bluuebunny/crossref_metadata_2025 huggingface dataset:
Metal Objects Mapping After Small Charge Explosions. A Study on AISI 304Cu Steel with Two Different Grain Sizes
Authors: Firrao Donato , Matteis Paolo , Scavino Giorgio , Ubertalli Graziano , Ienco Maria G. , Pellati Gabriella , Piccardo Paolo , Pinasco Maria R. , Stagno Enrica , Costanza Girolamo , Montanari Roberto , Tata Maria E. , Brandimarte Giovanni , Petralia Santo
Published: April 2006

ABSTRACT: Evidence of exposure of a metal component to a small charge explosion can be detected by observing microstructural modifications; they may be present even if the piece does not show noticeable overall plastic deformations. Particularly, if an austenitic stainless steel (or another metal having a face‐centered cubic structure and a low stacking fault energy) is exposed to an explosive shock wave, high‐speed deformation induces primarily mechanical twinning, whereas, in nonexplosive events, a lower velocity plastic deformation first induces slip. The occurrence of mechanical twins can be detected even if the surface is damaged or oxidized in successive events. In the present research, optical metallography (OM) and scanning electron microscopy (SEM), and scanning tunneling microscopy (STM) were used to detect microstructural modifications caused on AISI 304Cu steel disks by small‐charge explosions. Spherical charges of 54.5 or 109 g TNT equivalent mass were used at explosive‐to‐target distances from 6.5 to 81.5 cm, achieving peak pressures from 160 to 0.5 MPa. Explosions induced limited or no macro‐deformation. Two alloy grain sizes were tested. Surface OM and SEM evidenced partial surface melting, zones with recrystallization phenomena, and intense mechanical twinning, which was also detected by STM and X‐ray diffraction. In the samples' interior, only twins were seen, up to some distance from the explosion impinged surface and again, at the shortest charge‐to‐sample distances, in a thin layer around the reflecting surface. For forensic science locating purposes after explosions, the maximum charge‐to‐target distance at which the phenomena disappear was singled out for each charge or grain size and related to the critical resolved shear stress for twinning.
Composition of Bacillus Species in Aerosols from 11 U.S. Cities
Authors: Merrill Lori , Dunbar John , Richardson Jennifer , Kuske Cheryl R.
Published: April 2006

ABSTRACT: A PCR‐based heteroduplex assay was used to determine the presence and composition of Bacillus species in 11,059 Environmental Protection Agency PM2.5 aerosol samples from 11 U.S. cities. The assay differentiated three groups: Type A containing Bacillus anthracis and very closely related, often pathogenic, Bacillus cereus and Bacillus thuringiensis strains; Type B containing other B. cereus and B. thuringiensis strains; and a third group of more‐distantly related Bacillus species. Eight of the 11 cities were positive for Bacillus species in 50% or more of the samples, and the percent of aerosol samples that contained the HD Type A group ranged from 3% to 32%. Cities from the eastern half of the United States generally contained a higher frequency and broader diversity of Bacillus species than the western half of the United States. Positive samples were detected throughout the year. These results have implications for pathogen detection in environmental samples, understanding the natural evolution of new pathogenic strains, and incidence of infection caused by strains of the B. cereus subgroup.
Use of Diagonal Teeth Measurements in Predicting Gender in a Turkish Population*
Authors: Karaman Feryal
Published: April 2006

ABSTRACT: Mesiodistal and buccolingual measurements, commonly used as a means of sex determination from teeth, can sometimes cause difficulties. The aim of this study is to test whether diagonal measurements can make it possible to take more accurate measurements. The results of diagonal measurements of dental casts taken from 30 males and 30 females have been evaluated by discriminant function statistics. Intra‐ and interobserver error tests did not indicate any statistically significant differences between the findings of two observers. Seven of the 14 measurements on the maxilla and 10 of the 14 measurements on the mandible have been found to be significantly greater in males. According to the results of the stepwise discriminant function statistics, the most contributory measurements to the function were upper first incisor mesiobuccal–distolingual (MBDL) and distobuccal–mesiolingual, lower second incisor MBDL, and lower canine MBDL. The highest reliability was obtained in MBDL measurements. It was realized that diagonal measurements of teeth, especially of canines, revealed clear dimorphic differences. Classification accuracy was found to be 83.3% for total sample, 78.3 for upper jaw, and 85.0% for the lower jaw. Accuracy rate was higher in the lower teeth. Commonly seen orthodontic anomalies, such as tooth rotations, crowding, attritions, deep dentin–enamel junction defects, and certain types of fillings, could make it difficult to correctly take width measurements or could cause other mistakes to occur. This explains the reason why this research has been considered to be of some use in diagonal measurements, which is an accurate method, particularly when employed for the front teeth.
CAP MTR versus environmentally targeted agricultural policy in marginal arable areas: impact analysis combining simulation and survey data
Authors: Muñiz Ignacio Atance , Hurlé Jesús Barreiro
Published: April 2006

On June 2003 the final version of the Common Agricultural Policy Mid‐Term Review (CAP MTR) was published. The driving forces of this policy change include inter alia the compliance with World Trade Organization (WTO) negotiations' requirements, improvement of social support for agricultural policy, adjustment to budget constraints and adaptation of agricultural practices to environmental requirements. This article reviews how this policy performs in marginal areas regarding one of those objectives: the provision of environmental outputs related to agricultural activity. As an alternative to this reform, a policy based on agri‐environmental measures designed to maximize environmental outputs, is proposed. Both options are evaluated from a cost‐effectiveness point of view. Data from a farm survey and a positive mathematical programming model for a cereal steppes agro‐system in Spain are combined in order to simulate the effects of this reform and our alternative instrument on several environmental indicators. Results show that in marginal areas, where land abandonment is a clear threat, more environmental output can be achieved for the same cost, while maintaining, if not increasing, the levels of achievement for the other goals.
Procoagulant factors and the risk of myocardial infarction in young women
Authors: Tanis Bea , Algra Ale , Van Der Graaf Yolanda , Helmerhorst Frans , Rosendaal Frits
Published: April 2006

Abstract:  Objectives: We investigated whether elevated levels of factor VIII, IX and XI is associated with myocardial infarction (MI) in young women. In addition, we studied ABO blood group, von Willebrand factor (VWF) and C‐reactive protein (CRP). Methods and results: We compared 200 women with MI before age 49 years with 626 controls from a population‐based case–control study. Mean levels of factor VIII activity (VIII), von Willebrand factor antigen (VWF), factor IX activity (IX) were higher in patients (133, 134 and 132 IU/dL) than in controls (111, 107 and 120 IU/dL, respectively). Mean levels of factor XI (XI) were equal in patients (114 IU/dL) and controls (113 IU/dL). The odds ratio (OR) for MI for blood group non‐O vs. O was 1.6 [95% confidence interval (CI) 1.1–2.3]. The OR adjusted for age, index year and area of residence for the highest quartile >150 IU/dL of factor VIII was 2.7 (95% CI 1.6–4.6), of VWF 4.7 (95% CI 2.3–9.7), of factor IX 2.6 (95% CI 1.3–5.4) and of factor XI 0.9 (95% CI 0.5–1.4), all compared with the lowest quartile <100 IU/dL. Conclusions: Non‐O blood group, high VWF, factor VIII and factor IX levels are associated with an increased risk of MI in young women, while high factor XI levels are not.
The High‐Affinity Immunoglobulin‐E Receptor (FceRI) is Endocytosed by an AP‐2/Clathrin‐Independent, Dynamin‐Dependent Mechanism
Authors: Fattakhova Gul'nar , Masilamani Madhan , Borrego Francisco , Gilfillan Alasdair M. , Metcalfe Dean D. , Coligan John E.
Published: April 2006

Aggregation of the high‐affinity immunoglobulin E (IgE) receptor (FcɛRI), expressed on mast cells and basophils, initiates the immediate hypersensitivity reaction. Aggregated FcɛRI has been reported to rapidly migrate to lipid rafts in RBL‐2H3 cells. We confirmed that aggregated FcɛRI is found in the lipid raft fractions of cellular lysates. Furthermore, we show that the cross‐linked FcɛRI remains associated with detergent‐resistant structures upon internalization. Previous morphological studies have reported that aggregated FcɛRI is endocytosed via clathrin‐coated pits, which in general are not lipid raft associated. To address this apparent discrepancy, we employed siRNA to suppress expression of components of the clathrin‐mediated internalization machinery, namely, clathrin heavy chain, and the AP‐2 (α‐adaptin or µ2‐subunit). Transferrin receptor (TfR) is endocytosed by a clathrin‐mediated process and, as expected, each transfected siRNA caused a two to threefold elevation of TfR surface expression and almost completely inhibited its endocytosis. In contrast, there was no effect on surface expression levels of FcɛRI nor on the endocytosis of the dinitrophenyl‐human serum albumin (DNP‐HSA)/IgE/FcɛRI complex. On the contrary, internalization of DNP‐HSA/IgE/FcɛRI was inhibited by overexpression of a dominant‐negative dynamin mutant. We conclude that internalization of cross‐linked FcɛRI does not require the AP‐2/clathrin complex but is dynamin‐dependent and may be lipid raft mediated.
ANALYSIS OF RESERVES DISCOVERED IN PETROLEUM EXPLORATION
Authors: Quirk D. G. , Ruthrauff R.
Published: April 2006

Mathematical theory and empirical data show that discovery sizes from mature plays have lognormal distributions. This allows a simple transformation to be used that converts lognormal trends to straight lines from which valuable statistical data on exploration potential is derived.

After correcting for the unreliable nature of data from non‐commercial accumulations and then discounting the extreme high ends and low ends (P1), discovery size distributions from a variety of mature plays outside the Middle East show certain common properties that help constrain reserves ranges in individual prospects and new play fairways. These are:

P99 is 0.3MM brl or less in non‐DHI oil plays and 4BCF or less in gas plays at normal depths;

P50 reserves fall within the range 7‐35 MM brl or 15–150 BCF (half of all discoveries are smaller than this);

risked average discovery size is generally 10‐100 MM brl or 20–200 BCF;

there is somewhere between a 1 in 5 and 1 in 4 chance of finding reserves equal to or larger than the average size of discovery;

the average minimum economic field size falls between P70 and P30, meaning that around half of all discoveries are too small to be commercial, except in onshore areas close to infrastructure;

P90 values show the smallest variation over time as a play matures but these rarely become commercial;

most established conventional plays contain 1–10 billion brl o.e. of recoverable resource.

In contrast, upside reserves, the number of discoveries and the chance of making a discovery are unique to each play. Also, rather than indicating the exploration maturity of a play per se, P10/P90 ratios reflect play specific limits to discovery size, although it is true that the P10/P90 ratio decreases as the number of discoveries increases.

As most large discoveries are made in emergent plays, companies looking for high impact (unusually large) prospects are unlikely to find these in established plays meaning that they need to be prepared to explore at higher risk, often in frontier areas.
Trophic and non‐trophic pathways mediate apparent competition through post‐dispersal seed predation in a Patagonian mixed forest
Authors: Caccia Fernando D. , Chaneton Enrique J. , Kitzberger Thomas
Published: April 2006

Post‐dispersal predation can be a major source of seed loss in temperate forests. Little is known, however, about how predator‐mediated indirect interactions such as apparent competition alter survival patterns of canopy tree seeds. Understorey plants may enhance tree seed predation by providing sheltered habitat to granivores (non‐trophic pathway). In addition, occurrence of different tree seeds in mixed patches may lead to short‐term apparent competition between seed types, because of the granivores’ foraging response to changes in food patch quality (trophic pathway). We hypothesised that understorey bamboo cover and mixing of seed species in food patches would both increase tree seed predation in aNothofagus dombeyi−Austrocedrus chilensisforest in northern Patagonia, Argentina. Seed removal experiments were conducted for three consecutive years (2000–2002) differing in overall granivory rates. Seed patch encounter and seed removal rates were consistently higher for the larger and more nutritiousAustrocedrusseeds than for the smallerNothofagusseeds. Seed removal was greater beneath bamboo than in open areas. This apparent competition pathway was stronger in a low‐predation year (2000) than in high‐predation years (2001–2002), suggesting a shift in microhabitat use by rodents. Patch composition had a significant, though weaker, impact on seed survival across study years, whereas seed density per patch enhanced encounter rates but did not influence seed removal. Removal of the less‐preferredNothofagusseeds increased in the presence ofAustrocedrusseeds, but the reciprocal indirect effect was not observed. However, this non‐reciprocal apparent competition between seed species was only significant in the high‐predation years. Our study shows that granivore‐mediated indirect effects can arise through different interaction pathways, affecting seed survival patterns according to the predator's preference for alternative seed types. Moreover, results indicate that the occurrence and relative strength of trophic vs non‐trophic pathways of apparent competition may change under contrasting predation scenarios.
Costs of parasite resistance for female survival and parental care in a freshwater isopod
Authors: Hasu Tiina , Tellervo Valtonen E. , Jokela Jukka
Published: April 2006

Parasite resistance is expected to be costly because activation and maintenance of immune system requires energy that will not be available for other fitness related functions. Here, we experimentally exposed gravid female isopods from two lake populations to trophically transmitted acanthocephalan parasite. Successful establishment of the parasite requires penetration to body cavity; therefore, it is likely to induce an immune response. Resistant females from a lake where the parasite occurs as well as from a lake without the parasite experienced higher mortality than susceptible or control females. Parasite exposure reduced the offspring size at birth in both susceptible, but especially, in resistant females, suggesting that resistant females had less resource to direct for parental care. Parasite exposure had no effect on brood dumping, time to release of offspring or offspring growth rate after birth. Hence, our results reveal costs of resistance in parental survival and parental care of offspring.
Effect of short‐term starvation versus high‐fat diet on intramyocellular triglyceride accumulation and insulin resistance in physically fit men
Authors: Johnson Nathan A. , Stannard Stephen R. , Rowlands David S. , Chapman Phillip G. , Thompson Campbell H. , O'Connor Helen , Sachinwalla Toos , Thompson Martin W.
Published: April 2006

It is currently believed that intramyocellular triglyceride (IMTG) accumulation and insulin resistance are a consequence of dietary fat ingestion and/or the elevated circulating lipid levels associated with chronic fat surplus. The purpose of this study was to compare the effect of short‐term starvation versus low‐carbohydrate (CHO)/high‐fat diet on IMTG accumulation and the development of insulin resistance in physically fit men. Intramyocellular triglyceride content, measured as intramyocellular lipid (IMCL) by proton magnetic resonance spectroscopy (1H‐MRS), and glucose tolerance/insulin sensitivity, assessed by frequently sampled intravenous glucose tolerance test (IVGTT), were determined after 67 h of: (a) water‐only starvation (S); and (b) very low‐CHO/high‐fat diet (LC). These diets had in common significant restriction of CHO availability but large differences in fat content. All results were compared with those measured after a mixed CHO diet (C). Dietary interventions were administered by cross‐over design. The level of dietary‐induced IMTG accumulation (P= 0.46), insulin resistance (P= 0.27) and glucose intolerance (P= 0.29) was not different between S and LC treatments. Intramyocellular triglyceride content and insulin sensitivity were negatively correlated (r=−0.63, P < 0.01). Therefore, whilst insulin resistance may be due to fat accumulation at a cellular level, in the integrated human organism this outcome is not exclusively a function of dietary fat intake. The comparable level of IMTG accumulation and insulin resistance following S and LC may suggest that these metabolic perturbations are largely a consequence of the increased lipolytic response associated with CHO restriction.
Molecular interactions between dipeptides, drugs and the human intestinal H+–oligopeptide cotransporter hPEPT1
Authors: Sala‐Rabanal Monica , Loo Donald D. F. , Hirayama Bruce A. , Turk Eric , Wright Ernest M.
Published: April 2006

The human intestinal proton‐coupled oligopeptide transporter hPEPT1 has been implicated in the absorption of pharmacologically active compounds. We have investigated the interactions between a comprehensive selection of drugs, and wild‐type and variant hPEPT1s expressed in Xenopus oocytes, using radiotracer uptake and electrophysiological methods. The β‐lactam antibiotics ampicillin, amoxicillin, cephalexin and cefadroxil, the antineoplastics δ‐aminolevulinic acid (δ‐ALA) and bestatin, and the neuropeptide N‐acetyl‐Asp‐Glu (NAAG), were transported, as judged by their ability to evoke inward currents. When the drugs were added in the presence of the typical substrate glycylsarcosine (Gly‐Sar), the inward currents were equal or less than that induced by Gly‐Sar alone. This suggests that the drugs are transported at a lower turnover rate than Gly‐Sar, but may also point towards complex interactions between dipeptides, drugs and the transporter. Gly‐Sar and the drugs also modified the kinetics of hPEPT1 presteady‐state charge movement, by causing a reduction in maximum charge (Qmax) and a shift of the midpoint voltage (V0.5) to more negative potentials. Our results indicate that the substrate selectivity of hPEPT1 is: Gly‐Sar > NAAG, δ‐ALA, bestatin > cefadroxil, cephalexin > ampicillin, amoxicillin. Based on steady‐state and presteady‐state analysis of Gly‐Sar and cefadroxil transport, we proposed an extension of the 6‐state kinetic model for hPEPT1 function that globally accounts for the observed presteady‐state and steady‐state kinetics of neutral dipeptide and drug transport. Our model suggests that, under saturating conditions, the rate‐limiting step of the hPEPT1 transport cycle is the reorientation of the empty carrier within the membrane. Variations in rates of drug cotransport are predicted to be due to differences in affinity and turnover rate. Oral availability of drugs may be reduced in the presence of physiological concentrations of dietary dipeptides in the gut, suggesting that oral delivery drugs should be taken on an empty stomach. The common hPEPT1 single‐nucleotide polymorphisms Ser117Asn and Gly419Ala retained the essential kinetic and drug recognition characteristics of the wild type, suggesting that neither variant is likely to have a major impact on oral absorption of drugs.
Calmodulin kinase II accelerates L‐type Ca2+ current recovery from inactivation and compensates for the direct inhibitory effect of [Ca2+]i in rat ventricular myocytes
Authors: Guo Jiqing , Duff Henry J.
Published: April 2006

Some studies report that the positive relationship between L‐type Ca2+ current (ICa−L) and frequency in cardiac myocytes is mainly due to a direct negative feedback of sarcoplasmic reticulum Ca2+ release on ICa−L inactivation while others provide evidence for activation of calmodulin kinase II (CaMKII). To further elucidate the role of endogenous CaMKII activity, the CaMKII inhibitory peptides, autocamtide‐2 relating inhibitory peptide (AIP) and myristoylated AIP were applied using conventional and perforated patch‐clamp methods. AIP inhibited the normal adaptive increase in ICa−L in response to abrupt increase in pacing frequency from 0.05 to 2 Hz. The positive ICa−L–frequency relationship was reversed by AIP and the inhibitory effect of AIP was significantly exaggerated at fast pacing rates. The onset of inactivation of ICa−L was not altered by AIP. After thapsigargin treatment, AIP slowed recovery from inactivation of ICa−L and this effect was exaggerated during fast pacing. Buffering of [Ca2+]i by BAPTA and EGTA accelerated recovery of ICa−L from inactivation, and BAPTA partly eliminated the effect of AIP on the recovery. We conclude that: (1) [Ca2+]i directly slows ICa−L recovery from inactivation; and (2) Ca2+‐dependent endogenous CaMKII activity accelerates the ICa−L recovery. Thus, at fast heart rates, elevated [Ca2+]i activates endogenous CaMKII and compensates for its direct inhibitory effect on ICa−L recovery from inactivation. Dynamic activity of endogenous CaMKII enhances the positive ICa−L–frequency relationship.
Effects of Geometry on Brush Seal Pressure and Flow Fields—Part II: Backing Plate Configurations
Authors: Dogu Yahya , Aksit Mahmut F.
Published: April 2006

Brush seal dynamic behavior is strongly related to pressure and flow fields. Developments in brush seal design have led to geometric modifications to control flow field and consequent brush seal issues including blow-down, hang-up, and pressure stiffening. Some of the geometric enhancements have been found to have common use as backing plate modifications. Over the two decades of brush seal evolution, many backing plate configurations have been suggested in numerous patent disclosures. Even so, literature on the effects of geometric modifications on pressure and flow fields remains limited. This study numerically investigates brush seal pressure and flow fields for such common conceptual backing plate configurations as single and multiple grooves, with and without by-pass passages. The CFD analysis presented employs a bulk porous medium approach for the bristle pack. The effectiveness of various backing plate configurations outlining important flow features is discussed. Results indicate that backing plate configurations have a decisive role in shaping seal pressure fields. In general, it has been found that all cases having bypass configuration leak more. Moreover, the major portion of the seal leakage through fence height is fed from the backing plate cavity. The single backing plate groove forms a constant pressure behind the bristle pack. In contrast, multiple grooves form multiple constant pressure regions.
Large-Eddy Simulation of Unsteady Surface Pressure Over a Low-Pressure Turbine Blade due to Interactions of Passing Wakes and Inflexional Boundary Layer
Authors: Sarkar S. , Voke Peter R.
Published: April 2006

The unsteady pressure over the suction surface of a modern low-pressure (LP) turbine blade subjected to periodically passing wakes from a moving bar wake generator is described. The results presented are a part of detailed large-eddy simulation (LES) following earlier experiments over the T106 profile for a Reynolds number of 1.6×105 (based on the chord and exit velocity) and the cascade pitch to chord ratio of 0.8. The present LES uses coupled simulations of cylinder for wake, providing four-dimensional inflow conditions for successor simulations of wake interactions with the blade. The three-dimensional, time-dependent, incompressible Navier-Stokes equations in fully covariant form are solved with 2.4×106 grid points for the cascade and 3.05×106 grid points for the cylinder using a symmetry-preserving finite difference scheme of second-order spatial and temporal accuracy. A separation bubble on the suction surface of the blade was found to form under the steady state condition. Pressure fluctuations of large amplitude appear on the suction surface as the wake passes over the separation region. Enhanced receptivity of perturbations associated with the inflexional velocity profile is the cause of instability and coherent vortices appear over the rear half of the suction surface by the rollup of shear layer via Kelvin-Helmholtz (KH) mechanism. Once these vortices are formed, the steady-flow separation changes remarkably. These coherent structures embedded in the boundary layer amplify before breakdown while traveling downstream with a convective speed of about 37% of the local free-stream speed. The vortices play an important role in the generation of turbulence and thus to decide the transitional length, which becomes time dependent. The source of the pressure fluctuations on the rear part of the suction surface is also identified as the formation of these coherent structures. When compared with experiments, it reveals that LES is worth pursuing as an understanding of the eddy motions and interactions is of vital importance for the problem.
Measurement and Calculation of Turbine Cascade Endwall Pressure and Shear Stress
Authors: Holley Brian M. , Becz Sandor , Langston Lee S.
Published: April 2006

The complex three-dimensional fluid flow on the endwall in an axial flow turbine blade or vane passage has been extensively investigated and reported on in turbomachinery literature. The aerodynamic loss producing mechanisms associated with the endwall flow are still not fully understood or quantitatively predictable. To better quantify wall friction contributions to endwall aerodynamic loss, low Mach number wind tunnel measurement of skin friction coefficients have been made on one endwall of a large scale cascade of high pressure turbine airfoils, at engine operating Reynolds numbers. Concurrently, predictive calculations of the endwall flow shear stress have been made using a computational fluid dynamics (CFD) code. Use of the oil film interferometry skin friction technique is described and applied to the endwall, to measure local skin friction coefficients and shear stress directions on the endwall. These are correlated with previously reported measured local endwall pressure gradients. The experimental results are discussed and compared to the CFD calculations, to answer questions concerning endwall aerodynamic loss predictive ability.
Effects of Damping and Varying Contact Area at Blade-Disk Joints in Forced Response Analysis of Bladed Disk Assemblies
Authors: Petrov E. P. , Ewins D. J.
Published: April 2006

An approach is developed to analyze the multiharmonic forced response of large-scale finite element models of bladed disks taking account of the nonlinear forces acting at the contact interfaces of blade roots. Area contact interaction is modeled by area friction contact elements which allow for friction stresses under variable normal load, unilateral contacts, clearances, and interferences. Examples of application of the new approach to the analysis of root damping and forced response levels are given and numerical investigations of effects of contact conditions at root joints and excitation levels are explored for practical bladed disks.
Asymmetric Coevolutionary Networks Facilitate Biodiversity Maintenance
Authors: Bascompte Jordi , Jordano Pedro , Olesen Jens M.
Published: April 2006

The mutualistic interactions between plants and their pollinators or seed dispersers have played a major role in the maintenance of Earth's biodiversity. To investigate how coevolutionary interactions are shaped within species-rich communities, we characterized the architecture of an array of quantitative, mutualistic networks spanning a broad geographic range. These coevolutionary networks are highly asymmetric, so that if a plant species depends strongly on an animal species, the animal depends weakly on the plant. By using a simple dynamical model, we showed that asymmetries inherent in coevolutionary networks may enhance long-term coexistence and facilitate biodiversity maintenance.
Uncommon abdominal muscle injury in a tennis player: internal oblique strain: Figure 1
Authors: Maquirriain J , Ghisi J P
Published: April 2006

The case of a strain injury of the internal oblique abdominal muscle in a professional tennis player is presented. This uncommon lesion resulted from eccentric, unbalanced trunk rotation. Magnetic resonance imaging helped to confirm the diagnosis. Tennis specific core strengthening is crucial for rehabilitation and recurrence prevention.
TRIHEDRON COEFFICIENTS FOR $\mathcal{U}_{q}(\mathfrak{sl}(3,\mathbb{C}))$
Authors: KIM DONGSEOK
Published: April 2006

The classical 3j symbol can be obtained from the representation theory of [Formula: see text]. It can be generalized to [Formula: see text] using web spaces. We find its general shape and some trihedron coefficients of the representation theory of [Formula: see text].
Phosphorylated HSP27 modulates the association of phosphorylated caldesmon with tropomyosin in colonic smooth muscle
Authors: Somara Sita , Bitar Khalil N.
Published: April 2006

Thin-filament regulation of smooth muscle contraction involves phosphorylation, association, and dissociation of contractile proteins in response to agonist stimulation. Phosphorylation of caldesmon weakens its association with actin leading to actomyosin interaction and contraction. Present data from colonic smooth muscle cells indicate that acetylcholine induced a significant association of caldesmon with PKCα and sustained phosphorylation of caldesmon at ser789. Furthermore, acetylcholine induced significant and sustained increase in the association of phospho-caldesmon with heat-shock protein (HSP)27 with concomitant increase in the dissociation of phospho-caldesmon from tropomyosin. At the thin filament level, HSP27 plays a crucial role in acetylcholine-induced association of contractile proteins. Present data from colonic smooth muscle cells transfected with non-phospho-HSP27 mutant cDNA indicate that the absence of phospho-HSP27 inhibits acetylcholine-induced caldesmon phosphorylation. Our results further indicate that the presence of phospho-HSP27 significantly enhances acetylcholine-induced sustained association of phospho-caldesmon with HSP27 with a concomitant increase in acetylcholine-induced dissociation of phospho-caldesmon from tropomyosin. We thus propose a model whereby upon acetylcholine-induced phosphorylation of caldesmon at ser789, the association of phospho-caldesmon (ser789) with phospho-HSP27 results in an essential conformational change leading to dissociation of phospho-caldesmon from tropomyosin. This leads to the sliding of tropomyosin on actin thus exposing the myosin binding sites on actin for actomyosin interaction.
Activation of central opioid receptors determines the timing of hypotension during acute hemorrhage-induced hypovolemia in conscious sheep
Authors: Frithiof R. , Rundgren M.
Published: April 2006

After an initial compensatory phase, hemorrhage reduces blood pressure due to a widespread reduction of sympathetic nerve activity (decompensatory phase). Here, we investigate the influence of intracerebroventricular naloxone (opioid-receptor antagonist) and morphine (opioid-receptor agonist) on the two phases of hemorrhage, central and peripheral hemodynamics, and release of vasopressin and renin in chronically instrumented conscious sheep. Adult ewes were bled (0.7 ml·kg−1·min−1) from a jugular vein until mean arterial blood pressure (MAP) reached 50 mmHg. Starting 30 min before and continuing until 60 min after hemorrhage, either artificial cerebrospinal fluid (aCSF), naloxone, or morphine was infused intracerebroventricularly. Naloxone (200 μg/min but not 20 or 2.0 μg/min) significantly increased the hemorrhage volume compared with aCSF (19.5 ± 3.2 vs. 13.9 ± 1.1 ml/kg). Naloxone also increased heart rate and cardiac index. Morphine (2.0 μg/min) increased femoral blood flow and decreased hemorrhage volume needed to reduce MAP to 50 mmHg (8.9 ± 1.5 vs. 13.9 ± 1.1 ml/kg). The effects of morphine were abolished by naloxone at 20 μg/min. It is concluded that the commencement of the decompensatory phase of hemorrhage in conscious sheep involves endogenous activation of central opioid receptors. The effective dose of morphine most likely activated μ-opioid receptors, but they appear not to have been responsible for initiating decompensation as 1) naloxone only inhibited an endogenous mechanism at a dose much higher than the effective dose of morphine, and 2) the effects of morphine were blocked by a dose of naloxone, which, by itself, did not delay the decompensatory phase.
Long-term facilitation of ventilation and genioglossus muscle activity is evident in the presence of elevated levels of carbon dioxide in awake humans
Authors: Harris Daniel P. , Balasubramaniam Arvind , Badr M. Safwan , Mateika Jason H.
Published: April 2006

We hypothesized that long-term facilitation (LTF) of minute ventilation and peak genioglossus muscle activity manifests itself in awake healthy humans when carbon dioxide is sustained at elevated levels. Eleven subjects completed two trials. During trial 1, baseline carbon dioxide levels were maintained during and after exposure to eight 4-min episodes of hypoxia. During trial 2, carbon dioxide was sustained 5 mmHg above baseline levels during exposure to episodic hypoxia. Seven subjects were exposed to sustained elevated levels of carbon dioxide in the absence of episodic hypoxia, which served as a control experiment. Minute ventilation was measured during trial 1, trial 2, and the control experiment. Peak genioglossus muscle activity was measured during trial 2. Minute ventilation during the recovery period of trial 1 was similar to baseline (9.3 ± 0.5 vs. 9.2 ± 0.7 l/min). Likewise, minute ventilation remained unchanged during the control experiment (beginning vs. end of control experiment, 14.4 ± 1.7 vs. 14.7 ± 1.4 l/min). In contrast, minute ventilation and peak genioglossus muscle activity during the recovery period of trial 2 was greater than baseline (minute ventilation: 28.4 ± 1.7 vs. 19.6 ± 1.0 l/min, P < 0.001; peak genioglossus activity: 1.6 ± 0.3 vs. 1.0 fraction of baseline, P < 0.001). We conclude that exposure to episodic hypoxia is necessary to induce LTF of minute ventilation and peak genioglossus muscle activity and that LTF is only evident in awake humans in the presence of sustained elevated levels of carbon dioxide.
Pseudoclosure of Anterior Fontanelle by Wormian Bone in Isolated Sagittal Craniosynostosis
Authors: Agrawal Deepak , Steinbok Paul , Cochrane D. Douglas
Published: April 2006

Aims and Objectives: Although syndromic craniosynostosis is one of the causes for early closure of the anterior fontanelle, there is no literature on the incidence and causes of fontanelle closure in isolated single-suture craniosynostosis. The objective of this study was to review the incidence of fontanelle closure by a wormian bone in isolated, nonsyndromic sagittal craniosynostosis. Materials and Methods: Intraoperative records of 100 consecutive children under 1 year of age, operated for isolated sagittal synostosis over a 14-year period (1987– 2000), were reviewed to identify the presence of a wormian bone closing the anterior fontanelle. Results: The median age at surgery was 4.2 months with a range of 1.9–11.7 months. Intraoperatively, a wormian bone was seen replacing the anterior fontanelle in 4 cases giving an incidence of 4%. Conclusions: A wormian bone can occupy the anterior fontanelle in children with isolated sagittal craniosynostosis giving the appearance of a ‘closed fontanelle’.
A Case of Sotos Syndrome with Subduroperitoneal Shunt
Authors: Park Seoung Woo , Park Moon Sung , Hwang Jin Soon , Shin Yong Sam , Yoon Soo Han
Published: April 2006

The authors present a case of Sotos syndrome with increasing severity of subdural hygroma from the age of 5 months, which was managed with a subduroperitoneal shunt at 10 months of age. The patient had been followed up until 30 months of age with continuing improvement of symptoms. The patient initially presented with dolichocephaly accompanied by macrocrania, early tooth development, repeated pneumonia infections and developmental retardation concerning crawling, sitting, walking and speaking at 5 months of age. Magnetic resonance imaging (MRI) demonstrated partial hypoplasia of the corpus callosum and bifrontal subdural hygroma. The patient underwent subduroperitoneal shunting at 10 months of age with partial improvement of symptoms. At 18 months of age, the patient showed increased irritability and sweating, and development of spinal kyphosis, which resulted from shunt malfunction as shown in the shuntogram. The appearance of cervical syringomyelia was also seen in the MRI. After shunt revision, the irritability, sweating and kyphosis improved along with disappearance of the syringomyelia. The authors describe a case of Sotos syndrome with subduroperitoneal shunt that showed syringomyelia which developed with shunt malfunction but disappeared after shunt revision. We emphasize the importance of active management such as subduroperitoneal shunting to drain the cerebrospinal fluid in the Sotos syndrome.
Complete L1-L2 Lateral Dislocation without Fracture and Neurologic Deficit in a Child
Authors: Guzel A. , Belen D. , Tatli M. , Simsek S. , Guzel E.
Published: April 2006

Spinal injuries in the infantile age group are relatively rare, mainly due to anatomical and biomechanical features of the pediatric spine. With its hypermobile character, pediatric spine can withstand trauma without fracture, and the elastic nature of the young spine allows easy slippage between segments, especially under the age of 8. Clinically, a few of the cases present with subluxation only, which seldom involve the lumbar level. We report an extremely rare case of traumatic complete upper lumbar lateral lystesis in a 3-year-old boy. The patient was treated conservatively and followed up for 2 years with some degree of correction.
Effects of Ghrelin upon Gonadotropin-Releasing Hormone and Gonadotropin Secretion in Adult Female Rats: In vivo and in vitro Studies
Authors: Fernández-Fernández Rafael , Tena-Sempere Manuel , Navarro Víctor M. , Barreiro María L. , Castellano Juan M. , Aguilar Enrique , Pinilla Leonor
Published: April 2006

A reproductive facet of ghrelin, a stomach-derived orexigenic peptide involved in energy homeostasis, has been recently suggested, and predominantly inhibitory effects of ghrelin upon luteinizing hormone (LH) secretion have been demonstrated in rat models. Yet, the modulatory actions of ghrelin on the gonadotropic axis remain scarcely evaluated. We report herein a detailed analysis of the effects of ghrelin upon LH and follicle-stimulating hormone (FSH) secretion in the female rat, using a combination of in vivo and in vitro approaches. Intracerebroventricular administration of ghrelin (3 nmol/rat) evoked a significant inhibition of LH secretion in cyclic female rats throughout the estrous cycle (proestrus afternoon, estrus, metestrus), as well as in ovariectomized females. In good agreement, gonadotropin-releasing hormone (GnRH) secretion by hypothalamic fragments from ovariectomized females was significantly inhibited by ghrelin. In contrast, ghrelin dose-dependently stimulated basal LH and FSH secretion by pituitary tissue in vitro; a phenomenon that was proven dependent on the phase of estrous cycle, as it was neither detected at estrus nor observed after ovariectomy. Conversely, GnRH-stimulated LH secretion in vitro was persistently inhibited by ghrelin regardless of the stage of the cycle, whereas stimulated FSH secretion was only inhibited by ghrelin at estrus. In addition, cyclic fluctuations in mRNA levels of growth hormone secretagogue receptor (GHS-R)1a, i.e. the functional ghrelin receptor, were observed in the pituitary, with low values at estrus and metestrus. GHS-R1a mRNA levels, however, remained unchanged after ovariectomy. In summary, our data illustrate a complex mode of action of ghrelin upon the gonadotropic axis, with predominant inhibitory effects at central (hypothalamic) levels and upon GnRH-induced gonadotropin secretion, but direct stimulatory actions on basal LH and FSH secretion. Overall, our results further document the reproductive role of ghrelin, which might be relevant for the integrated control of energy balance and reproduction.
Identifying Inflamed Carotid Plaques Using In Vivo USPIO-Enhanced MR Imaging to Label Plaque Macrophages
Authors: Trivedi Rikin A. , Mallawarachi Chinthake , U-King-Im Jean-Marie , Graves Martin J. , Horsley Jo , Goddard Martin J. , Brown Andrew , Wang Liqun , Kirkpatrick Peter J. , Brown John , Gillard Jonathan H.
Published: April 2006

Background—

Inflammation within atherosclerotic lesions contributes to plaque instability and vulnerability to rupture. We set out to evaluate the use of a macrophage labeling agent to identify carotid plaque inflammation by in vivo magnetic resonance imaging (MRI).

Methods and Results—

Thirty patients with symptomatic severe carotid stenosis scheduled for carotid endarterectomy underwent multi-sequence MRI of the carotid bifurcation before and after injection of ultrasmall superparamagnetic particles of iron oxide (USPIOs). USPIO particles accumulated in macrophages in 24 of 30 plaques (80%). Areas of signal intensity reduction, corresponding to USPIO/macrophage-positive histological sections, were visualized in 24 of 27 (89%) patients, with an average reduction in signal intensity induced by the USPIO particles of 24% (range, 3.1% to 60.8%).

Conclusions—

USPIO-enhanced MRI can identify plaque inflammation in vivo by accumulation of USPIO within macrophages in carotid plaques.
Degenerative Aortic Valve Stenosis, but not Coronary Disease, Is Associated With Shorter Telomere Length in the Elderly
Authors: Kurz David J. , Kloeckener-Gruissem Barbara , Akhmedov Alexander , Eberli Franz R. , Bühler Ines , Berger Wolfgang , Bertel Osmund , Lüscher Thomas F.
Published: April 2006

Objective—

The mechanisms responsible for the age-related increase in the incidence of calcific aortic valve stenosis (CAS) are unclear but may include telomere-driven cellular senescence. Because telomere length varies widely among individuals of the same age, we hypothesized that patients with shorter telomeres would be prone to develop CAS late in life.

Methods and Results—

Mean telomere length was measured in leukocytes from a cohort of 193 patients ≥70 years of age with and without CAS. Pilot experiments performed in 30 patients with CAS and controls pair-matched for age, sex, and presence or absence of coronary disease demonstrated significantly shorter telomeres in the CAS group both by Southern blot hybridization (5.75±0.55 kbp versus 6.27±0.7 kbp,
P
=0.0023) and by a quantitative polymerase chain reaction-based technique (relative telomere length 0.88±0.19 versus 1.0±0.19,
P
=0.01). This finding was then confirmed in the whole cohort (CAS n=64, controls n=129, relative telomere length=0.86±0.16 versus 0.94±0.12,
P
=0.0003). Both groups were comparable for potential confounding characteristics. Subgroup analysis according to the presence or absence of coronary disease demonstrated no association of this disorder with telomere length.

Conclusions—

In the elderly, calcific aortic stenosis, but not coronary disease, is associated with shorter leukocyte telomere length.
Fibrin and Activated Platelets Cooperatively Guide Stem Cells to a Vascular Injury and Promote Differentiation Towards an Endothelial Cell Phenotype
Authors: de Boer H.C. , Verseyden C. , Ulfman L.H. , Zwaginga J.J. , Bot I. , Biessen E.A. , Rabelink T.J. , van Zonneveld A.J.
Published: April 2006

Objective—

Bone marrow-derived progenitor cells play a role in vascular regeneration. However, their homing to areas of vascular injury is poorly understood. One of the earliest responses to an injury is the activation of coagulation and platelets. In this study we assessed the role of hemostatic components in the recruitment of CD34
+
cells to sites of injury.

Methods and Results—

Using an ex vivo injury model, representing endothelial cell (EC) injury or vessel denudation, we studied homing of CD34
+
under flow. Platelet aggregates facilitated initial tethering and rolling of CD34
+
cells through interaction of P-selectin expressed by platelets and P-selectin glycoprotein ligand-1 (PSGL-1), expressed by CD34
+
cells. Ligation of PSGL-1 activated adhesion molecules on CD34
+
cells, ultimately leading to firm adhesion of CD34
+
cells to tissue factor-expressing ECs or to fibrin-containing thrombi formed on subendothelium. We also demonstrate that fibrin-containing thrombi can support migration of CD34
+
cells to the site of injury and subsequent differentiation toward a mature EC phenotype. Additionally, intravenously injected CD34

+

cells homed in vivo to denuded arteries in the presence of endogenous leukocytes.

Conclusions—

We provide evidence that hemostatic factors, associated with vascular injury, provide a regulatory microenvironment for re-endothelialization mediated by circulating progenitor cells.
Estrogen Receptor β Protects the Murine Heart Against Left Ventricular Hypertrophy
Authors: Babiker Fawzi A. , Lips Daniel , Meyer Rainer , Delvaux Els , Zandberg Pieter , Janssen Ben , van Eys Guillaume , Grohé Christian , Doevendans Pieter A.
Published: April 2006

Background—

Left ventricular hypertrophy (LVH) displays significant gender-based differences. 17β-estradiol (E2) plays an important role in this process because it can attenuate pressure overload hypertrophy via 2 distinct estrogen receptors (ERs): ERα and ERβ. However, which ER is critically involved in the modulation of LVH is poorly understood. We therefore used ERα-deficient (ERα
−
/
−
) and ERβ-deficient (ERβ
−
/
−
) mice to analyze the respective ER-mediated effects.

Methods and Results—

Respective ER-deficient female mice were ovariectomized and were given E2 or placebo subcutaneously using 60-day release pellets. After 2 weeks, they underwent transverse aortic constriction (TAC) or sham operation. In ERα
−
/
−
animals, TAC led to a significant increase in ventricular mass compared with sham operation. E2 treatment reduced TAC induced cardiac hypertrophy significantly in wild-type (WT) and ERα
−
/
−
mice but not in ERβ
−/−
mice. Biochemical analysis showed that E2 blocked the increased phosphorylation of p38–mitogen-activated protein kinase observed in TAC-treated ERα
−
/
−
mice. Moreover, E2 led to an increase of ventricular atrial natriuretic factor expression in WT and ERα
−
/
−
mice.

Conclusions—

These findings demonstrate that E2, through ERβ-mediated mechanisms, protects the murine heart against LVH.