Search

The development of sensitive and low-cost techniques for identifying valve dysfunction has become inevitable in the context of increasing death due to cardiac diseases. The present work attempts to propose a novel technique for cardiac auscultation based on graph theory. The sixty heart sound signals from normal heart (NMH) and with aortic stenosis (ASH) are subjected to Fast Fourier Transform (FFT) and complex network analyses. The murmur signals, a time-series signal, carry information about the blood flow through the heart, which gets exposed in the graph constructed and its features. The finer details of the murmur signal from the defective aortic valve and the normal aortic valve are reflected as the increased number of frequency components in FFT and as interconnected clusters without uncorrelated nodes in the graph of ASH. The distinction in graph features forms the basis of classification based on machine learning techniques (MLTs). When the unsupervised MLT-principal component analysis gives 86.8% total variance, the supervised MLTs-K nearest neighbor (KNN), support vector machine, and KNN subspace ensemble classifiers give 100%, 95.6%, and 90.9% prediction accuracy, suggesting its potential in remote auscultation in rural health centers. [ABSTRACT FROM AUTHOR]

This paper delves into the development of biocomposite (BC) packaging material from tapioca starch (TS), flax seed gel (FS), and Siam weed (SW) extract, considering the increased demand for sustainable, eco-friendly packaging materials. The BCs—BC1 (40 mL), BC2 (80 mL), and BC3 (120 mL), prepared by varying the concentration of SW—were subjected to morphological, structure, thermal, and optical characterisations. The BC with a fragmented, agglomerated morphology shows cellulosic peaks in the X-ray diffraction pattern, indicating the C-type crystalline structure in TS. Thermogravimetric analysis confirmed the BC's safe use up to 300 °C, with a minimal 40% weight loss. Differential scanning calorimetry plots identified heat absorption during gelatinisation, with an endothermic peak at 300 °C marking a phase transition. The Fourier transform infrared (FTIR) and UV–visible spectra revealed functional groups that attribute antibacterial potential to the BC. The optical analyses show greater absorption and fewer emissions, resulting in the increased enthalpy responsible for the microbial activities. Antibacterial studies demonstrated BC2's efficacy against Staphylococcus aureus, while the stability against humidity and the minimal weight loss underscored the BC's robust thermal stability. FTIR spectra of post-heating at 80 °C confirmed the structural integrity, positioning the BC as a promising material for eco-friendly packaging solutions. [ABSTRACT FROM AUTHOR]

The work reported in the paper addresses the thermal diffusivity (TD) tuning of the electronic sensor material polyvinylidene fluoride (PVDF). The thermal properties of electronic material were found to influence the device characteristics significantly, demanding novel techniques for TD tuning. The TD value of the carbon sources—hydroxyethyl cellulose (HC), lignin (LG), and camphor soot (CS) and their composites—were measured by the sensitive nondestructive evaluation technique—photothermal beam deflection. When the HC and LG enhanced the TD of PVDF by 237.5% and 27.5%, respectively, CS was found to lower it by 11.25%. The spectroscopic analysis revealed the variation of hydroxyl groups in the samples and suggested its prominence in deciding the TD value. The Fourier transform infrared analysis and beam deflection measurements exhibited a positive correlation between hydroxyl groups and TD, except for the composite PVDF combined with soot. In this case, the amorphous carbon in soot reduced PVDF's TD due to the heat trap mechanism of carbon allotropes. The induced variation of TD of PVDF via carbon source integration is attributed to the closure of pores in PVDF, revealed through the optical microscopic images, thereby suggesting a methodology for enhancing or reducing TD of PVDF. [ABSTRACT FROM AUTHOR]