340 research outputs found

    Offset effect on the S-Bend structure losses and optimization of its size for integrated optics

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    The S-Bend structures are heavily exploited to join optical components. Reducing the power loss caused by the curve is the main objective in the design step of these components. However integrated optical circuits require S-Bend waveguide to be low loss and compact sized. In this paper, we present a contribution to link the curved structure to the straight waveguide by using the simulated bend function available in the Beam propagation tool of the Rsoft commercial software package. Simulation results confirm that this approach allows a reduction of the size of the curved structure with offset with relatively minimum of losses for photonic field

    Kummiluokkatoiminnan arviointi

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    Tämän opinnäytetyön tarkoituksena oli kuvata ja arvioida kummiluokkatoimintaa ja sen vaikutuksia sairaanhoitajaopiskelijan/terveydenhoitajaopiskelijan opintoihin sekä työelämään pääsemiseen ja sopeutumiseen. Tämä opinnäytetyö toteutettiin empiirisenä tutkimuksena. Kummiluokkatoimintaa arvioitiin kyselyn avulla. Kysely tehtiin sähköisenä Webropol-kyselynä. Kysely lähetettiin sähköpostitse 55 hoitoalan opiskelijalle, jotka olivat olleet mukana kummiluokkatoiminnassa. Kyselyyn vastasi yhdeksän opiskelijaa, vastausprosentti oli 16,36 %. Kysely sisälsi sekä avoimia kysymyksiä että monivalintakysymyksiä. Vastausten analysointiin käytettiin sisällönanalyysiä sekä tilastointia. Kyselyn tulokseksi saatiin, että opiskelijat eivät pääosin olleet tyytyväisiä kummiluokkatoimintaan sellaisena kuin se oli toteutunut. Kummiluokkatapaamisia oli ollut liian vähän, eikä niillä ollut vaikutusta työn saantiin. Kuitenkin se toiminta, mitä opiskelijoille oli tarjottu, oli mieleistä. Muutaman opiskelijan mielestä toiminta oli lisännyt halua työskennellä Varsinais-Suomen sairaanhoitopiirissä ja yhden mielestä se oli tehnyt työnhausta helpompaa. Myös vierailukäynnit ja esitykset olivat olleet kiinnostavia, niitä olisi vain pitänyt olla enemmän. Tämän opinnäytetyön tuomaa tietoa voidaan käyttää kummiluokkatoiminnan kehittämiseen, jotta hoitoalan opiskelijat saadaan yhä enemmän sitoutumaan ja kiinnostumaan tulevasta ammatistaan. Saadut tulokset antavat myös lisää syitä kummiluokkatoiminnan jatkamiselle. Jatkotutkimuksina voisi selvittää, miten kummiluokkatoiminta vaikuttaa Turun Yliopistolliseen sairaalaan ja VSSHP:in, eli hyötyykö toiminnasta opiskelijoiden lisäksi myös organisaatio.The purpose of this study was to describe and evaluate the godparent activities and its effects on nursing studies, as well as to work to reach and adjust. This thesis has been implemented by empirical research. Godparent activity was assessed using an inquiry. The inquiry was conducted by Webropol survey. The inquiry was sent by e-mail of 55 nursing students, who had been involved in godparent activities. Nine students responded to the inquiry, the response rate was 16.36%. The inquiry contained both open questions and multiple choice questions. Content analysis and statistics were used for the analysis of the responses. The inquiry led to the result that students are not generally been satisfied with the godparent activities as it had been. Godparent meetings were only few, nor did they have the effect of employment. However, it is low, what activities were offered to students was worthwhile. A few view, the activities had added desire to work in Hospital District of Southwest Finland, and one thought it was done work search easier. Also, visits and information lectures were interesting; they would only have been more. This thesis can be used to develop the godparent activities, to get nursing students to increasingly commit to and interested in their future profession. The information obtained will also provide more reasons to continuation of godparent activities. Possible further studies could figure out how godparent activities affect the Turku University Hospital and in Hospital District of Southwest Finland, to benefit for the students, but also the organization

    The globalizability of temporal discounting

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    Economic inequality is associated with preferences for smaller, immediate gains over larger, delayed ones. Such temporal discounting may feed into rising global inequality, yet it is unclear whether it is a function of choice preferences or norms, or rather the absence of sufficient resources for immediate needs. It is also not clear whether these reflect true differences in choice patterns between income groups. We tested temporal discounting and five intertemporal choice anomalies using local currencies and value standards in 61 countries (N = 13,629). Across a diverse sample, we found consistent, robust rates of choice anomalies. Lower-income groups were not significantly different, but economic inequality and broader financial circumstances were clearly correlated with population choice patterns

    Optical second harmonic generation in Yttrium Aluminum Borate single crystals (theoretical simulation and experiment)

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    Experimental measurements of the second order susceptibilities for the second harmonic generation are reported for YAl3(BO3)4 (YAB) single crystals for the two principal tensor components xyz and yyy. First principles calculation of the linear and nonlinear optical susceptibilities for Yttrium Aluminum Borate YAl3(BO3)4 (YAB) crystal have been carried out within a framework of the full-potential linear augmented plane wave (FP-LAPW) method. Our calculations show a large anisotropy of the linear and nonlinear optical susceptibilities. The observed dependences of the second order susceptibilities for the static frequency limit and for the frequency may be a consequence of different contribution of electron-phonon interactions. The imaginary parts of the second order SHG susceptibility chi_{123}^{(2)}(omega), chi_{112}^{(2)}(omega), chi_{222}^{(2)}(omega), and chi_{213}^{(2)}(omega) are evaluated. We find that the 2(omega) inter-band and intra-band contributions to the real and imaginary parts of chi_{ijk}^{(2)}\l(omega) show opposite signs. The calculated second order susceptibilities are in reasonably good agreement with the experimental measurements.Comment: 16 pages, 11 figure

    Synthesis, X-ray Analysis, and Biological Evaluation of a New Class of Stereopure Lactam-Based HIV-1 Protease Inhibitors

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    In an effort to identify a new class of druglike HIV-1 protease inhibitors, four different stereopure beta-hydroxy gamma-lactam-containing inhibitors have been synthesized, biologically evaluated, and cocrystallized. The impact of the tether length of the central spacer (two or three carbons) was also investigated. A compound with a shorter tether and (3R,4S) absolute configuration exhibited high activity with a K-i of 2.1 nM and an EC50 of 0.64 mu M. Further optimization by decoration of the P1' side chain furnished an even more potent HIV-1 protease inhibitor (K-i = 0.8 nM, EC50 = 0.04 mu M). According to X-ray analysis, the new class of inhibitors did not fully succeed in forming two symmetric hydrogen bonds to the catalytic aspartates. The crystal structures of the complexes further explain the difference in potency between the shorter inhibitors (two-carbon spacer) and the longer inhibitors (three-carbon spacer)

    Developing optimal input design strategies in cancer systems biology with applications to microfluidic device engineering

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    <p>Abstract</p> <p>Background</p> <p>Mechanistic models are becoming more and more popular in Systems Biology; identification and control of models underlying biochemical pathways of interest in oncology is a primary goal in this field. Unfortunately the scarce availability of data still limits our understanding of the intrinsic characteristics of complex pathologies like cancer: acquiring information for a system understanding of complex reaction networks is time consuming and expensive. Stimulus response experiments (SRE) have been used to gain a deeper insight into the details of biochemical mechanisms underlying cell life and functioning. Optimisation of the input time-profile, however, still remains a major area of research due to the complexity of the problem and its relevance for the task of information retrieval in systems biology-related experiments.</p> <p>Results</p> <p>We have addressed the problem of quantifying the information associated to an experiment using the Fisher Information Matrix and we have proposed an optimal experimental design strategy based on evolutionary algorithm to cope with the problem of information gathering in Systems Biology. On the basis of the theoretical results obtained in the field of control systems theory, we have studied the dynamical properties of the signals to be used in cell stimulation. The results of this study have been used to develop a microfluidic device for the automation of the process of cell stimulation for system identification.</p> <p>Conclusion</p> <p>We have applied the proposed approach to the Epidermal Growth Factor Receptor pathway and we observed that it minimises the amount of parametric uncertainty associated to the identified model. A statistical framework based on Monte-Carlo estimations of the uncertainty ellipsoid confirmed the superiority of optimally designed experiments over canonical inputs. The proposed approach can be easily extended to multiobjective formulations that can also take advantage of identifiability analysis. Moreover, the availability of fully automated microfluidic platforms explicitly developed for the task of biochemical model identification will hopefully reduce the effects of the 'data rich-data poor' paradox in Systems Biology.</p

    Chemical Approaches To Perturb, Profile, and Perceive Glycans

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    Glycosylation is an essential form of post-translational modification that regulates intracellular and extracellular processes. Regrettably, conventional biochemical and genetic methods often fall short for the study of glycans, because their structures are often not precisely defined at the genetic level. To address this deficiency, chemists have developed technologies to perturb glycan biosynthesis, profile their presentation at the systems level, and perceive their spatial distribution. These tools have identified potential disease biomarkers and ways to monitor dynamic changes to the glycome in living organisms. Still, glycosylation remains the underexplored frontier of many biological systems. In this Account, we focus on research in our laboratory that seeks to transform the study of glycan function from a challenge to routine practice
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