Nanotechnology is a developing branch of pharmaceutical sciences wherein the particles extend in nanosizes and turn out to be more responsive when contrasted with their unique counter parts. In the ...past numerous years, the utilization of synthetic concoctions and physical strategies were in mould; however, the acknowledgment of their toxic impacts on human well-being and condition influenced serious world view for the researchers. Presently, green synthesis is the watch word for the combination of nanoparticles (NPs) by plants or their metabolites. This innovation is particularly compensating as far as decreasing the poisonous quality caused by the conventionally integrated NPs. In this review, we cover the perspectives by which metal particles can be integrated from green methods in the perspective of green methods utilized in the NPs combination. In the green strategies, plant metabolites and natural substances are utilized to orchestrate the NPs for the pharmaceutical and other applications. Some characterization methods are also reviewed along with applications of NPs.
Dendrimer as nanocarrier for drug delivery Kesharwani, Prashant; Jain, Keerti; Jain, Narendra Kumar
Progress in polymer science,
02/2014, Volume:
39, Issue:
2
Journal Article
Peer reviewed
Dendrimers are novel three dimensional, hyperbranched globular nanopolymeric architectures. Attractive features like nanoscopic size, narrow polydispersity index, excellent control over molecular ...structure, availability of multiple functional groups at the periphery and cavities in the interior distinguish them amongst the available polymers. Applications of dendrimers in a large variety of fields have been explored. Drug delivery scientists are especially enthusiastic about possible utility of dendrimers as drug delivery tool. Terminal functionalities provide a platform for conjugation of the drug and targeting moieties. In addition, these peripheral functional groups can be employed to tailor-make the properties of dendrimers, enhancing their versatility. The present review highlights the contribution of dendrimers in the field of nanotechnology with intent to aid the researchers in exploring dendrimers in the field of drug delivery.
Nanoemulsions are kinetically stable biphasic dispersion of two immiscible liquids typically stabilized by an emulsifier with droplet sizes in the range of 10–200 nm. Present work deals with the ...formulation and characterization of stable oil-in-water nanoemulsions using nonionic surfactant (Tween 40) and light mineral oil for their application in enhanced oil recovery. The stability study of the nanoemulsions formed by high energy and low energy method was accomplished by bottle testing method. The emulsions were characterized in terms of droplet size, morphology and inner structure, surface charge, interfacial tension, and rheology. Droplet sizes of 18–31 nm obtained by dynamic light scattering analysis and surface charge values above −35 mV obtained by ζ potential measurement prove the higher kinetic stability of the formed emulsions. Cryo-TEM micrographs reveal the surface morphology and inner structure of nanoemulsions. A miscibility test was performed to determine the dissolving ability of the nanoemulsions with crude oil. Measurement of interfacial tension (IFT) by pendant drop method shows a considerable reduction in IFT values with the increase of surfactant concentration and temperature, which is highly desirable for recovering trapped oil from the fine pores of the reservoirs. The viscosity of the nanoemulsions remains stable at a wide temperature (30–70 °C) range, denoting its thermal stability. The viscoelastic property of prepared nanoemulsions shows the increase of storage modulus (G′) and loss modulus (G″) with the increase in surfactant concentration and angular frequency (rad/s). Specific frequency (SF), the crossover point of G′ and G″, indicates the transition between elastic and viscous phases of nanoemulsions. A stable value of loss modulus after SF denotes better flowability of the emulsion. To test the efficiency of nanoemulsion in enhanced oil recovery, flooding experiment was performed by injection of a small pore volume of emulsion slug in a sand pack system, and an additional recovery of 28.94% was obtained after conventional water flooding.
Microporous zeolites and nanoporous materials are important from an academic and industrial research perspective. These inorganic materials have found application as catalysts in several industrial ...processes in oil refinery, petro-chemical reactions, fine chemicals, speciality, drug discovery and pharmaceutical synthesis, exhaust emission control for stationary and mobile engines and industrial wastewater treatment. The reasons for their versatile applications in several industrial processes are their unique properties of microporous zeolites and nanoporous materials such as uniform pores, channel systems, shape selectivity, resistance to coke formation, thermal and hydrothermal stability. Furthermore, the possibility to tune the amount and strength of Brønsted and Lewis acid sites and their crystal size, as well as the possibility of modification with transition and noble metals, are key to their success as efficient, high selectivity and stable catalysts.
Kinetically stable nanoemulsion with droplet size <500 nm has emerged as an advanced material in wide industrial applications because of its unique structural and physicochemical properties. ...Nanoemulsions are stabilized by surfactants or emulsifiers by lowering the interfacial tension (IFT) between the dispersed and continuous phases to an ultra-low value. In the present study, surfactants are screened based on their ability to lower the IFT values for proper formulation of stable nanoemulsion. The critical micelle concentration (CMC) of surfactants obtained from the interfacial tension-concentration isotherm curve (IFCV) was used to evaluate surface excess concentration (Гmax), minimum surface area per molecule (Amin), adsorption efficiency (pC20), surface tension at CMC (γCMC), effectiveness of adsorption (Πcmc) along with thermodynamic parameters (ΔGmic and ΔGads). The experimental results of thermodynamic parameters reveal that adsorption phenomenon predominates over micellization. A meticulous evaluation of derived parameters suggests the suitability of non-ionic surfactant (Tween 80) over ionic surfactants (CTAB and SDS) for formation of stable oil-in-water (O/W) emulsion. In solubilization study, the ultra-low IFT value (10−3 to 10−5 mN/m) between oil-middle phase emulsion with 0.5 wt% Tween 80 at varying salinity calculated by Chun-Huh equation indicates the increased solubility of oil in emulsion. Nanoemulsions prepared by high energy method using Tween 80 and n-heptane with droplet size in the range 91.05 to 40.16 nm manifest kinetic stability due to continuous Brownian motion of droplets. The dissolving capacity of crude oil in nanoemulsion was determined by miscibility test. The synergetic effect of silica nanoparticles (NPs) in presence of Tween 80 shows enhancement in stability of nanoemulsion with drop in droplets size from 36.15 to 21.37 nm and surface charge of −59.05 mV. The formulated nanoemulsions show Pseudo-plastic behavior with viscosity in the range of 9–12.5 mPa-s, which is further improved in presence of nanoparticles.
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•Formation of oil-in-water nanoemulsion with enhanced surface properties•Higher solubilization parameter with ultralow IFT implies good emulsifying capacity.•Good miscibility behavior with crude oil indicates better oil recovery.•Pseudoplastic nature with stable viscosity denotes improved mobility control.•Highly desirable properties of nanoemulsion favor its industrial applicability.
Nanoemulsion systems comprising n-heptane (oleic component), stabilized by the {gemini surfactant (14-6-14 GS) + polymer partially hydrolyzed poly-acrylamide (PHPA) + silica (SiO2) nanoparticle} ...shell and dispersed in aqueous phase, were synthesized by ultrasonication (high-energy method). Influence of ultrasonication time on nanoemulsion kinetics was investigated to predict the saturation droplet diameter. Morphological analysis by transmission electron cryomicroscopy imaging showed that oleic phase appears as uniformly dispersed spherical droplets in 14-6-14 GS-stabilized nanoemulsion, which on PHPA addition changes into a network structure consisting of larger oil droplets. 14-6-14 + PHPA + SiO2 nanoemulsion systems show more effective packing arrangement with irregular-shaped (nonspherical) droplets. Dynamic light scattering studies identified droplet size distribution profiles in the range 4.2–25.4 nm for the surfactant-stabilized nanoemulsion, 125.9–358.8 nm for the surfactant–polymer nanoemulsion, and 88.4–222.3 nm for the surfactant–polymer–nanoparticle-based nanoemulsion in optimal dosage(s). Statistical analyses were performed using normal, log-normal, and Cauchy–Lorentz distribution functions. A modified form of Hinze theory was employed to model droplet behavior in analyzed nanoemulsion systems. Zeta potential values of nanoemulsions were studied at different time intervals to determine kinetic stability as well as corroborate Hinze model findings. In summary, this article aims at investigating nanoemulsion droplet stability by thorough examination of electrostatic repulsive barrier and steric hindrance effects.
The document titled "Expert Opinion on Conduction System Pacing Implantation" provides expert insights and guidelines for the implementation of conduction system pacing (CSP). CSP offers a more ...physiologically sound alternative to conventional right ventricular pacing, and it is increasingly utilized not only for pacing but also for cardiac resynchronization therapy. In this article, we aim to encapsulate the EHRA Clinical Consensus Statement on CSP implantation, offering healthcare practitioners a standardized procedure while underscoring key recommendations
Following two reports of monkeypox virus infection in individuals who returned from Nigeria to the USA, one who returned to Texas (July 2021) and the other to the Washington, DC area (November 2021), ...the number of monkeypox infection have dramatically increased. This sounded an alarm of potential for spreading of the virus throughout the USA. During 2022, there was a report of monkeypox virus infection (May 6, 2022) in a British national following a visit to Nigeria who developed readily recognizable signs and symptoms of monkeypox virus infection. Soon following this report, case numbers climbed. By June 10, 2022, more than 1,500 cases were reported in 43 countries, including Europe and North America. While the prevalence of the monkeypox virus is well known in central and western Africa, its presence in the developed world has raised disturbing signs for worldwide spread. While infection was reported during the past half-century, starting in the Democratic Republic of Congo in 1970, in the United States, only sporadic monkeypox cases have been reported. All cases have been linked to international travel or through African animal imports. The monkeypox virus is transmitted through contact with infected skin, body fluids, or respiratory droplets. The virus spreads from oral and nasopharyngeal fluid exchanges or by intradermal injection; then rapidly replicates at the inoculation site with spreads to adjacent lymph nodes. Monkeypox disease begins with constitutional symptoms that include fever, chills, headache, muscle aches, backache, and fatigue. Phylogenetically the virus has two clades. One clade emerged from West Africa and the other in the Congo Basin of Central Africa. During the most recent outbreak, the identity of the reservoir host or the primary carriage remains unknown. African rodents are the suspected intermediate hosts. At the same time, the Centers for Disease Control (CDC) affirmed that there are no specific treatments for the 2022 monkeypox virus infection; existing antivirals shown to be effective against smallpox may slow monkeypox spread. A smallpox vaccine JYNNEOS (Imvamune or Imvanex) may also be used to prevent infection. The World Health Organization (WHO), has warned that the world could be facing a formidable infectious disease challenge in light of the current status of worldwide affairs. These affairs include the SARS-COVID-19 pandemic and the Ukraine-Russia war. In addition, the recent rise in case of numbers worldwide could continue to pose an international threat. With this in mind, strategies to mitigate the spread of monkeypox virus are warranted.
► The soil-, aggregate- and occluded C significantly influence greenhouse gas (GHG) flux from soil. ► The microaggregate C is relatively protected but the occluded C in macroaggregates is not ...stabilized. ► The mitigation potential of residue retention decreases with time and rate of addition. ► With 15 years of mulch application, the soil may be approaching its SOC sink capacity. ► Residues had dominant effect than fertilizers, in terms of aggregation and the GHG flux.
Mulching effect on carbon (C) sequestration depends on soil properties, mulch material, and the rate and duration of application. Thus, rate of soil C sequestration was assessed on a 15 year field study involving three levels of wheat straw at 0 (M0), 8 (M8) and 16 (M16) Mgha−1yr−1, at two levels (244kgNha−1yr−1, F1 and without, F0) of supplemental N. Soil C concentration was assessed in relation to aggregation and occlusion in aggregates of a silt loam Alfisol under a no-till (NT) and crop-free system in central Ohio. In comparison to control, soil organic carbon (SOC) concentration in the 0–10cm depth of bulk soil increased by 32% and 90% with M8 and M16 treatments with a corresponding increase in the SOC stock by 21–25% and 50–60%, respectively. With increase in rate of residue mulch, proportion of water stable aggregates (small macroaggregates, >250μm size) increased by 1.4–1.8 times and of microaggregates (53–250μm) by 1.4 times. Fertilizer N significantly increased the SOC concentration of small macroaggregates under M16 treatments only. Ultra-sonication showed that 12–20% of SOC occluded in the inter-microaggregate space of small macroaggergates, was a function of both mulch and fertilizer rates. Significantly higher and positive correlation of greenhouse gases (GHGs), CO2, CH4 and N2O flux was observed with C and N concentrations of small macroaggregates and also of the occluded fraction of small macroaggregates. The higher correlation coefficient indicated the latter to be prone to microbial attack. On the contrary, non-significant relationship with C and N concentrations of microaggregates indicate a possible protection of microaggregate C. The diurnal fluxes of CO2, CH4 and N2O were the lowest under bare soil and the highest under high mulch rate with added N, with values ranging from 1.51 to 2.31gm−2d−1, −2.79 to 3.15mgm−2d−1 and 0.46 to 1.02mgm−2d−1, respectively. Mulch rate affected the GHGs flux more than did the fertilizer rates. The net global warming potential (GWP) was higher for high mulch (M16) than low mulch (M8) rates, with values ranging from 0.46 to 0.57 Mg CO2 equivalent – Cha−1yr−1 (M8) and 1.98 to 3.05Mg CO2 equivalent – Cha−1yr−1 (M16). In general, mulch rate determined the effect of fertilizers. The study indicated that over long-term, a mulch rate between 8 and 16Mgha−1yr−1 may be optimal for Alfisols in Central Ohio.
•Several conflicting performance measures are to be satisfied in controller design problems.•ITAE, minimum damping ratio and settling times are used as objectives functions.•NSGA-II is applied to ...generate Pareto set of PI/PID controller parameters.•Best compromise solution is selected by a Fuzzy based approach.•Linear and nonlinear models are considered and results are compared with GA, BFOA and CPSO.
Controllers design problems are multi objective optimization problems as the controller must satisfy several performance measures that are often conflicting and competing with each other. In multi-objective approach a set of solutions can be generated from which the designer can select a final solution according to his requirement and need. This paper presents the design and analysis Proportional Integral (PI) and Proportional Integral Derivative (PID) controller employing multi-objective Non-Dominated Shorting Genetic Algorithm-II (NSGA-II) technique for Automatic Generation Control (AGC) of an interconnected system. To minimize the effect of noise in the input signal, a filter is employed with the derivative term. Integral Time multiply Absolute Error (ITAE), minimum damping ratio of dominant eigenvalues and settling times in frequency and tie-line power deviations are considered as multiple objectives and NSGA-II is employed to generate Pareto optimal set. Further, a fuzzy-based membership value assignment method is employed to choose the best compromise solution from the obtained Pareto solution set. The proposed approach is first applied to a linear two-area power system model and then extended to a non-linear power system model by considering the effect of governor dead band non-linearity. The superiority of the proposed NSGA-II optimized PI/PID controllers has been shown by comparing the results with some recently published modern heuristic optimization approaches such as Bacteria Foraging Optimization Algorithm (BFOA), Genetic Algorithm (GA) and Craziness based Particle Swarm Optimization (CPSO) based controllers for the similar interconnected power systems.
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