotype/phenotype correlations of patients affected by ABCA3-related diseases. In conclusion, we strongly believe that the model preliminarily generated by these novel bioinformatics tools could be the starting point to obtain more refined models of the ABCA3 transporter.     

Molecular Classification and Pharmacogenetics of Primary Plasma Cell Leukemia: An Initial Approach toward Precision Medicine

Primary plasma cell leukemia (pPCL) is a rare and aggressive variant of multiple myeloma (MM) which may represent a valid model for high-risk MM. This disease is associated with a very poor prognosis, and unfortunately, it has not significantly improved during the last three decades. New high-throughput technologies have allowed a better understanding of the molecular basis of this disease and moved toward risk stratification, providing insights for targeted therapy studies. This knowledge, added to the pharmacogenetic profile of new and old agents in the analysis of efficacy and safety, could contribute to help clinical decisions move toward a precision medicine and a better clinical outcome for these patients. In this review, we describe the available literature concerning the genomic characterization and pharmacogenetics of plasma cell leukemia (PCL).