bluuebunny/crossref_metadata_2025 huggingface dataset:
Air pollution and inflammation in type 2 diabetes: a mechanism for susceptibility
Authors: O’Neill M S , Veves A , Sarnat J A , Zanobetti A , Gold D R , Economides P A , Horton E S , Schwartz J
Published: December 2006

Background:Particulate air pollution has been associated with several adverse cardiovascular health outcomes, and people with diabetes may be especially vulnerable. One potential pathway is inflammation and endothelial dysfunction—processes in which cell adhesion molecules and inflammatory markers play important roles.

Aim:To examine whether plasma levels of soluble intercellular adhesion molecule 1 (ICAM-1), vascular cell adhesion molecule 1 (VCAM-1) and von Willebrand factor (vWF) were associated with particle exposure in 92 Boston area residents with type 2 diabetes.

Methods:Daily average ambient levels of air pollution (fine particles (PM2.5), black carbon (BC) and sulphates) were measured approximately 500 m from the patient examination site and evaluated for associations with ICAM-1, VCAM-1 and vWF. Linear regressions were fit to plasma levels of ICAM-1, VCAM-1 and vWF, with the particulate pollutant index, apparent temperature, season, age, race, sex, glycosylated haemoglobin, cholesterol, smoking history and body mass index as predictors.

Results:Air pollutant exposure measures showed consistently positive point estimates of association with the inflammatory markers. Among participants not taking statins and those with a history of smoking, associations between PM2.5, BC and VCAM-1 were particularly strong.

Conclusions:These results corroborate evidence suggesting that inflammatory mechanisms may explain the increased risk of air pollution-associated cardiovascular events among those with diabetes.
PERFORMANCE ANALYSIS OF CREDIT-BASED FLOW CONTROL IN INFINIBAND INTERCONNECTION NETWORKS
Authors: Yan Shihang , Min Geyong , Awan Irfan
Published: December 2006

Credit-based flow control scheme that can be used to support both end-to-end and link-level flow control is becoming increasingly popular in high speed system area networks (SAN), e.g. InfiniBand networks where multiple processor nodes and I/O devices are interconnected using switched point-to-point links. By virtue of such a scheme, the downstream node sends credits to the upstream node indicating the availability of buffer spaces. Upon receiving credits, the upstream node injects packets into the networks. Performance analysis of credit-based flow control scheme plays an important role for the design and optimization of InfiniBand interconnection networks which have been widely used in many high-performance cluster, Grid and P2P computing systems. This study develops a new queueing network model for performance evaluation of credit-based flow control in InfiniBand networks. The performance metrics to be derived include the mean queue length, throughput and response time of the system. Simulation experiments have been used to validate the accuracy of the queueing network model. Results obtained from the analytical model have showed that this model can effectively evaluate the performance of credit-based flow control in InfiniBand networks.
GROWTH IN TOPOLOGICAL COMPLEXITY AND VOLUME GROWTH FOR RANDOM DYNAMICAL SYSTEMS
Authors: ZHU YUJUN
Published: December 2006

In this paper, relations between topological entropy, volume growth and the growth in topological complexity from homotopical and homological point of view are discussed for random dynamical systems. It is shown that, under certain conditions, the volume growth, the growth in fundamental group and the growth in homological group are all bounded from above by the topological entropy.
GENERALIZED FRACTIONAL LÉVY PROCESSES: A WHITE NOISE APPROACH
Authors: HUANG ZHI YUAN , LI PEI YAN
Published: December 2006

In this paper, with a simple condition on Lévy measure, we construct the (tempered) generalized fractional Lévy processes (GFLP) as Lévy white noise functionals and investigate their distribution and sample properties through this white noise approach. We also give some sufficient conditions under which the usual fractional Lévy processes (FLP) are well defined.
EXPONENTIAL INEQUALITIES AND FUNCTIONAL ESTIMATIONS FOR WEAK DEPENDENT DATA: APPLICATIONS TO DYNAMICAL SYSTEMS
Authors: MAUME-DESCHAMPS V.
Published: December 2006

We estimate density and regression functions for weak dependent data. Using an exponential inequality obtained by Dedecker and Prieur (New dependence coefficients. Examples and applications to statistics, Th. Rel. Fields132 (2005)) and by the author (Exponential inequalities and estimation of conditional probabilities, in Lect. Notes in Stat., Vol. 187 (Springer, 2006)), we control the deviation between the estimator and the function itself. These results are applied to a large class of dynamical systems and lead to estimations of invariant densities and on the mapping itself.
A multi-element study on metallophytes from mineralized areas in Botswana using ICP-AES and ICP-MS
Authors: Nkoane Bonang B. M. , Wibetoe Grethe , Lund Walter , Torto Nelson
Published: January 2007

A multi-element study was performed for metal-tolerant plants and the associated soils collected from four mineralized areas in Botswana using ICP-AES and ICP-MS. The elements were determined in the roots, stems and leaves of the three metallophytes,
Blepharis aspera
,
Blepharis diversispina
and
Helichrysum candolleanum
, previously known to accumulate Cu and Ni. The limits of detection (LOD) obtained for ICP-AES were in the ppm range while those for ICP-MS were down to sub-ppb level, allowing determination of elements in a wide concentration range.

Of the 62 elements studied, the following were found in higher concentrations than normal for plants: Al, Co, Cr, Cu, Fe and Ni in
B. aspera
; Al, Fe and Ti in
B. diversispina
; and Al, Ba, Cd, Cr, Cu, Fe, Ti and V in
H. candolleanum
. The rare earth elements (REEs) were also found in concentrations above normal for all plants: about one order of magnitude higher for the light REEs and two to three orders of magnitude for the heavy REEs. When the total contents of metals present in higher than normal amounts in the leaves were calculated, the concentrations were
c.
0.3% for
B. aspera
, 0.1–0.2% for
B. diversispina
and 0.4–1% for
H. candolleanum
. When the macronutrient metals (Ca, Mg, Mn, K, Na, Si and Zn) were included, the leaf total metal burden was in the range 6–9% for
B. diversispina
and
c.
3% for both
H. candolleanum
and
B. aspera
which grew side by side. The three plants showed different metal distribution patterns and levels. The elements that were found in the plants in amounts higher than normal also had elevated concentrations in the host soil.
Natural versus anthropogenic dispersion of metals to the environment in the Wulik River area, western Brooks Range, northern Alaska
Authors: Kelley Karen D. , Hudson Travis
Published: January 2007

Zinc–lead–silver mineral deposits in the Wulik River region, Alaska, contain an enormous accumulation of Zn. In addition to the giant deposits at Red Dog, at least nine other deposits are known. Natural weathering of these deposits has dispersed metals over a wide region over a long period of time (
c.
10 000 years) through transport by stream and groundwater, stream sediments, formation of soils, and perhaps wind-blown atmospheric deposition from weathering of naturally enriched Pb–Zn surface deposits. Anthropogenic input also contributes metals to the environment. Mining of the Red Dog deposit, which began in 1989, produces fine-grained galena and sphalerite concentrates that are transported from the mine site by truck to a storage port facility. Wind-blown dispersion of concentrate dust along the road and around the port facility has been a source of local metal-rich surficial materials.

Geochemical and mineralogical characteristics provide a means of distinguishing the natural versus anthropogenic metal sources. Soils over deposits have patterns of increasing metal contents with depth and proximity to the metal-bearing source, whereas ore concentrate dust is localized at the surface. The acidity produced by weathering of the sulphide deposits creates an environment in which elements such as Se and Mo are stable whereas Ca is not. Consequently, high Mo (up to 29 ppm) and Se (up to 17 ppm) and low Ca (<0.4%) concentrations characterize surficial materials near natural deposits. Acidic conditions also yield high Pb–Zn ratios (up to 70) because sphalerite is preferentially dissolved and Zn is mobilized during chemical weathering. In natural materials, secondary jarosite and anglesite are developed, and minor galena is etched and rounded due to a history of chemical and mechanical weathering. In contrast, dust-bearing samples have Pb/Zn ratios that are 0.4 or less, Ca contents are higher (0.2 to 3.6%), and Mo (<10 ppm) and Se (not detected) concentrations are low. Furthermore, galena and sphalerite grains are angular and secondary minerals are lacking.
Low-temperature serpentinization processes and kimberlite groundwater signatures in the Kirkland Lake and Lake Timiskiming kimberlite fields, Ontario, Canada: implications for diamond exploration
Authors: Sader Jamil A. , Leybourne Matthew I. , McClenaghan M. Beth , Hamilton Stewart M.
Published: January 2007

Groundwaters from diamondiferous kimberlite pipes in the Kirkland Lake and Lake Timiskaming regions display unusual geochemical characteristics and signatures compared with groundwaters from the surrounding host rock. Reaction modelling was used to better constrain water/rock ratios, alteration mineralogy and groundwater geochemistry. A soil-zone Ca-HCO
3
−
water from glacial till was reacted, using a reaction-modelling program, with three different suites of minerals: a kimberlite suite, a felsic intrusive suite and a mafic intrusive suite. Decreasing pH and alkalinity with increasing water/rock ratios in model reactions with the kimberlite suite suggest that sampled groundwaters are from both the hypabyssal facies (high pH and alkalinity; low water/rock ratios) and the diatreme facies (low pH and alkalinity; high water/rock ratios). Geochemical concentrations of sampled groundwaters from kimberlites were compared to modelled waters; results indicate that these waters are different from those flowing through local felsic or mafic intrusive rocks. The kimberlitic groundwaters, and modelled waters, contain low concentrations of Mg and Fe, high concentrations of K and Ca, have elevated pH (up to 12.45), and are defined as a Ca-OH
−
water for the A4 and B30 kimberlites. In contrast, the C14, Diamond Lake and 95-2 kimberlites contain groundwaters that have higher Mg and Fe, lower Ca and K concentrations, and relatively low pH (8.5–10). The reaction model suggests that different minerals precipitate where the water interacts with different kimberlite facies and/or where a different water/rock ratio exists. More hydroxide phases form where pH and hydroxide alkalinity are high. Where kimberlite waters interact with host-rock waters, minerals not likely to be found otherwise, such as magnesite, brucite and magnetite, may be detected along fractures, or near seeps or springs where groundwater comes to surface. Exploration for kimberlites can benefit from the use of groundwater. Groundwater interaction with kimberlitic rocks produces characteristic aqueous geochemical anomalies due to low-temperature serpentinization reactions. The identification of geochemical anomalies in the groundwaters down-flow of a kimberlite and the unusual mineral assemblages that may precipitate from these groundwaters may aid in the location of undiscovered kimberlites.
Pyruvate induces mitochondrial biogenesis by a PGC-1 α-independent mechanism
Authors: Wilson Leanne , Yang Qing , Szustakowski Joseph D. , Gullicksen P. Scott , Halse Reza
Published: December 2006

Oxidative cells increase mitochondrial mass in response to stimuli such as changes in energy demand or cellular differentiation. This plasticity enables the cell to adapt dynamically to achieve the necessary oxidative capacity. However, the pathways involved in triggering mitochondrial biogenesis are poorly defined. The present study examines the impact of altering energy provision on mitochondrial biogenesis in muscle cells. C2C12 myoblasts were chronically treated with supraphysiological levels of sodium pyruvate for 72 h. Treated cells exhibited increased mitochondrial protein expression, basal respiratory rate, and maximal oxidative capacity. The increase in mitochondrial biogenesis was independent of increases in peroxisomal proliferator activator receptor-γ coactivator-1α (PGC-1α) and PGC-1β mRNA expression. To further assess whether PGC-1α expression was necessary for pyruvate action, cells were infected with adenovirus containing shRNA for PGC-1α before treatment with pyruvate. Despite a 70% reduction in PGC-1α mRNA, the effect of pyruvate was preserved. Furthermore, pyruvate induced mitochondrial biogenesis in primary myoblasts from PGC-1α null mice. These data suggest that regulation of mitochondrial biogenesis by pyruvate in myoblasts is independent of PGC-1α, suggesting the existence of a novel energy-sensing pathway regulating oxidative capacity.
WNK4 kinase is a negative regulator of K+-Cl−cotransporters
Authors: Garzón-Muvdi Tomas , Pacheco-Alvarez Diana , Gagnon Kenneth B. E. , Vázquez Norma , Ponce-Coria José , Moreno Erika , Delpire Eric , Gamba Gerardo
Published: December 2006

WNK kinases [with no lysine (K) kinase] are emerging as regulators of several membrane transport proteins in which WNKs act as molecular switches that coordinate the activity of several players. Members of the cation-coupled chloride cotransporters family (solute carrier family number 12) are one of the main targets. WNK3 activates the Na+-driven cotransporters NCC, NKCC1, and NKCC2 and inhibits the K+-driven cotransporters KCC1 to KCC4. WNK4 inhibits the activity of NCC and NKCC1, while in the presence of the STE20-related proline-alanine-rich kinase SPAK activates NKCC1. Nothing is known, however, regarding the effect of WNK4 on the K+-Cl−cotransporters. Using the heterologous expression system of Xenopus laevis oocytes, here we show that WNK4 inhibits the activity of the K+-Cl−cotransporters KCC1, KCC3, and KCC4 under cell swelling, a condition in which these cotransporters are maximally active. The effect of WNK4 requires its catalytic activity because it was lost by the substitution of aspartate 318 for alanine (WNK4-D318A) that renders WNK4 catalytically inactive. In contrast, three different WNK4 missense mutations that cause pseudohypoaldosteronism type II do not affect the WNK4-induced inhibition of KCC4. Finally, we observed that catalytically inactive WNK4-D318A is able to bypass the tonicity requirements for KCC2 and KCC3 activation in isotonic conditions. This effect is enhanced by the presence of catalytically inactive SPAK, was prevented by the presence of protein phosphatase inhibitors, and was not present in KCC1 and KCC4. Our results reveal that WNK4 regulates the activity of the K+-Cl−cotransporters expressed in the kidney.
Lack of pendrin HCO3−transport elevates vestibular endolymphatic [Ca2+] by inhibition of acid-sensitive TRPV5 and TRPV6 channels
Authors: Nakaya Kazuhiro , Harbidge Donald G. , Wangemann Philine , Schultz Bruce D. , Green Eric D. , Wall Susan M. , Marcus Daniel C.
Published: January 2007

The low Ca2+concentration ([Ca2+]) of mammalian endolymph in the inner ear is required for normal hearing and balance. We reported (Yamauchi et al., Biochem Biophys Res Commun 331: 1353–1357, 2005) that the epithelial Ca2+channels TRPV5 and TRPV6 (transient receptor potential types 5 and 6) are expressed in the vestibular system and that TRPV5 expression is stimulated by 1,25-dihydroxyvitamin D3, as also reported in kidney. TRPV5/6 channels are known to be inhibited by extracellular acidic pH. Endolymphatic pH, [Ca2+], and transepithelial potential of the utricle were measured in Cl−/HCO3−exchanger pendrin ( SLC26A4) knockout mice in vivo. Slc26a4−/−mice exhibit reduced pH and utricular endolymphatic potential and increased [Ca2+]. Monolayers of primary cultures of rat semicircular canal duct cells were grown on permeable supports, and cellular uptake of45Ca2+was measured individually from the apical and basolateral sides. Net uptake of45Ca2+was greater after incubation with 1,25-dihydroxyvitamin D3. Net45Ca2+absorption was dramatically inhibited by low apical pH and was stimulated by apical alkaline pH. Gadolinium, lanthanum, and ruthenium red reduced apical uptake. These observations support the notion that one aspect of vestibular dysfunction in Pendred syndrome is a pathological elevation of endolymphatic [Ca2+] due to luminal acidification and consequent inhibition of TRPV5/6-mediated Ca2+absorption.
Swallowing function and upper airway sensation in obstructive sleep apnea
Authors: Jobin Vincent , Champagne Victoria , Beauregard Josée , Charbonneau Isabelle , McFarland David H. , Kimoff R. John
Published: December 2006

The objective of this study was to determine whether impaired upper airway (UA) mucosal sensation contributes to altered swallowing function in obstructive sleep apnea (OSA). We determined UA two-point discrimination threshold (2PDT) and vibratory sensation threshold (VST) in 15 men with untreated OSA and 9 nonapneic controls (CL). We then assessed swallowing responses to oropharyngeal fluid boluses delivered via a catheter. The threshold volume required to provoke swallowing and the mean latency to swallowing were determined, as was the phase of the respiratory cycle in which swallowing occurred [expressed as percentage of control cycle duration (%CCD)] and the extent of prolongation of the respiratory cycle after swallowing [inspiratory suppression time (IST)]. 2PDT and VST were significantly impaired in OSA patients compared with CL subjects. 2PDT was positively correlated with swallowing latency and threshold volume in CL subjects, but not in OSA patients. Threshold volume did not differ between the groups [median value = 0.1 ml (95% confidence interval = 0.1–0.2) for OSA and 0.15 ml (95% confidence interval = 0.1–0.16) for CL], whereas swallowing latency was shorter for OSA patients [3.3 (SD 0.7) vs. 3.9 (SD 0.8) s, P = 0.04]. %CCD and IST were similar for OSA patients and CL subjects. However, among OSA patients there was a significant inverse relation between VST and IST. These findings suggest that oropharyngeal sensory impairment in OSA is associated with an attenuation of inhibitory modulating inputs to reflex and central control of UA swallowing function.
Modulation of Voltage-Gated Ca2+Current in Vestibular Hair Cells by Nitric Oxide
Authors: Almanza Angélica , Navarrete Francisco , Vega Rosario , Soto Enrique
Published: December 2006

The structural elements of the nitric oxide–cyclic guanosine monophosphate (NO–cGMP) signaling pathway have been described in the vestibular peripheral system. However, the functions of NO in the vestibular endorgans are still not clear. We evaluated the action of NO on the Ca2+currents in hair cells isolated from the semicircular canal crista ampullaris of the rat (P14–P18) by using the whole cell and perforated-cell patch-clamp technique. The NO donors 3-morpholinosydnonimine (SIN-1), sodium nitroprusside (SNP), and (±)-(E)-4-ethyl-2-[(Z)-hydroxyimino]-5-nitro-3-hexen-1-yl-nicotinamide (NOR-4) inhibited the Ca2+current in hair cells in a voltage-independent manner. The NO scavenger 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (CPTIO) prevented the inhibitory effect of SNP on the Ca2+current. The selective inhibitor of the soluble form of the enzyme guanylate cyclase (sGC), 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ), also decreased the SNP-induced inhibition of the Ca2+current. The membrane-permeant cGMP analogue 8-Br-cGMP mimicked the SNP effect. KT-5823, a specific inhibitor of cGMP-dependent protein kinase (PGK), prevented the inhibition of the Ca2+current by SNP and 8-Br-cGMP. In the presence of N-ethylmaleimide (NEM), a sulfhydryl alkylating agent that prevents the S-nitrosylation reaction, the SNP effect on the Ca2+current was significantly diminished. These results demonstrated that NO inhibits in a voltage-independent manner the voltage-activated Ca2+current in rat vestibular hair cells by the activation of a cGMP-signaling pathway and through a direct action on the channel protein by a S-nitrosylation reaction. The inhibition of the Ca2+current by NO may contribute to the regulation of the intracellular Ca2+concentration and hair-cell synaptic transmission.
Caveolin 1 Is Overexpressed and Amplified in a Subset of Basal-like and Metaplastic Breast Carcinomas: A Morphologic, Ultrastructural, Immunohistochemical, and In situ Hybridization Analysis
Authors: Savage Kay , Lambros Maryou B.K. , Robertson David , Jones Robin L. , Jones Chris , Mackay Alan , James Michelle , Hornick Jason L. , Pereira Emilio M. , Milanezi Fernanda , Fletcher Christopher D.M. , Schmitt Fernando C. , Ashworth Alan , Reis-Filho Jorge S.
Published: January 2007

Purpose: The distribution and significance of caveolin 1 (CAV1) expression in different breast cell types and role in breast carcinogenesis remain poorly understood. Both tumor-suppressive and oncogenic roles have been proposed for this protein. The aims of this study were to characterize the distribution of CAV1 in normal breast, benign breast lesions, breast cancer precursors, and metaplastic breast carcinomas; to assess the prognostic significance of CAV1 expression in invasive breast carcinomas; and to define whether CAV1 gene amplification is the underlying genetic mechanism driving CAV1 overexpression in breast carcinomas.

Experimental Design: CAV1 distribution in frozen and paraffin-embedded whole tissue sections of normal breast was evaluated using immunohistochemistry, immunofluorescence, and immunoelectron microscopy. CAV1 expression was immunohistochemically analyzed in benign lesions, breast cancer precursors, and metaplastic breast carcinomas and in a cohort of 245 invasive breast carcinomas from patients treated with surgery followed by anthracycline-based chemotherapy. In 25 cases, CAV1 gene amplification was assessed by chromogenic in situ hybridization.

Results: In normal breast, CAV1 was expressed in myoepithelial cells, endothelial cells, and a subset of fibroblasts. Luminal epithelial cells showed negligible staining. CAV1 was expressed in 90% of 39 metaplastic breast carcinomas and in 9.4% of 245 invasive breast cancers. In the later cohort, CAV1 expression was significantly associated with ‘basal-like’ immunophenotype and with shorter disease-free and overall survival on univariate analysis. CAV1 gene amplification was found in 13% of cases with strong CAV1 expression.

Conclusions: The concurrent CAV1 amplification and overexpression call into question its tumor-suppressive effects in basal-like breast carcinomas.
Pathologic and Molecular Heterogeneity in Imatinib-Stable or Imatinib-Responsive Gastrointestinal Stromal Tumors
Authors: Agaram Narasimhan P. , Besmer Peter , Wong Grace C. , Guo Tianhua , Socci Nicholas D. , Maki Robert G. , DeSantis Diann , Brennan Murray F. , Singer Samuel , DeMatteo Ronald P. , Antonescu Cristina R.
Published: January 2007

Purpose: Gastrointestinal stromal tumor (GIST) is the most common sarcoma of the intestinal tract. Nearly all tumors express KIT protein, and most have an activating mutation in either KIT or PDGFRA. Therapy with selective tyrosine kinase inhibitors achieves a partial response or stable disease in ∼80% of patients with advanced GIST. However, after an initial clinical response, some patients develop imatinib resistance. Our goal was to investigate the spectrum of pathologic response and molecular alterations in a group of GIST patients, clinically defined as having imatinib-stable/imatinib-responsive lesions, who underwent surgical resection.

Experimental Design: Forty-three tumor nodules from 28 patients were available for pathologic and molecular analysis, which included genotyping for primary and secondary KIT/PDGFRA-mutations, cell cycle alterations, and biochemical activation status of KIT and downstream targets. The transcriptional changes of a subset of these tumors were compared with a group of imatinib-naive GISTs on a U133A Affymetrix expression platform.

Results: The histologic response did not correlate with imatinib therapy duration or with proliferative activity. Second-site KIT mutation was identified in only one tumor nodule. Activation of KIT and downstream targets was consistent in all tumors analyzed. Ultrastructurally, a subset of tumors showed a smooth muscle phenotype, which correlated with overexpression of genes involved in muscle differentiation and function.

Conclusions: The histologic response to imatinib is heterogeneous and does not correlate well with clinical response. Second-site KIT mutations are rare in imatinib-responsive GISTs compared with imatinib-resistant tumors. The gene signature of imatinib-response in GISTs showed alterations of cell cycle control as well as up-regulation of genes involved in muscle differentiation and function.
Elevated Homocysteine Is Associated With Reduced Regional Left Ventricular Function
Authors: Nasir Khurram , Tsai Michael , Rosen Boaz D. , Fernandes Veronica , Bluemke David A. , Folsom Aaron R. , Lima João A.C.
Published: January 2007

Background—

An elevated homocysteine (Hcy) level has been reported to be a risk factor for the development of congestive heart failure in individuals free of myocardial infarction. In this study, we aim to investigate the relationship between Hcy levels and regional left ventricular function in an asymptomatic population.

Method and Results—

Regional peak systolic midwall circumferential strains were calculated from 1178 tagged magnetic resonance imaging studies in participants in the Multi-Ethnic Study of Atherosclerosis (MESA). Left ventricular regions were defined by coronary territories (left anterior descending, left circumflex, right coronary artery). For the 1178 study participants (66±10 years of age, 58% males), the median (interquartile range) of Hcy was 9.1 (9.0 to 9.3). After adjustment for traditional risk factors, race, height, weight, left ventricular end-diastolic mass/volume, serum creatinine, and measures of atherosclerosis, reduced regional myocardial circumferential shortening across sex-specific quartiles of plasma Hcy in the left anterior descending (
P
=0.038) and left circumflex (
P
=0.009) regions persisted, which indicated an important association of reduced function with elevated Hcy. Multiple linear regression analyses confirmed that circumferential systolic dysfunction was associated with log transformed Hcy levels in the left anterior descending (
P
=0.004) and left circumflex (
P
=0.0002) regions. In the fully adjusted model, the odds ratio for left ventricular strains below the 10
th
percentile with 1 SD increases in log-transformed Hcy was 1.33 (95% confidence interval, 1.04 to 1.70;
P
=0.022) for the left anterior descending, 1.28 (95% confidence interval, 1.00 to 1.64;
P
=0.046) for the left circumflex, and 1.32 (95% confidence interval, 1.03 to 1.69;
P
=0.025) for the right coronary artery region.

Conclusion—

In this asymptomatic population, an elevated Hcy level is associated with reduced regional left ventricular systolic function detected by tagged magnetic resonance imaging.
Rapid Detection of Myocardial Infarction by Subsecond, Free-Breathing Delayed Contrast-Enhancement Cardiovascular Magnetic Resonance
Authors: Sievers Burkhard , Elliott Michael D. , Hurwitz Lynne M. , Albert Timothy S.E. , Klem Igor , Rehwald Wolfgang G. , Parker Michele A. , Judd Robert M. , Kim Raymond J.
Published: January 2007

Background—

An ultrafast, delayed contrast-enhancement cardiovascular magnetic resonance technique that can acquire subsecond, “snapshot” images during free breathing (subsecond) is becoming widely available. This technique provides myocardial infarction (MI) imaging with complete left ventricular coverage in <30 seconds. However, the accuracy of this technique is unknown.

Methods and Results—

We prospectively compared subsecond imaging with routine breath-hold delayed contrast-enhancement cardiovascular magnetic resonance (standard) in consecutive patients. Two cohorts with unambiguous standards of truth were prespecified: (1) patients with documented prior MI (n=135) and (2) patients without MI and with low likelihood of coronary disease (lowest Framingham risk category; n=103). Scans were scored masked to identity and clinical information. Sensitivity, specificity, and accuracy of subsecond imaging for MI diagnosis were 87%, 96%, and 91%, respectively. Compared with the standard technique (98%, 100%, 99%), the subsecond technique had modestly reduced sensitivity (
P
=0.0001), but specificity was excellent. Missed infarcts were generally small or subendocardial (87%). Overall, regional transmural extent of infarction scores were highly concordant (2083/2294; 91%); however, 51 of 337 regions (15%) considered predominantly infarcted (>50% transmural extent of infarction) by the standard technique were considered viable (≤25% transmural extent of infarction) by the subsecond technique. Quantitative analysis demonstrated moderately reduced contrast-to-noise ratios for subsecond imaging between infarct and remote myocardium (12.0±7.2 versus 20.1±6.6;
P
<0.0001) and infarct and left ventricular cavity (−2.5±2.7 versus 3.6±3.7;
P
<0.0001).

Conclusions—

MI can be rapidly detected by subsecond delayed contrast-enhancement cardiovascular magnetic resonance during free breathing with high accuracy. This technique could be considered the preferred approach in patients who are more acutely ill or unable to hold their breath. However, compared with standard imaging, sensitivity is mildly reduced, and the transmural extent of infarction may be underestimated.
Cardiac Tissue Engineering in an In Vivo Vascularized Chamber
Authors: Morritt Andrew N. , Bortolotto Susan K. , Dilley Rodney J. , Han XiaoLian , Kompa Andrew R. , McCombe David , Wright Christine E. , Itescu Silviu , Angus James A. , Morrison Wayne A.
Published: January 2007

Background—

Cardiac tissue engineering offers the prospect of a novel treatment for acquired or congenital heart defects. We have created vascularized pieces of beating cardiac muscle in the rat that are as thick as the adult rat right ventricle wall.

Method and Results—

Neonatal rat cardiomyocytes in Matrigel were implanted with an arteriovenous blood vessel loop into a 0.5-mL patented tissue-engineering chamber, located subcutaneously in the groin. Chambers were harvested 1, 4, and 10 weeks after insertion. At 4 and 10 weeks, all constructs that grew in the chambers contracted spontaneously. Immunostaining for α-sarcomeric actin, troponin, and desmin showed that differentiated cardiomyocytes present in tissue at all time points formed a network of interconnected cells within a collagenous extracellular matrix. Constructs at 4 and 10 weeks were extensively vascularized. The maximum thickness of cardiac tissue generated was 1983 μm. Cardiomyocytes increased in size from 1 to 10 weeks and were positive for the proliferation markers Ki67 and PCNA. Connexin-43 stain indicated that gap junctions were present between cardiomyocytes at 4 and 10 weeks. Echocardiograms performed between 4 and 10 weeks showed that the tissue construct contracted spontaneously in vivo. In vitro organ bath experiments showed a typical cardiac muscle length-tension relationship, the ability to be paced from electrical field pulses up to 3 Hz, positive chronotropy to norepinephrine, and positive inotropy in response to calcium.

Conclusion—

In summary, the use of a vascularized tissue-engineering chamber allowed generation of a spontaneously beating 3-dimensional mass of cardiac tissue from neonatal rat cardiomyocytes. Further development of this vascularized model will increase the potential of cardiac tissue engineering to provide suitable replacement tissues for acquired and congenital defects.
Accountability and Local Control: Response to Incentives with and without Authority over Resource Generation and Allocation
Authors: Loeb Susanna , Strunk Katharine
Published: December 2006

This article examines the interaction between school accountability and local control over revenue raising and resource allocation. In particular, it asks whether accountability policies are more or less effective at improving student outcomes in states with stronger local control. Local control is operationalized with multiple measures, including the percentage of education funding from categorical grants, state supreme court rulings overturning school finance systems, local entities' taxing authority, and principals' self-assessments of their ability to control school resources. Using the National Center for Education Statistics' Schools and Staffing Survey and National Assessment of Educational Progress, the article finds that accountability policies are more effective when there is greater local control.
Constructing a Developmental Nation: The Challenges of Science, Technology, and Innovation in the Socioeconomic Transformation of Africa
Authors: Forje John
Published: December 2006

The major challenge facing Africa's socioeconomic transformation pivots on the gross absence of added value to its abundant natural resources. The continent is suffering from low human resources development, poor innovative capacity, and low productivity. This paper argues that, until the continent is able to develop its innovative, competitive, productive, and competence capacity, it will remain an underdeveloped polity exploited by the countries that master the driving forces of science, technology, research, innovation, and globalization in the development process.
Aid and Economic Growth in Pacific Island Countries: An Empirical Study of Aid Effectiveness in Fiji
Authors: Jayaraman  , Choong Chee-Keong
Published: December 2006

Pacific island countries (PICs), ever since their independence during the second half of the last century, have been among the world's top ten recipients of official development assistance (ODA) on a per capita basis. Until the mid 1990s, most of them were receiving aid from their erstwhile colonial masters for budgetary support. With the introduction of reforms in ODA delivery in the late 1990s with focus on program and project-tied aid, it was expected that aid would directly facilitate creation of much-needed growth enhancing infrastructures, physical as well as social, since domestic savings were found to be insufficient to finance them. However, continued stagnation in some PICs and deterioration in some others have been causing concerns. This paper seeks to examine the effectiveness of aid by undertaking a case study of Fiji, which has a longer time series data needed for econometric investigation. Based on the study's findings, the paper lists some policy conclusions relevant to the region.
International Training and the Digital Divide: Computer and Email Use in the Philippines
Authors: Ynalvez Marcus , Shrum Wesley
Published: December 2006

We describe digital technology utilization among knowledge producers who have experienced the alternative training structures. Using data from a face-to-face survey of Filipino scientists, we measure email utilization by scientists in terms of five aspects of access and use, and examine how they vary across place of graduate education. Our questions are: (1) How can we characterize peripheral scientists in terms of their contextual, personal, professional, and educational attributes? (2) How can we characterize their utilization of digital technology? (3) Are there indications that core-based graduate training translates into yet another significant dimension in digital inequality? Our finding suggests that the Philippine scientific system largely reflects the perspective of core-trained male scientists. Filipino scientists are able to utilize digital technology—personal computers, email, and the World Wide Web—but with important qualifications. While scientists at the core have the luxury of architectural, digital, and personal privacy in hardware-software-user interaction, such is not the case for Filipino scientists, who in general have to share digital resources in public spaces within formal organizations. Finally, place of graduation emerges as a new form shaping digital utilization and inequality. The diffusion of digital technology into peripheral scientific systems has been uneven along this newly emerging dimension. Digital inequality construed as simple hardware-software access and use is diminishing, but inequality at the level of advanced hardware-software interaction skills is fast emerging as a new dimension that encapsulates postcolonial relations in science.
On the Use of Quasi-crystal and Fractal Concepts in the Design of Affordable Rural/Urban Landscapes
Authors: Niang  , Soboyejo
Published: December 2006

This paper describes the use of quasi-crystal and fractal concepts in the design of rural and urban landscapes for affordable housing. These are shown to provide a framework for the efficient design of communities in which affordable homes are organized. In contrast to classical urban planning with single centers, distributed centers are integrated into the rural and urban landscapes using crystallographic and fractal concepts. These provide a framework for the dispersion of human traffic into well-identified regions. The combination of quasi-crystal and fractal theory is also used to provide a framework for the organic growth of communities around new distributed centers. These basic ideas are discussed within the context of a holistic framework for affordable housing.
On the Nature of Zonal Jet EOFs
Authors: Monahan Adam H. , Fyfe John C.
Published: December 2006

Analytic results are obtained for the mean and covariance structure of an idealized zonal jet that fluctuates in strength, position, and width. Through a systematic perturbation analysis, the leading empirical orthogonal functions (EOFs) and principal component (PC) time series are obtained. These EOFs are built of linear combinations of basic patterns corresponding to monopole, dipole, and tripole structures. The analytic results demonstrate that in general the individual EOF modes cannot be interpreted in terms of individual physical processes. In particular, while the dipole EOF (similar to the leading EOF of the midlatitude zonal mean zonal wind) describes fluctuations in jet position to leading order, its time series also contains contributions from fluctuations in strength and width. No simple interpretations of the other EOFs in terms of strength, position, or width fluctuations are possible. Implications of these results for the use of EOF analysis to diagnose physical processes of variability are discussed.
Comparison of Five Satellite-Derived Latent Heat Flux Products to Moored Buoy Data
Authors: Bourras Denis
Published: December 2006

Five satellite products of latent heat flux at the sea surface were compared to bulk fluxes calculated with data from 75 moored buoys, on almost 36 successive months from 1998 to 2000. The five products compared are the Hamburg Ocean Atmosphere Parameters and Fluxes from Satellite Dataset (HOAPS-2), the Japanese Ocean Flux Datasets with Use of Remote Sensing Observations (J-OFURO), the Jones dataset, the Goddard Satellite-Based Surface Turbulent Fluxes, version 2 (GSSTF-2), and the Bourras–Eymard–Liu dataset (BEL). The comparisons were performed under tropical and midlatitude environmental conditions, with three datasets based on 66 Tropical Atmosphere–Ocean array (TAO) buoys in the tropical Pacific, nine National Data Buoy Center (NDBC) buoys off the U.S. coasts, and four Met Office/Météo-France (UK–MF) moorings west of the United Kingdom and France, respectively. The satellite products did not all compare well to surface data. However, for each in situ dataset (TAO, NDBC, or UK–MF) at least one satellite product was found that had a good fit to surface data, that is, an rms deviation of 15–30 W m−2. It was found that HOAPS-2, J-OFURO, GSSTF-2, and BEL satellite products had moderate systematic errors with respect to surface data, from −13 to 26 W m−2, and small biases at midlatitudes (6–8 W m−2). Most of the satellite products were able to render the seasonal cycle of the latent heat flux calculated with surface data. The estimation of near-surface specific humidity was found to be problematic in most products, but it was best estimated in the HOAPS-2 product. GSSTF-2 and J-OFURO strongly overestimated the surface flux variations in time and space compared to surface data and to a flux climatology. With respect to TAO data, Jones fluxes yielded good results in terms of rms deviation (27 W m−2) but also presented a large systematic deviation. Overall, for application of the satellite fluxes to the world oceans, it was found that HOAPS-2 was the most appropriate product, whereas for application to the Tropics, BEL fluxes had the best performance in rms with respect to TAO data (24 W m−2).
Interactive Feedback between ENSO and the Indian Ocean in an Interactive Ensemble Coupled Model
Authors: Kug Jong-Seong , Kirtman Ben P. , Kang In-Sik
Published: December 2006

An interactive feedback between ENSO and the Indian Ocean is investigated using a Center for Ocean–Land–Atmosphere Studies (COLA) interactive ensemble coupled model. From a long-term simulation of the coupled GCM, it is shown that El Niño events terminate relatively rapidly when the Indian Ocean SST is anomalously warm. The anomalous Indian Ocean warming induces the anomalous easterlies over the western Pacific by modulating the Walker circulation. In turn, the anomalous easterlies generate oceanic-upwelling Kelvin waves over the western Pacific, which propagate eastward and accelerate the decay of the warm SST in the eastern Pacific. As a result, El Niño terminates relatively quickly, and the phase transition from El Niño to La Niña progresses rapidly. These interactive processes are consistent with those derived from the previous observational analyses.
Social Closure and Processes of Race/Sex Employment Discrimination
Authors: Roscigno Vincent J. , Garcia Lisette M. , Bobbitt-Zeher Donna
Published: December 2006

Research on race and gender inequalities in employment typically infers discrimination as an important causal mechanism. The authors' systematic explication of social closure as a discriminatory mechanism reveals that traditional analyses of structural effects and process are not competing, but rather complementary. Analyzing race and sex discrimination cases filed in Ohio from 1988 to 2003, the authors highlight dominant processes of social closure that impact discriminatory exclusion, expulsion, mobility, and harassment on the job. Rather than employing the typical cause and effect modeling centering on outcomes, qualitative analyses serve to clarify discriminatory processes at play. Commonalities between race and sex (e.g., particularistic criteria in evaluation) emerge, as do specific racialized and gendered processes. The authors discuss similarities and differences in process; tie qualitative insights to the existing literature; and discuss the implications of their results for theoretical formulations of structure, agency, and inequality within institutional/ organizational environments and society at large.
Racialized Life-Chance Opportunities across the Class Structure: The Case of African Americans
Authors: Wilson George
Published: December 2006

Considerations of how socioeconomic outcomes are racialized within discrete class categories have been neglected in assessing the race/class determinants of life-chance opportunities of African Americans. This article addresses this shortcoming. Specifically, it synthesizes findings from recent sociological research concerning how segregation in two institutional spheres, residence and employment, produce racialization at two class levels— among the impoverished and the middle class. The article documents that segregation plays a significant role in producing racial inequality at both class levels, though it exerts different influences across class categories: at the impoverished level, segregation in the residential sphere, and at the middle-class level, segregation in the employment sphere, emerge as critical underpinnings of African Americans’ inferior life-chance opportunities. The implications of the findings for using traditional Weberian and Marxist modes of class analyses in assessing the life-chance opportunities for African Americans as well as how the findings contribute to the resolution of the race/class debate are discussed.
Propofol Use in Pediatric Patients With Severe Cancer Pain at the End of Life
Authors: Hooke Mary C. , Grund Erin , Quammen Heather , Miller Blaine , McCormick Paul , Bostrom Bruce
Published: December 2006

This article describes the use and effectiveness of adjuvant propofol for pain control for pediatric oncology patients at the end of life. All patients experienced severe pain and agitation, not well controlled by continuous infusion opioids and benzodiazepines. Upon starting propofol, most patients had a temporary stabilization in the dose of opioids with subjective improvement in pain control, increased alertness, and improved ability to interact. Propofol infusions were continued until death in most patients. Two patients received propofol infusions at home. Subsequent increases in opioids in 6 patients and propofol in all patients were required for optimal pain control. Adverse effects included agitation in 5 patients and hallucinations in 2, which were controllable with benzodiazepines. One patient developed severe tetany, requiring propofol interruption; propofol was successfully restarted at a lower dose with an adjuvant benzodiazepine. The authors conclude that propofol is a useful and tolerable adjuvant agent for pain management in pediatric oncology patients at the end of life. It is a useful adjuvant if pain is unresponsive to continuous infusion opioids or if rapidly escalating doses of opioids are required.
Cystic fibrosis mortality and survival in the UK: 1947–2003
Authors: Dodge J. A. , Lewis P. A. , Stanton M. , Wilsher J.
Published: December 2006

Data up to 1995 on the survival of 3-yr cohorts of patients with cystic fibrosis (CF) born in the UK in the period 1968–1992 have previously been published. The present study reports survival data up to the end of 2003 together with a 2003 population estimate.

All subjects with CF born in the UK in the period 1968–1992 were identified up to 1997 by active enquiry through recognised CF clinics and other hospital consultants. Information from the death certification authorities up to the end of 2003 was added. Death certificates that could not be matched with UK Cystic Fibrosis Survey records were investigated and the data reconciled.

The observed survival up to 2003 of CF patients born in 1978 was 55% for males and 49% for females. For 1988 and 1992 the data were 91 and 88%, and 97 and 96%, respectively. The estimated 2003 mid-year CF population was 8,284.

The continuing improvement in survival of cystic fibrosis patients in successive cohorts means that the previous prediction of median survival of >50 yrs of age for individuals born in 2000 continues to look realistic, even in the absence of proven effective therapy aimed at correcting the basic cystic fibrosis defect.