bluuebunny/crossref_metadata_2025_split huggingface dataset:
Acute stress show great influences on liver function and the expression of hepatic genes associated with lipid metabolism in rats
Authors: Gao Xiaoling , Zeng Yuaner , Liu Shuqiang , Wang Shuling 
Published: July 2013

Abstract

Background
The theory of Chinese medicine believes rage harms normal liver function, namely ’raged impairing liver' in short. The purpose of this study is to investigate the impact of acute stress on liver lipid metabolism in rats.

Methods and results
Comparison of liver function indicators, serum lipid level of rats under acute stress and normal rats, as well as detection of liver tissue in the SR - BI, ABCG5 and ABCG8 protein and gene expression changes. Acute stressed rats had shown a lower serum levels of albumin (P<0.01), HDL- cholesterol (P<0.01) than normal rats, with higher serum levels of globulin (P<0.01) and LDL-cholesterol (P<0.05). Acute stressed rat’s liver tissue exhibited a lower protein expression of ABCG5 (P<0.05), ABCG8 (P<0.01) and a higher level of SR-BI (P<0.05), compared with to normal rats. Furthermore, liver gene expression of ABCG5 (P<0.01) and ABCG8 (P<0.05) were lower in acute stressed rats than in normal rats, while SR-BI was higher in acute stressed rats than in normal rats (P<0.01).

Conclusions
Acute stress had a direct influence on rat’s liver lipid metabolism.
Neuropilin2 regulates the guidance of post-crossing spinal commissural axons in a subtype-specific manner
Authors: Tran Tracy S , Carlin Edward , Lin Ruihe , Martinez Edward , Johnson Jane E , Kaprielian Zaven 
Published: July 2013

Abstract

Background
Spinal commissural axons represent a model system for deciphering the molecular logic that regulates the guidance of midline-crossing axons in the developing central nervous system (CNS). Whether the same or specific sets of guidance signals control the navigation of molecularly distinct subtypes of these axons remains an open and largely unexplored question. Although it is well established that post-crossing commissural axons alter their responsiveness to midline-associated guidance cues, our understanding of the repulsive mechanisms that drive the post-crossing segments of these axons away from the midline and whether the underlying guidance systems operate in a commissural axon subtype-specific manner, remains fragmentary at best.

Results
Here, we utilize axonally targeted transgenic reporter mice to visualize genetically distinct dorsal interneuron (dI)1 and dI4 commissural axons and show that the repulsive class 3 semaphorin (Sema3) guidance receptor Neuropilin 2 (Npn2), is selectively expressed on the dI1 population and is required for the guidance of post-crossing dI1, but not dI4, axons. Consistent with these observations, the midline-associated Npn2 ligands, Sema3F and Sema3B, promote the collapse of dI1, but not dI4, axon-associated growth cones in vitro. We also identify, for the first time, a discrete GABAergic population of ventral commissural neurons/axons in the embryonic mouse spinal cord that expresses Npn2, and show that Npn2 is required for the proper guidance of their post-crossing axons.

Conclusions
Together, our findings indicate that Npn2 is selectively expressed in distinct populations of commissural neurons in both the dorsal and ventral spinal cord, and suggest that Sema3-Npn2 signaling regulates the guidance of post-crossing commissural axons in a population-specific manner.
Utility of a column-switching LC/MS/MS method in cytochrome P450 inhibition assays using human liver microsomes
Authors: Behera Dayanidhi , Pattem Rambabu , Kumar M. Siva Selva , Gudi Girish S. 
Published: July 2013

Abstract

Background: Liquid chromatography-tandem mass spectrometry (LC/MS/MS)-based in vitro cytochrome P450 (CYP) inhibition assays in pooled human liver microsomes using therapeutically relevant probe drugs are recommended by the US Food and Drug Administration to assess the potential for drug-drug interactions. As these assays are used routinely in pharmaceutical drug discovery screening of new chemical entities for drug interaction liabilities, there is a need to have higher analytical throughput. Column-switching methods may offer increased chromatographic throughput while maintaining the quality of data generated.

Methods: In this study, the CYP3A4 inhibition assay was used as a potential application to demonstrate the performance of a dual-column parallel chromatographic system in a column-switching mode. Testosterone 6β-hydroxylation was monitored and IC50 values of known CYP3A4 inhibitors were determined using conventional as well as column-switching LC/MS/MS methods.

Results: Mean IC50 values of ketoconazole, itraconazole and verapamil were 0.056, 0.061 and 23 μM (conventional method) compared to 0.05, 0.057 and 26 μM (column-switching method), respectively. The two different chromatographic methods resulted in IC50 values that were not statistically different and were within a twofold range, demonstrating reproducibility of results. Further, the column-switching method saved nearly 50% of analytical time in comparison to the conventional chromatographic method, indicating increased throughput leading to better utilization of mass spectrometer time without compromising the quality of data.

Conclusions: Similar column-switching methods may be used for other isoforms as well and offer a convenient increased analytical throughput in CYP inhibition assays.
Effects of Vascular Endothelial Growth Factor Signaling Inhibition on Human Erythropoiesis
Authors: Bhatta Sumita S. , Wroblewski Kristen E. , Agarwal Kelly L. , Sit Laura , Cohen Ezra E.W. , Seiwert Tanguy Y. , Karrison Theodore , Bakris George L. , Ratain Mark J. , Vokes Everett E. , Maitland Michael L. 
Published: July 2013

Abstract
Inhibition of vascular endothelial growth factor (VEGF) signaling increases red blood cell (RBC) counts, and erythropoiesis markers have been proposed to guide antiangiogenic therapy in humans. We analyzed RBC measurements in patients enrolled in three studies: a phase II trial of axitinib in thyroid cancer; a study of sorafenib in advanced solid tumors; and a randomized trial of fluorouracil, hydroxyurea, and radiation with and without bevacizumab for head and neck cancer. In the sorafenib trial, plasma erythropoietin concentrations were measured at baseline, day 8, and day 35. Over the first 84 days of treatment, RBC counts increased for each day on sorafenib (2.7 M/μL [95% confidence interval (CI), 1.5–3.9]) and axitinib (4.3 M/μL [95% CI, 2.2–6.5]). RBCs declined over the first 68 days of cytotoxic chemoradiotherapy alone (−12.8 M/μL per day [95% CI, −15.7 to −9.8]) but less so with added bevacizumab (−7.2 M/μL per day [95% CI, −9.5 to −4.9]). Erythropoietin levels increased, on average, by 9.5 mIU/mL between day 8 and day 35 of sorafenib exposure. No significant relationships between elevations in RBCs and changes in volume status or blood pressure or between elevations in erythropoietin and smoking status were found. VEGF signaling inhibition is associated with increased RBC and erythropoietin production in humans. The effects of these changes are subtle at physiologic doses and are unlikely to be clinically useful biomarkers for guiding the administration of or predicting treatment responses to VEGF pathway inhibitors.
Stakeholder Approach to Corporate Social Responsibility as a Rescipe for Peace in The Niger Delta
Authors: Lugard Sunday Bontur 
Published: July 2013

Abstract
Corporate Social Responsibility (CSR) is a pathway to business-stakeholders engagement in general and its host community in particular, especially when the operations of such enterprise have a way of negatively impacting the environment or other interests of such community. Empirical research has shown that such stakeholder engagement has a way of not just improving corporate-community relations but a strategic roadmap to corporate sustainability. This is one area International Oil Companies (IOCs) operating in Nigeria's Niger Delta region have without doubt neglected and floundered, and hence the ensuing and seemingly intractable confrontations from the host communities and militant groups who claim to be fighting the cause of such communities. The continuous hostilities and the consequent loss of production and stoppage of production is enough to make the IOCs seek for alternative ways of improving their engagement with the host communities; their conventional claim of not being local governments not having yielded the desired results. This piece offers an alternative that would engender peaceful, symbiotic engagement between the IOCs and their host communities through a stakeholder approach to CSR. This writer presents the concept of "emotional equity" as a strategic tool for community involvement in corporate sustainability.
Potential of Waterflooding in Shale Formations
Authors: Morsy Samiha , Sheng J. J. , Ezewu Roland O. 
Published: July 2013

Abstract
Waterflooding is the cheapest and most profitable secondary recovery method that has been used for more than seventy years for conventional oil reservoirs. However, few studies have been done on its viability on unconventional tight formations especially shales. The objective of this study is to investigate the potential of water imbibition in different shale formations. In this study, fresh water, water with different salinities, and high pH alkaline solutions were examined to recover oil from different shale formations. Reservoir core samples from Eagle Ford and outcrop samples from Mancos, Barnett, and Marcellus shales were used in this study. The samples were 2.54 to 3.81 cm in diameter and 0.762 to 5.08 cm in length. First, we studied the porosity of samples using helium porosimeter, weight difference, and CT Scanning. The average porosity was 3.4% for Mancos, 2% for Eagle Ford, 2.6% for Marcellus, and 7.7% for Barnett shale samples. Second, we studied the rock stability and spontaneous imbibtion of the different used samples in fresh water, different saline solutions (5–15 eq wt% of NaCl and KCl), and high pH alkaline solutions (0.1–2 wt% NaOH). During the spontaneous imbibition, the maximum oil recovery was 59% for Mancos using fresh water, 44% for Eagle Ford using 2 wt% NaOH and fresh water, 24% for Barnett using fresh water, and 4% for Marcellus using 2 wt% NaOH and 2 eq wt% of KCl. The Mancos shale samples were very sensitive to low water salinity (0–15 eq wt %) compared with the other shales. The higher oil recoveries of Mancos samples were positively correlated with clay swelling in fresh water and low saline solutions. Eagle Ford recovered more oil when exposed to NaOH solutions due to favorable mineral dissolution without affecting the cores' stability. On the other hand, Barnett was partially damaged when exposed to higher alkaline solutions (2 wt% NaOH) and Marcellus was very tight to allow any fluid imbibition. Collectively, our study showed a great potential of waterflooding in unconventional shale reservoirs.
Implications of US and Europe Shale Gas on the Nigerian Gas Market
Authors: Oyekunle A. A. 
Published: July 2013

Abstract
In the past few years, the US in order to reduce her dependence on foreign energy had ramped up efforts towards the discoveries of new conventional and unconventional sources of energy. One of such breakthroughs is the discovery of vast deposit of shale gas. A 2011 study estimates the US shale gas deposit at 2, 170 TCF1.
Encouraged by the success of the US, some European Nations are already prospecting for possible shale gas deposits in commercial quantity.
These has some implications for the Nigerian Gas whose major markets are in the US and Europe. This paper intends to look at the near term and long term effect of the shale gas revolution in the US and Europe on the Nigerian gas and options for the Nigerian gas in order to guarantee its demand.
Risk Based Deterministic Approach for Estimating Recoverable Volumes for Further Field Development Wells
Authors: Ogbalor Cyril , Fasasi Roseline , Akpos Ebufegha 
Published: July 2013

Abstract
The process of estimating oil and gas recoveries for producing field continues throughout the life of the field. There is always uncertainty in making such estimates, the level of uncertainty is affected mainly by the Quantity and quality of the geological, engineering, and geophysical data, the magnitude of uncertainty however, decreases with time until the economic limit is reached and the ultimate recovery is realized.
Experimental (ED) design techniques are increasingly been adopted as a standard, to consistently combine the uncertain parameters to construct a range of reservoir models to evaluate recoverable volumes. However, ED technology is a time and resource consuming workflow, requiring a suite of static and dynamic models to be generated and a full history matching process to be applied, however, when a project team is time constrained full ED approach, should be limited to only those reservoirs which have a maturity less than 70% and capture 90% of the impact to total remaining recoverable volumes.
Traditional deterministic simulation methods, calculate ultimate recovery based on the assumption that all input parameters are exactly known, however they sometimes ignore the variability and uncertainty in the input data which creates inherent problems resulting in over pessimistic or optimistic numbers.
This paper details Modelling strategy aimed at achieving a risked based and scalable solution to delivering realistic recoverable volumes for the candidate reservoirs in the planned time frame.
Introduction
Oil and gas volumes evaluation is achievable through any of the following methods: volumetric based on analogues, Performance based Decline curve Analysis, Material balance and Simulation (deterministic or probabilistic).
In the early stages of development of a reservoir, recoverable volumes estimates are restricted to and analogy and volumetric calculations.
The volumetric method, involves determining the areal extent of the reservoir, the rock pore volume, and the fluid content within the pore volume. This provides an estimate of the amount of hydrocarbons-initially-in-place. A recovery factor estimated using analogues is then applied to obtain the recoverable volumes. The analogue technique involves identifying a mature reservoir with similar structural and geological setting as the subject reservoir. The drainage radius and recovery factor from this mature analogue reservoir is then used to calculate recoverable volumes for the relatively greener subject reservoir.
Twenty Years of Horizontal Sandface Completion in SPDC
Authors: Nnanna Erasmus , Nwabueze Vincent , Kooijman Arjen 
Published: July 2013

Abstract
Horizontal drilling technology is a fairly mature technology. Advances in drilling tools and techniques have simplified the technology making it a common concept in field development projects both in green and brown fields. The objective of sandface completion in horizontal wells is to prevent collapse of the horizontal drainhole (borehole support and/or prevent sand production. The first objective applies to where the formation is relatively consolidated and therefore does not require sand-control. The second objective applies to friable formations with propensity for sand production.
Various sandface completion mechanisms have been deployed in SPDC horizontal wells. These include pre-drilled liners, slotted liners, openhole expandable sand screens, stand-alone screens and a combo of stand-alone screen, swellable packers and interval control devices (ICDs). With nearly 150 horizontal wells (including sidetracks and muti-laterals) drilled between 1992 and 2012, there has been a significant improvement in sandface completion philosophy mainly driven by the desire to achieve life-cycle sand exclusion. The earlier wells were completed with slotted liners while later applications have deployed stand-alone screens. Performance of these wells is constantly being reviewed for further optimization of the sandface completions where scope exists.
This paper traces the development of horizontal sandface completion in SPDC from the early days to present highlighting factors that led to improvements. It also explores the current trend in horizontal sandface completion, limitation of existing technology and scope for improvement.
Fiber Optic Based Pipeline Oil and Gas Leak and Intruder Detection System with Security Intervention Plan
Authors: Idachaba Francis , Wokoma Esther , Okuns Godwin , Brown Colin , Walker Ian 
Published: July 2013

Abstract
The accurate and timely localization of the vandalization and leak point on an oil pipeline provides operators with information to aid with the development of robust security response and intervention plans. These plans have the potential of reducing the impact of leaks on the environment by enabling operators to take actions to mitigate their effect. A major challenge with current leak and vandalization detection systems is the generation of spurious signals which in time slows down the response to these alerts. This paper presents results of the field trial of a Fiber Optic Cable based Oil/Gas leak and intruder detection system. Oil and Gas leaks were simulated on a pipeline section buried in a swamp location with 1mm and 2mm Orifices located at the 0°, 90° and 180° positions on the pipe with a section of the pipe exposed for third party intruder detection tests. The orifices were connected to compressed air and water used in place of Oil and gas. The fiber optic cable was buried on both sides of the pipeline and hooked up to the Helios Integrator. The system was able to detect and localize leaks from the orifices with the signal intensity proportional to the leak intensity. It was able to detect third party activities such as cutting and the use of hammers on the pipeline and also walking near the pipeline. The results coupled with the security intervention plan which is developed to provide varying levels of response will eliminate response to spurious signals thus providing a robust response and intervention plan to oil and gas leak and intruder detection.
AKPO and USAN Deepwater Field Operations (The First 100 Days): The Story and Lessons Learnt
Authors: Iwegbu M. , Yuba R. , Ani B. , Ekpecham O. 
Published: July 2013

Abstract
The startup / ramp up phase of an FPSO in an Offshore Deep Water environment characterized by simultaneous operations such as drilling, construction and commissioning activities with their attendant impact on production operations present several challenges.
An analysis of the first 100 days experience of the Akpo & Usan Deep Water Field Operations tells the story: A review of Shutdown occcurrences with their frequency, duration, classification, impact on production and root causes have provided viable data and essential details to help establish problem areas to be given adequate attention if seamless start-up of production is to be achieved.
The result of the analysis provides a bright pointer not only to the root causes of such shutdowns but underscores the learning curve required as feedback and recommendation to new assets in operations and future projects.
Effect of Viscosity of Alkaline/Surfactant/Polymer on Enhanced Oil Recovery in Heterogeneous Sands
Authors: Ojo Oladimeji V. , Onyekonwu M. O. , Ogolo N. A. , Ubani C. 
Published: July 2013

Abstract
New development in technology and the rise in world oil prices give promises that substantial portion of otherwise neglected oil can be recovered. Reservoir heterogeneity significantly affects both the oil production and the performance of injection wells in water flooding or miscible flooding projects, thus the influence of heterogeneity on the oil exploitation process has been a concern in petroleum engineering. Numerous laboratory experimental studies and field tests on Alkaline/Surfactant/Polymer (ASP) flooding have been done. In this research, the relationship between the viscosity of an ASP solution and oil recovery in heterogeneous porous models were studied. Twenty-four ASP flood tests were conducted using artificial models. These models were made to have different permeability variation coefficients so that ASP floods in homogeneous and heterogeneous reservoir can be compared Local materials in place of industrial materials were used.
Four ASP solutions were prepared and used in the ASP flood tests. The effect on tertiary oil recovery as viscosity increased was investigated. For heterogeneous models, it was found that increasing the ASP viscosity from 1.00cp to about 2.56cp increased and improved oil recovery. Further increase in viscosity to about 3.6cp had no much effect on recovery, because increasing the alkaline concentration reduced the visco-elastic effect of the viscosity of the solution.
Investigating The Carrying Capacity And The Effect Of Drilling Cutting On Rheological Properties Of Jatropha Oil Based Mud
Authors: Fadairo Adesina , Orodu David , Falode Olugbenga 
Published: July 2013

Abstract
Environmental problems associated with complex fluids in general and diesel oil based mud in particular, are among the major concerns of world communities. Studies have shown that diesel oil based mud is highly environmentally unfriendly because of its deleterious effects on the environment and expensive to dispose. For these reasons, it is imperative to promote and propagate the use of environmentally friendly mud for drilling operation.
This study investigates the drilling cutting carrying capacity of both jatropha and diesel based drilling muds. It also examines the effect of contaminants on the rheological properties of the muds. The properties measured are Plastic Viscosity, Yield Point, Apparent Viscosity, Mud Weight, Gel strength.
The results obtained show that cuttings have detrimental effects on rheological properties of both muds by increase in filter cake thickness, loss circulation, struck pipe and operational cost, hence reduction in drilling efficiency. It also showed that Jatropha oil based mud exhibits better adaptability, higher carrying capacity and less pressure loss in pipe than diesel oil based mud, hence should be encouraged for use during drilling activities.
Finally, the results of the study would enable the drilling engineer to determine the hole cleaning capacities, at which percentage of cutting become catastrophic and the extent at which cutting should be allowed in the mud.
Pressure Behaviour in Partial Completion Wells for Closed Boundary System
Authors: Dankwa O. K. , Ofei T. N. , Nyame M. 
Published: July 2013

Abstract
A systematic and simplest analytical solution for obtaining pressure behavior of vertical wells with partial completion for no-flow boundary system is the main objective of this paper.
Depending upon the type of wellbore completion configuration, it is possible to have radial, spherical or hemispherical flow near the wellbore. A well with a limited perforated interval (partial completion) could result in spherical flow in the vicinity of the perforations. A well which only partially penetrates the pay zone, could result in hemispherical flow. These conditions could arise where coning of bottom water or gas cap becomes a serious issue
Partial completion is the completion of or flow from less than the entire producing interval. This situation causes a near-well flow constriction that result in a positive skin effect in a well-test analysis.
The partial differential equations were solved for no-flow boundary system in Laplace and Fourier Transform domains before inversion to real time domain.
The application of Gaver-Stehfest algorithm (1970) was used to invert the dimensionless pressure drop in Laplace space in a MATLAB program.
Pressure behaviour solution for closed boundary has been obtained, taking into consideration the effect of partial completion.
Various plots of pressure drop and derivative versus time for a well partially completed at the middle (centre) at different skin (S) values have also been obtained.