Study of the photon down‐conversion effect produced by thin silicon‐rich oxide films on silicon solar cells

In the present work, we studied the photon down‐conversion effect produced by thin films of silicon oxide with embedded silicon nanocrystals also called silicon‐rich oxide (SRO). These films have been used to absorb high energy light and the re‐emission of two or more low energy photons (~1.1 eV) with the goal of improving the external quantum efficiency and consequently the conversion efficiency of silicon solar cells. According to our results, the incorporation of a thin SRO film on the solar cell surface increases the short circuit current and the FF of the silicon solar cells; the enhancement of spectral response is due to the high photoluminescence intensity of the SRO in the visible region when irradiated with UV light. An improvement of 38% in the solar cell efficiency has been observed in our particular solar cell fabrication process by the use of an SRO film with high photoluminescence intensity, which replaces the conventional silicon dioxide film. Copyright © 2016 John Wiley & Sons, Ltd.     

Computational evolutionary inverse lagrangian puff model

This article presents a model based on the principles of evolutionary computation and on the principles of dispersion of an Inverse lagrangian puff model of the type Backward gaussian puff tracking in order to determine the spatial behavior over time of the concentration for PM_2.5 and PM₁₀ in a study area.     

Multiplex Real-time PCR for the Simultaneous Detection of Salmonella spp. and Listeria monocytogenes in Food Samples

In this study, we have developed a rapid method for the simultaneous detection of Listeria monocytogenes and Salmonella spp. in foods, combining culture enrichment and a multiplex real-time polymerase chain reaction (PCR). The assay used two pre-existing primer-probe sets, labelled with different reporter dyes to enable the direct distinction of the original contaminating agent. Amplification efficiency and inclusivity/exclusivity of the combined assay was successfully assessed. The overall process included the culture enrichment based on the ISO standard, consisting of 24 h incubation in appropriate media (Half Fraser Broth for Listeria and buffered peptone water (BPW) for Salmonella), followed by a single DNA extraction of mixed enrichment aliquots, and real-time PCR detection of the hly and bipA genes of L. monocytogenes and Salmonella spp., respectively. An internal amplification control, co-amplified during the PCR run, was included in the assay to verify the results. The tool was evaluated with a variety of artificially inoculated samples of fresh products and ready to eat and cooked dishes, allowing the identification of the target pathogens down to 5 CFU/25 g of food sample. Moreover, the analysis saved a considerable amount of time compared to the ISO standard, being performed in less than 2 working days. Specificity, sensitivity and accuracy were satisfactorily tested by comparison to the standard methods ISO 11290-2:1998 and ISO 6579:2002, suggesting that the tool has a great potential as a reliable alternative for food safety assurance providing rapid detection of both pathogens in food samples.     

The Effective Factors on the Structure of Butter and Other Milk Fat‐Based Products

Butter and other milk fat‐based products are valuable products for the dairy industry due to their unique taste, their textural characteristics, and nutritional value. However, an increased consumer demand for low‐fat‐based products increases the need for an increased essential understanding of the effective factors governing the structure of milk fat‐based products. Today, 2 manufacturing techniques are available: the churning method and the emulsification method. The first is typically used for production of butter with a globular structure, which has become increasingly popular to obtain low‐fat‐based products, typically without presence of milk fat globules. The microstructure of milk fat‐based products is strongly related to their structural rheology, hence applications. Structural behavior is not determined by one single parameter, but by the interactions between many. This complexity is reviewed here. Parameters such as thermal treatment of cream prior to butter making, water content, and chemical composition influence not only crystal polymorphism, but also the number and sizes of fat crystals. The number of crystal–crystal interactions formed within the products is related to product hardness. During storage, however, postcrystallization increases the solid fat content and strengthens the fat crystal network. The fat crystal network is strengthened by the formation of more and stronger crystal–crystal interactions due to mechanically interlinking of fat crystals, which occurs during crystal growth. Postcrystallization is directly linked to chemical composition. The initially observed microstructural difference causing different rheological behavior will disappear during storage due to postcrystallization and formation of more crystal–crystal interactions.     

Essential and non essential amino acid content of infant cereals in different stages of industrial processing and its relationship with chemical scores of protein quality

The effect of technological process on essential and non essential amino acids contents in infant cereals, the protein and essential amino acids infant dietary requirements cover by infant cereals, and its quality using some chemical scores has been studied. Mix of raw flours, mix of roasted flours, mix of enzymatically, hydrolysed and drum dried flours and commercial infant cereals of four different types of infant cereals: "Multicereal" and "Wheat" (both with gluten), "Growth" and "Rice and carrot" (both gluten free) were evaluated. The technological process only show a significant effect on lysine, arginine (P < 0.05) and valine (P < 0.01) contents in "Rice and carrot" infant cereal. Protein of any studied infant cereals covers 17.4% of the daily infant requirements in, while for essential amino acids will cover about 25 to 200% until the third year of life. As we expected, the limitant amino acid was lysine in all flours. Chemical scores only were affected by technological treatment in "Rice and carrot" infant cereal, showing the gluten-free infant cereals higher values (36.7-69.5%) than gluten infant cereals (18.1%-30.7%) at the end of the processing. It should be standing out "Growth" infant cereal, because of it has a higher lysine content than other infant cereals due to the main ingredients rice and corn.     

Detection of bacterial infection of agave plants by laser-induced fluorescence

Greenhouse-grown plants of Agave tequilana Weber var. azul were inoculated with Erwinia carotovora, the causal agent of stem soft rot. We investigated the laser-induced fluorescence (LIF) of agave plants to determine whether LIF can be used as a noninvasive sensing tool for pathological studies. The LIF technique was also investigated as a means of detecting the effect of the polyamine biosynthesis inhibitor beta-hydroxyethylhydrazine as a bactericide against the pathogenic bacterium Erwinia carotovora. A He-Ne laser at 632.8 nm was used as the excitation source, and in vivo fluorescence emission spectra were recorded in the 660-790-range. Fluorescence maxima were at 690 and 740 nm. The infected plants that were untreated with the bactericide showed a definite increase in fluorescence intensity at both maxima within the first three days after infection. Beginning on the fifth day, a steady decrease in fluorescence intensity was observed, with a greater effect at 740 than at 690 nm. After 30 days there was no fluorescence. The infected plants that had been treated with the bactericide showed no significant change in fluorescence compared with that of the uninfected plants. The ratio of fluorescence intensities was determined to be F 690 nm/F 740 nm for all treatments. These studies indicate that LIF measurements of agave plants may be used for the early detection of certain types of disease and for determining the effect of a bactericide on bacteria. The results also showed that fluorescence intensity ratios can be used as a reliable indicator of the progress of disease.     

Cellular fluorescent indicators and voltage/ion probe reader (VIPR) tools for ion channel and receptor drug discovery

High throughput functional assays are increasingly relied upon to generate early and novel discovery leads for drug development. Ion transport proteins including channels, transporters, and pumps play central roles in cellular bioenergetics, excitability, and a multitude of other biological functions. Facile, robust methods for detecting ion transport activity in both native and heterologous systems is desirable for rapid functional analysis and drug discovery for these difficult but important targets. Here we discuss cell-compatible fluorescent probes, functional assays, and VIPR instrumentation that are used to monitor real-time target activity and screen large chemical libraries for potent and selective modulators. Advances and issues for both exogenously applied and fluorescent protein probes of cellular membrane potential, Ca2+, Cl-, and pH are addressed. High throughput screening (HTS) compatible, rapid kinetic and fluorescence resonance energy transfer (FRET) assays are emphasized, in particular the use of voltage-sensitive FRET probes to assay ion channel activity in single cells and 96/384-well formats.     

Scientists' performance and consolidation of research teams in Biology and Biomedicine at the Spanish Council for Scientific Research

Summary Empirical evidence is given on how membership in a consolidated, well-established research team provides researchers with some competitive advantage as compared to their colleagues in non-consolidated teams. Data were obtained from a survey of researchers ascribed to the 'Biology and Biomedicine' area of the Spanish Council for Scientific Research, as well as from their curricula vitae. One quarter of the scientists work as members of teams in the process of consolidation. Our findings illustrate the importance, for the development and consolidation of research teams, of the availability of a minimum number of researchers with a permanent position and of a minimum number of support staff and non-staff personnel (mainly post-doctoral fellows). Consolidation of research teams has a clear influence on the more academic-oriented quantitative indicators of the scientific activity of individuals. Researchers belonging to consolidated teams perform quantitatively better than their colleagues in terms of the number of articles published in journals covered in the Journal Citation Reports, but not in terms of the impact of these publications. Consolidation favours publication, but not patenting, and it also has a positive effect on the academic prestige of scientists and on their capacity to train new researchers. It does not significantly foster participation in funded R&D projects, nor does it influence the establishment of international collaborations. Impact is influenced to a remarkable degree by seniority and professional background, and is significantly greater for young scientists who have spent time abroad at prestigious research laboratories.     

Hydrogen evolution reaction on W oriented crystals

Hydrogen evolution reaction was studied on (111) and (100) tungsten single crystals. Differences in Tafel slope were observed for fresh specimens. The double Tafel behaviour appeared after polishing.     

Nutritional and antioxidant status of an institutionalized elderly group in Murcia (Spain)

The aging of the population is giving rise to a large number of studies aimed at improving the quality of life, considering diet as a major contributing factor in this life stage. The objectives of the present study were to evaluate the nutritional status of a group of institutionalized elderly in Murcia, Spain, and to relate the diet to anthropometric and biochemical indices, paying special attention to total antioxidant status. The dietary evaluation showed excessive intakes of proteins and lipids, and deficiencies in those of carbohydrates, dietary fiber, zinc, iodine and vitamins A, E and D. The high proportion of overweight observed were not significantly correlated to the energy intakes. Although total plasma antioxidant status was low (0.62 mM eq Trolox and 0.98 mM eq Fe(II)) compared with reference values, estimated oxidative risk in this group of elderly was low according to plasma levels of vitamins C, A & E.