The radiated fields of the fundamental mode of photonic crystal fibers

The six-fold rotational symmetry of photonic crystal fibers has important manifestations in the radiated fields in terms of i) a focusing phenomena at a finite distance from the end-facet and ii) the formation of low-intensity satellite peaks in the asymptotic far field. For our study, we employ a surface equivalence principle which allows us to rigorously calculate radiated fields starting from fully-vectorial simulations of the near field. Our simulations show that the focusing is maximal at a characteristic distance from the end-facet. For large-mode area fibers the typical distance is of the order 10 Lambda with Lambda being the pitch of the triangular air-hole lattice of the photonic crystal fiber.Comment: 6 pages including 4 figures. Accepted for Opt. Expres

Metabolite biosensors for cell factory development

Through synergy with natural sciences and engineering disciplines, biotechnology has\ua0become a broad, interdisciplinary, scientific field with many applications. One such\ua0application is the sustainable production of industrially relevant products using living\ua0systems such as microorganisms. Transforming microorganisms to cell factories is, however,\ua0a labour-intensive and cost-ineffective process, requiring many years of extensive\ua0research. Several fields together known as systems metabolic engineering, including\ua0synthetic biology, have greatly facilitated the process of customizing microorganisms\ua0to benefit human interests. Among several emerging tools are metabolite biosensors,\ua0which can be employed in high-throughput screening endeavours for identifying productive\ua0cells and in dynamic pathway regulation for optimizing metabolic systems.\ua0Developing and engineering metabolite biosensors to fit a certain application is, however,\ua0challenging.This thesis focuses on different aspects of utilizing and engineering metabolite-responsive\ua0transcription factor-based biosensors for facilitating the development of\ua0Saccharomyces cerevisiae as a cell factory. To that end, we improved the dynamic\ua0range of a malonyl-CoA-responsive biosensor by i) evaluating different binding site\ua0locations of the bacterial transcription factor FapR within different yeast promoters\ua0and by ii) using a chimeric transcription factor based on a native repressor system\ua0from S. cerevisiae. Furthermore, we suggest the possibility of using the CRISPR (Clustered\ua0Regulatory Interspaced Short Palindromic Repeats)/Cas9 system to facilitate\ua0biosensor development by guiding binding site positioning. We also employed an acyl-CoA-responsive biosensor based on the bacterial transcription factor FadR to screen for\ua0genes boosting the fatty acyl-CoA levels, which are precursors for industrially relevant\ua0compounds such as fatty alcohols. The possibility of developing fatty acid-responsive\ua0biosensors based on other transcription factors, including the endogenous transcription\ua0factor Mga2, has also been addressed. Finally, we looked into the potential of\ua0developing an alkane-responsive biosensor based on a system from Yarrowia lipolytica.\ua0Overall, this thesis provides answers, discussions and potential future directions on\ua0using and engineering metabolite biosensors for cell factory development

Making sense of text: artificial intelligence-enabled content analysis

Purpose: The purpose of this paper is to introduce, apply and compare how artificial intelligence (AI), and specifically the IBM Watson system, can be used for content analysis in marketing research relative to manual and computer-aided (non-AI) approaches to content analysis. Design/methodology/approach: To illustrate the use of AI-enabled content analysis, this paper examines the text of leadership speeches, content related to organizational brand. The process and results of using AI are compared to manual and computer-aided approaches by using three performance factors for content analysis: reliability, validity and efficiency. Findings: Relative to manual and computer-aided approaches, AI-enabled content analysis provides clear advantages with high reliability, high validity and moderate efficiency. Research limitations/implications: This paper offers three contributions. First, it highlights the continued importance of the content analysis research method, particularly with the explosive growth of natural language-based user-generated content. Second, it provides a road map of how to use AI-enabled content analysis. Third, it applies and compares AI-enabled content analysis to manual and computer-aided, using leadership speeches. Practical implications: For each of the three approaches, nine steps are outlined and described to allow for replicability of this study. The advantages and disadvantages of using AI for content analysis are discussed. Together these are intended to motivate and guide researchers to apply and develop AI-enabled content analysis for research in marketing and other disciplines. Originality/value: To the best of the authors' knowledge, this paper is among the first to introduce, apply and compare how AI can be used for content analysis

Does co-expression of Yarrowia lipolytica genes encoding Yas1p, Yas2p and Yas3p make a potential alkane-responsive biosensor in Saccharomyces cerevisiae?

Alkane-based biofuels are desirable to produce at a commercial scale as these have properties similar to current petroleum-derived transportation fuels. Rationally engineering microorganisms to produce a desirable compound, such as alkanes, is, however, challenging. Metabolic engineers are therefore increasingly implementing evolutionary engineering approaches combined with high-throughput screening tools, including metabolite biosensors, to identify productive cells. Engineering Saccharomyces cerevisiae to produce alkanes could be facilitated by using an alkane-responsive biosensor, which can potentially be developed from the native alkane-sensing system in Yarrowia lipolytica, a well-known alkaneassimilating yeast. This putative alkane-sensing system is, at least, based on three different transcription factors (TFs) named Yas1p, Yas2p and Yas3p. Although this system is not fully elucidated in Y. lipolytica, we were interested in evaluating the possibility of translating this system into an alkane-responsive biosensor in S. cerevisiae. We evaluated the alkanesensing system in S. cerevisiae by developing one sensor based on the native Y. lipolytica ALK1 promoter and one sensor based on the native S. cerevisiae CYC1 promoter. In both systems, we found that the TFs Yas1p, Yas2p and Yas3p do not seem to act in the same way as these have been reported to do in their native host. Additional analysis of the TFs suggests that more knowledge regarding their mechanism is needed before a potential alkane-responsive sensor based on the Y. lipolytica system can be established in S. cerevisiae. Copyright

Propagation of Light in Photonic Crystal Fibre Devices

We describe a semi-analytical approach for three-dimensional analysis of photonic crystal fibre devices. The approach relies on modal transmission-line theory. We offer two examples illustrating the utilization of this approach in photonic crystal fibres: the verification of the coupling action in a photonic crystal fibre coupler and the modal reflectivity in a photonic crystal fibre distributed Bragg reflector.Comment: 15 pages including 7 figures. Accepted for J. Opt. A: Pure Appl. Op

The effect of posture in premature infants on the arterial oxygen saturation, fraction of inspired oxygen and abdominal distension

Background: Putting infants in a posture that reduces oxygen requirement and the complications of the continuous positive airway pressure method is very important. This study aimed at examining the effect of the posture on the arterial oxygen saturation, fraction of inspired oxygen (FIO2) and abdominal distension in premature infants with the respiratory distress syndrome under nasal continuous positive airway pressure. Materials and Methods: In this clinical trial study, 41 premature infants were selected by the simple random sampling and one-group before-after design. The amounts of arterial oxygen saturation, FIO2 and abdominal distension in supine and prone positions were recorded in a data-collection form. Results: There was a significant difference between the mean FIO2 and between the mean abdominal circumference in the prone and supine positions (P=0.022, P<0.001, respectively). There was no significant difference in the mean of arterial oxygen saturation between the two positions (P=0.749). Conclusion: According to the results of the present study, the neonates’ abdominal distension and FIO2 decreased in the prone position. Thus, this supportive, free of charge and effective method can be recommended for these neonates

Rational gRNA design based on transcription factor binding data

The clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 system has become a standard tool in many genome engineering endeavors. The endonuclease-deficient version of Cas9 (dCas9) is also a powerful programmable tool for gene regulation. In this study, we made use of Saccharomyces cerevisiae transcription factor (TF) binding data to obtain a better understanding of the interplay between TF binding and binding of dCas9 fused to an activator domain, VPR. More specifically, we targeted dCas9-VPR toward binding sites of Gcr1-Gcr2 and Tye7 present in several promoters of genes encoding enzymes engaged in the central carbon metabolism. From our data, we observed an upregulation of gene expression when dCas9-VPR was targeted next to a TF binding motif, whereas a downregulation or no change was observed when dCas9 was bound on a TF motif. This suggests a steric competition between dCas9 and the specific TF. Integrating TF binding data, therefore, proved to be useful for designing guide RNAs for CRISPR interference or CRISPR activation applications

Local correlations in the 1D Bose gas from a scaling limit of the XXZ chain

We consider the K-body local correlations in the (repulsive) 1D Bose gas for general K, both at finite size and in the thermodynamic limit. Concerning the latter we develop a multiple integral formula which applies for arbitrary states of the system with a smooth distribution of Bethe roots, including the ground state and finite temperature Gibbs-states. In the cases K<=4 we perform the explicit factorization of the multiple integral. In the case of K=3 we obtain the recent result of Kormos et.al., whereas our formula for K=4 is new. Numerical results are presented as well.Comment: 23 pages, 2 figures, v2: minor modifications and references adde

Travelling with a Stoma: A literature Review

This document is the Accepted Manuscript version of a Published Work that appeared in final form in Gastrointestinal Nursing, copyright © MA Healthcare, after peer review and technical editing by the publisher. To access the final edited and published work see http://www.magonlinelibrary.com/toc/gasn/currentGiven the daily challenges that unfamiliar environments, food and culture bring, many ostomates find the prospect of travelling with a stoma stressful. Yet with good advice, international travel can be enjoyed, whether experienced for leisure or work purposes. To practice safely, nurses require knowledge of research evidence, combined with a wealth of practical knowledge, derived from patient experience. This article examines how these types of knowledge can be brought together to ensure that people with a stoma are able to anticipate travel in a more positive way.Peer reviewedFinal Accepted Versio