bluuebunny/crossref_metadata_2025 huggingface dataset:
i-field™ Programs Enable Operational Excellence in a Challenging Environment; Pushing the Limits of Large Data Transfer for Real Time Monitoring and Surveillance Operations in San Joaquin Valley
Authors: Popa Andrei , Barrett Mark , Cassidy Steve
Published: September 2011

Chevron's San Joaquin Valley (SJV) Business Unit (BU) is a mature, heavy oil, thermally enhanced asset consisting of large fields that have been producing for over a century. To ensure continuing technology transformation, in 2003 San Joaquin Valley started its own i-field program being among the first BUs to pursue Chevron's enterprise-wide effort in building the Digital Oil Field of the Future. From its initiation, the program has been focusing on creating solutions to manage and optimize operations and enhance recovery.

The paper showcases one of the most technologically advanced i-field heavy oil solutions implemented in San Joaquin Valley thermal assets, involving a high accuracy tiltmeter program implemented by a partner service company to advance the understanding of diatomite operations and monitor the surface ground movement

In 2008, Chevron's SJV i-field team partnered with its Information Technology (IT) department to develop a state-of-the-art application called Integrated Diatomite Operations Tool (i-DOT). The product incorporated current field workflows for mapping the grid deformation with business data (well locations and status, steam volumes and dates, etc.) in relevant time. This was accomplished by establishing a live connection between Chevron and partner service company servers whereby terabytes of grid data would flow seamlessly into Chevron's SJV servers. Data acquisition, data processing and storage efforts were accomplished through an integrated effort between IT, GIS and PetroWeb development teams. Workflows were built through close collaboration between i-field engineers, petroleum engineers, earth ecientists, IT professionals and the operations group.

The i-DOT solution has become the single point of operation monitoring and activity scheduling for multiple groups such as Operations, Asset Development and the Drilling team. The benefits of implementing i-DOT solutions are significant and transformed our decision making process in diatomite fields. The paper includes not only value creation but also lessons learned during development, deployment and end-user acceptance.
Implementing i-field™ Integrated Solutions for Reservoir Management: San Joaquin Valley Case Study
Authors: Popa Andrei , Horner Katie , Cassidy Steve , Opsal Steve
Published: September 2011

To achieve more efficient business processes by exploiting data and knowledge management, real-time systems and advanced analytical tools, most major integrated and service companies have developed, or are in the process of developing, intelligent programs also known as Digital Oil Field of the Future3. The i-field™ program represents Chevron's efforts to integrate people, processes, technology and information to achieve its vision of Upstream Transformation. Ultimately, this vision translates to higher-quality decision making and changes the way we operate our assets.

A new multiyear i-field™ program, Integrated Reservoir Management (i-RM), was initiated in the San Joaquin Valley to enable efficient reservoir management (RM) and quality decision making for heavy oil assests operating under steamflood EOR technologies.

The paper describes the journey undertaken by the project team to build a proprietary steamflood integrated reservoir management tool that answers the basic neverending engineering requirements: instant access to clean data, single source of information for everyone and seamless data-tools linkage. The ultimate benefit is not only increased time spent by engineers and earth scientists to analyze data but also consistent project design workflows and decision making processes across fields. In addition to above documented benefits, the manuscript includes operator's experience with project framing, development, deployment and user-acceptance.
Taking Vital Signs of Remote Monitoring Systems
Authors: Mikulis M. , Meldrum E.
Published: September 2011

An operator recently completed more than 20 intelligent well systems, with extensive permanent in-well monitoring throughout. As part of this program, a new capability is being included to monitor and provide early warning regarding the health of the data collection system. The objective of the health monitoring system is to give greater insight into the quality of the data being collected. By analogy, instead of getting a pulse from the system, the operator receives actual diagnostics about any urgent issues. The tool's dashboard displays a visual indication of the integrity and quality of all the down-hole equipment data being recorded in the historian and allows a technician to quickly drill down to the source of the anomaly.

The system provides the following benefits: Early detection of impending equipment failuresTechnical support staff are warned about alarming events and trendsTechnical support staff are provided a tool to quickly analyze equipment performance by summarizing the current status and recent quality of acquired dataFaster response by technical resources to events, and quicker resolution of down-hole equipment problemsEasy detection of misconfigured tags in the OSISoft PI historian that could mitigate future data management issues or missing critical dataPrevents periods when no data is recorded; the event alarms immediately notify the person responsible rather than relying on periodic system checks, e.g., once a month
Will Performance Based Safety Processes Prevent Future Oil Spill Disasters?
Authors: Miller Chuck
Published: September 2011

Now that the authorities have taken the infamous Deepwater Horizon BOP to the surface for inspection, the post mortem debate on the causes of the largest accidental marine oil spill in the history of the petroleum industry has begun. While a wide variety of experts are considering next steps to prevent this type of breakdown in the future, safety and reliability engineers are debating the basic premise; "Was the root cause of the Macondo incident a procedural problem or was this simply a series of failures that could not have been imagined prior to the incident?

Analysis revealed that the BOP "operated as designed" however some reports suggest that the incident may have avoided by considering the following:

What could have been done to predict this event? Would the employment of HAZOP principles have identified the potential failure? Was the Deepwater Horizon BOP properly sized, installed and tested? Would continuous on-line diagnostic testing of the BOP revealed a faulted state? Would the use of a performance based design specification provide a better safeguard design than the prescriptive API 16D?
Evaluation of Orientated Perforating in the Buzzard Field
Authors: Mobasheri Mohammad , Durham Craig , White Martin
Published: September 2011

Orientated perforating is used to orientate the perforation tunnel parallel to the highest in-situ stress plane in order to reduce and/or delay sand failure. The technique is most effective in high angle and horizontal wells, so early Buzzard wells were perforated with conventional 60° phasing. Orientated perforating was subsequently adopted on Buzzard after log derived sand strengths were generally weaker than prognosed. The following paper presents the results of a review of six months sand production data from 21 production wells, in an attempt to correlate sand production with perforation orientation.

Due to inherent inaccuracy in allocating sand production to individual wells, wells were categorized as high, medium or low sand producers and various parameters such as hole inclination, azimuth, and UCS rock strength were considered to establish correlations between perforation orientation and sand production, all of which were inconclusive other than a slight correlation showing increasing sand potential with hole inclination. As all wells are sub-horizontal and the sand strength is marginal for a passive sand control techniques, it is concluded that orientated perforation does not give any measurable reduction in sand production from Buzzard wells.

The effect of perforation orientation on liner erosion was reviewed using Computational Fluid Dynamic models of a nominal 100ft 5.1/2" liner section. This showed no significant difference between 10–350° and 60° phasing perforation, instead wellbore inclination, flow rate and sand particle size increase the potential erosion rate in some wells.
Forties Infill Drilling Eight Years on; Continued Success Through the Application of Thorough Development Geoscience Driven by 4D Seismic
Authors: Rose Philip , Barker Gregg , Koster Klaas , Pyle Jeff
Published: September 2011

In the eight years since Apache purchased the Forties Field from BP over 100 infield targets have been drilled with an overall success rate of 74%. As a result of this infill drilling campaign the field production rate has been held at a plateau rate of 60,000 bopd despite an average rate of 41,000 bopd in 2003, the year of purchase from BP. Indeed the success of this campaign has resulted in a shortage of sidetrack donor wells so there has been a return to surface drilling on all five platforms. Furthermore, to enable the full exploitation of the forward target portfolio Apache is installing a new 18 slot platform, the Forties Alpha Satellite Platform (FASP) in 2012.

Key to Apache's success on Forties has been a constant drive to push the boundaries of 4D seismic interpretation and lithology prediction from seismic and the ability to integrate this information with local production and well data. In this paper case histories are presented to illustrate our approach to target generation and the evolution of target generation over time is evaluated.

The above methodology has led to many convincing successes over the years. The acquisition of a new 4D seismic volume in 2010 has resulted in a significant boost to our drilling results, allowing us to have our most productive drilling 6 months to date, including one well with an initial production rate of 12,000 bopd, the highest initial rate recorded in the field since 1992.
Innovative Mono-Column Support Structure
Authors: MacLeod Donald , Mathie Tom , Dunlop Graham , Duvall Sean
Published: September 2011

To facilitate a new compression package on an already crowded offshore platform, a new 2,000 tonne module is to be installed on top of a unique mono-column support. Equivalent to the height of the London Eye, the 140 metre high, 4.5 metre diameter mono-column sits in 136 metres of water, a depth much great than any similar structure. Although a simple structure, this is the first of its kind in the North Sea and possibly unique worldwide.

The new mono-column is supported directly on the existing jacket pile at the sea bed and uses the platform's existing redundant pile capacity to economically extend the space available for the new compression facilities. A simple spigot interface between the mono-column and existing pile also negates the need for grouting, temporary fixings and any subsea intervention. Traditional approaches to increasing real estate on offshore platforms involve the installation of cantilevers or shoe horning equipment into inefficient spaces leading to extensive offshore hours and lengthy shutdowns. The critical design consideration for this structure is its ability to survive a ship impact scenario. To address this, the structure adopts technology developed for the transport of nuclear materials. Energy absorbing technology and analysis expertise have been utilised to create a ‘crumple zone’ to protect the new structure.

Due to its simplicity, this innovative concept has resulted in considerable commercial benefits which include:

Reduced shutdown duration. A conventional approach would require around a 3 week shutdown. At approximately £2 million per day deferred/lost revenue, this is a saving of £42 million for a major offshore production platform. Eliminated Flotel requirements. Conventional approaches would require approximately 60 days of Flotel hire at a total cost of £12 million. Against a mono-column installed cost of £8 million, a saving of £46 million has been achieved.
A Low Tech, Low Risk System for the Installation of Large Structures in Deep Water
Authors: Joensen Arnbjorn , Paul David
Published: September 2011

The paper describes a novel system for the transportation and installation of subsea structures without the need for an HLV. The method is applicable to structures weighing from a hundred tonnes to several thousand tonnes in water depths of 100m -3000m and is particularly well suited to hostile environments. It enables even the smallest crane vessels to install large structures and increases the development options for marginal fields in remote locations.

The structure is fully submerged throughout the tow and installation phases and consequently the surface weather conditions have little impact on the tow or lowering operations. The reduced weather sensitivity increases the operating window for hostile regions, offering greater schedule flexibility.

All the individual aspects of the system are derived from very basic principles, existing technology and low cost components but the combination has resulted in a potential "game changer" for the development, installation and decommissioning of subsea structures.
Practical Surveillance Analysis on Thermal Heavy Oil Projects: Integrating Seismic Data with Production Case Studies
Authors: Baker Richard , Sandhu Kerry , Lifshits Gary
Published: September 2011

Enhanced oil recovery methods for heavy oil are growing at a fast pace. In Canada alone, approximately 53% of the nation's crude oil production (~2.8 MMBbl/day) comes from Alberta's Oil Sands. Remote sensing and monitoring technologies developed for thermal methods are providing the industry with an immense amount of data that will aid in the improvement and optimization of production performance. This paper details how to integrate seismic, tiltmeter, temperature observation well data with field production data, first with simple surveillance techniques, then with flow simulation.

Currently, heavy oil is experiencing significant growth in reserves whereas conventional light oil reserves are essentially fully tapped and are diminishing: heavy oil is becoming key to meeting growing energy demands worldwide. Current analytical approaches to heavy oil reservoir studies are too general, and tend to not include rich surveillance data such as seismic, temperature and pressure. This general approach over-simplifies the dynamics present in these reservoirs and does not give an accurate depiction of behavior and performance estimation. On the other hand large simulation studies can be cumbersome and not adaptive to new surveillance data. This paper focuses on a hybrid approach to analyzing various heavy oil fields in Canada, and outlines newly developed surveillance methods which better characterize heavy oil reservoirs. These field cases include geological data, pressure readings, seismic analysis, temperature observations, and historical production, all of which are used to enable the optimization of field production.

The proposed analytical techniques allow for a more precise estimate of recovery and sweep efficiency so that an efficient optimization strategy can be developed. Applying these analytical techniques to the Surmont and Christina Lake projects in the Athabasca area has given particularly important insight into SAGD steam chamber development and has shown to accurately estimate steam chamber volume and shape.
KP4: Ageing & Life Extension Inspection Programme - The First Year
Authors: Stacey Alexander
Published: September 2011

With a significant proportion of the UK's offshore infrastructure having exceeded the original design life, the ageing population of offshore installations presents a constant and growing challenge to safety. Ageing is characterised by deterioration which, in the severe operational environment offshore, can have serious consequences for asset integrity if not managed properly.

The Health and Safety Executive's Ageing and Life Extension Inspection Programme, also known as Key Programme 4 (KP4), was launched in July 2010 to the UK offshore industry. The purpose of KP4 is to:

determine whether the risks to asset integrity associated with ageing and life extension are being controlled effectively; raise awareness of the need for specific consideration of ageing issues as a distinct activity within the asset integrity management process and of the need for senior management to demonstrate leadership on this matter; identify shortcomings in duty holder practices in the management of ageing and life extension and enforce an appropriate programme of remedial action; work with the offshore industry to develop a ‘best practice’ common approach to the management of ageing installations and life extension.

The first year of KP4 entailed a programme of eight duty holder onshore and offshore inspections, covering a wide spectrum of topic areas, including organisational factors, structural integrity, materials (including corrosion), maritime integrity, mechanical integrity, process plant integrity, fire and explosion integrity, electrical and control systems integrity, wells and offshore pipelines. This paper presents a general overview of KP4 and a summary of progress made and initial findings in the first year of KP4.
Deployment of the Reelwell Drilling Method in a Shale Gas Field in Canada
Authors: Belarde Miguel , Vestavik Ola
Published: September 2011

The Reelwell Drilling Method (RDM) is a multi-purpose system incorporating a unique flow arrangement. It employs conventional drillpipe into which is fitted an inner string to form a concentric drill string. This arrangement allows the return fluid containing drill cuttings from the bottom of the well to be transported back through the inside of the drill string. The technique enables improved hole cleaning and improved downhole pressure control, and has unique features for application to managed pressure and extended reach drilling operations.

Development of the RDM started in 2004 and has since then been through several full scale tests. In the fall of 2010 it was deployed in a shale gas well in Canada. The main goal was to demonstrate the system in a live gas well and to gain field experience of the technology. The system was used in both the vertical and horizontal sections of the well. The concentric drill string was used for drilling the whole well in several bit runs, with circulation in both conventional and concentric circulation modes. The well was drilled to 4250 m MD in 8¾" hole size. The operation validated the concept and demonstrated a practical implementation on conventional drilling rigs. The operation is an important step in the evolution of a technology, which has a significant potential to improve operational efficiency and thereby the recovery of petroleum resources.
An Operating Management System to Deliver Safe Operations
Authors: Ferrow Michael
Published: September 2011

Although occupational safety metrics in the Oil and Gas Industry have continued on a downward trend for many years, major accidents have continued to occur around the world. Individual assets and operators will generally have no individual recent history of major accidents but must nevertheless learn from this overall body of major accidents and their precursors.

The immediate technical causes for these accidents are generally well understood and improvements can usually be implemented by everyone. There is however only limited value in trying to prevent just lookalike accidents. A study of a range of accidents over the last 100 years identifies common themes, particularly in the areas of proper assessment of risk, management of change and the basic control of work at the workface. To control these aspects properly, reliably and sustainably requires an overarching system of work control that is commensurate with the risks and consequences of more or less all activities in a business.

ConocoPhillips UK Upstream has carried out a thorough review and overhaul of management systems designed to fully comply with its own corporate standards and UK legislation. During this review the decision was made to create an Operating Management System to incorporate all necessary processes and controls to deliver a safe, high performing operation.

The features of the developed system are described along with insights that may help others contemplating assessment and overhaul of their own systems.
Fit For Purpose And Cost Effective Integrated Operations Implementation For Mature Assets In Maersk Oil North Sea UK Limited
Authors: Bjerregaard Claus G. , Ratcliffe Helen
Published: September 2011

Integrated Operation (IO) is often perceived as a long term, high cost commitment for an organisation. This perception often makes it difficult to gain the senior sponsorship required to get a programme off the ground for mature assets. This paper outlines how Maersk Oil North Sea UK Limited (Maersk Oil UK) designed and delivered a project, which generated real business value for mature assets within a short timeframe.

Key focus in the justification, design and implementation of the project, was the ability to deliver a solution that fitted the business needs and gave immediate value without compromising future opportunities. The project was designed and implemented as the first step towards and proof of the concept for Integration Operations solutions with focus on production optimisation and reservoir management within Maersk Oil UK.

The key business process focus was on well test automation, well and reservoir monitoring and production optimisation. All technologies used were readily available and only mature software solutions were used. Part of the required technology was already available in the company however without using the full potential.

The paper describes the approach to, and how senior business sponsorship was obtained and retained, how business needs were identified and addressed, how the technology requirements were satisfied and how this influenced the work flow and operation. The paper includes what made the project succeed and why some of the initiatives were less successful.

Most importantly, the paper explains how the capabilities developed and delivered in excess of the investment within the projects implementation phase and how Maersk Oil UK continues to gain value of the mature assets.

Summary: Full project cycle 1.5 yearsScope includes 3 subsea operated hubs for 8 fields with a total of 45 producers, 13 water injectors and 2 gas injectorsPayback within the project lifecycle.
Moving CO2 EOR offshore
Authors: Goodyear S G , Koster M P , Marriott K A , Paterson A , Sipkema A W , Young I M
Published: September 2011

CO2 can be an effective EOR agent and is the dominant anthropogenic greenhouse gas driving global warming. Capturing CO2 from industrial sources in EOR projects can maximize hydrocarbon recovery and help provide a possible bridge to a lower carbon emissions future, by adding value through EOR production and field life extension, and providing long term secure storage post-EOR operations.

Shell is working to implement new generation CO2 projects, including offshore applications. Based on recent offshore project design experience, this paper describes the challenges in moving CO2 EOR from onshore to offshore and the solutions developed, in the key areas of safety, facilities, wells, subsurface and piloting. The overriding design principle in any project is HSE. Offshore operations brings a new set of challenges over inventory, pressure, confined spaces and evacuation, with conventional emergency procedures requiring modification because of the different physical characteristics of CO2 releases compared to hydrocarbon gas. Surface facilities need to be simple to minimise CAPEX, weight and space while maintaining flexibility, since there is less scope to incrementally evolve the surface facilities as is the case onshore. Balancing the tension between these objectives requires very close surface and subsurface integration to find optimal and cost-effective solutions. This is illustrated with three key decision areas: gas treatment options for back produced CO2 and hydrocarbon gas, artificial lift and facilities capacity.

A novel integrated CO2 gas lift system is described. This simplifies facilities and reduces CAPEX and OPEX, while at the same time providing a high degree of flexibility and risk management over the EOR life cycle in terms of subsurface uncertainty and reducing the issues around molecular weight variation in the recycled gas and the degree of turndown required in the facilities in the early years of EOR operations.
Mobile Workforce Integration with Process Safety Management Framework Enables Sustained Improvement
Authors: Lough Victor
Published: September 2011

Recent incidents have highlighted the increased importance of situation awareness and its relationship to crisis management, With studies showing some 40% of incidents being related to operational error the need for an effective process safety management (PSM) framework which melds procedural automation with a previously IT centric business process management (BPM) environment could be seen to be advantageous. The final hurdle to a fully integrated solution has been the capturing of stranded assets e.g. where data collection is not possible, consistency of timely manual information or a heavy reliance on experienced human elements to consider information context.

The realization that an "Incident free" mission statement can effectively drive business strategy when used in conjunction with a mobile workforce is acknowledged. When used as part of an operator driven reliability program, we have a solution which captures tacit knowledge, improves inter-departmental collaboration and enables sensor to boardroom visibility. This Enterprise Control model enables the right people to consistently do the right thing optimally planned within the operational schedule.

This paper will describe how technology can be used as a change agent, not only to enable the consistent monitoring of previously stranded assets (People, Plant & Processes) but to change the workflow dynamics of the PSM model with field proven improvements in Safety and Productivity.
Development of Ball-and-Pocket Gripping Technology to Overcome Slip Handling Limitations
Authors: Jarski Justin , Yousef Faisal , Vandervort Kurt , Campbell-Smith Greg
Published: September 2011

Presents a new pipe gripping method using spherical balls to replace conventional die slips with the potential for significantly less damage to and better load distribution around pipe during handling. Describes the testing scope, results and analysis of ball versus slip comparison testing conducted under identical conditions.
Superficial temporal artery calcification in patients with end-stage renal disease: Association with vascular risk factors and ischemic cerebrovascular disease
Authors: Anwar Zeeshan , Zan Elcin , Carone Marco , Ozturk Arzu , Sozio Stephen M , Yousem David M
Published: September 2011

Background and Purpose: Extracranial superficial temporal artery (STA) calcification is an unusual finding seen in patients with chronic kidney disease and has unknown ramifications with respect to intracranial ischemic disease. We sought to determine the association between the risk factors for vascular calcification and this rare phenomenon, in patients with chronic renal failure, and to assess the coexistence of cerebral ischemia. Materials and Methods: Medical records and laboratory data on risk factors for vascular calcification were retrospectively retrieved for 453 patients with a discharge diagnosis of end-stage renal disease (ESRD). CT head examinations were reviewed to identify and associate STA calcification with 1) risk factors for the vascular calcification, 2) intracranial artery calcification, and 3) cerebral ischemia (white matter and/or cortical ischemic changes). Results: STA calcification was present in 9.9% (45/453) of the studied cohort. The prevalence of cerebral ischemia was 24.4% (11/45) in patients with STA calcification and 9.3% (38/408) in patients without it. Diabetes mellitus (OR: 2.56, 95% CI: 1.059-6.208; P=0.037) was independently associated with the risk of STA calcification. The risk of cerebral ischemia, however, was not related to STA calcification (P=0.221). Conclusion: The presence of diabetes mellitus is important in describing the risk of STA calcification in patients with ESRD, whereas age, gender, hypertension, serum calcium, serum phosphate, or serum hemoglobin levels are not. The risk of cerebral ischemia is not related to STA calcification but has the strongest association with diabetes mellitus.
Tibial hemimelia in Langer–Giedion syndrome with 8q23.1‐q24.12 interstitial deletion
Authors: Carvalho Daniel Rocha , Santos Savana Camilla Lima , Oliveira Maria Dulce Valverde , Speck‐Martins Carlos Eduardo
Published: September 2011

Langer–Giedion syndrome (LGS) (OMIM 150230) is defined as a contiguous gene syndrome caused by loss of functional copies of the TRPS1 and EXT1 genes usually secondary to 8q microdeletion. Tibial hemimelia (TH) is the least common lower limb deficiency characterized by hypoplasia of the tibia with relatively intact fibula. We describe the third report of LGS with bilateral TH and an 8q23.1‐q24.12 interstitial deletion. It is not possible to exclude that this association is fortuitous, but our report reinforces the suggestion of a putative gene involved in limb development in this chromosomal region interval. © 2011 Wiley Periodicals, Inc.
Effects of ptb knockout on butyric acid fermentation by Clostridium tyrobutyricum
Authors: Zhang Yali , Yu Mingrui , Yang Shang‐Tian
Published: September 2011

Clostridium tyrobutyricum ATCC 25755 is an anaerobic, rod‐shaped, gram‐positive bacterium that produces butyrate, acetate, hydrogen, and carbon dioxide from various saccharides, including glucose and xylose. Phosphotransbutyrylase (PTB) is a key enzyme in the butyric acid synthesis pathway. In this work, effects of ptb knockout by homologous recombination on metabolic flux and product distribution were investigated. When compared with the wild type, the activities of PTB and butyrate kinase in ptb knockout mutant decreased 76 and 42%, respectively; meanwhile, phosphotransacetylase and acetate kinase increased 7 and 29%, respectively. However, ptb knockout did not significantly reduce butyric acid production from glucose or xylose in batch fermentations. Instead, it increased acetic acid and hydrogen production 33.3−53.8% and ∼11%, respectively. Thus, the ptb knockout did increase the carbon flux toward acetate synthesis, resulting in a significant decrease (28−35% reduction) in the butyrate/acetate ratio in ptb mutant fermentations. In addition, the mutant displayed a higher specific growth rate (0.20 h−1 vs. 0.15 h−1 on glucose and 0.14 h−1 vs. 0.10 h−1 on xylose) and tolerance to butyric acid. Consequently, batch fermentation with the mutant gave higher fermentation rate and productivities (26−48% increase for butyrate, 81−100% increase for acetate, and 38−46% increase for hydrogen). This mutant thus can be used more efficiently than the parental strain in fermentations to produce butyrate, acetate, and hydrogen from glucose and xylose. © 2011 American Institute of Chemical Engineers Biotechnol. Prog., 2012
Comparison of several mathematical models for describing the joint effect of temperature and ph on glucanex activity
Authors: Prieto Miguel Angel , Vázquez José Antonio , Murado Miguel Anxo
Published: September 2011

The aim of the present work was to evaluate with different statistical criteria the suitability of nine equations for describing and optimizing the simultaneous effect of temperature and pH on glucanex activity using two characteristic polysaccharides (curdlan and laminarin) as substrates. The most satisfactory solutions were found with an empirical equation constituted with parameters of practical interest (Rosso model), and a hybrid model between the Arrhenius equation and the mathematical expression generated by the protonation‐hydroxylation mechanism (Tijskens model). The joint optimal values of pH and temperature calculated with the Rosso model were obtained at 4.64 and 50°C with curdlan and 4.64 and 48°C using laminarin as substrate. © 2011 American Institute of Chemical Engineers Biotechnol. Prog., 2012
Synergistic effect of resveratrol and quercetin released from drug‐eluting polymer coatings for endovascular devices
Authors: Kleinedler James J. , Foley John D. , Alexander J. Steven , Roerig Sandra C. , Hebert Valeria Y. , Dugas Tammy R.
Published: September 2011

This study describes the development and evaluation of novel polymer films that provide controlled release of two vascular‐protective polyphenols for endovascular devices. Resveratrol (RESV) and quercetin (QUER) have antimigratory and antiproliferative actions on vascular smooth muscle cells (VSMCs), inhibit both platelet and inflammatory cell activation, and promote endothelial cell function. Our aim is to develop and characterize coatings that release these drugs within a therapeutic range. The most synergistic drug combination, as determined by isobolographic analysis, was incorporated into an arborescent poly(styrene–isobutylene–styrene) tri‐block polymer (arbIBS) and applied to stainless steel coupons using an electrospray process. Physical characterization of the resulting coating revealed a film featuring micro‐scale architecture consisting of drug‐containing domains. To determine drug‐mediated effects, vascular cells were exposed to coatings incorporating several loadings of RESV and QUER. Results from this study indicate that arbIBS exhibits no cytotoxicity, and that the films release RESV and QUER at therapeutic levels, dose‐dependently inhibiting macrophage activation, VSMC proliferation, and platelet stimulation. We conclude that RESV and QUER released from arbIBS interfere with key processes responsible for in‐stent stenosis, suggesting that RESV and QUER may have utility as therapeutics in a novel coating for device‐based interventions. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2011.
Structure and properties of the graft copolymer of starch and p‐hydroxybenzoic acid using horseradish peroxidase
Authors: Lv Shenghua , Gong Rui , Ma Yanfen
Published: September 2011

A modified starch tannage was synthesized by free radical graft copolymerization of degraded starch with p‐hydroxybenzoic acid (pHA) using horseradish peroxidase/H2O2 as the initiator. In this study, the effects of the degree of degradation of the starch, dosage of pHA, polymerization temperature, system pH, and horseradish peroxidase content on the tanning properties of the graft copolymer were investigated. The shrinkage temperature of leather tanned by the graft copolymer was 78 °C. The thickness increment ratio of the retanned leather was 21.6%, and meanwhile the retanned leather showed better softness. The results indicate that the graft copolymer has excellent tanning and retanning properties. The structure of the graft copolymer was analyzed by Fourier Transform Infrared Spectroscopy (FTIR), 1Hydrogen‐Nuclear Magnetic Resonance (1H‐NMR), and 13Carbon‐Nuclear Magnetic Resonance (13 C‐NMR) and Gel Permeation Chromatography (GPC). Compared with conventional methods, we show that a “green” leather tannage could be achieved using a radical graft copolymerization of starch and phenols. Copyright © 2011 John Wiley & Sons, Ltd.
Empirical taxonomy of refactoring methods for aspect‐oriented programming
Authors: Alshayeb Mohammad , Al‐Jamimi Hamdi , Elish Mahmoud O.
Published: September 2011

Refactoring improves software quality by improving the design of existing code through changing its internal structure while preserving its behavior. Improving one quality attribute may impair other quality attributes. A number of refactoring methods were proposed specifically for aspect‐oriented systems. However, there are no guidelines to help aspect‐oriented software designer decide which refactoring methods to apply to optimize a software system with regard to certain design goals. In this paper, we propose a taxonomy/classification of refactoring methods for aspect‐oriented programming based on their measurable effect on software quality attributes using six open‐source aspect‐oriented software systems. Copyright © 2011 John Wiley & Sons, Ltd.
Direct Reprogramming of Melanocytes to Neural Crest Stem-Like Cells by One Defined Factor
Authors: Zabierowski Susan E. , Baubet Valerie , Himes Benjamin , Li Ling , Fukunaga-kalabis Mizuho , Patel Sonal , McDaid Ronan , Guerra Matt , Gimotty Phyllis , Dahamne Nadia , Herlyn Meenhard
Published: September 2011

Mouse and human somatic cells can either be reprogrammed to a pluripotent state or converted to another lineage with a combination of transcription factors suggesting that lineage commitment is a reversible process. Here we show that only one factor, the active intracellular form of Notch1, is sufficient to convert mature pigmented epidermal-derived melanocytes into functional multipotent neural crest (NC) stem-like cells. These induced NC stem cells (iNCSCs) proliferate as spheres under stem cell media conditions, re-express NC-related genes, and differentiate into multiple NC-derived mesenchymal and neuronal lineages. Moreover, iNCSCs are highly migratory and functional in vivo. These results demonstrate that mature melanocytes can be reprogrammed toward their primitive NC cell precursors through the activation of a single stem cell-related pathway. Reprogramming of melanocytes to iNCSCs may provide an alternate source of NCSCs for neuroregenerative applications.
Limbal Epithelial Stem/Progenitor Cells Attract Stromal Niche Cells by SDF-1/CXCR4 Signaling to Prevent Differentiation
Authors: Xie Hua-Tao , Chen Szu-Yu , Li Gui-Gang , Tseng Scheffer C.G.
Published: September 2011

Corneal epithelial stem cells (SCs) are an ideal model for investigating how adult lineage-committed epithelial SCs are regulated by an anatomically defined and accessible niche, that is, limbal palisades of Vogt, located between the cornea and the conjunctiva. We have used collagenase digestion to isolate the entire limbal epithelial SCs and subjacent mesenchymal cells, and we have demonstrated that their close association is crucial for promoting epithelial clonal growth, implying that the latter serves as niche cells (NCs). After their close association was disrupted by trypsin/EDTA, single SCs and NCs could reunite to generate sphere growth in three-dimensional Matrigel in the embryonic SC medium, and that such sphere growth initiated by SC–NC reunion was mediated by SDF-1 uniquely expressed by limbal epithelial progenitor cells and its receptor CXCR4, but not CXCR7, strongly expressed by limbal stromal NCs. Inhibition of CXCR4 by AMD3100 or a blocking antibody to CXCR4 but not CXCR7 disrupted their reunion and yielded separate spheres with a reduced size, while resultant epithelial spheres exhibited more corneal differentiation and a notable loss of holoclones. For the first time, these results provide strong evidence supporting that limbal SC function depends on close physical association with their native NCs via SDF-1/CXCR4 signaling. This novel in vitro model of sphere growth with NCs can be used for investigating how limbal SC self-renewal and fate decision might be regulated in the limbal niche.
Consumers can enhance ecosystem productivity and stability in changing environments
Authors: Fukui Shin , Miki Takeshi , Shimada Masakazu
Published: September 2011

There is increasing interest in the impacts of pulsed resource inputs (e.g., seasonal fluctuations in primary production) on ecosystem properties. However, theoretical models have focused on the ecosystem role of consumers only in stable environments. We investigated how the consumption rate affects ecosystem properties when resource supplies are pulsed using a simple model with numerical simulations. We initially investigated how primary production responds to resource supply shortages under various consumption rates and found that a vigorous consumer attenuates a rapid reduction in primary production. We next examined ecosystem properties under pulsed resource supplies. Intermediate consumption enhances primary production. The consumption rate that maximizes productivity differs for producers and consumers in a given resource supply environment, irrespective of the pattern of pulsation. The enhancement of primary production and the maximization of secondary production occur simultaneously in a stable environment but are not always the same when the resource supply is pulsed. We also investigated the variability of primary production and found that intermediate consumption rates reduce its coefficient of variation. In addition, we found that consumers with either very low or very high consumption rates are vulnerable to extinction when resource supplies are pulsed. Therefore, consumers with intermediate consumption rates contribute not only to the enhancement and stabilization of primary production but also to the stability of the consumer population itself.
The effects of rooting frequency and position of rooted ramets on plasticity and yield in a clonal species: an experimental study with Glechoma hederacea
Authors: Roiloa Sergio R. , Hutchings Michael J.
Published: September 2011

Clonal plants produce numerous ramets that can be distributed over a considerable area. Resources are translocated between ramets, especially when they occupy microsites of different quality, or places where leaves or roots cannot be deployed. It is common for a proportion of the ramets of clones and clonal fragments to lack roots. We conducted a greenhouse study using clonal fragments of Glechoma hederacea to examine the effects of differences in the number and position of rooted ramets on yield and plasticity of clonal fragments. We hypothesized that (1) mass of roots and root mass ratio would increase as the number of rooted ramets decreased, (2) plasticity in rooted ramets would buffer the clonal fragment against reduction in yield as the number of rooted ramets declined, (3) ramet plasticity in response to the absence of rooting, and the beneficial effects of this plasticity, would be greater when older ramets were rooted. The same yield was achieved in clonal fragments with only one out of four ramets rooted as in clonal fragments with all four of their ramets rooted, regardless of whether rooting was confined to older or younger ramets. Plasticity in biomass allocated to roots was greater in older rooted ramets succeeded by unrooted ramets than in younger rooted ramets preceded by unrooted ramets. Modular plasticity, involving both direct responses to local conditions, and indirect responses to the conditions experienced by connected modules, buffered performance against variation in rooting ability, enabling clonal fragments to maintain their yield and lateral expansion even when a high proportion of their ramets lacked roots.
Devonian Ichnofossils from the Farakah Muth Section of the Pin Valley, Spiti Himalaya
Authors: Parcha S. K. , Pandey Shivani
Published: September 2011

The Muth Formation is one of the most characteristic marker horizon traced throughout the northwestern Himalaya. The present studies were carried out in the Farakah Muth (Pin Valley) section of Spiti Basin. The formation uniformly consists of quartzarenite with a high textural and compositional maturity. The development of carbonate beds in the upper part of the Muth Formation separates it conformably from the overlying Lipak Formation. A variety of traces were observed throughout the succession, includes: Metaichna, Planolites, Skolithos, vertical and horizontal burrows. The presence of ichnofossils in the Muth Formation of the Farakah section indicates subtidal settings having soft sandy substrate, whereas, the gradual maturity of the quartz grains from base to top indicates deposition under high energy condition.
Reconnaissance of Quaternary Sediments from Khasi Hills, Meghalaya
Authors: Prokop Pawel , Bhattacharyya Amalava
Published: September 2011

Khasi Hills area of Meghalaya, one of the highest rainfall zones of the world has been explored to understand the spatial and temporal extent of Quaternary sediments. In general such deposits are restricted to shallow depths in most of the sites except in one site where it is 600 cm thick. AMS C-14 dates of these deposits suggest that sediments deposited are mostly of Holocene or in rare cases belong to later part of Pleistocene. Early Quaternary deposit is either missing or yet to be explored from this region. Natural hazards combined with human activity effecting degradation of vegetation and sediment cover are probably the main cause for poor Quaternary exposure at the region.
Fractal Analysis of Major Faults in India on a Regional Scale
Authors: Sengupta P. , Nath S. K. , Thingbaijam K. K. S. , Mistri S.
Published: September 2011

The seismicity of a region is implicit of the causal faulting mechanisms and geodynamic diversity of the subsurface regime nucleating earthquakes of different magnitudes, several of which may be as devastating as ones historically reported in global perspective of tectonic complexity as in the case of india. Fractal analysis using box-counting method for the major fault networks across the country estimates fractal dimension, Df, values to be varying between 0.88 and 1.36. The fault segments in parts of northwest Himalayas, northeast India and Indo-Gangetic plains, are observed to be associated with higher Df values implicating high seismicity rates. On the other hand, low Df values in the peninsular India indicate isolated pattern of the underlying faults. The fractal dimension is observed to be indicative of predominant faulting types – higher values conforming to thrust faulting mechanism while lower to strike slip tectonism.
Weathering and Landslide Occurrences in Parts of Western Ghats, Kerala
Authors: Sajinkumar K. S. , Anbazhagan S. , Pradeepkumar A. P. , Rani V. R.
Published: September 2011

The climatic condition of Western Ghats has influenced the process of weathering and landslides in this mountainous tract along the southwest coast of India. During the monsoon period, landslides are a common in the Western Ghats, and its intensity depends upon the thickness of the loose unconsolidated soil formed by the process of weathering. Debris landslides with a combination of saprock, saprolite and soil, indicate the role of weathering in landslide occurrences. This paper reports on how the weathering in the windward slope of Western Ghats influences the occurrence of landslides and the factors which accelerate the weathering process. Rock and soil samples were collected from the weathering profile of hornblende gniess and granite gneiss. The chemical analysis and the calculated Chemical Index of Alteration (CIA) indicate the significant weathering and its possible influence on landslide occurrences in the study area. Mainly, the CIA value of lateritic soil and forest loam indicated the extent of high chemical weathering in this region. Rainfall is the dominant parameter influencing the chemical weathering process. In addition, deforestation, land use practices and soil erosion are some of the other important factors accelerating the weathering process and landslide occurrences in the region. The locations of the previous landslides superimposed on geology and soil show that most of the landslide occurrences are associated with the highly weathered zone, particularly lateritic soil and the ‘severe’ (rock outcrop) erodability zone.