Evaluation of thermal and high hydrostatic pressure processed apple purees enriched with prebiotic inclusions

The effects of high hydrostatic pressure (500 MPa/1.5 min/20 °C) and mild conventional pasteurization (P₉₀ > 10 min) processing on the fructan content, polyphenolic stability and physico-chemical characteristics of apple purees enriched with two commercial prebiotics [Beneo GR® (inulin) and HSI® (fructooligosaccharides—FOS)] over 30 days at 4 °C were evaluated. Fructan analysis showed that the prebiotics were stable throughout 30 days and were present in sufficient quantities to deliver a prebiotic effect. Fluctuations in physico-chemical characteristics were more evident in purees containing inulin than FOS. Sensory acceptability of purees was deemed acceptable (> 3) by panellists and showed no preference for either processing type. Minor deterioration in acceptability was observed in thermal processed samples containing inulin inclusions during storage (p < 0.05). Processing reduced (p < 0.05) the levels of some polyphenolic compounds in all samples compared to unprocessed controls, in particular chlorogenic acid and phloridzin, which were largely responsible for overall decreases in total phenolic index (TPI).

Industrial relevance

Studies have shown that high hydrostatic pressure processing (HHP) can better retain inherent functional components i.e. antioxidant compounds, compared to mild pasteurization. However, processors need to be assured that further additions of functionally beneficial components, such as prebiotics, are similarly protected. This study focussed primarily on assessing the effect of thermal and HHP on the stability of two prebiotics over storage (30 days at 4 °C). Results indicate that both prebiotics were stable and present in sufficient quantities to deliver a prebiotic effect for both processing types after storage. In some cases, less hydrolysis of the prebiotic occurred in HHP purees. These outcomes could help the food industry identify the optimal processing type to maximise retention of added and inherent functional properties.     

Fabrication and characterization of dye-sensitized solar cells from rutile nanofibers and nanorods

Rutile titania (TiO₂) nanofibers were prepared by electrospinning a polymeric sol containing a titanium precursor and Poly(vinylpyrrolidone) in acetic acid-ethanol mixture and subsequent sintering of the fibers at 800 °C. The resultant continuous, polycrystalline porous fibers contained TiO₂ grains of 15-20 nm sizes. The continuous fibers were broken down into nanorods by mechanical grinding. Morphology of the nanofibers and nanorods was characterized by scanning and transmission electron microscopies. The crystal structure and polycrystallinity of the fibers were further confirmed by X-ray diffraction analysis. Dye-sensitized solar cells (DSCs) fabricated from the nanofibers and rutile nanorods, respectively, showed superior performance with the later.     

Modulation of the superoxide anion production and MMP-9 expression in PMA stimulated THP-1 cells by olive oil minor components: Tyrosol and hydroxytyrosol

Extra virgin olive oil has been associated with a reduced incidence of risk factors for coronary heart disease also owing to the presence of antioxidant biophenols. Reactive oxygen species (ROS) and matrix metalloproteinase-9 (MMP-9) have been implicated in numerous somatic illnesses, including cardiovascular disorders and cancer. The aim of this work was to study the capacity of virgin olive oil tyrosol (T) and hydroxytyrosol (HT) at impairing superoxide production and MMP-9 expressions in monocyte cells (THP-1) conveniently differentiated into adherent macrophages, taken as a model of human macrophages implicated in atheroma.O₂⁻ production was evaluated in THP-1 cells by using lucigenin as a specific chemiluminescent probe. Cells, after differentiation for 72 h, were preincubated in the presence of HT and T at increasing concentrations for 4, 15 and 24 h, and then, monocyte-like cells were stimulated by phorbol myristate acetate (PMA) and the O₂⁻-dependent luminescence was immediately recorded at 37 °C by means of a Luminometer. Enzymatic activity of MMP-9 derived from a medium of cells preincubated, or not, with T or HT was tested by zymography.As compared to the cells without treatment, cells preincubated with HT, showed a decrease of O₂⁻ production (50%) at 1 ??M for 15 h of preincubation time. Tyrosol fully prevented ROS overproduction at 15 h and, like HT displayed a high degree of protection but at higher concentrations and later time points (24 h). Gelatin zymograms revealed a reduction of the expression of MMP-9 in conditioned medium derived from T and HT-treated cells. These findings give further evidence in favour of olive oil consumption to counteract cardiovascular diseases.     

Experimental thermodynamic cycles and performance analysis of a solar-powered adsorptive icemaker in hot humid climate

This paper analyzes and presents the thermodynamic cycles and the experimental performance parameters of a solar adsorptive icemaker that uses activated-carbon methanol pair. The solar energy technology employed is far less sophisticated than that of collectors using selective surface or evacuated tubes. The collector-adsorber is multi-tubular with an opaque black radiation-absorbing surface, and thermal insulated by means of transparent covers, the so-called transparent insulation material (TIM). The solar radiation hits on both faces of the tubes by means of semi-cylindrical reflectors. It is shown the results of tests carried out in a region of Brazil close to the Equator, on days characterized by the predominant cloud cover degree. Three cycles have been analyzed: one with clear sky, another with partially cloudy sky, and a third under entirely cloudy sky. The maximum regenerating temperatures were 100.1, 87.3 and 92.7 °C, with an ice production of 6.05, 2.10 and 0 kg by square meter of projected area, for cycles of clear sky, partially cloudy and overcast nights, respectively.     

Decomposition of repetition priming processes in word translation.

Translation in fluent bilinguals requires comprehension of a stimulus word and subsequent production, or retrieval and articulation, of the response word. Four repetition-priming experiments with Spanish–English bilinguals (N = 274) decomposed these processes using selective facilitation to evaluate their unique priming contributions and factorial combination to evaluate the degree of process overlap or dependence. In Experiment 1, symmetric priming between semantic classification and translation tasks indicated that bilinguals do not covertly translate words during semantic classification. In Experiments 2 and 3, semantic classification of words and word-cued picture drawing facilitated word-comprehension processes of translation, and picture naming facilitated word-production processes. These effects were independent, consistent with a sequential model and with the conclusion that neither semantic classification nor word-cued picture drawing elicits covert translation. Experiment 4 showed that 2 tasks involving word-retrieval processes—written word translation and picture naming—had subadditive effects on later translation. Incomplete transfer from written translation to spoken translation indicated that preparation for articulation also benefited from repetition in the less-fluent language. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Minor distortions with major consequences: correcting distortions in imaging spectrographs

Projective transformation is a mathematical correction (implemented in software) used in the remote imaging field to produce distortion-free images. We present the application of projective transformation to correct minor alignment and astigmatism distortions that are inherent in dispersive spectrographs. Patterned white-light images and neon emission spectra were used to produce registration points for the transformation. Raman transects collected on microscopy and fiber-optic systems were corrected using established methods and compared with the same transects corrected using the projective transformation. Even minor distortions have a significant effect on reproducibility and apparent fluorescence background complexity. Simulated Raman spectra were used to optimize the projective transformation algorithm. We demonstrate that the projective transformation reduced the apparent fluorescent background complexity and improved reproducibility of measured parameters of Raman spectra. Distortion correction using a projective transformation provides a major advantage in reducing the background fluorescence complexity even in instrumentation where slit-image distortions and camera rotation were minimized using manual or mechanical means. We expect these advantages should be readily applicable to other spectroscopic modalities using dispersive imaging spectrographs.     

Energy-band engineering for improved charge retention in fully self-aligned double floating-gate single-electron memories

We present a new fully self-aligned single-electron memory with a single pair of nano floating gates, made of different materials (Si and Ge). The energy barrier that prevents stored charge leakage is induced not only by quantum effects but also by the conduction-band offset that arises between Ge and Si. The dimensions and position of each floating gate are well-defined and controlled. The devices exhibit a long retention time and single-electron injection at room temperature.     

Quantitative photochemical immobilization of biomolecules on planar and corrugated substrates: a versatile strategy for creating functional biointerfaces

Methods for the generation of substratespresenting biomolecules in a spatially controlled manner are enabling tools for applications in biosensor systems, microarray technologies, fundamental biological studies and biointerface science. We have implemented a method to create biomolecular patterns by using light to control the direct covalent immobilization of biomolecules onto benzophenone-modified glass substrates. We have generated substrates presenting up to three different biomolecules patterned in sequence, and demonstrate biomolecular photopatterning on corrugated substrates. The chemistry of the underlying monolayer was optimized to incorporate poly(ethylene glycol) to enable adhesive cell adhesion onto patterned extracellular matrix proteins. Substrates were characterized with contact angle goniometry, AFM, and immunofluorescence microscopy. Importantly, radioimmunoassays were performed to quantify the site density of immobilized biomolecules on photopatterned substrates. Retained function of photopatterned proteins was demonstrated both by native ligand recognition and cell adhesion to photopatterned substrates, revealing that substrates generated with this method are suitable for probing specific cell receptor-ligand interactions. This molecularly general photochemical patterning method is an enabling tool for the creation of substrates presenting both biochemical and topographical variation, which is an important feature of many native biointerfaces.     

Near unity photon-to-electron conversion efficiency of photoelectrochemical cells built on cationic water-soluble porphyrins electrostatically decorated onto thin-film nanocrystalline SnO₂ surface

Thin transparent SnO(2) films have been surface modified with cationic water-soluble porphyrins for photoelectrochemical investigations. Free-base and zinc(II) derivatives of three types of cationic water-soluble porphyrins, (P)M, viz., tetrakis(N-methylpyridyl)porphyrin chloride, (TMPyP)M, tetrakis(trimethylanilinium)porphyrin chloride, (TAP)M, and tetrakis(4'-N-methylimidazolyl-phenyl)porphyrin iodide, (TMIP)M, (M = 2H or Zn) are employed. The negative surface charge and the porous structure of SnO(2) facilitated binding of positively charged porphyrins via electrostatic interactions, in addition to strong electronic interactions in the case of (TMPyP)M binding to nanocrystalline SnO(2). The SnO(2)-porphyrin binding in solution was probed by absorption spectroscopy which yielded apparent binding constants in the range of 1.5-2.6 × 10(4) M(-1). Both steady-state and time-resolved fluorescence studies revealed quenching of porphyrin emission upon binding to SnO(2) in water suggesting electron injection from singlet excited porphyrin to SnO(2) conduction band. Addition of LiClO(4) weakened the ion-paired porphyrin-SnO(2) binding as revealed by reversible emission changes. Over 80% of the quenched fluorescence was recovered in the case of (TMPyP)M and (TAP)M compounds but not for (TMIP)M suggesting stronger binding of the latter to SnO(2) surface. Photoelectrochemical studies performed on FTO/SnO(2)/(P)M electrodes revealed incident photon-to-current conversion efficiencies (IPCE) up to 91% at the peak maxima for the SnO(2)-dye modified electrodes, with very good on-off switchability. The high IPCE values have been attributed to the strong electrostatic and electronic interactions between the dye, (TMPyP)M and SnO(2) nanoparticles that would facilitate better charge injection from the excited porphyrin to the conduction band of the semiconductor. Electrochemical impedance spectral measurements of electron recombination resistance calculations were supportive of this assignment.