Optical coherence tomography: a potential tool for unsupervised prediction of treatment response for Port-Wine Stains.

Background: Treatment of Port-Wine Stains (PWS) suffers from the absence of a reliable real-time tool for monitoring a clinical endpoint. Response to treatment varies substantially according to blood vessel geometry. Even though optical coherence tomography (OCT) has been identified as a modality with potential to suit this need, it has not been introduced as a standard clinical monitoring tool.

Review: optical micrometer resolution scanning for non-invasive grading of precancer in the human uterine cervix.

Management of cervical precancer is archetypal for other cancer prevention programmes but has to consider diagnostic and logistic challenges. Numerous optical tools are emerging for non-destructive near real-time early diagnosis of precancerous lesions of the cervix. Non-destructive, real-time imaging modalities have reached pre-commercial status, but high resolution mapping tools are not yet introduced in clinical settings.

Towards automated classification of clinical optical coherence tomography data of dense tissues.

The native contrast of optical coherence tomography (OCT) data in dense tissues can pose a challenge for clinical decision making. Automated data evaluation is one way of enhancing the clinical utility of measurements. Methods for extracting information from structural OCT data are appraised here.

Near real-time classification of optical coherence tomography data using principal components fed linear discriminant analysis.

An optical coherence tomography (OCT) prediction algorithm is designed and tested on a data set of sample images (taken from vegetables and porcine tissues) to demonstrate proof of concept. Preprocessing and classification of data are fully automated, at a rate of 60,000 A-scansmin on a standard computer and can be considered to deliver in near real-time. A data set consisting of nine groups was classified correctly in 82% of cases after cross-validation.

From 3D to 2D: a review of the molecular imprinting of proteins.

Molecular imprinting is a generic technology that allows for the introduction of sites of specific molecular affinity into otherwise homogeneous polymeric matrices. Commonly this technique has been shown to be effective when targeting small molecules of molecular weight <1500, while extending the technique to larger molecules such as proteins has proven difficult. A number of key inherent problems in protein imprinting have been identified, including permanent entrapment, poor mass transfer, denaturation, and heterogeneity in binding pocket affinity, which have been addressed using a variety of approaches.

Prospects for clinical application of electronic-nose technology to early detection of Mycobacterium tuberculosis in culture and sputum.

Ziehl-Neelsen (ZN) staining for the diagnosis of tuberculosis (TB) is time-consuming and operator dependent and lacks sensitivity. A new method is urgently needed. We investigated the potential of an electronic nose (EN) (gas sensor array) comprising 14 conducting polymers to detect different Mycobacterium spp.

Root establishment of perennial ryegrass (L. perenne) in diesel contaminated subsurface soil layers.

The efficiency of rhizosphere biodegradation of petroleum hydrocarbons heterogeneously distributed in soils is dependent on the ability of plant roots to prospect into contaminated zones. Rhizobox experiments were conducted to study the influence of diesel contaminated layers on the spatial distribution and the development of the roots of perennial ryegrass. Root distribution and root and shoot development were monitored over time.

Development of a disposable pyruvate biosensor to determine pungency in onions (Allium cepa L.).

A disposable prototype pyruvate biosensor was constructed using pyruvate oxidase immobilised on mediated meldolas blue electrodes to determine pungency in onions (Allium cepa L.). The optimum operating potential was +150 mV (versus Ag/AgCl).

Confident protein identification using the average peptide score method coupled with search-specific, ab initio thresholds.

Perhaps the greatest difficulty in interpreting large sets of protein identifications derived from mass spectrometric methods is whether or not to trust the results. For such experiments, the level of confidence in each protein identification made needs to be far greater than the often used 95% significance threshold to avoid the identification of many false-positives. To provide higher confidence results, we have developed an innovative scoring strategy coupling the recently published Average Peptide Score (APS) method with pre-filtering of peptide identifications, using a simple peptide quality filter.

Langmuir-Blodgett films of preformed polymers containing biphenyl groups.

Polymers containing liquid crystal groups have been studied previously as waveguides, and they have been deposited as spacer materials with various chromophores to form alternating films However, only a few members of this group of materials have been studied in any detail, and very little structural information has been obtained so far. Therefore, a more detailed examination of these materials as mono- and multilayers was undertaken. A new group of materials including the same mesogenic group, polymeric sulfones, was also studied.

Structured thin films as functional components within biosensors.

This review provides an introduction to the field of thin films formed by Langmuir-Blodgett or self-assembly techniques and discusses applications in the field of biosensors. The review commences with an overview of thin films and methods of construction. Methods covered will include Langmuir-Blodgett film formation, formation of self-assembled monolayers such as gold-thiol monolayers and the formation of multilayers by the self-assembly of polyelectrolytes.

Sonochemically fabricated acetylcholinesterase micro-electrode arrays within a flow injection analyser for the determination of organophosphate pesticides.

This report describes the development of novel sonochemically fabricated, bioengineered acetylcholinesterase and polyaniline carbon/cobalt phthalocyanine biosensors for the ultra-sensitive determination of a number of different pesticides. Arrays of this type typically have population micro-electrode densities of up to approximately 2 x 10(5) cm(-2); these represent the highest micro-electrode population densities reported to date by any fabrication means. The enzymatic response of the sensors is inhibited upon incubation with the pesticide, and we have shown that Dichlorvos, Parathion and Azinphos may be determined down to concentrations of approximately 1 x 10(-17) M, approximately 1 x 10(-16) M and approximately 1 x 10(-16) M, respectively.

Comparing the synergistic effects of oleic acid and dimethyl sulfoxide as vehicles for optical clearing of skin tissue in vitro.

Recently, the tissue optical clearing technique has shown great potential in enhancing the capabilities of non-invasive light-based diagnostic and imaging techniques due to increased light penetration into tissue. In order to facilitate the clinical availability of the tissue optical clearing technique by the use of hyperosmotic agents, this study introduces oleic acid, a mono-unsaturated fatty acid which is generally recognised as safe, as an enhancer, and investigates the synergistic effect of oleic acid and propylene glycol on the optical clearing of skin tissue in vitro. Experimental results from near infrared spectroscopy, mass loss measurement and skin permeability assessment show that, when compared with dimethyl sulfoxide (DMSO) as an enhancer, oleic acid has a similar clearing effect.

Species differentiation by DNA-modified carbon electrodes using an ac impedimetric approach.

A simple and novel electrochemical biosensor based approach is described for differentiating between differing species of fish on the basis of DNA hybridisation events. Screen-printed carbon electrodes modified with a variety of polymers were used to immobilise commercially available DNA in a single-stranded form. AC impedimetric measurements were firstly carried out on these systems and then upon exposure to single-stranded DNA solutions.

Improvement of low-level light imaging performance using optical clearing method.

Low-level light-emitting imaging technique often detects the light emerged at the tissue surface that is generated internally from a specific target. However, in most cases, the high scattering nature of biological tissue limits the sensitivity and spatial resolution of this imaging modality. In this paper, we report that a significant improvement of chemiluminescence (CL) imaging performance in terms of both sensitivity and spatial resolution can be achieved by use of the topical application of glycerol solution onto tissue sample, i.

Photochemical polymerization of thiophene derivatives in aqueous solution.

A novel method of photochemical polymerization of thiophene derivatives in aqueous solution catalyzed by potassium dichromate and initiated by illumination is described.

Changing surface hydro- and oleophobicity with resorcinarene multilayers-a simple water/oil proofing process.

Resorcinarenes (resorcinol-aldehyde tetramers) of appropriate structures have been shown to change the hydro- and oleophilicities of a variety of surfaces. The phenomenon results from attachment of the rim of the bowl-like molecules to hydrophilic surfaces. Hydrophobic (alkyl) and oleophobic (perfluoro alkyl) "legs" attached to the bowls then determine the immediate surface property.

Sonochemically fabricated microelectrode arrays for biosensors offering widespread applicability: Part I.

A novel and patented procedure is described for the sonochemical fabrication of a new class of microelectrode array based sensor with electrode element populations of up to 2 x 10(5) cm(-2). For some years it has been accepted that microelectrode arrays offer an attractive route for lowering minimum limits of detection and imparting stir (convectional mass transport) independence to sensor responses; despite this no commercial biosensors, to date, have employed microelectrode arrays, largely due to the cost of conventional fabrication routes that have not proved commercially viable for disposable devices. Biosensors formed by our sonochemical approach offer unrivalled sensitivity and impart stir independence to sensor responses.

Monitoring haemodialysis using electronic nose and chemometrics.

An ever-increasing number of patients have to undergo regular renal dialysis to compensate for acute or chronic renal failure. The adequacy of the treatment has a profound effect on patients' morbidity and mortality. Therefore, it is necessary to assess the delivered dialysis dose.

Synergistic effect of hyperosmotic agents of dimethyl sulfoxide and glycerol on optical clearing of gastric tissue studied with near infrared spectroscopy.

In an effort to find an effective concentration that could minimize the side effect for clinical applications, and to understand the potential synergistic effect of hyperosmotic agents on optical clearing of gastric tissues, porcine stomach tissues (pyloric mucosa) applied with a mixed solution of glycerol and dimethyl sulfoxide (DMSO) are investigated with near infrared reflectance spectroscopy. Five chemical solutions, containing 80% glycerol, 50% DMSO, 50% glycerol with 10% DMSO, 20% DMSO and 30% DMSO, respectively, are prepared and studied; all of which show significant improvement in light transmittance, and thus reduction of the light scattering of tissue. It is found that, among the solutions investigated, 50% glycerol with 30% DMSO achieves the best clearing effect on the improvement of light penetration.

Dynamic optical clearing effect of tissue impregnated with hyperosmotic agents and studied with optical coherence tomography.

The depth of light penetration into highly scattering tissues can be improved by the application of biocompatible and osmotically active chemical agents. We compare the dynamics of optical clearing of tissue by the topical application of glycerol and dimethyl sulfoxide (DMSO) using optical coherence tomography (OCT). It is demonstrated experimentally that both agents can largely improve the OCT imaging depth for porcine stomach tissue.

Using a linked soil model emulator and unsaturated zone leaching model to account for preferential flow when assessing the spatially distributed risk of pesticide leaching to groundwater in England and Wales.

Although macropore flow is recognized as an important process for the transport of pesticides through a wide range of soils, none of the existing spatially distributed methods for assessing the risk of pesticide leaching to groundwater account for this phenomenon. The present paper presents a spatially distributed modelling system for predicting pesticide losses to groundwater through micro- and macropore flow paths. The system combines a meta version of the mechanistic, dual porosity, preferential flow pesticide leaching model MACRO (the MACRO emulator), which describes pesticide transport and attenuation in the soil zone, to an attenuation factor leaching model for the unsaturated zone.

Enhanced sensitivity and spatial resolution for in vivo imaging with low-level light-emitting probes by use of biocompatible chemical agents.

We describe a technique that uses biocompatible chemical agents to enhance both the sensitivity and the resolution of in vivo imaging with low-level light-emitting probes. We demonstrate experimentally, with chemiluminescence (CL) imaging in vitro as an example, that the detected intensity of CL from treated 3-mm-thick skin tissue is approximately fivefold stronger than that from untreated skin. The spatial resolution correspondingly increases approximately threefold.

Development of a common biosensor format for an enzyme based biosensor array to monitor fruit quality.

Individual enzyme-based biosensors involving three-electrode systems were developed for the detection of analytes comprising markers of the stage of maturity and quality in selected fruits of economic importance to tropical countries. Importantly, a common fabrication format has been developed to simplify manufacture and allow future integration of the individual sensors into a single multi-sensor array. Specifically, sensors for beta-D-glucose, total D-glucose, sucrose and ascorbic acid have been developed.

Determination of flow velocity vector based on Doppler shift and spectrum broadening with optical coherence tomography.

We describe a technique that uses Doppler optical coherence tomography to estimate accurately the scattering fluid-flow velocity without a priori knowledge of the Doppler angle. Our technique is based on the combined use of the Doppler shift on the interference signal and the Doppler spectrum broadening caused by the particles moving across the probe beam. It is shown that the estimated values of the Doppler angle and average fluid velocity from the experiments agree well with the preset values.