Littérature scientifique sur le sujet « Precise framework alteration »
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Articles de revues sur le sujet "Precise framework alteration"
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Alghanim, Firas, Ibrahim Al-Hurani, Hazem Qattous, Abdullah Al-Refai, Osamah Batiha, Abedalrhman Alkhateeb et Salama Ikki. « Machine Learning Model for Multiomics Biomarkers Identification for Menopause Status in Breast Cancer ». Algorithms 17, no 1 (28 décembre 2023) : 13. http://dx.doi.org/10.3390/a17010013.
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Identifying menopause-related breast cancer biomarkers is crucial for enhancing diagnosis, prognosis, and personalized treatment at that stage of the patient’s life. In this paper, we present a comprehensive framework for extracting multiomics biomarkers specifically related to breast cancer incidence before and after menopause. Our approach integrates DNA methylation, gene expression, and copy number alteration data using a systematic pipeline encompassing data preprocessing and handling class imbalance, dimensionality reduction, and classification. The framework starts with MutSigCV for data preprocessing and ensuring data quality. The Synthetic Minority Over-sampling Technique (SMOTE) up-sampling technique is applied to address the class imbalance representation. Then, Principal Component Analysis (PCA) transforms the DNA methylation, gene expression, and copy number alteration data into a latent space. The purpose is to discard irrelevant variations and extract relevant information. Finally, a classification model is built based on the transformed multiomics data into a unified representation. The framework contributes to understanding the complex interplay between menopause and breast cancer, thereby revealing more precise diagnostic and therapeutic strategies in the future. The explainable artificial intelligence model Shapley based on the XGBoost regressor showed the power of the selected gene expressions for predicting the menopause status, and the potential biomarkers included RUNX1, PTEN, MAP3K1, and CDH1. The literature confirmed the findings.
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Michael Owenvbiugie Eguagie, Idoko Peter Idoko, Onuh Matthew Ijiga, Lawrence Anebi Enyejo, Francisca Chinonye Okafor et Chinelo Nwaamaka Onwusi. « Geochemical and Mineralogical Characteristics of Deep Porphyry Systems : Implications for Exploration Using ASTER ». International Journal of Scientific Research in Civil Engineering 9, no 1 (4 janvier 2025) : 01–21. https://doi.org/10.32628/ijsrce25911.
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Porphyry systems are critical sources of economically valuable metals, making their identification and exploration a key focus in mineral resource studies. Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) data have emerged as a powerful tool for mapping the geochemical and mineralogical characteristics of these systems, enabling more precise exploration efforts. This review examines the geochemical and mineralogical indicators of deep porphyry systems and evaluates the effectiveness of ASTER in their exploration. It begins by exploring the geological framework and alteration zones typical of porphyry deposits, emphasizing the unique advantages of ASTER in remote sensing applications. The methodology focuses on evaluating case studies where ASTER data were utilized to map alteration minerals and detect geochemical anomalies, alongside techniques for data processing and ground-truth validation. Results reveal that ASTER effectively identifies critical alteration zones and mineralogical features, though challenges remain in distinguishing overlapping mineral signatures in complex terrains. Recommendations include integrating ASTER with complementary geophysical and geochemical methods and advancing data processing techniques to enhance exploration accuracy. This study highlights ASTER’s significant potential in driving efficient and sustainable exploration of deep porphyry systems.
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Hai, Nguyen Ngoc, Nguyen Nguyen Chuong, Nguyen Huu Cam Tu, Anna Kisiala, Xuan Lan Thi Hoang et Nguyen Phuong Thao. « Role and Regulation of Cytokinins in Plant Response to Drought Stress ». Plants 9, no 4 (31 mars 2020) : 422. http://dx.doi.org/10.3390/plants9040422.
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Cytokinins (CKs) are key phytohormones that not only regulate plant growth and development but also mediate plant tolerance to drought stress. Recent advances in genome-wide association studies coupled with in planta characterization have opened new avenues to investigate the drought-responsive expression of CK metabolic and signaling genes, as well as their functions in plant adaptation to drought. Under water deficit, CK signaling has evolved as an inter-cellular communication network which is essential to crosstalk with other types of phytohormones and their regulating pathways in mediating plant stress response. In this review, we revise the current understanding of CK involvement in drought stress tolerance. Particularly, a genetic framework for CK signaling and CK crosstalk with abscisic acid (ABA) in the precise monitoring of drought responses is proposed. In addition, the potential of endogenous CK alteration in crops towards developing drought-tolerant crops is also discussed.
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Proudfoot, L., J. R. Kusel, H. V. Smith et M. W. Kennedy. « External stimuli and intracellular signalling in the modification of the nematode surface during transition to the mammalian host environment ». Parasitology 107, no 5 (décembre 1993) : 559–66. http://dx.doi.org/10.1017/s0031182000068141.
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SUMMARYPrevious work has shown that the surface of infective larvae of parasitic nematodes will not bind the fluorescent lipid analogue 5-N(octadecanoyl)aminofluorescein (AF18) until after exposure of the parasite to mammalian tissue-culture conditions. In this study, culture media which are permissive or non-permissive for the acquisition of lipophilicity for AF18 were altered in order to examine possible stimuli involved. This showed that external alkaline pH and high sodium ion concentration were highly stimulatory. The internal signalling pathways which may be involved in the surface alteration were then examined using agents which are known to affect intracellular signalling in mammalian cells. The results indicated that elevation of cGMP levels was stimulatory whereas inhibition of a putative Na+/H+ antiporter or calcium mobilization was inhibitory, and it is argued that high intracellular levels of cAMP may be inhibitory. Whilst the precise effects of the agents used on nematode cells remain to be established, these results provide a framework for the examination of the processes involved in the modification of the nematode surface which takes place immediately after the infection event.
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Shapshay, Stanley M., Zhi Wang, Donald F. Perrault, Elie E. Rebeiz et Michail M. Pankratov. « “Window” Laryngoplasty : A New Combined Laser Endoscopic and Open Technique for Conservation Surgery ». Annals of Otology, Rhinology & ; Laryngology 103, no 9 (septembre 1994) : 679–85. http://dx.doi.org/10.1177/000348949410300904.
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Endoscopic laser resection of early laryngeal carcinoma is an increasingly used treatment modality; however, the limited exposure achieved and the alteration of vocal function are still major problems. A new surgical procedure, “window” laryngoplasty, has been devised and tested in an in vivo study in 6 canines with 50 days' survival. The right vocal cord was incised endoscopically with the carbon dioxide laser, and the en bloc specimen with adjacent thyroid cartilage was removed through a window approach made in the thyroid cartilage. A sternohyoid muscle flap based superiorly was inserted into the cartilaginous window to reconstruct a pseudocord with coverage of either mucosa or fascia. A diode laser soldering technique was used to secure the mucosal graft in place. Epithelial transplantation can be accomplished externally with precise endoscopic guidance for reliable placement of the pseudocord. The results show that the new technique, a combination of endoscopic and open approaches, may be a better treatment choice than standard vertical partial laryngectomy in selected patients. Advantages of this technique include adequate en bloc resection, including adjacent cartilage for pathologic evaluation, preservation of the integrity of most of the laryngeal framework, avoidance of tracheotomy, and better functional results.
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VOLDMAN, GUSTAVO G., JUAN L. ALONSO, LUIS P. FERNÁNDEZ, ALDO L. BANCHIG, GUILLERMO L. ALBANESI, GLADYS ORTEGA et RAÚL CARDÓ. « Cambrian–Ordovician conodonts from slump deposits of the Argentine Precordillera : new insights into its passive margin development ». Geological Magazine 155, no 1 (18 octobre 2016) : 85–97. http://dx.doi.org/10.1017/s0016756816000832.
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AbstractThe Los Sombreros Formation represents the western continental margin slope deposits of the Argentine Precordillera, a sub-terrane accreted to Gondwana as part of the Cuyania Terrane in early Palaeozoic times. The age of these gravity-driven deposits is controversial and, therefore, a precise biostratigraphic scheme is essential to reveal the evolution of the continental margin. New conodont samplings along with sedimentological and structural analysis carried out in the Los Sombreros Formation in the La Invernada Range provide clues to its depositional framework. The sedimentary succession is made up of dominantly calciturbidites, carbonate breccias and conglomerates, along with mudstones that represent the pelagic/hemipelagic background sedimentation. It displays hectometric to outcrop-scale slump folds with variable hinge-line orientations and pinch-and-swell structures, evidencing soft-sediment deformation, consistent with a slope to base-of-slope setting. Three limestone samples from this succession include conodonts referable to the pandemicHirsutodontus simplexSubzone of theCordylodus intermediusZone (upper Furongian, Cambrian) and from theMacerodus dianaeZone (upper Tremadocian, Ordovician), implying that a slope connected the shallow-water shelf with a deep-water (oceanic) basin at least since late Cambrian times. The conodont faunas show affinities to coeval assemblages from outer shelf and slope environments around Laurentia yet they are not conclusive to postulate a geographic origin for the Precordillera. The thermal alteration of the conodonts is consistent with sedimentary burial and nappe stacking in this sector of the Precordillera.
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Weber, Remi, Flavio Vasella, Artsiom Klimko, Manuela Silginer, Martine L. M. Lamfers, Luca Regli, Gerald Schwank et Michael Weller. « EXTH-37. TARGETING THE IDH1R132H MUTATION IN GLIOMAS BY CRISPR-CAS PRECISION BASE EDITING ». Neuro-Oncology 24, Supplement_7 (1 novembre 2022) : vii217. http://dx.doi.org/10.1093/neuonc/noac209.835.
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Abstract Gliomas are the most frequent malignant primary brain tumors and continue to lack curative therapies. To aid the development of novel therapeutic approaches, a better understanding of glioma-specific molecular patterns is essential. We therefore investigate the role of the canonical point mutation in the isocitrate dehydrogenase 1 gene (IDH1R132H). Its early occurrence in oncogenesis and ubiquitous expression suggests a causative driver function; however, current literature is inconclusive on the impact of IDH1R132H, requiring innovative approaches to further elucidate the functional consequences and therapeutic potential of IDH1R132H. METHODS Clustered, regularly interspaced, short palindromic repeat (CRISPR)-Cas precision base editing systems enable the alteration of a specific base pair without suffering from off-target editing associated with previous, double strand brake-inducing systems and thus making them an ideal tool to revert the point mutation in IDH1R132H gliomas. RESULTS By selecting a CRISPR-Cas precision base editing system, the IDH1R132H site was edited with editing efficiencies of up to 50%. Primary patient derived cell lines and organoids were corrected in their IDH1R132H locus. Phenotypical changes, such as a change in IDH1R132H protein levels, 2-hydroxyglutarate concentration as well as proliferation rates were observed upon the reversal of the point mutation. Furthermore, the precision base editing system was packaged into a dual-AAV-vector split intein system and showed successful in vitro gene editing. In conclusion, this precise genetic intervention provides a methodology to create accurate patient derived models to analyze the impact of IDH1R132H on glioma biology and provides a framework for in vivo gene therapy.
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Adamczyk, Mikołaj, Piotr Parasiewicz, Paolo Vezza, Paweł Prus et Giovanni De Cesare. « Empirical Validation of MesoHABSIM Models Developed with Different Habitat Suitability Criteria for Bullhead Cottus Gobio L. as an Indicator Species ». Water 11, no 4 (8 avril 2019) : 726. http://dx.doi.org/10.3390/w11040726.
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Application of instream habitat models such as the Mesohabitat Simulation Model (MesoHABSIM) is becoming increasingly popular. Such models can predict alteration to a river physical habitat caused by hydropower operation or river training. They are a tool for water management planning, especially in terms of requirements of the Water Framework Directive. Therefore, model verification studies, which investigate the accuracy and reliability of the results generated, are essential. An electrofishing survey was conducted in September 2014 on the Stura di Demonte River located in north-western Italy. One hundred and sixteen bullhead—Cottus gobio L.—were captured in 80 pre-exposed area electrofishing (PAE) grids. Observations of bullhead distribution in various habitats were used to validate MesoHABSIM model predictions created with inductive and deductive habitat suitability indices. The inductive statistical models used electrofishing data obtained from multiple mountainous streams, analyzed with logistic regression. The deductive approach was based on conditional habitat suitability criteria (CHSC) derived from expert knowledge and information gathered from the literature about species behaviour and habitat use. The results of model comparison and validation show that although the inductive models are more precise and reflect site- and species-specific characteristics, the CHSC model provides quite similar results. We propose to use inductive models for detailed planning of measures that could potentially impair riverine ecosystems at a local scale, since the CHSC model provides general information about habitat suitability and use of such models is advised in pre-development or generic scale studies. However, the CHSC model can be further calibrated with localized electrofishing data at a lower cost than development of an inductive model.
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Meiliana, Anna, Nurrani Mustika Dewi et Andi Wijaya. « Mitochondrial Dysfunction in Stem Cell Aging ». Indonesian Biomedical Journal 7, no 1 (1 avril 2015) : 15. http://dx.doi.org/10.18585/inabj.v7i1.18.
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BACKGROUND: Regardless of the precise underlying molecular mechanisms, the fundamental defining manifestation of aging is an overall decline in the functional capacity of various organs to maintain baseline tissue homeostasis and to respond adequately to physiological needs under stress. There is an increasingly urgent need for a more complete understanding of the molecular pathways and biological processes underlying aging and age-related disorders.CONTENT: Mitochondria constitute the most prominent source of adenosine triphosphate (ATP) and are implicated in multiple anabolic and catabolic circuitries. In addition, mitochondria coordinate cell-wide stress responses and control non-apoptotic cell death routines. The involvement of mitochondria in both vital and lethal processes is crucial for both embryonic and postembryonic development, as well as for the maintenance of adult tissue homeostasis. Age-associated telomere damage, diminution of telomere ‘capping’ function and associated p53 activation have emerged as prime instigators of a functional decline of tissue stem cells and of mitochondrial dysfunction that adversely affect renewal and bioenergetic support in diverse tissues. Constructing a model of how telomeres, stem cells and mitochondria interact with key molecules governing genome integrity, ‘stemness’ and metabolism provides a framework for how diverse factors contribute to aging and age-related disorders.SUMMARY: Cellular senescence defined as an irreversible proliferation arrest promotes age-related decline in mammalian tissue homeostasis. The aging of tissue-specific stem cell and progenitor cell compartments is believed to be central to the decline of tissue and organ integrity and function in the elderly. Taken into consideration that the overwhelming majority of intracellular reactive oxygen species (ROS) are of mitochondrial origin, it is reasonable to posit that the elevated ROS production might be caused by alteration in mitochondrial function during senescence. It is likely that mitochondria and stem cells will remain at the forefront of aging research also for the next decade.KEYWORDS: aging, stem cell, mitochondrial biogenesis, mitophagy, senescence, telomeres
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Raimondi, D., A. V. Martynenko, L. Barsi, N. Marchitto et L. V. Maliarova. « Biofeedback of elderly patients with chronic pain : new nonlinear Heart Rate Variability analysis ». Journal of V. N. Karazin Kharkiv National University, Series "Medicine", no 49 (28 juin 2024) : 161–71. http://dx.doi.org/10.26565/2313-6693-2024-49-04.
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Background. Chronic pain presents a substantial clinical challenge affecting individuals across all age groups, regardless of whether they are adults or older adults. To underscore the impact of biofeedback in managing chronic pain, we conducted a statistical analysis to explore its short-term effectiveness and factors influencing treatment outcomes. Purpose – to develop the advanced heart rate variability (HRV) methods that reflect a statistically significant relationship between the impact of biofeedback on chronic pain control and HRV indicators that outline changes in the influence of the sympathetic and parasympathetic systems in pain regulation. Materials and Methods. Elderly patients with mean age 76.3 ± 7.5 years suffering from Chronic Pain associated with Chronic Skeletal Illness. Prior to treatment and after a 15-day period, all participants underwent assessment of pain severity. Additionally, each participant underwent a 5-minute EKG recording before and after treatment to evaluate Heart Rate Variability (HRV). Neuro-vegetative cardiovascular modulation was assessed through EKG analysis of HRV before and after treatment. Biofeedback sessions (5 breaths per minute) were conducted twice daily for 5 minutes over the course of 15 days. For the purpose of this research data analysis, we propose a novel Heart Rate Variability (HRV) methodology incorporating robust entropy estimation and fuzzy logic algorithms. The robust entropy estimation algorithm enables precise computation of entropy values from time series data of limited length, while the fuzzy logic algorithm facilitates integration of various HRV metrics (including time domain, frequency domain, and nonlinear methods) into a unified framework. Results. Through the utilization of this proposed methodology, we assess the therapeutic efficacy of biofeedback and the involvement of the neuro-vegetative cardiovascular system in chronic pain. Conclusions. Our preliminary findings reveal a statistically significant reduction in pain severity, as measured by the Visual Analog Scale (VAS), without a statistically significant alteration in neuro-vegetative cardiovascular modulation using conventional analysis techniques. However, the application of the new HRV methodology incorporating robust entropy estimation and fuzzy logic algorithms enables the detection of significant variations.
Thèses sur le sujet "Precise framework alteration"
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Li, Xinghan. « Catalytic strategies designed for precise framework alteration : navigating the uncharted chemical space for drug discovery ». Electronic Thesis or Diss., Strasbourg, 2025. http://www.theses.fr/2025STRAF001.
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Nous avons introduit deux stratégies programmables pour obtenir des modifications précises squelette moléculaire de produits naturels complexes—une synthèse de base progressivement divergente et un stratagème d'édition à un stade avancé. Le développement d'un processus catalytique est au cœur de la première stratégie. Grâce à un réseau progressivement divergent, nous avons synthétisé un alcaloïde rare et ses analogues squelettiques. Le pivot de la seconde stratégie est la métathèse des oléfines (OM), y compris l'éthénolyse, la métathèse croisée et la métathèse de fermeture de cycle qui sont catalysées par divers complexes de Ru, W et Mo. La MO et d'autres réactions clés nous ont permis de synthétiser une série d'analogues squelettiques de l'épothilone. Les tests in vitro, les études de « docking » et la dynamique moléculaire valident notre approche et soulignent qu'un remodelage précis du cadre peut conduire à des pistes non naturelles intéressantesWe introduced two programmable strategies to achieve precise skeletal alterations on complex natural products—a progressively divergent ground-up synthesis scheme and a late-stage editing stratagem. Central to the former is the development of a catalytic enantioselective multicomponent process affording a primary hub, transformation of which by a progressively divergent network delivered a scarce alkaloid and its precision skeletal analogs. The linchpin of the latter strategy is the tactical use of olefin metathesis (OM) reactions, including ethenolysis, cross-metathesis, and ring-closing metathesis that are catalyzed by various Ru-, W-, and Mo-complexes. The confluence of OM and other key reactions led us to synthesize an array of skeletally altered epothilone C analogs. In vitro testing, docking, and molecular dynamics validate our approach and justify our contention that precise framework remodeling can lead to the identification of exciting non-natural leads
Chapitres de livres sur le sujet "Precise framework alteration"
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Ni, Jing, Qiulei Yao, Yanfei Liu et Haikun Qi. « A Coarse-to-Fine Framework for Mid-Radiotherapy Head and Neck Cancer MRI Segmentation ». Dans Lecture Notes in Computer Science, 154–65. Cham : Springer Nature Switzerland, 2025. https://doi.org/10.1007/978-3-031-83274-1_11.
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Abstract Radiotherapy is the preferred treatment modality for head and neck cancer (HNC). During the treatment, adaptive radiation therapy (ART) technology is commonly employed to account for changes in target volume and alterations in patient anatomy. This adaptability ensures that treatment remains precise and effective despite these physiological variations. Magnetic resonance imaging (MRI) provides higher-resolution soft tissue images, making it valuable in target delineation of HNC treatment. The delineation in ART should adhere to the same principles as those used in the initial delineation. Consequently, the contouring performed on MR images during ART should reference the earlier delineations for consistency and accuracy. To address this, we proposed a coarse-to-fine cascade framework based on 3D U-Net to segment mid-radiotherapy HNC from T2-weighted MRI. The model consists of two interconnected components: a coarse segmentation network and a fine segmentation network, both sharing the same architecture. In the coarse segmentation phase, different forms of prior information were used as input, including dilated pre-radiotherapy masks. In the fine segmentation phase, a resampling operation based on a bounding box focuses on the region of interest, refining the prediction with the mid-radiotherapy image to achieve the final segmentation. In our experiment, the final results were achieved with an aggregated Dice Similarity Coefficient (DSC) of 0.562, indicating that the prior information plays a crucial role in enhancing segmentation accuracy. (Team name: TNL_skd)
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Kovač, Nataša, Špiro Ivošević et Gyöngyi Vastag. « Statistical Methods Applied in Modeling Corrosion Depth Measurement on Three Different Shape Memory Alloys ». Dans Corrosion Engineering - Recent Breakthroughs and Innovative Solutions [Working Title]. IntechOpen, 2024. http://dx.doi.org/10.5772/intechopen.1005179.
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This chapter presents a study focused on the corrosion behavior of three distinct shape memory alloys (CuAlNi and two types of NiTi alloys) in varied marine environments—air, tide, and seawater. The research documents corrosion damage after 6, 12, and 18 months, utilizing focused ion beam. Scanning electron microscopy and energy dispersive X-ray analyses were employed to detect the chemical alterations. This study includes both deterministic and stochastic frameworks for modeling corrosion processes. Employing a range of statistical techniques, including linear and multivariate regression, principal component analysis, and correlation analysis (linking corrosion depth with oxygen presence), the research provides an in-depth understanding of corrosion dynamics. The study explores fitting standard two-parameter and advanced multi-parameter distributions to the observed data. The dual treatment of corrosion parameters via linear and non-linear models enhances the robustness and applicability of our findings, offering more precise and effective corrosion management in marine engineering applications.
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Vogt, Brent A., Leslie J. Vogt, Dushyant P. Purohit et Patrick R. Hof. « Cingulate Subregional Neuropathology in Dementia with Lewy Bodies and Parkinson’s Disease with Dementia ». Dans Cingulate Neurobiology and Disease, 707–26. Oxford University PressOxford, 2009. http://dx.doi.org/10.1093/oso/9780198566960.003.0032.
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Abstract The Lewy body (LB) is one of the most common markers of cingulate neuropathology; exceeded only by amyloid-β peptides. Disorders in which LBs are encountered in the cingulate gyrus include Alzheimer’s disease (AD), Parkinson’s disease with dementia (PDD), dementia with Lewy bodies (DLB), and aging (Saito et al., 2003). Cases with LBs form 15–25% of all cases of dementia which is second only to that of pure AD (McKeith et al., 1996); however, as LBs are observed in more than half of definite AD cases, they are common in AD (Ditter & Mirra, 1987). The comorbid expression of DLB and AD is still a matter of debate because key markers of both diseases are so frequently observed in the same cases (Perl et al., 1998). Moreover, in addition to ‘pure’ forms of each of these progressive dementing diseases, their conjunction throughout the cingulate gyrus generates a complex neuropathological context in which to consider symptom etiology that still has not been resolved.The Consensus Guidelines for DLB identified progressive mental impairment leading to dementia as the central feature of DLB (McKeith et al., 1996). They also concluded that attentional impairments, visual hallucinations, and spontaneous motor features of Parkinsonism are essential diagnostic features for discriminating DLB from AD and other dementias. Although visual hallucinations may result from alterations in occipital lobe functions and progressive mental impairment results from general cortical damage, some of these symptoms do not result from primary cortical damage and little is known of how impairment of specific cingulate functions contribute to the early and progressive symptoms of DLB. A new generation of functional imaging research provides a more precise framework in which to evaluate structure/function correlates in progressive dementing disorders.
Actes de conférences sur le sujet "Precise framework alteration"
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Nousir, S., et J. Kalucki. « How Does Precise Control Affect the Outcome of Nitriding and Ferritic Nitrocarburizing Cycles ? » Dans HT2019. ASM International, 2019. http://dx.doi.org/10.31399/asm.cp.ht2019p0166.
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Abstract Controlled nitriding and ferritic nitrocarburizing cycles have become commonly used to improve wear resistance, mechanical properties, and corrosion resistance. The framework for process control is based on standards such as AMS 2759/10 and 2759/12A. In all cases, these standards allow for a tolerance in control parameters. This work presents the influence of standard allowed deviations in control parameters, for example, nitriding potential and temperature for a given furnace class, on actual results when comparing iron, carbon steel and low alloy steel samples. The results point to interesting variations in white layer thickness. We also discuss other potential factors such as the shift of actual results due to carbon and alloying elements, and the subsequent alteration of results between expected and actual as demonstrated by shifting boundaries on the Lehrer diagram. As a conclusion, the study underlines the fact that while tolerances are allowed, precise control in specific furnace classes is necessary to obtain an ideal repetition of results. Additionally, improved control lowers gas usage and gas flows to a strict minimum, with a direct impact on the cost of quality, cost of treatment, and emissions affecting the environment.
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Matsuoka, Yuki, Mamoru Kikumoto, Sho Ogata et Kiyoshi Kishida. « Incorporating Roughness Degradation Within the Critical State Framework : Modeling the Shear Behavior of Rock Joints ». Dans 58th U.S. Rock Mechanics/Geomechanics Symposium. ARMA, 2024. http://dx.doi.org/10.56952/arma-2024-0733.
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ABSTRACT: Rock masses are characterized by numerous structural discontinuities, such as joints and faults, which exert a significant influence on their deformation responses. Therefore, it is important to develop a constitutive model that can accurately anticipate the mechanical response of rock joints. A previous study proposed an elastoplastic constitutive model based on the critical state framework originally developed in soil mechanics. The fundamental assumption of this model is that a rock joint reaches a critical state, where the shear stress and aperture is uniquely determined relative to the applied normal stress, after a large shear displacement. This model accounts for the joint matching by evaluating the difference in joint aperture between the current and the critical state. However, its applicability to rock joints remains incomplete, particularly in accommodating the influence of roughness degradation. Roughness degradation on joint surfaces can lead to a reduction in the asperity angle, resulting in a decrease in aperture at the critical state and a dilatancy response. In this study, we extend the aforementioned model by introducing a state parameter to account for the changes in critical state aperture. The proposed model effectively captures alterations in the shear response associated with the roughness degradation, providing a more comprehensive understanding of the mechanical behavior of rock joints. 1. INTRODUCTION The precise anticipation of rock mass behavior is critical in designing and maintaining rock structures such as tunnels, dam foundations, geological repositories for radioactive waste, and energy storage facilities. Within the rock mass, numerous discontinuities, such as faults and joints, characterized by reduced stiffness and strength compared to the rock materials, exert a significant influence on the overall rock mass behavior. In addition, alterations in stress conditions within the rock mass resulting from subsurface activities can induce slippage of these discontinuities, precipitating the failure or collapse of the entire rock mass. Therefore, comprehending and managing the slip behavior of discontinuities, particularly those surrounding underground structures, represents one of the critical challenges in rock engineering. Although various studies have explored slip/shear behavior, the surface roughness (Barton, 1973) and interlocking (Zhao, 1997a) of rock joints are important factors influencing shear behavior under applied stress conditions common in rock engineering. Numerous numerical methodologies have been proposed to forecast the behavior of discontinuities in rock. Nevertheless, enhancing constitutive models to incorporate geological characteristics of in-situ joints remain imperative.
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Karimli, J., T. Yeleskina, A. Shafiyev, H. Asgarov, R. Malikov, O. Mammadov et I. Shahsenov. « Estimation of Gamma Ray Values with Deep Learning from Seismic ». Dans SPE Caspian Technical Conference and Exhibition. SPE, 2023. http://dx.doi.org/10.2118/217566-ms.
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Abstract Seismic inversion is pivotal in the oil and gas industry, aiding geophysicists in understanding reservoir characteristics. Despite its widespread use, the limitations of seismic data, like low resolution, introduce uncertainties that impede direct application. This study introduces an innovative method to estimate 3D Gamma Ray data from seismic reflectivity, reshaping reservoir understanding and management. The study's goal was to predict 3D Gamma Ray data and its uncertainty via seismic reflectivity. This was achieved by employing Functional Convolutional Neural Networks (FCNNs) and Continuous Wavelet Transform. By merging well data and seismic information using signal processing and deep learning, accurate forecasts of Gamma Ray values were accomplished. It's worth noting that this manuscript constitutes as a continuation of the scientific research project initiated by Shahsenov et al. in 2022. The authors describe the updated methodology, the improvements achieved in the results, as well as any alterations made to the methodological framework. The quality of prediction was validated through several statistical techniques, ensuring robustness. Blind wells were thoughtfully integrated into various analyses to facilitate a comparison between actual and predicted log values. The outcomes of these evaluations, promising in nature and showcasing notable advancements over the earlier work, are represented visually and in detail through the report. In summary, this research pioneers a seismic inversion shift and builds upon prior research (Shahsenov et al., 2022). The combination of seismic reflectivity and deep learning allows precise prediction of 3D Gamma Ray values. By combining well and seismic data, the challenge of sparse logs is addressed, empowering geophysicists for more effective reservoir management. This enhanced reservoir understanding promotes data-driven decisions in the oil and gas sector.