68 research outputs found

    Shaping caustics into propagation-invariant light

    Full text link
    Structured light has revolutionized optical particle manipulation and nano-scale material processing. In particular, propagation-invariant structured light fields, such as Bessel beams, have enabled applications that require robust intensity distributions. Their self-healing nature facilitates imaging with enhanced resolution e.g. in light-sheet microscopy. The prominent high-intensity features of propagation-invariant fields such as Airy, Bessel, and Mathieu beams can be understood in terms of caustics. While these beams have found many applications in material processing and trapping, these technologies would greatly benefit from structured, controllable intensities in a variety of shapes well beyond the standard families of propagation-invariant beams. Here we generalize propagation-invariant beams by tailoring their caustics through two different methods. We illustrate these approaches by implementing various tailored propagation-invariant beams experimentally, whose patterns range from simple geometric shapes to complex configurations such as words. This approach clarifies that the known solutions are a small subset of a far more general set of propagation-invariant fields with intensity maxima concentrated around any desired curve

    Genotoxic activity of the Fumonisin B1 mycotoxin in cultures of bovine lymphocytes

    Get PDF
    The fumonisins, produced by fungi that infest foodstuffs, in particular corn, are responsible for a series of illnesses and toxicosis in various species of animals, including humans. There is still not detailed information about the genotoxic and mutagenic activity of Fumonisin B1 (FB1), but it is clear that it interferes with growth control, differentiation and cellu- lar apoptosis. The purpose of this study was to assess the genotoxic potential of Fumonisin B1 using in vitrocultures of bovine lymphocytes, through the calculation of the ‘mitotic index’ (MI), the frequency of ‘sister chromatid exchange’ (SCE) and the ‘micronucleus test’ (MN). The bovine lymphocytes were exposed to different concentrations of FB1 (25, 50 and 100 µM) in order to find out which amount is sufficient to cause a reduction in the mitotic potential of the cells, the onset of MN and a higher frequency of SCE. The results obtained show a considerable reduction in the ‘mitotic index’ with a FB1 concentration of 50 µM, an increase in the frequency of MN with a concentration of 50 µM and a significant increase in the SCE with a concentration of 100 µM. In the light of the information we have obtained, compared with that of other Authors, we feel that the genotoxic poten- tial of FB1 has been underestimated until now and should, therefore, be reconsidered

    Macro Minerals and Trace Elements in Milk of Dairy Buffaloes and Cows Reared in Mediterranean Areas

    Get PDF
    Aim of this study was to evaluate the differences in Ca, P, K, Na, Mg, Zn, Fe, Cu, Mn, Se, Mo, Co, Li, B, Ti, Rb, and Sr concentrations in milk from buffaloes and cows reared in the same farm in Mediterranean areas and fed diets including the same ingredients. Individual milk samples were obtained from 32 Mediterranean buffaloes and 29 Italian Friesian cows and samples of milk, dietary ingredients and drinking water were analyzed for the investigated chemical elements by inductively coupled plasma-mass spectrometry. Data about milk element concentrations were processed by one-way analysis of variance. Buffalo milk contains higher concentrations of Ca, P, Mg, Zn, Fe, Cu, B, Ti, and Sr, and lower concentrations of K, Na, Mo, Li, and Rb compared to cow milk, whereas milk from both species contains similar concentrations of Mn, Se, and Co. The concentrations of the investigated elements in the diet were similar for both species and the differences observed between buffalo and cow milk were not dependent on environmental factors

    Ni Mg mixed metal oxides for p-type dye-sensitized solar cells

    Get PDF
    Mg Ni mixed metal oxide photocathodes have been prepared by a mixed NiCl2/MgCl2 sol-gel process. The MgO/NiO electrodes have been extensively characterized using physical and electrochemical methods. Dye-sensitized solar cells have been prepared from these films and the higher concentrations of MgO improved the photovoltage of these devices, however, there was a notable drop in photocurrent with increasing Mg2+. Charge extraction and XPS experiments revealed that the cause of this was a positive shift in the energy of the valence band which decreased the driving force for electron transfer from the NiO film to the dye and therefore the photocurrent. In addition, increasing concentrations of MgO increases the volume of pores between 0.500 to 0.050 μm, while reducing pore volumes in the mesopore range (less than 0.050 μm) and lowering BET surface area from approximately 41 down to 30 m2 g-1. A MgO concentration of 5% was found to strike a balance between the increased photovoltage and decreased photocurrent, possessing a BET surface area of 35 m2 g-1 and a large pore volume in both the meso and macropore range, which lead to a higher overall power conversion efficiency than NiO alone

    Sequence, "subtle" alternative splicing and expression of the CYYR1 (cysteine/tyrosine-rich 1) mRNA in human neuroendocrine tumors

    Get PDF
    BACKGROUND: CYYR1 is a recently identified gene located on human chromosome 21 whose product has no similarity to any known protein and is of unknown function. Analysis of expressed sequence tags (ESTs) have revealed high human CYYR1 expression in cells belonging to the diffuse neuroendocrine system (DNES). These cells may be the origin of neuroendocrine (NE) tumors. The aim of this study was to conduct an initial analysis of sequence, splicing and expression of the CYYR1 mRNA in human NE tumors. METHODS: The CYYR1 mRNA coding sequence (CDS) was studied in 32 NE tumors by RT-PCR and sequence analysis. A subtle alternative splicing was identified generating two isoforms of CYYR1 mRNA differing in terms of the absence (CAG(- )isoform, the first described mRNA for CYYR1 locus) or the presence (CAG(+ )isoform) of a CAG codon. When present, this specific codon determines the presence of an alanine residue, at the exon 3/exon 4 junction of the CYYR1 mRNA. The two mRNA isoform amounts were determined by quantitative relative RT-PCR in 29 NE tumors, 2 non-neuroendocrine tumors and 10 normal tissues. A bioinformatic analysis was performed to search for the existence of the two CYYR1 isoforms in other species. RESULTS: The CYYR1 CDS did not show differences compared to the reference sequence in any of the samples, with the exception of an NE tumor arising in the neck region. Sequence analysis of this tumor identified a change in the CDS 333 position (T instead of C), leading to the amino acid mutation P111S. NE tumor samples showed no significant difference in either CYYR1 CAG(- )or CAG(+ )isoform expression compared to control tissues. CYYR1 CAG(- )isoform was significantly more expressed than CAG(+ )isoform in NE tumors as well as in control samples investigated. Bioinformatic analysis revealed that only the genomic sequence of Pan troglodytes CYYR1 is consistent with the possible existence of the two described mRNA isoforms. CONCLUSION: A new "subtle" splicing isoform (CAG(+)) of CYYR1 mRNA, the sequence and the expression of this gene were defined in a large series of NE tumors

    Evaluation of Physicochemical and Microbial Properties of Extracts from Wine Lees Waste of Matelica’s Verdicchio and Their Applications in Novel Cosmetic Products

    Get PDF
    Wine lees are sediments deposited on the walls and bottom of barrels resulting from wine fermentation and mainly consist of yeasts. Saccharomyces cerevisiae extracts, rich in beneficial components for the skin, have already been used in cosmesis, while wine lees have not been well exploited by the cosmetics industry yet. The aim of this work was the full characterization of the wine lees from Verdicchio's wine, with the aim to exploit it as a beneficial ingredient in new cosmetic products. After mapping the microbial composition of the sample waste, the parameters for the sonication extraction process were optimized and the physicochemical properties of the extract were analyzed. The efficiency of the aqueous extraction-and in particular the yeast cell lysis necessary for the release of proteins from the cell-was assessed by evaluating cell shape and size, and protein release, under scanning electron microscopy (SEM), dynamic light scattering (DLS) and Bradford's protein assays. Thus, the total phenol content and antioxidant capacity of the supernatant recovered from native and sonicated lees were determined by Folin-Ciocalteu's and spectrophotometric assays, respectively. To quantify the heavy metals and highlight the presence of microelements beneficial for the skin, inductively coupled plasma-mass spectrometry (ICP-MS) was applied. In vitro metabolic activity and cytotoxicity were tested on both HaCat keratinocytes and human gingival fibroblasts, showing that wine lees are safe for skin's cells. The results show that sonicated lees appear to be more interesting than native ones as a consequence of the release of the active ingredients from the cells. Due to the high antioxidant capacity, content of beneficial elements for skin and an appropriate microbiologic profile, wine lees were included in five new solid cosmetic products and tested for challenge test, compatibility with human skin, sensory analysis, trans epidermal water loss (TEWL) and sebometry
    • …
    corecore