bluuebunny/crossref_metadata_2025 huggingface dataset:
Dignity: One, Two, Three, Four, Five, Still Counting
Authors: SCHROEDER DORIS
Published: December 2009

“Dissecting Bioethics,” edited by Tuija Takala and Matti Häyry, welcomes contributions on the conceptual and theoretical dimensions of bioethics.

The section is dedicated to the idea that words defined by bioethicists and others should not be allowed to imprison people's actual concerns, emotions, and thoughts. Papers that expose the many meanings of a concept, describe the different readings of a moral doctrine, or provide an alternative angle to seemingly self-evident issues are therefore particularly appreciated.

The themes covered in the section so far include dignity, naturalness, public interest, community, disability, autonomy, parity of reasoning, symbolic appeals, and toleration.

All submitted papers are peer reviewed. To submit a paper or to discuss a suitable topic, contact Tuija Takala at tuija.takala@helsinki.fi.
Optimising waiting: a view from the English National Health Service
Authors: Harrison Anthony J. , Appleby John
Published: December 2009

Recent authors have proposed that waiting times for elective treatment should be reduced to the point where the costs of doing so exceed the benefits. This paper considers how this criterion could be put into effect. Taking benefits first it argues that these could be estimated in three different ways – social cost benefit, clinical and user valuation – that would not necessarily produce consistent results and hence a choice has to be made between them. It then considers the costs of reducing waits and argues, citing relevant evidence, that these may range widely according to whether or not reductions can be achieved through simple management measures or whether more long-term capacity is required. It concludes therefore that the apparently simple criterion proposed for defining the point where waiting times are optimal is hard to establish. Choice of criterion must be made in the light of the overall values that a given health care system is intended to promote.
Optimizing multiple dam removals under multiple objectives: Linking tributary habitat and the Lake Erie ecosystem
Authors: Zheng Pearl Q. , Hobbs Benjamin F. , Koonce Joseph F.
Published: December 2009

A model is proposed for optimizing the net benefits of removing multiple dams in U.S. watersheds of Lake Erie by quantifying impacts upon social, ecological, and economic objectives of importance to managers and stakeholders. Explicit consideration is given to the linkages between newly accessible tributary habitat and the lake's ecosystem. The model is a mixed integer linear program (MILP) that selects a portfolio of potential dam removals that could achieve the best possible value of a weighted sum of the objective(s), while still satisfying the constraints. Using response functions extracted from the Lake Erie Ecological Model and an empirical cost model, the MILP accounts for ecological and economic effects of habitat changes for both desirable native walleye and undesirable sea lamprey. The solutions show the effect on removal decisions of alternative prioritizations among cost and environmental objectives and the resulting trade‐offs among those objectives. The MILP can be used as a screening model to identify portfolios of dam removals that are potentially cost‐effective enhancements of habitat and the Lake Erie ecosystem; subsequent site‐specific studies would be needed prior to actually removing dams.
On the symmetry of the morphotropic phase boundary in ferroelectric BiScO3–PbTiO3 system
Authors: Datta K. , Gorfman S. , Thomas P. A.
Published: December 2009

A single crystal of (1−x)BiScO3−xPbTiO3 at x=0.64, which is the morphotropic phase boundary composition for this system, has been investigated utilizing two different types of diffractometry. A total of twenty different reciprocal space maps for different Bragg reflections {hkl} were collected to study their individual splittings. It has been shown that to explain the 2θ splittings observed, a two-phase model is necessary. The best model found consists of either two primitive orthorhombic or two primitive monoclinic lattices and the models previously proposed based on powder diffraction data, consisting rhombohedral or tetragonal symmetries, can be rejected.
Effect of La doping on CO adsorption at ceria surfaces
Authors: Yeriskin Irene , Nolan Michael
Published: December 2009

In this paper we use density functional theory corrected for on-site Coulomb interactions (DFT+U) to study the adsorption of CO at La-doped ceria (111) and (110) surfaces. Doping of ceria with La is known to enhance oxidation of CO to CO2 and this study investigates the atomic level details of this reaction. With La3+ doping, an [La3+–O−] defect state with an oxygen hole is formed at both surfaces. The formation energy of an oxygen vacancy is reduced and vacancy formation results in the appearance of Ce3+, instead of hole compensation. On the doped surfaces weak and strong adsorption of CO is found. In the former, the molecule remains intact. In the latter, the final adsorption species depends strongly on the surface and whether oxygen vacancies are present or not. On (111) a CO2-like species forms, while on the (110) surface, mono- or bidentate carbonates are present. La-doping of ceria surfaces shows enhanced reactivity over the undoped surfaces and we discuss the origin of the enhanced reactivity and the nature of the surface species upon CO adsorption.
Modeling the nanoscale viscoelasticity of fluids by bridging non-Markovian fluctuating hydrodynamics and molecular dynamics simulations
Authors: Voulgarakis Nikolaos K. , Satish Siddarth , Chu Jhih-Wei
Published: December 2009

A multiscale computational method is developed to model the nanoscale viscoelasticity of fluids by bridging non-Markovian fluctuating hydrodynamics (FHD) and molecular dynamics (MD) simulations. To capture the elastic responses that emerge at small length scales, we attach an additional rheological model parallel to the macroscopic constitutive equation of a fluid. The widely used linear Maxwell model is employed as a working choice; other models can be used as well. For a fluid that is Newtonian in the macroscopic limit, this approach results in a parallel Newtonian–Maxwell model. For water, argon, and an ionic liquid, the power spectrum of momentum field autocorrelation functions of the parallel Newtonian–Maxwell model agrees very well with those calculated from all-atom MD simulations. To incorporate thermal fluctuations, we generalize the equations of FHD to work with non-Markovian rheological models and colored noise. The fluctuating stress tensor (white noise) is integrated in time in the same manner as its dissipative counterpart and numerical simulations indicate that this approach accurately preserves the set temperature in a FHD simulation. By mapping position and velocity vectors in the molecular representation onto field variables, we bridge the non-Markovian FHD with atomistic MD simulations. Through this mapping, we quantitatively determine the transport coefficients of the parallel Newtonian–Maxwell model for water and argon from all-atom MD simulations. For both fluids, a significant enhancement in elastic responses is observed as the wave number of hydrodynamic modes is reduced to a few nanometers. The mapping from particle to field representations and the perturbative strategy of developing constitutive equations provide a useful framework for modeling the nanoscale viscoelasticity of fluids.
Ultrafast carrier capture in InGaAs quantum posts
Authors: Stehr D. , Morris C. M. , Talbayev D. , Wagner M. , Kim H. C. , Taylor A. J. , Schneider H. , Petroff P. M. , Sherwin M. S.
Published: December 2009

To explore the capture dynamics of photoexcited carriers in semiconductor quantum posts, optical pump terahertz (THz) probe and time-resolved photoluminescence spectroscopy were performed. The results of the THz experiment show that after ultrafast excitation, electrons relax within a few picoseconds into the quantum posts, which act as efficient traps. The saturation of the quantum post states, probed by photoluminescence, was reached at approximately ten times the quantum post density in the samples. The results imply that quantum posts are highly attractive nanostructures for future device applications.
Hybrid p-n junction light-emitting diodes based on sputtered ZnO and organic semiconductors
Authors: Na Jong H. , Kitamura M. , Arita M. , Arakawa Y.
Published: December 2009

We fabricated light-emitting hybrid p-n junction devices using low temperature deposited ZnO and organic films, in which the ZnO and the organic films served as the n- and p-type component, respectively. The devices have a rectification factor as high as ∼103 and a current density greater than 2 A/cm2. Electroluminescence of the hybrid device shows the mixture of the emission bands arising from radiative charge recombination in organic and ZnO. The substantial device properties could provide various opportunities for low cost and large area multicolor light-emitting sources.
A compact, high power, ultrafast laser mode-locked by carbon nanotubes
Authors: Sun Z. , Rozhin A. G. , Wang F. , Hasan T. , Popa D. , O’Neill W. , Ferrari A. C.
Published: December 2009

We report ultrafast highly chirped pulses from an erbium doped, nanotube-mode-locked fiber oscillator. We generate 1.6W average power and 11kW peak power by seeding a fiber amplifier. This paves the way to mode-locked all-fiber master oscillator amplifiers as economic and compact sources for high-power applications, such as micromachining and laser surgery.
Assessment of the potential risk of infection associated with Clostridium difficile from porcine xenografts
Authors: Bakri Marwah M. , Sutherland Alistair D. , Brown Derek J. , Vesely Pavel , Crossan Claire , Scobie Linda
Published: December 2009

Bakri MM, Sutherland AD, Brown DJ, Vesely P, Crossan C, Scobie L. Assessment of the potential risk of infection associated with Clostridium difficile from porcine xenografts. Xenotransplantation 2009; 16: 472–476. © 2009 John Wiley & Sons A/S.

Abstract:  There are numerous concerns over the potential for transfer of pathogens between species during clinical xenotransplantation, and although current clinical application is limited, porcine xenografts have been previously used to treat patients with severe burns. Donor animals providing the xenografts are sourced from a healthy commercial herd, however, as pigs are a known source of zoonotic agents, a number of diseases are required to be excluded from pigs used for xenotransplantation purposes. Many studies have indicated the relevance of viral zoonoses, however, little has been done with regard to the potential for transfer of pathogens related to health care associated infections. Clostridium difficile is a major cause of neonatal enteritis in pigs and an important feature of this organism is that pigs can be asymptomatic carriers. This study has examined the incidence of C. difficile PCR ribotypes present in healthy donor pigs to determine if pig faeces, and in particular, contamination of skin with faecal matter, is a potential route for the transfer of C. difficile. Animals were found to have human ribotype 017 present in the faecal matter, however, no C. difficile was isolated from skin samples taken from the same animals. In addition, due to the risk factors associated with C. difficile infection, the antimicrobial susceptibility of the C. difficile isolates has been determined.
Methods for Detection ofAlternaria padwickiiin Rice Seeds
Authors: Gutiérrez Susana Alejandra , Carmona Marcelo Anibal , Reis Erlei Melo
Published: December 2009

The fungusAlternaria padwickiihas been frequently detected in seed tests of rice collected from commercial crops in Corrientes Province, Argentina. This pathogen causes germination inhibition, seedling death or spotted grains and is the causal agent ofAlternarialeaf spot. The pathogen survives as mycelia and sclerotia on seeds, plant debris and soil. Four detection methods were compared in laboratory tests, to select the best for a quick identification of the fungus in seeds. The methods were (i) Blotter Test (ii) Potato glucose agar, (iii) Bean agar (BA) and (iv) Malt extract agar. Twenty seed samples of different varieties of rice collected from Empedrado, Goya, Itá Ibaté, La Cruz, Mercedes, Paso de los Libres and Perugorría localities (Corrientes, Argentina), were analyzed in the assays. Theanovatest and the Tukey multiple range test were applied on the data to compare theA. padwickiiincidence among the varieties and detection methods. BA method was found more sensitive than other methods forA. padwickii. The incidence values ranged from 3.6 to 76%. The statistical analysis demonstrated that the BA method was the most efficient for the detection of seed pathogens, and it could be useful in studies of transmission and chemical control.
Ubiquity of Polynucleobacter necessarius ssp. asymbioticus in lentic freshwater habitats of a heterogenous 2000 km2 area
Authors: Jezberová Jitka , Jezbera Jan , Brandt Ulrike , Lindström Eva S. , Langenheder Silke , Hahn Martin W.
Published: December 2009

We present a survey on the distribution and habitat range of Polynucleobacter necessarius ssp. asymbioticus (PnecC), a numerically and functionally important taxon in the plankton of freshwater systems. We systematically sampled stagnant freshwater habitats in a heterogeneous 2000 km2 area, together with ecologically different habitats outside this area. In total, 137 lakes, ponds and puddles were investigated, which represent an enormous diversity of habitats differing, e.g. in depth (< 10 cm – 171 m) and pH (3.9–8.5). PnecC bacteria were detected by cultivation‐independent methods in all investigated habitats, and their presence was confirmed by cultivation of strains from selected habitats representing the whole studied ecological range. The determined relative abundance of the subspecies ranged from values close to the detection limit of FISH (0.2%) to 67% (average 14.5%), and the highest observed absolute abundance was 5.3 × 106 cells ml−1. Statistical analyses revealed that the abundance of PnecC bacteria was partially controlled by factors linked to concentrations of humic substances, which support the hypothesis that these bacteria utilize photodegradation products of humic substances. Based on the revealed statistical relationships, an average relative abundance of this subspecies of 20% in global freshwater habitats was extrapolated. Our study provides important implications for the current debate on ubiquity and biogeography in microorganisms.
Minimal anatomical disruption in stoma formation: the lateral rectus abdominis positioned stoma (LRAPS)
Authors: Stephenson B. M. , Evans M. D. , Hilton J. , McKain E. S. , Williams G. L.
Published: December 2009

Aim  Parastomal hernias are difficult to manage and recent attention has focused on their prevention including the use of prophylactic mesh at the time of initial surgery.

Method  A novel ‘anatomical’ approach to stoma formation, the lateral rectus abdominis positioned stoma (LRAPS), involving minimal anterior abdominal wall disruption is described.

Results  LRAPS was carried out electively (n = 25) or as an emergency (n = 4) for benign or malignant pathology. Twenty‐two had a midline laparotomy and all types of stomas were fashioned. There were two early and three later deaths from advanced malignancy. No parastomal hernias have been detected at a mean follow‐up of 13 (range 7–18) months and none detected by CT scanning in 20 of 24 patients with colorectal cancer at a mean follow‐up of 14 (range 10–18) months.

Conclusion  LRAPS reduces the incidence of early stomal herniation.
Skin peptide defences of New Zealand frogs against chytridiomycosis
Authors: Melzer S. , Bishop P. J.
Published: December 2009

Over the past few decades, amphibian populations have undergone drastic declines on a global scale. Declines in many anuran populations have been linked to the emergent skin‐invasive amphibian chytrid fungus Batrachochytrium dendrobatidis (Bd). Antimicrobial peptides in the skin are thought to act as important components of the innate immune system that may protect some species from infectious diseases. The four archaic species of Leiopelma in New Zealand are of great conservation concern and a severe population crash of Leiopelma archeyi between 1996 and 2001 has been tentatively linked with the outbreak of Bd. Here, we investigated the in vitro activity of skin secretions of six frog species in New Zealand against Bd zoospore growth. The activity of skin secretions produced by frogs in the wild varied significantly between species, with those of Le. archeyi being the most active. The skin secretions of native Leiopelmatid species showed greater Bd zoospore inhibition (31.0–71.9%) than the naturalized Litoria species (17.4–18.2%). Leiopelma archeyi has the most active peptides, even though it is the only native species with known susceptibility to Bd infections.
Retained intrauterine fetal bone as a rare cause of secondary infertility
Authors: LANZARONE Valeria F. , PARDEY John M.
Published: December 2009

Retention of intrauterine fetal bone is a rare cause of secondary infertility that should be considered when ultrasound demonstrates strongly shadowing echodensities in the endometrial space. It seems that the bone acts as an intrauterine contraceptive device as long as it is present in the cavity. Hysteroscopy is both diagnostic and therapeutic, with a generally good prognosis for future fertility in the absence of coexisting factors.
Prevalence of interictal psychiatric disorders in patients with refractory temporal and extratemporal lobe epilepsy in Spain. A comparative study
Authors: Sanchez‐Gistau Vanessa , Pintor Luis , Sugranyes Gisela , Baillés Eva , Carreño Mar , Donaire Antonio , Boget Teresa , Setoain Xavier , Bargalló Nuria , Rumia Jordi
Published: December 2009

We aim to investigate whether temporal origin of epilepsy increases the risk of developing a psychiatric disorder and more specifically a major depressive disorder. The lack of standardized diagnostic instruments and the methodologic differences between studies highlight the fact that this issue warrants further, systematic, study. Three‐hundred eight patients with complex partial seizures were classified according to temporal or extratemporal origin, following the Commission on Classification and Terminology of the International League Against Epilepsy (ILAE), 1989 localization‐related concept. All patients were assessed using the Structured Interview for DSM‐IV axis I psychiatric disorders (SCID‐I). Lifetime and previous‐year prevalence of psychiatric disorders were compared in temporal and extratemporal subgroups, using multivariate analysis. Previous‐year major depression was significantly associated with temporal lobe origin. Our results do not support the hypothesis that patients with temporal lobe epilepsy (TLE) have more psychiatric illness in general, although they do suggest a specific connection between TLE and major depression.
Cortical Thinning in Vascular Mild Cognitive Impairment and Vascular Dementia of Subcortical Type
Authors: Seo Sang Won , Ahn Jaewon , Yoon Uicheul , Im Kiho , Lee Jong‐Min , Tae Kim Sung , Ahn Hyun‐Jung , Chin Juhee , Jeong Yong , Na Duk L.
Published: December 2009

BACKGROUND AND PURPOSE

Amnestic mild cognitive impairment (MCI) is known to be a preclinical stage of Alzheimer's disease (AD). Similarly, MCI associated with small‐vessel disease (svMCI), might be a forme froste of subcortical vascular dementia (SVaD). Patterns of cortical thinning in addition to the ischemia rating on MRI may further elucidate the clinical characteristics and pathogenesis of SVaD and svMCI. We tried to determine if svMCI differs from SVaD in the distribution of cortical atrophy, which may help understand the hierarchy between svMCI and SVaD and possibly also how svMCI evolves into SVaD.

METHODS

Twenty patients with SVaD, 34 patients with svMCI, 115 patients with AD, and 96 individuals with normal‐cognition (NC) were imaged with magnetic resonance imaging (MRI) including 3‐dimensional volumetric images for cortical thickness analysis across the entire brain.

RESULTS

Compared to NC, svMCI patients showed cortical thinning in inferior frontal and orbitofrontal gyri, anterior cingulate, insula, superior temporal gyrus, and lingual gyrus, while cortical thinning in SVaD patients involved all these areas plus dorsolateral prefrontal and temporal cortices.

CONCLUSION

Our findings suggest the presence of hierarchy between svMCI and SVaD, and that the cognitive decline from svMCI to SVaD is associated with lesions in dorsolateral prefrontal and temporal cortices.
Correlation between Cognitive Deficits and Glucose Hypometabolism in Mild Cognitive Impairment
Authors: Nishi Hiroko , Sawamoto Nobukatsu , Namiki Chihiro , Yoshida Hidefumi , Thuy Dinh Ha Duy , Ishizu Koichi , Hashikawa Kazuo , Fukuyama Hidenao
Published: December 2009

BACKGROUND

In patients with mild cognitive impairment (MCI), poor performances on delayed recall and executive function are risk factors of progression to dementia. The aim of the present study was to clarify neural correlates of these neuropsychological deficits.

METHODS

Thirty patients with amnestic MCI and 15 control subjects underwent neuropsychological tests including three‐word delayed recall, visual delayed recall of Rey complex figure (RCF), and two‐relational reasoning of Raven's colored progressive matrices (RCPM) with a 18F‐fluorodeoxyglucose (FDG)‐position emission tomography (PET) measurement of resting state. We evaluated a relationship between performance of neuropsychological tests and regional cerebral glucose metabolism using voxel‐based analysis.

RESULTS

Poor performance in three‐word delayed recall was related to glucose hypometabolism in the right medial temporal, right prefrontal, and left superior parietal cortices. The deficit in visual delayed recall of RCF correlated positively with hypometabolism in the bilateral posterior cingulate. The impairment in two‐relational reasoning was associated with hypometabolism in the right prefrontal cortex.

CONCLUSIONS

The present findings suggest that hypometabolism in the right medial temporal cortex, right prefrontal cortex, left superior parietal cortex, and bilateral posterior cingulate reflects impairments in delayed recall while hypometabolism in the right prefrontal cortex mirrors deficits in executive function in MCI.

J Neuroimaging 2010;20:29‐36.
New chloroplast primers for intraspecific variation in Dicranum scoparium Hedw. (Dicranaceae) and amplification success in other bryophyte species
Authors: LANG A. , NACIRI Y.
Published: December 2009

Primers for four loci that amplify cpDNA regions have been designed for population genetic analyses in Dicranum scoparium Hedw. and compared with trnL(UAA)5′exon‐trnF. All loci showed intraspecific variation with a number of haplotypes ranging between two and six. trnH‐psbADic showed an intercontinental disjunction, but no variability within the four Swiss populations surveyed, whereas the three remaining loci displayed intrapopulation variability in at least one population (rps19‐rpl2, rpoB, trnT‐rps4). These primers were additionally tested on 22 bryophytes and three fern species. The primers amplified mostly in mosses and liverworts, but less well in ferns, pointing to their evolutionary distance from the bryophytes.
fHANT‐AC genes of the ectomycorrhizal fungus Laccaria bicolor are not repressed by l‐glutamine allowing simultaneous utilization of nitrate and organic nitrogen sources
Authors: Kemppainen Minna J. , Alvarez Crespo Maria C. , Pardo Alejandro G.
Published: December 2009

In boreal and temperate forest ectomycorrhizal fungi play a crucial role in nitrogen cycling by assimilating nitrogenous compounds from soil and transferring them to tree hosts. The expression profile of fHANT‐AC genes, nitrate transporter (Lbnrt), nitrate reductase (Lbnr) and nitrite reductase (Lbnir), responsible for nitrate utilization in the ectomycorrhizal fungus Laccaria bicolor, was studied on variable N regimens. The three genes were shown to be under a common regulation: repressed in the presence of ammonium while growth on nitrate resulted in high transcripts accumulation. The presence of nitrate was shown not to be indispensable for activation of Laccaria fHANT‐AC as also N starvation and growth on urea and l‐asparagine resulted in high transcript levels. Equally high expression of Laccaria fHANT‐AC genes was detected in mycelia grown on variable concentrations of l‐glutamine. This finding shows that in L. bicolor N metabolite repression of fHANT‐AC is not signalled via l‐glutamine like described in ascomycetes. The expression patterns of Lbnrt and Lbnir were also studied in an Lbnr RNA‐silenced Laccaria strain. No differences were observed on the N source regulation or the degree of transcript accumulation of these genes, indicating that the presence of high nitrate reductase activity is not a core regulator of L. bicolor fHANT‐AC expression. The simultaneous utilization of nitrate and organic N sources, already suggested by high transcript levels of Laccaria fHANT‐AC genes on organic N, was supported by the increase of culture medium pH as a result of nitrate transporter activity. The possible ecological and evolutionary significance of the herein reported high regulatory flexibility of Laccaria nitrate utilization pathway for ectomycorrizal fungi and the ectomycorrhizal symbiosis is discussed.
Linear and Nonlinear Approach of Hydropneumatic Tensioner Modeling for Spar Global Performance
Authors: Yang Chan K. , Kim M. H.
Published: December 2009

This paper deals with a numerical model of top tension risers with hydropneumatic tensioner for Spar application in the Gulf of Mexico environment. The nonlinearity of the stiffness and the friction characteristics of the tensioner combined with stick-slip behavior of the riser keel joint are investigated. The relationship between tensions and strokes for the hydropneumatic tensioner is based on the ideal gas equation where the isotropic gas constant can be varied to achieve an optimum stroke design based on the tensioner stiffness. Challenges of modeling the coupling effects in the finite element (FE) method between the tensioner and hull motion are also presented. This new FE model is implemented into a fully-coupled time-domain coupled-dynamics-analysis program for floating bodies. The effect of nonlinearity of tensioner curve, tensioner friction, and riser keel friction is intensively investigated. The resultant global motion, TTR stroke, and tensions are systematically compared with those of a simple engineering approach, in which the nonlinear coupling effect is captured by linearization.
Fractal Pattern Formation at Elastic-Plastic Transition in Heterogeneous Materials
Authors: Li J. , Ostoja-Starzewski M.
Published: December 2009

Fractal patterns are observed in computational mechanics of elastic-plastic transitions in two models of linear elastic/perfectly plastic random heterogeneous materials: (1) a composite made of locally isotropic grains with weak random fluctuations in elastic moduli and/or yield limits and (2) a polycrystal made of randomly oriented anisotropic grains. In each case, the spatial assignment of material randomness is a nonfractal strict-white-noise field on a 256×256 square lattice of homogeneous square-shaped grains; the flow rule in each grain follows associated plasticity. These lattices are subjected to simple shear loading increasing through either one of three macroscopically uniform boundary conditions (kinematic, mixed-orthogonal, or static) admitted by the Hill–Mandel condition. Upon following the evolution of a set of grains that become plastic, we find that it has a fractal dimension increasing from 0 toward 2 as the material transitions from elastic to perfectly plastic. While the grains possess sharp elastic-plastic stress-strain curves, the overall stress-strain responses are smooth and asymptote toward perfectly plastic flows; these responses and the fractal dimension-strain curves are almost identical for three different loadings. The randomness in elastic moduli in the model with isotropic grains alone is sufficient to generate fractal patterns at the transition but has a weaker effect than the randomness in yield limits. As the random fluctuations vanish (i.e., the composite becomes a homogeneous body), a sharp elastic-plastic transition is recovered.
Spatial and Temporal Excitation to Generate Traveling Waves in Structures
Authors: Gabai Ran , Bucher Izhak
Published: December 2009

The problem in the creation of traveling waves is approached here from an unconventional angle. The formulation makes use of normal vibration modes, which are standing waves, to express both traveling waves and the required force distribution. It is shown that a localized force is required at any discontinuity along the structure to absorb reflected waves. This convention is demonstrated for one- and two-dimensional structures modeled as continua, and as discretized numerical approximation of the mass and stiffness matrices. Harmonic vibrations can be characterized as standing or traveling waves or as a combination of both. By applying forces that have been specially designed for the purpose, the vibratory response can become a pure traveling wave. The force distribution is important for the design of ultrasonic motors and in control applications, attempting to absorb and create outgoing and incoming waves.
An Exact Result for the Macroscopic Response of Particle-Reinforced Neo-Hookean Solids
Authors: Lopez-Pamies Oscar
Published: December 2009

Making use of an iterated homogenization procedure in finite elasticity, an exact and explicit result is derived for the macroscopic response of Neo-Hookean solids reinforced by a random and isotropic distribution of rigid particles. The key theoretical and practical features of the result are discussed in light of comparisons with recent approximations and full-field simulations.
Optimal Web Guiding
Authors: Seshadri Aravind , Pagilla Prabhakar R.
Published: December 2009

This paper presents an optimal web guiding strategy based on the dynamic analysis of the lateral web behavior and a new fiber optic lateral web position measurement sensor. First, a lateral dynamic model of a moving web is revisited with an emphasis on correct application of appropriate boundary conditions. Then the dynamic models of two common intermediate guides (remotely pivoted guide and offset-pivot guide) are investigated. The effect of various model parameters on lateral web behavior is analyzed and discussions on proper selection of the parameters are given. Based on the model analysis, we discuss the design of a linear quadratic optimal controller that is capable of accommodating structured parametric uncertainties in the lateral dynamic model. The optimal guide control system is evaluated by a series of experiments on a web platform with different web materials under various operating conditions. Implementation of the controller with a new fiber optic lateral sensor for different scenarios is discussed. Results show good guiding performance in the presence of disturbances and with uncertainties in the model parameters.
Numerical Investigation of Tearing Fracture of Wrinkled Pipe
Authors: Ahmed Arman U. , Das Sreekanta , Cheng J. J. Roger
Published: December 2009

Steel pipelines, buried in cold regions, often respond to thermal strains and/or geotechnical movement caused by factors such as thaw settlement, frost heave, and slope instability. These complex field conditions can impose large displacements on these pipelines, resulting in localized wrinkles well into the plastic range of the pipe material. Eventually, there is a possibility of a fracture occurring at a wrinkled location under continuous deformation. A recent field fracture and a failed laboratory specimen have been observed within a telescopic wrinkle under tearing action and the loading histories have been found to be monotonic, without significant strain reversals. These incidents underscore the need for a detailed investigation, which seeks to answer fundamental questions regarding this unique mode of failure. In this study, a finite element model has been developed, which is capable of accounting for material nonlinearity effects, large displacements, large rotations, initial imperfections, and possible complex contact surfaces. Based on limited test data, the comparison of the numerical and the experimental results demonstrates the ability of the present model to predict the local buckling behavior of pipes when deformed well into the postwrinkling range. The results of this analytical work include the global and local deformation patterns and a detailed assessment of the stress-strain relations at the region of the telescopic wrinkle. The results obtained from this study have recognized the occurrence of strain reversal at the sharp fold of the wrinkle on the compression side of the pipe, a phenomenon that could be considered to be the key factor for triggering this unique failure mechanism.
Design and Implementation of a Digital Multimode H∞ Controller for the Spey Turbofan Engine
Authors: Samar Raza , Postlethwaite Ian
Published: December 2009

In this paper, a 2 degrees-of-freedom multimode controller design for the Rolls Royce Spey turbofan engine is presented. The controller is designed via discrete time H∞-optimization; it provides robust stability against coprime factor uncertainty, and a degree of robust performance in the sense of making the closed-loop system match a prespecified reference model. Multimode control logic is developed to preserve structural integrity of the engine by limiting engine variables to specified safe values. A simple strategy for antiwindup and bumpless transfer between controllers, based on the Hanus anti-windup scheme (1987, “Conditioning Technique, A General Anti-Windup and Bumpless Transfer Method,” Automatica, 23(6), pp. 729–739) and the observer-based structure of the controller, is presented. The structure of the overall switched controller is described. Actual engine test results using the Spey engine test facility at Pyestock are presented. The controller is shown to perform a variety of tasks, its multimode operation is illustrated and improvements offered on existing engine control systems are discussed.
Polarization Imaging and Insect Vision
Authors: Green Adam S. , Ohmann Paul R. , Leininger Nick E. , Kavanaugh James A.
Published: December 2009

For several years we have included discussions about insect vision in the optics units of our introductory physics courses. This topic is a natural extension of demonstrations involving Brewster's reflection and Rayleigh scattering of polarized light because many insects heavily rely on optical polarization for navigation and communication. Students, especially those majoring in the life sciences, tend to find the conversation intriguing because of its interdisciplinary context. To make it even more appealing, we recently created a laboratory component that allows students to use digital cameras and polarizing filters to create polarization maps of environmental scenes and insect bodies. In this paper we describe how to do so with ImageJ, a widely used and freely available image processing program that is suitable for students with no programming experience.
Showing Area Matters: A Work of Friction
Authors: Van Domelen David
Published: December 2009

Typically, we teach the simplified friction equation of the form Fs = μsN for static friction, where Fs is the maximum static friction, μs is the coefficient of static friction, andN is the normal force pressing the surfaces together. However, this is a bit too simplified, and doesn't work well in cases where the surface area is large and the normal force small. Rather, a better model in such cases would be Fs = μsN + csA, where cs is a new coefficient for the static friction due to contact area.1 Of course, it would help for students to be able to quantitatively measure this, and that's where this paper comes in.
Exploring Rotations Due to Radiation Pressure: 2-D to 3-D Transition Is Interesting!
Authors: Waxman Michael A.
Published: December 2009

Radiation pressure is an important topic within a standard physics course (see, in particular, Refs. 1 and 2). The physics of radiation pressure is described, the magnitude of it is derived, both for the case of a perfectly absorbing surface and of a perfect reflector,1 and various applications of this interesting effect are discussed, such as space sailing1,2 or optical “tweezers.”2 There are, however, relatively few problems that are available as end-of-the-chapter exercises. Below I present a problem I composed that I assign to my students in class and that facilitates a lively class discussion. This problem is somewhat reminiscent of the setting used by P. N. Lebedev in his historic experiments on proving the existence of radiation pressure.
Mitochondrial KATPopening confers protection against lethal myocardial injury and ischaemia-induced arrhythmias in the rat heart via PI3K/Akt-dependent and -independent mechanismsThis article is one of a selection of papers published in a special issue on Advances in Cardiovascular Research.
Authors: Matejíková Jana , Ravingerová Táňa , Pancza Dezider , Čarnická Slávka , Kolář František
Published: December 2009

Opening of mitochondrial KATPchannels (mitoKATP) has been reported to underlie protection against ischaemia–reperfusion injury induced by ischaemic preconditioning (I-PC); however, the molecular mechanisms of its antiarrhythmic effect have not been fully elucidated. We explored the involvement of phosphatidylinositol 3-kinase (PI3K)/Akt in the PC-like effect of mitoKATPopener diazoxide with particular regard to its role in protection against ischaemia-induced arrhythmias. Langendorff-perfused rat hearts were subjected to 30 min LAD occlusion with or without a prior 15 min of perfusion with diazoxide (50 µmol/L) given either alone (D-PC) or in combination with the PI3K/Akt inhibitor wortmannin (100 nmol/L). In an additional protocol, ischaemia was followed by 2 h reperfusion for infarct size (IS) determination (tetrazolium staining). The total number of premature ventricular complexes over the whole period of ischaemia, episodes of ventricular tachycardia and its duration were significantly lower in the D-PC group than in the non-preconditioned controls (158 ± 20, 2 ± 0.6 and 4.6 ± 1.8 s vs. 551 ± 61, 11 ± 2 and 42 ± 8 s, respectively; p < 0.05), concomitant with a 62% reduction in the size of infarction. Wortmannin modified neither arrhythmogenesis nor IS in the non-preconditioned hearts. Bracketing of diazoxide with wortmannin did not reverse the antiarrhythmic protection, whereas the IS-limiting effect was blunted. The results indicate that in contrast with the positive role of PI3K/Akt in protection against lethal myocardial injury, its activity is not involved in suppression of ischaemia-induced arrhythmias conferred by mitoKATPopening in the rat heart.
Role of Endothelin in Mediating Soluble fms-Like Tyrosine Kinase 1–Induced Hypertension in Pregnant Rats
Authors: Murphy Sydney R. , LaMarca B. Babbette D. , Cockrell Kathy , Granger Joey P.
Published: December 2009

Although soluble fms-like tyrosine kinase 1 (sFlt-1), an antagonist of vascular endothelial growth factor and placental growth factor, has been implicated in the pathogenesis of hypertension during preeclampsia, the mechanisms whereby enhanced sFlt-1 production leads to hypertension remain unclear. Both sFlt-1 and endothelin 1 productions are elevated in women with preeclampsia and in placental ischemic animal models of preeclampsia; however, the importance of endothelin 1 and sFlt-1 interactions in the control of blood pressure during pregnancy is unknown. The purpose of this study was to determine the role of endothelin 1 in mediating sFlt-1–induced hypertension in pregnant rats. To achieve this goal, sFlt-1 (3.7 μg/kg per day for 6 days) was infused into normal pregnant rats and pregnant rats treated with a selective endothelin type A receptor antagonist, ABT 627 (5 mg/kg per day for 6 days). Plasma concentration of sFlt-1 increased from 735±34 pg/mL in normal pregnant rats to 2498±645 pg/mL (
P
<0.05) with infusion of sFlt-1. Arterial pressure increased from 100±1 mm Hg in normal pregnant rats to 122±3 mm Hg (
P
<0.05) in sFlt-1–infused rats. Chronic increases in plasma sFlt-1 in normal pregnant rats increased preproendothelin mRNA expression in the renal cortices by ≈3-fold. In addition, chronic endothelin type A receptor blockade completely abolished the blood pressure response to sFlt-1 in pregnant rats (104±3 versus 100±1 mm Hg;
P
<0.05), whereas the endothelin A receptor antagonist had no effect on arterial pressure in NP rats (105±2 versus 100±1 mm Hg). In conclusion, this study demonstrates that endothelin 1, via endothelin type A receptor activation, plays an important role in mediating the hypertension in response to excess sFlt-1 during pregnancy.
A new measurement of sequence conservation
Authors: Cai Xiaohui , Hu Haiyan , Li Xiaoman
Published: December 2009

Background

Understanding sequence conservation is important for the study of sequence evolution and for the identification of functional regions of the genome. Current studies often measure sequence conservation based on every position in contiguous regions. Therefore, a large number of functional regions that contain conserved segments separated by relatively long divergent segments are ignored. Our goal in this paper is to define a new measurement of sequence conservation such that both contiguously conserved regions and discontiguously conserved regions can be detected based on this new measurement. Here and in the following, conserved regions are those regions that share similarity higher than a pre-specified similarity threshold with their homologous regions in other species. That is, conserved regions are good candidates of functional regions and may not be always functional. Moreover, conserved regions may contain long and divergent segments.

Results

To identify both discontiguously and contiguously conserved regions, we proposed a new measurement of sequence conservation, which measures sequence similarity based only on the conserved segments within the regions. By defining conserved segments using the local alignment tool CHAOS, under the new measurement, we analyzed the conservation of 1642 experimentally verified human functional non-coding regions in the mouse genome. We found that the conservation in at least 11% of these functional regions could be missed by the current conservation analysis methods. We also found that 72% of the mouse homologous regions identified based on the new measurement are more similar to the human functional sequences than the aligned mouse sequences from the UCSC genome browser. We further compared BLAST and discontiguous MegaBLAST with our method. We found that our method picks up many more conserved segments than BLAST and discontiguous MegaBLAST in these regions.

Conclusions

It is critical to have a new measurement of sequence conservation that is based only on the conserved segments in one region. Such a new measurement can aid the identification of better local "orthologous" regions. It will also shed light on the identification of new types of conserved functional regions in vertebrate genomes [1].
Survival of cancer patients treated with mistletoe extract (Iscador): a systematic literature review
Authors: Ostermann Thomas , Raak Christa , Büssing Arndt
Published: December 2009

Background

In Europe, extracts from Viscum album (VA-E), the European white-berry mistletoe, are widely used to treat patients with cancer.

Methods

We searched several databases such as Cochrane, EMBASE, NCCAM, NLM, DIMDI, CAMbase, and Medline. Inclusion criteria were controlled clinical studies on parameters associated with survival in cancer patients treated with Iscador. Outcome data were extracted as they were given in the publication, and expressed as hazard ratios (HR), their logarithm, and the respective standard errors using standard formulas.

Results

We found 49 publications on the clinical effects of Iscador usage on survival of cancer patients which met our criteria. Among them, 41 studies and strata provided enough data to extract hazard ratios (HR) and their standard errors (Iscador versus no extra treatment). The majority of studies reported positive effects in favour of the Iscador application. Heterogeneity of study results was moderate (I2 = 38.3%, p < 0.0001). The funnel plots were considerably skewed, indicating a publication bias, a notion which is corroborated by statistical means (AC = -1.3, CI: -1.9 to -0.6, p <= 0.0001). A random effect meta-analysis estimated the overall hazard ratio at HR = 0.59 (CI: 0.53 to 0.66, p < 0.0001). Randomized studies showed less effects than non-randomized studies (ratio of HRs: 1.24, CI: 0.79 to 1.92, p = 0.35), and matched-pair studies gave significantly better results than others (ratio of HRs: 0.33; CI: 0.17 to 0.65, p = 0.0012).

Conclusions

Pooled analysis of clinical studies suggests that adjuvant treatment of cancer patients with the mistletoe extract Iscador is associated with a better survival. Despite obvious limitations, and strong hints for a publication bias which limits the evidence found in this meta-analysis, one can not ignore the fact that studies with positive effects of VA-E on survival of cancer patients are accumulating. Future studies evaluating the effects of Iscador should focus on a transparent design and description of endpoints in order to provide greater insight into a treatment often being depreciated as ineffective, but highly valued by cancer patients.
Depot-specific differences in perilipin and hormone-sensitive lipase expression in lean and obese
Authors: Ray Hind , Pinteur Claudie , Frering Vincent , Beylot Michel , Large Valérie
Published: December 2009

Background

Mainly dependent on hormone-sensitive lipase, lipolysis is differently impaired between fat depots in human obesity. Perilipin A expression is a critical element in adipocyte lipolysis. The present study aimed at comparing expression and subcellular distribution of perilipin and hormone-sensitive lipase in two abdominal adipose tissues of lean and obese women. We examined whether regional differences in perilipin expression contribute to impaired lipolytic rates.

Methods

Abdominal subcutaneous and omental adipose tissues were obtained from six lean and ten obese women. We measured total protein content and relative distribution of hormone-sensitive lipase and perilipin proteins between lipid and non-lipid fractions in tissue homogenates. Hormone-sensitive lipase and perilipin mRNA levels, adipocyte size, basal (non-stimulated) and noradrenaline-stimulated lipolysis in isolated adipocytes were determined.

Results

Adipocytes were significantly larger in the obese versus the lean women and in subcutaneous versus omental fat. Expressed as a function of cell number, basal lipolysis and noradrenaline responsiveness were higher in subcutaneous versus omental adipocytes from the obese women (P < 0.05). Despite higher or identical mRNA levels in the lean and the obese subjects and in subcutaneous and omental tissues, perilipin protein expression was lower in both depots in the obese versus the lean women, and in subcutaneous versus omental in both lean and obese women (P < 0.05). Perilipin was mostly (above 80%) present in the lipid fraction in both depots from the obese patients and the value decreased to 60% in the lean subjects (P < 0.05). Perilipin protein expression was inversely correlated to adipocyte size and basal lipolysis in both depots. Despite higher mRNA levels, hormone-sensitive lipase protein expression decreased in both depots of the obese women. Regional difference for hormone-sensitive lipase was reported in lipid fraction of subcutaneous fat of the obese subjects: hormone-sensitive lipase content was twice as low as in omental adipose tissue.

Conclusion

In both fat depots, a reduced perilipin protein expression was observed in women obesity. Perilipin protein level may contribute to differences in basal lipolysis and in adipocyte size between fat depots and may regulate lipid accumulation in adipocytes. Differences in hormone-sensitive lipase subcellular distribution were reported between fat depots in the obese women.