UNDERSTANDING STRUCTURE-PROPERTY RELATIONSHIPS AT THE NANO-BIO INTERFACE FOR DELIVERY APPLICATIONS

The surface chemistry of the nanomaterials creates an effective interface between two entirely different worlds: nanotechnology and biology. Understanding the interaction between nanomaterial surface chemistry and biological entities can be useful for a wide variety of biomedical applications as well as can provide crucial information for nanotoxicology. In my research, I have used gold nanoparticles as a model platform to synthesize a family of nanoparticles with atomic level control of their surface properties and probe their interaction with biological systems. First part of my research focused on the understanding the uptake mechanisms, toxicity, and hemolytic properties of cationic nanoparticles, an excellent gene delivery vectors, and provide design parameters to avoid toxic consequences. In the second part of my research, a new class of surface engineered antifouling nanomaterials were fabricated that can eschew plasma protein binding, providing opportunity to interrogate nano-biological behavior without any complications arising from the protein binding to nanomaterial surface. Since the surface chemistry of nanoparticles dictates the interaction between nanomaterials and biological entities, the findings in this thesis can be generalized to nanomaterials with a wide of variety of core materials of unique physical properties

Turbine Blade Internal Cooling: Trailing Edge, Coolant-Passage Entry, Bend Effect and Improvement in Thermal Performance

Efficient cooling of gas turbine blade is imperative for safe operation of the gas turbine engine at high temperatures. In the present work, two converging lattice structures suitable for trailing edge applications are tested and their performance is compared with a conventional pin-fin configuration. Another constant cross section lattice structure is tested to see the cooling efficiency of lattice channels with different number of sub-channels. Converging lattice structures show higher heat transfer enhancement and comparable or higher thermal performance than traditional pin-fin cooling used in gas turbine trailing edge. The highest pressure drop incurred in a multi-pass channel is at the bend region. A turbine designer always desires to reduce the pressure drop in the bend region without reducing the heat transfer in that region. A total of nine different bend geometries are studied numerically and their performance is compared with a baseline U-bend geometry. Modifications for the bend geometry are made along the channel divider wall and at the endwall of the 180 degree bend. From the numerical study, two geometries (symmetrical bulb and bulb-bow combination) are down selected for experimental study with the goal of improving the Thermal Performance Factor (TPF) in the coolant channel. Different shapes and arrangements of rib turbulators were studied over the last few decades to enhance local turbulence close to the hot gas turbine blade wall and promote secondary flow close to the wall. A combination of angled grooves and angled ribs are used to find the heat transfer and pressure drop across the channel and compare their performance with standard ribbed channel. A 1:4 Aspect Ratio (AR) two-pass cooling channel is tested with three different entrance geometries under stationary conditions. It is seen that the presence of the complex entrance geometries changes the heat transfer enhancement profile at the inlet of the test section significantly when compared to a fully developed entrance. Numerical simulations are done in rotating condition to see the complex interaction of the entrance geometry driven flow and rotation induced flow

Systematization of a 256-bit lightweight block cipher Marvin

In a world heavily loaded by information, there is a great need for keeping specific information secure from adversaries. The rapid growth in the research field of lightweight cryptography can be seen from the list of the number of lightweight stream as well as block ciphers that has been proposed in the recent years. This paper focuses only on the subject of lightweight block ciphers. In this paper, we have proposed a new 256 bit lightweight block cipher named as Marvin, that belongs to the family of Extended LS designs.Comment: 12 pages,6 figure

SENAS: Security driven ENergy Aware Scheduler for Real Time Approximate Computing Tasks on Multi-Processor Systems

Present day real time approximate computing applications like image and video processing involves execution of a set of tasks before a certain amount of time or deadline. In addition to this, present day systems are associated with strict energy budget that cannot be changed post deployment. The tasks comprises of a mandatory and optional part. Completion of all mandatory portions of all tasks before deadline is much more important than result accuracy in such real time approximate computing applications. Based on the energy budget, the optional portions can be executed that determines the quality of service (QoS) of the system. In ideal scenario, sufficient energy budget is present that ensures completion of both mandatory and optional portions in a system with a pre-determined number of processors. However, if fault or malware attack occurs on one or more processors, then the system will cease to work and results may be fatal. In this work, we consider such a scenario where the processors may be faulty and stop functioning in post deployment phases or some malware may cause unexpected delays in processing or may cause unexpected power draining at runtime that will prevent the system from meeting its deadline. We propose a Security driven ENergy Aware Scheduler (SENAS) that works as a self aware agent. Initially, based on the available energy budget, SENAS determines which task is to be executed in which processor of a system. At runtime, SENAS constantly monitors the working of the processors and on detecting any anomaly in any of the processors, it reschedules its tasks at runtime by reducing execution of the optional portions of the tasks and ensuring completion before deadline with high QoS

Pro-Oxidant Therapeutic Activities of Cerium Oxide Nanoparticles in Colorectal Carcinoma Cells

Given that basal levels of reactive oxygen species (ROS) are higher in cancer cells, there is a growing school of thought that endorses pro-oxidants as potential chemotherapeutic agents. Intriguingly, cerium oxide (CeO2) nanoparticles can manifest either anti- or pro-oxidant activity as a function of differential pH of various subcellular localizations. In an acidic pH environment, for example, in extracellular milieu of cancer cells, CeO2 would function as a pro-oxidant. Based on this concept, the present study is designed to investigate the pro-oxidant activities of CeO2 in human colorectal carcinoma cell line (HCT 116). For comparison, we have also studied the effect of ceria nanoparticles on human embryonic kidney (HEK 293) cells. Dose-dependent viability of cancerous as well as normal cells has been assessed by treating them independently with CeO2 nanoparticles of different concentrations (5-100 mu g/mL) in the culture media. The half maximal inhibitory concentration (IC50) of nanoceria for HCT 116 is found to be 50.48 mu g/mL while that for the HEK 293 cell line is 92.03 mu g/mL. To understand the intricate molecular mechanisms of CeO2-induced cellular apoptosis, a series of experiments have been conducted. The apoptosis-inducing ability of nanoceria has been investigated by Annexin V-FITC staining, caspase 3/9 analysis, cytochrome c release, intracellular ROS analysis, and mitochondrial membrane potential analysis using flow cytometry. Experimental data suggest that CeO2 treatment causes DNA fragmentation through enhanced generation of ROS, which ultimately leads to cellular apoptosis through the p53-dependent mitochondrial signaling pathway

Adoption of circular economy practices in small and medium-sized enterprises: Evidence from Europe and the UK

Circular Economy (CE) practices have the potential to enhance sustainability performance of organisations and thus help respond to United Nations Sustainability Development Goals. The aim of this research is to examine the adoption of CE in small and medium sized enterprises (SMEs) and its impact on sustainability performance. We analyze the current state of CE practices and its impact on sustainability performance across key CE fields of action (design, procurement, production, distribution, consumption and recover) of SMEs in France, Greece, Spain and the UK A mixed-methods approach (survey, interviews, case studies) is adopted to collect data from around 100 SMEs in each country, employing resource-based view as the theoretical lens. Our findings reveal that CE adoption can result into superior environmental performance compared to economic and social performance. Moreover, the ‘design’ function contributes the most towards the adoption of CE in SMEs, whereas the ‘recover’ function contributes the least, considering the current state-of-practices. From a theoretical perspective, we outline the issues and challenges, impact of support from customers and policymakers, and self-motivation of SMEs to adopt CE. Based on the findings, we propose an implementation framework for SMEs to develop organisation wide strategic initiatives for CE adoption in business operations

Constraints on the cosmic expansion history from GWTC-3

We use 47 gravitational-wave sources from the Third LIGO-Virgo-KAGRA Gravitational-Wave Transient Catalog (GWTC-3) to estimate the Hubble parameter $H(z)$, including its current value, the Hubble constant $H_0$. Each gravitational-wave (GW) signal provides the luminosity distance to the source and we estimate the corresponding redshift using two methods: the redshifted masses and a galaxy catalog. Using the binary black hole (BBH) redshifted masses, we simultaneously infer the source mass distribution and $H(z)$. The source mass distribution displays a peak around $34\, {\rm M_\odot}$, followed by a drop-off. Assuming this mass scale does not evolve with redshift results in a $H(z)$ measurement, yielding $H_0=68^{+12}_{-7} {\rm km\,s^{-1}\,Mpc^{-1}}$ ($68\%$ credible interval) when combined with the $H_0$ measurement from GW170817 and its electromagnetic counterpart. This represents an improvement of 17% with respect to the $H_0$ estimate from GWTC-1. The second method associates each GW event with its probable host galaxy in the catalog GLADE+, statistically marginalizing over the redshifts of each event's potential hosts. Assuming a fixed BBH population, we estimate a value of $H_0=68^{+8}_{-6} {\rm km\,s^{-1}\,Mpc^{-1}}$ with the galaxy catalog method, an improvement of 42% with respect to our GWTC-1 result and 20% with respect to recent $H_0$ studies using GWTC-2 events. However, we show that this result is strongly impacted by assumptions about the BBH source mass distribution; the only event which is not strongly impacted by such assumptions (and is thus informative about $H_0$) is the well-localized event GW190814

Open data from the third observing run of LIGO, Virgo, KAGRA and GEO

The global network of gravitational-wave observatories now includes five detectors, namely LIGO Hanford, LIGO Livingston, Virgo, KAGRA, and GEO 600. These detectors collected data during their third observing run, O3, composed of three phases: O3a starting in April of 2019 and lasting six months, O3b starting in November of 2019 and lasting five months, and O3GK starting in April of 2020 and lasting 2 weeks. In this paper we describe these data and various other science products that can be freely accessed through the Gravitational Wave Open Science Center at https://gwosc.org. The main dataset, consisting of the gravitational-wave strain time series that contains the astrophysical signals, is released together with supporting data useful for their analysis and documentation, tutorials, as well as analysis software packages.Comment: 27 pages, 3 figure

Search for continuous gravitational wave emission from the Milky Way center in O3 LIGO--Virgo data

We present a directed search for continuous gravitational wave (CW) signals emitted by spinning neutron stars located in the inner parsecs of the Galactic Center (GC). Compelling evidence for the presence of a numerous population of neutron stars has been reported in the literature, turning this region into a very interesting place to look for CWs. In this search, data from the full O3 LIGO--Virgo run in the detector frequency band $[10,2000]\rm~Hz$ have been used. No significant detection was found and 95$\%$ confidence level upper limits on the signal strain amplitude were computed, over the full search band, with the deepest limit of about $7.6\times 10^{-26}$ at $\simeq 142\rm~Hz$. These results are significantly more constraining than those reported in previous searches. We use these limits to put constraints on the fiducial neutron star ellipticity and r-mode amplitude. These limits can be also translated into constraints in the black hole mass -- boson mass plane for a hypothetical population of boson clouds around spinning black holes located in the GC.Comment: 25 pages, 5 figure