R Nagarajan

A common spice, Syzygium aromaticum is widely known as clove; this is the flower bud of a tree that belongs to the Myrtaceae family. With its origin in Indonesia, it has found application in medicine in Asian and western countries. It has taken a prominent place in alternative medicine and as a food flavoring agent. The clove buds contain several compounds of interest, such as eugenol, eugenyl acetate, trans-caryophyllene, β-caryophyllene, polyphenols, tannins, and triterpenoids. These rich bioactives make it a sought-after home remedy for illness from dental complications to inflammation of several kinds. The active compounds have been effectively extracted using solvents such as water, ethanol, and methanol. These compounds contribute to the fragrance and antioxidant, antibacterial, and antifungal properties, which underpin its enormous applications in the food and flavoring industries. Despite these beneficial properties, they may elicit some adverse reactions when administered at higher concentrations. Clove buds and their extracts containing active compounds, or the standalone compounds such as eugenol and oleoresins, have been approved by the Food and Drug Administration (FDA) as a food additive. The phenolics-rich fraction of clove has been reported to show no adverse effects on Wistar rats at 1000mg/kg body weight/day. A few research reports are indicative of the extract affecting the reproductive indices in animal models. However, the studies related to the toxic exposure of clove extracts are limited due to the highly variable nature of the sources and their constituents extracted thereafter. This work discusses the toxicity of different types of clove extracts.

In this experimental work, three different types of nanofluids were evaluated for their stability using dynamic light scattering and particle morphological study using scanning electron microscopy. The nanofluids used in this study are zinc oxide (ZnO) nanoparticle in water and 5 wt% polyvinylpyrrolidone (PVP) as a dispersant, and ZnO with polyethylene glycol (PEG 600) and CuO with PEG 600 with 5 wt% PVP at different concentration of 0.1, 0.3 and 0.5 wt%. Thermal and electrical conductivities were determined by KD-2 Pro® and PC 700 Eutech®. The result shows better enhancement in the thermal and electrical conductivity in the ZnO+PVP+Water system, followed by the CuO+PVP+PEG and ZnO+PEG systems. The highest percentage enhancement in thermal conductivity found to be 35.5% of ZnO+ PVP+water systems. The thermal conductivity results were compared with a theoretical model and show good agreement with results predicted by the model. The proposed model of Nan et al. (1997) is based on a hypothesis regarding the physical mechanism in heat transfer for nanofluids. This study is expected to form the basis for the development of nanofluid-based technologies with PEG as the primary additive in the upstream oil and gas industry especially in gas hydrates and drilling technology.

The Mentha arvensis essential oil, due to its poor aqueous solubility and the lack of a proper formulation, has found very limited clinical use. In this study, Mentha oil nanoemulsion was formulated using ultrasonication of Mentha oil with tween 80 and water, and its role as a potential anticancer and antibacterial agent was evaluated. Surfactant concentration and emulsification time play an important role in optimization of nanoemulsions. A clear and stable nanoemulsion (M3C) with a droplet diameter in the nanometric range was obtained in a sonication time of 20 min. The anticancer activity of the nanoscale-based Mentha oil emulsion was evaluated by various cell culture techniques including MTT, colony formation assay, and Annexin V apoptotic assay. The result of Annexin V-FITC assay, marker of apoptosis, clearly displays the induction of early apoptosis in anaplastic/aggressive thyroid cancer cell line (HTh-7). Also, M3C demonstrated antibacterial activity against Staphylococcus aureus (ATCC 29213). In addition, interaction of M3C with the pathogen caused structural changes in the lipid cell membrane of pathogen, with increased leakage of cytoplasmic contents as assessed through the absorbance value of 260 nm. Agar well diffusion, along with membrane integrity analysis, also validated the antimicrobial activity. The results of this translational research are expected to substantiate the potential for use of Mentha oil in therapeutic studies, as well as in anticancer and antibacterial therapy.

Carbon dioxide emission from anthropogenic sources plays a major role in global warming and climate change. Conventional amine-based carbon capture is matured technology that has limitations on high-temperature use imposed by solvent degradation and solvent loss during CO2 stripping/regenerating solvent. The present experimental investigation involves the application of tank-type (bath-type) sonication for CO2 stripping from aqueous carbon-rich 30 wt% MEA solvent in a low temperature-controlled environment, using ultrasonic frequencies of 25 kHz (cavitation-dominant), 360 kHz (streaming-dominant), and 58/132 kHz dual-mode (combined phenomena). The results are analyzed to understand the effects of carbon loading, CO2 stripping efficiency, stripping rate, temperature profile, and energy demand. The stripping rate is higher in the low-temperature range of 6°C to 12°C for all the frequencies due to the sonication effect. In the mid setpoint range of 15°C to 30°C, the CO2 stripping rate is lower due to the combination of sonication and temperature effect, and when the temperatures increase from 40°C to 45°C, the stripping rate increases gradually due to additional temperature effect. A high cyclic capacity of 1.12 mol CO2/kg. was observed for 360 kHz frequency at 12°C. The lowest energy of 3.94 kJ/mol CO2 was achieved for 360 kHz at a setpoint of 12°C. Factors such as sonication frequency, CO2 loading (mol CO2/mol soln.), temperature, and nominal power of ultrasonics play an important role in determining the sensible energy required for CO2 stripping. Specifically, CO2 stripping at the low temperature set point of 6°C and 12°C is found to be promising in all frequencies, indicating that CO2 stripping is primarily promoted by sonication, rather than by temperature.

Introduction: Plants have always been a significant source of natural active components with biological properties. Celery seed oil (extracted from Apium graveolens) has several potential applications, but its therapeutic uses in the form of nanoemulsion formulation need to be investigated further in order to meet the demand in cancer treatment, and to alleviate the prevailing crisis arising from increased antimicrobial resistance. Methods: The therapeutic potential of celery seed oil was investigated through the formulation and testing of a nanoemulsion developed with Tween 80 (a non-ionic surfactant) and the utilization of an ultrasonication technique. Anticancer and apoptotic properties of the formulation were evaluated through MTT and Annexin V-FITC assays. The clonogenic assay aided in the identification of the antiproliferative properties of the formulation on oral squamous cell carcinoma. The antimicrobial study was supported by agar well diffusion assay, membrane integrity test and scanning electron microscopy. Results: Experiments identified relevant parameters, including optimal surfactant concentration and emulsification time. GC-MS analysis identified various components in the celery oil, but not their biological activities. A sonication time of 20 min resulted in a droplet diameter of 23.4 ± 1.80 nm. The IC50 concentration of the optimal nanoemulsion formulation against SAS cells was 1.4 µL/mL. At this concentration, cell proliferation was significantly reduced through inhibition of the anchorage-independent cell growth by disrupting colony formation and inducing cell death (apoptosis) of cancer cells. The nanoemulsion was also treated with a microbial suspension of S. aureus, and displayed antibacterial properties through lipid membrane fusion, causing cytoplasmic leakage as verified through agar well diffusion and membrane permeability assays. Scanning electron microscopy revealed complete distortion of the bacterial pathogen. Conclusion: The results in this study present celery as a possible constituent for cancer therapeutics and as a candidate for aggressive, yet safe cancer treatment. The celery-based nanoemulsion has the potential to act as a key alternative to standard antibiotic therapy.

We introduce molecularly charged electrospun nanofibers obtained by soft chemical treatment for the capture of particulate matter (PM). These PMs, along with certain volatile organic compounds (VOCs), pose a severe threat not only to human health but also to the environment. As the concentrations of these PMs have been steadily increasing in the Southeast Asian countries, a dire need for protection against these particles is warranted. Filtering out the polluted air using various filtration media, such as face masks and nasal filters, has been the standard method for minimizing exposure to PM. Here, we demonstrate the removal of PM and VOCs by utilizing electrospun nanofibers of polystyrene (PS) and polyacrylonitrile (PAN) with molecular charges imparted on them via chemical treatment. The chemically treated fibers were successful in capturing even particles measuring 300 nm, which are considered to be the most penetrable particles. We report a filtration efficiency of ∼93% for removing such particles, which is ∼3 ± 1.5% enhancement when compared to the untreated fibers. The fibers have been subjected to extreme haze conditions (∼1413 μg m-3) of PM2.5 for a duration of 1 h, and the filtration efficiency was measured to be ∼99.01%. These fibers also possess the capability to capture model VOCs such as aniline, toluene, tetrahydrofuran, and chloroform. When PAN, PS, and their chemically treated counterparts were tested for their antibacterial activity, these filter mats had bactericidal effect on Escherichia coli, Bacillus subtilis, and Enterococcus faecalis. A nasal plug hosting these filter mats has been designed, which can offer personal protection from PM. Enhanced removal of residual particles is extremely important, and this difficult task is made possible with our approach. The efficiency of our approach is due to the charged nature of PM, especially of the smaller size regime.

Cancer is known as the most dangerous disease in the world in terms of mortality and lack of effective treatment. Research on cancer treatment is still active and of great social importance. Since 1930, chemotherapeutics have been used to treat cancer. However, such conventional treatments are associated with pain, side effects, and a lack of targeting. Nanomedicines are an emerging alternative due to their targeting, bioavailability, and low toxicity. Nanoparticles target cancer cells via active and passive mechanisms. Since FDA approval for Doxil®, several nano-therapeutics have been developed, and a few have received approval for use in cancer treatment. Along with liposomes, solid lipid nanoparticles, polymeric nanoparticles, and nanoemulsions, even newer techniques involving extracellular vesicles (EVs) and thermal nanomaterials are now being researched and implemented in practice. This review highlights the evolution and current status of cancer therapy, with a focus on clinical/pre-clinical nanomedicine cancer studies. Insight is also provided into the prospects in this regard.

In 2020, the amount of CO2 generated by coal combustion was estimated to be 15.32 Gt CO2. In a solvent-based postcombustion CO2 capture (PCCC) process, the solvent regeneration/CO2 stripping process uses thermal energy to regenerate the solvent. It has an adverse impact on the solvent’s thermal stability, besides causing a significant quantity of solvent loss and a high energy demand. In recent times, one method for PCCC cost savings has emerged: sono-assisted solvent regeneration/CO2 stripping. The present work focuses on enhancing the high-frequency ultrasound-assisted aqueous carbon-rich 30 wt % monoethanolamine (MEA) solvent regeneration/CO2 stripping process using Fe2O3 hydrophobic micronized particles (concentrations varied in the ranges of 0.005, 0.01, 0.05, 0.1, and 0.2 wt %) in a controlled-temperature environment at 12 °C using 360 kHz, 470 kHz, and 1 MHz (streaming-dominant frequencies). From the investigation, the lowest concentration (0.005 wt %) of micronized particles shows maximum enhancements of 12.29, 20.93, and 33.62%, thereby decreasing the solvent sensible energy requirements by 1.26, 2.4, and 2.9 times than without micronized particles for the tested frequencies. In addition, the observed CO2 stripping rate is much higher when compared to the case without micronized particles. The stripping efficiency is observed to be high in the initial stages of sonication (5 min).

In this letter, we demonstrate a sustainable, fast, and facile room temperature synthesis of plasmonic nanoparticles and luminescent nanoclusters of gold. The synthesis was performed using an affordable, easy to build, and robust triboelectric generator (TG). The electricity generated by the TG was transferred to the solution continuously to synthesize gold nanoclusters (AuNCs). The obtained AuNCs had extremely narrow size distributions with mean particle sizes of ∼2 nm and showed bright pink luminescence under UV light. The approach was also extended to synthesize plasmonic gold nanoparticles (AuNPs). With this method, the synthesis time could be reduced from hours to several minutes without requiring any reducing agents. Tunability in size by simple variation of synthetic conditions and the consequent change in properties make this method usable for diverse applications.

Nowadays, there is a growing interest in developing innovative and efficient ecofriendly, nontoxic, and organic supplements. As time passes, there will be an exponential rise in demand for even greener products. Green nanoemulsions are one set of healthy, green, and sustainable colloidal systems that meet these criteria and standards. As the name suggests, green nanoemulsions are nano-sized emulsions that are kinetically stable, safer, and have improved functional properties than conventional emulsions. Nanoemulsions are generally oil and water dispersed into each other, with one component serving as a medium (continuous or external phase). In contrast, the other is suspended into the medium (discontinuous or internal phase). This chapter focuses on nanoemulsion components, formulation, characterization techniques, and applications in the food and agro-based sectors. The component segment covers a broad range of prevalent trends in the food industries from flavor oils to nutraceutical lipids, available in capsules and other well-known additives such as vitamins, colorants, and sweeteners. Subsequent topics concentrate on preparing green nanoemulsions using high-energy and low-energy approaches and their characterization for physical-chemical properties, stability, and rheology. All these, together with the various applications of green nanoemulsions in food and agro-based industries and future aspects in respective fields, are also discussed and summarized in this chapter.