bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of stand age and spatial location on throughfall chemistry beneath black spruce
Authors: Carleton T. J. , Kavanagh Trudy
Published: April 2008

Total summer precipitation and throughfall chemistry are investigated beneath black spruce (Piceamariana (Mill.) B.S.P.) in central Canada under the null hypothesis that no variation occurs with postfire stand age nor from one location on the feather moss dominated forest floor to another. Data from collectors at inner, mid, and edge radial positions beneath individual tree crowns and between neighbouring trees (gaps), within each of a 61-, 90-, and 120-year-old stand, were summed to yield a growing season total volume and the deposition of NO3−-N, NH4+-N, PO43−-P, K+, Ca2+, and Mg2+. Relative to incident precipitation, NO3−-N and NH4+-N showed highly significant net uptake by the canopy foliage. In contrast, K+, Ca2+, and Mg2+ showed net losses from the canopy throughfall. No appreciable difference in net throughfall (i.e., throughfall minus precipitation) volume and K+ deposition appeared among the stands. However, NH4+-N, NO3−-N, PO43−-P, Ca2+, and Mg2+ showed significant differences. NH4+-N and NO3−-N were less readily retained by foliage of the old stand than by that of the young stand, whereas Ca2+ and Mg2+ leached more readily from trees in the 120-year-old stand than in the other two. PO43−-P showed no net throughfall in the 61- and 120-year-old stands, whereas there were net losses from the canopy of the 90-year-old stand. This may reflect soil differences between the 90-year-old site and the other two. Significant differences in spatial location emerged for all variables measured. Net throughfall deposition of PO43−-P, K+, Ca2+, and Mg2+ declined from the inner to gap positions, whereas volume, NO3−-N, and NH4+-N increased. These effects were proportional to the canopy profile depth above each collector. The heterogeneity observed in nutrient deposition on the forest floor has important implications for the distribution and growth of forest floor plants, such as mosses and lichens, which seem to depend on precipitation and throughfall for their nutrient supply.
GLOBALLY DYNAMICAL BEHAVIORS FOR DISCRETE LASOTA–WAZEWSKA MODEL WITH SEVERAL DELAYS AND ALMOST PERIODIC COEFFICIENTS
Authors: WANG XIAO , LI ZHIXIANG
Published: April 2008

The present paper gives two methods to obtain the existence and uniqueness of almost periodic solution [Formula: see text] of the following discrete Lasota–Wazewska model [Formula: see text] one is a new fixed point theorem in cone proved by us, the other is contraction mapping principle. In addition, some sufficient conditions are established for global attractivity of [Formula: see text] by constructing Lyapunov functional.
STABILITY OF T-PERIODIC SOLUTION ON THE EXTENDED SIMPLIFIED BRUSSELATOR MODEL
Authors: LIAN JIN-GUO , ZHANG HONG-KUN
Published: April 2008

Brusselator model is a very typical autocatalytic reaction diffusion system. The bifurcation of steady-states of Brusselator model can be used to explain spot patterns of certain animals such as leopard and jaguar. Periodic patterns can be found throughout whole natural world, so it is very interesting to study patterns generated by the bifurcation of periodic solutions in extended Brusselator (EB) model, which extends Brusselator to T-periodic coefficients. In this paper, we study extended simplified Brusselator (ESB) model, which is EB model without diffusion terms. We find a unique T-periodic solution x0(t) in the strictly positively invariant region [Formula: see text] and prove its stability. This result establishes a foundation to study the bifurcation of EB model from x0(t). We also develop techniques of using degree theory and Floquet theory to analyze existence, uniqueness and stability of a periodic solution.
A COMPARISON INVESTIGATION OF THE SIMPLEST MODELS OF CIRCADIAN RHYTHMS
Authors: TANG SANYI
Published: April 2008

We present three different simplest realistic models of the circadian pacemaker that can be interpreted in molecular terms: Goodwin model, piece-wise Goodwin model and delay model. The main purpose is to investigate how the common parameters in these three model affect the dynamical behavior. In particular, the existence and stability of periodic solutions of three models are studied, and the parameter space where the steady state becomes unstable is given which can be used to compare the effect of parameters on the oscillations of three models. Furthermore, the effects of parameters on the period of periodic solutions and phase response curves are investigated and discussed. Our results confirm that all three models can be used to simulate the realistic circadian rhythms. However, in practice, which model is chosen depends on the real data.
Psychophysical Evaluation for Visual Prosthesis
Authors: Dagnelie Gislin
Published: April 2008

Vision restoration through retinal, optic nerve, and cortical implants is no longer just the stuff of fantasy. The design and development of visual prostheses rapidly move from the engineering phase toward preclinical and clinical trials, yet the benchmarks to determine their efficacy in blind research subjects have received very little attention, and likewise the selection criteria and preparation of early recipients of these devices. This article examines the aspects of vision for which prostheses may be of help, the selection of early prosthesis wearers, and the pre- and postimplant evaluations required to assess safety and efficacy. I concentrate on the functional assessment, and particularly on psychophysical methodology, but also address other measures of safety and efficacy, as well as approaches to vision rehabilitation with visual prostheses. Finally, I speculate what roles the first few generations of visual prostheses may play, and emphasize the importance of using simulations to support the development and rehabilitation process.
Global Spread and Persistence of Dengue
Authors: Kyle Jennifer L. , Harris Eva
Published: April 2008

Dengue is a spectrum of disease caused by four serotypes of the most prevalent arthropod-borne virus affecting humans today, and its incidence has increased dramatically in the past 50 years. Due in part to population growth and uncontrolled urbanization in tropical and subtropical countries, breeding sites for the mosquitoes that transmit dengue virus have proliferated, and successful vector control has proven problematic. Dengue viruses have evolved rapidly as they have spread worldwide, and genotypes associated with increased virulence have expanded from South and Southeast Asia into the Pacific and the Americas. This review explores the human, mosquito, and viral factors that contribute to the global spread and persistence of dengue, as well as the interaction between the three spheres, in the context of ecological and climate changes. What is known, as well as gaps in knowledge, is emphasized in light of future prospects for control and prevention of this pandemic disease.
Nicotinic Acid, Nicotinamide, and Nicotinamide Riboside: A Molecular Evaluation of NAD+ Precursor Vitamins in Human Nutrition
Authors: Bogan Katrina L , Brenner Charles
Published: April 2008

Although baseline requirements for nicotinamide adenine dinucleotide (NAD+) synthesis can be met either with dietary tryptophan or with less than 20 mg of daily niacin, which consists of nicotinic acid and/or nicotinamide, there is growing evidence that substantially greater rates of NAD+ synthesis may be beneficial to protect against neurological degeneration, Candida glabrata infection, and possibly to enhance reverse cholesterol transport. The distinct and tissue-specific biosynthetic and/or ligand activities of tryptophan, nicotinic acid, nicotinamide, and the newly identified NAD+ precursor, nicotinamide riboside, reviewed herein, are responsible for vitamin-specific effects and side effects. Because current data suggest that nicotinamide riboside may be the only vitamin precursor that supports neuronal NAD+ synthesis, we present prospects for human nicotinamide riboside supplementation and propose areas for future research.
In-Situ Monitoring of the Internal Stress Evolution during Thin Film Anodising
Authors: Proost Joris , Vanhumbeeck Jean-François , Van Overmeere Quentin
Published: April 2008

Transitions in the internal stress evolution have systematically been observed during both galvanostatic and potentiostatic staircase anodising of Ti thin films. They have been attributed to, respectively, oxygen evolution and mechanical breakdown. A simple scaling model is presented to rationalize the effect of oxygen evolution on the internal stress by taking into account the effective growth efficiency.
Regularities of Electrolytic Dissociation of Methyl Derivatives of Saturated Dicarboxylic Acids
Authors: Kvaratskhelia Elene , Kvaratskhelia Ramaz
Published: April 2008

With the aid of the suggested by authors method the values of the degrees of dissociation of the methyl derivatives of malonic, succinic and glutaric acids in the concentration range 0.0001-0.01M and the pH range 1-4 were calculated. The equations for calculation of the concentrations of various ionized and non-ionized forms of studied acids were also suggested.
Electrochemical Studies of the Fries Rearrangement in Ionic Liquids
Authors: Cheek Graham T.
Published: April 2008

The Fries rearrangement of phenyl benzoate has been investigated in the aluminum chloride : 1-ethyl-3-methylimidazolium chloride (EMIC) system using both weakly acidic and neutral buffered melt compositions. The rearrangement products at 70o - 90oC were 2-hydroxybenzophenone (2-OHBP) and 4-hydroxybenzophenone (4-OHBP) in both systems. This reaction was also attempted in the ionic liquid EMIBF4, adding BF3 etherate as the Lewis acid. At a BF3 : PB 3 : 1 ratio, conversion to the PB : BF3 complex was not complete, but reaction at 85oC gave small amounts of 2-OHBP and 4-OHBP. Addition of AlCl3 to PB in EMIBF4 gave a more complete complexation of PB than did BF3 etherate.
Functional meta-analysis of double connectivity in gene coexpression networks in mammals
Authors: Gustin Marie-Paule , Paultre Christian Z. , Randon Jacques , Bricca Giampiero , Cerutti Catherine
Published: April 2008

In functional genomics, the high-throughput methods such as microarrays 1) allow analysis of the relationships between genes considering them as elements of a network and 2) lead to biological interpretations thanks to Gene Ontology. But up to now it has not been possible to find relationships between the functions and the connectivity of the genes in coexpression networks. To achieve this aim, we have defined a double connectivity for each gene by the numbers of its significant negative and positive correlations with the other genes within a given biological condition, or group. Here, based on the analysis of 1,260 DNA microarrays, we show that this double connectivity clearly separates two types of genes, those with a predominantly strong negative connectivity, hub− genes, and those with a predominantly strong positive connectivity, hub+ genes. Interestingly, the hub+ genes concerned transcription factors more often than by chance and, similarly, for the hub− genes concerning miRNA predicted targets. Furthermore, a meta-analysis of GO annotations carried out on 67 groups in humans and rats shows that these two types of genes correspond to a functional biological duality. The hub− genes were mainly involved in basic functions common to all eukaryote cells, whereas the hub+ genes were mainly involved in specialized functions related to cell differentiation and communication. The separation and the biological role of these hub− and hub+ genes provide a powerful new tool for a better understanding of the control and regulation of the key genes involved in cellular differentiation and physiopathological conditions.
Alternative splicing and exon duplication generates 10 unique porcine 5-HT4 receptor splice variants including a functional homofusion variant
Authors: De Maeyer Joris H. , Aerssens Jeroen , Verhasselt Peter , Lefebvre Romain A.
Published: April 2008

5-HT4 receptors are present in human and porcine atrial myocytes while they are absent from the hearts of small laboratory animals. The pig is therefore the only available nonprimate animal model in which to study cardiac 5-HT4 receptor function under physiological conditions. While several human splice variants of the 5-HT4 receptor have been described, the splicing behavior of this receptor in porcine tissue is currently unknown. Here we report on the identification of nine novel COOH-terminal splice variants of the porcine 5-HT4 receptor, which were named 5-HT4(b2, j, k, l, m, o, p, q, r). The internal h-variant was found in combination with several COOH-terminal exons. In addition, splice variants were found that comprised duplicated exons fused to the common region of the 5-HT4 receptor, thereby providing evidence for a duplication of the porcine HTR4 gene. One of these variants putatively encoded a nine transmembrane-spanning domain homofusion receptor, 5-HT4(9TM); also the other variants with a duplicated region might translate into functional, transcriptionally fused dimeric 5-HT4 receptor variants. The elucidation of the genomic context confirmed that the variants were not genomic artefacts but originated from alternative splicing. This was further corroborated by a functional analysis of the variants 5-HT4(a), 5-HT4(r), and 5-HT4(9TM). To our knowledge, our data are the first to report on a functional GPCR with more than seven predicted transmembrane domains. These findings urge for caution when interpreting data on 5-HT4 receptor-related pharmacology obtained in the pig; validation at the molecular level might be needed before extrapolating results to human.
Stromal Cell–Derived Factor-1α Is Cardioprotective After Myocardial Infarction
Authors: Saxena Ankur , Fish Jason E. , White Michael D. , Yu Sangho , Smyth James W.P. , Shaw Robin M. , DiMaio J. Michael , Srivastava Deepak
Published: April 2008

Background—

Heart disease is a leading cause of mortality throughout the world. Tissue damage from vascular occlusive events results in the replacement of contractile myocardium by nonfunctional scar tissue. The potential of new technologies to regenerate damaged myocardium is significant, although cell-based therapies must overcome several technical barriers. One possible cell-independent alternative is the direct administration of small proteins to damaged myocardium.

Methods and Results—

Here we show that the secreted signaling protein stromal cell–derived factor-1α (SDF-1α), which activates the cell-survival factor protein kinase B (PKB/Akt) via the G protein–coupled receptor CXCR4, protected tissue after an acute ischemic event in mice and activated Akt within endothelial cells and myocytes of the heart. Significantly better cardiac function than in control mice was evident as early as 24 hours after infarction as well as at 3, 14, and 28 days after infarction. Prolonged survival of hypoxic myocardium was followed by an increase in levels of vascular endothelial growth factor protein and neoangiogenesis. Consistent with improved cardiac function, mice exposed to SDF-1α demonstrated significantly decreased scar formation than control mice.

Conclusion—

These findings suggest that SDF-1α may serve a tissue-protective and regenerative role for solid organs suffering a hypoxic insult.
Risk Factors for Aborted Cardiac Arrest and Sudden Cardiac Death in Children With the Congenital Long-QT Syndrome
Authors: Goldenberg Ilan , Moss Arthur J. , Peterson Derick R. , McNitt Scott , Zareba Wojciech , Andrews Mark L. , Robinson Jennifer L. , Locati Emanuela H. , Ackerman Michael J. , Benhorin Jesaia , Kaufman Elizabeth S. , Napolitano Carlo , Priori Silvia G. , Qi Ming , Schwartz Peter J. , Towbin Jeffrey A. , Vincent G. Michael , Zhang Li
Published: April 2008

Background—The congenital long-QT syndrome (LQTS) is an important cause of sudden cardiac death in children without structural heart disease. However, specific risk factors for life-threatening cardiac events in children with this genetic disorder have not been identified.

Methods and Results—Cox proportional-hazards regression modeling was used to identify risk factors for aborted cardiac arrest or sudden cardiac death in 3015 LQTS children from the International LQTS Registry who were followed up from 1 through 12 years of age. The cumulative probability of the combined end point was significantly higher in boys (5%) than in girls (1%;P<0.001). Risk factors for cardiac arrest or sudden cardiac death during childhood included corrected QT interval [QTc] duration >500 ms (hazard ratio [HR]; 2.72; 95% confidence interval [CI], 1.50 to 4.92;P=0.001) and prior syncope (recent syncope [<2 years]: HR, 6.16; 95% CI 3.41 to 11.15;P<0.001; remote syncope [≥2 years]: HR, 2.67; 95% CI, 1.22 to 5.85;P=0.01) in boys, whereas prior syncope was the only significant risk factor among girls (recent syncope: HR, 27.82; 95% CI, 9.72 to 79.60;P<0.001; remote syncope: HR, 12.04; 95% CI, 3.79 to 38.26;P<0.001). β-Blocker therapy was associated with a significant 53% reduction in the risk of cardiac arrest or sudden cardiac death (P=0.01).

Conclusions—LQTS boys experience a significantly higher rate of fatal or near-fatal cardiac events than girls during childhood. A QTc duration >500 ms and a history of prior syncope identify risk in boys, whereas prior syncope is the only significant risk factor among girls. β-Blocker therapy is associated with a significant reduction in the risk of life-threatening cardiac events during childhood.
Changes in Insulin Resistance and Cardiovascular Risk During Adolescence
Authors: Moran Antoinette , Jacobs David R. , Steinberger Julia , Steffen Lyn M. , Pankow James S. , Hong Ching-Ping , Sinaiko Alan R.
Published: April 2008

Background—

Developmental changes in insulin resistance and cardiovascular risk were studied in youths 11 to 19 years of age.

Methods and Results—

A cohort was randomly selected after blood pressure screening of Minneapolis, Minn, school children. Studies were done 3 times on this cohort and once on their siblings (996 observations on 507 individuals from 363 families). Insulin sensitivity was determined by euglycemic clamp. Body mass index and waist circumference increased similarly in both sexes from ages 11 to 19 years. Body fat decreased in males and increased in females (
P
<0.001). Lean body mass increased at a steeper rate in males (
P
<0.0001). Insulin resistance was lower in males at 11 years but increased steadily to 19 years (
P
=0.003); in contrast, it did not increase in females. Thus, despite being less insulin resistant at 11 years and decreasing in fatness during puberty, males became more insulin resistant than females by 19 years of age. Triglycerides increased in males and high-density lipoprotein cholesterol decreased, whereas the opposite pattern was seen in females, which resulted in higher triglycerides and lower high-density lipoprotein cholesterol in males at 19 years. No gender difference in low-density lipoprotein or total cholesterol was seen. Systolic blood pressure increased in both sexes but at a greater rate in boys (
P
=0.03).

Conclusions—

During the transition from late childhood through adolescence, insulin resistance in males increased in association with increased triglycerides and decreased high-density lipoprotein cholesterol, despite a concurrent reduction in body fatness, whereas the opposite occurred in females. These gender-related developmental changes in insulin resistance, which were independent from changes in fatness, total cholesterol, and low-density lipoprotein cholesterol, are consistent with an early role for insulin resistance in the increased cardiovascular risk found in males.
Cardiac Allograft Vasculopathy
Authors: Schmauss Daniel , Weis Michael
Published: April 2008

Cardiac allograft vasculopathy (CAV) continues to limit the long-term success of cardiac transplantation. Recent insights have underscored the fact that innate and adaptive immune responses are involved in the pathogenesis of CAV. Vascular lesions are the result of cumulative endothelial injuries induced both by alloimmune responses and by nonspecific insults (including ischemia-reperfusion injury, viral infections, and metabolic disorders) in the context of impaired repair mechanisms. Intravascular ultrasound is the most sensitive method for detection of CAV, and progressive intimal thickening in the first posttransplant year identifies patients at high risk for future cardiovascular events. Encouraging results with regard to the detection of CAV by noninvasive methods should be an incentive to apply routine noninvasive imaging during mid- to long-term follow-up. Improved immunosuppressive drugs, including mycophenolate mofetil and proliferation signal inhibitors, as well as statins (in part via immunomodulation), have beneficial effects on CAV progression, although there is still a need to confirm the impact of vasodilators in improving outcome after heart transplantation. Coronary revascularization for CAV is only palliative, with no long-term survival benefit. Three main strategies for CAV prevention are currently under investigation: inhibition of growth factors and cytokines, cell therapy, and tolerance induction. However, because individual responses to an allograft change over time, assays to monitor the recipient’s immune response and individualized methods for therapeutic immune modulation are clearly needed.
Long-QT Syndrome After Age 40
Authors: Goldenberg Ilan , Moss Arthur J. , Bradley James , Polonsky Slava , Peterson Derick R. , McNitt Scott , Zareba Wojciech , Andrews Mark L. , Robinson Jennifer L. , Ackerman Michael J. , Benhorin Jesaia , Kaufman Elizabeth S. , Locati Emanuela H. , Napolitano Carlo , Priori Silvia G. , Qi Ming , Schwartz Peter J. , Towbin Jeffrey A. , Vincent G. Michael , Zhang Li
Published: April 2008

Background—

Previous studies that assessed the risk of life-threatening cardiac events in patients with congenital long-QT syndrome (LQTS) have focused mainly on the first 4 decades of life, whereas the clinical course of this inherited cardiac disorder in the older population has not been studied.

Methods and Results—

The risk of aborted cardiac arrest or death from age 41 though 75 years was assessed in 2759 subjects from the International LQTS Registry, categorized into electrocardiographically affected (corrected QT interval [QTc] ≥470 ms), borderline (QTc 440 to 469 ms), and unaffected (QTc <440 ms) subgroups. The affected versus unaffected adjusted hazard ratio for aborted cardiac arrest or death was 2.65 (
P
<0.001) in the age range of 41 to 60 years and 1.23 (
P
=0.31) in the age range of 61 to 75 years. The clinical course of study subjects displayed gender differences: Affected LQTS women experienced a significantly higher cumulative event rate (26%) than borderline (16%) and unaffected (12%) women (
P
=0.001), whereas event rates were similar among the 3 respective subgroups of men (29%, 26%, and 27%;
P
=0.16). Recent syncope (<2 years in the past) was the predominant risk factor in affected subjects (hazard ratio 9.92,
P
<0.001), and the LQT3 genotype was identified as the most powerful predictor of outcome in a subset of 871 study subjects who were genetically tested for a known LQTS mutation (hazard ratio 4.76,
P
=0.02).

Conclusions—

LQTS subjects maintain a high risk for life-threatening cardiac events after age 40 years. The phenotypic expression of affected subjects is influenced by age-specific factors related to gender, clinical history, and the LQTS genotype.
Angiotensin-Converting Enzyme Inhibition Improves Vascular Function in Rheumatoid Arthritis
Authors: Flammer Andreas J. , Sudano Isabella , Hermann Frank , Gay Steffen , Forster Adrian , Neidhart Michel , Künzler Peter , Enseleit Frank , Périat Daniel , Hermann Matthias , Nussberger Juerg , Luscher Thomas F. , Corti Roberto , Noll Georg , Ruschitzka Frank
Published: April 2008

Background—

The excess in cardiovascular risk in patients with rheumatoid arthritis provides a strong rationale for early therapeutical interventions. In view of the similarities between atherosclerosis and rheumatoid arthritis and the proven benefit of angiotensin-converting enzyme inhibitors in atherosclerotic vascular disease, it was the aim of the present study to delineate the impact of ramipril on endothelial function as well as on markers of inflammation and oxidative stress in patients with rheumatoid arthritis.

Methods and Results—

Eleven patients with rheumatoid arthritis were included in this randomized, double-blind, crossover study to receive ramipril in an uptitration design (2.5 to 10 mg) for 8 weeks followed by placebo, or vice versa, on top of standard antiinflammatory therapy. Endothelial function assessed by flow-mediated dilation of the brachial artery, markers of inflammation and oxidative stress, and disease activity were investigated at baseline and after each treatment period. Endothelial function assessed by flow-mediated dilation increased from 2.85±1.49% to 4.00±1.81% (
P
=0.017) after 8 weeks of therapy with ramipril but did not change with placebo (from 2.85±1.49% to 2.84±2.47%;
P
=0.88). Although systolic blood pressure and heart rate remained unaltered, diastolic blood pressure decreased slightly from 78±7 to 74±6 mm Hg (
P
=0.03). Tumor necrosis factor-α showed a significant inverse correlation with flow-mediated dilation (
r
=−0.408,
P
=0.02), and CD40 significantly decreased after ramipril therapy (
P
=0.049).

Conclusions—

Angiotensin-converting enzyme inhibition with 10 mg/d ramipril for 8 weeks on top of current antiinflammatory treatment markedly improved endothelial function in patients with rheumatoid arthritis. This finding suggests that angiotensin-converting enzyme inhibition may provide a novel strategy to prevent cardiovascular events in these patients.
Effect of Short Call Admission on Length of Stay and Quality of Care for Acute Decompensated Heart Failure
Authors: Schuberth Jennifer L. , Elasy Tom A. , Butler Javed , Greevy Robert , Speroff Theodore , Dittus Robert S. , Roumie Christianne L.
Published: April 2008

Background—

In response to residency work hour restrictions, programs restructured call schedules, increasing the use of short call (daytime admitting teams). Few data exist on the effect of short call on quality of patient care. Our objective was to examine the effect of short call admission on length of stay and quality of care for patients with acute decompensated heart failure.

Methods and Results—

We conducted a retrospective cohort study of 218 patients admitted with acute decompensated heart failure to the Nashville VA Medical Center between July 1, 2003, and June 30, 2005. The primary exposure was short call, and the primary outcome was length of stay. The secondary outcomes—diuretic dosing, weight monitoring, and hospital complications—were determined through a combination of administrative data and chart review. Patients admitted to short call had a longer median length of stay than patients admitted to long call (5.2 days [25% to 75%, 3.2 to 8 days] versus 3.9 days [interquartile range, 2.7 to 6.5 days];
P
=0.0004). After adjustment for covariates, short call had a 44% increase in length of stay (95% CI, 15 to 80) compared with long call. Short call patients received fewer diuretic doses in the first 24 hours of hospitalization (1.80 versus 2.12;
P
=0.014) and had a longer median time to the second dose of loop diuretics compared with long call patients (17.9 hours versus 16.2 hours;
P
=0.044).

Conclusions—

Admission to short call is predictive of increased length of stay, a decreased number of diuretic doses, and delays in the timing of diuretics among patients with acute decompensated heart failure. Additional studies are needed to clarify the impact of short call admission on inpatient quality of care.
Depressive Symptoms and the Risk of Atherosclerotic Progression Among Patients With Coronary Artery Bypass Grafts
Authors: Wellenius Gregory A. , Mukamal Kenneth J. , Kulshreshtha Ambar , Asonganyi Sharon , Mittleman Murray A.
Published: April 2008

Background—

Depressive symptoms have been associated with increased risk of coronary artery disease and poor prognosis among patients with existing coronary artery disease, but whether depressive symptoms specifically influence atherosclerotic progression among such patients is uncertain.

Methods and Results—

The Post-CABG Trial randomized patients with a history of coronary bypass graft surgery to either an aggressive or a moderate lipid-lowering strategy and to either warfarin or placebo. Coronary angiography was conducted at enrollment and after a median follow-up of 4.2 years. Depressive symptoms were assessed at enrollment with the Centers for Epidemiologic Studies Depression scale (CES-D) in 1319 patients with 2496 grafts. In models that adjusted for age, gender, race, treatment assignment, and years since coronary bypass graft surgery, a CES-D score ≥16 was positively associated with risk of substantial graft disease progression (OR 1.50, 95% CI 1.08 to 2.10,
P
=0.02) and marginally associated with a 0.11-mm (95% CI −0.22 to 0.01 mm,
P
=0.07) decrease in minimum lumen diameter, but not with risk of graft occlusion (
P
=0.30). Additional adjustment for past medical history, blood pressure, and renal function did not materially alter these results. This association was virtually absent among participants randomly assigned to aggressive lipid-lowering therapy.

Conclusions—

These findings suggest that depressive symptoms are associated with a higher risk of atherosclerotic progression among patients with saphenous vein grafts and that aggressive lipid lowering can minimize this increased risk. Whether depressive symptoms increase progression in other types of coronary atherosclerosis and whether aggressive lipid lowering attenuates such progression will require additional study.
Noncanonical Wnt11 Signaling Is Sufficient to Induce Cardiomyogenic Differentiation in Unfractionated Bone Marrow Mononuclear Cells
Authors: Flaherty Michael P. , Abdel-Latif Ahmed , Li Qianhong , Hunt Greg , Ranjan Smita , Ou Qinghu , Tang Xian-Liang , Johnson Robin K. , Bolli Roberto , Dawn Buddhadeb
Published: April 2008

Background—

Despite the frequent clinical use of adult unfractionated bone marrow mononuclear cells (BMMNCs) for cardiac repair, whether these cells are capable of undergoing cardiomyogenic differentiation in vitro remains uncertain. In addition, the role of Wnt signaling in cardiomyogenic differentiation of adult cells is unclear.

Methods and Results—

Unfractionated BMMNCs were isolated from adult mice via Ficoll-Paque density-gradient centrifugation and cultured in the presence of Wnt3a or Wnt11. In control BMMNCs, Wnt11 was not expressed, whereas the expression of markers of pluripotency (Oct-4 and Nanog), as well as that of Wnt3a and β-catenin, decreased progressively during culture. Exposure to Wnt3a rescued β-catenin expression and markedly increased the expression of Oct-4 and Nanog, concomitant with increased cell proliferation and CD45 expression. In contrast, exposure to ectopically expressed noncanonical Wnt11 markedly decreased the expression of Oct-4 and Nanog and induced mRNA expression (quantitative real-time reverse-transcription polymerase chain reaction) of cardiac-specific genes (Nkx2.5, GATA-4, atrial natriuretic peptide, α- and β-myosin heavy chain, and cardiac troponin T) by day 3 with subsequent progression to a pattern characteristic of the cardiac fetal gene program. After 21 days, 27.6±0.6% and 29.6±1.4% of BMMNCs expressed the cardiac-specific antigens cardiac myosin heavy chain and cardiac troponin T, respectively (immunocytochemistry), indicating cardiomyogenic lineage commitment. Wnt11-induced cardiac-specific expression was completely abolished by the protein kinase C inhibitor bisindolylmaleimide I, partially abolished by the c-Jun-N-terminal kinase inhibitor SP600125, and attenuated by the Wnt inhibitor Dickkopf-1.

Conclusions—

In adult density-gradient separated BMMNCs, canonical Wnt3a promotes stemness, proliferation, and hematopoietic commitment, whereas noncanonical signaling via Wnt11 induces robust cardiomyogenic differentiation in a protein kinase C– and c-Jun-N-terminal kinase–dependent manner.
Therapeutic Uses of Inorganic Nitrite and Nitrate
Authors: Butler Anthony R. , Feelisch Martin
Published: April 2008

Potential carcinogenic effects, blue baby syndrome, and occasional intoxications caused by nitrite, as well as the suspected health risks related to fertilizer overuse, contributed to the negative image that inorganic nitrite and nitrate have had for decades. Recent experimental studies related to the molecular interaction between nitrite and heme proteins in blood and tissues, the potential role of nitrite in hypoxic vasodilatation, and an unexpected protective action of nitrite against ischemia/reperfusion injury, however, paint a different picture and have led to a renewed interest in the physiological and pharmacological properties of nitrite and nitrate. The range of effects reported suggests that these simple oxyanions of nitrogen have a much richer profile of biological actions than hitherto assumed, and several efforts are currently underway to investigate possible beneficial effects in the clinical arena. We provide here a brief historical account of the medical uses of nitrite and nitrate over the centuries that may serve as a basis for a careful reassessment of the health implications of their exposure and intake and may inform investigations into their therapeutic potential in the future.
Excessive Nitric Oxide Function and Blood Pressure Regulation in Patients With Autonomic Failure
Authors: Gamboa Alfredo , Shibao Cyndya , Diedrich André , Paranjape Sachin Y. , Farley Ginnie , Christman Brian , Raj Satish R. , Robertson David , Biaggioni Italo
Published: April 2008

Approximately 50% of patients with autonomic failure (AF) suffer from supine hypertension, even those with very low plasma norepinephrine and renin. Because NO is arguably the most potent metabolic modulator of blood pressure, we hypothesized that impaired NO function contributes to supine hypertension in AF. However, we found that AF patients (n=14) were more sensitive to the pressor effects of the NO synthase inhibitor
N
G
-monomethyl-
l
-arginine, suggesting increased NO function rather than deficiency; a lower dose of
N
G
-monomethyl-
l
-arginine was needed to produce a similar increase in blood pressure in AF patients, as in healthy control subjects in whom AF was induced with the ganglionic blocker trimethaphan (171±37 mg versus 512±81 mg, respectively;
P
=0.001). Furthermore, potentiation of the actions of endogenous NO with the phosphodiesterase inhibitor sildenafil (25 mg PO) decreased nighttime supine systolic blood pressure from 182±11 to 138±4 mm Hg in 8 AF patients with supine hypertension (
P
=0.012 compared with placebo). Finally, AF patients tolerated a greater degree of upright tilt during infusion of
N
G
-monomethyl-
l
-arginine (56±6° versus 41±4° with placebo; n=7;
P
=0.014), an improvement in orthostatic tolerance similar to that obtained with equipressor doses of phenylephrine. In conclusion, AF patients do not have NO deficiency contributing to supine hypertension. Instead, they have increased NO function contributing to their orthostatic hypotension. Potentiation of NO could be used in the treatment of supine hypertension, and its inhibition offers a novel approach to improve orthostatic hypotension.
Central Pressure: Variability and Impact of Cardiovascular Risk Factors
Authors: McEniery Carmel M. , Yasmin  , McDonnell Barry , Munnery Margaret , Wallace Sharon M. , Rowe Chloe V. , Cockcroft John R. , Wilkinson Ian B.
Published: April 2008

Pulse pressure varies throughout the arterial tree, resulting in a gradient between central and peripheral pressure. Factors such as age, heart rate, and height influence this gradient. However, the relative impact of cardiovascular risk factors and atheromatous disease on central pressure and the normal variation in central pressure in healthy individuals are unclear. Seated peripheral (brachial) and central (aortic) blood pressures were assessed, and the ratio between aortic and brachial pulse pressure (pulse pressure ratio, ie, 1/amplification) was calculated in healthy individuals, diabetic subjects, patients with cardiovascular disease, and in individuals with only 1 of the following: hypertension, hypercholesterolemia, or smoking. The age range was 18 to 101 years, and data from 10 613 individuals were analyzed. Compared with healthy individuals, pulse pressure ratio was significantly increased (ie, central systolic pressure was relatively higher) in individuals with risk factors or disease (
P
<0.01 for all of the comparisons). Although aging was associated with an increased pulse pressure ratio, there was still an average±SD difference between brachial and aortic systolic pressure of 11±4 and 8±3 mm Hg for men and women aged >80 years, respectively. Finally, stratifying individuals by brachial pressure revealed considerable overlap in aortic pressure, such that >70% of individuals with high-normal brachial pressure had similar aortic pressures as those with stage 1 hypertension. These data demonstrate that cardiovascular risk factors affect the pulse pressure ratio, and that central pressure cannot be reliably inferred from peripheral pressure. However, assessment of central pressure may improve the identification and management of patients with elevated cardiovascular risk.
Valsartan Improves Arterial Stiffness in Type 2 Diabetes Independently of Blood Pressure Lowering
Authors: Karalliedde Janaka , Smith Andrew , DeAngelis Lorenita , Mirenda Vincenzo , Kandra Albert , Botha Jaco , Ferber Philippe , Viberti Giancarlo
Published: April 2008

Increased arterial stiffness, as estimated from aortic pulse wave velocity (Ao-PWV), and albuminuria are independent predictors for cardiovascular disease in type 2 diabetes mellitus (T2DM). Whether angiotensin receptor blockers (ARBs), drugs with cardio-renal protective effects, improve Ao-PWV to a greater extent than other equipotent antihypertensive medications remains unclear. After a 4-week washout phase, we compared the effects of valsartan (n=66), an ARB, with that of amlodipine (n=65), a calcium channel blocker on Ao-PWV in 131 T2DM patients with pulse pressure (PP) ≥60 mm Hg and raised albumin excretion rate (AER) in a 24-week randomized, double-blind, parallel group study. Hydrochlorothiazide (HCTZ) 25 mg/d was added to valsartan 160 mg and amlodipine 5 mg/od uptitrated to 10 mg/od after 4 weeks to ensure equivalent BP control. After 24 weeks brachial and central aortic PP had fallen to a similar extent with attained mean (SD) brachial and central PP of 61.6 (13.6) and 47.3 (14.1) mm Hg in the valsartan/HCTZ group and 61.5 (12.2) and 47.3 (9.9) mm Hg in the amlodipine group, respectively. Ao-PWV showed a significantly greater reduction, mean (95% CI), −0.9 m/s (−1.4 to −0.3) for valsartan/HCTZ compared to amlodipine (
P
=0.002). AER fell significantly only with Val/HCTZ from 30.8(20.4, 46.5) to 18.2(12.5, 26.3) mcg/min, (
P
=0.01) with between treatment difference in favor of Val/HCTZ of −15.3mcg/min (
P
<0.001). Changes in AER and Ao-PWV were not correlated. Valsartan/HCTZ improves arterial stiffness and AER to a significantly greater extent than amlodipine despite similar central and brachial BP control. These 2 effects, which appear independent of each other, may explain the specific cardio-renal protective properties of ARBs.
Postconflict Reconstruction in Africa: Flawed Ideas about Failed States
Authors: Englebert Pierre , Tull Denis M.
Published: April 2008

Postconflict state reconstruction has become a priority of donors in Africa. Yet, externally sponsored reconstruction efforts have met with limited achievements in the region. This is partly due to three flawed assumptions on which reconstruction efforts are predicated. The first is that Western state institutions can be transferred to Africa. The poor record of past external efforts to construct and reshape African political and economic institutions casts doubts on the overly ambitious objectives of failed state reconstruction. The second flawed assumption is the mistaken belief in a shared understanding by donors and African leaders of failure and reconstruction. Donors typically misread the nature of African politics. For local elites, reconstruction is the continuation of war and competition for resources by new means. Thus their strategies are often inimical to the building of strong public institutions. The third flawed assumption is that donors are capable of rebuilding African states. Their ambitious goals are inconsistent with their financial, military, and symbolic means. Yet, African societies are capable of recovery, as Somaliland and Uganda illustrate. Encouraging indigenous state formation efforts and constructive bargaining between social forces and governments might prove a more fruitful approach for donors to the problem of Africa's failed states.
Partitioning to Peace: Sovereignty, Demography, and Ethnic Civil Wars
Authors: Johnson Carter
Published: April 2008

Some scholars have proposed partition as a way to solve ethnic civil wars. Partition theorists advocate the demographic separation of ethnic groups into different states, arguing that this is the best chance for an enduring peace. Opponents argue that partition is costly in terms of its human toll and that its advocates have yet to demonstrate its effectiveness beyond a limited number of self-selected case studies. This analysis systematically examines the outcome of partition, highlighting the centrality of demography by introducing an index that measures the degree to which a partition separates ethnic groups. This index is applied to all civil wars ending in partition from 1945 to 2004. Partitions that completely separated the warring groups did not experience a recurrence of war and low-level violence for at least five years, outperforming both partitions that did not separate ethnic groups and other ethnic war outcomes. These results challenge other studies that examine partition as a war outcome. The results also have direct implications for Iraq's civil war, postindependence Kosovo, and other ethnic civil wars.
What Terrorists Really Want: Terrorist Motives and Counterterrorism Strategy
Authors: Abrahms Max
Published: April 2008

What do terrorists want? No question is more fundamental for devising an effective counterterrorism strategy. The international community cannot expect to make terrorism unprofitable and thus scarce without knowing the incentive structure of its practitioners. The strategic model—the dominant paradigm in terrorism studies—posits that terrorists are political utility maximizers. According to this view, individuals resort to terrorism when the expected political gains minus the expected costs outweigh the net expected benefits of alternative forms of protest. The strategic model has widespread currency in the policy community; extant counterterrorism strategies seek to defeat terrorism by reducing its political utility. The most common strategies are to fight terrorism by decreasing its political benefits via a strict no concessions policy; decreasing its prospective political benefits via appeasement; or decreasing its political benefits relative to nonviolence via democracy promotion. Despite its policy relevance, the strategic model has not been tested. This is the first study to comprehensively assess its empirical validity. The actual record of terrorist behavior does not conform to the strategic model's premise that terrorists are rational actors primarily motivated to achieving political ends. The preponderance of empirical and theoretical evidence is that terrorists are rational people who use terrorism primarily to develop strong affective ties with fellow terrorists. Major revisions in both the dominant paradigm in terrorism studies and the policy community's basic approach to fighting terrorism are consequently in order.
Dinámica de estereotipos de género y poder: un estudio transcultural
Authors: López-Zafra Esther , García-Retamero Rocío , Diekman Amanda , Eagly Alice H.
Published: April 2008

Las características que se atribuyen a hombres y mujeres influyen hasta el punto de determinar qué es correcto o no hacer, y también pueden influir en la participación y en la asunción de distintos roles sociales que impliquen poder. Tradicionalmente, los hombres han ocupado puestos de poder público mientras que las mujeres se han centrado en el ámbito privado.

En este estudio transcultural pretendemos comprobar si el que mujeres y hombres ocupen roles que se asociaban con el otro género, influye en la percepción sobre los estereotipos de género y sobre el poder, y si esto se produce de manera diferente en función de las transformaciones sociales del contexto en que se encuentran. Para ello 720 personas de España, Alemania y Estados Unidos de América participan en un experiment.

Entre nuestros resultados encontramos que se percibe que las mujeres han ganado, y seguirán haciéndolo en lo sucesivo, más poder público, y que también tienen más características masculinas. Este resultado es mayor en España que en Alemania y EEUU, por lo que encontramos un efecto importante del context.
Elección de carrera, desarrollo profesional y estereotipos de género
Authors: Barberá Ester , Candela Carlos , Ramos Amparo
Published: April 2008

El objetivo central de este estudio empírico es analizar la correspondencia entre la percepción que tienen los/as estudiantes sobre las carreras de Psicología e Ingeniería Industrial, por un lado, y los perfiles laborales demandados para estas dos profesiones, por otro. El criterio de partida es que existe un desajuste, de manera que las percepciones estudiantiles asocian la profesión de Psicología con rasgos estereotipados femeninos, mientras que la Ingeniería se sigue vinculando con rasgos estereotipados masculinos. Sin embargo, los perfiles requeridos para estas dos profesiones se caracterizan, en el momento actual, por compartir múltiples habilidades, destrezas y competencias, y por estar poco sesgados según criterios estereotipados de género. Han participado un total de 759 estudiantes valencianos de ESO y Bachiller, así como de Psicología e Ingeniería Industrial. Por su parte, la muestra de profesionales suma un total de 648 personas que ejercen su actividad como psicólogos/as o ingenieros/as industriales. Los resultados corroboran el desequilibrio entre la percepción estudiantil y la realidad laboral actual. Se discuten finalmente posibles propuestas educativas para modificar las percepciones y expectativas profesionales antes de la elección de carrera.
Estudio y análisis sobre cómo perciben el mobbing los trabajadores
Authors: Escartín Jordi , Rodríguez-Carballeira Álvaro , Porrúa Clara , Martín-Peña Javier
Published: April 2008

Este trabajo se plantea como primer objetivo analizar la forma en que los trabajadores definen y delimitan el abuso psicológico en el lugar de trabajo. Y en segundo lugar analizar la incidencia del mobbing en dicha muestra de trabajadores. A través de un cuestionario auto-administrado elaborado por los autores para esta investigación, se pidió a los participantes (trabajadores en activo) a través de una pregunta abierta que expresaran qué entienden por mobbing. Además, se les pidió que juzgaran el grado de proximidad o experiencia con dicho fenómeno. Los trabajadores participantes en el estudio han descrito el mobbing apelando a los factores psicológicos y psicosociales, en detrimento de los aspectos físicos y sexuales. Además, la incidencia hallada del 10% se aprecia muy similar a la encontrada por diversos estudios de diferentes países europeos. Esta investigación ha profundizado en las percepciones de los trabajadores acerca de lo que entienden por mobbing, procurando contribuir de este modo a una mejor delimitación y evaluación del abuso psicológico en el lugar de trabajo.