bluuebunny/crossref_metadata_2025 huggingface dataset:
Stem cells derived from “inflamed” and healthy periodontal ligament tissues and their sheet functionalities: a patient‐matched comparison
Authors: Tang Hao‐Ning , Xia Yu , Yu Yang , Wu Rui‐Xin , Gao Li‐Na , Chen Fa‐Ming
Published: December 2015

Aim

The aim of this study was to compare the properties of stem cells derived from “inflamed” and healthy periodontal ligament (PDL) tissues from patient‐matched groups.

Material and Methods

Patient‐matched stem cells derived from root‐attached “inflamed” and healthy PDL tissues from six donors, termed I‐PDLSCs and H‐PDLSCs, respectively, were investigated with regard to their stem cell properties, immunomodulatory effects and capacity to form robust cell sheets for therapeutic applications.

Results

We found that cells derived from both sources exhibited typical mesenchymal stem cell (MSC) characteristics. However, compared with H‐PDLSCs, I‐PDLSCs demonstrated an increased capacity to proliferate, a greater potential to migrate and a decreased capacity to differentiate into osteoblasts in vitro. When I‐PDLSCs and H‐PDLSCs were co‐cultured with peripheral blood mononuclear cells, the MSCs derived from “inflamed” PDL tissues exhibited impaired immunomodulation. Although I‐PDLSCs led to increased collagen type I, periostin and integrin β1 content in the matrix, the cell sheets formed by I‐PDLSCs were dysfunctional due to their impaired osteogenic/chondrogenic differentiation and tissue regeneration.

Conclusions

These data provide additional evidence that I‐PDLSCs are functionally compromised compared with H‐PDLSCs. Nonetheless, their dominant abundance in the available tissues indicates that stem cells derived from damaged teeth extracted due to periodontitis warrant further exploration.
Resolving the phylogenetic relationship between Chlamydomonas sp. UWO 241 and Chlamydomonas raudensis sag 49.72 (Chlorophyceae) with nuclear and plastid DNA sequences
Authors: Possmayer Marc , Gupta Rajesh K. , Szyszka‐Mroz Beth , Maxwell Denis P. , Lachance Marc‐André , Hüner Norman P.A. , Smith David Roy
Published: December 2015

The Antarctic psychrophilic green alga Chlamy‐domonas sp. UWO 241 is an emerging model for studying microbial adaptation to polar environments. However, little is known about its evolutionary history and its phylogenetic relationship with other chlamydomonadalean algae is equivocal. Here, we attempt to clarify the phylogenetic position of UWO 241, specifically with respect to Chlamydomonas rau‐densis SAG 49.72. Contrary to a previous report, we show that UWO 241 is a distinct species from SAG 49.72. Our phylogenetic analyses of nuclear and plastid DNA sequences reveal that UWO 241 represents a unique lineage within the Moewusinia clade (sensu Nakada) of the Chlamydomonadales (Chlorophyceae, Chlorophyta), closely affiliated to the marine species Chlamydomonas parkeae SAG 24.89.
Swimming patterns of the quadriflagellate Tetraflagellochloris mauritanica (Chlamydomonadales, Chlorophyceae)
Authors: Barsanti Laura , Coltelli Primo , Evangelista Valtere , Frassanito Anna Maria , Gualtieri Paolo
Published: December 2015

Chlamydomonadales are elective subjects for the investigation of the problems related to locomotion and transport in biological fluid dynamics, whose resolution could enhance searching efficiency and assist in the avoidance of dangerous environments. In this paper, we elucidate the swimming behavior of Tetraflagellochloris mauritanica, a unicellular–multicellular alga belonging to the order Chlamydomonadales. This quadriflagellate alga has a complex swimming motion consisting of alternating swimming phases connected by in‐place random reorientations and resting phases. It is capable of both forward and backward swimming, both being normal modes of swimming. The complex swimming behavior resembles the run‐and‐tumble motion of peritrichous bacteria, with in‐place reorientation taking the place of tumbles. In the forward swimming, T. mauritanica shows a very efficient flagellar beat, with undulatory retrograde waves that run along the flagella to their tip. In the backward swimming, the flagella show a nonstereotypical synchronization mode, with a pattern that does not fit any of the modes present in the other Chlamydomonadales so far investigated.
Self‐Reported Physical Activity Among American Indian Adults From Two Diverse Regions
Authors: Roberts Erica Blue , Fleischhacker Sheila , Pardilla Marla , Treuth Margarita , Gadhoke Preety , Christiansen Karina , Gittelsohn Joel
Published: December 2015

Purpose

Physical activity may be a protective factor against the disproportionate rates of chronic diseases faced by American Indians. Nevertheless, few studies report any cultural adoptions made to capture physical activity behaviors among this hard‐to‐reach population. Existing studies reporting the prevalence of physical activity among American Indians are often aggregated and tend to obscure regional, local, and tribal‐level variations. This study examines the prevalence of physical activity and inactivity levels, along with associated factors, among rural dwelling American Indian adults from 2 distinct regions.

Methods

Baseline self‐reported data were collected using a culturally modified version of the International Physical Activity Questionnaire (IPAQ) short form during the Obesity Research Prevention and Evaluation of Intervention Effectiveness in Native North Americans trial (OPREVENT) among rural American Indian adults (aged 18‐75 years) from 5 tribal communities in Michigan and New Mexico.

Findings

Most participants were classified as moderately physically active (43.5%), and the majority reported access to physical activity facilities (83.5%). Michigan participants reported engaging in more moderate and total physical activity than those in New Mexico (P < .001) and reported spending less time sitting (P < .001).

Conclusions

Differences in physical activity among the American Indian communities may be due to regional variations in occupations, climate, and tribal and community support and infrastructure. The unexpected high level of activity evokes uncertainty in the accuracy and appropriateness of the data collection instrument. Research is needed to understand culturally appropriate approaches to measure physical activity and inactivity among rural American Indians.
Integrating nap and night‐time sleep into sleep patterns reveals differential links to health‐relevant outcomes
Authors: Devine Jaime K. , Wolf Jutta M.
Published: December 2015

Both night‐time sleep and nap behaviour have been linked consistently to health outcomes. Although reasons for napping are usually tied to night‐time sleep, the majority of studies assess their effects independently. The current study thus aimed to examine the health relevance of patterns of sleep behaviour that take into account both night‐time and daytime sleep habits. Night‐time sleep, recorded during 7 days via actigraphy from 313 participants (aged 34–82 years) of the Midlife in the United States II Biomarker study, was assessed. Blood and urine specimens were assayed for noradrenaline, interleukin‐6 and C‐reactive protein. Participants self‐reported nap behaviour, depressive symptoms, perceived chronic stress and the presence of medical symptoms and conditions. Overall, nappers (n = 208) showed elevated waist–hip ratios, C‐reactive protein and interleukin‐6 levels compared to non‐nappers and reported more physiological symptoms and conditions (all P ≤ 0.019). Within nappers, cluster analysis revealed three patterns of sleep behaviour—infrequent nappers with good night‐time sleep, frequent nappers with good night‐time sleep and nappers with poor night‐time sleep. Nappers with poor night‐time sleep thereby exhibited elevated noradrenaline levels, depressive symptoms and perceived stress scores compared to other groups (all P ≤ 0.041). These findings support the idea that nap–health relationships are complex, in that frequency of napping and accumulation of nap sleep is not related linearly to health consequences. Assessing nap behaviour in conjunction with night‐time sleep behaviour appeared crucial to elucidate further the health relevance of napping, particularly in terms of psychological health outcomes, including chronic stress and depressive symptoms.
Ungulate behavioral responses to the heterogeneous road‐network of a touristic protected area in Africa
Authors: Mulero‐Pázmány M. , D'Amico M. , González‐Suárez M.
Published: December 2015

Understanding how wildlife responds to road and traffic is essential for effective conservation. Yet, not many studies have evaluated how roads influence wildlife in protected areas, particularly within the large iconic African National Parks where tourism is mainly based on sightings from motorized vehicles with the consequent development and intense use of roads. To reduce this knowledge gap, we studied the behavioral response and local spatial distribution of impala Aepyceros melampus along the heterogeneous (with variation in road surface type and traffic intensity) road‐network of Kruger National Park (KNP, South Africa). We surveyed different types of roads (paved and unpaved) recording the occurrence of flight responses among sighted impala and describing their local spatial distribution (in relation to the roads). We observed relatively few flight responses (19.5% of 118 observations), suggesting impalas could be partly habituated to vehicles in KNP. In addition, impala local distribution is apparently unaffected by unpaved roads, yet animals seem to avoid the close proximity of paved roads. Overall, our results suggest a negative, albeit small, effect of traffic intensity, and of presence of pavement on roads on the behavior of impala at KNP. Future studies would be necessary to understand how roads influence other species, but our results show that even within a protected area that has been well‐visited for a long time, wildlife can still be affected by roads and traffic. This result has ecological (e.g., changes in spatial distribution of fauna) and management implications (e.g., challenges of facilitating wildlife sightings while minimizing disturbance) for protected areas where touristic activities are largely based on driving.
Analysis of salicylic acid‐dependent pathways in Arabidopsis thaliana following infection with Plasmodiophora brassicae and the influence of salicylic acid on disease
Authors: Lovelock David A. , Šola Ivana , Marschollek Sabine , Donald Caroline E. , Rusak Gordana , van Pée Karl‐Heinz , Ludwig‐Müller Jutta , Cahill David M.
Published: December 2015

Salicylic acid (SA) biosynthesis, the expression of SA‐related genes and the effect of SA on the Arabidopsis–Plasmodiophora brassicae interaction were examined. Biochemical analyses revealed that, in P. brassicae‐infected Arabidopsis, the majority of SA is synthesized from chorismate. Real‐time monitored expression of a gene for isochorismate synthase was induced on infection. SA can be modified after accumulation, either by methylation, improving its mobility, or by glycosylation, as one possible reaction for inactivation. Quantitative reverse transcription‐polymerase chain reaction (qPCR) confirmed the induction of an SA methyltransferase gene, whereas SA glucosyltransferase expression was not changed after infection. Col‐0 wild‐type (wt) did not provide a visible phenotypic resistance response, whereas the Arabidopsis mutant dnd1, which constitutively activates the immune system, showed reduced gall scores. As dnd1 showed control of the pathogen, exogenous SA was applied to Arabidopsis in order to test whether it could suppress clubroot. In wt, sid2 (SA biosynthesis), NahG (SA‐deficient) and npr1 (SA signalling‐impaired) mutants, SA treatment did not alter the gall score, but positively affected the shoot weight. This suggests that SA alone is not sufficient for Arabidopsis resistance against P. brassicae. Semi‐quantitative PCR revealed that wt, cpr1, dnd1 and sid2 showed elevated PR‐1 expression on P. brassicae and SA + P. brassicae inoculation at 2 and 3 weeks post‐inoculation (wpi), whereas NahG and npr1 showed no expression. This work contributes to the understanding of SA involvement in the Arabidopsis–P. brassicae interaction.
A test of the ‘one‐point method’ for estimating maximum carboxylation capacity from field‐measured, light‐saturated photosynthesis
Authors: De Kauwe Martin G. , Lin Yan‐Shih , Wright Ian J. , Medlyn Belinda E. , Crous Kristine Y. , Ellsworth David S. , Maire Vincent , Prentice I. Colin , Atkin Owen K. , Rogers Alistair , Niinemets Ülo , Serbin Shawn P. , Meir Patrick , Uddling Johan , Togashi Henrique F. , Tarvainen Lasse , Weerasinghe Lasantha K. , Evans Bradley J. , Ishida F. Yoko , Domingues Tomas F.
Published: December 2015

Simulations of photosynthesis by terrestrial biosphere models typically need a specification of the maximum carboxylation rate (Vcmax). Estimating this parameter using A–Ci curves (net photosynthesis, A, vs intercellular CO2 concentration, Ci) is laborious, which limits availability of Vcmax data. However, many multispecies field datasets include net photosynthetic rate at saturating irradiance and at ambient atmospheric CO2 concentration (Asat) measurements, from which Vcmax can be extracted using a ‘one‐point method’.

We used a global dataset of A–Ci curves (564 species from 46 field sites, covering a range of plant functional types) to test the validity of an alternative approach to estimate Vcmax from Asat via this ‘one‐point method’.

If leaf respiration during the day (Rday) is known exactly, Vcmax can be estimated with an r2 value of 0.98 and a root‐mean‐squared error (RMSE) of 8.19 μmol m−2 s−1. However, Rday typically must be estimated. Estimating Rday as 1.5% of Vcmax, we found that Vcmax could be estimated with an r2 of 0.95 and an RMSE of 17.1 μmol m−2 s−1.

The one‐point method provides a robust means to expand current databases of field‐measured Vcmax, giving new potential to improve vegetation models and quantify the environmental drivers of Vcmax variation.
Mood instability and impulsivity as trait predictors of suicidal thoughts
Authors: Peters Evyn M. , Balbuena Lloyd , Marwaha Steven , Baetz Marilyn , Bowen Rudy
Published: December 2015

Objectives

Impulsivity, the tendency to act quickly without adequate planning or concern for consequences, is a commonly cited risk factor for suicidal thoughts and behaviour. There are many definitions of impulsivity and how it relates to suicidality is not well understood. Mood instability, which describes frequent fluctuations of mood over time, is a concept related to impulsivity that may help explain this relationship. The purpose of this study was to determine whether impulsivity could predict suicidal thoughts after controlling for mood instability.

Methods

This study utilized longitudinal data from the 2000 Adult Psychiatric Morbidity Survey (N = 2,406). There was a time interval of 18 months between the two waves of the study. Trait impulsivity and mood instability were measured with the Structured Clinical Interview for DSM‐IV Axis II Personality Disorders. Logistic regression analyses were used to evaluate baseline impulsivity and mood instability as predictors of future suicidal thoughts.

Results

Impulsivity significantly predicted the presence of suicidal thoughts, but this effect became non‐significant with mood instability included in the same model.

Conclusions

Impulsivity may be a redundant concept when predicting future suicidal thoughts if mood instability is considered. The significance is that research and therapy focusing on mood instability along with impulsivity may be useful in treating the suicidal patient.

Practitioner points

Mood instability and impulsivity both predict future suicidal thoughts.

Impulsivity does not predict suicidal thoughts after controlling for mood instability.

Assessing and treating mood instability could be important aspects of suicide prevention and risk management.
Timing of Haemophilus influenzae type b vaccination after cardiac surgery
Authors: Takanashi Manabu , Ogata Shohei , Honda Takashi , Nomoto Keiko , Mineo Eri , Kitagawa Atsushi , Ando Hisashi , Kimura Sumito , Nakahata Yayoi , Oka Norihiko , Miyaji Kagami , Ishii Masahiro
Published: December 2015

Background

The best time for vaccination in infants with congenital heart disease (CHD) after cardiopulmonary bypass (CPB) surgery is unclear, but it is important to prevent Haemophilus influenzae type b (Hib) infection in infants with CHD after CPB surgery. To identify the best time for Hib vaccination in infants with CHD after CPB surgery, we investigated the immunological status, and the efficacy and safety of Hib vaccination after CPB surgery.

Methods

Sixteen subjects who underwent surgical correction of ventricular septal defect with CPB were investigated. Immunological status and cytokines were analyzed before surgery, 2 months after surgery, and before Hib booster vaccination. Hib‐specific IgG was also measured to evaluate the effectiveness of vaccination.

Results

Immunological status before and 2 months after surgery (e.g. whole blood cells and lymphocyte subset profile) was within the normal range and no subjects had hypercytokinemia. Additionally, all subjects who received Hib vaccination at 2–3 months after CPB surgery had effective serum Hib‐specific IgG level for protection against Hib infection without any side‐effects.

Conclusions

CPB surgery does not influence acquired immunity and Hib vaccination may be immunologically safe to perform at 2 months after CPB surgery. Hib vaccination at 2–3 months after CPB surgery was effective in achieving immunization for infants with simple left–right shunt‐type CHD.
Using chromosomal data in the phylogenetic and molecular dating framework: karyotype evolution and diversification in Nierembergia (Solanaceae) influenced by historical changes in sea level
Authors: Acosta M. C. , Moscone E. A. , Cocucci A. A.
Published: December 2015

Karyotype data within a phylogenetic framework and molecular dating were used to examine chromosome evolution in Nierembergia and to infer how geological or climatic processes have influenced in the diversification of this solanaceous genus native to South America and Mexico. Despite the numerous studies comparing karyotype features across species, including the use of molecular phylogenies, to date relatively few studies have used formal comparative methods to elucidate chromosomal evolution, especially to reconstruct the whole ancestral karyotypes. Here, we mapped on the Nierembergia phylogeny one complete set of chromosomal data obtained by conventional staining, AgNOR‐, C‐ and fluorescent chromosome banding, and fluorescent in situ hybridisation. In addition, we used a Bayesian molecular relaxed clock to estimate divergence times between species. Nierembergia showed two major divergent clades: a mountainous species group with symmetrical karyotypes, large chromosomes, only one nucleolar organising region (NOR) and without centromeric heterochromatin, and a lowland species group with asymmetrical karyotypes, small chromosomes, two chromosomes pairs with NORs and centromeric heterochromatin bands. Molecular dating on the DNA phylogeny revealed that both groups diverged during Late Miocene, when Atlantic marine ingressions, called the ‘Paranense Sea’, probably forced the ancestors of these species to find refuge in unflooded areas for about 2 Myr. This split agrees with an increased asymmetry and heterochromatin amount, and decrease in karyotype length and chromosome size. Thus, when the two Nierembergia ancestral lineages were isolated, major divergences occurred in chromosomal evolution, and then each lineage underwent speciation separately, with relatively minor changes in chromosomal characteristics.
Facilitating Redundancy‐Oriented Management with Gene‐Therapy‐Oriented Management Against Disaster
Authors: Ha Kyoo‐Man
Published: December 2015

This article tests the hypothesis that “if redundancy‐oriented management has negative aspects, then it could be facilitated by gene‐therapy‐oriented management.” Negative aspects include disadvantages, misjudgments, or miscalculations. The article provides a newly revised principle of disaster management by studying gene‐therapy‐oriented management. Based on qualitative analysis, redundancy‐oriented and gene‐therapy‐oriented management are analyzed via five variables: governments, business, volunteers, households, and the international community. The article is valuable because an analytical frame on gene‐therapy‐oriented management is systematically reconceptualized for the field of disaster management via three elements: unhealthy proteins (problems or failed measures), a vector (new or modified solutions), and target cells (positive outcomes). In accepting the hypothesis, the key tenet is that stakeholders have to assist the progress of redundancy‐oriented management with gene‐therapy‐oriented management by paying attention to the genes of each disaster.
Red blood cell transfusion is associated with further bleeding and fresh‐frozen plasma with mortality in nonvariceal upper gastrointestinal bleeding
Authors: Subramaniam Kavitha , Spilsbury Katrina , Ayonrinde Oyekoya T. , Latchmiah Faye , Mukhtar Syed A. , Semmens James B. , Leahy Michael F. , Olynyk John K.
Published: December 2015

BACKGROUND

Blood products are commonly transfused for patients with nonvariceal upper gastrointestinal bleeding (NVUGIB). While concerns exist about further bleeding and mortality in subsets of patients receiving red blood cell (RBC) transfusion, the impact of non‐RBC blood products has not previously been systematically investigated. The aim of the study was to investigate the associations between blood products transfusion, further bleeding, and mortality after acute NVUGIB.

STUDY DESIGN AND METHODS

A retrospective cohort study examined further bleeding and 30‐day and 1‐year mortality in adult patients who underwent gastroscopy for suspected acute NVUGIB between 2008 and 2010 in three tertiary hospitals in Western Australia. Survival analysis was performed.

RESULTS

A total of 2228 adults (63% male) with 2360 hospital admissions for NVUGIB met the inclusion criteria. Median age at presentation was 70 years (range, 19–99 years). Thirty‐day mortality was 4.9% and 1‐year mortality was 13.9%. Transfusion of 4 or more units of RBCs was associated with greater than 10 times the odds of further bleeding in patients with a hemoglobin level of more than 90 g/L (odds ratio, 11.9; 95% confidence interval [CI], 3.1‐45.7; p ≤ 0.001), but was not associated with mortality. Administration of 5 or more units of fresh‐frozen plasma (FFP) was associated with increased 30‐day (hazard ratio, 2.8; 95% CI, 1.3‐5.9; p = 0.008) and 1‐year (hazard ratio, 2.6; 95% CI, 1.3‐5.0; p = 0.005) mortality after adjusting for coagulopathy, comorbidity, Rockall score, and other covariates.

CONCLUSION

In this large, multicenter study of NVUGIB, RBC transfusion was associated with further bleeding but not mortality, while FFP transfusion was associated with increased mortality in a subset of patients.
Mathematical model and calculation to predict the effect of prophylactic plasma transfusion on change in international normalized ratio in critically ill patients with coagulopathy
Authors: Pham Huy P. , Müller Marcella C. , Williams Lance A. , Juffermans Nicole P.
Published: December 2015

BACKGROUND

Plasma transfusion is often used prophylactically in patients with coagulopathy. However, the doses transfused may not be adequate to normalize hemostatic tests, which are commonly used as surrogate markers in practice. Currently, there is no reliable way to predict the posttransfusion international normalized ratio (INR) after plasma transfusion. Therefore, our aim was to develop and validate a formula that can reliably estimate post–plasma transfusion INR.

STUDY DESIGN AND METHODS

A compartmental model was developed using demographic (sex, height, weight) and laboratory variables (hematocrit [Hct], INRinitial, and plasma volume transfused). The formula was validated using a data set from a multicenter trial conducted between May 2010 and June 2013 in critically ill, nonbleeding patients with coagulopathy, receiving prophylactic plasma transfusions. INR was measured just before and immediately after plasma transfusion.

RESULTS

Initial plasma volume is calculated using the patient's Hct and blood volume (derived from Nadler's formula). The estimated immediate posttransfusion INR is then calculated as
urn:x-wiley:00411132:media:trf13447:trf13447-math-0001

There was a significant agreement between the model predictions and the actual INR measurements after transfusion. A total of 83% of the predictions were within the acceptable range of variation. Furthermore, there was no proportional difference or systemic bias between the predictions and the actual INR measurements.

CONCLUSION

This mathematical formula estimates posttransfusion INR after a certain volume of plasma transfusion with a good predictive ability. This formula, which only requires basic demographic and laboratory variables, may help the physicians to determine the volume of plasma required for a specific target INR in stable, nonbleeding patients.
The effect of stationary versus rocked storage of whole blood on red blood cell damage and platelet function
Authors: Yazer Mark H. , Glackin Emily M. , Triulzi Darrell J. , Alarcon Louis H. , Murdock Alan , Sperry Jason
Published: December 2015

BACKGROUND

Increasingly, cold‐stored whole blood (WB) is being considered for the resuscitation of civilian trauma patients. It is unclear whether the WB should be agitated to enhance the function of the platelets (PLTs) or whether agitation will cause RBC damage.

STUDY DESIGN AND METHODS

WB units were collected by standard procedures using a PLT‐sparing inline leukoreduction filter and stored between 1 and 6°C. On Storage Day 3 each unit was divided into 4 subunits that were stored under one of the following conditions for 21 days: unrocked, manually rocked once daily, continuously rocked end over end, or continuously rocked horizontally. From Day 3 to Day 10, hemolysis and the mechanical fragility index (MFI) for RBC injury were measured daily and again on Days 15 and 21 (n = 9‐16 units tested each time). On Days 4 and 10, rapid thromboelastogram (rTEG) measurements were performed (n = 8‐10 units tested each time).

RESULTS

Hemolysis and MFI increased significantly between Day 3 and Day 21 (p < 0.0001) for all RBC rocking conditions, as well as the unrocked units. Only the manually and horizontally rocked units demonstrated higher hemolysis (on Day 21) and MFI (starting on Day 10) compared to the unrocked units. Only the α‐angle and maximum amplitude in the end‐over‐end rocked units increased significantly between Day 4 and Day 10. There were no significant differences between the rocked and unrocked units on Day 10 for any rTEG variable.

CONCLUSIONS

Rocking does not appear to enhance in vitro PLT activity in cold‐stored WB and can lead to increased hemolysis.
Simulation of Dynamic Behavior and Prediction of Optimal Welding Current for Short-Circuiting Transfer Mode in GMAW
Authors: Wang Ying , Wang Lijun , Lv Xiaoqing
Published: December 2015

An improved “mass–spring” model to analyze the entire short-circuiting transfer (SCT) dynamic process based on the association between the arcing and circuiting phases has been proposed. This paper analyses the basic characteristics of displacement of the droplet mass center and oscillation velocity of droplet variation. In addition, the effect of welding current on the short-circuiting frequency is studied. The results of the simulations conducted agree well with the experimental results obtained. An analysis method for optimal welding current during SCT is also proposed, and the droplet transport stability is discussed. Simulation results demonstrate that the relative displacement of the droplet mass center and the average equivalent diameter of the transfer droplets are at a minimum under the optimal welding current condition. This research provides a reference for further simulation of the SCT process and useful guidance for the selection of optimum technics parameters.
Hybrid Direct Carbon Fuel Cell Performance With Anode Current Collector Material
Authors: Deleebeeck Lisa , Hansen Kent Kammer
Published: December 2015

The influence of the current collector on the performance of a hybrid direct carbon fuel cell (HDCFC), consisting of solid oxide fuel cell (SOFC) with a molten carbonate–carbon slurry in contact with the anode, has been investigated using current–voltage curves. Four different anode current collectors were studied: Au, Ni, Ag, and Pt. It was shown that the performance of the direct carbon fuel cell (DCFC) is dependent on the current collector materials, Ni and Pt giving the best performance, due to their catalytic activity. Gold is suggested to be the best material as an inert current collector, due to its low catalytic activity.
Compensated Conjugation and Gear Tooth Modification Design
Authors: Yu Bowen , Ting Kwun-lon
Published: December 2015

This paper addresses the fundamental issue on the conjugation for any gearing systems after tooth modification. It presents a rigorous theory on compensated conjugation for gear transmission error (TE) balance. The basic idea is that conjugation impaired by the loading condition can be compensated by modifying the transmission function. Thus, conjugation holds true after tooth modification. Because the modification is based on the universal concept of transmission rather than the tooth geometry, the proposed tooth modification method is universal rather than limited to involute or even planar gearing. A theorem about the continuity of motion and conjugate geometries is presented and proved for any desirable modification. The proposed theory is consistent with the standard manufacturing process for tooth modification. Tooth geometries and cutter geometries can be obtained after the theoretical TE function is designed. The proposed method is highlighted and demonstrated with an involute gear design, in which a convenient and practical method with a direct rack-cutter modification is presented and rigorously analyzed based on kinematics and differential geometry. Examples are presented to show the effectiveness of the methodology.
The Design Evolution of a Sensing and Force-Feedback Exoskeleton Robotic Glove for Hand Rehabilitation Application
Authors: Ben-Tzvi Pinhas , Danoff Jerome , Ma Zhou
Published: December 2015

This paper presents the design evolution of the sensing and force-feedback exoskeleton robotic (SAFER) glove with application to hand rehabilitation. The hand grasping rehabilitation system is designed to gather kinematic and force information from the human hand and then playback the motion to assist a user in common hand grasping movements, such as grasping a bottle of water. Grasping experiments were conducted where fingertip contact forces were measured by the SAFER glove. These forces were then modeled based on a machine learning approach to obtain the learned contact force distributions. Using these distributions, fingertip force trajectories were generated with a Gaussian mixture regression (GMR) method. To demonstrate the glove's effectiveness to manipulate the hand, experiments were performed using the glove to demonstrate grasping capabilities on several objects. Instead of defining a grasping force, contact force trajectories were used to control the SAFER glove in order to actuate a user's hand while carrying out a learned grasping task.
Design and Validation of a Carbon-Fiber Collapsible Hinge for Space Applications: A Deployable Boom
Authors: Piovesan Davide , Zaccariotto Mirco , Bettanini Carlo , Pertile Marco , Debei Stefano
Published: December 2015

This work presents an analysis and validation of a foldable boom actuated by tape-spring foldable elastic hinges for space applications. The analytical equations of tape-springs are described, extending the classical equations for isotropic materials to orthotropic carbon-fiber composite materials. The analytical equations which describe the buckling of the hinge have been implemented in a multibody simulation software where the hinge was modeled as a nonlinear elastic bushing and the boom as a rigid body. In the experimental phase, the boom was fabricated using a thin layer carbon-fiber composite tube, and the residual vibrations after deployment were experimentally tested with a triaxial accelerometer. A direct comparison of the simulation with the physical prototype pointed out the dangerous effect of higher order vibrations which are difficult to capture in simulation. We observed that while the vibrational spectra of simulations and experiments were compatible at low frequencies during deployment, a marked difference was observed at frequencies beyond 30 Hz. While difficult to model, higher order frequencies should be carefully accounted for in the design of self-deployable space structures. Indeed, if tape-springs are used as a self-locking mechanism, the higher vibrational modes could have enough energy to unlock the structure during operation.
Design of a Novel Flexible Endoscope—Cardioscope
Authors: Li Zheng , Zin Oo Min , Nalam Varun , Duc Thang Vu , Ren Hongliang , Kofidis Theodoros , Yu Haoyong
Published: December 2015

In this paper, we present a novel flexible endoscope (FE) which is well suited to minimally invasive cardiac surgery (MICS). It is named the cardioscope. The cardioscope is composed of a handle, a rigid shaft, a steerable flexible section, and the imaging system. The flexible section is composed of an elastic tube, a number of spacing disks, a constraint tube, and four wires. It employs the constrained wire-driven flexible mechanism (CWFM) with a continuum backbone, which enables the control of both the angulation and the length of the flexible section. Compared to other endoscopes, e.g., rigid endoscope (RE) and fixed-length FE, the cardioscope is much more dexterous. The cardioscope can bend over 180 deg in all directions, and the bending is decoupled from the distal tip position. Ex vivo tests show that the cardioscope is well suited to MICS. It provides much wider scope of vision than REs and provides good manipulation inside confined environments. In tests, the cardioscope successfully explored the full heart through a single hole, which shows that the design is promising. Despite being designed for MICS, the cardioscope can also be applied to other minimally invasive surgeries (MISs), such as laparoscopy, neurosurgery, transnasal surgery, and transoral surgery.
Module Design and Functionally Non-Isomorphic Configurations of the Hex-DMR II System
Authors: Davis Joshua D. , Sevimli Yunuscan , Eldridge Baxter R. , Chirikjian Gregory S.
Published: December 2015

Modular robots have captured the interest of the robotics community over the past several years. In particular, many modular robotic systems are reconfigurable, robust against faults, and low-cost due to mass production of a small number of different homogeneous modules. Faults in these systems are normally tolerated through redundancy or corrected by discarding damaged modules, which reduces the operational capabilities of the robot. To overcome these difficulties, we previously developed and discussed the general design constraints of a heterogeneous modular robotic system (Hex-DMR II) capable of autonomous team repair and diagnosis. In this paper, we discuss the design of each module, in detail, and present a new, novel elevator module. Then, we introduce a forestlike structure that enumerates every non-isomorphic, functional agent configuration of our system. Finally, we present a case study contrasting the kinematics and power consumption of two particular configurations during a mapping task.
Dynamical Behavior of a Capacitive Microelectromechanical System Powered by a Hindmarsh–Rose Electronic Oscillator
Authors: Simo Domguia U. , Abobda L. T. , Woafo P.
Published: December 2015

A capacitive microelectromechanical system (MEMS) powered by a Hindmarsh–Rose (HR)-like electronic oscillator is considered not only for actuation purposes but also to mimic the action of a natural pacemaker and nerves on a cardiac assist device or artificial heart. It is found that the displacement/flexion of the MEMS undergoes bursting and spiking oscillations resulting from the transfer of the electronic signal, when one varies the damping coefficient and the applied DC current.
Flaw Stability Considering Residual Stress for Aging Management of Spent Nuclear Fuel Multiple-Purpose Canisters
Authors: Lam Poh-Sang , Sindelar Robert L.
Published: December 2015

A typical multipurpose canister (MPC) is made of austenitic stainless steel and is loaded with spent nuclear fuel (SNF) assemblies. Because heat treatment for stress relief is not required for the construction of the MPC, the canister is susceptible to stress corrosion cracking in the weld or heat affected zone (HAZ) regions under long-term storage conditions. Logic for flaw acceptance is developed should crack-like flaws be detected by Inservice Inspection. The procedure recommended by API 579-1/ASME FFS-1, Fitness-for-Service, is used to calculate the instability crack length or depth by failure assessment diagram (FAD). It is demonstrated that the welding residual stress (RS) has a strong influence on the results.
The Limitations of Using “Ra” to Describe Surface Roughness
Authors: Goodhand Martin N. , Walton Karl , Blunt Liam , Lung Hang W. , Miller Robert J. , Marsden Reg
Published: December 2015

Current criteria used to determine whether rough surfaces affect skin friction typically rely on a single amplitude parameter to characterize the roughness. The most commonly used criteria relate the centerline averaged roughness, Ra, to an equivalent sandgrain roughness size, ks. This paper shows that such criteria are oversimplified and that Ra/ks is dependent on the roughness topography, namely, the roughness slope defined as the roughness amplitude normalized by the distance between roughness peaks, Ra/λ. To demonstrate the relationship, wake traverses were undertaken downstream of an aerofoil with various polished surfaces. The admissible roughness Reynolds number (ρ1u1Ra/μ1) at which the drag rose above the smooth blade case was determined. The results were used to demonstrate a 400% variation in Ra/ks over the roughness topographies tested. The relationship found held for all cases tested, except those where the roughness first initiated premature transition at the leading edge. In these cases, where the roughness was more typical of eroded aerofoils, the drag was found to rise earlier.
Model-Based Gain Scheduling Strategy for an Internal Model Control-Based Boost Pressure Controller in Variable Geometric Turbocharger System of Diesel Engines
Authors: Hong Seungwoo , Park Inseok , Sunwoo Myoungho
Published: December 2015

This paper proposes a model-based gain scheduling strategy of a Skogestad internal model control (SIMC)-based boost pressure controller for passenger car diesel engines. This gain scheduling strategy is proposed with a new scheduling variable to handle the nonlinear variable geometric turbocharger (VGT) plant characteristics. The scheduling variable is derived from the pressure ratio between the exhaust and intake manifolds and the exhaust air-to-fuel ratio to estimate the static gain of the VGT plant, which varies widely with change in the engine operating conditions. The proposed static gain model was designed with the scheduling variable, engine speed, and fuel injection quantity. Compared to the steady-state experimental data, the static gain model showed an R-squared value of 0.91. The boost pressure controller had the proportional-integral (PI) structure to allow for online calibration, and the PI gains were determined using the SIMC method. The proposed static gain model for the VGT plant was integrated into the SIMC control structure to obtain the appropriate control gains under wide engine operating area. The proposed control algorithm was compared with a fixed gain boost pressure controller through various step tests of the desired boost pressure. The fixed gain controller showed a large overshoot of 64% when the exhaust gas recirculation (EGR) operating condition was changed. In contrast, the proposed gain scheduled boost pressure controller reduced the overshoot to 12%. The model-based gain scheduling strategy successfully adjusted the control gains to achieve consistent control performance under various engine operating conditions.
Analysis of Conjugate Heat Transfer for a Combined Turbulent Wall Jet and Offset Jet
Authors: Mondal Tanmoy , Guha Abhijit , Kumar Das Manab
Published: December 2015

This paper presents a study of the conjugate heat transfer, involving conduction through a solid slab and turbulent convection in fluid, for a combined turbulent wall jet and offset jet flow using unsteady Reynolds averaged Navier–Stokes (URANS) equations. The conduction equation for the solid slab and convection equation for the fluid region are solved simultaneously satisfying the equality of temperature and heat flux at the solid–fluid interface. The fluid flow is complex because of the existence of periodically unsteady interaction between the two jets for the chosen ratio of jets separation distance to the jet width (i.e., d/w = 1). The heat transfer characteristics at the solid–fluid interface have been investigated by varying various important parameters within a feasible range: Reynolds number (Re = 10,000–20,000), Prandtl number (Pr = 1–4), solid-to-fluid thermal conductivity ratio (ks/kf = 1000–4000), and nondimensional solid slab thickness (s/w = 1–10). The bottom surface of the solid slab has been maintained at a constant temperature. The mean conjugate heat transfer characteristics indicate that the mean local Nusselt number along the interface is a function of flow (Re) as well as fluid (Pr) properties but is independent of solid properties (ks and s). However, the mean interface temperature and mean local heat flux along the interface always depend on all the aforementioned properties.
Vibration Isolation by an Actively Compliantly Mounted Sensor Applied to a Coriolis Mass-Flow Meter
Authors: (Bert) van de Ridder L. , Hakvoort Wouter B. J. , van Dijk Johannes , Lötters Joost C. , de Boer André
Published: December 2015

In this paper, a vibration isolated design of a Coriolis mass-flow meter (CMFM) is proposed by introducing a compliant connection between the casing and the tube displacement sensors, with the objective to obtain a relative displacement measurement of the fluid conveying tube, dependent on the tube actuation and mass-flow, but independent of external vibrations. The transfer from external vibrations to the relative displacement measurement is analyzed and the design is optimized to minimize this transfer. The influence of external vibrations on a compliant sensor element and the tube are made equal by tuning the resonance frequency and damping of the compliant sensor element and therefore the influence on the relative displacement measurement is minimized. The optimal tuning of the parameters is done actively by acceleration feedback. Based on simulation results, a prototype is built and validated. The validated design shows more than 24 dB reduction of the influence of external vibrations on the mass-flow measurement value of a CMFM, without affecting the sensitivity for mass-flow.
Effects of Droplet Diameter and Fluid Properties on the Leidenfrost Temperature of Polished and Micro/Nanostructured Surfaces
Authors: Hassebrook Anton , Kruse Corey , Wilson Chris , Anderson Troy , Zuhlke Craig , Alexander Dennis , Gogos George , Ndao Sidy
Published: December 2015

An experimental investigation of the effects of droplet diameters and fluid properties on the Leidenfrost temperature of polished and nano/microstructured surfaces has been carried out. Leidenfrost experiments were conducted on a stainless steel 304 polished surface and a stainless steel surface which was processed by a femtosecond laser to form above surface growth (ASG) nano/microstructures. Surface preparation resulted in a root mean square roughness (Rrms) of 4.8 μm and 0.04 μm on the laser processed and polished surfaces, respectively. To determine the Leidenfrost temperatures, the droplet lifetime method was employed using deionized (DI) water and HFE 7300DL. A precision dropper was used to vary the size of DI water droplets from 1.5 to 4 mm. The Leidenfrost temperature was shown to display increases as high as 100 °C on the processed surface over the range of droplet sizes, as opposed to a 40 °C increase on the polished surface. Average increases of the Leidenfrost temperature between polished and processed samples were as high as 200 °C. The experiment was repeated with HFE 7300DL; however, with no noticeable changes of the Leidenfrost temperatures with droplet size whether on the polished or the processed surface. The difference in the Leidenfrost behavior between DI water and HFE 7300DL and among the various droplet sizes can be attributed to the nature of the force balance and flow hydrodynamics at a temperature slightly below the Leidenfrost point (LFP).
Model-Based Switching-Crack Identification in a Jeffcott Rotor With an Offset Disk Integrated With an Active Magnetic Bearing
Authors: Singh Sandeep , Tiwari Rajiv
Published: December 2015

Vibration characteristics of a cracked Jeffcott rotor with an offset disk under the action of an active magnetic bearing (AMB), implemented to improve the radial positioning of the rotor, has been studied. Presence of the AMB suppresses the vibration induced due to the crack and unbalance; identification of the crack could be made by utilizing the vibration signal in conjunction with the controller current of the AMB. A four degrees-of-freedom (DOF) cracked rotor is modeled considering the gyroscopic effect due to the offset disk and a switching crack excitation function (SCEF) to introduce the breathing of crack. The dynamic condensation is applied to eliminate rotational displacements, which would pose practical difficulty in accurate measurement, from the system equations of motion (EOM) to develop an identification algorithm. Frequency domain transformation of the EOM is made with the help of the full spectrum analysis. An algorithm developed with the purpose of crack identification in the form of additive crack stiffness estimates the viscous damping, disk unbalance, and AMB constants as well. The algorithm has been tested for the measurement noise (in the displacement and the current) and bias errors in system parameters, and found to be robust.
A Mathematical Model to Analyze the Torque Caused by Fluid–Solid Interaction on a Hydraulic Valve
Authors: Frosina Emma , Senatore Adolfo , Buono Dario , Stelson Kim A.
Published: December 2015

In this paper, a three-dimensional (3D) computational fluid dynamics (CFD) methodology to improve the performance of hydraulic components will be shown, highlighting the importance that a study in the fluid mechanics field has for their optimization. As known, the valve internal geometry influences proportional spool valve hydraulic performance, axial flow forces, and spin effects on the spool. Axial flow forces and spin effects interact directly with the position control performance of a direct actuating closed-loop control valve, reducing its capability. The goal of this activity is the study of the torque on the spool induced by the flow and using a CFD 3D methodology to identify causes of this phenomenon and to find a general mathematical solution to minimize the spool spin effect. The baseline configuration and the new ones of the proportional four-way three-position closed-loop control spool valve have been studied with a mathematical model. The models were also validated by the experimental data performed in the Hydraulic Lab of the University of Naples. In particular, the tests allowed to measure the torque on the spool varying the oil flow rate, using a dedicated test bench layout where the spool was directly connected to a torque meter. Several geometries have been analyzed to find the best one to minimize spool spin behavior while maintaining an acceptable pressure drop. The study results confirmed the significant improvement of overall component performance.