Toward Reservoir-on-a-Chip: Rapid Performance Evaluation of Enhanced Oil Recovery Surfactants for Carbonate Reservoirs Using a Calcite-Coated Micromodel

AbstractEnhanced oil recovery (EOR) plays a significant role in improving oil production. Tertiary EOR, including surfactant flooding, can potentially mobilize residual oil after water flooding. Prior to the field deployment, the surfactant performance must be evaluated using site-specific crude oil at reservoir conditions. Core flood experiments are common practice to evaluate surfactants for oil displacement efficiency using core samples. Core flood experiments, however, are expensive and time-consuming and do not allow for pore scale observations of fluid-fluid interactions. This work introduces the framework to evaluate the performance of EOR surfactants via a Reservoir-on-a-Chip approach, which uses microfluidic devices to mimic the oil reservoir. A unique feature of this study is the use of chemically modified micromodels such that the pore surfaces are representative of carbonate reservoir rock. To represent calcium carbonate reservoir pores, the inner channels of glass microfluidic devices were coated with thin layers of calcium carbonate nanocrystals and the surface was modified to exhibit oil-wet conditions through a crude oil aging process. During surfactant screening, oil and water phases were imaged by fluorescence microscopy to reveal the micro to macro scale mechanisms controlling surfactant-assisted oil recovery. The role of the interfacial tension (IFT) and wettability in the microfluidic device was simulated using a phase-field model and compared to laboratory results. We demonstrated the effect of low IFT at the oil-water interface and wettability alteration on surfactant-enhanced oil displacement efficiency; thus providing a time-efficient and low-cost strategy for quantitative and qualitative assessment. In addition, this framework is an effective method for pre-screening EOR surfactants for use in carbonate reservoirs prior to further core and field scale testing.</jats:p

Hierarchically structured magnetic nanoconstructs with enhanced relaxivity and cooperative tumor accumulation

Iron oxide nanoparticles are formidable multifunctional systems capable of contrast enhancement in magnetic resonance imaging, guidance under remote fields, heat generation, and biodegradation. Yet, this potential is underutilized in that each function manifests at different nanoparticle sizes. Here, sub-micrometer discoidal magnetic nanoconstructs are realized by confining 5 nm ultra-small super-paramagnetic iron oxide nanoparticles (USPIOs) within two different mesoporous structures, made out of silicon and polymers. These nanoconstructs exhibit transversal relaxivities up to ≈10 times (r 2 ≈ 835 mm -1 s-1) higher than conventional USPIOs and, under external magnetic fields, collectively cooperate to amplify tumor accumulation. The boost in r 2 relaxivity arises from the formation of mesoscopic USPIO clusters within the porous matrix, inducing a local reduction in water molecule mobility as demonstrated via molecular dynamics simulations. The cooperative accumulation under static magnetic field derives from the large amount of iron that can be loaded per nanoconstuct (up to ≈65 fg) and the consequential generation of significant inter-particle magnetic dipole interactions. In tumor bearing mice, the silicon-based nanoconstructs provide MRI contrast enhancement at much smaller doses of iron (≈0.5 mg of Fe kg-1 animal) as compared to current practice. © 2014 WILEY-VCH Verlag GmbH &amp; Co. KGaA, Weinheim

Ankle-brachial index and ocular diseases in a Russian population

Abstract Background To assess potential associations between the ankle-brachial blood pressure index (ABI) and ocular disorders. Methods In the population-based cross-sectional Russian Ural Eye and Medical Study including 5,899 (80.5%) out of 7328 eligible participants aged 40+ years, the participants underwent a series of ocular and medical examinations including measurement of ABI. Results Blood pressure measurements of both arms and ankles were available for 3187 (54.0%) individuals. The mean ABI was 1.26 ± 0.19 (median:1.20; range: 0.61, 2.20). In multivariate analysis, a higher ABI was associated with younger age (P &lt; 0.001; non-standardized regression coefficient B: −0.001; 95% confidence interval (CI): −0.002, −0.001), female sex (P &lt; 0.001; B: 0.03; 95% CI: 0.02, 0.04), lower body mass index (P &lt; 0.001; B: −0.004; 95% CI: −0.006, −0.003), lower waist-to-hip ratio (P = 0.01; B: −0.10; 95% CI: −0.17, −0.02), lower glucose serum concentration (P = 0.008; B: −0.005; 95% CI: −0.009, −0.001), lower prevalence of arterial hypertension (P &lt; 0.001; B: −0.14; 95% CI: −0.16, −0.12), higher mean systolic blood pressure (P &lt; 0.001; B: 0.003; 95% CI: 0.002, 0.003), and higher prevalence of any alcohol consumption (P &lt; 0.001; B: 0.03; 95% CI: 0.02, 0.04). In that multivariate model, prevalence of glaucoma (P = 0.67) as a whole, open-angle glaucoma (P = 0.86) and angle-closure glaucoma (P = 0.54), stage of glaucomatous optic neuropathy (P = 0.57), prevalence of age-related macular degeneration (P = 0.88), prevalence and stage of diabetic retinopathy (P = 0.30, and P = 0.29, respectively), nuclear cataract (P = 0.32, and P = 0.41, resp.), cortical cataract (P = 0.33, and P = 0.92, resp.), subcapsular cataract (P = 0.74 and P = 0.60, resp.), and pseudoexfoliation (P = 0.44 and P = 0.47, resp.), intraocular pressure (P = 0.52), axial length (P = 0.20), and peripapillary retinal nerve fibre layer thickness (P = 0.55) were not significantly associated with the ABI. Conclusions In this ethnically mixed population from Russia, none of the major ocular diseases was associated with ABI suggesting that subclinical atherosclerosis is not markedly associated with the aetiology of these ocular disorders. </jats:sec

Axial length and its associations in the Ural Very Old Study

AbstractTo assess the distribution of axial length as surrogate for myopia and its determinants in an old population, we performed the Ural Very Old Study as a population-based cohort study. Out of 1882 eligible individuals aged 85 + years, the Ural Very Old Study performed in an urban and rural region in Bashkortostan/Russia included 1526 (81.1%) individuals undergoing ophthalmological and medical examinations with sonographic axial length measurement. Biometric data were available for 717 (47.0%) individuals with a mean age of 88.0 ± 2.6 years (range 85–98 years; 25%). Mean axial length was 23.1 ± 1.1 mm (range 19.37–28.89 mm). Prevalences of moderate myopia (axial length 24.5–&lt; 26.5 mm) and high myopia (axial length ≥ 26.5 mm) were 47/717 (6.6%; 95% CI 4.7, 8.4) and 10/717 (1.4%; 95% CI 0.5, 2.3), respectively. In multivariable analysis, longer axial length was associated (coefficient of determination r2 0.25) with taller body height (standardized regression coefficient beta:0.16;non-standardized regression coefficient B: 0.02; 95% confidence interval (CI) 0.01, 0.03; P &lt; 0.001), higher level of education (beta: 0.12; B: 0.07; 95% CI 0.02, 0.11; P = 0.002), and lower corneal refractive power (beta: − 0.35; B: − 0.23; 95% CI − 0.28, − 0.18; P &lt; 0.001). Higher prevalence of moderate myopia, however not of high myopia, was associated with higher educational level (OR 1.39; 95% CI 1.09, 1.68; P = 0.007) and lower corneal refractive power (OR 0.77; 95% CI 0.63, 0.94; P = 0.01). In this old study population, prevalence of moderate axial myopia (6.6% versus 9.7%) was lower than, and prevalence of high axial myopia (1.4% versus 1.4%) was similar as, in a corresponding study on a younger population from the same Russian region. Both myopia prevalence rates were higher than in rural Central India (1.5% and 0.4%, respectively). As in other, younger, populations, axial length and moderate myopia prevalence increased with higher educational level, while high myopia prevalence was independent of the educational level.</jats:p

Ankle-brachial index and ocular diseases in a Russian population

Background!#!To assess potential associations between the ankle-brachial blood pressure index (ABI) and ocular disorders.!##!Methods!#!In the population-based cross-sectional Russian Ural Eye and Medical Study including 5,899 (80.5%) out of 7328 eligible participants aged 40+ years, the participants underwent a series of ocular and medical examinations including measurement of ABI.!##!Results!#!Blood pressure measurements of both arms and ankles were available for 3187 (54.0%) individuals. The mean ABI was 1.26 ± 0.19 (median:1.20; range: 0.61, 2.20). In multivariate analysis, a higher ABI was associated with younger age (P &amp;lt; 0.001; non-standardized regression coefficient B: -0.001; 95% confidence interval (CI): -0.002, -0.001), female sex (P &amp;lt; 0.001; B: 0.03; 95% CI: 0.02, 0.04), lower body mass index (P &amp;lt; 0.001; B: -0.004; 95% CI: -0.006, -0.003), lower waist-to-hip ratio (P = 0.01; B: -0.10; 95% CI: -0.17, -0.02), lower glucose serum concentration (P = 0.008; B: -0.005; 95% CI: -0.009, -0.001), lower prevalence of arterial hypertension (P &amp;lt; 0.001; B: -0.14; 95% CI: -0.16, -0.12), higher mean systolic blood pressure (P &amp;lt; 0.001; B: 0.003; 95% CI: 0.002, 0.003), and higher prevalence of any alcohol consumption (P &amp;lt; 0.001; B: 0.03; 95% CI: 0.02, 0.04). In that multivariate model, prevalence of glaucoma (P = 0.67) as a whole, open-angle glaucoma (P = 0.86) and angle-closure glaucoma (P = 0.54), stage of glaucomatous optic neuropathy (P = 0.57), prevalence of age-related macular degeneration (P = 0.88), prevalence and stage of diabetic retinopathy (P = 0.30, and P = 0.29, respectively), nuclear cataract (P = 0.32, and P = 0.41, resp.), cortical cataract (P = 0.33, and P = 0.92, resp.), subcapsular cataract (P = 0.74 and P = 0.60, resp.), and pseudoexfoliation (P = 0.44 and P = 0.47, resp.), intraocular pressure (P = 0.52), axial length (P = 0.20), and peripapillary retinal nerve fibre layer thickness (P = 0.55) were not significantly associated with the ABI.!##!Conclusions!#!In this ethnically mixed population from Russia, none of the major ocular diseases was associated with ABI suggesting that subclinical atherosclerosis is not markedly associated with the aetiology of these ocular disorders

Concurrent vision and hearing impairment associated with cognitive dysfunction in a population aged 85+ years: the Ural Very Old Study

ObjectiveTo assess the prevalence of vision impairment, hearing impairment and dual sensory impairment (DSI) as combination of vision and hearing impairment, in association with cognitive dysfunction in a population aged 85+ years.MethodsThe cross-sectional population-based Ural Very Old Study, conducted in rural and urban Bashkortostan, Russia, between 2017 and 2020, included a detailed ocular and systemic examination with assessment of moderate to severe vision impairment (MSVI)/blindness (best-corrected visual acuity &lt;6/18), moderate to severe hearing loss (MSHL) and cognitive function.SettingA rural and urban area in Bashkortostan, Russia.ParticipantsOut of 1882 eligible individuals aged 85+ years, 1526 (81.1%) individuals participated.Primary and secondary outcome measuresPrevalence of vision, hearing and DSI and cognitive dysfunction.ResultsThe study included 731 (47.9%) individuals (mean age 88.1±2.7 years; median 87 years, range 85–98 years) with measurements of MSVI/blindness, MSHL and cognitive function. The prevalence of MSVI/blindness, MSHL, DSI and dementia were 51.8% (95% CI 48.2% to 55.5%), 33.1% (95% CI 29.7% to 36.5%), 20.5% (95% CI 17.8% to 23.5%) and 48.2% (95% CI 44.5% to 51.8%), respectively. Lower cognitive function score was associated with lower visual acuity (p&lt;0.001) and higher hearing loss score (p=0.03), after adjusting for older age (p=0.001), rural region of habitation (p=0.003), lower educational level (p&lt;0.001) and higher depression score (p&lt;0.001). Higher dementia prevalence was associated with higher MSHL prevalence (OR 2.18 95% CI 1.59 to 2.98; p&lt;0.001), higher MSVI/blindness prevalence (OR 2.09, 95% CI 1.55 to 2.81; p&lt;0.001) and higher DSI prevalence (OR 2.80, 95% CI 1.92 to 4.07; p&lt;0.001).ConclusionsIn this very old, multiethnic population from Russia, DSI (prevalence 20.5%), as compared with hearing impairment (OR 2.18) and vision impairment alone (OR 2.09), had a stronger association (OR 2.80) with dementia. The findings show the importance of hearing and vision impairment, in particular their combined occurrence, for dementia prevalence in an old population.</jats:sec