Search

This paper presents a new fractal seepage model to study the decrease in seepage capacity caused by fluid erosion and pressure changes in porous media. The normalized permeability obtained by our model is in good agreement with the experiments and models in literature and has high accuracy and usability. The results demonstrate that: (1) the larger the instability coefficient, the higher the particle stability, the better the permeability of the porous medium, the later the normalized permeability decreases, and the slower it goes down, and (2) the fractal dimension of the solid skeleton set mainly affects the porosity and permeability of porous media, independent of the stability of solid particles. (3) The fractal dimension of movable particles is one of the main factors affecting the normalized permeability, it does not affect the instability conditions solid-phase particles in the porous media. The proposed model makes full use of the microstructure parameters of porous media, further reveals the mechanism of fluid flow in porous media with particle shedding, and provides a sound theoretical basis for various practical applications in petroleum engineering and other industries. [ABSTRACT FROM AUTHOR]

We previously found that the disorder of soluble epoxide hydrolase (sEH)/cyclooxygenase-2 (COX-2)-mediated arachidonic acid (ARA) metabolism contributes to the pathogenesis of the non-alcoholic fatty liver disease (NAFLD) in mice. However, the exact mechanism has not been elucidated. Accumulating evidence points to the essential role of cellular senescence in NAFLD. Herein, we investigated whether restoring the balance of sEH/COX-2-mediated ARA metabolism attenuated NAFLD via hepatocyte senescence. A promised dual inhibitor of sEH and COX-2, PTUPB, was used in our study to restore the balance of sEH/COX-2-mediated ARA metabolism. In vivo, NAFLD was induced by a high-fat diet (HFD) using C57BL/6J mice. In vitro, mouse hepatocytes (AML12) and mouse hepatic astrocytes (JS1) were used to investigate the effects of PTUPB on palmitic acid (PA)-induced hepatocyte senescence and its mechanism. PTUPB alleviated liver injury, decreased collagen and lipid accumulation, restored glucose tolerance, and reduced hepatic triglyceride levels in HFD-induced NAFLD mice. Importantly, PTUPB significantly reduced the expression of liver senescence-related molecules p16, p53, and p21 in HFD mice. In vitro, the protein levels of γH2AX, p53, p21, COX-2, and sEH were increased in AML12 hepatocytes treated with PA, while Ki67 and PCNA were significantly decreased. PTUPB decreased the lipid content, the number of β-gal positive cells, and the expression of p53, p21, and γH2AX proteins in AML12 cells. Meanwhile, PTUPB reduced the activation of hepatic astrocytes JS1 by slowing the senescence of AML12 cells in a co-culture system. It was further observed that PTUPB enhanced the ratio of autophagy-related protein LC3II/I in AML12 cells, up-regulated the expression of Fundc1 protein, reduced p62 protein, and suppressed hepatocyte senescence. In addition, PTUPB enhanced hepatocyte autophagy by inhibiting the PI3K/AKT/mTOR pathway through Sirt1, contributing to the suppression of senescence. PTUPB inhibits the PI3K/AKT/mTOR pathway through Sirt1, improves autophagy, slows down the senescence of hepatocytes, and alleviates NAFLD. [ABSTRACT FROM AUTHOR]

Necroptosis, a recently described form of programmed cell death, is the main way of alveolar epithelial cells (AECs) death in acute lung injury (ALI). While the mechanism of how to trigger necroptosis in AECs during ALI has been rarely evaluated. Long optic atrophy protein 1 (L‐OPA1) is a crucial mitochondrial inner membrane fusion protein, and its deficiency impairs mitochondrial function. This study aimed to investigate the role of L‐OPA1 deficiency‐mediated mitochondrial dysfunction in AECs necroptosis. We comprehensively investigated the detailed contribution and molecular mechanism of L‐OPA1 deficiency in AECs necroptosis by inhibiting or activating L‐OPA1. First, our data showed that L‐OPA1 expression was downregulated in the lungs and AECs under the lipopolysaccharide (LPS) challenge. Furthermore, inhibition of L‐OPA1 aggravated the pathological injury, inflammatory response, and necroptosis in the lungs of LPS‐induced ALI mice. In vitro, inhibition of L‐OPA1 induced necroptosis of AECs, while activation of L‐OPA1 alleviated necroptosis of AECs under the LPS challenge. Mechanistically, inhibition of L‐OPA1 aggravated necroptosis of AECs by inducing mitochondrial fragmentation and reducing mitochondrial membrane potential. While activation of L‐OPA1 had the opposite effects. In summary, these findings indicate for the first time that L‐OPA1 deficiency mediates mitochondrial fragmentation, induces necroptosis of AECs, and exacerbates ALI in mice. [ABSTRACT FROM AUTHOR]

When a spherical droplet moves parallel to the direction of motion of its surrounding gas medium, it will deform into an ellipsoidal droplet. In this paper, an exposition of a novel model for predicting the minimum flow rate for the continuous removal of liquids from gas wells based on two theories is presented. First, droplet breakup principle is utilized to microscopically obtain the maximum size parameters of ellipsoidal droplets, and second, droplet force equilibrium is adopted to macroscopically calculate the critical droplet entrainment rate. Moreover, effect of variations in the windward area (attributed to droplet deformation) on the drag coefficient is determined. Impacts of variations in pressure, temperature, and pipe diameter on the gas‐liquid two‐phase friction resistance and gas‐liquid surface tension are also considered. For model verification and comparison with other droplet entrainment models, field data from 3436 gas wells are utilized. The field data well validates the results with a 92% accuracy, indicating that the new model has a better comprehensive performance in determining whether or not a gas well is loaded. Besides, parameter sensitivity analyses including the effects of drag coefficient, surface tension, and friction coefficient on the minimum flow rate of gas are performed. Finally, the relationship curve of critical droplet entrainment rates corresponding to different pressures and pipe diameters is established. [ABSTRACT FROM AUTHOR]

Performing stress‐sensitivity evaluation on a high‐temperature and high‐pressure gas reservoir is essential for correctly understanding the characteristics of physical property changes and reasonably designing the development scheme of a reservoir under stratum conditions. By focusing on six core samples with different physical properties in a gas field in the Yingqiong Basin, stress‐sensitivity experiments have been conducted along with mercury intrusion porosimetry and X‐ray diffraction measurements to study the relationship among porosity, permeability, and effective stress at a temperature of 140°C and effective stress ranging from 2 MPa to 70 MPa. Our results showed that the stress‐sensitivity curve characterized by three‐stage segmentation is primarily affected by average pore radius and mineral composition but has no direct relation with porosity and permeability. Meanwhile, the stress sensitivity of permeability is mainly related to the average pore throat radius and mineral composition of core specimen. The smaller the pore throat radius and the higher the clay content, the stronger the stress sensitivity of permeability. Under high‐temperature and high‐pressure conditions, the stress sensitivities of permeability and porosity can be characterized by power functions although the stress sensitivity of permeability is about 2–11 times higher than that of porosity. [ABSTRACT FROM AUTHOR]

Most researches of the threshold pressure gradient in tight gas reservoirs are experimental and mainly focus on the transient pressure response, without paying much attention to the transient rate decline. This paper establishes a dual-porosity rate transient decline model for the horizontal well with consideration of the threshold pressure gradient, which represents the non-Darcy flow in a fracture system. The solution is obtained by employing the Laplace transform and the orthogonal transform. The bi-logarithmic type curves of the dimensionless production rate and derivative are plotted by the Stehfest numerical inversion method. Seven different flow regimes are identified and the effects of the influence factors such as the threshold pressure gradient, the elastic storativity ratio, and the cross flow coefficient are discussed. The presented research could interpret the production behavior more accurately and effectively for tight gas reservoirs. [ABSTRACT FROM AUTHOR]

In previous studies, it is found that the frame and pore in porous media both possess the fractal geometric character. So the permeability and porosity models of bi-fractal porous media are derived based on the assumption that a porous media consists of fractal solid clusters and capillary bundles. The expressions of presented models are constituted by the fractal parameters of solid cluster and those of capillary bundle. Good agreement between model predictions and experimental data is obtained. This verifies the validity of the permeability and porosity models for bi-fractal porous media. The sensitive parameters that influence the permeability and porosity are specified, and their effects on the relationship between permeability and porosity are discussed. [ABSTRACT FROM AUTHOR]

Horizontal well (HW) was divided into several elements after acidizing. In each element, there would exist a composite zone that was made up of damage zone (DZ) and acidizing zone (AZ). Local skin factor after acidizing was used to describe the resistance in each composite zone. The models for local skin factor and productivity of HW were created using the method of equivalent filtration resistance and displacement between two similar flow modes. According to the solution of the models, type curves of skin factor and production-increasing ratio after acidizing were illustrated, and the effect of different parameters in DZ and AZ on distribution of skin factor and production-increasing ratio after acidizing were discussed. The present model has a significant guide on the practice of acidizing technology. [ABSTRACT FROM AUTHOR]

After multistage fracturing, the flowback of fracturing fluid will cause two-phase flow through hydraulic fractures in shale gas reservoirs. With the consideration of two-phase flow and desorbed gas transient diffusion in shale gas reservoirs, a two-phase transient flow model of multistage fractured horizontal well in shale gas reservoirs was created. Accurate solution to this flow model is obtained by the use of source function theory, Laplace transform, three-dimensional eigenvalue method, and orthogonal transformation. According to the model’s solution, the bilogarithmic type curves of the two-phase model are illustrated, and the production decline performance under the effects of hydraulic fractures and shale gas reservoir properties are discussed. The result obtained in this paper has important significance to understand pressure response characteristics and production decline law of two-phase flow in shale gas reservoirs. Moreover, it provides the theoretical basis for exploiting this reservoir efficiently. [ABSTRACT FROM AUTHOR]

A model for transient flow in porous media embedded with randomly distributed tree-shaped fractal networks was presented based on the fractal properties of tree-shaped capillaries and generalized Darcy's law. The dimensionless expression of flowing pressure was developed using the Laplace transform and Stehfest numerical inversion method. The bilogarithmic type curves were illustrated and the influences of different fractal factors on dimensionless flowing pressure were also discussed. The presented study indicated that the fractal characteristics for the tree-shaped fractal networks should be considered in analysis of transient flow in the heterogeneous porous media. The proposed model may be conducible to a better understanding of the mechanism for transient flow in the multi-porosity porous media. [ABSTRACT FROM AUTHOR]

A permeability model for porous media considering the stress sensitivity is derived based on mechanics of materials and the fractal characteristics of solid cluster size distribution. The permeability of porous media considering the stress sensitivity is related to solid cluster fractal dimension, solid cluster fractal tortuosity dimension, solid cluster minimum diameter and solid cluster maximum diameter, Young's modulus, Poisson's ratio, as well as power index. Every parameter has clear physical meaning without the use of empirical constants. The model predictions of permeability show good agreement with those obtained by the available experimental expression. The proposed model may be conducible to a better understanding of the mechanism for flow in elastic porous media. [ABSTRACT FROM AUTHOR]

A transient flow model for power-law fluid in fractal porous media is derived by combining transient flow theory with the fractal properties of tortuous capillaries. Pressure changes of transient flow for power-law fluid in fractal porous media are related to pore fractal dimension, tortuosity fractal dimension and the power-law index. Additionally, the starting pressure gradient model of power-law fluid in fractal porous media is established. Good agreement between the predictions of the present model and that of the traditional empirical model is obtained, the sensitive parameters that influence the starting pressure gradient are specified and their effects on the starting pressure gradient are discussed. [ABSTRACT FROM AUTHOR]

On the base of some kinetics model analysis and kinetic observation of hydrate formation process, a new prediction model of gas hydrate formation is proposed. The analysis of the present model shows that the formation of gas hydrate not only relevant with gas composition and free water content but also relevant with temperature and pressure. Through contrast experiment, the predicted result of the new prediction method of gas hydrate crystallization kinetics is close to measured result, it means that the prediction method can reflect the hydrate crystallization accurately. [ABSTRACT FROM AUTHOR]

Abstract: Objective: This study aims to establish and evaluate the methodology of isolated rabbit eye (IRE) test. Methods: IRE test was performed according to modifications of the in vitro toxicology (INVITTOX) Protocol No.85: Rabbit enucleated eye test by European Centre for the Validation of Alternative Methods (ECVAM), and then 26 chemicals and 26 cosmetic products were tested in both in vitro IRE and in vivo Draize tests. A statistical analysis was conducted to determine the relevance of the IRE test to the data generated in the Draize test. Results: IRE test was established successfully in our laboratory. It was shown that ranking correlation and class concordance were fairly well between the IRE test and the Draize test for 26 reference chemicals (Fisher''s Exact Test χ2=51.314, P<0.001; McNemar P=0.261; Gamma=0.960, P<0.001; Kappa=0.843, P<0.001) and 26 cosmetic products (Fisher''s Exact Test χ2=15.522, P<0.001; McNemar P=0.311; Gamma=0.967, P<0.001; Kappa=0.611, P<0.001). Conclusion: IRE test was established successfully for in vitro testing of eye irritation as an alternative to Draize test. [Copyright &y& Elsevier]

Abstract: Background: Genetic variants of the genes encoding HIV-1 co-receptors and their ligands, CCR5-Δ32, CCR5m303A, CCR2-64I and SDF1-3′A, are implicated in the susceptibility to HIV-1 infection, and the prevalence of these mutations varies by ethnicity. However, little is known about their distribution in Uighurs. Objectives: This study aimed at characterizing the frequency of these HIV-related gene variants in a high-risk Uighur population. Study designs: A total of 251 HIV-1 seropositive and 238 seronegative high-risk Uighurs were recruited and their genotypes of CCR5-Δ32, CCR5m303A, CCR2-64I and SDF1-3′A were analyzed by PCR and PCR-ligase detection reaction (PCR-LDR). Results: The allelic frequency of CCR5-Δ32, CCR5m303A, CCR2-64I and SDF1-3′A was 4.40%, 2.66%, 25.66% and 57.36%, respectively, in this population. Apparently, the Uighur population has low frequency of CCR5-Δ32 and CCR5m303A, but high frequency of CCR2-64I and SDF1-3′A. While there was no significant difference in the frequency of CCR5-Δ32, CCR2-64I and SDF1-3′ A between HIV-1 seropositive and seronegative groups the frequency of CCR5m303A in HIV-1 seropositive group was significantly higher than that in seronegative group (P =0.006, OR=3.982 and 95%CI 1.514–10.476). Conclusions: Our data suggest that the CCR5-Δ32, CCR2-64I and SDF1-3′A variants may have limited effect on protecting from HIV-1 infection in Uighurs. Rather, the CCR5m303A may be associated with the risk for HIV-1 infection in high-risk Uighurs. [Copyright &y& Elsevier]

Multidrug-resistant Edwardsiella tarda threatens both sustainable aquaculture and human health, but the control measure is still lacking. In this study, we adopted functional proteomics to investigate the molecular mechanism underlying norfloxacin (NOR) resistance in E. tarda . We found that E. tarda had a global proteomic shift upon acquisition of NOR resistance, featured with increased expression of siderophore biosynthesis and Fe 3+ -hydroxamate transport. Thus, either inhibition of siderophore biosynthesis with salicyl-AMS or treatment with another antibiotic, kitasamycin (Kit), which was uptake through Fe 3+ -hydroxamate transport, enhanced NOR killing of NOR-resistant E. tarda both in vivo and in vitro . Moreover, the combination of NOR, salicyl-AMS, and Kit had the highest efficacy in promoting the killing effects of NOR than any drug alone. Such synergistic effect not only confirmed in vitro and in vivo bacterial killing assays but also applicable to other clinic E. tarda isolates. Thus, our data suggest a proteomic-based approach to identify potential targets to enhance antibiotic killing and propose an alternative way to control infection of multidrug-resistant E. tarda .

Objective: To determine the presence of vasculogenic mimicry (VM) and expression of Sphingosine kinase 1 (SphK1) and Connexin43 (Cx43) in colorectal cancer (CRC) tissues, and to identify their inter-relationships and associations with multiple pathologic parameters., Methods: Ninety-two CRC specimens and normal pericarcinoma tissues were analyzed for expression of SphK1 and Cx43 using immunohistochemistry, and for identification of VM using CD34-periodic acid-Schiff dual staining., Results: The positive rate of SphK1 expression was greater in CRC cells than pericarcinoma cells (85.87% vs. 33.70%, P < 0.05). In contrast, the positive rate of Cx43 expression was greater in pericarcinoma cells than in CRC cells (58.70% vs. 92.39%, P < 0.05). Analysis of CRC tissues indicated that expression of SphK1 was associated with poor differentiation, advanced tumor stage, lymph node metastasis, and the presence of VM ( P < 0.05 for each comparison). Expression of Cx43 was associated with high differentiation and the presence of VM ( P < 0.05 for each comparison). Patient sex, age, tumor size, depth of invasion, and distant metastasis were unrelated to the expression of either protein. There was a significant correlation between the expression of SphK1 and Cx43 ( P < 0.05). Analysis of overall patient survival indicated that SphK1 positivity and the presence of VM were significantly associated with poor survival, but Cx43 positivity had no relationship with survival., Conclusion: SphK1 protein expression was significantly greater in CRC tissues than pericarcinoma tissues, suggesting this protein may be associated with the pathogenesis of CRC. In addition, the significant correlation between expression of SphK1 and Cx43 in CRC tissues suggests their interaction may impact the pathogenesis of CRC., Competing Interests: None., (IJCEP Copyright © 2018.)

Lung diseases in neonates can be life-threatening condition and may result in respiratory failure and death. Chest X-ray is a traditional diagnostic technique that results in radiation exposure to patients. Lung ultrasound is a user-friendly imaging technique that has been increasingly used in clinical practice in recent years and presents the advantages of real-time imaging and without radiation. Here we review the sonographic appearances of common neonatal lung diseases and present demonstration of typical cases., Competing Interests: Conflicts of Interest: The authors have no conflicts of interest to declare.

Cytokine-induced killer (CIK) cell therapy, an adoptive T-cell immunotherapy, has been reported to be a safe and effective mode of treatment for patients with metastatic diseases, lymphoma and acute leukaemia. To investigate the clinical efficacy of cytokine-induced killer cells for the treatment of refractory lymphoma, the present clinical study was conducted. A total of 8 male patients with a mean age of 41 years (range 22-65) who were pathologically diagnosed with malignant lymphoma (Hodgkin's disease, 2 and non-Hodgkin's lymphoma, 6) were enrolled. CIK cells were expanded by priming with IFN-γ, monoclonal antibody (mAb) to CD3 and IL-1α, followed by the addition of IL-2 the following day using peripheral blood mononuclear cells (PBMCs) of the 8 male patients. The CIK cells were then transfused back to the patients as treatment. On day 13, the CIK cell count reached 7-18×10(19) (mean, 12.7×10(9)), a 44- to 140-fold increase (mean, 98-fold). The average percentage of cells expressing CD3(+), CD4(+), CD8(+) and CD3(+)CD56(+) were also increased from 50.9±3.5, 29.9±1.7, 41.3±3.2, 1.6±0.2% to 90.2±1.6, 40.6±5.5, 52.8±4.9 and 33.1±4.0%, respectively. Patients showed measurable radiographic tumor reduction, increased T-cell subset levels, and relief of symptoms after treatment. No severe toxicity or side effects were reported. CIK cells developed by this culture method have a high in vitro proliferation rate and tumor-killing capacity. In conclusion, CIK cell treatment of patients with malignant lymphoma achieves effective clinical responses, causing few side effects.

Aim: Oncolytic adenovirus, also called conditionally replicating adenovirus (CRAD), can selectively propagate in tumor cells and cause cell lysis. The released viral progeny can infect neighboring cancer cells, initiating a cascade that can lead to the ultimate destruction of the tumor. Suicide gene therapy using herpes simplex virus thymidine kinase (HSV-TK) and ganciclovir (GCV) offers a potential treatment strategy for cancer and is undergoing preclinical trials for a variety of tumors. We hypothesized that HSV-TK gene therapy combined with oncolytic adenoviral therapy would have an enhanced effect compared with the individual effects of the therapies and is a potential novel therapeutic strategy to treat liver cancer., Methods: To address our hypothesis, a novel CRAD was created, which consisted of a telomerase-dependent oncolytic adenovirus engineered to express E1A and HSV-TK genes (Ad-ETK). The combined effect of Ad-ETK and GCV was assessed both in vitro and in vivo in nude mice bearing HepG2 cell-derived tumors. Expression of the therapeutic genes by the transduced tumor cells was analyzed by RT-PCR and Western blotting., Results: We confirmed that Ad-ETK had antitumorigenic effects on human hepatocellular carcinoma (HCC) both in vitro and in vivo, and the TK/GCV system enhanced oncolytic adenoviral therapy. We confirmed that both E1A and HSV-TK genes were expressed in vivo., Conclusion: The Ad-ETK construct should provide a relatively safe and selective approach to killing cancer cells and should be investigated as an adjuvant therapy for hepatocellular carcinoma.