Detection of adulteration of Decalepis hamiltonii Wight & Arn. with Hemidesmus indicus (L.) R. Br. by pharmacognostic, molecular DNA fingerprinting by RAPD, chemical and HPTLC studies

Hemidesmus indicus (L.) R. Br. (Apocynaceae) root is extensively used in Indian traditional systems due to its biological activities. Decalepis hemiltonii Wight & Arn. is another member from the same family resembling H. indicus and is adulterated in the herbal market. Aim of the study was to compare and evaluate the distinguishing features based on macroscopy, microscopy, powder microscopy, molecular differences in the genomic DNA by RAPD, physiochemical, phytochemical screening, TLC and HPTLC fingerprint profiling of successive extracts. Microscopically cork, cortex, phloem, xylem, medullary rays and pith; powder microscopically size and shape of the cork cells, fibre, fibre tracheids, vessels, xylem parenchyma cells were different from each other. Polymorphism (75.4 %) was found in eight primers out of 16 primers analyzed. The water soluble extractive and the hexane soluble extractive of D. hamiltonii was higher than H. indicus. Tannins, flavonoids, steroids and coumarins were present only in H. indicus and absent in D. hamiltonii. After derivatization, spots at Rf 0.88 (hexane extract), 0.81 (chloroform extract) and 0.55 (ethanol extract) in H. indicus; spots at Rf 0.22, 0.45 (chloroform extract), 0.19, 0.35, 0.58, 0.59 (ethanol extract) in D. hamiltonii were observed. This study will be helpful to find out adulteration of D. hemiltonii in place of H. indicus sold in the crude drug market and in herbal formulations

S-Nav: Safety-Aware IoT Navigation Tool for Avoiding COVID-19 Hotspots

In this article, we present a Q -learning-enabled safe navigation system - S-Nav - that recommends routes in a road network by minimizing traveling through categorically demarcated COVID-19 hotspots. S-Nav takes the source and destination as inputs from the commuters and recommends a safe path for traveling. The S-Nav system dodges hotspots and ensures minimal passage through them in unavoidable situations. This feature of S-Nav reduces the commuter's risk of getting exposed to these contaminated zones and contracting the virus. To achieve this, we formulate the reward function for the reinforcement learning model by imposing zone-based penalties and demonstrate that S-Nav achieves convergence under all conditions. To ensure real-time results, we propose an Internet of Things (IoT)-based architecture by incorporating the cloud and fog computing paradigms. While the cloud is responsible for training on large road networks, the geographically aware fog nodes take the results from the cloud and retrain them based on smaller road networks. Through extensive implementation and experiments, we observe that S-Nav recommends reliable paths in near real time. In contrast to state-of-the-art techniques, S-Nav limits passage through red/orange zones to almost 2% and close to 100% through green zones. However, we observe 18% additional travel distances compared to precarious shortest paths

Calcium deficiency in hydroxyapatite and its drug delivery applications

In this work, calcium deficient hydroxyapatites (HAPs) [Ca 10 ? x (PO 4 ) 6 (OH) 2 ] [where x = 0 ? 0.3] were synthesised by precipitation method and calcined samples were characterised by Fourier transformation infrared spectroscopy, powder X-ray diffraction, scanning electron microscopy and energy-dispersive X-ray spectroscopy techniques to check phase purity, calcium deficiency, particle size and shape. The results indicate that the structure of the HAP can tolerate a calcium deficiency up to 0.2. The calcium deficient HAP (x = 0.1) powder was found to be highly porous with a particle size below 200 nm. This powder was used as a drug delivery carrier for the drug, ciprofloxacin and sustained release of the drug in the phosphate buffer solution was investigated

One-step preparation of CaO-doped partially stabilized zirconia from fused zirconia

Abstract Partially stabilized zirconia (PSZ) replaces the widespread applications of full stabilized zirconia (FSZ) on ceramics materials and refractories materials, attributed to its excellent properties including small coefficient of thermal expansion, low thermal conductivity and good thermal shock resistance. In this work, CaO-doped partially stabilized zirconia (CaO-PSZ) was optimizedly prepared from fused zirconia through conventional roasting. Meanwhile, the effects of roasting temperature and duration time on stability properties were explored to determine the stability parameters of the prepared CaO-PSZ. Results indicated that the zirconia stability rate synchronously improved with the decrease of roasting temperature and duration time, which was attributed to that the martensitic transformation of fused zirconia with volume change plays a toughening effect, further rendering the change of zirconia stability properties. XRD patterns verified the martensitic transformation, representing by cubic ZrO₂ phase (c-ZrO₂) in raw fused zirconia was partially transformed into monoclinic ZrO₂ phase (m-ZrO₂) at 1450 °C for 4 h. Moreover, the phase transition law of fused zirconia was revealed through SEM and EDAX characterization for the raw fused zirconia and the prepared CaO-PSZ. SEM patterns showed acicular patterns of grains and round fine particles clustered at grain boundaries, indicating that CaO stabilizer precipitated on grain boundaries and rendered the crystal structure enhanced, which the result was consistent with EDAX analysis. This work can lay a significant foundation for applications of microwave heating on the preparation of partially stabilized zirconia (PSZ) from fused zirconia

The controlled preparation and stability mechanism of partially stabilized zirconia by microwave intensification

Abstract Partially stabilized zirconia (PSZ) occupies an important application portion in ceramics materials and refractories materials. In this work, calcium oxide-partially stabilized zirconia (CaO-PSZ) ceramics were prepared from fused zirconia by microwave sintering, with its microstructure and stability properties characterized by XRD and SEM. Results indicated that the heating rate, cooling rate, quenching temperature and isothermal treatment time rendered different influence on the stability properties, which was mainly ascribed to the reversible martensitic transformation of zirconia ceramics. Additionally, a mixed-phase composed by cubic phase ZrO₂ (c-ZrO₂) and monoclinic phase ZrO₂ (m-ZrO₂) appeared after fused zirconia treated by microwave sintering at 1450 °C for 2 h, indicating the formation of CaO-PSZ ceramics, which the finding was consistent with the SEM and EDAX analysis. Meanwhile, CaO stabilizer precipitated behavior at the crystal boundary, with the formation of acicular grains and fine particles, further rendering a toughening effect to CaO-PSZ ceramics. This work can provide important theoretical and practical significance for applications of microwave sintering to prepare CaO-PSZ ceramics material, even extending further applications in functional materials and structural materials

Investigations on the microwave absorption properties and thermal behavior of vanadium slag:improvement in microwave oxidation roasting for recycling vanadium and chromium

Abstract Vanadium slag contains high contents of vanadium and chromium with complex and dense structures, hence microwave heating instead of conventional methods is expected to destroy the dense structure and further to improve the extraction rate of vanadium and chromium, and exploring its dielectric properties is the prerequisite work. Microwave absorption properties and thermal behavior of vanadium slag were investigated. Results indicated that vanadium slag endowed excellent microwave absorption properties, with minimum εr′ value of 34.447 (F/M). Dielectric properties of vanadium slag varied with temperature, which changing trend was matched to the three stages of microwave heating characteristics identified by heating rates. Meanwhile, the changing process of dielectric properties also corresponded to the three processes of thermogravimetric characteristics: dehydration stage (30 °C-280 °C), oxidation decomposition of olivine phase and normal spinel phase (280 °C-650 °C), and oxidation decomposition of vanadium chromium spinel (650 °C-950 °C). Moreover, the maximum dielectric constant and highest microwave heating rate of vanadium slag both appeared at the temperature regime of 500 °C-550 °C, which was also the main temperature regime for oxidation decomposition of olivine phase and normal spinel phase in vanadium slag, demonstrating the appropriate process temperature for microwave heating technology to recycle vanadium slag

Kinetics characteristics and microwave reduction behavior of walnut shell-pyrolusite blends

Abstract Combining biomass pyrolysis with microwave heating technologies provides a novel and efficient approach for low-grade pyrolusite reduction. The microwave reduction behavior and pyrolysis kinetic characteristics of walnut shell-pyrolusite blends were explored. Results indicated the optimal reduction parameters were: reduction temperature of 650 °C, holding time of 30 min, Mbio/More of 1.8:10, and microwave power of 1200 W. The co-pyrolysis characteristics of the blends included four stages: dehydration, pre-pyrolysis, intense pyrolysis and reduction, and slow pyrolysis and reduction. Fitting analysis based on Coats-Redfern method revealed that chemical reaction was the control step of the process of reducing pyrolusite by biomass, which the finding matched to the isothermal kinetic analysis results determined through unreacted shrinking nuclear model. The activation energies and pre-exponential factors were determined at 5.62 kJ·mol⁻¹–16.69 kJ·mol⁻¹ and 0.0426 min⁻¹–0.515 min⁻¹. The work provides sound references for promoting the industrial application of the combined method on minerals reduction