bluuebunny/crossref_metadata_2025 huggingface dataset:
Resolving multiple goal conflicts with interactive goal programming
Authors: Rustagi Krishna P. , Bare B. Bruce
Published: April 2008

A two-phase interactive goal programming procedure is described, which is potentially useful for resolving multiple-use conflicts where multiple and conflicting objectives exist. In the analytical phase, the procedure locates efficient solutions that are proportionally equidistant from the established goal targets. In the decision phase, these results are presented to the decision maker who either accepts the compromise solution provided by the analyst or revises the goal targets and enters into another iteration. The important features of the procedure are (i) the decision maker is not required to explicitly specify any weights or utility function to express preference among objectives; (ii) the results of each iteration are presented to the decision maker graphically, using value paths to allow easy visualization of the extent of compatibility or conflict among the different objectives; and (iii) the analyst explores efficient basic as well as nonbasic solutions in search of the best compromise solution. An illustrative example is included to demonstrate the application of the procedure.
Nitrogen dynamics in conifer-dominated forests with and without hardwoods
Authors: Perry D. A. , Choquette C. , Schroeder P.
Published: April 2008

Nitrogen and carbon in the surface 12 cm of mineral soil, N in leaf litterfall, anaerobic N mineralization rates in the soil and forest floor, and root and N accretion to sand traps placed in surface soil layers were compared in forests with hardwoods either completely or partially removed during a conifer thinning 3 years before. An adjacent unthinned conifer–hardwood stand was also included. Conifer stocking did not differ between thinned stands with and without hardwoods. Stands without hardwoods averaged 520 kg/ha more N in mineral soil (p < 0.001), 20% more N mineralized from soil during 7-day incubations (p < 0.001), and lower soil C:N ratio (p = 0.02) than stands with hardwoods. These variables did not differ between thinned and unthinned mixed stands. Soil N did not correlate with the number of hardwoods removed. Weight of forest floor and rate of N mineralization from the forest floor did not differ between mixed and pure stands. However, stands with hardwoods returned about 10 kg•ha−1•year−1 more N in leaf litter (due to higher N concentration in conifer litter as well as the presence of high-N hardwood litter); stands without hardwoods accreted about 10 kg•ha−1•year−1 more N in sand traps. Soil N mineralization in mixed stands correlated positively with N mineralization in the forest floor but not with N accretion to sand traps, while the opposite was true in pure conifer stands. Although pretreatment variability among stands cannot be ruled out, the replicated treatments within a relatively uniform area make it appear likely that differences were related to the presence or absence of hardwoods. This was not a simple additive effect, however, but a community-level phenomenon, that is, conifers cycled N differently when mixed with hardwoods than when in pure stands.
Interaction effects of vegetation type and Pacific madrone soil inocula on survival, growth, and mycorrhiza formation of Douglas-fir
Authors: Amaranthus M. P. , Perry D. A.
Published: April 2008

Douglas-fir seedlings were planted in cleared blocks within three adjacent vegetation types, whiteleaf manzanita, annual grass meadow, and an open stand of Oregon white oak, in southwest Oregon. Within subplots in each block, either pasteurized or unpasteurized soil from a nearby Pacific madrone stand was transferred to the planting holes of the seedlings; control seedlings received no madrone soil. Second-year survival averaged 92, 43, and 12% for seedlings planted on the manzanita, meadow, and oak sites, respectively. Growth differences generally paralleled survival differences. Added madrone soil, whether pasteurized or unpasteurized, did not influence survival, but growth of seedlings on the manzanita site was substantially increased by the addition of unpasteurized madrone soil. Unpasteurized madrone soil did not influence growth of seedlings in the meadow and the oak stand. Pasteurized madrone soil did not affect growth in any of the vegetation types. When added to the manzanita site, unpasteurized madrone soil nearly tripled the number of mycorrhizal root tips forming on seedlings and resulted in formation of a new mycorrhiza type not seen otherwise. As with growth, unpasteurized madrone soil had little or no effect in the other vegetation types. These results suggest that manzanita and madrone impose on soils a biological pattern that stimulates Douglas-fir growth and survival, and they add to the growing body of literature showing that root symbionts and rhizosphere organisms mediate interactions among plant species.
The relationship between gross crown dimensions and sapwood area at crown base in Douglas-fir
Authors: Maguire Douglas A. , Hann David W.
Published: April 2008

Crown dimensions and sapwood area near crown base were measured on 189 Douglas-fir trees in southwestern Oregon. Sapwood areas were interpolated or extrapolated to crown base with a sapwood taper function. Various transformations of crown length and crown radius (as well as crown base stem diameter as a surrogate for crown diameter) were assessed for their ability to predict crown base sapwood area. Regression analyses indicated that no single untransformed variable was a good predictor of sapwood area at crown base, but that combinations representing conic surface area performed quite well. Given the consistently strong relationship between total leaf area and sapwood area at crown base, conic surface area should accurately reflect total leaf area and relative photosynthetic potential of the tree. Gross crown dimensions and crown base sapwood area prove complementary in a forest modeling context, owing to the structural appeal of the former and the physiological appeal of the latter.
Radial trends in cation ratios in tree rings as indicators of the impact of atmospheric deposition on forests
Authors: Bondietti E. A. , Baes III C. F. , McLaughlin S. B.
Published: April 2008

Concentration ratios of aluminum to calcium, magnesium, and other divalent cations in increment cores obtained from red spruce and eastern hemlock trees growing in the Great Smoky Mountains National Park in Tennessee and North Carolina have increased in an unprecedented manner during the last 15–40 years. These trends, which also occur in other trees growing in eastern North America and Germany may reflect the mobilization of exchangeable aluminum by [Formula: see text] and [Formula: see text] deposition. The soil chemistry and plant physiology bases for this hypothesis are presented. Many of the spruce and hemlock cores from the Great Smoky Mountains also showed an inverse relationship between radial growth and aluminium:alcium ratios in the wood. Changes in the availability of soil cations, as recorded in tree rings, may provide an ecosystem-level method of evaluating the historical response of forest soils to atmospheric deposition.
Deep tritiated water uptake and predawn xylem water potentials as indicators of vertical rooting extent in a Quercus–Carya forest
Authors: Stringer Jeffrey W. , Kalisz Paul J. , Volpe John A.
Published: April 2008

Transpiration uptake from a tritiated water source (3H2O) associated with a sandstone bed at 3 m depth was examined in a second-growth Quercus–Carya forest. The effect of utilization of deep water on predawn xylem water potentials (Pstem) was also investigated. The 3H2O saturated the soil contacting the sandstone bed. As surface soils dried during the growing season, 3H2O uptake increased. Although all trees growing over the 3H2O reserve were capable of utilizing some of this water, Q. alba trees from all canopy levels generally exhibited higher foliage tritium (3H) activities than C. glabra (Mill.) Sweet. Higher (less negative) Pstem values were associated with trees having higher foliage 3H activities. The Q. alba tree with the highest foliage 3H activity, 1.2 × 106 Bq•L−1, exhibited the highest Pstem value, −0.875 MPa; the Q. alba tree with the lowest 3H activity also had the lowest Pstem value, 4.5 × 104 Bq•L−1 and −1.75 MPa, respectively. Pstem and the logarithm of 3H activity were highly correlated (r2 = 0.89), suggesting that predawn moisture status was at least partially controlled by the ability of trees to utilize the deep water reserve at or near the fractured sandstone bed.
Causality in mortality patterns of spruce trees during a spruce budworm outbreak
Authors: Osawa Akira
Published: April 2008

Patterns of tree mortality in the species complex of red spruce (Picearubens Sarg.), black spruce (Piceamariana (Mill.) B.S.P.) and their possible hybrids that developed during a spruce budworm (Choristoneurafumiferana (Clem.)) outbreak in Maine, U.S.A., were analyzed in relation to five hypotheses of their causal mechanisms. The observed patterns of spruce mortality were primarily a result of the phenotypic variation among the spruces. Close relationships among the mean hybrid index of spruce trees in a plot and such stand variables as balsam fir (Abiesbalsamea (L.) Mill.) basal area and drainage index are likely to have created coincidental correlations between tree mortality and those variables that do not necessarily reflect causality.
Structural change and factor demand in Montana's solid wood products industries
Authors: Wear David N.
Published: April 2008

This paper introduces a methodology for testing for structural changes in wood products industries, using derived demand equations and out of sample forecasts. In an application to Montana's solid wood products industries, labor and stumpage demand functions estimated from 1958–1978 data err significantly in predicting 1985 observations. A reasonable conclusion from the analysis is that structural change has occurred since 1978, probably during the 1979–1983 downturn in wood products markets. An apparent increase in production efficiency and a decrease in the use of labor have implications for public land management in the state.
MSLS: a linear least squares technique for fitting a simultaneous system of equations with a generalized error structure
Authors: LeMay Valerie M.
Published: April 2008

Forestry problems are frequently represented by a system of equations rather than a single equation. Many authors have used the two- and three-stage least squares (2SLS and 3SLS) and seemingly unrelated regressions techniques of econometrics to estimate the coefficients of these forestry systems. The assumption in using these techniques is that the error terms of individual equations are independent and identically distributed (iid), even though the equations may be contemporaneously correlated. For forestry systems, this assumption is frequently not met. The results are that the estimated variances of the coefficients are statistically biased and not consistent, and confidence intervals for the estimated coefficients and mean predicted values are inaccurate. The multistage least squares (MSLS) technique presented in this paper relaxes this iid assumption by extending 3SLS to a more generalized error structure. MSLS is a linear least squares technique that will result in consistent estimates of the coefficients and their associated variances. The error covariance matrix of the system of equations is estimated as the product of transformation matrices for each equation and an estimate of the contemporaneous covariance matrix of the system. The estimated coefficients will be asymptotically normally distributed. The limitations to the MSLS technique are that equations of the system must be linear and sample sizes must be equal for all equations. In addition, large sizes are required to calculate confidence intervals and to test hypothesis statements. The MSLS technique is demonstrated using a tree volume estimation example.
Waterlogging tolerance of roots of Sitka spruce clones and of strands from Thelephoraterrestris mycorrhizas
Authors: Coutts M. P. , Nicoll B. C.
Published: April 2008

Rooted cuttings of three clones of Sitka spruce (Piceasitchensis (Bong.) Carr.) were grown in 2 m tall transparent acrylic tubes of peat in insulated boxes out of doors. Roots of many of the trees formed mycorrhizas with Thelephoraterrestris Ehrh.:Fr.; the extra-matrical mycelium and associated strands were visible in the tubes, together with the roots. Some of the tubes were waterlogged to submerge the lower part of the root and mycelial systems. Waterlogging was carried out in October, when roots were growing slowly, or in November, when growth had stopped. The fungal mycelium was growing on both occasions. The tubes were drained in the following March, and survival of main roots and fungus was measured to the point of regeneration. There were large differences between the two waterlogging treatments in root survival. October waterlogging caused substantial dieback, and roots survived to a mean depth of only 122 mm below the water table. November waterlogging resulted in little dieback, and survival depth was 308 mm. Differences between clones in root survival were statistically significant but small. The extra-matrical hyphae of Tterrestris died in both treatments, but all of the strand systems survived and regenerated in the following spring. Factors affecting survival are discussed, including growth and oxygen transport in roots and fungal strands.
An examination of spacing indices for Eucalyptusgrandis
Authors: Bredenkamp Brian V. , Burkhart Harold E.
Published: April 2008

Data from three replications of a correlated curve trend experiment in Eucalyptusgrandis (Hill) Maiden were used to compare spacing indices developed by Reineke (stand density index), O'Connor (S-curve), Yoda (−3/2 power law), and Hart (relative spacing). The experiment tested 12 stand densities ranging from 25 to 6726 stems per hectare, and frequent repeat measurements to age 33 were available. Only data from treatments with stand densities greater than 124 stems per hectare and older than 10 years were included in the study to ensure all stands were approaching a limiting density. Relationships between the indices are developed, and it is shown that they are not independent of age. It is concluded that relative spacing is a useful measure of stand density as both site index and age are incorporated. A value of 0.05 for relative spacing is found as the limiting stand density for E. grandis.
ASSOCIATIVE MEMORY IN QUATERNIONIC HOPFIELD NEURAL NETWORK
Authors: ISOKAWA TEIJIRO , NISHIMURA HARUHIKO , KAMIURA NAOTAKE , MATSUI NOBUYUKI
Published: April 2008

Associative memory networks based on quaternionic Hopfield neural network are investigated in this paper. These networks are composed of quaternionic neurons, and input, output, threshold, and connection weights are represented in quaternions, which is a class of hypercomplex number systems. The energy function of the network and the Hebbian rule for embedding patterns are introduced. The stable states and their basins are explored for the networks with three neurons and four neurons. It is clarified that there exist at most 16 stable states, called multiplet components, as the degenerated stored patterns, and each of these states has its basin in the quaternionic networks.
DECAY PROPERTY OF REGULARITY-LOSS TYPE FOR DISSIPATIVE TIMOSHENKO SYSTEM
Authors: IDE KENTARO , HARAMOTO KAZUO , KAWASHIMA SHUICHI
Published: April 2008

We study the decay property of the dissipative Timoshenko system in the one-dimensional whole space. We derive the L2 decay estimates of solutions in a general situation and observe that this decay structure is of the regularity-loss type. Also, we give a refinement of these decay estimates for some special initial data. Moreover, under enough regularity assumption on the initial data, we show that the solution approaches the linear diffusion wave expressed in terms of the heat kernels as time tends to infinity. The proof is based on the detailed pointwise estimates of solutions in the Fourier space.
DIFFERENTIAL SUSCEPTIBILITY TIME-DEPENDENT SIR EPIDEMIC MODEL
Authors: ZHANG TAILEI , LIU JUNLI , TENG ZHIDONG
Published: April 2008

A non-autonomous epidemic dynamical system, in which we include variable susceptibility, is proposed. Some threshold conditions are derived which determine whether or not the disease will go to extinction. Some new threshold values, [Formula: see text], [Formula: see text] and [Formula: see text], are deduced for this general time-dependent system such that when [Formula: see text] is greater than 0, the disease is endemic in the sense of permanence and when one of the threshold values [Formula: see text] and [Formula: see text] is less than 0, the disease will die out. As an application of these results, the basic reproductive number ℛ0will be given if all the coefficients are periodic with common period. In addition, ℛ0< 1 implies the global stability of the disease-free periodic solution. Some corollaries are given for periodic and almost-periodic cases. The theoretical results are confirmed by a special example and numerical simulations.
ON THE PERMANENCE FOR n-SPECIES NON-AUTONOMOUS LOTKA–VOLTERRA COMPETITIVE SYSTEM WITH INFINITE DELAYS AND FEEDBACK CONTROLS
Authors: WANG KAI , TENG ZHIDONG , JIANG HAIJUN
Published: April 2008

In this paper, a class of n-species nonautonomous Lotka–Volterra competitive system with infinite delays and feedback controls is studied. A new criterion on the permanence of species is established. This result shows that the feedback controls do not influence the permanence of species.
EXISTENCE OF POSITIVE PERIODIC SOLUTIONS FOR NEUTRAL POPULATION MODEL WITH DELAYS
Authors: WANG QI , DAI BINXIANG
Published: April 2008

In this paper, by using the theory of abstract continuous theorem of k-set contractive operator and some analysis techniques, we obtain some sufficient conditions for the existence of positive periodic solutions for a neutral population model.
Biosynthesis of the Iron-Molybdenum Cofactor of Nitrogenase
Authors: Rubio Luis M. , Ludden Paul W.
Published: April 2008

The iron-molybdenum cofactor (FeMo-co), located at the active site of the molybdenum nitrogenase, is one of the most complex metal cofactors known to date. During the past several years, an intensive effort has been made to purify the proteins involved in FeMo-co synthesis and incorporation into nitrogenase. This effort is starting to provide insights into the structures of the FeMo-co biosynthetic intermediates and into the biochemical details of FeMo-co synthesis.
Stress and Microstructure in Electrodeposited Copper Nanofilms by Substrate Curvature and In-situ Electrochemical AFM Measurements
Authors: Ahmed S , Ahmed T. T. , O' Grady M. , Nakahara S. , Buckley D. N.
Published: April 2008

Both AFM imaging and stress measurements were carried out in-situ during potentiostatic electrodeposition of copper on gold in 0.05 mol dm-3 CuSO4 in 0.1 mol dm-3 H2SO4. In the absence of additives, compressive stress generally developed initially and films subsequently underwent a compressive-to-tensile (C-T) transition. The nucleation density measured by AFM increased from 2.7x107 cm-2 at -75 mV to 2.5x109 cm-2 at -300 mV. Very little coalescence of nuclei was observed at -75 mV but the rate of coalescence increased rapidly with increasing negative potential. The time for the C-T transition correspondingly decreased rapidly until, at -75 mV, none was observed. This is consistent with models that attribute the C-T transition to increasing tensile stress due to coalescence of nuclei. With a combination of Cl-, PEG and MPSA, compressive stress generally developed initially and was greater than in additive-free electrolyte. At less negative potentials, the stress continued to evolve in the compressive direction, even though the rate of coalescence of nuclei was rapid. At intermediate potentials (-90 mV to -150 mV), classical C-T-C behavior was observed; at more negative potentials the stress continued to evolve in the tensile direction. This enhancement of a compressive component of stress is attributed to incorporation of additive-derived impurities.
Relationships Between Morphology and Stress-State of Gold-Silver Alloys and Nanoporous Gold Blanket Films
Authors: Seker Erkin , Gaskins John , Begley Matthew R. , Bart-Smith Hilary , Zangari G. , Kelly Robert G. , Reed Michael L.
Published: April 2008

Gold-silver alloy films deposited on silicon wafers were annealed at temperatures between 100{degree sign}C and 400{degree sign}C, and subsequently dealloyed. The grain morphology and stress-state evolution of the samples before and after dealloying were studied by scanning electron microscopy and wafer curvature measurements. The residual stress in alloy films was augmented through thermal treatment; however, the subsequent dealloying step mitigated the residual stress without introducing significant changes in pore morphology. Possible mechanisms for stress and morphology evolution are reported.
Voltammogram of Dimethyl Analogue of Fuchsone: Simulation
Authors: Haque Inam U. , Khan Asim , Iqbal Shahid , Bano Kiran , Akram Wajiha
Published: April 2008

Electrochemical simulation of the cyclic voltammogram of a 2,6-di-methyl-4-(diphenylmethylene)-2,5-cyclohexadien-1-one in DMSO/tetra-n-butylammonium hexafluorophosphate at a mercury cathode was carried out using two shareware simulation programs; CVSIM and ESP 2.4. Two cathodic and two anodic peaks were analyzed.
A Study for Optimization of Lead Frame Precision in Spray Etching Process
Authors: Jeong HeungCheol , Choi GyungMin , Kim DuckJool
Published: April 2008

The objective of this study is to predict the etching characteristics for optimization on the lead frame process. Characteristics such as the etching factor and uniformity were investigated for different actual operating conditions; spray pressure, distance from the nozzle tip, pipe pitch, and nozzle pitch. The correlation between the etching and spray characteristics was analyzed to develop the etching model. Spray characteristics obtained from an experiment using a phase Doppler anemometer system were then simulated using a Monte-Carlo technique. The spray and etching characteristics were correlated with each other and simulated results agreed well with the measured data for a lead frame etching process. The optimal operating parameters under various conditions were successfully determined.
Electrochemical and Microstructure Characterization of (Ni0.5Co0.5)-MgO-TiO2-YSZ Cermet Anode
Authors: Weerapakkaroon Wichapun , Teoh Wah Tzu , Kazunori Sato
Published: April 2008

The Ni0.5Co0.5-MgO-TiO2-(8 mol%Y2O3-ZrO2) (NCMTO-YSZ) cermet anode showed a higher cell performance than NiO-YSZ and Ni0.5Co0.5O-YSZ cermet anodes under dry CH4 fuel, while the cell performance between Ni0.5Co0.5O-YSZ and NCMTO-YSZ cermet anodes were not significantly different under H2 fuel. NCMTO-YSZ decreased the anodic overvoltage and polarization resistance because Ni0.5Co0.5-MgO solid solution existing in the cermet anode contributes to increase active sites for the electrochemical oxidation of methane. The enhancement of the direct methane oxidation was caused by the microstructure improvement owing to MgO and a small amount of TiO2 solid solution.
Preparation and Characterisation of Self-Assembled Monolayers on Germanium Surfaces
Authors: Lommel Martin , Mankel Eric , Kolbesen Bernd
Published: April 2008

The formation of Self-Assembled Monolayers (SAMs) by specific organic molecules with appropriate anchor groups on semiconductor surfaces may be used to probe the chemical state and quality of the surface or to achieve surface passivation. Molecules with thiole anchor groups are capable to bond via a Ge-S bond to hydrogen-terminated germanium surfaces. We have prepared SAMs of alkylthioles with different head groups on germanium. Since the surface preparation of germanium is not well understood and developed the controlled preparation of an oxide-free completely H-terminated surface turned out as major challenge and prerequisite for SAMs formation of alkylthioles. Several approaches have been studied. The HF treatment provided the most promising results. Nevertheless the maximum coverage by SAMs achieved was 50 % depending on the preparation conditions. The characterization of the germanium surface prior to and after SAMs formation has been performed by AFM, XPS and TXRF.
A Study of Electrical Properties of SiGe Film with Various Oxidation Conditions
Authors: Chang Kow-Ming , Kuo Jiun-Ming , Wu Heng-Hsin , Tzeng Wen-Hsien , Wu Tzu-Li , Chen Bwo-Ning , Lin Jian-Hong
Published: April 2008

In this study, various oxidation conditions were performed of SiGe film, and a conventional p-type thin-film-transistor (TFT) was fabricated on it. I-V characteristics were measured to investigate the influence on electrical properties of the various oxidation conditions. It is found that the devices of higher oxidation temperature, longer oxidation time, and higher oxygen flow show better electrical performance. It is also found that devices under lower oxidation rate have lower leakage current and then induce higher On/Off ratio.
Influence of phosphagen concentration on phosphocreatine breakdown kinetics. Data from human gastrocnemius muscle
Authors: Francescato Maria Pia , Cettolo Valentina , di Prampero Pietro Enrico
Published: April 2008

At the onset of a square-wave exercise of moderate intensity, in the absence of any detectable lactate production, the hydrolysis of phosphocreatine (PCr) fills the gap between energy requirement and energy yield by oxidative pathways, thus representing a readily available source of energy for the muscle. We verified experimentally the relationships between high-energy phosphates and/or their changes and the time constant of PCr concentration ([PCr]) kinetics in humans (τPCr). High-energy phosphate concentration (by31P-NMR spectroscopy) in the calf muscles were measured during three repetitions of the rest-to-work transition of moderate aerobic square-wave exercise on nine healthy volunteers, while resting [PCr] was estimated from the appropriate spectroscopy data. PCr concentration decreased significantly (22 ± 6%) from rest to steady-state exercise, without differences among the three repetitions. Absolute resting [PCr] and τPCrwere consistent with literature values, amounting to 27.5 ± 2.2 mM and 23.9 ± 2.9 s, respectively. No significant relationships were detected between individual τPCrand mechanical power, fraction or absolute amount of PCr hydrolyzed, or change in ADP concentration. On the contrary, individual τPCr(s) was linearly related to absolute resting [PCr] (mM), the relationship being described by: τPCr= 0.656 + 0.841·[PCr] ( n = 9, R = 0.708, P < 0.05). These data support the view that in humans PCr concentration sets the time course of the oxidative metabolism in skeletal muscle at the start of exercise, being one of the main controllers of oxidative phosphorylation.
Pulmonary changes in a mouse model of combined burn and smoke inhalation-induced injury
Authors: Mizutani Akio , Enkhbaatar Perenlei , Esechie Aimalohi , Traber Lillian D. , Cox Robert A. , Hawkins Hal K. , Deyo Donald J. , Murakami Kazunori , Noguchi Takayuki , Traber Daniel L.
Published: April 2008

The morbidity and mortality of burn victims increase when burn injury is combined with smoke inhalation. The goal of the present study was to develop a murine model of burn and smoke inhalation injury to more precisely reveal the mechanistic aspects of these pathological changes. The burn injury mouse group received a 40% total body surface area third-degree burn alone, the smoke inhalation injury mouse group received two 30-s exposures of cotton smoke alone, and the combined burn and smoke inhalation injury mouse group received both the burn and the smoke inhalation injury. Animal survival was monitored for 120 h. Survival rates in the burn injury group, the smoke inhalation injury group, and the combined injury group were 70%, 60%, and 30%, respectively. Mice that received combined burn and smoke injury developed greater lung damage as evidenced by histological changes (septal thickening and interstitial edema) and higher lung water content. These mice also displayed more severely impaired pulmonary gas exchange [arterial Po2(PaO2)/inspired O2fraction (FiO2) < 200]. Lung myeloperoxidase activity was significantly higher in burn and smoke-injured animals compared with the other three experimental groups. Plasma NO2−/NO3−, lung inducible nitric oxide synthase (iNOS) activity, and iNOS mRNA increased with injury; however, the burn and smoke injury group exhibited a higher response. Severity of burn and smoke inhalation injury was associated with more pronounced production of nitric oxide and accumulation of activated leukocytes in lung tissue. The murine model of burn and smoke inhalation injury allows us to better understand pathophysiological mechanisms underlying cardiopulmonary morbidity secondary to burn and smoke inhalation injury.
Altered Synaptic Dynamics and Hippocampal Excitability but Normal Long-Term Plasticity in Mice Lacking Hyperpolarizing GABAA Receptor-Mediated Inhibition in CA1 Pyramidal Neurons
Authors: Riekki Ruusu , Pavlov Ivan , Tornberg Janne , Lauri Sari E. , Airaksinen Matti S. , Taira Tomi
Published: April 2008

GABAA receptor (GABA-AR)-mediated inhibition is critical for proper operation of neuronal networks. Synaptic inhibition either shifts the membrane potential farther away from the action potential firing threshold (hyperpolarizing inhibition) or via increase in the membrane conductance shunts the excitatory currents. However, the relative importance of these different forms of inhibition on the hippocampal function is unclear. To study the functional consequences of the absence of hyperpolarizing inhibition, we have used KCC2-deficient mice (KCC2hy/null) maintaining only 15–20% of the neuron-specific K-Cl-cotransporter. Gramicidin-perforated patch-clamp recordings in hippocampal CA1 pyramidal cells revealed that the reversal potential of the GABA-AR-mediated postsynaptic currents ( EGABA-A) was ∼20 mV more positive in KCC2hy/null mice than in wild-type (WT) animals. The basic glutamatergic transmission appeared unaltered in the KCC2hy/null mice, yet they displayed lowered threshold for stimulation-induced synchronous afterdischarges in the CA1 area. Also fatigue of field excitatory postsynaptic potentials/excitatory postsynaptic currents in response to repetitious stimulation was smaller in KCC2hy/null mice, indicating altered synaptic dynamics. Interestingly, this effect was present also under blockade of GABA-ARs and was dependent on the extracellular K+ concentration. Moreover, there were no differences in the levels of either long-term potentiation or long-term depression between the genotypes. The local hippocampal CA1 network can in several aspects maintain its functional viability even in the absence of hyperpolarizing inhibition in pyramidal cells. Our results underscore the central role of shunting type of inhibition in controlling the neuronal excitation/inhibition balance. Moreover, our data demonstrate a novel, unexpected role for the KCC2, namely the modulation of properties of glutamatergic transmission during repetitious afferent activity.
Upper Limb Asymmetries in the Matching of Proprioceptive Versus Visual Targets
Authors: Goble Daniel J. , Brown Susan H.
Published: April 2008

The purpose of the current study was to determine the extent to which “sensory dominance” exists in right-handers with respect to the utilization of proprioceptive versus visual feedback. Thirteen right-handed adults performed two target-matching tasks using instrumented manipulanda. In the proprioceptive matching task, the left or right elbow of blindfolded subjects was passively extended by a torque motor system to a target position and held for 3 s before being returned to the start position. The target angle was then matched with either the ipsilateral or contralateral arm. In the second task, visual matching, circular targets were briefly projected to either side of a visual fixation point located in front of the subject. Subjects then matched the target positions with a laser pointer by moving either the ipsilateral or contralateral arm. Overall, marked arm differences in accuracy were seen based on the type of sensory feedback used for target presentation. For the proprioceptive matching task errors were smaller for the nonpreferred left arm, whereas during the visual matching task smaller errors were found for the preferred right arm. These results suggest a left arm/right hemisphere advantage for proprioceptive feedback processing and a right arm/left hemisphere advantage for visual information processing. Such asymmetries may reflect fundamental differences between the two arm/hemisphere systems during the performance of bimanual tasks where the preferred arm requires visual guidance to manipulate an object, whereas the nonpreferred stabilizes that object on the basis of proprioceptive feedback.
Evaluation of Adapted Whole-Blood Interferon-γ Release Assays for the Diagnosis of Pleural Tuberculosis
Authors: Chegou Novel N. , Walzl Gerhard , Bolliger Chris T. , Diacon Andreas H. , van den Heuvel Michel M.
Published: April 2008

Background: Pleural tuberculosis (TB) remains difficult to diagnose despite numerous diagnostic tools. Recently, in vitro interferon (IFN)-γ-based assays have been introduced in the diagnosis of latent TB, but these techniques have not been established in the diagnosis of active TB disease, including pleural TB. Objectives: It was the aim of this study to assess the accuracy of the commercially available QuantiFERON® TB Gold assay and adapted variants of the assay, using pleural fluid or isolated pleural fluid cells for the diagnosis of pleural TB. Methods: We recruited 66 consecutive patients with a pleural effusion of unknown cause presenting at a tertiary academic health care centre in Cape Town, South Africa, a high prevalence area of TB. Blood and pleural fluid were collected at presentation for IFN-γ assays and the results evaluated for diagnostic accuracy. Results: The clinical diagnosis was TB in 30 (46%), malignancy in 20 (30%), parapneumonic effusion/empyema in 8 (12%) and effusion due to other causes in 8 patients (12%). Ex vivo pleural fluid IFN-γ levels accurately identified TB in all patients and were superior to the QuantiFERON In Tube assay using blood and pleural fluid (73 and 57% sensitivity, with 71 and 87% specificity, respectively) and the QuantiFERON Gold assay applied to isolated pleural fluid cells (100% sensitivity and 67% specificity). Conclusion: The ex vivo pleural fluid interferon-γ level is an accurate marker for the diagnosis of pleural TB, and the QuantiFERON TB Gold assay performed with peripheral blood or adapted for pleural fluid cells does not add diagnostic value.
TRIB3 R84 Variant Is Associated With Impaired Insulin-Mediated Nitric Oxide Production in Human Endothelial Cells
Authors: Andreozzi Francesco , Formoso Gloria , Prudente Sabrina , Hribal Marta Letizia , Pandolfi Assunta , Bellacchio Emanuele , Di Silvestre Sara , Trischitta Vincenzo , Consoli Agostino , Sesti Giorgio
Published: April 2008

Background—

In the endothelium, insulin promotes nitric oxide (NO) production, through the insulin receptor/IRS-1/PI3-Kinase/Akt/eNOS signaling pathway. An inhibitor of insulin action, TRIB3, has recently been identified which affects insulin action by binding to and inhibiting Akt phosphorylation. We have recently described a Q84R gain-of-function polymorphism of
TRIB3
with the R84 variant being associated with insulin resistance and an earlier age at myocardial infarction.

Methods and Results—

To investigate the
TRIB3
R84 variant impact on endothelial insulin action, we cultured human umbilical vein endothelial cells (HUVECs) naturally carrying different
TRIB3
genotypes (QQ-, QR-, or RR-HUVECs). TRIB3 inhibitory activity on insulin-stimulated Akt phosphorylation and the amount of protein which was coimmunoprecipitable with Akt were significantly greater in QR- and RR- as compared to QQ- HUVECs. After insulin stimulation, Akt and eNOS activation as well as NO production were markedly decreased in QR- and RR- as compared to QQ-HUVECs. TRIB3 molecular modeling analysis provided insights into the structural changes related to the polymorphisms potentially determining differences in protein-protein interaction with Akt.

Conclusions—

Our data demonstrate that the
TRIB3
R84 variant impairs insulin signaling and NO production in human endothelial cells. This finding provides a plausible biological background for the deleterious role of
TRIB3
R84 on genetic susceptibility to coronary artery disease.
Mutations in Bone Morphogenetic Protein Type II Receptor Cause Dysregulation of Id Gene Expression in Pulmonary Artery Smooth Muscle Cells
Authors: Yang Jun , Davies Rachel J. , Southwood Mark , Long Lu , Yang Xudong , Sobolewski Anastasia , Upton Paul D. , Trembath Richard C. , Morrell Nicholas W.
Published: April 2008

Heterozygous germ line mutations in the gene encoding the bone morphogenetic protein (BMP) type II receptor occur in more than 80% of patients with familial pulmonary arterial hypertension. Because inhibitors of DNA binding (Id) genes are major targets of BMP/Smad signaling, we studied the regulation of these transcription factors in pulmonary artery smooth muscle cells harboring mutations in BMP type II receptor and control cells. Mutant cells demonstrated a marked deficiency in BMP4-stimulated Id1 and Id2 gene and protein expression compared with control cells. Mutant cells were deficient in Smad1/5 signaling in response to BMPs but also in extracellular signal-regulated kinase (ERK)1/2 activation. We provide evidence for an important interaction between Smad1/5 and ERK1/2 signaling in the regulation of Id gene expression. Thus, BMP4-induced Id1 expression was negatively regulated by ERK1/2 activation. The mechanism involves ERK1/2-dependent phosphorylation of the Smad1 linker region (serine 206), which limits C-terminal serine 463/465 phosphorylation and inhibits Smad nuclear accumulation. Furthermore, activation of ERK1/2 by platelet-derived growth factor BB also caused Smad1 linker region phosphorylation and inhibited BMP4-induced Id1 gene expression. In contrast, Id2 expression was positively regulated by ERK1/2. Moreover, we show that both BMP type II receptor mutation and Id1 knockdown leads to loss of growth suppression by BMPs. Taken together, these findings indicate an important interaction between ERK1/2 and Smad1/5 in the regulation of Id genes. Platelet-derived growth factor, via ERK1/2, further impairs the deficiency in Smad signaling found in BMP type II receptor mutant cells. The integration of these signals at the level of Id gene expression may contribute to the pathogenesis of familial pulmonary arterial hypertension.
Cardioprotective and Vasodilatory Actions of Glucagon-Like Peptide 1 Receptor Are Mediated Through Both Glucagon-Like Peptide 1 Receptor–Dependent and –Independent Pathways
Authors: Ban Kiwon , Noyan-Ashraf M. Hossein , Hoefer Judith , Bolz Steffen-Sebastian , Drucker Daniel J. , Husain Mansoor
Published: April 2008

Background—

The glucagon-like peptide 1 receptor (GLP-1R) is believed to mediate glucoregulatory and cardiovascular effects of the incretin hormone GLP-1(7-36) (GLP-1), which is rapidly degraded by dipeptidyl peptidase-4 (DPP-4) to GLP-1(9-36), a truncated metabolite generally thought to be inactive. Novel drugs for the treatment of diabetes include analogues of GLP-1 and inhibitors of DPP-4; however, the cardiovascular effects of distinct GLP-1 peptides have received limited attention.

Methods and Results—

Here, we show that endothelium and cardiac and vascular myocytes express a functional GLP-1R as GLP-1 administration increased glucose uptake, cAMP and cGMP release, left ventricular developed pressure, and coronary flow in isolated mouse hearts. GLP-1 also increased functional recovery and cardiomyocyte viability after ischemia-reperfusion injury of isolated hearts and dilated preconstricted arteries from wild-type mice. Unexpectedly, many of these actions of GLP-1 were preserved in Glp1r
−/−
mice. Furthermore, GLP-1(9-36) administration during reperfusion reduced ischemic damage after ischemia-reperfusion and increased cGMP release, vasodilatation, and coronary flow in wild-type and Glp1r
−/−
mice, with modest effects on glucose uptake. Studies using a DPP-4–resistant GLP-1R agonist and inhibitors of DPP-4 and nitric oxide synthase showed that the effects of GLP-1(7-36) were partly mediated by GLP-1(9-36) through a nitric oxide synthase–requiring mechanism that is independent of the known GLP-1R.

Conclusions—

These data describe cardioprotective actions of GLP-1(7-36) mediated through the known GLP-1R and novel cardiac and vascular actions of GLP-1(7-36) and its metabolite GLP-1(9-36) independent of the known GLP-1R. Our data suggest that the extent to which GLP-1 is metabolized to GLP-1(9-36) may have functional implications in the cardiovascular system.
Mineralocorticoid Receptor Blockade Reverses Obesity-Related Changes in Expression of Adiponectin, Peroxisome Proliferator-Activated Receptor-γ, and Proinflammatory Adipokines
Authors: Guo Christine , Ricchiuti Vincent , Lian Bill Q. , Yao Tham M. , Coutinho Patricia , Romero José R. , Li Jianmin , Williams Gordon H. , Adler Gail K.
Published: April 2008

Background—

In obesity, decreases in adiponectin and increases in proinflammatory adipokines are associated with heart disease. Because adipocytes express mineralocorticoid receptor (MR) and MR blockade reduces cardiovascular inflammation and injury, we tested the hypothesis that MR blockade reduces inflammation and expression of proinflammatory cytokines in adipose tissue and increases adiponectin expression in adipose tissue and hearts of obese mice.

Methods and Results—

We determined the effect of MR blockade (eplerenone, 100 mg/kg per day for 16 weeks) on gene expression in retroperitoneal adipose and heart tissue from obese, diabetic
db
/
db
mice (n=8) compared with untreated obese, diabetic
db
/
db
mice (n=10) and lean, nondiabetic
db
/+ littermates (n=11). Expression of tumor necrosis factor-α, monocyte chemoattractant protein-1, plasminogen activator inhibitor type 1, and macrophage protein CD68 increased, and expression of adiponectin and peroxisome proliferator-activated receptor-γ decreased in retroperitoneal adipose tissue from obese versus lean mice. In addition, adiponectin expression in heart was reduced in obese versus lean mice. MR blockade prevented these obesity-related changes in gene expression. Furthermore, treatment of undifferentiated preadipocytes with aldosterone (10
−8
mol/L for 24 hours) increased mRNA levels of tumor necrosis factor-α and monocyte chemoattractant protein-1 and reduced mRNA and protein levels of peroxisome proliferator-activated receptor-γ and adiponectin, supporting a direct aldosterone effect on gene expression.

Conclusions—

MR blockade reduced expression of proinflammatory and prothrombotic factors in adipose tissue and increased expression of adiponectin in heart and adipose tissue of obese, diabetic mice. These effects on adiponectin and adipokine gene expression may represent a novel mechanism for the cardioprotective effects of MR blockade.
Impact of Time of Presentation on the Care and Outcomes of Acute Myocardial Infarction
Authors: Jneid Hani , Fonarow Gregg C. , Cannon Christopher P. , Palacios Igor F. , Kilic Teoman , Moukarbel George V. , Maree Andrew O. , LaBresh Kenneth A. , Liang Li , Newby L. Kristin , Fletcher Gerald , Wexler Laura , Peterson Eric
Published: April 2008

Background—

Prior studies have demonstrated an inconsistent association between patients’ arrival time for acute myocardial infarction (AMI) and their subsequent medical care and outcomes.

Methods and Results—

Using a contemporary national clinical registry, we examined differences in medical care and in-hospital mortality among AMI patients admitted during regular hours (weekdays 7
am
to 7
pm
) versus off-hours (weekends, holidays, and 7
pm
to 7
am
weeknights). The study cohort included 62 814 AMI patients from the Get With the Guidelines–Coronary Artery Disease database admitted to 379 hospitals throughout the United States from July 2000 through September 2005. Overall, 33 982 (54.1%) patients arrived during off-hours. Compared with those arriving during regular hours, eligible off-hour patients were slightly less likely to receive primary percutaneous coronary intervention (adjusted odds ratio [OR], 0.93; 95% confidence interval [CI], 0.89 to 0.98), had longer door-to-balloon times (median, 110 versus 85 minutes;
P
<0.0001), and were less likely to achieve door-to-balloon ≤90 minutes (adjusted OR, 0.34; 95% CI, 0.29 to 0.39). Arrival during off-hours was associated with slightly lower overall revascularization rates (adjusted OR, 0.94; 95% CI, 0.90 to 0.97). No measurable differences, however, were found in in-hospital mortality between regular hours and off-hours in the overall AMI, ST-elevated MI, and non–ST-elevated MI cohorts (adjusted OR, 0.99; 95% CI, 0.93 to 1.06; adjusted OR, 1.05; 95% CI, 0.94 to 1.18; and adjusted OR, 0.97; 95% CI, 0.90 to 1.04, respectively). Similar observations were made across most age and sex subgroups and with an alternative definition for arrival time (weekends/holidays versus weekdays).

Conclusions—

Despite slightly fewer primary percutaneous coronary interventions and overall revascularizations and significantly longer door-to-balloon times, patients presenting with AMI during off-hours had in-hospital mortality similar to those presenting during regular hours.
Thymosin β4 Is an Essential Paracrine Factor of Embryonic Endothelial Progenitor Cell–Mediated Cardioprotection
Authors: Hinkel Rabea , El-Aouni Chiraz , Olson Tonia , Horstkotte Jan , Mayer Stefan , Müller; Sebastian , Willhauck Michael , Spitzweg Christine , Gildehaus Franz-Josef , Münzing Wolfgang , Hannappel Ewald , Bock-Marquette Ildiko , DiMaio J. Michael , Hatzopoulos Antonis K. , Boekstegers Peter , Kupatt Christian
Published: April 2008

Background—

Prolonged myocardial ischemia results in cardiomyocyte loss despite successful revascularization. We have reported that retrograde application of embryonic endothelial progenitor cells (eEPCs) provides rapid paracrine protection against ischemia-reperfusion injury. Here, we investigated the role of thymosin β4 (Tβ4) as a mediator of eEPC-mediated cardioprotection.

Methods and Results—

In vitro, neonatal rat cardiomyocytes were subjected to hypoxia-reoxygenation in the absence or presence of eEPCs with or without Tβ4 short hairpin RNA (shRNA) transfection. In vivo, pigs (n=9 per group) underwent percutaneous left anterior descending artery occlusion for 60 minutes on day 1. After 55 minutes of ischemia, control eEPCs (5×10
6
cells) or cells transfected with Tβ4 shRNA when indicated or 15 mg Tβ4 alone were retroinfused into the anterior interventricular vein. Segmental endocardial shortening in the infarct zone at 150-bpm atrial pacing, infarct size (triphenyl tetrazolium chloride viability and methylene blue exclusion), and inflammatory cell influx (myeloperoxidase activity) were determined 24 hours later. Survival of neonatal rat cardiomyocytes increased from 32±4% to 90±2% after eEPC application, an effect sensitive to shRNA transfection compared with Tβ4 (45±7%). In vivo, infarct size decreased with eEPC application (38±4% versus 54±4% of area at risk;
P
<0.01), an effect abolished by Tβ4 shRNA (62±3%). Segmental subendocardial shortening improved after eEPC treatment (22±3% versus −3±4% of control area) unless Tβ4 shRNA was transfected (−6±4%). Retroinfusion of Tβ4 mimicked eEPC application (infarct size, 37±3%; segmental endocardial shortening, 34±7%). Myeloperoxidase activity (3323±388 U/mg in controls) was decreased by eEPCs (1996±546 U/mg) or Tβ4 alone (1455±197 U/mg) but not Tβ4 shRNA–treated eEPCs (5449±829 U/mg).

Conclusion—

Our findings show that short-term cardioprotection derived by regional application of eEPCs can be attributed, at least in part, to Tβ4.