bluuebunny/crossref_metadata_2025 huggingface dataset:
Detection of bacterial DNA by PCR in dogs with stifle pathology
Authors: Bhandal Jitender , Hayashi Kei , Kim Sun‐Young , Klein Martha , Wong Alice , Toupadakis Chrisoula A. , Muir Peter , Yellowley Clare E.
Published: September 2013

Objective

To determine presence of bacterial DNA in canine stifles with cranial cruciate ligament rupture (CCLR) and medial patellar luxation (MPL) compared to normal canine stifles (control).

Study design

Prospective clinical study.

Animals

Dogs (n = 44).

Methods

Dogs of varying age, breed, sex, and weight residing in California were assessed for stifle pathology (CCLR, MPL, or normal control). Synovial fluid of all stifles was assessed for the presence of bacterial DNA using broad‐ranging 16S rRNA primers and PCR.

Results

Bacterial DNA was detected in normal control stifles and those with CCLR and MPL. There were no statistical differences in the copy numbers of bacterial DNA in the stifle synovial fluid among groups (P > .05); however, synovial fluid specimens from dogs with stifle pathology (CCLR and MPL combined) tended to have higher copy numbers of bacterial DNA than those from controls (P = .06). There was no significant difference in the number of bacterial DNA between the CCLR and MPL groups (P = .57). The copy numbers of bacterial DNA had a weak positive significant correlation with the duration of lameness in CCLR group (P < .05).

Conclusions

Increased detection of bacterial DNA in the stifle synovial fluid may indicate joint pathology but not be directly linked to a specific joint disease.
Building a global community of policymakers, researchers and educators to move education systems into the digital age
Authors: Voogt J. , Knezek G.
Published: September 2013

The EDUsummIT 2011 aimed to develop (a) recommendations for policy, practice and research that will help educational systems move into the digital age and (b) strategies to build a global community of researchers, policymakers and teachers in the field of Information and Communication Technology (ICT) in Education. Thematic working groups addressed these goals from different perspectives: the learner, the teacher, curriculum and assessment, the structure of schooling, essential conditions for ICT integration and researching IT in education. This special issue reflects the research evidence underpinning the discussions and recommendations of the EDUsummIT thematic working groups.
Challenges to learning and schooling in the digital networked world of the 21st century
Authors: Voogt J. , Erstad O. , Dede C. , Mishra P.
Published: September 2013

This article elaborates on the competencies, often referred to as 21st century competencies, that are needed to be able to live in and contribute to our current (and future) society. We begin by describing, analysing and reflecting on international frameworks describing 21st century competencies, giving special attention to digital literacy as one of the core competencies for the 21st century. This is followed by an analysis of the learning approaches that are considered appropriate for acquiring 21st century competencies, and the specific role of technology in these learning processes. Despite some consensus about what 21st century competencies are and how they can be acquired, results from international studies indicate that teaching strategies for 21st century competencies are often not well implemented in actual educational practice. The reasons for this include a lack of integration of 21st century competencies in curriculum and assessment, insufficient preparation of teachers and the absence of any systematic attention for strategies to adopt at scale innovative teaching and learning practices. The article concludes with a range of specific recommendations for the implementation of 21st century competencies.
An Organized Approach to the Localization, Mapping, and Ablation of Outflow Tract Ventricular Arrhythmias
Authors: HUTCHINSON MATHEW D. , GARCIA FERMIN C.
Published: September 2013

Localization, Mapping, and Ablation of Outflow Tract Ventricular Arrhythmias

The outflow tract (OT) regions of the right and left ventricles, common sites of origin for idiopathic ventricular arrhythmias (VA), have complex three‐dimensional anatomical relationships. The understanding of in situ or “attitudinal” relationships not only informs the electrocardiographic interpretation of VA site of origin, but also facilitates their catheter‐based mapping and ablation strategies. By viewing each patient as his or her own “control,” the expected changes in ECG morphology (i.e., frontal plane QRS axis and precordial transition) between adjacent intracardiac structures (e.g., RVOT and aortic root) can be reliably predicted. Successful mapping of OT VAs involve a combination of activation and pacemapping guided by fluoroscopy, electroanatomical mapping, and intracardiac echocardiography. The purpose of this manuscript is to provide a simple, reliable strategy for catheter based mapping and ablation of OT VAs. We also discuss 2 specific challenges in OT VA mapping: (1) differentiating posterior RVOT from right coronary cusp VA origin; and (2) mapping VAs originating from the LV summit.
Berberine potently attenuates intestinal polyps growth in ApcMin mice and familial adenomatous polyposis patients through inhibition of Wnt signalling
Authors: Zhang Junfang , Cao Hailong , Zhang Bing , Cao Hanwei , Xu Xiuqin , Ruan Hang , Yi Tingting , Tan Li , Qu Rui , Song Gang , Wang Bangmao , Hu Tianhui
Published: September 2013

As a traditional anti‐inflammatory Chinese herbal medicine, Alkaloid berberine has been recently reported to exhibit anti‐tumour effects against a wide spectrum of cancer. However, the mechanism was largely unknown. Gene chip array reveals that with berberine treatment, c‐Myc, the target gene of Wnt pathway, was down‐regulated 5.3‐folds, indicating that berberine might inhibit Wnt signalling. TOPflash analysis revealed that Wnt activity was significantly reduced after berberine treatment, and the mechanism of which might be that berberine disrupted β‐catenin transfer to nucleus through up‐regulating the expression of adenomatous polyposis coli (APC) gene and stabilized APC‐β‐catenin complex. Berberine administration in ApcMin/+ mice exhibited fewer and smaller polyps in intestine, along with reduction in cyclin D1 and c‐Myc expression. In clinical practice, oral administration of berberine also significantly reduced the familial adenomatous polyposis patients' polyp size along with the inhibition of cyclin D1 expression in polyp samples. These observations indicate that berberine inhibits colon tumour formation through inhibition of Wnt/β‐catenin signalling and berberine might be a promising drug for the prevention of colon cancer.
Shareholder Activism and Earnings Management Incentives: An Empirical Examination of Shareholder Proposals in the United States
Authors: Sun Yan , Wang Weimin , Wang Xu (Frank) , Zhang William
Published: September 2013

In this article, we investigate the effect of shareholder activism on earnings management. Using a US sample of shareholder pay‐for‐performance proposals sponsored by institutional investors, we find that when compared to control firms, firms targeted by shareholder proposals have a greater magnitude of discretionary accruals (DA) in their reported earnings. In addition, we find that the likelihood of meeting or beating earnings benchmarks through the use of DA is higher for targeted firms whose managers have job security concerns due to the firms’ inferior stock performance in the past or have plans to sell company stock. Our results are consistent with the notion that pay‐for‐performance proposals have unintended consequences by introducing or exacerbating incentives to manage earnings for short‐term gains. The results also indicate that, for financial reporting, the short‐termism effect may dominate the alignment and/or disciplinary effect of shareholder monitoring.
Do Islamic Banks Employ Less Earnings Management?
Authors: Quttainah Majdi A. , Song Liang , Wu Qiang
Published: September 2013

In this article, we examine whether Islamic banks are less likely to manage their earnings than non‐Islamic banks and how Islamic banks’ unique corporate governance system, especially Shari'ah Supervisory Boards, impacts earnings management behaviors within Islamic banks. Using a sample of Islamic banks and their matched non‐Islamic banks in 15 countries, we find that, first, Islamic banks are less likely to conduct earnings management as measured by both earnings loss avoidance and abnormal loan loss provisions. Second, there are no significantly different earnings management behaviors between Islamic banks with and without Shari'ah Supervisory Boards. Third, several Shari'ah Supervisory Board characteristics, such as size and the presence of members from Auditing Organization for Islamic Financial Institutions, are important determinants of the earnings management of Islamic banks who have Shari'ah Supervisory Boards.
Costamere remodeling with muscle loading and unloading in healthy young men
Authors: Li Ruowei , Narici Marco V. , Erskine Robert M. , Seynnes Olivier R. , Rittweger Jörn , Pišot Rado , Šimunič Boštjan , Flück Martin
Published: September 2013

Costameres are mechano‐sensory sites of focal adhesion in the sarcolemma that provide a structural anchor for myofibrils. Their turnover is regulated by integrin‐associated focal adhesion kinase (FAK). We hypothesized that changes in content of costamere components (beta 1 integrin, FAK, meta‐vinculin, gamma‐vinculin) with increased and reduced loading of human anti‐gravity muscle would: (i) relate to changes in muscle size and molecular parameters of muscle size regulation [p70S6K, myosin heavy chain (MHC)1 and MHCIIA]; (ii) correspond to adjustments in activity and expression of FAK, and its negative regulator, FRNK; and (iii) reflect the temporal response to reduced and increased loading. Unloading induced a progressive decline in thickness of human vastus lateralis muscle after 8 and 34 days of bedrest (−4% and −14%, respectively; n = 9), contrasting the increase in muscle thickness after 10 and 27 days of resistance training (+5% and +13%; n = 6). Changes in muscle thickness were correlated with changes in cross‐sectional area of type I muscle fibers (r = 0.66) and beta 1 integrin content (r = 0.76) at the mid‐point of altered loading. Changes in meta‐vinculin and FAK‐pY397 content were correlated (r = 0.85) and differed, together with the changes of beta 1 integrin, MHCI, MHCII and p70S6K, between the mid‐ and end‐point of resistance training. By contrast, costamere protein level changes did not differ between time points of bedrest. The findings emphasize the role of FAK‐regulated costamere turnover in the load‐dependent addition and removal of myofibrils, and argue for two phases of muscle remodeling with resistance training, which do not manifest at the macroscopic level.
Commitment and Extremism: A Goal Systemic Analysis
Authors: Klein Kristen M. , Kruglanski Arie W.
Published: September 2013

Growing evidence suggests that uncertainty is related to extremism in its various forms. The aim of the present article is to probe the underlying psychological mechanisms of this relation. We begin by considering two disparate definitions of extremism as: (1) expressed zeal/attitude polarity, and (2) deviation from a norm. Zeal constitutes a direct expression of goal commitment, whereas deviant behavior is likely to occur under high commitment because of the greater perceived instrumentality of such behavior to the goal. We discuss a psychological mechanism that implies this increased instrumentality of deviant behavior to its goal. From this perspective, the relation between uncertainty and extremism represents a special case of the general relation between goal commitment and extremism: An aversively high degree of uncertainty augments commitment to the goal of uncertainty reduction. This in turn increases the appeal of extreme expressions seen as effective ways and means to uncertainty reduction.
Diabetes Severity, Metabolic Syndrome, and the Risk of Erectile Dysfunction
Authors: Weinberg Aviva E. , Eisenberg Michael , Patel Chirag J. , Chertow Glenn M. , Leppert John T.
Published: September 2013

Introduction

Erectile dysfunction (ED) is more common in men with type 2 diabetes mellitus (T2DM), obesity, and/or the metabolic syndrome (MetS).

Aim

The aim of this study is to investigate the associations among proxy measures of diabetic severity and the presence of MetS with ED in a nationally representative U.S. data sample.

Methods

We performed a cross-sectional analysis of adult participants in the 2001–2004 National Health and Nutrition Examination Survey.

Main Outcome Measures

ED was ascertained by self-report. T2DM severity was defined by calculated measures of glycemic control and insulin resistance (IR). IR was estimated using fasting plasma insulin (FPI) levels and the homeostasis model assessment of IR (HOMA-IR) definition. We classified glycemic control using hemoglobin-A1c (HbA1c) and fasting plasma glucose (FPG) levels. MetS was defined by the American Heart Association and National Heart, Lung, and Blood Institute criteria. Logistic regression models, adjusted for sociodemographics, risk factors, and comorbidities, were fitted for each measure of T2DM severity, MetS, and the presence of ED.

Results

Proxy measures of glycemic control and IR were associated with ED. Participants with FPG between 100–126mg/dL (5.6–7mmol/L) and ≥126mg/dL (>7mmol/L) had higher odds of ED, odds ratio (OR) 1.22 (confidence interval or CI, 0.83–1.80), and OR 2.68 (CI, 1.48–4.86), respectively. Participants with HbA1c 5.7–6.4% (38.8–46.4mmol/mol) and ≥6.5% (47.5mmol/mol) had higher odds of ED (OR 1.73 [CI, 1.08–2.76] and 3.70 [CI, 2.19–6.27], respectively). When FPI and HOMA-IR were evaluated by tertiles, there was a graded relation among participants in the top tertile. In multivariable models, a strong association remained between HbA1c and ED (OR 3.19 [CI,1.13–9.01]). MetS was associated with >2.5-fold increased odds of self reported ED (OR 2.55 [CI, 1.85–3.52]).

Conclusions

Poor glycemic control, impaired insulin sensitivity, and the MetS are associated with a heightened risk of ED.
Gellner redux?
Authors: Meadwell Hudson
Published: September 2013

The work of Ernest Gellner continues to be an influential part of nationalism studies. A recent appraisal has raised questions about the argument that Gellner offered in his central text on nationalism, Nations and Nationalism. This article takes up other issues in Gellner's work on nationalism. The article examines Gellner's influential definition of nationalism and the interpretation that he placed on that definition, as well as his treatment of ‘political cohabitation’. It also pays more attention to Gellner's later work, namely, Gellner's discussion of ‘the time zones of nationalism’. The paper draws on secondary literature but its primary purpose is to assess the coherence of Gellner's arguments.
Progress on obesity prevention over 20 years in Australia and New Zealand
Authors: Swinburn B. , Wood A.
Published: September 2013

The lessons learned from over 20 years of obesity prevention efforts in Australia and New Zealand are presented. The obesity epidemic started in the 1980s but poor monitoring systems meant the rise in obesity prevalence initially went undetected. In the 1990s, experts started advocating for government action; however, it was the rapid increase in media reports on obesity in the early 2000s which created the pressure for action. Several, comprehensive reports produced some programme investment but no regulatory policies were implemented. The powerful food industry lobby ensured this lack of policies on front‐of‐pack food labelling, restrictions on unhealthy food marketing to children, or taxes on unhealthy foods. The New Zealand government even backpedalled by rescinding healthy school food guidelines and withdrawing funding for the comprehensive national obesity strategy. In 2007, Australian Governments started a major long term‐investment in preventive health in order to improve economic productivity. Other positive initiatives, especially in Australia, were: the establishment of several advocacy organizations; successful, long‐term, whole‐of‐community projects reducing childhood obesity; a national knowledge exchange system for practitioners; and some innovative programmes and social marketing. However, despite multiple reports and strong advocacy, key recommended regulatory policies remain unimplemented, largely due to the private sector interests dominating public policy development.
Overview: Bellagio Conference on Program and Policy Options for Preventing Obesity in the Low‐ and Middle‐Income Countries
Authors: Popkin B. , Monteiro C. , Swinburn B.
Published: September 2013

The Bellagio ‘Conference on Program and Policy Options for Preventing Obesity in the Low‐ and Middle‐Income Countries’ (LMICs) was organized to pull together the current. We need not reiterate the importance of this topic or the speed of change in eating, drinking and moving facing us across the globe. The conference emerges from need to significantly step up the policies and programs to reduce obesity by learning from some current examples of best practice and strengthening the role of the academic and civil society players in translating global evidence and experience into action at the national level. There is also a need to empower the younger generation of scholars and activists in these countries to carry on this effort. The meeting was also timely because a number of funding agencies in the United States, Canada and the UK, at least, are beginning to focus attention on this topic. This set of papers provides not only examples of existing best practice but also a road map ahead for LMICs in the various areas of action needed to reduce obesity across LMICs. The meeting highlighted critical barriers to implementation that have blocked many initiatives.
Electrophysiology of blunted emotional bias in psychopathic personality
Authors: Carolan Patrick L. , Jaspers‐Fayer Fern , Asmaro Deyar T. , Douglas Kevin S. , Liotti Mario
Published: September 2013

Diminished emotional capacity is a core characteristic of psychopathic personality. We examined behavioral and electrophysiological differences in attentional bias to emotional material in 34 healthy individuals rated high or low in psychopathic traits using the short form of the Psychopathic Personality Inventory–Revised (18 high‐trait, 16 low‐trait). While performing an emotional Stroop task, high‐trait participants displayed reduced emotional modulation of the late positive potential (LPP, 400–600 ms), and early anterior positivity (EAP, 200–300 ms) amplitudes. Results suggest blunted bias to affective content in psychopathic personality, characterized by diminished early capture to emotional salience (EAP) and dampened cognitive emotional processing (LPP).
Timing of Dialysis Initiation in Acute Kidney Injury and Acute‐On‐Chronic Renal Failure
Authors: Macedo Etienne , Mehta Ravindra L
Published: September 2013

The decision to provide dialytic support and choosing the ideal moment to initiate therapy are common impasses for physicians treating patients with acute kidney injury (AKI). Although renal replacement therapy (RRT) has been extensively used in clinical practice for more than 30 years, there is a paucity of evidence to guide clinicians on the optimal utilization of RRT in AKI. In the absence of traditional or urgent indications, there is no consensus on whether dialysis should be offered and when it should be started. The lack of agreed‐upon parameters to guide the decision, the fear of the risk of the procedure, and the possible contribution to worse prognosis with RRT have resulted in a considerable variation in practice among physicians and centers. In this review, we summarize the evidence evaluating time of initiation of RRT and discuss possible approaches for future trials in addressing this issue.
Timing of Return to Dialysis in Patients with Failing Kidney Transplants
Authors: Molnar Miklos Z. , Ichii Hirohito , Lineen James , Foster Clarence E. , Mathe Zoltan , Schiff Jeffrey , Kim S. Joseph , Pahl Madeleine V. , Amin Alpesh N. , Kalantar‐Zadeh Kamyar , Kovesdy Csaba P.
Published: September 2013

In the last decade, the number of patients starting dialysis after a failed kidney transplant has increased substantially. These patients appear to be different from their transplant‐naïve counterparts, and so may be the timing of dialysis therapy initiation. An increasing number of studies suggest that in transplant‐naïve patients, later dialysis initiation is associated with better outcomes. Very few data are available on timing of dialysis reinitiation in failed transplant recipients, and they suggest that an earlier return to dialysis therapy tended to be associated with worse survival, especially among healthier and younger patients and women. Failed transplant patients may also have unique issues such as continuation of immunosuppression versus withdrawal or the need for remnant allograft nephrectomy with regard to dialysis reinitiation. These patients may have a different predialysis preparation work‐up, worse blood pressure control, higher or lower serum phosphorus levels, lower serum bicarbonate concentration, and worse anemia management. The choice of dialysis modality may also represent an important question for these patients, even though there appears to be no difference in mortality between patients starting peritoneal versus hemodialysis. Finally, failed transplant patients returning to dialysis appear to have a higher mortality rate compared with transplant‐naïve incident dialysis patients, especially in the first several months of dialysis therapy. In this review, we will summarize the available data related to the timing of dialysis initiation and outcomes in failed kidney transplant patients after returning to dialysis.
A Spatio‐Temporal Graph Model for Marine Dune Dynamics Analysis and Representation
Authors: Thibaud Rémy , Del Mondo Géraldine , Garlan Thierry , Mascret Ariane , Carpentier Christophe
Published: September 2013

Defining a model for the representation and the analysis of spatio‐temporal dynamics remains an open domain in geographical information sciences. In this article we investigate a spatio‐temporal graph‐based model dedicated to managing and extracting sets of geographical entities related in space and time. The approach is based on spatial and temporal local relations between neighboring entities during consecutive times. The model allows us to extract sets of connected entities distant in time and space over long periods and large spaces. FromGISconcepts and qualitative reasoning on space and time, we combine the graph model with a dedicated spatial database. It includes information on geometry and geomorphometric parameters, and on spatial and temporal relations. This allows us to extend classical measurements of spatial parameters, with comparisons of entities linked by complex relations in space and time. As a case study, we show how the model suggests an efficient representation of dunes dynamics on a nautical chart for safe navigation.
Epidemiology and risk factors for infections in myelodysplastic syndromes
Authors: Sullivan L.R. , Sekeres M.A. , Shrestha N.K. , Maciejewski J.P. , Tiu R.V. , Butler R. , Mossad S.B.
Published: September 2013

We conducted a case–control study to describe the epidemiology and risk factors for infections requiring hospitalization in patients with myelodysplastic syndromes (MDS). Of 497 patients identified, 103 patients developed 201 episodes of infection. The probability of acquiring an infection 1 year from date of MDS diagnosis was 15% (95% confidence interval [CI] 12–18%). Patients developing infections had decreased survival compared to those who did not (P = 0.007). Significant risk factors for infection were higher risk MDS (hazard ratio [HR] = 2.7, 95% CI = 1.7–4.1, P < 0.0001), nadir absolute neutrophil count <500/mL (HR = 1.8, 95% CI = 1.2–2.7, P < 0.007), chronic obstructive pulmonary disease (HR = 2.6, 95% CI = 1.4–4.9, P < 0.003), history of other malignancy (HR 2.0, 95% CI = 1.3–3.1, P < 0.003), and autoimmune disease (HR 2.9, 95% CI = 1.4–6.0, P < 0.005). Age, nadir platelet count <20,000/mL, diabetes mellitus, and MDS treatment were not significant risk factors. Pneumonia was the most common infection, and bacteria the predominant pathogens.
Critical analysis of valganciclovir dosing and renal function on the development of cytomegalovirus infection in kidney transplantation
Authors: Posadas Salas M.A. , Taber D.J. , Chua E. , Pilch N. , Chavin K. , Thomas B.
Published: September 2013

Background

Cytomegalovirus (CMV) infection is one of the most common and important opportunistic infections following kidney transplantation. It causes significant morbidity and mortality. Valganciclovir (VGCV) is the drug of choice for prophylaxis to prevent CMV infection.

Methods

We conducted a post‐hoc analysis of a randomized controlled trial in 187 kidney transplant recipients to evaluate the impact of VGCV dosing and renal function on the development of CMV infection.

Results and conclusion

The results demonstrate that the following variables were independent risk factors for the development of CMV infection: high‐risk CMV serostatus (donor positive/recipient negative; hazard ratio [HR] 1.4, 95% confidence interval [CI] 1.46–5.28, P = 0.002); anti‐thymocyte globulin induction therapy (HR 2.1, 95% CI 1.08–4.07, P = 0.028); higher mean tacrolimus trough concentration (HR 1.4, 95% CI 1.09–1.74, P = 0.007); creatinine clearance <60 mL/min (HR 3.4, 95% CI 1.64–6.85, P = 0.001); and body weight >80 kg (HR 2.1, 95% CI 1.05–4.37, P = 0.037). VGCV dosing was appropriate for most patients, in those who did and did not develop CMV infection. These results strongly suggest that the currently recommended dose adjustments of VGCV dosing based on estimated renal function calculated using ideal body weight may underestimate the renal function of overweight patients and indirectly result in underexposure of overweight patients to VGCV. Based on these findings, further VGCV pharmacokinetic analyses are warranted in kidney transplant recipients with moderate‐to‐severe renal dysfunction.
Serum iron parameters in the early post‐transplant period and infection risk in kidney transplant recipients
Authors: Fernández‐Ruiz M. , López‐Medrano F. , Andrés A. , Morales J.M. , Lumbreras C. , San‐Juan R. , Polanco N. , González E. , Aguado J.M.
Published: September 2013

Background

The impact of iron metabolism on the risk of infectious complications has been demonstrated in various immunosuppressed populations. However, no previous studies have assessed this potential association in kidney transplant (KT) recipients.

Methods

We prospectively analyzed 228 patients undergoing KT at our institution from November 2008 to February 2011. Serum iron parameters (iron level, ferritin, total iron‐binding capacity, unsaturated iron‐binding capacity, transferrin, and transferrin saturation) were assessed within the first 2 weeks after transplantation (median interval, 3 days; interquartile [Q1–Q3] range, 1–6 days), and before the occurrence of the first infectious episode (median interval, 26 days; Q1–Q3 range, 11–76 days). Primary outcome was the occurrence of any episode of infection during the first year. Multivariate‐adjusted hazard ratios (aHRs) were estimated by Cox regression models.

Results

Patients with ferritin level ≥500 ng/mL had higher incidence rates (per 1000 transplant‐days) of overall infection (P = 0.017), bacterial infection (P = 0.002), and bloodstream infection (P = 0.011) during the first post‐transplant year. One‐year infection‐free survival rate was lower in these recipients (26% vs. 41%; P = 0.004). On multivariate analysis, after adjusting for potential confounders, ferritin emerged as an independent predictor of overall infection (aHR [per unitary increment], 1.001; P = 0.006), and bacterial infection (aHR [per unitary increment], 1.001; P = 0.020).

Conclusion

Monitoring of serum iron parameters in the early post‐transplant period may be useful in predicting the occurrence of infection in KT recipients, although further studies should be carried out to confirm this preliminary finding.
Comparison of heparinized saline and 0.9% sodium chloride for maintaining peripheral intravenous catheter patency in dogs
Authors: Ueda Yu , Odunayo Adesola , Mann F.A.
Published: September 2013

Objective

To determine whether heparinized saline would be more effective in maintaining the patency of peripheral IV catheters in dogs compared to 0.9% sodium chloride.

Design

Prospective blinded randomized study.

Setting

University Veterinary Teaching Hospital.

Animals

Thirty healthy purpose bred dogs, intended for use in the junior surgery laboratory, were utilized. The dogs were randomized into 1 of 3 groups, 2 treatment groups and a control group.

Interventions

An 18‐Ga cephalic catheter was placed in the cephalic vein of each dog. Each dog in the treatment group had their catheter flushed with either 10 IU/mL heparinized saline or 0.9% sodium chloride every 6 hours for 42 hours. The dogs in the control group did not have their catheters flushed until the end of the study period. Immediately prior to flushing catheters, each catheter was evaluated for patency by aspiration of blood and the catheter site was evaluated for phlebitis.

Measurements and Main Results

All dogs in the heparinized saline and 0.9% sodium chloride group had catheters that flushed easily at each evaluation point. More dogs in the saline group had catheters from which blood could not be aspirated, but there was no significant difference between these groups. All dogs in the control group had catheters that flushed easily at the end of the assigned 6 hour interval except in 1 dog. Phlebitis was not detected in any dog.

Conclusions

Flushes of 0.9% sodium chloride were found to be as effective as 10 IU/mL heparinized saline flushes in maintaining patency of 18‐Ga peripheral venous catheters in dogs for up to 42 hours. For peripheral catheters placed with the intention of performing serial blood draws, heparinized flushes may be warranted.
Computations of Particle-Laden Turbulent Jet Flows Based on Eulerian Model
Authors: Patro Pandaba , Dash Sukanta K.
Published: September 2013

Numerical simulations using an Eulerian two-fluid model were performed for spatially developing, two-dimensional, axisymmetric jets issued from a 30-mm-diameter circular nozzle. The nozzle was simulated separately for various flow conditions to get fully developed velocity profiles at its exit. The effect of interparticle collisions in the nozzle gives rise to solids pressure and viscosity, which are modeled using kinetic theory of granular flows (KTGF). The particle sizes are in the range of 30 μm to 2 mm, and the particle loading is varied from 1 to 5. The fully developed velocity profiles are expressed by power law, U=Uc(1-(r/R))N. The exponent, N, is found to be 0.14 for gas phase, irrespective of particle sizes and particulate loadings. However, the solid-phase velocity varies significantly with the particle diameter. For particle sizes up to 200 μm, the exponent is 0.12. The center line velocity (Uc) of the solid phase decreases and, hence, the slip velocity increases as the particle size increases. For 1 mm and 2 mm size particles, the exponent is found to be 0.08 and 0.05, respectively. The developed velocity profiles of both the phases are used as the inlet velocities for the jet simulation. The modulations on the flow structures and turbulent characteristics of gas flow due to the solid particles with different particle sizes and loadings are investigated. The jet spreading and the decay of the centerline mean velocity are computed for all particle sizes and loadings considered under the present study. Additions of solid particles to the gas flow significantly modulate the gas turbulence in the nozzle as well as the jet flows. Fine particles suppress the turbulence, whereas coarse particles enhance it.
On the Implementation of Computational Methods for a Hyperbolic Two-Fluid Model
Authors: Chung Moon-Sun , Jung Youn-Gyu , Yi Sung-Jae
Published: September 2013

In this study, we focused on the implementation of numerical methods for a 2-fluid system including the surface tension effect in the momentum equations. This model consists of a complete set of 8 equations including 2-mass, 4-momentum, and 2-internal energy conservations having all real eigenvalues. Based on this equation system with upwind numerical method, we first make a pilot 2-dimensional computer code and then solve some benchmark problems in order to check whether this model and numerical method is able to properly analyze some fundamental two-phase flow systems or not.
Prediction of Tire Ground Interaction Using FEA Truck Tire Models
Authors: Ali Rustam , El-Gindy Moustafa , Dhillon Ranvir , Mukesh Trivedi , Öijer Fredrik , Johansson Inge
Published: September 2013

The advancement of computerized modeling has allowed for the creation of extensive pneumatic tire models. These models have been used to determine many tire properties and tire-road interaction parameters which are either prohibitively expensive or unavailable with physical models.

This paper focuses on the prediction of tire-ground interaction with emphasis on individual and combined effect of tire slip angle and camber angle at various operating parameters. The forces generated at tire contact such as rolling resistance, cornering force, aligning moment and overturning moment can be predicted and used to optimize the tire design parameters. In addition to above stated, the three-groove FEA truck tire model representing radial-ply tire of size 295/75R22.5 was used in vertical load deflection test to determine enveloping characteristics under various load conditions and inflation pressures.
Investigation on the Dynamics of an On-Board Rotor-Bearing System
Authors: Dakel Mzaki , Baguet Sébastien , Dufour Régis
Published: September 2013

In ship and aircraft turbine rotors, the rotating mass unbalance and the different movements of the rotor base are among the main causes of vibrations in bending. The goal of this paper is to investigate the dynamic behavior of an on-board rotor under rigid base excitations. The modeling takes into consideration six types of base deterministic motions (rotations and translations) when the kinetic and strain energies in addition to the virtual work of the rotating flexible rotor components are computed. The finite element method is used in the rotor modeling by employing the Timoshenko beam theory. The proposed on-board rotor model takes into account the rotary inertia, the gyroscopic inertia, the shear deformation of shaft as well as the geometric asymmetry of shaft and/or rigid disk. The Lagrange’s equations are applied to establish the differential equations of the rotor in bending with respect to the rigid base which represents a noninertial reference frame. The linear equations of motion display periodic parametric coefficients due to the asymmetry of the rotor and time-varying parametric coefficients due to the base rotational motions. In the proposed applications, the rotor mounted on rigid/elastic bearings is excited by a rotating mass unbalance associated with sinusoidal vibrations of the rigid base. The dynamic behavior of the rotor is analyzed by means of orbits of the rotor as well as fast Fourier transforms (FFTs).
A Micro-Scale Magnetic Tumbling Microrobot
Authors: Jing Wuming , Pagano Nicholas , Cappelleri David J.
Published: September 2013

This paper presents a magnetic tumbling microrobot design at the micro-scale. The microrobot has a dumbbell shape whose largest dimension is about 400 μm. When subjected to an exterior predefined magnetic field, the magnetic microagent performs a tumbling motion driven by the interacting magnetic forces and momentums. The magnetic field providing driven force is generated by a coil system consisting of five electromagnetic coils. Under the available driven field, we show that the prototype agent is able to tumble on various types of surfaces in both dry and fluid environments.
Bayesian Inference for the Demand of Engineering Products
Authors: Abbas Ali E. , Hazelrigg George A. , Alkindi Mahmood
Published: September 2013

Within the context of a profit making firm, the job of a design engineer is to choose design parameters and product attributes that maximize the expected utility of profit. To do this effectively, the engineer needs to have an estimate of the demand for the product as a function of its price and its attributes. The firm may conduct a survey to elicit consumer preferences for the product at a given price and would like to update their belief about demand given the survey data. The purpose of this paper is to present a Bayesian methodology for demand estimation that meets this need. The estimation process begins with a prior probability distribution of demand at a given price. Using Bayesian analysis, we show how to update demand for the product given various pieces of information such as market analysis, polls and a variety of other methods. We also discuss situations where consumers can demand multiple units of the product at the given price.
Motion Planning for Shape–Controlled Adaptable Buildings Resembling Topologically Closed–Loop Robotic Systems
Authors: Christoforou Eftychios G. , Müller Andreas , Phocas Marios C.
Published: September 2013

Shape–controlled adaptable building structures have a potential of superior performance and flexibility compared to traditional fixed–shape ones. A building concept is proposed consisting of a number of interconnected planar n–bar linkages performing coordinated motions thus resembling a system of cooperating closed–loop robotic manipulators. For shape control an “effective 4–bar” linkage concept is proposed. That is, each individual n–bar mechanism is equipped with one motion actuator, and at any time of motion its degrees–of–freedom are reduced to one through the selective locking of (n – 4) joints using brakes. Shape adjustments of the overall structure can be carried out through appropriate control sequences where in each step exactly four joints of each linkage are unlocked giving rise to an effective 4–bar system. Motion planning is considered together with the relevant limitations arising from singular configurations that need to be taken into account. The concept is demonstrated through simulation examples.
Clustering Function-Based Failure Analysis Results to Evaluate and Reduce System-Level Risks
Authors: Jensen David C. , Hoyle Christopher , Tumer Irem Y.
Published: September 2013

For complex, safety-critical systems failures due to component faults and system interactions can be catastrophic. One aspect of ensuring a safe system design is the analysis of the impact and risk of potential faults early in the system design process. This early design-stage analysis can be accomplished through function-based reasoning on a qualitative behavior simulation of the system. Reasoning on the functional effect of failures provides designers with the information needed to understand the potential impact of faults. This paper proposes three different methods for evaluating and grouping the results of a function failure analysis and their use in design decision-making. Specifically, a method of clustering failure analysis results based on consequence is presented to identify groups of critical failures. A method of clustering using Latent Class Analysis provides characterization of high-level, emergent system failure behavior. Finally, a method of identifying functional similarity provides lists of similar and identical functional effects to a system state of interest. These three methods are applied to the function-based failure analysis results of 677 single and multiple fault scenarios in an electrical power system. The risk-based clustering found three distinct levels of scenario functional impact. The Latent Class Analysis identified five separate failure modes of the system. Finally, the similarity grouping identified different groups of scenarios with identical and similar functional impact to specific scenarios of interest. The overall goal of this work is to provide a framework for making design decisions that decrease system risks.
Multiharmonic Analysis and Design of Shroud Friction Joints of Bladed Disks Subject to Microslip
Authors: Krack Malte , Herzog Anna , Panning-von Scheidt Lars , Wallaschek Jörg , Siewert Christian , Hartung Andreas
Published: September 2013

Vibration reduction of turbine blades by means of friction damping in shroud joints is a well-established technology in the field of turbomachinery dynamics. Three-dimensional contact constraints in the shroud coupling can induce highly nonlinear dynamics in the bladed disk assembly. Moreover, large normal contact stresses, which are typical for this application, necessitate the consideration of microslip effects.

This study focuses on the accurate prediction of the forced response of tuned bladed disks subject to friction joints. In order to account for extended friction interfaces, the contact area is discretized into several contact points. Microslip behavior is explicitly enforced by a non-uniform normal pressure distribution. Local elastic properties of the contact area are accurately captured in the reduced order model of the structure by employing a component mode synthesis method. The steady-state forced response is efficiently computed using a Multi-Harmonic Balance ansatz. Thus, it is possible to study and explain the occurrence of internal resonances. Planar Coulomb friction and unilateral normal contact conditions are considered in terms of the Dynamic Lagrangian formulation. The normal preload of the shroud interface is varied in order to study the effect on vibration amplitude and resonance frequency.
Design of a Large Scale Vertical Stabilizer Wind Tunnel Model for Active Flow Control Research
Authors: Saunders Glenn , Whalen Edward , Mooney Helen , Zaremski Sarah
Published: September 2013

The design, fabrication and installation of an approximately 1/6 scale model of an aircraft vertical stabilizer for research in Active Flow Control (AFC) is discussed. Highlighted are the unique design requirements of wind tunnel models, the specialized fabrication techniques employed to create them and the required close collaboration between industry, government and three academic institutions. The design of the model involves often competing constraints imposed by structural, instrumentation, aerodynamic, manufacturability and research-agenda considerations as well as cost and schedule. Instrumentation requires hundreds of pressure ports and six-axis force/torque sensing. Aerodynamic considerations necessitate high manufacturing precision, highly-skilled fabrication techniques and careful observance of model geometry throughout the design and fabrication processes. A scale model of a vertical stabilizer for AFC research was successfully designed, fabricated and deployed. The collaboratively designed model satisfies the structural, aerodynamic and research design constraints, and furthers the state of the art in Active Flow Control research.
Nonlinear Oscillation of Shell Workpiece in High Speed Milling Under 1:2 Internal Resonance Condition
Authors: Zhang Wei , Zhou Rui , Zu Jean W. , Wang Qian
Published: September 2013

We aim to study nonlinear dynamics of a shell-shaped workpiece during milling processes in this paper. The shell-shaped workpiece is modelled as a cantilever thin shell subjected to a cutting force with time-delay effects. The formulas of the cantilever shell were derived by the classical shell theory and the von Karman strain-displacement relations. The resulting differential equations are reduced to a two-degree-of-freedom nonlinear system ordinary differential equations by applying the Galerkin’s approach. The method of Asymptotic Perturbation method is used to obtain the averaged equations, which were dealt with the resonance cases of 1:2 internal resonance and principal parametric resonance. Dynamic behaviors are presented based on the numerical solutions. The results show that different time-delay parameters result in periodic motion, multiple periodic motion, and chaotic motion.
Improving the Performance of a Piezoelectric Energy Harvester Using a Tip Spring-Mass System
Authors: Zhu Yang , Barry Oumar , Su Weijiun , Zu Jean
Published: September 2013

Vibration-based energy harvesting using piezoelectric materials has gained considerable attention over the past decade. Currently, most piezoelectric energy harvesters (PEHs) are single resonance frequency based. The performance of a single-resonance PEH is often limited to only one resonance frequency. This paper discusses the possibility of improving the performance of a bimorph PEH by tuning the PEH using a spring-mass system attached to the bimorph’s free end. Through adding the spring-mass system, the PEH’s resonance frequency can be tuned to match the ambient vibration frequency, and its voltage/power-generating capability can be improved. An electromechanical model of the PEH is derived based on the Lagrange multiplier method. The model is then used in a harmonic base excitation case study, and the coupled electromechanical outputs are discussed. Simulation results show that the spring-mass attachment can create two resonant frequencies, making the PEH capable of working efficiently at two different frequencies in a low-frequency level. It is also shown that by properly selecting the spring stiffness and the mass, the voltage and power output of the PEH can be greatly increased as compared to a single bimorph without the spring-mass system.
Modeling Torque Converter Characteristics in Automatic Drivelines: Lock-up Clutch and Engine Braking Simulation
Authors: Adibi Asl Hadi , Lashgarian Azad Nasser , McPhee John
Published: September 2013

A torque converter, which is a hydrodynamic clutch in automatic transmissions, transmits power from the engine shaft to the transmission shaft either by dynamically multiplying the engine torque or by rigidly coupling the engine and transmission shafts. The torque converter is a critical element in the automatic driveline, and it affects the vehicle’s fuel consumption and longitudinal dynamics.

This paper presents a math-based torque converter model that is able to capture both transient and steady-state characteristics. The torque converter is connected to a mean-value engine model, transmission model, and longitudinal dynamics model in the MapleSim environment, which uses the advantages of an acausal modeling approach. A lock-up clutch is added to the torque converter model to improve the efficiency of the powertrain in higher gear ratios, and its effect on the vehicle longitudinal dynamics (forward velocity and acceleration) is studied.

We show that the proposed model can capture the transition from the forward flow to the reverse flow operations during engine braking or coasting. The simulation results also show that the engine braking phenomenon (due to the flow reversal) can effectively assist the braking system to slow down the vehicle.