Virtual Clones Research Articles

Unlocking the potentials of digital twins for optimal healthcare delivery in Africa

Abstract Advances in big data analysis, the Internet of Things and simulation technology have led to a surge in interest in digital twin technology, which creates virtual clones of physical entities across several industries. The technological revolution with digital twins, incorporating Internet of Things, big data analysis and simulation technologies, holds the potential for predictive insights, real-time monitoring and increased operational efficiency across the healthcare industry. This paper explores the potential of digital twins to improve healthcare delivery and health outcomes in Africa. It examines their applications in various health sectors, explores their feasibility and highlights the potential challenges associated with their implementation while proposing sustainable recommendations.

Overcoming chemotherapy resistance in low-grade gliomas: A computational approach.

Low-grade gliomas are primary brain tumors that arise from glial cells and are usually treated with temozolomide (TMZ) as a chemotherapeutic option. They are often incurable, but patients have a prolonged survival. One of the shortcomings of the treatment is that patients eventually develop drug resistance. Recent findings show that persisters, cells that enter a dormancy state to resist treatment, play an important role in the development of resistance to TMZ. In this study we constructed a mathematical model of low-grade glioma response to TMZ incorporating a persister population. The model was able to describe the volumetric longitudinal dynamics, observed in routine FLAIR 3D sequences, of low-grade glioma patients acquiring TMZ resistance. We used the model to explore different TMZ administration protocols, first on virtual clones of real patients and afterwards on virtual patients preserving the relationships between parameters of real patients. In silico clinical trials showed that resistance development was deferred by protocols in which individual doses are administered after rest periods, rather than the 28-days cycle standard protocol. This led to median survival gains in virtual patients of more than 15 months when using resting periods between two and three weeks and agreed with recent experimental observations in animal models. Additionally, we tested adaptive variations of these new protocols, what showed a potential reduction in toxicity, but no survival gain. Our computational results highlight the need of further clinical trials that could obtain better results from treatment with TMZ in low grade gliomas.

Savonius wind turbine blade design and performance evaluation using ANN-based virtual clone: A new approach

The drag based Savonius wind turbine (SWT) has shown immense potential for renewable power generation in built-up areas under complex urban wind conditions. While a series of studies have been conducted on improving SWT's efficiency, optimal performance has yet to be achieved using traditional design approaches such as experimental and/or computational fluid dynamics methods. Recently, artificial intelligence and machine learning have been widely used in design optimization. As such, an ANN-based virtual clone can be an alternative to traditional design methods for wind turbine performance determination. Therefore, the main goal of this study is to investigate whether ANN-based virtual clones are capable of determining the performance of SWTs with a shorter timeframe and minimal resources compared to traditional methods. To achieve the objective, an ANN-based virtual clone model is developed. Two sets of data (computational and experimental) are used to validate and determine the efficacy of the proposed ANN-based virtual clone model. Using experimental data, the model's fidelity is over 98%. The proposed model produces results in one-fifth the time of the existing simulation (based on the combined ANN + GA metamodel) method. The model also reveals the location of the dataset's optimized point for augmenting the turbine's performance.

An internet of secure and private things: A service-oriented architecture

Low-cost networked IoT devices are fast becoming commonplace. From implanted medical devices to motion-activated surveillance cameras and from driverless smart cars to voice-operated home management systems, IoT devices continue to permeate further and deeper into our lives. However, this widespread adoption of IoT devices has also given rise to a wide range of security, privacy and trust issues that are unique to the IoT ecosystem. Conventional solutions are ill-suited for the IoT domain due to limited resources, network dynamics, and evolving trust boundaries. Hence, novel mechanisms are needed to address the specific challenges of the IoT landscape. To this end, we propose a user-centric cloud-based service that allows device owners to have fine-grained control over what kind and how much data is shared through their IoT devices. Our scheme builds on top of Intel Software Guard Extensions (SGX) to instantiate secure virtual clones (shadows) of actual devices in the cloud, substantially reducing the attack surface for IoT networks. Furthermore, a scalable infrastructure in the cloud allows us to deploy sophisticated policy enforcement and data scrubbing mechanisms on a per application basis giving users explicit control over data sharing. The presented approach requires little effort on part of device vendors and users as the service provider handles the bulk of the work. We demonstrate the effectiveness of our approach empirically by implementing the service on SGX hardware and deploying advanced data cleansing policies on device-generated data.

Fog of Social IoT: When the Fog Becomes Social

SIoT and FC are two stand-alone technological paradigms under the realm of the Future Internet. SIoT relies on the self-establishment and self-management of inter-thing social relationships, in order to guarantee scalability to large IoT networks composed of both human and non-human agents. FC extends cloud capabilities to the access network, in order to allow resource-poor IoT devices to support delay-sensitive applications. Motivated by these complementary features of the SIoT and FC models, in this article we propose their integration into the novel paradigm of the SoFT. Specifically, we provide the following three main contributions. After describing the SoFT paradigm, we discuss its introduction through a number of exemplary use cases. We describe the architecture and the main resource-management functions of the resulting virtualized SoFT technological platform. It merges the physical things at the IoT layer and their virtual clones at the Fog layer into a cyber-physical overlay network of social clones. As a proof-of-concept, we present the simulated performance of a small-scale SoFT prototype, and compare its energy-vs.-delay performance with the corresponding one of a state-of-the-art virtualization-free technological platform, which relies only on device-to-device (D2D) inter-thing communication.

Genetic variation, inbreeding and chemical exposure--combined effects in wildlife and critical considerations for ecotoxicology.

Exposure to environmental chemicals can have negative consequences for wildlife and even cause localized population extinctions. Resistance to chemical stress, however, can evolve and the mechanisms include desensitized target sites, reduced chemical uptake and increased metabolic detoxification and sequestration. Chemical resistance in wildlife populations can also arise independently of exposure and may be spread by gene flow between populations. Inbreeding-matings between closely related individuals-can have negative fitness consequences for natural populations, and there is evidence of inbreeding depression in many wildlife populations. In some cases, reduced fitness in inbred populations has been shown to be exacerbated under chemical stress. In chemical testing, both inbred and outbred laboratory animals are used and for human safety assessments, iso-genic strains (virtual clones) of mice and rats are often employed that reduce response variation, the number of animals used and associated costs. In contrast, for environmental risk assessment, strains of animals are often used that have been selectively bred to maintain heterozygosity, with the assumption that they are better able to predict adverse effects in wild, genetically variable, animals. This may not necessarily be the case however, as one outbred strain may not be representative of another or of a wild population. In this paper, we critically discuss relationships between genetic variation, inbreeding and chemical effects with the intention of seeking to support more effective chemical testing for the protection of wildlife.

An in silico investigation into the causes of telomere length heterogeneity and its implications for the Hayflick limit

In telomerase-negative cell populations the mean telomere length (TL) decreases with increasing population doubling number (PD). A critically small TL is believed to stop cell proliferation at a cell-, age- and species-specific PD thus defining the Hayflick limit. However, positively skewed TL distributions are broad compared to differences between initial and final mean TL and strongly overlap at middle and late PD, which is inconsistent with a limiting role of TL. We used computer-assisted modelling to define what set of premises may account for the above. Our model incorporates the following concepts. DNA end replication problem: telomeres loose 1 shortening unit (SU) upon each cell division. Free radical-caused TL decrease: telomeres experience random events resulting in the loss of a random SU number within a remaining TL. Stochasticity of gene expression and cell differentiation: cells experience random events inducing mitoses or committing cells to proliferation arrest, the latter option requiring a specified number of mitoses to be passed. Cells whose TL reaches 1 SU cannot divide. The proliferation kinetics of such virtual cells conforms to the transition probability model of cell cycle. When no committing events occur and at realistic SU estimates of the initial TL, maximal PD values far exceed the Hayflick limit observed in normal cells and are consistent with the crisis stage entered by transformed cells that have surpassed the Hayflick limit. At intermediate PD, symmetrical TL distributions are yielded. Upon introduction of committing events making the ratio of the rates of proliferating and committing events ( P/ C) range from 1.10 to 1.25, TL distributions at intermediate PD become positively skewed, and virtual cell clones show bimodal size distributions. At P/ C as high as 1.25 the majority of virtual cells at maximal PD contain telomeres with TL>1 SU. A 10% increase in P/ C within the 1.10–1.25 range produces a two-fold increase in the maximal PD, which can reach values of up to 25 observed in rodent and some human cells. Increasing the number of committed mitoses from 0 to 10 can increases PD to about 50 observed in human fibroblasts. Introduction of the random TL breakage makes the shapes of TL distributions quite dissimilar from those observed in real cells. Conclusions: Telomere length decrease is a correlate of cell proliferation that cannot alone account for the Hayflick limit, which primarily depends on parameters of cell population kinetics. Free radical damage influences the Hayflick limit not through TL but rather by affecting the ratio of the rates of events that commit cells to mitoses or to proliferation arrest.

Personal Virtual Humans — Inhabiting the TalkZone and beyond

One of the fundamental goals of graphics has always been to visually create a three-dimensional person that is indistinguishable from a real person. This target is only slightly short of being reached, as was demonstrated when Columbia Pictures released Final Fantasy in 2001, an animated science fiction film with high-definition emotive characters. Through what has been a cultural and technological convergence, we are now starting to see software tools and techniques that can generate life-like characters while not sacrificing the human judgement and artistic skills that are needed in character animation. Computer games, films, and the Internet are now starting to use virtual humans, which as our conclusion will show will become more realistic. However, a new challenge has been set — people now do not want to just play a computer game with a visually realistic character, or see a television programme with a vivid computer generated character — they want to see themselves in that computer game or film. The future is towards individuals having their own virtual clones, which they can utilise in computer-generated worlds an applications. This paper will discuss the advantages of having a personal computer-generated character, and also describe several systems that BTexact Technologies have successfully developed and deployed to generate them, as well as some of the applications for which they can be used. The paper will finish by glimpsing into the future of what we can expect to see in the next few years, with the advent of this new exciting technology.

Fishing in Africa: A Guide to War and Corruption , and: Small Wars, Small Mercies: Journeys in Africa's Disputed Nations (review)

96 Book Reviews Fishing in Africa: A Guide to War and Corruption Andrew Buckoke London: Picador, 1991. 227 pp. Small Wars, Small Mercies: Journeys in Africa's Disputed Nations Jeremy Harding London: Viking, 1993. 442 pp. + xxi. Using editorial prerogative, I thought I would introduce two books that may otherwise be overlooked, yet give firsthand accounts of the civil conflicts in the Horn in the 1980s and early 1990s. Buckoke and Harding have almost identical CVs: both British, both Africa-based freelance correspondents, and both worked for the Financial Times at some point. For Buckoke, fishing—with an actual rod and reel—was the pretext for him to venture beyond the well-trodden correspondents' pathways and observe unreported people and environments. His chapters on Ethiopia, Sudan, Southern Sudan, and Somalia describe the upheaval of families and the rupture of social production caused by war far away from the farcical antics of the government or rebel leaders—virtual clones with respect to their blatant disregard for human life. Harding, as part of his title (Small Mercies) insinuates, presents a more redemptive picture of Africa. Perhaps this is a reflection of the times in which he wrote his book, as many of the rebel groups had emerged victorious and thus Harding, like others, glosses over the capriciousness of war. Reminiscent of Thomas Keneally's Towards Asmara, Harding's chapter on Eritrea attempts to contextualize the struggle of the EPLF within superpower and Middle Eastern conflicts while glorifying the life, organization, and commitment of the rebels. Finally, both books are eminently readable, providing sharp insights that often elude those too versed in the polemics of the situations. Charles Schaefer Valparaiso University ...