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Surface-Enhanced Raman Spectroscopy (SERS) is a powerful surface-sensitive technique for molecular analysis. Its use is limited due to high cost, non-flexible rigid substrates such as silicon, alumina or glass and less reproducibility due to non-uniform surface. Recently, paper-based SERS substrates, a low-cost and highly flexible alternative, received significant attention. We report here a rapid, inexpensive method for chitosan-reduced, in-situ synthesis of gold nanoparticles (GNPs) on paper devices towards direct utilization as SERS substrates. GNPs have been prepared by reducing chloroauric acid with chitosan as a reducing and capping reagent on the cellulose-based paper surface at 100 °C, under the saturated humidity condition (100 % humidity). GNPs thus obtained were uniformly distributed on the surface and had fairly uniform particle size with a diameter of 10 ± 2 nm. Substrate coverage of resulting GNPs directly depended on the precursor's ratio, temperature and reaction time. Techniques such as TEM, SEM, and FE-SEM were utilized to determine the shape, size, and distribution of GNPs on paper substrate. SERS substrate produced by this simple, rapid, reproducible and robust method of chitosan-reduced, in situ synthesis of GNPs, showed exceptional performance and long-term stability, with a detection limit of up to 1 pM concentration of test analyte, R6G. Present paper-based SERS substrates are cost-effective, reproducible, flexible, and suitable for field applications., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Saurabh Kumar Srivastava reports that the SERB-National Postdoctoral Fellowship provided financial support from the Department of Science and Technology, New Delhi, India., (Copyright © 2023. Published by Elsevier B.V.)

Use of paper-based devices for affordable diagnostics is gaining interest due to unique advantages such as affordability, portability, easy disposability and inherent capillarity. As capillary transportation is an integral component of paper-based devices, low sample volume with faster measurement becomes an additional advantage. We have developed a simple, paper-based microfluidic device suitable for measuring the viscosity of Newtonian fluids as well as a few non-Newtonian fluids with sample volume as little as 12-20 μL. The results could be obtained much faster than the conventional methods. A comparative analysis of the results obtained with our paper-based viscometer and with that of the conventional Ostwald viscometer shows a correlation coefficient greater than 0.99. Apart from viscosity measurement, the paper-based devices were tested for protein denaturation and polymer molecular weight determination. Our results show that the paper-based viscometer could be a potential alternative for the conventional viscometers in the viscosity range from 0.9 cP up till ∼40 cP, with added benefits in terms of time, cost and low sample volume requirement., (Copyright © 2018 Elsevier B.V. All rights reserved.)

To assess the medico social demographics of acute myocardial infarction (AMI) in our community we studied 609 patients presenting between January 2008 to December 2008 with a detailed questionnaire in four centres of UP. Medical attention was sought late (> 6 hours) in 316 (51.6%), thrombolysis was obtained in 45.2% (275) and presentation was atypical in 16.3% (99). 36.2% (221) had pre-monitory symptoms of which 68% (150) ignored the same while of 32% (71) who did seek medical attention 47.9% (37) were brushed away as non-cardiac in origin. 20.3% (46/226) of hypertension, 23.2% (43/185) of diabetes and 83.4% (91/109) of hyperlipidaemia was diagnosed post event. We conclude that at least half of patients with AMI do not get definitive therapy, at least one in 10 patients do not have the classical symptoms, reasonable proportion are unaware of their risk factors, and a good majority have pre-monitory symptoms which get overlooked., (Copyright © 2012 Cardiological Society of India. Published by Elsevier B.V. All rights reserved.)