Picosecond Laser Surface Micro/Nano Texturing of Stainless Steel as a Method to Reduce the Adhesion of Bacteria.

Biofilm formation and colonization is initiated by bacterial attachment followed by bacterial adhesion and retention on a surface. The buildup of biofilms may result in related health problems in the medical field and potential biofouling issues in industrial settings leading to increased economic burden. The design and manufacture surfaces that prevent bacterial attachment, retention and biofilm formation through their physical structure and chemical properties provides a potential solution to tackle such issues. Laser surface texturing provides a crucial role for the production of different antifouling surface patterns for use in a diverse range of applications in different medical or industrial fields. In the present work, a 1064 nm Nd:YVO4 Picosecond laser was used to produce a range of textures on 316L stainless steel (SS) substrates. Results showed that the Sa values and wettability of the surfaces all increased when compared to the control following laser treatment. This work demonstrated that on all the surfaces, for all the assays, the number of adhesive bacteria on the laser textured surfaces was reduced compared to the untreated substrate. One surface was demonstrated to be the best antiadhesive surface which was of higher roughness and superhydrophobicit

The detection and quantification of food components on stainless steel surfaces following use in an operational bakery

© 2019 Institution of Chemical Engineers Food preparation areas in commercial bakeries present surfaces for continual organic fouling. The detection of retained food components and microorganisms on stainless steel surfaces situated for one month in the weighing in area, pastry and confectionary production areas of a bakery were investigated using different methods. Scanning electron microscopy demonstrated the morphology of the material on the surfaces from all three areas, with the weighing in area demonstrating a more even coverage of material. Differential staining assays demonstrated a high percentage coverage of organic material heterogeneously distributed across the surfaces. Differential staining also demonstrated that the amount of organic material on the surface from the confectionary area was significantly greater than from both the pastry and weighing in areas. Although, UV at 353 nm did not detect residual surface fouling, performance of the UV detection was optimised and demonstrated that the residual organic material on the weighing in area and the pastry samples was best illuminated at 510–560 nm, and from the confectionary area of the bakery at 590–650 nm. ATP bioluminescence revealed the confectionary production area contained the highest level of biofouling. Contact plates determined that only low microbial counts (≤2 CFU/cm2) were recovered from the surfaces. Changes in the physicochemistry (increased hydrophobicity) demonstrated that all the surfaces were fouled (ΔGiwi −26.8 mJ/m2 to −45.4 mJ/m2). Fourier Transform Infra-Red Spectroscopy (FTIR) demonstrated that all the surfaces had retained fats, carbohydrates and proteins. This work suggests that a range of methods may be needed to fully detect organic and microbial fouling

The effect of surface properties of polycrystalline, single phase metal coatings on bacterial retention

In the food industry microbial contamination of surfaces can result in product spoilage which may lead to potential health problems of the consumer. Surface properties can have a substantial effect on microbial retention. The surface characteristics of chemically different coatings (Cu, Ti, Mo, Ag, Fe) were defined using white light profilometry (micro-topography and surface features), atomic force microscopy (nano-topography) and physicochemical measurements. The Ag coating had the greatest topography measurements and Fe and Mo the least. Mo was the most hydrophobic coating (lowest γAB,γ+, γ−) whilst Ag was the most hydrophilic (greatest γAB,γ+, γ−). The physicochemical results for the Fe, Ti and Cu coatings were found to lie between those of the Ag and Mo coatings. Microbiological retention assays were carried out using Listeria monocytogenes, Escherichia coli and Staphylococcus aureus in order to determine how surface properties influenced microbial retention. It was found that surface chemistry had an effect on microbial retention, whereas the shape of the surface features and nano-topography did not. L. monocytogenes and S. aureus retention to the surfaces were mostly affected by surface micro-topography, whereas retention of E. coli to the coatings was mostly affected by the coating physicochemistry. There was no trend observed between the bacterial cell surface physicochemistry and the coating physicochemistry. This work highlights that different surface properties may be linked to factors affecting microbial retention hence, the use of surface chemistry, topography or physicochemical factors alone to describe microbial retention to a surface is no longer adequate. Moreover, the effects of surface parameters on microbial retention should be considered individually for each bacterial genus

A module-based analytical strategy to identify novel disease-associated genes shows an inhibitory role for interleukin 7 Receptor in allergic inflammation

<p>Abstract</p> <p>Background</p> <p>The identification of novel genes by high-throughput studies of complex diseases is complicated by the large number of potential genes. However, since disease-associated genes tend to interact, one solution is to arrange them in modules based on co-expression data and known gene interactions. The hypothesis of this study was that such a module could be a) found and validated in allergic disease and b) used to find and validate one ore more novel disease-associated genes.</p> <p>Results</p> <p>To test these hypotheses integrated analysis of a large number of gene expression microarray experiments from different forms of allergy was performed. This led to the identification of an experimentally validated reference gene that was used to construct a module of co-expressed and interacting genes. This module was validated in an independent material, by replicating the expression changes in allergen-challenged CD4⁺cells. Moreover, the changes were reversed following treatment with corticosteroids. The module contained several novel disease-associated genes, of which the one with the highest number of interactions with known disease genes, <it>IL7R</it>, was selected for further validation. The expression levels of <it>IL7R </it>in allergen challenged CD4⁺cells decreased following challenge but increased after treatment. This suggested an inhibitory role, which was confirmed by functional studies.</p> <p>Conclusion</p> <p>We propose that a module-based analytical strategy is generally applicable to find novel genes in complex diseases.</p

Potential migration and subjective well-being in Europe

By examining the preferences over migration destinations of those revealing a desire to permanently leave their country, this paper provides new evidence on the relevance of subjective measures for cross country comparisons. While hard statistics such as GDP per capita and unemployment rates are commonly used to measure a country’s success, this analysis reveals that people’s preferences over alternative migration destinations are better explained by average levels of life satisfaction in the destination country. Aggregated measures of subjective well-being are, therefore, useful for international comparisons as they better reflect what makes some countries more attractive than others

Expression of therapeutic misconception amongst Egyptians: a qualitative pilot study

<p>Abstract</p> <p>Background</p> <p>Studies have shown that research participants fail to appreciate the difference between research and medical care, labeling such phenomenon as a "therapeutic misconception" (TM). Since research activity involving human participants is increasing in the Middle East, qualitative research investigating aspects of TM is warranted. Our objective was to assess for the existence of therapeutic misconception amongst Egyptians.</p> <p>Methods</p> <p><it>Study Tool: </it>We developed a semi-structured interview guide to elicit the knowledge, attitudes, and perspectives of Egyptians regarding medical research.</p> <p><it>Setting: </it>We recruited individuals from the outpatient settings (public and private) at Ain Shams University in Cairo, Egypt.</p> <p><it>Analysis: </it>Interviews were taped, transcribed, and translated. We analyzed the content of the transcribed text to identify the presence of a TM, defined in one of two ways: TM₁= inaccurate beliefs about how individualized care can be compromised by the procedures in the research and TM₂= inaccurate appraisal of benefit obtained from the research study.</p> <p>Results</p> <p>Our findings showed that a majority of participants (11/15) expressed inaccurate beliefs regarding the degree with which individualized care will be maintained in the research setting (TM₁) and a smaller number of participants (5/15) manifested an unreasonable belief in the likelihood of benefits to be obtained from a research study (TM₂). A total of 12 of the 15 participants were judged to have expressed a TM on either one of these bases.</p> <p>Conclusion</p> <p>The presence of TM is not uncommon amongst Egyptian individuals. We recommend further qualitative studies investigating aspects of TM involving a larger sample size distinguished by different types of illnesses and socio-economic variables, as well as those who have and have not participated in clinical research.</p

Defining Reference Sequences for Nocardia Species by Similarity and Clustering Analyses of 16S rRNA Gene Sequence Data

International audienceBACKGROUND: The intra- and inter-species genetic diversity of bacteria and the absence of 'reference', or the most representative, sequences of individual species present a significant challenge for sequence-based identification. The aims of this study were to determine the utility, and compare the performance of several clustering and classification algorithms to identify the species of 364 sequences of 16S rRNA gene with a defined species in GenBank, and 110 sequences of 16S rRNA gene with no defined species, all within the genus Nocardia. METHODS: A total of 364 16S rRNA gene sequences of Nocardia species were studied. In addition, 110 16S rRNA gene sequences assigned only to the Nocardia genus level at the time of submission to GenBank were used for machine learning classification experiments. Different clustering algorithms were compared with a novel algorithm or the linear mapping (LM) of the distance matrix. Principal Components Analysis was used for the dimensionality reduction and visualization. RESULTS: The LM algorithm achieved the highest performance and classified the set of 364 16S rRNA sequences into 80 clusters, the majority of which (83.52%) corresponded with the original species. The most representative 16S rRNA sequences for individual Nocardia species have been identified as 'centroids' in respective clusters from which the distances to all other sequences were minimized; 110 16S rRNA gene sequences with identifications recorded only at the genus level were classified using machine learning methods. Simple kNN machine learning demonstrated the highest performance and classified Nocardia species sequences with an accuracy of 92.7% and a mean frequency of 0.578. CONCLUSION: The identification of centroids of 16S rRNA gene sequence clusters using novel distance matrix clustering enables the identification of the most representative sequences for each individual species of Nocardia and allows the quantitation of inter- and intra-species variability

New ophthalmosaurid ichthyosaurs from the European lower cretaceous demonstrate extensive ichthyosaur survival across the Jurassic–Cretaceous boundary

Background Ichthyosauria is a diverse clade of marine amniotes that spanned most of the Mesozoic. Until recently, most authors interpreted the fossil record as showing that three major extinction events affected this group during its history: one during the latest Triassic, one at the Jurassic–Cretaceous boundary (JCB), and one (resulting in total extinction) at the Cenomanian-Turonian boundary. The JCB was believed to eradicate most of the peculiar morphotypes found in the Late Jurassic, in favor of apparently less specialized forms in the Cretaceous. However, the record of ichthyosaurs from the Berriasian–Barremian interval is extremely limited, and the effects of the end-Jurassic extinction event on ichthyosaurs remains poorly understood. Methodology/Principal Findings Based on new material from the Hauterivian of England and Germany and on abundant material from the Cambridge Greensand Formation, we name a new ophthalmosaurid, Acamptonectes densus gen. et sp. nov. This taxon shares numerous features with Ophthalmosaurus, a genus now restricted to the Callovian–Berriasian interval. Our phylogenetic analysis indicates that Ophthalmosauridae diverged early in its history into two markedly distinct clades, Ophthalmosaurinae and Platypterygiinae, both of which cross the JCB and persist to the late Albian at least. To evaluate the effect of the JCB extinction event on ichthyosaurs, we calculated cladogenesis, extinction, and survival rates for each stage of the Oxfordian–Barremian interval, under different scenarios. The extinction rate during the JCB never surpasses the background extinction rate for the Oxfordian–Barremian interval and the JCB records one of the highest survival rates of the interval. Conclusions/Significance There is currently no evidence that ichthyosaurs were affected by the JCB extinction event, in contrast to many other marine groups. Ophthalmosaurid ichthyosaurs remained diverse from their rapid radiation in the Middle Jurassic to their total extinction at the beginning of the Late Cretaceous

The effect of long term combined yoga practice on the basal metabolic rate of healthy adults

BACKGROUND: Different procedures practiced in yoga have stimulatory or inhibitory effects on the basal metabolic rate when studied acutely. In daily life however, these procedures are usually practiced in combination. The purpose of the present study was to investigate the net change in the basal metabolic rate (BMR) of individuals actively engaging in a combination of yoga practices (asana or yogic postures, meditation and pranayama or breathing exercises) for a minimum period of six months, at a residential yoga education and research center at Bangalore. METHODS: The measured BMR of individuals practicing yoga through a combination of practices was compared with that of control subjects who did not practice yoga but led similar lifestyles. RESULTS: The BMR of the yoga practitioners was significantly lower than that of the non-yoga group, and was lower by about 13 % when adjusted for body weight (P < 0.001). This difference persisted when the groups were stratified by gender; however, the difference in BMR adjusted for body weight was greater in women than men (about 8 and 18% respectively). In addition, the mean BMR of the yoga group was significantly lower than their predicted values, while the mean BMR of non-yoga group was comparable with their predicted values derived from 1985 WHO/FAO/UNU predictive equations. CONCLUSION: This study shows that there is a significantly reduced BMR, probably linked to reduced arousal, with the long term practice of yoga using a combination of stimulatory and inhibitory yogic practices

The stellar halo of the Galaxy

Stellar halos may hold some of the best preserved fossils of the formation history of galaxies. They are a natural product of the merging processes that probably take place during the assembly of a galaxy, and hence may well be the most ubiquitous component of galaxies, independently of their Hubble type. This review focuses on our current understanding of the spatial structure, the kinematics and chemistry of halo stars in the Milky Way. In recent years, we have experienced a change in paradigm thanks to the discovery of large amounts of substructure, especially in the outer halo. I discuss the implications of the currently available observational constraints and fold them into several possible formation scenarios. Unraveling the formation of the Galactic halo will be possible in the near future through a combination of large wide field photometric and spectroscopic surveys, and especially in the era of Gaia.Comment: 46 pages, 16 figures. References updated and some minor changes. Full-resolution version available at http://www.astro.rug.nl/~ahelmi/stellar-halo-review.pd