Impaired Permeability Research Articles

The Prognostic Value of Left Ventricular Function on Sepsis Outcomes in Critical Care Unit Patients

Background: Sepsis is the most prevalent life menacing condition presupposed patients’ admission to intensive care units. The underlying cardiovascular consequences of sepsis comprehended marvelous increase of the cardiac output, reduction of the peripheral vascular resistance along with impaired capillary permeability. Aim of the study: The present investigation was implemented to retrieve the prognostic value of LVF assessment using speckle tracking echocardiography (STE) among Egyptian adults, who admitted to the intensive care unit as a resultant impact of sepsis or septic shock. Methods: Patients admitted at the Critical Care Unit, who initially diagnosed with sepsis or septic shock within 8 hours. After fulfilling their criteria and being aged more than 18 years, they were eligible for inclusion in the study. All participants were submitted to rigorous history taking, clinical evaluation, laboratory assessment, and STE. The study embraced an overall 50 patients.. Results: Left ventricular longitudinal strain (LVGLS) was the only parameter which attained statistically significant highly positive correlation with SOFA score among septic shock patients (r = 0.794, p = 0.021). The results of this model revealed that LVGLS (p<0.001) attained high ability in the prediction of Sepsis-related Organ Failure Assessment (SOFA) score and Acute Physiologic and Chronic Health Evaluation (APACHE) score. Conclusions: The capability of STE investigation for the detection of left ventricular dysfunction among septic or septic shocked critically ill patients is a promising and feasible approach, which have a crucial impact on the prognosis of such patients.

Dysfunction of bloodbrain barrier and intrathecal immune response in patients with clinically isolated multiple sclerosis syndrome

The study is devoted to the evaluation of blood-brain barrier dysfunction and intrathecal synthesis of immunoglobulin G in patients with clinically isolated syndrome (CIS) of multiple sclerosis. The presence of oligoclonal bands and immunoglobulin G indicates an increased risk of multiple sclerosis in patients with CIS, regardless of the presence of other risk factors. An observational study of an intranasal response in patients with CIS was performed for the fi rst time in Ukraine. Based on the evaluation of cerebrospinal fl uid and blood parameters in 19 adult patients, it was found that 68 % of patients had an impairment of permeability of the blood-brain barrier. Synthesis of intrathecal immunoglobulin G is present in two thirds of cases. Key words: clinically isolated syndrome, multiple sclerosis, blood-barrier, intrathecal synthesis, immunoglobulin G

Survival of membrane-damaged Escherichia coli in a cytosol-mimicking solution

Selective permeability of cell membrane is critically important for cell survival. The damage caused to cell membrane by pore-forming antimicrobial peptides may result in the loss of selective permeability and leakage of intracellular molecules, eventually leading to cell death. Here, we examined whether the membrane-damaged Escherichia coli cells survive in a cytosol-mimicking solution (CMS), which compensates for the lethal leakage of intracellular molecules. We prepared a CMS comprising 34 low molecular weight compounds from the cytosol and found that the cells were able to grow in CMS even in the presence of a pore-forming peptide, melittin. We confirmed that the melittin-treated cells lost selective membrane permeability by staining with membrane-impermeable dyes, propidium iodide and SYTOX green. Some stained cells maintained the colony formation ability in CMS. These results provide an evidence that E.coli cells can at least partially survive in the CMS even after the temporary impairment of membrane selective permeability. This study demonstrates a technique that allows temporal loss of the selective permeability of the cell membrane while maintaining the viability of cells that may be useful for the introduction of membrane-impermeable molecules into E.coli cells.

Effect of aluminum oxide nanoparticles on the rheology and stability of a biopolymer for enhanced oil recovery

Uncommon and untested biopolymers in field pilot studies, but applied in laboratory studies are combined with Al2O3 nanoparticles to form nanocomposites for enhanced oil recovery (EOR) performance evaluation. Core plug samples of the Niger Delta region and Berea sandstone were used as the porous media for EOR experiments. Incremental oil recovery sequel to waterflooding (secondary recovery) was 5–12% and 5–7% for potato starch nanocomposite (PSPNP) and gum Arabic nanocomposite (GCNP) respectively. The biopolymer nanocomposites showed improved viscosity over the biopolymers. Thus, the nanoparticle served as a viscosity modifier on one-hand and stability enhancer on the other. EOR was affected by biopolymer and nanoparticle concentration with the attendant catch-22 situation of permeability impairment. The overall higher incremental recovery of applying PSPNP came by an intermediate potato starch (PSP) flooding between waterflooding and PSNP flooding. Consequently, slugs of biopolymer and biopolymer nanocomposite may be the way forward knowing that the biopolymers studied have surface-active constituents.

Silicon Ethoxide as reversible surfactant in reversible drilling mud and the mud’s effect on permeability

Decades of innovation, research and improvements have left drilling fluid vastly different from a mixture of water and clay but are now referred to as non-Newtonian fluids. For optimum well performance for new wells, drillers are to make a choice between drilling with pseudo oil based mud to achieve stability in difficult trajectories and risk permeability impairment; or drill with water based drilling fluid and risk possible drilling instability. Reversible emulsion based muds which can be converted using an acid-base chemical switch from water-in-oil (W/O) to oil-in-water (O/W) emulsion have been suggested as solution in literature. The effect of this acid-base chemical-switch reaction with drilling equipment and personnel prompted this study. Silicon Ethoxide was identified and applied in this study because it has the properties of a reversible surfactant and can be used to formulate a reversible mud that will not react with the drilling equipment nor the formation. Different measurements of Silicon Ethoxide were used, ranging from 5 ml to 45 ml, but we achieved reversibility from 30 ml. Three different base oils (EDC-99, Palm Kernel Oil and Polytriethanolamine) were also used. With the reversed emulsion mud systems, reduction in permeability within the range of 16–19 mD which is minimal was recorded. Thus, this mud system can be used close to the reservoir during drilling operation without encountering significant permeability impairment.

Targeting Burkitt lymphoma with a tumor cell–specific heptamethine carbocyanine‐cisplatin conjugate

BackgroundBurkitt lymphoma is a fast‐growing mature B cell malignancy, whose genetic hallmark is translocation and activation of the c‐myc gene. Prompt multiagent immunochemotherapy regimens can have favorable outcomes, but prognosis is poor in refractory or relapsed disease. We previously identified a novel family of near‐infrared heptamethine carbocyanine fluorescent dyes (HMCD or DZ) with tumor‐homing properties via organic anion‐transporting peptides. These membrane carriers have uptake in tumor cells but not normal cells in cell culture, mouse and dog tumor models, patient‐derived xenografts, and perfused kidney cancers in human patients.MethodsHere we report the cytotoxic effects of a synthesized conjugate of DZ with cisplatin (CIS) on B cell lymphoma CA46, Daudi, Namalwa, Raji, and Ramos cell lines in cell culture and in xenograft tumor formation. Impaired mitochondrial membrane permeability was examined as the mechanism of DZ‐CIS–induced lymphoma cell death.ResultsThe new conjugate, DZ‐CIS, is cytotoxic against Burkitt lymphoma cell lines and tumor models. DZ‐CIS retains tumor‐homing properties to mitochondrial and lysosomal compartments, does not accumulate in normal cells and tissues, and has no nephrotoxicity in mice. DZ‐CIS accumulated in Burkitt lymphoma cells and tumors induces apoptosis and retards tumor cell growth in culture and xenograft tumor growth in mice.ConclusionDZ‐CIS downregulated c‐myc and overcame CIS resistance in myc‐driven TP53‐mutated aggressive B cell Burkitt lymphoma. We propose that DZ‐CIS could be used to treat relapsed/refractory aggressive Burkitt lymphomas.

Proteomic Analysis of Endothelial Cells Exposed to Ultrasmall Nanoparticles Reveals Disruption in Paracellular and Transcellular Transport.

The large interactive surfaces of nanoparticles (NPs) increase the opportunities to develop NPs for vascular targeting. Proteomic analysis of endothelial cells exposed to NPs reveals the cellular response and turns the focus into the impairment of the endothelial permeability. Here, quantitative proteomics and transcriptome sequencing are combined to evaluate the effects of exposure to sub-lethal concentrations of TiO2 -USNPs and TiO2 -NPs on human dermal microvascular endothelial cells. Endothelial cells react to preserve the semi-permeable properties that are essential for vascular tissue fluid homeostasis, vascular development, and angiogenesis. The main impact of the exposure was alteration of functional complexes involved in cell adhesion, vesicular transport, and cytoskeletal structure. Those are the core cellular structures that are linked to the permeability and the integrity of the endothelial tissue. Moreover, the extracellular proteins uptake along wih the NPs into the endothelial cells escape the lysosomal degradation pathway. These findings improve the understanding of the interaction of NPs with endothelial cell. The effects of the studied NPs modulating cell-cell adhesion and vesicular transport can help to evaluate the distribution of NPs via intravenous administration.

Geochemical and hydrodynamic modeling of permeability impairment due to composite scale formation in porous media

Injectivity decline due to mineral scale deposition in near wellbore region of water injection wells is one of the main challenging issues and have been widely reported in the literature. One of the main mechanisms of injectivity loss is incompatibility between injected and formation waters that may result in inorganic scale precipitation and subsequent deposition in porous media. Reliable reactive flow models to predict type and amount of scale along with permeability decline estimation allow planning and risk management of water flood projects.In this paper, we present a coupled geochemical and hydrodynamic model to simulate the scale precipitation and deposition of mineral scales in multicomponent aqueous systems which is able to predict type of scale and permeability decline in porous medium. Geochemical software was used to simulate reactions between injected and formation brine suspicions to risk of composite scale formation and hydrodynamic flow model was applied to predict subsequent permeability decline during water injection. High quality match of permeability decline in following of robust static modeling of mineral scale formation in multicomponent aqueous systems was achieved.

Cinnamaldehyde Exerts Its Antifungal Activity by Disrupting the Cell Wall Integrity of Geotrichum citri-aurantii.

Our previous study showed that cinnamaldehyde (CA) significantly inhibited the mycelial growth of Geotrichum citri-aurantii, one of the main postharvest pathogens in citrus fruits. This study investigated the antifungal mechanism of CA against G. citri-aurantii. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images showed that CA treatment led to clear morphological changes in the cell walls and membranes of G. citri-aurantii. However, the membrane integrity, total lipids and ergosterol contents were not apparently affected by CA treatment. Notably, the extracellular alkaline phosphatase (AKP) activity was increased after CA treatment, suggesting impairment in cell wall permeability. A weakened fluorescence in the cell wall, a decrease in the chitin contents, and changes of ten genes involved in cell wall integrity were also observed. These results suggested that CA may exhibit its antifungal activity against G. citri-aurantii by interfering the build of cell wall and therefore lead to the damage of cell wall permeability and integrity.

Combining large-sized model flow experiment and NMR measurement to investigate drilling induced formation damage in sandstone reservoir

Since the dynamic process of drilling operation often cannot be duplicated realistically in laboratory environment, the methodology to evaluate drilling induced formation damage using the core plug is still open to question. By using a multifunctional physical simulation system of drilling mud invasion, this paper introduces a novel experimental methodology which organically combines large-sized model flow experiment and NMR measurement to investigate drilling induced formation damage in sandstone reservoir. A large-sized sandstone formation module (55.9 cm in radial depth, and 10 cm in thickness) instead of the conventional core plug is proposed. This new type of experimental aliquot is able to provide enough space for observing a relative greater damage depth in a long-term drilling mud invasion. The effects of formation permeability and overbalance pressure on the damage are analysised. The patterns of permeability impairment and pore structure change caused by the fresh water-based mud invasion are summarized. The results show that the formation permeability plays a negative leading role in both the damage depth and the damage degree. The damage depth of the drilling mud in the sandstone reservoir with a lower permeability is greater than that with a higher value. The former formation damage degree is also more severe than the latter one. For the same sandstone reservoirs, a higher overbalance pressure results in a greater damage depth and a more severe damage degree at the same radial depth. The decrease ratio of movable water based on NMR T2 distribution is an excellent index for describing the relationship between macroscopic performance and microcosmic essence of the formation damage. An obvious positive correlation between the permeability damage rate and the decrease ratio of movable water is observed. With the variation of decrease ratio of movable water, the permeability damage rate changes faster in the sandstone reservoir with a lower permeability. The results obtained in this paper provide some helpful insights for enlightening new laboratory evaluation methodologies, improving numerical simulation of drilling induced formation damage and researching formation damage caused by any other working fluids, such as completion, workover, and stimulation fluids.

Model development of permeability impairment due to clay swelling in porous media using micromodels

Swelling and displacement of clay minerals during drilling and production of oil and gas reservoirs are among the main mechanisms of formation damage. Most reservoirs contain clay minerals, either originally deposited during sedimentation phase, or precipitated from fluids flowing through matrix. Owing to the large specific surface area of clay particles, their swelling, detachment, and migrationmay lead to permeability impairment in porous media.Therefore, an accurate interpretation of the behaviour of clay particles in the porous media may enable us to prevent and possibly reverse the respective damage mechanisms. In this work, the pore-scale swelling behaviour of clays are studied using glass micro models as porous medium and Sodium bentonite as swelling clay. By image processing technique, effective porosity of model during low salinity water (LSW) flooding are estimated. The effect of different parameters such as porous medium aspect ratio and clay concentration on permeability impairment is studied. According to this study, besides higher clay concentrations, the permeability is also affected adversely by larger aspect ratio of pore bodies. Based on our experiments, a model is developed to estimate permeability impairment by clay swelling as a function of pore geometry and clay concentration.

Comparative characteristic of laboratory indicators for encephalitis, disseminated encephalomyelitis and multiple sclerosis in children

Background. The similarity of the clinical manifestations of encephalitis (E), disseminated encephalomyelitis (DEM) and multiple sclerosis (MS) in children, the complexity of predicting the nature of the course and outcome of diseases determines the search for additional diagnostic and prognosis criteria.Objective: a comparative characteristic of laboratory indicators for E, DEM and RS in children to assess their diagnostic and prognostic value.Materials and methods. Fifty six children (14 children with E, 14 – with DEM, 28 – with MS) and 16 children of the control group (with acute respiratory virus infection) at the age from 10 to 17 years were examined. Laboratory methods included standard studies of cerebrospinal fluid (protein, cytosis), determination of concentrations of albumin and immunoglobulin G (IgG) in cerebrospinal fluid and serum with subsequent calculation of protein indices (albumin, immunoglobulin, intrathecal immunoglobulin G indexes).Results. With all nosological forms in the serum there were no significant differences between albumin and IgG from the control group, whereas in the cerebrospinal fluid an excess of the concentration of IgG was detected at a normal level of albumin. An increase in the albumin index was found only in E, whereas the immunoglobulin index was significantly higher than the norm in all groups of patients. A significant spread of the intrathecal IgG index (from 0.1 to 11.9) was found, which determined the analysis of clinical and laboratory parameters by subgroups, depending on its magnitude. The maximum incidence of increased intrathecal IgG synthesis was detected in children with MS (with exacerbation of MS – 74 %, in remission – 67 %), whereas in E and DEM, an increase was observed in about half of the patients surveyed and associated with a more favorable course of the disease.Conclusion. The data obtained make it possible to assert that, despite the commonness of some pathogenetic mechanisms, there are differences in the degree of impaired permeability of the blood brain barrier, the intensity of the systemic and intrathecal humoral immune response in E, DEM and RS, which may determine the features of their course and the outcome of the disease, including the transformation of the DEM in the RS.

Immuno-PET of Innate Immune Markers CD11b and IL-1β Detects Inflammation in Murine Colitis

Inflammatory bowel disease (IBD) is a chronic relapsing and remitting inflammatory disease of the gastrointestinal tract. The diagnosis and monitoring of IBD are reliant on endoscopy, which is invasive and does not provide information on specific mediators. Symptom flare in IBD is associated with increased activation of innate immune pathways. Immuno-PET approaches have previously demonstrated the ability to detect colitis; however, a direct comparison of antibodies targeted to innate immune mediators and cells has not been done. We aimed to compare immuno-PET of antibodies to IL-1β and CD11b against standard 18F-FDG and MRI approaches to detect colonic inflammation. Methods: Colonic concentrations of IL-1β and myeloperoxidase were determined by ELISA, and colonic infiltration by CD11b-positive CD3-negative innate immune cells was determined by flow cytometry and compared between healthy and dextran sodium sulphate-treated colitic mice. PET of 89Zr-lα-IL-1β, 89Zr-α-CD11b, and 18F-FDG was compared by volume-of-interest analysis and with MRI by region-of-interest analysis. Imaging results were confirmed by ex vivo biodistribution analysis. Results: Colonic inflammation was associated with impaired colonic epithelial barrier permeability, increased colonic IL-1β and myeloperoxidase concentrations, and increased CD11b-positive CD3-negative innate immune cell infiltration into the colon. 89Zr-α-IL-1β and 89Zr-α-CD11b immuno-PET detected colonic inflammation, as did 18F-FDG, and all PET tracers were more sensitive than MRI. Although 18F-FDG volumes of interest correlated with colitis severity and a strong trend was observed with 89Zr-α-IL-1β, no correlation was observed for 89Zr-α-CD11b or MRI. 89Zr-α-IL-1β was distributed mainly to the gastrointestinal tract, whereas 89Zr-α-CD11b was distributed to more tissue types. Conclusion: Immuno-PET using antibodies directed to innate immune markers detected colonic inflammation, with 89Zr-α-IL-1β providing a more tissue-specific signal than 89Zr-α-CD11b. Development of these technologies for human subjects will potentially provide a less invasive approach than endoscopy for diagnosing and monitoring IBD.

Experimental Investigation of Asphaltene-Induced Formation Damage Caused by Pressure Depletion of Live Reservoir Fluids in Porous Media

Summary One of the complex processes of permeability impairment in porous media, especially in the near-wellbore region, is asphaltene-induced formation damage. During production, asphaltene particles precipitate out of the bulk fluid phase because of pressure drop, which might result in permeability reduction caused by both deposition of asphaltene nanoparticles on porous-medium surfaces and clogging of pore throats by larger asphaltene agglomerates. Experimental data will be used to identify the parameters of an impairment model being developed. As part of a larger effort to identify key mechanisms of asphaltene deposition in porous media and develop a model for asphaltene impairment by pressure depletion, this paper focuses on a systematic design and execution of an experimental study of asphaltene-related permeability damage caused by live-oil depressurization along the length of a flow system. An experiment was performed using a custom-designed 60-ft slimtube-coil assembly packed with silica sands to a permeability of 55 md. The customized design included a number of pressure gauges at regular intervals along the coil length, which enabled real-time measurement of the fluid-pressure profile across the full length of the slimtube coil. The test was performed on a well-characterized recombined live oil from the Gulf of Mexico (GOM) that is a known problematic asphaltenic oil. Under a constant differential pressure, the injection flow rate of the live oil through the slimtube coil decreased over time as the porous medium became impaired. During the impairment stage, samples of the produced oil were collected on a regular basis for asphaltene-content measurement. After more than 1 month, the impairment test was terminated; the live oil was purged from the slimtube coil with helium at a pressure above the asphaltene-onset pressure (AOP); and the entire system was gently depressurized to bring the coil to atmospheric conditions while preserving the asphaltene-damaged zones of the coil. The permeability and porosity of the porous medium changed because of asphaltene impairment that was triggered by pressure depletion. Results indicated that the coil permeability was impaired by approximately 32% because of pressure depletion below the AOP, with most of the damage occurring in the latter section of the tube, which operated entirely below the AOP. Post-analytical studies indicated lower asphaltene content of the produced-oil samples compared with the injecting fluid. The distribution of asphaltene deposits along the length of the coil was determined by cutting the slimtube coil into 2- to 3-ft-long sections and using solvent extraction to collect the asphaltenes in each section. The extraction results confirmed that the observed permeability impairment was indeed caused by asphaltene deposition in the middle and latter sections of the coil, where the pressure was less than the AOP. With the success of this experiment, the same detailed analysis can be extended to a series of experiments to determine the effects of different key parameters on pressure-induced asphaltene impairment, including flow rate, wettability, and permeability.

Therapeutic Implications of Human Umbilical Cord Mesenchymal Stromal Cells in Attenuating Influenza A(H5N1) Virus-Associated Acute Lung Injury.

Highly pathogenic avian influenza viruses can cause severe forms of acute lung injury (ALI) in humans, where pulmonary flooding leads to respiratory failure. The therapeutic benefits of bone marrow mesenchymal stromal cells (MSCs) have been demonstrated in a model of ALI due to influenza A(H5N1) virus. However, clinical translation is impractical and limited by a decline in efficacy as the age of the donor increases. Umbilical cord MSCs (UC-MSCs) are easier to obtain by comparison, and their primitive source may offer more-potent therapeutic effects. Here we investigate the therapeutic efficacy of UC-MSCs on the mechanisms of pulmonary edema formation and alveolar fluid clearance and protein permeability of A(H5N1)-infected human alveolar epithelial cells. UC-MSCs were also tested in a mouse model of influenza ALI. We found that UC-MSCs were effective in restoring impaired alveolar fluid clearance and protein permeability of A(H5N1)-infected human alveolar epithelial cells. UC-MSCs consistently outperformed bone marrow MSCs, partly because of greater growth factor secretion of angiopoietin 1 and hepatocyte growth factor. Conditioned UC-MSC medium and UC-MSC exosomes were also able to recapitulate these effects. However, UC-MSCs only slightly improved survival of A(H5N1)-infected mice. Our results suggest that UC-MSCs are effective in restoring alveolar fluid clearance and protein permeability in A(H5N1)-associated ALI and confer functional in addition to practical advantages over conventional bone marrow MSCs.

A new model for permeability impairment due to asphaltene deposition

The existing theoretical and empirical models to describe asphaltene deposition in porous media do not consider the complicated structure of pore network. Permeability reduction due to asphaltene deposition has been mainly attributed to pore volume shrinkage (porosity reduction). However, asphaltene particles can also block pore throats which will lead to severe permeability reduction even when a large fraction of total pore volume still remains intact. Thus, there is a need for permeability models that are explicitly function of pore/hydraulic connectivity. This paper provides a review of the existing models and examines a permeability model that explain permeability impairment due to asphaltene deposition.In this study, we propose a new permeability model based on Critical Path Analysis (CPA) which is a function of average coordination number (average number of available/connected neighbor pores). Furthermore, experimental data in the literature related to limestone, sandstone and carbonate (dolomite) samples are utilized to understand combined effects of surface deposition and interconnectivity loss due to pore blockage on permeability reduction.We observed that surface deposition is the dominant mechanism in the limestone samples studied here owing to large pore throat size compared to the particle size. In the sandstone samples, both the surface deposition and pore throat plugging mechanisms contribute fairly the same in the observed permeability reduction. For the carbonate (dolomite) samples, the pore blockage is the dominant mechanism, which results in rapid sharp decrease of the permeability. It is expected that the outcome of this work improves prediction of the asphaltene deposition in the near wellbore region.

A Study on Particle Suspension Flow and Permeability Impairment in Porous Media Using LBM–DEM–IMB Simulation Method

The paper studies the particle retention and permeability impairment in porous media. This problem results from the re-injection of produced groundwater during oil production into the oilfields in order to reduce environmental damage. The lattice Boltzmann method (LBM) is used to simulate the fluid flow. The discrete element method (DEM) is adopted to simulate the particle motion. The fluid–solid interactions are simulated using the immersed moving boundary method (IMB). Based on the coupling LBM–DEM–IMB method, the paper studies the effect of particle diameter, flow rate, particle volume fraction and injection amount on the particle retention and permeability impairment. Results indicate that larger particle diameter, lower flow rate, higher volume fraction and more particle injection lead to more severe permeability impairment. In order to further study the effect of particle suspensions on heterogeneous reservoirs, a two-channel model with different permeabilities is established. The simulations show that smaller particles tend to retain in the low permeable channel and its permeability impairment is more severe. On the contrary, larger particles can reduce the permeability of high permeable channel, but they can protect the permeability of low permeable channel due to the mechanism of membrane filtration. Therefore, the sweep efficiency and oil recovery of the heterogeneous reservoirs can be improved by re-injecting produced groundwater after reasonable pretreatment. The re-injection also reduces environmental damage resulting from the large amounts of produced water in petroleum engineering. This paper provides some references for general studies on the flow of particle suspension in porous media.

Fecal Enterobacteriales enrichment is associated with increased invivo intestinal permeability in humans.

Type 2 diabetes (T2D) has been linked with increased intestinal permeability, but the clinical significance of this phenomenon remains unknown. The objective of this study was to investigate the potential link between glucose control, intestinal permeability, diet and intestinal microbiota in patients with T2D. Thirty‐two males with well‐controlled T2D and 30 age‐matched male controls without diabetes were enrolled in a case–control study. Metabolic parameters, inflammatory markers, endotoxemia, and intestinal microbiota in individuals subdivided into high (HP) and normal (LP) colonic permeability groups, were the main outcomes. In T2D, the HP group had significantly higher fasting glucose (P = 0.034) and plasma nonesterified fatty acid levels (P = 0.049) compared with the LP group. Increased colonic permeability was also linked with altered abundances of selected microbial taxa. The microbiota of both T2D and control HP groups was enriched with Enterobacteriales. In conclusion, high intestinal permeability was associated with poorer fasting glucose control in T2D patients and changes in some microbial taxa in both T2D patients and nondiabetic controls. Therefore, enrichment in the gram‐negative order Enterobacteriales may characterize impaired colonic permeability prior to/independently from a disruption in glucose tolerance.

Massive fines detachment induced by moving gas-water interfaces during early stage two-phase flow in coalbed methane reservoirs

Field observations have shown that the concentration of fines produced during the early two-phase flow stage in coalbed methane (CBM) reservoirs is much higher than single-phase water flow, leading to more frequent workover activities. The typical flow pattern in early two-phase flow is bubble-water flow, in which the liquid phase is mostly contained in the form of liquid “plugs”, separated by a series of moving bubbles/gas-water interfaces (GWIs). Here, we quantify the impact of moving bubbles/GWIs on fines detachment, aiming at better understanding of fines mobilization mechanisms in bubble-water flow towards their effective control. First, fines migration tests in the absence and presence of moving bubbles in water flow, including effluent and permeability measurements, were conducted on fractured coal plugs. The experimental flow velocity was less than the critical flow velocity (CFV) for massive fines release. Experimental results showed that both peak effluent concentration and permeability impairment in the presence of moving bubbles were much greater than when absent, indicating that the quantity of fines detached by moving bubbles/GIWs was much larger than simply by water flow. Second, forces and torques acting on coal fines were analyzed to determine the combined effects of extended Derjaguin-Landau-Verwey-Overlook (DLVO), hydrodynamic, surface tension, and frictional forces on fines mobilization. Theoretical results showed that all in-situ fines could be mobilized by moving GWIs, whereas no fines could be released by water flow when the flow velocity is smaller than the CFV, as the surface tension force arising from passing GWIs greatly dominates hydrodynamic forces by 2–4 orders of magnitude. Theoretical results support experimental data, in spite of some errors due to model assumptions, i.e., spherical fines and homogenous surface.

Effect of Wettability Changes on Evaporation Rate and the Permeability Impairment due to Salt Deposition

Pore-scale visualization was employed to investigate evaporative drying of brine and associated salt deposition at different wetting conditions, using a 2.5D etched-silicon/glass micromodel based on a thin section image of a carbonate rock. We also compared air drying with CO2 drying, with the latter having important applications in CO2 sequestration processes. The resulting permeability impairment was also measured. For deionized water in a water-wet model, we observed the three classical periods of evaporation: the constant rate period (CRP), the falling rate period (FRP), and the receding front period (RFP). The length of the deionized water CRP was much shorter for a uniformly oil-wet model, but mixed wettability made little difference to the drying process. For brine systems at all wetting conditions, the dry area became linear with the square root of time after a short CRP. This is due to the deposited salt acting as a physical barrier to hydraulic connectivity, unlike the case of deionized water, w...