bluuebunny/crossref_metadata_2025 huggingface dataset:
Natural Frequency Shift in a Centrifugal Compressor Impeller for High-Density Gas Applications
Authors: Magara Yohei , Yamaguchi Kazuyuki , Miura Haruo , Takahashi Naohiko , Narita Mitsuhiro
Published: October 2012

In designing an impeller for centrifugal compressors, it is important to predict the natural frequencies accurately in order to avoid resonance caused by pressure fluctuations due to rotor-stator interaction. However, the natural frequencies of an impeller change under high-density fluid conditions. The natural frequencies of pump impellers are lower in water than in air because of the added mass effect of water, and in high-pressure compressors the mass density of the discharge gas can be about one-third that of water. So to predict the natural frequencies of centrifugal compressor impellers, the influence of the gas must be considered. We previously found in the nonrotating case that some natural frequencies of an impeller decreased under high-density gas conditions but others increased and that the increase of natural frequencies is caused by fluid-structure interaction, not only the added mass effect but also effect of the stiffness of the gas. In order to develop a method for predicting natural frequencies of centrifugal compressor impellers for high-density gas applications, this paper presents experimental results obtained using a variable-speed centrifugal compressor with vaned diffusers. The maximum mass density of its discharge gas is approximately 300 kg/m3. The vibration stress on an impeller when the compressor was speeding up or slowing down was measured by strain gauges, and the natural frequencies were determined by resonance frequencies. The results indicate that for high-density centrifugal compressors, some natural frequencies of an impeller increased in high-density gas. To predict this behavior, we developed a calculation method based on the theoretical analysis of a rotating disk. Its predictions are in good agreement with experimental results.
Numerical Simulation of Multispecies Mass Transfer in a SOFC Electrodes Layer Using Lattice Boltzmann Method
Authors: Xu Han , Dang Zheng , Bai Bo-Feng
Published: October 2012

A two-dimensional multicomponent lattice Boltzmann (LB) model based on kinetic theory for gas mixtures combined with a representative elementary volume (REV) scale LB algorithm based on the Brinkman equation for flows in porous media is developed to simulate the mass transport in the porous anode and cathode of solid oxide fuel cell (SOFC). The concentration overpotential is calculated and compared with that obtained by the extended Fick's model (FM), the dusty gas model (DGM), and the Stefan Maxwell model (SMM), as well as the experimental results. It is concluded that LB method is a much more accurate method for the simulation of mass transfer within fuel cell electrodes. Moreover, the effects of different electrode geometrical and operating parameters on concentration polarization are also investigated.
A Viscoelastic Model for the Rate Effect in Transfer Printing
Authors: Cheng H. , Li M. , Wu J. , Carlson A. , Kim S. , Huang Y. , Kang Z. , Hwang K.-C. , Rogers J. A.
Published: October 2012

Transfer printing is a volatile tool to retract micro devices from a donor substrate via elastomeric stamps, from which the devices are grown or fabricated, followed by printing to a receiver substrate where the device is assembled to an array for integration in various applications. Among the five approaches of transfer printing summarized in the paper, the viscoelastic property of stamps is widely adopted to modulate the interfacial adhesion between the stamp and devices by applying different pulling speeds. A viscoelastic model for transfer printing is analytically established. It shows that the interfacial adhesion increases with pulling speed, which is verified by the experiments and numerical simulations.
Pyramidal Lattice Structures for High Strength and Energy Absorption
Authors: Hammetter C. I. , Rinaldi R. G. , Zok F. W.
Published: October 2012

Recent developments in directed photocuring of polymers have enabled fabrication of periodic lattice structures with highly tailorable geometries. The present study addresses the mechanics of compressive deformation of such structures with emphasis on the effects of strut slenderness L/D, strut inclination angle θ, and number of repeat lattice layers N. We present analytic models and finite element calculations for a broad parameter space and identify designs that yield desirable combinations of specific strength and energy absorption. The optimal designs (those for which crushing occurs at nearly constant compressive stress) are found to be those in which there is only one pyramidal layer, the inclination angle is of intermediate value (θ = 50 deg) and the strut slenderness ratio falls below a critical value, typically L/D=4. The performance of near-optimal structures is attributable to the balance between two competing processes during plastic deformation: (i) geometric hardening associated with lateral expansion of the nodes and the struts, and (ii) geometric softening arising from the corresponding reduction in strut angle. Comparisons with stochastic foams show that the lattice structures can be designed to attain levels of energy absorption not possible by foams (by factors of 3–5 on a mass basis), albeit at higher stress levels than those required for crushing foams.
Design and dosimetric characteristics of a new endocavitary contact radiotherapy system using an electronic brachytherapy source
Authors: Richardson Susan , Garcia‐Ramirez Jose , Lu Wei , Myerson Robert J. , Parikh Parag
Published: October 2012

Purpose:

To present design aspects and acceptance tests performed for clinical implementation of electronic brachytherapy treatment of early stage rectal adenocarcinoma. A dosimetric comparison is made between the historically used Philips RT‐50 unit and the newly developed Axxent® Model S700 electronic brachytherapy source manufactured by Xoft (iCad, Inc.).

Methods:

Two proctoscope cones were manufactured by ElectroSurgical Instruments (ESI). Two custom surface applicators were manufactured by Xoft and were designed to fit and interlock with the proctoscope cones from ESI. Dose rates, half value layers (HVL), and percentage depth dose (PDD) measurements were made with the Xoft system and compared to historical RT‐50 data. A description of the patient treatment approach and exposure rates during the procedure is also provided.

Results:

The electronic brachytherapy system has a lower surface dose rate than the RT‐50. The dose rate to water on the surface from the Xoft system is approximately 2.1 Gy/min while the RT‐50 is 10–12 Gy/min. However, treatment times with Xoft are still reasonable. The HVLs and PDDs between the two systems were comparable resulting in similar doses to the target and to regions beyond the target. The exposure rate levels around a patient treatment were acceptable. The standard uncertainty in the dose rate to water on the surface is approximately ±5.2%.

Conclusions:

The Philips RT‐50 unit is an out‐of‐date radiotherapy machine that is no longer manufactured with limited replacement parts. The use of a custom‐designed proctoscope and Xoft surface applicators allows delivery of a well‐established treatment with the ease of a modern radiotherapy device. While the dose rate is lower with the use of Xoft, the treatment times are still reasonable. Additionally, personnel may stand farther away from the Xoft radiation source, thus potentially reducing radiation exposure to the operator and other personnel.
Toward quantifying the composition of soft tissues by spectral CT with Medipix3
Authors: Ronaldson J. Paul , Zainon Rafidah , Scott Nicola Jean Agnes , Gieseg Steven Paul , Butler Anthony P. , Butler Philip H. , Anderson Nigel G.
Published: October 2012

Purpose:

To determine the potential of spectral computed tomography (CT) with Medipix3 for quantifying fat, calcium, and iron in soft tissues within small animal models and surgical specimens of diseases such as fatty liver (metabolic syndrome) and unstable atherosclerosis.

Methods:

The spectroscopic method was applied to tomographic data acquired using a micro‐CT system incorporating a Medipix3 detector array with silicon sensor layer and microfocus x‐ray tube operating at 50 kVp. A 10 mm diameter perspex phantom containing a fat surrogate (sunflower oil) and aqueous solutions of ferric nitrate, calcium chloride, and iodine was imaged with multiple energy bins. The authors used the spectroscopic characteristics of the CT number to establish a basis for the decomposition of soft tissue components. The potential of the method of constrained least squares for quantifying different sets of materials was evaluated in terms of information entropy and degrees of freedom, with and without the use of a volume conservation constraint. The measurement performance was evaluated quantitatively using atheroma and mouse equivalent phantoms. Finally the decomposition method was assessed qualitatively using a euthanized mouse and an excised human atherosclerotic plaque.

Results:

Spectral CT measurements of a phantom containing tissue surrogates confirmed the ability to distinguish these materials by the spectroscopic characteristics of their CT number. The assessment of performance potential in terms of information entropy and degrees of freedom indicated that certain sets of up to three materials could be decomposed by the method of constrained least squares. However, there was insufficient information within the data set to distinguish calcium from iron within soft tissues. The quantification of calcium concentration and fat mass fraction within atheroma and mouse equivalent phantoms by spectral CT correlated well with the nominal values (R2 = 0.990 and R2 = 0.985, respectively). In the euthanized mouse and excised human atherosclerotic plaque, regions of calcium and fat were appropriately decomposed according to their spectroscopic characteristics.

Conclusions:

Spectral CT, using the Medipix3 detector and silicon sensor layer, can quantify certain sets of up to three materials using the proposed method of constrained least squares. The system has some ability to independently distinguish calcium, fat, and water, and these have been quantified within phantom equivalents of fatty liver and atheroma. In this configuration, spectral CT cannot distinguish iron from calcium within soft tissues.
Relative growth rates of two epiphytic lichens, Lobaria pulmonaria and Hypogymnia occidentalis, transplanted within and outside of Populus dripzones
Authors: Gauslaa Yngvar , Goward Trevor
Published: October 2012

Overstory Populus has been shown to facilitate establishment by cyano- and cephalolichens on conifer branches within its dripzone; though the mechanisms behind this “dripzone effect” have yet to be elucidated. Here we test the following hypotheses that throughfall from Populus: (i) elevates bark pH; (ii) increases relative growth rate in cephalolichens; and (iii) stimulates their growth through phosphorus (P) fertilization. In southern British Columbia we transplanted the cephalolichen Lobaria pulmonaria (L.) Hoffm. (promoted by dripzones) and the acidophytic chlorolichen Hypogymnia occidentalis L.H. Pike for 14 months to 26 pairs of similar-sized Picea glauca × engelmannii situated within and outside of Populus dripzones. Half of our transplants were fertilized with P. Bark pH was significantly higher on spruce branches within than outside dripzones. Relative growth rate in L. pulmonaria increased with bark pH and was slightly higher within dripzones than outside, consistent with a facilitating effect of Populus on the Lobarion community. By contrast, the addition of P decreased relative thallus area growth in L. pulmonaria and increased relative thallus area growth in H. occidentalis; though a stronger influence on growth could be attributed to variation in canopy cover and tree height. We conclude that cephalolichens in our study area are unlikely to be facilitated by P leached from Populus.
MaizeAUXIN-BINDING PROTEIN 1andAUXIN-BINDING PROTEIN 4impact on leaf growth, elongation, and seedling responsiveness to auxin and light
Authors: Jurišić-Knežev Dejana , Čudejková Mária , Zalabák David , Hlobilová Marta , Rolčík Jakub , Pěnčík Aleš , Bergougnoux Véronique , Fellner Martin
Published: October 2012

In maize, at least five auxin-binding proteins (ABPs) have been identified, yet their functions remain unclear. The present study reports the use of maize abp1, abp4, and abp1abp4 mutants to investigate the role of ABPs during maize growth and development. Single and double abp mutant plants grown in a greenhouse differ from the wild type (WT) in their leaf declination and leaf blade growth. The effect of the dark (D), blue light (BL), red light (RL), and exogenous auxin on the development of mutant seedlings was also studied. Relative to WT, etiolated mutant seedlings were shorter and showed a reduced responsiveness to exogenous auxin. In BL or RL, the responsiveness of maize seedlings to auxin was distinctly less than in D. The reducing effect of light on seedling responsiveness to auxin is mediated at least by phytochromes. The suppression of ABP1 and (or) ABP4 led to a distinct accumulation of free indole-3-acetic acid (IAA) in etiolated and light-grown seedling organs. We concluded that ABP1 and ABP4 participate in the growth of maize seedlings, mediate seedling responses to auxin, and interact with light signaling pathway(s). We also deduce a functional interaction between ABP1 and ABP4, which is that the relationship between them is light-, organ- and response-dependent.
Transpiration-dependent passive silica accumulation in cucumber (Cucumis sativus) under varying soil silicon availability
Authors: Faisal Shaji , Callis Kristine L. , Slot Martijn , Kitajima Kaoru
Published: October 2012

Regulation of the uptake of silicon (Si) varies among plant species; some species may passively transport Si, through transpiration, from soils to shoots, while others actively transport silica and deposit it in leaf tissues at high concentrations. Cucumber ( Cucumis sativus L.) accumulates moderate amounts of silica in leaves, but the relative importance of passive and active processes pertaining to silica accumulation is poorly understood. In a factorial experiment with cucumber seedlings, we manipulated transpiration rates by changing humidity and air movements around pot-grown plants receiving a daily supply of solutions containing 0, 1, 1.5, and 2 mmol Si·L–1. Higher transpiration rates resulted in significantly greater Si per unit leaf mass after 4 days, suggesting that passive processes affect the rate of silica accumulation. Actual silica accumulation during the 4-day period was significantly higher than the expected accumulation attributable to passive transport alone in 1 and 1.5 mmol Si·L–1 treatments, while passive processes alone could account for the actual silica accumulation at 2 mmol Si·L–1. We conclude that the relative importance of active and passive processes in silica deposition in cucumber leaves depends on transpiration rates and the balance between soil Si availability and plants’ demands for Si.
Differences in clonal integration between the sexes: long-term demographic patterns in the dioecious, multi-stemmed shrub Lindera triloba
Authors: Matsushita Michinari , Tomaru Nobuhiro
Published: October 2012

In clonal plants, ramets connected within a genet can share resources through clonal integration, and clonal integration often facilitates the growth and survival of young ramets. However, in dioecious plants, it is not fully understood whether female and male genets differ in their integration patterns affecting the demographic processes. To test between-sex differences in the demographic process in relation to clonal integration, we conducted a long-term census for the dioecious sprouting shrub Lindera triloba (Sieb. et Zucc.) Blume. In an old-growth forest, we selected 73 female and 82 male genets, and the recruitment, growth, and mortality of ramets within those genets were monitored over six years. Ramet recruitment was greater in males than in females, whereas ramet growth and survival rates did not differ, on average, between sexes. Females and males showed different sensitivities to factors affecting their ramet dynamics. The ramet recruitment, growth, and survival within male genets were significantly positively affected by the largest main ramet size, whereas females were not sensitive to the effect. This suggested that demographic patterns of ramets within male genets were more sensitive to assimilates translocated from the main ramets than those within female genets, and the role of clonal integration worked differently on ramet dynamics between sexes.
Hybridization betweenPyrola grandifloraandPyrola minorin West Greenland: a tension zone maintained by clonality
Authors: Hauser Thure P. , Bohr Marietta Boje , Dienst Dorte Nygaard , Nielsen Knud Brian , Philipp Marianne
Published: October 2012

Interspecific hybridization may lead to novel hybrid lineages and transfer of genetic material, possibly enabling species to expand into new habitats. Alternatively, hybrids may be inviable or sterile, constraining movement of parental species and genes into each others range. Pyrola minor (L.) and Pyrola grandiflora (Rad.) hybridize on Disko Island in Greenland. A recent study found most hybrids to be F1plants produced by P. minor mothers. Here, we test if later generation hybrids are indeed absent in a larger sample, using morphological and molecular markers. We further test if unidirectional hybridization is due to reproductive barriers. Intermediate plants were all F1hybrids from P. minor mother plants. Our analyses indicate that hybrids originated from few hybridization events and have been maintained by clonal reproduction since then. Barriers to pollen flow between the species result from a combination of few pollinators, different flower morphology and phenology, high proportions of abnormal pollen in hybrids, and reduced pollen tube growth of heterospecific and hybrid pollen. In general, pollen from P. grandiflora grew better than pollen from P. minor, which may explain the unidirectional hybridization. Hybridization between P. grandiflora and P. minor therefore seems to operate like a tension zone in which F1hybrids are maintained by clonal propagation.
Tyrosine kinase receptor alteration of renal vasoconstriction in rats is sex- and age-related
Authors: Passmore John C. , Fleming John T. , Tyagi Suresh C. , Falcone Jeff C.
Published: October 2012

Male rat renal blood vessels undergo reduced contraction to norepinephrine with aging. There is a greater renal vascular impairment in male compared with female rats. We investigated specific tyrosine kinase receptor inhibition of renal interlobar artery responsiveness to phenylephrine in male and female rats at specifically designated ages. Vessels from young male rats contracted much less to phenylephrine when the vessels were pretreated with the tyrosine kinase inhibitors Lavendustin A, HNMPA-(AM)3, or AG1478. Vessels from adult female rats pretreated with Lavendustin A showed no difference in contraction from control, but did demonstrate a slightly reduced contraction when pretreated with AG1478. Middle-aged male rat vessels treated with Lavendustin A demonstrated no inhibition, but the insulin and epidermal growth factor receptor (EGFR) antagonists both induced a decline in contraction. Vessels from aged male rats demonstrated no effect related to the 3 pretreatments. Middle-aged and aged female rats pretreated with any inhibitor demonstrated no inhibitor-dependent alterations. We conclude that maximum contraction of interlobar arteries from adult male rats is reduced when tyrosine kinase receptor activity is reduced. Female rats demonstrated much less inhibitor-related change of contraction.
The role of endothelium in the vasorelaxant effects of the essential oil of Ocimum gratissimum in aorta and mesenteric vascular bed of rats
Authors: Pires Alana F. , Madeira Socorro V. Frota , Soares Pedro M.G. , Montenegro Claudia M. , Souza Emmanuel P. , Resende Angela C. , Soares de Moura Roberto , Assreuy Ana M.S. , Criddle David N.
Published: October 2012

This study investigated the endothelium-dependent vasorelaxant effects of the essential oil of Ocimum gratissimum (EOOG) in aortas and mesenteric vascular beds isolated from rats. EOOG (3–300 µg/mL) relaxed the tonic contractions induced by phenylephrine (0.1 µmol/L) in isolated aortas in a concentration-dependent manner in both endothelium-containing and endothelium-denuded preparations. This effect was partially reversed by L-NAME (100 µmol/L) but not by indomethacin (10 µmol/L) or TEA (5 mmol/L). In mesenteric vascular beds, bolus injections of EOOG (30, 50, 100, and 300 ng) decreased the perfusion pressure induced by noradrenaline (6 µmol/L) in endothelium-intact preparations but not in those treated with deoxycholate. L-NAME (300 µmol/L) but not TEA (1 mmol/L) or indomethacin (3 µmol/L) significantly reduced the vasodilatory response to EOOG at all of the doses tested. Our data showed that EOOG exerts a dose-dependent vasodilatory response in the resistance blood vessels of rat mesenteric vascular beds and in the capacitance blood vessel, the rat aorta. This action is completely dependent on endothelial nitric oxide (NO) release in the mesenteric vascular beds but only partially dependent on NO in the aorta. These novel effects of EOOG highlight interesting differences between resistance and capacitance blood vessels.
Protective effect of C5 shRNA on myocardial ischemia–reperfusion injury in rats
Authors: Tang Kai , Cheng Yunjiu , Wu Suhua , Liu Lijuan , Cheng Lingli
Published: October 2012

Myocardial ischemia and reperfusion (MI/R) injury is associated with activation of the complement system. Complement activation generates a series of bioactive substances, including early (C3a, C3b) and terminal (C5a, C5b-9) components. The terminal complement components are key mediators of MI/R injury. This study investigated whether C5 shRNA preconditioning has protective effects following MI/R injury and its potential mechanism. Rats were injected with C5 shRNA 2 days before induction of ischemia. The effects of C5 shRNA were evaluated by the assessment of heart function, infarct size, histopathology, inflammatory cytokine levels, and the plasma level of troponin T. Akt phosphorylation was assessed by immunoblotting. C5 shRNA efficiently inhibited C5 expression both in vitro and in vivo, and attenuated MI/R injury. C5 shRNA preconditioning significantly decreased the level of troponin T and the production of pro-inflammatory cytokine. The infarct size was decreased by 40% in C5 shRNA treated rats. Akt phosphorylation increased after C5 shRNA preconditioning. These results suggest that C5 shRNA preconditioning in rats has protective effects following MI/R injury; this may be partly effected by mediating the activation of the PI3K pathway and by phosphorylation of Akt.
OPTIMIZING OXYGEN DIFFUSION IN CATHODE MATERIALS FOR SOLID OXIDE FUEL CELLS
Authors: CHRONEOS A. , PARFITT D. , VOVK R. V. , GOULATIS I. L.
Published: October 2012

Recent investigations have revealed that the Ruddlesden–Popper series ( A n+1 B n O 3n+1) and the layered perovskite Ln BaCo 2 O 5+δ (Ln = rare-earth cations) are promising as cathodes for intermediate temperature solid oxide fuel cells. For these to be economical the oxygen diffusion must be maximized. Based on atomistic simulations, we propose strategies for optimizing oxygen diffusion in these materials by modifying the oxygen stoichiometry, the composition and cation disorder. The present investigation is focused on La 2 CoO 4+δ and GdBaCo 2 O 5+δ and the results are discussed in view of recent experimental and theoretical studies.
FLUX PINNING PROPERTIES AND MAGNETIC RELAXATION OF SUPERCONDUCTING SmFe0.9Co0.1AsO
Authors: ZHUANG J. C. , SUN Y. , DING Y. , YUAN F. F. , LIU J. T. , SHI Z. X. , LI X. W.
Published: October 2012

Magnetic Co ion doped SmFeAsO polycrystal was synthesized via solid-state reaction. Resistivity, SEM and magnetic hysteresis loops (MHLs) were measured to investigate magnetic properties of the sample. Critical current densities as well as the flux pinning forces densities were estimated from MHLs. This paper reports for the first time the research of superconducting MHLs as well as magnetic relaxation properties of SmFe 0.9 Co 0.1 AsO . Results suggest that: (i) A tail effect in the resistivity measurement together with the rapid decrease in critical current densities at low fields shows the evidence for granularity of the sample; (ii) The asymmetry of the MHLs may be caused by the Bean–Livingstone (BL) surface pinning or granular nature, and none of theoretical models are suitable to the scaling behaviors of flux pinning forces densities; (iii) The anomalous tendency of the temperature dependence of magnetic relaxation rate as well as the effective pinning energy were observed, which may be attributed to the competition between the bulk pinning and the BL surface pinning.
THE THERMOPOWER IN SEMICONDUCTING THIN FILMS WITH NONPARABOLIC ENERGY BAND
Authors: GULIYEV BAHSHELI , KERIMLI GENBER
Published: October 2012

In the present work, the in-plane electron thermopower of semiconducting size-quantized films with nonparabolic energy band in a classically strong magnetic field, which is parallel to the film normal, are investigated. It was shown that, for the degenerate electron gas thermopower is a function of film thickness and electron density: for arbitrary thickness thermopower is oscillating function, with the period as a function of concentration, but with respect to concentration thermopower is monotonically increasing function. It is shown that in the case of ultrathin films (quantum wells) thermopower increases, as thickness decreases. This result is in agreement with the experimental dates on GaAs quantum wells.
THE COMPOSITION EFFECT ON THE BOWING PARAMETER IN THE CUBIC TlxAl1-xAs
Authors: GULEBAGLAN S. ERDEN
Published: October 2012

The band gap bowing parameter of the new semiconductor Tl x Al 1-x As alloys are investigated numerically based on first-principles calculations and the local density approximation. A 16-atom supercell is used to model for the ternary Tl x Al 1-x As alloys. The alloy's lattice constants obey Vegard's law well. Band gap bowing coefficients show very strong composition dependence. The results suggest that the unstrained band gap bowing parameter of the ternary Tl x Al 1-x As alloys is b = 1.9754 eV. The results also suggest that the composition-dependent band gap energy of the zincblende alloys can be expressed by a third-order polynomial equation, Eg(x) = -7.2064x3 + 14.8397x2-10.016x + 2.2217 eV .
MEASURING SPACETIME GEOMETRY OVER THE AGES
Authors: STEBBINS ALBERT
Published: October 2012

Theorists are often told to express things in the "observational plane". One can do this for spacetime geometry, considering "visual" observations of matter in our universe by a single observer over time, with no assumptions about isometries, initial conditions, nor any particular relation between matter and geometry, such as Einstein's equations. Using observables as coordinates naturally leads to a parametrization of spacetime geometry in terms of other observables, which in turn prescribes an observational program to measure the geometry. Under the assumption of vorticity-free matter flow we describe this observational program, which includes measurements of gravitational lensing, proper motion and redshift drift. Only 15% of the curvature information can be extracted without long time baseline observations, and this increases to 35% with observations that will take decades. The rest would likely require centuries of observations. The formalism developed is exact, nonperturbative, and more general than the usual cosmological analysis.
CARDIAC ARRHYTHMIA DIAGNOSIS BY HRV SIGNAL PROCESSING USING PRINCIPAL COMPONENT ANALYSIS
Authors: SREE S. VINITHA , GHISTA DHANJOO N. , NG KWAN-HOONG
Published: October 2012

An electrocardiogram (ECG) signal represents the sum total of millions of cardiac cells' depolarization potentials. It helps to identify the cardiac health of the subject by inspecting its P-QRS-T wave. The heart rate variability (HRV) data, extracted from the ECG signal, reflects the balance between sympathetic and parasympathetic components of the autonomic nervous system. Hence, HRV signal contains information on the imbalance between these two nervous system components that results in cardiac arrhythmias. Thus in this paper, we have analyzed HRV signal abnormalities to determine and classify arrhythmias. The HRV signals are non-stationary and non-linear in nature. In this work, we have used continuous wavelet transform (CWT) coupled with principal component analysis (PCA) to extract the important features from the heart rate signals. These features are fed to the probabilistic neural network (PNN) classifier, for automated classification. Our proposed system demonstrates an average accuracy of 80% and sensitivity and specificity of 82% and 85.6%, respectively, for arrhythmia detection and classification. Our system can be operated on larger data sets. Our CWT–PCA analysis resulted in eigenvalues which constituted the HRV signal analysis parameters. We have shown and plotted the distribution of the parameters' mean values and the standard deviation for arrhythmia classification. We found some overlap in the distribution of these eigenvalue parameters for the different arrhythmia classes, which mitigates the effective use of these parameters to separate out the various arrhythmia classes. Therefore, we have formulated a HRV Integrated Index (HRVID) of these eigenvalues, and determined and plotted the mean values and standard deviation of HRVID for the various arrhythmia classifications. From this information, it can be seen that the HRVID is able to distinguish among the various arrhythmia classes. Hence, we have made a case for the employment of this HRVID as an index to effectively diagnose arrhythmia disorders.
NEW SEGMENTATION METHODOLOGY FOR EXUDATE DETECTION IN COLOR FUNDUS IMAGES
Authors: FEROUI A. , MESSADI M. , HADJIDJ I. , BESSAID A.
Published: October 2012

In this work, we developed an approach based on mathematical morphology and the k-means clustering algorithm to detect hard exudates (HEs) in images taken by retinography from different diabetic patients. The presence of exudates within the macular region is a hallmark of diabetic macular edema and is detected by diagnostics with high sensitivity. In ophthalmologic images, the segmentation of HEs is essential to characterize the shape of the lesion for analysis. In this domain, several approaches have been employed for exudate extraction. Some authors have used only the mathematical morphology, but this approach does not provide very good detection of exudates. In this paper, we combined the k-means clustering algorithm and the mathematical morphology. This approach was tested on a set of 50 ophthalmologic images. The obtained results were compared with manual segmentation by an ophthalmologist.
Bis-intercalation of a cationic porphyrin dimer linked with trietylene glycol derivative to DNA from the major groove
Authors: Lee Changyun , Gong Lindan , Shon Youngku , Lee Young Sun , Lee Suk Joong , Han Sungwook , Kim Seog K.
Published: October 2012

The binding mode of a porphyrin dimer to double stranded native DNA was investigated in this study using normal electric absorption, circular dichroism (CD) and linear dichroism (LD) spectroscopies. At the time of mixing, the spectral properties of the porphyrin dimer upon its association with DNA were characterized by hypochromism and a red shift in the absorption spectrum and by complicated CD and negative LD in the Soret region. As time elapsed, the CD spectrum became a negative single band and the negative LD signal increased. These spectral changes suggested that the majority of both porphyrin moieties of the dimer intercalated between the DNA base-pairs. The changes in the spectral characteristics of the DNA bound porphyrin-dimer were similar when the minor groove of DNA was saturated by 4′,6-diamidino-2-phenylindole (DAPI), which is well-known minor groove binding molecule. The spectral properties of DAPI, which can be summarized by a large positive induced CD in the DAPI absorption region (300~400 nm) and wavelength-independent positive reduced LD, remained intact when the porphyrin dimer was present. These observations indicated that both DAPI and porphyrin bind to DNA simultaneously, and furthermore, the bis-intercalation of the porphyrin dimer occurs in the major groove.
A SEMANTIC INDEX STRUCTURE FOR MULTIMEDIA RETRIEVAL
Authors: FLEITES FAUSTO C. , CHEN SHU-CHING , CHATTERJEE KASTURI
Published: October 2012

To be effective multimedia retrieval mechanisms, index methods must provide not only efficient access but also meaningful retrieval by addressing challenges in multimedia retrieval. This article presents the AH+-tree, a height-balanced, tree-based index structure that efficiently incorporates high-level affinity information to support Content-Based Image Retrieval (CBIR) through similarity queries. The incorporation of affinity information allows the AH+-tree to address the problems of semantic gap and user perception subjectivity inherent to multimedia retrieval. Based on the Affinity-Hybrid Tree (AH-Tree), the AH+-tree utilizes affinity information in a novel way to eliminate the I/O overhead of the AH-Tree while maintaining the same functionality and quality of results. We explain the structure of the AH+-tree and implement and analyze algorithms for tree construction and similarity queries (range and nearest neighbor). Experimental results demonstrate the superior I/O efficiency of the AH+-tree over that of the AH-Tree and the M-tree without a detrimental impact on real-time costs of the retrieval process.
SPEECH SHOT EXTRACTION FROM BROADCAST NEWS VIDEOS
Authors: KUMAGAI SHOGO , DOMAN KEISUKE , TAKAHASHI TOMOKAZU , DEGUCHI DAISUKE , IDE ICHIRO , MURASE HIROSHI
Published: October 2012

We propose a method for discriminating between a speech shot and a narrated shot to extract genuine speech shots from a broadcast news video. Speech shots in news videos contain a wealth of multimedia information of the speaker, and could thus be considered valuable as archived material. In order to extract speech shots from news videos, there is an approach that uses the position and size of a face region. However, it is difficult to extract them with only such an approach, since news videos contain non-speech shots where the speaker is not the subject that appears in the screen, namely, narrated shots. To solve this problem, we propose a method to discriminate between a speech shot and a narrated shot in two stages. The first stage of the proposed method directly evaluates the inconsistency between a subject and a speaker based on the co-occurrence between lip motion and voice. The second stage of the proposed method evaluates based on the intra- and inter-shot features that focus on the tendency of speech shots. With the combination of both stages, the proposed method accurately discriminates between a speech shot and a narrated shot. In the experiments, the overall accuracy of speech shots extraction by the proposed method was 0.871. Therefore, we confirmed the effectiveness of the proposed method.
DEFORMATION OF SINGULARITIES AND THE HOMOLOGY OF INTERSECTION SPACES
Authors: BANAGL MARKUS , MAXIM LAURENTIU
Published: October 2012

While intersection cohomology is stable under small resolutions, both ordinary and intersection cohomology are unstable under smooth deformation of singularities. For complex projective algebraic hypersurfaces with an isolated singularity, we show that the first author's cohomology of intersection spaces is stable under smooth deformations in all degrees except possibly the middle, and in the middle degree precisely when the monodromy action on the cohomology of the Milnor fiber is trivial. In many situations, the isomorphism is shown to be a ring homomorphism induced by a continuous map. This is used to show that the rational cohomology of intersection spaces can be endowed with a mixed Hodge structure compatible with Deligne's mixed Hodge structure on the ordinary cohomology of the singular hypersurface. Regardless of monodromy, the middle degree homology of intersection spaces is always a subspace of the homology of the deformation, yet itself contains the middle intersection homology group, the ordinary homology of the singular space, and the ordinary homology of the regular part.
The Most Expensive One-byte Mistake
Authors: Kamp Poul-Henning
Published: October 2012

IT both drives and implements the modern Western-style economy. Thus, we regularly see headlines about staggeringly large amounts of money connected with IT mistakes. Which IT or CS decision has resulted in the most expensive mistake?
Epistemic Strategies and Games on Concurrent Processes
Authors: Chatzikokolakis Konstantinos , Knight Sophia , Palamidessi Catuscia , Panangaden Prakash
Published: October 2012

We develop a game semantics for process algebra with two interacting agents. The purpose of our semantics is to make manifest the role of knowledge and information flow in the interactions between agents and to control the information available to interacting agents. We define games and strategies on process algebras, so that two agents interacting according to their strategies determine the execution of the process, replacing the traditional scheduler. We show that different restrictions on strategies represent different amounts of information being available to a scheduler. We also show that a certain class of strategies corresponds to the syntactic schedulers of Chatzikokolakis and Palamidessi, which were developed to overcome problems with traditional schedulers modelling interaction. The restrictions on these strategies have an explicit epistemic flavour.
Decidability of Downward XPath
Authors: Figueira Diego
Published: October 2012

We investigate the satisfiability problem for downward-XPath, the fragment of XPath that includes the child and descendant axes, and tests for (in)equality of attributes’ values. We prove that this problem is decidable, EXPTIME-complete. These bounds also hold when path expressions allow closure under the Kleene star operator. To obtain these results, we introduce a Downward Data automata model (DD automata) over trees with data, which has a decidable emptiness problem. Satisfiability of downward-XPath can be reduced to the emptiness problem of DD automata and hence its decidability follows. Although downward-XPath does not include any horizontal axis, DD automata are more expressive and can perform some horizontal tests. Thus, we show that the satisfiability remains in EXPTIME even in the presence of the regular constraints expressible by DD automata. However, the same problem in the presence of any regular constraint is known to have a nonprimitive recursive complexity. Finally, we give the exact complexity of the satisfiability problem for several fragments of downward-XPath.
XFormsDB
Authors: Laine Markku , Shestakov Denis , Vuorimaa Petri
Published: October 2012

Most Web applications are based on a conventional three-tier architecture, in which the presentation, application logic, and data management are developed and maintained in separate tiers. The main disadvantage of this architecture is that it requires expertise in multiple programming languages, programming paradigms, and data models used in each tier. A single expert rarely masters all the technologies and concepts involved. In this paper, we introduce a
tier-expanding
architectural approach that unifies the client-side (presentation tier) and server-side (logic and data tiers) programming under a single model. We base our approach on a W3C-standardized client-side markup language, XForms, and its server-side extension proposed in this paper. We derive the extension requirements from the literature and use cases, and demonstrate their functionality on the example of a blog Web application. We also show how the extension can be implemented as part of a comprehensive Web application framework called
XFormsDB
. The XFormsDB framework is an extensible Web application framework built upon declarative W3C standards. It has four major advantages: (1) one programming language, (2) one data model, (3) based on W3C-standardized declarative markup, and (4) extensibility in all tiers. Our conclusion is that expanding the presentation tier to cover both application logic and data management functionality makes both the development and maintenance of small- and medium-sized Web applications easier.
Analysis of a triploid genetic algorithm over deceptive and epistatic landscapes
Authors: Li Menglin , Hill Seamus , O'Riordan Colm
Published: October 2012

This paper examines the performance of a canonical genetic algorithm (CGA) against that of the triploid genetic algorithm (TGA) introduced in [14], over a number of well known deceptive landscapes and a series of NK landscapes in order to increase our understanding of the the TGA's ability to control convergence. The TGA incorporates a mechanism to control the convergence direction instead of simply increasing the population diversity. Results indicate that the TGA appears to have the highest level of difficulty in solving problems with a disordered pattern. While these problems seem to improve the CGA's performance, it has a negative affect on the performance of the TGA. However, the results illustrate that the TGA performs better on NK-like problems (i.e. the overlapped problems) and NK problems with higher levels of epistasis.
Results from the Borexino Solar Neutrino Experiment
Authors: Calaprice Frank , Galbiati Cristiano , Wright Alex , Ianni Aldo
Published: October 2012

Borexino is a low-background liquid scintillation detector currently acquiring solar and terrestrial neutrino data at the Gran Sasso underground laboratory in Italy. Since the start of operations in 2007, Borexino has produced measurements of 7Be, 8B, and pep solar neutrinos, as well as measurements of terrestrial and long-baseline reactor antineutrinos. The measurements were made possible by the development of low-background scintillator spectroscopy that enabled direct detection of sub-MeV solar neutrinos. The general design features of the detector are described together with current results and prospects for future measurements.
The Casimir Force and Related Effects: The Status of the Finite Temperature Correction and Limits on New Long-Range Forces
Authors: Lamoreaux Steve K.
Published: October 2012

The Casimir force, predicted to exist more than half a century ago, remains at the forefront of modern physics with broad applications beyond the originally predicted attraction of uncharged plates. This review discusses recent issues, particularly the finite temperature correction and its resolution, along with limits on new long-range forces that can arise in the context of, for example, string theory. A meta-review of books and reviews is also presented.
The Nuclear Equation of State and Neutron Star Masses
Authors: Lattimer James M.
Published: October 2012

Neutron stars are valuable laboratories for the study of dense matter. Recent observations have uncovered both massive and low-mass neutron stars and have also set constraints on neutron star radii. The largest mass measurements are powerfully influencing the high-density equation of state because of the existence of the neutron star maximum mass. The smallest mass measurements, and the distributions of masses, have implications for the progenitors and formation mechanisms of neutron stars. The ensemble of mass and radius observations can realistically restrict the properties of dense matter and, in particular, the behavior of the nuclear symmetry energy near the nuclear saturation density. Simultaneously, various nuclear experiments are progressively restricting the ranges of parameters describing the symmetry properties of the nuclear equation of state. In addition, new theoretical studies of pure neutron matter are providing insights. These observational, experimental, and theoretical constraints of dense matter, when combined, are now revealing a remarkable convergence.
Chronic Thromboembolic Pulmonary Hypertension: Treat the Patient Not the Haemodynamics
Authors: Dunne Ben , van den Broek Annika , Williams Vaughan , Smith Gregory , Revesz Tamas , Edwards Mark , Gabbay Eli
Published: October 2012

Chronic thromboembolic pulmonary hypertension (CTEPH) is a disabling condition that is being increasingly recognised. It is unique as a cause of pulmonary hypertension in that it is surgically curable. We wish to highlight the importance of recognition and early referral of any patient who may have CTEPH even in the absence of resting pulmonary hypertension as excellent results can be achieved by restoring pulmonary vascular anatomy, reducing exercise-induced pulmonary hypertension, and reducing dead-space ventilation. We present a case that illustrates these points and discuss our experience as a referral centre for CTEPH.
Imaging of Postpartum Ovarian Vein Thrombosis
Authors: Bilgin Mehmet , Sevket Osman , Yildiz Seyma , Sharifov Rasul , Kocakoc Ercan
Published: October 2012

Postpartum ovarian vein thrombosis (OVT) is a rare but serious complication. Clinical findings of OVT are nonspecific. Postpartum OVT, which is a clinically difficultly diagnosed entity, must be thought of in differential diagnosis in cases of postpartum acute abdomen. OVT can be accurately diagnosed by appropriate noninvasive radiologic modalities to start early therapy with anticoagulants and intravenous antibiotics. In this paper, we review the imaging findings of a case with postpartum ovarian vein thrombosis that had been followed up for 6 months by ultrasonography (US), color Doppler US, computed tomography (CT), and magnetic resonance imaging (MRI).
Iteration Coupling Simulation of Random Waves and Wave‐Induced Currents
Authors: Zheng Jinhai , Wang Tianwen , Wang Gang , Zhang Chenming , Zhang Chi
Published: October 2012

A two‐way coupling algorithm for wave‐current interaction is developed and implemented into a nearshore circulation model to investigate the effects of fully wave‐current interaction on irregular wave transformation over an elliptic shoal. The wave field is simulated by a spectral wave model WABED, and the wave‐induced current is solved by a quasi‐three‐dimensional model WINCM. The surface roller effects are represented in the formulation of surface stress, and the roller characteristics are solved by a roller evolution model. The proposed two‐way coupling algorithm can describe both the generation of wave‐induced current and the current‐induced wave transformation, which is more physically reasonable than the one‐way approaches. The model test with a laboratory experiment shows that wave‐induced currents have an important influence on the wave transformation, for example, the wave energy defocusing due to the strong jet‐like current along the centerline of the shoal. It is revealed that the accuracy of simulated wave field can be significantly improved by taking into account the two‐way wave‐current interaction.
Effective Treatment of Rheumatoid Arthritis-Associated Interstitial Lung Disease by B-Cell Targeted Therapy with Rituximab
Authors: Hartung Wolfgang , Maier Judith , Pfeifer Michael , Fleck Martin
Published: October 2012

Rheumatoid arthritis- (RA-) associated interstitial lung disease (RA-ILD) is the extra-articular complication with most adverse impact on the quality of life and survival in RA patients. However, treatment options are limited and controlled studies are lacking. Here, we present the case of a 66-year-old patient suffering from severe RA-ILD, which has been successfully treated with Rituximab (RTX). After failure of conventional DMARD therapy, our patient showed sustained improvement of clinical pulmonary parameters as well as joint inflammation following B-cell depletion with RTX. The six-minute-walk test improved from 380 meters to 536 meters and the forced vital capacity from 2.49 liters to 3.49. The disease activity score could be reduced from 7.7 to 2.8. Therefore, RTX might be considered as an alternative treatment for RA-ILD in patients not responding to conventional DMARD therapy.