Construction of multi-mineral digital rocks for upscaling the numerical simulation of tight rock physical properties

Tight sandstone reservoirs are characterized by multi-scale pore space and high clay content, resulting in intricate rock physical responses. In this work, multi-scale imaging techniques, including computed tomography and stitched scanning electron microscopy, are applied to identify the large intergranular pores and micropores within major minerals. The pore structure of tight sandstones is quantitatively investigated using multi-scale images. Besides, multi-mineral digital rocks are constructed by performing registration and segmentation processing on the images obtained from microcomputed tomography and energy-dispersive scanning electron microscopy. These digital rocks are treated as composite materials consisting of different mineral types and micro-porosities, which enables the upscaling of the numerical simulation of rock physics properties. The results reveal that residual intergranular pores are interconnected through micropores within clay minerals, which significantly influences the electrical conductivities and permeabilities of tight sandstones. The proposed upscaling method can effectively couple the contribution of formation brine in multi-scale pores and clay minerals to bulk rock physics properties. This approach is suitable for the numerical simulation of diverse rock physical properties and can be applied to various tight reservoirs.Document Type: PerspectiveCited as: Hu, J., Xiao, Z., Ni, H., Liu, X. Construction of multi-mineral digital rocks for upscaling the numerical simulation of tight rock physical properties. Advances in Geo-Energy Research, 2023, 9(1): 68-70. https://doi.org/10.46690/ager.2023.07.0

Research on multi factor coupling accident triggering mechanism and accident risk control of gas pipeline leakage

In the domain of gas pipeline operations, significant safety hazards prevail. This study delves into the triggering mechanisms behind gas pipeline leakage incidents, pinpoints key risk factors contributing to these occurrences, and proposes effective control measures. By classifying risk coupling forms associated with various accidents, the N-K model formula is utilized to assess the coupling degree of primary risk factors. The resultant coupling relationship is integrated into the University of California at Irvine NETwork (UCINET), forming a complex network model for quantitative analysis. Secondary risk factors' coupling degrees are measured, and the network's characteristic parameters are scrutinized. Noteworthy risk factors within the network include improper maintenance (A3), unclear or missing signage (C4), equipment aging and wear (B10), unauthorized occupation of ground space (C5), failure to implement rules and regulations (D3), and failure of electrical protection (B5). By controlling the above risk factors, disrupting the coupling process of risk factors, and blocking the transmission pathways of risk factors, the objective is to prevent leakage incidents and ensure the safe operation of gas pipelines

Method for filling missing data of mine ventilation parameters

The intelligent mine ventilation system is very important for the intelligent construction of coal mines. In order to solve the problem of missing mine ventilation parameter data caused by the lack of measurement conditions, instrument signal interference, uneven wind speed of roadway section, improper manual operation and other restrictive factors during actual measurement of mine ventilation parameters, a method for filling the missing data of mine ventilation parameters based on the multiple imputation method of random forest-chained equation was proposed. Multiple imputation with chained equations is used to generate n filled values for each missing attribute value by iterations, resulting in n complete datasets, and a final complete dataset is obtained by analyzing and optimizing the n complete datasets. In order to improve the filling accuracy of missing values, the influence of the uncertainty of missing data of mine ventilation parameters on the analysis process is reasonably considered, and the missing data is filled in the prediction task of random forest in combination with the prediction mean matching model. Taking the Luxin No.2 Mine as an experimental example, the intelligent mine ventilation simulation system IMVS was used to preprocess the original data set of ventilation parameters of the Luxin No.2 Mine to obtain a complete and accurate complete dataset of mine ventilation parameters. Comparative experiments with different missing attributes, different data missing rates, and different number of iterations were conducted separately for the complete data set. The effectiveness of the model was evaluated by a variety of model evaluation indicators. The results show that the complete data set formed by the multiple imputation method of random forest-chained equation has good similarity with the original data set. Results of filling experiments with different missing columns show that the filling model can easily handle mixed data types, autonomously learning the correlations between parameters and thus reducing filling complexity. The n datasets formed after iterations are combined into a final dataset by analysis, which improves the filling accuracy. Experiments with different iterations on the complete data set after initial filling show that the data correlation will converge after a certain number of iterations

High Q-factor, high contrast, and multi-band optical sensor based on plasmonic square bracket dimer metasurface

A high-performance resonant metasurface is rather promising for diverse application areas such as optical sensing and filtering. Herein, a metal–insulator–metal (MIM) optical sensor with merits of a high quality-factor (Q-factor), multiple operating bands, and high spectrum contrast is proposed using plasmonic square bracket dimer metasurface. Due to the complex square bracket itself, a dimer structure of two oppositely placed square brackets, and metasurface array configuration, multiple kinds of mode coupling can be devised in the inner and outer elements within the metasurface, enabling four sensing channels with the sensitivities higher than 200 nm/RIU for refractive index sensing. Among them, the special sensing channel based on the reflection-type surface lattice resonance (SLR) mechanism has a full width at half maximum (FWHM) of only 2 nm, a high peak-to-dip signal contrast of 0.82, a high Q-factor of 548, and it can also behave as a good sensing channel for the thickness measurement of the deposition layer. The multi-band sensor can work normally in a large refractive index or thickness range, and the number of resonant channels can be further increased by simply breaking the structural symmetry or changing the polarization angle of incident light. Equipped with unique advantages, the suggested plasmonic metasurface has great potential in sensing, monitoring, filtering, and other applications

Cross-inhibition to heterologous foot-and-mouth disease virus infection induced by RNA interference targeting the conserved regions of viral genome

AbstractRNA interference (RNAi) is the process by which double-stranded RNA (dsRNA) directs sequence-specific degradation of messenger RNA in animal and plant cells. In mammalian cells, RNAi can be triggered by 21–23 nucleotide duplexes of small interfering RNA (siRNA). Strategies to inhibit RNA virus multiplication based on the use of siRNAs have to consider the high genetic polymorphism exhibited by this group of virus. Here we described a significant cross-inhibition of foot-and-mouth disease (FMD) virus (FMDV) replication in BHK-21 cells by siRNAs targeted to various conserved regions (5′NCR, VP4, VPg, POL, and 3′NCR) of the viral genome. The results showed that siRNAs generated in vitro by human recombinant dicer enzyme gave an inhibition of 10- to 1000-fold in virus yield of both homologous (HKN/2002) and heterologous (CHA/99) isolates of FMDV serotype O at 48 h post-infection (hpi). The inhibition extended to at least 6 days post-infection. For serotype Asia1, the virus yield in YNBS/58-infected cells examined at 12, 24, and 48 hpi decreased by ∼10-fold in cells pretreated with HKN/2002-specific siRNAs, but there was no significant decrease at 60 hpi. The inhibition was specific to FMDV replication, as no reduction was observed in virus yield of pseudorabies virus, an unrelated virus. Moreover, we also demonstrated an enhanced viral suppression could be achieved in BHK-21 cells with siRNA transfection after an infection had been established. These results suggested that siRNAs directed to several conserved regions of the FMDV genome could inhibit FMDV replication in a cross-resistance manner, providing a strategy candidate to treat high genetic variability of FMDV

Relationship Between Reactive Astrocytes, by [18F]SMBT-1 Imaging, with Amyloid-Beta, Tau, Glucose Metabolism, and TSPO in Mouse Models of Alzheimer’s Disease

Reactive astrocytes play an important role in the development of Alzheimer’s disease (AD). Here, we aimed to investigate the temporospatial relationships among monoamine oxidase-B, tau and amyloid-β (Aβ), translocator protein, and glucose metabolism by using multitracer imaging in AD transgenic mouse models. Positron emission tomography (PET) imaging with [18F]SMBT-1 (monoamine oxidase-B), [18F]florbetapir (Aβ), [18F]PM-PBB3 (tau), [18F]fluorodeoxyglucose (FDG), and [18F]DPA-714 (translocator protein) was carried out in 5- and 10-month-old APP/PS1, 11-month-old 3×Tg mice, and aged-matched wild-type mice. The brain regional referenced standard uptake value (SUVR) was computed with the cerebellum as the reference region. Immunofluorescence staining was performed on mouse brain tissue slices. [18F]SMBT-1 and [18F]florbetapir SUVRs were greater in the cortex and hippocampus of 10-month-old APP/PS1 mice than in those of 5-month-old APP/PS1 mice and wild-type mice. No significant difference in the regional [18F]FDG or [18F]DPA-714 SUVRs was observed in the brains of 5- or 10-month-old APP/PS1 mice or wild-type mice. No significant difference in the SUVRs of any tracer was observed between 11-month-old 3×Tg mice and age-matched wild-type mice. A positive correlation between the SUVRs of [18F]florbetapir and [18F]DPA-714 in the cortex and hippocampus was observed among the transgenic mice. Immunostaining validated the distribution of MAO-B and limited Aβ and tau pathology in 11-month-old 3×Tg mice; and Aβ deposits in brain tissue from 10-month-old APP/PS1 mice. In summary, these findings provide in vivo evidence that an increase in astrocyte [18F]SMBT-1 accompanies Aβ accumulation in APP/PS1 models of AD amyloidosis

Mechanisms by Which Physical Activity Modulates the Wnt/β-catenin Pathway to Alleviate Anxiety-like Depression

This study aimed to explore the effect of treadmill exercise on anxiety in rats. Thirty SPF male rats aged 2 months with a body mass of (225±25) g were randomly divided into control group (CG, n=10), chronic sleep deprivation group (CSD, n=10) and sleep deprivation exercise group (CSD+E, n=10) after adaptive feeding for 1 week. The CSD model of rats in CSD group and CSD+E group was made by multi platform water environment method. Sleep deprivation of 18 h per day (from 12:00 pm. to 6:00 am. the next day) for 8 weeks. The effect of running on the anxiety-like behaviour of CSD rats was examined in the open field test (OFT) and the elevated plus maze (EPM) experiment. Hematoxylin-eosin (HE) staining, Annexin V/PI flow cytometry, immunofluorescence staining, Western blot, RT-qPCR and other methods were used to detect the effects of treadmill exercise on the morphology of hippocampus, apoptosis related factors caspase-12, Bax, Bcl-1, inflammatory factors (IL-6, TNF-a), Wnt β- catenin, p- β-catenin. The results of HE staining showed that the brain tissue of the control rats was structurally intact, with thick layers of cone cells, relatively dense, neatly arranged and compact, the cell edge structures were intact and clearly visible, with no obvious abnormal changes. The cone cell layer of brain tissue in the chronic sleep deprivation group was thin, with relatively low cell density, disorganized and sparse arrangement, and blurred cell edges. The symptoms of the above pathological changes in brain tissue of rats in sleep deprivation exercise group gradually alleviated. OFT results showed that compared with CG group, the number of activities in the central region of CSD group was significantly reduced (P<0.01), and the total distance of exercise was significantly shortened (P<0.01). EPM results showed that compared with CG group, OT and CE in CSD group decreased significantly (P<0.01). CCK-8 results showed that compared with CG group, the activity of neurons in CA1 area of hippocampus in CSD group was significantly decreased (P<0.01), while that in CSD+E group was significantly increased (P<0.01); Annexin V/PI flow cytometry results showed that compared with CG group, the apoptosis of neurons in CA1 area of hippocampus in CSD group increased (P<0.01), and that in CSD+E group decreased significantly (P<0.01);Western blot results showed that caspase-12, Bax, IL-6, IL-1β and TNF-a were highly expressed and Bcl-1 was lowly expressed in hippocampal tissues of rats in the CSD group compared with the CG group (P<0.01), Wnt, β-catenin and p-β-catenin were lowly expressed in hippocampal tissues of rats in the CSD group, and Gsk-3βprotein expression was significantly higher (p<0.01). The results of RT-qPCR showed that caspase-12 mRNA, Bax mRNA, IL-6 mRNA, TNF-a mRNA and IL-1β mRNA were highly expressed and Bcl-1 mRNA was lowly expressed in hippocampal tissues of rats in the CSD group compared with the CG group (P<0.01). Compared with the CG group, Wnt mRNA and β-catenin mRNA were significantly lowly expressed and Gsk-3βmRNA was significantly highly expressed in hippocampal tissue of CSD rats (P<0.01). Our findings indicated that 8 weeks of aerobic exercise significantly improved anxiety-like depression in CSD rats by increasing neuronal activity, inhibiting apoptosis, reducing the inflammatory response and activating the Wnt/β-catenin pathway

Recombinant mycobacterium tuberculosis fusion protein for diagnosis of mycobacterium tuberculosis infection: a short-term economic evaluation

ObjectivesRecombinant Mycobacterium tuberculosis fusion protein (EC) was anticipated to be used for the scale-up of clinical application for diagnosis of Mycobacterium tuberculosis infection in China, but it lacked a head-to-head economic evaluation based on the Chinese population. This study aimed to estimate the cost-utility and the cost-effectiveness of both EC and tuberculin pure protein derivative (TB-PPD) for diagnosis of Mycobacterium tuberculosis infection in the short term.MethodsFrom a Chinese societal perspective, both cost-utility analysis and cost-effectiveness analysis were performed to evaluate the economics of EC and TB-PPD for a one-year period based on clinical trials and decision tree model, with quality-adjusted life years (QALYs) as the utility-measured primary outcome and diagnostic performance (including the misdiagnosis rate, the omission diagnostic rate, the number of patients correctly classified, and the number of tuberculosis cases avoided) as the effective-measured secondary outcome. One-way and probabilistic sensitivity analyses were performed to validate the robustness of the base-case analysis, and a scenario analysis was conducted to evaluate the difference in the charging method between EC and TB-PPD.ResultsThe base-case analysis showed that, compared with TB-PPD, EC was the dominant strategy with an incremental cost-utility ratio (ICUR) of saving 192,043.60 CNY per QALY gained, and with an incremental cost-effectiveness ratio (ICER) of saving 7,263.53 CNY per misdiagnosis rate reduction. In addition, there was no statistical difference in terms of the omission diagnostic rate, the number of patients correctly classified, and the number of tuberculosis cases avoided, and EC was a similar cost-saving strategy with a lower test cost (98.00 CNY) than that of TB-PPD (136.78 CNY). The sensitivity analysis showed the robustness of cost-utility and cost-effectiveness analysis, and the scenario analysis indicated cost-utility in EC and cost-effectiveness in TB-PPD.ConclusionThis economic evaluation from a societal perspective showed that, compared to TB-PPD, EC was likely to be a cost-utility and cost-effective intervention in the short term in China

Scattering Field Enhanced Biosensing Based on Sub-wavelength Split-ring Plasmonic Cavity With High Q-factor

Plasmonic structures are widely used in modern biosensor design. various plasmonic resonant cavities could efficiently achieve a high Q-factor, improving the local field intensity to enhance photoluminescence or SERS (Surface-Enhanced Raman Scattering) of small molecules. Also, the combination between virus-like particles and plasmonic structures could significantly influence the scattering spectrum and field, which is utilized as a method for biological particle detection. In this paper, we designed one kind of gold plasmonic cavity with the shape of a split-ring. An edge gap and a bonus center bulge are introduced in the split-ring structure. Our simulation is based on Finite Difference Time Domain (FDTD) method. Polarization Indirect Microscopic Imaging (PIMI) technique is used here to detect far-field mode distribution under the resonant wavelength. The simulation results demonstrate resonant peaks in the visible spectrum at about 600 nm with a Q-factor reaches to 74. Localized hot spots are generated by an edge dipole mode and a cavity hexapole mode at resonant wavelength, which is according to dark points in the PIMI sinδ image. Also, the split-ring cavity shows a sensitivity when combined with biological particles. The scattering distribution is evidently changed as a result of energy exchange between particles and split-ring cavity, indicating a promising possibility for biosensing

Sub-wavelength visualization of near-field scattering mode of plasmonic nano-cavity in the far-field

Spatial visualization of mode distribution of light scattering from plasmonic nanostructures is of vital importance for understanding the scattering mechanism and applications based on these plasmonic nanostructures. A long unanswered question in how the spatial information of scattered light from a single plasmonic nanostructure can be recovered in the far-field, under the constraints of the diffraction limit of the detection or imaging optical system. In this paper, we reported a theoretical model on retrieving local spatial information of scattered light by plasmonic nanostructures in a far-field optical imaging system. In the far-field parametric sin δ images, singularity points corresponding to near-field hot spots of the edge mode and the gap mode were resolved for gold ring and split rings with subwavelength diameters and feature sizes. The experimental results were verified with Finite Difference Time Domain (FDTD) simulation in the near-field and far-field, for the edge mode and the gap mode at 566 nm and 534 nm, respectively. In sin δ image of split-ring, two singularity points associated with near-field hot spots were visualized and resolved with the characteristic size of 90 and 100 nm, which is far below the diffraction limit. The reported results indicate the feasibility of characterizing the spatial distribution of scattering light in the far-field and with sub-wavelength resolution for single plasmonic nanostructures with sub-wavelength feature sizes