Intercellular calcium waves in primary cultured rat mesenteric smooth muscle cells are mediated by connexin43.

Intercellular Ca(2+) wave propagation between vascular smooth muscle cells (SMCs) is associated with the propagation of contraction along the vessel. Here, we characterize the involvement of gap junctions (GJs) in Ca(2+) wave propagation between SMCs at the cellular level. Gap junctional communication was assessed by the propagation of intercellular Ca(2+) waves and the transfer of Lucifer Yellow in A7r5 cells, primary rat mesenteric SMCs (pSMCs), and 6B5N cells, a clone of A7r5 cells expressing higher connexin43 (Cx43) to Cx40 ratio. Mechanical stimulation induced an intracellular Ca(2+) wave in pSMC and 6B5N cells that propagated to neighboring cells, whereas Ca(2+) waves in A7r5 cells failed to progress to neighboring cells. We demonstrate that Cx43 forms the functional GJs that are involved in mediating intercellular Ca(2+) waves and that co-expression of Cx40 with Cx43, depending on their expression ratio, may interfere with Cx43 GJ formation, thus altering junctional communication.

Fabrication and characterisation of polymer optical fibers for smart sensing and optical amplification

The thesis presented the fabrication and characterisation of polymer optical fibers in their applications as optical amplifier and smart sensors.Optical polymers such as PMMA are found to be a very good host material due to their ability to incorporate very high concentration of optical gain media like fluorescent dyes and rare earth compounds. High power and high gain optical amplification in organic dye-doped polymer optical fibers is possible due to extremely large emission cross sections of oyes. Dye doped (Rhodamine 6G) optical fibers were fabricated by using indigenously developed polymer optical fiber drawing tower. Loss characterization of drawn dye doped fibers was carried out using side illumination technique. The advantage of the above technique is that it is a nondestructive method and can also be used for studying the uniformity in fiber diameter and doping. Sensitivity of the undoped polymer fibers to temperature and microbending were also studied in its application in smart sensors.Optical amplification studies using the dye doped polymer optical fibers were carried out and found that an amplification of l8dB could be achieved using a very short fiber of length lOcm. Studies were carried out in fibers with different dye concentrations and diameter and it was observed that gain stability was achieved at relatively high dye concentrations irrespective of the fiber diameter.Due to their large diameter, large numerical aperture, flexibility and geometrical versatility of polymer optical fibers it has a wide range of applications in the field of optical sensing. Just as in the case of conventional silica based fiber optic sensors, sensing techniques like evanescent wave, grating and other intensity modulation schemes can also be efficiently utilized in the case of POF based sensors. Since polymer optical fibers have very low Young's modulus when compared to glass fibers, it can be utilized for sensing mechanical stress and strain efficiently in comparison with its counterpart. Fiber optic sensors have proved themselves as efficient and reliable devices to sense various parameters like aging, crack formation, weathering in civil structures. A similar type of study was carried out to find the setting characteristics of cement paste used for constructing civil structures. It was found that the measurements made by using fiber optic sensors are far more superior than that carried out by conventional methods. More over,POF based sensors were found to have more sensitivity as well.

Biological Photonic Crystals: Diatoms

The aim of this work was to produce a variety of fluorescent diatom cell wall material as a basis for spectroscopic investigations of the influence of the photonic structure on the emission of an incorporated laser dye. This goal was achieved by the method of in vivo-fluorochromation, in which the fluorescence dyes are incorporated by the diatom cells during cell wall formation. Several fluorescent dyes (mostly rhodamines) known as strong laser dyes, were tested for a possible application within this method. The results of this work show that half of the tested rhodamines can be applied for an in vivo-fluorochromation of diatom cells. For a successful incorporation into the diatom cell wall, a relatively low toxicity to diatom cells is necessary. Replacement of the carbon acid function at the carboxyphenyl ring of the rhodamine by a methyl or ethylester function showed to convert a rhodamine of relatively low toxicity to a rhodamine leading to severe lethal effects within the cells. In contrast to their carbon acid forms, which posses a net neutral charge of the molecule, rhodamine esters exhibit a net positive charge. The enhanced toxicological effects seem to be due to an increased accumulation of positive charged rhodamines within the mitochondria, an increased hydrophobicity due to the attachment of an alkyl substituent, an increased retention time of the dyes within the mitochondria and a therefore stronger negative effect on the mitochondrial membrane bound energy processes of the diatom cell. Therefore rhodamines with a positive net charge deriving from a methyl or ethylester function at the carboxy phenyl ring instead of a carbon acid substituent showed not to be suitable for long-term investigations/ biomineralization studies of diatoms. Investigations performed on diatom species of different orders showed that rhodamine 19, rhodamine B, and rhodamine 101 can presumably be successfully applied for in vivo-fluorochromation to all diatom species. The results obtained here can help to find further laser dyes for an in vivo-fluorochromation of diatom cells and therefore for the production of fluorescent nanostructural elements for a detailed optical investigation of the diatom cell wall. First optical measurements performed on in vivo-fluorochromated cell walls did not give any hints concerning the photonic structure of the diatom cell. Cell wall parts with different nanostructural elements were investigated and by comparison of the obtained fluorescence emission spectra, no special features that might derive from photonic structural effects could be observed. Results concerning the concentration dependent shifts within the emission spectra, as well as the decrease of fluorescence intensity of the stained cell wall structures with increasing dye concentration, depict that several effects occurring by interaction of the molecules within the cell wall can have an impact on the technical application of fluorescent cell walls. It can be assumed that the investigation of the photonic crystal behaviour and the possibility to achieve laser action within the diatom cell wall can be hampered by molecular interactions. The results give hints to prevent such obstacles. Comparison of the recent findings and state of the art of in vivo-fluorochromation of diatom cell wall material, make clear that the here presented results are of importance and can offer a considerable contribution to the development and establishment of new biosilification markers, for diatoms as well as for other biosilifying organisms.

Development of a PCR-based assay for rapid and reliable identification of pathogenic Fusaria

Identification of Fusarium species has always been difficult due to confusing phenotypic classification systems. We have developed a fluorescent-based polymerase chain reaction assay that allows for rapid and reliable identification of five toxigenic and pathogenic Fusarium species. The species includes Fusarium avenaceum, F. culmorum, F. equiseti, F. oxysporum and F. sambucinum. The method is based on the PCR amplification of species-specific DNA fragments using fluorescent oligonucleotide primers, which were designed based on sequence divergence within the internal transcribed spacer region of nuclear ribosomal DNA. Besides providing an accurate, reliable, and quick diagnosis of these Fusaria, another advantage with this method is that it reduces the potential for exposure to carcinogenic chemicals as it substitutes the use of fluorescent dyes in place of ethidium, bromide. Apart from its multidisciplinary importance and usefulness, it also obviates the need for gel electrophoresis. (C) 2002 Published by Elsevier Science B.V. on behalf of the Federation of European Microbiological Societies.

Covalent attachment of 3,4,9,10-perylenediimides onto the walls of mesoporous molecular sieves MCM-41 and SBA-15

This work describes the covalent grafting of 3,4,9,10-perylenediimides (PDI), which are fluorescent dyes with very interesting optical properties, onto the walls of mesoporous molecular sieves MCM-41 and SBA-15. The mesoporous materials were first treated with 3-aminopropyltriethoxysilane (APTES) in anhydrous toluene, generating amine-containing surfaces. The amine-containing materials were then reacted with 3,4,9,10-perylenetetracarboxylic dianhydride (PTCA), generating surface-grafted PDI. Infrared spectra of the materials showed that the reaction with amino groups took place at both anhydride ends of the PTCA molecule, resulting in surface attached diimides. No sign of unreacted anhydride groups were found. The new materials, designated as MCMN2PDI and SBAN(2)PDI, presented absorption and emission spectra corresponding to weakly coupled PDI chromophores, in contrast to the strongly coupled rings usually found in solid PDI samples. The materials showed a red fluorescence, which could be observed by the naked eye under UV irradiation or with a fluorescence microscope. The PDI-modified mesoporous materials showed electrical conductivity when pressed into a pellet. The results presented here show that the new materials are potentially useful in the design of nanowires. (C) 2007 Elsevier Inc. All rights reserved.

Comparison of the analytical performance of electrophoresis microchannels fabricated in PDMS, glass, and polyester-toner

This paper compares the analytical performance of microchannels fabricated in PDMS, glass, and polyester-toner for electrophoretic separations. Glass and PDMS chips were fabricated using well-established photolithographic and replica-molding procedures, respectively. PDMS channels were sealed against three different types of materials: native PDMS, plasma-oxidized PDMS, and glass. Polyester-toner chips were micromachined by a direct-printing process using an office laser printer. All microchannels were fabricated with similar dimensions according to the limitations of the direct-printing process (width/depth 150 mu m/12 mu m). LIF was employed for detection to rule out any losses in separation efficiency due to the detector configuration. Two fluorescent dyes, coumarin and fluorescein, were used as model analytes. Devices were evaluated for the following parameters related to electrophoretic separations: EOF, heat dissipation, injection reproducibility, separation efficiency, and adsorption to channel wall.

Fluorescence and conductivity studies on wool

An optimized synthetic method for the production of fluorescent conductive wool using pyrene, rhodamine B and fluorescein is reported. The application of fluorescent conductive polymers to wool was studied using solution and mist polymerization techniques. The effects of incorporating fluorescent dopants into the polymerization solution as well as the encapsulation of fluorescent dyes in a polypyrrole (PPy) micelle were also investigated. It was determined on the basis of both conductivity and fluorescence measurements that the encapsulation of dyes in PPy onto the surface of textiles gave the best results.

Effects of backwashing on PVDF membrane fouling by organic foulants

Membrane is usually subject to fouling by various organic foulants, such as yeast, protein and sodium alginate during filtration. Backwashing is a common practice to reduce membrane fouling. It is essential to evaluate the effects of backwashing on fouling in order to optimize operational parameters. In this experiment, poly(vinylidene fluoride) (PVDF) membranes were used to filter organic foulants from suspensions in a dead-end stirred cell. Three types of organic foulants including yeast, protein and sodium alginate which were stained with fluorescent dyes before filtration were used with different combinations in the experiments. After filtration, the PVDF membrane was backwashed.

Consequently, a stack of images, instrumental data and sample data were captured from the fouling layers on the PVDF membrane surface using confocal laser scanning microscope (CLSM) and its associated image acquisition software LAS AF. Then, the quality of the images was enhanced for better visualization and a set of quantitative fouling data were derived by using the software code developed by the project team at Deakin University.

This collection contains raw image data of poly(vinylidene fluoride) (PVDF) membrane’s fouling layer when three types of organic foulants present, which are captured by confocal laser scanning microscopy (CLSM) and its software, and the instrumental and sample metadata, the processed image data and the geometrical structure properties of the fouling layer. By comparing with the same membrane without backwashing, the efficiency of backwashing was computed.

This data collection would be useful to evaluate the backwashing efficiency of PVDF membrane in order to optimize frequency and operational conditions of backwashing by membrane materials researchers and water researchers.

Polycarbonate (PC) membrane fouling by protein and sodium alginate

This data was obtained from an experiment, where polycarbonate (PC) membranes were used to filter two types of organic foulants, including protein and sodium alginate, from suspension in a dead-end filtration cell. These model foulants were stained with fluorescent dyes before filtration. Consequently, a stack of images were captured from the fouling layers on the PC membrane surface using confocal laser scanning microscope (CLSM). This data collection contains 105 2D images of polycarbonate (PC) membranes fouling layer. This data collection would be useful to investigate membrane fouling mechanism by membrane materials researchers and water researchers.

Study on the fouling phenomena of poly(vinylidene fluoride) (PVDF) membrane by protein and yeast

This sub-collection is the result of an investigation into the mechanism of organic fouling in membrane filtration processes. In this experiment, poly(vinylidene fluoride) (PVDF) membranes were used to filter two types of organic foulants, protein and yeast with a concentration of 50mg/l and 20 mg/l, respectively, from suspension in a dead-end filtration cell. These model foulants were stained with fluorescent dyes before filtration. This dataset contains a stack of images of the fouling layer on the PVDF membrane surface captured by a confocal laser scanning microscope (CLSM) and its associated acquisition software. This dataset would be useful to researchers who are investigating the membrane organic fouling mechanism so that new membrane materials and new anti-fouling surface treatment technologies can be developed for water and wastewater industry in the future.

Evaluating backwashing efficiency of poly(vinylidene fluoride) (PVDF) membrane fouled by protein and yeast

This collection is the result of an investigation into the backwashing efficiency of poly(vinylidene fluoride) (PVDF) membrane fouled by two types of organic foulants, protein and yeast. In this experiement, poly(vinylidene fluoride) (PVDF) membrane was used to filter those organic foulants from suspensions in a dead-end stirred cell. The organic foulants were stained with fluorescent dyes before filtration. After filtration, the PC membrane was backwashed. Consequently, a stack of images were captured from the fouling layers on the PVDF membrane surface using confocal laser scanning microscope (CLSM) and its associated image acquisition software. It contains image data of poly(vinylidene fluoride) (PVDF) membranes' fouling layer when two types of organic foulants (protein and yeast) present. By comparing with the same membrane without backwashing, the efficiency of backwashing was computed. This data collection would be useful to researchers who are evaluating the backwashing efficiency of PVDF membrane in order to optimize frequency and operational conditions of backwashing by membrane materials and by water.

Evaluating backwashing efficiency of polycarbonate (PC) membrane fouled by protein and sodium alginate

This collection is the result of an investigation into the backwashing efficiency of polycarbonate (PC) membrane fouled by two types of organic foulants, protein and sodium alginate. In this experiement, polycarbonate (PC) membrane was used to filter those organic foulants from suspensions in a dead-end stirred cell. The organic foulants were stained with fluorescent dyes before filtration. After filtration, the PC membrane was backwashed. Consequently, a stack of images were captured from the fouling layers on the PC membrane surface using confocal laser scanning microscope (CLSM) and its associated image acquisition software. It contains image data of polycarbonate (PC) membranes' fouling layer when two types of organic foulants (protein and sodium alginate) are present. By comparing with the same membrane without backwashing, the efficiency of backwashing was computed. This data collection would be useful to researchers evaluating the backwashing efficiency of PC membrane in order to optimize frequency and operational conditions of backwashing by membrane materials researchers and by water..

Evaluating backwashing efficiency of poly(vinylidene fluoride) (PVDF) membrane fouled by yeast and sodium alginate

This collection is the result of an investigation into the backwashing efficiency of poly(vinylidene fluoride) (PVDF) membrane fouled by yeast and sodium alginate. In this experiement, poly(vinylidene fluoride) (PVDF) membrane was used to filter two types of organic foulants from suspensions in a dead-end stirred cell. The organic foulants including yeast and sodium alginate were stained with fluorescent dyes before filtration. After filtration, the PC membrane was backwashed. Consequently, a stack of images were captured from the fouling layers on the PVDF membrane surface using confocal laser scanning microscope (CLSM) and its associated image acquisition software. The data collection contains image data of poly(vinylidene fluoride) (PVDF) membranes' fouling layer when two types of organic foulants (yeast and sodium alginate) are present. By comparing with the same membrane without backwashing, the efficiency of backwashing was computed. The collection would be useful to researchers evaluating the backwashing efficiency of poly(vinylidene fluoride) (PVDF) membrane in order to optimize frequency and operational conditions of backwashing by membrane materials and by water.

Evaluating backwashing efficiency of polycarbonate (PC) membrane fouled by protein, sodium alginate and yeast

This collection is the result of an investigation into the backwashing efficiency of polycarbonate (PC) membrane fouled by three types of organic foulants, protein, sodium alginate and yeast. In this experiement, polycarbonate (PC) membrane was used to filter those organic foulants from suspensions in a dead-end stirred cell. The organic foulants were stained with fluorescent dyes before filtration. After filtration, the PC membrane was backwashed. Consequently, a stack of images were captured from the fouling layers on the PC membrane surface using confocal laser scanning microscope (CLSM) and its associated image acquisition software. It contains image data of polycarbonate (PC) membranes' fouling layer when three types of organic foulants (protein, sodium alginate and yeast) are present. By comparing with the same membrane without backwashing, the efficiency of backwashing was computed. This data collection would be useful to researchers who are evaluating the backwashing efficiency of PC membrane in order to optimize frequency and operational conditions of backwashing by membrane materials and by water..

Study on the fouling phenomena of poly(vinylidene fluoride) (PVDF) membrane by protein and sodium alginate

This sub-collection is the result of an investigation into the mechanism of organic fouling in membrane filtration processes. In this experiment, poly(vinylidene fluoride) (PVDF) membranes were used to filter two types of organic foulants, protein and sodium alginate with a concentration of 50mg/l and 40 mg/l, respectively, from suspension in a dead-end filtration cell. These model foulants were stained with fluorescent dyes before filtration. This dataset contains a stack of images of the fouling layer on the PVDF membrane surface captured by a confocal laser scanning microscope (CLSM) and its associated acquisition software. This dataset would be useful to researchers who are investigating the membrane organic fouling mechanism so that new membrane materials and new anti-fouling surface treatment technologies can be developed for water and wastewater industry in the future.