bluuebunny/crossref_metadata_2025 huggingface dataset:
Successful Application of Innovative Reaming and Completion Technology in Williston Basin Wells
Authors: Scott G. , Smith L. M.
Published: March 2013

In multiple wells in the Williston Basin of North Dakota, introduction of a new reaming tool utilized for dedicated reaming and reaming-while-drilling operations has been introduced successfully in over 140 wells.

This new tool has increased the percentage of packers going to total depth (TD) in a single trip in Williston Basin wells, where it is critical that wellbore condition enables multiple packers to be run and set at TD in a timely fashion in a single trip.

Additionally enhanced packer design, in combination with a better understanding of well bore conditions as well as improved torque and drag reductions, has led to additional field successes. Historically this has not been the case in a number of wells, and information will be provided on certain of those instances.

The reaming tools are currently bring used in reaming-while-drilling scenarios to eliminate the need for a dedicated reamer run in each well; this saves two to three rig days.

These tools can be built as steel or non-magnetic (non-mag) tools; hence, they can be run anywhere in the BHA plus be used to drill out. They reduce spiraling in the well bore, thereby reducing the risk of sticking the liner assembly before reaching TD.

Operators are 100% successful with packers going to TD when using this technology. In addition, current BHA modeling techniques and field use documents that use of the tools presents no significant steerability issues and no loss in penetration rate while still enabling subsequent installation of multiple packers. This proved critical in these North Dakota wells, where the application can require running as many as 35 swell packers to bottom.

Also provided is input on certain packer designs that can be used in combination with these new reaming technologies to improve the chances for going to TD in a single run.

Finally, the paper addresses the economic impact of this reamer application in what can be a half-million dollar operation per well, and notes the on-going progress of reaming-while-drilling efforts to date.
Optimization of Multiple Hydraulically Fractured Horizontal Wells in Unconventional Gas Reservoirs
Authors: Yu Wei , Sepehrnoori Kamy
Published: March 2013

Accurate placement of multiple horizontal wells drilled from the same well pad plays a critical role in the successful economical production from unconventional gas reservoirs. However, there are high cost and uncertainty due to many inestimable and uncertain parameters such as reservoir permeability, porosity, fracture spacing, fracture half-length, fracture conductivity, gas desorption, and existing natural fractures. It is absolutely important to investigate reasonable ranges for these uncertain parameters and evaluate their effects on well performance for the purpose of improving stimulation designs and completion strategies. In this paper, we employ Response Surface Methodology (RSM) to optimize multiple horizontal well placement to maximize Net Present Value (NPV) with numerically modeling multistage hydraulic fractures in combination with economic analysis.

This paper demonstrates the accuracy of numerical modeling of multistage hydraulic fractures for actual Barnett Shale production data by considering the gas desorption effect. Six uncertain parameters, such as permeability, porosity, fracture spacing, fracture half-length, fracture conductivity, and distance between two neighboring wells with a reasonable range based on Barnett Shale information, are used to fit a response surface of NPV as the objective function, and to finally identify the optimum design under conditions of different gas prices based on NPV maximization.

This integrated approach can contribute to obtaining the optimal drainage area around the wells by optimizing well placement and hydraulic fracturing treatment design and provide insight into hydraulic fracture interference between single well and neighboring wells. Also, it can be used to decide whether or not fracture design needs to be adjusted for closer well placement and provide guidance for engineers to modify the design of a hydraulic fracture treatment prior to the actual fracture treatment and to determine the optimal number of horizontal wells for a specified area.
Field and Lab Experience with a Successful Preformed Particle Gel Conformance Control Technology
Authors: Bai Baojun , Wei Mingzhen , Liu Yuzhang
Published: March 2013

Gel treatment is a cost-effective method for oilfield conformance control. Traditionally, in-situ gels formed by the reaction of polymer and crosslinker at reservoirs have been used widely to control conformance. However, a newer trend is to apply preformed particle gels (PPGs) for this purpose because they are formed at surface facilities before injection and they overcome some distinct drawbacks inherent in in-situ gelation systems, such as lack of control over the gelation time, gelling uncertainty due to shear degradation, chromatographic fractionation or change of gelant compositions, and dilution by formation water. PPGs are characterized as having robust gel chemistries and as being highly insensitive to petroleum reservoir environments and interferences. They can resist temperatures up to 120 °C (250 °F) and are compatible with any kind of formation water. In this paper, we describe and discuss our extensive laboratory and field experiences with the widely applied and successful PPG technology. Highlights of illustrative PPG field applications and results are presented. An overview of what over a decade of experience in applying the PPG technology has taught us is discussed. This includes a discussion of classifying and distinguishing conformance problems and treatments, attributes of good candidate wells, requirements that must be met in candidate wells, gel treatment elements that must be implemented successfully to achieve success, and the guidelines as to where PPG conformance treatments are applied most successfully.
Formation Damage Caused by Pipe Dope and Its Remediation
Authors: Mathis Julie , Goretta Emiliano Actis , Saubidet Martin Lopez , Castiñeiras Tomas , Funes Alejandro , Figini Fernando , Wang Xiuli , Economides Michael J.
Published: March 2013

Historically all well strings of casing and tubing have used thread compound or “dope” to enable good connectivity, lubricity and sealability of connections. During the makeup of a connection, excess running compound or dope is squeezed out into the annular space where it can gain access to wellbore fluids and cause formation damage. The innovation of surface technologies and industrial coatings allowed the development of dope-free connections. Dope-free technology can potentially eliminate the use of all dopes in well construction.

Formation damage caused by excess pipe dope is not a recently developed problem but has been overlooked in the past. This, perhaps, is because the problem for production applies to higher formation permeability than the ones studied in this paper. For relatively low-permeability formations whose pore throats are smaller compared to dope particles and therefore the latter do not penetrate the rock matrix, the problem can be mitigated by the flow of reservoir fluids The problem can also be diminished by using solvent treatments (such as toluene or xylene) to help break down and dissolve the dope compounds.

The key benefit of dope-free technology is the prevention of damage to the formation caused by dope entering the formation. Additional benefits include a more reliable and robust connection and a more efficient well site assembly process. Dope-free technology guarantees better downhole performance, minimization of galling and other connection damage as well as immediate savings in the operation by removing a routine and uncontrolled manual operation on the rig floor. Reduction of heavy tubular handling and lifting operations as well as the achievement of a virtual no discharge of effluents are also important benefits.

In this paper, we present the laboratory test results utilizing actual core samples. Results show the creation of a harmful dope suspension that can penetrate and damage the formation. During injection operations this can result in severe damage to the well formation (greater than 99%), while in production operations the damage depends on the reservoir permeability. Within the tested permeability range (<288 md), it is observed that the harmful compounds did not penetrate the rock matrix and, instead, it formed a filter cake that can be removed by reservoir fluid flow while in injection mode.

This paper will demonstrate the benefits of using dope-free pipe connections by quantifying the negative effects of the traditional way of joining connections with dope. Various “thread dopes” are tested, showing the differing potential damage from the dope product used. Production equations using a dope-induced skin effect are also presented, showing the detrimental impact on well performance.
An Experimental Study on Liquid Loading of Vertical and Deviated Gas Wells
Authors: Yuan G. , Pereyra E. , Sarica C. , Sutton Robert P.
Published: March 2013

The main objectives of this experimental study are to explore mechanisms controlling the onset of liquid loading and to investigate effect of well deviation on liquid loading. An experimental study of liquid loading of gas wells has been conducted with air/water flow in a 3-inch pipe at well deviations of 0°, 15° and 30° from vertical. A total of 131 tests have been carried out. Differential pressure gradient and liquid holdup were measured. Flow pattern was observed and videos were captured with a high speed video system. Critical gas velocity which defines the threshold for liquid accumulation in a well (commonly termed liquid loading) has been identified by analyzing different measurements including video captures. Results show different mechanisms for vertical and inclined pipe flows. A minimum pressure gradient criterion can be applied to determine the critical gas velocity. Well deviation angle has an effect on critical gas velocity. Performance analysis for various models has revealed their shortcomings.
3-D Simulation of Carbonate Acidization with HCl: Comparison with Experiments
Authors: Maheshwari P. , Balakotaiah V.
Published: March 2013

Acidization of carbonate rocks is a common practice to reduce the formation damage near wellbore. In this process, an acidic solution is injected to dissolve some of the rock that creates conducting channels called wormholes. These wormholes facilitate the flow of hydrocarbons to the wellbore. In the literature, there are several theoretical and experimental studies performed to understand this process. However, there are very few 3-D numerical studies that can predict quantitatively the experimental results such as the optimum injection rate. An accurate prediction of the optimum acid injection rate is necessary for field scale operations. Therefore, the main objective of this study is to quantitatively predict the experimentally observed acidization curve (amount of acid required to breakthrough versus acid injection rate), so that the validated model could be used for field scale simulations.

In this study, we present 3-D simulation of carbonate acidization with HCl using a two-scale continuum (TSC) model. The model describes the reactive transport at Darcy scale and retains all pore scale physics through structure-property relations. Unlike previous studies, we use a new two-parameter (pore-broadening and pore-connectivity) structure-property relation to describe the change in permeability, pore radius and interfacial area per unit volume with porosity. We predict quantitatively the experimentally observed acidization curve for HCl-limestone system and show the existence of a critical heterogeneity (that corresponds to minimum amount of acid required to breakthrough). We also present scaling criteria to estimate the wormhole tip diameter and optimum acid injection rate, for vuggy and non-vuggy carbonates. Finally, we present the flow dynamics of acid inside the wormhole.
Production and Injection Monitoring and Surveillance
Authors: Agudelo O. , Amaya M. , Nunez G. , Volante M. , Escalona C.
Published: March 2013

The Casabe Technology Alliance between Ecopetrol and Schlumberger started its operation in 2004 in Casabe field. The field came originally into production several decades ago and by 2004 was producing close to 5,000 BOPD.

The alliance has since redevelopment the field with an aggressive strategy to increase Oil production through selective water injection for secondary recovery. The redevelopment considered a significant increase of production and selective injector wells, something that poses a challenge in terms of injection and production data handling, engineering worklfows for better decision making.

During the time Casabe Project began complicate by the workover, drilling and waterflooding activities that are performing for the alliance beside the complicate mature reservoir condition and the original date base, that was un integrated, with duplicity data, without control quality, storage limit, etc. Where at the end of the days the engineers were spending more than 80% of time, searching date and 20% of time integrating and analyzing information to solve field problem and make decision.

For that reason Casabe alliance decide creation a project that helps integrate different components to reduced engineer time to analysis field data and make appropriate and quickly decision.

This project key implementation stages included:

Component 1: Data Management ■ Data consolidation and creation of one unique data source of information for Casabe's asset historical production. Component 2: Production business processes and mapping of information flows. ■ Analyze and document the current injection / production process, to identify improvements related to data management Component 3: Production information and engineering workflows management ■ Integrate System→ Identify workflows based on reservoir surveillance. ■ Data visualization and alarms generation. ■ Link operational database with the other applications, like as: Reservoir Monitoring and Analysis. ■ Ensure data quality for the follow up and analysis.
Application of Mass Balance and Transient Flow Modeling for Leak Detection in Liquid Pipelines
Authors: Rivas Karent V , Civan Faruk
Published: March 2013

Effective methodologies implementing proper flow hydraulics simulation approaches are presented for accurate leak detection in natural gas liquid (NGL) pipelines under steady- and transient-state flow conditions based on mass and force balance principles and head and flow measurements taken at pipeline end-points. Leak detection curves are generated using a process simulation package under steady-state operation conditions for systems with prescribed fluid compositions, pipeline characteristics, and instrumentation accuracy. Real-time transient-state leak detection along a pipeline is accomplished by simulation of pipeline fluid conditions with a proper flow model. Typical transient-state flow episodes are demonstrated for pump-start up and valve closing cases. Real pipeline data are facilitated in the leak detection model by implementing a time-marching algorithm. Deviations of patterns for measured inlet and outlet flow conditions and heads are facilitated for detection of occurrence and locations of leaks. It is shown that the response time depends on the leak location and has the lowest value for leaks occurring near the pipeline middle-point, leak location can be predicted based on the time required for detection of a discrepancy, and estimation of leak location is more difficult when the mass of pipeline fluid and hence resistance to flow increase. Proposed approaches can be instrumental for critical review and assessment of the physical characteristics, limitations, capabilities, and instrumentation adequacy of pipelines for safe operation and proper selection of effective leak detection technologies and instrumentation upgrades with improved response time and accuracy required for pinpointing of leak locations and estimation of leak sizes.
Intravenous Gammaglobulin Inhibits Encephalitogenic Potential of Pathogenic T Cells and Interferes with their Trafficking to the Central Nervous System, Implicating Sphingosine-1 Phosphate Receptor 1–Mammalian Target of Rapamycin Axis
Authors: Othy Shivashankar , Hegde Pushpa , Topçu Selma , Sharma Meenu , Maddur Mohan S. , Lacroix-Desmazes Sebastien , Bayry Jagadeesh , Kaveri Srini V.
Published: March 2013

Despite an increasing use of high-dose therapy of i.v. gammaglobulin (IVIg) in the treatment of various T cell– and Ab-mediated inflammatory and autoimmune diseases, comprehension of the mechanisms underlying its therapeutic benefit has remained a major challenge. Particularly, the effect of IVIg in T cell–mediated autoimmune conditions remains unexplored. Using an actively induced experimental autoimmune encephalomyelitis model, a T cell–mediated autoimmune condition, we demonstrate that IVIg inhibits the differentiation of naive CD4 T cells into encephalitogenic subsets (Th1 and Th17 cells) and concomitantly induces an expansion of Foxp3+ regulatory T cells. Further, IVIg renders effector T cells less pathogenic by decreasing the expression of encephalitogenic molecular players like GM-CSF and podoplanin. Intriguingly and contrary to the current arguments, the inhibitory FcγRIIB is dispensable for IVIg-mediated reciprocal modulation of effector and regulatory CD4 subsets. Additionally, F(ab′)2 fragments also retained this function of IVIg. IVIg or F(ab′)2 fragments decrease the sphingosine-1 phosphate receptor on CD4 cells, thus sequestering these cells in the draining lymph nodes and decreasing their infiltration into the CNS. Our study reveals a novel role of Igs in the modulation of polarization and trafficking of T lymphocytes, accounting for the observed beneficial effect in IVIg therapy.
Inflammatory Response of Mast Cells during Influenza A Virus Infection Is Mediated by Active Infection and RIG-I Signaling
Authors: Graham Amy C. , Hilmer Kimberly M. , Zickovich Julianne M. , Obar Joshua J.
Published: March 2013

Influenza A virus (IAV) is a major respiratory pathogen of both humans and animals. The lung is protected from pathogens by alveolar epithelial cells, tissue-resident alveolar macrophages, dendritic cells, and mast cells. The role of alveolar epithelial cells, endothelial cells, and alveolar macrophages during IAV infection has been studied previously. In this study, we address the role of mast cells during IAV infection. Respiratory infection with A/WSN/33 causes significant disease and immunopathology in C57BL/6 mice but not in B6.Cg-KitW-sh mice, which lack mast cells. During in vitro coculture, A/WSN/33 caused mast cells to release histamine, secrete cytokines and chemokines, and produce leukotrienes. Moreover, when mast cells were infected with IAV, the virus did not replicate within mast cells. Importantly, human H1N1, H3N2, and influenza B virus isolates also could activate mast cells in vitro. Mast cell production of cytokines and chemokines occurs in a RIG-I/MAVS–dependent mechanism; in contrast, histamine production occurred through a RIG-I/MAVS–independent mechanism. Our data highlight that, following IAV infection, the response of mast cells is controlled by multiple receptors. In conclusion, we identified a unique inflammatory cascade activated during IAV infection that could potentially be targeted to limit morbidity following IAV infection.
Comparing Treatment Options of Pterygium: Limbal Sliding Flap Transplantation, Primary Closing, and Amniotic Membrane Grafting
Authors: Kurna Sevda Aydin , Altun Ahmet , Aksu Bahtinur , Kurna Riza , Sengor Tomris
Published: March 2013

Purpose

To compare 3 surgical treatment options of pterygium: limbal sliding flap transplantation, primary closing, and amniotic membrane grafting methods.

Methods

Seventy-five patients with primary pterygium were included in the study Snellen visual acuity measurement, grading pterygium, slit-lamp examination, keratometry, and anterior segment photography were performed preoperatively. Twenty-eight eyes of 28 patients (group 1) underwent limbal-conjunctival sliding flap transplantation, 22 eyes of 22 patients (group 2) underwent amniotic membrane grafting, and 25 eyes of 25 patients (group 3) underwent primary closing surgery The patients were followed up on the first day and the first week after surgery and then at months 1, 3, 6, and 12.

Results

The mean size of the pterygium preoperatively was 3.58 ± 1.1 mm in group 1, 3.95 ± 0.90 mm in group 2, and 3.5 ± 0.87 mm in group 3. The mean follow-up time was 15.07 ± 13.8 months in group 1, 20.2 ± 6.7 months in group 2, and 28.04 ± 9.9 months in group 3. Grade 4 corneal recurrence rate in follow-up was 7.1% in group 1, 27.3% in group 2, and 56% in group 3 (p = 0.00). Mean recurrence times were 4.0 ± 1.7, 4.4 ± 3.3, and 4.4 ± 3.6 months according to groups 1, 2, and 3 (p = 0.963). After the surgery, corneal astigmatism decreased and keratometric values increased significantly in all the groups with no statistically significant difference between the groups (p>0.05).

Conclusions

Limbal-conjunctival sliding flap transplantation is an efficient method to manage primary pterygium. It may be a safe and effective initial treatment option to reduce risk of recurrence and postoperative complications of pterygium surgery.
Diagnosis of Periprosthetic Joint Infections in Clinical Practice
Authors: Sendi Parham , Zimmerli Werner
Published: March 2013

The diagnosis of a periprosthetic joint infection (PJI) can be challenging, either because of the variable clinical presentation or because of previous antimicrobial treatment interfering with the detection of the pathogen. In recent years, various means to diagnose PJI have been analyzed. These include invasive and non-invasive laboratory tests, imaging procedures, and novel techniques such as sonication of implants and the use of molecular microbiology. In this review, both established and novel diagnostic procedures are presented. An algorithm for detecting PJI in patients with acute and chronic symptoms is proposed.
Podocalyxin Is a Glycoprotein Ligand of the Human Pluripotent Stem Cell-Specific Probe rBC2LCN
Authors: Tateno Hiroaki , Matsushima Asako , Hiemori Keiko , Onuma Yasuko , Ito Yuzuru , Hasehira Kayo , Nishimura Ken , Ohtaka Manami , Takayasu Satoko , Nakanishi Mahito , Ikehara Yuzuru , Nakanishi Mio , Ohnuma Kiyoshi , Chan Techuan , Toyoda Masashi , Akutsu Hidenori , Umezawa Akihiro , Asashima Makoto , Hirabayashi Jun
Published: March 2013

In comprehensive glycome analysis with a high-density lectin microarray, we have previously shown that the recombinant N-terminal domain of the lectin BC2L-C from Burkholderia cenocepacia (rBC2LCN) binds exclusively to undifferentiated human induced pluripotent stem (iPS) cells and embryonic stem (ES) cells but not to differentiated somatic cells. Here we demonstrate that podocalyxin, a heavily glycosylated type 1 transmembrane protein, is a glycoprotein ligand of rBC2LCN on human iPS cells and ES cells. When analyzed by DNA microarray, podocalyxin was found to be highly expressed in both iPS cells and ES cells. Western and lectin blotting revealed that rBC2LCN binds to podocalyxin with a high molecular weight of more than 240 kDa in undifferentiated iPS cells of six different origins and four ES cell lines, but no binding was observed in either differentiated mouse feeder cells or somatic cells. The specific binding of rBC2LCN to podocalyxin prepared from a large set of iPS cells (138 types) and ES cells (15 types) was also confirmed using a high-throughput antibody-overlay lectin microarray. Alkaline digestion greatly reduced the binding of rBC2LCN to podocalyxin, indicating that the major glycan ligands of rBC2LCN are presented on O-glycans. Furthermore, rBC2LCN was found to exhibit significant affinity to a branched O-glycan comprising an H type 3 structure (Ka, 2.5 × 104 M−1) prepared from human 201B7 iPS cells, indicating that H type 3 is a most probable potential pluripotency marker. We conclude that podocalyxin is a glycoprotein ligand of rBC2LCN on human iPS cells and ES cells.
The Addition of ArSSAr to Alkenes: The Implications of a Cationic Chain Mechanism Initiated by Electrogenerated ArS(ArSSAr)+
Authors: Matsumoto Kouichi , Sanada Tomonari , Shimazaki Hayato , Shimada Kazuaki , Hagiwara Shino , Fujie Shunsuke , Ashikari Yosuke , Suga Seiji , Kashimura Shigenori , Yoshida Jun‐ichi
Published: March 2013

The addition reactions of diaryl disulfides (ArSSAr) to alkenes and alkynes were achieved with a catalytic amount of an arylbis(arylthio)sulfonium ion (ArS(ArSSAr)+), which was generated and accumulated by low‐temperature electrolysis of ArSSAr, to give the corresponding diarylthiolated products. The electrolysis of a mixture of ArSSAr and an alkene with a catalytic amount of electricity was also effective to drive the reactions. A cation chain mechanism mediated by ArS(ArSSAr)+ as a chain carrier is suggested.
Reproductive Parameters of Female Macaca mulatta tcheliensis in the Temperate Forest of Mount Taihangshan, Jiyuan, China
Authors: TIAN JUN‐DONG , WANG ZHEN‐LONG , LU JI‐QI , WANG BAI‐SHI , CHEN JU‐RONG
Published: March 2013

The remaining population of Macaca mulatta tcheliensis, approximately 3,000 individuals, is currently confined to the southern region of Mount Taihangshan, northern China. Using data collected from February 2003 to November 2012, we examined female reproductive characteristics in a seasonally food supplemented free‐ranging group of M. m. tcheliensis (Wangwu 1, WW‐1), inhabiting the Taishangshan Macaque National Nature Reserve (TMNNR), Jiyuan, China. We tested a series of predictions regarding the degree to which M. m. tcheliensis is best considered as a “strict income breeder,” a “relaxed income breeder” or a “capital breeder.” This group was comprised 18 adult females who produced 64 infants over the 10‐year study period. In our study group (WW‐1) adult female macaques gave birth to an average of 0.71 ± 0.26 infants per year. Infant mortality was 13.4 ± 19.3%. The age at first birth for mothers was 4.9 ± 0.5 years old. The mean inter‐birth interval (IBI) was 15.4 ± 4.9 months. Based on the fact M. m. tcheliensis is a strictly seasonal breeder (76.6% of births occurred between April and May) with infants born during a time of the year when food availability appears to be high, and that their IBI is intermediate in length compared with other macaque populations, our results suggest that M. m. tcheliensis follows a birth pattern most consistent with a “relaxed income breeder” strategy. Am. J. Primatol. 75:605‐612, 2013. © 2013 Wiley Periodicals, Inc.
Improved characterization of the plus fraction for wax precipitation from petroleum fluids
Authors: Wang Wei , Duan Jimiao , Liu Huishu , Zhang Siqi , Gong Jing
Published: March 2013

Wax formation is a serious problem in the gas and oil industry because it can block oil production facilities and transportation pipelines. It is, therefore, of great importance to have a reliable tool to predict wax formation under various operational conditions. The hydrocarbon plus fractions that comprise a significant portion of naturally occurring hydrocarbon fluids create major problems when determining the thermodynamic properties and the volumetric behavior of these fluids by equations of state. In this work, an effort has been made to further improve the characterization of the plus fraction, splitting the plus fraction into a single carbon number (SCN) and generating the mole fraction, on the basis of the relationship between the three‐parameter gamma distribution, experimental molar fraction, molecular weight, and SCN data obtained from literature and industrial contact. The three‐parameter gamma distribution is used to fit the trend of the computational analysis. The method has been used to predict wax appearance temperatures (WATs) for a great number of systems and to compare with some methods generated previously. The average deviation of the calculated WAT is 1.47 K for the system with the experimental data. There are some correlations generated to calculate the physical–chemical properties as a function of SCN. Those correlations have been originally developed to work with light oil. The developed approach, along with some of the correlations, is tested for calculating WAT to identify the applicability in this work. © 2013 Curtin University of Technology and John Wiley & Sons, Ltd.
The Effects of Shipping on Early Pregnancy in Laboratory Rats
Authors: Pritchett‐Corning Kathleen R. , Clifford Charles B. , Festing Michael F. W.
Published: March 2013

Although rats in various stages of pregnancy are routinely shipped by vendors, the effects of shipping on pregnancy outcomes have not been reported. This study examined the effects of shipping rats 1 day after mating. Two outbred stocks, (Crl:CD(SD), Crl:WI(Han)) and one inbred strain (F344/Crl) of rats (n = 300/strain) were mated in a vendor barrier room at 3‐month intervals five times, and either shipped the next day (total time in transit ∼24 hr) or held in the room of origin until parturition. The pregnancy status, length of gestation, number of pups born per female, sex ratio of pups born, and neonatal mortality were compared between transported and nontransported rats. These pregnancy and litter parameters were also compared among strains and examined for seasonality; no seasonal effects were observed. Neonatal mortality was negligible at less than 2% in any of the groups. All sex ratios were normal. Transportation affected pregnancy rates only in the F344/Crl, in which 81.8% of the nontransported versus 70% of the transported rats had pups (p = 0.025). Overall, slightly fewer transported rats were pregnant, but they had larger litters (10.08 compared with 9.68, p = 0.02, pooling across all three strains) so produced the same numbers of pups. A total of 77 ± 8% of transported rats had gestation periods of 22 days or more compared with only 52 ± 10% in the nontransported rats. The reason for larger litters in transported females is unclear. Longer gestation in transported females may be due to facultative embryonic diapause, which might have implications for reproductive toxicology.
A fluorescent peptoid pH‐sensor
Authors: Fuller Amelia A. , Holmes Courtney A. , Seidl Frederick J.
Published: March 2013

Peptoids, N‐substituted glycine oligomers, can adopt stable three‐dimensional structures and have found diverse application as peptide surrogates and as nanomaterials. In this report, we have expanded peptoid function to include pH sensing by coupling pH‐induced peptoid conformational changes with fluorescence intensity changes. We report two new peptoids (2 and 3) that comprise carboxylic‐acid functionalized side chains and undergo conformational rearrangement in response to pH. Peptoids 2 and 3 are also labeled at one side‐chain with an environmentally sensitive fluorophore, 4‐N,N‐dimethylamino‐1,8‐naphthalimide (4DMN). The fluorescence intensity of 2 varies 24‐fold over the pH range studied. These spectroscopic properties make 2 a sensitive, biocompatible pH sensor. © 2013 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 100: 380–386, 2013.
New insights into the roles of sulfated glycosaminoglycans in islet amyloid polypeptide amyloidogenesis and cytotoxicity
Authors: De Carufel Carole Anne , Nguyen Phuong Trang , Sahnouni Sabrina , Bourgault Steve
Published: March 2013

Glycosaminoglycans (GAGs) are found in association with virtually all extracellular protein deposits related to amyloid diseases. Particularly, GAGs were shown to enhance fibrillogenesis of the islet amyloid polypeptide (IAPP), a peptide hormone whose aggregation is associated with Type‐II diabetes pathogenesis. However, the exact molecular mechanism by which GAGs enhance IAPP amyloidogenesis remains unclear as well as the implications of cell surface GAGs in IAPP‐mediated cytotoxicity. The aim of this study was to gain conformational and thermodynamics insights about GAGs‐IAPP interactions as a function of IAPP protonation state and buffer ionic strength as well as to explore the roles of cell surface GAGs in IAPP cytotoxicity. Isothermal titration calorimetry revealed that protonation of residue His18 increases the binding affinity of IAPP towards heparin and, in turn, strongly stimulates fibrillogenesis. Interaction of IAPP with heparin induces a random coil to helix conformational conversion and the helical intermediates could be on‐pathway to amyloid fibrils formation. Using rat beta‐cells INS‐1 that were enzymatically treated with GAG lyases and a CHO cell line that is deficient in the biosynthesis of GAGs, we observed that the lack of GAGs at the plasma membrane does not prevent IAPP‐induced toxicity, whereas the presence of soluble heparin in the cell media inhibits IAPP cytotoxicity. Overall, this study reinforces the postulate that sulfated GAGs are actively implicated in IAPP amyloidogenic process in vivo, where they could play a protective role by interacting with cytotoxic species and converting them into less culprit amyloid fibrils. © 2013 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 100: 645–655, 2013.
Parahydrogen‐Induced Polarization Transfer to 19F in Perfluorocarbons for 19F NMR Spectroscopy and MRI
Authors: Plaumann Markus , Bommerich Ute , Trantzschel Thomas , Lego Denise , Dillenberger Sonja , Sauer Grit , Bargon Joachim , Buntkowsky Gerd , Bernarding Johannes
Published: March 2013

Fluorinated substances are important in chemistry, industry, and the life sciences. In a new approach, parahydrogen‐induced polarization (PHIP) is applied to enhance 19F MR signals of (perfluoro‐n‐hexyl)ethene and (perfluoro‐n‐hexyl)ethane. Unexpectedly, the end‐standing CF3 group exhibits the highest amount of polarization despite the negligible coupling to the added protons. To clarify this non‐intuitive distribution of polarization, signal enhancements in deuterated chloroform and acetone were compared and 19F–19F NOESY spectra, as well as 19F T1 values were measured by NMR spectroscopy. By using the well separated and enhanced signal of the CF3 group, first 19F MR images of hyperpolarized linear semifluorinated alkenes were recorded.
Examination of the Degreasing of Metal Surfaces by the Use of a Plasma Torch
Authors: Burm K.T.A.L.
Published: March 2013

Metal surfaces can be degreased via a combustion reaction upon the metal surface by the use of a plasma torch jet. The required energy and the reaction rate of the combustion reaction are examined here. It turns out that the reaction rate can limit the cleaning performance. In such case, the cleaning performance is not improved at higher powers. It is suggested to increase the temperature at which combustion takes place such that the cleaning performance can improve again at higher powers. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Model for the Error Field Effect on Resistive Wall Modes
Authors: Miron I. G.
Published: March 2013

A semianalytic multimode model that includes the instantaneous influence of a static error field on the resistive wall mode (RWM) is presented. The asymptotic behavior of the RWM as the marginal stability is approached, including the influence of the error field, is discussed. The influence of neighboring modes on the central harmonic modes is explored, allowing a less destabilizing error field spectrum to be proposed. The model has been applied to a plasma surrounded by a HBT‐EP tokamak type feedback system. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Resolving cell lineage contributions to the ventricular conduction system with a Cx40‐GFP allele: A dual contribution of the first and second heart fields
Authors: Miquerol Lucile , Bellon Anaïs , Moreno Natividad , Beyer Sabrina , Meilhac Sigolène M. , Buckingham Margaret , Franco Diego , Kelly Robert G.
Published: March 2013

Background: The ventricular conduction system (VCS) coordinates the heartbeat and is composed of central components (the atrioventricular node, bundle, and right and left bundle branches) and a peripheral Purkinje fiber network. Conductive myocytes develop from common progenitor cells with working myocytes in a bimodal process of lineage restriction followed by limited outgrowth. The lineage relationship between progenitor cells giving rise to different components of the VCS is unclear. Results: Cell lineage contributions to different components of the VCS were analysed by a combination of retrospective clonal analysis, regionalized transgene expression studies, and genetic tracing experiments using Connexin40‐GFP mice that precisely delineate the VCS. Analysis of a library of hearts containing rare large clusters of clonally related myocytes identifies two VCS lineages encompassing either the right Purkinje fiber network or left bundle branch. Both lineages contribute to the atrioventricular bundle and right bundle branch that segregate early from working myocytes. Right and left VCS lineages share the transcriptional program of the respective ventricular working myocytes and genetic tracing experiments discount alternate progenitor cell contributions to the VCS. Conclusions: The mammalian VCS is comprised of cells derived from two lineages, supporting a dual contribution of first and second heart field progenitor cells. Developmental Dynamics 242:665–677, 2013. © 2013 Wiley Periodicals, Inc.
Fish (Spinibarbus hollandi) dynamics in relation to changing hydrological conditions: physical modelling, individual‐based numerical modelling, and case study
Authors: Han Rui , Chen Qiuwen , Blanckaert Koen , Li Weiming , Li Ruonan
Published: March 2013

The paper reports the development of an individual‐based fish dynamics model, of which the key components are the rules for the movement of individual fish and the definition of the habitat suitability. The distribution of the fish mainly depends on the flow conditions (velocity, depth, substrate) and life cycle of the fish. A major contribution is the refinement of the rules for fish movement, based on laboratory experiments under volitional swimming conditions, which also provided the ranges of preferential velocities and substrate size for the target fish, Spinibarbus hollandi. Moreover, they provided data on the fish trajectories and distribution patterns that allowed for validation of the movement rules. The validated fish dynamics model was applied to investigate the effect of discharge increase during the dry season by means of reservoir operation in the Lijiang River, which was the subject of field investigations in 2007 and 2008. The model results indicated that reservoir operation leads to an increase of fish biomass. According to the fish movement rules, fish cannot always escape from riverbed regions that dry during decreasing discharge events, which causes them to be trapped and die. Reservoir operation decreases the area of dry riverbed and reduces the travel distance for fish to escape from dry regions. Critical advantages of the individual fish model over global models defined on the population level are that they can account for the time that the fish needs to reach a region of suitable habitat and for the spatial pattern of suitable zones and their connectivity. Copyright © 2013 John Wiley & Sons, Ltd.
A robust 2D shallow water model for solving flow over complex topography using homogenous flux method
Authors: Guan M. , Wright N.G. , Sleigh P.A.
Published: March 2013

A robust Godunov‐type numerical scheme solver is proposed for solving 2D SWEs and is applied to simulate flow over complex topography with wetting and drying. In reality, the topography is usually complex and irregular; therefore, to avoid the numerical errors generated by such features, a Homogenous Flux Method is used to handle the bed slope term in the SWEs. The method treats the bed slope term as a flux to be incorporated into the flux gradient and so maintains the balance between the two in a Godunov‐type shock‐capturing scheme. The main advantages of the method are: first, it is simple and easy to implement; second, numerical experiments demonstrate that it can handle discontinuous or vertical bed topography without any special treatment and third, it is applicable to both steady and unsteady flows. It is demonstrated how the approach set out here can be applied to the nonlinear hyperbolic system of the SWEs. The two‐dimensional hyperbolic system is then solved by use of a second‐order total‐variation‐diminishing version of the weighted average flux method in conjunction with a Harten‐Lax‐van Leer‐Contract approximate Riemann solver incorporating the new flux gradient term. Several benchmark tests are presented to validate the model and the approach is verified against experimental measurements from the European Union Concerted Action on Dam Break Modelling project. These show very good agreement. Finally, the method is applied to a volcano‐induced outburst flood over an initially dry channel with complex irregular topography to demonstrate the technique's capability in simulating a real flood. Copyright © 2013 John Wiley & Sons, Ltd.
Effect of CO2 hydrate formation on seismic wave velocities of fine‐grained sediments
Authors: Kim Hak‐Sung , Cho Gye‐Chun , Kwon Tae‐Hyuk
Published: March 2013

This study examines the effect of gas hydrate formation on seismic wave velocities of fine‐grained sediments. Synthesis of gas hydrates in fine‐grained sediments has proved to be challenging, and how hydrate formation would affect the seismic wave velocities and stiffness of clay‐rich sediments has not yet been fully understood. In this study, CO2 hydrate was synthesized in remolded and partially water‐saturated clayey silt sediments that were originally cored from a hydrate occurrence region in the Ulleung Basin, East Sea, offshore Korea. After achieving excess water conditions, compressional wave and shear wave velocities were measured for different hydrate saturations and under different vertical effective stresses. The results reveal that the compressional wave velocity VP and shear wave velocity VS increase, and the stress‐dependency of VP and VS decreases as the hydrate saturation SH increases from 0% to ~60%. In particular, the VS‐SH trend lies between the grain‐cementing model and the load‐bearing model, suggesting that gas hydrate formation in clayey silt sediments causes weak cementation from a hydrate saturation less than ~28%. The weak cementation in fine‐grained sediments can be explained by the breakage of hydrate bonds that are cementing grains during sediment compression and/or the innate weakness in bonding between hydrate crystals and fine mineral grains owing to the presence of unfrozen water films on clay mineral surfaces. In addition, it is found that at low SH, the cementation effect on VP is masked by the high stiffness of pore‐filling phases, but it becomes pronounced at SH greater than 47%.
Small‐scale heterogeneities in the oceanic lithosphere inferred from guided waves
Authors: Shito Azusa , Suetsugu Daisuke , Furumura Takashi , Sugioka Hiroko , Ito Aki
Published: March 2013

We analyze seismic waveforms from deep‐focus earthquakes occurring in the subducting slab beneath Japan, recorded by broadband ocean bottom seismometers (BBOBSs) installed on the northwestern Pacific Ocean seafloor. The data reveal waveforms with a low‐frequency direct P onset, followed by large‐amplitude, high‐frequency, long‐duration Po and So waves. From the analysis of the BBOBS records and a numerical finite‐difference method simulation of seismic wave propagation, we elucidate the generation and propagation processes of such guided waves. We demonstrate that the low‐frequency direct P and S waves propagate in the asthenosphere and that the following high‐frequency, long‐duration Po and So waves are developed by multiple forward scattering of P and S waves. The scattering occurs due to laterally elongated heterogeneities in both the subducting and horizontal parts of the oceanic lithosphere, with the apparent velocities (Vp = 8.1 km/s, Vs = 4.6 km/s) being close to the velocities of oceanic lithosphere.
The response of atmospheric nitrous oxide to climate variations during the last glacial period
Authors: Schilt Adrian , Baumgartner Matthias , Eicher Olivier , Chappellaz Jérôme , Schwander Jakob , Fischer Hubertus , Stocker Thomas F.
Published: March 2013

Detailed insight into natural variations of the greenhouse gas nitrous oxide (N2O) in response to changes in the Earth's climate system is provided by new measurements along the ice core of the North Greenland Ice Core Project (NGRIP). The presented record reaches from the early Holocene back into the previous interglacial with a mean time resolution of about 75years. Between 11 and 120kyrBP, atmospheric N2O concentrations react substantially to the last glacial‐interglacial transition (Termination 1) and millennial time scale climate variations of the last glacial period. For long‐lasting Dansgaard/Oeschger (DO) events, the N2O increase precedes Greenland temperature change by several hundred years with an increase rate of about 0.8–1.3ppbv/century, which accelerates to about 3.8–10.7ppbv/century at the time of the rapid warming in Greenland. Within each bundle of DO events, the new record further reveals particularly low N2O concentrations at the approximate time of Heinrich events. This suggests that the response of marine and/or terrestrial N2O emissions on a global scale are different for stadials with and without Heinrich events.
Global modes of climate variability
Authors: de Viron O. , Dickey J. O. , Ghil M.
Published: March 2013

The atmosphere, hydrosphere, and cryosphere form a fully coupled climate system. This system exhibits a number of large‒scale phenomena, such as the El Niño–Southern Oscillation, the Asian Monsoon, the North Atlantic Oscillation, and the Madden‒Julian Oscillation. While these modes of variability are not exactly periodic, they are oscillatory in character, and their state is monitored using so‒called climate indices. Each of these scalar indices is a combination of several climate variables. Here we use a comprehensive set of 25 climate indices for time intervals that range between 1948 and 2011 and estimate an optimal set of lags between these indices to maximize their correlation. We show that most of the index pairs drawn from this set present a significant correlation on interannual time scales. It is also shown that on average, about two thirds of the total variability in each index can be described by using only the four leading principal components of the entire set of lagged indices. Our index set's leading orthogonal modes exhibit several interannual frequencies and capture separately variability associated with the North Atlantic and the North Pacific. These modes are associated, in turn, with large‒scale variations of sea surface temperatures.
Kawasaki disease and ENSO‐driven wind circulation
Authors: Ballester Joan , Burns Jane C. , Cayan Dan , Nakamura Yosikazu , Uehara Ritei , Rodó Xavier
Published: March 2013

Kawasaki disease (KD) is the most common cause of acquired heart disease in children worldwide. Recently, a climatological study suggested that KD may be triggered by a windborne agent traveling across the north Pacific through the westerly wind flow prevailing at midlatitudes. Here we use KD records to describe the association between enhanced disease activity on opposite sides of the basin and different phases of the El Niño‐Southern Oscillation (ENSO) phenomenon, via the linkage to these tropospheric winds. Results show that years with higher‐than‐normal KD cases in Japan preferentially occur during either El Niño Modoki or La Niña conditions, while in San Diego during the mature phase of El Niño or La Niña events. Given that ENSO offers a degree of predictability at lead times of 6 months, these modulations suggest that seasonal predictions of KD could be used to alert clinicians to periods of increased disease activity.