Search Results (14)

Green-synthesis routes for producing CuO nanoparticles offer a simplified, sustainable, and low-cost replacement for conventional chemical methods, eliminating the need for harsh chemicals and providing an easily scalable process for industrial-level production. Although numerous studies have investigated synthesizing CuO nanoparticles from single plant extracts, comparative assessments of multi-plant-mediated CuO nanoparticles alongside synthetic CuO remain limited. In this work, CuO nanoparticles were green-synthesized from three different plant sources, namely ginger, red onion peels, and garlic, and their physicochemical and biological properties were tested against the synthetic CuO. All plant extracts produced pure-phased monoclinic CuO nanoparticles as confirmed by UV–Vis, XRD, FTIR, and SEM/EDX analyses. SEM showed distinct nanoparticle morphologies, with CuO from ginger extract exhibiting uniform nanocubes, while nanoparticles from red onion and garlic extracts exhibited more aggregated and irregular structures. Their crystallite sizes were 8–9 nm lower than the ~11 nm observed for the synthetic CuO, highlighting the phytochemical role in shaping the nanoparticles’ morphology. The antibacterial efficacy against S. aureus and E. coli showed that ginger-derived and synthetic CuO had the strongest bacterial inhibition and bactericidal potency compared to onion- and garlic-derived CuO samples. However, synthetic CuO had the highest cytotoxicity risk, hindering its suitability for biological uses, while CuO-ginger maintained good cell viability at moderate concentrations. CuO-onion and CuO-garlic gave lower antibacterial cytocompatibility performance due to their thicker capping layers, which led to decreased Cu²⁺ release and ROS production. Ginger-derived CuO achieved an optimal trade-off between antibacterial and cytotoxic efficiency, highlighting its prospects as a candidate for biomedical applications. Full article

Western flower thrips (WFT; Frankliniella occidentalis (Pergande)) is a major pest of greenhouse ornamental crops in Ontario, Canada, and recent surveys indicate onion thrips (OT; Thrips tabaci Lindeman) is becoming increasingly prevalent. This study investigates primary routes of entry for WFT and OT in the Niagara region of Ontario. Imported plant material (chrysanthemum cuttings) was sampled from 2016 to 2019 to confirm thrips presence and species identity. Entry from outside was evaluated from June to November in 2019 at three commercial greenhouses that produced chrysanthemums year-round with a mix of vegetative, budding, and flowering plants present. Sticky cards were mounted inside and outside from June to November, and plant taps were conducted bi-weekly to evaluate thrips establishment in the crop. Cuttings consistently harboured thrips, averaging 0.04 thrips per cutting. In 2019, all but one adult specimen collected on cuttings were WFT, confirming this is an important route of entry for WFT. Onion thrips were not found on cuttings but was prevalent on cards both outside and inside greenhouses. More OT was caught on outside cards and a significant correlation between inside and outside cards (Efron’s pseudo-R² = 0.64) indicates outside populations are a likely source of OT. Additionally, eastern flower thrips (EFT; Frankliniella tritici Fitch) was abundant on cards, but uncommon in the crop. Indoor cards were poor indicators of species composition within the crop, significantly underrepresenting WFT by 71% and overrepresenting EFT by 246%, compared to plant taps. These findings support the use of cutting dips for imported cuttings, in addition to physical control measures to reduce infestation from outdoor populations. This study also highlights the importance of plant inspections for gathering accurate data when making pest management decisions as sticky cards alone may not reliably reflect thrips populations. Full article

Real-time peer-to-peer communication in web browsers typically relies on centralized signaling servers, creating single points of failure, privacy vulnerabilities, and censorship risks. We present WebRTC Swarms, a fully decentralized signaling architecture integrated into GRIDNET OS that combines onion-routed relay circuits with designated verifier zero-knowledge authentication and cryptoeconomic incentives. The proposed system empowers peers to discover and connect without exposing identities or IP addresses through an overlay of incentivized full nodes that carry signaling traffic using transmission tokens. We introduce a MAC-based designated verifier ZK authentication protocol allowing peers sharing a pre-shared key to mutually authenticate without revealing the key, ensuring only authorized participants can join sessions while preserving unlinkability to outsiders across sessions. Through formal verification using TLA+, we prove key safety and liveness properties of both the signaling protocol and the authentication mechanism. Empirical evaluation demonstrates near-100% NAT traversal success via incentivized decentralized TURN relaying (compared to approximately 85% for STUN-only approaches), join latencies under 2 s for swarms of dozens of peers, and strong resilience against Sybil and denial-of-service attacks through token-based rate limiting. Our work represents the first practical integration of decentralized WebRTC signaling with designated verifier cryptographic authentication and built-in economic incentives, providing a privacy-first substrate for secure, community-governed communication networks. Full article

Graphitic nanomaterials have emerged as foundational components in nanoscience owing to their exceptional electrical, mechanical, and chemical properties, which can be tuned by controlling dimensionality and structural order. From zero-dimensional (0D) quantum dots, carbon nano-onions, and nanodiamonds to one-dimensional (1D) nanoribbons, two-dimensional (2D) nanowalls, and three-dimensional (3D) graphene foams, these architectures underpin advancements in catalysis, energy storage, sensing, and electronic technologies. Among various synthesis routes, chemical vapor deposition (CVD) provides unmatched versatility, enabling atomic-level control over carbon supply, substrate interactions, and plasma activation to produce well defined graphitic structures directly on functional supports. This review presents a comprehensive, dimension-resolved overview of CVD-derived graphitic nanomaterials, examining how process parameters such as precursor chemistry, temperature, hydrogen etching, and template design govern nucleation, crystallinity, and morphological evolution across 0D to 3D hierarchies. Comparative analyses of Raman, XPS, and XRD data are integrated to relate structural features with growth mechanisms and functional performance. By connecting mechanistic principles across dimensional scales, this review establishes a unified framework for understanding and optimizing CVD synthesis of graphitic nanostructures. It concludes by outlining a path forward for improving how CVD-grown carbon nanomaterials are made, monitored, and integrated into real devices so these can move from lab-scale experiments to practical, scalable technologies. Full article

Across a diverse landscape of anonymity designs, the dominant paradigms—onion routing (e.g., Tor) and mix networks (e.g., Loopix)—carry intrinsic constraints: long-lived circuits invite traffic correlation, and mixnets often rely on a network-wide state, making it hard to reconcile anonymity and scalability. This paper presents Draughts, a fully decentralized system in which each packet follows an independent and dynamically determined transmission path. Built upon Jump routing, Draughts introduces three key innovations: (i) replacing global state $O\left(N\right)$ with local two-hop neighborhood knowledge $O\left(k^2\right)$; (ii) supporting anonymous replies to enable real-time bidirectional communication; and (iii) proposing a path-length control mechanism that balances anonymity and transmission efficiency. Evaluation results show that Draughts achieves strong sender anonymity, resists predecessor and traffic analysis attacks, and reduces receiver buffer maintenance overhead, achieving a favorable trade-off between anonymity and performance. Full article

The efficiency of Shor’s and Grover’s algorithms and the advancement of quantum computers implies that the cryptography used until now to protect one’s privacy is potentially vulnerable to retrospective decryption, also known as the harvest now, decrypt later attack in the near future. This dissertation proposes an overview of the cryptographic schemes used by Tor, highlighting the non-quantum-resistant ones and introducing theoretical performance assessment methods of a local Tor network. The measurement is divided into three phases. We start with benchmarking a local Tor network simulation on constrained devices to isolate the time taken by classical cryptography processes. Secondly, the analysis incorporates existing benchmarks of quantum-secure algorithms and compares these performances on the devices. Lastly, the estimation of overhead is calculated by replacing the measured times of traditional cryptography with the times recorded for Post-Quantum Cryptography (PQC) execution within the specified Tor environment. By focusing on the replaceable cryptographic components, using theoretical estimations, and leveraging existing benchmarks, valuable insights into the potential impact of PQC can be obtained without needing to implement it fully. Full article

The Onion Router (Tor), as the most widely used anonymous network, is vulnerable to traffic correlation attacks by powerful passive adversaries, such as Autonomous Systems (AS). AS-level adversaries increase their chances of executing correlation attacks by manipulating the underlying routing, thereby compromising anonymity. Furthermore, these underlying routing detours in the Tor client’s routing inference introduce extra latency. To address this challenge, we propose Toward Resisting AS-level Adversary Correlation Attacks Optimal Anonymous Routing (TOAR). TOAR is a two-stage routing mechanism based on Bayesian optimization within Software Defined Networks (SDN), comprising route search and route forwarding. Specifically, it searches for routes that conform to established policies, avoiding AS that could connect traffic between clients and destinations while maintaining anonymity in the selection of routes that minimize communication costs. To evaluate the anonymity of TOAR, as well as the effectiveness of route searching and the performance of route forwarding, we conduct a detailed analysis and extensive experiments. The analysis and experimental results show that the probability of routing being compromised by correlation attacks is significantly reduced. Compared to classical enumeration-based methods, the success rate of route searching increased by close to 2.5 times, and the forwarding throughput reached 70% of that of the packet transmission. The results show that TOAR effectively improves anonymity while maintaining communication quality, minimizing anonymity loss from AS-level adversaries and reducing high latency from routing detours. Full article

The consumption of fresh produce is increasing due to its role in promoting a healthy and balanced diet. However, this trend is accompanied by increased foodborne disease cases associated with pathogens such as Escherichia, Listeria, and Salmonella. Previous studies provided evidence that the internalization of foodborne pathogens in fresh produce may be a potential contamination route and may pose a public health risk. This study investigates the combination effects of storage temperature and humidity on Salmonella internalization in six types of leafy greens (iceberg lettuce, romaine lettuce, red lettuce, green onion, spinach, and kale) during the storage stage. The results indicated that temperature plays a critical role in Salmonella internalization, with higher concentrations observed in samples stored at 25 °C compared to those stored at 7 °C. The mean concentration of internalized Salmonella in the iceberg lettuce sample was the highest and that in the green onion sample was the lowest (iceberg lettuce > red lettuce > romaine lettuce > spinach > kale > green onion). Mist conditions also had an impact on internalization. The group treated with mist showed an increase in Salmonella internalization of about 10–30% rather than the group without mist treatment. This research emphasizes the importance of understanding the factors influencing bacterial internalization in fresh produce and highlights the need for proper storage conditions to minimize the risk of contamination and ensure food safety. Full article

Li-ion capacitors (LIC) have emerged as a promising hybrid energy storage system in response to increasing energy demands. However, to achieve excellent LIC performance at high rates, along with cycling stability, an alternative anode to graphite is needed. Porous high-surface-area carbons, such as onion-like carbons (OLCs), have been recently found to hold high potential as high-rate-capable LIC anodes. However, a systematic understanding of their synthesis route and morphology is lacking. In this study, OLCs prepared from self-made metal organic frameworks (MOFs) Fe-BTC and Fe-MIL100 by a simple pyrolysis method were compared to OLCs obtained via high-temperature annealing of nanodiamonds. The LICs with OLCs produced from Fe-BTC achieved a maximum energy density of 243 Wh kg⁻¹ and a power density of 20,149 W kg⁻¹. Furthermore, excellent capacitance retention of 78% after 10,000 cycles was demonstrated. LICs with MOF-derived OLCs surpassed the energy and power density of LICs with nanodiamond-derived OLCs. We determined the impact of the MOF precursor structure and morphology on the resulting OLC properties, as well as on the electrochemical performance. Thus, MOF-derived OLCs offer significant potential toward high-performance anode material for LICs, enabling control over structure and morphology, as well as easy scalability for industrial implementation. Full article

Currently, the computational power present in the sensors forming a wireless sensor network (WSN) allows for implementing most of the data processing and analysis directly on the sensors in a decentralized way. This shift in paradigm introduces a shift in the privacy and security problems that need to be addressed. While a decentralized implementation avoids the single point of failure problem that typically applies to centralized approaches, it is subject to other threats, such as external monitoring, and new challenges, such as the complexity of providing decentralized implementations for data mining algorithms. In this paper, we present a solution for privacy-aware distributed data mining on wireless sensor networks. Our solution uses a permissioned blockchain to avoid a single point of failure in the system. Contracts are used to construct an onion-like structure encompassing the Hoeffding trees and a route. The onion-routed query conceals the network identity of the sensors from external adversaries, and obfuscates the actual computation to hide it from internally compromised nodes. We validate our solution on a use case related to an air quality-monitoring sensor network. We compare the quality of our model against traditional models to support the feasibility and viability of the solution. Full article

In the past two decades, technological advancements in smart devices, IoT, and smart sensors have paved the way towards numerous implementations of indoor location systems. Indoor location has many important applications in numerous fields, including structural engineering, behavioral studies, health monitoring, etc. However, with the recent COVID-19 pandemic, indoor location systems have gained considerable attention for detecting violations in physical distancing requirements and monitoring restrictions on occupant capacity. However, existing systems that rely on wearable devices, cameras, or sound signal analysis are intrusive and often violate privacy. In this research, we propose a new framework for indoor location. We present an innovative, non-intrusive implementation of indoor location based on wireless sensor networks. Further, we introduce a new protocol for querying and performing computations in wireless sensor networks (WSNs) that preserves sensor network anonymity and obfuscates computation by using onion routing. We also consider the single point of failure (SPOF) of sink nodes in WSNs and substitute them with a blockchain-based application through smart contracts. Our set of smart contracts is able to build the onion data structure and store the results of computation. Finally, a role-based access control contract is used to secure access to the system. Full article

Indoor Air Quality monitoring is a major asset to improving quality of life and building management. Today, the evolution of embedded technologies allows the implementation of such monitoring on the edge of the network. However, several concerns need to be addressed related to data security and privacy, routing and sink placement optimization, protection from external monitoring, and distributed data mining. In this paper, we describe an integrated framework that features distributed storage, blockchain-based Role-based Access Control, onion routing, routing and sink placement optimization, and distributed data mining to answer these concerns. We describe the organization of our contribution and show its relevance with simulations and experiments over a set of use cases. Full article

Recent advances in nanomaterial design and synthesis has resulted in robust sensing systems that display superior analytical performance. The use of nanomaterials within sensors has accelerated new routes and opportunities for the detection of analytes or target molecules. Among others, carbon-based sensors have reported biocompatibility, better sensitivity, better selectivity and lower limits of detection to reveal a wide range of organic and inorganic molecules. Carbon nanomaterials are among the most extensively studied materials because of their unique properties spanning from the high specific surface area, high carrier mobility, high electrical conductivity, flexibility, and optical transparency fostering their use in sensing applications. In this paper, a comprehensive review has been made to cover recent developments in the field of carbon-based nanomaterials for sensing applications. The review describes nanomaterials like fullerenes, carbon onions, carbon quantum dots, nanodiamonds, carbon nanotubes, and graphene. Synthesis of these nanostructures has been discussed along with their functionalization methods. The recent application of all these nanomaterials in sensing applications has been highlighted for the principal applicative field and the future prospects and possibilities have been outlined. Full article

While the Internet increasingly permeates everyday life of individuals around the world, it becomes crucial to prevent unauthorized collection and abuse of personalized information. Internet anonymization software such as Tor is an important instrument to protect online privacy. However, due to the performance overhead caused by Tor, many Internet users refrain from using it. This causes a negative impact on the overall privacy provided by Tor, since it depends on the size of the user community and availability of shared resources. Detailed measurements about the performance of Tor are crucial for solving this issue. This paper presents comparative experiments on Tor latency and throughput for surfing to 500 popular websites from several locations around the world during the period of 28 days. Furthermore, we compare these measurements to critical latency thresholds gathered from web usability research, including our own user studies. Our results indicate that without massive future optimizations of Tor performance, it is unlikely that a larger part of Internet users would adopt it for everyday usage. This leads to fewer resources available to the Tor community than theoretically possible, and increases the exposure of privacy-concerned individuals. Furthermore, this could lead to an adoption barrier of similar privacy-enhancing technologies for a Future Internet. Full article