bluuebunny/crossref_metadata_2025 huggingface dataset:
Water skiing biomechanics: a study of advanced skiers
Authors: Bray-Miners Jordan , Runciman R John , Monteith Gabrielle
Published: June 2012

Six advanced slalom skiers were recruited to test four different ski designs over the summer months of 2010. An axial load transducer, boat global positioning system and skier global positioning system were used to calculate rope load and velocity for the skier during the deep water start and cutting portion of a slalom run. The methodology was designed where possible to reduce the uncontrollable factors that present themselves in the natural environment of slalom water skiing. There was statistical evidence to suggest that there was a difference in the average peak rope load produced between the skis during cutting. The typical average peak rope load and skier velocity, for an advanced skier, during the cutting portion of a ski run is in the range of 1.41–2.74 times body weight. The instrumentation was unable to provide enough evidence to suggest that there was a difference in the peak skier velocity during cutting or peak rope load during deep water starts. The typical average peak skier velocity while cutting, and rope load, during a deep water start, for an advanced skier, was in the range of 114–135% of boat speed and 1.74–2.74 times body weight. Furthermore, there was a statistical difference in the overall performance of the skiers participating in the study. The analysis techniques utilized in this study have the potential of providing more quantitative performance evaluation data than is currently available for water ski product development and coaching, and should prove useful for future performance-driven development and coaching.
Bruton tyrosine kinase inhibition is a novel therapeutic strategy targeting tumor in the bone marrow microenvironment in multiple myeloma
Authors: Tai Yu-Tzu , Chang Betty Y. , Kong Sun-Young , Fulciniti Mariateresa , Yang Guang , Calle Yolanda , Hu Yiguo , Lin Jianhong , Zhao Jian-Jun , Cagnetta Antonia , Cea Michele , Sellitto Michael A. , Zhong Mike Y. , Wang Qiuju , Acharya Chirag , Carrasco Daniel R. , Buggy Joseph J. , Elias Laurence , Treon Steven P. , Matsui William , Richardson Paul , Munshi Nikhil C. , Anderson Kenneth C.
Published: June 2012

Bruton tyrosine kinase (Btk) has a well-defined role in B-cell development, whereas its expression in osteoclasts (OCs) further suggests a role in osteoclastogenesis. Here we investigated effects of PCI-32765, an oral and selective Btk inhibitor, on osteoclastogenesis as well as on multiple myeloma (MM) growth within the BM microenvironment. PCI-32765 blocked RANKL/M-CSF–induced phosphorylation of Btk and downstream PLC-γ2 in OCs, resulting in diminished TRAP5b (ED50 = 17nM) and bone resorption activity. PCI-32765 also inhibited secretion of multiple cytokines and chemokines from OC and BM stromal cell cultures from both normal donors (ED50 = 0.5nM) and MM patients. It decreased SDF-1–induced migration of MM cells, and down-regulated MIP1-α/CCL3 in MM cells. It also blocked MM cell growth and survival triggered by IL-6 or coculture with BM stromal cells or OCs in vitro. Importantly, PCI-32765 treatment significantly inhibits in vivo MM cell growth (P < .03) and MM cell–induced osteolysis of implanted human bone chips in SCID mice. Moreover, PCI-32765 prevents in vitro colony formation by stem-like cells from MM patients. Together, these results delineate functional sequelae of Btk activation mediating osteolysis and growth of MM cells, supporting evaluation of PCI-32765 as a novel therapeutic in MM.
Implementation of ICD-10 in Canada: how has it impacted coded hospital discharge data?
Authors: Walker Robin L , Hennessy Deirdre A , Johansen Helen , Sambell Christie , Lix Lisa , Quan Hude
Published: June 2012

Background

The purpose of this study was to assess whether or not the change in coding classification had an impact on diagnosis and comorbidity coding in hospital discharge data across Canadian provinces.

Methods

This study examined eight years (fiscal years 1998 to 2005) of hospital records from the Hospital Person-Oriented Information database (HPOI) derived from the Canadian national Discharge Abstract Database. The average number of coded diagnoses per hospital visit was examined from 1998 to 2005 for provinces that switched from International Classifications of Disease 9th version (ICD-9-CM) to ICD-10-CA during this period. The average numbers of type 2 and 3 diagnoses were also described. The prevalence of the Charlson comorbidities and distribution of the Charlson score one year before and one year after ICD-10 implementation for each of the 9 provinces was examined. The prevalence of at least one of the seventeen Charlson comorbidities one year before and one year after ICD-10 implementation were described by hospital characteristics (teaching/non-teaching, urban/rural, volume of patients).

Results

Nine Canadian provinces switched from ICD-9-CM to ICD-I0-CA over a 6 year period starting in 2001. The average number of diagnoses coded per hospital visit for all code types over the study period was 2.58. After implementation of ICD-10-CA a decrease in the number of diagnoses coded was found in four provinces whereas the number of diagnoses coded in the other five provinces remained similar. The prevalence of at least one of the seventeen Charlson conditions remained relatively stable after ICD-10 was implemented, as did the distribution of the Charlson score. When stratified by hospital characteristics, the prevalence of at least one Charlson condition decreased after ICD-10-CA implementation, particularly for low volume hospitals.

Conclusion

In conclusion, implementation of ICD-10-CA in Canadian provinces did not substantially change coding practices, but there was some coding variation in the average number of diagnoses per hospital visit across provinces.
Effects of high-fat diet and physical activity on pyruvate dehydrogenase kinase-4 in mouse skeletal muscle
Authors: Rinnankoski-Tuikka Rita , Silvennoinen Mika , Torvinen Sira , Hulmi Juha J , Lehti Maarit , Kivelä Riikka , Reunanen Hilkka , Kainulainen Heikki
Published: June 2012

Background

The expression of PDK4 is elevated by diabetes, fasting and other conditions associated with the switch from the utilization of glucose to fatty acids as an energy source. It is previously shown that peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α), a master regulator of energy metabolism, coactivates in cell lines pyruvate dehydrogenase kinase-4 (PDK4) gene expression via the estrogen-related receptor α (ERRα). We investigated the effects of long-term high-fat diet and physical activity on the expression of PDK4, PGC-1α and ERRα and the amount and function of mitochondria in skeletal muscle.

Methods

Insulin resistance was induced by a high-fat (HF) diet for 19 weeks in C57BL/6 J mice, which were either sedentary or with access to running wheels. The skeletal muscle expression levels of PDK4, PGC-1α and ERRα were measured and the quality and quantity of mitochondrial function was assessed.

Results

The HF mice were more insulin-resistant than the low-fat (LF) -fed mice. Upregulation of PDK4 and ERRα mRNA and protein levels were seen after the HF diet, and when combined with running even more profound effects on the mRNA expression levels were observed. Chronic HF feeding and voluntary running did not have significant effects on PGC-1α mRNA or protein levels. No remarkable difference was found in the amount or function of mitochondria.

Conclusions

Our results support the view that insulin resistance is not mediated by the decreased qualitative or quantitative properties of mitochondria. Instead, the role of PDK4 should be contemplated as a possible contributor to high-fat diet-induced insulin resistance.
Prenatal activation of Toll-like receptors-3 by administration of the viral mimetic poly(I:C) changes synaptic proteins, N-methyl-D-aspartate receptors and neurogenesis markers in offspring
Authors: Forrest Caroline M , Khalil Omari S , Pisar Mazura , Smith Robert A , Darlington Lynda Gail , Stone Trevor W
Published: June 2012

Background

There is mounting evidence for a neurodevelopmental basis for disorders such as autism and schizophrenia, in which prenatal or early postnatal events may influence brain development and predispose the young to develop these and related disorders. We have now investigated the effect of a prenatal immune challenge on brain development in the offspring. Pregnant rats were treated with the double-stranded RNA polyinosinic:polycytidylic acid (poly(I:C); 10 mg/kg) which mimics immune activation occurring after activation of Toll-like receptors-3 (TLR3) by viral infection. Injections were made in late gestation (embryonic days E14, E16 and E18), after which parturition proceeded naturally and the young were allowed to develop up to the time of weaning at postnatal day 21 (P21). The brains of these animals were then removed to assess the expression of 13 different neurodevelopmental molecules by immunoblotting.

Results

Measurement of cytokine levels in the maternal blood 5 hours after an injection of poly(I:C) showed significantly increased levels of monocyte chemoattractant protein-1 (MCP-1), confirming immune activation. In the P21 offspring, significant changes were detected in the expression of GluN1 subunits of NMDA receptors, with no difference in GluN2A or GluN2B subunits or the postsynaptic density protein PSD-95 and no change in the levels of the related small GTPases RhoA or RhoB, or the NMDA receptor modulator EphA4. Among presynaptic molecules, a significant increase in Vesicle Associated Membrane Protein-1 (VAMP-1; synaptobrevin) was seen, with no change in synaptophysin or synaptotagmin. Proliferating Cell Nuclear Antigen (PCNA), as well as the neurogenesis marker doublecortin were unchanged, although Sox-2 levels were increased, suggesting possible changes in the rate of new cell differentiation.

Conclusions

The results reveal the induction by prenatal poly(I:C) of selective molecular changes in the brains of P21 offspring, affecting primarily molecules associated with neuronal development and synaptic transmission. These changes may contribute to the behavioural abnormalities that have been reported in adult animals after exposure to poly(I:C) and which resemble symptoms seen in schizophrenia and related disorders.
Association Between Colonoscopy and Colorectal Cancer Mortality in a US Cohort According to Site of Cancer and Colonoscopist Specialty
Authors: Baxter Nancy N. , Warren Joan L. , Barrett Michael J. , Stukel Therese A. , Doria-Rose V. Paul
Published: June 2012

Purpose

We designed this study to evaluate the association of colonoscopy with colorectal cancer (CRC) death in the United States by site of CRC and endoscopist specialty.

Methods

We designed a case-control study using Surveillance, Epidemiology, and End Results (SEER)–Medicare data. We identified patients (cases) diagnosed with CRC age 70 to 89 years from January 1998 through December 2002 who died as a result of CRC by 2007. We selected three matched controls without cancer for each case. Controls were assigned a referent date (date of diagnosis of the case). Colonoscopy performed from January 1991 through 6 months before the diagnosis/referent date was our primary exposure. We compared exposure to colonoscopy in cases and controls by using conditional logistic regression controlling for covariates, stratified by site of CRC. We determined endoscopist specialty by linkage to the American Medical Association (AMA) Masterfile. We assessed whether the association between colonoscopy and CRC death varied with endoscopist specialty.

Results

We identified 9,458 cases (3,963 proximal [41.9%], 4,685 distal [49.5%], and 810 unknown site [8.6%]) and 27,641 controls. In all, 11.3% of cases and 23.7% of controls underwent colonoscopy more than 6 months before diagnosis. Compared with controls, cases were less likely to have undergone colonoscopy (odds ratio [OR], 0.40; 95% CI, 0.37 to 0.43); the association was stronger for distal (OR, 0.24; 95% CI, 0.21 to 0.27) than proximal (OR, 0.58; 95% CI, 0.53 to 0.64) CRC. The strength of the association varied with endoscopist specialty.

Conclusion

Colonoscopy is associated with a reduced risk of death from CRC, with the association considerably and consistently stronger for distal versus proximal CRC. The overall association was strongest if colonoscopy was performed by a gastroenterologist.
Tobacco Assessment in Actively Accruing National Cancer Institute Cooperative Group Program Clinical Trials
Authors: Peters Erica N. , Torres Essie , Toll Benjamin A. , Cummings K. Michael , Gritz Ellen R. , Hyland Andrew , Herbst Roy S. , Marshall James R. , Warren Graham W.
Published: June 2012

Purpose

Substantial evidence suggests that tobacco use has adverse effects on cancer treatment outcomes; however, routine assessment of tobacco use has not been fully incorporated into standard clinical oncology practice. The purpose of this study was to evaluate tobacco use assessment in patients enrolled onto actively accruing cancer clinical trials.

Methods

Protocols and forms for 155 actively accruing trials in the National Cancer Institute's (NCI's) Clinical Trials Cooperative Group Program were evaluated for tobacco use assessment at enrollment and follow-up by using a structured coding instrument.

Results

Of the 155 clinical trials reviewed, 45 (29%) assessed any form of tobacco use at enrollment, but only 34 (21.9%) assessed current cigarette use. Only seven trials (4.5%) assessed any form of tobacco use during follow-up. Secondhand smoke exposure was captured in 2.6% of trials at enrollment and 0.6% during follow-up. None of the trials assessed nicotine dependence or interest in quitting at any point during enrollment or treatment. Tobacco status assessment was higher in lung/head and neck trials as well as phase III trials, but there was no difference according to year of starting accrual or cooperative group.

Conclusion

Most actively accruing cooperative group clinical trials do not assess tobacco use, and there is no observable trend in improvement over the past 8 years. Failure to incorporate standardized tobacco assessments into NCI-funded Cooperative Group Clinical Trials will limit the ability to provide evidence-based cessation support and will limit the ability to accurately understand the precise effect of tobacco use on cancer treatment outcomes.
Elevated human epididymis protein 4 concentrations in chronic kidney disease
Authors: Nagy Béla , Krasznai Zoárd T , Balla Heidi , Csobán Mária , Antal-Szalmás Péter , Hernádi Zoltán , Kappelmayer János
Published: June 2012

Background

Human epididymis protein 4 (HE4) has recently become an available tumour biomarker for detecting ovarian cancer along with the standard cancer antigen 125 (CA125). However, it is unknown if the levels of HE4 and CA125 may be altered in subjects who have impaired renal function with no ovarian disorders.

Methods

In 113 female patients at different stages of chronic kidney disease (CKD) with no ovarian and lung cancer and 68 subjects with normal renal and ovarian function, HE4 and CA125 concentrations were analysed by using chemiluminescent microparticle immunoassay (Architect®, Abbott) and electrochemiluminescent immunoassay (Modular E170®, Roche), respectively. Renal function was evaluated by measuring serum creatinine and urea concentrations (Cobas Integra-800®, Roche). Estimated glomerular filtration rate (eGFR in mL/min/1.73 m2) was calculated by the 4v-MDRD formula.

Results

Significantly increased HE4 concentrations ( P < 0.0001) were found in individuals with differently decreased eGFR values (<90 mL/min/1.73 m2) compared with clinical controls. CA125 serum concentration was higher than normal in subjects with CKD3 (eGFR = 30–59 mL/min/1.73 m2), but significant elevation ( P = 0.006) in CA125 concentrations was seen only in those who had severe renal failure (CKD4-5; eGFR < 30 mL/min/1.73 m2). These tendencies were independent of age in our study cohort, and seemed to be more evident among women in premenopausal status.

Conclusions

HE4 concentrations may be elevated in CKD patients with no ovarian and lung cancer. Thus, HE4 results should be interpreted cautiously in women with renal disorders.
Reflex testing to define action limits for community-based requests
Authors: Barron Jeffrey , Ng Charles , Aspin Lisa , Robinson Lisa-Jane , Smith Geoff
Published: June 2012

Background

Critical values are required to be phoned 24/7. Other abnormal results fall short of the thresholds used to define critical values and may only be required to be phoned during the day. Community-based requestors prefer not to be contacted unless a result is critical and contacting them requires substantial staff resource. It is common practice to add tests to requests to expedite diagnosis or clarify the significance of a particular result using algorithms.

Methods

We devised algorithms for reflex addition of tests which allowed the differentiation of significantly abnormal results as either critical values or those that only require day phoning.

Results

Algorithms identified 158 out of 309 tests as being critical (51%) over nine months. Reflex addition of serum bicarbonate identified 4% of serum glucose (24.9–37.9 mmol/L) as critical. Use of estimated glomerular filtration rate by reflex addition of serum creatinine identified 68% of serum lithium (1.49–1.99 mmol/L) as critical. Addition of serum potassium, calcium and magnesium identified 21% of serum digoxin (>2.49 nmol/L) as critical and addition of serum potassium and calcium to all samples with serum magnesium (<0.31 mmol/L) identified hypocalcaemia in all cases. The addition of serum creatinine and potassium as markers for rhabdomyolysis-induced acute renal failure did not help in the differentiation of serum creatine kinase > 4999 μ/L.

Conclusions

Use of reflex tests helped inform a phoning system based on the division of results into critical values and non-emergency abnormal values. This avoids disturbing requestors unnecessarily and conserves staff time at night.
A two-dimensional approach to the study of podcasting in Spanish talk radio stations
Authors: Sellas Toni
Published: June 2012

Over the last decade, technology has transformed traditional radio broadcasting, not only as a mass medium but also as a cultural industry. Podcasting has been adopted by broadcasters as a useful tool for radio on demand. For broadcasters, it also offers the opportunity to explore new
formats and new radio content and the possibility of reaching listeners in new ways. This article discusses the use of podcasting by the main radio networks in Spain. It is based on a quantitative study amongst broadcasters, focused on those chains that have adopted podcasting to offer some
of their conventional broadcast programmes. The aim of the present study is to establish which elements of programming and business strategies are motivating the use of podcasts by these radio stations. In addition, this article also provides a first approach to the main genres and programmes
supplied in this format.
A Multicategory Model of Consumers' Purchase Incidence, Quantity, and Brand Choice Decisions: Methodological Issues and Implications on Promotional Decisions
Authors: Mehta Nitin , Ma Yu
Published: June 2012

The authors propose a multicategory model of consumers' purchase incidence, quantity, and brand choice decisions. The model specification allows for cross-category promotion effects in both components of the primary demand (incidence and quantity decisions) and uses a flexible functional form of consumer's utility to accurately measure those cross-category effects. To demonstrate the importance of the methodology, the authors investigate two issues of relevance to retailers, namely, how retailers should (1) allocate promotional expenditures across brands in a category and (2) coordinate timing of promotions of brands across categories. The authors estimate the proposed model using consumers' purchases in pasta sauce and pasta categories. The results reveal that using restrictive functional forms of utilities or ignoring cross-category effects in incidence and quantity decisions leads to incorrect assessments on relative allocation of promotional expenditures across brands. Furthermore, retailers are better off contemporaneously promoting brands across the two categories than promoting them in different periods, and ignoring cross-category effects in quantity decisions leads to the opposite inference, namely, that retailers are better off promoting brands across the two categories in different periods.
Rates of Nonsuicidal Self-Injury in Youth: Age, Sex, and Behavioral Methods in a Community Sample
Authors: Barrocas Andrea L. , Hankin Benjamin L. , Young Jami F. , Abela John R. Z.
Published: June 2012

OBJECTIVE:

The goal was to assess the rate and behavioral methods of nonsuicidal self-injury (NSSI) in a community sample of youth and examine effects of age and sex.

METHODS:

Youth in the third, sixth, and ninth grades (ages 7–16) at schools in the community were invited to participate in a laboratory study. A total of 665 youth (of 1108 contacted; 60% participation rate) were interviewed about NSSI over their lifetime via the Self-Injurious Thoughts and Behaviors Interview.

RESULTS:

Overall, 53 (8.0%) of the 665 youth reported engaging in NSSI; 9.0% of girls and 6.7% of boys reported NSSI engagement; 7.6% of third-graders, 4.0% of sixth-graders, and 12.7% of ninth-graders reported NSSI engagement. There was a significant grade by gender interaction; girls in the ninth grade (19%) reported significantly greater rates of NSSI than ninth-grade boys (5%). Behavioral methods of NSSI differed by gender. Girls reported cutting and carving skin most often, whereas boys reported hitting themselves most often. Finally, 1.5% of youth met some criteria for the proposed fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) diagnosis of NSSI.

CONCLUSIONS:

Children and adolescents engage in NSSI. Ninth-grade girls seem most at risk, as they engage in NSSI at 3 times the rate of boys. Behavioral methods of NSSI also vary by grade and gender. As possible inclusion of an NSSI diagnosis in the fifth edition of the DSM-5 draws near, it is essential to better understand NSSI engagement across development and gender.
Hallucinations After Withdrawal of Valproic Acid
Authors: de Laat Sanne A.A. , Hillegers Manon H.J. , Jansen Floor E. , Braun Kees P. , de Graeff-Meeder Elisabeth R.
Published: June 2012

We report 2 children with a history of epilepsy in whom valproic acid (VPA) withdrawal was identified as a potential cause of hallucinations. After a restart of VPA, the hallucinations disappeared. We suggest mechanisms for the occurrence of the hallucinations and a possible control of a predisposition to hallucinations by VPA.
Long-term Outcomes of Group B Streptococcal Meningitis
Authors: Libster Romina , Edwards Kathryn M. , Levent Fatma , Edwards Morven S. , Rench Marcia A. , Castagnini Luis A. , Cooper Timothy , Sparks Robert C. , Baker Carol J. , Shah Prachi E.
Published: June 2012

OBJECTIVE:

Group B Streptococcus (GBS) is the leading cause of meningitis in young infants. We evaluated long-term outcomes among GBS meningitis survivors. We hypothesized that despite reduced mortality, GBS meningitis would remain a significant cause of morbidity among GBS survivors.

METHODS:

Ninety term and near-term infants diagnosed with GBS meningitis from 1998 through 2006 were identified from 2 children’s hospitals. Five died acutely, and 5 died at 6 months to 3 years of age. Forty-three survivors (54%; mean age 6.8, range 3–12 years) were consented for evaluation and underwent physical and neurologic examinations, hearing and vision screening, and standardized developmental assessments. Associations among presenting features, laboratory parameters, neurologic status at hospital discharge, and later developmental outcomes were explored by using descriptive statistics and logistic regression.

RESULTS:

Twenty-four of 43 (56%) children evaluated demonstrated age-appropriate development, 11 (25%) had mild-to-moderate impairment, and 8 (19%) had severe impairment. Admission features associated with death after hospital discharge or severe impairment included lethargy (P = .003), respiratory distress (P = .022), coma or semicoma (P = .022), seizures (P = .015), bulging fontanel (P = .034), leukopenia (P = .026), acidosis (P = .024), cerebrospinal fluid protein >300 mg/dL (P = .006), cerebrospinal fluid glucose <20 mg/dL (P = .026), and need for ventilator (P = .002) or pressor support (P < .001). Features at discharge associated with late death or severe impairment included failed hearing screen (P = .004), abnormal neurologic examination (P < .001), and abnormal end of therapy brain imaging (P = .038).

CONCLUSIONS:

Survivors of GBS meningitis continue to have substantial long-term morbidity, highlighting the need for ongoing developmental follow-up and prevention strategies such as maternal immunization.
Buckling strength of axially compressed thin axisymmetric shells as affected by localized initial geometric imperfections
Authors: El Bahaoui J. , El Bakkali L. , Khamlichi A.
Published: June 2012

Buckling analysis of axially compressed cylindrical shells having one or two localized initial geometric imperfections was performed by using the finite element method. The imperfections of entering triangular form were assumed to be positioned symmetrically at the mid shell length. The buckling load was assessed in terms of shell aspect ratios, imperfection amplitude and wavelength, and the distance separating the imperfections. The obtained results have shown that amplitude and wavelength have major effects, particularly for short and thin shells. Two interacting imperfections were found to be more severe than a single imperfection, but the distance separating them has small influence.
The theoretical possibilities and significance of the competence development training and educational profile program with the support of the faculty of engineering, University of Debrecen
Authors: Rady E. A.
Published: June 2012

The rapidly changing organizational and business environment provides new challenges for higher education: both for teaching staff and students. The acquisition of professional skills alone is no longer enough for a successful career: Increasingly, there is a demand for continuous self-development.

This demand is represented at each end of the market: students who may wish to develop their personal skills and confidence, and companies which accordingly, may operate more efficiently with better prepared graduates. Introducing different alternatives for the acquisition of self-awareness and competencies into the higher education training palette can provide the basis for continuous self-development. The Life Long Learning objective is that students at all levels of education may acquire the self-awareness and competencies necessary for success in their chosen profession. The Faculty of Engineering group would support the implementation. The study's objectives are to identify the goals and present the results edited by the Competence Development Training Program research group formed at the University of Debrecen, Faculty of Engineering.
High-k dielectrics for hybrid floating gate memory applications
Authors: Lisoni J.G. , Breuil L. , Blomme P. , Van Houdt J.
Published: June 2012

We report on the materials issues involved in the hybrid floating gate (HFG) device fabrication, where the interpoly dielectric is replaced by an intermetal dielectric (IMD). Indeed, in HFG the dielectric is inserted in between two metal layers in a metal\dielectric\metal stack. The materials of choice were TiN as the metal layer and Al2O3 and HfO2 (and their combination) as IMD. The program/erase performance is discussed based on the dielectric constant and crystallinity of the IMD and the metal-IMD interface characteristics.
Development of organic resistive memory for flexible electronics
Authors: Frolet Nathalie , Charbonneau Micaël , Tiron Raluca , Buckley Julien , Mariolle Denis , Boutry Delphine , Coppard Romain , De Salvo Barbara
Published: June 2012

In this paper, we have performed further investigations and deepened our understanding of Polymer Resistive Random Access Memory devices (PoRRAM) on silicon substrate. Organic thin films based on blend of fullerene (C60) molecules and poly-methyl-methacrylate resist (PMMA) were analyzed from a material and electrical point of views. We have enlightened first the necessity of thermal treatment on the nano-composite layer in order to obtain memory effect in the device. Indeed from I-V measurements, only devices that had a thermal activation exhibited the hysteresis phenomenon, characteristic of the memory effect. The impact of thermal annealing has been investigated by morphological analysis (AFM and confocal microscopy) before and after thermal treatment. This process step induced the C60 molecules aggregation in the polymer matrix. The morphological study of these aggregates coupled with electrical measurements allowed us to determine the influence of aggregation on the electrical behavior. Due to their flexibility, this organic memories based on PMMA:C60 nanocomposites show a strong potential for an adaptation on plastic substrate.
Effect of degree of ceramsite prewetting on the cracking behaviour of LWAC
Authors: Ji Tao , Chen Caiyi , Zhuang Yizhou , Lin Xujian
Published: June 2012

The water absorption and desorption process, the interfacial transition zone (ITZ) and the cracking behaviour of lightweight aggregate concrete (LWAC) were obtained by a U-tube micro-pressure measurement device, a scanning electron microscopy test and a new restrained-shrinkage ring device, respectively. The study reveals that, with the increase in degree of ceramsite prewetting, the water absorption ability declines, while the water desorption ability improves for ceramsites embedded in the LWAC, and the ITZ of the LWAC becomes compact. The cracking ages of the LWAC rings with ceramsites prewetted for 0 h, 1 h and 24 h are respectively 10·7 days, 15·3 days and 25 days. At the age of 28 days, the crack width of LWAC rings decreases with the increase in degree of ceramsite prewetting. Also, with the increase in degree of ceramsite prewetting, the restrained-shrinkage cracking behaviour of the LWAC rings improves. The research results provide clues for the preparation of the LWAC with better crack-resistant behaviour.
Phosphors for full‐color low‐voltage field‐emission displays
Authors: Jacobsen Stuart M.
Published: June 2012

Abstract— The development of phosphors to enable full‐color low‐voltage field‐emission displays (FEDs) is discussed. The importance of understanding the broad range of other FED enabling technologies (architectures, spacers, duty factor, vacuum technology, etc.) in order to define the key role that phosphors can play in realizing these displays is stressed. Beginning with the demands of spacer technology that primarily limits FED working voltage, a broad overview is then given on phosphor issues including an introduction to phosphor saturation mechanisms at low voltage and the applicability of certain donor‐acceptor, rare‐earth, and transition‐metal ion phosphors to meet the requirements. The paper concludes by demonstrating that phosphor development, especially in the range of excitation of 500–1000 V, will have a significant impact on the future of FEDs.
A trophic cascade triggers collapse of a salt‐marsh ecosystem with intensive recreational fishing
Authors: Altieri Andrew H. , Bertness Mark D. , Coverdale Tyler C. , Herrmann Nicholas C. , Angelini Christine
Published: June 2012

Overexploitation of predators has been linked to the collapse of a growing number of shallow‐water marine ecosystems. However, salt‐marsh ecosystems are often viewed and managed as systems controlled by physical processes, despite recent evidence for herbivore‐driven die‐off of marsh vegetation. Here we use field observations, experiments, and historical records at 14 sites to examine whether the recently reported die‐off of northwestern Atlantic salt marshes is associated with the cascading effects of predator dynamics and intensive recreational fishing activity. We found that the localized depletion of top predators at sites accessible to recreational anglers has triggered the proliferation of herbivorous crabs, which in turn results in runaway consumption of marsh vegetation. This suggests that overfishing may be a general mechanism underlying the consumer‐driven die‐off of salt marshes spreading throughout the western Atlantic. Our findings support the emerging realization that consumers play a dominant role in regulating marine plant communities and can lead to ecosystem collapse when their impacts are amplified by human activities, including recreational fishing.
Study of Steam Injection in a Fractured Carbonate Heavy Oil Reservoir in Iran
Authors: Mohammadi Sh. , Ehsani M. R. , Nikookar M. , Sahranavard L. , Garakani A. Soleimani
Published: June 2012

In this paper, three dimensional modeling of steam injection in a fractured carbonate reservoir containing heavy-oil was performed. The paper describes a numerical Technique that simulates three-dimensional heat transfer and three-dimensional, three-phase fluid flow in a reservoir.This model considered both capillary and gravity effects in the energy equation and a variable porosity. First, steam injection process was modeled in a non-fractured reservoir, then, the model accuracy was assessed. The results showed that steam injection in a non-fractured reservoir increases the oil recovery to 70 %. In the next step, steam injection process was modeled in a fractured reservoir. The amount of oil recovery in this reservoir was estimated about 30 %.The sensitivity analysis for identification and evaluation of steam injection process in both non-fractured and fractured reservoirs was performed. The results indicated that some parameters such as: injection pressure, steam quality, pre-heating, permeability and location of fracture effect on the oil recovery. Oil recovery from carbonate fractured reservoirs is less compared with non-fractured reservoirs, and breakthrough occurs sooner.
Applicability of Slug Flow Models to Heavy Oils
Authors: Lacy Claud E.
Published: June 2012

New slug flow data and closure relationships for heavy oils have recently become available in the literature for both horizontal and vertical flow. This laboratory data allows the testing of current modeling technology to understand what modeling gaps must be addressed and where more data is needed. Comparisons of the data with typical one-dimensional slug flow models were performed at conditions where the liquid flow in the liquid slug is either laminar, transition or weakly turbulent flow. The closure relationships such as distribution parameter, drift velocity, and holdup in liquid slug are discussed along with the impact of these choices.
Numerical Simulation for the Profile Control Combination Process of Steam Foam and Stiff Particles
Authors: Feng Qihong , Wang Sen , Liu Ping , Ge Pingyuan , Shi Shubin , Sun Yiling
Published: June 2012

Profile control by steam foam is commonly used as an effective EOR method for the development of heavy oil reservoirs. However, due to the limited shut-off capacity of foams, the existence of thief zones or high-conductive layers will result in short validity period and poor efficiency. Therefore, steam foam profile control process assisted by stiff particles (SFPCASP) is presented, i.e. stiff particles are firstly injected into the reservoir to plug high-permeability zones, and then steam foam is injected.

The objective here is to establish a numerical method to simulate the combination process. A three-dimensional, three-phase, five-component mathematical model is put forward, which takes into account the principal physico-chemical phenomena and the synergic action. Based on the model, a corresponding numerical simulator is developed, in which FIM (Fully Implicit Method) is applied to ensure the stability and to simulate the reservoir accurately.

An oilfield pilot test has been carried out, and the development scheme is optimized. Compared with only steam foam injection, the best project of the combination process would increase 6.3% of the heavy oil recovery, which effectively demonstrate the validity of the technology. Moreover, the performance of the pilot test was in agreement with the prediction.

In addition, this work provides a platform which can be applied to simulate profile control process by steam foam, by stiff particles or by both of them.
Application of Nanofluid Technology to Improve Recovery in Oil and Gas Wells
Authors: McElfresh Paul , Holcomb David , Ector Daniel
Published: June 2012

The use of aqueous stabilized nanoparticle dispersions (NPDs) with 4-20 nm silicon dioxide particles has been demonstrated in both experimental laboratory evaluations and field trials to provide production improvements in wellbore remediation and increased injectivity over conventional treatments. To date over 50 successful beta test applications have been performed. Additional work is under way to develop improved NPD formulations that will enable applications in areas like hydraulic fracturing, acidizing, production chemicals, water flooding, tar sands, and heavy oil.

Nanofluids are stable colloidal dispersions or micellar dispersions that accelerate recovery of hydrocarbon from oil and gas reservoirs by the use of the unique enabling mechanism of disjoining pressure. The nanoparticles in NPD utilize this mechanism to form a self-assembled wedge-shaped film on contact with a discontinuous phase. This wedge film acts to separate formation fluids (oil, paraffin, water, and/or gas) from the formation's surface, thereby recovering more fluids than previously possible with conventional additives or fluids.

This paper will present a description of the disjoining pressure mechanism and present Research laboratory and actual field treatment beta testing to illustrate that higher fluid recoveries and injection rates can be achieved, by enabling conventional intervention fluids to function more efficiently.
Environmentally Acceptable Compositions Comprising Nanomaterials for Plugging and Sealing Subterranean Formations
Authors: Patil Prajakta , Kalgaonkar Rajendra
Published: June 2012

High water production greatly affects the economic life of producing wells and is a serious problem in the oil industry. Excessive water cut is also responsible for many oilfield-related damage mechanisms, such as scale deposition, fines migration, corrosion, etc. Nanomaterials, such as nanosilica, in combination with chelating agents, could be used for plugging and sealing water-or gas-producing zones (bottom-water coning, gas coning, natural fractures, etc.), thus improving oil recovery.

The nanosilica used in design of water shutoff is an inorganic material with properties of no dissolution or aggregation in a liquid environment. Moreover, the entire system, including the chelating agent, is compatible with reservoir fluids and is environmentally acceptable. The particle size of nanosilica greatly influences the structural properties of the material. These aspects, in turn, exhibit a strong effect on chemical reactivity. The smaller particle size of nanosilica than previously used silica products generates increased surface area and interface atoms, which in turn increases the surface free energy and associated structural perturbations.

This paper presents the development of a novel, environmentally acceptable conformance sealant that incorporates nanosilica and an activator. Different chelating agents, which are also non-toxic and biodegradable, are used as activators in this conformance evaluation. The newly developed system can effectively prevent water and gas flow in BHSTs up to 300°F. The static gelation times were evaluated at different temperatures up to 300°F. An increase in temperature caused an increase in the particle collision, which led to lower gelation times. The effects of pH and concentration of activators on gelation times of the new conformance system were also studied. The gelation time could be controlled by adjusting the concentration of the activator, which is advantageous because it allows the sealant to remain pumpable over predictable periods of time.
Game Changing Technology with MWNT Nanocomposites for HTHP and Hostile Environment Sealing in Enhancing Oil Recovery
Authors: Ito Masaei , Madhavan Raghu , Osawa Osamu , Noguchi Toru , Ueki Hiroyuki , Takeuchi Kenji , Endo Morinobu
Published: June 2012

A key challenge in exploiting the untapped hydrocarbons in hotter and deeper reservoirs is the lack of reliable HTHP (high temperature and high pressure) technology. This paper introduces a novel sealing material based on MWNT (Multi-wallel Carbon Nanotubes) and Rubber Nanocomposites for use in the exploration and development of HTHP reservoirs.

Prior efforts in developing the Nanocomposites technology have identified two key challenges, namely, the uniform dispersion of MWNT and the poor bonding between MWNT and the rubber matrix. By developing innovative and new processes, we have resolved the issues of dispersion and bonding in 2008. The new process technologies we are pioneering are enabling us to develop a series of novel sealing systems for the HTHP environments. In one of the new sealing systems, we were able to a significantly increase the sealing performance of an existing system from 40 °C to 175 °C and 20,000 psi to one that can seal ‒10 °C to 260 °C and 45,000 psi, temperature and pressure ranges.

We have completed an extensive series of tests to check the durability and reliability of the new sealing systems, including chemical-resistance tests in mud, hydrocarbon oil, brines, H2S, CO2 and in HTHP conditions. We had several successful field trials of the new sealing system around the globe, including, the Gulf of Mexico, North Sea, Arabian Peninsula, Africa, Asia and US land. Having established the technology and its benefits in extending reliable field operations, we are now championing its use in the exploration and development efforts in hostile frontiers. We believe that our new sealing solutions based on Nanotechnology and processes are proving to meet the critical needs in the exploration and development of HT and/or HP, deep water, and other hostile environment reservoirs
Carbon Nanotube-Based High Temperature Vacuum Microelectronics for E&P Applications
Authors: Manohara H.. , Mojarradi M.. , Toda R.. , Lin R. H.
Published: June 2012

Field emission from carbon nanotube (CNT) bundles has been applied to develop new class of computational vacuum microelectronics for harsh environment applications. CNTs have demonstrated superior field emission performance because of their low emission threshold, high current density, and are conducive for monolithic integration with silicon structures to develop microelectronic/microsensor systems. In this paper we present high-temperature tolerant "digital" vacuum electronics using CNTs. This technology is applicable to in situ sensor electronics for down-hole applications where the operating environment is high temperature, high pressure, and has corrosive chemicals. The digital and analog electronic devices developed using CNT-vacuum microelectronic technology can be integrated with sensor systems to achieve prolonged stand-alone operation during E&P. NASA-JPL has developed high performance cold cathodes using arrays of carbon nanotube bundles that produce > 15 A/cm2 at applied fields of 6 to 8 V/μm. They have exhibited robust operation in poor vacuums of 10‒7 to 10‒4 Torr-a typically achievable range inside hermetically sealed microcavities. By monolithically integrating CNT cathodes with micromachined Si multi-gate structures we have demonstrated a new class of programmable "vacuum" logic gates. We have achieved switching operation at temperatures up to 700° C. The initial design, operation, and the potential performance in an improved design will be presented in this paper along with vacuum packaging techniques to make stand alone devices for circuit board integration. CNT-vacuum microelectronics opens up a new regime of in situ electronics for novel sensor/electronics systems because of their inherent high-temperature tolerance, and corrosion resistance. Unlike traditional vacuum tubes, these are low power, miniature, and potentially as fast as their solid-state counterparts while exhibiting superior reverse bias or leakage current characteristics. These devices offer potential to significantly enhance E&P operation.
An Analysis of the Caprock Failure at Joslyn
Authors: Carlson M. R.
Published: June 2012

A significant caprock failure occurred on the Joslyn SAGD property in 2006, which has had a wide impact on the approval process for future SAGD projects. Two reports were released by the Alberta Government: "Total E&P Canada Ltd., Surface Steam Release of May 18, 2006, Joslyn Creek SAGD Thermal Operation, ERCB Staff Review and Analysis, February 11th, 2010" and "Summary of Investigations into the Joslyn May 18th, 2006 Steam Release, Total E&P Canada Ltd.". The latter report is very large. A number of potential mechanisms are postulated without definitive resolution. The most likely failure suggested involved transmission of fluids up a 50,000 mD chimney and a pancake shaped lens of high pressure steam that resulted in a shear failure of the caprock.

The author believes that this scenario is unlikely from a geological and heat transfer perspective. There are other anomalies. Peak stresses in most caprock coupled reservoir-geomechanical simulations normally peak between 3 to 7 years after start-up. However, the Joslyn failure occurred immediately after conversion from partial SAGD to full SAGD, in which the producing well was killed and a PCP pump was run.

There are other issues that should be considered that include: How hydraulic fractures are initiated and propagated. The literature shows us: computer design programs that predict fracture propagation and shape,analytical solutions that also show expected fracture morphology; and,physical examples which have been dug up or coredIn addition the geological record provides excellent analogue information on the morphology of high pressure intrusions. These various types of data will be compared to the observed morphology derived from the 3D seismic.

Earlier work by Edmunds and Good has shown that extremely transient conditions exist in SAGD wells that result in "geysering" or slugging within the producing well. The energy available from water and steam is enormous. The nuclear and power industry previously made these similar discoveries after a series of catastrophic failures of piping systems. Analytical and computer simulation tools from the nuclear industry will be used to show that extremely high pressure transients, many times over fracture initiation pressures, can be expected. This is the same mechanism that resulted in the catastrophic failure of MEG Energy’s Christina Lake main steam distribution line.

In summary, there is every reason to believe that when hot steam was injected into a cooled (water) condensate filled well; very large pressure transients can be expected from phase changes within the piping that should result in a frac to surface.