Physicochemical study of spiropyran-terthiophene derivatives: photochemistry and thermodynamics

The photochemistry and thermodynamics of two terthiophene (TTh) derivatives bearing benzospiropyran (BSP) moieties, 1-(3,3’’-dimethylindoline-6’-nitrobenzospiropyranyl)-2-ethyl 4,4’’-didecyloxy-2,2’:5’,2’’-terthiophene-3’-acetate (BSP-2) and 1-(3,3’’-dimethylindoline-6’-nitrobenzospiropyranyl)-2-10 ethyl 4,4’’-didecyloxy-2,2’:5’,2’’-terthiophene-3’-carboxylate (BSP-3), differing only by a single methylene spacer unit, have been studied. The kinetics of photogeneration of the equivalent merocyanine (MC) isomers (MC-2 and MC-3, respectively), the isomerisation properties of MC-2 and MC-3, and the thermodynamic parameters have been studied in cetonitrile, and compared to the parent, non-TThfunctionalised, benzospiropyran derivative, BSP-1. Despite the close structural similarity of BSP-2 and 15 BSP-3, their physicochemical properties were found to differ significantly; examples include activation energies (Ea(MC-2) = 75.05 KJ mol-1, Ea(MC-3) = 100.39 kJ mol-1) and entropies of activation (S‡ MC-2 = - 43.38 J K-1 mol-1, S‡ MC-3 = 37.78 J K-1 mol-1) for the thermal relaxation from MC to BSP, with the MC-3 value much closer to the unmodified MC-1 value (46.48 J K -1 mol-1) for this latter quantity. The thermal relaxation kinetics and solvatochromic behaviour of the derivatives in a range of solvents of 20 differing polarity (ethanol, dichloromethane, acetone, toluene and diethyl ether) are also presented. Differences in the estimated values of these thermodynamic and kinetic parameters are discussed with reference to the molecular structure of the derivatives

Spiropyran modified micro-fluidic chip channels as photonically controlled self-indicating system for metal ion accumulation and release

In this paper, we show how through integrating the beneficial characteristics of micro-fluidic devices and spiropyrans dyes, a simple and very innovative chip configured as an on-line photonically controlled self-indicating system for metal ion accumulation and release can be realised. The micro-fluidic device consists of five independent 94 μm depth, 150 μm width channels fabricated in polydimethylsiloxane. The spiropyran 1’-(3-carboxypropyl)-3,3’-dimethyl-6-nitrospiro-1-benzopyran-2,2’-indoline is immobilised by physical adsorption into a polydimethylsiloxane matrix and covalently on the ozone plasma activated polydimehylsiloxane micro-channel walls. When the colourless, inactive, spiropyran coating absorbs UV light it switches to the highly coloured merocyanine form, which also has an active binding site for certain metal ions. Therefore metal ion uptake can be triggered using UV light and subsequently reversed on demand by shining white light on the coloured complex, which regenerates the inactive spiropyran form, and releases the metal ion. When stock solutions of several metal ions (Ca2+, Zn2+, Hg2+, Cu2+, Co2+) are pumped independently through the five channels, different optical responses were observed for each metal, and the platform can therefore be regarded as a micro-structured device for online self-indicating metal ion complexation, accumulation and release

Designer molecular probes for phosphonium ionic liquids

Investigations into the extent of structuring present in phosphonium based ionic liquids (ILs) have been carried out using photochromic molecular probes. Three spiropyran derivatives containing hydroxyl (BSP-1), carboxylic acid (BSP-2) and aliphatic chain (C14H29) (BSP-3) functional groups have been analysed in a range of phosphonium based ionic liquids and their subsequent physico-chemical interactions were reported. It is believed that the functional groups locate the probe molecules into specific regions based upon the interaction of the functional groups with particular and defined regions of the ionic liquid. This structuring results in thermodynamic, kinetic and solvatochromic parameters that are not predictable from classical solvent models. BSP-1 and BSP-2 exhibit generally negative entropies of activation ranging from -50 J K-1 mol-1 to -90 J K-1 mol-1 implying relatively low solvent–solute interactions and possible anion interactions with IL polar functional groups. Higher than expected activation energies of 60 kJ mol-1 to 100 kJ mol-1 obtained for polar probes maybe be due to IL functional groups competing with the charged sites of the merocyanine (MC) isomer thus reducing MC stabilisation effects. Differences in thermal relaxation rate constants (2.5 × 10-3 s-1 in BSP-1 and 3 × 10-4 s-1 in BSP-2 in [P6,6,6,14][dbsa]) imply that while the polar probe systems are primarily located in polar/charged regions, each probe experiences slightly differing polar domains. BSP-3 entropies of activation are positive and between 30 J K-1 mol-1 to 66 J K-1 mol-1. The association of the non-polar functional group is believed to locate the spiropyran moiety in the interfacial polar and non-polar regions. The thermal relaxation of the MC form causes solvent reorientation to accommodate the molecule as it reverts to its closed form. Slow thermal relaxation rate constants were obserevd in contrast to high activation energies (5 × 10-4 s-1 and 111.91 kJ mol-1 respectively, for BSP-3 in [P6,6,6,14][dbsa]). This may be due to steric effects arising from proposed nano-cavity formation by the alkyl chains in phosphonium based ILs

Primary skin fibroblasts as a model of Parkinson's disease

Parkinson's disease is the second most frequent neurodegenerative disorder. While most cases occur sporadic mutations in a growing number of genes including Parkin (PARK2) and PINK1 (PARK6) have been associated with the disease. Different animal models and cell models like patient skin fibroblasts and recombinant cell lines can be used as model systems for Parkinson's disease. Skin fibroblasts present a system with defined mutations and the cumulative cellular damage of the patients. PINK1 and Parkin genes show relevant expression levels in human fibroblasts and since both genes participate in stress response pathways, we believe fibroblasts advantageous in order to assess, e.g. the effect of stressors. Furthermore, since a bioenergetic deficit underlies early stage Parkinson's disease, while atrophy underlies later stages, the use of primary cells seems preferable over the use of tumor cell lines. The new option to use fibroblast-derived induced pluripotent stem cells redifferentiated into dopaminergic neurons is an additional benefit. However, the use of fibroblast has also some drawbacks. We have investigated PARK6 fibroblasts and they mirror closely the respiratory alterations, the expression profiles, the mitochondrial dynamics pathology and the vulnerability to proteasomal stress that has been documented in other model systems. Fibroblasts from patients with PARK2, PARK6, idiopathic Parkinson's disease, Alzheimer's disease, and spinocerebellar ataxia type 2 demonstrated a distinct and unique mRNA expression pattern of key genes in neurodegeneration. Thus, primary skin fibroblasts are a useful Parkinson's disease model, able to serve as a complement to animal mutants, transformed cell lines and patient tissues

Mazar\u27s Modified Chronology: The Preservation of Solomonic Possibilities

In the polarized, post-enlightenment world of biblical studies, there is a need for measured approaches to scholarly debate which hold ample room for all possible realities. The timeline of the Solomonic gates at Tel-Megiddo has been debated for years, with Yiguel Yadin\u27s conventional foundation coming into conflict with newer, more critical approaches such as Isreal Finkelstein\u27s Low Chronology . In this paper, it will be argued that in the polarized wreckage, Amihai Mazar and his Modified Conventional Chronology preserve the necessary lack of conclusion that current ambiguities call for. His work demonstrates that many explicit conclusions which polarize the debate are hypotheses at best, and should be approached with caution

Advisor Networks and Referrals for Improved Trust Modelling in Multi-Agent Systems

This thesis relates to the usage of trust modelling in multi-agent systems - environments in which there are interacting software agents representing various users (for example, buyers and sellers exchanging products and services in an electronic marketplace). In such applications, trust modelling may be crucial to allow one group of agents (in the e-commerce scenario, buyers) to make effective decisions about which other agents (i.e., sellers) are the most appropriate partners. A number of existing multi-agent trust models have been proposed in the literature to help buyers accurately select the most trustworthy sellers. Our contribution is to propose several modifications that can be applied to existing probabilistic multi-agent trust models. First, we examine how the accuracy of the model can be improved by limiting the network to a portion of the population consisting of the most trustworthy agents, such that the less trustworthy contributions of the remaining agents can be ignored. In particular, we explore how this can be accomplished by either setting a maximum size for a buyer's advisor network or setting a minimum trustworthiness threshold for agents to be accepted into that advisor network, and develop methods for appropriately selecting the values to limit the network size. We demonstrate that for two models, both the Personalized Trust Model (PTM) developed by Zhang as well as TRAVOS, these approaches will yield significant improvements to the accuracy of the trust model, as opposed to using an unrestricted advisor network. Our final proposed modification is to use an advisor referral system in combination with one of the network-limiting approaches. This would ensure that if a particular agent within the advisor network had not met a specified level of experience with the seller under consideration, it could be replaced by another agent that had greater experience with that seller, which should in turn allow for a more accurate modelling of the seller's trustworthiness. We present a particular approach for replacing advisors, and show that this will yield additional improvements in trust-modelling accuracy with both PTM and TRAVOS, especially if the limiting step were such that it would yield a very small advisor network. We believe that these techniques will be very useful for trust researchers seeking to improve the accuracy of their own trust models, and to that end we explain how other researchers could apply these modifications themselves, in order to identify the optimal parameters for their usage. We discuss as well the value of our proposals for identifying an "optimal" size for a social network, and the use of referral systems, for researchers in other areas of artificial intelligence

El ir y venir de la aviación en Colombia : un acercamiento a la historia de la aviación colombiana y a la de aquellos a quienes les confiamos nuestras vidas a la hora de volar

Documental que relata la historia de la aviación colombiana, contada directamente por aquellos que se encuentran detrás de la máquina y que han vivido distintos sucesos a lo largo de su carrera. Desde los inicios de la aviación en Colombia, se inicia con SCADTA, para luego continuar con Avianca hasta la fecha. Al finalizar se hace un paralelo entre los pilotos de distintas edades y generaciones para darnos cuenta del cambio en los últimos años.Documentary film that shows us the story of aviation in Colombia. This story is told by those who stand directly behind the machine and who have lived different events during their lives. From the beginning of aviation in Colombia. Starts with SCADTA and then cotinues with Avianca until now. At the end, a parallel is made between yound and old pilots to realice the change in aviation during the last yearsComunicador (a) SocialPregrad

Genomic Phenotyping by Barcode Sequencing Broadly Distinguishes between Alkylating Agents, Oxidizing Agents, and Non-Genotoxic Agents, and Reveals a Role for Aromatic Amino Acids in Cellular Recovery after Quinone Exposure

Toxicity screening of compounds provides a means to identify compounds harmful for human health and the environment. Here, we further develop the technique of genomic phenotyping to improve throughput while maintaining specificity. We exposed cells to eight different compounds that rely on different modes of action: four genotoxic alkylating (methyl methanesulfonate (MMS), N-Methyl-N-nitrosourea (MNU), N,N′-bis(2-chloroethyl)-N-nitroso-urea (BCNU), N-ethylnitrosourea (ENU)), two oxidizing (2-methylnaphthalene-1,4-dione (menadione, MEN), benzene-1,4-diol (hydroquinone, HYQ)), and two non-genotoxic (methyl carbamate (MC) and dimethyl sulfoxide (DMSO)) compounds. A library of S. cerevisiae 4,852 deletion strains, each identifiable by a unique genetic ‘barcode’, were grown in competition; at different time points the ratio between the strains was assessed by quantitative high throughput ‘barcode’ sequencing. The method was validated by comparison to previous genomic phenotyping studies and 90% of the strains identified as MMS-sensitive here were also identified as MMS-sensitive in a much lower throughput solid agar screen. The data provide profiles of proteins and pathways needed for recovery after both genotoxic and non-genotoxic compounds. In addition, a novel role for aromatic amino acids in the recovery after treatment with oxidizing agents was suggested. The role of aromatic acids was further validated; the quinone subgroup of oxidizing agents were extremely toxic in cells where tryptophan biosynthesis was compromised.Unilever (Firm)National Cancer Institute (U.S.) (R01-CA055042 (now R01-ES022872))Massachusetts Institute of Technology. Center for Environmental Health Sciences (Grant NIEHS P30-ES002109

Methods of studying the cardiovascular system in students of a sports university in the process of recreational rest

Background and Study Aim. The aim of the study is to develop a methodology for examining the cardiovascular system in students with different levels of physical activity. Materials and Methods. Students of the Academy of Physical Culture (Kharkiv, Ukraine) took part in the study: 3-4 year full-time and part-time students. A scheme for examining the cardiovascular system in this category of students has been drawn up. A survey was conducted during practical exercises on physical recreation during the years 2006 – 2011. The research methods were taken as the basis: circulatory organs; patients with diseases of the cardiovascular system; circulatory systems. Results. The definitions of recreation are considered. Its types and functions are shown. Directions for assessing the level of the functional state of the cardiovascular system in students with a high level of physical activity are given. A plan-scheme for studying this system has been drawn up. The peculiarity of the system is to take into account the specifics of the future profession. Assessment of the functional state of the student's cardiovascular system is carried out in a complex manner. Conclusions. It is necessary to take into account the anamnesis of the entire life of the student. It is necessary to apply sports, clinical, instrumental, laboratory, biochemical research methods. The results of functional trials and tests should be taken into account. Functional tests and tests should reflect the response of the cardiovascular system to the physical load and determine the overall physical performance

Search for vector-like T quarks decaying to top quarks and Higgs bosons in the all-hadronic channel using jet substructure

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