On context-aware co-clustering with metadata support

In traditional co-clustering, the only basis for the clustering task is a given relationship matrix, describing the strengths of the relationships between pairs of elements in the different domains. Relying on this single input matrix, co-clustering discovers relationships holding among groups of elements from the two input domains. In many real life applications, on the other hand, other background knowledge or metadata about one or more of the two input domain dimensions may be available and, if leveraged properly, such metadata might play a significant role in the effectiveness of the co-clustering process. How additional metadata affects co-clustering, however, depends on how the process is modified to be context-aware. In this paper, we propose, compare, and evaluate three alternative strategies (metadata-driven, metadata-constrained, and metadata-injected co-clustering) for embedding available contextual knowledge into the co-clustering process. Experimental results show that it is possible to leverage the available metadata in discovering contextually-relevant co-clusters, without significant overheads in terms of information theoretical co-cluster quality or execution cost.     

The influence of citrate and tartrate on the electrodeposition and surface morphology of Cu–Ni layers

This study examined the influence of citrate and tartrate as complexing agents on the electrodeposition and surface morphology of Cu–Ni layers. The alloys obtained in the tartaric acid and sulphate baths were nobler than those obtained in the citric acid/citrate and citric acid/citrate/tartaric acid media. The results indicated that the complexing medium influences the nobility and the type of mass transport of the alloy formed. The morphology of the electrodeposited Cu–Ni layers changed from a rather porous appearance in the absence of the complexing agents to nodular, cracked mud and cauliflower appearances for the citric acid/sodium citrate/sodium sulphate medium, tartaric acid/sodium sulphate medium and citric acid/sodium citrate/tartaric acid/sodium sulphate medium, respectively. The chemical composition of the Cu–Ni layers revealed the preferential deposition of copper. The ultraviolet–visible spectrophotometry measurements indicated the occurrence of the d–d type transition, regardless of the complexing medium employed.     

Effect of the structure of monoglyceride–oil–water gels on aroma partition

The aim of the present research was to study the aroma partition properties of saturated monoglyceride–oil–water gels. To this purpose, gels added with lemon oil were prepared mixing water, sunflower oil and commercial saturated monoglycerides. Three mixtures containing different ratios between the ingredients were considered. The gel characteristics were studied by synchrotron X-ray diffraction (XRD), calorimetry, polarized light microscopy and rheological measurements. The aroma partition was studied by using HSGC analysis.The gel structure is made of a multilamellar crystalline network, in which monoglycerides form shells encapsulating oil. Depending on the ratio between ingredients, the gel shows different rheological behaviour. The structured multilamellar phases greatly affect the partition of aroma evidencing the capability to entrap lipophilic compounds within the monoglyceride/oil shells. Since the aroma entrapping capacity showed by monoglyceride structures could greatly affect the perceived aroma intensity of the final product, this effect should be carefully taken into account during the development of new formulations.     

Secondhand smoke exposure in Mexican discotheques.

This study describes the impact of exposure to secondhand smoke for subjects who spend time in a discotheque, by comparing within-subject baseline and postexposure urinary cotinine levels. A total of 100 nonsmoking volunteers from a central region of Mexico provided a urine sample before entering a discotheque and another sample an average of 6 hr after the end of exposure. Concentrations of cotinine and its metabolite, trans-3'-hydroxycotinine, were measured in the urine by liquid chromatography-mass spectrometry. In females the average preexposure level of urinary cotinine was 2.2 ng/ml, and the average postexposure level was significantly higher, at 15.7 ng/ml. In males the average preexposure level of cotinine was 3.7 ng/ml, compared with 49.1 ng/ml in the postexposure assessment. The highest postexposure values were found in men younger than 22 years old with a value of 469.5 ng/ml. Exposure to secondhand smoke is a serious health risk. Our findings are important given that many of our subjects were exposed to substantial amounts of secondhand smoke in discotheques, as evidenced by the high urinary cotinine and 3'-hydroxycotinine concentrations. These findings support the need to prohibit smoking in discotheques to protect nonsmokers' health.     

Potassium ion transport by gramicidin and valinomycin across a Ag(1 1 1)-supported tethered bilayer lipid membrane

A tethered bilayer lipid membrane (tBLM) was prepared by anchoring a thiolipid monolayer to a Ag(1 1 1) single crystal from a thiolipid solution in ethanol; a diphytanoylphosphatidylcholine monolayer was then self-assembled on top of the thiolipid monolayer from a lipid solution in hexane or ethanol. The thickness of the mixed thiolipid|lipid bilayer was estimated at 7.5 ± 0.5 nm by scratching holes in the tBLM with an AFM tip and determining their height profile and the frequency distribution of height. The effect of the incorporation of gramicidin A and valinomycin upon K⁺ ion transport across the tBLM was investigated by electrochemical impedance spectroscopy. The position of the inflection point of the sigmoidal curve of the in-phase component of the electrode admittance against potential allowed the determination of an approximate scale of the absolute potential difference across the whole Ag(1 1 1)|(aqueous solution) interface, on the basis of a model of the electrified interface.     

Comparison of UF synthesis by alkaline‐acid and strongly acid processes

This work discusses two processes for producing urea‐formaldehyde (UF) resins. One is the alkaline‐acid process, which has three steps: usually an alkaline methylolation followed by an acid condensation and finally the addition of a final amount of urea. The other process, the strongly acid process, consists of four steps, in which the first step involves a strongly acid condensation followed by an alkaline methylolation, a second condensation under a moderately acid pH and finally, methylolation and neutralization under a slight alkaline pH. Two resins were produced using the two above described processes. The molecular weight distribution (MWD) of the resins was monitored off‐line by GPC/SEC and the final resins were characterized by GPC/SEC and HPLC. These studies showed that the two resins differ greatly in chemical structure, composition, viscosity, and reactivity. The monitoring of MWD indicated that the first condensation under a strongly acid environment leads to the production of a polymer with a distinctly different chemical structure, therefore increasing the flexibility of polymer synthesis and opening the way to the improvement of end‐use properties. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

High performance sulfonated aromatic ionomers by solvothermal macromolecular synthesis

Thermal cross-linking in presence of residual solvent dimethylsulfoxide without any addition of cross-linker molecules is described. This elegant method increases spectacularly the mechanical and hydrolytic stability of sulfonated aromatic polymers (SAP), making them suitable for use in liquid water also at 145 °C. Data on water uptake, mechanical properties and proton conductivity are presented and discussed from a bond energy point of view. The developed method is also inexpensive, being incorporated in the normal membrane casting procedure. This opens new horizons and hitherto conventionally disregarded SAP membranes should be reconsidered as fuel cell membranes.     

Synthesis,characterization and photovoltaic properties of a new thiophene-based double-cable polymer with pendent fullerene group

In this paper we report the synthesis of a new thiophenic 3-substituted monomer with a plastifying side chain bearing a C₆₀-fullerene moiety at the end. The monomer has been copolymerized with 3-hexylthiophene through the simplest chemical method, namely oxidative polymerization with iron trichloride. The final copolymer, with a high fullerene content (1:1 wt/wt), was fully soluble in common organic solvents and its solubility allowed for its complete physic-chemical characterization. The copolymer thermal behavior was investigated by TGA analysis showing that the incorporation of fullerene has beneficial effects on thermal stability. The fluorescence spectroscopy showed a strong quenching of fluorescence of the copolymer main chains in film, while the AFM analysis confirmed the homogeneous morphology of its films with only very small and uniformly distributed aggregates. The photovoltaic performances of the copolymer and of a film obtained by blending the prepared monomer with poly(3-hexylthiophene) were significantly higher than those obtained using conventional materials and architectures.