Raman microscopy in the diagnosis and prognosis of surgically resected nonsmall cell lung cancer

The main curative therapy for patients with nonsmall cell lung cancer is surgery. Despite this, the survival rate is only 50%, therefore it is important to more efficiently diagnose and predict prognosis for lung cancer patients. Raman spectroscopy is useful in the diagnosis of malignant and premalignant lesions. The aim of this study is to investigate the ability of Raman microscopy to diagnose lung cancer from surgically resected tissue sections, and predict the prognosis of these patients. Tumor tissue sections from curative resections are mapped by Raman microscopy and the spectra analzsed using multivariate techniques. Spectra from the tumor samples are also compared with their outcome data to define their prognostic significance. Using principal component analysis and random forest classification, Raman microscopy differentiates malignant from normal lung tissue. Principal component analysis of 34 tumor spectra predicts early postoperative cancer recurrence with a sensitivity of 73% and specificity of 74%. Spectral analysis reveals elevated porphyrin levels in the normal samples and more DNA in the tumor samples. Raman microscopy can be a useful technique for the diagnosis and prognosis of lung cancer patients receiving surgery, and for elucidating the biochemical properties of lung tumors. (C) 2010 Society of Photo-Optical Instrumentation Engineers. [DOI: 10.1117/1.3323088]

Pterin detection using surface-enhanced Raman spectroscopy incorporating a straightforward silver colloid-based synthesis technique

Optical techniques toward the realization of sensitive and selective biosensing platforms have received considerable attention in recent times. Techniques based on interferometry, surface plasmon resonance, and waveguides have all proved popular, while spectroscopy in particular offers much potential. Raman spectroscopy is an information-rich technique in which the vibrational frequencies reveal much about the structure of a compound, but it is a weak process and offers poor sensitivity. In response to this problem, surface-enhanced Raman scattering (SERS) has received much attention, due to significant increases in sensitivity instigated by bringing the sample into contact with an enhancing substrate. Here we discuss a facile and rapid technique for the detection of pterins using SERS-active colloidal silver suspensions. Pterins are a family of biological compounds that are employed in nature in color pigmentation and as facilitators in metabolic pathways. In this work, small volumes of xanthopterin, isoxanthopterin, and 7,8-dihydrobiopterin have been examined while adsorbed to silver colloids. Limits of detection have been examined for both xanthopterin and isoxanthopterin using a 10-s exposure to a 12 mW 532 nm laser, which, while showing a trade-off between scan time and signal intensity, still provides the opportunity for the investigation of simultaneous detection of both pterins in solution. (C) 2011 Society of Photo-Optical Instrumentation Engineers (SPIE). [DOI: 10.1117/1.3600658]

Relationship between biomedical catheter surface properties and lubricity as determined using textural analysis and multiple regression analysis

In this study, the surface properties of and work required to remove 12 commercially available and developmental catheters from a model biological medium (agar), a measure of catheter lubricity, were characterised and the relationships between these properties were examined using multiple regression and correlation analysis. The work required for removal of catheter sections (7 cm) from a model biological medium (1% w/w agar) were examined using tensile analysis. The water wettability of the catheters were characterised using dynamic contact angle analysis, whereas surface roughness was determined using atomic force microscopy. Significant differences in the ease of removal were observed between the various catheters, with the silicone-based materials generally exhibiting the greatest ease of removal. Similarly, the catheters exhibited a range of advancing and receding contact angles that were dependent on the chemical nature of each catheter. Finally, whilst the microrugosities of the various catheters differed, no specific relationship to the chemical nature of the biomaterial was apparent. Using multiple regression analysis, the relationship between ease of removal, receding contact angle and surface roughness was defined as: Work done (N mm) 17.18 + 0.055 Rugosity (nm)-0.52 Receding contact angle (degrees) (r = 0.49). Interestingly, whilst the relationship between ease of removal and surface roughness was significant (r = 0.48, p = 0.0005), in which catheter lubricity increased as the surface roughness decreased, this was not the case with the relationship between ease of removal and receding contact angle (r = -0.18, p > 0.05). This study has therefore uniquely defined the contributions of each of these surface properties to catheter lubricity. Accordingly, in the design of urethral catheters. it is recommended that due consideration should be directed towards biomaterial surface roughness to ensure maximal ease of catheter removal. Furthermore, using the method described in this study, differences in the lubricity of the various catheters were observed that may be apparent in their clinical use. (C) 2003 Elsevier Ltd. All rights reserved.

Ancients inspire modern memory

A stencilling technique for depositing arrays of nanoscale ferroelectric capacitors on a surface could be useful in data storage devices.

The design and performance of a 2.5-GHz telecommand link for wireless biomedical monitoring

This paper details the implementation and operational performance of a minimum-power 2.45-GHz pulse receiver and a companion on-off keyed transmitter for use in a semi-active duplex RF biomedical transponder. A 50-Ohm microstrip stub-matched zero-bias diode detector forms the heart of a body-worn receiver that has a CMOS baseband amplifier consuming 20 microamps from +3 V and achieves a tangential sensitivity of -53 dBm. The base transmitter generates 0.5 W of peak RF output power into 50 Ohms. Both linear and right-hand circularly polarized Tx-Rx antenna sets were employed in system reliability trials carried out in a hospital Coronary Care Unit, For transmitting antenna heights between 0.3 and 2.2 m above floor level, transponder interrogations were 95% reliable within the 67-m-sq area of the ward, falling to an average of 46 % in the surrounding rooms and corridors. Overall, the circular antenna set gave the higher reliability and lower propagation power decay index.

Recent developments in X-UV optics and X-UV diagnostics

Metrology of XUV beams (X-ray lasers, high-harmonic generation and VUV free-electron lasers) is of crucial importance for the development of applications. We have thus developed several new optical systems enabling us to measure the optical properties of XUV beams. By use of a Michelson interferometer working as a Fourier-transform spectrometer, the line shapes of different X-ray lasers have been measured with a very high accuracy (Deltalambda/lambdasimilar to10(-6)). Achievement of the first XUV wavefront sensor has enabled us to measure the beam quality of laser-pumped as well as discharge-pumped X-ray lasers. A capillary discharge X-ray laser has demonstrated a very good wavefront allowing us to achieve an intensity as high as 3x10(14) W cm(-2) by focusing with a f=5 cm mirror. The sensor accuracy has been measured using a calibrated spherical wave generated by diffraction. The accuracy has been estimated to be as good as lambda/120 at 13 nm. Commercial developments are underway. At Laboratoire d'Optique Appliquee, we are setting up a new beamline based on high-harmonic generation in order to start the femtosecond, coherent XUV optic .

Moisture-Activated Rheological Structuring of Nonaqueous Poloxamine–Poly(Acrylic Acid) Systems Designed as Novel Biomedical Implants

This study reports the formulation/characterisation of novel polymeric platforms designed to behave as low-viscosity systems in the nonaqueous state, however, following uptake of aqueous ?uids, exhibit rheological structuring and mucoadhesion. The rheological/mechanical and mucoadhesive properties of platforms containing poly(acrylic acid) (PAA, 1%, 3%, 5%, w/w) and poloxamines (Tetronic 904, 901, 704, 701, 304), both in the absence and presence of phosphate buffered saline (PBS, pH 7.4) are described. With the exception of Tetronic 904, all formulations exhibited Newtonian ?ow in the nonaqueous state, whereas, all aqueous formulations displayed pseudoplastic ?ow. The consistency and viscoelastic properties were dependent on the concentrations of PAA and PBS and Tetronic grade. PBS signi?cantly increased the consistency, viscoelasticity and mucoadhesion, reaching a maximum at a de?ned concentration of PBS that was dependent on PAA concentration and Tetronic grade. Formulations containing Tetronic 904 exhibited greatest consistency and elasticity both prior to and after dilution with PBS. Increasing PAA concentration enhanced the mucoadhesive properties. Prolonged drug release of metronidazole was observed from formulations containing 10% (w/w) PBS, 3% and, particularly, 5% (w/w) PAA. It is suggested that the physicochemical properties of formulations containing 3% or 5% (w/w) PAA and Tetronic 904, would render them suitable platforms for administration to body cavities.

Designed ultrafast optical nonlinearity in a plasmonic nanorod metamaterial enhanced by nonlocality

All-optical signal processing enables modulation and transmission speeds not achievable using electronics alone(1,2). However, its practical applications are limited by the inherently weak nonlinear effects that govern photon-photon interactions in conventional materials, particularly at high switching rates(3). Here, we show that the recently discovered nonlocal optical behaviour of plasmonic nanorod metamaterials(4) enables an enhanced, ultrafast, nonlinear optical response. We observe a large (80%) change of transmission through a subwavelength thick slab of metamaterial subjected to a low control light fluence of 7 mJ cm(-2), with switching frequencies in the terahertz range. We show that both the response time and the nonlinearity can be engineered by appropriate design of the metamaterial nanostructure. The use of nonlocality to enhance the nonlinear optical response of metamaterials, demonstrated here in plasmonic nanorod composites, could lead to ultrafast, low-power all-optical information processing in subwavelength-scale devices.