Synergistic integration of ZrO2-enriched reduced graphene oxide-based nanostructures for advanced photodegradation of tetracycline hydrochloride.

The escalating demand for the antibiotic drug tetracycline hydrochloride (TCH) contributes to an increased release of its residues into land and water bodies, which poses risks to both aquatic life and human health. Therefore, it is precedence to effectively degrade TCH residues to protect environment from their long-term impacts. In this aspect, the present study entails the synthesis of zirconia (ZrO2) nanostructures and focuses on the enhancement in the catalytic performance of ZrO2 nanostructures by employing reduced graphene oxide (RGO) as a solid support to synthesize ZrO2-enriched RGO-based photocatalysts (ZrO2-RGO) for the degradation of TCH. The study delves into comprehensive spectroscopic and microscopic investigations and their photodegradation assessments. Powder XRD and HR-TEM studies depicted the phase crystallinity and also displayed uniform distribution of ZrO2 nanostructures with spherical morphology within ZrO2-RGO. This corresponds to high surface-to-volume ratios, providing a substantial number of active sites for light absorption and generation of e--h+ pairs. Moreover, the heterojunctions created between RGO and ZrO2 nanostructures promoted the interspecies electron transfer which prolonged the recombination time of e- and h+ than pure ZrO2 nanostructures, accounted for enhanced degradation of TCH using ZrO2-RGO. The photocatalytic activity of as-synthesized materials were examined under visible and UV light irradiation. The degradation efficiency of ~ 73.82% was achieved using ZrO2-RGO-based photocatalyst with rate constant k = 0.007023 min-1 under visible-light illumination. Moreover, under UV-light, the degradation rate was explicated to be k = 0.01017 min-1 with ~ 85.56% degradation of TCH antibiotics within 180 mins. Hence, the synthesized ZrO2-enriched RGO-based photocatalysts represents a promising potential for the effective degradation of pharmaceutical compounds, particularly TCH under visible and UV-light irradiation.

Natural Pigments-Based Two-Component White Light Emitting Systems.

In this paper, a new class of two component white light emitting systems viz, JaB (java plum + beetroot) {I}, and CaB (carrot + beetroot) {II} were developed through resonance energy transfer (RET) phenomenon by using a fruit (java plum) and two vegetable (carrot and beetroot) extracts. In these white light emitting systems, java plum and carrot are the donors while beetroot is the acceptor. The primary fluorescent pigments present in the natural extracts (i.e., anthocyanin in java plum, ß-carotene in carrot, and betanin in beetroot) were responsible for the white light emission. The CIE (Commission Internationale d'Eclairage) coordinates for I and II were {0.32, 0.34} and {0.33, 0.33}, respectively, in solution phase. Interestingly, the white light emission (WLE) was also achieved in agar-agar gel medium. In gel medium, the CIE values were {0.31, 0.34} and {0.33, 0.32} for I and II, respectively. The donor-acceptor distance (r) for I and II were found to be 0.5 and 0.4 nm, respectively. Furthermore, the rate of energy transfer was also quantified with the values of 2.78 × 109 s-1 for JaB (I) and 1.02 × 108 s-1 for CaB (II) systems. The mechanistic investigation of the two white light systems was further supported by DFT studies.

Tungsten oxide nanostructures peculiarity and photocatalytic activity for the efficient elimination of the organic pollutant.

The WO3 nanostructures were synthesized by a simple hydrothermal route in the presence of C14TAB and gemini-based twin-tail surfactant. The impact of using these special shape and size directing agents for the synthesis of nanostructures was observed in the form of different shapes and sizes. The WO3 web of chains type nanostructure was obtained using C14TAB in comparison to the cube-shaped nanoparticles through twin-tail surfactant. On contrary, the twin-tail surfactant provides sustainable and controlled growth of cube shape nanoparticles of size ~ 15 nm nearly half of the size ~ 35 nm obtained using conventional surfactant C14TAB, respectively. For the detailed structural features, the Williamson-Hall analysis method was implemented to find out the crystalline size and lattice strain of the prepared nanostructures. Owing to the strong quantum confinement effect, the WO3 cube-shaped nanoparticles with an optical band gap of 2.69 eV of the prepared nanoparticles showed excellent photocatalytic efficacy toward organic pollutant (fast green FCF) compared to the web of chain nanostructures with an optical band gap of 2.66 eV. The ability of the prepared systems to decompose the organic pollutant (fast green FCF) in water was tested under visible light irradiations. The percentage degradation was found to be 94% and 86% for WO3 cube-shaped nanoparticles and WO3 web of chains, respectively. The simplicity of the fabrication method and the high photocatalytic performance of the systems can be promising in environmental applications to treat water pollution.

A highly sensitive and specific luminescent MOF determines nitric oxide production and quantifies hydrogen sulfide-mediated inhibition of nitric oxide in living cells.

The synthesis of a novel carboxylate-type organic linker-based luminescent MOF (Zn(H2L) (L1)) (named PUC2) (H2L = 2-aminoterephtalic acid, L1 = 1-(3-aminopropyl) imidazole) is reported by the solvothermal method and comprehensively characterized using single-crystal XRD, PXRD, FTIR, TGA, XPS, FESEM, HRTEM, and BET. PUC2 selectively reacts with nitric oxide (▪NO) with a detection limit of 0.08 µM, and a quenching constant (0.5 × 104 M-1) indicating a strong interaction with ▪NO. PUC2 sensitivity remains unaffected by cellular proteins or biologically relevant metals (Cu2+/ Fe3+/Mg2+/ Na+/K+/Zn2+), RNS/ROS, or H2S to score ▪NO in living cells. Lastly, we used PUC2 to demonstrate that H2S inhibition increases ▪NO production by ~ 14-30% in various living cells while exogenous H2S suppresses ▪NO production, indicating that the modulation of cellular ▪NO production by H2S is rather generic and not restricted to a particular cell type. In conclusion, PUC2 can successfully detect ▪NO production in living cells and environmental samples with considerable potential for its application in improving the understanding of the role of ▪NO in biological samples and study the inter-relationship between ▪NO and H2S.

Effect of Synthesis Methods and Conditions on Properties and Applications of Carbon Dots for the Detection of Potential Water Contaminants: A Review.

The worldwide pollution of water bodies by potential contaminants such as heavy metals, dyes, and pesticides etc. have severely affected the entire eco-system due to their toxic mobility and tough degradation in water. Consequently, there is a requirement to develop cost-competitive and easily handleable sensing materials which can detect targets sensitively and with selectivity. Among the low-cost sensory materials, carbon dots (CDs) constitute an important class of carbon nanomaterial with unique photostability, electronic and fluorescent properties. This review is an effort to comprehend the recent improvements in the sensing applications of CDs with prominence on synthetic routes, the effect of various synthesis parameters on physical properties (quantum yield, size range), detection mechanisms, and detection parameters (limit of detection, interference etc.). Particularly, the scope and progress for the detection of potential water contaminants using CDs have been explored and a holistic view of mechanisms of their detection has been included.

Holistic view of mechanisms for different types of signals generated by CDs.

Plant Growth-Promoting Attributes of Zinc Solubilizing Dietzia maris Isolated from Polyhouse Rhizospheric Soil of Punjab.

Zinc solubilizing rhizobacteria (ZSR) enhance the phyto-availability of Zn by converting its insoluble forms into usable forms that are essential for the growth and nutritional quality of crops. In the present study, a potential ZSR, hereafter referred to as strain N14, was isolated from the polyhouse rhizospheric soil of Punjab, India. The isolated rhizobacteria was found to be Gram-positive, aerobic, rod-shaped, and demonstrated a solubilization index of 63.75 on the Bunt Rovira (BR) medium. The 16S rRNA gene sequence analysis revealed that isolated strain N14 matches substantially with type strain Dietzia maris DSM 43672 T. In its ZnO broth assay, a significant amount of soluble Zn was detected along with a simultaneous decrease in pH of the broth. Ultra-performance liquid chromatography analysis revealed the release of organic acids, specifically, lactic acid and acetic acid by D. maris strain N14 which could be the reason for the decrease in broth pH. The production of indole acetic acid (29.91 µg/ml), gibberellic acid (4.72 µg/ml), ammonia (38.87 µg/ml), siderophore (0.89%), along with the release of HCN and appearance of phosphate solubilization zone (14.4 mm) with this strain suggested its possible plant growth-promoting (PGP) characteristics. Therefore, this strain was employed in the formulation of pellets which were applied for in vivo PGP studies using tomato plants. The developed bioformulated pellets showed a significant enhancement in plant growth as compared to control and vermicompost treated plants. To the best of our knowledge, this is the first report describing the Zn solubilizing and PGP characteristics of D. maris.

Comparison of diversity and zinc solubilizing efficiency of rhizobacteria obtained from solanaceous crops under polyhouse and open field conditions.

Zinc-solubilizing bacteria (Zn-SB) play a crucial role in regulating soil fertility and plant health by maintaining Zn availability in the rhizosphere. It is uncertain how the Zn-SB population fluctuates across various cultivation systems since varied land-use patterns for agricultural aims may affect microbial activity and plant development effectiveness. The current study aims to examine the Zn-SB potential of various farming systems using Solanum lycopersicum, Solanum melongena, and Capsicum annuum grown in polyhouse soil (PS) and open fields (OF). Only twenty rhizobacterial isolates from PS and two isolates from OF out of 80 showed a strong ability to solubilize Zn, which was evaluated using Atomic Absorption Spectroscopy. Bacterial strain-PS4 solubilized 253.06 ppm of ZnO and produced a high quantity of lactic acid (168.62 g/ml) and acetic acid (470.5 g/ml), whereas bacterial strain OF1 solubilized 16.02 ppm of ZnO by releasing glycolic acid (42.89 g/ml), lactic acid (22.30 g/ml), formic acid (106.03 g/ml), and acetic acid (48.5 µg/ml). Further, in vitro studies demonstrated higher production of auxin, gibberellic acid and siderophore by PS1 as compared to OF1 strain. A large diversity of Zn-SB in the soil was indicated by biochemical analysis, which revealed that isolates belonged to the families Enterobacteriaceae, Bacillaceae, Burkholderiaceae, Streptococcaceae, Paenibacillaceae, Micrococcaceae, Morganellaceae, and Dietziaceae. The isolates PS4 and OF1 were identified as Bacillus cereus and Enterobacter hormaechei, respectively, using 16S rRNA sequencing. The findings show that soil from polyhouses has a greater diversity of Zn-solubilization rhizobacteria than soil from open areas. The findings suggested a potential land-use method for enhancing crop yields by employing microorganisms and polyhouse technology, which could be useful in the future study.

Zirconia-based nanomaterials: recent developments in synthesis and applications.

In the last decade, the whole scientific community has witnessed great advances and progress in the various fields of nanoscience. Among the different nanomaterials, zirconia nanomaterials have found numerous applications as nanocatalysts, nanosensors, adsorbents, etc. Additionally, their exceptional biomedical applications in dentistry and drug delivery, and interesting biological properties, viz. anti-microbial, antioxidant, and anti-cancer activity, have further motivated the researchers to explore their physico-chemical properties using different synthetic pathways. With such an interest in zirconia-based nanomaterials, the present review focuses systematically on different synthesis approaches and their impact on the structure, size, shape, and morphology of these nanomaterials. Broadly, there are two approaches, viz., chemical synthesis which includes hydrothermal, solvothermal, sol-gel, microwave, solution combustion, and co-precipitation methods, and a greener approach which employs bacteria, fungus, and plant parts for the preparation of zirconia nanoparticles. In this review article, the aforementioned methods have been critically analyzed for obtaining specific phases and shapes. The review also incorporates a detailed survey of the applications of zirconia-based nanomaterials. Furthermore, the influence of specific phases, morphology, and the comparison with their counterpart composites for different applications have also been included. Finally, the concluding remarks, prospects and possible scope are given in the last section.

Mechanistic investigation of formation of highly-dispersed silver nanoparticles using sea buckthorn extract.

Nowadays, the greener pathways for the synthesis of nanostructures are being explored. The extracts of different parts of plantsvizleaves, stems, and roots have been investigated. However, these extracts have been prepared by simply boiling or microwaving, or sonicating the parts of plants with water. Therefore, to have deeper insight and to investigate the full potential of plant extracts, serial extraction of leaves of sea buckthorn (Hippophae rhamnoides L.) which is a medicinally important plant was attempted using the soxhlet apparatus. The as-obtained polyphenolic-rich extract was employed for the preparation of silver nanoparticles (Ag-NPs). Under optimized reaction conditionsviz60 °C temperature and 500µl of extract solution (5 mg ml-1) highly disperse spherical nanoparticles of the average size of 15.8 ± 4.8 nm were obtained. Further, the optical band gap of Ag-NPs prepared using optimized reaction conditions was found to be 2.6 eV using the Tauc equation. Additionally, to understand the reduction by the extract, kinetic studies were also carried out which suggest the predominant occurrence of pseudo-first-order reaction. Furthermore, the mechanism of formation of Ag-NPs using major components of extractvizgallic acid and catechin which were identified by HPLC were also investigated using DFT. The mechanistic investigation was performed for both the keto-enol and radical-mediated preparation of Ag-NPs. Such theoretical investigations will help in the efficient designing of greener and novel routes for the synthesis of Ag-NPs. Additionally, the prepared silver was also employed for the colorimetric detection of H2O2.

Review of Shikonin and Derivatives: Isolation, Chemistry, Biosynthesis, Pharmacology and Toxicology.

Shikonin and its derivatives, isolated from traditional medicinal plant species of the genus Lithospermum, Alkanna, Arnebia, Anchusa, Onosma, and Echium belonging to the Boraginaceae family, have numerous applications in foods, cosmetics, and textiles. Shikonin, a potent bioactive red pigment, has been used in traditional medicinal systems to cure various ailments and is well known for its diverse pharmacological potential such as anticancer, antithrombotic, neuroprotective, antidiabetic, antiviral, anti-inflammatory, anti-gonadotropic, antioxidants, antimicrobial and insecticidal. Herein, updated research on the natural sources, pharmacology, toxicity studies, and various patents filed worldwide related to shikonin and approaches to shikonin's biogenic and chemical synthesis are reviewed. Furthermore, recent studies to establish reliable production systems to meet market demand, functional identification, and future clinical development of shikonin and its derivatives against various diseases are presented.

Comprehensive review on ethnobotanical uses, phytochemistry, biological potential and toxicology of Parthenium hysterophorus L.: A journey from noxious weed to a therapeutic medicinal plant.

ETHNO-PHARMACOLOGICAL RELEVANCE: Parthenium hysterophorus L. is a noxious weed and a species of flowering plant in the Asteraceae family. It is regarded as the seventh most deadly weed in the world: harmful to both humans and livestock. It is widely known as Congress Grass or Feverfew. Despite its pitfalls, P. hysterophorus bestows medicinal effects. Although prolific in nature and difficult to control, many novel applications of this controversial herb have been discovered as an approach to manage the weed. AIM: The current review aims to compile all the ethnobotanical, phytochemistry, biological activities and utilities, clinical studies and toxicity data available on P. hysterophorus and its major chemical constituent parthenin. MATERIALS AND METHODS: Extensive literature surveyed Google search, Google scholar, Wiley online library, Elsevier, Springer, Science direct, American Chemical Society, Royal Society of Chemistry and Research Gate. RESULT: According to the study, P. hysterophorus is utilized as a traditional medicine throughout Central America and the Caribbean. It can be used to treat skin infections, dermatitis, amoebic dysentery, and as an analgesic in the treatment of muscular rheumatism. The extracts obtained from P. hysterophorus have anti-inflammatory, antioxidant, larvicidal, anti-microbial, insecticidal, hypoglycaemic and anti-cancer activity. CONCLUSION: The earlier investigations confirmed that P. hysterophorus has numerous traditional and biological applications. However, the scientific data are limited in clinical and toxicological studies. Therefore, further research is required on clinical and toxicological aspects to understand the complete potential and effects of P. hysterophorus.

Exceptional antibacterial and cytotoxic potency of monodisperse greener AgNPs prepared under optimized pH and temperature.

In the present work, silver nanoparticles were prepared by using the extract of Camellia Sinensis. The extract contains phytochemicals which are mainly polyphenols acting as the natural reducing and stabilizing agents leading to the formation of uniformly dispersed and stabilized silver nanoparticles. The synthesis of silver nanoparticles was significantly influenced by the impact of the pH, as well as temperature conditions. It was found that at pH 5 and 25 °C, nanoparticles of different morphologies (spherical, polygonal, capsule) and sizes were formed. However, with the increase in temperature from 25 °C to 65 °C but at the same pH, these particles started attaining the spherical shape of different sizes owing to an increase in the reduction rate. Furthermore, for the reaction of the mixture at 65 °C, an increase in pH from 5 to 11 led to an increase in the monodispersity of spherically shaped nanoparticles, attributed to the hydroxide ions facilitated reduction. The prepared nanoparticles were investigated for their antibacterial activity using Nathan's Agar Well-Diffusion method. It was found that AgNPs prepared at pH 9 and 65 °C demonstrated strong antibacterial activity against gram-negative Escherichia coli in contrast to gram-positive Staphylococcus aureus. In reference to the cytotoxic potency, the prepared AgNPs showed clear cytotoxicity for HeLa cells and showcased a close relationship between activity and concentration as evidenced by the decrease in the percentage (100 to 30%) of metabolically active cells up to 25 µM-75 µM concentration of silver nanoparticles.

Fine CuO anisotropic nanoparticles supported on mesoporous SBA-15 for selective hydrogenation of nitroaromatics.

SBA-15 modified with APTMS (3-aminopropyl trimethoxysilane) having pore diameter (∼8 nm) has been synthesized and impregnated with 1-10 wt.% Cu using Cu(NO3)2 as a metal source followed by calcination at 350 °C. As-prepared CuO/ap-SBA-15 powder showed changes in the color from white for bare SBA-15 to light green due to formation of anisotropic CuO nanoparticles that exhibited a characteristic plasmon absorption band at 359 and 747 nm. TEM studies showed a change in the morphology of CuO NPs as a function of increased Cu loading. Moreover, well dispersed CuO nanospheres (∼5-6 nm) and nanorods (aspect ratio ∼11-20 nm) having monoclinic crystal phase were observed within the mesoporous channels of SBA-15. Elemental mapping studies confirmed uniform distribution of CuO nanoparticles on the surface of SBA-15. An increase in surface area was also observed from 694 m(2) g(-1) for SBA-15 to 762 m(2) g(-1) for 10 wt.% Cu loading probably due to the deposition of excess of CuO nanoparticles on the outer siliceous surface. The catalytic activity also increased with Cu loading and 10 wt.% CuO/ap-SBA-15 catalyst displayed the highest catalytic activity for the reduction of m-chloronitrobenzene and m-nitrotoluene with 83% and 100% selectivity for m-chloroaniline and m-aminotoluene respectively.

Sodium aluminate as catalyst for transesterification of waste mutton fat.

Sodium aluminate and its calcinied forms have been evaluated as basic catalysts for the transesterification of waste mutton fat with methanol. The decrease in catalytic activity has been observed with calcinied sodium alumiate. Fat and methanol in 1:29 molar ratio with 1.5 wt.% of sodium aluminate under reflux resulted in 97 % conversion to biodiesel in 1h 20 min. The reaction showed tolerance of additional moisture content of 1 wt.%.