bluuebunny/crossref_metadata_2025_split huggingface dataset:
Surfactant and a Mixture of Surfactant and Nanoparticles Stabilized-CO2/Brine Foam for Gas Mobility Control and Enhance Oil Recovery
Authors: AlYousef Zuhair , Almobarky Mohammed , Schechter David 
Published: August 2017

Abstract
Injecting carbon dioxide (CO2) into oil reservoirs has the potential to enhance oil recovery (EOR) and mitigate climate change by storing CO2 underground. Despite successes in using CO2 to enhance oil recovery, mobility control remains a major challenge facing CO2 injection projects. The objective of this work is to investigate the potential of using surfactant and a mixture of surfactant and nanoparticles (NPs) to generate foam to reduce gas mobility and enhanced oil recovery.
A newly developed anionic surfactant and a mixture of the surfactant and surface modified silica NPs were used to assess the ability of generating a stable foam at harsh reservoir conditions: sc-CO2 and high temperature. Dynamic foam tests and coreflood experiments were conducted to evaluate foam stability and strength. To measure the mobility of injected fluids in sandstone rocks, the foam was generated by co-injection of sc-CO2 and surfactant, as well as a mixture of surfactant and NPs at 90% quality. The coreflood experiments were conducted using non-fractured and fractured sandstone cores at 1550 psi and 50°C.
Surfactant alone and mixtures of surfactant and NPs were able to generate foam in porous media and reduce CO2 mobility. The mobility reduction factor (MRF) for both cases was about 3.5 times higher than that of injecting CO2 and brine at the same conditions. The coreflood experiments in non-fractured sandstone rocks showed that both surfactant and a mixture of surfactant and NPs were able to enhance oil recovery. The baseline experiment in the absence of surfactant resulted in a total recovery of 71.50% of the original oil in place (OOIP). Using surfactant brought the oil recovery to 76% of the OOIP. The addition of NPs to surfactant resulted in a higher oil recovery still, 80% of the OOIP. In fractured rocks, oil recoveries during secondary production mechanisms for the mixture, the surfactant alone, and sc-CO2 alone were 12.62, 8.41 and 7.21% of the OOIP, respectively.
CO2-EOR in Fractured Ultra-Low Permeability Reservoirs: Problems and Remedial Measures
Authors: Liu Xiaochun , Ma Liping , Tan Junling , Yang Tangying , Li Xiaorong , Hou Jirui , Wei Qi , Hao Hongda , Song Zhaojie , Wang Shitou , Bi Weiyu 
Published: August 2017

Abstract
H-3 Block is an ultra-low permeability reservoir in Changqing oil field, China which had been waterflooded from 2009 and was switched to CO2 flooding in 2013 due to excess water production. However, the nature fractures in NE-SW region have resulted in early CO2 breakthrough and poor production performance. The investigation of CO2 production performance and the method to control CO2 production becomes a key to continue CO2-EOR project.
Outcrop cores are used to perform a series of CO2 flooding experiments at reservoir conditions of pressure, temperature and formation water salinity. Permeability heterogeneity and injection pressure are considered as two variables to affect gas channeling characteristics. It is figured out that producing gas-oil ratio and components analysis of effluent could be used to judge gas channeling and timing to control CO2 production for field use. Starch gel is developed to control CO2 production within nature fractures to improve CO2 swept volume in rock matrix. Ethylenediamine (EDA) is proposed to delay CO2 production within high-permeability zones, and the application boundary as a function of permeability heterogeneity is determined.
Three production stages are clearly stated based on production performance and experimental observation, including gas-free production stage, oil/gas co-production stage, and gas channeling stage. A significant new finding is that oil/gas co-production stage contributes the most to oil recovery. And oil-CO2 mass transfer zone, rather than free CO2, reaches the outlet at this stage, which is proved by color of effluent and chromatographic analysis. For field cases, producing gas-oil ratio and components analysis of effluent at wellhead could help field engineers make a decision: keep producing with caution at oil-gas co-production stage or control the CO2 production at gas channeling stage. The conformance improvement and the increase in injection pressure could remarkably enhance the oil recovery at oil/gas co-production stage. To delay gas channeling and extent oil/gas co-production stage, two-level gas channeling control is presented. A slug of starch gel is first injected to block fractures and then ethylenediamine is injected to react with in-situ CO2 within high-permeability zone. The starch gel, acting as pure viscous fluid, would not leave contamination in rock matrix. And the viscous reactant of ethylenediamine and in-situ CO2 could successfully tune injected CO2 to flood low-permeability zone when permeability ratio is less than 100.
Gouvernance des régimes complémentaires de retraite, relations du travail et conflits de rôle : une enquête québécoise
Authors: Coulombe Daniel , Déom Esther , Hanin Frédéric , Hayden Annette 
Published: August 2017

Cette recherche vise à étudier la présence de conflits de rôle au sein des comités de retraite au Québec. Elle met en relation la gouvernance des régimes de retraite et la présence de conflits de rôle entre la représentation collective et la responsabilité fiduciaire du point de vue des membres de comités de retraite. Nous exploitons une particularité de la gestion québécoise, soit l’obligation de créer un comité de retraite sur lequel siègent des membres représentant l’employeur, les syndicats, les travailleurs, les retraités, ainsi que des membres indépendants. À l’aide d’une méthodologie mixte par questionnaire et par entrevue, il a été possible d’analyser les sources et la nature des conflits.
Contrairement à nos anticipations, notre étude ne démontre pas de conflits systématiques causés par la coexistence du système de relations du travail et de la responsabilité fiduciaire des régimes complémentaires de retraite. Les tensions reliées aux relations du travail sont minimes. Nous avons bien identifié quelques enjeux, notamment au niveau du financement des régimes, de la viabilité des régimes, qui relèvent de la confusion des rôles.
Toutefois ces éléments ne sont pas perçus comme des sources de tensions, mais plutôt comme des enjeux à discuter. La qualité de la gouvernance des régimes de retraite dépend des ressources investies par les acteurs des relations du travail dans l’accompagnement des membres des comités de retraite. La recherche sur les conflits de rôle dans la gouvernance des régimes de retraite au Québec montre que la gestion de ces conflits dépend, dans une large mesure, de la qualité de la législation sur l’administration des régimes complémentaires de retraite au Québec et, également, des ressources consacrées à la formation des membres des comités de retraite et des participants aux relations du travail.
FDA Perspective on the Regulation of Artificial Intelligence in Health Care and Biomedicine
Authors: Warraich Haider J. , Tazbaz Troy , Califf Robert M. 
Published: October 2024

ImportanceAdvances in artificial intelligence (AI) must be matched by efforts to better understand and evaluate how AI performs across health care and biomedicine as well as develop appropriate regulatory frameworks. This Special Communication reviews the history of the US Food and Drug Administration’s (FDA) regulation of AI; presents potential uses of AI in medical product development, clinical research, and clinical care; and presents concepts that merit consideration as the regulatory system adapts to AI’s unique challenges.ObservationsThe FDA has authorized almost 1000 AI-enabled medical devices and has received hundreds of regulatory submissions for drugs that used AI in their discovery and development. Health AI regulation needs to be coordinated across all regulated industries, the US government, and with international organizations. Regulators will need to advance flexible mechanisms to keep up with the pace of change in AI across biomedicine and health care. Sponsors need to be transparent about and regulators need proficiency in evaluating the use of AI in premarket development. A life cycle management approach incorporating recurrent local postmarket performance monitoring should be central to health AI development. Special mechanisms to evaluate large language models and their uses are needed. Approaches are necessary to balance the needs of the entire spectrum of health ecosystem interests, from large firms to start-ups. The evaluation and regulatory system will need to focus on patient health outcomes to balance the use of AI for financial optimization for developers, payers, and health systems.Conclusions and RelevanceStrong oversight by the FDA protects the long-term success of industries by focusing on evaluation to advance regulated technologies that improve health. The FDA will continue to play a central role in ensuring safe, effective, and trustworthy AI tools to improve the lives of patients and clinicians alike. However, all involved entities will need to attend to AI with the rigor this transformative technology merits.
Application of Community Detection Methods to Identify Emergency General Surgery–Specific Regional Networks
Authors: Han Jiuying , Wan Neng , Horns Joshua J. , McCrum Marta L. 
Published: October 2024

ImportanceThere is growing interest in developing coordinated regional systems for nontraumatic surgical emergencies; however, our understanding of existing emergency general surgery (EGS) care communities is limited.ObjectiveTo apply network analysis methods to delineate EGS care regions and compare the performance of this method with the Dartmouth Health Referral Regions (HRRs).Design, Setting, and ParticipantsThis cross-sectional study was conducted using the 2019 California and New York state emergency department and inpatient databases. Eligible participants included all adult patients with a nonelective admission for common EGS conditions. Interhospital transfers (IHTs) were identified by transfer indicators or temporally adjacent hospitalizations at 2 different facilities. Data analysis was conducted from January to May 2024.ExposureAdmission for primary EGS diagnosis.Main Outcomes and MeasuresRegional EGS networks (RENs) were delineated by modularity optimization (MO), a community detection method, and compared with the plurality-based Dartmouth HRRs. Geographic boundaries were compared through visualization of patient flows and associated health care regions. Spatial accuracy of the 2 methods was compared using 6 common network analysis measures: localization index (LI), market share index (MSI), net patient flow, connectivity, compactness, and modularity.ResultsA total of 1 244 868 participants (median [IQR] age, 55 [37-70 years]; 776 725 male [62.40%]) were admitted with a primary EGS diagnosis. In New York, there were 405 493 EGS encounters with 3212 IHTs (0.79%), and 9 RENs were detected using MO compared with 10 Dartmouth HRRs. In California, there were 839 375 encounters with 10 037 IHTs (1.20%), and 14 RENs were detected compared with 24 HRRs. The greatest discrepancy between REN and HRR boundaries was in rural regions where one REN often encompassed multiple HRRs. The MO method was significantly better than HRRs in identifying care networks that accurately captured patients living within the geographic region as indicated by the LI and MSI for New York (mean [SD] LI, 0.86 [1.00] for REN vs 0.74 [1.00] for HRR; mean [SD] MSI, 0.16 [0.13] for REN vs 0.32 [0.21] for HRR) and California (mean [SD] LI, 0.83 [1.00] for REN vs 0.74 [1.00] for HRR; mean [SD] MSI, 0.19 [0.14] for REN vs 0.39 [0.43] for HRR). Nearly 27% of New York hospitals (37 of 139 hospitals [26.62%]) and 15% of California hospitals (48 of 336 hospitals [14.29%]) were reclassified into a different community with the MO method.Conclusions and RelevanceDevelopment of optimal health delivery systems for EGS patients will require knowledge of care patterns specific to this population. The findings of this cross-sectional study suggest that network science methods, such as MO, offer opportunities to identify empirical EGS care regions that outperform HRRs and can be applied in the development of coordinated regional systems of care.
Replacing manual planning with automatic iterative planning for locally advanced rectal cancer VMAT treatment
Authors: Liu Jiacheng , Wang Ruoxi , Wang Qingying , Yao Kaining , Wang Meijiao , Du Yi , Yue Haizhen , Wu Hao 
Published: October 2024

AbstractPurposeTo develop and implement a fully automatic iterative planning (AIP) system in the clinical practice, generating volumetric‐modulated arc therapy plans combined with simultaneous integrated boost technique VMAT (SIB‐VMAT) for locally advanced rectal cancer (LARC) patients.MethodThe designed AIP system aimed to automate the entire planning process through a web‐based service, including auxiliary structure generation, plan creation, field configuration, plan optimization, dose calculation, and plan assessment. The system was implemented based on the Eclipse scripting application programming interface and an efficient iterative optimization algorithm was proposed to reduce the required iterations in the optimization process. To verify the performance of the implemented AIP system, we retrospectively selected a total of 106 patients and performed dosimetric comparisons between the automatic plans (APs) and the manual plans (MPs), in terms of dose‐volume histogram (DVH) metrics, homogeneity index (HI), and conformity index (CI) for different volumes of interest.ResultThe AIP system has successfully created 106 APs within clinically acceptable timeframes. The average planning time per case was 36.8 ± 6.5 min, with an average iteration number of 6.8 (±1.1) in plan optimization. Compared to MPs, APs exhibited better performance in the planning target volume conformity and hotspot control (). The organs at risk (OARs) sparing was significantly improved in APs, with mean dose reductions in the femoral heads, the bone marrow, and the SmallBowel‐Avoid of 0.53 Gy, 1.18 Gy, and 1.00 Gy, respectively (). Slight improvement was also observed in the urinary bladder and the small bowel . Additionally, quality variation between plans from different planners was observed in DVH metrics while the APs represented better plan quality consistency.ConclusionAn AIP system has been implemented and integrated into the clinical treatment planning workflow. The AIP‐generated SIB‐VMAT plans for LARC have demonstrated superior plan quality and consistency compared with the manual counterparts. In the meantime, the planning time has been reduced by the AIP approach. Based on the reported results, the implemented AIP framework has been proven to improve plan quality and planning efficiency, liberating planners from the laborious parameter‐tuning in the optimization phase.
Fixed‐Time State Observer‐Based Robust Adaptive Neural Fault‐Tolerant Control for a Quadrotor Unmanned Aerial Vehicle
Authors: Ranjan Sanjeev , Majhi Somanath 
Published: October 2024

ABSTRACTThis paper presents a fixed‐time state observer‐based robust adaptive neural fault‐tolerant control (RANFTC) for attitude and altitude tracking and control of quadrotor unmanned aerial vehicles (UAVs), considering multiple actuator faults, parametric uncertainty, and unknown external disturbances simultaneously. A novel fixed‐time state error estimation based on sliding mode observer is designed, which is independent of initial conditions. A proportional–integral–derivative (PID) based sliding mode control (SMC) is proposed to handle actuator faults and unknown disturbances in combination with the fixed‐time observer within the fault‐tolerant control (FTC) design scheme. The radial basis function neural network (RBFNN) is employed with the controller to approximate the uncertain parameters of the system. Furthermore, two new adaptive laws are designed to estimate the sudden actuator fault and the unknown upper bound of disturbances independently. Implementing these estimation schemes avoids overestimation, enhances the robustness of the presented controller, and substantially eliminates the control chattering problem. By applying the Lyapunov stability concept, the suggested control strategy guarantees that the states of the quadrotor UAV converge to the origin in a finite time. Finally, simulation studies are conducted to demonstrate the tracking performance and highlight the effectiveness of the proposed FTC design compared to the existing FTC methods.
Electroacupuncture Slows Experimental Myopia Progression by Improving Retinal Mitochondrial Function: A Study Based on Single‐Cell RNA Sequencing
Authors: Hao Jiawen , Xie Yunxiao , Wei Huixia , Yang Zhaohui , Zhang Ruixue , Ma Zhongyu , Zhang Miao , Du Xiaoshi , Yin Xuewei , Liu Jinpeng , Bao Bo , Bi Hongsheng , Guo Dadong 
Published: October 2024

AbstractThis study aimed to establish a complete atlas of retinal cells in lens‐induced myopia (LIM) and electroacupuncture (EA) intervention by single‐cell RNA sequencing (scRNA‐seq) and to explore the potential mechanism of EA in improving experimental myopia progression in guinea pigs. scRNA‐seq is used to assess changes in individual cellular gene levels in the retina of LIM‐ and EA‐treated guinea pigs. In addition, the role of EA in slowing myopia progression by improving retinal mitochondrial function is further investigated. scRNA‐seq identified ten cell clusters in the retina of LIM and EA guinea pigs and mitochondrial respiratory chain‐related genes in Cones and Muller‐glia cells—Cytochrome oxidase subunit III (COX3), NADH dehydrogenase subunit 4 (ND4), and NADH dehydrogenase subunit 2 (ND2) are closely related to lens‐induced myopia. A comprehensive atlas in the retina of LIM and EA guinea pigs at a single‐cell level is established, and the positive role of EA in improving retinal mitochondrial function to slow the experimental myopia progression in guinea pigs is revealed.
Surface Defects‐Induced Photoactivation of Carbon Dots‐NiFe2O4 Nanocomposite: Synthesis, Mechanism and Applications
Authors: Xie Ruyan , Zhang Shuzhe , Song Yanhua , Zhang Xiaozhen , Sheng Shihou , Zou Haifeng 
Published: October 2024

AbstractThe optical properties of quantum dots are significantly influenced by photoactivation. However, the progress in the development of photoactivation carbon dot (CDs) is still stagnant. Herein, a method for preparing photoactivated CDs/NiFe2O4 by introducing affluent defects onto the surface of CDs through modification with NiFe2O4, extremely filling the gap of photoactivated CDs is proposed. Interestingly, a fantastic fluorescence detection strategy in a unique “OFF‐ON‐OFF” mode, combined with Ag+‐assisted fluorescence enhancement, to establish a dual‐channel regulation mechanism for ultra‐sensitive detection of Hg2+ is first proposed. By increasing surface traps and non‐radiative recombination, defect‐induced manipulation on the surface of CDs creates favorable conditions for enhancing photoactivation capacity. Unexpectedly, the CDs/NiFe2O4 shows a 25‐fold enhancement in fluorescence intensity after exposure to UV‐lamp. Compared to CDs/NiFe2O4, Ag+‐assisted photoactivation CDs/NiFe2O4 exhibits superior selectivity and sensitivity for Hg2+ detection, with low detection limits of 0.7 nM. Moreover, TiO2@CDs/NiFe2O4 catalyst is successfully prepared by anchoring CDs/NiFe2O4 onto the surface of TiO2, which demonstrates efficient degradation of tetracycline within 90 min under visible light irradiation, with a degradation rate of 98.3%. This work first provides a novel defects modification strategy for developing highly active photoactivated CDs technology that is significant for future environmentally sensitive applications.
Self‐Powered Iontronic Capacitive Sensing Unit with High Sensitivity in Charge‐Output Mode
Authors: Liu Jianxing , Liu Haiyang , Guo Haoyu , Huang Linwei , Lu Tongqing 
Published: October 2024

AbstractThe operation of iontronic capacitive sensors typically requires an external alternating current (AC) power source, resulting in additional energy consumption and AC‐frequency‐related sensing performance. Here, a class of self‐powered iontronic capacitive sensing units (SICSUs) is proposed based on a dynamic electric double layer (EDL), with a significant charge sensitivity of up to 24270 pC N−1, surpassing most piezoelectric materials by nearly 10 times. The effects of various design parameters and loading conditions on the sensing performance of the SICSUs are systematically investigated. The EDL at the hydrogel‐electrode interface is characterized in situ, revealing the underlying mechanism for high sensitivity and linearity. The capability of SICSUs in detecting diverse human‐related mechanical loads is demonstrated. Furthermore, a robotic hand equipped with a SICSU‐based artificial algesia sensor is fabricated to mimic the withdrawal reflex behavior of a human hand when its skin detects noxious stimuli caused by sharp objects.
Photo‐Curable Fluorinated High‐k Polyimide Dielectrics by Polar Side Substitution Effect for Low‐Voltage Operating Flexible Printed Electronics
Authors: Ye Heqing , Kwon Hyeok‐jin , Kim Yejin , Park Su Bin , Wang Rixuan , Benliang Hou , Gwon Ji‐eun , Wu Kaibin , Wu Yizhang , Zhang Hongjian , Chang Dong Wook , Lim Bogyu , Lee Seung Woo , Kim Se Hyun 
Published: October 2024

AbstractPolyimide‐based dielectric films are widely used in various thin film devices including organic field‐effect transistors (OFETs) owing to their promising thermal/chemical stability, mechanical flexibility, and insulating properties. On the other hand, considerable attention is paid to lowering the process temperature to allow coating on plastic substrates because high‐temperature annealing (≈200 °C) is usually required to convert precursors to polyimide films with those excellent properties. In addition, polyimide‐based dielectric films have low dielectric constants (k) (<4). Therefore, modifying the k properties of polyimide is a critical issue for applications as an insulating thin film for practical transistors. This paper reports a new type of polyimide‐based gate dielectric comprising methacryloyl moiety (PI‐MA) as a side chain for photo‐pattern/processability and high‐k properties. This study shows that the photocured PI‐MA thin films show excellent insulating properties (leakage current densities < 10−8 A cm⁻2 at 4 MV cm⁻1) and high‐k properties (≈8) even without a post‐annealing process. Finally, the use of PI‐MA in printed field‐effect transistors results in high performance with low‐voltage operation (within 5 V) and integrated logic‐gate devices (NOT, NAND, and NOR gates).