bluuebunny/crossref_metadata_2025 huggingface dataset:
Detection of N-Glycolyl GM3 Ganglioside in Neuroectodermal Tumors by Immunohistochemistry: An Attractive Vaccine Target for Aggressive Pediatric Cancer
Authors: Scursoni Alejandra M. , Galluzzo Laura , Camarero Sandra , Lopez Jessica , Lubieniecki Fabiana , Sampor Claudia , Segatori Valeria I. , Gabri Mariano R. , Alonso Daniel F. , Chantada Guillermo , de Dávila María Teresa G.
Published: September 2011

The N-glycolylated ganglioside NeuGc-GM3 has been described in solid tumors such as breast carcinoma, nonsmall cell lung cancer, and melanoma, but is usually not detected in normal human cells. Our aim was to evaluate the presence of NeuGc-GM3 in pediatric neuroectodermal tumors by immunohistochemistry. Twenty-seven archival cases of neuroblastoma and Ewing sarcoma family of tumors (ESFT) were analyzed. Formalin-fixed, paraffin-embedded tumor samples were cut into 5 μm sections. The monoclonal antibody 14F7, a mouse IgG1 that specifically recognizes NeuGc-GM3, and a peroxidase-labeled polymer conjugated to secondary antibodies were used. Presence of NeuGc-GM3 was evident in 23 of 27 cases (85%), with an average of about 70% of positive tumors cells. Immunoreactivity was moderate to intense in most tumors, showing a diffuse cytoplasmic and membranous staining, although cases of ESFT demonstrated a fine granular cytoplasmic pattern. No significant differences were observed between neuroblastoma with and without NMYC oncogene amplification, suggesting that expression of NeuGc-GM3 is preserved in more aggressive cancers. Until now, the expression of N-glycolylated gangliosides in pediatric neuroectodermal tumors has not been investigated. The present study evidenced the expression of NeuGc-GM3 in a high proportion of neuroectodermal tumors, suggesting its potential utility as a specific target of immunotherapy.
Evaluation of Chromosomal Instability in Diabetic Rats Treated with Naringin
Authors: A. Bakheet Saleh , M. Attia Sabry
Published: September 2011

We used the bone marrow DNA strand breaks, micronucleus formations, spermatocyte chromosomal aberrations, and sperm characteristic assays to investigate the chromosomal instability in somatic and germinal cells of diabetic rats treated with multiple doses of naringin. The obtained results revealed that naringin was neither cytotoxic nor genotoxic for the rats at all tested doses. Moreover, naringin significantly reduced the diabetes-induced chromosomal instability in somatic and germinal cells in a dose-dependent manner. In addition, diabetes induced marked biochemical alterations characteristic of oxidative stress including enhanced lipid peroxidation, accumulation of oxidized glutathione, reduction in reduced glutathione, and accumulation of intracellular reactive oxygen species. Treatment with naringin ameliorated these biochemical markers dose-dependently. In conclusion, naringin confers an appealing protective effect against diabetes-induced chromosomal instability towards rat somatic and germinal cells which might be explained partially via diminishing thede novofree radical generation induced by hyperglycemia. Thus, naringin might be a good candidate to reduce genotoxic risk associated with hyperglycemia and may provide decreases in the development of secondary malignancy and abnormal reproductive outcomes risks, which seems especially important for diabetic patients.
Bacterial Magnetosome: A Novel Biogenetic Magnetic Targeted Drug Carrier with Potential Multifunctions
Authors: Sun Jianbo , Li Ying , Liang Xing-Jie , Wang Paul C.
Published: September 2011

Bacterial magnetosomes (BMs) synthesized by magnetotactic bacteria have recently drawn great interest due to their unique features. BMs are used experimentally as carriers for antibodies, enzymes, ligands, nucleic acids, and chemotherapeutic drugs. In addition to the common attractive properties of magnetic carriers, BMs also show superiority as targeting nanoscale drug carriers, which is hardly matched by artificial magnetic particles. We are presenting the potential applications of BMs as drug carriers by introducing the drug-loading methods and strategies and the recent research progress of BMs which has contributed to the application of BMs as drug carriers.
Diagnosis and Management of Pulmonary Arterial Hypertension
Authors: Houtchens Jeanne , Martin Douglas , Klinger James R.
Published: September 2011

Pulmonary arterial hypertension is a rare disease, which requires a high index of suspicion to diagnose when patients initially present. Initial symptoms can be nonspecific and include complaints such as fatigue and mild dyspnea. Once the disease is suspected, echocardiography is used to estimate the pulmonary arterial (PA) pressure and to exclude secondary causes of elevated PA pressures such as left heart disease. Right heart catheterization with vasodilator challenge is critical to the proper assessment of pulmonary hemodynamics and to determine whether patients are likely to benefit from vasodilator therapy. Pathologically, the disease is characterized by deleterious remodeling of the distal pulmonary arterial and arteriolar circulation, which results in increased pulmonary vascular resistance. In the last fifteen years, medications from three different classes have been approved for the treatment of pulmonary arterial hypertension. These include the prostanoids, endothelin receptor antagonists, and phosphodiesterase-5 inhibitors.
Thermal Effect on Structure of Silver in Ion-Exchanged Soda-Lime Glasses and Aluminum-Doped Zinc Oxide Films
Authors: Wang Paul W. , Jiang Yanfeng , Hsu Jin-Cherng , Chen Yu-Yun , Lin Yung-Hsing , Chen Huang-Lu
Published: September 2011

Heat treatment is commonly used during device processing in order to achieve specific functionalities of the devices. How a series of heat treatment applies to accomplish this goal can be found in the literature. However, specific properties of the devices after the treatment are more emphasized than the details of the structural modifications in the industrial applications. In this paper, it is intended to illustrate the fundamental changes in the structure due to heat treatment which result in the desired physical properties of the devices. Two study cases, Ag ion-exchanged soda-lime glasses and aluminum doped ZnO (AZO) films, were illustrated. The changes in chemical states, the structural modification during and after heat treatment are explored. By understanding how the metallic Ag formed and accumulated during annealing, an optimum heat treatment to grow the proper size and density of silver quantum dots in the films are possible. Post annealing effect on the AZO films shows that the crystallinity, the peak positions shifts, and grain sizes were changed after annealing. Both illustrated cases indicate thermally induced changes in chemical state, the stress release, and rearrangement of atoms in materials during and after annealing.
Raman Amplifier Based on Amorphous Silicon Nanoparticles
Authors: Ferrara M. A. , Rendina I. , Basu S. N. , Dal Negro L. , Sirleto L.
Published: September 2011

The observation of stimulated Raman scattering in amorphous silicon nanoparticles embedded in Si-rich nitride/silicon superlattice structures (SRN/Si-SLs) is reported. Using a 1427 nm continuous-wavelength pump laser, an amplification of Stokes signal up to 0.9 dB/cm at 1540.6 nm and a significant reduction in threshold power of about 40% with respect to silicon are experimentally demonstrated. Our results indicate that amorphous silicon nanoparticles are a great promise for Si-based Raman lasers.
Nanodiamond Films for Applications in Electrochemical Systems
Authors: Azevedo A. F. , Baldan M. R. , Ferreira N. G.
Published: September 2011

The purpose of the present paper is to give an overview on the current development status of nanocrystalline diamond electrodes for electrochemical applications. Firstly, we describe a brief comparison between the general properties of nanocrystalline diamond (undoped and boron-doped) and boron-doped microcrystalline diamond films. This is followed by a summary of the nanodiamond preparation methods. Finally, we present a discussion about the undoped and boron-doped nanocrystalline diamond and their characteristics, electrochemical properties, and practical applications.
Evidence of Competition Between Two Canopy Ant Species: Is Aggressive Behavior Innate or Shaped by a Competitive Environment?
Authors: do Espírito Santo Nádia Barbosa , Ribeiro Sérvio Pontes , Santos Lopes Juliane Floriano
Published: September 2011

Competition occurs in all ecological communities, although it has not always been experimentally tested as a structuring force in the distribution of species. We tested the hypothesis that the aggressiveness exhibited byCamponotus rufipeschanges according to the pressures of a competitive environment. This is a dominant species in the montane forest of the Itacolomi State Park, Brazil, whereCamponotus sericeiventrisdoes not occur. Using bait traps in a field site where both species occur, (“Juiz de Fora” site) we showed thatC. sericeiventriswas able to removeC. rufipesworkers at the same bait. In the laboratory, we used dyadic encounters to test workers from both species taken from colonies found in areas where both occur and where onlyC. rufipeswas found.Camponotus rufipesfrom Itacolomi fought significantly less and was killed during the first few minutes in 60% of the events. On the other hand, the workers that co-existed withC. sericeiventrisin the field were more aggressive, but less efficient fighters than the latter. This investigation demonstrated existence of competition betweenC. rufipesandC. sericeiventris, and also the lower aggressiveness ofC. rufipes'individuals that did not co-exist in the field withC. sericeiventris.
PBC: Animal Models of Cholangiopathies and Possible Endogenous Viral Infections
Authors: Ninomiya Masashi , Ueno Yoshiyuki , Shimosegawa Tooru
Published: September 2011

Primary Biliary Cirrhosis (PBC) is considered an autoimmune disease characterized by immune-mediated destruction of the intrahepatic bile ducts and its characteristic serologic marker, the anti-mitochondrial antibody (AMA). Several factors were proposed to clarify the pathological and immunological mechanisms of PBC. Immunological reaction with a bacterial or a viral association was identified in the previous report, and it seems probable that PBC was thought to have such an etiology. The majority of patients with PBC was reported to have both RT-PCR and immunohistochemistry evidence of human betaretrovirus infection in lymph nodes or in 2008, the patient who developed PBC with high HIV viral load had an antiviral therapy and recovered. To understand the etiology of PBC associated with infection, several factors should be considered and especially animal models may be useful. In this paper, we introduce three typical animal models of PBC: the dominant-negative form of transforming growth factor-βreceptor type II (dnTGFβRII) mouse, IL-2Rα−/−mouse and NOD.c3c4 mouse, are enumerated and described, and we discuss previous reports of viral infection associated with PBC and consider the etiology of PBC from our analysis of results in NOD.c3c4 mouse.
RetargetingClostridium difficileToxin B to Neuronal Cells as a Potential Vehicle for Cytosolic Delivery of Therapeutic Biomolecules to Treat Botulism
Authors: Krautz-Peterson Greice , Zhang Yongrong , Chen Kevin , Oyler George A. , Feng Hanping , Shoemaker Charles B.
Published: September 2011

Botulinum neurotoxins (BoNTs) deliver a protease to neurons which can cause a flaccid paralysis called botulism. Development of botulism antidotes will require neuronal delivery of agents that inhibit or destroy the BoNT protease. Here, we investigated the potential of engineeringClostridium difficiletoxin B (TcdB) as a neuronal delivery vehicle by testing two recombinant TcdB chimeras. For AGT-TcdB chimera, an alkyltransferase (AGT) was appended to the N-terminal glucosyltransferase (GT) of TcdB. Recombinant AGT-TcdB had alkyltransferase activity, and the chimera was nearly as toxic to Vero cells as wild-type TcdB, suggesting efficient cytosolic delivery of the AGT/GT fusion. For AGT-TcdB-BoNT/A-Hc, the receptor-binding domain (RBD) of TcdB was replaced by the equivalent RBD from BoNT/A (BoNT/A-Hc). AGT-TcdB-BoNT/A-Hc was >25-fold more toxic to neuronal cells and >25-fold less toxic to Vero cells than AGT-TcdB. Thus, TcdB can be engineered for cytosolic delivery of biomolecules and improved targeting of neuronal cells.
The Association of Chronic Kidney Disease and Metabolic Syndrome with Incident Cardiovascular Events: Multiethnic Study of Atherosclerosis
Authors: Agarwal Subhashish , Shlipak Michael G. , Kramer Holly , Jain Aditya , Herrington David M.
Published: September 2011

Background. There is an association between chronic kidney disease (CKD) and metabolic syndrome (MetS). We examined the joint association of CKD and MetS with incident cardiovascular (CVD) events in the Multiethnic Study of Atherosclerosis (MESA) cohort.Methods. We analyzed 2,283 Caucasians, 363 Chinese, 1,449 African-Americans, and 1,068 Hispanics in the MESA cohort. CKD was defined by cystatin C estimated glomerular filtration rate ≤ 60 mL/min/1.73 m2and MetS was defined by NCEP criteria. Cox proportional regression adjusting for age, ethnicity, gender, study site, education, income, smoking, alcohol use, physical activity, and total and LDL cholesterol was performed to assess the joint association of CKD and MetS with incident CVD events. Participants were divided into four groups by presence of CKD and/or MetS and compared to the group without CKD and MetS (CKD−/MetS−). Tests for additive and multiplicative interactions between CKD and MetS and prediction of incident CVD were performed.Results. During follow-up period of 5.5 years, 283 participants developed CVD. Multivariate Cox regression analysis demonstrated that CKD and MetS were independent predictors of CVD (hazard ratio, 2.02 for CKD, and 2.55 for MetS). When participants were compared to the CKD−/MetS−group, adjusted HR for the CKD+/MetS+group was 5.56 (95% CI 3.72–8.12). There was no multiplicative interaction between CKD and MetS (P=0.2); however, there was presence of additive interaction. The relative excess risk for additive interaction (RERI) was 2.73,P=0.2, and the attributable portion (AP) was 0.49 (0.24–0.74).Conclusion. Our findings illustrate that the combination of CKD and MetS is a strong predictor of incident clinical cardiovascular events due to presence of additive interaction between CKD and MetS.
Lipofuscin Hypothesis of Alzheimer’s Disease
Authors: Giaccone Giorgio , Orsi Laura , Cupidi Chiara , Tagliavini Fabrizio
Published: September 2011

The primary culprit responsible for Alzheimer’s disease (AD) remains unknown. Aβ protein has been identified as the main component of amyloid of senile plaques, the hallmark lesion of AD, but it is not definitively established whether the formation of extracellular Aβ deposits is the absolute harbinger of the series of pathological events that hit the brain in the course of sporadic AD. The aim of this paper is to draw attention to a relatively overlooked age-related product, lipofuscin, and advance the hypothesis that its release into the extracellular space following the death of neurons may substantially contribute to the formation of senile plaques. The presence of intraneuronal Aβ, similarities between AD and age-related macular degeneration, and the possible explanation of some of the unknown issues in AD suggest that this hypothesis should not be discarded out of hand.
Use of an Implantable Monitor to Detect Arrhythmia Recurrences and Select Patients for Early Repeat Catheter Ablation for Atrial Fibrillation
Authors: Pokushalov Evgeny , Romanov Alexander , Corbucci Giorgio , Artyomenko Sergey , Turov Alex , Shirokova Natalya , Karaskov Alexander
Published: September 2011

Background—

Catheter ablation of atrial fibrillation (AF) has proved effective in curing highly symptomatic patients with paroxysmal AF. The aim of this prospective, randomized study was to identify the optimal treatment of patients with AF recurrences after the first ablation.

Methods and Results—

Two hundred eighty-six patients with paroxysmal AF underwent ablation (circumferential pulmonary vein isolation with linear lesions) and were monitored with an implantable cardiac monitor (Reveal XT, Medtronic). Patients without AF recurrences during the 3-month postablation period were assigned to group 1; those with AF recurrences to group 2. Patients in group 2 were randomly assigned to group 3 or group 4. Group 3 patients were treated only with antiarrhythmic drugs for 6 weeks, with no early reablation during the 3-month postablation period. In the case of AF recurrence after the 3-month postablation period, patients underwent reablation. Group 4 patients were treated according to the onset mechanism of AF recurrences, as detected and stored by the implantable cardiac monitor: antiarrhythmic drug therapy, but no reablation if AF was not preceded by triggers; early reablation if premature atrial beats or atrial tachycardias or flutter triggered AF. All patients were followed up for 1 year to assess maintenance of sinus rhythm in each group. On 12-month follow-up examination, of the 119 (42%) patients in group 1, 112 (94%) had no AF recurrences. Among the 83 patients in group 3, only 27 (33%) had no recurrences. Of the 84 group 4 patients, 67 (80%) had no AF recurrences (
P
<0.0001 versus group 3).

Conclusions—

Patients with recurrences after the first AF ablation are likely to respond to a second early ablation when AF is triggered by supraventricular arrhythmias or premature contractions.

Clinical Trial Registration—

URL:
http://www.clinicaltrials.gov
. Unique identifier: NCT01164319.
Bright-Blood T
2
-Weighted MRI Has High Diagnostic Accuracy for Myocardial Hemorrhage in Myocardial Infarction
Authors: Payne Alexander R. , Berry Colin , Kellman Peter , Anderson Rachel , Hsu Li-Yueh , Chen Marcus Y. , McPhaden Allan R. , Watkins Stuart , Schenke William , Wright Victor , Lederman Robert J. , Aletras Anthony H. , Arai Andrew E.
Published: September 2011

Background—

Myocardial hemorrhage after myocardial infarction (MI) usually goes undetected. We investigated the diagnostic accuracy of bright-blood T
2
-weighted cardiac MRI for myocardial hemorrhage in experimental MI.

Methods and Results—

MI was created in swine by occluding the left anterior descending (n=10) or circumflex (n=5) coronary arteries for 90 minutes followed by reperfusion for ≤3 days (n=2), 10 days (n=7), or 60 days (n=6). MRI was performed at 1.5 T, using bright-blood T
2
-prepared steady-state free-precession, T
2
* and early (1 minute) and late (10–15 minutes) gadolinium enhancement (EGE, LGE, respectively) MRI. Left ventricular sections and histology were assessed for hemorrhage by an experienced cardiac pathologist blinded to the MRI data. Hypointense regions on T
2
-weighted and contrast-enhanced MRI were independently determined by 3 cardiologists experienced in MRI who were also blinded to the pathology results. Eighty ventricular pathological sections were matched with MRI (n=68 for EGE MRI). All sections with evidence of MI (n=63, 79%) also exhibited hyperintense zones consistent with edema on T
2
-weighted MRI and infarct on LGE MRI. Myocardial hemorrhage occurred in 49 left ventricular sections (61%) and corresponded with signal voids on 48 T
2
-weighted (98%) and 26 LGE-MRI (53%). Alternatively, signal voids occurred in the absence of hemorrhage in 3 T
2
-weighted (90% specificity) and 5 LGE MRI (84% specificity). On EGE MRI, 27 of 43 cases of early microvascular obstruction corresponded with hemorrhage (63% sensitivity), whereas 5 of 25 defects occurred in the absence of hemorrhage (80% specificity). The positive and negative predictive values for pathological evidence of hemorrhage were 94% and 96% for T
2
-weighted, 84% and 55% for LGE MRI, and 85% and 56% for EGE MRI.

Conclusions—

Bright-blood T
2
-weighted MRI has high diagnostic accuracy for myocardial hemorrhage.
Extratropical Forcing of Tropical Atlantic Variability during Boreal Summer and Fall
Authors: Smirnov Dimitry , Vimont Daniel J.
Published: September 2011

The connection between midlatitude Atlantic sea surface temperature (SST) anomalies and tropical SST variations during boreal summer and fall are investigated using a coupled general circulation model (GCM). This research follows on an observational study that finds that, using linear inverse modeling (LIM), predictions of boreal summer tropical Atlantic Meridional Mode (AMM) variations can be made with skill exceeding persistence with lead times of about one year. The LIM framework identified extratropical Atlantic SST anomalies as important precursors to the AMM variations.

The authors have corroborated this finding using a general circulation model coupled to a slab ocean, which represents a completely different physical basis from the LIM. Initializing the GCM with the LIM-derived “optimal” SST anomaly in November results in a steady equatorward propagation of SST anomalies into the subtropics during the following boreal spring. Thereafter, the GCM suggests that two possible feedbacks propagate the SST anomalies farther equatorward and westward with minimal loss of amplitude: the dominant wind–evaporation–SST (WES) thermodynamic feedback and a secondary low-cloud–SST radiative feedback. This study shows that this result has strong seasonal dependence and consists of nonlinear interactions when considering warm and cold “optimal” conditions separately. One main finding is that oceanic dynamics are not essential to understanding extratropical–tropical interaction in the Atlantic basin. The authors also discuss the results of the study in context with previous studies investigating the extratropical forcing of tropical air–sea variability.
Applications of a Velocity Dealiasing Scheme to Data from the China New Generation Weather Radar System (CINRAD)
Authors: He Guangxin , Li Gang , Zou Xiaolei , Ray Peter Sawin
Published: September 2011

An improved velocity dealiasing algorithm is developed as an extension of the Next Generation Weather Radar (NEXRAD) dealiasing algorithm. The algorithm described in this paper is evaluated on selected China Next Generation Weather Radar (CINRAD) S-band radar radial velocity observations. This algorithm includes four modules for removing weak signals and determining the starting radial as a prelude to identifying and correcting aliased velocities. The proposed dealiasing algorithm was tested on 14 different weather systems, composed of typhoons, squall lines, and heavy rains. The results show that the algorithm is robust and stable for dealiasing S-band CINRAD radial velocity measurements. The performance levels for the typhoon and heavy rain cases are slightly better than for squall-line cases.
Shooting War Or Peace Photographs? An Examination of Newswires’ Coverage of the Conflict in Gaza (2008-2009)
Authors: Fahmy Shahira , Neumann Rico
Published: September 2011

According to Galtung, a peace journalism frame is one that highlights peace initiatives and tones down differences by promoting conflict resolution. A war journalism frame, in his view, is one that highlights differences between opposing parties, urging violence as means to a resolution. Thus, based on the above classification of these two competing frames of war coverage, this is one of the first studies to empirically test the model via a visual quantitative analysis. Using news photographs, this study analyzes the extent to which the Gaza War (2008-2009) was represented as war versus peace journalism in the three leading Western newswires (Associated Press, Reuters, and AFP/Getty Images). Findings indicate that all three wires combined provided a variety of visual frames to communicate a comprehensive coverage of the event. This observed pattern therefore highlights the role of gatekeeping in providing a broad-based understanding of conflicts. In other words, it becomes crucial to note that photo selections in terms of war versus peace journalism ultimately has an impact in shaping public opinion and influencing perceptions of news events. Furthermore, from a theoretical standpoint, this work expands the classification of war versus peace journalism by operationalizing these frames into concrete pictorial patterns from a visual communication perspective.
Influence of supramolecular additives on foam morphology of injection-molded i-PP
Authors: Stumpf Marieluise , Spörrer Andreas , Schmidt Hans-Werner , Altstädt Volker
Published: September 2011

Foaming isotactic polypropylene (i-PP) by foam injection molding usually results in inhomogeneous, large cell structures. Possibilities to realize more homogeneous and finer foam morphologies are adjusting processing parameters or adding nucleating agents. Often, inorganic nucleating agents such as talc in concentrations of about 2 wt% are used to influence the foam morphology. This article discusses the use of two benzene trisamide-based nucleating agents to control cell nucleation during foaming of i-PP. These additives form supramolecular nanostructures in the polymer melt acting first as nucleating sites for foam formation and second as nuclei for the polymer crystallization. Foaming was performed by foam injection molding with nitrogen as physical blowing agent. A specially designed variotherm mold technology was utilized to exactly control the foaming temperature, foaming pressure, and expansion ratio. Foamed i-PP samples were prepared with a density reduction of 50% and analyzed with respect to foam structure and mechanical properties. We demonstrate that the benzene trisamide additives have a strong influence on the foam morphology at very low additive concentrations. Only 0.02 wt% of an additive is sufficient to obtain a remarkable reduction of the cell sizes. It appears that the cell struts, those dimensions can be influenced by the additives as well, leads to a significant improvement of the mechanical properties.
Polyurethane flexible foam fire resisting by melamine and expandable graphite: Industrial approach
Authors: Gharehbaghi A , Bashirzadeh R , Ahmadi Z
Published: September 2011

According to importance of the safety issues especially in air industry, fire-resisted parts and interiors consumption are increasing. Seat foam has a huge fraction of the airplane interior and this makes it essential to become safer. From another point, planning to phase out some of the halogenated flame retardants because of persistence in the environment, bioaccumulation, and toxicity. In recent years, halogen-free fire retardants have been more investigated. In this work, we have concentrated more on two well-known, solid, halogen-free fire retardants, expandable graphite and melamine, and compared their performance according to their fire behavior, physical properties, and production phenomena.
Interactive parameter estimation for output error moving average systems
Authors: Xie Li , Yang Huizhong
Published: September 2011

In this paper we study parameter estimation problems for the output error moving average systems. In order to reduce calculation loads of the existing identification methods, an interactive stochastic gradient (ISG) algorithm is presented to estimate the parameters of the system model and the noise model, respectively, based on the interactive estimation theory. Since the ISG algorithm possesses a slow convergence rate and poor estimation accuracy, interactive gradient-based and interactive least-squares-based iterative algorithms are derived to enhance the parameter estimation performances of the ISG algorithm. The simulation results illustrate the effectiveness of the proposed algorithms.
Adaptive speed control of a PMSM servo system using an RBFN disturbance observer
Authors: Li Juan , Li Shihua , Chen Xisong
Published: September 2011

In order to improve the disturbance rejection property of Permanent-Magnet Synchronous Motor servo systems, a novel adaptive composite control method for the speed regulation problem is proposed in this paper. The composite controller is composed of a proportional feedback controller and a feedforward compensation based on a Radial Basis Function Network Disturbance Observer (P+RBFNDOB). The RBFNDOB is designed to estimate the lumped disturbances, including external disturbances and internal disturbances caused by parameter variations, and the estimation value is used for feedforward compensation design. Different from traditional Linear DOB (LDOB), an RBFN is used to approximate the inverse model of the system instead of selecting the inverse of the nominal model as in LDOB. By using an on-line learning algorithm, the identified inverse model can track the variations of the real plant. Thus, the RBFNDOB can still observe the disturbances when the parameters of the system vary in a wide range, while conventional DOB may not be suitable in such situations. So the composite controller obtained is inherently robust against parameter variations and external disturbances. A nearest neighbour clustering algorithm combining crude regulation and fine regulation is introduced as the on-line learning method to simplify the network structure and accelerate the learning speed. Rigorous analysis is also given to show why the RBFNDOB can effectively suppress the lumped disturbances of a closed-loop system. Simulation comparisons with two other methods, the composite control method with proportional feedback plus feedforward compensation based on LDOB (P+LDOB) and the conventional PI control method, verify the effectiveness of the proposed method.
Research on the application of Edlén’s formulation in compensation for ultra-precision motion platform’s measurement using an interferometer
Authors: Gao Zhenyu , Hu Jinchun , Zhu Yu , Duan Guanghong , Zhang Ming
Published: September 2011

The measurement accuracy of an interferometer is largely affected by the refractive index of air. Compared with the direct compensation method, the indirect compensation method is more suitable for compensation for an ultra-precision motion platform using an interferometer. However, the indirect compensation method depends on the air refractive index’s formula, which is empirical and not entirely accurate. It seems that the application of the indirect compensation method in a high-precision measured object is hampered. Considering that the repeat positioning accuracy of some application objects such as lithography’s ultra-precision platform is the highest requirement while the positioning accuracy is less demanding, this means that repeat measuring accuracy is the main factor. For these objects, this paper proposed a hypothesis of Birch and Downs’s revised Edlén’s formula firstly and derived the relation between the repeat measuring accuracy and the repeatability of environmental parameters on this basis when an indirect compensation method was used. An example on the analysis of the difference between Bonsch and Potulski’s further revised formula and Birch and Downs’s revised Edlén’s formula explains the rationality of the hypothesis. In addition, a simulation result on the lithography mask stage’s flow field showed that the indirect compensation method can achieve sub-nanometer repeat measuring accuracy and it meets repeat positioning accuracy’s requirement in lithography.
Miniaturized extracorporeal circulation vs. off-pump coronary artery bypass grafting: What the evidence shows?
Authors: Harling L , Punjabi P P , Athanasiou T
Published: September 2011

Recognition of the potentially deleterious effects of esxtracorporeal circulation led to off-pump coronary artery surgery (OPCAB) experiencing a surge in popularity in the initial decade after its conception. However, OPCAB has its own limitations and technical difficulties, such as coronary access, increased left ventricular size and reduced function, which may lead to the potential for suboptimal revascularization. As an alternative technique, miniaturized extracorporeal circulation (mECC) may provide a more controlled operative field in which the heart may be manipulated whilst minimizing the inflammatory, coagulopathic and haemodilutional effects of cardiopulmonary bypass. In this review, we outline the proposed benefits of the mECC system, discuss the pitfalls associated with mECC, and directly compare mECC to ‘off-pump’ coronary surgery for a variety of clinical and non-clinical outcomes.
Benefits of pulsatile flow in pediatric cardiopulmonary bypass procedures: from conception to conduction
Authors: Ündar A , Palanzo D , Qiu F , Alkan-Bozkaya T , Akcevin A , Talor J , Baer L , Woitas K , Wise R , McCoach R , Guan Y , Haines N , Wang S , Clark J B , Myers J L
Published: September 2011

This review on the benefits of pulsatile flow includes not only experimental and clinical data, but also attempts to further illuminate the major factors as to why this debate has continued during the past 55 years. Every single component of the cardiopulmonary bypass (CPB) circuitry is equally important for generating adequate quality of pulsatility, not only the pump. Therefore, translational research is a necessity to select the best components for the circuit. Generation of pulsatile flow depends on an energy gradient; precise quantification in terms of hemodynamic energy levels is, therefore, a necessity, not an option. Comparisons between perfusion modes should be done after these basic steps have been taken. We have also included experimental and clinical data for direct comparisons between the perfusion modes. In addition, we included several suggestions for future clinical trials for other interested investigators.
Evidence for orthopaedic surgery in the treatment of metastatic bone disease of the extremities: A review article
Authors: Malviya Ajay , Gerrand Craig
Published: September 2011

Background:

The decision to offer orthopaedic surgery to patients with metastatic bone disease is often difficult and requires an understanding of the underlying disease, the patient’s needs or wishes, the expected outcomes and the principles of surgery.

Aim:

We aimed to look at the literature to support the role of orthopaedic surgery for skeletal metastasis in improving key outcomes such as pain, quality of life and physical functioning.

Design:

Review article.

Data sources:

The ‘Dialog Datastar’ database was used to access Medline and other resources from 1951 to December 2009 using keywords ‘Metasta$’ AND ‘Bone or Skeletal’ AND ‘Results Or Outcome Or Surg$ Or Management’.

Results:

The majority of the studies that have looked at these key outcomes are limited by their design and their use of non-validated outcome measures. This study has detailed the measures to assess outcome, predict survival, predict fracture and how to arrive at key decisions, such as when to operate and when not to operate on these patients.

Conclusion:

Timely and appropriate surgical intervention reliably alleviates pain and improves quality of life and can be undertaken with few complications in most patients. Although most procedures can be undertaken by non-specialists, consultation with other members of the multidisciplinary team is mandatory, and in complex cases, referral to a specialist orthopaedic oncology centre can be helpful.
Designing Phenotyping Studies for Genetically Engineered Mice
Authors: Zeiss C. J. , Ward J. M. , Allore H. G.
Published: September 2011

A phenotyping study records physiologic or morphologic changes in an experimental animal resulting from an intervention. In mice, this intervention is most frequently genetic, but it may be any type of experimental manipulation. Accurate representation of the human condition under study is essential if the model is to yield useful conclusions. In this review, general approaches to the design of phenotyping studies are considered. These approaches take into account major sources of reduced model validity, such as unexpected phenotypic variation in mice, evolutionary divergence between mice and humans, unanticipated sources of variation, and common design errors. As poor design is the most common reason why studies fail to yield enduring results, emphasis is placed on reduction of bias, sampling, controlled study design, and appropriate statistical analysis.
Solid waste generation and decomposition using compost bin technique in Pulau Pinang, Malaysia
Authors: Akinbile Christopher O , Yusoff Mohd Suffian
Published: September 2011

Solid waste comprised of a grass clippings mixture was decomposed using a locally-made compost bin in Pulau Pinang, Malaysia, to eliminate challenges associated with improper waste disposal. Bulk density, pH, moisture content, nutrients content, nitrogen (N), phosphorus (P), potassium (K), iron (Fe), zinc (Zn), copper (Cu) and carbon/nitrogen (C/N) ratio were determined over 77 days. A 34% reduction in compost bin volume was observed and bulk density and pH were also reduced from 732 to 482 kg m−3 and 7.82 to 8.41, respectively, indicating fairly good performance. The final moisture content and C/N ratio were 44.06% and 14 : 1, respectively, and the results also showed that the presence of nutrients and heavy metals in the final compost were within acceptable limits for use as a soil conditioner. Final concentrations of N, P and K were 347 mg kg−1, 510 mg kg−1 and 14.8 g kg−1 and for heavy metals, Fe, Zn and Cu were 5308, 300 and 20 mg kg−1, respectively, which considerably assisted in the decomposition process. Processed waste materials from the bin were shown to be excellent organic fertilizers with over 75% germination index for seeds grown into bean sprouts in 72 h. An improved bin design to eliminate greenhouse gas emission into the environment is suggested
Inferring Causality through Counterfactuals in Observational Studies - Some Epistemological Issues
Authors: Russo Federica , Wunsch Guillaume , Mouchart Michel
Published: September 2011

L’inférence causale par contrefactuels dans les études observationnelles — Quelques épistémologiques : Cet article contribue au débat sur les vertus et les vices de contrefactuels comme base pour l’inférence causale. L’objectif est de mettre l’approche contrefactuelle dans une perspective épistémologique. Nous discutons d’un certain nombre de questions, allant de sa base non observable au parallélisme établi entre cette approche en statistique et en philosophie. Nous soutenons que la question n’est pas de rejeter ou d’approuver l’approche contrefactuelle par principe, mais de décider quel cadre de modélisation est préférable en fonction du contexte de la recherche.
A Note on Employment and Gross Domestic Product in Swedish Family-Owned Businesses
Authors: Bjuggren Carl Magnus , Johansson Dan , Sjögren Hans
Published: September 2011

The Swedish government gathers information that helps identify family-owned businesses and enabled the authors to analyze every business in the economy over a longer period than has heretofore been reported. Using these data, the authors found that family-owned businesses account for up to one fourth of total employment and one fifth of gross domestic product in Sweden. These shares have increased over time due, in part, to economic policy. The authors compare their findings with other studies and suggest how Sweden and other governments might make family firm data more readily available for researchers.
Vibration analysis of plane frames by customized stiffness and diagonal mass matrices
Authors: Rezaiee-Pajand M , Khajavi R
Published: September 2011

This article presents a formulation for the vibration analysis of plane frames. The strain gradient notation is utilized to determine the mass and stiffness matrices. The obtained matrices can easily be parameterized due to their simple structure. Both Euler-Bernoulli- and Timoshenko-beam elements are investigated in this study. The parameterized stiffness and mass matrices are optimized for accurate performance in the vibration analysis of frame structures. Some numerical examples are solved to show the advantages of the presented scheme. Results of these sample vibration problems indicate that the proposed technique increases the accuracy of analysis, when these new stiffness and diagonal mass matrices are used.
The conceptual design of a spatial binary hyper redundant manipulator and its forward kinematics
Authors: Bayram A , Kemal Özgören M
Published: September 2011

The hyper redundant manipulators (HRMs) have excessively many degrees of freedom. As a special but practicable subset of them, the binary hyper-redundant manipulators (BHRMs) use binary (on–off) actuators with only two stable states such as pneumatic cylinders and/or solenoids. This article describes the conceptual design of a spatial BHRM together with its forward kinematics. This BHRM consists of many modules with the same constructive characteristics. The modules increase in size from the tip to the base so that the actuator powers also increase in the same order. Each module consists of three submodules. The first and second submodules have the shapes of variable geometry trusses and they work in mutually orthogonal planes. The third submodule is a discrete twister. The manipulator is assumed to be driven by pneumatic on–off actuators. Because of the discrete nature of the on–off actuators, a small but continuously actuated six-joint manipulator is installed as the last module of the BHRM in order to compensate the discretization errors.
Experimental and numerical analysis of the unsteady influence of an inlet guide vane
Authors: Zhou L , Fan H-Z , Wei W , Cai Y-H
Published: September 2011

The unsteady inlet guide vane (IGV)–impeller–diffuser interaction in a centrifugal compressor is investigated numerically and experimentally under different IGV prewhirl angles. The influence of IGV prewhirl angle on the flowfield and the unsteadiness of the impeller and diffuser are studied, and the mechanism of the unsteady IGV–impeller–diffuser interaction is explored. Results show that quite fair quantitative agreements are achieved between the predicted and measured flowfield. The IGV wake can decrease the unsteadiness on the impeller and diffuser, and the reduction of the unsteadiness caused by the IGV is a function of the IGV prewhirl angle. The unsteadiness in the diffuser with negative IGV angles is larger than that for positive prewhirl angles. The low-frequency oscillations inside the flowfield are induced by the IGV. When IGV prewhirl occurs, the basic frequency of the unsteady flow in the vaneless diffuser is mainly half of the blade passing frequency of the impeller. In practice, the IGV prewhirl angle can be adjusted to avoid unsteady vibrations in some off-design conditions, with reliability and performance improved simultaneously.
A gait-assistive mobile robot based on a body weight support and autonomous path tracking system
Authors: Yu S-N , Jang J-H , Kim D-H , Lee J-Y , Han C-S
Published: September 2011

With the rising numbers of elderly and disabled people, the demand for welfare services using a robotic system and not involving human effort is likewise increasing. This study deals with a mobile robot system combined with a body weight support (BWS) system for gait rehabilitation. The BWS system was designed via the kinematic analysis of the robot's body-lifting characteristics and of the walking guide system that controls the total rehabilitation system integrated in the mobile robot. This mobile platform is operated by utilizing the autonomous guided vehicle driving algorithm. Especially, the method that integrates geometric path tracking and obstacle avoidance for a non-holonomic mobile robot was applied so that the system can be operated in an area where the elderly users are expected to be situated, such as in a public hospital or a rehabilitation centre. The mobile robot follows the path by moving through the turning radius supplied by the pure-pursuit method, one of the existing geometric path-tracking methods. The effectiveness of the proposed method was verified through real experiments that were conducted for path tracking with static and dynamic obstacle avoidance. Finally, through electromyography signal measurement of the subject, the performance of the proposed system in a real operation condition was evaluated.
Calibration of a six-DOF parallel manipulator for chromosome dissection
Authors: Feng J , Gao F , Zhao X
Published: September 2011

This article proposes a calibration method for a six-PPPS parallel manipulator which is the macro-part of a dual-drive chromosome dissection system. The calibration model is built with respect to Denavit–Hartenberg notation. Certain adjustment matrices are utilized to provide independent error parameters. The pose of the moving platform as while as relative motion of all prismatic joints and spherical joints are measured by the latest API T3 laser tracker. Other than general methods that need reconstruction of the location and orientation of the platform with point coordinates, these data can be obtained directly within one single measurement in the proposed method. For data processing, a step-by-step calculation method has been presented to select initial error parameters. With this method, partial error parameters can be derived in advance to be substituted into the calibration model providing calculation efficiency superior to simultaneous computation. Simulation based on the geometry of this manipulator shows a decent convergence performance of the calibration model. The experimental results also validate the efficiency and the convenience of the proposed method.
An analytical approach to the structural design and optimization of motorbike forks
Authors: Croccolo D , De Agostinis M , Vincenzi N
Published: September 2011

From a structural standpoint, motorbike forks must withstand the most diverse loading conditions that the normal use of the vehicle implies. By means of experimental analyses, the authors found the emergency braking to be the most severe loading case. This contribution presents a novel analytical model that, given a few geometric parameters of the motorbike and of the fork, allows calculation of the stress field on the legs under braking. The analytical model was designed to account for the unequal stress distribution on the two legs that arises from the geometrical asymmetry of single brake disc architectures. The model accuracy was tested by comparison with finite element analysis (FEA) and experimental stress analyses. Finally, the possibility of balancing the loads on the legs of single disc architectures was examined and some structural optimization strategies were proposed.
Copper films deposited by arc ion plating at low temperatures exhibiting excellent antiwear behaviour
Authors: Gao X-M , Hu M , Sun J-Y , Weng L-J , Zhou F , Liu W-M
Published: September 2011

Cu films were prepared by arc ion plating (AIP) at low temperature ( Ts) and investigated by X-ray diffraction, field emission scanning electron microscope atomic force microscopy, transmission electron microscope, etc. It is found that low Ts (≤ 221 K) can refine the crystallite size of the Cu films and leads to compact and smooth surface structure. Further decreasing Ts to 135 K makes the inter-grain gaps turn bigger. The wear behaviours of the Cu films in vacuum were characterized using a ball-on-disk tribometer. The results show that the Cu films deposited at the Ts range of 135–221 K have better wear resistance, and the wear rates are two to three orders lower than that of the film deposited at room temperature. The compact and dense arrangement of nanoscale crystallites significantly contributes to the improved film–substrate adhesion and so the excellent antiwear behaviour.