bluuebunny/crossref_metadata_2025 huggingface dataset:
Erythropoietin involves the phosphatidylinositol 3‐kinase pathway, 14‐3‐3 protein and FOXO3a nuclear trafficking to preserve endothelial cell integrity
Authors: Chong Z Z , Maiese K
Published: March 2007

Background and purpose:

Clinical indications for erythropoietin (EPO) in the vascular system reach far beyond the treatment of anemia, but the development of EPO as a non‐toxic agent rests heavily upon the cellular pathways controlled by EPO that require elucidation.

Experimental approach:

We modulated gene activity and examined cellular trafficking of critical pathways during oxidative stress that may work in concert with EPO to protect primary cerebral endothelial cells (ECs) during oxidative stress, namely protein kinase B (Akt1), 14‐3‐3 protein, the Forkhead transcription factor FOXO3a.

Key results:

Here, we show that preservation of ECs by EPO during oxygen‐glucose deprivation (OGD) required the initial activation of the phosphatidylinositol 3‐kinase (PI‐3K) pathway through Akt1, since specific pharmacological blockade of Akt1 activity or gene silencing of Akt1 prevented EC protection by EPO. EPO subsequently involved a series of anti‐apoptotic pathways to activate STAT3, STAT5, and ERK 1/2. Furthermore, EPO maintained the inhibitory phosphorylation and integrity of the ‘pro‐apoptotic’ transcription factor FOXO3a, promoted the binding of FOXO3a to 14‐3‐3 protein and regulated the intracellular trafficking of FOXO3a. Additionally, gene silencing of FOXO3a during OGD significantly increased EC survival, but did not synergistically improve cytoprotection by EPO, illustrating that EPO relied upon the blockade of the FOXO3a pathway.

Conclusions and implications:

Our work defines a novel cytoprotective pathway in ECs that involves PI‐3 K, STAT3, STAT5, ERK 1/2, 14‐3‐3 protein and FOXO3a, which can be targeted for the development of EPO as a clinically effective and safe agent in the vascular system.

British Journal of Pharmacology (2007) 150, 839–850. doi:10.1038/sj.bjp.0707161
A Critical Compilation of Atomic Transition Probabilities for Neutral and Singly Ionized Iron
Authors: Fuhr J. R. , Wiese W. L.
Published: March 2007

We have carried out a new, expanded tabulation of the atomic transition probabilities for allowed and forbidden lines of Fe I and Fe II, based on the critical evaluation of all available literature sources. The compiled data are taken mainly from recent experimental and theoretical results that became available after the publication of our first compilation in 1988. The data are arranged in multiplet format and are ordered according to increasing excitation energies.
Study of the microscopic structures in 0.72Pb(Mg1∕3Nb2∕3)O3-0.28PbTiO3 relaxor ferroelectrics by means of x-ray diffraction
Authors: Guo Zhi , Tai Renzhong , Xu Hongjie , Gao Chen , Luo Haosu , Pan Guoqiang , Hu Chuansheng , Lin Di , Fan Rong , Li Ruipeng , Yan Rui , Zhang Xiangzhi , Namikawa Kazumichi
Published: March 2007

X-ray diffraction experiment has been conducted to study the microscopic-scale structures for 0.72PMN-0.28PT relaxor ferroelectrics in a high external dc field during phase transition. Clear quasiperiodic structures were observed along ⟨111⟩ and ⟨1–11⟩ directions near TC. These structures are interpreted as originating from strong Coulomb interactions among adjacent polar clusters. The projected cluster size (correlation length) was estimated to be 17nm. It was also found that the dominating cluster’s orientation and their interaction direction (periodic direction) were changeable among ⟨111⟩ and ⟨1–11⟩ as temperature changed.
The spatial relationships between dissipation and production rates and vortical structures in turbulent boundary and mixing layers
Authors: Diorio James , Kelley Douglas H. , Wallace James M.
Published: March 2007

A novel approach for studying the spatial relationship between the production and dissipation rates of turbulent kinetic energy and vortical structures is presented. Two turbulent flows were investigated: the zero pressure gradient boundary layer and the two-stream mixing layer. In both flows, a multisensor hot-wire probe was used to measure the velocity components in all three coordinate directions, as well as six components of the velocity gradient tensor. The remaining three velocity gradients were determined using Taylor’s hypothesis. With these data, the “instantaneous” production and dissipation rates, defined by P=−(∂U¯i∕∂xj)uiuj and D=−ν[(∂ui∕∂xj)2+(∂ui∕∂xj)(∂uj∕∂xi)], respectively, were determined. Cross-correlating the fluctuations of these two signals reveals that they are not randomly distributed in time with respect to each other; rather they display significant levels of correlation. Plotting the cross-correlation coefficients versus a dimensionless length scale, defined as L′=sgn(τ)∣τ∣∕νU¯, reveals an asymmetric pattern that persists at several cross-stream locations for both flows. Furthermore, correlating both the dissipation and production rates with a vortex identifier, ωxy=[(ωx)2+(ωy)2]1∕2, also reveals consistent cross-stream patterns. The magnitude of these correlations and their persistent shapes across the flows suggest that the spatial separation between regions of concentrated dissipation and production rates is associated with the presence of quasistreamwise vortices in both of these flows. More specifically, they imply that regions of concentrated rates of dissipation are primarily in the cores of the vortices, whereas regions of rates of production are more concentrated on their periphery.
Shape transitions in lipid membranes and protein mediated vesicle fusion and fission
Authors: Atilgan Erdinç , Sun Sean X.
Published: March 2007

In the cell, the plasma membrane is often densely decorated by transmembrane proteins. The morphology and dynamics of the membrane are strongly influenced by the presence of proteins. In this paper, we use a coarse-grained model to explore the composite membrane-protein system and develop a simulation methodology based on thermodynamic integration to examine free energy changes during membrane shape transitions. The authors show that a critical concentration of conical membrane proteins or proteins with nonzero spontaneous curvature can drive the formation of small vesicles. The driving force of vesicle budding stems from the preference of proteins to gather in regions of high curvature. A sufficiently high concentration of proteins therefore can influence the topology of the membrane. The biological significance of our results is discussed.
Electronic states on a lattice in periodic magnetic fields
Authors: Guil Francisco
Published: March 2007

The Hamiltonian for an electron in Z2, interacting with a perpendicular periodic magnetic field, is shown to be gauge equivalent to a periodic Hamiltonian. The wave function of the system is computed in terms of a ground state of the continuous motion in R2 for the Pauli Hamiltonian. Explicit expressions for the states, in both the Coulomb and Landau gauges, are considered.
Computational study of hydrogen storage in organometallic compounds
Authors: Weck Philippe F. , Dhilip Kumar T. J. , Kim Eunja , Balakrishnan Naduvalath
Published: March 2007

The authors have performed a systematic computational study of the hydrogen storage capacity of model organometallic compounds consisting of Sc, Ti, and V transition metal atoms bound to CmHm rings (m=4–6). For all the complexes considered, the hydrogen storage capacity is limited by the 18-electron rule. The maximum retrievable H2 uptake predicted is 9.3wt% using ScC4H4, slightly better than the 9.1wt% hydrogen using TiC4H4, and much larger than the ∼7wt% hydrogen with VC4H4, where only four H2 molecules can be adsorbed. The kinetic stability of these hydrogen-covered organometallic complexes is reviewed in terms of the energy gap between the highest occupied and lowest unoccupied molecular orbitals and the strength and nature of successive H2 bindings.
On the production of energetic neutrals in the cathode sheath of direct-current discharges
Authors: Ito Tsuyohito , Cappelli Mark A.
Published: March 2007

Direct measurements of the energy distribution of energetic neutrals incident onto the cathode of a dc glow discharge are presented. The measurements are performed by time-of-flight analysis of neutrals escaping through a cathode orifice. The experimental results are found to be in excellent agreement with Monte Carlo simulations, although the forward angle of the neutrals considered is limited in the present experimental configuration. It is found that the commonly used theories for the production of energetic neutrals through charge exchange in the cathode sheath do not capture the neutral energy distribution over the range of discharge voltage studied.
Seeing is believing? Sonographic artifacts
Authors: Kremkau Frederick W.
Published: March 2007

Several physical assumptions go into the production of a sonogram from an ultrasound examination. When those assumptions are violated, the sonogram incorrectly images anatomical structures and blood flow.
Comparison of Acute Physiology and Chronic Health Evaluation (APACHE) II score with organ failure scores to predict hospital mortality
Authors: Ho K. M. , Lee K. Y. , Williams T. , Finn J. , Knuiman M. , Webb S. A. R.
Published: March 2007

This study compared the performance of the Acute Physiology and Chronic Health Evaluation (APACHE) II score with two organ failure scores in predicting hospital mortality of critically ill patients. A total of 1311 consecutive adult patients in a tertiary 22‐bed multidisciplinary intensive care unit (ICU) in Western Australia were considered. The APACHE II score had a better calibration and discrimination than the Max Sequential Organ Failure Score (Max SOFA) (area under receiver operating characteristic (ROC) curve 0.858 vs 0.829), Admission SOFA (area under ROC 0.858 vs 0.791), and the first day or cumulative 5‐day Royal Perth Hospital Intensive Care Unit (RPHICU) organ failure score (area under ROC 0.858 vs 0.822 and 0.819, respectively) in predicting hospital mortality. The APACHE II score predicted hospital mortality of critically ill patients better than the SOFA and RPHICU organ failure scores in our ICU.
Ecological implications of intertidal mariculture: observed differences in bivalve community structure between farm and reference sites
Authors: WHITELEY JONATHAN , BENDELL‐YOUNG LEAH
Published: March 2007

Despite recent growth in shellfish aquaculture in British Columbia, Canada, the impacts of common practices on non‐target species are poorly understood. Two practices employed on clam farms to increase production of the exotic clam Venerupis philippinarum include the addition of juvenile ‘seed’ clams to the sediment and covering seeded clam beds with protective netting, ostensibly to exclude large mobile epibenthic predators.

We expected the effects of predator exclusion to be most evident among other bivalves, which made up more than 80% of the infaunal macrobenthos at all sites surveyed. A field study across three regions collected infaunal bivalve density and biomass data. We compared species richness, composition and abundances of communities between clam farms and reference sites, paired on the basis of physical characteristics such as sediment type, slope and aspect.

Venerupis philippinarum was the only species found in higher abundance on farm sites in low intertidal areas (227 ± 241·6 clams m−2, P= 0·02; 872·9 ± 792·9 g m−2, P= 0·037). Farmed sites showed no difference in mid‐intertidal areas, nor in density of the other 25 bivalve species, although an increase would be expected if netting excluded important predators. Although statistically non‐significant, there were indications that biomass of species other than V. philippinarum may have been lower on farm sites.

Bivalve species composition was not significantly different between farm and reference sites. Nevertheless, farm sites were more similar to each other as a group than reference sites, leading to a loss of regional distinctness that was evident among reference sites.

Synthesis and applications. Our findings support the hypothesis that predation and competition play minor roles in structuring communities in soft‐bottomed environments. Given the potential for cumulative effects of seeding and netting at large scales, a precautionary approach is recommended in future development of intertidal clam aquaculture.
A functional genetic assay for nuclear trafficking in plants
Authors: Kanneganti Thirumala‐Devi , Bai Xiaodong , Tsai Chi‐Wei , Win Joe , Meulia Tea , Goodin Michael , Kamoun Sophien , Hogenhout Saskia A.
Published: March 2007

The receptor importin‐α mediates the nuclear import of functionally diverse cargo proteins that contain arginine/lysine‐rich nuclear localization signals (NLSs). Functional homologs of importin‐α have been characterized in a wide range of species including yeast, human and plants. However, the differential cargo selectivity of plant importin‐α homologs has not been established. To advance nuclear import studies conducted in plant cells, we have developed a method that allows importin‐α‐dependent nuclear import to be assayed in Nicotiana benthamiana. We employed virus‐induced gene silencing (VIGS) to knock down the expression of two importin‐α homologs, NbImpα1 and NbImpα2, which we identified from N. benthamiana. Agro‐infiltration was then used to transiently express the NLS‐containing proteins Arabidopsis thaliana fibrillarin 1 (AtFib1) and the Nuk6, Nuk7 and Nuk12 candidate effector proteins of the oomycete plant pathogen Phytophthora infestans. In this manner, we demonstrate importin‐α‐dependent nuclear import of Nuk6 and Nuk7. In contrast, the nuclear import of Nuk12 and AtFib1 was unaffected in cells of NbImpα‐silenced plants. These data suggest that P. infestans Nuk6 and Nuk7 proteins are dependent on one or more α‐importins for nuclear import. Our VIGS‐based assay represents a powerful new technique to study mechanisms underlying the transport of proteins from cytoplasm to nucleus in plants.
Detection and identification of rhamnogalacturonan lyase activity in intercellular spaces of expanding cotton cotyledons
Authors: Naran Radnaa , Pierce Margaret L. , Mort Andrew J.
Published: March 2007

Rhamnogalacturonan lyase (RG lyase) activity has been detected and its relative activity measured in vivo during the expansion of cotton (Gossypium hirsutum L.) cotyledons. Rhamnogalacturonan (RG) oligomers labeled with a fluorescent tag were injected into the intercellular spaces of cotton cotyledons and, after incubation, the digested substrate was rinsed out. Enzyme digestion products were detected and identified by capillary zone electrophoresis. Rhamnogalacturonan lyase products were identified as such by co‐migration with the digestion products of linear RG oligomers when the oligomers were treated with fungal RG lyase but not when treated with fungal RG hydrolase. In addition, reaction of plant RG lyase digestion products of RG oligomers with I2/KI, which selectively removes unsaturated galactopyranosyluronic acid (GaLap) residues formed at the non‐reducing end of the oligomer, converted the plant digestion products into RG oligomers that co‐migrated with fungal RG hydrolase products. The activity of the enzyme in the intercellular spaces of cotton cotyledons is very low and could be detected most easily when not >0.03 nmol of substrate was injected in a ∼0.7‐cm2 area and incubated in vivo for 2–6 h. Rhamnogalacturonan lyase activity was the highest in rapidly expanding 3‐ to 4‐day‐old cotyledons and gradually decreased during the slow‐down in expansion over the next 2–3 days. The RG lyase activity was also detected when the APTS (8‐aminopyrene‐1,3,6‐trisulfonic acid, trisodium salt)‐labeled substrates were introduced into intercellular spaces by infiltration instead of injection, indicating that the activity was not induced by wounding or released into the apoplast by cell damage. An exo‐RG galacturonohydrolase activity was also found, but RG hydrolase and exo‐RG rhamnohydrolase were not detected.
Phytochrome A is an irradiance‐dependent red light sensor
Authors: Franklin Keara A. , Allen Trudie , Whitelam Garry C.
Published: March 2007

Plants perceive red (R) and far‐red (FR) light signals using the phytochrome family of photoreceptors. In Arabidopsis thaliana, five phytochromes (phyA–phyE) have been identified and characterized. Unlike other family members, phyA is subject to rapid light‐induced proteolytic degradation and so accumulates to relatively high levels in dark‐grown seedlings. The insensitivity of phyA mutant seedlings to prolonged FR and wild‐type appearance in R has led to suggestions that phyA functions predominantly as an FR sensor during the early stages of seedling establishment. The majority of published photomorphogenesis experiments have, however, used <50 µmol m−2 sec−1 of R when characterizing phytochrome functions. Here we reveal considerable phyA activity in R at higher (>160 µmol m−2 sec−1) photon irradiances. Under these conditions, plant architecture was observed to be largely regulated by the redundant actions of phytochromes A, B and D. Moreover, quadruple phyBphyCphyDphyE mutants containing only functional phyA displayed R‐mediated de‐etiolation and survived to flowering. The enhanced activity of phyA in continuous R (Rc) of high photon irradiance correlates with retarded degradation of the endogenous protein in wild‐type plants and prolonged epifluorescence of nuclear‐localized phyA:YFP in transgenic lines. Such observations suggest irradiance‐dependent ‘photoprotection’ of nuclear phyA in R, providing a possible explanation for the increased activity observed. The discovery that phyA can function as an effective irradiance sensor, even in light environments that establish a high Pfr concentration, raises the possibility that phyA may contribute significantly to the regulation of growth and development in daylight‐grown plants.
Long‐distance dispersal and local retention of larvae as mechanisms of recruitment in an island population of a coral reef fish
Authors: PATTERSON HEATHER M. , SWEARER STEPHEN E.
Published: March 2007

Abstract  Although recruitment of pelagic larvae is a fundamental and well‐documented process in the dynamics of benthic marine populations, identifying the sources of recruitment, or the degree to which populations are connected via dispersal of larvae, has remained elusive for most marine taxa. In this study we used natural environmental markers (trace elements) recorded in fish otoliths (ear stones) as tags of natal origin. Specifically, we used the otolith core and edge chemistries of a locally endemic wrasse (Coris bulbifrons) from Lord Howe Island (LHI), Australia, and a widely distributed species (Coris picta) from three potential mainland source regions, to determine the likely sources of recruitment to C. picta populations on LHI. The use of a local endemic species, which is by definition self‐recruiting, is a novel approach for ground‐truthing the dispersal history of non‐endemic coral reef fish. Discriminant function analyses were able to separate LHI from mainland fish, using both edge and core signatures, with a high degree of accuracy, suggesting at least some of the C. picta collected on LHI were of local origin. This result was corroborated when half of the C. bulbifrons and LHI C. picta were introduced as unknowns into a discriminant function analysis using the remaining C. bulbifrons, LHI C. picta, and the mainland C. picta as a training data set. Overall, our findings suggest that both long distance dispersal and local retention are important sources of recruitment to populations of C. picta on LHI and that otolith chemistry of endemic species could be a useful benchmark for determining the prevalence of self‐recruitment in insular populations of other widespread species.
What limits a rare alpine plant species? Comparative demography of three endemic species of Myosotis (Boraginaceae)
Authors: DICKINSON KATHARINE J. M. , KELLY DAVE , MARK ALAN F. , WELLS GUDRUN , CLAYTON RICHARD
Published: March 2007

Abstract  Establishing what are the underlying causes of species range limits is of fundamental interest in ecology. We followed the fate of individually mapped plants of three endemic New Zealand high‐alpine species of Myosotis, over a period of 9 years. The species provide contrasts in their geographical range and their demography. Myosotis oreophila Petrie is rare and extremely localized (c. 0.5 ha extent), Myosotis cheesemanii Petrie is regionally endemic, and Myosotis pulvinaris Hook. f. is more widespread. All three occur on the Dunstan Mountains, Central Otago, South Island, New Zealand within a 1‐km radius, and individual plants were followed in four permanent plots. The three species differed in their longevity and in population variability, with the most widespread species (M. pulvinaris) having the lowest survival (61% per year), the fewest old plants (only 3% of plants present in 1993 surviving until 2001), no increase in survival rates with age, and the most variability in total numbers across years. Both of the rare species, M. oreophila and M. cheesemanii, had higher survival (75% and 88%, respectively, per year) especially for older plants, many older plants (20% and 59%, respectively, of 1993 plants surviving until 2001), and lower variability in total numbers across years. These results are consistent with other studies showing that rare plant species tend to have higher inertia than more common congeners. The range limits of M. oreophila showed a high level of spatial constancy on a scale of metres over the 9 years, despite 80% turnover in plants during that time. The M. oreophila population showed lower mean densities of plants near to the population boundaries, identical age‐specific survival rates, but lower flowering probabilities, than the core of the population. We were unable to detect any abiotic differences between inside and outside the M. oreophila range in terms of topography, soil parent materials, microclimate or through manipulation of snow cover. Disturbance may be a factor affecting the distribution of M. cheesemanii but limiting factors for M. oreophila and M. pulvinaris are likely to be biotic (competition, seed limitation, dispersal capacity) and/or historic. Further experimentation is recommended.
Aquatic macrophytes diversity in lagoons of a tropical floodplain: The role of connectivity and water level
Authors: DOS SANTOS ANDERSON MEDEIROS , THOMAZ SIDINEI MAGELA
Published: March 2007

Abstract  The goal of this research is to evaluate how the assemblages of aquatic macrophytes in marginal floodplain habitats, with different degrees of connectivity to the main river, respond to water level fluctuations. Samples were carried out quarterly (May 2000 to March 2002) in seven lagoons of the Upper Paraná River floodplain (22°30′ and 22°45′‐S and 53°15′ and 53°30′‐W) with different degrees of connectivity (connected and disconnected to the main river). In each lagoon, a shore‐pelagic zone transect was marked and at every 2 m the depth and the cover of each aquatic macrophyte species were recorded (Domin‐Krajina scale) in a quadrat of 0.25 m2. A total of 29 aquatic macrophyte species and an unusual decrease in water level were recorded in August 2001. Drawdown had a negative impact on species richness, only in connected lagoons, which was shown by a positive relationship between depth and species number (r‐Spearman = 0.86; P < 0.01). Depth affected Beta diversity positively (r‐Spearman = 0.79; P < 0.05). Drawdown affected the connected and disconnected lagoons differently, which can be attributed to their different morphometry. In this period, ‘habitat contraction’ was higher on connected lagoons. Positive correlation between mean species number and depth, and between beta diversity and depth, are factors that support this affirmation. Indicator species analysis showed that for disconnected lagoons, Oxycaryum cubense (Cyperaceae), Polygonum meissnerianum (Polygonaceae) and P. ferrugineum, with indicator values (IndVal) of 53, 30 and 25%, respectively, were indicator species. Salvinia spp. (Salvinaceae) (62%), P. acuminatum (44%) and the Ricciaceae Ricciocarpus natans (0%) were the indicator species of the connected lagoons.
The neglect of spatial mobility in contemporary studies of work: the case of telework
Authors: Hislop Donald , Axtell Carolyn
Published: March 2007

Whilst many teleworkers are increasingly working beyond home and office, these mobile teleworkers are neglected in the telework literature. This neglect is addressed through reviewing relevant literature, developing a conceptual locational framework that accounts for mobile teleworkers and the presentation of an illustrative example which links to the theme of work–life balance in the telework literature.
A framework for analysing the microbiological commons
Authors: Hess Charlotte , Ostrom Elinor
Published: March 2007

In an earlier article, “Ideas, artifacts and facilities: information as a common‐pool resource”, we examined the role of collective action in building robust knowledge commons and in circumventing trends of enclosure and privatisation of the intellectual public domain. Our analysis suggested that collective action and new institutional design play as large a part in shaping the collection, distribution, and preservation of scholarly information as do legal restrictions and market forces. The microbiological commons extends well beyond the boundaries of e‐prints and other full‐text research documents that are the focus of the open access movement. It includes the contents of scientific databases, research archives, and multimedia publications which all need to be seamlessly integrated. In addition, the global, biological commons is also comprised of social networks and social capital. The success of freely sharing microbiological data will require a complex blend of technology, scientific content, metadata standards, open source software packages, negotiated and respected intellectual property rights agreements, sustainability and preservation design mechanisms, evolving rules and institutions, and, ultimately, a firm commitment on the part of providers and users to the common good.
Stigmatization experience, coping and sense of coherence in vitiligo patients
Authors: Schmid‐Ott G , Künsebeck H‐W , Jecht E , Shimshoni R , Lazaroff I , Schallmayer S , Calliess IT , Malewski P , Lamprecht F , Götz A
Published: March 2007

Objective  This study examines the extent of stigmatization experienced by vitiligo patients considering the visibility of the lesions.

Methods  363 vitiligo patients were assessed using the Experience with Skin Complaints (QES), Adjustment to Chronic Skin Disorders (ASC), and Sense of Coherence (SOC) questionnaires. Out of the total patients group two representative samples with 52 patients each were identified comparable for age, gender, and the duration of the skin disease, the first with visible and the second with invisible lesions.

Results  Data indicate a significant negative correlation between the QES dimensions, except for ‘Composure’, and between coping scales with sense of coherence withstanding. The ‘visible lesions’ group scored higher compared to the ‘invisible lesions’ group on the two QES scales ‘Self‐Esteem’ and ‘Refusal’, i.e., patients with visible lesions experienced a higher level of stigmatization.

Conclusion  This study provides new information which supports the notion that the stigmatization experience of vitiligo patients is psychologically relevant.
The effect of frame figure type and frame size on the line and the circle Ponzo illusions
Authors: YAMAGAMI AKIRA
Published: March 2007

Abstract:  To examine the determinants of the Ponzo illusion, we compared the perceived size of lines and circles presented within three different frames: two converging lines, two circles, and two squares. Twenty stimulus figures, consisting of two types of objects (lines/circles) × three types of frame figures (Ponzo/circles/squares) × three sizes of lower frames (small/medium/large), and two control figures were presented on a personal computer display. Twelve students performed three measurements (upper‐object/lower‐object/illusion) for each stimulus figure using the method of adjustment. To analyze the relationship between single object perception and the Ponzo illusion, we compared the calculated values of overestimation magnitude differences between the upper and lower objects with the actual obtained illusion values of the six object‐frame conditions. The calculated values of the circle and the square frame figures corresponded to the difference between the upper single object and the lower single object. In contrast, the results of the Ponzo figure need an additional factor to explain the differences between the obtained and the calculated values. These results indicate that two factors are involved in the Ponzo illusion: (a) the framing effect affects the perceived size of the individual single objects, and (b) the comparison factor affects the comparison process of the two objects within the converging lines.
Luminance differences between the figures and background are not necessary for parallel search of a Kanizsa illusory square1
Authors: TAKAHASHI SHIN’YA , OHYA KAZUO , ARAKAWA KEIKO , TANABE YURI
Published: March 2007

Abstract:  In order to examine the role of differences in luminance in the early visual processing of the Kanizsa illusion, two experiments employing a visual search task were conducted. In the first experiment, 18 participants detected the target (a configuration generating the Kanizsa illusory square) among a variable number of non‐targets in either a luminance difference (LD) condition or a color difference (CD) condition. In the CD condition, luminance of the green figures and red background were equalized. Participants detected the target as efficiently in the CD condition as in the LD condition, showing the “pop‐out” of the isoluminant Kanizsa illusion. In the second experiment, the possible effect of residual luminance differences in the CD condition was examined. Three participants performed the same visual search task as in Experiment 1 under two isoluminant conditions; one with the equalization of the CIE luminance as in Experiment 1, and the other with equalization by means of minimum flicker photometry. The results showed no difference between the search efficiency in the two conditions. Overall, these results are consistent with previous findings and support the view that the primary generating factor of the Kanizsa illusion is figural information, specifically the two figural cues of alignment and incompletion, not the luminance difference between the figures and the background.
Selective re‐routing of prion protein to proteasomes and alteration of its vesicular secretion prevent PrPSc formation
Authors: Filesi Ilaria , Cardinale Alessio , Mattei Sonia , Biocca Silvia
Published: March 2007

Conversion of the cellular prion protein (PrPC) into the abnormal scrapie isoform (PrPSc) is the hallmark of prion diseases, which are fatal and transmissible neurodegenerative disorders. ER‐retained anti‐prion recombinant single‐chain Fv fragments have been proved to be an effective tool for inhibition of PrPC trafficking to the cell surface and antagonize PrPSc formation and infectivity. In the present study, we have generated the secreted version of 8H4 intrabody (Sec‐8H4) in order to compel PrPC outside the cells. The stable expression of the Sec‐8H4 intrabodies induces proteasome degradation of endogenous prion protein but does not influence its glycosylation profile and maturation. Moreover, we found a dramatic diverting of PrPC traffic from its vesicular secretion and, most importantly, a total inhibition of PrPSc accumulation in NGF‐differentiated Sec‐8H4 PC12 cells. These results confirm that perturbing the intracellular traffic of endogenous PrPC is an effective strategy to inhibit PrPSc accumulation and provide convincing evidences for application of intracellular antibodies in prion diseases.
Rates of methanogenesis and methanotrophy in deep‐sea sediments
Authors: SIVAN O. , SCHRAG D. P. , MURRAY R. W.
Published: March 2007

We use the carbon isotopic composition (δ13C) of the dissolved inorganic carbon (DIC) of pore fluids from Leg 175 of the Ocean Drilling Program (ODP) along the West African Margin to quantify rates of methane production (methanogenesis) and destruction via oxidation (methanotrophy) in deep‐sea sediments. Results from a model of diffusion and reaction in the sedimentary column show that anaerobic methane oxidation (AOM) occurs in the transition zone between the presence of sulfate and methane, and methanogenesis occurs below these depths in a narrow confined zone that ends at about 250 m below the sea‐sediments surface in all sediment profiles. Our model suggests that the rates of methanogenesis and AOM range between 6 · 10−8 and 1 · 10−10 mol cm−3 year−1 at all sites, with higher rates at sites where sulfate is depleted in shallower depths. Our AOM rates agree with those based solely on sulfate concentration profiles, but are much lower than those calculated from experiments of sulfate reduction through AOM done under laboratory conditions. At sites where the total organic carbon (TOC) is less than 5% of the total sediment, we calculate that AOM is the main pathway for sulfate reduction. We calculate that higher rates of AOM are associated with increased recrystallization rates of carbonate minerals. We do not find a correlation between methanogenesis rates and the content of carbonate or TOC in the sediments, porosity, sedimentation rate, or the C:N ratio, and the cause of lack of methanogenesis below a certain depth is not clear. There does, however, appear to be an association between the rates of methanogenesis and the location of the site in the upwelling system, suggesting that some variable such as the type of the organic matter or the nature of the microbiological community may be important.
Treatment of facial reticular veins with dynamically cooled, variable spot‐sized 1064 nm Nd:YAG laser
Authors: Lai Stephanie W , Goldman Mitchel P
Published: March 2007

Background  Facial reticular veins are often seen on the temple and periorbital areas in patients with genetic predisposition or after facial cosmetic surgery.

Aim  The purpose of this study was to evaluate the efficacy and safety of dynamically cooled, variable spot sized 1064 nm Nd:YAG laser in the treatment of facial reticular veins.

Patients/methods  This is a retrospective study. Twenty patients with facial reticular veins who underwent treatment with dynamically cooled, variable spot sized 1064 nm Nd:YAG laser were evaluated. Patients were followed up 1 month to 2 years after the procedure.

Results  Objective and subjective improvement scores after one or two treatments of dynamically cooled, variable spot sized 1064 nm Nd:YAG laser were nearly 100% when appropriate parameters were used.

Conclusion  Dynamically cooled, variable spot sized 1064 nm Nd:YAG laser is a safe and effective treatment for facial reticular veins. Most patients responded to one treatment and experienced no significant side effects other than tolerable pain associated with the procedure.
In praise of blushing
Authors: Crozier W Ray
Published: March 2007

Many people are extremely anxious about their blushing and regard it as the cause of their social difficulties rather than as a symptom of them. This paper addresses the belief that there is something inherently unpleasant or unattractive about blushing. Historical evidence shows that redness of the cheeks has long been regarded as a sign of facial beauty and youth, and transitory changes such as the blush have also been seen in a positive light as an indication of modesty and charm. The blush is an expression of shame and embarrassment and it too can be regarded in positive or negative light depending on the circumstances. What is distinctive about contemporary anxieties about blushing is that perceived personal inadequacies are in themselves reason to be ashamed and embarrassed: there is a vicious circle where a blush is both a sign of, and reason for, self‐deprecation. This perception is not a necessary one but reflects current cultural values and this has implications for the treatment of blushing anxieties.
Prevalence of Peripheral Arterial Disease and Risk Factors in Persons Aged 60 and Older: Data from the National Health and Nutrition Examination Survey 1999–2004
Authors: Ostchega Yechiam , Paulose‐Ram Ryne , Dillon Charles F. , Gu Qiuping , Hughes Jeffery P.
Published: March 2007

OBJECTIVES: Peripheral arterial disease (PAD) is associated with significant cardiovascular morbidity and mortality. The study objectives were to examine the prevalence of PAD and associated risk factors.

DESIGN: A cross‐sectional nationally representative health examination survey.

SETTING: The National Health and Nutrition Examination Survey 1999–2004.

PARTICIPANTS: Data from 3,947 men and women aged 60 and older who received a lower extremity examination.

MEASUREMENTS: The main outcome was PAD, defined as an ankle‐brachial blood pressure index of less than 0.9 in either leg.

RESULTS: In older U.S. adults, PAD prevalence was 12.2% (95% confidence interval (CI) = 10.9–13.5%). PAD prevalence increased with age. PAD prevalence was 7.0% (95% CI = 5.6–8.4%) for those aged 60 to 69, 12.5% (95% CI = 10.4–14.6%), and 23.2% (95% CI = 19.8–26.7%) for those aged 70 to 79 and 80 and older. Age‐adjusted estimates show that non‐Hispanic black men and women and Mexican‐American women had a higher prevalence of PAD than non‐Hispanic white men and women (19.2%, 95% CI = 13.7–24.6%; 19.3%, 95% CI = 13.3–25.2%; and 15.6%, 95% CI = 12.7–18.6%, respectively). The results of the fully adjusted model show that current smoking (OR = 5.48, 95% CI = 3.60–8.35), previous smoking (OR = 1.94, 95% CI = 1.39–2.69), diabetes mellitus (OR = 1.81, 95% CI = 1.12–2.91), low kidney function (OR = 2.69, 95% CI = 1.58–4.56), mildly decreased kidney function (OR = 1.71, 95% CI = 1.22–2.38), high‐sensitivity C‐reactive protein greater than 3.0 mg/L (OR = 2.69, 95% CI = 1.24–5.85), treated but not controlled hypertension (OR = 1.95, 95% CI = 1.40–2.72), and untreated hypertension (OR = 1.68, 95% CI = 1.13–2.50) were all significantly associated with prevalent PAD.

CONCLUSION: PAD prevalence increases with age and is associated with treatable risk factors for cardiovascular disease.
Peer‐Perceived Admiration and Social Preference: Contextual Correlates of Positive Peer Regard Among Suburban and Urban Adolescents
Authors: Becker Bronwyn E. , Luthar Suniya S.
Published: March 2007

The primary purpose of this study was to understand further the heterogeneity of popularity, by exploring contextual correlates of two dimensions of positive peer regard among seventh graders within two highly disparate sociodemographic groups: affluent suburban and low‐income urban (N=636). Three sets of attributes were examined, all consistently linked to social status in past research: rebellious behaviors (aggression, academic disengagement, delinquency, and substance use), academic application (effort at school and good grades), and physical attributes (attractiveness and athletic ability). The data provide empirical validation for the conceptual distinctions among peer‐perceived admiration and social preference with adolescents from diverse contexts. More specifically, results showed that within each socioeconomic context (a) some forms of rebellious behaviors are clearly admired, (b) prosocial attributes are linked with peer‐perceived admiration and social preference, (c) physical attractiveness and athletic skills are important for positive peer regard, the former particularly for suburban girls and the latter for suburban boys, and (d) aggression elicits admiration among early adolescents, but can also generate their disdain (i.e., lowered social preference). In the urban context, results provided evidence for the salience of distinct forms of rebellious and achievement oriented behaviors among different racial/ethnic groups as well.
Sexual Partners and Contraceptive Use: A 16‐Year Prospective Study Predicting Abstinence and Risk Behavior
Authors: Siebenbruner Jessica , Zimmer‐Gembeck Melanie J. , Egeland Byron
Published: March 2007

Antecedents and correlates of sexual behavior among 167 (46% female) adolescents were examined in this multi‐informant longitudinal study. Data were collected at birth through middle adolescence. Data on number of sexual partners and contraception use at age 16 defined sexual abstinence (SAs, n=73), high‐risk sexual behavior (HRTs, n=45) and low‐risk sexual behavior (LRTs, n=49) groups. Moffitt's (1993) antisocial behavior taxonomy, problem behavior theory (Jessor & Jessor, 1977), social control theory (Hierschi), and a biosocial model (Udry, 1988) guided expectations of differential group prediction. Variables from each of three developmental periods (<age 12, ages 12–13, age 16) were significantly associated with sexual behavior groups. The most salient factors that differentiated LRTs from SAs were physical maturation at age 13 and romantic relationship progression and alcohol use at age 16. Romantic relationship progression and drug use at age 16 differentiated HRTs from SAs.
Thermodynamic Effect on a Cavitating Inducer in Liquid Nitrogen
Authors: Yoshida Yoshiki , Kikuta Kengo , Hasegawa Satoshi , Shimagaki Mitsuru , Tokumasu Takashi
Published: March 2007

For experimental investigations of the thermodynamic effect on a cavitating inducer, it is nesessary to observe the cavitation. However, visualizations of the cavitation are not so easy in cryogenic flow. For this reason, we estimated the cavity region in liquid nitrogen based on measurements of the pressure fluctuation near the blade tip. In the present study, we focused on the length of the tip cavitation as a cavitation indicator. Comparison of the tip cavity length in liquid nitrogen (80K) with that in cold water (296K) allowed us to estimate the strength of the thermodynamic effect. The degree of thermodynamic effect was found to increase with an increase of the cavity length. The temperature depression was estimated from the difference of the cavitation number of corresponding cavity condition (i.e., cavity length) between in liquid nitrogen and in cold water. The estimated temperature depression caused by vaporization increased rapidly when the cavity length extended over the throat. In addition, the estimated temperature inside the bubble nearly reached the temperature of the triple point when the pump performance deteriorated.
Absolute dose measurements by means of a small cylindrical ionization chamber for very high dose per pulse high energy electron beams
Authors: Karaj E. , Righi S. , Di Martino F.
Published: March 2007

Very high dose per pulse high energy electron beams are currently produced by special linear accelerators (linac) dedicated to Intra Operative Radiation Therapy (IORT). The electron beams produced by such linacs are collimated by special Perspex applicators of various size and cylindrically shaped. The biggest problems from the dosimetric point of view are caused by the high dose‐per‐pulse values and the use of inclined applicators. In this work measurements of absolute dose for the inclined applicators were done by using a small cylindrical ionization chamber, type CC01 (Wellhofer), a parallel plane ionization chamber type Markus (PTW 23343) and radiochromic films type EBT. We show a method which allows calculating the quality correction factors for CC01 chamber with an uncertainty of 1% and the absolute dose value for the inclined applicators using CC01 with an uncertainty of 3.1% for electron beams of energy of 6 and produced by the linac dedicated to IORT Novac7.
X‐ray imaging using avalanche multiplication in amorphous selenium: Investigation of depth dependent avalanche noise
Authors: Hunt D. C. , Tanioka Kenkichi , Rowlands J. A.
Published: March 2007

The past decade has seen the swift development of the flat‐panel detector (FPD), also known as the active matrix flat‐panel imager, for digital radiography. This new technology is applicable to other modalities, such as fluoroscopy, which require the acquisition of multiple images, but could benefit from some improvements. In such applications where more than one image is acquired less radiation is available to form each image and amplifier noise becomes a serious problem. Avalanche multiplication in amorphous selenium can provide the necessary amplification prior to read out so as to reduce the effect of electronic noise of the FPD. However, in direct conversion detectors avalanche multiplication can lead to a new source of gain fluctuation noise called depth dependent avalanche noise. A theoretical model was developed to understand depth dependent avalanche noise. Experiments were performed on a direct imaging system implementing avalanche multiplication in a layer of to validate the theory. For parameters appropriate for a diagnostic imaging FPD for fluoroscopy the detective quantum efficiency (DQE) was found to drop by as much as 50% with increasing electric field, as predicted by the theoretical model. This drop in DQE can be eliminated by separating the collection and avalanche regions. For example by having a region of low electric field where x rays are absorbed and converted into charge that then drifts into a region of high electric field where the x‐ray generated charge undergoes avalanche multiplication. This means quantum noise limited direct conversion FPD for low exposure imaging techniques are a possibility.
Comparison of typical evaluation methods for computer‐aided diagnostic schemes: Monte Carlo simulation study
Authors: Li Qiang , Doi Kunio
Published: March 2007

Computer‐aided diagnostic (CAD) schemes have been developed for assisting radiologists in the detection of various lesions in medical images. Many evaluation approaches, such as the resubstitution, leave‐one‐out, cross‐validation, and hold‐out methods, have been employed for the assessment of the performance of various CAD schemes. For these evaluation methods, some investigators have studied their bias in the estimated performance levels of CAD schemes trained with finite samples. However, systematical study has not been conducted for the comparison of these common evaluation methods in terms of multiple important characteristics such as the bias of the estimated performance, the generalization performance, and the uniqueness of the trained CAD scheme. Therefore, in this study, we examined and compared these important characteristics for various evaluation methods and attempted to provide a guideline for investigators to select appropriate evaluation methods for the assessment of CAD schemes in typical practical situations.