Journal articles on the topic 'Inaccurate mimicry'
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Reinhold, K., and L. Engqvist. "Inaccurate mimicry and predator ecology." Journal of Theoretical Biology 229, no. 4 (August 2004): 433–34. http://dx.doi.org/10.1016/j.jtbi.2004.04.030.
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Taylor, Christopher H., Tom Reader, and Francis Gilbert. "Why many Batesian mimics are inaccurate: evidence from hoverfly colour patterns." Proceedings of the Royal Society B: Biological Sciences 283, no. 1842 (November 16, 2016): 20161585. http://dx.doi.org/10.1098/rspb.2016.1585.
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Mimicry is considered a classic example of the elaborate adaptations that natural selection can produce, yet often similarity between Batesian (harmless) mimics and their unpalatable models is far from perfect. Variation in mimetic accuracy is a puzzle, as natural selection should favour mimics that are hardest to distinguish from their models. Numerous hypotheses exist to explain the persistence of inaccurate mimics, but most have rarely or never been tested against empirical observations from wild populations. One reason for this is the difficulty in measuring pattern similarity, a key aspect of mimicry. Here, we use a recently developed method, based on the distance transform of binary images, to quantify pattern similarity both within and among species for a group of hoverflies and their hymenopteran models. This allowed us to test three key hypotheses regarding inaccurate mimicry. Firstly, we tested the prediction that selection should be more relaxed in less accurate mimics, but found that levels of phenotypic variation are similar across most hoverfly species. Secondly, we found no evidence that mimics have to compromise between accuracy to multiple model species. However, we did find that darker-coloured hoverflies are less accurate mimics, which could lead to a trade-off between mimicry and thermoregulation in temperate regions. Our results shed light on a classic problem concerning the limitations of natural selection.
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Pekár, Stano. "Is inaccurate mimicry ancestral to accurate in myrmecomorphic spiders (Araneae)?" Biological Journal of the Linnean Society 113, no. 1 (June 4, 2014): 97–111. http://dx.doi.org/10.1111/bij.12287.
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Ihalainen, Eira, Hannah M. Rowland, Michael P. Speed, Graeme D. Ruxton, and Johanna Mappes. "Prey community structure affects how predators select for Müllerian mimicry." Proceedings of the Royal Society B: Biological Sciences 279, no. 1736 (January 11, 2012): 2099–105. http://dx.doi.org/10.1098/rspb.2011.2360.
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Müllerian mimicry describes the close resemblance between aposematic prey species; it is thought to be beneficial because sharing a warning signal decreases the mortality caused by sampling by inexperienced predators learning to avoid the signal. It has been hypothesized that selection for mimicry is strongest in multi-species prey communities where predators are more prone to misidentify the prey than in simple communities. In this study, wild great tits ( Parus major ) foraged from either simple (few prey appearances) or complex (several prey appearances) artificial prey communities where a specific model prey was always present. Owing to slower learning, the model did suffer higher mortality in complex communities when the birds were inexperienced. However, in a subsequent generalization test to potential mimics of the model prey (a continuum of signal accuracy), only birds that had foraged from simple communities selected against inaccurate mimics. Therefore, accurate mimicry is more likely to evolve in simple communities even though predator avoidance learning is slower in complex communities. For mimicry to evolve, prey species must have a common predator; the effective community consists of the predator's diet. In diverse environments, the limited diets of specialist predators could create ‘simple community pockets’ where accurate mimicry is selected for.
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Nelson, Ximena J. "A Predator's Perspective of the Accuracy of Ant Mimicry in Spiders." Psyche: A Journal of Entomology 2012 (2012): 1–5. http://dx.doi.org/10.1155/2012/168549.
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Among spiders, resemblance of ants (myrmecomorphy) usually involves the Batesian mimicry, in which the spider coopts the morphological and behavioural characteristics of ants to deceive ant-averse predators. Nevertheless, the degree of resemblance between mimics and ants varies considerably. I usedPortia fimbriata,a jumping spider (Salticidae) with exceptional eyesight that specialises on preying on salticids, to test predator perception of the accuracy of ant mimicry.Portia fimbriata’s response to ants (Oecophylla smaragdina), accurate ant-like salticids (Synageles occidentalis), and inaccurate ant-like salticids (females ofMyrmarachne bakeriand sexually dimorphic males ofM. bakeri, which have enlarged chelicerae) was assessed.Portia fimbriataexhibited graded aversion in accordance with the accuracy of resemblance to ants (O. smaragdina>S. occidentalis> femaleM. bakeri> maleM. bakeri). These results support the hypothesis that ant resemblance confers protection from visual predators, but to varying degrees depending on signal accuracy.
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Pekár, Stano, Martin Jarab, Lutz Fromhage, and Marie E. Herberstein. "Is the Evolution of Inaccurate Mimicry a Result of Selection by a Suite of Predators? A Case Study Using Myrmecomorphic Spiders." American Naturalist 178, no. 1 (July 2011): 124–34. http://dx.doi.org/10.1086/660287.
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Johnstone, Rufus A. "The evolution of inaccurate mimics." Nature 418, no. 6897 (August 2002): 524–26. http://dx.doi.org/10.1038/nature00845.
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Hauber, Márk E., Csaba Moskát, and Miklós Bán. "Experimental shift in hosts' acceptance threshold of inaccurate-mimic brood parasite eggs." Biology Letters 2, no. 2 (January 17, 2006): 177–80. http://dx.doi.org/10.1098/rsbl.2005.0438.
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Hosts are expected to evolve resistance strategies that efficiently detect and resist exposure to virulent parasites and pathogens. When recognition is not error-proof, the acceptance threshold used by hosts to recognize parasites should be context dependent and become more restrictive with increasing predictability of parasitism. Here, we demonstrate that decisions of great reed warblers Acrocephalus arundinaceus to reject parasitism by the common cuckoo Cuculus canorus vary adaptively within a single egg-laying bout. Hosts typically accept one of their own eggs with experimentally added spots and the background colour left visible. In contrast, hosts reject such spotted eggs when individuals had been previously exposed to and rejected one of their own eggs whose background colour had been entirely masked. These results support patterns of adaptive modulation of antiparasitic strategies through shifts in the acceptance threshold of hosts and suggest a critical role for experience in the discrimination decisions between inaccurate-mimic parasite eggs and hosts' own eggs.
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GU, JE-AN. "CAN f(R) GRAVITY MIMIC GENERAL RELATIVITY?" International Journal of Modern Physics: Conference Series 10 (January 2012): 63–68. http://dx.doi.org/10.1142/s2010194512005764.
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We discuss the stability of the general-relativity (GR) limit in modified theories of gravity, particularly the f(R) theory. The problem of approximating the higher-order differential equations in modified gravity with the Einstein equations (2nd-order differential equations) in GR is elaborated. We demonstrate this problem with a heuristic example involving a simple ordinary differential equation. With this example we further present the iteration method that may serve as a better approximation for solving the equation, meanwhile providing a criterion for assessing the validity of the approximation. We then discuss our previous numerical analyses of the early-time evolution of the cosmological perturbations in f(R) gravity, following the similar ideas demonstrated by the heuristic example. The results of the analyses indicated the possible instability of the GR limit that might make the GR approximation inaccurate in describing the evolution of the cosmological perturbations in the long run.
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Abdullah, Johari Yap, Abdul Manaf Abdullah, Helmi Hadi, Adam Husein, and Zainul Ahmad Rajion. "Comparison of STL skull models produced using open-source software versus commercial software." Rapid Prototyping Journal 25, no. 10 (November 11, 2019): 1585–91. http://dx.doi.org/10.1108/rpj-08-2018-0206.
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Purpose This paper aims to compare the automatic segmentation of medical data and conversion to stereolithography (STL) skull models using open-source software versus commercial software. Design/methodology/approach Both open-source and commercial software used automatic segmentation and post-processing of the data without user intervention, thus avoiding human error. Detailed steps were provided for comparisons and easier to be repeated by other researchers. The results of segmentation, which were converted to STL format were compared using geometric analysis. Findings STL skull models produced using open-source software are comparable with the one produced using commercial software. A comparison of STL skull model produced using InVesalius with STL skull model produced using MIMICS resulted in an average dice similarity coefficient (DSC) of 97.6 ± 0.04 per cent and Hausdorff distance (HD) of 0.01 ± 0.005 mm. Inter-rater study for repeatability on MIMICS software yielded an average DSC of 100 per cent and HD of 0. Social implications The application of open-source software will benefit the small research institutions or hospitals to produce and virtualise three-dimensional model of the skulls for teaching or clinical purposes without having to purchase expensive commercial software. It is also easily reproduceable by other researchers. Originality/value This study is one of the first comparative evaluations of an open-source software with propriety commercial software in producing accurate STL skull models. Inaccurate STL models can lead to inaccurate pre-operative planning or unfit implant.
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Gauthreaux, Kathryn, Tyler A. Bonnett, Lilah M. Besser, Willa D. Brenowitz, Merilee Teylan, Charles Mock, Yen-Chi Chen, et al. "Concordance of Clinical Alzheimer Diagnosis and Neuropathological Features at Autopsy." Journal of Neuropathology & Experimental Neurology 79, no. 5 (February 24, 2020): 465–73. http://dx.doi.org/10.1093/jnen/nlaa014.
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Abstract It remains unclear what clinical features inform the accuracy of a clinical diagnosis of Alzheimer disease (AD). Data were obtained from the National Alzheimer’s Coordinating Center to compare clinical and neuropathologic features among participants who did or did not have Alzheimer disease neuropathologic changes (ADNC) at autopsy. Participants (1854) had a clinical Alzheimer dementia diagnosis and ADNC at autopsy (Confirmed-AD), 204 participants had an AD diagnosis and no ADNC (AD-Mimics), and 253 participants had no AD diagnosis and ADNC (Unidentified-AD). Compared to Confirmed-AD participants, AD-Mimics had less severe cognitive impairment, while Unidentified-AD participants displayed more parkinsonian signs, depression, and behavioral problems. This study highlights the importance of developing a complete panel of biomarkers as a tool to inform clinical diagnoses, as clinical phenotypes that are typically associated with diseases other than AD may result in inaccurate diagnoses.
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Levitt, Michael R., Jeffrey G. Ojemann, and John Kuratani. "Insular epilepsy masquerading as multifocal cortical epilepsy as proven by depth electrode." Journal of Neurosurgery: Pediatrics 5, no. 4 (April 2010): 365–67. http://dx.doi.org/10.3171/2009.11.peds09169.
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The insular cortex is an uncommon epileptogenic location from which complex partial seizures may arise. Seizure activity in insular epilepsy may mimic temporal, parietal, or other cortical areas. Semiology, electroencephalography, and even surface electrocorticography recordings may falsely localize other cortical foci, leading to inaccurate diagnosis and treatment. The use of insular depth electrodes allows more precise localization of seizure foci. The authors describe the case of a young girl with seizures falsely localized to the cortex, with foci arising from the insula, as proven by depth electrode recordings. Resection of the insula yielded seizure control.
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Thomson, Dana R., Douglas R. Leasure, Tomas Bird, Nikos Tzavidis, and Andrew J. Tatem. "How accurate are WorldPop-Global-Unconstrained gridded population data at the cell-level?: A simulation analysis in urban Namibia." PLOS ONE 17, no. 7 (July 21, 2022): e0271504. http://dx.doi.org/10.1371/journal.pone.0271504.
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Disaggregated population counts are needed to calculate health, economic, and development indicators in Low- and Middle-Income Countries (LMICs), especially in settings of rapid urbanisation. Censuses are often outdated and inaccurate in LMIC settings, and rarely disaggregated at fine geographic scale. Modelled gridded population datasets derived from census data have become widely used by development researchers and practitioners; however, accuracy in these datasets are evaluated at the spatial scale of model input data which is generally courser than the neighbourhood or cell-level scale of many applications. We simulate a realistic synthetic 2016 population in Khomas, Namibia, a majority urban region, and introduce several realistic levels of outdatedness (over 15 years) and inaccuracy in slum, non-slum, and rural areas. We aggregate the synthetic populations by census and administrative boundaries (to mimic census data), resulting in 32 gridded population datasets that are typical of LMIC settings using the WorldPop-Global-Unconstrained gridded population approach. We evaluate the cell-level accuracy of these gridded population datasets using the original synthetic population as a reference. In our simulation, we found large cell-level errors, particularly in slum cells. These were driven by the averaging of population densities in large areal units before model training. Age, accuracy, and aggregation of the input data also played a role in these errors. We suggest incorporating finer-scale training data into gridded population models generally, and WorldPop-Global-Unconstrained in particular (e.g., from routine household surveys or slum community population counts), and use of new building footprint datasets as a covariate to improve cell-level accuracy (as done in some new WorldPop-Global-Constrained datasets). It is important to measure accuracy of gridded population datasets at spatial scales more consistent with how the data are being applied, especially if they are to be used for monitoring key development indicators at neighbourhood scales within cities.
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Bishop, Edith Sylvia, Jon L. Hall, Ian Handel, Dylan Neil Clements, and John Ryan. "Sequential drilling and drill angulation reduce the accuracy of drill hole start location in a synthetic bone model." Veterinary Record 184, no. 12 (January 31, 2019): 383. http://dx.doi.org/10.1136/vr.104897.
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The accuracy of drill hole location is critical for implant placement in orthopaedic surgery. Increasing drill bit size sequentially has been suggested as a method for improving the accuracy of drill hole start location. The aim of this study was to determine whether sequential drilling or drill angulation would alter accuracy of drill hole start location. Three specialist veterinary surgeons drilled holes in synthetic bone models either directly, or with sequentially increasing drill bit sizes. Drilling was performed at 0o, 10o and 20o to perpendicular to the bone models. Three synthetic bone models were used to mimic canine cancellous and cortical bones. Sequential drilling resulted in greater inaccuracy in drill hole location when assessing all drilling angles together. There was no influence of surgeon or synthetic bone density on drilling accuracy. The combination of drill angulation and sequential drilling increased inaccuracy in drill hole start location. We conclude that sequential drilling decreased accuracy of drill hole location in the synthetic bone model when drilling was angled. Inaccuracy associated with the drill hole start location should be taken into account when performing surgery, although the magnitude of inaccuracy is low when compared with other sources of error such as angulation.
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Mignano, Salvatore E., and Daniel H. Russell. "Nodular Vascular Transformation of the Lymph Node Sinuses Mimicking Sarcomatoid Change in Renal Cell Carcinoma: A Potential Diagnostic Pitfall." International Journal of Surgical Pathology 28, no. 6 (May 10, 2020): 637–42. http://dx.doi.org/10.1177/1066896920916243.
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Vascular transformation of the lymph node sinuses (VTS) is an uncommon phenomenon that is believed to occur secondary to obstruction of efferent lymphatics, frequently occuring in retroperitoneal lymph nodes draining cancer. The nodular subtype of VTS, in particular, can mimic metastatic cancer, such as metastatic renal cell carcinoma with sarcomatoid differentiation, potentially resulting in inaccurate tumor grading and/or staging. We present a case of nodular VTS mimicking metastatic renal cell carcinoma with sarcomatoid differentiation in a patient with high-grade clear cell renal cell carcinoma, and explore the relevant differential diagnosis. Awareness of VTS is essential to avoid misdiagnosis of this benign and curative condition.
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Sheehan, Michael J., and H. Kern Reeve. "Evolutionarily stable investments in recognition systems explain patterns of discrimination failure and success." Philosophical Transactions of the Royal Society B: Biological Sciences 375, no. 1802 (May 18, 2020): 20190465. http://dx.doi.org/10.1098/rstb.2019.0465.
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Many animals are able to perform recognition feats that astound us—such as a rodent recognizing kin it has never met. Yet in other contexts, animals appear clueless as when reed warblers rear cuckoo chicks that bear no resemblance to their own species. Failures of recognition when it would seem adaptive have been especially puzzling. Here, we present a simple tug-of-war game theory model examining how individuals should optimally invest in affecting the accuracy of discrimination between desirable and undesirable recipients. In the game, discriminating individuals (operators) and desirable and undesirable recipients (targets and mimics, respectively) can all invest effort into their own preferred outcome. We demonstrate that stable inaccurate recognition will arise when undesirable recipients have large fitness gains from inaccurate recognition relative to the pay-offs that the other two parties receive from accurate recognition. The probability of accurate recognition is often determined by just the relative pay-offs to the desirable and undesirable recipients, rather than to the discriminator. Our results provide a new lens on long-standing puzzles including a lack of nepotism in social insect colonies, tolerance of brood parasites and male birds caring for extra-pair young in their nests, which our model suggests should often lack accurate discrimination. This article is part of the theme issue ‘Signal detection theory in recognition systems: from evolving models to experimental tests'.
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Mó, Inês, Ivo J. Sabino, Duarte de Melo-Diogo, Rita Lima-Sousa, Cátia G. Alves, and Ilídio J. Correia. "The importance of spheroids in analyzing nanomedicine efficacy." Nanomedicine 15, no. 15 (June 2020): 1513–25. http://dx.doi.org/10.2217/nnm-2020-0054.
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The use of nanomedicines for cancer treatment holds a great potential due to their improved efficacy and safety. During the nanomedicine preclinical in vitro evaluation stage, these are mainly tested on cell culture monolayers. However, these 2D models are an unrealistic representation of the in vivo tumors, leading to an inaccurate screening of the candidate formulations. To address this problem, spheroids are emerging as an additional tool to validate the efficacy of new therapeutics due to the ability of these 3D in vitro cancer models to mimic the key features displayed by in vivo solid tumors. In this review, the application of spheroids for the evaluation of nanomedicines’ physicochemical properties and therapeutic efficacy is discussed.
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Gigras, Piyush G., and Bamin Khomami. "An Evaluation of Single-Segment Reptation Theories for Linear Entangled Polymeric Systems." Applied Rheology 14, no. 1 (February 1, 2004): 22–32. http://dx.doi.org/10.1515/arh-2004-0002.
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Abstract A short synopsis of the recently proposed reptation models based on the Doi and Edwards’ tube concept is provided. Specifically, a critical examination of a number of theories like the “simplified” Mead-Larson-Doi model, the Öttinger model and the “Double Convection Reptation” model of Marrucci and coworkers has been performed. These models have been chosen due the fact that are computationally tractable as they mimic the chain dynamics in the tube using unconnected portions of the chain in a mean field way. Overall, we find each of these models to be equally competitive barring a few exceptional cases, where it is suspected that certain critical assumptions, made during the formulation of the model could lead to inaccurate predictions under transient or Lagrangian unsteady settings.
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Ricci, Stefano. "Open-Source FPGA Coprocessor for the Doppler Emulation of Moving Fluids." Micromachines 12, no. 12 (December 12, 2021): 1549. http://dx.doi.org/10.3390/mi12121549.
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Embedded systems are nowadays employed in a wide range of application, and their capability to implement calculation-intensive algorithms is growing quickly and constantly. This result is obtained by the exploitation of powerful embedded processors that are often connected to coprocessors optimized for a particular application. This work presents an open-source coprocessor dedicated to the real-time generation of a synthetic signal that mimics the echoes produced by a moving fluid when investigated by ultrasounds. The coprocessor is implemented in a Field Programmable Gate Array (FPGA) device and integrated in an embedded system. The system can replace the complex and inaccurate flow-rigs employed in laboratorial tests of Doppler ultrasound systems and methods. This paper details the coprocessor and its standard interfaces, and shows how it can be integrated in the wider architecture of an embedded system. Experiments showed its capability to emulate a fluid flowing in a pipe when investigated by an echographic Doppler system.
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Cao, Heting, and Xingquan Zuo. "Supply Chain Inventory Coordination under Uncertain Demand via Combining Monte Carlo Simulation and Fitness Inheritance PSO." International Journal of Swarm Intelligence Research 6, no. 1 (January 2015): 1–22. http://dx.doi.org/10.4018/ijsir.2015010101.
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Supply chain coordination consists of multiple aspects, among which inventory coordination is the most widely used in practice. Inventory coordination is challenging due to the uncertainty of customers' demand. Existing researches typically assume that the demand is either a deterministic constant or a stochastic variable following a known distribution function. However, the former cannot reflect the practical costumers' demand, and the later make the model inaccurate when the demand distribution is ambiguous or highly variable. In this paper, the authors propose a Monte Carlo simulation model of such problem, which can mimic the inventory changing procedure of a supply chain with uncertain demand following an arbitrary distribution function. Then, a PSO is combined with the simulation model to achieve a coordination decision scheme to minimize the total inventory cost. Experiments show that their approach is able to produce a high quality solution within a short computational time and outperforms comparative approaches.
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Singh, S. R., H. J. Fan, and L. D. Marks. "Quantitative surface damage studies by H.R.E.M." Proceedings, annual meeting, Electron Microscopy Society of America 47 (August 6, 1989): 632–33. http://dx.doi.org/10.1017/s042482010015513x.
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Since the original observation that the surfaces of materials undergo radiation damage in the electron microscope similar to that observed by more conventional surface science techniques there has been substantial interest in understanding these phenomena in more detail; for a review see. For instance, surface damage in a microscope mimics damage in the space environment due to the solar wind and electron beam lithographic operations.However, purely qualitative experiments that have been done in the past are inadequate. In addition, many experiments performed in conventional microscopes may be inaccurate. What is needed is careful quantitative analysis including comparisons of the behavior in UHV versus that in a conventional microscope. In this paper we will present results of quantitative analysis which clearly demonstrate that the phenomena of importance are diffusion controlled; more detailed presentations of the data have been published elsewhere.As an illustration of the results, Figure 1 shows a plot of the shrinkage of a single, roughly spherical particle of WO3 versus time (dose) driven by oxygen desorption from the surface.
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Szepes, Zoltán, Mariann Dobra, Csaba Góg, Edit Zábrák, Éva Makula, László Tiszlavicz, Tamás Kiss, et al. "Pancreatic cancer or autoimmune pancreatitis: endosonography as a diagnostic reviser." Orvosi Hetilap 154, no. 2 (January 2013): 62–68. http://dx.doi.org/10.1556/oh.2013.29513.
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Conventional radiologic imaging (abdominal ultrasound, computer tomography) used in the differential diagnosis of post-hepatic jaundice can frequently provide inaccurate diagnosis. Inflammatory lesions may mimic neoplastic processes and malignancy may be accompanied by perifocal inflammation resulting in histological misdiagnosis. Furthermore, chronic and autoimmune pancreatitis are associated with an increased risk for pancreatic cancer. Radial endosonography has become a markedly important method in the imaging of the pancreas. It has a crucial role in the diagnosis and staging of pancreatic cancer. The authors present three cases where the diagnosis of pancreatic cancer determined by conventional imaging techniques (abdominal ultrasound, computer tomography, endoscopic retrograde cholangiopancreatography) was excluded or confirmed by the radial endosonography. The authors conclude that radial endosonography is an essential complementary method among imaging techniques of the pancreas and in tumor staging. Application of that may prevent unnecessary surgeries, which is obviously useful for patients and cost effective for health care providers. Orv. Hetil., 2013, 154, 62–68.
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Fernandez-Carro, Estibaliz, Maricke Angenent, Tamara Gracia-Cazaña, Yolanda Gilaberte, Clara Alcaine, and Jesús Ciriza. "Modeling an Optimal 3D Skin-on-Chip within Microfluidic Devices for Pharmacological Studies." Pharmaceutics 14, no. 7 (July 6, 2022): 1417. http://dx.doi.org/10.3390/pharmaceutics14071417.
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Preclinical research remains hampered by an inadequate representation of human tissue environments which results in inaccurate predictions of a drug candidate’s effects and target’s suitability. While human 2D and 3D cell cultures and organoids have been extensively improved to mimic the precise structure and function of human tissues, major challenges persist since only few of these models adequately represent the complexity of human tissues. The development of skin-on-chip technology has allowed the transition from static 3D cultures to dynamic 3D cultures resembling human physiology. The integration of vasculature, immune system, or the resident microbiome in the next generation of SoC, with continuous detection of changes in metabolism, would potentially overcome the current limitations, providing reliable and robust results and mimicking the complex human skin. This review aims to provide an overview of the biological skin constituents and mechanical requirements that should be incorporated in a human skin-on-chip, permitting pharmacological, toxicological, and cosmetic tests closer to reality.
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Ayoade, Folusakin, Pradeep Mada, Andrew Joel Chandranesan, and Mohammed Alam. "Sporotrichoid Skin Infection Caused by Nocardia brasiliensis in a Kidney Transplant Patient." Diseases 6, no. 3 (July 25, 2018): 68. http://dx.doi.org/10.3390/diseases6030068.
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Prompt and accurate diagnosis of Nocardia skin infections is important in immunocompromised hosts, especially transplant patients. The sporotrichoid form, which is otherwise known as the lymphocutaneous form of Nocardia skin involvement, can mimic other conditions, including those caused by fungi, mycobacteria, spirochetes, parasites and other bacteria. Delayed or inaccurate diagnosis and treatment of Nocardia skin infections in transplant patients could lead to dissemination of disease and other poor outcomes. Nocardia brasiliensis is a rare cause of lymphocutaneous nocardiosis in solid organ transplant patients with only two other cases reported to our knowledge. This case describes a middle-aged man, who presented 16 years post kidney transplant. He developed a sporotrichoid lesion on his upper extremity one week after gardening. Ultrasound showed a 35-cm abscess tract on his forearm, which was subsequently drained. Nocardia brasiliensis was isolated from pus culture and he was treated successfully with amoxicillin/clavulanate for 6 months. A review of the relevant literature is included.
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Agarwal, Rinky, Manasi Tripathi, Anuja Patil, and Namrata Sharma. "Rare atypical presentation of phacolytic glaucoma as non-resolving microbial keratitis with endophthalmitis." BMJ Case Reports 12, no. 9 (September 2019): e231616. http://dx.doi.org/10.1136/bcr-2019-231616.
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Phacolytic glaucoma (PLG) is a rare complication of hypermature senile cataract. Delayed presentation of PLG may make its diagnosis and management difficult and worsen its prognosis. A woman aged 75 years complaining of sleep disturbing pain and inaccurate projection of rays oculus dextrus (OD) was referred to our centre for management of non-resolving microbial keratitis with endophthalmitis. Ultrasound biomicroscopy revealed 360° peripheral anterior synechiae, swollen crystalline lens and hyperechoic granules filling anterior chamber. A diagnosis of PLG and lens-induced uveitis was made and cataract was extracted after control of intraocular pressure (IOP). The patient was left aphakic. There was complete resolution of pain after surgery and at 3 months follow-up the IOP was controlled without any antiglaucoma medications. Rarely, secondary corneal opacification from long-standing pathological changes in PLG may mimic non-resolving microbial keratitis with endophthalmitis and requires a high index of suspicion for appropriate diagnosis and management.
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Sheen, Seung Heon, Egor Larionov, and Dinesh K. Pai. "Volume Preserving Simulation of Soft Tissue with Skin." Proceedings of the ACM on Computer Graphics and Interactive Techniques 4, no. 3 (September 22, 2021): 1–23. http://dx.doi.org/10.1145/3480143.
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Simulation of human soft tissues in contact with their environment is essential in many fields, including visual effects and apparel design. Biological tissues are nearly incompressible. However, standard methods employ compressible elasticity models and achieve incompressibility indirectly by setting Poisson's ratio to be close to 0.5. This approach can produce results that are plausible qualitatively but inaccurate quantatively. This approach also causes numerical instabilities and locking in coarse discretizations or otherwise poses a prohibitive restriction on the size of the time step. We propose a novel approach to alleviate these issues by replacing indirect volume preservation using Poisson's ratios with direct enforcement of zonal volume constraints, while controlling fine-scale volumetric deformation through a cell-wise compression penalty. To increase realism, we propose an epidermis model to mimic the dramatically higher surface stiffness on real skinned bodies. We demonstrate that our method produces stable realistic deformations with precise volume preservation but without locking artifacts. Due to the volume preservation not being tied to mesh discretization, our method also allows a resolution consistent simulation of incompressible materials. Our method improves the stability of the standard neo-Hookean model and the general compression recovery in the Stable neo-Hookean model.
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Et.al, JIBUM JUNG. "Use of Human Motion Data to Train Wearable Robots." Turkish Journal of Computer and Mathematics Education (TURCOMAT) 12, no. 6 (April 11, 2021): 807–11. http://dx.doi.org/10.17762/turcomat.v12i6.2100.
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Development of wearable robots is accelerating. Walking robots mimic human behavior and must operate without accidents. Human motion data are needed to train these robots. We developed a system for extracting human motion data and displaying them graphically.We extracted motion data using a Perception Neuron motion capture system and used the Unity engine for the simulation. Several experiments were performed to demonstrate the accuracy of the extracted motion data.Of the various methods used to collect human motion data, markerless motion capture is highly inaccurate, while optical motion capture is very expensive, requiring several high-resolution cameras and a large number of markers. Motion capture using a magnetic field sensor is subject to environmental interference. Therefore, we used an inertial motion capture system. Each movement sequence involved four and was repeated 10 times. The data were stored and standardized. The motions of three individuals were compared to those of a reference person; the similarity exceeded 90% in all cases.
Our rehabilitation robot accurately simulated human movements: individually tailored wearable robots could be designed based on our data. Safe and stable robot operation can be verified in advance via simulation. Walking stability can be increased using walking robots trained via machine learning algorithms.
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Baildam, A. D., G. T. Williams, and P. F. Schofield. "Abdominal Lymphoma - the Place for Surgery." Journal of the Royal Society of Medicine 82, no. 11 (November 1989): 657–60. http://dx.doi.org/10.1177/014107688908201108.
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Gastrointestinal lymphoma (GIL) is rare but may be cured by surgery and chemotherapy. Because symptoms frequently mimic common abdominal conditions, presentation is often to a surgeon. Fiftyfive patients with GIL were treated between 1975 and 1984: all underwent operations before the correct diagnosis was made, 22 (40%) as emergencies. Misdiagnosis in 23 (42%) led to a delay in correct treatment of ≥ 6 months from the start of symptoms: in 17 (31%) the delay was ≥ one year. Endoscopy and radiology were inaccurate and suggested peptic ulceration, Crohn's disease or irritable bowel syndrome. The site of disease was usually stomach and duodenum (26, 47%) or ileum and jejunum (29, 53%). The extent of surgical resection was associated with survival at ≥3 years - in 16 (29%) who underwent ‘complete resection’ 14 survived, but only one of 28 survived when the operation was limited to diagnostic biopsy (P < 0.0001). Most deaths occurred within one year of operation, commonlyfrom perforation or haematemesis from residual mural disease during chemotherapy. In 5 of 11 patients who had biopsy only, CT scans suggested localized disease, and ‘complete resection’ was achieved at a second laparotomy. Complete resection should be attempted wherever possible before chemotherapy. The place for surgeons with experience is clearly central to the management of this disease.
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Du, Jun, Daoxing Guo, Bangning Zhang, and Yunxia Su. "A Robust Cooperative Spectrum Sensing-Assisted Multiuser Resource Allocation Scheme." Mathematical Problems in Engineering 2015 (2015): 1–12. http://dx.doi.org/10.1155/2015/839698.
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Cognitive radio (CR), which is proposed as a solution for spectrum scarcity, imposes some threats to the network. One severe attack to cognitive radio network is the primary user emulation attack (PUEA), in which an attacker may transmit its signal with high power or mimic specific features of the primary user’s signal to prevent secondary users from accessing the licensed spectrum. In this paper, we study a subcarrier and power allocation problem for orthogonal frequency division multiple access-(OFDMA-) based CR systems in the presence of PUEA. To maximize the system throughput while keeping the interference introduced to the primary user (PU) below given thresholds with a certain probability, a joint design of a robust cooperative spectrum sensing and a resource allocation scheme is proposed. In the proposed scheme, the inaccurate classification of PU signals and PUEA signals provided by robust cooperative spectrum sensing is utilized by resource scheduling module. To further exploit the underutilized spectrum bands, we also evaluate the performance of the proposed scheme in the hybrid overlay/underlay spectrum access mechanism. Numerical results demonstrate the effectiveness of the proposed scheme compared to conventional scheme regardless of the number of SUs or the kind of spectrum access mechanism being used.
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Bayer, B., B. Sissolak, M. Duerkop, M. von Stosch, and G. Striedner. "The shortcomings of accurate rate estimations in cultivation processes and a solution for precise and robust process modeling." Bioprocess and Biosystems Engineering 43, no. 2 (September 20, 2019): 169–78. http://dx.doi.org/10.1007/s00449-019-02214-6.
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Abstract The accurate estimation of cell growth or the substrate consumption rate is crucial for the understanding of the current state of a bioprocess. Rates unveil the actual cell status, making them valuable for quality-by-design concepts. However, in bioprocesses, the real rates are commonly not accessible due to analytical errors. We simulated Escherichia coli fed-batch fermentations, sampled at four different intervals and added five levels of noise to mimic analytical inaccuracy. We computed stepwise integral estimations with and without using moving average estimations, and smoothing spline interpolations to compare the accuracy and precision of each method to calculate the rates. We demonstrate that stepwise integration results in low accuracy and precision, especially at higher sampling frequencies. Contrary, a simple smoothing spline function displayed both the highest accuracy and precision regardless of the chosen sampling interval. Based on this, we tested three different options for substrate uptake rate estimations.
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Duchowny, Michael S. "Atonic Seizures." Pediatrics In Review 9, no. 2 (August 1, 1987): 43–49. http://dx.doi.org/10.1542/pir.9.2.43.
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Seizures consisting of rapidly arrested movement are relatively common and account for approximately 12% of all episodes. Atonic seizure is the preferred designation for this form of clinical presentation, although more descriptive terms such as "drop attack" and "epileptic fall" are also popular. Many clinicians still use the term "akinetic seizure," but this is inaccurate because attacks of behavioral immobility with preserved muscle tone and consciousness cannot be differentiated from absence seizures. Furthermore, it is unlikely that neurophysiologic mechanisms can arrest behavior without altering muscle tone or compromising consciousness. The accurate diagnosis and management of atonic seizures constitutes an important challenge for the practicing pediatrician. Whereas grand mal and petit mal seizures are well-known manifestations of epilepsy in childhood, seizures limited to the loss of muscle tone are more likely to go unrecognized. The large variety of nonepileptic conditions that mimic atonic seizures further adds to the difficulties of correct identification. DESCRIPTION Atonic seizures show considerable variation in presentation and severity. Typically, without warning, the voluntary muscles synchronously increase and then lose resting tone. No aura precedes these muscular changes. Both the myoclonic and atonic seizure components can cause the child to collapse limply to the ground. Massive myoclonus and loss of tone may even precipitate a violent fall from a sitting position (Fig 1), resulting in craniofacial injury, skull fracture, facial laceration, or dental trauma.
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Weissmann, José, Angela Jannini Weissmann, and Srinivas Gona. "Computerized Equipment Replacement Methodology." Transportation Research Record: Journal of the Transportation Research Board 1824, no. 1 (January 2003): 77–83. http://dx.doi.org/10.3141/1824-09.
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The Texas Department of Transportation (DOT) owns and maintains an active fleet inventory of approximately 17,000 units and replaces about 10% of them annually. Any methodology that can improve Texas DOT’s replacement procedures could potentially save millions of dollars. Private and public agencies do not routinely use life-cycle cost as a replacement criterion because the only way to automate inspection of thousands of life-cycle cost histories has been to define an acceptability threshold for annualized costs. Most fleet managers consider this practice too inaccurate. The most relevant information provided by a lifecycle cost graph is its trend. Units whose life-cycle costs have been increasing longer or at a faster rate should have higher replacement priority. The trend score concept allows a computer to mimic replacement decisions made by a person visually inspecting a series of life-cycle cost histories. A new economically sound methodology for assisting with equipment replacement at Texas DOT is presented. This new method takes full advantage of Texas DOT’s comprehensive equipment operating system database, can prioritize the units on the basis of comparisons among all units within any desired class of equipment, and uses life-cycle cost trends as a replacement criterion. This methodology was implemented through the Texas Equipment Replacement Model, a menudriven software that allows the fleet manager to efficiently apply the methodology.
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Wang, Yan, Guichen Lu, and Jiang Du. "Calibration and prediction for the inexact SIR model." Mathematical Biosciences and Engineering 19, no. 3 (2022): 2800–2818. http://dx.doi.org/10.3934/mbe.2022128.
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<abstract><p>A Susceptible Infective Recovered (SIR) model is usually unable to mimic the actual epidemiological system exactly. The reasons for this inaccuracy include observation errors and model discrepancies due to assumptions and simplifications made by the SIR model. Hence, this work proposes calibration and prediction methods for the SIR model with a one-time reported number of infected cases. Given that the observation errors of the reported data are assumed to be heteroscedastic, we propose two predictors to predict the actual epidemiological system by modeling the model discrepancy through a Gaussian Process model. One is the calibrated SIR model, and the other one is the discrepancy-corrected predictor, which integrates the calibrated SIR model with the Gaussian Process predictor to solve the model discrepancy. A wild bootstrap method quantifies the two predictors' uncertainty, while two numerical studies assess the performance of the proposed method. The numerical results show that, the proposed predictors outperform the existing ones and the prediction accuracy of the discrepancy-corrected predictor is improved by at least $ 49.95\% $.</p></abstract>
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Zhegallo, A. V., and I. A. Basul. "Paired Model Experiment “Believe/Do Not Believe” — The Ability to Highlight Non-Verbal Signs Of Reliability/Unreliability of the Information Reported." Experimental Psychology (Russia) 15, no. 3 (2022): 79–87. http://dx.doi.org/10.17759/exppsy.2022150306.
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As markers of reliability/inaccuracy of the reported information, there have been repeated attempts to use the partial facial features identified by experts. Our research proposes a transition to analysis at the level of automatically identified integral mimic patterns. To solve this problem, a model paired experiment was conducted in which participants had to repeatedly make a decision to tell the truth/lie. The analysis of facial expressions was performed by automatically calculating the coordinates of key points and further extracting integral facial expression patterns using the method of principal components. At the level of loads of the main components, signs of making a decision “to lie/tell the truth” for the sample as a whole and for individual subjects are highlighted. It was found that holistic patterns of facial expressions associated with the reliability/unreliability of the reported information at “low rates” are characterized by high individual variability. As a direction for further research on facial expressions, a transition to the study of the individual repertoire of integral patterns of facial expressions is proposed.
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Wearden, John H., and Jordan Wehrman. "Modelling Feedback Effects on the Production of Short Time Intervals." Timing & Time Perception 10, no. 1 (May 31, 2021): 56–74. http://dx.doi.org/10.1163/22134468-bja10038.
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Abstract People produced time intervals of 500 to 1250 ms, with accurate feedback in ms provided after each production. The mean times produced tracked the target times closely, and the coefficient of variation (standard deviation/mean) declined with increasing target time. The mean absolute change from one trial to another, and its standard deviation, measures of trial-by-trial change, also increased with target time. A model of feedback was fitted to all four measures. It assumed that the time produced resulted from a combination of a scalar timing process and a non-timing process. Although the non-timing process was on average invariant with target time, the timing process was assumed to be sensitive to feedback, in two different ways. If the previous production was close to the target the model repeated it (a repeat process), but if it was further away the next production was adjusted by an amount related to the discrepancy between the previous production and the target (an adjust process). The balance between the two was governed by a threshold, which was on average constant, and it was further assumed that the relative variability of the repeat process was lower than that of the adjust process. The model produced output which fitted three of the four measures well (average deviation of 3 or 4%) but fitted the standard deviation of change less well. Reducing the magnitude of the non-timing process produced output which conformed approximately to scalar timing, and the model could also mimic data resulting from the provision of inaccurate feedback.
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Li, Chia-Wei, Ai-Ling Hsu, Chi-Wen C. Huang, Shih-Hung Yang, Chien-Yuan Lin, Charng-Chyi Shieh, and Wing P. Chan. "Reliability of Synthetic Brain MRI for Assessment of Ischemic Stroke with Phantom Validation of a Relaxation Time Determination Method." Journal of Clinical Medicine 9, no. 6 (June 14, 2020): 1857. http://dx.doi.org/10.3390/jcm9061857.
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The reliability of relaxation time measures in synthetic magnetic resonance images (MRIs) of homemade phantoms were validated, and the diagnostic suitability of synthetic imaging was compared to that of conventional MRIs for detecting ischemic lesions. Phantoms filled with aqueous cupric-sulfate (CuSO4) were designed to mimic spin-lattice (T1) and spin-spin (T2) relaxation properties and were used to compare their accuracies and stabilities between synthetic and conventional scans of various brain tissues. To validate the accuracy of synthetic imaging in ischemic stroke diagnoses, the synthetic and clinical scans of 18 patients with ischemic stroke were compared, and the quantitative contrast-to-noise ratios (CNRs) were measured, using the Friedman test to determine significance in differences. Results using the phantoms showed no significant differences in the interday and intersession synthetic quantitative T1 and T2 values. However, between synthetic and referenced T1 and T2 values, differences were larger for longer relaxation times, showing that image intensities in synthetic scans are relatively inaccurate in the cerebrospinal fluid (CSF). Similarly, CNRs in CSF regions of stroke patients were significantly different on synthetic T2-weighted and T2-fluid-attenuated inversion recovery images. In contrast, differences in stroke lesions were insignificant between the two. Therefore, interday and intersession synthetic T1 and T2 values are highly reliable, and discrepancies in synthetic T1 and T2 relaxation times and image contrasts in CSF regions do not affect stroke lesion diagnoses. Additionally, quantitative relaxation times from synthetic images allow better estimations of ischemic stroke onset time, consequently increasing confidence in synthetic MRIs as diagnostic tools for ischemic stroke.
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Broomell, Stephen B., Gabrielle Wong-Parodi, Rebecca E. Morss, and Julie L. Demuth. "Do We Know Our Own Tornado Season? A Psychological Investigation of Perceived Tornado Likelihood in the Southeast United States." Weather, Climate, and Society 12, no. 4 (October 2020): 771–88. http://dx.doi.org/10.1175/wcas-d-20-0030.1.
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AbstractReducing fatalities from tornadoes in the southeastern United States requires considering multiple societal factors, including the risk perceptions that influence how people interpret tornado forecasts and warnings and make protective decisions. This study investigates perceptions of tornado risk in the southeastern United States, operationalized as judgments of tornado likelihood. While it is possible that residents of the Southeast could learn about tornado likelihood in their region from observing the local environment, cognitive-ecological theory from psychology suggests that such judgments of likelihood can be inaccurate, even if other aspects of local knowledge are accurate. This study analyzes data from a survey that elicited different groups’ judgments of tornado likelihood associated with different seasons, times of day, and storm system types. Results are presented from a representative sample of Southeastern residents and are compared with a sample of tornado experts (who have extensive knowledge about the likelihood of Southeastern tornadoes) and a representative sample of Great Plains residents. Overall, the analysis finds that many members of the Southeastern public deviate from the expert sample on tornado likelihood, especially for winter and overnight tornadoes. These deviations from expert opinion mimic the judgments of the Great Plains public. This study demonstrates how psychological theory and a decision science approach can be used to identify potential gaps in public knowledge about hazardous weather risks, and it reveals several such potential gaps. Further research is needed to understand the reasons for deviations between public and expert judgments, evaluate their effects on protective decision-making, and develop strategies to address them.
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Aootaphao, Sorapong, Saowapak S. Thongvigitmanee, Jartuwat Rajruangrabin, Chalinee Thanasupsombat, Tanapon Srivongsa, and Pairash Thajchayapong. "X-Ray Scatter Correction on Soft Tissue Images for Portable Cone Beam CT." BioMed Research International 2016 (2016): 1–12. http://dx.doi.org/10.1155/2016/3262795.
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Soft tissue images from portable cone beam computed tomography (CBCT) scanners can be used for diagnosis and detection of tumor, cancer, intracerebral hemorrhage, and so forth. Due to large field of view, X-ray scattering which is the main cause of artifacts degrades image quality, such as cupping artifacts, CT number inaccuracy, and low contrast, especially on soft tissue images. In this work, we propose the X-ray scatter correction method for improving soft tissue images. The X-ray scatter correction scheme to estimate X-ray scatter signals is based on the deconvolution technique using the maximum likelihood estimation maximization (MLEM) method. The scatter kernels are obtained by simulating the PMMA sheet on the Monte Carlo simulation (MCS) software. In the experiment, we used the QRM phantom to quantitatively compare with fan-beam CT (FBCT) data in terms of CT number values, contrast to noise ratio, cupping artifacts, and low contrast detectability. Moreover, the PH3 angiography phantom was also used to mimic human soft tissues in the brain. The reconstructed images with our proposed scatter correction show significant improvement on image quality. Thus the proposed scatter correction technique has high potential to detect soft tissues in the brain.
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Kammoun, E. S., E. Nardini, and G. Risaliti. "Testing the accuracy of reflection-based supermassive black hole spin measurements in AGN." Astronomy & Astrophysics 614 (June 2018): A44. http://dx.doi.org/10.1051/0004-6361/201732377.
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Context. X-ray reflection is a very powerful method to assess the spin of supermassive black holes (SMBHs) in active galactic nuclei (AGN), yet this technique is not universally accepted. Indeed, complex reprocessing (absorption, scattering) of the intrinsic spectra along the line of sight can mimic the relativistic effects on which the spin measure is based. Aims. In this work, we test the reliability of SMBH spin measurements that can currently be achieved through the simulations of high-quality XMM-Newton and NuSTAR spectra. Methods. Each member of our group simulated ten spectra with multiple components that are typically seen in AGN, such as warm and (partial-covering) neutral absorbers, relativistic and distant reflection, and thermal emission. The resulting spectra were blindly analysed by the other two members. Results. Out of the 60 fits, 42 turn out to be physically accurate when compared to the input model. The SMBH spin is retrieved with success in 31 cases, some of which (9) are even found among formally inaccurate fits (although with looser constraints). We show that, at the high signal-to-noise ratio assumed in our simulations, neither the complexity of the multi-layer, partial-covering absorber nor the input value of the spin are the major drivers of our results. The height of the X-ray source (in a lamp-post geometry) instead plays a crucial role in recovering the spin. In particular, a success rate of 16 out of 16 is found among the accurate fits for a dimensionless spin parameter larger than 0.8 and a lamp-post height lower than five gravitational radii.
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Demczar, D. J., A. N. Nafziger, and J. S. Bertino. "Pharmacokinetics of gentamicin at traditional versus high doses: implications for once-daily aminoglycoside dosing." Antimicrobial Agents and Chemotherapy 41, no. 5 (May 1997): 1115–19. http://dx.doi.org/10.1128/aac.41.5.1115.
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Two doses of gentamicin (2 and 7 mg/kg of body weight) were administered to 11 healthy volunteers in a randomized, crossover single-dose study to compare their pharmacokinetics. Doses were infused over 1 h with a syringe infusion pump, and 14 concentrations in sera were obtained over an 8-h period. Concentration in serum versus time data were fitted to a two-compartment pharmacokinetic model. In addition, to mimic the clinical setting, subjects' data were fitted by the Sawchuk-Zaske method. Distributional and postdistributional peak concentrations, along with the last obtained concentration in serum, were utilized to compare the following pharmacokinetic variables: volume of distribution at steady state (Vss), half-life, clearance (CL), and maximum concentration in serum (Cmax). With two-compartment pharmacokinetic fitting, significant differences in distribution half-life (average, 21.8 and 41.6 min [P < or = 0.05]) and gentamicin CL (76.6 +/- 6.6 and 67.2 +/- 4.2 ml/min/1.73 m2 [P < or = 0.001]) were found between traditional-dose and high-dose groups, respectively. When the data for concentrations in sera were fitted to a one-compartment pharmacokinetic model by using either the distributional or the postdistributional Cmax, statistically significant differences (P < or = 0.001) were found between Vss, half-life, CL, and Cmax values for both dosage groups. The results show that the pharmacokinetics of gentamicin at a large dose differ significantly from those at the traditional dose. This information has direct implications for once-daily aminoglycoside (ODA) literature when the Cmax values reported are distributional and therefore show falsely high Cmax/MIC ratio estimates. In addition, ODA nomogram dosing tools developed with distributional Cmax values are probably inaccurate.
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Zheng, Yang, Guanghua Xu, Yixin Li, and Wei Qiang. "Improved online decomposition of non-stationary electromyogram via signal enhancement using a neuron resonance model: a simulation study." Journal of Neural Engineering 19, no. 2 (April 1, 2022): 026030. http://dx.doi.org/10.1088/1741-2552/ac5f1b.
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Abstract Objective. Motor unit (MU) discharge information obtained via the online electromyogram (EMG) decomposition has shown promising prospects in multiple applications. However, the nonstationarity of EMG signals caused by the rotation (recruitment-derecruitment) of MUs and the variation of MU action potentials (MUAP) can significantly degrade the online decomposition performance. This study aimed to develop an independent component analysis-based online decomposition method that can accommodate the nonstationarity of EMG signals. Approach. The EMG nonstationarity can make the separation vectors obtained beforehand inaccurate, resulting in the reduced amplitudes of the peaks corresponding to firing events in the source signal (independent component) and then the decreased accuracy of firing events. Therefore, we utilized the FitzHugh–Nagumo (FHN) resonance model to enhance the firing peaks in the source signal in order to improve the decomposition accuracy. A two-session approach was used with the offline session to extract the separation vectors and train the FHN models. In the online session, the source signal was estimated and further processed using the FHN model before detecting the firing events in a real-time manner. The proposed method was tested on simulated EMG signals, in which MU rotation and MUAP variation were involved to mimic the nonstationarity of EMG recordings. Main results. Compared with the conventional method, the proposed method can improve the decomposition accuracy significantly (88.70% ± 4.17% vs. 92.43% ± 2.79%) by enhancing the firing peaks, and more importantly, the improvement was more prominent when the EMG signal had stronger background noises (87.00% ± 3.70% vs. 91.66% ± 2.63%). Conclusions. Our results demonstrated the effectiveness of the proposed method to utilize the FHN model to improve the online decomposition performance on the nonstationary EMG signals. Further development of our method has the potential to improve the performance of the neural decoding system that utilizes the MU discharge information and promote its application in the neural-machine interface.
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MURIANA, PETER M., HUIYING HOU, and RAKESH K. SINGH. "A Flow-Injection System for Studying Heat Inactivation of Listeria monocytogenes and Salmonella enteritidis in Liquid Whole Egg." Journal of Food Protection 59, no. 2 (February 1, 1996): 121–26. http://dx.doi.org/10.4315/0362-028x-59.2.121.
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A flow-injection system was devised to mimic continuous flow-through pasteurization systems for laboratory thermal inactivation studies. Air bubbles were introduced into the sample stream to create separate moving segments (plugs) of liquid stream during pasteurization while residence time was adjusted by a combination of pump speed and column length. The method was used to obtain thermal inactivation data for Listeria monocytogenes Scott A and Salmonella enteritidis ATCC 13076 in liquid whole eggs at different temperatures and heating times. Thermal inactivation of L. monocytogenes using the capillary tube method (Zcap = 7.3°C) gave results comparable to those obtained with the flow-injection system (Zflow = 7.2°C). The flow-injection system also was used to examine thermal inactivation of S. enteritidis (SE) grown in either tryptic soy broth (TSB) or egg yolk medium (EYM) before inoculation into liquid whole egg (LWE). D-values were obtained by regression analysis and the data showed that SE grown in EYM gave D-values 15 to 120% higher than those obtained for SE grown in TSB. Thermal inactivation studies performed with S. enteritidis grown in commercial broth media may therefore inaccurately represent thermal resistance of S. enteritidis grown in liquid or shell raw egg as may occur in egg-associated outbreaks. The continuous flow-injection system described herein may be adapted to study continuous flow pasteurization processes not easily examined by the traditional capillary tube method.
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Gibson, Richard L. "Radiation from seismic sources in cased and cemented boreholes." GEOPHYSICS 59, no. 4 (April 1994): 518–33. http://dx.doi.org/10.1190/1.1443613.
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Far‐field, stationary phase approximations are often used to study the radiation of P‐ and S‐waves from seismic sources located in boreholes, usually with an assumption of low frequency and in application to uncased boreholes. These two assumptions allow explicit analytical results for the radiation patterns to be derived, as boundary condition equations can be solved analytically in fairly simple forms. Applying the same methodology to cased and cemented boreholes, however, is much more difficult because of the increased number of simultaneous boundary condition equations. I circumvent this difficulty by solving the boundary condition equations numerically using propagator matrices, as is generally done in the calculation of synthetic full‐waveform acoustic logs. In this way, the assumption of low frequency is also avoided, and a generalized stationary‐phase solution for sources in general, concentrically layered borehole models is easily obtained. Computation of the radiation patterns for cased and uncased boreholes in various formations shows that the amplitude reduction, because of the introduction of casing, is a function of both source type and of formation velocities. Axial stress sources are less affected by the casing than either radial stress or volume‐injection sources, and as formation velocity decreases, the effect of the casing becomes more significant as the impedance contrast between steel and the formation becomes larger. The new generalized stationary‐phase solution also shows that as frequency approaches 1000 Hz, the results obtained by low‐frequency approximations for stress sources can be inaccurate and that the energy radiated from the source becomes more highly directed in the horizontal directions. The radiation pattern begins to change relatively rapidly as a function of frequency, so that the resulting observations from broad‐band sources will show changes in waveforms that mimic the effects of attenuation. These changes occur because the length of the source becomes important as wavelength decreases, demonstrating the need to consider the influence of frequency, as well as casing and cement, on source radiation.
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Sabater, Neus, Jorge Vicent, Luis Alonso, Jochem Verrelst, Elizabeth Middleton, Albert Porcar-Castell, and José Moreno. "Compensation of Oxygen Transmittance Effects for Proximal Sensing Retrieval of Canopy–Leaving Sun–Induced Chlorophyll Fluorescence." Remote Sensing 10, no. 10 (September 26, 2018): 1551. http://dx.doi.org/10.3390/rs10101551.
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Estimates of Sun–Induced vegetation chlorophyll Fluorescence (SIF) using remote sensing techniques are commonly determined by exploiting solar and/or telluric absorption features. When SIF is retrieved in the strong oxygen (O 2 ) absorption features, atmospheric effects must always be compensated. Whereas correction of atmospheric effects is a standard airborne or satellite data processing step, there is no consensus regarding whether it is required for SIF proximal–sensing measurements nor what is the best strategy to be followed. Thus, by using simulated data, this work provides a comprehensive analysis about how atmospheric effects impact SIF estimations on proximal sensing, regarding: (1) the sensor height above the vegetated canopy; (2) the SIF retrieval technique used, e.g., Fraunhofer Line Discriminator (FLD) family or Spectral Fitting Methods (SFM); and (3) the instrument’s spectral resolution. We demonstrate that for proximal–sensing scenarios compensating for atmospheric effects by simply introducing the O 2 transmittance function into the FLD or SFM formulations improves SIF estimations. However, these simplistic corrections still lead to inaccurate SIF estimations due to the multiplication of spectrally convolved atmospheric transfer functions with absorption features. Consequently, a more rigorous oxygen compensation strategy is proposed and assessed by following a classic airborne atmospheric correction scheme adapted to proximal sensing. This approach allows compensating for the O 2 absorption effects and, at the same time, convolving the high spectral resolution data according to the corresponding Instrumental Spectral Response Function (ISRF) through the use of an atmospheric radiative transfer model. Finally, due to the key role of O 2 absorption on the evaluated proximal–sensing SIF retrieval strategies, its dependency on surface pressure (p) and air temperature (T) was also assessed. As an example, we combined simulated spectral data with p and T measurements obtained for a one–year period in the Hyytiälä Forestry Field Station in Finland. Of importance hereby is that seasonal dynamics in terms of T and p, if not appropriately considered as part of the retrieval strategy, can result in erroneous SIF seasonal trends that mimic those of known dynamics for temperature–dependent physiological responses of vegetation.
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Elmets, Craig A., and Nabiha Yusuf. "Murine Skin Carcinogenesis and the Role of Immune System Dysregulation in the Tumorigenicity of 2-Ethylhexyl Acrylate." Biomedicine Hub 5, no. 2 (September 2, 2020): 1–16. http://dx.doi.org/10.1159/000508295.
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Some chemicals act as human carcinogens in various organ systems including the skin. Mice have been an ideal model to study a wide variety of chemical carcinogens because the pathogenesis in that species often mirrors that in humans. However, different mouse strains vary in their susceptibility to these agents. Thus, reliance on a single strain may lead to inaccurate findings. 2-Ethylhexyl acrylate (2-EHA) is an acrylate used as a co-monomer in the production of polymer resins for adhesives, latex paints, cross-linking agents, finishes for textiles and leather, and paper coatings. Monomer exposure may occur in occupational settings where it is produced or used; the only exposure that may occur to consumers or construction personnel is trace amounts in the final polymer product. There are no reports of cancer in humans caused by exposure to 2-EHA. However, 2-EHA has been reported to cause cancer in one strain of mice. This is an important issue since recommendations about its safety in humans depend, in part, on information derived from animal studies. We reviewed the literature on the preclinical effects of acrylates on skin carcinogenesis in C3H/HeJ mice, which can be criticized because of peculiarities in the immunological composition of that strain, the lack of rigorous histopathologic characterization of tumors that developed, the high doses of 2-EHA that were used for evaluation, and the lack of reproducibility in a second strain of mice. The C3H/HeJ mouse model is not ideal as it has a mutation in Toll-like receptor 4 (TLR4) that impairs its innate and adaptive immune responses. Inconsistencies in the histological evaluation of tumors induced in C3H/HeJ mice provide further evidence that the tumorigenic effect of 2-EHA was strain specific, a result of chronic inflammation during the promotion stage and/or a skewed immune response caused by the TLR4 mutation. In conclusion, 2-EHA has not convincingly been demonstrated to have skin carcinogenic activity to date. More relevant mouse models that mimic human squamous cell carcinoma, basal cell carcinoma, and melanoma with amounts that do not exceed a maximum tolerated dose are needed to assess the carcinogenic effects of 2-EHA.
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Loegering, Julia, Kevin Webb, Jesse Ahlquist, Kevin Krause, Karen Xu, David G. Greenhalgh, Tina L. Palmieri, and Nam K. Tran. "511 Point-of-care 3-dimensional Body Mapping for Determining Total Body Surface Area in Severely Burned Patients." Journal of Burn Care & Research 41, Supplement_1 (March 2020): S92—S93. http://dx.doi.org/10.1093/jbcr/iraa024.143.
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Abstract Introduction With severe burn injury, there is systemic fluid loss due to inflammatory responses in damaged tissue, leading to disruption of cellular processes. Patient fluid levels are restored with the calculation of total body surface area (TBSA). Clinically used TBSA equations are often outdated and inaccurate with error up to 20%, resulting in misinformed treatment and subsequent sequelae including prolonged hospital length of stay and increased mortality. Our objective, therefore, was to create a point-of-care (POC) system employing 3D imaging technology to accurately calculate TBSA for all patient population varieties. Methods Our team employed an iPad attachable, infrared scanner to create 3D models of the human body. From these models, TBSA can be extrapolated using scan processing software. Subject scans were collected on our device and on a gold standard scanner for comparison of TBSA output. Clinical testing on burn patients is occurring at present to establish scanning precision of TBSA in the burn care environment. Results Non-clinical verification tests of the 3D scanned TBSA revealed a 4.05% error when compared to the gold standard, and precision error of 3.8%. Additionally, we introduced the device into the burn unit for preliminary testing with a physician user and non-patient subjects. The subjects were scanned in a prone position to mimic burn care workflow. Clinician scanning error was 1.41% when compared to the gold standard scan of the same subject. Clinical precision study results are on-going in collection. Conclusions Our device introduces an improved method of TBSA estimation to assist clinicians in making accurate burn care decisions and further precision medicine with greater anthropomteric data, notably for children. This device is one of the first POC-3D scanning technologies to be used in a burn setting and may also be employed at outlying medical facilities. Destructive wildfires and combat burn injuries highlight the need for such a device to standardize the triage of burn victims with and away from experienced medical staff. Applicability of Research to Practice 3D body mapping points to an enhanced method of TBSA calculation and minimally disruptive to the burn workflow. Future developments of 3D scanning include deep learning algorithms to identify and better assess burned surface area. Additionally, further automation of TBSA scan processing to reduce user error in calculation and improve burn injury outcomes.
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Bernard, Olivier, Olivier Alata, and Marc Francaux. "On the modeling of breath-by-breath oxygen uptake kinetics at the onset of high-intensity exercises: simulated annealing vs. GRG2 method." Journal of Applied Physiology 100, no. 3 (March 2006): 1049–58. http://dx.doi.org/10.1152/japplphysiol.00712.2005.
Full textAbstract:
Modeling in the time domain, the non-steady-state O2 uptake on-kinetics of high-intensity exercises with empirical models is commonly performed with gradient-descent-based methods. However, these procedures may impair the confidence of the parameter estimation when the modeling functions are not continuously differentiable and when the estimation corresponds to an ill-posed problem. To cope with these problems, an implementation of simulated annealing (SA) methods was compared with the GRG2 algorithm (a gradient-descent method known for its robustness). Forty simulated V̇o2 on-responses were generated to mimic the real time course for transitions from light- to high-intensity exercises, with a signal-to-noise ratio equal to 20 dB. They were modeled twice with a discontinuous double-exponential function using both estimation methods. GRG2 significantly biased two estimated kinetic parameters of the first exponential (the time delay td1 and the time constant τ1) and impaired the precision (i.e., standard deviation) of the baseline A0, td1, and τ1 compared with SA. SA significantly improved the precision of the three parameters of the second exponential (the asymptotic increment A2, the time delay td2, and the time constant τ2). Nevertheless, td2 was significantly biased by both procedures, and the large confidence intervals of the whole second component parameters limit their interpretation. To compare both algorithms on experimental data, 26 subjects each performed two transitions from 80 W to 80% maximal O2 uptake on a cycle ergometer and O2 uptake was measured breath by breath. More than 88% of the kinetic parameter estimations done with the SA algorithm produced the lowest residual sum of squares between the experimental data points and the model. Repeatability coefficients were better with GRG2 for A1 although better with SA for A2 and τ2. Our results demonstrate that the implementation of SA improves significantly the estimation of most of these kinetic parameters, but a large inaccuracy remains in estimating the parameter values of the second exponential.
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Labuschagne, Jason, John Frean, Kaajal Parbhoo, Denis Mutyaba, Tanyia Pillay, Shareen Boughan, and Hlezikuhle Nkala. "Disseminated Human Subarachnoid Coenurosis." Tropical Medicine and Infectious Disease 7, no. 12 (November 29, 2022): 405. http://dx.doi.org/10.3390/tropicalmed7120405.
Full textAbstract:
Background: Traditionally, human coenurosis has been ascribed to Taenia multiceps while neurocysticercosis has been attributed solely to Taenia solium infection. Historically, however, the identification and differentiation of cestodal infection was primarily based on inaccurate morphological criteria. With the increasing availability of molecular methods, the accuracy of identification of the larval cestode species has improved, and cestodal species not typically associated with central nervous system (CNS) infection are now being identified as aetiological agents. Case report: We present a case of a 5-year-old male patient who presented with acute hydrocephalus. Initial MRI revealed multiple cysts in the cerebrospinal fluid (CSF) spaces with a predominance of clumped grape-like cysts in the basal cisterns with resultant acute obstructive hydrocephalus. The child underwent an emergency ventriculo-peritoneal (VP) shunt. A presumptive diagnosis of neurocysticercosis racemosus was made and the child was started on empiric albendazole (15 mg/kg/day) and praziquantel (30 mg/kg/day) treatment, along with concomitant prednisone (1 mg/kg) treatment. Despite prolonged anti-helminthic therapy, the child continued to deteriorate, and endoscopic removal of the 4th ventricular cysts was required. Post-operative MRI revealed radiological improvements, with a reduction in the number and size of cysts, especially in the basal cisterns, with no cysts visualized in the fourth ventricle. DNA was extracted from CSF and cyst tissue using the QiAMP DNA mini kit (Qiagen). The PCR performed on the extracted DNA displayed a band of 275 bp on an agarose gel. The consensus sequence had 97.68% similarity to Taenia serialis 12S ribosomal RNA gene. The child, unfortunately, continued to do poorly, requiring multiple VP shunt revisions for repeated blockage of the VP shunt system, and ultimately demised, despite the ‘successful’ surgical intervention and continued maximal medical management. Discussion and conclusions: There have been approximately 40 reported cases of human CNS coenurosis, with the assumed etiological agent being confined to T. multiceps. In 2020, the first case of human CNS coenurosis caused by T. serialis was reported. This case involved a single parenchymal lesion in the occipital lobe, which, following complete surgical excision, was confirmed to be T. serialis by mitochondrial gene sequencing. The case we present is the first case of disseminated subarachnoid coenurosis caused by T. serialis. It appears that T. serialis infection can mimic either of the two basic pathological forms of neurocysticercosis, namely, cysticercosis cellulosae or cysticercosis racemosus. We postulate that the term coenurosis racemosus is applicable if CNS T. serialis infection presents with extensive, multiple grape-like bladders proliferating within the subarachnoid space.
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Jafari Daghlian Sofla, Saeed, Lesley Anne James, and Yahui Zhang. "Toward a mechanistic understanding of wettability alteration in reservoir rocks using silica nanoparticles." E3S Web of Conferences 89 (2019): 03004. http://dx.doi.org/10.1051/e3sconf/20198903004.
Full textAbstract:
Traditional concepts of simple liquid spreading may not apply to nanoparticle-fluids. Most investigations pertaining to the wettability alteration of solid surfaces due to the presence of nanoparticles in the fluid are oversimplified, i.e. nanoparticles dispersed in DI-water and smooth, homogeneous, and clean surfaces have been used. From a practical enhanced oil recovery (EOR) point of view, the nanoparticles must be dispersed in either seawater or high salinity formation water containing diverse types and concentrations of ions. These ions interact with the electrostatic properties of the nanoparticles. Likewise, the oil phase may contain many surface active components like asphaltene and naphthenic acids which can interact with nanoparticles at oil-water and oil-rock interface. In reality, the rock sample is a heterogeneous, non-smooth, mixed-wet substrate with a diverse mineralogical composition. The electrical charge of minerals can vary when contacted with an ionic fluid. This can alter the electrostatic repulsion between substrate and nanoparticles and consequently the substrate can either attract or repel charged particles, including nanoparticles. Hence, the role of nanoparticles must be evaluated considering multicomponent complex fluids and real formation rock. Despite numerous reports regarding the wettability alteration of reservoir rock from oil-wet to water-wet by nanoparticles, some inherent limitations in the wettability alteration experiments prevent conclusions about the performance of nanoparticles in practical complex conditions. For instance, the wettability alteration by nanoparticles is often determined by contact angle measurements. In this method, the substrates are either aged with (immersed in) nanoparticle-fluids before conducting the experiments or contacted with nanoparticle-fluids before attachment of the oil droplet on the rock surface. Hence, in both cases, before initiating the contact angle measurements, the nanoparticles would already exist at the oil-rock interface possibly giving inaccurate measurements. The objective of this work is to investigate the mechanism of wettability alteration by silica nanoparticles pre-existing on the rock interface (conventional contact angle measurements) and using a new displacement contact angle method to better mimic the scenario of injecting a nanoparticle fluid into the reservoir already containing formation brine. The impact of pre-existing nanoparticles at the oil-rock interface (in the conventional contact angle measurements) on the contact angle measurements are examined for simple (n-decane, NaCl brine, and pure substrates) and complex (crude oil, seawater, and reservoir rock) systems on various wetting conditions of substrates (water-wet and oil-wet). The nanoparticles are dispersed in seawater using our H+ protected method [1]. Then, the effect of surface and nanoparticle charge on the contact angle is evaluated by adjusting the aqueous phase salinity. We also differentiate between the disjoining pressure mechanism and diffusion of silica nanoparticles through the oil phase by testing the attachment of nanoparticles on the rock surface.
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Savedra, Michelle E., Jessica L. Szuberski, Tavanna R. Porter, Molly S. Hein, Phuong L. Nguyen, Min Shi, Aruna Rangan, James D. Hoyer, and Jennifer L. Oliveira. "Effects of Voxelotor (GBT440) Therapy on Laboratory Testing of Sickle Cell Patients." Blood 134, Supplement_1 (November 13, 2019): 1011. http://dx.doi.org/10.1182/blood-2019-131125.
Full textAbstract:
Background: Voxelotor (GBT440) is a small molecule allosteric effector with high specificity for hemoglobin (Hb) that inhibits Hb S polymerization by increasing hemoglobin oxygen affinity. Developed as an oral, once-daily medication, it is undergoing phase 3 randomized clinical trials in sickle cell disease patients. Therapeutic monitoring of Hb quantitative fractions is routine in sickle cell disease patients to assess medication and transfusion effects and future treatment requirements. In the clinical laboratory, some therapies can alter the Hb fraction percentages or characteristic protein migration/elution patterns and can mimic complex hemoglobinopathy disorders causing misinterpretation or unnecessary additional testing. We present the effects of voxelotor on hemoglobin identification/monitoring testing in multiple testing platforms. Methods: A whole blood anticoagulated sample from a male patient who was undergoing treatment for sickle cell disease was received for routine hemoglobin testing. Five additional samples with similar features were also received from three male patients (age range of all patients was 18 to 22 years) with sickle cell disease. Hemoglobin protein analysis was performed using standard methods including cation-exchange high performance liquid chromatography (HPLC), capillary electrophoresis (CE), isoelectric focusing (IEF), intact globin chain mass spectrometry (MS), sickle solubility and hemoglobin stability studies. DNA sequencing of the alpha (HBA1/HBA2) and beta globin (HBB) genes was performed on one sample. Results: CE (initial and 50:50 mix, figures 1A and 1B, respectively) revealed a Hb S peak with a shoulder and additional small peaks at position 203 (D zone) and 234 (cusp of zones E/A2). In some cases the 234 peak interfered with instrument designation of the A2 peak (50:50 mix with normal) and shifted the Hb S peak into the E zone which risks variant misidentification (figure 1C). Our laboratory overcame this limitation by substituting the normal sample with beta thalassemia trait to enhance the Hb A2 peak after mixing. HPLC tracings (figure 1D) showed a duplex peak pattern in the D and S windows with separate peak quantification percentages (index case showed elution at 4.18 and 4.37 minutes with 14.9% and 66.4%, respectively). The dual peaks detected by HPLC partially mimicked compound Hb S/D-Punjab. IEF (figure 1E) showed additional bands at -4.7, and -11.5 (Schneider-Barwick ratios). The additional peaks identified by CE and IEF mimicked an alpha chain hemoglobin variant; however, the expected hybrid patterns were atypical prompting further investigation. Sickle solubility was positive, heat stability studies were negative and mass spectrometry did not definitively detect abnormal peaks other than βS. DNA sequencing of the alpha and beta globin genes did not reveal abnormalities other than homozygous Hb S. Similar hemoglobin patterns were identified in all samples tested. Conclusion: Voxelotor treatment in sickle cell patients results in a distinctive pattern alteration in hemoglobin testing. Methods may not give accurate variant percentage estimation and the treatment may result in shifts in variant mobility causing erroneous laboratory results. Novel therapies are increasing in the treatment of hemoglobin disorders and medication effect should be a consideration when atypical patterns are encountered in the laboratory. Knowledge of these artifacts by clinicians and laboratorians is paramount to avoid erroneous diagnosis, unnecessary additional testing and inaccurate Hb variant quantitation for monitoring purposes. Notification of current treatment regimens to testing facilities is highly recommended in these patients. Figure 1 Disclosures No relevant conflicts of interest to declare.