bluuebunny/crossref_metadata_2025 huggingface dataset:
Biosynthesis and Functions of Mycothiol, the Unique Protective Thiol of
Actinobacteria
Authors: Newton Gerald L. , Buchmeier Nancy , Fahey Robert C.
Published: September 2008

Mycothiol (MSH; AcCys-GlcN-Ins) is the major thiol found in
Actinobacteria
and has many of the functions of glutathione, which is the dominant thiol in other bacteria and eukaryotes but is absent in
Actinobacteria
. MSH functions as a protected reserve of cysteine and in the detoxification of alkylating agents, reactive oxygen and nitrogen species, and antibiotics. MSH also acts as a thiol buffer which is important in maintaining the highly reducing environment within the cell and protecting against disulfide stress. The pathway of MSH biosynthesis involves production of GlcNAc-Ins-P by MSH glycosyltransferase (MshA), dephosphorylation by the MSH phosphatase MshA2 (not yet identified), deacetylation by MshB to produce GlcN-Ins, linkage to Cys by the MSH ligase MshC, and acetylation by MSH synthase (MshD), yielding MSH. Studies of MSH mutants have shown that the MSH glycosyltransferase MshA and the MSH ligase MshC are required for MSH production, whereas mutants in the MSH deacetylase MshB and the acetyltransferase (MSH synthase) MshD produce some MSH and/or a closely related thiol. Current evidence indicates that MSH biosynthesis is controlled by transcriptional regulation mediated by σ
B
and σ
R
in
Streptomyces coelicolor
. Identified enzymes of MSH metabolism include mycothione reductase (disulfide reductase; Mtr), the
S
-nitrosomycothiol reductase MscR, the MSH
S
-conjugate amidase Mca, and an MSH-dependent maleylpyruvate isomerase. Mca cleaves MSH
S
-conjugates to generate mercapturic acids (AcCySR), excreted from the cell, and GlcN-Ins, used for resynthesis of MSH. The phenotypes of MSH-deficient mutants indicate the occurrence of one or more MSH-dependent
S
-transferases, peroxidases, and mycoredoxins, which are important targets for future studies. Current evidence suggests that several MSH biosynthetic and metabolic enzymes are potential targets for drugs against tuberculosis. The functions of MSH in antibiotic-producing streptomycetes and in bioremediation are areas for future study.
The Effect of pH on Methyl Mercury Production and Decomposition in Lake Sediments
Authors: Ramial P. S. , Rudd John W. M , Furutam Akira , Xun Luying
Published: September 2008

Mercury methylation was measured in surficial sediments taken from unacidified and experimentally acidified lakes in the Experimental Lakes Area, northwestern Ontario. A reduction in the pH of sediments lowered the rate of 203Hg methylation. Methylation was undetectable at pH <5.0. This decrease in mercury methylation was probably related to a shortage of available inorganic mercury when the pH of the sediment porewater was reduced. Below pH 6.0, inorganic mercury concentrations in porewater, measured with 203Hg, were reduced to less than 20% of that found at unaltered pH. A comparison of methylation and demethylation rates was made at various pH's. The rate of demethylation decreased to a lesser extent than methylation as the pH was lowered. This research indicates that enhanced mercury methylation in the sediment is not responsible for the observed increase in mercury levels in fish from acidified lakes.
Comparative Learning Ability of Selected Fishes
Authors: Coble Daniel W. , Farabee Gordon B. , Anderson Richard O.
Published: September 2008

Fourteen species of freshwater fish were trained to execute a simple conditioned response in a shuttle box – to move in response to light to avoid an electrical shock. There was no relation between learning ability and phylogenetic position. Better learners included striped bass (Morone saxatilis), bigmouth buffalo (Ictiohus cyprinellus), common carp (Cyprinus carpio), and channel catfish (Ictalurus punctatus). Bluegill (Lepomis macrochirus) and northern pike (Esoxlucius) were poor learners. Yellow perch (Perca flavescens) and redbelly tilapia (Tilapia zilli) could not be trained. Some fish retained their learned behavior for months, although performance deteriorated with time. Older channel catfish learned better than juveniles, but there was no difference between juvenile and older largemouth bass (Micropterus salmoides). Temperature (18–28 °C) and feeding level (ranging from starvation for 25 d to ad libitum) did not affect learning of channel catfish, but the protozoan disease, ichthyophthiriasis, and perhaps our treatment of fish for the disease retarded it.
Structural behaviour and design criteria of under-deck cable-stayed bridges and combined cable-stayed bridges. Part 1: Single-span bridges
Authors: Ruiz-Teran A. M. , Aparicio A. C.
Published: September 2008

This paper examines two new types of bridges, namely under-deck cable-stayed bridges and combined cable-stayed bridges, for prestressed concrete road bridges with single-spans of medium length. Both bridge types offer many advantages over conventional schemes in several aspects, such as structural efficiency, enhanced construction possibilities, and both economic and aesthetical considerations. They are very slender structural types with a very high structural efficiency, for which the materials used in the deck are reduced to one third of that in conventional bridges without stay cables. In this paper, the most important aspects of the structural behaviour of these bridge types are set out through the description of a careful selection from an extensive collection of bridges designed and analysed by the authors in a previous research project. In addition, a detailed set of design criteria for these bridge types is presented, based on the results of the extensive parametric study undertaken in the aforementioned research project.
Experimental and theoretical analyses of two-dimensional flows upstream of broad-crested weirs
Authors: Kirkgoz M. Salih , Akoz M. Sami , Oner A. Alper
Published: September 2008

Using the particle image velocimetry (PIV) technique, the laboratory experiments are conducted to measure the velocity fields of two-dimensional turbulent free surface flows upstream of rectangular and triangular broad-crested weirs. The experimental flow cases are analyzed theoretically by a computational fluid dynamics (CFD) modeling in which the finite element method is used to solve the governing equations. In the CFD simulation, the volume of fluid (VOF) method is used to compute the free surfaces of the flows. Using the standard k–ε and standard k–ω turbulence models, the numerical results for the velocity fields and flow profiles are compared with the experimental results for validation purposes. The computed results using k–ω turbulence model on compressed mesh systems are found in good agreement with measured data. The flow cases are also analyzed theoretically using the potential flow (PF) approach, and the numerical results for the velocity fields are compared with measurements.
Influence of compaction temperature on rubberized asphalt mixes and binders
Authors: Lee Soon-Jae , Amirkhanian Serji N. , Shatanawi Khaldoun , Thodesen Carl
Published: September 2008

This research investigates the influence of compaction temperature on rubberized asphalt mixes and binders. For this, four Superpave mix designs for four asphalt binders (control, 3% styrene–butadiene–styrene (SBS)-modified, 10% rubber-modified, and 15% rubber-modified) were carried out. A total of 160 specimens were manufactured at four compaction temperatures of 116, 135, 154, and 173 °C. The binders were artificially short-term aged for 2 h at the mixture compaction temperatures prior to the binder tests. The results from this study showed that: (i) the control and SBS-modified mixtures could have almost the same air–void contents at a wide range of compaction temperatures; (ii) the compaction temperatures significantly affected the volumetric properties of the rubberized mixes; (iii) the aging difference of asphalt binder in the mixture depending on the compaction temperature is not considered to be a main factor affecting the volumetric properties of the mixtures.
Patterns in strategic joint ventures of selected prominent cross-border contractors for 1999–2003
Authors: Abdul-Aziz A.-R. , Cha S.-Y.
Published: September 2008

Scholars have noted that cross-border businesses have been increasingly using alternative forms of overseas involvement instead of going-it-alone. A study was conducted to document and subsequently identify possible patterns from the strategic joint ventures adopted by selected contractors that appeared in the Engineering News Record’s annual top 225 international contractors survey from 1999–2003 inclusively, which was also the framed study period. The modes of strategic joint ventures that became the focus of the study were equity joint venture companies, serial joint ventures, and long-term joint venture contracts. Data was collected entirely from secondary sources, which were triangulated to remove possible biases. The study found patterns in terms of frequency of the various modes, nationality of partners, markets the joint ventures served, and industries the partners belonged to. The findings add to our knowledge on the behaviour of cross-border contractors.
Transférabilité d’un modèle pluie–débit pour la simulation de courbes de débits classés sur des petits bassins non jaugés de l’Amazonie
Authors: Blanco Claudio J.C. , Secretan Yves , Favre Anne-Catherine
Published: September 2008

In Amazonia, because the small catchments are ungauged, it is not possible to analyse them, for example, for hydroelectric power production. Thus, the objective of this paper is to study the transferability of a rainfall–runoff model to simulate flow duration curves for the production of hydroelectric power. The approach is based on the transfer of the impulse response of a model calibrated on two gauged catchments, allowing the evaluation approach permutation between these two catchments. We have, respectively, 7 years and 2 years and 2 months of rainfall and runoff data for these catchments. A sensitivity analysis of the transferability calibration to the sample size is carried out to determine the shortest flow period gauged on the receptor catchment, which produces results comparable to those calibrated with the maximum samples size. This analysis evaluates fieldwork on the ungauged sites of the region.
Fertilization in the white chiton, Stenosemus albus, with implications for its phylogenetic position
Authors: Buckland-Nicks J. , Schander C.
Published: September 2008

Gamete structure and fertilization biology of the white chiton, Stenosemus albus (L., 1767), were studied with light and electron microscopy. Sperm structure was found to be similar to other Chitonina, but acrosomes are homogeneous in this species, like those of Chaetopleura apiculata (Say in Conrad, 1834). The egg of S. albus is covered by long spines with hooked tips. The bases of spines are perforated along their perimeters by a series of pores that provide sperm with direct access to the vitelline layer. This feature appears to be plesiomorphic and characterizes also Chaetopleura but not most Chitonina, which have a continuous dense layer overlying the hull. Beneath the vitelline layer, the egg membrane is formed into a series of cups with raised edges elaborated into microvilli that coincide with the bases of hull spines. Free-spawned sperm of S. albus were able to find the egg and penetrate a pore in the hull within 20 s. Evidence presented here, and previously, indicates that S. albus shares a number of key characters in common with Callochitonidae, which is a basal family within Chitonida. Taken together, the evidence suggests that Stenosemus belongs to a basal taxon within Chitonina, outside the Ischnochitoninae, in which it is currently placed.
The ability of high- and low-grooming lines of honey bees to remove the parasitic mite Varroa destructor is affected by environmental conditions
Authors: Currie R. W. , Tahmasbi G. H.
Published: September 2008

This study assessed how variation in temperature and humidity affect the costs and benefits of grooming as a defense against Varroa destructor Anderson and Trueman, 2000 in high-grooming and low-grooming groups of honey bee (Apis mellifera L., 1758) workers. Grooming was quantified as the proportion of mites falling to the bottom of cages containing worker bees or to the bottom of colonies of bees during winter. Cages of 100 mite-infested bees from each line of workers were assigned to environments with three treatment combinations of temperature (10, 25, and 34 °C) and humidity (low, medium, and high), and bee and mite mortality rates were quantified. The results showed relative effectiveness of high- and low-grooming groups being affected by the environment. Differences in grooming between lines were greatest at 25 °C and were slightly higher under conditions of low humidity than at higher levels. Mite mortality rates were greater in high-grooming groups of caged bees than in low-grooming bees held at 25 and 34 °C but were similar at 10 °C. During winter, colonies with high-grooming bees had higher daily mite mortality rates than unselected colonies. Bee mortality rates were greater in high-grooming lines than in low-grooming lines under low temperatures, indicating that there may be a biological cost associated with grooming behaviour at low temperature.
Experimental trials of the northern flying squirrel (Glaucomys sabrinus) traversing managed rainforest landscapes: perceptual range and fine-scale movements
Authors: Flaherty E. A. , Smith W. P. , Pyare S. , Ben-David M.
Published: September 2008

Successful dispersal in many species may be a function of the distance at which animals can perceive a particular landscape feature (i.e., perceptual range), as well as energetic costs associated with traversing the distance towards that feature. We used a model, relating perceptual range to body size of mammals, to predict the perceptual range of the northern flying squirrel ( Glaucomys sabrinus (Shaw, 1801)) in fragmented forests of Southeast Alaska. We hypothesized that the perceptual range of flying squirrels would be 325.5–356.5 m in clearcuts and 159.7–174.9 m in second-growth stands. The distance advantage in clearcuts may, however, be lost if the cost of transport in that habitat is higher. Our results suggest that as heuristically predicted by the model, the perceptual range of flying squirrels was greater in clearcut habitats than in second-growth stands. Nonetheless, for both habitats the actual perceptual range was significantly shorter than predicted by the model. We found that precipitation, and associated cloud cover and illumination, and wind speed, which affect olfaction capabilities, influenced orientation success. Although squirrels more often oriented towards the forest edge in clearcuts, they paused more often during their movements, which may lead to higher costs of dispersing through this habitat. The application of the mass-based model to nonagricultural landscapes should be done with caution, and variables such as wind and illumination be measured concurrently. Our data illustrate that dispersing squirrels likely will not venture into managed habitats because logging creates clearcuts larger than the perceptual range of these mammals.
Younger bank voles are more vulnerable to avian predation
Authors: Meri Taru , Halonen Matti , Mappes Tapio , Suhonen Jukka
Published: September 2008

The importance of predation on prey populations is mainly determined by the number of eaten prey. However, the total impact of predation might also be determined by the selection of certain prey individuals, e.g., different sexes or age categories. Here we tested selective predation by an avian predator, the pygmy owl ( Glaucidium passerinum (L., 1758)), on bank voles ( Myodes ( Clethrionomys ) glareolus (Schreber, 1780)). We compared the sex, age, and mass of hoarded prey with the animals snap-trapped from the field. There were no differences in the sex ratio between hoarded bank voles and those available in the field. However, hoarded voles were significantly younger than ones in the field sample. There was no statistically significant difference in mass between animals from larders and from the field. We suggest that the greater vulnerability of younger animals to predation might be due to their higher activity, or alternatively, they might be forced to forage in less safe habitats.
QUANTIZATION OF BOSONIC FIELDS WITH TWO MASS AND SPIN STATES
Authors: KRUGLOV S. I.
Published: September 2008

We investigate bosonic fields possessing two mass and spin states. The density matrix in the first-order formalism is obtained. The quantization of fields in the first-order formulation is performed and propagators are found.
ASSESSMENT OF SOME RECENTLY DEVELOPED DENSITY FUNCTIONALS FOR CALCULATIONS ON IRON PORPHYRINS
Authors: LIAO MENG-SHENG , WATTS JOHN D. , HUANG MING-JU
Published: September 2008

The behaviors of several recently developed density functionals (M05, M05-2x, M06, M06-2x, M06-L, KT1, KT2) in describing the spin-state energetics of iron porphyrins [ FeP , FeP ( Cl ), FeP ( THF )2, FeTpivPP ] have been investigated, where KT1 and KT2 are pure GGA (generalized gradient approximation) functionals; M06-L is a meta-GGA functional that contains the kinetic-energy density τ[=∑(∇ϕi)2]; M05, M05-2x, M06, and M06-2x are hybrid meta-GGA functionals that include both the kinetic-energy density and Hartree–Fock exchange. The results reveal that KT1 and KT2 are biased toward lower-spin states and so fail to give the correct ground state for the high-spin systems, but KT2 shows a significant improvement over KT1. M05, M05-2x, M06, and M06-2x yield results which are in qualitative agreement with the experimental findings for FeP ( Cl ) and FeP ( THF )2, but their relative energies for the high-spin states are actually underestimated greatly. Among the various functionals tested here, only M06-L is able to provide a satisfactory description of the energetics of FeP , FeP ( Cl ), and FeP ( THF )2, for which the ground-state multiplicities are surely known. FeTpivPP is predicted to be high spin by the M06-L functional, in agreement with the early experimental magnetic measurement, but different from the previous results (and conclusion) obtained with other various functionals.
BLOCK-LOCALIZED WAVEFUNCTION ENERGY DECOMPOSITION (BLW-ED) ANALYSIS OF σ/π INTERACTIONS IN METAL-CARBONYL BONDING
Authors: NAKASHIMA KAZUHITO , ZHANG XIN , XIANG MINGLI , LIN YUCHUN , LIN MENGHAI , MO YIRONG
Published: September 2008

The bonding features in metal-carbonyls including neutral M CO (M = Ni , Pd , Pt ) and M CO + (M+ = Cu +, Ag +, Au +) complexes have been elucidated at the DFT level with relativistic compact effective potentials for transition metals and 6-311+G(d) basis sets for C and O by the block-localized wavefunction (BLW) method. The BLW method can decompose the intermolecular interactions in terms of Heitler–London, polarization, and charge transfer energy contributions. Since the metal– CO bonding involves two synergic interactions, namely the σ-dative bond from the carbon lone electron pair to an empty d σ orbital on the metal, and the π back-donation from filled d π orbitals to the empty 2π* orbital on CO , the present BLW-ED analyses quantitatively demonstrated that in neutral M CO complexes the π-bonding dominates over the σ-bonding, whereas in cationic M CO + complexes, the σ-bonding plays a major role. But in both neutral and cationic species, the CO polarization induced by the metals enhances the C–O bond and increases the C–O vibrational frequencies, while the π back-donation tends to weaken the C–O bond and decrease the C–O vibrational frequencies. For neutral complexes, the latter is more prominent than the former, and consequently, there is a red-shifting of the C–O vibrational frequencies. In contrast, the π back-donation is insignificant in M CO + cations, and the C–O eventually vibrates at higher frequencies than the free CO frequency.
AN EFFICIENT CRITERION FOR THE FORMATION ENERGIES AND REACTIVITIES OF DEFECTS IN CNTs AND BNNTs
Authors: LI JUNQIAN , CHEN YONG , CHEN LINGANG
Published: September 2008

Directional curvature KD, was proposed as a simple and efficient criterion for the formation energies and reactivities of defects in carbon and boron nitride nanotubes. Using the periodic density functional theory, the formation energies of Stone–Wales (SW) and divacancy (DV) defects in their armchair (5,5) and zigzag (10,0) nanotubes, as well as the binding energies of the O atom adducts on these defect sites are calculated. These calculated results are found to fit well with the theoretical predictions by the directional curvature KD.
Complexity results for security protocols with Diffie-Hellman exponentiation and commuting public key encryption
Authors: Chevalier Yannick , Küsters Ralf , Rusinowitch Michaël , Turuani Mathieu
Published: September 2008

We show that the insecurity problem for protocols with modular exponentiation and arbitrary products allowed in exponents is NP-complete. This result is based on a protocol and intruder model which is powerful enough to uncover known attacks on the Authenticated Group Diffie-Hellman (A-GDH.2) protocol suite. To prove our results, we develop a general framework in which the Dolev-Yao intruder is extended by generic intruder rules. This framework is also applied to obtain complexity results for protocols with commuting public key encryption.
Transcriptional Control of Skeletogenesis
Authors: Karsenty Gerard
Published: September 2008

The skeleton contains three specific cell types: chondrocytes in cartilage and osteoblasts and osteoclasts in bone. Our understanding of the transcriptional mechanisms that lead to cell differentiation along these three lineages has increased considerably in the past ten years. In the case of chondrocytes and osteoblasts advances have been made possible largely through the molecular elucidation of human skeletal dysplasias. This review discusses the key transcription factors that regulate skeletogenesis and highlights their function, mode of action, and regulation by other factors, with a special emphasis on how human genetics has contributed to this knowledge.
Activation of the oxygen-sensing signal cascade prevents mitochondrial injury after mouse liver ischemia-reperfusion
Authors: Zhong Zhi , Ramshesh Venkat K. , Rehman Hasibur , Currin Robert T. , Sridharan Vijayalakshmi , Theruvath Tom P. , Kim Insil , Wright Gary L. , Lemasters John J.
Published: September 2008

The mitochondrial permeability transition (MPT) plays an important role in hepatocyte death caused by ischemia-reperfusion (IR). This study investigated whether activation of the cellular oxygen-sensing signal cascade by prolyl hydroxylase inhibitors (PHI) protects against the MPT after hepatic IR. Ethyl 3,4-dihyroxybenzoate (EDHB, 100 mg/kg ip), a PHI, increased mouse hepatic hypoxia-inducible factor-1α and heme oxygenase-1 (HO-1). EDHB-treated and untreated mice were subjected to 1 h of warm ischemia to ∼70% of the liver followed by reperfusion. Mitochondrial polarization, cell death, and the MPT were assessed by intravital confocal/multiphoton microscopy of rhodamine 123, propidium iodide, and calcein. EDHB largely blunted alanine aminotransferase (ALT) release and necrosis after reperfusion. In vehicle-treated mice at 2 h after reperfusion, viable cells with depolarized mitochondria were 72%, and dead cells were 2%, indicating that depolarization preceded necrosis. Mitochondrial voids excluding calcein disappeared, indicating MPT onset in vivo. NIM811, a specific inhibitor of the MPT, blocked mitochondrial depolarization after IR, further confirming that mitochondrial depolarization was due to MPT onset. EDHB decreased mitochondrial depolarization to 16% and prevented the MPT. Tin protoporphyrin (10 μmol/kg sc), an HO-1 inhibitor, partially abrogated protection by EDHB against ALT release, necrosis, and mitochondrial depolarization. In conclusion, IR causes the MPT and mitochondrial dysfunction, leading to hepatocellular death. PHI prevents MPT onset and liver damage through an effect mediated partially by HO-1.
The role of Sp1 in IL-1β andH. pylori-mediated regulation of H,K-ATPase gene transcription
Authors: Saha Arindam , Hammond Charles E. , Gooz Monika , Smolka Adam J.
Published: September 2008

Helicobacter pylori infection of the gastric body induces transient hypochlorhydria and contributes to mucosal progression toward gastric carcinoma. Acid secretion is mediated by parietal cell H,K-ATPase, in which the catalytic α-subunit (HKα) promoter activity in transfected gastric epithelial [gastric adenocarcinoma (AGS)] cells is repressed by H. pylori through NF-κB p50 homodimer binding to the promoter. IL-1β, an acid secretory inhibitor whose mucosal level is increased by H. pylori, upregulates HKα promoter activity in AGS cells. Because IL-1β also activates NF-κB signaling, we investigated disparate HKα regulation by H. pylori and IL-1β, testing the hypothesis that IL-1β-induced HKα promoter activation is mediated by the transcription factor Sp1. DNase I footprinting revealed Sp1 binding to the HKα promoter at −56 to −39 bp. IL-1β stimulated the activity of three HKα promoter constructs containing NF-κB and Sp1 sites transfected into AGS cells and also stimulated a construct containing only an Sp1 site. This stimulation was abrogated by mutating the HKα promoter Sp1 binding site. Gelshift assays showed that IL-1β increased Sp1 but not p50 binding to cognate HKα probes and that Sp1 also interacts with an HKα NF-κB site when bound to its cognate HKα cis-response element. H. pylori did not augment Sp1 binding to an HKα Sp1 probe, and small interfering RNA-mediated knockdown of Sp1 expression abrogated IL-1β-induced HKα promoter stimulation. We conclude that IL-1β upregulates HKα gene transcription by inducing Sp1 binding to HKα Sp1 and NF-κB sites and that the H. pylori perturbation of HKα gene expression is independent of Sp1-mediated basal HKα transcription.
Thrombin mediates the extraintestinal thrombosis associated with experimental colitis
Authors: Yoshida Hideo , Russell Janice , Granger D. Neil
Published: September 2008

Recent evidence implicating tissue factor and the protein C pathway in the hypercoagulable state associated with intestinal inflammation suggests that thrombin is likely to contribute to this response. The objective of this study was to assess the role of thrombin in the extraintestinal thrombosis associated with experimental colitis. Thrombus formation was quantified in microvessels of the cremaster muscle in mice with dextran sodium sulfate (DSS)-induced colonic inflammation. The light/dye endothelial injury model was used to elicit thrombus formation in DSS colitic mice treated with either hirudin, heparin, or antithrombin III. The initiation and propagation/stabilization phases of thrombus formation were quantified using the time of onset of the thrombus and time to blood flow cessation, respectively. Thrombus formation was accelerated in arterioles of DSS colitic mice, as exhibited by significant reductions in the time of thrombus initiation and propagation/stabilization. Colitic mice treated with hirudin, heparin, or antithrombin III did not exhibit a significant change in the time of onset of the thrombus compared with untreated colitic mice. However, all three antithrombin agents largely prevented the DSS-induced reduction in the time to flow cessation following light/dye injury, with hirudin offering complete protection. These findings indicate that thrombin plays a major role in the extraintestinal thrombus formation associated with experimental colitis. Thrombin appears to contribute to the propagation/stabilization, rather than initiation, phase of the colitis-associated thrombogenesis at the distant vascular site. The results support the therapeutic use of antithrombin agents for reducing the risk of thromboembolism in patients with inflammatory bowel disease.
The beginning of a fantastic, unanswered question: is 5-HT involved in systemic hypertension?
Authors: Watts Stephanie W.
Published: September 2008

This essay examines the historical significance of an APS classic paper that is freely available online:

McGregor DD, Smirk FH. Vascular responses to 5-hydroxytryptamine in genetic and renal hypertensive rats. Am J Physiol 219: 687–690, 1970. ( http://ajplegacy.physiology.org/cgi/reprint/219/3/687 )
DSCF Neurons Within the Primary Auditory Cortex of the Mustached Bat Process Frequency Modulations Present Within Social Calls
Authors: Washington Stuart D. , Kanwal Jagmeet S.
Published: September 2008

Neurons in the Doppler-shifted constant frequency processing (DSCF) area in the primary auditory cortex of mustached bats, Pteronotus parnellii, are multifunctional, responding both to echolocation and communication sounds. Simultaneous presentation of a DSCF neuron's best low and high frequencies (BFlow and BFhigh, respectively) facilitates its response. BFlow corresponds to a frequency in the frequency-modulated (FM) component of the first harmonic in the echolocation pulse, and BFhigh corresponds to the constant frequency (CF) component in the second harmonic of the echo. We systematically varied the slopes, bandwidths, and central frequencies of FMs traversing the BFhigh region to arrive at the “best FM” for single DSCF neurons. We report that nearly half (46%) of DSCF neurons preferred linear FMs to CFs and average response magnitude to FMs was not significantly less ( P = 0.08) than that to CFs at BFhigh when each test stimulus was paired with a CF at BFlow. For linear FMs ranging in slope from 0.04 to 4.0 kHz/ms and in bandwidth from 0.44 to 7.88 kHz, the majority of DSCF neurons preferred upward (55%) to downward (21%) FMs. Central frequencies of the best FMs were typically close to but did not always match a neuron's BFhigh. Neurons exhibited combination-sensitivity to “call fragments” (calls that were band-pass filtered in the BFhigh region) paired with their BFlow. Our data show a close match between the modulation direction of a neuron's best FM and that of its preferred call fragment. These response properties show that DSCF neurons extract multiple parameters of FMs and are specialized for processing both FMs for communication and CFs for echolocation.
Cross‐Slot Antenna with U‐Shaped Tuning Stub for Ultra‐Wideband Applications
Authors: Javan Dawood Seyed , Salari Mohammad Ali , Ghoochani Omid Hashemi
Published: September 2008

A novel design of an ultra‐wideband (UWB) slot antenna is presented. This antenna operates as a transmitter and receiver antenna. Effects of the antenna dimensional parameters are studied through experimental and simulation results. Design procedures are developed and verified for different frequency bands. The experimental and simulation results exhibit good impedance bandwidth, radiation pattern, and relatively constant gain over the entire band of frequency. Antenna gain and directivity at boresight and in their maximum states are close to each other and indicate high radiation efficiency. To use the antenna as a linearly polarized antenna, the radiation pattern in E‐plane is better than that in H‐plane.
Assessment of a PML Boundary Condition for Simulating an MRI Radio Frequency Coil
Authors: Duan Yunsuo , Ibrahim Tamer S. , Peterson Bradley S. , Liu Feng , Kangarlu Alayar
Published: September 2008

Computational methods such as the finite difference time domain (FDTD) play an important role in simulating radiofrequency (RF) coils used in magnetic resonance imaging (MRI). The choice of absorbing boundary conditions affects the final outcome of such studies. We have used FDTD to assess the Berenger′s perfectly matched layer (PML) as an absorbing boundary condition for computation of the resonance patterns and electromagnetic fields of RF coils. We first experimentally constructed a high‐pass birdcage head coil, measured its resonance pattern, and used it to acquire proton ( 1H) phantom MRI images. We then computed the resonance pattern and B1 field of the coil using FDTD with a PML as an absorbing boundary condition. We assessed the accuracy and efficiency of PML by adjusting the parameters of the PML and comparing the calculated results with measured ones. The optimal PML parameters that produce accurate (comparable to the experimental findings) FDTD calculations are then provided for the birdcage head coil operating at 127.72 MHz, the Larmor frequency of  1H at 3 Tesla (T).
Depletion of Dendritic Cells Delays Ovarian Cancer Progression by Boosting Antitumor Immunity
Authors: Huarte Eduardo , Cubillos-Ruiz Juan R. , Nesbeth Yolanda C. , Scarlett Uciane K. , Martinez Diana G. , Buckanovich Ronald J. , Benencia Fabian , Stan Radu V. , Keler Tibor , Sarobe Pablo , Sentman Charles L. , Conejo-Garcia Jose R.
Published: September 2008

Dendritic cells (DC) and cytokines that expand myeloid progenitors are widely used to treat cancer. Here, we show that CD11c+DEC205+ DCs coexpressing α-smooth muscle actin and VE-cadherin home to perivascular areas in the ovarian cancer microenvironment and are required for the maintenance of tumor vasculature. Consequently, depletion of DCs in mice bearing established ovarian cancer by targeting different specific markers significantly delays tumor growth and enhances the effect of standard chemotherapies. Tumor growth restriction was associated with vascular apoptosis after DC ablation followed by necrosis, which triggered an antitumor immunogenic boost. Our findings provide a mechanistic rationale for selectively eliminating tumor-associated leukocytes to promote antitumor immunity while impeding tumor vascularization and to develop more effective DC vaccines based on a better understanding of the tumor microenvironment. [Cancer Res 2008;68(18):7684–91]
Combinations ofN-Acetyl-S-(N-2-Phenethylthiocarbamoyl)-L-Cysteine andmyo-Inositol Inhibit Tobacco Carcinogen–Induced Lung Adenocarcinoma in Mice
Authors: Kassie Fekadu , Matise Ilze , Negia Mesfin , Lahti David , Pan Yunqian , Scherber Robyn , Upadhyaya Pramod , Hecht Stephen S.
Published: September 2008

We have previously generated convincing evidence that combinations of N-acetyl-S-(N-2-phenethylthiocarbamoyl)-L-cysteine (PEITC-NAC; 3 μmol/g diet) and myo-inositol (MI; 56 μmol/g diet) were significantly more effective than the individual compounds as inhibitors of tobacco smoke carcinogen–induced lung tumorigenesis in A/J mice. In this study, we further investigated the efficacy of combinations of PEITC-NAC (9 or 15 μmol/g diet) and MI (56 μmol/g diet). Female A/J mice were treated with a mixture of the tobacco smoke carcinogens 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone and benzo[a]pyrene by gavage once weekly for 8 weeks. PEITC-NAC plus MI was given in the diet beginning at 1 day after the 4th of eight carcinogen treatments (temporal sequence A) or 1 week after the last carcinogen treatment (temporal sequence B). Regardless of the dose of carcinogen or PEITC-NAC plus MI, or temporal sequence, administration of PEITC-NAC plus MI significantly reduced the multiplicity of gross tumors and, in most instances, adenocarcinoma. PEITC-NAC plus MI was particularly effective against bigger tumors. The observed inhibition of lung tumorigenesis by PEITC-NAC plus MI was attributed, at least partly, to inhibition of cell proliferation and induction of apoptosis. These results clearly show the efficacy of PEITC-NAC plus MI in the prevention of tobacco carcinogen–induced lung adenocarcinoma in A/J mice and provide a basis for future evaluation of PEITC-NAC plus MI in clinical trials as a chemopreventive agent for current and former smokers.
Ninein Is Expressed in the Cytoplasm of Angiogenic Tip-Cells and Regulates Tubular Morphogenesis of Endothelial Cells
Authors: Matsumoto Taro , Schiller Petter , Dieterich Lothar C. , Bahram Fuad , Iribe Yuji , Hellman Ulf , Wikner Charlotte , Chan Gordon , Claesson-Welsh Lena , Dimberg Anna
Published: September 2008

Objective—

Angiogenesis is an integral part of many physiological processes but may also aggravate pathological conditions such as cancer. Development of effective angiogenesis inhibitors requires a thorough understanding of the molecular mechanisms regulating vessel formation. The aim of this project was to identify proteins that regulate tubular morphogenesis of endothelial cells.

Methods and Results—

Phosphotyrosine-dependent affinity-purification and mass spectrometry showed tyrosine phosphorylation of ninein during tubular morphogenesis of endothelial cells. Ninein was recently identified as a centrosomal microtubule-anchoring protein. Our results show that ninein is localized in the cytoplasm in endothelial cells, and that it is highly expressed in the vasculature in normal and pathological human tissues. Using embryoid bodies as a model of vascular development, we found that ninein is abundantly expressed in the cytoplasm of endothelial cells during sprouting angiogenesis, in particular in the sprouting tip-cell. In accordance, siRNA-dependent silencing of ninein in endothelial cells inhibited tubular morphogenesis.

Conclusions—

In this study, we show that ninein is expressed in developing vessels and in endothelial tip cells, and that ninein is critical for formation of the vascular tube. These data strongly implicate ninein as an important new regulator of angiogenesis.
Vascular Inflammation, Insulin Resistance, and Reduced Nitric Oxide Production Precede the Onset of Peripheral Insulin Resistance
Authors: Kim Francis , Pham Matilda , Maloney Ezekiel , Rizzo Norma O. , Morton Gregory J. , Wisse Brent E. , Kirk Elizabeth A. , Chait Alan , Schwartz Michael W.
Published: September 2008

Objectives—

Obesity causes inflammation and insulin resistance in the vasculature as well as in tissues involved in glucose metabolism such as liver, muscle, and adipose tissue. To investigate the relative susceptibility of vascular tissue to these effects, we determined the time course over which inflammation and insulin resistance develops in various tissues of mice with diet-induced obesity (DIO) and compared these tissue-based responses to changes in circulating inflammatory markers.

Methods and Results—

Adult male C57BL/6 mice were fed either a control low-fat diet (LF; 10% saturated fat) or a high-fat diet (HF, 60% saturated fat) for durations ranging between 1 to 14 weeks. Cellular inflammation and insulin resistance were assessed by measuring phospho-IκBα and insulin-induced phosphorylation of Akt, respectively, in extracts of thoracic aorta, liver, skeletal muscle, and visceral fat. As expected, HF feeding induced rapid increases of body weight, fat mass, and fasting insulin levels compared to controls, each of which achieved statistical significance within 4 weeks. Whereas plasma markers of inflammation became elevated relatively late in the course of DIO (eg, serum amyloid A [SAA], by Week 14), levels of phospho-IκBα in aortic lysates were elevated by 2-fold within the first week. The early onset of vascular inflammation was accompanied by biochemical evidence of both endothelial dysfunction (reduced nitric oxide production; induction of intracellular adhesion molecule-1 and vascular cell adhesion molecule-1) and insulin resistance (impaired insulin-induced phosphorylation of Akt and eNOS). Although inflammation and insulin resistance were also detected in skeletal muscle and liver of HF-fed animals, these responses were observed much later (between 4 and 8 weeks of HF feeding), and they were not detected in visceral adipose tissue until 14 weeks.

Conclusions—

During obesity induced by HF feeding, inflammation and insulin resistance develop in the vasculature well before these responses are detected in muscle, liver, or adipose tissue. This observation suggests that the vasculature is more susceptible than other tissues to the deleterious effects of nutrient overload.
Focal Fluid-Attenuated Inversion Recovery Hyperintensity Within Acute Diffusion-Weighted Imaging Lesions Is Associated With Symptomatic Intracerebral Hemorrhage After Thrombolysis
Authors: Cho A-Hyun , Kim Jong S. , Kim Sang-Joon , Yun Sung-Cheol , Choi Choong-Gon , Kim Hyoung-Ryoul , Kwon Sun U. , Lee Deok-Hee , Kim Eun-Kyung , Suh Dae-Chul , Kang Dong-Wha
Published: September 2008

Background and Purpose—

We investigated whether focal hyperintensity on fluid-attenuated inversion recovery image within acute infarcts is associated with symptomatic intracerebral hemorrhage (SICH) after thrombolysis.

Methods—

Patients with acute ischemic stroke who underwent MRI screening before thrombolysis were enrolled. The presence of focal fluid-attenuated inversion recovery hyperintensity within acute infarcts did not preclude thrombolysis. SICH was defined as hemorrhagic transformation with any neurological decline (SICH-1) or with an increase in National Institutes of Health Stroke Scale of ≥4 (SICH-2) within 48 hours.

Results—

Among 88 included patients, focal fluid-attenuated inversion recovery hyperintensity within acute infarct lesions was observed in 27 (30.7%) patients. Multivariate analysis showed that focal fluid-attenuated inversion recovery hyperintensity was independently associated with SICH-1 (OR, 13.64; 95% CI, 1.51 to 123.28) and SICH-2 (OR, 10.44; 95% CI, 1.11 to 98.35).

Conclusion—

The presence of focal fluid-attenuated inversion recovery hyperintensity within acute infarcts may increase the risk of symptomatic intracerebral hemorrhage after thrombolysis.
Deriving Modified Rankin Scores From Medical Case-Records
Authors: Quinn Terence J. , Ray Gautamananda , Atula Sari , Walters Matthew R. , Dawson Jesse , Lees Kennedy R.
Published: September 2008

Background and Purpose—

Modified Rankin score (mRS) is traditionally graded using a face-to-face or telephone interview. Certain stroke assessment scales can be derived from a review of a patient’s case-record alone. We hypothesized that mRS could be successfully derived from the narrative within patient case-records.

Methods—

Sequential patients attending our cerebrovascular outpatient clinic were included. Two independent, blinded clinicians, trained in mRS, assessed case-records to derive mRS. They scored “certainty” of their grading on a 5-point Likert scale. Agreement between derived and traditional face-to-face mRS was calculated using attribute agreement analysis.

Results—

Fifty patients with a range of disabilities were included. Case-record appraisers were poor at deriving mRS (
k
=0.34 against standard). Derived mRS grades showed poor agreement between observers (
k
=0.33). There was no relationship between certainty of derived mRS and proportion of correct grades (
P
=0.727).

Conclusion—

Accurate mRS cannot be derived from standard hospital records. Direct mRS interview is still required for clinical trials.
Cerebral Ischemia Mediates the Effect of Serum Uric Acid on Cognitive Function
Authors: Vannorsdall Tracy D. , Jinnah H.A. , Gordon Barry , Kraut Michael , Schretlen David J.
Published: September 2008

Background and Purpose—

High normal concentrations of serum uric acid (UA) are associated with mild cognitive dysfunction and increased cerebral ischemia as indexed by white matter hyperintensity volumes. We hypothesized that individual differences in white matter hyperintensities mediate the association between UA and mild cognitive dysfunction.

Methods—

One hundred eighty community-dwelling adults aged 20 to 96 years completed neuropsychological testing, laboratory blood studies, and a brain MRI scan.

Results—

Serum UA was associated (
P
<0.05) with greater white matter hyperintensities and poorer working memory, processing speed, fluency, and verbal memory. Associations remained after controlling for age, sex, race, education, hypertension, diabetes, alcohol abuse, smoking, and body mass. Adding a term for white matter hyperintensity attenuated these associations such that UA no longer predicted cognitive performance.

Conclusions—

Severity of cerebral ischemia might mediate the association between UA and cognitive dysfunction. Even mild elevations in UA appear to contribute to structural and functional brain changes.
Inertially Induced Connections between Subgyres in the South Indian Ocean
Authors: Palastanga V. , Dijkstra H. A. , de Ruijter W. P. M.
Published: September 2008

A barotropic shallow-water model and continuation techniques are used to investigate steady solutions in an idealized South Indian Ocean basin containing Madagascar. The aim is to study the role of inertia in a possible connection between two subgyres in the South Indian Ocean. By increasing inertial effects in the model, two different circulation regimes are found. In the weakly nonlinear regime, the subtropical gyre presents a recirculation cell in the southwestern basin, with two boundary currents flowing westward from the southern and northern tips of Madagascar toward Africa. In the highly nonlinear regime, the inertial recirculation of the subtropical gyre is found to the east of Madagascar, while the East Madagascar Current overshoots the island’s southern boundary and connects through a southwestward jet with the current off South Africa.
Overcoming the risks of restructuring through the integrative bargaining process: Two case studies in a French context
Authors: Garaudel Pierre , Noël Florent , Schmidt Géraldine
Published: September 2008

In this article we analyse two French restructuring cases, using Walton and McKersie's theoretical framework, and provide evidence of the potential of integrative bargaining in restructuring. We argue that any restructuring situation, even in an unfavourable context such as the French, displays an integrative potential, in that employers' and employees' risks are closely interrelated and these risks can be successfully addressed in a cooperative way. The two cases are from widely contrasting contexts: a medium-sized firm in the declining textile industry, and a large insurance company with no short-term economic threat. We show to what extent the underlying bargaining processes are illustrative of an integrative approach as defined by Walton and McKersie and that such an approach may prevail in different kinds of situation, decline-related as well as competition-enhancing restructurings. Moreover, in reference with the four sub-processes developed in the Walton and MacKersie's model, we analyse how and under which conditions, an integrative approach can be achieved. Finally, we discuss theoretical implications concerning the application of this model to restructuring processes.
Are Labour Markets Necessarily 'Local'? Spatiality, Segmentation and Scale
Authors: Weller Sally A.
Published: September 2008

This paper draws on recent debates about scale to approach the geography of labour markets from a dynamic perspective sensitive to the spatiality and scale of labour market restructuring. Its exploration of labour market reconfigurations after the collapse of a major firm (Ansett Airlines) raises questions about geography's faith in the inherently `local' constitution of labour markets. Through an examination of the job reallocation process after redundancy, the paper suggests that multiple labour markets use and articulate scale in different ways. It argues that labour market rescaling processes are enacted at the critical moment of recruitment, where social networks, personal aspirations and employer preferences combine to shape workers' destinations.
Rethinking Urban Projects: Experiences in Europe
Authors: Salet Willem
Published: September 2008

This article investigates how decision-making processes relating to strategic urban projects are framed in order to achieve innovative urban developments. Three dimensions of framing are analysed: the cognitive framing, the framing of alliances in the metroplitan action space and the framing of the democratic process. The crux for success is in organising interconnectivity between the dimensions of framing in a multi-actor and multilevel context. The model's assumptions are tested by an application to four of Europe's largest urban projects under construction.