Structural refinement and electrochemical properties of one dimensional (ZnO NRs)1-x(CNs )x functional hybrids for serotonin sensing studies

Herein, the efficient serotonin (5-HT) sensing studies have been conducted using the (ZnO NRs) 1−x(CNs) x nanocomposites (NCs) having appropriate structural and electrochemical properties. Initially, the different compositions of ZnO nanorods (NRs), with varying content of carbon nanostructures (CNs=MWCNTs and RGO), are prepared using simple in-situ wet chemical method and thereafter these NCs have been characterized for physico-chemical properties in correlation to the 5-HT sensing activity. XRD Rietveld refinement studies reveal the hexagonal Wurtzite ZnO NRs oriented in (101) direction with space group ‘P6 3mc’ and both orientation as well as phase of ZnO NRs are also retained in the NCs due to the small content of CNs. The interconnectivity between the ZnO NRs with CNs through different functional moieties is also studied using FTIR analysis; while phases of the constituents are confirmed through Raman analysis. FESEM images of the bare/NCs show hexagonal shaped rods with higher aspect ratio (4.87) to that of others. BET analysis and EIS measurements reveal the higher surface area (97.895 m 2/g), lower charge transfer resistance (16.2 kΩ) for the ZCNT 0.1 NCs to that of other NCs or bare material. Thereafter, the prepared NCs are deposited on the screen printed carbon electrode (SPCE) using chitosan as cross-linked agent for 5-HT sensing studies; conducted through cyclic voltammetry (CV) and square wave voltammetry (SWV) measurements. Among the various composites, ZCNT0.1 NCs based electrodes exhibit higher sensing activity towards 5-HT in accordance to its higher surface area, lower particle size and lower charge transfer resistance. SWV measurements provide a wide linear response range (7.5–300 μM); lower limit of detection (0.66 μM), excellent limit of quantification (2.19 μM) and good reproducibility to ZCNT 0.1 NCs as compared to others for 5-HT sensing studies

Synthesis of Ni2+ ion doped ZnO-MWCNTs nanocomposites using an in situ sol-gel method : an ultra sensitive non-enzymatic uric acid sensing electrode material

Nickel (Ni2+) ion doped zinc oxide-multi-wall carbon nanotubes (NZC) with different composition ratios of MWCNTs (from 0.01 to 0.1 wt%) are synthesized through anin situsol-gel method. The synthesized NZC nanocomposites (NCs) are used as electrode materials with glassy carbon electrodes (GCEs) for electrochemical detection of uric acid (UA). The cyclic voltammogram of the representative NZC 0.1 modified GCE (NZC 0.1/GCE) revealed the highest electrochemical sensing activity towards the oxidation of UA at 0.37 V in 0.2 M phosphate buffer solution (PBS) having pH 7.4 ± 0.02. The limit of detection (LOD) and limit of quantification (LOQ) for the NZC 0.1/GCE are determined to be 5.72 nM and 19.00 nM (S/N = 3) respectively, which is the lowest compared to the literature values reported for enzymatic and non-enzymatic detection techniques. The synergistic effect of NZC 0.1 NCs is proposed as one of the factors for the enhanced electrochemical oxidation of UA complemented by the phase, lattice parameters, functional groups, morphology, elemental compositions, types of bonding and specific surface area with pore size ascertained using various techniques. The synthesized NZC 0.1 NCs are further proposed as selective electrode materials for the electrochemical detection of UA as authenticated further by performing interference tests with other metabolites such as ascorbic acid (AA), dopamine (DA) andd-glucose. The optimized electrochemical studies are further adopted for sensing of UA from human excretion samples using NZC 0.1 NCs

TRANSILLUMINATION IMAGING FOR EARLY SKIN CANCER DETECTION

Frequent screening of suspicious skin pigmentations is of paramount importance since, at an early stage, skin cancer has a high cure rate and, in most cases, requires a simple treatment. In this paper, we present a new methodology for early detection of skin cancer based on the analysis of a pair of cross-polarization and side-transillumination images to examine surface pigmentation and vascularization characteristics of a lesion. Initially, the two images are automatically segmented by three separate procedures, and then the most accurate results are selected by a scoring stage. Finally, classification of the lesion as malignant or benign is accomplished by measuring the amount of hypervascularity around the pigmented area. When applied to a set of skin lesions, the two-stage methodology provided a 93.3 % success rate of correct image segmentation, and it was able to classify correctly lesions as malignant or benign with 86.9 % accuracy. The automatic segmentation procedure was validated against expert manual segmentation, whereas the final lesion classification was validated against findings from pathology. These results provide strong support for the importance of transillumination imaging in the early detection of skin cancer

Design of POSICAM: A high resolution multislice whole body positron camera

A high resolution (6mm), multislice (21) whole body positron camera has been designed with innovative detector and septa arrangement for 3-D imaging and tracer quantitation. An object of interest such as the brain and the heart is optimally imaged by the 21 simultaneous image planes which have 12 mm resolution and are separated by 5.5 mm to provide adequate sampling in the axial direction. The detector geometry and the electronics are flexible enough to allow BaF/sub 2/, BGO, GSO or time of flight BaF/sub 2/ scintillators. The mechanical gantry has been designed for clinical applications and incorporates several features for patient handling and comfort. A large patient opening of 58 cm diameter with a tilt of +-30/sup 0/ and rotation of +-20/sup 0/ permit imaging from different positions without moving the patient. Multiprocessor computing systems and user-friendly software make the POSICAM a powerful 3-D imaging device. 7 figs