bluuebunny/crossref_metadata_2025 huggingface dataset:
Growth and temperature relationships for juvenile fish species in seagrass beds: implications of climate change
Authors: Booth D. J. , Poulos D. E. , Poole J. , Feary D. A.
Published: November 2013

The effect of water temperature on growth responses of three common seagrass fish species that co‐occur as juveniles in the estuaries in Sydney (34° S) but have differing latitudinal ranges was measured: Pelates sexlineatus (subtropical to warm temperate: 27–35° S), Centropogon australis (primarily subtropical to warm temperate: 24–37° S) and Acanthaluteres spilomelanurus (warm to cool temperate: below 32° S). Replicate individuals of each species were acclimated over a 7 day period in one of three temperature treatments (control: 22° C, low: 18° C and high: 26° C) and their somatic growth was assessed within treatments over 10 days. Growth of all three species was affected by water temperature, with the highest growth of both northern species (P. sexlineatus and C. australis) at 22 and 26° C, whereas growth of the southern ranging species (A. spilomelanurus) was reduced at temperatures higher than 18° C, suggesting that predicted increase in estuarine water temperatures through climate change may change relative performance of seagrass fish assemblages.
Osteogenic relationship between the lateral plantar process and the peroneal tubercle in the human calcaneus
Authors: Gill Corey M. , Taneja Atul K. , Bredella Miriam A. , Torriani Martin , DeSilva Jeremy M.
Published: November 2013

The osteogenic relationship between the lateral plantar process and the peroneal tubercle has been an uncertainty for researchers over several decades. While some argue there to be no developmental relationship between these two calcaneal structures, others have suggested that there is an inverse relationship, the lateral plantar process forming from a part of the peroneal tubercle. However, no previous studies have offered quantitative measurements to test these hypotheses. In this study, we measured the size of the peroneal tubercle, retrotrochlear eminence, and the size and area of the lateral plantar process in 73 subjects using magnetic resonance imaging (MRI). Navicular height was measured using weight‐bearing radiographs as a measurement of longitudinal arch in 35 of these subjects. Age, body mass, and body mass index (BMI) were also recorded for all subjects. We determined that there was a significant positive correlation between the lateral plantar process and size of the peroneal tubercle, body mass, and BMI. Thus, assertions that there is an inverse relationship between the size of the lateral plantar process and the peroneal tubercle are here unfounded. We also determined there to be a positive correlation between the peroneal tubercle and both the size of the retrotrochlear eminence and the height of the navicular. In conclusion, we relate these novel findings to hominin fossil calcanei and discuss the evolutionary and biomechanical implications.
Relapse rates in chronic hepatitis B naïve patients after discontinuation of antiviral therapy with entecavir
Authors: Ridruejo E. , Marciano S. , Galdame O. , Reggiardo M. V. , Muñoz A. E. , Adrover R. , Cocozzella D. , Fernandez N. , Estepo C. , Mendizábal M. , Romero G. A. , Levi D. , Schroder T. , Paz S. , Fainboim H. , Mandó O. G. , Gadano A. C. , Silva M. O.
Published: November 2013

Registration studies show entecavir (ETV) to be effective and safe in NUC‐naïve patients with chronic hepatitis B, but relapse rates after treatment discontinuation have not been well established. Relapse rates and predictors of relapse were evaluated in naïve HBeAg‐positive and HBeAg‐negative patients treated with ETV. Treatment duration was defined according to international guidelines. Virological relapse was defined as reappearance in serum of hepatitis B virus (HBV) DNA to >2000 IU/mL after discontinuation of treatment. A hundred and sixty‐nine consecutive patients were treated for a median 181 weeks. 61% were HBeAg positive, 23% had cirrhosis, and mean HBV DNA level was 6.88 ± 1.74 log10 IU/mL. Ninety‐two per cent became HBV DNA negative; 71% of HBeAg+ve patients became HBeAg negative and 68% anti‐HBe positive; 14% became HBsAg negative and 13% anti‐HBs positive. At the end of the study, 36 patients discontinued treatment: one due to breakthrough associated with resistant variants and 35 (20%) due to sustained virological response; 33 of these patients developed HBeAg seroconversion and 18 HBsAg seroconversion. Median off‐treatment time was 69 weeks. Nine patients (26%), all HBeAg positive at baseline, developed virological relapse after a median 48 weeks off‐treatment, 3 of them showed HBeAg reversion and 4 lost anti‐HBe. No patient with HBsAg seroconversion relapsed. HBeAg clearance after week 48 of treatment was associated with an increase risk of relapse. After ETV discontinuation, HBsAg seroconversion was maintained in 100% of the patients, HBeAg seroconversion maintained in 90%, and virological relapse rate was 24%.
The pro‐fibrotic effects of pregnancy in a carbon‐tetrachloride‐induced liver injury in mouse model
Authors: Amer Johnny , Grifat Rami , Doron Sarit , Abu‐Tair Lina , Mruwat Rufayda , El‐Khatib Areej , Safadi Rifaat
Published: November 2013

Background & Aims

Immune cells interact with hepatic‐stellate‐cells (HSCs) in the development of liver fibrosis. Little is known about the influence of pregnancy on the development and progression of hepatic‐fibrosis. In this study, we explored the influence of pregnancy on progression of hepatic fibrosis.

Methods

Female mice (C57Blc) were induced by 4 injections of peritoneal carbon‐tetrachloride (CCl4) within 10 days, starting at day 10 of documented pregnancy. At end of experiment, serum samples were obtained for ALT and estradiol determination. Harvested livers were histological evaluated for liver injury and for protein αSMA expressions. Isolated intra‐hepatic lymphocytes were assessed by flow cytometry. Isolated lymphocytes and serum samples were in‐ vitro co‐cultured for 48 h with primary isolated naïve HSCs. Washed cells were analyzed for adherence (anti‐αSMA+/anti‐CD45 + ) and proliferations (CSFE).

Results

CCl4‐model for liver injury was well tolerated when induced in pregnancy similar to non‐pregnant state. Hepatic‐fibrosis (Masson Trichrome Stain, Sirius red stain and αSMA expressions) and necro‐inflammation (H&E stain and serum ALT levels) significantly increased in pregnancy. Increased liver injury was accompanied with pro‐fibrotic lymphocyte profile; CD8 subsets increased and NK cells decreased. HSCs activation significantly increased when in‐vitro cultured with lymphocytes from pregnant as compared to non‐pregnant fibrotic ones. Pro‐fibrotic profile was also explained by decreased NK activity (CD107a marker) and of their phagocytosis. Serum estradiol levels although elevated in fibrosis conditions of pregnancy was not associated with the pHSCs activations.

Conclusion

Liver fibrosis in our murine model was severe in pregnant model; via pro‐fibrotic lymphocyte and serum alterations.
Validation of the five‐variable Model for End‐stage Liver Disease (5vMELD) for prediction of mortality on the liver transplant waiting list
Authors: Myers Robert P. , Tandon Puneeta , Ney Michael , Meeberg Glenda , Faris Peter , Shaheen Abdel Aziz M. , Aspinall Alexander I. , Burak Kelly W.
Published: November 2013

Background

Modifications to the Model for End‐Stage Liver Disease (MELD) have been proposed to improve prioritization of liver transplant (LT) candidates. Using a U.S. database, we derived a revised MELD including sodium and albumin [5‐variable MELD (5vMELD)] that improved prediction of waiting list mortality. Our objectives were to confirm the association between hypoalbuminaemia and mortality and to externally validate 5vMELD in Canadian LT candidates.

Methods

Among adults registered on the LT waiting list at the University of Alberta (01/2000‐10/2009), Cox regression determined the association between albumin and 1‐year waiting list mortality. The discrimination of MELD, MELDNa and 5vMELD for predicting 1‐year mortality were compared using c‐statistics.

Results

Among 677 patients, 17% died and 51% underwent LT within 1 year of listing. Median serum albumin was 3.1 g/dl (IQR 2.6–3.6) and 70% of patients were hypoalbuminaemic (albumin <3.5 g/dl). One‐year mortality in patients with normal serum albumin and hypoalbuminaemia were 14% and 29% respectively (P = 0.004). For patients with serum albumin between 2.0 and 4.0 g/dl, an approximately linear, inverse relationship was observed between albumin and 1‐year mortality [adjusted hazard ratio (HR) 1.45; 95% CI 1.03–2.03; P = 0.03]. For this outcome, the c‐statistic of 5vMELD (0.778) was superior to those of MELD (0.754) and MELDNa (0.765) (both P ≤ 0.05).

Conclusions

Hypoalbuminaemia is an independent predictor of mortality on the LT waiting list. Compared with MELD and MELDNa, 5vMELD improves prediction of mortality suggesting that modification of these scores to include serum albumin should be considered as a means of prioritizing LT candidates.
Olfactory and behavioural responses of tabanid horseflies to octenol, phenols and aged horse urine
Authors: BALDACCHINO F. , MANON S. , PUECH L. , BUATOIS B. , DORMONT L. , JAY‐ROBERT P.
Published: November 2013

Electrophysiological and behavioural responses of females of two tabanid species, Tabanus bromius L. and Atylotus quadrifarius (Loew) (Diptera: Tabanidae), to ammonia, octenol (1‐octen‐3‐ol), phenols and aged horse urine were compared. Electroantennogram (EAG) responses in both species to octenol, 4‐methylphenol (4MP), 3‐propylphenol (3PP) and a phenol mixture (4MP and 3PP at a ratio of 16 : 1) increased in a dose‐dependent fashion. The most effective stimulus was 4MP and synergism between the two phenols may exist. Aged horse urine also elicited strong EAG responses in both species. Using gas chromatography–mass spectrometry (GC‐MS) analysis, we identified 29 compounds in horse urine, which included, in particular, ketones, fatty alcohols and phenols, among which 4MP was the most abundant component (˜ 80%). Trapping experiments were carried out using Nzi traps baited with various odours. Octenol and the phenol mixture in combination with ammonia increased catches of tabanids by 1.8–2.8 times relative to ammonia alone. Aged horse urine increased catches of T. bromius and A. quadrifarius by 2.2 and 4.1 times, respectively. The high attractiveness of aged horse urine, especially for A. quadrifarius, is not likely to derive from 4MP alone, but from the mixture of various active compounds used in host location.
Behind the scenes: the roles of reactive oxygen species in guard cells
Authors: Song Yuwei , Miao Yuchen , Song Chun‐Peng
Published: November 2013

Guard cells regulate stomatal pore size through integration of both endogenous and environmental signals; they are widely recognized as providing a key switching mechanism that maximizes both the efficient use of water and rates of CO2 exchange for photosynthesis; this is essential for the adaptation of plants to water stress. Reactive oxygen species (ROS) are widely considered to be an important player in guard cell signalling. In this review, we focus on recent progress concerning the role of ROS as signal molecules in controlling stomatal movement, the interaction between ROS and intrinsic and environmental response pathways, the specificity of ROS signalling, and how ROS signals are sensed and relayed. However, the picture of ROS‐mediated signalling is still fragmented and the issues of ROS sensing and the specificity of ROS signalling remain unclear. Here, we review some recent advances in our understanding of ROS signalling in guard cells, with an emphasis on the main players known to interact with abscisic acid signalling.

Contents

Summary
1121

I.
Introduction
1121

II.
Multiple signals for production and signalling integration of ROS in guard cells
1122

III.
Signal transduction pathway of ROS in guard cells
1125

IV.
Specificity of ROS signalling
1129

V.
Conclusions and prospects
1133

Acknowledgements
1134

References
1134
In Between Cultures
Authors: BHABHA HOMI
Published: November 2013

Going through a protracted period of transition since the end of the Cold War, the world order in the making is neither what was nor what it is yet to become. It is in “the middle of the future.”

To get our bearings in this uncertain transition, we explore the two grand post‐Cold War narratives—“The End of History” as posited by Francis Fukuyama and “The Clash of Civilizations” posited by the late Samuel Huntington. Mikhail Gorbachev looks back at his policies that brought the old order to collapse. The British philosopher John Gray critiques the supposed “universality” of liberalism and, with Homi Bhabha, sees a world of hybrid identities and localized cultures. The Singaporean theorist Kishore Mahbubani peels away the “veneer” of Western dominance. Amartya Sen, the economist and Nobel laureate, assesses whether democratic India or autocratic China is better at building “human capacity” in their societies.
The Contribution of Reactive Oxygen Species to the Photobleaching of Organic Fluorophores
Authors: Zheng Qinsi , Jockusch Steffen , Zhou Zhou , Blanchard Scott C.
Published: November 2013

Photoexcitation of fluorophores commonly used for biological imaging applications generates reactive oxygen species (ROS) which can cause bleaching of the fluorophore and damage to the biological system under investigation. In this study, we show that singlet oxygen contributes relatively little to Cy5 and ATTO 647N photobleaching at low concentrations in aqueous solution. We also show that Cy5 generates significantly less ROS when covalently linked to the protective agents, cyclooctatetraene (COT), nitrobenzyl alcohol (NBA) or Trolox. Such fluorophores exhibit enhanced photostability both in bulk solutions and in single‐molecule fluorescence measurements. While the fluorophores ATTO 647N and ATTO 655 showed greater photostability than Cy5 and the protective–agent‐linked Cy5 derivatives investigated here, both of ATTO 647N and ATTO 655 generated singlet oxygen and hydroxyl radicals at relatively rapid rates, suggesting that they may be substantially more phototoxic than Cy5 and its derivatives.
Regulation of cigarette smoke‐induced toll‐like receptor 4 expression by peroxisome proliferator‐activated receptor‐gamma agonists in bronchial epithelial cells
Authors: Yin Yan , Hou Gang , Li Er‐ran , Wang Qiu‐yue , Kang Jian
Published: November 2013

Background and objective

This study was designed to determine the effects of peroxisome proliferator‐activated receptor‐gamma (PPARγ) on airway inflammatory response to cigarette smoke (CS) exposure.

Methods

For the in vivo experiments, 50 male Wistar rats were randomly assigned to one of four groups and were exposed to CS and pretreatment with a PPARγ agonist, rosiglitazone or a vehicle (saline). PPARγ antagonist bisphenol A diglycidyl ether (BADGE) or saline was administered before rosiglitazone treatment. Leukotriene B4 (LTB4) and interleukin‐8 (IL‐8) were measured by enzyme‐linked immunosorbent assay. PPARγ and toll‐like receptor 4 (TLR4) expression levels were assessed by immunohistochemistry and real‐time polymerase chain reaction. For the in vitro experiments, human bronchial epithelial cells were stimulated with CS or phosphate buffer saline, pretreated with PPARγ agonist rosiglitazone or 15‐deoxy‐(Δ12,14)‐PG J2 before CS exposure. BADGE was administered prior to the agonist treatment. PPARγ, TLR4 and inhibitor of κB (IκBα) expression levels were assessed by Western bot.

Results

CS exposure decreased PPARγ expression, as well as increased IL‐8, LTB4 and TLR4 expression levels in bronchial epithelial cells in vivo and in vitro. Moreover, PPARγ ligands counteracted CS‐induced airway inflammation by reducing IL‐8 and LTB4 expression levels that are associated with TLR4 and nuclear factor‐kappa B (NF‐κB).

Conclusion

CS exposure increased the pro‐inflammatory activity of bronchial epithelial cells by affecting PPARγ expression. Moreover, PPARγ may play a significant role as a modulator of the TLR4‐dependent inflammatory pathway through NF‐κB in bronchial epithelial cells.
Respiratory syncytial virus induces leukotriene C4 synthase expression in bronchial epithelial cells
Authors: Sun Li‐hong , Chen Ai‐huan , Yang Zi‐feng , Chen Jason J. , Guan Wen‐da , Wu Jie‐ling , Qin Sheng , Zhong Nan‐shan
Published: November 2013

Background and objective

Respiratory syncytial virus (RSV) results in acute wheezing in infants and is frequently associated with recurrent wheezing. Although RSV‐induced wheezing clinically resembles that of asthma, corticosteroids are not equivalently effective in RSV‐associated wheezing. The study sought to determine the mechanisms of RSV‐induced wheezing by establishing an in vitro model of RSV‐infected human bronchial epithelial cells (16‐HBEC).

Methods

Leukotriene C4 synthase (LTC4S) messenger RNA (mRNA) expression in 16‐HBEC was detected using fluorescence quantitative polymerase chain reaction, and the relative level of LTC4S mRNA was expressed as quotient cycle threshold (qCt) based on the threshold cycle number value compared with that of β‐actin. Cysteinyl leukotrienes (CysLT) in culture supernatant were measured by enzyme‐linked immunosorbent assay. RSV‐infected 16‐HBEC was incubated with gradient concentration of budesonide (BUD) to assess its effects on LTC4S expression and CysLT secretion.

Results

RSV infection resulted in increased LTC4S mRNA expression between 48 and 96 h post‐infection. High level of CysLT was detected in the supernatant of RSV‐infected 16‐HBEC. BUD at concentrations of 10−10 to 10−5 mol/L did not significantly alter LTC4S mRNA expression.

Conclusions

RSV infection upregulated LTC4S expression in HBEC leading to increased CysLT secretion. Such induction was not attenuated by BUD, suggesting that CysLT might contribute to the pathogenesis of RSV‐induced wheezing.
Quick and Easy One-Step Parameter Estimation in Differential Equations
Authors: Hall Peter , Ma Yanyuan
Published: November 2013

Differential equations are customarily used to describe dynamic systems. Existing methods for estimating unknown parameters in those systems include parameter cascade, which is a spline-based technique, and pseudo-least-squares, which is a local-polynomial-based two-step method. Parameter cascade is often referred to as a ‘one-step method’, although it in fact involves at least two stages: one to choose the tuning parameter and another to select model parameters. We propose a class of fast, easy-to-use, genuinely one-step procedures for estimating unknown parameters in dynamic system models. This approach does not need extraneous estimation of the tuning parameter; it selects that quantity, as well as all the model parameters, in a single explicit step, and it produces root-n-consistent estimators of all the model parameters. Although it is of course not as accurate as more complex methods, its speed and ease of use make it particularly attractive for exploratory data analysis.
The Bayesian Bridge
Authors: Polson Nicholas G. , Scott James G. , Windle Jesse
Published: November 2013

We propose the Bayesian bridge estimator for regularized regression and classification. Two key mixture representations for the Bayesian bridge model are developed: a scale mixture of normal distributions with respect to an α-stable random variable; a mixture of Bartlett–Fejer kernels (or triangle densities) with respect to a two-component mixture of gamma random variables. Both lead to Markov chain Monte Carlo methods for posterior simulation, and these methods turn out to have complementary domains of maximum efficiency. The first representation is a well-known result due to West and is the better choice for collinear design matrices. The second representation is new and is more efficient for orthogonal problems, largely because it avoids the need to deal with exponentially tilted stable random variables. It also provides insight into the multimodality of the joint posterior distribution, which is a feature of the bridge model that is notably absent under ridge or lasso-type priors. We prove a theorem that extends this representation to a wider class of densities representable as scale mixtures of beta distributions, and we provide an explicit inversion formula for the mixing distribution. The connections with slice sampling and scale mixtures of normal distributions are explored. On the practical side, we find that the Bayesian bridge model outperforms its classical cousin in estimation and prediction across a variety of data sets, both simulated and real. We also show that the Markov chain Monte Carlo algorithm for fitting the bridge model exhibits excellent mixing properties, particularly for the global scale parameter. This makes for a favourable contrast with analogous Markov chain Monte Carlo algorithms for other sparse Bayesian models. All methods described in this paper are implemented in the R package BayesBridge. An extensive set of simulation results is provided in two on-line supplemental files.
Characterizing Teachers' Verbal Scaffolds to Guide Elementary Students' Creation of Scientific Explanations
Authors: Songer Nancy Butler , Shah Ashima Mathur , Fick Sarah
Published: November 2013

Scaffolding is a complicated construct that can take many forms, including both written and verbal forms. This research study focused on three elementary science classrooms where students were using a series of written scaffolds to guide explanation building. In each classroom, data were collected to document and study an additional type of scaffold, verbal scaffolds that the teachers provided to complement the written scaffolds. Findings suggested that some types of verbal scaffolds, such as navigational guidance, were universal and therefore cut across all three grade levels. On balance, other verbal scaffolds were more common with younger students in association with their first explanation‐building science unit, such as a verbal scaffold that turned an open‐ended question into a few multiple‐choice options. Through the characterization of the types and range of verbal scaffolds that teachers say, both in general and in response to audience, we can gain insights to inform both curricular design and professional development toward supported explanation building across target audience, time, and topic.
Evaluation of Erytra® fully automated analyser for Routine Use in Transfusion Laboratory
Authors: Chang C. , Brown M. , Davies L. , Pointon L. , Brown R. , Barker D.
Published: November 2013

Objective

To evaluate efficiency and performance of Erytra® analyser in comparison to the reference platform of the NBT immunohaematology laboratory (Bio‐Rad ID‐System).

Background

Moving to automation or semi‐automation is a major focus of transfusion centres. The Erytra® (Grifols) is a new fully automated walk‐away analyser with high volume processing capacity for pre‐transfusion testing, designed to be used with the unique 8‐column DG Gel® cards.

Study Design and Methods

A total of 2201 immunohaematological tests (1041 ABO/D grouping, 1041 antibody screening, 51 antibody identification, 45 newborns (ABO/D and DAT) and 23 crossmatches were performed on 1160 donor/patient whole blood samples. Erytra®'s performance was assessed by means of a stress test replicating the routine work of a hospital laboratory.

Results

Concordant results between the Erytra® and the reference method were obtained in 2195 (99·73 %) of the tests. There were only three discrepancies out of 6246 reactions (0·05%) in ABO/D grouping, all in the reverse group which did not mislead to group identification. Of the 1041 samples screened for antibody presence, Erytra® detected all the relevant antibodies [9 not detected weak prophylactic anti‐D were determined to be clinically nonsignificant (<0·1 IU mL−1)] while Bio‐Rad ID‐System missed one anti‐e and one anti‐Jka. Concordance for D grouping, crossmatching and newborns was 100%. Results of the simulated stress test exercise highlighted the capacity of Erytra® for absorbing into 4 h workloads equivalent to 24 h of routine.

Conclusions

Grifols' Erytra® analyser showed reliable high sensitivity, velocity and capacity to cope with high workload in the immunohaematology laboratory routine.
Hemolytic disease of the fetus and newborn caused by anti‐Lan
Authors: Brooks Sarah , Squires Jerry E.
Published: November 2013

Background

Antibodies to the high‐incidence red blood cell (RBC) antigen Lan (Langereis) are typically immunoglobulin G and have been shown to fix complement and cause hemolysis of Lan antigen–positive RBCs. Only three cases of hemolytic disease of the fetus and newborn (HDFN) have been reported involving anti‐Lan and all have been characterized as “mild.”

Case Report

A 26‐year‐old Hispanic female presented in her fifth pregnancy for routine obstetric care. Due to progressively rising anti‐Lan titers, middle cerebral artery (MCA) Dopplers were performed. At 32 weeks of gestation, the antibody titer had reached 128; the MCA Doppler indicated that fetal anemia was severe. An intrauterine transfusion with Lan antigen–negative RBCs was performed and a viable infant was delivered 25 days later.

Discussion

Three cases of HDFN associated with anti‐Lan have been previously reported. While these cases have been associated with somewhat variable serologic findings, none have resulted in fetal demise or severe symptomatology requiring pre‐ or postnatal intervention other than routine phototherapy. The current report, however, suggests that in some instances anti‐Lan can result in a more severe form of HDFN requiring more aggressive prenatal therapy.

Conclusion

In spite of previous case reports suggesting that anti‐Lan is associated with relatively mild HDFN, this case suggests that in some instances, this antibody can cause severe HDFN requiring prenatal intervention.
Comparison of antibody titers in donor specimens and associated AS‐1 leukoreduced donor units
Authors: Hill Elizabeth A. , Bryant Barbara J.
Published: November 2013

Background

Donor units with unexpected antibodies to red blood cell (RBC) antigens have transfusion restrictions and are often discarded by collection facilities. This study examined the antibody titer reduction in AS‐1 leukoreduced RBC (LR‐RBC) units and potential acceptability of these units for unrestricted transfusions.

Study Design and Methods

Donor specimens and AS‐1 LR‐RBC segment samples from donors with positive antibody screens and group O donors were analyzed. Antibody identifications were performed, and titer results from the matched serum samples and segment supernatants were compared.

Results

During the 5‐month study, 39 donor samples with positive antibody screens, five random group O donor samples, and the associated LR‐RBC unit segments were assessed. The median donor sample and segment supernatant titers were 4 and 1, respectively. Alloantibodies were undetectable in 28% of the donor segment supernatants. The median anti‐A and anti‐B titers in the group O donor samples were 128 and were reduced to 32 in the donor segment supernatants. All ABO and other antibodies were diluted by the AS‐1 to a titer of not more than 32.

Conclusion

Antibody titers in AS‐1 LR‐RBC units were significantly decreased compared to donor specimens and were lower than anti‐A and ‐B titers in group O AS‐1 LR‐RBC units, which are frequently transfused to non–group O recipients. If a “clinically significant” titer for donor alloantibodies was established, blood centers could determine eligibility of units for unrestricted transfusions. This would decrease unnecessary RBC wastage and increase units available for transfusion.
Cavitation Bubble Collapse Near a Heated Wall and Its Effect on the Heat Transfer
Authors: Liu Bin , Cai Jun , Huai Xiulan , Li Fengchao
Published: November 2013

In the present work, a numerical investigation on the mechanism of heat transfer enhancement by a cavitation bubble collapsing near a heated wall has been presented. The Navier–Stokes equations and volume of fluid (VOF) model are employed to predict the flow state and capture the liquid-gas interface. The model was validated by comparing with the experimental data. The results show that the microjet violently impinges on the heated wall after the bubble collapses completely. In the meantime, the thickness of the thermal boundary layer and the wall temperature decrease significantly within the active scope of the microjet. The fresh low-temperature liquid and the impingement brought by the microjet should be responsible for the heat transfer reinforcement between the heated wall and the liquid. In addition, it is found that the impingement width of the microjet on the heated wall always keeps 20% of the bubble diameter. And, the enhancement degree of heat transfer significantly depends on such factors as stand-off distance, saturated vapor pressure, and initial bubble radius.
Evaluation of Foil Bearing Performance and Nonlinear Rotordynamics of 120 kW Oil-Free Gas Turbine Generator
Authors: Kim Daejong , Lee An Sung , Choi Bum Seog
Published: November 2013

This paper presents a design approach of air foil bearings (AFBs) for a 120 kWe gas turbine generator, which is a single spool configuration with gas generator turbine and alternator rotor connected by a diaphragm coupling. A total of four radial AFBs support the two rotors, and one set of double acting thrust foil bearing is located inside the gas generator turbine. The rotor configuration results in eight degree of freedom (DOF) rotordynamic motions, which are two cylindrical modes and two conical modes from the two rotors. Stiffness of bump foils of candidate AFB was estimated from measured structural stiffness of the bearing, and implemented to the computational model for linear stiffness and damping coefficients of the bearing and frequency-domain modal impedances for cylindrical and conical modes. Stiffness of the diaphragm coupling was evaluated using finite element analysis and implemented to nonlinear rotordynamic analyses of the entire engine. Analyses show the conical mode of the turbine rotor is the main source of instability of the entire engine when AFB clearance is not selected properly. Optimum AFB clearance is suggested from frequency domain modal analyses and nonlinear transient analyses.
Effect of Bending and Mushrooming Damages on Heat Transfer Characteristic in Labyrinth Seals
Authors: Yan Xin , Lei Lijie , Li Jun , Feng Zhenping
Published: November 2013

Using conjugate heat transfer calculations, the heat transfer in straight-through labyrinth seals with and without rub damages (bending and mushrooming damages) were numerically investigated. Firstly, the numerical methods were carefully validated on the basis of obtained experimental data. At two different sealing clearances and a range of Reynolds numbers, Nu distributions on the seal rotor and stator surfaces for the original design cases were numerically computed and compared to the experimental data. The temperature fields in the fluid and inside the solid domains were obtained to account for the heat transfers between fluid and adjacent solids. Then, a range of bending angles, wear-off ratios, and mushrooming radiuses were selected to investigate the influence of rub damages on heat transfer characteristic in the labyrinth seals, and the numerical results were also compared to that of the original design cases. The results show that the calculated Nu distributions are in good agreement with the experimental data at a range of Re numbers and different sealing clearances. The turbulence model has a pronounced effect on the heat transfer computations for the labyrinth seal. Among the selected eddy viscosity turbulence models, the low-Re k-ω and SST turbulence models show superior accuracy to the standard k-ε and renormalization group (RNG) k-ε turbulence models, which overpredict Nu by about 70%. Bending damage reduces Nu on the labyrinth fin whereas it enhances heat transfer on the opposite smooth stator. The effect of bending angle on Nu distribution on the seal stator surface is larger than on the rotor surface. The mushrooming damage has a pronounced effect on Nu distributions on both rotor and stator surfaces for the labyrinth seal. It shows that Nu distributions on the rotor and stator surfaces decreases with the increase of the mushrooming radius, but increases with the increase of wear-off ratio and Re.
Influence of Coolant Density on Turbine Blade Film-Cooling With Axial and Compound Shaped Holes
Authors: Liu Kevin , Yang Shang-Feng , Han Je-Chin
Published: November 2013

Adiabatic film-cooling effectiveness is examined systematically on a typical high pressure turbine blade by varying three critical flow parameters: coolant blowing ratio, coolant-to-mainstream density ratio, and freestream turbulence intensity. Three coolant density ratios 1.0, 1.5, and 2.0 are chosen for this study. The average blowing ration and the turbulence intensity are 1.5% and 10.5%, respectively. Conduction-free pressure sensitive paint (PSP) technique is used to measure film-cooling effectiveness. Foreign gases are used to study the effect of coolant density. Two test blades feature axial angle and 45 deg compound-angle shaped holes on the suction side and pressure side. Both designs have 3 rows of 30 deg radial-angle cylindrical holes around the leading edge region. The inlet and the exit Mach number are 0.27 and 0.44, respectively. Reynolds number based on the exit velocity and blade axial chord length is 750,000. Overall, the compound angle design performs better film coverage that axial angle. Greater coolant-to-mainstream density ratio results in lower coolant-to-mainstream momentum and prevents coolant to lift-off.
Preliminary Articulable Probe Designs With RAVEN and Challenges: Image-Guided Robotic Surgery Multitool System
Authors: Jong Yoon W. , Velasquez Carlos A. , White Lee W. , Hannaford Blake , Sang Kim Yoon , Lendvay Thomas S.
Published: November 2013

The primary focus of the vision systems in current minimally invasive surgery (MIS) surgical systems has been on the improvement of immersive experience through a static approach. One of the current limitations in an MIS robotic surgery is the limited field of view and restricted perspective due to the use of a sole rigid 3D endoscope. We seek to integrate a modular articulable imaging device and the teleoperated surgical robot, RAVEN. Another additional flexible imager can be helpful in viewing occluded surgical targets, giving increased visualization options. Two probe designs are proposed and tested to evaluate a robotized steering mechanism within the MIS robot framework. Both designs, a separate flexible imager and a fixed camera on a tool tip, did not show much improvement in reducing task completion time. The new system may have some potential in improved precise manipulation of surgical tools, which may offer safety benefits once the surgeon is trained. We have demonstrated feasibility of a novel MIS instrument imaging device to aid in viewing potentially occluded surgical targets. A new concept, a modular axis-shared articulable imaging probe located at the vicinity of a tool tip, is proposed for future evaluation. Full integration of the new flexible imaging device into the grasper of the RAVEN surgical robot is under study coordinated with clinicians.
Effect of Profile Corners on the Nitriding Treatment of AISI H13 Hot Extrusion Dies
Authors: Akhtar Syed Sohail , Arif Abul Fazal M.
Published: November 2013

One of the utmost challenges of hot aluminum extrusion is to design the die cavities with sharp corners (used to extrude thin-walled profiles) by considering the effective nitriding surface treatment of the die bearing surface in terms of nitride layer uniformity. In the present study, various AISI H13 steel samples (having commonly used profile geometric features) are manufactured using wire electro-discharge machining (EDM) and subsequently nitrided using two-stage controlled nitriding treatment. As a special case, corner features are investigated in terms of compound and nitride layers formation using optical and scanning electron microscopes. Finite element (FE) code abaqus is used to simulate the nitriding process using mass diffusion analysis in line with experimental set up. Both experimental and numerical results are found in close agreement in terms of nitrogen concentration and corresponding microhardness profiles. Some design modifications are implemented in FE code for corner profile features for uniform nitride layer development. In view of the current results, some design guidelines are suggested for effective and uniform nitride layer formation in order to secure high quality extruded product and extended die life.
Comparison of Ball Pull Strength Among Various Sn-Cu-Ni Solder Joints With Different Pad Surface Finishes
Authors: Yang Chaoran , Song Fubin , Ricky Lee S. W.
Published: November 2013

SnCuNi is one of the most common ternary intermetallic compounds formed in the Sn-based solder joint, and its formation and properties can be greatly influenced by the amount of Ni. Ni can participate in the interfacial reaction and diffuse into the intermetallic compound layer from either the solder or from the pad. In this research, comparative studies of different SnCuNi intermetallic compounds were conducted using two kinds of SnCuNi solders with organic solderability preservatives pad finish and a SnCu solder with electroless nickel/immersion gold pad finish. In the former case, Ni can only diffuse into the intermetallic compound from the solder matrix, while in the latter the Ni is only from the metallization layer on the Cu base. Scanning electron microscopy and transmission electron microscopy were employed to inspect the morphologies and interfacial microstructures of the intermetallic compounds. The thermal aging test was conducted to investigate their growth behavior under elevated temperature conditions. Mechanical strength after different aging hours was also evaluated via high speed ball pull test.
Squealer Tip Leakage Flow Characteristics in Transonic Condition
Authors: Li Wei , Jiang Hongmei , Zhang Qiang , Woo Lee Sang
Published: November 2013

The over-tip-leakage (OTL) flow characteristics for a typical squealer tip of a high-pressure turbine blade, which consists of subsonic and transonic flow, have been numerically investigated in the present study, in comparison with the corresponding flat tip results. For the squealer tip employed, flow choking behavior still exists above the tip surface, even though the Mach number is lower and the transonic region is smaller than that for the flat tip. Detailed flow structure analysis shows that most of the fluid entering the squealer cavity is from the frontal leading edge region. The fluid migrates along the cavity and is ejected at various locations near the suction side rim. These fluids form a large subsonic flow zone under the supersonic flow passing over the tip gap which reduces the OTL flow flux. The squealer design works even in the presence of choked OTL flow. Comparisons between results from three different cavity depths with and without relative casing motion suggest that the over-tip-leakage flow flux has much dependence upon the cavity depth for the subsonic region, but is less sensitive to the depth for the transonic tip flow region. Such behavior has been confirmed with and without the existence of relative casing motion.
The Effect of Heat Transfer Area Roughness on Heat Transfer Enhancement by Forced Convection
Authors: Cernecky Jozef , Koniar Jan , Brodnianska Zuzana
Published: November 2013

The paper deals with the visualization of temperature fields in the vicinity of profiled heat transfer surfaces and a subsequent analysis of local values of Nusselt numbers by forced air convection in an experimental channel. Holographic interferometry was used for visualizing the temperature fields. Experiments were carried out at Re 462 up to 2338 at the distances between heat transfer surfaces of 0.025 m and 0.035 m. Temperature contours were determined from the obtained images of holographic interferograms of temperature fields and the local values of Nusselt numbers along the profiled surface for x/s = 0 up to x/s = 1.25 were calculated from them. A significant effect of the profiled surface on the local values of Nusselt numbers can be observed from the obtained results.
Long-Term SOFCs Button Cell Testing
Authors: DiGiuseppe Gianfranco , Sun Li
Published: November 2013

This paper reports a new study where relatively long-term tests of about a 1000 h are performed on several planar anode-supported solid oxide fuel cells. The cell electrochemical behaviors are studied by using voltage-current density measurement, electrochemical impedance spectroscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The cell total polarization obtained from electrochemical impedance spectroscopy results is shown to be consistent with the area-specific resistance calculated from the voltage-current density curve over the course of the test. In addition, a four-constant phase element model is used to analyze the cell components resistances at different intervals over the lifetime of the test. Scanning electron microscopy and energy-dispersive X-ray spectroscopy are used postmortem to determine if any damages occurred to the cells and to determine if any change in composition occurred to the lanthanum strontium cobalt ferrite cathode. This study shows that the tested cells remain stable with a relatively small increase in the cell total polarization but with no increase in ohmic resistance.
Quality assurance of asymmetric jaw alignment using 2D diode array
Authors: Kim Sun Mo , Chmielewski Renata , Abbas Ahmar , Yeung Ivan W. T. , Moseley Douglas J.
Published: November 2013

Purpose:

A method using a 2D diode array is proposed to measure the junction gap (or overlap) and dose with high precision for routine quality assurance of the asymmetric jaw alignment.

Methods:

The central axis (CAX) of the radiation field was determined with a 15 × 15 cm2 photon field at four cardinal collimator angles so that the junction gap (or overlap) can be measured with respect to the CAX. Two abutting fields having a field size of 15 cm (length along the axis parallel to the junction) × 7.5 cm (width along the axis perpendicular to the junction) were used to irradiate the 2D diode array (MapCHECK2) with 100 MU delivered at the photon energy of 6 MV. The collimator was slightly rotated at 15° with respect to the beam central axis to increase the number of diodes effective on the measurement of junction gap. The junction gap and dose measured in high spatial resolution were compared to the conventional methods using an electronic portal imaging device (EPID) and radiochromic film, respectively. In addition, the reproducibility and sensitivity of the proposed method to the measurements of junction gap and dose were investigated.

Results:

The junction gap (or overlap) and dose measured by MapCHECK2 agreed well to those measured by the conventional methods of EPID and film (the differences ranged from −0.01 to 0 cm and from −1.34% to 0.6% for the gap and dose, respectively). No variation in the repeat measurements of the junction gap was found whereas the measurements of junction dose were found to vary in quite a small range over the days of measurement (0.21%–0.35%). While the sensitivity of the measured junction gap to the actual junction gap applied was the ideal value of 1 cm/cm as expected, the sensitivity of the junction dose to the actual junction gap increased as the junction gap (or overlap) decreased (maximum sensitivity: 201.7%/cm).

Conclusions:

The initial results suggest that the method is applicable for a comprehensive quality assurance of the asymmetric jaw alignment.
Effects of phonetically-cued talker variation on semantic encoding
Authors: Sumner Meghan , Kataoka Reiko
Published: November 2013

This study reports equivalence in recognition for variable productions of spoken words that differ greatly in frequency. General American (GA) listeners participated in either a semantic priming or a false-memory task, each with three talkers with different accents: GA, New York City (NYC), and Southern Standard British English (BE). GA/BE induced strong semantic priming and low false recall rates. NYC induced no semantic priming but high false recall rates. These results challenge current theory and illuminate encoding-based differences sensitive to phonetically-cued talker variation. The findings highlight the central role of phonetic variation in the spoken word recognition process.
The Duration of T Cell Stimulation Is a Critical Determinant of Cell Fate and Plasticity
Authors: Miskov-Zivanov Natasa , Turner Michael S. , Kane Lawrence P. , Morel Penelope A. , Faeder James R.
Published: November 2013

The duration of T cell receptor contact with antigen modulates the pattern of downstream signaling to determine CD4
+
T cell fate.
Wiring the Retina
Authors: Hines Pamela J.
Published: November 2013

Work in mice reveals how motion-detection circuitry is established during visual system development.
Simple Colorimetric Trypanothione Reductase-Based Assay for High-Throughput Screening of Drugs against Leishmania Intracellular Amastigotes
Authors: van den Bogaart Erika , Schoone Gerard J. , England Paul , Faber Dorien , Orrling Kristina M. , Dujardin Jean-Claude , Sundar Shyam , Schallig Henk D. F. H. , Adams Emily R.
Published: November 2013

Critical to the search for new anti-leishmanial drugs is the availability of high-throughput screening (HTS) methods to test chemical compounds against the relevant stage for pathogenesis, the intracellular amastigotes. Recent progress in automated microscopy and genetic recombination has produced powerful tools for drug discovery. Nevertheless, a simple and efficient test for measuring drug activity against
Leishmania
clinical isolates is lacking. Here we describe a quantitative colorimetric assay in which the activity of a
Leishmania
native enzyme is used to assess parasite viability. Enzymatic reduction of disulfide trypanothione, monitored by a microtiter plate reader, was used to quantify the growth of
Leishmania
parasites. An excellent correlation was found between the optical density at 412 nm and the number of parasites inoculated. Pharmacological validation of the assay was performed against the conventional alamarBlue method for promastigotes and standard microscopy for intracellular amastigotes. The activity of a selected-compound panel, including several anti-leishmanial reference drugs, demonstrated high consistency between the newly developed assay and the reference method and corroborated previously published data. Quality assessment with standard measures confirmed the robustness and reproducibility of the assay, which performed in compliance with HTS requirements. This simple and rapid assay provides a reliable, accurate method for screening anti-leishmanial agents, with high throughput. The basic equipment and manipulation required to perform the assay make it easy to implement, simplifying the method for scoring inhibitor assays.
Derepressed Transfer Properties Leading to the Efficient Spread of the Plasmid Encoding Carbapenemase OXA-48
Authors: Potron Anaïs , Poirel Laurent , Nordmann Patrice
Published: November 2013

The current emergence of the carbapenemase OXA-48 among
Enterobacteriaceae
is related to the spread of a single IncL/M-type plasmid, pOXA-48a. This plasmid harbors the
bla
OXA-48
gene within a composite transposon, Tn
1999
, which is inserted into the
tir
gene, encoding a transfer inhibition protein. We showed that the insertion of Tn
1999
into the
tir
gene was involved in a higher transfer frequency of plasmid pOXA-48a. This may likely be the key factor for the successful dissemination of this plasmid.