Search Results (5)

In the ever-advancing field of nanotechnology and nanoscience, luminescent carbon dots, or carbon quantum dots, have emerged as one of the most up-and-coming carbon-based nanomaterials in recent years due to their diverse physicochemical properties, which include low toxicity, ease of synthesis, superior photostability, excellent water solubility, high specific surface areas with ease of surface functionalization, and unique electronic and optical properties. They exhibit two-photon absorption and unique tunable fluorescence emission across a wide range of wavelengths, which can be precisely controlled by surface modifications and particle size. These characteristics have led to their widespread usage in a variety of applications, including optical/fluorescent sensing, electrochemical sensing, and energy-related fields, such as light-emitting diodes, photovoltaic supercapacitors, bioimaging, drug delivery, and antimicrobial research. Recently, focus has shifted to the green synthesis of carbon dots, with significant success achieved in this area, opening a plethora of opportunities in both basic and applied sciences. This review is a comprehensive study of milestones achieved in the area of green carbon dots. This review starts with the historical background of luminescent materials and how carbon dots/carbon quantum dots have been emerging as the stars among all luminescent nanomaterials. The challenges of conventional synthesis methods for nanoparticles are also discussed, with a detailed review of the various green synthesis processes reported to date. This section provides insights into widely accepted formation mechanisms and their influence on the shapes and sizes of CDs. In the next section, various physical properties of CDs are discussed, highlighting characteristics such as high quantum yield, photoluminescence stability, and chemical inertness, which make them exceptional nanomaterials. Last but not least, various CD-related challenges and future prospects are highlighted. Overall, this review provides details of recent developments in the area of green CDs. Full article

This essay will examine the contemporary issue of the television broadcasting of the sacred Gurbani from the Darbar Sahib to set the stage for understanding the historical context of the musical sessions (chauṅkīs) of devotional singing, followed by the process of decolonizing the musical performances in modern times, including religious aesthetics and sacred time and the processional chauṅkīs in the Darbar Sahib Complex. The continuous singing of the Guru’s hymns (Gurbani kirtan) resounds inside the Darbar Sahib (“the Divine Court”), popularly known as the Golden Temple of Amritsar. This special mode of worship consists of singing and listening to the hymns of the Guru Granth Sahib, the sacred scripture of the Sikhs. The heart of Sikh devotional experience lies in the performance of scriptural hymns in a congregational setting. Notably, different sessions of devotional singing go on day and night from 2.45 a.m. to 10.45 p.m. at the Golden Temple, following a celebrated tradition established more than four centuries ago by the Fifth Sikh Guru, Guru Arjan. Even during the four-hour period of cleaning the sanctum sanctorum at midnight, the devotees recite hymns from memory, thereby making the Darbar Sahib a unique place where vibrations of sacred sound reverberate continuously for twenty-four hours a day. Full article

The development of a non-malignant and sustainable treatment approach for eradicating mephitic organic dyes from freshwater resources is a daunting task. In a similar vein, the current work investigates the mitigation of methylene blue (MB) dye utilizing titanium dioxide nanoparticles (CS-TiO₂ NPs) synthesized using cannabis sativa (bhang) leaf extract via a greener approach. The CS-TiO₂ NPs are well characterized through XRD, FE-SEM, HR-TEM, UV-Vis spectroscopy, FTIR spectroscopy, and EDS spectroscopy. Microscopic studies confirm that the average particle size distribution of the individual particles was found to be in the range of 12.5 ± 1.5 nm, whereas the average size of the CS-TiO₂ NPs aggregates is 24.5 ± 11.5 nm. Additionally, the synthesized CS-TiO₂ NPs manifested remarkable photocatalytic degradation potential against methylene blue dye with a degradation efficiency of 98.2% and an apparent rate constant of 0.0398 min⁻¹. As a result, this research offers a green/sustainable alternative for water purification. Full article

Nanotechnology is a fast-expanding area with a wide range of applications in science, engineering, health, pharmacy, and other fields. Nanoparticles (NPs) are frequently prepared via a variety of physical and chemical processes. Simpler, sustainable, and cost-effective green synthesis technologies have recently been developed. The synthesis of titanium dioxide nanoparticles (TiO₂ NPs) in a green/sustainable manner has gotten a lot of interest in the previous quarter. Bioactive components present in organisms such as plants and bacteria facilitate the bio-reduction and capping processes. The biogenic synthesis of TiO₂ NPs, as well as the different synthesis methods and mechanistic perspectives, are discussed in this review. A range of natural reducing agents including proteins, enzymes, phytochemicals, and others, are involved in the synthesis of TiO₂ NPs. The physics of antibacterial and photocatalysis applications were also thoroughly discussed. Finally, we provide an overview of current research and future concerns in biologically mediated TiO₂ nanostructures-based feasible platforms for industrial applications. Full article

Combating antimicrobial resistance (AMR) is an on-going global grand challenge, as recognized by several UN Sustainable Development Goals. Silver nanoparticles (Ag NPs) are well-known for their efficacy against antimicrobial resistance, and a plethora of green synthesis methodologies now exist in the literature. Herein, this review evaluates recent advances in biological approaches for Ag NPs, and their antimicrobial potential of Ag NPs with mechanisms of action are explored deeply. Moreover, short and long-term potential toxic effects of Ag NPs on animals, the environment, and human health are briefly discussed. Finally, we also provide a summary of the current state of the research and future challenges on a biologically mediated Ag-nanostructures-based effective platform for alleviating AMR. Full article