bluuebunny/crossref_metadata_2025 huggingface dataset:
Branch-cut singularities in thermodynamics of Fermi liquid systems
Authors: Shekhter Arkady , Finkel'stein Alexander M.
Published: October 2006

The recently measured spin susceptibility of the two-dimensional electron gas exhibits a strong dependence on temperature, which is incompatible with the standard Fermi liquid phenomenology. In this article, we show that the observed temperature behavior is inherent to ballistic two-dimensional electrons. Besides the single-particle and collective excitations, the thermodynamics of Fermi liquid systems includes effects of the branch-cut singularities originating from the edges of the continuum of pairs of quasiparticles. As a result of the rescattering induced by interactions, the branch-cut singularities generate nonanalyticities in the thermodynamic potential that reveal themselves in anomalous temperature dependences. Calculation of the spin susceptibility in such a situation requires a nonperturbative treatment of the interactions. As in high-energy physics, a mixture of the collective excitations and pairs of quasiparticles can effectively be described by a pole in the complex momentum plane. This analysis provides a natural explanation for the observed temperature dependence of the spin susceptibility, both in sign and in magnitude.
Differences in potential for amino acid change after mutation reveals distinct strategies for κ and λ light-chain variation
Authors: Hershberg Uri , Shlomchik Mark J.
Published: October 2006

B cells generate varied yet functional clones under high rates of mutation of their V genes. It has been proposed that as a result of the opposing demands of diversification and preservation of integrity, the V genes of heavy and light chains have evolved to overexpress codons prone to amino acid change in their complementarity determining regions (CDR) compared with the framework (FW) regions. We have analyzed the germ-line V genes of heavy and light chains (both κ and λ), comparing codons of CDR and FW of the germ-line V regions both to each other and to control regions. We found that in both germ-line heavy chains and λ chains, CDR codons are prone to replacement mutations, whereas in the FW, the opposite is true. Furthermore, the difference between CDR and FW in heavy chains and λ chains is based on codons that are prone to nonconservative changes of amino acid. In contrast, in germ-line κ chains, the codons in both CDR and FW are more prone to replacement mutations. We also demonstrated that negative selection during immune responses is more sensitive to nonconservative amino acid substitutions than overall amino acid change, demonstrating the applicability of our analysis to real-time process of selection in the immune system. The differences in germ-line κ and λ light chains' potential reaction to mutation suggests that via these two differently evolved light-chain types, the B cell repertoire encompasses two different strategies to balance diversity and stability in an immune response.
Cell++—simulating biochemical pathways
Authors: Sanford Chris , Yip Matthew L.K. , White Carl , Parkinson John
Published: October 2006

Motivation: With the generation of a wealth of information, detailing cellular components, their functions and interactions, there is a growing need for the development of new computational tools capable of interpreting these data within spatial and dynamic contexts. Here, we introduce Cell++, a novel stochastic simulation environment with the capacity to study a wide variety of biochemical processes within a spatial context.

Results: Focusing on three case studies, we highlight the potential impact of spatial organization in the evolution and engineering of signaling and metabolic pathways. In addition to altering signaling and metabolic efficiency, simulations also demonstrated features consistent with the phenomenon of metabolic channeling.

Availability: Cell++ is licensed under the GNU general public license (GPL) and has been successfully implemented under Linux and IRIX operating systems. Source code together with a simple tutorial is available at .

Contact:  jparkin@sickkids.ca

Supplementary information: Supplementary data for this paper are available at Bioinformatics online.
Supporting the SBML layout extension
Authors: Deckard Anastasia , Bergmann Frank T. , Sauro Herbert M.
Published: October 2006

Motivation: Researchers studying large or complex biochemical networks would benefit from the ability to automatically create lucid visualizations and store them in a portable and widely accepted format.

Summary: Two modules, SBMLSupportLayout and SBWAutoLayout, support reading, creating, manipulating and writing layout information for biochemical models. SBMLSupportLayout can read, update, add and render model layout information. SBWAutoLayout can automatically layout models, graphically manipulate model layout and generate layout information for models without layout information.

Availability: SBMLSupportLayout and SBWAutoLayout are distributed with the Systems Biology Workbench (SBW), which can be downloaded from . Additionally, their visualization and layout capabilities are available online at . Both modules run on Win32, Linux and the Mac OS X version is forthcoming.

Contact:  fbergman@kgi.edu
Parameter estimation using Simulated Annealing for S-system models of biochemical networks
Authors: Gonzalez Orland R. , Küper Christoph , Jung Kirsten , Naval Prospero C. , Mendoza Eduardo
Published: October 2006

Motivation: High-throughput technologies now allow the acquisition of biological data, such as comprehensive biochemical time-courses at unprecedented rates. These temporal profiles carry topological and kinetic information regarding the biochemical network from which they were drawn. Retrieving this information will require systematic application of both experimental and computational methods.

Results: S-systems are non-linear mathematical approximative models based on the power-law formalism. They provide a general framework for the simulation of integrated biological systems exhibiting complex dynamics, such as genetic circuits, signal transduction and metabolic networks. We describe how the heuristic optimization technique simulated annealing (SA) can be effectively used for estimating the parameters of S-systems from time-course biochemical data. We demonstrate our methods using three artificial networks designed to simulate different network topologies and behavior. We then end with an application to a real biochemical network by creating a working model for the cadBA system in Escherichia coli.

Availability: The source code written in C++ is available at . All the necessary programs including the required compiler are described in a document archived with the source code.

Contact:  gonzalez@bio.ifi.lmu.de

Supplementary information: Supplementary material is available at Bioinformatics online.
Contrasting evolution of expression differences in the testis between species and subspecies of the house mouse
Authors: Voolstra Christian , Tautz Diethard , Farbrother Patrick , Eichinger Ludwig , Harr Bettina
Published: October 2006

Regulatory changes in genes involved in reproduction are thought to be prime targets for divergence during speciation, since they are expected to play an important role in sexual selection and sexual conflict. We used microarray analysis of RNA from different wild populations of house mouse subspecies (includingMus m. musculus,Mus m. domesticus, andMus m. castaneus) and from the sister speciesMus spretusto test this assumption. A comparison of expression divergence in brain, liver/kidney, and testis shows a major difference in the evolutionary dynamics of testis-related genes. While the comparison between species confirms an excess in divergence in testis genes, we find that all comparisons between subspecies yield only a very small number of genes with significantly different expression levels in the testis. These results suggest that the early phase of the speciation process may not be driven by regulatory changes in genes that are potential targets of sexual selection, and that the divergence in these genes is only established during a later phase of the speciation process.
Foreign Banks in Transition Countries: To Whom Do They Lend and How Are They Financed?
Authors: De Haas Ralph , Naaborg Ilko
Published: October 2006

We use focused interviews with managers of foreign parent banks and their affiliates in Central Europe and the Baltic States to analyze the small‐business lending and internal capital markets of multinational financial institutions. Our approach allows us to complement the standard empirical literature, which has difficulty in analyzing important issues such as lending technologies and capital allocation. We find that the acquisition of local banks by foreign banks has not led to a persistent bias in these banks' credit supply toward large multinational corporations. Instead, increased competition and the improvement of subsidiaries' lending technologies have led foreign banks to gradually expand into the SME and retail markets. Second, it is demonstrated that local bank affiliates are strongly influenced by the capital allocation and credit steering mechanisms of the parent bank.
PHARMACOGENETICS, RACE AND GLOBAL INJUSTICE1
Authors: HOLM SØREN
Published: October 2006

This paper discusses the link between pharmacogenetics and race, and the global justice issues that the introduction of pharmacogenetics in pharmaceutical research and clinical practice will raise. First, it briefly outlines the likely impact of pharmacogenetics on pharmaceutical research and clinical practice within the next five to ten years and then explores the link between pharmacogenetic traits and ‘race’. It is shown that any link between apparent race and pharmacogenetics is problematic and that race cannot be used as a proxy for pharmacogenetic knowledge. The final section considers the implications of the development of pharmacogenetics for health care systems in low‐ and middle‐income countries.
Right Ventricular Outflow Tract Pacing: Radiographic and Electrocardiographic Correlates of Lead Position
Authors: McGAVIGAN ANDREW D. , ROBERTS‐THOMSON KURT C. , HILLOCK RICHARD J. , STEVENSON IRENE H. , MOND HARRY G.
Published: October 2006

Objective:
To characterize the pacing site in an unselected series of patients undergoing right ventricular outflow tract (RVOT) lead placement and investigate the role of the electrocardiogram (ECG) in predicting implantation.

Background:
Right ventricular apical pacing is associated with long‐term adverse effects on left ventricular function, fuelling interest in alternative pacing sites, especially the RVOT. Previous studies have been conflicting, possibly due to poor definition of pacing site within the RVOT.

Methods:
In 150 patients undergoing pacemaker implantation, implanters were asked to place the lead in the RVOT. Radiographs were performed in the antero‐posterior (AP) and 40° right and left anterior‐oblique projections post procedure. Fifty‐six had left lateral radiographs. Lead position was categorized using AP/RAO (right anterior oblique) to confirm RVOT placement and left anterior oblique to distinguish free wall from septum. A 12‐lead ECG was performed during ventricular pacing.

Results:
Leads were below the RVOT in 18. Of the remaining 132, the majority (94%) were in the inferior/low RVOT. Eighty‐one out of 132 were septal and 51 free wall. Septal sites were associated with shorter QRS duration (134 ms vs 143 ms, P < 0.02). Free wall sites displayed more frequent notching of the inferior leads (P < 0.01). A negative deflection in lead I provided a positive predictive value of 90% for septal sites. In those with lateral radiographs, a posteriorly projected lead was 100% specific for septal placement.

Conclusions:
This study demonstrates the heterogeneity of lead placement within the RVOT. Septal and free wall sites display characteristic ECG patterns which may be used to aid placement. The left lateral radiograph is useful in confirming a true septal location.
Ventricular Repolarization and Heart Rate Responses During Cardiovascular Autonomic Function Testing in LQT1 Subtype of Long QT Syndrome
Authors: HAAPALAHTI PETRI , VIITASALO MATTI , PERHONEN MERJA , MÄKIJÄRVI MARKKU , VÄÄNÄNEN HEIKKI , OIKARINEN LASSE , HEKKALA ANNA‐MARI , SALORINNE YRJÖ , SWAN HEIKKI , TOIVONEN LAURI
Published: October 2006

Background: In the most prevalent LQT1 form of inherited long QT syndrome symptoms often occur during abrupt physical or emotional stress. Sympathetic stimulation aggravates repolarization abnormalities in experimental LQT1 models. We hypothesized that autonomic function tests might reveal the abnormal repolarization in asymptomatic LQT1 patients.

Methods: We measured heart rates (HRs) and QT intervals in nine asymptomatic carriers of a C‐terminal KCNQ1 mutation and 8 unaffected healthy subjects using an approach of global QT values derived from 28 simultaneous electrocardiographic leads on beat‐to‐beat base during Valsalva maneuver, mental stress, sustained handgrip, and light supine exercise.

Results: LQT1 patients exhibited impaired shortening of both QTpeak and QTend intervals during autonomic interventions but exaggerated lengthening of the intervals—a QT overshoot—during the recovery phases. The number of tests with a QT overshoot was 2.4 ± 1.7 in LQT1 patients and 0.8 ± 0.7 in unaffected subjects (P = 0.02). Valsalva strain prolonged T wave peak to T wave end interval (TPE) in LQT1 but not in unaffected patients. LQT1 patients showed diminished HR acceleration in response to adrenergic challenge whereas HR responses to vagal stimuli were similar in both groups.

Conclusions: Standard cardiovascular autonomic provocations induce a QT interval overshoot during recovery in asymptomatic KCNQ1 mutation carriers. Valsalva maneuver causes an exaggerated fluctuation of QT and TPE intervals partly explaining the occurrence of cardiac events during abrupt bursts of autonomic activity in LQT1 patients.
Appropriate Result from an Inappropriate ICD Shock
Authors: DAVIS DARRYL R. , GOLLOB MICHAEL H. , GREEN MARTIN S. , LEMERY ROBERT , TANG ANTHONY S. , BIRNIE DAVID H.
Published: October 2006

A case of inappropriate detection of an ungrounded external AC current by an implantable cardioverter defibrillator (ICD) is reported. The resultant ICD shock dislodged the patient from the electrical source, thus preventing injury or electrocution.
Reasons for choosing dentistry as a career: a study involving male and female first‐year students in Peru
Authors: Bernabé E. , Icaza J. L. , Delgado‐Angulo E. K.
Published: October 2006

Abstract  The aim of this study was to compare the reported reasons to choose dentistry as a career between Peruvian male and female first‐year students. A self‐completion questionnaire was administered to 75 first‐year students registered at the Faculty of Dentistry of the Universidad Peruana Cayetano Heredia, Lima, Peru. The questionnaire comprised 16 items grouped into four categories (economic, professional, vocational and personal background). Students rated the importance of each item for selecting dentistry as a career on a Likert‐type scale of five points. The Mann–Whitney test was used to compare groups and item scores by gender. A male/female proportion of 1/2.1 was found in the pool of participating students. When group and item scores were compared between genders, statistically significant differences were only found for vocational and personal background reasons (P < 0.05); however, the three reasons that obtained higher scores for each gender were found to be different. It is recommended that further studies be conducted to increase the sample, by extending the study and evaluating not only reasons for choosing dentistry, but also other factors that may influence the decision.
Sickle cell disease due to compound heterozygosity for Hb S and a novel 7.7‐kb β‐globin gene deletion
Authors: Andersson B. Anders R. , Wering Mikaela E. L. , Luo Hong‐Yuan , Basran Raveen K. , Steinberg Martin H. , Smith Hedy P. , Chui David H. K.
Published: October 2006

A young woman originally from Cape Verde islands presented with mild sickle cell disease. Her blood counts and hemoglobin analysis results initially suggested that she might be either homozygous for the sickle cell hemoglobin (Hb S) with concomitant α‐thalassemia, or compound heterozygous for Hb S and β0‐thalassemia, deletional δβ‐thalassemia or hereditary persistence of fetal hemoglobin (HPFH). We utilized a novel polymerase chain reaction (PCR)‐based screening technique and found a hitherto unrecognized 7.7‐kb deletion, starting from the HBB IVSII to 3′ downstream of the β‐globin gene. This diagnostic approach can be applied to decipher other similar deletional mutations. This is the second known deletion that removes the 3′‐end but preserves the integrity of the 5′‐end of the β‐globin gene. Furthermore, the identification of the deletion allows proper genetic counseling for affected families.
Purinergic 2 receptor blockade prevents the responses of group IV afferents to post‐contraction circulatory occlusion
Authors: Kindig Angela E. , Hayes Shawn G. , Kaufman Marc P.
Published: October 2006

ATP, by activating purinergic 2 (P2) receptors on group III and IV afferents, is thought to evoke the metabolic component of the exercise pressor reflex. Previously we have shown that injection of PPADS, a P2 receptor antagonist, into the arterial supply of skeletal muscle of decerebrated cats attenuated the responses of group III and IV afferents to static contraction while the muscles were freely perfused. We have now tested the hypothesis that injection of PPADS (10 mg kg−1) attenuated the responses of group III (n= 13) and group IV afferents (n= 9) to post‐contraction circulatory occlusion. In the present study, we found that PPADS attenuated the group III afferent responses to static contraction during circulatory occlusion (P < 0.05). Likewise, PPADS abolished the group IV afferent responses to static contraction during occlusion (P= 0.001). During a 1 minute period of post‐contraction circulatory occlusion, four of the 13 group III afferents and eight of the nine group IV afferents maintained their increased discharge. A Fischer's exact probability test revealed that more group IV afferents than group III afferents were stimulated by post‐contraction circulatory occlusion (P < 0.02). In addition, the nine group IV afferents increased their mean discharge rate over baseline levels during the post‐contraction circulatory occlusion period, whereas the 13 group III afferents did not (P < 0.05). PPADS abolished this post‐contraction increase in discharge by the group IV afferents (P < 0.05). Our findings suggest that P2 receptors on group IV afferents play a role in evoking the metabolic component of the exercise pressor reflex.
Histaminergic and glycinergic modulation of GABA release in the vestibular nuclei of normal and labyrinthectomised rats
Authors: Bergquist Filip , Ruthven Alasdair , Ludwig Mike , Dutia Mayank B.
Published: October 2006

Vestibular compensation (the behavioural recovery that follows unilateral vestibular de‐afferentation), is facilitated by histamine, and is associated with increased central histamine release and alterations in histamine H3 receptor expression in the vestibular nuclei. However, little is known of the effects of histamine on neurotransmission in the vestibular nuclei, and the mechanisms by which histamine may influence compensation are unclear. Here we examined the modulatory effects of histaminergic agents on the release of amino acid neurotransmitters in slices of the medial vestibular nucleus (MVN) prepared from normal and labyrinthectomised rats. The release of GABA, but not glutamate, glycine or aspartate, was robustly and reproducibly evoked by a high‐K+ stimulus applied to normal MVN slices. Histamine inhibited the evoked release of GABA, both through a direct action on presynaptic H3 receptors (presumably located on GABAergic terminals), and through a novel, indirect pathway that involved the increased release of glycine by activation of postsynaptic H1/H2 receptors (presumably on glycinergic neurons). After unilateral labyrinthectomy (UL), the direct H3 receptor‐mediated inhibition of GABA release was profoundly downregulated in both ipsi‐lesional and contra‐lesional MVNs. This effect appeared within 25 h post‐UL and persisted for at least 3 weeks post‐UL. In addition, at 25 h post‐UL the indirect glycinergic pathway caused a marked suppression of GABA release in the contra‐lesional but not ipsi‐lesional MVN, which was overcome by strychnine. Stimulation of histamine H3 receptors at 25 h post‐UL restored contra‐lesional GABA release to normal, suggesting that acutely after UL H3 receptors may strongly modulate glycinergic and GABAergic neurotransmission in the MVN. These findings are the first to demonstrate the modulatory actions of the histaminergic system on neurotransmission in the vestibular nuclei, and the changes that occur during vestibular system plasticity. During vestibular compensation, histaminergic modulation of glycine and GABA release may contribute to the rebalancing of neural activity in the vestibular nuclei of the lesioned and intact sides.
STATIC QUARK POTENTIAL AND THE RENORMALIZED ANISOTROPY ON TADPOLE IMPROVED ANISOTROPIC LATTICES
Authors: LIU WEI , CHEN YING , GONG MING , LI XIN , LIU CHUAN , MENG GUOZHAN
Published: October 2006

Static quark potential is studied using a tadpole improved gauge lattice action. The scale is set using the potential for a wide range of bare parameters. The renormalized anisotropy of the lattice is also measured.
BEYOND UNITARY PARASUPERSYMMETRY FROM THE VIEWPOINT OF h3 AND h4 HEISENBERG ALGEBRAS
Authors: CHENAGHLOU A. , FAKHRI H.
Published: October 2006

Using the partition of the number p-1 into p-1 real parts which are not equal with each other necessarily, we develop the unitary parasupersymmetry algebra of arbitrary order p so that the well-known Rubakov–Spiridonov–Khare parasupersymmetry becomes a special case of the developed one. It is shown that the developed algebra is realized by simple harmonic oscillator and Landau problem on a flat surface with the symmetries of h3 and h4 Heisenberg–Lie algebras. For this new parasupersymmetry, the well-known unitary condition is violated, however, unitarity of the corresponding algebra is structurally conserved. Moreover, the components of the bosonic Hamiltonian operator are derived as functions from the mean value of the partition numbers with their label weight function.
RICCI FLOWS AND SOLITONIC pp-WAVES
Authors: VACARU SERGIU I.
Published: October 2006

We find exact solutions describing Ricci flows of four-dimensional pp-waves nonlinearly deformed by two-/three-dimensional solitons. Such solutions are parametrized by five-dimensional metrics with generic off-diagonal terms and connections with nontrivial torsion which can be related, for instance, to antisymmetric tensor sources in string gravity. There are defined nontrivial limits to four-dimensional configurations and the Einstein gravity.
Effect of long-term muscle paralysis on human single fiber mechanics
Authors: Malisoux Laurent , Jamart Cécile , Delplace Krystel , Nielens Henri , Francaux Marc , Theisen Daniel
Published: October 2006

This study compared human muscles following long-term reduced neuromuscular activity to those with normal functioning regarding single fiber properties. Biopsies were obtained from the vastus lateralis of 5 individuals with chronic (>3 yr) spinal cord injury (SCI) and 10 able-bodied controls (CTRL). Chemically skinned fibers were tested for active and passive mechanical characteristics and subsequently classified according to myosin heavy chain (MHC) content. SCI individuals had smaller proportions of type I (11 ± 7 vs. 34 ± 5%) and IIa fibers (11 ± 6 vs. 31 ± 5%), whereas type IIx fibers were more frequent (40 ± 13 vs. 7 ± 3%) compared with CTRL subjects ( P < 0.05). Cross-sectional area and peak force were similar in both groups for all fiber types. Unloaded shortening velocity of fibers from paralyzed muscles was higher in type IIa, IIa/IIx, and IIx fibers (26, 65, and 47%, respectively; P < 0.01). Consequently, absolute peak power was greater in type IIa (46%; P < 0.05) and IIa/IIx fibers (118%; P < 0.01) of the SCI group, whereas normalized peak power was higher in type IIa/IIx fibers (71%; P < 0.001). Ca2+ sensitivity and passive fiber characteristics were not different between the two groups in any fiber type. Composite values (average value across all fibers analyzed within each study participant) showed similar results for cross-sectional area and peak force, whereas maximal contraction velocity and fiber power were more than 100% greater in SCI individuals. These data illustrate that contractile performance is preserved or even higher in the remaining fibers of human muscles following reduced neuromuscular activity.
The effect of running, strength, and vibration strength training on the mechanical, morphological, and biochemical properties of the Achilles tendon in rats
Authors: Legerlotz Kirsten , Schjerling Peter , Langberg Henning , Brüggemann Gert-Peter , Niehoff Anja
Published: October 2006

Compared with muscle or bone, there is a lack of information about the relationship between tendon adaptation and the applied loading characteristic. The purpose of the present study was to analyze the effect of different exercise modes characterized by very distinct loading patterns on the mechanical, morphological, and biochemical properties of the Achilles tendon. Sixty-four female Sprague-Dawley rats were divided into five groups: nonactive age-matched control (AMC; n = 20), voluntary wheel running (RT; n = 20), vibration strength-trained (LVST; n = 12), high-vibration strength-trained (HVST; n = 6), and high strength-trained (HST; n = 6) group. After a 12-wk-long experimental period, the Achilles tendon was tested mechanically and the cross-sectional area, the soleus and gastrocnemius muscle mass, and mRNA concentration of collagen I, collagen III, tissue inhibitor of metalloproteinase-1 (TIMP-1), transforming growth factor-β, connective tissue growth factor, and matrix metalloproteinase-2 was determined. Neither in the LVST nor in the HVST group could any adaptation of the Achilles tendon be detected, although the training had an effect on the gastrocnemius muscle mass in the LVST group ( P < 0.05). In the HST group, the highest creep was found, but the effect was more pronounced compared with the LVST group ( P < 0.05) than with the AMC group. That indicates that this was rather induced by the low muscle mass rather than by training. However, the RT group had a higher TIMP-1 mRNA concentration in the Achilles tendon in contrast to AMC group ( P < 0.05), which suggests that this exercise mode may have an influence on tendon adaptation.
Short-term strength training and the expression of myostatin and IGF-I isoforms in rat muscle and tendon: differential effects of specific contraction types
Authors: Heinemeier K. M. , Olesen J. L. , Schjerling P. , Haddad F. , Langberg H. , Baldwin K. M. , Kjaer M.
Published: October 2006

In skeletal muscle, an increased expression of insulin like growth factor-I isoforms IGF-IEa and mechano-growth factor (MGF) combined with downregulation of myostatin is thought to be essential for training-induced hypertrophy. However, the specific effects of different contraction types on regulation of these factors in muscle are still unclear, and in tendon the functions of myostatin, IGF-IEa, and MGF in relation to training are unknown. Female Sprague-Dawley rats were subjected to 4 days of concentric, eccentric, or isometric training ( n = 7–9 per group) of the medial gastrocnemius, by stimulation of the sciatic nerve during general anesthesia. mRNA levels for myostatin, IGF-IEa, and MGF in muscle and Achilles' tendon were measured by real-time RT-PCR. Muscle myostatin mRNA decreased in response to all types of training (2- to 8-fold) ( P < 0.05), but the effect of eccentric training was greater than concentric and isometric training ( P < 0.05). In tendon, myostatin mRNA was detected, but no changes were seen after exercise. IGF-IEa and MGF increased in muscle (up to 15-fold) and tendon (up to 4-fold) in response to training ( P < 0.01). In tendon no difference was seen between training types, but in muscle the effect of eccentric training was greater than concentric training for both IGF-IEa and MGF ( P < 0.05), and for IGF-IEa isometric training had greater effect than concentric ( P < 0.05). The results indicate a possible role for IGF-IEa and MGF in adaptation of tendon to training, and the combined changes in myostatin and IGF-IEa/MGF expression could explain the important effect of eccentric actions for muscle hypertrophy.
ATP Release From Activated Neutrophils Occurs via Connexin 43 and Modulates Adenosine-Dependent Endothelial Cell Function
Authors: Eltzschig Holger K. , Eckle Tobias , Mager Alice , Küper Natalie , Karcher Christian , Weissmüller Thomas , Boengler Kerstin , Schulz Rainer , Robson Simon C. , Colgan Sean P.
Published: October 2006

Extracellular ATP liberated during hypoxia and inflammation can either signal directly on purinergic receptors or can activate adenosine receptors following phosphohydrolysis to adenosine. Given the association of polymorphonuclear leukocytes (PMNs) with adenine-nucleotide/nucleoside signaling in the inflammatory milieu, we hypothesized that PMNs are a source of extracellular ATP. Initial studies using high-performance liquid chromatography and luminometric ATP detection assays revealed that PMNs release ATP through activation-dependent pathways. In vitro models of endothelial barrier function and neutrophil/endothelial adhesion indicated that PMN-derived ATP signals through endothelial adenosine receptors, thereby promoting endothelial barrier function and attenuating PMN/endothelial adhesion. Metabolism of extracellular ATP to adenosine required PMNs, and studies addressing these metabolic steps revealed that PMN express surface ecto-apyrase (CD39). In fact, studies with PMNs derived from cd39
−/−
mice showed significantly increased levels of extracellular ATP and lack of ATP dissipation from their supernatants. After excluding lytic ATP release, we used pharmacological strategies to reveal a potential mechanism involved in PMN-dependent ATP release (eg, verapamil, dipyridamole, brefeldin A, 18-α-glycyrrhetinic acid, connexin-mimetic peptides). These studies showed that PMN ATP release occurs through connexin 43 (Cx43) hemichannels in a protein/phosphatase-A–dependent manner. Findings in human PMNs were confirmed in PMNs derived from induced Cx43
−/−
mice, whereby activated PMNs release less than 15% of ATP relative to littermate controls, whereas Cx43 heterozygote PMNs were intermediate in their capacity for ATP release (
P
<0.01). Taken together, our results identify a previously unappreciated role for Cx43 in activated PMN ATP release, therein contributing to the innate metabolic control of the inflammatory milieu.
Physical Activity Improves Long-Term Stroke Outcome via Endothelial Nitric Oxide Synthase–Dependent Augmentation of Neovascularization and Cerebral Blood Flow
Authors: Gertz Karen , Priller Josef , Kronenberg Golo , Fink Klaus B. , Winter Benjamin , Schröck Helmut , Ji Shengbo , Milosevic Milan , Harms Christoph , Böhm Michael , Dirnagl Ulrich , Laufs Ulrich , Endres Matthias
Published: October 2006

Physical activity upregulates endothelial nitric oxide synthase (eNOS), improves endothelium function, and protects from vascular disease. Here, we tested whether voluntary running would enhance neovascularization and long-term recovery following mild brain ischemia. Wild-type mice were exposed to 30 minutes of middle-cerebral artery occlusion (MCAo) and reperfusion. Continuous voluntary running on wheels conferred long-term upregulation of eNOS in the vasculature and of endothelial progenitor cells (EPCs) in the spleen and bone marrow (BM). This was associated with higher numbers of circulating EPCs in the blood and enhanced neovascularization. Moreover, engraftment of TIE2/LacZ-positive BM-derived cells was increased in the ischemic brain. Four weeks after the insult, trained animals showed higher numbers of newly generated cells in vascular sites, increased density of perfused microvessels and sustained augmentation of cerebral blood flow within the ischemic striatum. Moreover, running conferred tissue sparing and improved functional outcome at 4 weeks. The protective effects of running on angiogenesis and outcome were completely abolished when animals were treated with a NOS inhibitor or the antiangiogenic compound endostatin after brain ischemia, and in animals lacking eNOS expression. Voluntary physical activity improves long-term stroke outcome by eNOS-dependent mechanisms related to improved angiogenesis and cerebral blood flow.
A Mesoscale Data Analysis and Downscaling Method over Complex Terrain
Authors: Steinacker Reinhold , Ratheiser Matthias , Bica Benedikt , Chimani Barbara , Dorninger Manfred , Gepp Wolfgang , Lotteraner Christoph , Schneider Stefan , Tschannett Simon
Published: October 2006

A mesoscale data analysis method for meteorological station reports is presented. Irregularly distributed measured values are combined with measurement-independent a priori information about the modification of analysis fields due to topographic forcing. As a physical constraint to a thin-plate spline interpolation, the so-called “fingerprint method” recognizes patterns of topographic impact in the data and allows for the transfer of information to data-sparse areas. The results of the method are small-scale interpolation fields on a regular grid including topographically induced patterns that are not resolved by the station network. Presently, the fingerprint method is designed for the analysis of scalar meteorological variables like reduced pressure or air temperature. The principles for the fingerprint technique are based on idealized influence fields. They are calculated for thermal and dynamic surface forcing. For the former, the effects of reduced air volumes in valleys, the elevated heat sources, and the stability of the valley atmosphere are taken into account. The increase of temperature under ideal conditions in comparison to flat terrain is determined on a 1-km grid using height and surface geometry information. For the latter, a perturbation of an originally constant cross-Alpine temperature gradient is calculated by a topographical weighting. As a result, the gradient is steep where the mountain range is high and steep. If, during the interpolation process, some signal of the idealized patterns is found in the station data, it is used to downscale the analysis. It is shown by a cross validation of a case study that the interpolation of a mean sea level pressure field over the Alpine region is improved objectively by the method. Thermally induced mesoscale patterns are visible in the interpolated pressure field.
Evaluation of the Soil Model of the Hydro–Thermodynamic Soil–Vegetation Scheme by Observations and a Theoretically Advanced Numerical Scheme
Authors: Narapusetty Balachandrudu , Mölders Nicole
Published: October 2006

The soil module of the Hydro–Thermodynamic Soil–Vegetation Scheme is evaluated by soil temperature observations and independent theoretical numerical results. To gain the latter, a Galerkin weak finite-element (GWFE) scheme is implemented for solving the heat and water balance equations that are originally solved by a Crank–Nicholson finite-difference (CNFD) scheme. The GWFE scheme captures discontinuities well and has a high phase fidelity. When/where frozen ground thaws and under moderate advection-dominated regimes, peak temperatures simulated with the CNFD scheme are up to seven days off compared with observations and the results of the GWFE scheme. If freeze–thaw cycles repeat for more than a month, CNFD predictions will oscillate ±1 K around the observations but will converge to the observations and results of the GWFE scheme afterward. Under diffusion-dominated regimes, CNFD runs perform well with similar quality to the GWFE predictions. Comparisons of the results of both numerical schemes substantiate that the long spinup time of CNFD simulations results from the numerical scheme and not from the initialization procedure and that the diffusive nature of the CNFD scheme and not parameterized physical processes causes phase shifts. GWFE requires 1.6–2.8 more CPU time than CNFD in this study. Unless CPU time is an issue, the GWFE scheme is recommended because of its high phase fidelity and short spinup.
Mechanisms for the Generation of Mesoscale Vorticity Features in Tropical Cyclone Rainbands
Authors: Franklin Charmaine N. , Holland Greg J. , May Peter T.
Published: October 2006

A high-resolution tropical cyclone model with explicit cloud microphysics has been used to investigate the dynamics and energetics of tropical cyclone rainbands. Analysis of the vorticity interactions that occur within the simulated rainbands demonstrates that couplets of cyclonic–anticyclonic mesovortices can be produced in outer bands. The primary source of this vorticity is the upward tilting of system-generated horizontal vorticity by diabatic heating gradients. The vertical heating gradient in the stratiform cloud also creates a potential vorticity (PV) dipole that accelerates the tangential flow and develops a midlevel jet. The strength of the jet is enhanced by the vortex pair that is oriented radially across the rainband. The Fourier decomposition of the absolute vorticity field shows two counterpropagating vortex Rossby waves associated with the rainband. The wave located on the inner side of the band transports energy toward the vortex center. The outer wave is made up of high wavenumbers and uses the vorticity gradients generated by the rainband. The results support the hypothesis that the heating profile in the stratiform regions of rainbands generates cyclonic PV across the freezing level, which develops a midlevel jet. This mechanism creates a vorticity gradient that enables the propagation of vortex Rossby waves that could allow the rainbands to interact with the mean flow and potentially influence the evolution of the storm by contributing to the symmetric component of vorticity and the development of secondary eyewalls.
Fourier-Ray Modeling of Transient Trapped Lee Waves
Authors: Broutman Dave , Ma Jun , Eckermann Stephen D. , Lindeman John
Published: October 2006

The Fourier-ray method involves ray tracing in a Fourier-transform domain. The ray solutions are then Fourier synthesized to produce a spatial solution. Here previous steady-state developments of the Fourier-ray method are extended to include a transient source of mountain waves. The method is illustrated with an initial value problem in which the background flow is started abruptly from rest and then maintained at steady velocity. The resulting wave transience is modeled in a simple way. All rays that radiate from the mountain, including the initial rays, are assigned the full amplitude of the longtime steady-state solution. Time dependence comes in through the changing position of the initial rays. This is sufficient to account for wave transience in a test case, as demonstrated by comparison with simulations from a mesoscale numerical model.
Precursors to Convection over Peninsular India during March–May in AMSU-B Data
Authors: Puranik Dileep M. , Karekar R. N.
Published: October 2006

In the present work the locations of precursors to summer thunderstorms over peninsular India are sought in images from the Advanced Microwave Sounding Unit-B (AMSU-B). At these locations, moisture maxima and brightness temperature (BT) minima may be expected. Prior literature suggests that the 150-GHz channel is useful in detecting the BT minima due to moisture in the lowest 1 km, the 183.3 ± 7- GHz channel is useful for detecting middle-level moist layers and clouds, and the other 183.3-GHz channels are useful for upper-air features such as high-level dry air incursion or upper-air troughs. Cloudy or moist pixels and low-emissivity ground pixels have similar BTs. The extraction of the locations of BT minima is therefore difficult. The scale 1 or 2 à trous wavelet transform (WT) allows unambiguous location of the BT minima due to clouds or moist regions from AMSU-B images.

On 3–4 April 2001 there was a middle-level moisture incursion over the peninsula and on 17–18 April 2001 there was an upper-level dry air incursion. The wavelet components of AMSU-B data were extracted during these two events. From the Meteosat-5 infrared images it was verified that convection occurred within 2 h of the AMSU-B pass in the low-BT regions separated by the à trous WT. On the other hand, peninsular discontinuities on 3–4 April 2001 and 7 April 2002 and other days in 2002 showed that useful precursors could not be extracted from the 150-GHz signal. The BTs for the 150-GHz channel in dry air are affected significantly by ground altitude and by changes in surface emissivity. Failure and success in precursor detection are both attributed to the variability in the BTs.
Synoptic and Mesoscale Analysis of a High-Latitude Derecho–Severe Thunderstorm Outbreak in Finland on 5 July 2002
Authors: Punkka Ari-Juhani , Teittinen Jenni , Johns Robert H.
Published: October 2006

On 5 July 2002, a rapidly propagating bow echo formed over eastern Finland causing severe wind damage in an exceptionally large area. The Ministry of the Interior’s Emergency Response Centers received nearly 400 thunderstorm-related wind damage reports. The 5 July 2002 case is the highest-latitude derecho that has ever been documented. The bow echo developed ahead of a northeastward-moving 500-hPa trough inside of the warm sector of a secondary low and moved north-northwestward on the eastern (warm) side of the quasi-stationary front. The leading edge of the bow echo was oriented perpendicular to the low-level southerly wind shear and the convective system propagated along the 850-hPa equivalent potential temperature ridge with a speed that was close to the maximum wind throughout the troposphere. It is particularly noteworthy that the synoptic pattern was oriented about 90° counterclockwise when compared with the typical synoptic pattern associated with warm season derechos in the United States. This kind of synoptic situation associated along with the derecho mesoscale convective system’s (MCS’s) motion toward the north-northwest has not been mentioned in literature before. The MCS started as a cluster of thunderstorms and became a bow echo a few hours later. The leading edge of the bow echo had a strong reflectivity gradient and the region of stratiform precipitation was behind the strongest echoes. At the most intense stage, a rear-inflow notch was visible both in radar and satellite pictures. It was in good accordance with the location of an area of the most severe damage. Moreover, the storm-relative winds derived from the proximity sounding in the wake of the system showed the existence of rear-to-front flow above 850 hPa. The downdraft air appeared to originate from 4 km ASL, where the relative humidity was less than 50%. This probably led to enhanced evaporative cooling and the intense cold pool, which propagated faster than the mean wind. In the mesoscale, the 5 July 2002 derecho had many similarities to other derecho MCSs that have been described in the literature.
Orienting Multiple Interviewers: The Use of an Interview Orientation and Standardized Interview
Authors: Boutain Doris M. , Hitti Jane
Published: October 2006

An interviewer orientation protocol and standardized interview can be an effective way of orienting multiple interviews to qualitative research. A standardized interview involves an actor taught to portray a research participant consistently in several interview encounters. In this article, the authors describe the interview protocol, and the development and application of a standardized interview. The benefits of using a standardized interview as a formative method to orient multiple interviewers include assessing the interviewers’ integration of the interview protocol, the nonverbal and verbal presentation of the interview process between interviewers, and the general flow of the interview from interviewer to interviewer. As more qualitative research is conducted using multiple interviewers, the method of an interview protocol and subsequent standardized interview might be helpful when orienting interviewers to the challenges and promises of conducting research using a critical framework.
“Pull Yourself Up by Your Bootstraps”: A Response to Depression in Older Adults
Authors: Switzer Julia F. , Wittink Marsha N. , Karsch Brearley B. , Barg Frances K.
Published: October 2006

Although depression is one of the most common problems among adults in primary care settings, many do not seek or adhere to the treatment regimens suggested by their providers. Understanding the cultural model surrounding depression and its treatment in older adults might provide insight into the development of more effective strategies for addressing the problem in the clinical setting. In this study, the authors conducted semi-structured interviews with adults over age 65. Personal responsibility for the management of depression emerged as a pervasive approach to dealing with depression. Older adults used orientational and movement metaphors to describe the process of moving out of depression. They viewed initiation and follow-through of this process as the sole responsibility of the depressed individual. This attitude might be rooted in the cultural experiences of this particular cohort of older adults and has implications for their use of physical and mental health services for depression.
A Contextual Study of Daily Living Strategies in Neurocognitively Impaired Adults With Schizophrenia
Authors: Gioia Deborah
Published: October 2006

Schizophrenia is a severe mental illness often recognized as a degenerative neurocognitive condition. For some with the disorder, the impairment is fairly mild, but for others, neurocognitive abilities can be severely compromised. In this study, 5 individuals with schizophrenia had been assessed through a laboratory-based neurocognitive battery as having severe impairment. Their neurocognitive status was unknown to the author, and she was able to observe daily tasks and ask questions about strategies they employed while completing tasks, and analyze the data without preconceptions about their status. This study was guided by notions of ecological validity, which is the comparison between lab tests and real-world functioning. Despite their cognitive deficits, these individuals had remarkable strengths, which included drawing supportive people into their worlds to fulfill their daily tasks. These data contribute to the rehabilitation literature and propose remedies for struggles of daily living when one has schizophrenia.