bluuebunny/crossref_metadata_2025 huggingface dataset:
Imaging of Subacute Blood–Brain Barrier Disruption After Methadone Overdose
Authors: Huisa Branko N. , Gasparovic Charles , Taheri Saeid , Prestopnik Jillian L. , Rosenberg Gary A.
Published: December 2011

BACKGROUND

Methadone intoxication can cause respiratory depression, leading to hypoxia with subsequent coma and death. Delayed postanoxic leukoencephalopathy (DAL) has been reported with intoxication by carbon monoxide, narcotics, and other toxins.

OBJECTIVE

To investigate the metabolic derangement of the white matter (WM) and blood–brain barrier (BBB) after DAL caused by methadone overdose.

DESIGN, SETTING, AND PATIENTS

Case report of 2 patients with DAL after a single dose of “diverted” methadone used for pain control.

RESULTS

In both cases brain magnetic resonance imaging (MRI) revealed initial extensive bilateral restricted diffusion lesions within the WM. Follow‐up MRI using proton magnetic resonance spectroscopic imaging (1H‐MRSI) showed markedly lower N‐acetylaspartate and higher choline within the WM. BBB permeability, calculated by Patlak graphical analysis of MRI T1 data obtained after contrast agent injection, showed disruption of the BBB within the WM lesions, which persisted longer than a year in 1 patient. Neuropsychological evaluation showed executive dysfunction in both patients. After 1 year, one patient recovered whereas the second remained impaired.

CONCLUSIONS

Methadone overdose can cause DAL with profound disturbances of neural metabolism and the BBB. The time course of these disturbances can be monitored with MR methods.
Voxel‐Based Statistical Analysis of Fractional Anisotropy and Mean Diffusivity in Patients with Unilateral Temporal Lobe Epilepsy of Unknown Cause
Authors: Keller Simon S. , Ahrens Tobias , Mohammadi Siawoosh , Gerdes Jan S. , Möddel Gabriel , Kellinghaus Christoph , Kugel Harald , Weber Bernd , Ringelstein E. Bernd , Deppe Michael
Published: December 2011

PURPOSE

To determine regional alterations of fractional anisotropy (FA) and mean diffusivity (MD) in patients with magnetic resonance imaging (MRI)‐negative temporal lobe epilepsy with unknown cause (TLEu) using diffusion tensor imaging (DTI) and voxel‐based statistics (VBS).

METHODS

Ten patients with left TLEu and no abnormality on conventional MRI and 81 age‐matched neurological healthy controls were studied. VBS analyses were used to compare FA and MD differences between patients and controls. All results were reported using stringent statistical thresholds corrected for multiple comparisons.

RESULTS

Patients with TLEu had widespread and bilateral reduction of white matter FA, encompassing the temporal lobes, entire corpus callosum, thalamus, and other regions relative to controls. Increased MD was more spatially limited in patients, but was also observed in the thalamus. FA of the putamen was significantly increased bilaterally in patients relative to controls, which correlated with increasing macroscopic atrophy of the putamen.

DISCUSSION

Water diffusion abnormalities are widespread and bilaterally distributed in patients with unilateral TLEu, which are beyond the resolution of conventional MRI. FA alterations are more widespread relative to MD alterations. This is the first study to show evidence of interrelated microscopic (ie, FA increase) and macroscopic (ie, atrophy) alterations of the putamen in patients with TLEu.
Cortical Activation Changes in Patients Suffering from Post‐Stroke Arm Spasticity and Treated with Botulinum Toxin A
Authors: Tomášová Zuzana , Hluštík Petr , Král Michal , Otruba Pavel , Herzig Roman , Krobot Alois , Kaňovský Petr
Published: December 2011

BACKGROUND AND PURPOSE

Botulinum toxin (BoNT) treatment relieves focal arm spasticity after stroke, likely acting at several hierarchical levels of the motor system. The central correlate of BoNT‐induced spasticity relief may be detected using repeated functional MRI (fMRI) during motor task.

METHODS

Five patients (4 males, 1 female, mean age 67 years) with hemiparesis and distal arm spasticity after chronic ischemic stroke were studied. FMRI was performed while moving the paretic hand in three sessions: before and 4 and 11 weeks after BoNT treatment.

RESULTS

Arm spasticity significantly decreased following BoNT treatment across the group (mean modified Ashworth scale change .6). FMRI prior to BoNT treatment showed extensive bilateral active networks, whereas post‐BoNT activation was limited to midline and contralateral sensorimotor cortices, and the third examination, when the toxin effect has worn off, again showed extensive activation similar to pre‐BoNT examination. Post‐BoNT session 2 compared to sessions 1 and 3 demonstrated a significantly less activation in contralateral frontoparietal areas including inferior frontal, postcentral, and middle frontal gyri as well as transient crossed cerebellar activation.

CONCLUSION

Relief of post‐stroke arm spasticity may be associated with changes at several hierarchical levels of the cortical sensorimotor system, including the prefrontal cortex.
Anterior Spinal Artery Syndrome in a Patient with Vasospasm Secondary to a Ruptured Cervical Dural Arteriovenous Fistula
Authors: Drazin Doniel , Jeswani Sunil , Shirzadi Ali , Choulakian Armen , Alexander Michael J. , Palestrant David , Schievink Wouter
Published: December 2011

BACKGROUND

Spinal dural arteriovenous fistulas (DAVF) in the cervical spine are known to cause subarachnoid hemorrhage. Vasospasm after rupture of a DAVF, however, has not previously been reported.

CASE PRESENTATION

A 48‐year‐old woman who presented with the sudden onset of altered mental status. Imaging demonstrated extensive subarachnoid hemorrhage and spinal DAVF at C1 to C2. The patient underwent a suboccipital craniotomy for DAVF ligation. On post‐operative day three, she began having acute weakness in all her extremities with proprioception and vibration preserved, whereas pain and temperature sensation was lost. An angiogram demonstrated bilateral vertebral artery vasospasm with no filling of the anterior spinal artery. Bilateral angioplasty of the vertebral arteries was performed successfully and post‐angioplasty, the right vertebral artery was filling the anterior spinal artery. The patient clinically improved. She subsequently required treatment with n‐butyl cyanoacrylic acid (nBCA) embolization and gamma knife radiosurgery to achieve obliteration of the lesion.

CONCLUSIONS

For patients with subarachnoid hemorrhage of unknown origin, differential diagnosis should include DAVF. This patient also presented with vasospasm in the context of ruptured DAVF, a complication previously unreported in the literature. This finding suggests that close monitoring for vasospasm after rupture of DAVF is warranted.
Small molecule regulators of postnatal Nkx2.5 cardiomyoblast proliferation and differentiation
Authors: Chen Wen‐Pin , Wu Sean M.
Published: December 2011

•Introduction to postnatal cardiac progenitor cells

•Methods to examine postnatal CPCs with small molecules

 ‐Transgenic mice

 ‐Cell culture

 ‐Measurement of cell proliferation

 ‐Flow cytometry

 ‐Immunofluorescence

 ‐Chemical reagents

•Results and discussion of small molecule effects on CPCs

 ‐Modulation of TGF‐β but not activin A or BMP2 signalling affects smooth muscle cell differentiation of neonatal Nkx2.5+ cardiomyoblasts

 ‐Small molecule inhibition of Alk receptors induces an expansion of neonatal Nkx2.5‐eGFP+ cells

While recent data have supported the capacity for a neonatal heart to undergo cardiomyogenesis, it is unclear whether these new cardiomyocytes arise from an immature cardiomyoblast population or from the division of mature cardiomyocytes. By following the expression of enhanced Green Fluorescent Protein (eGFP) in an Nkx2.5 enhancer‐eGFP transgenic mice, we have identified a population of immature cells that can undergo cardiomyogenic as well as smooth muscle cell differentiation in the neonatal heart. Here, we examined growth factors and small molecule regulators that potentially regulate the proliferation and cardiomyogenic versus smooth muscle cell differentiation of neonatal Nkx2.5‐GFP
+ cells in vitro. We found that A83‐01 (A83), an inhibitor of TGF‐βRI, was able to induce an expansion of neonatal Nkx2.5‐eGFP
+ cells. In addition, the ability of A83 to expand eGFP
+ cells in culture was dependent on signalling from the mitogen‐activated protein kinase kinase (MEK) as treatment with a MEK inhibitor, PD0325901, abolished this effect. On the other hand, activation of neonatal Nkx2.5‐eGFP
+ cells with TGF‐β1, but not activin A nor BMP2, led to smooth muscle cell differentiation, an effect that can be reversed by treatment with A83. In summary, small molecule inhibition of TGF‐β signalling may be a promising strategy to induce the expansion of a rare population of postnatal cardiomyoblasts.
Social cognition in euthymic bipolar disorder: systematic review and meta‐analytic approach
Authors: Samamé C. , Martino D. J. , Strejilevich S. A.
Published: December 2011

Samamé C, Martino DJ, Strejilevich SA. Social cognition in euthymic bipolar disorder: systematic review and meta‐analytic approach.

Objective:  Deficits in social cognition have been reported in euthymic subjects with bipolar disorder (BD). However, some studies have failed to find differences favoring controls. As most investigations have been conducted with small samples, they have not had sufficient power to detect statistically significant differences. Furthermore, studies communicating positive results have scarcely attempted to estimate effect sizes for patient–control differences. The aim of this study was to summarize the findings of reports on social cognition in patients with euthymic BD and to combine their data to identify possible deficits and quantify their magnitude.

Method:  Systematic literature review and meta‐analysis.

Results:  Impairments of moderate magnitude (0.5 < d < 0.8) were noted across mentalizing skills, whereas small but significant effect sizes (d < 0.5) were observed for facial emotion recognition. No patient–control differences were found for decision‐making.

Conclusion:  Meta‐analytic findings provide evidence for emotion processing and theory of mind deficits in remitted bipolar patients. However, it is not yet clear whether these areas of impairment are related to neurocognitive dysfunctions or to medication effects. The results are discussed with regard to targets for future neuropsychological research on BDs.
Brain dysfunction in fibromyalgia and somatization disorder using proton magnetic resonance spectroscopy: a controlled study
Authors: Fayed N. , Andres E. , Rojas G. , Moreno S. , Serrano‐Blanco A. , Roca M. , Garcia‐Campayo J.
Published: December 2011

Fayed N, Andres E, Rojas G, Moreno S, Serrano‐Blanco A, Roca M, Garcia‐Campayo J. Brain dysfunction in fibromyalgia and somatization disorder using proton magnetic resonance spectroscopy: a controlled study.

Objective:  To evaluate the brain metabolite patterns in patients with fibromyalgia (FM) and somatization disorder (STD) compared with healthy controls through spectroscopy techniques and correlate these patterns with psychological variables.

Method:  Design. Controlled, cross‐sectional study. Sample. Patients were recruited from primary care in Zaragoza, Spain. The control group was recruited from hospital staff. Patients were administered questionnaires on pain catastrophizing, anxiety, depression, pain, quality of life, and cognitive impairment. All patients underwent Magnetic Resonance Imaging and magnetic resonance spectroscopy (MRS).

Results:  A significant increase was found in the glutamate + glutamine (Glx) levels in the posterior cingulate cortex (PCC): 10.73 (SD: 0.49) for FM and 9.67 (SD: 1.10) for STD 9.54 (SD: 1.46) compared with controls (P = 0.043). In the FM + STD group, a correlation between Glx and pain catastrophizing in PCC (r = 0.397; P = 0.033) and between quality of life and the myo‐inositol/creatine ratio in the left hippocampus (r = −0.500; P = 0.025) was found. To conclude Glutamate seems to be relevant in the molecular processes involved in FM and STD. It also opens the door for Proton MRS (1H‐MRS) in STD and suggests that reducing glutamatergic activity through pharmacological treatment could improve the outcome of patients with FM and STD.

Conclusion:  Glutamate seems to be relevant in the molecular processes involved in FM and STD. It also opens the door for Proton MRS (1H‐MRS) in STD and suggests that reducing glutamatergic activity through pharmacological treatment could improve the outcome of patients with FM and STD.
Prominent CD56 expression by damaged and regenerating muscle fibers in the skin
Authors: Mckay Kristopher , McNiff Jennifer , Subtil Antonio
Published: December 2011

Background: Antibodies to CD56 label natural killer cells as well as tissues with neural and neuroendocrine differentiation. Despite its apparently limited distribution, other conditions may unexpectedly show strong CD56 expression.

Methods: We report three cases to document another setting with strong expression of CD56 in the skin: damaged and/or regenerating muscle fibers. One case of cutaneous lupus erythematosus, one case of lymphomatoid granulomatosis, and one case of a dermal scar adjacent to cutaneous muscle fibers were evaluated with a panel of antibodies, including CD56.

Results: All cases showed histopathologic evidence of muscle fiber damage in the setting of lymphocytic infiltration or trauma. All cases showed prominent expression of CD56 by damaged and/or regenerating muscle fibers. The degree of CD56 expression was directly proportional to the proximity to the injury site and inversely proportional to fiber diameter.

Conclusions: Even though CD56 is a useful marker for certain cytotoxic lymphomas and neural/neuroendocrine neoplasms, its expression is not limited to these conditions. Our cases highlight another unexpected example of strong CD56 expression in the skin: damaged and/or regenerating muscle fibers. The growing list of CD56‐positive conditions suggests that this marker may not be as specific as initially assumed.

Mckay K, McNiff J, Subtil A. Prominent CD56 expression by damaged and regenerating muscle fibers in the skin.
Osteochondrolipoma: a subcutaneous lipoma with chondroid and bone differentiation of the chest wall
Authors: Gru Alejandro A. , Santa Cruz Daniel J.
Published: December 2011

Lipomas are the most common subtype of benign soft tissue neoplasms and can occur anywhere in the body. Differentiation into a diversity of mesenchymal elements, such as blood vessels, fibrous tissue or muscle, is a frequent event. However, the presence of bone or cartilage in these tumors is extraordinarily rare with very few cases reported in the head and neck area. We report a case of an ‘osteochondrolipoma’ of the chest wall, in a young individual, providing a rationale in support of this as a possible and distinctive histologic subtype of lipomas, as well as discussion in the differential diagnosis of this lesion.

Gru AA, Santa Cruz, DJ. Osteochondrolipoma: a subcutaneous lipoma with chondroid and bone differentiation of the chest wall.
A comparison of echo‐enhanced voiding urosonography with X‐ray voiding cystourethrography in the first year of life
Authors: Ključevšek Damjana , Battelino Nina , Tomažič Mojca , Kersnik Levart Tanja
Published: December 2011

Background:  Second‐generation echo‐enhanced voiding urosonography (VUS) with improved contrast‐specific ultrasound (US) techniques is increasingly being used for vesicoureteric reflux (VUR) detection.

Aim:  To compare VUS with X‐ray voiding cystourethrography (VCUG) and to evaluate the predictive value of pelvicalyceal dilatation for detecting VUR in the first year of life.

Materials and methods:  Sixty‐six children younger than one were investigated by US, VUS and VCUG. VCUG represented the reference method for VUR detection.

Results:  According to VCUG, VUR was present in 16/132 (12%) renal units. VUS confirmed all these and additionally revealed VUR in 26 renal units (all together 42/132 (32%) renal units with VUR). It should be noted that all VUR detected only with VUS and missed by VCUG were of grades II and III. In 27/92 (29%) US normal and in 15/40 (37%) renal units with pelvicalyceal dilatation, VUR was detected by VUS.

Conclusion:  We believe that VUS could safely replace VCUG in VUR detection in infants, with no regard to the degree of abnormality of the upper urinary tract seen on US. VCUG should be limited only to cases where bladder and/or urethra pathology are suspected.
Perceived Interactional Justice and Trust-in-supervisor as Mediators for Paternalistic Leadership
Authors: Wu Min , Huang Xu , Li Chenwei , Liu Wu
Published: December 2011

This study identifies the influencing processes that underlie the effect of the three paternalistic leadership dimensions on subordinates' work performance/ organizational citizenship behaviours. The results, based on data collected from private firms in China, showed that perceived interactional justice mediated the effects of moral leadership and benevolent leadership on trust-in-supervisor. However, perceived interactional justice did not mediate the relationship between authoritarian leadership and trust-in-supervisor. In addition, trust-in-supervisor was found to be positively associated with work performance and organizational citizenship behaviours. Cultural and practical implications and future research directions are also discussed.
Degradation of Silicon Nitride Glow Plugs in Various Environments Part 3: NGDI Engine
Authors: Oprea Carmen , Wong Frankie , Karimi Sharif Hamed , Blair Colin , Welch Alan , Troczynski Tom
Published: December 2011

Providing a reliable hot surface ignition system (glow plug, GP) for natural gas‐direct injection engines is challenging. This paper presents experimental results of aging all‐ceramic Si3N4‐based GPs in an engine, continuing previously published results on electric and gas burner rigs. The microstructural modifications of the ceramic heater, leading to degradation and ultimately to failure, are effected by four synergistic mechanisms: electrical, chemical, mechanical, and thermal. GP lifetime in engine follows the general Arrhenius law, with activation energy of 5.2 eV, (vs 9.1 V on burner rig and 13.8 eV on electric rig, as reported previously), suggesting additional factors contributing to GP failure in the engine.
Arcminute Microkelvin Imager observations of unmatched Planck ERCSC LFI sources at 15.75 GHz
Authors:   AMI Consortium, Perrott Yvette C. , Green David A. , Davies Matthew L. , Franzen Thomas M. O. , Grainge Keith J. B. , Hobson Michael P. , Hurley-Walker Natasha , Lasenby Anthony N. , Olamaie Malak , Pooley Guy G. , Rodríguez-Gonzálvez Carmen , Saunders Richard D. E. , Scaife Anna M. M. , Schammel Michel P. , Scott Paul F. , Shimwell Timothy W. , Titterington David J. , Waldram Elizabeth M.
Published: December 2011

The Planck Early Release Compact Source Catalogue includes 26 sources with no obvious matches in other radio catalogues (of predominantly extragalactic sources). Here we present observations made with the Arcminute Microkelvin Imager Small Array (AMI SA) at 15.75 GHz of the eight unmatched sources at δ > +10°. Of the eight, four are detected and are associated with known objects. The other four are not detected with the AMI SA, and are thought to be spurious.
First stars in damped Lyα systems
Authors: Salvadori Stefania , Ferrara Andrea
Published: December 2011

In order to characterize damped Lyα absorption systems (DLAs) potentially hosting first stars, we present a novel approach to investigate DLAs in the context of Milky Way (MW) formation, along with their connection with the most metal-poor stars and local dwarf galaxies. The merger tree method previously developed is extended to include inhomogeneous reionization and metal mixing, and it is validated by matching both the metallicity distribution function of Galactic halo stars and the Fe–luminosity relation of dwarf spheroidal galaxies. The model explains the observed –Fe relation of DLAs along with the chemical abundances of [Fe/H] < −2 systems. In this picture, the recently discovered zabs≈ 2.34 C-enhanced DLA pertains to a new class of absorbers hosting first stars along with second-generation long-living low-mass stars. These ‘Population III DLAs’ are the descendants of H2-cooling minihaloes with , which virialize at z > 8 in neutral, primordial regions of the MW environment and passively evolve after a short initial period of star formation. The gas in these systems is warm K, and strongly C-enriched by long-living, extremely metal-poor stars of total mass M*≈ 102–104 M⊙.
Vibrational instability of Population III very massive main-sequence stars due to the -mechanism
Authors: Sonoi Takafumi , Umeda Hideyuki
Published: December 2011

Very massive stars are thought to be formed in the early Universe because of a lack of cooling process by heavy elements, and might have been responsible for the later evolution of the Universe. We had an interest in the vibrational stability of their evolution and have carried out a linear non-adiabatic analysis of radial and non-radial oscillations for Population III very massive main-sequence stars with . We found that only the radial fundamental mode becomes unstable due to the -mechanism for these stars. The instability appears just after the CNO cycle is activated and the nuclear energy generation rate becomes large enough to stop the pre-main-sequence contraction, and continues during the early stage of core hydrogen burning. Also, we have roughly estimated the amount of mass loss due to the instability to evaluate its significance.
Influenza‐like illness surveillance on the California‐Mexico border, 2004–2009
Authors: Kammerer Peter E. , Montiel Sonia , Kriner Paula , Bojorquez Ietza , Bejarano Ramirez Veronica , Vazquez‐Erlbeck Martha , Azziz‐Baumgartner Eduardo , Blair Patrick J.
Published: December 2011

Please cite this paper as: Kammerer et al. (2012). Influenza‐like illness surveillance on the California‐Mexico border, 2004–2009. Influenza and Other Respiratory Viruses 6(5), 358–366.

Background  Since 2004, the Naval Health Research Center, with San Diego and Imperial counties, has collaborated with the US Centers for Disease Control and Prevention to conduct respiratory disease surveillance in the US‐Mexico border region. In 2007, the Secretariat of Health, Mexico and the Institute of Public Health of Baja California joined the collaboration.

Objectives  The identification of circulating respiratory pathogens in respiratory specimens from patients with influenza‐like illness (ILI).

Methods  Demographic, symptom information and respiratory swabs were collected from enrollees who met the case definition for ILI. Specimens underwent PCR testing and culture in virology and bacteriology.

Results  From 2004 through 2009, 1855 persons were sampled. Overall, 36% of the participants had a pathogen identified. The most frequent pathogen was influenza (25%), with those aged 6–15 years the most frequently affected. In April 2009, a young female participant from Imperial County, California, was among the first documented cases of 2009 H1N1. Additional pathogens included influenza B, adenovirus, parainfluenza virus, respiratory syncytial virus, enterovirus, herpes simplex virus, Streptococcus pneumoniae, and Streptococcus pyogenes.

Conclusions  The US‐Mexico border is one of the busiest in the world, with a large number of daily crossings. Due to its traffic, this area is an ideal location for surveillance sites. We identified a pathogen in 36% of the specimens tested, with influenza A the most common pathogen. A number of other viral and bacterial respiratory pathogens were identified. An understanding of the incidence of respiratory pathogens in border populations is useful for development of regional vaccination and disease prevention responses.
Surveillance of feral cats for influenza A virus in North Central Florida
Authors: Gordy James T. , Jones Cheryl A. , Rue Joanne , Crawford Patti Cynda , Levy Julie K. , Stallknecht David E. , Tripp Ralph A. , Tompkins Stephen M.
Published: December 2011

Please cite this paper as: Gordy JT et al. (2012) Surveillance of feral cats for influenza A virus in North Central Florida. Influenza and Other Respiratory Viruses 6(5), 341–347.

Background  Transmission of highly pathogenic avian influenza and the recent pandemic H1N1 viruses to domestic cats and other felids creates concern because of the morbidity and mortality associated with human infections as well as disease in the infected animals. Experimental infections have demonstrated transmission of influenza viruses in cats.

Objectives  An epidemiologic survey of feral cats was conducted to determine their exposure to influenza A virus.

Methods  Feral cat sera and oropharyngeal and rectal swabs were collected from November 2008 through July 2010 in Alachua County, FL and were tested for evidence of influenza A virus infection by virus isolation, PCR, and serological assay.

Results and conclusions  No virus was isolated from any of 927 cats examined using MDCK cell or embryonated chicken egg culture methods, nor was viral RNA detected by RT‐PCR in 200 samples tested. However, 0.43% of cats tested antibody positive for influenza A by commercial ELISA. These results suggest feral cats in this region are at minimal risk for influenza A virus infection.
A novel approach for global mammal extinction risk reduction
Authors: Di Marco Moreno , Cardillo Marcel , Possingham Hugh P. , Wilson Kerrie A. , Blomberg Simon P. , Boitani Luigi , Rondinini Carlo
Published: December 2011

With one‐fourth of the world's mammals threatened with extinction and limited budget to save them, adopting an efficient conservation strategy is crucial. Previous approaches to setting global conservation priorities have assumed all species to have equal conservation value, or have focused on species with high extinction risk, species that may be hard to save. Here, we identify priority species for optimizing the reduction in overall extinction risk of the world's threatened terrestrial mammals. We take a novel approach and focus on species having the greatest recovery opportunity using a new conservation benefit metric: the Extinction risk Reduction Opportunity (ERO). We discover that 65–87% of all threatened and potentially recoverable species are overlooked by existing prioritization approaches. We use the ERO metric to prioritize threatened species, but the potential applications are broader; ERO has the potential to integrate with every strategy that aims to maximize the likelihood of conservation success.
Endobronchial ultrasound (EBUS) with tranbronchial needle aspiration (TBNA) versus mediastinoscopy for mediastinal staging in non‐small cell lung cancer (NSCLC) thoracic cancer
Authors: Nasir Basil , Cerfolio Robert J. , Bryant Ayesha S.
Published: December 2011

Lung cancer is the leading cause of cancer deaths worldwide and is responsible for more cancer deaths than the next three most common cancers combined. Despite common use of the best non‐invasive tests for assessing clinical stage: computed tomography (CT) and integrated positron emission tomography/computed tomography (PET/CT) using 2‐deoxy‐2‐18‐fluoro‐D‐glucose (FDG), the pathologic stage is often different. The status of mediastinal (N2) lymph nodes is paramount in guiding therapy towards surgery, chemotherapy, radiotherapy or a combination of these modalities. Accurate staging is mandatory for patients prior to commencing therapy. Invasive tests that afford tissue biopsies of N2 lymph nodes are: esophageal ultrasound with fine needle aspiration (EUS‐FNA), endobronchial ultrasound (EBUS‐TBNA), and mediastinoscopy. This review article compares the two most commonly used invasive methods to obtain tissue biopsies of mediastinal (N2) lymph nodes: mediastinoscopy and endobronchial ultrasound (EBUS).
A BIOMASS FLOW APPROACH TO POPULATION MODELS AND FOOD WEBS
Authors: GETZ WAYNE M.
Published: December 2011

AbstractThe dominant differential equation paradigm for modeling the population dynamics of species interacting in the framework of a food web retains at its core the basic prey‐predator and competition models formulated by Alfred J. Lotka (1880–1945) and Vito Volterra (1860–1940) nearly nine decades ago. This paradigm lacks a trophic‐level‐independent formulation of population growth leading to ambiguities in how to treat populations that are simultaneously both prey and predator. Also, this paradigm does not fundamentally include inertial (i.e., change resisting) processes needed to account for the response of populations to fluctuating resource environments. Here I present an approach that corrects both these deficits and provides a unified framework for accounting for biomass transformation in food webs that include both live and dead components of all species in the system. This biomass transformation formulation (BTW) allows for a unified treatment of webs that include consumers of both live and dead material—both carnivores and carcasivores, herbivores and detritivores—and incorporates scavengers, parasites, and other neglected food web consumption categories in a coherent manner. I trace how BTW is an outgrowth of the metaphysiological growth modeling paradigm and I provide a general compact formulation of BTW in terms of a three‐variable differential equation formulation for each species in the food web: viz., live biomass, dead biomass, and a food‐intake‐related measure called deficit‐stress. I then illustrate the application of this new paradigm to provide insights into two‐species competition in variable environments and discuss application of BTW to food webs that incorporate parasites and pathogens.
A BRIEF AND BIASED LOOK AT SPATIAL STRUCTURE IN ECOLOGICAL MODELS: A ROUTE TO INDIVIDUAL‐BASED MODELS
Authors: LAMBERSON ROLAND H.
Published: December 2011

AbstractThe significance of spatial structure in ecological dynamics has been recognized for more than eighty years, but only in the last quarter century have substantial numbers of ecological models incorporated spatial dynamics. This paper provides a brief look at some early models that include spatial dynamics and traces their evolution through spatially explicit models and on to individual‐based models. We conclude with a more detailed look at two of the most well developed individual‐based models, inSTREAM and MORPH.
NEW HORIZONS FOR MANAGING THE ENVIRONMENT: A REVIEW OF COUPLED SOCIAL‐ECOLOGICAL SYSTEMS MODELING
Authors: SCHLÜTER M. , MCALLISTER R. R. J. , ARLINGHAUS R. , BUNNEFELD N. , EISENACK K. , HÖLKER F. , MILNER‐GULLAND E.J. , MÜLLER B. , NICHOLSON E. , QUAAS M. , STÖVEN M.
Published: December 2011

AbstractConventional approaches to natural resource management are increasingly challenged by environmental problems that are embedded in highly complex systems with profound uncertainties. These so‐called social‐ecological systems (SESs) are characterized by strong links between the social and the ecological system and multiple interactions across spatial and temporal scales. New approaches are needed to manage those tightly coupled systems; however, basic understanding of their nonlinear behavior is still missing. Modeling is a traditional tool in natural resource management to study complex, dynamic systems. There is a long tradition of SES modeling, but the approach is now being more widely recognized in other fields, such as ecological and economic modeling, where issues such as nonlinear ecological dynamics and complex human decision making are receiving more attention. SES modeling is maturing as a discipline in its own right, incorporating ideas from other interdisciplinary fields such as resilience or complex systems research. In this paper, we provide an overview of the emergence and state of the art of this cross‐cutting field. Our analysis reveals the substantial potential of SES models to address issues that are of utmost importance for managing complex human‐environment relationships, such as: (i) the implications of ecological and social structure for resource management, (ii) uncertainty in natural and social systems and ways to address it, (iii) the role of coevolutionary processes in the dynamics of SESs, and (iv) the implications of microscale human decision making for sustainable resource management and conservation. The complexity of SESs and the lack of a common analytical framework, however, also pose significant challenges for this emerging field. There are clear research needs with respect to: (i) approaches that go beyond rather simple specifications of human decision making, (ii) development of coping strategies to deal with (irreducible) uncertainties, (iii) more explicit modeling of feedbacks between the social and ecological systems, and (iv) a conceptual and methodological framework for analyzing and modeling SESs. We provide ideas for tackling some of these challenges and indicate potential key focal areas for SES modeling in the future.
Improved Multiple Point Nonlinear Genetic Algorithm Based Performance Adaptation Using Least Square Method
Authors: Li Y.G. , Abdul Ghafir M. F. , Wang L. , Singh R. , Huang K. , Feng X. , Zhang W.
Published: December 2011

At off-design conditions, engine performance model prediction accuracy depends largely on its component characteristic maps. With the absence of actual characteristic maps, performance adaptation needs to be done for good imitations of actual engine performance. A nonlinear multiple point genetic algorithm based performance adaptation developed earlier by the authors using a set of nonlinear scaling factor functions has been proven capable of making accurate performance predictions over a wide range of operating conditions. However, the success depends on searching the right range of scaling factor coefficients heuristically, in order to obtain the optimum scaling factor functions. Such search ranges may be difficult to obtain and in many off-design adaption cases, it may be very time consuming due to the nature of the trial and error process. In this paper, an improvement on the present adaptation method is presented using a least square method where the search range can be selected deterministically. In the new method, off-design adaptation is applied to individual off-design point first to obtain individual off-design point scaling factors. Then plots of the scaling factors against the off-design conditions are generated. Using the least square method, the relationship between each scaling factor and the off-design operating condition is generated. The regression coefficients are then used to determine the search range of the scaling factor coefficients before multiple off-design points performance adaptation is finally applied. The developed adaptation approach has been applied to a model single-spool turboshaft engine and demonstrated a simpler and faster way of obtaining the optimal scaling factor coefficients compared with the original off-design adaptation method.
Vibration Behavior of Flexible Rotor System Mounted on MR Squeeze Film Damper With Thermal Growth Effect
Authors: Ghaednia Hamed , Ohadi Abdolreza
Published: December 2011

Semiactive vibration reduction devices using magnetorheological fluid (MR fluid) have proven to be effective in different engineering applications. MR squeeze film damper (MR-SFD) is one type of such devices that can be used to reduce unwanted vibration in rotary machinery. The behavior of these devices is a function of electric current, which controls the magnetic field in the lubricant and therefore causes the viscosity of MR fluid to be changed. In spite of all researches have been carried out in behavior analysis of different sorts of MR-SFDs, investigations over thermal growth effects on the efficiency of these actuators, in vibration reduction applications, are rare. In this paper, a Magnetorheological squeeze film damper (MR-SFD) has been modeled using two governing equations. First, considering the Bingham model for MR fluid (MRF), a hydrodynamic model has been presented. Second, a thermal model for the system has been modeled and used to calculate the temperature rise in the squeeze film and different damper’s components. Temperature rise in MR-SFD has been considered in this paper as a novel study. Time and frequency domain analysis using Newmark method has been performed over a finite element model of the system consisting of an unbalanced flexible rotor mounted on a pair of MR-SFDs. Obtained results show that the amplitude of rotor’s vibration is not a simple function of electrical current such that, increase in the current cannot guarantee decrease in the value of amplitude. Two major phenomena have been observed during studies; rigid dampers, and generation of new critical speed. The behavior of the rotor is deeply affected by these phenomena. The steady state response of rotor versus rotation velocity is presented for different values of electrical current, which show the effects of temperature and current on the steady state response of rotor. Generally, temperature rise results in inefficiency of MR-SFDs to suppress the vibration of the rotor, especially for rotational velocities near critical speed. Due to temperature rise, appearance of the second critical speed occurs at higher values of electrical current. In addition, it delays the “rigid damper” phenomenon causing rotor response to decrease.
A Neural Network Based Nonlinear Model of a Servopneumatic System
Authors: Falcão Carneiro J. , Gomes de Almeida F.
Published: December 2011

The use of pneumatic devices is widespread among different industrial fields, in tasks like handling or assembly. Pneumatic systems are low-cost, reliable, and compact solutions. However, its use is typically restricted to simple tasks due to the poor performance achieved in applications where accurate motion control is required. One of the key elements required to achieve a good control performance is the model of the servopneumatic system. An accurate model may be of vital importance not only in the simulation steps needed to test the control strategy but also as a part of the controller itself. This work presents a new servopneumatic system model primarily developed for control tasks, namely, to predict pneumatic and friction forces in dynamic tests. The model can also be used in simulation tasks to predict the piston position and velocity. The performance on both applications is validated experimentally.
Protonation-deprotonation equilibria in tetrapyrroles Part 2: Mono- and diprotonation of methyl pyropheophorbide a in methanolic hydrochloric acid as verified by the 1H, 13C HSQC and 1H, 15N HMBC NMR experiments
Authors: Hynninen Paavo H. , Mesilaakso Markku
Published: December 2011

The two-dimensional 1H, 13C and 1H, 15N heteronuclear single quantum coherence (HSQC) and heteronuclear multiple bond correlation (HMBC) NMR techniques were applied to investigate the formation of N-protonated cationic species of methyl pyropheophorbide a in methanolic hydrochloric acid (CD3OH-HCl). The 1H, 13C HSQC and 1H, 15N HMBC NMR spectra, recorded at the temperature of 278 K, verified that the CD3OH-HCl solution with [H]+ = 0.021 M, contained the N22-protonated monocations of methyl pyropheophorbide a, whereas the CD3OH-HCl solution with [H]+ = 5.0 M contained the N22, N24-protonated dications of the phorbin. No further protonations to form the trication or tetracation were observed. Consequently, the two middle electronic spectra, which were previously tentatively interpreted as representing the dication and trication, were now attributed to conformational alterations originating from steric hindrance between the central hydrogens and changes in counter-ion and solvation interactions and/or conformational alterations intimately connected to NH-tautomerism. These possibilities to explain the previously observed middle electronic spectra are briefly discussed.
Let the market drive deployment
Authors: Gill Phillipa , Schapira Michael , Goldberg Sharon
Published: December 2011

With a cryptographic root-of-trust for Internet routing(RPKI [17]) on the horizon, we can finally start planning the deployment of one of the secure interdomain routing protocols proposed over a decade ago (Secure BGP [22], secure origin BGP [37]). However, if experience with IPv6 is any indicator, this will be no easy task. Security concerns alone seem unlikely to provide sufficient local incentive to drive the deployment process forward. Worse yet, the security benefits provided by the S*BGP protocols do not even kick in until a large number of ASes have deployed them.

Instead, we appeal to ISPs' interest in increasing revenue-generating traffic. We propose a strategy that governments and industry groups can use to harness ISPs' local business objectives and drive global S*BGP deployment. We evaluate our deployment strategy using theoretical analysis and large-scale simulations on empirical data. Our results give evidence that the market dynamics created by our proposal can transition the majority of the Internet to S*BGP.
Finding protocol manipulation attacks
Authors: Kothari Nupur , Mahajan Ratul , Millstein Todd , Govindan Ramesh , Musuvathi Madanlal
Published: December 2011

We develop a method to help discover manipulation attacks in protocol implementations. In these attacks, adversaries induce honest nodes to exhibit undesirable behaviors by misrepresenting their intent or network conditions. Our method is based on a novel combination of static analysis with symbolic execution and dynamic analysis with concrete execution. The former finds code paths that are likely vulnerable, and the latter emulates adversarial actions that lead to effective attacks. Our method is precise (i.e., no false positives) and we show that it scales to complex protocol implementations. We apply it to four diverse protocols, including TCP, the 802.11 MAC, ECN, and SCTP, and show that it is able to find all manipulation attacks that have been previously reported for these protocols. We also find a previously unreported attack for SCTP. This attack is a variant of a TCP attack but must be mounted differently in SCTP because of subtle semantic differences between the two protocols.
NetLord
Authors: Mudigonda Jayaram , Yalagandula Praveen , Mogul Jeff , Stiekes Bryan , Pouffary Yanick
Published: December 2011

Providers of "Infrastructure-as-a-Service" need datacenter networks that support multi-tenancy, scale, and ease of operation, at low cost. Most existing network architectures cannot meet all of these needs simultaneously.

In this paper we present NetLord, a novel multi-tenant network architecture. NetLord provides tenants with simple and flexible network abstractions, by fully and efficiently virtualizing the address space at both L2 and L3. NetLord can exploit inexpensive commodity equipment to scale the network to several thousands of tenants and millions of virtual machines. NetLord requires only a small amount of offline, one-time configuration. We implemented NetLord on a testbed, and demonstrated its scalability, while achieving order-of-magnitude goodput improvements over previous approaches.
The power of prediction
Authors: Zohar Eyal , Cidon Israel , Mokryn Osnat (Ossi)
Published: December 2011

In this paper we present PACK (Predictive ACKs), a novel end-to-end Traffic Redundancy Elimination (TRE) system, designed for cloud computing customers.

Cloud-based TRE needs to apply a judicious use of cloud resources so that the bandwidth cost reduction combined with the additional cost of TRE computation and storage would be optimized. PACK's main advantage is its capability of offloading the cloud-server TRE effort to end-clients, thus minimizing the processing costs induced by the TRE algorithm.

Unlike previous solutions, PACK does not require the server to continuously maintain clients' status. This makes PACK very suitable for pervasive computation environments that combine client mobility and server migration to maintain cloud elasticity.

PACK is based on a novel TRE technique, which allows the client to use newly received chunks to identify previously received chunk chains, which in turn can be used as reliable predictors to future transmitted chunks.

We present a fully functional PACK implementation, transparent to all TCP-based applications and network devices. Finally, we analyze PACK benefits for cloud users, using traffic traces from various sources.
On blind mice and the elephant
Authors: Otto John S. , Sánchez Mario A. , Choffnes David R. , Bustamante Fabián E. , Siganos Georgos
Published: December 2011

A thorough understanding of the network impact of emerging large-scale distributed systems -- where traffic flows and what it costs -- must encompass users' behavior, the traffic they generate and the topology over which that traffic flows. In the case of BitTorrent, however, previous studies have been limited by narrow perspectives that restrict such analysis.

This paper presents a comprehensive view of BitTorrent, using data from a representative set of 500,000 users sampled over a two year period, located in 169 countries and 3,150 networks. This unique perspective captures unseen trends and reveals several unexpected features of the largest peer-to-peer system. For instance, over the past year total BitTorrent traffic has
increased by 12%
, driven by 25% increases in per-peer hourly download volume despite a 10% decrease in the average number of online peers. We also observe stronger diurnal usage patterns and, surprisingly given the bandwidth-intensive nature of the application, a close alignment between these patterns and overall traffic. Considering the aggregated traffic across access links, this has potential implications on BitTorrent-associated costs for Internet Service Providers (ISPs). Using data from a transit ISP, we find a disproportionately large impact on a commonly used burstable (95th-percentile) billing model. Last, when examining BitTorrent traffic's paths, we find that for over half its users, most network traffic never reaches large transit networks, but is instead carried by small transit ISPs. This raises questions on the effectiveness of most in-network monitoring systems to capture trends on peer-to-peer traffic and further motivates our approach.
Design space analysis for modeling incentives in distributed systems
Authors: Rahman Rameez , Vinkó Tamás , Hales David , Pouwelse Johan , Sips Henk
Published: December 2011

Distributed systems without a central authority, such as peer-to-peer (P2P) systems, employ incentives to encourage nodes to follow the prescribed protocol. Game theoretic analysis is often used to evaluate incentives in such systems. However, most game-theoretic analyses of distributed systems do not adequately model the repeated interactions of nodes inherent in such systems. We present a game-theoretic analysis of a popular P2P protocol, Bit-Torrent, that models the repeated interactions in such protocols. We also note that an analytical approach for modeling incentives is often infeasible given the complicated nature of most deployed protocols. In order to comprehensively model incentives in complex protocols, we propose a simulation-based method, which we call
Design Space Analysis
(DSA). DSA provides a tractable analysis of competing protocol variants within a detailed design space. We apply DSA to P2P file swarming systems. With extensive simulations we analyze a wide-range of protocol variants and gain insights into their robustness and performance. To validate these results and to demonstrate the efficacy of DSA, we modify an instrumented BitTorrent client and evaluate protocols discovered using DSA. We show that they yield higher system performance and robustness relative to the reference implementation.