bluuebunny/crossref_metadata_2025 huggingface dataset:
Empiric switch from calcineurin inhibitor to sirolimus‐based immunosuppression in pediatric heart transplantation recipients
Authors: Loar Robert W. , Driscoll David J. , Kushwaha Sudhir S. , Cramer Carl H. , O'Leary Patrick W. , Daly Richard C. , Mauriello Daniel A. , Johnson Jonathan N.
Published: October 2013

Sirolimus is used in heart transplant patients with CAV and CNI‐induced nephropathy. However, little is known regarding the tolerability, rejection rate, and effect on renal function when used empirically in children. We describe our experience with the empiric use of a sirolimus‐based immunosuppressive regimen in pediatric heart transplantation recipients. We reviewed records of patients in whom conversion was attempted to a CNI‐free sirolimus‐based regimen. Rejection episodes and measures of renal function were recorded. We attempted to convert 20 patients, of which 16 were successful. In total, six of 20 patients (30%) experienced adverse effects. Of the 16 converted, four patients converted to sirolimus due to CNI‐induced disease (three nephropathy, one CAV), while 12 patients (mean age 5.5 yr, range 0.1–21 yr; 33% female; 33% with a history of congenital heart disease) were empirically switched to sirolimus at a mean of 2.3 yr after transplant. Follow‐up was available for a mean of 2.5 yr after conversion (range 0.5–8.3 yr). The rate of rejection while taking CNIs was 0.18 rejection episodes per patient‐year (total of five episodes), compared with 0.03 rejection episodes per patient‐year (total of one episode) while on sirolimus. Renal function, in terms of GFR, significantly improved after sirolimus conversion at latest follow‐up (from 86 ± 37 mL/min to 130 ± 49 mL/min, p = 0.02). Here, we demonstrate the potential benefit of empiric use of sirolimus in pediatric heart transplant patients in a CNI‐free regimen. Larger and longer studies are needed to further clarify risks of rejection and adverse effect profiles.
VPS 45‐associated primary infantile myelofibrosis – Successful treatment with hematopoietic stem cell transplantation
Authors: Stepensky Polina , Simanovsky Natalia , Averbuch Diana , Gross Menachem , Yanir Asaf , Mevorach Dror , Elpeleg Orly , Weintraub Michael
Published: October 2013

PMF of infancy is a recently described autosomal recessive disorder presenting with severe bone marrow failure, accelerated neutrophil apoptosis, and significant platelet dysfunction, caused by a mutation in the VPS45 gene. In this study, we update our group of patients with PMF, highlighting different aspects of this disease, and evaluating the effectiveness of HSCT for the treatment of this disorder. Update of clinical data, hematological features, molecular studies, treatment and final outcome of four children diagnosed with VPS 45‐associated PMF of infancy. The patients described had clinical and hematological findings consistent with MF. Molecular studies showed that all patients were homozygous for the Thr224Asn mutation in the VPS 45 gene. HSCT was carried out in three patients and was successful in two. VPS 45‐associated MF is a novel primary immune deficiency that can be successfully corrected by HSCT if applied early in the course of disease using appropriate conditioning. The diagnosis of VPS 45‐associated PMF should be considered in all children presenting with SCN with subsequent development of pancytopenia. Long‐term follow‐up of these patients is necessary to identify extra‐hematological manifestations of VPS45 deficiency.
Comparative study of metal resistance and accumulation of lead and zinc in two poplars
Authors: Chen Lianghua , Gao Shun , Zhu Peng , Liu Yang , Hu Tingxing , Zhang Jian
Published: October 2013

In our study, we tested two poplars, Populus beijingensis and Populus cathayana, as model species for their potential for phytoremediation by measuring changes in biomass, pigments, superoxide radicals (O2−), cellular ultrastructure and their ability for O2− quenching and heavy metal accumulation when exposed to Pb, Zn and their interaction in a hydroponic system. Exposure to Pb did not cause a significant decrease in biomass in either P. beijingensis or P. cathayana. Correspondingly, no obvious impairment in cellular organelles was observed in either species, although the former species translocated a higher fraction of Pb to its shoots than the latter. In contrast, there were significant decreases in biomass and pigment content, and serious impairments in ultrastructure in both species when exposed to either Zn alone or to a combined treatment. Under such conditions, P. beijingensis showed smaller losses of biomass and pigments but a greater ability to quench O2− and maintained relatively intact cellular organelles compared with P. cathayana. Under the combined stress, there were no obvious additive effects on biomass, pigments or cellular impairment, whereas synergistic effects on metal absorption and accumulation in both species were observed when compared with exposure to either alone. Thus, the attribute of synergistic uptake and translocation in both species validates their potential to remediate soil contaminated by multiple metals. Moreover, our results indicated that P. beijingensis is a better potential candidate for phytoremediation than P. cathayana, due to its greater phytoremediation efficiency as well as its higher tolerance capacity.
Transcriptome profiling in response to different types of ionizing radiation and identification of multiple radio marker genes in rice
Authors: Hwang Jung Eun , Hwang Sun‐Goo , Kim Sun‐Hee , Lee Kyung Jun , Jang Cheol Seong , Kim Jin‐Baek , Kim Sang Hoon , Ha Bo‐Keun , Ahn Joon‐Woo , Kang Si‐Yong , Kim Dong Sub
Published: October 2013

Ionizing radiation (IR) affects gene expression from plant genomes. To monitor the genome‐wide transcriptional changes induced by three types of IR, we used the rice Affymetrix GeneChip microarray to identify genes that are up‐ or down‐regulated by gamma rays (GAs), cosmic rays (CRs) and ion beams (IBs). The overall expression patterns in rice seedlings generated from seeds exposed to GAs and IBs were similar but differed for CRs exposure. Expression profiles of genes involved in metabolic pathways and cellular response were identified using MapMan analysis. This result revealed that IRs induced gene expression related to sucrose–starch metabolisms; sugar and starch accumulation was significantly increased in response to three types of IR in rice. In addition, we compared the genes commonly up‐ or down‐regulated by exposure to three types of IR and identified 53 candidate radio marker genes (RMGs) that were differentially regulated by radiation exposure but not by other stresses. Among these genes, we selected six RMGs commonly applicable to different types of IR by specific coexpression networks using the algorithm for the reconstruction of accurate cellular networks (aracne) and confirmed the expression of these genes by reverse transcription‐polymerase chain reaction (RT‐PCR) analysis. Our results provided insight into the mechanisms of the responses to different types of IR and identified multiple marker genes to predict sensitivity to three types of IR.
Clinical utility of the Functional Independence Measure for assessment of patients with Alzheimer's disease and vascular dementia
Authors: Tanaka Naofumi , Nakatsuka Masahiro , Ishii Hiroshi , Nakayama Rie , Hosaka Ryoko , Meguro Kenichi
Published: October 2013

Aim

The aim of this study was to investigate the clinical utility of the Functional Independence Measure (FIM), and especially FIM‐Cognition (FIM‐C) scores, in patients with Alzheimer's disease (AD) and vascular dementia (VaD), and to determine the influence of behavioural and psychological symptoms of dementia (BPSD) on FIM‐C scores.

Methods

This was a cross‐sectional survey of 37 AD and 40 VaD patients. Cognitive function was assessed with the Cognitive Abilities Screening Instrument. Activities of daily living were evaluated with the FIM and the Barthel Index. BPSD were assessed with the Behavioural Pathology in Alzheimer's Disease Frequency Weighted Severity Scale.

Results

For both groups, Spearman's correlations were found between FIM‐Motor and Barthel Index scores and between FIM‐C and Mini Mental State Examination scores. Each FIM‐C subscore was correlated with Cognitive Abilities Screening Instrument scores in both groups, except for the FIM‐C Social interaction subscore in VaD. VaD patients showing Activity Disturbance and Aggressiveness on the Behavioural Pathology in Alzheimer's Disease Frequency Weighted Severity Scale had significantly lower FIM‐C Memory and Social interaction subscores than those without BPSD.

Conclusion

The results suggest that the FIM‐Motor and FIM‐C scales are useful measures of physical and cognitive disabilities in patients with AD and VaD. The FIM‐C profile of AD may reflect global cognitive function, while that of VaD may be more influenced by BPSD.
Stressful life events and neuroticism as predictors of late‐life versus early‐life depression
Authors: Weber Kerstin , Giannakopoulos Panteleimon , Herrmann François R. , Bartolomei Javier , DiGiorgio Sergio , Ortiz Chicherio Nadia , Delaloye Christophe , Ghisletta Paolo , Lecerf Thierry , De Ribaupierre Anik , Canuto Alessandra
Published: October 2013

Background:

The occurrence of depression in younger adults is related to the combination of long‐standing factors such as personality traits (neuroticism) and more acute factors such as the subjective impact of stressful life events. Whether an increase in physical illnesses changes these associations in old age depression remains a matter of debate.

Methods:

We compared 79 outpatients with major depression and 102 never‐depressed controls; subjects included both young (mean age: 35 years) and older (mean age: 70 years) adults. Assessments included the Social Readjustment Rating Scale, NEO Personality Inventory and Cumulative Illness Rating Scale. Logistic regression models analyzed the association between depression and subjective impact of stressful life events while controlling for neuroticism and physical illness.

Results:

Patients and controls experienced the same number of stressful life events in the past 12 months. However, in contrast to the controls, patients associated the events with a subjective negative emotional impact. Negative stress impact and levels of neuroticism, but not physical illness, significantly predicted depression in young age. In old age, negative stress impact was weakly associated with depression. In this age group, depressive illness was also determined by physical illness burden and neuroticism.

Conclusions:

Our data suggest that the subjective impact of life stressors, although rated as of the same magnitude, plays a less important role in accounting for depression in older age compared to young age. They also indicate an increasing weight of physical illness burden in the prediction of depression occurrence in old age.
Mental illness and a high‐risk, elderly Japanese population: characteristic differences related to gender and residential location
Authors: Kikuchi Hiroyuki , Takamiya Tomoko , Odagiri Yuko , Ohya Yumiko , Shimomitsu Teruichi , Inoue Shigeru
Published: October 2013

Purpose

Examining the sociodemographic determinants of psychological distress is important in identifying specific subgroups in need of further intervention. However, there are few studies focusing on older populations and on the role of gender or location of residence. To try to clarify characteristics of a population at high risk for mental illness, we examined the sociodemographic determinants of psychological distress in older adults living in three different locations.

Methods

A mail survey was used to collect data on levels of psychological distress and sociodemographic characteristics from a population‐based sample of 1894 older adults who lived in Bunkyo (urban setting), Fuchu (suburban setting) and Oyama (rural setting) in Japan (aged 65–74 years, 51.3% men). Psychological distress level was measured based on Kessler's six‐item psychological distress scale (K6) and dichotomized into two groups with a cut‐off score of 5 (0–4 or 5–24). Multiple logistic regression analyses were used to examine the associations between sociodemographic factors, specifically gender and location of residence, and psychological distress levels.

Results

The variables of older age, living in Bunkyo, living in Oyama and living alone were significantly associated with high psychological distress. Although these associations were observed in men, no associations were observed in women. Location‐specific analyses showed significant associations between sociodemographic and psychological distress among men living in Oyama, but not among those in Bunkyo or Fuchu.

Conclusions

Sociodemographic factors were significantly correlated with psychological distress, particularly among older men in rural areas. Characteristics of a population at high risk for mental illness may vary based on gender and location of residence. Health promotion initiatives for older adults may be more effective if they take these demographic factors into account.
Similar donors—similar blood?
Authors: Tarasev Michael , Alfano Kenneth , Chakraborty Sumita , Light Lucia , Doeden Kim , Gorlin Jed B.
Published: October 2013

Background

Red blood cell (RBC) storage lesions have been suggested as contributing factors to suboptimal clinical outcomes. While undesirable effects of storage are well documented, their clinical relevance is still debated. Focus on storage time as the sole determinant of RBC quality ignores the variability in cell properties that may depend on factors other than age. Mechanical fragility (MF) aggregately reflects many storage‐related functional and structural changes. This study evaluates interdonor versus intradonor variability, throughout storage, of both MF and autohemolysis (AH).

Study Design and Methods

Thirteen uniformly manufactured RBC units were collected initially as whole blood from nonsmoking, group A+, male Caucasian research donors. Mechanical stress was applied using a bead mill with oscillation at 50 Hz over durations varying from 0.5 to 60 minutes. MF profiles were described in terms of percent hemolysis after stresses of specified durations. Two months later, 11 of the 13 donors returned and assays were performed using the same protocol to allow comparison of intradonor versus interdonor variation.

Results

At 5 days postcollection, RBC MF profiles exhibited marked interdonor variability (up to twofold) overall. Both autolysis and MF across all units increased during storage—with rates of these increases varying by up to 10‐fold for certain MF variables. Especially high AH and MF were observed for an outlier donor (with p < 0.05), for whom follow‐up revealed previously undisclosed hereditary hypertriglyceridemia (levels exceeding approx. 1000 mg/dL).

Conclusions

RBCs, even from similar donors, vary significantly in levels and changes of both AH and MF, the clinical significance of which must still be ascertained. While further study is needed, donors with severe hypertriglyceridemia may not be appropriate as blood donors due to the unacceptable level of hemolysis observed during storage of our affected study subject.
Total nucleated cells as a sole predictor of distinct targets of hematopoietic potential (CD34+ cells) in cord blood units: the results of a large series analysis in autologous cord blood units
Authors: Mazzocchetti Daniele , Berti Amy Maria , Sartini Roberta , Lucarini Alessandra , Ragusa Giuseppe , Caroli Matteo , Pierelli Luca
Published: October 2013

Background

Rapid identification of eligible cord blood units (CBUs) for banking is an important issue in hematopoietic stem cell procurement. Distinct contents of CD34+ cells in CBU can contribute to identify grafts that may be banked also for unrelated transplants or limited to family‐directed or autologous use.

Study Design and Methods

Considering thresholds of CD34+ cell content of 3 × 106, 2 × 106, and 1 × 106 CD34+ cells, we analyzed a consecutive series of 1309 CBUs. CBUs were collected for autologous banking without any volume‐based preselection criteria. Predictors of distinct content of CD34+ cells have been assessed by receiver operating characteristic (ROC) curve analysis.

Results

Median total nucleated cell (TNC) and CD34+ cell counts of the series were 6.97 × 108 (range, 0.36 × 108‐34.9 × 108) and 1.47 × 106 (0‐20.56 × 106). Volumes ranged from 21 to 163 mL, with a median of 73.8 mL. For the CD34+ target of 1 × 106, the best predictor was TNC count with a threshold of 6.63 × 108; volume results were less predictive with a value of 68.1 mL. For CD34+ targets of 2 × 106 and 3 × 106, ROC curves confirmed a stronger predictive power of TNC, above the collected volume, with thresholds of 7.55 × 108 and 8.98 × 108. ROC analysis by combining all predictors (TNC, volume, TNC2, volume2, age of mothers, types of delivery, birthweight) gave worse results than TNC count alone.

Conclusions

This analysis, carried out on a large, unrestricted CBU series, shows that TNC alone is the best predictor of distinct targets of hematopoietic potential with the chance to predict CBU potentially useful for unrelated recipients or limited for family‐directed or autologous use.
An 8‐week course of 45 mg of carbonyl iron daily reduces iron deficiency in female whole blood donors aged 18 to 45 years: results of a prospective randomized controlled trial
Authors: Marks Denese C. , Speedy Joanna , Robinson Kathryn L. , Brama Tania , Capper Hugh R. , Mondy Phillip , Keller Anthony J.
Published: October 2013

Background

Blood donation is known to contribute to iron deficiency in regular blood donors. This study investigated the safety and efficacy of postdonation iron replacement to mitigate iron deficiency in blood donors.

Study Design and Methods

A total of 282 female whole blood donors aged 18 to 45 were prospectively randomized in a double‐blinded placebo controlled trial to receive an 8‐week postdonation course of carbonyl iron (45 mg daily) or placebo. The primary endpoint was prevalence of iron deficiency (ferritin < 15 ng/mL) at 12 weeks postdonation. Secondary endpoints were eligibility to donate based on capillary hemoglobin (Hb) and incidence of gastrointestinal (GI) complaints.

Results

Ferritin levels at Week 12 were significantly higher in donors receiving carbonyl iron (17.0 ± 10.9 ng/mL) compared with those receiving placebo (10.6 ± 8.4 ng/mL; p < 0.001). The proportion of iron‐deficient donors was significantly lower in the carbonyl iron group (51.9%) compared to the placebo (80.5%; p < 0.001). The mean Hb level in the carbonyl iron group (134.6 ± 8.7 g/L) was significantly higher than in the placebo arm (130.0 ± 9.9 g/L; p < 0.001), significantly improving eligibility to donate at Week 12. Significantly more donors receiving carbonyl iron had at least one GI side effect (p < 0.001). Importantly, 86.7% of donors receiving carbonyl iron indicated that they would take iron on an ongoing basis.

Conclusion

An 8‐week postdonation course of 45 mg of carbonyl iron significantly reduced iron deficiency and was well tolerated in female whole blood donors. Postdonation iron replacement may have a role in a broader strategy to optimize donor iron status.
Lamellar keratoplasty in rabbits using human and rabbit amniotic membrane grafts: a comparative study
Authors: Godoy‐Esteves Cintia A. L. , Gomes José Álvaro P. , Yazbek Karina , Guerra José L. , Barros Paulo S. M.
Published: October 2013

Objective

To compare the behavior of human and rabbit amniotic membrane (AM) grafts in surgically induced corneal thinning in rabbits.

Animals studied

Thirty two NZWR were randomly assigned to two groups of 16 animals each according to AM type (Human AM: group HAM and Rabbit AM: group RAM).

Procedure

All animals were submitted to right keratectomy at a depth of 0.1 mm using a 5 mm trephine. Animals from HAM group had a button of 5 mm of human AM sutured into the corneal bed with a continuous pattern and 10.0 nylon monofilament suture, while animals from the RAM group had a button of 6 mm diameter of rabbit AM. Four animals in each group were euthanized 2, 7, 15, and 30 days postoperatively. Their corneas were harvested, fixed in 2% glutaraldehyde solution, and stained with haematoxylin–eosin, picrosirius red, and alcian blue for evaluation under light optical microscopy. Microscope images were digitalized and inflammatory cells and stromal blood vessels were counted.

Results

There were no clinically significant differences between groups, and complete corneal epithelialization was observed in all animals in 30 days. Light optical microscopy revealed AM incorporation and resorption in both groups. However, the number of inflammatory cells and blood vessels was significantly higher in group HAM than in group RAM (P < 0.05, Mann–Whitney test). Clinical responses to human or rabbit AM were similar; however, human AM induced greater inflammatory reaction and stromal neovascularization in the rabbit cornea than in rabbit AM.

Conclusion

These differences may reflect a potential reaction to the xenograft. More studies are needed to further characterize these findings.
Acquired canaliculocele with intranasal extension in a dog
Authors: Durieux Philippe , Libermann Stéphane , Rattez Elise , Lagadic Marie , Ruel Yannick , Chen Thomas
Published: October 2013

To describe a case of a nasolacrimal canaliculocele with intranasal extension in a dog. A 6‐year‐old neutered femaleJackRussellTerrier was referred to theCentreHospitalierVétérinaire desCordeliers for a slowly enlarging mass adjacent to the medial canthus of the right eye of 5 months duration. Ophthalmic exam, ultrasound, fine needle aspiration, dacryocystorhinography and computerized tomography examinations were performed. Rhinoendoscopic treatment with marsupialisation of the endonasal canaliculocele was performed. Physical examination revealed a 3 cm diameter, subcutaneous mass beneath the medial canthus of the right eye, with a defect in the maxillary bone below. Dacryocystorhinography demonstrated blockage at the level of the nasolacrimal duct. Fine needle aspiration confirmed the cavitary nature of the lesion. During rhinoendoscopy, a mass containing watery fluid was found. Following marsupialisation with a large mass wall resection, the lacrimal drainage system irrigated freely in the nasal chamber. The communication of the lumen of the diverticulum with the lumen of the superior but not the inferior canaliculus was clearly demonstrated during endoscopy. Given negative immunohistochemical staining for smooth muscle actin and desmin, nasolacrimal dacryocele appears to be the most likely diagnosis. Histological examination confirmed that no goblet cells were present in the wall of the diverticulum, which is consistent with the canaliculus rather than the lacrimal sac. Complete resolution was observed without recurrence one year after surgery. Despite its rarity, a canaliculocele should be considered in adult dogs with nasolacrimal duct obstruction. Marsupialisation seems to be the appropriate therapy.
Paracrine anti‐fibrotic effects of neonatal cells and living cell constructs on young and senescent human dermal fibroblasts
Authors: Pratsinis Harris , Armatas Andreas , Dimozi Anastasia , Lefaki Maria , Vassiliu Pantelis , Kletsas Dimitris
Published: October 2013

Senescent cells observed in the area of chronic wounds have been proposed to affect wound healing. Therapeutic approaches against chronic wounds include, among others, the local application of living cell constructs (LCCs), containing fibroblasts and/or keratinocytes. Accordingly, the aim of the present work was to examine the effects of factors secreted by early passage neonatal fibroblasts and LCCs—in the form of a conditioned medium (CM)—on senescent adult dermal fibroblasts regarding functions related to the healing process, i.e., cell proliferation, alpha‐smooth muscle actin and metalloproteinase expression, and collagen synthesis. Target cells were fibroblasts senescent either due to subsequent divisions (replicative senescence) or due to an exogenous stress (stress‐induced premature senescence). No effect on the proliferation of senescent fibroblasts was observed, as expected. All CMs were found to inhibit overall collagen synthesis both in early passage and in senescent fibroblasts. The LCC‐derived CM was found to be more potent than fibroblast‐derived CMs and, furthermore, to inhibit alpha‐smooth muscle actin expression. In conclusion, these results may indicate anti‐contractile and anti‐fibrotic activities of factor(s) secreted by neonatal skin fibroblasts, and more intensely by LCCs on adult donor‐derived fibroblasts. These activities seem to persist during senescence of the target cells.
Frequency-Modulation Input Shaping Control of Double-Pendulum Overhead Cranes
Authors: Masoud Ziyad N. , Alhazza Khaled A.
Published: October 2013

Traditionally, multimode input shaping controllers are tuned to systems' frequencies. This work suggests an alternative approach. A frequency-modulation (FM) input shaping technique is developed to tune the resonant frequencies of a system to a set of frequencies that can be eliminated by a single-mode primary input shaper. Most of the current input shaping techniques can be used as primary input shapers for the FM input shaping technique. Virtual feedback is used to modulate the closed-loop frequencies of a simulated double-pendulum model of an overhead crane to the point where the closed-loop second mode frequency becomes an odd-multiple of the closed-loop first mode frequency, which is the necessary condition for a satisfactory performance of most single-mode input shapers. The primary input shaper is based on the first mode frequency of the closed-loop system model. The input commands to the plant of the virtual feedback system are then used to drive the physical double-pendulum. Simulations results, using primary zero-vibration (ZV) and zero-vibration-derivative (ZVD) input shapers, are presented. The performance is validated experimentally on a scaled model of a double-pendulum overhead crane.
A Guide to Design Disturbance Observer
Authors: Sariyildiz Emre , Ohnishi Kouhei
Published: October 2013

The goal of this paper is to clarify the robustness and performance constraints in the design of control systems based on disturbance observer (DOB). Although the bandwidth constraints of a DOB have long been very well-known by experiences and observations, they have not been formulated and clearly reported yet. In this regard, the Bode and Poisson integral formulas are utilized in the robustness analysis so that the bandwidth constraints of a DOB are derived analytically. In this paper, it is shown that the bandwidth of a DOB has upper and lower bounds to obtain a good robustness if the plant has nonminimum phase zero(s) and pole(s), respectively. Besides that the performance of a system can be improved by using a higher order disturbance observer (HODOB); however, the robustness may deteriorate, and the bandwidth constraints become more severe. New analysis and design methods, which provide good robustness and predefined performance criteria, are proposed for the DOB based robust control systems. The validity of the proposals is verified by simulation results.
Adaptive Estimation Using Multiagent Network Identifiers With Undirected and Directed Graph Topologies
Authors: Sadikhov Teymur , Demetriou Michael A. , Haddad Wassim M. , Yucelen Tansel
Published: October 2013

In this paper, we present an adaptive estimation framework predicated on multiagent network identifiers with undirected and directed graph topologies. Specifically, the system state and plant parameters are identified online using N agents implementing adaptive observers with an interagent communication architecture. The adaptive observer architecture includes an additive term which involves a penalty on the mismatch between the state and parameter estimates. The proposed architecture is shown to guarantee state and parameter estimate consensus. Furthermore, the proposed adaptive identifier architecture provides a measure of agreement of the state and parameter estimates that is independent of the network topology and guarantees that the deviation from the mean estimate for both the state and parameter estimates converge to zero. Finally, an illustrative numerical example is provided to demonstrate the efficacy of the proposed approach.
Experimental Study of High Temperature Hydrozing Annealing 1J50 Alloy's Magnetic Properties
Authors: Zhang Yingtao , Wang Gang , Nie Zhenguo , Shi Wankai , Rong Yiming
Published: October 2013

The good DC magnetic properties can be achieved for 1J50 soft magnetic alloy by applying high temperature hydrogen annealing. Annealing process parameters, e.g., atmosphere, soaking temperature, and time, are critical to soft magnetic properties. Qualitative results had been done for years. However a quantitative research among process parameters, microstructure, and magnetic properties can be more comprehensive and specific. In this study, a serial of experiments for 1J50 samples under the Chinese national standards. The influence of annealing temperature and socking time on DC magnetic properties and microstructure of the samples has been investigated on DC magnetic properties and microstructure of samples. The result shows that annealing process parameters have a nonlinear effect on the development of material microstructure and magnetic properties. Furthermore, the models among magnetic property, grain size, and process parameters have been built to quantitatively describe the interrelationship in between.
Spot Weld Layout Optimization of Tube Crash Performance With Manufacturing Constraints
Authors: Zhou Qing , Wu Xueyuan , Xia Yong , Cai Wayne
Published: October 2013

Spot weld layout is critical to structural performance of vehicle and its design is also subject to manufacturing constraints. In this study, using thin-walled tube crash as an example, we establish the relation between structural performance and weld layout design with manufacturing constraints from resistance spot welding. First, a straight tube crash performance is evaluated as a function of flange width, weld distance to flange corner, and weld pitch, without consideration of manufacturing constraints. All these parameters exhibit certain influence on the deformation mode and the energy absorption capacity. Then, an S-shaped tube is studied in the design optimization of weld layout by adding manufacturing constraints. The proposed approach can determine optimized results by simultaneously considering crash performance and manufacturing constraints. It is also concluded that weld layout has more significant influence on crash performance in straight tubes than in S-shaped tubes.
Modeling the Magnetic Performance of a Fast Pneumatic Brake Actuator
Authors: Miller Jonathan I. , Flack Tim J. , Cebon David
Published: October 2013

A novel pneumatic valve was constructed to improve the response of air-actuated brakes for heavy vehicles to demand pressures generated during electronically controlled braking by an order of magnitude. Investigations were made into the interactions between the magnetic, mechanical, and electrical subsystems of the valve with a view toward informing design optimization. The valve was modeled using a magnetic circuit approach. The quasi-static model included the influences of the permanent magnet, field-line fringing, saturation, and the coil. Mechanical forces outputted by the model matched physical measurements with an error smaller than 10%, and magnetic fluxes throughout the circuit were generally within 20% of those found from experiments based on Faraday's law of induction, Gaussmeter measurements, and FEA simulations. A magneto-mechanical simulation of the valve switching states was created using mechanical and electrical equations, and curve-fits to the outputs of the magnetic circuit model. The simulation produced time histories of the valve's armature position that matched experimental measurements and adequately predicted working pressures. The final model required an approximation to the influence of the coil based on experimental results. Consequently, further research is recommended into the influence of solenoid coils on fringing in magnetic circuits.
The Kinematics of 6R-2P Mining Drill Jumbo
Authors: Jiang Qimi , Ahmed S. N.
Published: October 2013

This work directly solves the inverse kinematics of the 6R-2P drill jumbo with 2 redundant DOFs at the displacement level using θ1 and θ5 as inputs to avoid solving a nonlinear system. An approach for computing the pose of the end-effector used to drill each hole on the mine face is also proposed.
Three-Dimensional Beam Theory for Flexible Multibody Dynamics
Authors: Bauchau Olivier A. , Han Shilei
Published: October 2013

In multibody systems, it is common practice to approximate flexible components as beams or shells. More often than not, classical beam theories, such as the Euler–Bernoulli beam theory, form the basis of the analytical development for beam dynamics. The advantage of this approach is that it leads to simple kinematic representations of the problem: the beam's section is assumed to remain plane and its displacement field is fully defined by three displacement and three rotation components. While such an approach is capable of accurately capturing the kinetic energy of the system, it cannot adequately represent the strain energy. For instance, it is well known from Saint-Venant's theory for torsion that the cross-section will warp under torque, leading to a three-dimensional deformation state that generates a complex stress state. To overcome this problem, sectional stiffnesses are computed based on sophisticated mechanics of material theories that evaluate the complete state of deformation. These sectional stiffnesses are then used within the framework of a Euler–Bernoulli beam theory based on far simpler kinematic assumptions. While this approach works well for simple cross-sections made of homogeneous material, inaccurate predictions may result for realistic configurations, such as thin-walled sections, or sections comprising anisotropic materials. This paper presents a different approach to the problem. Based on a finite element discretization of the cross-section, an exact solution of the theory of three-dimensional elasticity is developed. The only approximation is that inherent to the finite element discretization. The proposed approach is based on the Hamiltonian formalism and leads to an expansion of the solution in terms of extremity and central solutions, as expected from Saint-Venant's principle.
Natural Convection in a Vertical Slit Microchannel With Superhydrophobic Slip and Temperature Jump
Authors: Wang C. Y. , Ng Chiu-On
Published: October 2013

Recent developments in microscale heat exchangers have heightened the need for the understanding of fluid flow and heat transfer in a microchannel. In this study, we look into fully-developed buoyancy-driven flow in a vertical parallel-plate microchannel, which has one wall exhibiting superhydrophobic slip and temperature jump, and another wall being a normal no-slip surface. Analytical solutions are derived for free convection in the channel, where the heating is applied to either one of the two walls, and by either constant wall temperature or constant heat flux. We examine how the superhydrophobic slip and temperature jump may affect the volume flow rate and the Nusselt number under various heating conditions. There exists a critical value of the temperature jump coefficient, above which the flow rate will be larger by heating the no-slip surface than by heating the superhydrophobic surface, whether by constant wall temperature or by constant heat flux. The opposite is true when the temperature jump coefficient is below the critical value. Also, the temperature jump can have a negative effect on the flow rate when the heating is by constant temperature on the superhydrophobic side of the channel, but will have a positive effect when the heating is on the no-slip side of the channel.
Phase Diagrams of Instabilities in Compressed Film-Substrate Systems
Authors: Wang Qiming , Zhao Xuanhe
Published: October 2013

Subject to a compressive membrane stress, an elastic film bonded on a substrate can become unstable, forming wrinkles, creases or delaminated buckles. Further increasing the compressive stress can induce advanced modes of instabilities including period-doubles, folds, localized ridges, delamination, and coexistent instabilities. While various instabilities in film-substrate systems under compression have been analyzed separately, a systematic and quantitative understanding of these instabilities is still elusive. Here we present a joint experimental and theoretical study to systematically explore the instabilities in elastic film-substrate systems under uniaxial compression. We use the Maxwell stability criterion to analyze the occurrence and evolution of instabilities analogous to phase transitions in thermodynamic systems. We show that the moduli of the film and the substrate, the film-substrate adhesion strength, the film thickness, and the prestretch in the substrate determine various modes of instabilities. Defects in the film-substrate system can facilitate it to overcome energy barriers during occurrence and evolution of instabilities. We provide a set of phase diagrams to predict both initial and advanced modes of instabilities in compressed film-substrate systems. The phase diagrams can be used to guide the design of film-substrate systems to achieve desired modes of instabilities.
Sensitivity Analysis for the Resistance on the Performance of a Pressure Vessel for Water Hammer Protection
Authors: Wan Wuyi , Huang Wenrui , Li Cong
Published: October 2013

Pressure vessels can greatly protect a water supply pipeline system from water hammer damages. In order to improve the performance of a pressure vessel, a strainer is proposed to compensate the resistance of the connecting pipe. A numerical model and program is established for a pressure vessel with an independent compensation strainer based on the method of characteristics (MOC). Using the proposed model, the hydraulic transient processes are simulated for a pressure vessel with various strainer resistances, and the hydraulic pressure and volume fluctuations are obtained by the proposed model. The influences of resistance on the transient process are analyzed and an optimal approach is suggested to determine the suitable compensation strainer for the pressure vessel. A water hammer protection system is optimized based on the proposed method. The result shows that the compensation strainer can largely affect both positive and negative water hammer pressure. If a suitable strainer is selected based on the proposed approach, the transient surge and extreme pressure distribution will decrease. To some degree, it is simple and convenient to improve a pressure vessel by employing an additional compensation strainer in the pipeline system for water hammer protection.
Overall Effectiveness of a Blade Endwall With Jet Impingement and Film Cooling
Authors: Mensch Amy , Thole Karen A.
Published: October 2013

Ever-increasing thermal loads on gas turbine components require improved cooling schemes to extend component life. Engine designers often rely on multiple thermal protection techniques, including internal cooling and external film cooling. A conjugate heat transfer model for the endwall of a seven-blade cascade was developed to examine the impact of both convective cooling and solid conduction through the endwall. Appropriate parameters were scaled to ensure engine-relevant temperatures were reported. External film cooling and internal jet impingement cooling were tested separately and together for their combined effects. Experiments with only film cooling showed high effectiveness around film-cooling holes due to convective cooling within the holes. Internal impingement cooling provided more uniform effectiveness than film cooling, and impingement effectiveness improved markedly with increasing blowing ratio. Combining internal impingement and external film cooling produced overall effectiveness values as high as 0.4. A simplified, one-dimensional heat transfer analysis was used to develop a prediction of the combined overall effectiveness using results from impingement only and film cooling only cases. The analysis resulted in relatively good predictions, which served to reinforce the consistency of the experimental data.
Selective atomic layer deposition of zirconia on copper patterned silicon substrates using ethanol as oxygen source as well as copper reductant
Authors: Kannan Selvaraj Sathees , Parulekar Jaya , Takoudis Christos G.
Published: October 2013

The authors report a new chemical approach for the selective atomic layer deposition of ultrathin layers of zirconium oxide (ZrO2) on copper patterned silicon surfaces. Instead of using common atomic layer deposition (ALD) oxygen sources such as water, oxygen, or ozone, the authors use ethanol, which serves as oxygen source for the ALD on the silicon side and as effective reducing agent on the copper side, thereby selectively depositing ZrO2 film on the silicon surface of the substrate without any deposition on copper up to at least 70 ALD cycles. The resulting ZrO2 nanofilm is found to be an effective copper diffusion barrier at temperatures at least up to 700 °C.
Dose equations for tube current modulation in CT scanning and the interpretation of the associated CTDIvol
Authors: Dixon Robert L. , Boone John M.
Published: October 2013

Purpose:

The scanner‐reported CTDIvol for automatic tube current modulation (TCM) has a different physical meaning from the traditional CTDIvol at constant mA, resulting in the dichotomy “CTDIvol of the first and second kinds” for which a physical interpretation is sought in hopes of establishing some commonality between the two.

Methods:

Rigorous equations are derived to describe the accumulated dose distributions for TCM. A comparison with formulae for scanner‐reported CTDIvol clearly identifies the source of their differences. Graphical dose simulations are also provided for a variety of TCM tube current distributions (including constant mA), all having the same scanner‐reported CTDIvol.

Results:

These convolution equations and simulations show that the local dose at z depends only weakly on the local tube currenti(z) due to the strong influence of scatter from all other locations along z, and that the “local CTDIvol(z)” does not represent a local dose but rather only a relative i(z) ≡ mA(z). TCM is a shift‐variant technique to which the CTDI‐paradigm does not apply and its application to TCM leads to a CTDIvol of the second kind which lacks relevance.

Conclusions:

While the traditional CTDIvol at constant mA conveys useful information (the peak dose at the center of the scan length), CTDIvol of the second kind conveys no useful information about the associated TCM dose distribution it purportedly represents and its physical interpretation remains elusive. On the other hand, the total energy absorbed E (“integral dose”) as well as its surrogate DLP remain robust between variable i(z) TCM and constant current i0 techniques, both depending only on the total mAs = ⟨i⟩t0 = i0 t0 during the beam‐on time t0.
Time‐resolved dose distributions to moving targets during volumetric modulated arc therapy with and without dynamic MLC tracking
Authors: Ravkilde Thomas , Keall Paul J. , Grau Cai , Høyer Morten , Poulsen Per R.
Published: October 2013

Purpose:

The highly conformal doses delivered by volumetric modulated arc therapy (VMAT) may be compromised by intrafraction target motion. Although dynamic multileaf collimator (DMLC) tracking can mitigate the dosimetric impact of motion on the accumulated dose, residual errors still exist. The purpose of this study was to investigate the temporal evolution of dose errors throughout VMAT treatments delivered with and without DMLC tracking.

Methods:

Tracking experiments were performed on a linear accelerator connected to prototype DMLC tracking software. A three‐axis motion stage reproduced representative clinical trajectories of four lung tumors and four prostates. For each trajectory, two VMAT treatment plans (low and high modulation) were delivered with and without DMLC tracking as well as to a static phantom for reference. Dose distributions were measured continuously at 72 Hz using a dosimeter with biplanar diode arrays. During tracking, the MLC leaves were continuously refitted to the 3D target position measured by an electromagnetic transponder at 30 Hz. The dosimetric errors caused in the 32 motion experiments were quantified by a time‐resolved 3%/3 mmγ‐test. The erroneously exposed areas in treatment beamˈs eye view (BEV) caused by inadequate real‐time MLC adaptation were calculated and compared with the time‐resolved γ failure rates.

Results:

The transientγ failure rate was on average 16.8% without tracking and 5.3% with tracking. The γ failure rate correlated well with the erroneously exposed areas in BEV (mean of Pearson r = 0.83, p < 0.001). For the final accumulated doses, the mean γ failure rate was 17.9% without tracking and 1.0% with tracking. With tracking the transient dose errors tended to cancel out resulting in the low mean γ failure rate for the accumulated doses.

Conclusions:

Time‐resolved measurements allow pinpointing of transient errors in dose during VMAT delivery as well as monitoring of erroneous dose evolution in key target positions. The erroneously exposed area in BEV was shown to be a good indicator of errors in the dose distribution during treatment delivery.
The future of fish bioacoustics.
Authors: Popper Arthur N. , Fay Richard R.
Published: October 2013

In 1993 (Brain, Behav. Evol. 41, 14–38 (1993)] we evaluated changes in our knowledge of fish bioacoustics since our 1973 review and proposed ten issues that still needed to be answered. This presentation asks whether we have have made progress on these issues since 1993 and poses questions for future fish bioacoustics research. Many of the topics suggested in 1993, such as sound localization mechanism, the roles of the swim bladder’ and other peripheral structures in hearing, and the contributions of pressure and particle motion in hearing are still open. There are also “newer” questions not apparent in 1993, such as mechanisms of ultrasound detection and the effects of increased human-generated noise on fish. The usefulness of thinking of fish as “hearing specialists” and “hearing generalists” still needs to be assessed. Finally, an overriding question related to the significance of the diversity of fishes and diversity in ear structure, has not been resolved. Indeed, we still do not know whether the diversity found in the fish auditory periphery and CNS are convergent mechanisms to glean the same kind(s) of information about sound, or whether the variation reflects different uses of sound by different species.