671 research outputs found
Leveraging the Grid to Provide a Global Platform for Ubiquitous Computing Research
The requirement for distributed systems support for Ubicomp has led to the development of numerous platforms, each addressing a subset of the overall requirements of ubiquitous systems. In contrast, many other scientific disciplines have embraced the vision of a global distributed computing platform, i.e. the Grid. We believe that the Grid has the potential to evolve into an ideal platform for building ubiquitous computing applications. In this paper we explore in detail the areas of synergy between Grid computing and ubiquitous computing and highlight a series of research challenges in this space
Singly-fed shaped planar inverted-F antenna for circular polarization
© 2016 IEEE. We propose a singly-fed planar inverted-F antenna (PIFA), with double-shorting planes and a tapered patch for radiating circular polarization. FEKO® simulations are employed to optimize the geometry of the antenna. The antenna prototype resonates at 2.52GHz and has a measured impedance bandwidth of around 240MHz. The calculated 3dB axial ratio bandwidth falls within the impedance bandwidth, demonstrating satisfactory circular polarization characteristics
Techniques for RF localization of wireless capsule endoscopy
© 2016 IEEE. Location estimation of a wireless capsule endoscope at 400 MHz MICS band is implemented here using both RSSI and TOA-based techniques and their performance investigated. To improve the RSSI-based location estimation, a maximum likelihood (ML) estimation method is employed. For the TOA-based localization, FDTD coupled with continuous wavelet transform (CWT) is used to estimate the time of arrival and localization is performed using multilateration. The performances of the proposed localization algorithms are evaluated using a computational heterogeneous biological tissue phantom in the 402MHz-405MHz MICS band. Our investigations reveal that the accuracy obtained by TOA based method is superior to RSSI based estimates. It has been observed that the ML method substantially improves the accuracy of the RSSI-based location estimation
Conditional overexpression of TGFβ1 promotes pulmonary inflammation, apoptosis and mortality via TGFβR2 in the developing mouse lung
Formulation and evaluation of floating mucoadhesive alginate beads for targetingHelicobacter pylori
Objectives: There are various obstacles in the eradication of Helicobacter.pylori (H. pylori) infections, including low antibiotic levels and poor accessibility of the drug at the site of the infection. This study describes the preparation and characterisation of novel floating-mucoadhesive alginate beads loaded with clarithromycin (CMN) for delivery to the gastric mucosa to improve the eradication of this micro-organism.
Methods: Calcium alginate beads were prepared by ionotropic gelation. The formulation was modified through addition of oil and coating with chitosan in order to improve floating, mucoadhesion and modify drug release.
Key findings: SEM confirmed the sphericity of the beads with X-ray microtomography (XμMT) showing the 3D structure of the beads with the layered internal structure of the bead and the even distribution of the drug within the bead. This formulation combined two gastro-retentive strategies and these formulations produced excellent in vitro floating, mucoadhesive and drug release characteristics. Enhanced stability of the beads in phosphate buffer raises a potential for the modified formulations to be targeted to regions of higher pH within the gastrointestinal tract with a higher pH. Drug release from these beads was sustained through an unstirred mucin layer simulating in vivo conditions under which the H. pylori resides in the gastric mucosa.
Conclusions: This novel formulation will ensure retention for a longer period in the stomach than conventional formulations and control drug release, ensuring high local drug concentrations, leading to improved eradication of the bacteria
Study of collagen organization in cell-laden hydrogels and animal tissue samples for effective tissue engineering scaffolds
The interaction of biomaterials with biological systems is a complex process, that is triggered in response to implants and wounds. It is essential to understand the phases of wound healing response, particularly the interactions of immune cells such as macrophages and fibroblasts, with the local extracellular matrix which can influence implant acceptance or the restoration of the damaged wound site. Materials properties such as compressive modulus, surface geometry, functionalization, and topology can be tuned to modulate the inflammatory and fibrotic responses to wounds and implants. Naturally derived materials, such as alginate, are widely used biomaterials owing to their biocompatibility and the diverse crosslinking strategies that can be used for fabrication. Soft alginate gels can be synthesized after methacrylation to be relatively stable under physiological conditions, while retaining pH sensitivity, which can be useful in the treatment of chronic wounds. Studying the collagen response to NIH/3T3 fibroblasts encapsulated in these soft hydrogels can develop wound healing strategies to promote faster wound healing. The transition of collagen organization from aligned to isotropic states in the dually crosslinked stiffer methacrylated alginate (ALGMA) hydrogels shows promise towards the development of topical gels for wound care. Modifying the surface properties using arginine-like derivatives is effective in modulating the fibroblast response to implanted glass beads in SKH1-E mice. Collagen response to modified glass beads using SHG microscopy was evaluated using several factors such as collagen amount, secretion of collagen III, and organization of collagen. The albizziin modification showed both isotropic collagen organization as well similar collagen type III as unwounded skin. Furthermore, statistical analysis uncovered correlations between SHG derived parameters and the materials properties of the chemical modifiers. Collagen type III was correlated with the surface tension of the modifier, and an empirical equation was derived relating materials parameters with the observed collagen measurements. The effectiveness of diverse wound care strategies on shallow and deep wounds on porcine subjects was conducted using SHG microscopy. Treatment duration, as well as scaffold preparation were instrumental in reducing a scarring response and accelerating wound closure rates. By combining the understanding of wound healing in diverse tissue environments, with environmentally responsive wound dressings, it is possible to improve the quality of life for millions of patients across the world
Genetic regulation of glucoraphanin accumulation in Beneforté® broccoli
Diets rich in broccoli (Brassica oleracea var italica) have been associated with maintenance of cardiovascular health and reduction in risk of cancer. These health benefits have been
attributed to glucoraphanin that specifically accumulates in broccoli. The development of broccoli with enhanced concentrations of glucoraphanin may deliver greater health benefits.
Three high-glucoraphanin F1 broccoli hybrids were developed in independent programmes through genome introgression from the wild species Brassica villosa. Glucoraphanin and other metabolites were quantified in experimental field trials. Global SNP analyses quantified the differential extent of B. villosa introgression
The high-glucoraphanin broccoli hybrids contained 2.5–3 times the glucoraphanin content of standard hybrids due to enhanced sulphate assimilation and modifications in sulphur partitioning between sulphur-containing metabolites. All of the high-glucoraphanin hybrids possessed an introgressed B. villosa segment which contained a B. villosa Myb28 allele. Myb28
expression was increased in all of the high-glucoraphanin hybrids. Two high-glucoraphanin hybrids have been commercialised as Beneforte broccoli.
The study illustrates the translation of research on glucosinolate genetics from Arabidopsis to broccoli, the use of wild Brassica species to develop cultivars with potential consumer benefits, and the development of cultivars with contrasting concentrations of glucoraphanin for use in blinded human intervention studie
Evaluating maize genotype performance under low nitrogen conditions using RGB UAV phenotyping techniques
Maize is the most cultivated cereal in Africa in terms of land area and production, but low soil nitrogen availability often constrains yields. Developing new maize varieties with high and reliable yields using traditional crop breeding techniques in field conditions can be slow and costly. Remote sensing has become an important tool in the modernization of field-based high-throughput plant phenotyping (HTPP), providing faster gains towards the improvement of yield potential and adaptation to abiotic and biotic limiting conditions. We evaluated the performance of a set of remote sensing indices derived from red–green–blue (RGB) images along with field-based multispectral normalized difference vegetation index (NDVI) and leaf chlorophyll content (SPAD values) as phenotypic traits for assessing maize performance under managed low-nitrogen conditions. HTPP measurements were conducted from the ground and from an unmanned aerial vehicle (UAV). For the ground-level RGB indices, the strongest correlations to yield were observed with hue, greener green area (GGA), and a newly developed RGB HTPP index, NDLab (normalized difference Commission Internationale de I´Edairage (CIE)Lab index), while GGA and crop senescence index (CSI) correlated better with grain yield from the UAV. Regarding ground sensors, SPAD exhibited the closest correlation with grain yield, notably increasing in its correlation when measured in the vegetative stage. Additionally, we evaluated how different HTPP indices contributed to the explanation of yield in combination with agronomic data, such as anthesis silking interval (ASI), anthesis date (AD), and plant height (PH). Multivariate regression models, including RGB indices (R2 > 0.60), outperformed other models using only agronomic parameters or field sensors (R2 > 0.50), reinforcing RGB HTPP’s potential to improve yield assessments. Finally, we compared the low-N results to the same panel of 64 maize genotypes grown under optimal conditions, noting that only 11% of the total genotypes appeared in the highest yield producing quartile for both trials. Furthermore, we calculated the grain yield loss index (GYLI) for each genotype, which showed a large range of variability, suggesting that low-N performance is not necessarily exclusive of high productivity in optimal conditions.This research and APC was funded by Bill & Melinda Gates Foundation and USAID Stress Tolerant Maize for Africa program, grant number [OPP1134248], and the MAIZE CGIAR research program. The CGIAR Research Program MAIZE receives W1&W2 support from the Governments of Australia, Belgium, Canada, China, France, India, Japan, Korea, Mexico, Netherlands, New Zealand, Norway, Sweden, Switzerland, U.K., U.S., and the World Bank
Tissue thickness measurement tool for craniofacial reconstruction
Craniofacial Reconstruction is a method of recreating the appearance of the face on the skull of a deceased individual for identification purposes. Older clay methods of reconstruction are inaccurate, time consuming and inflexible. The tremendous increase in the processing power of the computers and rapid strides in visualization can be used to perform the reconstruction, saving time and providing greater accuracy and flexibility, without the necessity for a skillful modeler.;This thesis introduces our approach to computerized 3D craniofacial reconstruction. Three phases have been identified. The first phase of the project is to generate a facial tissue thickness database. In the second phase this database along with a 3D facial components database is to be used to generate a generic facial mask which is draped over the skull to recreate the facial appearance. This face is to be identified from a database of images in the third phase.;Tissue thickness measurements are necessary to generate the facial model over the skull. The thesis emphasis is on the first phase of the project. An automated facial tissue thickness measurement tool (TTMT) has been developed to populate this database
Efficient privacy preserving communication protocol for IOT applications
The proliferation of Internet of Things (IoT) devices has led to an unprecedented increase in data generation and communication, raising concerns about the security and privacy of transmitted information. This paper presents a novel Message Authentication Protocol (MAP) specifically designed for IoT devices, addressing the dual challenges of ensuring data integrity and preserving user privacy. The proposed protocol employs advanced cryptographic techniques to authenticate messages securely while incorporating privacy-preserving mechanisms to safeguard sensitive user information.The protocol utilizes a hybrid approach, combining symmetric and asymmetric cryptographic primitives to achieve efficient and robust message authentication. Symmetric key algorithms are employed for fast and lightweight authentication, ensuring minimal computational overhead for resource-constrained IoT devices. Additionally, asymmetric key techniques are integrated to facilitate secure key exchange and protect against key compromise.Privacy preservation is a paramount concern in IoT ecosystems, where devices often handle sensitive data. The protocol incorporates anonymization and differential privacy techniques to conceal the identity of users and the specific content of transmitted messages. This ensures that even if an adversary intercepts communication, extracting meaningful information about the users or their data remains a formidable challenge.To evaluate the effectiveness of the proposed protocol, we conducted comprehensive simulations and real-world experiments. The results demonstrate that the protocol achieves a balance between security, efficiency, and privacy preservation. It outperforms existing solutions in terms of computational efficiency and provides a robust defence against various common attacks, such as replay attacks and message tampering.In conclusion, the presented Secure and Efficient Message Authentication Protocol for IoT Devices with Privacy Preservation offers a viable solution to the evolving security and privacy challenges in IoT environments. By leveraging cryptographic techniques and privacy-preserving mechanisms, the protocol provides a strong foundation for safeguarding sensitive information while ensuring the integrity of communication in the vast and interconnected landscape of IoT devices
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