939 resultados para Integrity
Resumo:
Cloud computing is a currently developing revolution in information technology that is disturbing the way that individuals and corporate entities operate while enabling new distributed services that have not existed before. At the foundation of cloud computing is the broader concept of converged infrastructure and shared services. Security is often said to be a major concern of users considering migration to cloud computing. This article examines some of these security concerns and surveys recent research efforts in cryptography to provide new technical mechanisms suitable for the new scenarios of cloud computing. We consider techniques such as homomorphic encryption, searchable encryption, proofs of storage, and proofs of location. These techniques allow cloud computing users to benefit from cloud server processing capabilities while keeping their data encrypted; and to check independently the integrity and location of their data. Overall we are interested in how users may be able to maintain and verify their own security without having to rely on the trust of the cloud provider.
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The safe working lifetime of a structure in a corrosive or other harsh environment is frequently not limited by the material itself but rather by the integrity of the coating material. Advanced surface coatings are usually crosslinked organic polymers such as epoxies and polyurethanes which must not shrink, crack or degrade when exposed to environmental extremes. While standard test methods for environmental durability of coatings have been devised, the tests are structured more towards determining the end of life rather than in anticipation of degradation. We have been developing prognostic tools to anticipate coating failure by using a fundamental understanding of their degradation behaviour which, depending on the polymer structure, is mediated through hydrolytic or oxidation processes. Fourier transform infrared spectroscopy (FTIR) is a widely-used laboratory technique for the analysis of polymer degradation and with the development of portable FTIR spectrometers, new opportunities have arisen to measure polymer degradation non-destructively in the field. For IR reflectance sampling, both diffuse (scattered) and specular (direct) reflections can occur. The complexity in these spectra has provided interesting opportunities to study surface chemical and physical changes during paint curing, service abrasion and weathering, but has often required the use of advanced statistical analysis methods such as chemometrics to discern these changes. Results from our studies using this and related techniques and the technical challenges that have arisen will be presented.
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Network coding is a method for achieving channel capacity in networks. The key idea is to allow network routers to linearly mix packets as they traverse the network so that recipients receive linear combinations of packets. Network coded systems are vulnerable to pollution attacks where a single malicious node floods the network with bad packets and prevents the receiver from decoding correctly. Cryptographic defenses to these problems are based on homomorphic signatures and MACs. These proposals, however, cannot handle mixing of packets from multiple sources, which is needed to achieve the full benefits of network coding. In this paper we address integrity of multi-source mixing. We propose a security model for this setting and provide a generic construction.
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Contemporary course designers in schools and faculties of Education are finding themselves dancing to many tunes, arguably too many tunes, in order to have their initial teacher education courses accredited by external agencies whilst satisfying internal approval processes and, critically, maintaining the philosophical integrity of their programs and their institutional watermarks. The “tunes” here are the agendas driven by and the demands made by distinct independent agencies. The external agencies influencing Education include: TEQSA (Tertiary Education Quality and Standards Agency) which will assure alignment to the AQF (Australian Qualifications Framework); professional bodies such as AITSL (Australian Institute for Teaching and School Leadership) which now accredits all pre-service teacher Education courses across Australia and assures alignment with the Australian Professional Standards for Teachers; and the state and territory regulatory authorities that have an impact within a specific jurisdiction, for example, the Queensland College of Teachers (QCT) and the Teacher Registration Board of Western Australia (TRBWA). This paper – whose findings have been arrived at through a year-long OLT National Teaching Fellowship - will outline the complex and competing agendas currently at play and focus on the disjuncture evident in the fundamental defining of who is a “graduate.” It will also attempt to identify where there are synergies between the complex demands being made. It will argue that there are too many “tunes” and the task of finding a balance between compliance and delivering effective initial teacher education may not be possible because of the cacophony of their conflicting demands.
Resumo:
Senescence and genomic integrity are thought to be important barriers in the development of malignant lesions. Human fibroblasts undergo a limited number of cell divisions before entering an irreversible arrest, called senescence. Here we show that human mammary epithelial cells (HMECs) do not conform to this paradigm of senescence. In contrast to fibroblasts, HMECs exhibit an initial growth phase that is followed by a transient growth plateau (termed selection or M0; refs 3-5), from which proliferative cells emerge to undergo further population doublings (approximately 20-70), before entering a second growth plateau (previously termed senescence or M1; refs 4-6). We find that the first growth plateau exhibits characteristics of senescence but is not an insurmountable barrier to further growth. HMECs emerge from senescence, exhibit eroding telomeric sequences and ultimately enter telomere-based crisis to generate the types of chromosomal abnormalities seen in the earliest lesions of breast cancer. Growth past senescent barriers may be a pivotal event in the earliest steps of carcinogenesis, providing many genetic changes that predicate oncogenic evolution. The differences between epithelial cells and fibroblasts provide new insights into the mechanistic basis of neoplastic transformation.
Resumo:
An increasing number of countries are faced with an aging population increasingly needing healthcare services. For any e-health information system, the need for increased trust by such clients with potentially little knowledge of any security scheme involved is paramount. In addition notable scalability of any system has become a critical aspect of system design, development and ongoing management. Meanwhile cryptographic systems provide the security provisions needed for confidentiality, authentication, integrity and non-repudiation. Cryptographic key management, however, must be secure, yet efficient and effective in developing an attitude of trust in system users. Digital certificate-based Public Key Infrastructure has long been the technology of choice or availability for information security/assurance; however, there appears to be a notable lack of successful implementations and deployments globally. Moreover, recent issues with associated Certificate Authority security have damaged trust in these schemes. This paper proposes the adoption of a centralised public key registry structure, a non-certificate based scheme, for large scale e-health information systems. The proposed structure removes complex certificate management, revocation and a complex certificate validation structure while maintaining overall system security. Moreover, the registry concept may be easier for both healthcare professionals and patients to understand and trust.
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Enterprise resource planning (ERP) systems are rapidly being combined with “big data” analytics processes and publicly available “open data sets”, which are usually outside the arena of the enterprise, to expand activity through better service to current clients as well as identifying new opportunities. Moreover, these activities are now largely based around relevant software systems hosted in a “cloud computing” environment. However, the over 50- year old phrase related to mistrust in computer systems, namely “garbage in, garbage out” or “GIGO”, is used to describe problems of unqualified and unquestioning dependency on information systems. However, a more relevant GIGO interpretation arose sometime later, namely “garbage in, gospel out” signifying that with large scale information systems based around ERP and open datasets as well as “big data” analytics, particularly in a cloud environment, the ability to verify the authenticity and integrity of the data sets used may be almost impossible. In turn, this may easily result in decision making based upon questionable results which are unverifiable. Illicit “impersonation” of and modifications to legitimate data sets may become a reality while at the same time the ability to audit any derived results of analysis may be an important requirement, particularly in the public sector. The pressing need for enhancement of identity, reliability, authenticity and audit services, including naming and addressing services, in this emerging environment is discussed in this paper. Some current and appropriate technologies currently being offered are also examined. However, severe limitations in addressing the problems identified are found and the paper proposes further necessary research work for the area. (Note: This paper is based on an earlier unpublished paper/presentation “Identity, Addressing, Authenticity and Audit Requirements for Trust in ERP, Analytics and Big/Open Data in a ‘Cloud’ Computing Environment: A Review and Proposal” presented to the Department of Accounting and IT, College of Management, National Chung Chen University, 20 November 2013.)
Resumo:
In this chapter, we discuss four related areas of cryptology, namely, authentication, hashing, message authentication codes (MACs), and digital signatures. These topics represent active and growing research topics in cryptology. Space limitations allow us to concentrate only on the essential aspects of each topic. The bibliography is intended to supplement our survey. We have selected those items which providean overview of the current state of knowledge in the above areas. Authentication deals with the problem of providing assurance to a receiver that a communicated message originates from a particular transmitter, and that the received message has the same content as the transmitted message. A typical authentication scenario occurs in computer networks, where the identity of two communicating entities is established by means of authentication. Hashing is concerned with the problem of providing a relatively short digest–fingerprint of a much longer message or electronic document. A hashing function must satisfy (at least) the critical requirement that the fingerprints of two distinct messages are distinct. Hashing functions have numerous applications in cryptology. They are often used as primitives to construct other cryptographic functions. MACs are symmetric key primitives that provide message integrity against active spoofing by appending a cryptographic checksum to a message that is verifiable only by the intended recipient of the message. Message authentication is one of the most important ways of ensuring the integrity of information that is transferred by electronic means. Digital signatures provide electronic equivalents of handwritten signatures. They preserve the essential features of handwritten signatures and can be used to sign electronic documents. Digital signatures can potentially be used in legal contexts.
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Design Pressure Test 2013 was a full-day intensive design immersion creative event run on Saturday 3 August 2013, at the QUT Faculty of Creative Industries J Block Design Lab Workshop in Brisbane, Australia, for 25 self-selected high-achieving junior and middle school (year 5-9) students, as part of the Queensland Academies ‘Young Scholars’ Program. Facilitated by tertiary interior design, fashion design and industrial design educators, technicians and six tertiary interior design and fashion design students, the workshop explored design process, environmental impact, the material properties and structural integrity of cardboard, construction techniques, and the production and evaluation of furniture design prototypes. This action research study aimed to facilitate an awareness in young people, of the role and scope of design within our society, the environmental ramifications of design decisions, and the value of design thinking skills in generating strategies to solve basic to complex challenges. It also aimed to investigate the value of collaboration between junior and middle school students, tertiary design educators and students and industry professionals in design awareness, and inspiring post-secondary pathways and idea generation for education. During the creative event, students utilised mathematics skills and developed sketching, making, communication, presentation and collaboration skills to improve their design process, while considering social, cultural and environmental opportunities. Through a series of hands-on collaborative design experiments, participants explored in teams of five, the opportunities available using cardboard as a material – inspiring both functional and aesthetic design solutions. Underpinned by the State Library of Queensland Design Minds Website ‘inquire, ideate and implement’ model of design thinking, the experiments culminated in the development of a detailed client brief, the design and fabrication of a furniture item for seating, and then a team presentation of prototypes to a panel of judges from the professions of architecture, interior design and industrial design, viewed also by parents. The final test for structural integrity was measured by the hoisting down of an adult body weight onto the fabricated seat. The workshop was filmed for the television program ‘Totally Wild’ for dissemination nationally (over 200,000 viewing audience) of the value of design and the Design Minds model to a wider target youth audience.
Resumo:
The role of Bone Tissue Engineering in the field of Regenerative Medicine has been the topic of substantial research over the past two decades. Technological advances have improved orthopaedic implants and surgical techniques for bone reconstruction. However, improvements in surgical techniques to reconstruct bone have been limited by the paucity of autologous materials available and donor site morbidity. Recent advances in the development of biomaterials have provided attractive alternatives to bone grafting expanding the surgical options for restoring the form and function of injured bone. Specifically, novel bioactive (second generation) biomaterials have been developed that are characterised by controlled action and reaction to the host tissue environment, whilst exhibiting controlled chemical breakdown and resorption with an ultimate replacement by regenerating tissue. Future generations of biomaterials (third generation) are designed to be not only osteo- conductive but also osteoinductive, i.e. to stimulate regeneration of host tissues by combining tissue engineer- ing and in situ tissue regeneration methods with a focus on novel applications. These techniques will lead to novel possibilities for tissue regeneration and repair. At present, tissue engineered constructs that may find future use as bone grafts for complex skeletal defects, whether from post-traumatic, degenerative, neoplastic or congenital/developmental “origin” require osseous reconstruction to ensure structural and functional integrity. Engineering functional bone using combinations of cells, scaffolds and bioactive factors is a promising strategy and a particular feature for future development in the area of hybrid materials which are able to exhibit suitable biomimetic and mechanical properties. This review will discuss the state of the art in this field and what we can expect from future generations of bone regeneration concepts.
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High power, high frequency pulsed electric fields known as pulsed power (PP) has been applied recently in biology and medicine. However, little attention has been paid to investigate the application of pulse power in musculoskeletal system and its possible effect on functional behavior and biomechanical properties of bone tissue. This paper presents the first research investigating whether or not PP can be applied safely on bone tissue as a stimuli and what will be the possible effect of these signals on the characteristics of cortical bone by comparing the mechanical properties of this type of bone pre and post expose to PP and in comparison with the control samples. A positive buck‑boost converter was applied to generate adjustable high voltage, high frequency pulses (up to 500 V and 10 kHz). The functional behavior of bone in response to pulse power excitation was elucidated by applying compressive loading until failure. The stiffness, failure stress (strength) and the total fracture energy (bone toughness) were determined as a measure of the main bone characteristics. Furthermore, an ultrasonic technique was applied to determine and comprise bone elasticity before and after pulse power stimulation. The elastic property of cortical bone samples appeared to remain unchanged following exposure to pulse power excitation for all three orthogonal directions obtained from ultrasonic technique and similarly from the compression test. Nevertheless, the compressive strength and toughness of bone samples were increased when they were exposed to 66 h of high power pulsed electromagnetic field compared to the control samples. As the toughness and the strength of the cortical bone tissue are directly associated with the quality and integrity of the collagen matrix whereas its stiffness is primarily related to bone mineral content these overall results may address that although, the pulse power stimulation can influence the arrangement or the quality of the collagen network causing the bone strength and toughness augmentation, it apparently did not affect the mineral phase of the cortical bone material. The results also confirmed that the indirect application of high power pulsed electric field at 500 V and 10 kHz through capacitive coupling method was safe and did not destroy the bone tissue construction.
Resumo:
Murine models with modified gene function as a result of N-ethyl-N-nitrosourea (ENU) mutagenesis have been used to study phenotypes resulting from genetic change. This study investigated genetic factors associated with red blood cell (RBC) physiology and structural integrity that may impact on blood component storage and transfusion outcome. Forward and reverse genetic approaches were employed with pedigrees of ENU-treated mice using a homozygous recessive breeding strategy. In a “forward genetic” approach, pedigree selection was based upon identification of an altered phenotype followed by exome sequencing to identify a causative mutation. In a second strategy, a “reverse genetic” approach based on selection of pedigrees with mutations in genes of interest was utilised and, following breeding to homozygosity, phenotype assessed. Thirty-three pedigrees were screened by the forward genetic approach. One pedigree demonstrated reticulocytosis, microcytic anaemia and thrombocytosis. Exome sequencing revealed a novel single nucleotide variation (SNV) in Ank1 encoding the RBC structural protein ankyrin-1 and the pedigree was designated Ank1EX34. The reticulocytosis and microcytic anaemia observed in the Ank1EX34 pedigree were similar to clinical features of hereditary spherocytosis in humans. For the reverse genetic approach three pedigrees with different point mutations in Spnb1 encoding RBC protein spectrin-1β, and one pedigree with a mutation in Epb4.1, encoding band 4.1 were selected for study. When bred to homozygosity two of the spectrin-1β pedigrees (a, b) demonstrated increased RBC count, haemoglobin (Hb) and haematocrit (HCT). The third Spnb1 mutation (spectrin-1β c) and mutation in Epb4.1 (band 4.1) did not significantly affect the haematological phenotype, despite these two mutations having a PolyPhen score predicting the mutation may be damaging. Exome sequencing allows rapid identification of causative mutations and development of databases of mutations predicted to be disruptive. These tools require further refinement but provide new approaches to the study of genetically defined changes that may impact on blood component storage and transfusion outcome.
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Preserving the integrity of the skin's outermost layer (the epidermis) is vital for humans to thrive in hostile surroundings. Covering the entire body, the epidermis forms a thin but impenetrable cellular cordon that repels external assaults and blocks escape of water and electrolytes from within. This structure exists in a perpetual state of regeneration where the production of new cellular subunits at the base of the epidermis is offset by the release of terminally differentiated corneocytes from the surface. It is becoming increasingly clear that proteases hold vital roles in assembling and maintaining the epidermal barrier. More than 30 proteases are expressed by keratinocytes or infiltrating immune cells and the activity of each must be maintained within narrow limits and confined to the correct time and place. Accordingly, over- or under-exertion of proteolytic activity is a common factor in a multitude of skin disorders that range in severity from relatively mild to life-threatening. This review explores the current state of knowledge on the involvement of proteases in skin diseases and the latest findings from proteomic and transcriptomic studies focused on uncovering novel (patho)physiological roles for these enzymes.
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Large, osseous, segmental defects heal poorly. Muscle has a propensity to form bone when exposed to an osteogenic stimulus such as that provided by transfer and expression of cDNA encoding bone morphogenetic protein-2 (BMP-2). The present study evaluated the ability of genetically modified, autologous muscle to heal large cranial defects in rats. Autologous grafts (8 mm � 2 mm) were punched from the biceps femoris muscle and transduced intraoperatively with recombinant adenovirus vector containing human BMP-2 or green fluorescent protein cDNA. While the muscle biopsies were incubating with the vector, a central parietal 8 mm defect was surgically created in the calvarium of the same animal. The gene-activated muscle graft was then implanted into the cranial defect. After 8 weeks, crania were examined radiographically, histologically, and by micro-computed tomography and dual energy X-ray absorptiometry. Although none of the defects were completely healed in this time, muscle grafts expressing BMP-2 deposited more than twice as much new bone as controls. Histology confirmed the anatomical integrity of the newly formed bone, which was comparable in thickness and mineral density to the original cranial bone. This study confirms the in vivo osteogenic properties of genetically modified muscle and suggests novel strategies for healing bone. � 2011 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 30:1095–1102, 2012
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Programmed cell death-associated genes, especially antiapoptosis-related genes have been reported to confer tolerance to a wide range of biotic and abiotic stresses in dicotyledonous plants such as tobacco (Nicotiana tabacum L.) and tomato (Solanum lycopersicum L.). This is the first time the antiapoptotic gene SfIAP was transformed into a monocotyledonous representative: rice (Oryza sativa L.). Transgenic rice strains expressing SfIAP were generated by the Agrobacterium-mediated transformation method and rice embryogenic calli, and assessed for their ability to confer tolerance to salt stress at both the seedling and reproductive stages using a combination of molecular, agronomical, physiological and biochemical techniques. The results show that plants expressing SfIAP have higher salt tolerance levels in comparison to the wild-type and vector controls. By preventing cell death at the onset of salt stress and maintaining the cell membrane’s integrity, SfIAP transgenic rice plants can retain plant water status, ion homeostasis, photosynthetic efficiency and growth to combat salinity successfully.