Porous functionalised silica particles: a potential platform for biomolecular screening

Novel, porous, functionalised silica particles have been developed with controlled morphology, which promote covalent attachment of fluorescent dyes which can act as an optical barcode.

A side order of stem cells: The SP phenotype

A defining property of murine hematopoietic stein cells (HSCs) is low fluorescence after staining with Hoechst 33342 and Rhodamine 123. These dyes have proven to be remarkably powerful tools in the purification and characterization of HSCs when used alone or in combination with antibodies directed against stem cell epitopes. Hoechst low cells are described as side population (SP) cells by virtue of their typical profiles in Hoechst red versus Hoechst blue bivariate fluorescent-activated cell sorting dot plots. Recently, excitement has been generated by the findings that putative stem cells from solid tissues may also possess this SP phenotype. SP cells have now been isolated from a wide variety of mammalian tissues based on this same dye efflux phenomenon, and in many cases this cell population has been shown to contain apparently multipotent stem cells. What is yet to be clearly addressed is whether cell fusion accounts for this perceived SP multipotency. Indeed, if low fluorescence after Hoechst staining is a phenotype shared by hematopoietic and organ-specific stem cells, do all resident tissue SP cells have bone marrow origins or might the SP phenotype be a property common to all stem cells? Subject to further analysis, the SP phenotype may prove invaluable for the initial isolation of resident tissue stem cells in the absence of definitive cell-surface markers and may have broad-ranging applications in stem cell biology, from the purification of novel stem cell populations to the development of autologous stem cell therapies.

Geopolymeric adsorbents from fly ash for dye removal from aqueous solution

Adsorbents from coal fly ash treated by a solid-state fusion method using NaOH were prepared. It was found that amorphous aluminosilicate, geopolymers would be formed. These fly ash-derived inorganic polymers were assessed as potential adsorbents for removal of some basic dyes, methylene blue and crystal violet, from aqueous solution. It was found that the adsorption capacity of the synthesised adsorbents depends on the preparation conditions such as NaOH:fly-ash ratio and fusion temperature with the optimal conditions being at 121 weight ratio of Na:fly-ash at 250-350 degrees C. The synthesised materials exhibit much higher adsorption capacity than fly ash itself and natural zeolite. The adsorption isotherm can be fitted by Langmuir and Freundlich models while the two-site Langmuir model producing the best results. It was also found that the fly ash derived geopolymeric adsorbents show higher adsorption capacity for crystal violet than methylene blue and the adsorption temperature influences the adsorption capacity. Kinetic studies show that the adsorption process follows the pseudo second-order kinetics. (c) 2006 Elsevier Inc. All rights reserved.

Quantitative analysis and characterization of biofunctionalized fluorescent silica particles

A strategy for the production and subsequent characterization of biofunctionalized silica particles is presented. The particles were engineered to produce a bifunctional material capable of both (a) the attachment of fluorescent dyes for particle encoding and (b) the sequential modification of the surface of the particles to couple oligonucleotide probes. A combination of microscopic and analytical methods is implemented to demonstrate that modification of the particles with 3-aminopropyl trimethoxysilane results in an even distribution of amine groups across the particle surface. Evidence is provided to indicate that there are negligible interactions between the bound fluorescent dyes and the attached biomolecules. A unique approach was adopted to provide direct quantification of the oligonucleotide probe loading on the particle surface through X-ray photoelectron spectroscopy, a technique which may have a major impact for current researchers and users of bead-based technologies. A simple hybridization assay showing high sequence specificity is included to demonstrate the applicability of these particles to DNA screening.

Adsorption study for removal of basic red dye using bentonite

Colored wastewater poses a challenge to the conventional wastewater treatment techniques. Solid-liquid phase adsorption has been found to be effective for the removal of dyes from effluent. In this paper, the ability of bentonite as an adsorbent for the removal of a commercial dye, Basic Red 2 (BR2), from an aqueous solution has been investigated under various experimental conditions. The adsorption kinetics was shown to be pseudo-second-order. It was found that bentonite had high adsorption capacity for BR2 due to cation exchange. The adsorption equilibrium data can be fitted well by the Langmuir adsorption isotherm model. The effect of the experimental parameters, such as temperature, salt, and pH was investigated through a number of batch adsorption experiments. It was found that the removal of dye increased with the increase in solution pH. However, the change of temperature (15-45 degrees C) and the addition of sodium chloride were found to have little effect on the adsorption process. The results show that electrostatic interactions are not dominant in the interaction between BR2 and bentonite. It was found that the adsorption was a rapid process with 80-90% of the dye removed within the first 2-3 min. Bentonite as an adsorbent is promising for color removal from wastewater.

The fountain amacrine cells of the rabbit retina

We have characterized a distinctive type of bistratified amacrine cell in the rabbit retina at both the single cell and population levels. These cells correspond to the fountain amacrine cells recently identified by MacNeil and Masland (1998). The fountain cells can be distinguished in superfused retinal wholemounts labeled with nuclear dyes, thus enabling them to be targeted for intracellular injection with Neurobiotin. This revealed that the primary dendrites ascend steeply to sublamina b of the inner plexiform layer, where they form an irregular arbor at the border of strata 4 and 5. These dendrites then give rise to multiple varicose processes that descend obliquely to sublamina a, where they form a more extensive arbor in stratum 1. The fountain amacrine cells show strong homologous tracer coupling when injected with Neurobiotin, and this has enabled us to map their density distribution across the retina and to examine the dendritic relationships between neighboring cells. The fountain amacrine cells range in density from 90 to 360 cells/mm(2) and they account for 1.5% of the amacrine cells in the rabbit retina. The thick tapering dendrites in sublamina b form highly territorial arbors that tile the retina with minimal overlap, whereas the thin varicose processes intermingle in sublamina a. The fountain cells are immunopositive for gamma-aminobutyric acid and immunonegative for glycine. We further propose that these cells are homologous to the substance P-immunoreactive (SP-IR) amacrine cells in the cat retina and that they may account for a subset of the SP-IR amacrine cells in the rabbit retina.

A simple, sensitive and selective quantum-dot-based western blot method for the simultaneous detection of multiple targets from cell lysates

Quantum dots (Qdots) are fluorescent nanoparticles that have great potential as detection agents in biological applications. Their optical properties, including photostability and narrow, symmetrical emission bands with large Stokes shifts, and the potential for multiplexing of many different colours, give them significant advantages over traditionally used fluorescent dyes. Here, we report the straightforward generation of stable, covalent quantum dot-protein A/G bioconjugates that will be able to bind to almost any IgG antibody, and therefore can be used in many applications. An additional advantage is that the requirement for a secondary antibody is removed, simplifying experimental design. To demonstrate their use, we show their application in multiplexed western blotting. The sensitivity of Qdot conjugates is found to be superior to fluorescent dyes, and comparable to, or potentially better than, enhanced chemiluminescence. We show a true biological validation using a four-colour multiplexed western blot against a complex cell lysate background, and have significantly improved previously reported non-specific binding of the Qdots to cellular proteins.

Dielectric and electro-optical properties of some cyanobiphenyl liquid-crystals

A variety of methods have been reviewed for obtaining parallel or perpendicular alignment in liquid-crystal cells. Some of these methods have been selected and developed and were used in polarised spectroscopy, dielectric and electro-optic studies. Also, novel dielectric and electro-optic cells were constructed for use over a range of temperature. Dielectric response of thin layers of E7 and E8 (eutectic mixture liquid-crystals) have been measured in the frequency range (12 Hz-100 kHz) and over a range of temperature (183-337K). Dielectric spectra were also obtained for supercooled E7 and E8 in the Hz and kHz range. When the measuring electric field was parallel to the nematic director, one loss peak (low-frequency relaxation process) was observed for E7 and for E8, that exhibits a Debye-type behaviour in the supercooled systems. When the measuring electric field was perpendicular to the nematic director, two resolved dielectric processes have been observed. The phase transitions, effective molecular polarisabilities, anisotropy of polarisabilities and order parameters of three liquid crystal homologs (5CB, 6CB, and 7CB), 60CB and three eutectic nematic mixtures E7, E8, and E607 were calculated using optical and density data measured at several temperatures. The order parameters calculated using the different methods of Vuks, Neugebauer, Saupe-Maier, and Palffy-Muhoray are nearly the same for the liquid crystals considered in the present study. Also, the interrelationship between density and refractive index and the molecular structure of these liquid crystals were established. Accurate dielectric and dipole results of a range of liquid-crystal forming molecules at several temperatures have reported. The role of the cyano-end group, biphenyl core, and flexible tail in molecular association, were investigated using the dielectric method for some molecules which have a structural relationship to the nematogens. Analysis of the dielectric data for solution of the liquid-crystals indicated a high molecular association, comparable to that observed in the nematic or isotropic phases. Electro-optic Kerr effect were investigated for some alkyl cyanobiphenyls, their nematic mixtures and the eutectic mixture liquid-crystals E7 and E8 in the isotropic phase and solution. The Kerr constant of these liquid crystals found to be very high at the nematic-isotropic transition temperatures as the molecules are expected to be highly ordered close to phase transition temperatures. Dynamic Kerr effect behaviour and transient molecular reorientation were also observed in thin layers of some alkyl cyanobiphenyls. Dichroic ratio R and order parameters of solutions containing some azo and anthraquinone dyes in the nematic solvent (E7 and E8), were investigated by the measurement of the intensity of the absorption bands in the visible region of parallel aligned samples. The effective factors on the dichroic ratio of the dyes dissolved in the nematic solvents were determined and discussed.

Towards an improved ocular drug delivery system

The ultimate aim of this project was to design new biomaterials which will improve the efficiency of ocular drug delivery systems. Initially, it was necessary to review the information available on the nature of the tear fluid and its relationship with the eye. An extensive survey of the relevant literature was made. There is a common belief in the literature that the ocular glycoprotein, mucin, plays an important role in tear film stability, and furthermore, that it exists as an adherent layer covering the corneal surface. If this belief is true, the muco-corneal interaction provides the ideal basis for the development of sustained release drug delivery. Preliminary investigations were made to assess the ability of mucin to adhere to polymer surfaces. The intention was to develop a synthetic model which would mimic the supposed corneal/mucin interaction. Analytical procedures included the use of microscopy (phase contrast and fluorescence), fluorophotometry, and mucin-staining dyes. Additionally, the physical properties of tears and tear models were assessed under conditions mimicking those of the preocular environment, using rheological and tensiometric techniques. The wetting abilities of these tear models and opthalmic formulations were also investigated. Tissue culture techniques were employed to enable the surface properties of the corneal surface to be studied by means of cultured corneal cells. The results of these investigations enabled the calculation of interfacial and surface characteristics of tears, tear models, and the corneal surface. Over all, this work cast doubt on the accepted relationship of mucin with the cornea. A corneal surface model was designed, on the basis of the information obtained during this project, which would possess similar surface chemical properties (i.e. would be biomimetic) to the more complex original. This model, together with the information gained on the properties of tears and solutions intended for ocular instillation, could be valuable in the design of drug formulations with enhanced ocular retention times. Furthermore, the model itself may form the basis for the design of an effective drug-carrier.

Food colours:a study of the effects of regulation

In the 1960s the benefits of government regulation of technology were believed to outweigh any costs. But recent studies have claimed that regulation has negative effects on innovation, health and consumer choice. This case study on food colours examines such claims. EFFECTS ON HEALTH were measured by allocating a hazard rating to each colour. The negative list of 1925 removed three harmful colours which were rapidly replaced, so the benefits were short-lived. Had a proposed ban been adopted in the 1860s it would have prevented many years exposure to hazardous mineral colours. The positive list of 1957 reduced the proportion of harmful coal tar dyes from 54% of the total to 20%. Regulations brought a greater reduction in hazard levels than voluntary trade action. Delays in the introduction of a positive list created a significant hazard burden. EFFECTS ON INNOVATION were assessed from patents and discovery dates. Until the 1950s food colours were adopted from textile colours. The major period of innovation for coal tar colours was between 1856 and 1910, finishing well before regulations were made in 1957, so regulations cannot be blamed for the decline. Regulations appear to have spurred the development of at least one new coal tar dye, and many new plant colours, creating a new sector of the dye industry. EFFECTS ON CONSUMER CHOICE were assessed by case studies. Coloured milk, for example, was banned despite its popularity. Regulations have restricted choice, but have removed from the market foods that were nutritionally impoverished and poor value for money. Compositional regulations provided health protection because they reduced total exposure to colours from certain staple foods. Restricting colours to a smaller range of foods would be an effective way of coping with problems of quality and imperfect toxicological knowledge today.

Cyclic and acyclic modifications of 5-aminoimidazole-4-carboxamide

The Introduction gives a brief resume' of the biologically important aspects of 5 -aminoimidazole -4 -carbozamide (1) and explores., in-depth, the synthetic routes to this imidazole. All documented reactions of 5 -aninoimidanole-4 -carboxamide are reviewed in detail, with particular emphasis on the preparation and subsequent coupling reactions of 5 –diazo-imidazole-4 -carboxamide (6). A series of thirteen novel amide 5-amino-2-arylazoimidazole-4-carboxamide derivatives (117-129) were prepared by the coupling of aryldiazonium salts with 5-aminoimidazole-4-carboxamide. Chemical modification of these azo-dyes resulted in the preparation of eight previously unknown acyl derivatives (136-143) Interaction of 5-amino-2-arylazoimidazole-4-carboxides with ethyl formate in sodium ethoxide effected pyrimidine ring closure to the novel 8-arylazohypoxanthines (144 and 145). Several reductive techniques were employed in an effort to obtain the elusive 2,5-diaminoimidazole-4-carboxamide (71),a candidate chemotherapeutic agent, from the arylazoiridazoles. No success can be reported although 5-amino-2-(3-aminoindazol-2-yl) imidazole-4-carboxamide (151) was isolated due to a partial reduction and intramolecular cyclisation of 5-amino72-(2-cyanaphenylazo)imidazole-4-carboxamide (122) .Further possible synthetic approaches to the diaminoimidazole are discussed in Chapter 4. An interesting degradation of a known unstable nitrohydrazone is described in Chapter 5.This resulted in formation of 1, 1-bis(pyrazol--3-ylazo)-1-nitroethane (164) instead of the expected cyclisation to a bicyclic tetrazine N-oxide. An improved preparation of 5-diazoinidazole-4-carboxamide has been achieved, and the diazo-azole formed cycloadducts with isocyanates to yield the hitherto unknown imidazo[5,1-d][1,2,3,5]tetrazin-7(6H)-ones. Eleven derivatives (167-177) of this new ring-system were prepared and characterised. Chemical and spectroscopic investigation showed this ring-system to be unstable under certain conditions, and a comparative study of stability within the group has been made. "Retro-cycloaddition" under protic and photolytic conditions was an unexpected property of 6-substituted imidazo[5,1-d][1,2,3,5]tetrazin--7(0)-ones.Selected examples of the imidazotetrazinone ring-system were tested for antitumour activity. The results of biological evaluation are given in Chapter 7, and have culminated in a Patent application by the collaborating body, May and Baker Ltd. One compound,3-carbamoyl-6-(2-chloro-ethyl)imidazo[5,1-d][1,2,3,5jtetrazin-7(6H)-one (175),shows striking anti-tumour activity in rodent test systems.

Margetinggeschichte:Die Genese einer modernen Sozialtechnik, Hartmut Berghoff

Book revew: Marketinggeschichte: die Genese einer modernen Sozialtechnik [Marketing history: The genesis of a modern social technique], edited by Hartmut Berghoff, Frankfurt/Main, Campus Verlag, 2007, 409 pp., illus., [euro]30.00 (paperback), ISBN 978-3-593-38323-1. This edited volume is the result of a workshop at Göttingen University in 2006 and combines a number of different approaches to the research into the history of marketing in Germany's economy and society. The majority of contributions loosely focus around the occurrence of a ‘marketing revolution’ in the 1970s, which ties in with interpretations of the Americanisation of German business. This revolution replaced the indigenous German idea of Absatzwirtschaft (the economics of sales) with the American-influenced idea of Marketing, which was less functionally oriented and more strategic, and which aimed to connect processes within the firm in order to allow a greater focus on the consumer. The entire volume is framed by Hartmut Berghoff's substantial and informative introduction, which introduces a number of actors and trends beyond the content of the volume. Throughout the various contributions, authors provide explanations of the timing and nature of marketing revolutions. Alexander Engel identifies an earlier revolution in the marketing of dyes, which undergoes major change with the emergence of chemical dyes. While the natural dyestuff had been a commodity, with producers removed from consumers via a global network of traders, chemical dyes were products and were branded at an early stage. This was a fundamental change in the nature of production and sales. As Roman Rossfeld shows in his contribution on the Swiss chocolate industry (which focuses almost exclusively on Suchard), even companies that produced non-essential consumer goods which had always required some measure of labelling grappled for years with the need to develop fewer and higher impact brands, as well as an efficient sales operation. A good example for the classical ‘marketing revolution’ of the 1970s is the German automobile industry. Ingo Köhler convincingly argues that the crisis situation of German car manufacturers – the change from a seller's to a buyer's market, appreciation of the German mark which undermines exports, the oil crises coupled with higher inflation and greater frugality of consumers and the emergence of new competitors – lead companies to refocus from production to the demands of the consumer. While he highlights the role of Ford in responding most rapidly to these problems, he does not address whether the multinational was potentially transferring American knowledge to the German market. Similarly, Paul Erker illustrates that a marketing revolution in transport and logistics happened much later, because the market remained highly regulated until the 1980s. Both Paul Erker and Uwe Spiekermann in their contribution, present comparisons of two different sectors or companies (the tire manufacturer Continental and the logistics company Dachser, and agriculture and trade, respectively). In both cases, however, it remains unclear why these examples were chosen for comparison, as both seem to have little in common and are not always effectively used to demonstrate differences. The weakest section of the book is the development of marketing as an academic discipline. The attempt at sketching the phases in the evolution of marketing as an academic discipline by Ursula Hansen and Matthias Bode opens with an undergraduate-level explanation on the methodology of historical periodisation that seems extraneous. Considerably stronger is the section on the wider societal impact of marketing, and Anja Kruke shows how the new techniques of opinion research was accepted by politics and business – surprisingly more readily by politicians than their commercial counterparts. In terms of contemporary personalities, Hans Domizlaff emerges as one fascinating figure of German marketing history, which several contributors refer to and whose career as the German cigarette manufacturer Reemtsma is critically analysed by Tino Jacobs. Domizlaff was Germany's own ‘marketing guru’, whose successful campaigns led to the wide-ranging reception of his ideas about the nature of good branding and marketing. These are variously described as intuitive, elitist, and sachlich, a German concept of a sober, fact-based, and ‘no frills’ approach. Domizlaff did not believe in market research. Rather, he saw the genius of the individual advertiser as key to intuitively ascertaining the people's moods, wishes, and desires. This seems to have made him peculiarly suited to the tastes of the German middle class, according to Thomas Mergel's contribution on the nature of political marketing in the republic. Especially in politics, any form of hard sales tactics were severely frowned upon and considered to demean the citizen as incapable of making an informed choice, a mentality that he dates back to the traditions of nineteenth-century liberalism. Part of this disdain of ‘selling politics like toothpaste’ was also founded on the highly effective use of branding by the National Socialists, who identified their party through the use of an increasingly standardised image of Adolf Hitler and the swastika. Alexander Schug extends on previous research that criticised the simplistic notion of Hitler's charisma as the only explanation of the popular success and distances his approach from those who see it in terms of propaganda and demagogy. He argues that the NSDAP used the tools of advertising and branding precisely because they had to introduce their new ideology into a political marketplace dominated by more established parties. In this they were undoubtedly successful, more so than they intended: as bakers sold swastika cookies and butchers formed Führer heads out of lard, the NSDAP sought to regain control over the now effectively iconic images that constituted their brand, which was in danger of being trivialised and devalued. Key to understanding the history of marketing in Germany is on the one hand the exchange of ideas with the United States, and on the other the impact of national-socialist policies, and the question whether they were a force of modernisation or retardation. The general argument in the volume appears to favour the latter explanation. In the 1930s, some of the leading marketing experts emigrated to the USA, leaving German academia and business isolated. The aftermath of the Second World War left a country that needed to increase production to satisfy consumer demand, and there was little interest in advanced sales techniques. Although the Nazis were progressive in applying new marketing methods to their political campaign, this retarded the adoption of sales techniques in politics for a long time. Germany saw the development of idiosyncratic approaches by people like Domizlaff in the 1930s and 1940s, when it lost some leading thinkers, and only engaged with American marketing conceptions in the 1960s and 1970s, when consumers eventually became more important than producers.