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Search Results: 1 - 10 of 331230 matches for " James J. Sheng "
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New Methods to Calculate Water Saturation in Shale and Tight Gas Reservoirs  [PDF]
Arash Kamari, James J. Sheng
Open Journal of Yangtze Oil and Gas (OJOGas) , 2018, DOI: 10.4236/ojogas.2018.33019
Abstract: The determination of water saturation is a key step for the reservoir characterization and prediction of future reservoir performance in terms of production. The importance of water saturation has been further identified when the reservoirs refer to rocks with low porosity and permeability such as shale and tight formations. In this communication, two advanced artificial intelligence strategies consisting of least square support vector machine (LSSVM) and gene expression programming (GEP) have been applied in order to develop reliable predictive models for the calculation of water saturation of shale and tight reservoirs. To this end, an extensive core and log data bank has been analysed from 12 wells of a Mesaverde group tight reservoir located in the largest Western US. The results indicate that the estimated water saturation data by the models developed in this study are in satisfactory agreement with the actual log data. Furthermore, new methods proposed in this study are useful for the characterization of shale and tight reservoirs and can be applied to the relevant software.
Chip Flood (vs) Core Flood—Assessment of Flowback and Oil Productivity in Oil-Wet Hydraulic Fractured Rocks  [PDF]
Srikanth Tangirala, James J. Sheng, Jiawei Tu
Open Journal of Yangtze Oil and Gas (OJOGas) , 2019, DOI: 10.4236/ojogas.2019.41005
Abstract: New developments in lab technologies help us to explore problems that were less understood in the past due to the limitations and technological constraints. One such problem of assessing the formation damage created by the invasion of fracture fluid into the matrix at lab scale is the visualization of fluid saturation distributions inside the matrix. According to the current understanding, the high capillarity contrast between the fracture and the matrix creates a non-uniform saturation distribution of invaded fluid phase during flowback, with the saturations mostly concentrated at the fracture face. With the advent of microfluidics, their application has become more feasible to visually analyze the effectiveness of surfactants to mitigate the invasion-created formation damage and understand the impact of depth of invasion on the characteristics of flowback and oil productivity. Through our previous work, we have successfully demonstrated the capability of this new visualization tool in studying the factors of the presence of surfactant in the fracture fluid and its depth of invasion, to understand the flowback efficiencies and later oil productivities in oil-wet fractured formations. Since the substrate for flooding was a proxy model of an actual rock, the chip flooding results need to be validated with conventional core flooding experiments. In contemporary times, when the new advancements in technology are driving the research progress in all industries, it is mandatory to take a well informed decision by imposing a comparative check on the results with accessible conventional means, wherever possible. The success of validation of chip flooding approach with the core flooding approach in this work instates a strong belief over the application of microfluidics to pursue more research in related fields of oil recovery.
Effects of Invasion of Water with and without Surfactant on the Oil Production and Flowback through an Oil Wet Matrix—A Microfluidic Chip Based Study  [PDF]
Srikanth Tangirala, James Sheng
Open Journal of Yangtze Oil and Gas (OJOGas) , 2018, DOI: 10.4236/ojogas.2018.34024
Abstract: The invasion of hydraulic fracturing fluids into the matrix through a relatively conductive fracture network causes capillary entrapment of the fluids that lead to the reduction of relative permeability of oil during production. Such a formation damage could be alleviated by the use of surfactants, however, their use does not always guarantee an efficient oil recovery. Through a microfluidic-chip based experimental study, the present work highlights the factors that control the later oil productivity and flowback especially through an oil-wetting matrix. The results from this study indicate that for an oil-wet formation, at shallow invasions, a water-based fracture fluid gives higher later oil production rates than a moderate IFT-reducing surfactant, and at deep invasions, the latter fluid gives better later oil production rates than the former. These results are very useful to the oil industry in making well informed decisions for selecting appropriate fracture fluids to stimulate oil-wet formations.
Gene functional similarity search tool (GFSST)
Peisen Zhang, Jinghui Zhang, Huitao Sheng, James J Russo, Brian Osborne, Kenneth Buetow
BMC Bioinformatics , 2006, DOI: 10.1186/1471-2105-7-135
Abstract: By using a statistical model to measure the functional similarity of genes based on the Gene Ontology directed acyclic graph, we developed a novel Gene Functional Similarity Search Tool (GFSST) to identify genes with related functions from annotated proteome databases. This search engine lets users design their search targets by gene functions.An implementation of GFSST which works on the UniProt (Universal Protein Resource) for the human and mouse proteomes is available at GFSST Web Server. GFSST provides functions not only for similar gene retrieval but also for gene search by one or more GO terms. This represents a powerful new approach for selecting similar genes and gene products from proteome databases according to their functions.Cellular function in a biological system normally involves participation and interaction of multiple genes. Mutations that alter function of any one of these genes can potentially increase disease susceptibility. For example, the tumor suppressor gene BRCA1 suppresses cell growth and participates in transcription-coupled DNA damage repair. Mutations in BRCA1 increase the risk of early onset breast cancer as well as ovarian and prostate cancer [[1,2], and [3]]. Genes with functions similar to BRCA1 can be considered additional candidate genetic risk factors for breast, ovarian, prostate, or other cancers.One common approach to identify functionally similar genes is to find genes that share significant sequence homology. However, functional similarity does not always require sequence similarity. For example, both P53 [4] and BRCA1 [5] function as tumor suppressor genes. Similar to BRCA1, mutations in P53 have also been found in breast cancer patients [6]. The two genes share no sequence homology. As a result, a sequence similarity search tool, such as BLAST [7], is unable to reveal their functional similarity.An alternative to sequence homology search is key word search, but this approach has two weaknesses. First, key words for gene f
Reactive oxygen species drive herpes simplex virus (HSV)-1-induced proinflammatory cytokine production by murine microglia
Shuxian Hu, Wen S Sheng, Scott J Schachtele, James R Lokensgard
Journal of Neuroinflammation , 2011, DOI: 10.1186/1742-2094-8-123
Abstract: Oxidation of 2', 7'-dichlorodihydrofluorescin diacetate (H2DCFDA) was used to measure production of intracellular ROS in microglial cell cultures following viral infection. Virus-induced cytokine and chemokine mRNA and protein levels were assessed using real-time RT-PCR and ELISA, respectively. Virus-induced phosphorylation of microglial p38 and p44/42 (ERK1/2) MAPKs was visualized using Western Blot, and levels of phospho-p38 were quantified using Fast Activated Cell-based ELISA (FACE assay). Diphenyleneiodonium (DPI) and apocynin (APO), inhibitors of NADPH oxidases, were used to investigate the role of virus-induced ROS in MAPK activation and cytokine, as well as chemokine, production.Levels of intracellular ROS were found to be highly elevated in primary murine microglial cells following infection with HSV and the majority of this virus-induced ROS was blocked following DPI and APO treatment. Correspondingly, inhibition of NADPH oxidase also decreased virus-induced proinflammatory cytokine and chemokine production. In addition, microglial p38 and p44/42 MAPKs were found to be phosphorylated in response to viral infection and this activation was also blocked by inhibitors of NADPH oxidase. Finally, inhibition of either of these ROS-induced signaling pathways suppressed cytokine (TNF-α and IL-1β) production, while chemokine (CCL2 and CXCL10) induction pathways were sensitive to inhibition of p38, but not ERK1/2 MAPK.Data presented herein demonstrate that HSV infection induces proinflammatory responses in microglia through NADPH oxidase-dependent ROS and the activation of MAPKs.Microglia, like other phagocytic cells, generate reactive oxygen species (ROS) as a mechanism to eliminate invading pathogens. Oxygen-containing free radicals such as superoxide (O2-), the hydroxyl radical (.OH), and hydrogen peroxide (H2O2) are highly reactive. ROS production by microglial cells, while beneficial in clearing invading pathogens from the brain, may also induce irreparable harm
Moderation of Fatigue and Stress in the Carry-over of Self-Regulation and Self-Efficacy for Exercise to Self-Regulation and Self-Efficacy for Managed Eating  [PDF]
James J. Annesi
Psychology (PSYCH) , 2011, DOI: 10.4236/psych.2011.27106
Abstract: Behavioral treatments for morbid obesity have not been effective, possibly because of a poor understanding of the relations of psychosocial factors and exercise and eating behaviors. Recent research suggests that exercise program-induced improvements in self-efficacy and self-regulatory skills use may carry-over to self-efficacy and self-regulation for controlled eating. However, for individuals with morbid obesity, fatigue and anxiety may moderate these relationships. The purpose of this research was to evaluate this moderation. Adults with Grade 3 obesity (MBMI = 46.0 kg/m2) participated in 26 weeks of cognitive-behaviorally supported exercise paired with 12 weeks of either nutrition education (n = 95) or a cognitive-behavioral nutrition component (n = 109). There were significant improvements in self-regulation and self-efficacy for exercise, and self-regulation and self-efficacy for controlled eating, which did not differ by treatment condition. Bivariate relationships between changes in self-regulation for exercise and self-regulation for controlled eating (β = .63), and changes in exercise self-efficacy and self-efficacy for controlled eating (β = .51), were strong. Moderation of these relationships by fatigue and anxiety was either significant or marginally significant (ps < .01 and ps < .08, respectively). Both changes in self-regulation for controlled eating and self-efficacy for controlled eating significantly contributed to the explained variance in BMI change (R2 = .30). Implications of the findings for behavioral weight-loss treatment for those with morbid obesity were discussed.
Activation of AMPK by Bitter Melon Triterpenoids Involves CaMKKβ
Tristan J. Iseli, Nigel Turner, Xiao-Yi Zeng, Gregory J. Cooney, Edward W. Kraegen, Sheng Yao, Yang Ye, David E. James, Ji-Ming Ye
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0062309
Abstract: We recently showed that bitter melon-derived triterpenoids (BMTs) activate AMPK and increase GLUT4 translocation to the plasma membrane in vitro, and improve glucose disposal in insulin resistant models in vivo. Here we interrogated the mechanism by which these novel compounds activate AMPK, a leading anti-diabetic drug target. BMTs did not activate AMPK directly in an allosteric manner as AMP or the Abbott compound (A-769662) does, nor did they activate AMPK by inhibiting cellular respiration like many commonly used anti-diabetic medications. BMTs increased AMPK activity in both L6 myotubes and LKB1-deficient HeLa cells by 20–35%. Incubation with the CaMKKβ inhibitor, STO-609, completely attenuated this effect suggesting a key role for CaMKKβ in this activation. Incubation of L6 myotubes with the calcium chelator EGTA-AM did not alter this activation suggesting that the BMT-dependent activation was Ca2+-independent. We therefore propose that CaMKKβ is a key upstream kinase for BMT-induced activation of AMPK.
Root Canals and Crowns: An Analysis of the Spatial Distribution of Dental Offices in Ciudad Juárez, Chihuahua, Mexico, 1996-2011  [PDF]
Patricia J. Boda, James Harris
International Journal of Geosciences (IJG) , 2013, DOI: 10.4236/ijg.2013.46A2005

Every city above a certain size has health services that are located, to a large extent, close to their patients. This study analyzes the spatial distribution of dental office and the change in the number of dental offices in Ciudad Juárez, Chihuahua, Mexico over a 15-year time period. Research was conducted in 1996 and 2011. Maps showing the location of dental offices for these two years indicate a clustering of dental offices within one and one-half miles of the city’s two principal border-crossing points between the United States and Mexico. Provider-based surveys were also used to determine the mix of patients (US or Mexican citizens) at the dental offices found throughout the city. By 2011, nearly all of the dental offices clustered within one and one-half miles of the two principal US-Mexico border crossings had 100% of their patients from the United States.

Precision Microwave Electrodynamic Measurements of K- and Co-doped BaFe$_2$As$_2$
J. S. Bobowski,J. C. Baglo,James Day,P. Dosanjh,Rinat Ofer,B. J. Ramshaw,Ruixing Liang,D. A. Bonn,W. N. Hardy,Huiqian Luo,Zhao-Sheng Wang,Lei Fang,Hai-Hu Wen
Physics , 2010, DOI: 10.1103/PhysRevB.82.094520
Abstract: We have studied the microwave electrodynamics of single crystal iron-based superconductors Ba$_{0.72}$K$_{0.28}$Fe$_2$As$_2$ (hole-doped, $T_\mathrm{c}$ $\approx $30 K) and Ba(Fe$_{0.95}$Co$_{0.05}$)$_2$As$_2$ (electron-doped, $T_\mathrm{c}$ $\approx$20 K), by cavity perturbation and broadband spectroscopy. SQUID magnetometry was used to confirm the quality and homogeneity of the samples under study. Through cavity perturbation techniques, the temperature dependence of the in-plane London penetration depth $\Delta\lambda(T)$, and therefore the superfluid phase stiffness $\lambda^2(0)/\lambda^2(T)$ was measured. Down to 0.4 K, the data do not show the exponential saturation at low temperatures expected from a singly-, fully-gapped superconductor. Rather, both the electron- and the hole-doped systems seem to be best described by a power law behavior, with $\lambda^2(0)/\lambda^2(T)$ $\sim$ $T^n$ and \emph{n} $\approx$ 2.5. In the three samples we studied, a weak feature near the sensitivity limit of our measurements appears near $T/T_\mathrm{c}$ =~0.04, hinting at a corresponding low energy feature in the superconducting density of states. The data can also be relatively well-described by a simple two-gap s-wave model of the order parameter, but this yields parameters which seem unrealistic and dependent on the fit range. Broadband surface resistance measurements reveal a sample dependent residual loss whose origin is unclear. The data from the \FeAs samples can be made to scale as $\omega^2$ if the extrinsic loss is treated as an additive component, indicating large scattering rates. Finally, the temperature dependence of the surface resistance at 13 GHz obeys a power law very similar to those observed for $\Delta\lambda(T)$.
Clinical, Pathological and Surgical Risk Factors Associated with Craniopharyngioma Recurrence: A Literature Review  [PDF]
James Lubuulwa, Zhuang Miao, Shengwen Liu, Juan Chen, Sheng Wang, Wei Jiang, Kai Shu, Ting Lei
Open Journal of Modern Neurosurgery (OJMN) , 2019, DOI: 10.4236/ojmn.2019.91008
Abstract: Objective: This review article attempts to examine and provide an overview of the risk factors associated with craniopharyngioma recurrence. Methods: A literature review of articles relating to the recurrences of craniopharyngioma and the clinical, molecular prognostic indicators of recurrence and treatment outcomes was performed retrospectively. Results: A total of 107 studies which described specific risk factors related to craniopharyngioma recurrence were identified which included but not limited to 54 retrospective case series, 7 systematic reviews, 21 laboratory reports, 13 case reports and 12 literature reviews. Conclusion: Based on the evidence identified in this review, the risk factors for recurrence in craniopharyngioma management are interrelated in a complex way, and surgery with or without adjuvant radiotherapy is reported to be of long-term benefit, but a disparity in findings suggests no definitive consensus on the risk factors of craniopharyngioma recurrence. More high-quality research is needed.
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