Search

Shirisha Bellala,1,* Karthika Viswanathan,2,* Ujwala Guntakanti,3 Anitha Kowthalam,1 Sung Soo Han,4 Madhusudana Rao Kummara,4 Sreekanth Reddy Obireddy,1,5 Wing-Fu Lai5– 7 1Department of Chemistry, Sri Krishnadevaraya University, Anantapur, Andhra Pradesh, 515003, India; 2Department of Nanoscience and Technology, Alagappa University, Karaikudi, Tamil Nadu, 630 003, India; 3Department of Chemistry, G. Pulla Reddy Engineering College, Kurnool, Andhra Pradesh, 518 007, India; 4School of Chemical Engineering, Yeungnam University, Gyeongsan, 38541, Republic of Korea; 5Department of Urology, Zhejiang Provincial People’s Hospital, Affiliated People’s Hospital, Hangzhou Medical College, Zhejiang, 310014, China; 6School of Food Science and Nutrition, University of Leeds, Leeds, LS2 9JT, UK; 7Department of Applied Biology and Chemical Technology, Hong Kong Polytechnic University, Hong Kong Special Administrative Region, China*These authors contributed equally to this workCorrespondence: Wing-Fu Lai, Email rori0610@graduate.hku.hk; Sreekanth Reddy Obireddy, Email sreekanthchem7@gmail.comPurpose: The purpose of this study is to address the need for efficient drug delivery with high drug encapsulation efficiency and sustained drug release. We aim to create nanoparticle-loaded microgels for potential applications in treatment development.Methods: We adopted the process of ionic gelation to generate microgels from sodium alginate and carboxymethyl cellulose. These microgels were loaded with doxorubicin-conjugated amine-functionalized zinc ferrite nanoparticles (AZnFe-NPs). The systems were characterized using various techniques. Toxicity was evaluated in MCF-7 cells. In vitro release studies were conducted at different pH levels at 37 oC, with the drug release kinetics being analyzed using various models.Results: The drug encapsulation efficiency of the created carriers was as high as 70%. The nanoparticle-loaded microgels exhibited pH-responsive behavior and sustained drug release. Drug release from them was mediated via a non-Fickian type of diffusion.Conclusion: Given their high drug encapsulation efficiency, sustained drug release and pH-responsiveness, our nanoparticle-loaded microgels show promise as smart carriers for future treatment applications. Further development and research can significantly benefit the field of drug delivery and treatment development.Keywords: sodium alginate, carboxymethyl cellulose, doxorubicin, zinc ferrite nanoparticles, microgels

It is a distinct privilege to produce this article to honor Professor Tam, the foremost authority on jet aeroacoustics. The fundamental characteristics of jet noise have been studied for 70 years, since the pioneering work of Lighthill in the 1950s. The acoustic analogy, with many variants, has served as the leading theory for nearly 50 years. Many leading researchers in the 1970s formulated theories to interpret the measured trends from subsonic and supersonic jets, using acoustic analogy and flow features as the framework. Quadrupoles, dipoles and monopoles were believed to constitute the sources of noise. The discovery of large-scale organized structures in free shear layers and jets sparked a different avenue of thinking about their importance for noise generation. Tam was the first to clearly demonstrate that these structures are efficient generators of noise and constitute the dominant noise sources, especially in the downstream direction. Now, two schools of thought emerged on the sources of jet noise. Experimental measurements showed that the mean flow as well as the turbulence statistics exhibit a self-similarity in the mixing layer and another similarity in the fully developed jet. Based on these observations, Tam proposed that since noise is generated by the turbulence of the jet, the noise spectra generated by fine-scale and large-scale turbulence should also exhibit self-similarity. By examining a large set of supersonic jet noise data acquired at NASA Langley, Tam offered evidence that the turbulent mixing noise of high-speed jets does consist of two independent self-similar components. In this paper, experimental evidence is compiled from an extensive database that quantifies the effect of several parameters that affect jet spectra. A new scaling method is developed and extended to noise predictions for realistic dual-stream nozzle geometries. The objectives of this paper are to serve as a synthesis of noise characteristics and to focus on application to real-world problems. Results from five different experimental measurements are examined: (1) farfield spectral characteristics; (2) azimuthal and polar correlations in the farfield; (3) correlations of jet turbulence fluctuations and farfield sound; (4) measurement of source distributions with an elliptic mirror; and (5) space-time correlation measurements in the nearfield with a cage array, and nearfield-farfield correlations. Two distinctly different trends are observed in the angular ranges of 50° – ∼120° and ∼120° – 165° for all the parameters investigated with the above five approaches. The salient observations are mutually supporting, and the cumulative weight lends credence to the proposition that there are two distinct sources of turbulent mixing noise. [ABSTRACT FROM AUTHOR]

This introduction provides a brief personal background and highlights the scientific accomplishments of Professor Christopher Tam. He has maintained extremely high standards of research and an enviable track record for productivity, spanning more than five decades. The depth and breadth of his technical output are truly breathtaking, and he has inspired scores of researchers and graduate students. When the first author was an Acoustics Engineer at Lockheed, Georgia, he started collaborating with Chris in the early 1990s. There were several joint projects when the author moved to Boeing, which encompassed both fundamental research and applications. The second author has an even longer association with Chris, initially as a PhD advisee in the late 1980s and then as a co-researcher. In this special volume we pay tribute to Chris's many achievements, an endeavor that provides us with great satisfaction and which is long overdue. [ABSTRACT FROM AUTHOR]

This paper addresses the issue of effective content-delivery of Computer Science subjects taking advantage of a university intranet. The proposal described herein for teaching a subject like Combinatorics and Graph Theory (CGT) is to supplement lectures with a moderated online forum against an associated intranet portal, which is referred to as a CGT-portal. The contents of a CGT-portal in a university intranet is required to be assembled by moderators and students during the progress of the CGT course. When completed at the end of a CGT course, a CGT-portal may be seen as a restricted view of the "Online Encyclopaedia of Integer Sequences" (OEIS: see http://oeis.org--the restriction can be with respect to sequences in OEIS that are directly relevant to say CGT). In the context of OEIS, an integer-sequence enthusiast experiences this cycle: "understand a page in OEIS--ponder over the contents--read afresh/refresh related content--suggest new additions to OEIS--wait for approval or rejection"--repeat this cycle. This experience can be imparted to students of a CGT course with the help of a CGT-portal. For organizing a CGT course, a first task is to partially create a miniature OEIS-like instructor-moderated CGT-portal in a university intranet. During the course of lectures and tutorials in CGT, students are asked to explore/contribute to the CGT-portal and these may be critically augmented/approved by instructors suitably, to find a place in the portal. Moderation also includes "feedbacks" (in many sense, a form of guidance) to students using/contributing to, the portal. By this, many concepts can be conveyed to the students in an interesting way with the desired results. It is pointed out that the dynamic nature of a CGT-portal promotes "active learning" philosophy, the success of which depends on understanding the background and psychology of the student population. Some design guidelines associated with the building-up of a CGT-portal e.g., grouping of prerequisites of a logical page, knowledge-representation related observations, useful interfaces to the portal are also presented.

Non-axisymmetric geometries, mainly elliptic and rectangular, have been proposed for the reduction of jet noise vis-à-vis round nozzles. Most of the studies of these nozzles are from unheated jets and are restricted to nozzles of very small size. Furthermore, all of them have been carried out at static conditions, thereby rendering their value to insignificance for practical applications. All engines in service with long ducts and a confluent nozzle incorporate an internal lobed mixer. The aeroacoustic characteristics of an elliptic compound nozzle that represents the geometry of an existing low bypass ratio (BPR) turbofan engine, is investigated at 1/7th scale in this study. Typical engine cycle conditions are chosen; data are acquired statically and in the presence of a flight stream. The aspect ratio of the nozzle is 2.0; higher aspect ratios are not suitable for engine applications. The results are compared with a round compound nozzle with the same internal geometry, so as to assess the acoustic benefit, if any, of the elliptic nozzle. Both a simple internal splitter and an in-service lobed mixer have been considered. The elliptic nozzle introduces azimuthal asymmetry even for an unheated jet; the magnitude of azimuthal variation becomes pronounced for heated jets. Typically, the lowest level of noise is observed towards the narrow side of the elliptic nozzle (ϕ = 0°); the noise level gradually increases and reaches a maximum towards the broader side (ϕ = 90°). Though there are some superficial similarities between the elliptic and beveled nozzles, it is shown that the noise characteristics are very different. A systematic study is carried out, with step-by-step build up to realistic geometry, with forward flight. A large noise reduction of ∼3 to ∼4 EPNdB is observed for the splitter nozzle under static conditions. The introduction of a realistic lobed mixer reduces this benefit to close to zero. Finally, there is a noise increase at all azimuthal angles with forward flight. Therefore, the elliptic nozzle does not provide any EPNL benefit for actual nozzle geometry and consequently does not constitute a viable design for noise reduction. The importance of evaluating noise reduction concepts using appropriate geometry and under realistic forward flight conditions is emphasized once again. [ABSTRACT FROM AUTHOR]

In this work, anomalous solute transport using adsorption effects and the decomposition of solute was studied. During the filtration of inhomogeneous liquids, a number of new phenomena arise, and this is very important for understanding the mechanisms of the filtration process. Recently, issues of mathematical modeling of substance transfer processes have been intensively discussed. Modeling approaches are based on the law of matter balance in a certain control volume using additional phenomenological relationships. The process of anomalous solute transport in a porous medium was modeled by differential equations with a fractional derivative. A new mobile—immobile model is proposed to describe anomalous solute transport with a scale-dependent dispersion in inhomogeneous porous media. The profiles of changes in the concentrations of suspended particles in the macropore and micropore were determined. The influence of the order of the derivative with respect to the coordinate and time, i.e., the fractal dimension of the medium, was estimated based on the characteristics of the solute transport in both zones. The hydrodynamic dispersion was set through various relations: constant, linear, and exponential. Based on the numerical results, the concentration fields were determined for different values of the initial data and different relations of hydrodynamic dispersion. [ABSTRACT FROM AUTHOR]

This mathematical model studies the dynamics of tumor growth, one of the most complex dynamics problems that relates several interrelated processes over multiple ranges of spatial and temporal scales. In order to construct a tumor growth model, an angiogenesis model is used with focus on controlling the tumor volume, preventing new establishment, dissemination, and growth. The lattice Boltzmann method (LBM) is effectively applied to Navier-Stokes' equation for obtaining the numerical simulation of blood flow through vasculature. It is observed that the flow features are extremely sensitive to stenosis severity, even at small strains and stresses, and that a severe effect on flow patterns and wall shear stresses is noticed in the tumor blood vessels. It is noted that based on the nonlinear deformation of the blood vessel's wall, the flow rate conditions became unstable or distorted and affect the complex blood vessel's geometry and it changes the blood flow pattern. When the blood flows inside the stenotic artery, depending on the presence of moderate or severe stenosis, it can lead to insufficient blood supply to the tissues in the downstream. Consequently, the highly disturbed flow occurs in the downstream of the stenosed artery, or even plaque ruptures happen when the flow pattern becomes very irregular and complex as it transits to turbulent which cannot be described without assumptions on the geometry. The results predicted by LBM-based code surpassed the expectations, and thus, the numerical results are found to be in great accord with the relevant established results of others. [ABSTRACT FROM AUTHOR]