bluuebunny/crossref_metadata_2025 huggingface dataset:
Application of Logistic Mathematical Model to Simulate the Consumption of Natural Gas in Brazil Until 2020
Authors: Vasconcelos Claudemir Duca , Lourenço Sérgio Ricardo , Gracias Antonio Carlos , Librais Valter
Published: July 2013

Over the next two decades Brazil expects to see an increasing share of energy provided by natural gas. Natural gas use in 2010 was 10.2% of the total energy consumption and comprised 73 million cubic meter per day. Natural gas is considered one of the main energy sources which contributes and will contribute to the development of the country by providing economic, social and environmental benefits. This work uses population dynamics mathematical model (Verhulst) in order to analyze the evolution of natural gas consumption in Brazil within a forecast until 2020. The Verhulst model, also known as “logistic”, has been advanced in its application and shows that the population dynamics mathematical models, within their basic assumptions, may allow estimating the growth of a population or other variable with the same characteristic. The calculation to solve the differential equations, linear regression, method of least squares and graphics were performed using the MatLab software. Through simulations it was found that the mathematical model can be applied to natural gas consumption in Brazil. Simulations using the proposed model show a tendency of saturation in the consumption between 70 and 90 million cubic meters per day. These numbers are below the projected numbers until 2020 according to forecast presented in the energy plan. The results of this study indicate that the growth of natural gas consumption is stable and is within the limit of saturation related to the Brazilian market.
A Parametric Study on Buckling Response of High Strength Steel Pipes With Anisotropic Material Properties
Authors: Fathi Ali , Cheng J. J. Roger
Published: July 2013

Highly pressurized pipelines crossing harsh environments need to have two chief materials properties; they should have high strength in transverse direction to resist high operating pressers; and high deformability in the longitudinal direction to accommodate externally induced deformations. Pipeline producers try to deal with this dual demand in their high strength steel (HSS) linepipe products by enhancing the yield strength in the transverse direction and maintaining deformability in the longitudinal direction. This practice results in significant level of anisotropy in yielding and early plastic regions. The effects of material anisotropy on complex pipeline limit states such as local bucking is not fully understood. This paper presents the results of a numerical study on the effects of material anisotropy on the buckling response of HSS pipes. The effects of operating pressure, diameter-to-thickness ratio, material grade, strain hardening and the ratio of longitudinal-to-transversal yield strength were taken into account. Combined (isotropic-kinematic) hardening material modeling technique — previously introduced by the authors — was employed in this study. The results of this study are presented in several graphs showing the variation of the critical buckling strain versus the level of material anisotropy of HSS pipes with different geometry, material and operation conditions. These results provide an insight into the effects of material properties on the buckling resistance of pipes, especially when anisotropy is present.
Southern Pipelines Strategic Plan Management Tools
Authors: Boszczowski Eduardo Bomfim , Silva Gabriel José de Castro Santos , da Cruz Kleber Vinicius
Published: July 2013

The Petrobras Transporte SA Strategic Plan (SP) is an instrument that contains the strategic positioning of the company and aims at guiding the management and action plan in the achievement of the corporate goals. Apart from that, the SP explains the portfolio of investment projects by segment and business area.

Every year since 2009, the Terminals and Pipelines Board of Directors have allocated the strategic objectives under their responsibility in order to ensure the alignment of the strategic planning with the operational activities of the company. For this end the strategic objectives are distributed between the Pipeline Executive Management and the Marine Terminals Executive Management. This division allows for the assignment of responsibilities in a structured way throughout the organization, this way setting up the Tactical Plan of the Business Units.

To achieve the goals, the evolution of the Tactical Plan of the Pipelines Executive Management is monitored through regular meetings with the Regional Managements as well as through diversions, potential difficulties and corrective and preventive actions. Besides regular meetings, several instruments have been implemented for effective monitoring of the Tactical Plan, e.g. a web based platform for sharing information, video conferences, performance indicators and other tools that enable the management of the actions.

This paper aims to describe best practices applied to the purposes and goals of the Pipeline Tactical Plan under the management of the Southern Pipelines Management, describing their Benefits to the company in a long-term horizon under conditions of uncertainty of the international energy market.
Burnthrough Prediction for In-Service Welding: Past, Present and Future
Authors: Boring Matthew A.
Published: July 2013

The methods of determining burnthrough risk have changed over the years. The first burnthrough limits were developed experimentally and then, with the development of computers, came computer models. The first major advancement in computer models came at Battelle, in the early 1980s, with the development of the “Hot-Tap Thermal-Analysis Models.” The Battelle models use two-dimensional numerical solutions to predict the inside surface temperature as a function of the welding parameters, pipe parameters, and the operating conditions. The Battelle model considers an inside surface temperature of less than 1800°F (982°C) when using low-hydrogen electrodes, [1400°F (760°C) when using cellulosic-coated electrodes] to be safe. Since the release of the Battelle model, introduction other models have been developed which are based on Battelle’s logic as well as other approaches. PRCI, as well as others, has funded research to develop an alternative burnthrough prediction model which is based on a thermo-mechanical approach taking into account the stress associated with pressurized pipe. These alternative approaches differ from Battelle’s criteria which only uses the inside surface temperature as the lonely determining factor of safe welding practices.
Extension of Current Defect Assessment Methods for Gouge and Corrosion Defects in X80 Grade Pipeline
Authors: Malatesta Giuliano , Meleddu Andrea , Owen Robert , Zarea Mures
Published: July 2013

The increasing demand for natural gas affects the type of transportation, both from the strategic and the economic point of view. Long-distance pipelines are a safe and economic way to transport the gas from production sites to end users. Hence, pipes producers need to supply the market executing projects where high strength material is involved, to reduce the steel use.

Among high strength steel grade pipes (X80 - X100 - X120), the X80 grade is already in use for a number of gas pipelines in the world since many years.

There is a need to evaluate the suitability of extending the current Fitness For Purpose methods to X80 grade steel linepipe, since the existing guidance was developed and validated mainly on test data coming from steel pipes of grade lower than X80. Hence they could not be directly applied to X80 grade pipes, but should be experimentally verified, otherwise their straightforward extrapolation would be questionable.

EPRG recognized the need to cover this gap and launched a specific project, aimed at verifying the applicability of the presently available criteria to X80 grade, with particular focus on corrosion and gouge types of defects, longitudinally oriented.

The project includes the collection and review of available tests data and FFP criteria, and the identification of the most promising among those collected. Four hydraulic full scale burst tests on X80 representative pipes (helically and longitudinally welded) containing simulated corrosion and gouge defects have been carried out to experimentally verify the applicability of the criteria to the X80 grade pipes.

The selected criteria for the corrosion (DNV RP-F101) and for the gouge (Battelle NG-18) defects revealed to be suitable for X80 grade pipes too, as demonstrated by the accuracy in predicting the failure pressure of the experimental tests and of the literature database. The criteria showed to be even more accurate for X80 grade than they were for lower grades.

Finally, it is worth mentioning that the selected criteria did not need any correction factor for obtaining the best prediction. Such a result is a demonstration of the sound theory behind the criteria.
Assessment Criteria and Burst Pressure Prediction for Pipelines With Long Blunt Defects
Authors: Zhu Xian-Kui , Leis Brian N.
Published: July 2013

Corrosion assessment analysis and burst pressure prediction for an aged pipeline with blunt corrosion defects are essential to its integrity. It has been known that the flow stress based corrosion criteria including ASME B31G and PRCI RSTRENG are often conservative to use, but can be non-conservative in practical applications. The ultimate tensile stress based corrosion criteria such as PCORRC and LPC models largely improved the burst pressure prediction for corrosion defects, but the practice still showed certain non-conservatism of these newer models. This paper reviews and evaluates the commonly-used corrosion criteria. In order to improve the existing criteria for predicting burst pressure for long corrosion defects, three new theoretical models with consideration of strain hardening response for the corroded pipe are developed in terms of Tresca yield criterion, von Mises yield criterion, and a new multi-axial yield criterion, i.e., average shear stress yield criterion proposed recently by the present authors. The existing corrosion criteria and the proposed theoretical models are evaluated using experimental burst data for long machined defects and for long real corrosion defects removed from service. It is found that ASME B31G is over-conservative for long defects, but can be non-conservative for deep defects with intermediate lengths. RSTRENG is conservative for short defects. In contrast, PCORRC (or LPC) and the proposed ZL model predict reasonably conservative results for long corrosion defects.
Multi Tiered Approach to Slope Movement Management: Case Study
Authors: Sen Millan , Richmond John , Dinovitzer Aaron , Fredj Abdelfettah
Published: July 2013

A major slope in southern Manitoba is currently experiencing deep seated movements of approximately 60mm per year. This 20m high × 70m long slope contains a pipeline right of way with five large diameter crude oil lines that were constructed from 1950–1998. It is estimated that the slope has moved over 3 meters since the pipeline installations. Management of the effects of this slope movement on the pipelines has involved cross-functional strategies that include geotechnical, integrity, and stress evaluations.

The slope is assessed annually by a geotechnical engineer, and the most likely cause for the slope movements has been determined. Slope monitoring equipment has been installed at key locations and is monitored at frequent intervals. A toe berm has been installed to prevent lower slope failure at the creek bed that is located at the slope toe.

A finite element stress analysis, which considers the interaction between the soil movement and pipeline, has been generated. This stress analysis evaluated the pipeline stresses due to the slope movements to date, and also due to a possible sudden mass movement. The results are backed up by a bending strain analysis based on inertial in-line inspection data was conducted for several of the lines.

This paper presents an overview of the engineering assessment considering structural, material, geotechnical and operational concerns involved in developing an integrity management action plan.
Developing a Predictive Model of Near Neutral pH Stress Corrosion Cracking of Underground Pipelines
Authors: Conrad Brett , Chen Weixing , Eadie Reg , Kania Richard , Van Boven Greg , Worthingham Robert
Published: July 2013

Near neutral pH Stress Corrosion Cracking (NNpHSCC) associated with external corrosion of pipelines is an issue facing industry today. Determining areas of NNpHSCC susceptibility is crucial to developing Integrity Management Programs and inspection dig schedules. This research involved collecting pertinent field data (inspection dig reports, failure reports, loading histories) and developing a predictive model to help identify areas and lines most susceptible to NNpHSCC. The predictive model focused on the loading history (in this case, SCADA data) patterns to classify different groups of loading conditions. Hydrogen has been identified and established in previous literature to be a major contributor to NNpHSCC. Different Hydrogen Enhancement Factors (HEF) were applied based on how the mechanisms of hydrogen embrittlement react to the respective loading conditions. The predictive model illustrated a dormancy behaviour, similar to the one seen in field conditions and a mechanically activated growth dependent on both hydrogen and previous loading scenarios. A correlation was shown between a limited field sampling and the predicted values. Further improvements and calibrations can be made with the gathering of more field data and continued experimental validation. Once this validation has been performed, this model has the possibility to illustrate what loading conditions increase a segments susceptibility to NNpHSCC.
Achieving Maximum Crack Remediation Effect From Optimized Hydrotesting
Authors: Chen Weixing , Kang Yongwang , Eadie Reg , Kania Richard , Van Boven Greg , Worthingham Robert
Published: July 2013

Hydrostatic testing is a key method for managing SCC in oil and gas pipelines. Benefits are achieved by eliminating defects above a critical size for the hydrotest pressure and hence achieving a post-test period without operating failure. Other benefits are related to temporary growth retardation after hydrotest because of crack tip blunting. Conversely, benefits of such a test could be offset by stable flaw growth in the previously dormant population and growth of cracks during hydrostatic loading. Although this type of growth behaviour has been previously analyzed, it was only assessed from tests in air, which neglects the effects of corrosive environments.

Recent research has shown that crack growth can occur during hydrotests at much smaller crack dimensions than those originally analyzed. The adverse effect of hydrotesting is negligible if it initiates crack growth only on large-size cracks that are near the final stage of pipeline life. However, benefits of hydrotest would become uncertain if hydrostatic loading induces crack growth when crack dimensions are relatively small. This reduction in pipeline remaining lifetime by hydrostatic testing can be significant considering the fact that several hydrotests may be performed in the lifetime of a pipeline. Although hydrotests would usually re-condition the crack tip so that a lower crack growth rate can be expected for a limited time, it is questionable whether the reduced growth rate would compensate for the loss of life because of the crack growth during hydrotesting. Therefore, the overall benefits of hydrotesting must be evaluated from the viewpoint of life extension and pipeline safety.

Effects of hydrostatic tests in this investigation were analyzed based on two competing morphological conditions at the crack tip before, during and after hydrostatic testing, that is, crack tip blunting and crack tip sharpening. Crack tip sharpening is related to the hydrogen effects and mechanisms of cyclic loading, while the crack tip blunting is attributed to low temperature creep of the pipeline steels. From the investigation, strategies aimed at achieving maximum crack remediation are proposed.
Tensile Strain Capacity of Spiral Pipes
Authors: Liu Ming , Wang Yong-Yi , Collins Laurie
Published: July 2013

Pipelines may experience high longitudinal strains from seismic events, frost heave, thaw settlement, unstable slopes, and mine subsidence, etc.. Those strains could be well beyond the elastic limit of the materials and the strain based design (SBD) criteria must be used. Most work on the SBD in recent years has been focused on the straight long seam pipes. The application of the SBD principles to the spiral pipes has not been examined.

Spiral-welded pipes are widely used for long-distance transmission pipelines. These pipes have a demonstrated history of satisfactory service. However, the performance of the spiral pipes under large longitudinal strains is not well understood.

The focus of this paper is the tensile strain capacity of spiral pipes. The crack driving forces of flaws in spiral welds under longitudinal tension strains were analyzed for X80 pipes. Unlike the girth weld flaws which see primarily mode-I crack driving forces, the spiral weld flaws see mode-I and mode III mixed crack driving forces. The mode-I and mode-III driving force components vary with the spiral angles and pressure conditions. It is found that the application of the internal pressure can greatly increase the mode-I component and the total crack driving forces.
Compare the Corrosion of 3%Cr Steel With X65 Pipeline Steel in Subsea CO2 Top-of-Line Corrosion Environment
Authors: Zhang Yunan , Xu Lining , Chang Wei , Lu Minxu , Zhang Lei , Guo Shaoqiang
Published: July 2013

CO2 Top-of-Line Corrosion (TLC) of carbon steel pipelines is a serious problem for subsea wet gas pipelines. A series of experiments were carried out in the high-pressure high-temperature condensation autoclave, in order to simulate the corrosion environment of TLC. The purpose of this paper was to compare the corrosion resistance of 3%Cr steel with API X65 pipeline steel in CO2 TLC environment. The composition and morphology of the corrosion scale were characterized by energy dispersive X-ray spectroscopy and scanning electron microscopy analyses. The results indicate that 3%Cr pipeline steel shows relative good resistance to CO2 TLC, with slight pitting at static condition, however, X65 suffers severe mesa corrosion. The analysis of composition and morphology revealed that the amorphous corrosion scales was formed on the surface of 3%Cr steel. The localized corrosion of 3%Cr steel may be related to the uneven filling of Cr compound under static condition.
A Rational Methodology for Detailed Pipeline Transient Hydraulic Analysis
Authors: Rodriguez Gabriela , Pavel Bogdan
Published: July 2013

Pressure waves in pipelines develop any time there is a change in fluid velocity. If the change in velocity is large enough, the magnitude of a travelling pressure wave can exceed the Maximum Operating Pressure (MOP) of the piping. It is a violation of the Canadian and US regulations for petroleum pipelines (Canada – CSA Z662 4.18 and United States – ASME B31.4) to operate a pipeline at pressures in excess of 110% MOP even for short periods of time. In order to meet standards and regulations, transient analyses are undertaken to verify whether the pipeline MOP profile is susceptible to overpressures and to recommend solutions for such cases.

This paper presents the results of a working group on developing a standard for the suite of transient scenarios and methodology to be used for detailed transient hydraulic analysis. The work consisted of reviewing and analyzing historical transient studies and, abnormal operating conditions / overpressure events recorded by Control Centre; as well as, incorporating new learning from operational lines.

Methodology standardization focused on four areas: selection of inputs, model scope and criticality of pipeline sections, pipeline initial state, and worst-case upset scenarios. As a result, this paper describes the most prudent approach for each area or step of a pipeline transient analysis; including the evaluation of mitigation options if required. Finally, the use of this methodology is illustrated on a crude oil pipeline.
Assessment of Recent Experimental Data on Collapse Capacity of UOE Pipeline
Authors: Marley Erica , Aamlid Olav , Collberg Leif
Published: July 2013

Recent developments in the offshore industry are resulting in an increasing demand for deep water pipelines. At greater water depths, the external pressure will be the governing parameter for wall thickness design, and the failure mode is collapse.

DNV’s reliability based standard, DNV-OS-F101, uses the collapse capacity model and corresponding safety factors calibrated in the SUPERB Joint Industry Project, finalized in the mid 1990’s. Since then, a vast amount of research on collapse capacity of deep water pipelines is performed, indicating that it is time to re-visit the design equation and safety factors currently in use.

This paper firstly summarizes the relevant collapse pressure equations for pipeline design. Secondly, the major points related to collapse capacity in SUPERB and DNV-OS-F101 are presented. Furthermore, results from an assessment of newer collapse tests of pipelines are described. Focus is on larger (UOE) pipes with D/t ratios less than 25, corresponding to water depths beyond 1000 m. The test results are compared to the outcome of earlier experimental projects. A difference between older and more recent tests is observed, with the newer having a considerably higher collapse capacity. Finally, a calibration of safety factors is performed, compared to existing factors and discussed.
Current State of Satellite-Based Right of Way Encroachment Monitoring for Mechanical Damage Prevention
Authors: Nickle Randy , Pevarski Rick , Piazza Mark , Rizkalla Moness , Graham Richard , Adlakha Paul
Published: July 2013

The past decade has seen the continued development and the implementation of satellite-based Right of Way (RoW) encroachment monitoring as an element of the pipeline industry’s toolbox for proactive prevention of mechanical damage.

This paper presents a brief overview of the underlying technology, the current applied capabilities and an illustration of where the technology fits within the industry’s toolbox. The early results of two ongoing studies concerning the implementation of satellite-based RoW encroachment monitoring are discussed. Both studies, sponsored by VUPS and PRCI-Alliance Pipeline respectively, were intended to further advance the technology and its delivery to the industry.

The VUPS-sponsored project demonstrated the feasibility of integrating satellite-based monitoring within the operations of a utility “one call” to deliver the technology’s benefits to several pipeline operators within the project’s area of interest. The PRCI-Alliance Pipeline sponsored study investigated the potential higher resolution detection capabilities of a virtual constellation of satellites.

Together the two studies demonstrate the applicability of the technology for Encroachment Monitoring and the means to deliver its benefits to the pipeline industry.
Building an Effective Pipe Procurement and Manufacturing Process
Authors: Afaganis Alexander J. , Christmas Larry
Published: July 2013

Over the last 5 years there have been a large number of transmission pipelines installed with much of the pipe procured and manufactured outside of North America — many from non-integrated pipe manufacturers. Over this same period there have been a significant number of pre-operation field hydrostatic testing pipe failures as a consequence of low and variable pipe strength, and chemical composition variations. A strong, structured and effective pipe procurement and manufacturing process following the proven “plan–do–check–act” quality assurance model can minimize such issues. Further, such a process can properly manage the inevitable process and product deviations ultimately minimizing project timeline disruptions and reducing project costs. A practical outline of the key features of such a system are discussed from the specification and bid package development through vendor qualification, bid contract review, slab, plate and pipe manufacturing (and the process control documentation and verification), manufacturing surveillance, and follow-up activities.
On the Collapse Pressure of Impanded Large Diameter Pipe (JCO-C)
Authors: Reichel Thilo , Pavlyk Vitaliy , Beissel Jochem , Aretov Ivan , Kyriakides Stelios
Published: July 2013

Current manufacturing technology for large diameter pipe, such as the UOE process, is known to result in pipe with reduced collapse pressure compared to a seamless one of the same steel grade and D/t. It has recently been demonstrated [1,2] that such deficient performance can be alleviated by finishing longitudinally welded pipe by compression. A newly developed cold sizing press, called Impander®, is used to produce pipe with reduced ovality, reduced residual stresses and increased compressive yield strength. The combination of these factors can lead to a significant increase in the collapse pressure of the pipe. The paper will review experimental and analytical results that demonstrate the improved collapse pressure of pipes manufactured by it. This improved performance was confirmed in a full-scale collapse experiment on a pipe finished by impansion of 1.1%. The test showed perfect agreement with the modelling. The collapse pressure was 37% higher than current design codes allow. Additional work has been performed aimed at evaluating the effect of low temperature heat treatment on the collapse pressure. A full-scale collapse test on impanded and heat-treated pipe has shown that a significant additional enhancement in collapse pressure results from the heat treatment. The paper will discuss the thermomechanical causes of these enhancements of the collapse pressure.
Paperless Track Inspection Record Keeping and Compliance
Authors: Price Tom , Blair Rick , Roney Michael , Graves Dave , Sharma Shriram , Ozkaya Armagon , Dick Matthew
Published: July 2013

Traditionally railway track inspections have been recorded on paper. As technology advances, so does the ability to record track inspections utilizing a paperless system. A paperless system allows for many advantages including rapid report generation and oversight to ensure compliance.

This paper briefly reviews the development and use of the Digital Track Notebook paperless track inspection record keeping system. Detailed in the paper is how the system complies with CFR 213.241 Electronic Record Keeping on items such as amending and data retention. Additionally this paper discusses how the system ensures regulatory compliance with Federal Railroad Administration and Transport Canada rules concerning inspection frequency and modes. Lastly, the paper discusses the deployment of the system in Canadian Pacific Railway (CPR).
Results of Fire Test of Aluminum Car Structure Bombardier Innovia APM 300 System
Authors: Lewis Kevin , Thomure Randall , Moore Scott , Olsson Goran , Rosario Angel
Published: July 2013

Passenger rail equipment is required to meet the fire test standards as outlined in NFPA 130 Standard for Fixed Guideway Transit and Passenger Rail Systems, 2010 Edition. Bombardier’s recently released INNOVIA APM 300 car was tested under the provisions of this standard. As part of the testing process, the car structure is subjected to direct flame (to the underside of the car structure) for a minimum 15 minutes in accordance with ASTM E 119. In anticipation of more stringent requirements from some potential customers, Bombardier decided to develop two options for vehicle fire protection. The first and base option is a vehicle that meets the 15 minute requirement. The next option is a vehicle that will survive an ASTM E 119 test for 30 minutes. This paper will summarize the results of the fire tests including pretest and post-test analysis and observations.
Duty Cycle and Transport Phenomenon Analysis of Battery Storage System for Hybrid Locomotive Application
Authors: Subhedar Sarang , Majumdar Pradip , Kilaparti Rao , Schroeder David
Published: July 2013

The interest for developing hybrid electric locomotives consisting of diesel engine, regenerative braking and battery storage is growing due to increased demand and cost of diesel oil, uncertainty in the steady supply of oil, and increased standards for reduced emissions. Electrical energy is lost from electric locomotives in the form of heat during dynamic braking. Routing this energy using a regenerative braking system into battery stacks can improve the overall efficiency as it can be used later to provide traction force during acceleration.

Objective of this study is to perform a feasibility analysis of modes of regenerating the energy developed in the braking and storing the energy in an electric battery storage system for use in railroad locomotive applications. Various road locomotive duty cycles, charge and discharge rates, and environmental conditions have been considered as this is expected to substantially influence the optimal performance and safety of the battery as well as the potential fuel savings that could be realized using a hybrid design. A computational algorithm is developed to determine the amount of energy that can be obtained from regenerative breaking during the run of locomotive and can be stored back into the stack of battery, which can be coupled with diesel engine to save additional consumption of fuel. A combined electrochemical and thermal simulation analysis of several battery configurations using multiphysics simulation code has also been performed in order to understand the thermal management and cooling requirements of the batteries subject to the charging and discharging requirements of a locomotive engine. Such an analysis assists in addressing the key issue of operating the battery at an maximum efficiency level while dissipating any excessive heat generated during the operation, and maintaining the battery at a desired temperature range using a cooling scheme.
Engaging High School Students in Research on Smoking Behavior
Authors: Munn Maureen M. , Oura Hiroki , Gallivan Mark , Van Horne Katie , Shouse Andrew W.
Published: July 2013

Exploring Databases, an IBI prize–winning module, enables students to conduct epidemiological research on smoking behavior using a database.
A General Strategy for the Chemoenzymatic Synthesis of Asymmetrically Branched
N
-Glycans
Authors: Wang Zhen , Chinoy Zoeisha S. , Ambre Shailesh G. , Peng Wenjie , McBride Ryan , de Vries Robert P. , Glushka John , Paulson James C. , Boons Geert-Jan
Published: July 2013

Sweet Variety

Proteins fold into a great variety of shapes—but, topologically, they always start as a more or less straight line of linked amino acids. In contrast, carbohydrates manifest a range of structures in which the sugar building blocks connect through multiple branch points.

Wang
et al.

(p.
379
, published online 26 July; see the Perspective by

Kiessling and Kraft

) designed a versatile precursor that could be transformed into many different branched glycans with distinct building blocks along each branch.
Identification of a Colonial Chordate Histocompatibility Gene
Authors: Voskoboynik Ayelet , Newman Aaron M. , Corey Daniel M. , Sahoo Debashis , Pushkarev Dmitry , Neff Norma F. , Passarelli Benedetto , Koh Winston , Ishizuka Katherine J. , Palmeri Karla J. , Dimov Ivan K. , Keasar Chen , Fan H. Christina , Mantalas Gary L. , Sinha Rahul , Penland Lolita , Quake Stephen R. , Weissman Irving L.
Published: July 2013

A Gene for Early Acceptance

One of the fundamental properties of the immune system is the ability to distinguish self- from nonself–histocompatibility. To gain insight into the evolution and molecular basis of histocompatibility,

Voskoboynik
et al.

(p.
384
) sought to determine the genetic basis for a natural transplantation reaction that occurs in
Botryllus schlosseri
, a colonial urochordate. Compatibility allows vascular fusion among individuals, whereas incompatibility results in an inflammatory rejection response. A single gene determined the outcome of the reaction. Like histocompatibility genes in higher organisms, this gene is polymorphic and is expressed in the tissues that participate in the transplantation reaction.
FtsZ Protofilaments Use a Hinge-Opening Mechanism for Constrictive Force Generation
Authors: Li Ying , Hsin Jen , Zhao Lingyun , Cheng Yiwen , Shang Weina , Huang Kerwyn Casey , Wang Hong-Wei , Ye Sheng
Published: July 2013

In a FtsZ

FtsZ is a guanosine triphosphatase that polymerizes into protofilaments at the bacterial division site. FtsZ recruits the accessory division proteins to the septum and also provides mechanical forces needed to constrict the membrane and reduce the cell width. However, how FtsZ generates mechanical force is unclear. While one popular model suggests that mechanical forces are generated by means of a change in FtsZ structure induced by guanosine triphosphate hydrolysis, nucleotide-dependent conformational transitions have yet to be observed in FtsZ monomer structures. Such transitions may be a feature of FtsZ only in its native protofilament-forming state.

Li
et al.

(p.
392
) sought to resolve this question by obtaining high-resolution structures of guanosine diphosphate–bound FtsZ filaments. The results suggest a complex and dynamic FtsZ protofilament network with a high degree of plasticity that is capable of generating forces to drive cytokinesis, during cycles of hydrolysis, while maintaining the structural integrity of individual monomers.
A Measure for Accounting
Why Calories Count: From Science to Politics.
Marion Nestle and Malden Nesheim. University of California Press, Berkeley, 2012. 298 pp. $29.95, £20.95. ISBN 9780520262881.
Authors: Nordstrom Kerstin
Published: July 2013

The authors' wide-ranging survey of calories will help readers appreciate personal and political dimensions of food choices.
Extinct, Yet Still Evolving
My Beloved Brontosaurus: On the Road with Old Bones, New Science, and Our Favorite Dinosaurs.
Brian Switek. Scientific American/Farrar, Straus, and Giroux, New York, 2013. 266 pp. $26, C$30, £17.99. ISBN 9780374135065.
Authors: Bernstein Rachel
Published: July 2013

Switek flavors his accounts of dinosaurs and dinosaur paleontologists with personal anecdotes and cultural reflections.
Flow Cytometric Detection of Mycobacterium avium subsp. paratuberculosis-Specific Antibodies in Experimentally Infected and Naturally Exposed Calves
Authors: Schillinger S. , Bridger P. S. , Bulun H. , Fischer M. , Akineden Ö. , Seeger T. , Barth S. , Henrich M. , Doll K. , Bülte M. , Menge C. , Bauerfeind R.
Published: July 2013

A desirable test to diagnose infections with
Mycobacterium avium
subsp.
paratuberculosis
facilitates identification of infected cattle prior to the state of
M. avium
subsp.
paratuberculosis
shedding. This study aimed at adjusting a flow cytometry (FC)-based assay, using intact
M. avium
subsp.
paratuberculosis
bacteria as the antigen, for diagnosis of
M. avium
subsp.
paratuberculosis
infections in calves. Serum samples were collected from experimentally infected (
n
= 12) and naturally exposed (
n
= 32) calves. Samples from five calves from positive dams were analyzed to determine the dynamics of maternal antibodies. Samples from adult cattle with defined infection status served as the standard (18
M. avium
subsp.
paratuberculosis
shedders, 22
M. avium
subsp.
paratuberculosis
free). After preadsorption with
Mycobacterium phlei
, sera were incubated with
M. avium
subsp.
paratuberculosis
and
M. avium
subsp.
avium
bacterial suspensions, respectively, followed by the separate detection of bovine IgG, IgG1, IgG2, and IgM attached to the bacterial surface.
M. avium
subsp.
paratuberculosis
-specific sample/positive (S/P) ratios were compared to enzyme-linked immunosorbent assay (ELISA) S/P ratios. In adult cattle, the FC assay for IgG1 had a sensitivity of 78% at a specificity of 100%. Maternally acquired antibodies could be detected in calves up to 121 days of life. While all but two sera taken at day 100 ± 10 postnatum from naturally exposed calves tested negative, elevated S/P ratios (IgG and IgG1) became detectable from 44 and 46 weeks postinoculation onwards in two calves infected experimentally. Even with the optimized FC assay,
M. avium
subsp.
paratuberculosis
-specific antibodies can only occasionally be detected in infected calves less than 12 months of age. The failure to detect such antibodies apparently reflects the distinct immunobiology of
M. avium
subsp.
paratuberculosis
infections rather than methodological constraints.
Rapid, Sensitive Recovery of Recombinant Attenuated Salmonella enterica Serovar Typhi Vaccine Strains from Human Blood
Authors: Lottenbach Kathleen R. , Kelly-Aehle Sandra M. , Brenneman Karen E. , Curtiss Roy , Frey Sharon E.
Published: July 2013

Prior to initiating a phase 1 dose escalation trial of the safety and immunogenicity of live, oral, recombinant, attenuated
Salmonella enterica
serovar Typhi vaccine strains in human subjects, the suitability of conventional blood culture procedures to rapidly and reliably detect the organisms in human blood was investigated. Blood culture specimens, with and without added growth supplements, were inoculated with study organism concentrations ranging from approximately 300 to as few as 1 to 2 CFU/10 ml culture and processed in a Bactec 9240 fluorescent series aerobic blood culture system. All cultures seeded with >6 CFU and 93% of cultures seeded with ∼1 to 2 CFU were identified as positive for microbial growth within 44 h of incubation. The results were within the performance standard of ≤5 days to detection that is expected for Gram-negative cultures seeded at 10 to 50 CFU/vial. Recovery of test organisms from blood culture was not improved by the addition of supplements, but cultures with added supplements were identified positive an average of 5 h sooner than those without added supplements. Reliable detection of the investigational vaccine strains at <1 CFU/ml of blood within 2 days in conventional blood culture without added supplements allowed for shortened confinement time of study volunteers without compromising subject safety.
A Single Intraduodenal Administration of Human Adenovirus 40 Vaccine Effectively Prevents Anaphylactic Shock
Authors: Yamasaki Satoshi , Miura Yoshiaki , Davydova Julia , Vickers Selwyn M. , Yamamoto Masato
Published: July 2013

Vaccine administration into the intestine is known to induce mucosal tolerance most efficiently. Therefore, developing a delivery system that targets the intestinal mucosa is expected to improve the efficiency of immunosuppression. Human enteric adenovirus serotype 40 (Ad40)-based vectors have the advantage of targeting intestinal mucosa, making them prime candidates as mucosal vaccine carriers for immunosuppression. Here, after both oral and intraduodenal administrations, the vector distribution of replication-defective recombinant Ad40 vectors (rAd40) was significantly higher than that of a conventional Ad vector based on human adenovirus 5 (Ad5) in ilea containing Peyer's patches. Single intraduodenal administration of rAd40 induced antigen-specific mucosal immunoreaction mediated by intestinal mucosal and systemic immunity. In ovalbumin-induced allergy mouse models, this approach inhibited antigen-specific delayed-type hypersensitivity reactions, diarrhea occurrence, and systemic anaphylaxis. Thus, a single intraduodenal administration of rAd40 provides a potent method of inducing allergen-specific mucosal tolerance and a new allergen-specific immunotherapy for overcoming problems with current therapies against life-threatening allergic reactions, including anaphylaxis.
Nonsuppurative Encephalomyelitis in a Calf in Japan and Isolation of Japanese Encephalitis Virus Genotype 1 from the Affected Calf
Authors: Katayama Takashi , Saito Sachie , Horiuchi Sanae , Maruta Tetsuya , Kato Tomoko , Yanase Tohru , Yamakawa Makoto , Shirafuji Hiroaki
Published: July 2013

Japanese encephalitis virus (JEV) was isolated from the cerebrum of a calf which showed severe neurological symptoms in late September 2009, and the JEV isolate was revealed to be of genotype 1. This is the first report describing the isolation of genotype 1 JEV from cattle.
Phenotypic and Molecular Characterization of Optochin-Resistant Streptococcus pneumoniae Isolates from Brazil, with Description of Five Novel Mutations in the
atpC
Gene
Authors: Pinto Tatiana C. A. , Souza Aline R. V. , de Pina Sandrine E. C. M. , Costa Natália S. , Borges Neto Armando A. , Neves Felipe P. G. , Merquior Vânia L. C. , Dias Cícero A. G. , Peralta José M. , Teixeira Lúcia M.
Published: July 2013

Optochin (Opt) susceptibility is used largely for the identification of
Streptococcus pneumoniae
in diagnostic laboratories. Opt-resistant (Opt
r
)
S. pneumoniae
isolates have been reported, however, indicating the potential for misidentification of this important pathogen. Point mutations in the
atpC
gene have been associated with the emergence of Opt
r
S. pneumoniae
, but data on the characterization of such atypical variants of
S. pneumoniae
are still limited. The present report describes the results of a polyphasic approach to identifying and characterizing 26 Opt
r
S. pneumoniae
isolates recovered from patients or carriers living in Brazil. Sixteen isolates consisted of heterogeneous populations, and 10 isolates were homogeneously Opt
r
. The isolates had different serotypes and antimicrobial susceptibility profiles. They also presented diverse genetic characteristics, as indicated by pulsed-field gel electrophoresis (PFGE), multilocus variable-number tandem-repeat analysis (MLVA), and
pspA
gene typing. Except for Opt MICs (4- to 64-fold higher among Opt
r
variants), Opt
r
and Opt-susceptible (Opt
s
) subpopulations originating from the same culture had identical characteristics. Sequencing of the
atpC
gene of the Opt
r
variants revealed 13 different nucleotide changes distributed among eight different codons. Changes in codon 49 were the most frequent, suggesting that this might be a hot spot for optochin resistance-conferring mutations. On the other hand, five novel types of mutations in the
atpC
gene (Met13Ile, Gly18Ser, Gly20Ala, Ala31Val, and Ala49Gly) were identified.
In silico
prediction modeling indicated that the
atpC
gene mutations corresponded to alterations in the transmembrane region of the ATPase, leading to a higher hydrophobicity profile in α-helix 1 and to a lower hydrophobicity profile in α-helix 2.
Survey of Culture, GoldenGate Assay, Universal Biosensor Assay, and 16S rRNA Gene Sequencing as Alternative Methods of Bacterial Pathogen Detection
Authors: Lindsay Brianna , Pop Mihai , Antonio Martin , Walker Alan W. , Mai Volker , Ahmed Dilruba , Oundo Joseph , Tamboura Boubou , Panchalingam Sandra , Levine Myron M. , Kotloff Karen , Li Shan , Magder Laurence S. , Paulson Joseph N. , Liu Bo , Ikumapayi Usman , Ebruke Chinelo , Dione Michel , Adeyemi Mitchell , Rance Richard , Stares Mark D. , Ukhanova Maria , Barnes Bret , Lewis Ian , Ahmed Firoz , Alam Meer Taifur , Amin Ruhul , Siddiqui Sabbir , Ochieng John B. , Ouma Emmanuel , Juma Jane , Mailu Eunice , Omore Richard , O'Reilly Ciara E. , Hannis James , Manalili Sheri , DeLeon Jonna , Yasuda Irene , Blyn Lawrence , Ranken Raymond , Li Feng , Housley Roberta , Ecker David J. , Hossain M. Anowar , Breiman Robert F. , Morris J. Glenn , McDaniel Timothy K. , Parkhill Julian , Saha Debasish , Sampath Rangarajan , Stine O. Colin , Nataro James P.
Published: July 2013

Cultivation-based assays combined with PCR or enzyme-linked immunosorbent assay (ELISA)-based methods for finding virulence factors are standard methods for detecting bacterial pathogens in stools; however, with emerging molecular technologies, new methods have become available. The aim of this study was to compare four distinct detection technologies for the identification of pathogens in stools from children under 5 years of age in The Gambia, Mali, Kenya, and Bangladesh. The children were identified, using currently accepted clinical protocols, as either controls or cases with moderate to severe diarrhea. A total of 3,610 stool samples were tested by established clinical culture techniques: 3,179 DNA samples by the Universal Biosensor assay (Ibis Biosciences, Inc.), 1,466 DNA samples by the GoldenGate assay (Illumina), and 1,006 DNA samples by sequencing of 16S rRNA genes. Each method detected different proportions of samples testing positive for each of seven enteric pathogens, enteroaggregative
Escherichia coli
(EAEC), enterotoxigenic
E. coli
(ETEC), enteropathogenic
E. coli
(EPEC),
Shigella
spp.,
Campylobacter jejuni
,
Salmonella enterica
, and
Aeromonas
spp. The comparisons among detection methods included the frequency of positive stool samples and kappa values for making pairwise comparisons. Overall, the standard culture methods detected
Shigella
spp., EPEC, ETEC, and EAEC in smaller proportions of the samples than either of the methods based on detection of the virulence genes from DNA in whole stools. The GoldenGate method revealed the greatest agreement with the other methods. The agreement among methods was higher in cases than in controls. The new molecular technologies have a high potential for highly sensitive identification of bacterial diarrheal pathogens.
Recombination Is Associated with an Outbreak of Novel Highly Pathogenic Porcine Reproductive and Respiratory Syndrome Viruses in China
Authors: Shi Mang , Holmes Edward C. , Brar Manreetpal Singh , Leung Frederick Chi-Ching
Published: July 2013

In 2009 to 2010, there was a marked increase in the number of infections with highly pathogenic porcine reproductive and respiratory syndrome virus (HP-PRRSV) in China. Through phylogenetic analysis, we show that viruses from this outbreak originated from a single recombination event, illustrating the potential importance of this process for disease emergence.
Morphological and Biochemical Characterization of the Membranous Hepatitis C Virus Replication Compartment
Authors: Paul David , Hoppe Simone , Saher Gesine , Krijnse-Locker Jacomine , Bartenschlager Ralf
Published: July 2013

Like all other positive-strand RNA viruses, hepatitis C virus (HCV) induces rearrangements of intracellular membranes that are thought to serve as a scaffold for the assembly of the viral replicase machinery. The most prominent membranous structures present in HCV-infected cells are double-membrane vesicles (DMVs). However, their composition and role in the HCV replication cycle are poorly understood. To gain further insights into the biochemcial properties of HCV-induced membrane alterations, we generated a functional replicon containing a hemagglutinin (HA) affinity tag in nonstructural protein 4B (NS4B), the supposed scaffold protein of the viral replication complex. By using HA-specific affinity purification we isolated NS4B-containing membranes from stable replicon cells. Complementing biochemical and electron microscopy analyses of purified membranes revealed predominantly DMVs, which contained viral proteins NS3 and NS5A as well as enzymatically active viral replicase capable of
de novo
synthesis of HCV RNA. In addition to viral factors, co-opted cellular proteins, such as vesicle-associated membrane protein-associated protein A (VAP-A) and VAP-B, that are crucial for viral RNA replication, as well as cholesterol, a major structural lipid of detergent-resistant membranes, are highly enriched in DMVs. Here we describe the first isolation and biochemical characterization of HCV-induced DMVs. The results obtained underline their central role in the HCV replication cycle and suggest that DMVs are sites of viral RNA replication. The experimental approach described here is a powerful tool to more precisely define the molecular composition of membranous replication factories induced by other positive-strand RNA viruses, such as picorna-, arteri- and coronaviruses.