Chromo- and fluorogenic Organometallic Sensors

Compounds that change their absorption and/or emission properties in the presence of a target ion or molecule have been studied for many years as the basis for optical sensing. Within this group of compounds, a variety of organometallic complexes have been proposed for the detection of a wide range of analytes such as cations (including H+), anions, gases (e.g. O2, SO2, organic vapours), small organic molecules, and large biomolecules (e.g. proteins, DNA). This chapter focuses on work reported within the last few years in the area of organometallic sensors. Some of the most extensively studied systems incorporate metal moieties with intense long-lived metal-to-ligand charge transfer (MLCT) excited states as the reporter or indicator unit, such as fac-tricarbonyl Re(I) complexes, cyclometallated Ir(III) species, and diimine Ru(II) or Os(II) derivatives. Other commonly used organometallic sensors are based on Pt-alkynyls and ferrocene fragments. To these reporters, an appropriate recognition or analyte-binding unit is usually attached so that a detectable modification on the colour and/or the emission of the complex occurs upon binding of the analyte. Examples of recognition sites include macrocycles for the binding of cations, H-bonding units selective to specific anions, and DNA intercalating fragments. A different approach is used for the detection of some gases or vapours, where the sensor's response is associated with changes in the crystal packing of the complex on absorption of the gas, or to direct coordination of the analyte to the metal centre.

Animal-borne sensors successfully capture the real-time thermal properties of ocean basins

Climate change is perhaps the most pressing and urgent environmental issue facing the world today. However our ability to predict and quantify the consequences of this change is severely limited by the paucity of in situ oceanographic measurements. Marine animals equipped with sophisticated oceanographic data loggers to study their behavior offer one solution to this problem because marine animals range widely across the world's ocean basins and visit remote and often inaccessible locations. However, unlike the information being collected from conventional oceanographic sensing equipment, which has been validated, the data collected from instruments deployed on marine animals over long periods has not. This is the first long-term study to validate in situ oceanographic data collected by animal oceanographers. We compared the ocean temperatures collected by leatherback turtles (Dermochelys coriacea) in the Atlantic Ocean with the ARGO network of ocean floats and could find no systematic errors that could be ascribed to sensor instability. Animal-borne sensors allowed water temperature to be monitored across a range of depths, over entire ocean basins, and, importantly, over long periods and so will play a key role in assessing global climate change through improved monitoring of global temperatures. This finding is especially pertinent given recent international calls for the development and implementation of a comprehensive Earth observation system ( see http://iwgeo.ssc.nasa.gov/documents.asp?s=review) that includes the use of novel techniques for monitoring and understanding ocean and climate interactions to address strategic environmental and societal needs.

Preliminary Development and Evaluation of Fiber-Optic Chemical Sensors

This paper could be consider seminal in the Civil Engineering field as it describes the first application of these sensors to a complex durability and management issue. For this reason it is potentially controversial as it requires Civil Engineers to re-evaluate the nature and scale of durability testing.

High-Frequency Ultrasound Assessment of the Murine Heart From Embryo Through to Juvenile

Aim: The aim of this study is to assess the murine heart of normal embryos, neonates, and juveniles using high-frequency ultrasound. Methods: Diastolic function was measured with E/A ratio (E wave velocity/A wave velocity) and isovolumetric relaxation time (IRT), systolic function with isovolumetric contraction time (ICT), percentage fractional shortening (FS%), percentage ejection fraction (EF%). Global cardiac performance was quantified using myocardial performance index (MPI). Results: Isovolumetric relaxation time remained stable from E10.5 to 3 weeks. Systolic function (ICT) improved with gestation and remained stable from E18.5 onward. Myocardial performance index showed improvement in embryonic lift (0.82-0.63) and then stabilized from 1 to 3 week (0.60-0.58). Percentage ejection fraction remained high during gestation (77%-69%) and then decreased from the neonate to juvenile (68%-51%). Conclusion: The ultrasound biomicroscope allows for noninvasive in-depth assessment of cardiac function of embryos and pups. Detailed physiological and functional cardiac function readouts can be obtained, which is invaluable for comparison to mouse models of disease.

Prospective Evaluation of Clinical and Ultrasound Findings in Ankle Disease in Juvenile Idiopathic Arthritis: Importance of Ankle Ultrasound

Objective. To prospectively compare clinical examination of the ankle structures with ultrasound (US) findings. Methods. In 42 children with juvenile idiopathic arthritis (JIA; 25 girls, 17 boys, mean age 11.3 yrs, range 2.3–22.3 yrs), a total of 61 swollen/painful ankles were assessed clinically and ultrasonographically. Accurate clinical examination of the entire ankle joint was performed, focusing especially on 3 regions — tibiotalar joint and medial and lateral tendons. Clinical and US findings were both scored 0–3 (normal-severe). Results. US demonstrated no signs of tibiotalar joint effusion in 14 out of 43 ankles considered clinically involved. For the medial tendons, US showed tenosynovitis in 13 ankles out of 31 thought to be clinically normal; and for the lateral tendons, of the 19 deemed to be clinically involved, less than 50% had involvement on US. Very poor agreement was observed comparing the clinical and US scores for the 3 regions: tibiotalar joint, kappa = 0.3; medial tendons, kappa = 0.24; lateral tendons, kappa = 0.25. With regard to other ankle structures, only 39% of the subtalar (talocalcaneal) joints considered clinically involved were deemed abnormal on US. Finally, of the 10 ankles with talonavicular US effusion, only 2 were considered clinically involved. Conclusion. Using US findings as the “gold standard,” clinical examination of the ankle in children with JIA was found to be inadequate in identifying the structures involved. US assessment prior to any glucocorticoid injection should be considered to improve the outcome. A prospective study comparing the outcome following clinical- versus US-guided ankle joint injection should be undertaken, to confirm our findings.

Ankle disease in juvenile idiopathic arthritis: ultrasound findings in clinically swollen ankles

The ankle joint is frequently involved in juvenile idiopathic arthritis (JIA), but it is unclear whether this is predominantly due to synovitis, tenosynovitis, or both. We performed clinic-based ultrasound examination to assess the prevalence of synovitis and tenosynovitis in children with JIA felt clinically to have active inflammatory disease of the ankle.

Colour Doppler ultrasound of the ocular circulation in patients with systemic lupus erythematosus identifies altered microcirculatory haemodynamics

We assessed whether quantitative analysis of Doppler flow velocity waveforms is able to identify subclinical microvascular abnormalities in SLE and whether eigenvector analysis can detect changes not detectable using the resistive index (RI). Fifty-four SLE patients with no conventional cardiovascular risk factors, major organ involvement or retinopathy were compared to 32 controls. Flow velocity waveforms were obtained from the ophthalmic artery (OA), central retinal artery (CRA) and common carotid artery (CA). The waveforms were analysed using eigenvector decomposition and compared between groups at each arterial site. The RI was also determined. The RI was comparable between groups. In the OA and CRA, there were significant differences in the lower frequency sinusoidal components (P <0.05 for each component). No differences were apparent in the CA between groups. Eigenvector analysis of Doppler flow waveforms, recorded in proximity of the terminal vascular bed, identified altered ocular microvascular haemodynamics in SLE. Altered waveform structure could not be identified by changes in RI, the traditional measure of downstream vascular resistance. This analytical approach to waveform analysis is more sensitive in detecting preclinical microvascular abnormalities in SLE. It may hold potential as a useful tool for assessing disease activity, response to treatment, and predicting future vascular complications.