Green synthesis of silver nanoparticles from waste Vigna mungo plant and evaluation of its antioxidant and antibacterial activity

The development of nanoparticles by using bioresources has become a good practice recently to avoid hazardous chemicals and processes. The present study reports the synthesis of silver nanoparticles by using an alkaline food additive prepared from Vigna mungo plant waste ash. This food additive called “Khar” is very popular in Assam, a North-Eastern state of India. This additive was used as the reducing and stabilizing agent for the synthesis of silver nanoparticles which were then characterized using TEM, XRD, UV–visible spectroscopy, DLS and zeta potential study, FESEM, and EDX. To study the antioxidant activity of the silver nanoparticle and plant waste ash extract, phytochemical analysis was done using standard methods. The quantitative phytochemical anal ysis revealed the presence of phenolic and flavonoid compounds in the aqueous extract of the Vigna mungo ash which was responsible for the strong antioxidant activity of both ash extracts ­(IC50 = 27.83 µg/mL) and silver nanoparticles ­(IC50 = 13.74 µg/mL). The agar well diffusion method was used for the analysis of the antibacterial activity of silver nanoparticles which showed remarkable antibacterial activity against both the gram-positive bacteria (Staphylococcus aureus) and gram-negative bacteria (Escherichia coli) respectively. Thus, the study reveals the utility of a traditional food additive made of Assam in the synthesis of silver nanoparticle with notable antioxidant and antibacterial activity.

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Colloids and Surfaces C: Environmental Aspects

(Abstract not found)

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Narirutin. A flavonoid found in citrus fruits modulates cell cycle phases and inhibits the proliferation of hormone-refractory prostate cancer cells by targeting hyaluronidase

(Abstract not found)

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I. I NTRODUCTION N ONLINEAR systems with partially or completely unknown dynamics, arising from unmodeled

This letter addresses prescribed performance control (PPC) for uncertain multi-input multi-output (MIMO) nonlinear systems subject to saturated and coupled inputs. The proposed controller requires no model parameter knowledge and is of low implementation complexity, i.e., no regressors, observers, or approximation structures are utilized. We derive explicit feasibility conditions linking saturation levels to performance envelopes, system parameters, gains as well as disturbances, and effectively extend the low-complexity results on prescribed performance control with input saturation to the case of input coupling. Boundedness of all closed-loop signals and prescribedperformance tracking are established. A planar two-link manipulator simulation validates the appro ach.

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I. I NTRODUCTION C ONTACTORS, as a basic electrical apparatus, are widely used in many applications, such as motor systems [1] and power systems [2] . With the development of the smart grid and energy-saving approaches, the demand for excellent contactor performance is gradually increasing, especially for low power consumption. The operation of contactors involving highpowerconsumptionimpactsthepowerqualityofthecontrol power supply and reduces the power efficiency of the industrial

The actuator drivers are rarely transplanted among different contactors because the self-tuning of excitation control parameters either takes a long time or is relevant to many contactor structural parameters. An adaptive actuator driver for ac contactors is proposed based on the coil impedance estimation and mathematical equations between the coil impedance and excitation control parameters. The coil impedance estimation and its error correction are established through the voltage balance equation when the contactor is in the open position. The coil inductance estimation is established through the zero-state response equation when the contactor is in the closed position. The mathematical equations are established based on the equivalence of the electromagnetic for ce under different excitation methods, the power consumption model, and the control system’s transfer function. A geometric feature of the flux linkage waveform is established to identify whether a contactor is in the closed position and realize the selftransition of the driver’s working state. Then, self-tuning regulators for the excitation control parameters are realized. This driver has a plug-and-play function for ac contactors and can reduce the contactor’s power consumption. This driver may be prospectively reduced to a chip.

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Presumed incipient choroidal melanoma: proposed diagnostic criteria and management

Aims To propose diagnostic criteria for a presumed incipient choroidal melanoma based on tumour growth rate and tumour doubling time (TDT) and to describe management of such tumours with transpupillary thermotherapy (TTT). Methods Retrospective interventional case series of nine consecutive presumed incipient uveal melanomas diagnosed and treated with TTT in 2010–2017. Growth rate in mm/year and per cent/year in largest basal diameter (LBD) and TDT were compared with published data for uveal melanomas and growing naevi that did not transform to melanoma under long-­term follow-­up. Results The median LBD and thickness were 1.6 mm (range 0.9–2.3) and 0.20 mm (range 0.15–0.29), respectively. The median age was 57 years (range 47–78). Seven tumours were classified as de novo m elanomas and two as transformed naevi. The median time from first observation to diagnosis was 3.3 years (range 2.2–7.3), LBD growth rate 0.25 mm/year (range 0.11–0.72) and 34 per cent/year (range 10–1437), and TDT 609 days (range 97–1612). The estimates matched those reported for uveal melanoma (median TDT 521 days, 90th percentile 2192) and exceeded those for growing naevi (median growth rate 0.04 mm/year, 90th percentile 0.12; 1.1 per cent/year, 90th percentile 2.6). The predicted median age at de novo appearance was 51 years (range 32–63). No tumour grew after TTT during a median follow-­up of 2.1 years (range 0.6–8.7). Conclusions In this series, relative growth rate and

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Cemento-­ossifying fibroma of the posterior mandible

(Abstract not found)

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