Third order non linear optical properties of ZnO:Al thin films prepared by spray pyrolysis

In this study, zinc oxide (ZnO) and aluminium doped zinc oxide (ZnO:Al) thin films were deposited by reactive chemical pulverization spray pyrolysis technique on heated glass substrates at 450degC. X-ray diffraction (XRD), scanning electron microscopy (SEM) and third harmonic generation (THG) are used to characterize their structure , morphology and nonlinear optical properties as a function of Al concentration (0, 3, 5, 7 at %). The intensity of third order non linear optical susceptibility increase by incorporation of aluminium. A strong value of susceptibility chi(3) was found for films with a good crystallinity

Study of CuI thin films properties for application as anode buffer layer in organic solar cells

After chemico-physical characterization of CuI thin films, the structures indium tin oxide (ITO) /CuI are systematically studied. We show that the morphology of the 3 nm thick CuI film depends on its deposition rate. To obtain smooth homogeneous CuI film, it is necessary to depose it at 0.005 nm/s. After optimization of the deposition conditions of CuI, it is shown that it behaves like a template for the organic layer. For instance, when the organic film is copper-phthalocyanine, the molecules which are usually perpendicular to the plane of the substrate lie parallel to it when deposited onto CuI. In a same way, when the electron donor is a prophyrin derivative, CuI allows to double the power conversion efficiency of the cells based on the heterojunction porphyrin/C-60. When CuI is used as anode buffer layer, it increases systematically the short circuit current, the open circuit voltage, thus the efficiency of the organic solar cell. These effects are related, not only to the improvement of the band matching between the ITO and the electron donor, but also to the templating effect of the CuI. Moreover, we show that the beneficial effect of CuI. is effective, not only with ITO, but also with fluorine doped tin oxide

Carbon-assisted chemical vapor deposition of hexagonal boron nitride

We show that in a low-pressure chemical vapor deposition (CVD) system, the residual oxygen and/or air play a crucial role in the mechanism of the growth of hexagonal boron nitride (h-BN) films on Ni foil 'enclosures'. Hexagonal-BN films grow on the Ni foil surface via the formation of an intermediate boric-oxide (BOx) phase followed by a thermal reduction of the BOx by a carbon source (either amorphous carbon powder or methane), leading to the formation of single-and bi-layer h-N. Low energy electron microscopy (LEEM) and diffraction (LEED) were used to map the number of layers over large areas; Raman spectroscopy, time-of-flight secondary ion mass spectrometry (ToF-SIMS), x-ray photoelectron spectroscopy (XPS) and scanning tunneling microscopy (STM) were used to characterize the structure and physical quality of the ultra-thin h-BN film. The growth procedure reported here leads to a better understanding and control of the synthesis of ultra-thin h-BN films

Detección rápida de la adulteración de aceite de argán con aceites de fritura usando espectroscopía de fluorescencia inducida por láser combinada con herramientas quimiométricas

There is a contentious need for robust and rapid methodologies for maintaining the authenticity of foods. The aim of this study was to detect and quantify argan oil adulteration using Laser Induced Fluorescence (LIF) spectroscopy coupled with chemometric methods. Principal Component Analysis (PCA) and Partial Least Squares Regression (PLSR) were used to assess argan oil authenticity; PCA was used to classify samples according to their quality and the PLS model to determine the amount of adulterants in pure argan oil. The correlation coefficient of the obtained model was about 0.99, with Root Mean Square Error of Prediction (RMSEP) and Standard Error of Prediction (SEP) of 2%. This study demonstrated the feasibility of LIF spectroscopy combined with chemometric tools to identify adulterants in pure argan oil from a percentage of adulteration, of 0.35 % without the need to destruct samples.Existe una necesidad de metodologías sólidas y rápidas para determinar la autenticidad de los alimentos. El objetivo de este estudio es detectar y cuantificar la adulteración del aceite de argán mediante espectroscopia de fluorescencia inducida por láser (LIF) junto con métodos quimiométricos. Se utilizaron el análisis de componentes principales (PCA) y la regresión de mínimos cuadrados parciales (PLSR) para evaluar la autenticidad del aceite de argán. Se utilizó PCA para clasificar las muestras según su calidad y el modelo PLS se aprovechó para determinar la cantidad de adulterantes en el aceite de argán puro. El coeficiente de correlación del modelo obtenido fue de alrededor de 0,99, el error cuadrático medio de la predicción (RMSEP) y el error estándar de predicción (SEP) del 2%. Este estudio demostró la viabilidad de la espectroscopia LIF combinada con herramientas quimiométricas que permiten identificar adulterantes en aceite de argán puro, sin necesidad de destruir muestras, a partir de un porcentaje de adulteración del 0,35 %

The surface science of quasicrystals

The surfaces of quasicrystals have been extensively studied since about 1990. In this paper we review work on the structure and morphology of clean surfaces, and their electronic and phonon structure. We also describe progress in adsorption and epitaxy studies. The paper is illustrated throughout with examples from the literature. We offer some reflections on the wider impact of this body of work and anticipate areas for future development. (Some figures in this article are in colour only in the electronic version

Effect of a hyper-protein diet on Wistar rats development and intestinal function

This study was designed to investigate the long-term effects of a high-protein diet on the functional and histological structure of the intestinal epithelium. Sixteen adult male Wistar rats (180 ± 2.27 g) were divided into two groups: 1) the control group, (n = 30) were fed a normal diet of 14% protein; 2) the P50- group (n = 30) were fed a 50% protein diet. The effects of a high-protein diet were studied over a periodof 2 months. Functional and morphological differences between the high-protein and control groups were compared. Internal organs (liver, stomach, lungs, heart, kidneys, spleen, intestine, skin, surrenalglands, white and brown adipose tissues) were removed from each sacrificed animal. The organs were weighed, and histological studies were performed on jejunal fragments. The weight of the P50 grouprats increased 79%, while the weight of the control-group increased 98% (p< 0.01 0.05). The weight of the white adipose tissue, the skeleton and the skin were significantly greater in control-group rats (p< 0.01). An important modification of the epithelial structure in the intestine was observed in rats of the P50 group. The average length of their villi was significantly reduced and there was a significantincrease in their IEL (p< 0.01). Our results indicate that ingestion of a protein-rich diet over a long period leads to modification of the histological structure of the intestinal epithelium, as indicated by;pronounced atrophy of mucosa; marked inflammatory infiltration of lymphocytes in the chorion; and many intra-epithelial lymphocytes

In situ observations of the atomistic mechanisms of Ni catalyzed low temperature graphene growth.

The key atomistic mechanisms of graphene formation on Ni for technologically relevant hydrocarbon exposures below 600 °C are directly revealed via complementary in situ scanning tunneling microscopy and X-ray photoelectron spectroscopy. For clean Ni(111) below 500 °C, two different surface carbide (Ni2C) conversion mechanisms are dominant which both yield epitaxial graphene, whereas above 500 °C, graphene predominantly grows directly on Ni(111) via replacement mechanisms leading to embedded epitaxial and/or rotated graphene domains. Upon cooling, additional carbon structures form exclusively underneath rotated graphene domains. The dominant graphene growth mechanism also critically depends on the near-surface carbon concentration and hence is intimately linked to the full history of the catalyst and all possible sources of contamination. The detailed XPS fingerprinting of these processes allows a direct link to high pressure XPS measurements of a wide range of growth conditions, including polycrystalline Ni catalysts and recipes commonly used in industrial reactors for graphene and carbon nanotube CVD. This enables an unambiguous and consistent interpretation of prior literature and an assessment of how the quality/structure of as-grown carbon nanostructures relates to the growth modes.L.L.P. acknowledges funding from Area di Ricerca Scientifica e Tecnologica of Trieste and from MIUR through Progetto Strategico NFFA. C.A. acknowledges support from CNR through the ESF FANAS project NOMCIS. C.A. and C.C. acknowledge financial support from MIUR (PRIN 2010-2011 nº 2010N3T9M4). S.B. acknowledges funding from ICTP TRIL program. S.H. acknowledges funding from ERC grant InsituNANO (n°279342). R.S.W. acknowledges funding from EPSRC (Doctoral training award), and the Nano Science & Technology Doctoral Training Centre Cambridge (NanoDTC). The help of C. Dri and F. Esch (design) and P. Bertoch and F. Salvador (manufacturing) in the realization of the high temperature STM sample holder is gratefully acknowledged. We acknowledge the Helmholtz-Zentrum-Berlin Electron storage ring BESSY II for provision of synchrotron radiation at the ISISS beamline and we thank the BESSY staff for continuous support of our experiments.This is the accepted manuscript. The final version is available from ACS at http://pubs.acs.org/doi/abs/10.1021/nn402927q

Risk of cervical abnormality after age 50 in women with previously negative smears

There is discussion over the benefit of continuing cervical screening in women over the age of 50 with a history of negative cytology. We aimed to determine the risk of abnormal cytology in such women. Screening history data from 1985 to 2003 were obtained for a cohort of 2 million women from the NHS cervical screening programme from four Health Authorities in England. The 57 651 women in the cohort who reached age 40 between 1 January 1985 and 31 December 1990 and had at least one routine or opportunistic smear between ages 50 and 54 were included in the analysis. Exposure groups (negative cytology history, negative but including inadequate smears, and positive history) were defined on the basis of screening histories from ages 40 to 49. Sixty-four percent (134/206) (95% CI: 57–71%) of the moderate dyskaryosis or worse lesions at ages over 50 were detected from women in the negative smear history group. After allowance for time since last negative smear, the relative risk for the first primary smear over the age of 50 having moderate dyskaryosis or worse decreased from 0.60 (95% CI: 0.41–0.84) for two negative smear episodes to 0.25 (95% CI: 0.10–0.56) for four negative smear episodes, compared with the positive history group. If screening were discontinued for all women over 50 with a negative history, the majority of cytological abnormalities now being detected at these ages that lead directly to referral to colposcopy would be missed

CVD-Enabled Graphene Manufacture and Technology.

Integrated manufacturing is arguably the most challenging task in the development of technology based on graphene and other 2D materials, particularly with regard to the industrial demand for “electronic-grade” large-area films. In order to control the structure and properties of these materials at the monolayer level, their nucleation, growth and interfacing needs to be understood to a level of unprecedented detail compared to existing thin film or bulk materials. Chemical vapor deposition (CVD) has emerged as the most versatile and promising technique to develop graphene and 2D material films into industrial device materials and this Perspective outlines recent progress, trends, and emerging CVD processing pathways. A key focus is the emerging understanding of the underlying growth mechanisms, in particular on the role of the required catalytic growth substrate, which brings together the latest progress in the fields of heterogeneous catalysis and classic crystal/thin-film growth.Funding from the ERC (Grant No. 279342, InSituNANO) and EPSRC (Grant No. EP/K016636/1, GRAPHTED) is acknowledged. R.S.W. acknowledges a research fellowship from St. John’s College, Cambridge.This is the final version of the article. It first appeared from ACS via http://dx.doi.org/10.1021/acs.jpclett.5b0105

Kroppenstedtia pulmonis sp. nov. and Kroppenstedtia sanguinis sp. nov., isolated from human patients

Three human clinical strains (W9323T, X0209T and X0394) isolated from lung biopsy, blood and cerebral spinal fluid, respectively, were characterized using a polyphasic taxonomic approach. Comparative analysis of the 16S rRNA gene sequences showed the three strains belonged to two novel branches within the genus Kroppenstedtia: 16S rRNA gene sequence analysis of W9323T showed closest sequence similarity to Kroppenstedtia eburnea JFMB-ATE T (95.3 %), Kroppenstedtia guangzhouensis GD02T (94.7 %) and strain X0209T (94.6 %); sequence analysis of strain X0209T showed closest sequence similarity to K. eburnea JFMB-ATE T (96.4 %) and K. guangzhouensis GD02T (96.0 %). Strains X0209T and X0394 were 99.9 % similar to each other by 16S rRNA gene sequence analysis. The DNA-DNA relatedness was 94.6 %, confirming that X0209T and X0394 belong to the same species. Chemotaxonomic data for strains W9323T and X0209T were consistent with those described for the genus Kroppenstedtia: whole-cell peptidoglycan contained LLdiaminopimelic acid; the major cellular fatty acids were iso-C15 and anteiso-C15; and the major menaquinone was MK-7. Different endospore morphology and carbon utilization profiles of strains W9323T and X0209T supported by phylogenetic analysis enabled us to conclude that the strains represent two new species within the genus Kroppenstedtia, for which the names Kroppenstedtia pulmonis sp. nov. (type strain W9323T =DSM 45752 T) and Kroppenstedtia sanguinis sp. nov. (type strain X0209T =DSM 45749T=CCUG 38657 T) are proposed