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The review addresses features of special interest concerning two classes of functionalized semiconducting polymers: poly(aryleneethynylene)s (PAEs) bearing biomolecules as chiral nonracemic pendant groups and poly(phenylenevinylene)s (PPVs), which are fluorinated in various positions of the repeating units. Molecular design and choice of specific substituents, synthetic protocols, and the effect of functionalization on properties of the polymers both in solution and in the solid state are discussed.

A conjugated alternating copolymer containing norbornadiene and bis(ethynylene)phenylene units was prepared by the Cassar-Heck-Sonogashira cross-coupling reaction. Its electroluminescence was tested in a device, and its fluorescence colour could be tuned by light-induced norbornadiene-quadricyclane isomerization.

Over the past decade synthetic melanins, melanin-like polymers and melanin-based copolymers have been the focus of growing attention as soft biocompatible functional materials for engineering high performance, low cost optoelectronic devices, such as memory devices, light emitting diodes and field effect transistors. The unique combination of physicochemical properties of melanins, such as broad band absorption in the UV-visible range, intrinsic free radical character, water-dependent hybrid ionic-electronic conductor behaviour and excellent biocompatibility, have inspired use of melanic polymers as valuable functional materials for organic bioelectronics. However, several gaps and issues still hinder rapid progress of melanin-based organic electronics and bioelectronics, including in particular the limited contribution of electronic conductivity and current decay with time under biasing. The aim of this paper is to provide an overview of the structural and optoelectronic properties of melanins and to bring to focus current gaps and challenges in the development of melanin-based materials for bioelectronics. Starting from commercial samples, the paper surveys different melanin-type materials with special emphasis on the potential of polydopamine (pDA), a highly adhesive mussel-inspired melanin-type platform, for incorporation in optoelectronic devices. Simple chemical tailoring procedures for engineering pDA-based n-type polymers and photoresponsive materials for photocapacitive sensors are eventually illustrated.

This paper presents algorithms for identifying machined parts in a database that are similar to a given query part based on machining features. In this paper we only consider parts that are machined on 3-axis machining centers. We utilize reduced feature vectors consisting of machining feature access directions, feature types, feature volumes, feature dimensional tolerances and feature group cardinality as a basis for assessing shape similarity. We have defined a distance function between two sets of reduced feature vectors to assess the similarity between them from the machining effort point of view. To assess the similarity between the two parts, one set of reduced feature vectors is transformed in space using rigid body transformations with respect to the other set such that the distance between them is minimized. The distance between the two sets of aligned reduced feature vectors is used as a measure of similarity between the two parts. The existing machined parts are rank ordered based on the value of the distance with respect to the query part. The cost of previously machined parts that have a very small distance from the query part can be used as a basis for estimating the cost of machining the new part.

In certain shape similarity assessment applications, type, locations, and orientations of faces in boundary representations plays a key role in determining similarity between two parts. This paper describes an algorithm that assesses similarity between two parts by explicitly aligning their faces and hence accounts for these face attributes. The approach involves extracting attributed applied vectors from the face information of parts and aligning the two sets of attributed applied vectors using rigid body transformations. The algorithm uses a customizable distance function to align attributed applied vectors. The distance between two aligned attributed applied vector sets is used as a measure of similarity between two parts. This paper also presents computational results to illustrate discrimination capability of the algorithm.

The popularity of 3D CAD systems is resulting in large assembly and part databases being created by product development organizations. Over the last few years several content-based techniques have emerged to search these databases. Ability to perform content-based searches on CAD databases is expected to help the designers and manufacturing engineers in many different ways. Representative examples include part-family formation, redesign suggestion generation, supplier selection, cost estimation, tooling design, machine selection, stock selection, and design reuse. This paper covers the following three topics. First, it presents an overview of different types of part search techniques. Second, it presents an overview of the different aspects of assembly search techniques. Finally, it identifies the open challenges in these areas and outlines future research directions.

A copolymer of 2,3,5,6-tetrafluoro-1,4-phenylenevinylene and 2,5-dioctyloxy-1,4-phenylenevinylene [co(TFPV-DOPV)], containing more than 60% of tetrafluorophenylenevinylene monomeric units, was synthesized by the Stille cross-coupling reaction. Its linear and nonlinear optical properties were investigated. Linear absorption and photoluminescence measurements performed on thin films and solution indicate interchain migration upon excitation. A copolymer of 2,3,5,6-tetrafluoro-1,4-phenylenevinylene and 2,5-dioctyloxy-1,4-phenylenevinylene [co(TFPV-DOPV)], containing more than 60% of tetrafluorophenylenevinylene monomeric units, was synthesized by the Stille cross-coupling reaction. Its linear and nonlinear optical properties were investigated. Linear absorption and photoluminescence measurements performed on thin films and solution indicate interchain migration upon excitation. The Z-scan technique was used to evaluate the third-order nonlinear susceptibility. A very high refractive nonlinearity was measured with a value one order of magnitude larger than that of the corresponding dialkoxy-substituted homopolymer.

Shape similarity assessment is a fundamental geometric reasoning problem that finds application in several different product design and manufacturing applications. A computationally efficient way to assess shape similarity is to first abstract 3D object shapes into shape signatures and use shape signatures to perform similarity assessment. Several different types of shape signatures have been developed in the past. This paper provides a survey of existing algorithms for computing and comparing shape signatures. Our survey consists of a description of the desired properties of shape signatures, a scheme for classifying different types of shape signatures, and descriptions of representative algorithms for computing and comparing shape signatures. This survey concludes by identifying directions for future research. 1 Corresponding Author

Ring the changes: Experimental Raman spectra of fluorinated and non-fluorinated polyphenylenevinylenes are assigned according to quantum chemical calculations for oligomer model systems [picture: see text]. Characteristic differences in the spectra can be traced back to strong inter-ring distortion of the fluorinated compounds.The Raman spectrum of poly{2-methoxy-5-[(2-ethylhexyl)oxy]-1,4-phenylenedifluorovinylene} (MEH-PPDFV) is reported and compared with that of a well-known non-fluorinated reference polymer, namely poly{2-methoxy-5-[(2-ethylhexyl)oxy]-1,4-phenylenevinylene} (MEH-PPV). The Raman spectra of both polymers are assigned on the basis of density functional theory calculations of the corresponding oligomers. The main differences between vinylene fluorinated and non-fluorinated structures deal with the intensity, frequency shift and broadening of C--C vinylene stretching. Additional differences concern the relative intensities of C-C phenylene and vinylene stretching as well as the deformation modes in the range 1250-1350 cm(-1). It is shown that these effects are due to the larger distortion from planarity of the fluorinated polymer, compared with the non-fluorinated counterpart, induced by repulsive interactions between the fluorine atoms on the vinylene units and the oxygen atoms of the alkoxy groups on the aromatic rings.

A method is proposed to study protein-ligand binding in a system governed by specific and non-specific interactions. Strong associations lead to narrow distributions in the proteins configuration space; weak and ultra-weak associations lead instead to broader distributions, a manifestation of non-specific, sparsely-populated binding modes with multiple interfaces. The method is based on the notion that a discrete set of preferential first-encounter modes are metastable states from which stable (pre-relaxation) complexes at equilibrium evolve. The method can be used to explore alternative pathways of complexation with statistical significance and can be integrated into a general algorithm to study protein interaction networks. The method is applied to a peptide-protein complex. The peptide adopts several low-population conformers and binds in a variety of modes with a broad range of affinities. The system is thus well suited to analyze general features of binding, including conformational selection, multiplicity of binding modes, and nonspecific interactions, and to illustrate how the method can be applied to study these problems systematically. The equilibrium distributions can be used to generate biasing functions for simulations of multiprotein systems from which bulk thermodynamic quantities can be calculated.

Background Selective imaging of lysosomes by fluorescence microscopy using specific fluorescent probes allows the study of biological processes and it is potentially useful also for diagnosis. Lysosomes are involved in numerous physiological processes, such as bone and tissue remodeling, plasma membrane repair, and cholesterol homeostasis, along with cell death and cell signaling. Despite the great number of dyes available today on the market, the search for new fluorescent dyes easily up-taken by cells, biocompatible and bearing bright and long-lasting fluorescence is still a priority. Methods Two thiophene-based fluorescent dyes, TC1 and TC2, were synthetized as lysosome-specific probes. Results The new dyes showed high selectivity for fluorescent staining and imaging of lysosomes and disclosed high photostability, low toxicity and pH insensitivity in the range 2–10. Conclusions The TC dyes exhibited high co-localization coefficients (> 95%) and moderate quantum yields. They showed high biocompatibility and long-term retention, important features for biological applications. General significance The results of the present work disclose a new class of organic dyes with potential wide applications as specific and efficient lysosome probes in the study of various biological processes.

Benzofulvenes-based monomers have been synthesized for the first time and have been polymerized by means of electrochemical methods onto different electrodic materials. Morphological investigation has been performed by using SEM; electrical and optical properties have been studied by means of both cyclic voltammetry, optical absorption and spectroelectrochemical techniques. Finally, solid state electrochromic devices have been fabricated. They have displayed high optical contrast.

Colloidal white emitting nanostructures were successfully fabricated by covalently binding a blue emitting oligofluorene at the surface of silica beads, that incorporate orange luminescent colloidal CdSe@ZnS quantum dots (QDs). White light was achieved by carefully tuning the size of the QDs to complementarily match the emission color of the blue fluorophore and taking into account the delicate balance between the emission of the QDs in the core of the silica beads and the amount of the organic dye bound to the silica surface. The proposed approach is highly versatile as it can be extended to the fabrication of a variety of luminescent hybrid nano-objects, playing with the complementarity of the emission color of the inorganic and organic fluorophores at the nanoscale. This journal is © the Partner Organisations 2014.

A white emitting copolymer with the polyphenylenevinylene (PPV) structure is obtained via the Stille cross-coupling reaction. Substitution of hydrogen atoms with fluorine atoms on the vinylene units of poly(1,4-dialkoxyphenylenevinylene) shifts the emission from orange-red to blue. White emission is obtained by combining dialkoxyphenylenedifluorovinylene and dialkoxyphenylenevinylene units in proper ratio. The two complementary emitters are obtained separately by Stille polymerization reaction. Then, the two reaction mixtures are combined without purification in different ratios and further reacted in similar experimental conditions. A white luminescent material is obtained using 99/1 mixing ratio. OLED devices fabricated with this copolymer shows near-white emission with CIE (0.30, 0.40) and excellent stability in the range 10–200 cd/m 2 .

The electrical transport across a biomimetic interface made up of spin coated melanin layers on nanotextured silicon surfaces with different texturing features and wetting properties is discussed. Nanotexturing allows, under certain conditions, the melanin to anchor better on a hydrophobic silicon surface, overcoming the hydrophilic melanin–hydrophobic silicon interface issue. The feature of the electrical signal transduction across such a structure was studied by impedance spectroscopy and found to be influenced by the nano-texturing chemistry and surface morphology. The effects of a voltage pulse, as external stimulus modifying the electrical transport mechanisms, and retention of the subsequently achieved carrier transport conditions have been elucidated. The results suggest a possible exploiting of this circuit element for bio and environmental molecules’ sensing.

Inspired by the powerful photosensitizing properties of the red hair pigments pheomelanins, a photoresponsive cysteine-containing variant of the adhesive biopolymer polydopamine (pDA) is developed via oxidative copolymerization of dopamine (DA) and 5-S-cysteinyldopamine (CDA) in variable ratios. Chemical and spectral analysis indicate the presence of benzothiazole/benzothiazine units akin to those of pheomelanins. p(DA/CDA) copolymers display impedance properties similar to those of biological materials and a marked photoimpedance response to light stimuli. The use of the p(DA/CDA) copolymer to implement a solution-processed hybrid photocapacitive/resistive metalinsulator- semiconductor (MIS) device disclosed herein is the fi rst example of technological exploitation of photoactive, red-hair-inspired biomaterials as soft enhancement layer for silicon in an optoelectronic device. The bio-inspired materials described herein may provide the active component of new hybrid photocapacitive sensors with a chemically tunable response to visible light.

Background and aim oft he work In patìents with disseminated endometrial carcinoma, doxorubicin is used as a single agent or in combination therapy. We have carried out a phase II clinical trial of liposomal doxorubicin in first-line therapy of women with disseminated endometrial carcinoma. Methods: Betwecn September 2001 and May 2003, 22 patìents with histologically confirmed disseminated endometrial carci¬noma, were enrolled in this study. Eleven patìents had been previously treated with radiatìon, none of them had been treated with chemotherapy. Liposomal doxorubicin (40 mg/m2) was intravenously administered at 4 week intervals until toxicity or progression. Results: The most common adverse events were fatigue, ane¬mia, pain, and dermatologic toxicity (EPP). Eight patìents (36%) achieved a tumor regression (Complete response, CR 3; Partial response, PR 5), ten (46%) maintained stable disease, and four (18%) experienced in-creasing disease. Conclusion: Liposomal doxorubicin has a lower cardiologie toxicity than doxorubicin with a similar response rate in patients with disseminated endometrial carcinoma, (www.actabiomedica.it)

Ullmann-like reductive coupling of 1,4-diiodo-2,3,5,6-tetrafluorobenzene, promoted by copper(I) thiophene-2-carboxylate in N -methylpyrrolidinone at room temperature, followed by treatment with lithium aluminum hydride in THF, allowed us to obtain fluorinated poly( para -phenylene) oligomers containing up to five aromatic rings with hydrogen atoms as terminal groups.

We describe a new distance-based metric to measure the strength of collocalization in multi-color microscopy images for user-selected regions. This metric helps to standardize, objectify, quantify, and even automate light microscopy observations. Our new algorithm uses this metric to automatically identify and annotate a donut shaped actomyosin stress fiber bundle evident in vascular smooth muscle cells on certain types of surfaces. Both the metric and the algorithm have been implemented as an open source plugin for the popular ImageJ toolkit. They are available for download at http://code.google.com/p/actin-myosin-plugin/. Using cells stained for the cytoskeletal proteins actin and myosin, we show how characteristics of the identified stress fiber bundle are indicative of the kind of surface the cell is placed upon, and prove that weak spots in this structure are correlated with local membrane extensions. Given the relationship between membrane extension, cell migration, vascular disease, embryonic development, and cancer metastasis we provide that these tools to enable biological research that could improve our quality of life.

Anthocyanins, extracted from grape skin ( Vitis vinifera ), were dissolved in ultrapure aqueous subphase and an oligophenylenevinylene derivative was spread on the subphase surface. Such oligomer was chosen as anionic counterpart of hydrosoluble anthocyanins in order to perform a Langmuir–Schafer film of the dyad. Interface interactions between oligophenylenevinylene derivative and anthocyanins were studied by Brewster angle microscopy and reflection spectroscopy. Additionally, the oligomer exhibits a chemical structure able to ensure an enhancement of the stability under UV–visible irradiations of the film of the dyad without any variation of the natural pigment absorption in the visible range. The visible spectra of cast anthocyanins film and Langmuir–Schafer oligomer/anthocyanins film after exposure to 254 nm irradiation showed a remarkable increase of the film stability, probably due to the screening effect of the oligomer. Preliminary test of a Langmuir–Schafer film of oligophenylenevinylene derivative/anthocyanins as a herbicide sensor showed that sensing is completely reversible, stable and repeatable.

This review reports a survey of our recent results on the synthesis of arylenevinylene polymers and oligomers selectively functionalized with fluorine atoms on aromatic and/or vinylene units. The synthetic methods developed are based on Pd-catalyzed organometallic cross-coupling reactions and in particular on the Stille coupling between vinyl organotin derivatives and aromatic halides. Several compounds have been synthesized, which differ for the number and position of the fluorine atoms on the conjugated backbone, even combined with other functional groups. The effects of fluorination on optical properties both in solution and solid state are discussed.

Nowadays considerable efforts are devoted to the synthesis of low bandgap conjugated polymers for application in organic polymer solar cells. A large variety of low bandgap polymers are prepared by alternating copolymerization of electron-donating donor and electron-withdrawing acceptor units. The interaction between these two units can reduce the polymer bandgap, increasing the sunlight absorption. Benzothiadiazole is commonly used as acceptor block unit in low bandgap polymers. In this contribution we investigate the supramolecular organization and optical properties of thin films of conjugated polymers consisting of benzothiadiazole and thiophene with electron-withdrawing difluorovinylene, and electron-donating vinylene substituents. Atomic force microscopy and spectroscopic ellipsometry are exploited for the analysis of the morphology and optical transitions, respectively. It is found that F-atoms in the vinylene unit yield a blue-shift of the absorption peaks of 0.2 eV respect to the hydrogenated polymer and an increase in the absorption coefficient of fluorinated polymers, which indicates their potential application as photovoltaic material. The morphology evolution of the conjugated polymers blended with a fullerene derivate ([6,6]-phenyl C61-butyric acid methyl ester, PCBM) is also investigated by atomic force microscopy.

The use of an amphiphilic aryleneethynylene fluorophore as a plasma membrane marker in fixed and living mammalian cells and liposome model systems is demonstrated. We show here that the optical properties of the novel dye are almost independent on pH, in the range 5.0–8.0. Spectroscopic characterization performed on unilamellar liposomes ascertained that the fluorescence intensity of the aryleneethynylene fluorophore greatly increases after incorporation in lipidic membranes. Experiments performed on different mammalian cells demonstrated that the novel membrane marker exhibits fast staining and a good photostability that make it a suitable tool for live cell imaging. Importantly, the aryleneethynylene fluorophore was also shown to be a fast and reliable blue membrane marker in classical multicolor immunofluorescence experiments. This study adds new important findings to the recent exploitation of the wide class of aryleneethynylene molecules as luminescent markers for biological investigations.

The extracellular matrix protein tenascin-C plays a critical role in development, wound healing, and cancer progression, but how it is controlled and how it exerts its physiological responses remain unclear. By quantifying the behavior of live cells with phase contrast and fluorescence microscopy, the dynamic regulation of TN-C promoter activity is examined. We employ an NIH 3T3 cell line stably transfected with the TN-C promoter ligated to the gene sequence for destabilized green fluorescent protein (GFP). Fully automated image analysis routines, validated by comparison with data derived from manual segmentation and tracking of single cells, are used to quantify changes in the cellular GFP in hundreds of individual cells throughout their cell cycle during live cell imaging experiments lasting 62 h. We find that individual cells vary substantially in their expression patterns over the cell cycle, but that on average TN-C promoter activity increases during the last 40% of the cell cycle. We also find that the increase in promoter activity is proportional to the activity earlier in the cell cycle. This work illustrates the application of live cell microscopy and automated image analysis of a promoter-driven GFP reporter cell line to identify subtle gene regulatory mechanisms that are difficult to uncover using population averaged measurements.

Dr. M. Ambrico , Dr. P. F. Ambrico CNR-Istituto di Metodologie Inorganiche e dei Plasmi-UOS di Bari70125 Bari, Italy E-mail: marianna.ambrico@ba.imip.cnr.it Dr. A. Cardone , Dr. S. R. Cicco CNR-Istituto di Chimica dei Composti OrganoMetallici-UOS di Bari70125 Bari, Italy Ligonzo , Dr. . T Prof. Augelli . V Dipartimento Interateneo di FisicaUniversita degli Studi di Bari “Aldo Moro”70125 Bari, Italy Dr. R. Di Mundo , Prof. G. M. arinola F Dipartimento di ChimicaUniversita degli Studi di Bari “Aldo Moro”70125 Bari, Italy

The traditional method of cell microscopy can be subjective, due to observer variability, a lack of standardization, and a limited feature set. To address this challenge, we developed an image classifier using a machine learning approach. Our system was able to classify cytoskeletal changes in A10 rat smooth muscle cells with an accuracy of 85% to 99%. These cytoskeletal changes correspond to cell-to-matrix interactions. Analysis of these changes may be used to better understand how these interactions correspond to certain physiologic processes.

Functionalization with fluorine atoms represents a versatile structural modification to finely tune both the emission colour and the electronic properties of organic and organometallic electroluminescent compounds. This paper reports an overview of our systematic investigation on the design and synthesis of the fluorinated version of two important classes of materials for organic light emitting diodes (OLEDs), namely poly(arylenevinylene)s and phosphorescent phenylpyridine Iridium complexes. Synthetic pathways based on organometallic methodologies affording selectively fluorinated molecular structures will be discussed together with a summary of the effect of fluorination on the optical properties of the resulting materials. In particular we will highlight the possibilities offered by the organometallic methodologies as straightforward and resourceful tools to provide a wide series of fluorinated molecular architectures with high regio- and stereoselectivity, mild experimental conditions and good yields.

Ullmann-like reductive coupling of 1,4-diiodo-2,3,5,6-tetrafluorobenzene, promoted by copper(I) thiophene-2-carboxylate in N -methylpyrrolidinone at room temperature, followed by treatment with lithium aluminum hydride in THF, allowed us to obtain fluorinated poly( para -phenylene) oligomers containing up to five aromatic rings with hydrogen atoms as terminal groups.

A high-affinity inhibitor protein called CIP, produced by small truncations of p35, was experimentally identified. P35 is a physiological activator of the cyclin-dependent kinase cdk5. P25 is derived from proteolytic truncation of p35 within "stressed" neurons, and it is associated with the hyperphosphorylation of specific neuronal proteins, typically occurring in neurodegenerative diseases such as Alzheimer's. Here, we report a study of the binding mechanisms of the cdk5-p25 and cdk5-CIP complexes. This provides a better understanding of the source of the inhibitory activity of the protein CIP. We use a geometry-based technique to test the hypothesis that p25's truncation increases the flexibility of CIP and thus prevents cdk5 from reaching its active conformation. Our study is based on a geometry-based alignment algorithm, which aligns two given protein conformations with respect to their interfaces. Our results support the flexibility hypothesis and will be used as a basis for targeted molecular dynamics simulations.

There has been growing interest in developing new semiconducting polymers for applications in optoelectronics (OLEDs) due to their exceptional processability and appealing characteristic of manipulating electronic and optical properties by tuning of molecular structure and self-assembling. This study is an investigation on the interplay among supermolecular organization and optical properties of thin films of the poly[2-(2-ethylhexyloxy)-5-methoxy]-1, 4-phenylenedifluorovinylene (MEH-PPDFV) conjugated polymer, which has fluorinated vinylene units. This interplay is elucidated exploiting atomic force microscopy, spectroscopy ellipsometry, photoluminescence and electroluminescence. Thin films of MEH-PPDFV have been deposited by drop casting on indium-tin-oxide (ITO), quartz and glass substrates. The dependence of polymer chains self-organization and morphology on substrate surface is presented. Furthermore, it is demonstrated that the presence of F-atoms in the vinylene units of the MEH-PPDFV yields a blue optical band gap with the maximum of the fundamental HOMO-LUMO transition at 331 nm and photoluminescence at 458 nm. The OLED built with the above polymer shows a very stable blue-greenish electroluminescence that is also achieved at 504 nm.

Hysteresis behaviour of the current–voltage characteristics collected on spin coated synthetic eumelanin layer embedded in the Au/eumelanin/ITO/glass structure is shown. The effect has been observed under dark both in air and vacuum environment and its magnitude has been found related to the eumelanin hydration state. Moreover, in vacuum and under white light illumination, enhancement of the hysteresis loop area respect to those collected under dark has been observed. Space charge storage and charge trapping/detrapping as possible mechanisms responsible of the observed current–voltage behaviour are discussed. Preliminary experimental results have evidenced the possible integration of eumelanin layers in electro-optical charge storage based memory devices.

Blue-light-emitting poly(p-phenylene vinylene)s with fluorinated vinylene units are presented. It is demonstrated that self-aggregation governs the strength and polarization of the absorption spectra of thin films of these polymers. This indicates that self-assembly of the polymer chains in the films provides a means of tuning the electronic and optical properties of the pi-conjugated systems.

Tetracyanoquinodimethane (TCNQ) and anthraquinone derivatives were synthesized to coordinate the surface of CdSe quantum dots (QDs). These electroactive surfactants are specifically designed to promote the interactions of organic semiconductor quantum dots with a polymer matrix. Starting from colloidal CdSe nanocrystals covered with a layer of TOPO, a process of ligand exchange is worked out in order to obtain new nanocrystal-surfactant heterostructures. We demonstrate that the fluorescence of the nanocrystals is completely quenched upon the formation of the heterostructure CdSe/surfactant indicating an efficient carrier transfer from the QDs to the surfactant.

This study is an investigation on the interplay between supramolecular organization and optical properties of thin films of conjugated polymers with fluorinated vinylene units such as poly[2-(2-ethylhexyloxy)-5-methoxy]-1,4-phenylenedifluorovinylene (MEH-PPDFV) and poly(2-methoxy-5-propyloxysulfonatephenylenedifluorovinylene) (MPS-PPDFV), which are both PPV polymers with fluorinated double bonds with alkoxy chains in the 2 and 5 positions. MEH-PPDFV is the fluorinated version of the widely investigated MEH-PPV, and MPS-PPDFV is characterized by the presence of ionic alkoxy side chains. This interplay is elucidated exploiting atomic force microscopy, spectroscopic ellipsometry and photoluminescence to obtain complementary information. It is demonstrated that the presence of F-atoms in the vinylene units of the MEH-PPDFV yields a blue optical band gap with the maximum of the fundamental HOMO–LUMO transition and of the room temperature photoluminescence at 3.74 eV (331 nm) and at 2.71 eV (458 nm), respectively. The blue-absorption and emission in the thin films are ascribed to the fact that fluorine atoms on the vinylene units prevent π-stacking of polymeric chains. Furthermore, the dependence of morphology, anisotropy in optical properties and photoluminescence properties of films on deposition methodology is also discussed. MEH-PPDFV also emits homogeneous blue-greenish electroluminescence at 2.46 eV (504 nm).

Oligoarylenevinylenes with fluorine atoms in the vinylene units and side-chains with a range of polarities bonded to the aryl rings, have been synthesized via a methodology based on the Stille cross-coupling reaction. All compounds were stereoselectively synthesized with trans double bonds.

A straightforward and general procedure for the introduction of aryl and vinyl substituents in the 5 or 7 position of 8-hydroxyquinoline has been developed. The methodology presented is based upon the Suzuki cross-coupling reaction of aryl or vinyl halides with 5-(4,4,5,5-tetramethyl[1,3,2]dioxaborolan-2-yl)quinolin- 8-ol or 7-(4,4,5,5-tetramethyl[1,3,2]dioxaborolan-2-yl)quinolin-8- ol, respectively, that have been obtained regioselectively starting from 8-hydroxyquinoline

In situ attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroelectrochemistry during oxidation (p-doping) and reduction (n-doping) as well as photoinduced infrared spectroscopy of a random copolymer of 2,3,5,6-tetrafluoro-1,4-phenylenevinylene and 2,5-dioctyloxy-1,4-phenylenevinylene [co(TFPV-DOPV)] is presented. The infrared active vibration (IRAV) patterns obtained during electrochemical oxidation (p-doping) and reduction (n-doping) are different. The copolymer shows photoinduced IRAV bands that are similar to those obtained during electrochemical reduction (n-doping) in contrast to most of the other conjugated polymers which show similarities with oxidation (p-doping) IRAV bands. To our knowledge this is the only p- and n-dopable polymer with different IRAV patterns of charge carriers of both signs, and a similarity between n-doping and photodoping IRAV bands.

This paper presents a method for identifying those parts in a database that are similar to a given query part to be machined and hence can be potentially used as a basis for estimating the machining cost of the query part. We utilize projected feature vectors consisting of feature access directions, feature types, and feature volumes as a basis for assessing shape similarity. We have defined a distance function between two sets of projected feature vectors to assess the similarity between them from the cost estimation point of view. To assess similarity between the two parts, one set of projected feature vectors is transformed in space using rigid body transformations with respect to the other set such that the distance between them is minimized. The distance between the projected feature vectors is used as a measure of similarity between the two parts. The existing parts are rank ordered based on the value of the distance with respect to the new part. The cost of machining the new part can then be estimated by using the cost of previously machined parts that have a very small distance from the new part.Copyright © 2004 by ASME

We investigated the third-order nonlinear optical (NLO) properties of three poly(2′,5′-dioctyloxy-4,4′,4″-terphenylenevinylene)s having different cis / trans -vinylene ratios. The nonlinear measurements were performed at λ =532 nm in chloroform solutions using single-beam Z-scan technique with picosecond laser pulses. All the investigated polymers exhibit a moderate two-photon resonance at this wavelength. On the contrary, the magnitude of the nonlinear refractive index is high and shows a considerable dependence on the cis / trans ratio of the double bonds. The largest third-order nonlinear optical susceptibility, | χ (3) |=(5±1)×10 −10 esu, was measured for a polymer with all monomers having vinylene unit in trans -configuration.

The dependence of the linear optical properties of some soluble poly(terphenylenevinylene)s on the relative amount of cis - and trans -vinylene units has been investigated. A regular blue-shift of the absorption spectra in solution has been observed upon the addition of cis double bonds. Luminescence spectra show a vibronic structure which accounts for the reduced inter-ring torsion in the excited state with respect to the ground state. Moreover, an increased electron–phonon coupling for cis -rich polymers has been observed.

X(3) dependence on relative concentration of electron-rich and electron-deficient monomers has been investigated with Z-scan in copoly(2,3,5,6-tetrafluoro-1.4-phenylenevin ylene-2,5-dialkoxy-1,4-phenylenevinylene)s. The polymer obtained by reacting equimolar quantities of the two monomers showed X(3) as high as (6±2)x10-10 esu.

A series of copoly(2,3,5,6-tetrafluoro-1,4-phenylenevinylene-2,5-dioctyloxy-1,4-phenylenevinylene)s containing variableratios of tetrafluorophenylenevinylene and dialkoxyphenylenevinylene repeating units has been synthesized via the Stillecross-coupling reaction in order to investigate the influence on the (3) of the simultaneous presence of electron-deficientand electron-rich aromatic monomers in the PPV backbone. Third-order nonlinear optical properties of the resultingmaterials have been studied in chloroform solutions at =1064 nm using the picosecond Z-scan technique. The nonlinearrefractive index has been found to be negative, strongly dependent on the copolymer composition, and as high as( 1210 2) 10 cm 2 /W.Keywords: PPV, third-order susceptibility, nonlinear optics, Z-scan. 1. INTRODUCTION Nonlinear optical phenomena are a subject of extensive research because of their potential applications inoptoelectronics and photonics. The routing and modulation of optical signals can be achieved by modifying the refractiveindex of the medium in which the optical signal propagates.

There is a need for tools to classify cells based on their three-dimensional (3D) shape. Cells exist in vivo in 3D, cells are frequently cultured within 3D scaffolds in vitro and 3D scaffolds are used for cell delivery in tissue engineering therapies. Recent work indicates that the physical structure of a tissue engineering scaffold can direct stem cell function by driving stem cells into morphologies that induce their differentiation. Thus, we have developed a rapid method for classifying cells based on their 3D shape. First, random lines are intersected with 3D Z-stacks of confocal images of stem cells. The intersection lengths are stored in histograms, which are then used to train a support vector machine (SVM) learning algorithm to distinguish between stem cells cultured on differentiation-inducing 3D scaffolds and those cultured on non-differentiating flat substrates. The trained SVM is able to properly classify the ?new? query cells over 80% of the time. The algorithm is easily parallelizable and we demonstrate its implementation on a commodity graphics processing unit (GPU). Use of a GPU to run the algorithm increases throughput by over 100-fold as compared to use of a CPU. The algorithm is also progressive, providing an approximate answer quickly and refining the answer over time. This allows further increase in the throughput of the algorithm by allowing the SVM classification scheme to terminate early if it becomes confident enough of the class of the cell being analyzed. These results demonstrate a rapid method for classifying stem cells based on their 3D shape that can be used by tissue engineers for identifying 3D tissue scaffold structures that drive stem cells into shapes that correlate with differentiation.

Poly(2,3,5,6-tetrafluoro-1,4-phenylenevinylene) (PTFPV) was prepared for the first time by the Stille cross-coupling reaction and the resulting material was characterized through MALDI-TOF mass spectrometry, employing a novel sample preparation protocol suitable for insoluble compounds; preliminary optical and electrooptical measurements were performed.