@article {49433, title = {Fabrication and evaluation of a spatially resolved fiber-optic probe for diffuse reflectance measurement for noninvasive diabetic foot ulcer diagnosis perspective}, journal = {Optical Engineering}, volume = {63}, year = {2024}, month = {APR }, pages = {044103}, type = {Article}, abstract = {

Timely diagnosis and monitoring of wound progression or healing are key to improving the long-term outcome of diabetic foot ulcers (DFU). Diffuse reflectance spectroscopy (DRS) has the potential to noninvasively diagnose the DFU in real time, as it detects changes in local blood volume fraction and oxygenation state level that occur when tissue becomes diseased or ulcerated. Since foot soles have a thicker epidermis and deeper blood vessels/capillaries than other parts of the body, a spatially resolved fiber-optic probe (SRFP) is needed to detect the optimal spatially resolved diffuse reflectance (SRDR) signal from the local site of the ulcer for DFU diagnosis. Therefore, herein, an SRFP consisting of a linear array of seven 400-mu m fibers with detector-source (D-S) fiber separation (rho) ranging from 0.8 to 4.8 mm was designed, fabricated, tested, and evaluated for SRDR measurement from a standard reflectance plate of barium sulfate (BaSO4) and foot sole of 27 healthy human subjects. The variation in SRDR spectra for each detector and source fiber pair measured with BaSO4 was found to be less than 1.6\%. In-vivo measurements from the foot sole demonstrate that the fabricated probe has the ability to spatially resolve and distinguish the SRDR spectra from sites, namely, the fifth metatarsal, ball of great joint, calcaneum, and great toe. Experimentally and theoretically, the detector and source fiber pair of rho=1.6 and 2.4 mm were optimal for SRDR measurements from a human foot. To evaluate and validate the performance of SRFP in a context relevant to DFU diagnosis, further SRDS measurements were performed on the solid tissue phantoms that mimic the optical properties of the normal and diabetic foot sole, and their results are statistically found different. Preliminary results suggest that developed SRFP can be explored for DRS measurement from foot ulcer patients to confirm its potential clinical applicability.

}, keywords = {diabetic foot ulcer, diffuse reflectance spectroscopy, foot sole, spatially resolved fiber-optic probe, tissue phantom}, issn = {0091-3286}, doi = {10.1117/1.OE.63.4.044103}, author = {Kumar, Ajay and Hattale, Gangadhar and Pawar, Dnyandeo and Kanawade, Rajesh} } @article {49243, title = {Normal and diabetic foot sole skin mimicking tissue phantom fulfillment for spectroscopic-based DFU diagnostics perspective}, journal = {AIP ADVANCES}, volume = {14}, year = {2024}, month = {JUN }, type = {Journal Article}, keywords = {OPTICAL-PROPERTIES, STATE}, doi = {10.1063/5.0206988}, author = {Kumar, Ajay and Hattale, Gangadhar and Hinge, Sarika and Kulkarni, Gauri and Late, Dattatray J. and Kanawade, Rajesh} } @article {49882, title = {Optimisation of metallic bismuth nanoparticle supported Pt-Bi(x\%)/C hybrid electrocatalyst for cost effective and efficient hydrogen production in alkaline media}, journal = {International Journal of Hydrogen Energy}, volume = {161}, year = {2025}, month = {AUG}, pages = {150699}, type = {Article}, abstract = {

The present study employed a simple mechanochemical method followed by 24-h ultrasonication to synthesize oxide-free metallic bismuth (Bi) nanoparticles. This was further used to synthesize a Pt-Bi(x\%)/C (NC-x) hybrid electrocatalyst for the hydrogen evolution reaction in alkaline media. X-ray photoelectron spectroscopy and contact angle measurements reveal, Bi modifies the electronic structure and surface morphology of the Pt/C electrocatalyst, thus enhancing reaction kinetics and active site availability. The relative three-electrode study reveals that optimised NC-20 electrocatalyst reduces the overpotentials by 10.44 \% and enhances the current density by 53 \% compared to commercial Pt/C. The practical applicability of the NC-20 electrocatalyst was studied with the 13 cm2 single cell anion exchange membrane electrolyser. The catalyst demonstrates promising performance where the current density of NC-20//IrO2 relatively increases by 22.6 \% compared to standard Pt/ C//IrO2, and shows continuous production and stable performance when monitored for 30 h.

}, keywords = {AEM, Bismuth nanoparticles, electrocatalyst, Full cell electrolysis, hydrogen evolution reaction, water electrolysis}, issn = {0360-3199}, doi = {10.1016/j.ijhydene.2025.150699}, author = {Dokhe, Revati and Ugale, Atul and Dube, Onkar and Varpe, Vaibhav and Galave, Chaitanya and Hattale, Gangadhar and Kadam, Rutuja and Virole, Vishal and Kumar, Ajay and Husale, Sudhir and Natu, Varun and Shevate, Rahul and Kanawade, Rajesh} } @article {49954, title = {Photoluminescence decay lifetime study of hydrothermally synthesized highly porous ruthenium-silica composite for optical dissolved oxygen sensing application}, journal = {ACS Applied Nano Materials}, volume = {9}, year = {2026}, month = {JAN}, pages = {937-949}, type = {Article}, abstract = {

Pore size and surface area of photoluminescence (PL)-based transition metal composites play crucial roles in facilitating oxygen diffusion, thereby enhancing the response and sensitivity of optical dissolved oxygen (DO) sensors. In this study, we successfully applied the hydrothermal method to synthesize a porous ruthenium composite embedded in a silica matrix, demonstrating its effectiveness for optical DO sensing applications. The ruthenium-silica (Ru-Si) composites were synthesized using Ru(bpy)3 2+ and tetraethyl orthosilicate (TEOS) as precursors, with reaction temperatures ranging from 120 degrees C to 200 degrees C over a fixed duration of 4 h. The structural, morphological, and compositional characterization techniques confirmed the successful synthesis and evaluated the porosity, surface features, and chemical structure of the resulting composites. The optimized Ru-Si composite exhibited the highest porosity, characterized by a specific surface area of 996.78 m2 g- 1, and exhibited the highest decay lifetime of 8.14 mu s in deionized (DI) water, compared to other composites. Importantly, we demonstrate an excellent linear response of the synthesized Ru-Si composite to DO concentrations ranging from 2.58 to 11.16 mg L-1, with a Stern-Volmer constant of 0.12. Furthermore, a density functional theory study was conducted to investigate the electronic transitions and to elucidate the oxygen quenching mechanism of the excited Ru composite with molecular oxygen. The calculated photophysical parameters of the composite show good agreement with the experimental results. Preliminary results suggest that the synthesized Ru-Si with high pore size and surface area could be an efficient and effective composite for use in DO sensing applications.

}, keywords = {Hydrothermal method, opticalDO sensor, oxygen quenching, photoluminescent, ruthenium composite}, doi = {10.1021/acsanm.5c04307}, author = {Hattale, Gangadhar and Kadam, Rutuja and Virole, Vishal and Pandya, Rinu and Paul, Aditya and Kumar, Ajay and Shevate, Rahul and Vanka, Kumar and Saha, Avishek and Kanawade, Rajesh} }