bluuebunny/crossref_metadata_2025 huggingface dataset:
La végétation postglaciaire du Témiscamingue, Québec, durant l'épisode glaciolacustre Barlow
Authors: Richard Pierre J. H. , Larouche Alayn C.
Published: October 2007

The 14C ages of the basal organic deposits accumulated in 32 small lakes located higher than or near the altitudinal limit of proglacial Lake Barlow, in Témiscamingue, span the period between 10400 and 6490 years BP. A regional pollen zonation has been established, allowing the rejection of the 14C ages younger than 8500 years BP, as minimum ages for local ice retreat. From 10400 to 8500 BP, whatever the age of the lake, the same general sequence of vegetation has spread over the deglaciated landscapes. The initial vegetation was dominated by Picea and Larix (pollen, macrofossils) and included Quercus, Ostrya, Ulmus, and Fraxinus (pollen influxes equal or greater than what they are today) along with plants having a present-day mainly arctic distribution such as Dryas integrifolia and Silene acaulis (macrofossils). The initial proglacial vegetational environment on the islands or around Lake Barlow was thus an open conifer forest with arctic plants and groves of relatively thermophilous deciduous trees, whatever the age of the onset of sediment accumulation in the lakes studied, between 10400 and 8500 years BP. After the initial vegetation was established and within a few centuries, Betula papyrifera, Populus tremuloides, Populus balsamifera, Pinus banksiana, and Abies balsamea (macrofossils, pollen) joined the other trees around each lake, whatever the age or location.
Vascular coating: a barrier to colonization by the pathogen in Verticillium wilt of tomato
Authors: Robb Jane , Powell D. A. , Street P. F. S.
Published: October 2007

Massive infusion of conidia of Verticillium albo-atrum Reinke & Berthier induced synchronous secretion of vascular coating in the petiolar xylem vessels of resistant and susceptible tomato near-isolines. More coating formed earlier in resistant than in susceptible plants. In the susceptible plants secretion was delayed in colonized trapping site vessels, but initiated in surrounding uncolonized ones. Controls were infused with water. Samples were quantified by light microscope assay techniques at 18, 48, and 120 h postinoculation for the following parameters: (i) delayed coating effect, (ii) overall coating capacity, and (iii) ability of fungus to "escape" laterally from trapping site vessels. The results showed that susceptibility to Verticillium was absolutely correlated with the presence of the delayed coating effect in the plant and increased ability of the fungus to spread laterally. Treatment of inoculated resistant plants with an inhibitor of coating secretion resulted in conversion to the susceptible phenotype. The progeny of a genetic backcross for the dominant (Ve) and recessive (ve) alleles at the Ve locus (Velve × velve) were assayed for the same parameters as well as for disease resistance based on symptom expression. The results confirmed the previous observations and suggested that in tomato the delayed phenotype is recessive. The data strongly supports two hypotheses: (i) coating forms a barrier against fungal penetration and (ii) the timing of the coating response in trapping site vessels results, directly or indirectly, from expression of the Ve gene.
Histologie des méristèmes d'accroissement diamétral primaire et secondaire et de leurs dérivés chez le Cordyline indivisa (Agavacées)
Authors: Laliberté Sylvie , Vieth Joachim
Published: October 2007

In Cordyline indivisa Kunth, the primary and secondary thickening meristems of 16- to 18-month-old specimens are continuous, but in cross sections, they show different histological features. Their respective provascular bundles differ in their appearance, the way they are produced, and the way they differentiate. A transition zone, which extends longitudinally for about 2 mm, is characterized by the simultaneous presence of the two meristems. In cross sections, the first periclinal divisions of the secondary meristem are seen (i) in the primary meristem, (ii) in the adjacent cortical parenchyma, and (iii) in regions where the meristematic ring is interrupted. Structural continuity between the two meristems is responsible for the presence of primary bundles which extend basipetally as secondary bundles.
Statin reverses reduction of adiponectin receptor expression in infarcted heart and in TNF-α-treated cardiomyocytes in association with improved glucose uptake
Authors: Saito Yukio , Fujioka Daisuke , Kawabata Ken-ichi , Kobayashi Tsuyoshi , Yano Toshiaki , Nakamura Takamitsu , Kodama Yasushi , Takano Hajime , Kitta Yoshinobu , Obata Jyun-ei , Kugiyama Kiyotaka
Published: September 2007

Statin treatment improves insulin resistance in skeletal muscle. Thus this study assessed whether statin may affect the myocardial expression levels of AdipoR1 and AdipoR2, receptors of adiponectin that enhance insulin sensitivity, and whether statin may improve insulin resistance in cardiomyocytes. Myocardial infarction (MI) was created by the ligation of the left coronary artery in male mice. Expression levels of mRNA and protein levels of AdipoR1 but not of AdipoR2 were significantly decreased in the remote area as well as in the healed infarcted area in the left ventricles 4 wk after MI. Oral administration of pravastatin (50 mg·kg−1·day−1 for 4 wk after MI) reversed the decrease in myocardial expression levels of AdipoR1 independently of changes in serum lipid profiles and insulin levels. With the use of cultured cardiomyocytes, incubation with tumor necrosis factor (TNF)-α, a mediator of postinfarction myocardial dysfunction, inhibited AdipoR1 mRNA and protein expression levels. Coincubation of the cells with pravastatin reversed the inhibitory effects of TNF-α on AdipoR1 expression. In parallel, pravastatin reversed the TNF-α-induced decrease in globular adiponectin-induced 2-deoxy-d-[3H]glucose uptake in insulin-treated cultured cells. Moreover, this effect of pravastatin was inhibited by the suppression of AdipoR1 expression by small-interfering RNA specific for AdipoR1. Incubation with H2O2 reduced AdipoR1 expression in cultured cardiomyocytes that were attenuated by N-acetyl-l-cysteine or pravastatin. Pravastatin suppressed TNF-α-induced intracellular oxidants in cultured cardiomyocytes. In conclusion, pravastatin reversed the reduction of AdipoR1 expression in postinfarction mouse myocardium and in TNF-α-treated cardiomyocytes partly through an antioxidative mechanism in association with improved glucose uptake.
Decreased capillary filtration but maintained venous compliance in the lower limb of aging women
Authors: Lindenberger Marcus , Länne Toste
Published: September 2007

There are sex-related differences in venous compliance and capillary filtration in the lower limbs, which to some extent can explain the susceptibility to orthostatic intolerance in young women. With age, venous compliance and capacitance are reduced in men. This study was designed to evaluate age-related changes in venous compliance and capillary filtration in the lower limbs of healthy women. Included in this study were 22 young and 12 elderly women (23.1 ± 0.4 and 66.4 ± 1.4 yr). Lower body negative pressure (LBNP) of 11, 22, and 44 mmHg created defined transmural pressure gradients in the lower limbs. A plethysmographic technique was used on the calf to assess venous capacitance and net capillary filtration. Venous compliance was calculated with the aid of a quadratic regression equation. No age-related differences in venous compliance and capacitance were found. Net capillary filtration and capillary filtration coefficient (CFC) were lower in elderly women at a LBNP of 11 and 22 mmHg (0.0032 vs. 0.0044 and 0.0030 vs. 0.0041 ml·100 ml−1·min−1·mmHg−1, P < 0.001). At higher transmural pressure (LBNP, 44 mmHg), CFC increased by ∼1/3 (0.010 ml·100 ml−1·min−1·mmHg−1) in the elderly ( P < 0.001) but remained unchanged in the young women. In conclusion, no age-related decrease in venous compliance and capacitance was seen in women. However, a decreased CFC was found with age, implying reduced capillary function. Increasing transmural pressure increased CFC in the elderly women, indicating an increased capillary susceptibility to transmural pressure load in dependent regions. These findings differ from earlier studies on age-related effects in men, indicating sex-specific vascular aging both in the venous section and microcirculation.
Carboxypeptidase B and other kininases of the rat coronary and mesenteric arterial bed perfusates
Authors: Oliveira Eduardo B. , Souza Laura L. , Sivieri Disney O. , Bispo-da-Silva Luiz B. , Pereira Hugo J. V. , Costa-Neto Claudio M. , Sousa Marcelo V. , Salgado Maria Cristina O.
Published: September 2007

We describe the enzymes that constitute the major bradykinin (BK)-processing pathways in the perfusates of mesenteric arterial bed (MAB) and coronary vessels isolated from Wistar normotensive rats (WNR) and spontaneously hypertensive rats. The contribution of particular proteases to BK degradation was revealed by the combined analysis of fragments generated during incubation of BK with representative perfusate samples and the effect of selective inhibitors on the respective reactions. Marked differences were seen among the perfusates studied; MAB secretes, per minute of perfusion, kininase activity capable of hydrolyzing ∼300 pmol of BK/min, which is ∼250-fold larger amount on a per unit time basis than that of its coronary counterpart. BK degradation in the coronary perfusate seems to be mediated by ANG I-converting enzyme, neutral endopeptidase 24.11-like enzyme, and a dl-2-mercaptomethyl-3-guanidinoethylthiopropanoic acid-sensitive basic carboxypeptidase; coronary perfusate of WNR contains an additional BK-degrading enzyme whose specificity resembles that of neurolysin or thimet oligopeptidase. Diversely, a des-Arg9-BK-forming enzyme, responsible for nearly all of the kininase activity of MAB perfusates of WNR and spontaneously hypertensive rats, could be purified by a procedure that involved affinity chromatography over potato carboxypeptidase inhibitor-Sepharose column and shown to be structurally identical to rat pancreatic carboxypeptidase B (CPB). Comparable levels of CPB mRNA expression were observed in pancreas, liver, mesentery, and kidney, but very low levels were detected in lung, heart, aorta, and carotid artery. In conclusion, distinct BK-processing pathways operate in the perfusates of rat MAB and coronary bed, with a substantial participation of a des-Arg9-BK-forming enzyme identical to pancreatic CPB.
The AMPK γ1 R70Q mutant regulates multiple metabolic and growth pathways in neonatal cardiac myocytes
Authors: Folmes Karalyn D. , Witters Lee A. , Allard Michael F. , Young Martin E. , Dyck Jason R. B.
Published: September 2007

Although mutations in the γ-subunit of AMP-activated protein kinase (AMPK) can result in excessive glycogen accumulation and cardiac hypertrophy, the mechanisms by which this occurs have not been well defined. Because >65% of cardiac AMPK activity is associated with the γ1-subunit of AMPK, we investigated the effects of expression of an AMPK-activating γ1-subunit mutant (γ1 R70Q) on regulatory pathways controlling glycogen accumulation and cardiac hypertrophy in neonatal rat cardiac myocytes. Whereas expression of γ1 R70Q displayed the expected increase in palmitate oxidation rates, rates of glycolysis were significantly depressed. In addition, glycogen synthase activity was increased in cardiac myocytes expressing γ1 R70Q, due to both increased expression and decreased phosphorylation of glycogen synthase. The inhibition of glycolysis and increased glycogen synthase activity were correlated with elevated glycogen levels in γ1 R70Q-expressing myocytes. In association with the reduced phosphorylation of glycogen synthase, glycogen synthase kinase (GSK)-3β protein and mRNA levels were profoundly decreased in the γ1 R70Q-expressing myocytes. Consistent with GSK-3β negatively regulating hypertrophy via inhibition of nuclear factor of activated T cells (NFAT), the dramatic downregulation of GSK-3β was associated with increased nuclear activity of NFAT. Together, these data provide important new information about the mechanisms by which a mutation in the γ-subunit of AMPK causes altered AMPK signaling and identify multiple pathways involved in regulating both cardiac myocyte metabolism and growth that may contribute to the development of the γ mutant-associated cardiomyopathy.
Functional genomics of silencing TREM-1 on TLR4 signaling in macrophages
Authors: Ornatowska M. , Azim A. C. , Wang X. , Christman J. W. , Xiao L. , Joo M. , Sadikot R. T.
Published: September 2007

Triggering receptor expressed on myeloid cells 1 (TREM-1) is a recently discovered molecule that is expressed on the cell surface of monocytes and neutrophils. Engagement of TREM-1 triggers synthesis of proinflammatory cytokines in response to microbes, but the extent and mechanism by which TREM-1 modulates the inflammatory response is poorly defined. In the present study, we investigated the functional effects of blocking TREM-1 on the Toll-like receptor (TLR)4-mediated signaling pathway in macrophages. By transfecting cells with small hairpin interfering RNA molecules to TREM-1 (shRNA), we confirmed that TREM-1 mRNA and protein expression was greatly attenuated in RAW cells in response to treatment with LPS. PCR array for genes related to or activated by the TLR pathway revealed that although the expression of TLR4 itself was not significantly altered by silencing of TREM-1, expression of several genes, including MyD88, CD14, IκBα, IL-1β, MCP-1, and IL-10 was significantly attenuated in the TREM-1 knockdown cells in response to treatment with LPS. These data indicate that expression of TREM-1 modulates the TLR signaling in macrophages by altering the expression of both adaptor and effector proteins that are critical to the endotoxin response.
Sodium and asthma: something borrowed, something new?
Authors: Hirota Simon A. , Janssen Luke J.
Published: September 2007

Some early studies have called attention to the potential contribution of sodium (both dietary and serum levels) in airway-related disease, although the picture was not entirely clear. Two recent developments may now allow a more careful consideration of this: first, the greatly improved understanding of the role of salt in hypertension (particularly the identification of subgroups of salt-sensitive individuals within the general population), and second, the recent discovery of the role of the Na+/Ca2+exchanger in smooth muscle function. Here, we first review those two developments and then apply them to airway smooth muscle and asthma.
Could Neutrophil-Gelatinase-Associated Lipocalin and Cystatin C Predict the Development of Contrast-Induced Nephropathy after Percutaneous Coronary Interventions in Patients with Stable Angina and Normal Serum Creatinine Values?
Authors: Bachorzewska-Gajewska H. , Malyszko J. , Sitniewska E. , Malyszko J.S. , Pawlak K. , Mysliwiec M. , Lawnicki S. , Szmitkowski M. , Dobrzycki S.
Published: October 2007

The value of neutrophil-gelatinase-associated lipocalin (NGAL) was highlighted as a novel biomarker for the detection of acute renal failure. We tested the hypothesis whether NGAL could represent an early biomarker of contrast-induced nephropathy (CIN) in 100 patients with normal serum creatinine values undergoing percutaneous coronary interventions (PCI). In addition, we assessed serum and urinary NGAL in relation to cystatin C, estimated glomerular filtration rate, and serum and urinary creatinine in these patients. We measured urinary and serum NGAL values before and 2, 4, 8, 24, and 48 h after the PCI. We found a significant rise in serum NGAL levels 2, 4, and 8 h after the PCI and in urinary NGAL values 4, 8, and 24 h after a PCI procedure. Cystatin C rose significantly 24 h after the procedure. The prevalence of CIN was 11%. The NGAL levels were significantly higher 2 h after the PCI (serum NGAL) or 4 h after the PCI (urinary NGAL), whereas the cystatin C values were higher only 8 and 24 h after a PCI procedure in patients with CIN. In multivariate analysis, only serum creatinine was a predictor of serum NGAL before a PCI. NGAL may represent a sensitive early biomarker of renal impairment after PCI. Serum creatinine level, the presence of diabetes, and the duration of the PCI may affect serum NGAL values and kidney function following a PCI procedure.
CXCR6 Promotes Atherosclerosis by Supporting T-Cell Homing, Interferon-γ Production, and Macrophage Accumulation in the Aortic Wall
Authors: Galkina Elena , Harry Brian L. , Ludwig Andreas , Liehn Elisa A. , Sanders John M. , Bruce Anthony , Weber Christian , Ley Klaus
Published: October 2007

Background—

T lymphocytes are thought to be important in atherosclerosis, but very little is known about the mechanisms of lymphocyte recruitment into atherosclerosis-prone aortas. In this study we tested the hypothesis that CXCR6, a chemokine receptor that is expressed on a subset of CD4
+
T helper 1 cells and natural killer T cells, is involved in lymphocyte homing into the aortic wall and modulates the development and progression of atherosclerosis.

Methods and Results—

To investigate the role of CXCR6 in the development and progression of atherosclerosis, we bred CXCR6-deficient (CXCR6
GFP/GFP
) mice with apolipoprotein E–deficient (ApoE
−/−
) mice. We found that CXCR6

GFP/GFP

/ApoE
−/−
mice fed a Western diet for 17 weeks or a chow diet for 56 weeks had decreased atherosclerosis compared with ApoE
−/−
controls. Flow cytometry analysis of the aortas from CXCR6
GFP/GFP
/ApoE
−/−
mice showed that the reduction of atherosclerosis was accompanied by a decreased percentage of CXCR6
+
T cells within the aortas. Short-term homing experiments demonstrated that CXCR6 is involved in the recruitment of CXCR6
+
leukocytes into the atherosclerosis-prone aortic wall. The reduced percentage of CXCR6
+
T cells within the aortas resulted in significantly diminished production of interferon-γ and reduction of CD11b
+
/CD68
+
macrophages in the aorta.

Conclusions—

These data provide evidence for a proatherosclerotic role of CXCR6. Absence of CXCR6 alters the recruitment of CXCR6
+
leukocytes and modulates the local immune response within the aortic wall.
Hydroclimatic Trends in the Mississippi River Basin from 1948 to 2004
Authors: Qian Taotao , Dai Aiguo , Trenberth Kevin E.
Published: October 2007

The trends of the surface water and energy budget components in the Mississippi River basin from 1948 to 2004 are investigated using a combination of hydrometeorological observations and observation-constrained simulations of the land surface conditions using the latest version of the Community Land Model version 3 (CLM3). The atmospheric forcing data for the CLM3 were constructed by adding the intramonthly variations from the 6-hourly National Centers for Environmental Prediction–National Center for Atmospheric Research (NCEP–NCAR) reanalysis to observation-based analyses of monthly precipitation, surface air temperature, and cloud cover. The model-based analysis suggests that, for the surface water budget, the observed increase in basin-averaged precipitation is compensated by increases in both runoff and evapotranspiration. For the surface energy budget, the decrease of net shortwave radiation associated with observed increases in cloudiness is compensated by decreases in both net longwave radiation and sensible heat flux, while the latent heat flux increases in association with wetter soil conditions. Both the simulated surface water and energy budgets support the view that evapotranspiration has increased in the Mississippi River basin from 1948 to 2004. Sensitivity experiments show that the precipitation change dominates the evapotranspiration trend, while the temperature and solar radiation changes have only small effects. Large spatial variations within the Mississippi River basin and the contiguous United States are also found. However, the increased evapotranspiration is ubiquitous despite spatial variations in hydrometeorology.
Mechanisms of Summertime Subtropical Southern Indian Ocean Sea Surface Temperature Variability: On the Importance of Humidity Anomalies and the Meridional Advection of Water Vapor*
Authors: Chiodi A. M. , Harrison D. E.
Published: October 2007

It is well known that some austral summertime subtropical Indian Ocean sea surface temperature (SST) variability correlates with rainfall over certain regions of Africa that depend on rainfall for their economic well-being. Recent studies have determined that this SST variability is at least partially driven by latent heat flux variability, but the mechanism has not been fully described. Here, the mechanism that drives this SST variability is reexamined using analyses of operational air–sea fluxes, ocean mixed layer modeling, and simple atmospheric boundary layer physics. The SST variability of interest is confirmed to be mainly driven by latent heat flux variability, which is shown, for the first time, to be mainly caused by near-surface humidity variability. This humidity variability is then shown to be fundamentally driven by the anomalous meridional advection of water vapor. The meridional wind anomalies of interest are subsequently found to occur when the subtropical atmospheric anticyclone is preferentially located toward one of the sides (east/west) of the basin.
Influence of Ethnic Origin and Sex on the Pharmacokinetics of Clazosentan
Authors: van Giersbergen Paul L. M. , Gunawardena Kulasiri A. , Dingemanse Jasper
Published: September 2007

This study investigated the influence of ethnic origin and, as a secondary objective, sex on the pharmacokinetics of the parenteral endothelin receptor antagonist clazosentan in healthy Caucasian and Japanese subjects. Twelve subjects of each ethnic origin (female/male ratio 1:1) were treated with sequential 4‐hour infusions of 1, 5, and 15 mg/h. Blood samples were taken frequently to determine plasma levels of clazosentan. The exposure to clazosentan was approximately 16% higher in Japanese subjects compared with Caucasian subjects and 18% higher in females compared with males. These differences were mainly attributable to a difference in clearance. A 3‐compartment model well described the plasma concentration–time profiles of clazosentan with disposition half‐lives of approximately 6 minutes, 21 minutes, and 2.7 hours. The data suggest that Caucasian and Japanese patients can be treated with a similar dosing regimen of clazosentan. At the doses infused, administration of clazosentan was safe and well tolerated in both ethnic groups.
Learning Disabilities and Delinquency
Authors: Einat Tomer , Einat Amela
Published: October 2007

Research consistently illustrates that several intellectual disabilities—namely, learning disabilities (LD), low intelligence, challenging behavior, and inadequate adaptive behavior, as well as attention deficit hyperactivity disorder (ADHD)—are considered risk factors for antisocial and criminal behavior. Although much attention has been paid to the relationship of LD, ADHD, and criminal behavior, three research topics have been overlooked: the frequency of LD with ADHD among inmates, the relationship between LD and/or ADHD and level of education among prisoners, and the connection between LD and/or ADHD and age of criminal onset. The present study examined the frequency of LD and ADHD in a sample of Israeli-born prisoners, in addition to the frequency of each category by itself, and it investigated the relationship of LD and/or ADHD, school dropout age, and onset of criminal activity.
Press Coverage of Legislative Appeals by the President
Authors: Barrett Andrew W.
Published: September 2007

By and large, unless the president's public appeals for legislation are reported by the national media, only his immediate audiences will hear them. This article examines 541 presidential legislative appeals from the Reagan and first Bush administrations to determine how often such appeals are reported and which ones generate press coverage. It is discovered that the majority of appeals by the president are not reported. This finding helps explain why presidents struggle to build public support for their proposals, as the public cannot be persuaded by messages it never hears. Presidents themselves appear largely responsible for this limited coverage, as most of their appeals are quite short and not the central focus of their public remarks. However, appeals that meet the press's criteria for newsworthiness are reported more often, particularly those that are most significant to the president and that easily fit the narrative style of reporting favored by journalists.
Thrombotic Thrombocytopenic Purpura and Bone Marrow Necrosis as the Initial Presentation of Lung Cancer
Authors: Sevinc Alper , Kalender Mehmet Emin , Pehlivan Yavuz , Sari Ibrahim , Camci Celalettin
Published: October 2007

Thrombotic thrombocytopenic purpura (TTP) is a disseminated form of thrombotic microangiopathy. Although most cases are held to be idiopathic, its association with malignancy is well recognized, and it usually occurs at the terminal stage of cancer. Bone marrow necrosis (BMN) is another rare disorder defined pathologically as the necrosis of myeloid tissue and medullary stroma with preservation of bone. Although hematologic malignancy is the most common underlying disease associated with BMN, it can also be caused by solid tumors. The occurrence of TTP with BMN associated with lung cancer has not been reported in the English literature. First described is a patient with the rare association of TTP and BMN displayed as the first manifestations of a lung cancer.
Hyperhomocysteinemia Relates to the Subtype of Antiphospholipid Antibodies in Non-SLE Patients
Authors: Wei Hsi Chen  , Hung Sheng Lin  , Yi Fen Kao  , Min Yu Lan  , Jia Shou Liu
Published: October 2007

Abnormal increases of antiphospholipid antibody and plasma homocysteine levels are recently emerging as nonlipidic risk factors for cerebral atherogenesis and thrombosis. Both antiphospholipid antibody and homocysteine share many similar bioeffects in hemostasis, but their interaction is still inconsistent. In this study, we examined the relation between the plasma homocysteine level and lupus anticoagulant, anticardiolipin antibody, and anti-β2-glycoprotein I antibody in patients with noncardiac cerebral ischemia. Systemic lupus erythrematosus patients were excluded. The results showed a higher frequency of moderate hyperhomocysteinemia in patients with an abnormal increase of lupus anticoagulant only. Neither the serum folate and cobalamin levels nor methylenetetrahydrofolate reductase allele mutation contributes to this result. Accordingly, homocysteine interacts with lupus anticoagulant to promote cerebral atherosclerosis and ischemia. The role of vasculopathic or prothrombotic autoantibody generation in response to specific pathological change such as hyperhomocysteinemia warrants further investigation.
Microstructure and electrical properties of Ni–Cr thin films fabricated by ion beam sputtering
Authors: Zhou J. C. , Tian L. , Yan J. W.
Published: September 2007

By ion beam sputtering method, Ni–Cr films were fabricated. Then the films were characterised by X-ray diffraction (XRD), atomic force microscopy (AFM), Alpha-Step IQ profilers, four point probe (FPP) respectively. The thin film electrical properties and its microstructure have been probed into. The gauge factor (GF) of the Ni–Cr thin films was determined by cantilever beam method. The results show that the Ni–Cr thin films can be used as piezoresistive films, which present specific characteristics such as relative small temperature coefficient of resistance (TCR), good GF and high sheet resistance.
Single sided single pass submerged arc welding of austenitic stainless steel
Authors: Chi K. , Maclean M. S. , McPherson N. A. , Baker T. N.
Published: September 2007

The weld metal produced from a series of high productivity welds of 316LN austenitic stainless steel plate was examined to evaluate the effects of the use of a higher heat input process (>2˙5 kJ mm-1). This high heat input process was aimed at maximising single sided weld metal penetration in a single pass using simple square edge preparations and minimising time consuming handling operations. The evaluation was undertaken by correlating the local microstructure with the local toughness and microhardness of the cap, middle and root of the weld. It was established that the intermetallic phases/carbides present did not appear to have a significantly adverse effect on either corrosion or toughness. The phases observed and confirmed by the use of selected area electron diffraction (SAED) were predominantly χ with some σ. No identifications were made of M23C6 observed in other studies of 316LN welds. A series of impact tests with variations in the notch positions showed that the thickness of the δ ferrite had an effect on the weld metal toughness. As a result of the present work it was established that similar volume fractions of δ ferrite did not necessarily produce similar levels of weld metal toughness, but ferrite thickness did appear to have a contributory effect. Welding of 316LN stainless steel with a single sided single pass submerged arc welding process was satisfactorily undertaken up to 20 mm plate thickness without preheat or post-weld heat treatment. The ability to achieve this resulted in significant economic savings within the process for ship panel production combined with satisfactory weld metal properties.
Surface electronic and morphological behaviours of copper under different wearing load conditions
Authors: Zhi W. , Wang H. , Gupta H.
Published: September 2007

In this study, electronic and morphological behaviours, represented by the electron work function and surface roughness respectively, in copper under different wearing conditions such as load and time, were investigated using a scanning Kelvin probe, a tribometer and an atomic force microscope. The results showed that the work function initially decreased with increasing load and time and then became stable after a certain period of time, whereas the surface roughness increased and then became stable. Furthermore, the onset of wear or the history before measurable wear can be reflected based on the response of the work function. The present study demonstrates that the Kelvin probe technique could be promising for the characterisation of wear behaviour particularly at the early stages of wear because of the work function as an extremely sensitive signal.
Quantitative characterisation of last stage solidification in nickel base superalloy using enthalpy based method
Authors: D'Souza N. , Lekstrom M. , Dai H. J. , Shollock B. A. , Dong H. B.
Published: September 2007

An enthalpy based method was used to determine the solidification characteristics in the Ni base superalloy IN713LC with the emphasis on the late stages of solidification. Solidification commences with freezing of γ-solid, which is followed by precipitation of carbides (MC) and subsequent divorced growth of MC and γ until solidification terminates. During solidification enthalpy change was measured using differential thermal analysis and latent heat was calculated using a multicomponent thermodynamic software database. The measured enthalpy and calculated latent heat were then used to determine liquid fraction evolution and local freezing rate. A quantitative comparison of calculated fraction liquid evolution and local freezing rate with those determined using equilibrium and Scheil approximations was carried out. The comparison reveals that the present method offers a more accurate approach for characterising the late stages of solidification than the equilibrium and Scheil models.
Hot strength of creep resistant ferritic steels and relationship to creep rupture data
Authors: Dimitriu R. C. , Bhadeshia H. K. D. H.
Published: September 2007

Experimental data on the tensile strength of ferritic steels designed for prolonged service at elevated temperatures have been assessed as a function of many variables, including the testing temperature. The resulting model has been combined with other data on the intrinsic strength of pure ferritic iron and substitutional solute strengthening to show that there is a regime in the temperature range 780–845 K beyond which there is a rapid decline in the microstructural contribution to strength. This decline cannot be attributed to changes in microstructure, but possibly to the ability of dislocations to overcome obstacles with the help of thermal activation. There is evidence of an approximate relationship between the temperature dependence of hot tensile strength and creep rupture stress.
Modelling steady state deformation of fcc metals by non-equilibrium thermodynamics
Authors: Huang M. , del Castillo P. E. J. Rivera Díaz , van der Zwaag S.
Published: September 2007

The steady state of plastic deformation is modelled by non-equilibrium thermodynamics theory. Based on energy conservation and constant entropy requirements at the steady state, the saturation dislocation density ρ is found to be determined by ρ= λ ϵ/( bvc), where λ is a constant that depends on the material properties, ϵ is the strain rate, b is the magnitude of Burgers vector and vc is the dislocation climb velocity along the dislocation line. Then, by employing the Taylor relation, the saturation flow stress is obtained. The model is applied to four pure fcc single crystals under tensile testing and polycrystalline Al at steady state creep. The predictions are in good agreement with the experimental observations.
Residence and fractionation of rare earth elements during kaolinization of alkaline peraluminous granites in NW Spain
Authors: Galán E. , Fernández-Caliani J. C. , Miras A. , Aparicio P. , Márquez M. G.
Published: October 2007

A geochemical and mineralogical study has allowed us to address the factors controlling distribution pattern, residence and behaviour of rare earth elements (REE) during kaolinization of Variscan granitoids in NW Spain. Mineral composition of the deeply weathered samples is dominated by kaolinite, with minor amounts of quartz, muscovite-illite, alkaline feldspar and traces of resistant minerals (rutile, ilmenite, zircon and monazite). Variable amounts of Si, Na, Ca, K, Rb, Cs, Ba, U and P were lost from the weathering profile, as a result of feldspars, mica and apatite breakdown, whereas Al, Fe, Ti, Zr, Th, Hf and REE were concentrated in the residual kaolin. Chondrite-normalized REE patterns of the kaolins show an overall enrichment of light REE (LaN/SmN = 1.22–2.53), heavy REE depletion (GdN/YbN = 2.42–15.10) and a strong negative Eu anomaly (Eu/Eu* = 0.11–0.25), probably inherited from the parent granite. Nevertheless, the normalization to the parent granite reveals some REE fractionation and increasing positive Eu anomalies with advancing weathering, in response to the breakdown of feldspars. Different grain-size fractions show similar REE distribution patterns, but differ in concentration levels. Although the fine fractions are the most important REE reservoir, there is no positive correlation with clay mineralogy. The correlative behaviour among P2O5, Th and REE in the <2 mm fraction suggests that monazite plays a dominant role controlling the REE budget in the weathering profile.
MicroRNA miR-24 inhibits erythropoiesis by targeting activin type I receptor ALK4
Authors: Wang Qiang , Huang Zheng , Xue Huiling , Jin Chengcheng , Ju Xiu-Li , Han Jing-Dong J. , Chen Ye-Guang
Published: September 2007

MicroRNAs have been suggested to modulate a variety of cellular events. Here we report that miR-24 regulates erythroid differentiation by influencing the expression of human activin type I receptor ALK4 (hALK4). Ectopic expression of miR-24 reduces the mRNA and protein levels of hALK4 by targeting the 3′-untranslated region of hALK4 mRNA and interferes with activin-induced Smad2 phosphorylation and reporter expression. Furthermore, miR-24 represses the activin-mediated accumulation of hemoglobin, an erythroid differentiation marker, in erythroleukemic K562 cells and decreases erythroid colony-forming and burst-forming units of CD34+ hematopoietic progenitor cells. ALK4 expression is inversely correlated with miR-24 expression during the early stages of erythroid differentiation, and the forced expression of miR-24 leads to a delay of activin-induced maturation of hematopoietic progenitor cells in liquid culture. Thus, our findings define a regulation mode of miR-24 on erythropoiesis by impeding ALK4 expression.
Quantitative expression profiling guided by common retroviral insertion sites reveals novel and cell type–specific cancer genes in leukemia
Authors: Sauvageau Martin , Miller Michelle , Lemieux Sébastien , Lessard Julie , Hébert Josée , Sauvageau Guy
Published: September 2007

Proviral insertional mutagenesis is a powerful tool for the discovery of cancer-associated genes. The ability of integrated proviruses to affect gene expression over long distances combined with the lack of methods to determine the expression levels of large numbers of genes in a systematic and truly quantitative manner have limited the identification of cancer genes by proviral insertional mutagenesis. Here, we have characterized a new model of proviral insertional mutagenesis-induced lymphoid tumors derived from Eed Polycomb group gene mutant mice and quantitatively determined the expression levels of all genes within 100 kb of 20 different retroviral common insertion sites (CISs) identified in these tumors. Using high-throughput quantitative reverse transcription–polymerase chain reaction (Q-RT-PCR), we document an average of 13 CIS-associated genes deregulated per tumor, half of which are leukemia subtype–specific, while the others are coordinately deregulated in the majority of tumors analyzed. Interestingly, we find that genes located distantly from common proviral integration sites are as frequently deregulated as proximal genes, with multiple genes affected per integration. Our studies reveal an unsuspected conservation in the group of genes deregulated among phenotypically similar subtypes of lymphoid leukemias, and suggest that identification of common molecular determinants of this disease is within reach.
Validation of ICD-9-CM/ICD-10 coding algorithms for the identification of patients with acetaminophen overdose and hepatotoxicity using administrative data
Authors: Myers Robert P , Leung Yvette , Shaheen Abdel Aziz M , Li Bing
Published: October 2007

Background

Acetaminophen overdose is the most common cause of acute liver failure (ALF). Our objective was to develop coding algorithms using administrative data for identifying patients with acetaminophen overdose and hepatic complications.

Methods

Patients hospitalized for acetaminophen overdose were identified using population-based administrative data (1995–2004). Coding algorithms for acetaminophen overdose, hepatotoxicity (alanine aminotransferase >1,000 U/L) and ALF (encephalopathy and international normalized ratio >1.5) were derived using chart abstraction data as the reference and logistic regression analyses.

Results

Of 1,776 potential acetaminophen overdose cases, the charts of 181 patients were reviewed; 139 (77%) had confirmed acetaminophen overdose. An algorithm including codes 965.4 (ICD-9-CM) and T39.1 (ICD-10) was highly accurate (sensitivity 90% [95% confidence interval 84–94%], specificity 83% [69–93%], positive predictive value 95% [89–98%], negative predictive value 71% [57–83%], c-statistic 0.87 [0.80–0.93]). Algorithms for hepatotoxicity (including codes for hepatic necrosis, toxic hepatitis and encephalopathy) and ALF (hepatic necrosis and encephalopathy) were also highly predictive (c-statistics = 0.88). The accuracy of the algorithms was not affected by age, gender, or ICD coding system, but the acetaminophen overdose algorithm varied between hospitals (c-statistics 0.84–0.98; P = 0.003).

Conclusion

Administrative databases can be used to identify patients with acetaminophen overdose and hepatic complications. If externally validated, these algorithms will facilitate investigations of the epidemiology and outcomes of acetaminophen overdose.
Angiotensin II receptor blockers decreased blood glucose levels: a longitudinal survey using data from electronic medical records
Authors: Kitamura Noboru , Takahashi Yasuo , Yamadate Shuukoh , Asai Satoshi
Published: September 2007

Background

A beneficial effect on glucose metabolism is reported with angiotensin receptor blocker (ARB) treatment of hypertension. The effect on blood glucose level during the course of treatment with ARBs in clinical cases is uncertain. Our objectives were to survey the changes in glucose and HbA1c levels in patients with hypertension over a one-year period, and to study the correlations between these values and the time after the start of ARB therapy.

Methods

We conducted a retrospective longitudinal survey of blood glucose and HbA1c measurements in Japanese patients aged ≥20 years with newly diagnosed hypertension but without diabetes, who had received ARB monotherapy with candesartan cilexetil, losartan potassium, olmesartan medoxomil, telmisartan, or valsartan during the period from December 2004 to November 2005. Data including 2465 measurements of non-fasting blood glucose in 485 patients and 457 measurements of HbA1c in 155 patients were obtained from electronic medical records of Nihon University School of Medicine. Linear mixed effects models were used to analyze the relationship between these longitudinal data of blood examinations and covariates of patient age, sex, medication, and duration of ARB therapy.

Results

Casual blood glucose level was associated with the duration of treatment (P < 0.0001), but not with age, sex, or medication. Blood glucose level was significantly decreased during the periods of 0~3 months (P < 0.0001) and 3~6 months (P = 0.0081) compared with baseline, but was not significantly different between 6~12 months and baseline. There was no association between HbA1c level and covariates of sex, age, medication and duration of treatment.

Conclusion

Our findings provide new clinical evidence that the effects of ARBs on glucose metabolism may change during the course of treatment, suggesting a blood glucose-lowering effect in the short-term after the start of treatment.
A pharmacodynamic analysis of resistance trends in pathogens from patients with infection in intensive care units in the United States between 1993 and 2004
Authors: Eagye Kathryn J , Nicolau David P , Lockhart Shawn R , Quinn John P , Doern Gary V , Gallagher Gale , Abramson Murray A
Published: October 2007

Background

Increasing nosocomial pathogen resistance to available antimicrobial agents is of growing concern. While higher MICs can diminish antimicrobial effectiveness, dose adjustments often mitigate this effect. This study's objective was to ascertain whether MICs among major pathogens in the ICU to several commonly used agents have increased enough to significantly impact their ability to achieve bactericidal effect.

Methods

Cefepime, ceftriaxone, imipenem and piperacillin-tazobactam MICs were determined with 74,394 Gram-negative bacilli obtained from ICU patients with various infections in the US between 1993 and 2004. Results were grouped into four 3-year periods. The predicted cumulative fraction of response (CFR) was estimated based on patient-derived pharmacokinetic values and Monte Carlo simulation. Trends in CFR over the four study periods were assessed using the Cochran-Armitage test. The primary analysis included all organisms combined; Pseudomonas aeruginosa and Acinetobacter species were also evaluated individually.

Results

In the primary analysis, imipenem 500 mg q6h showed CFRs from 87% to 90% across all four study periods, with a trend toward slightly improved bactericidal target attainment (p < 0.01). CFRs for cefepime 2 g q12h and piperacillin-tazobactam 4.5 g q6h both declined by 2% (p < 0.01 and p < 0.05, respectively), reflecting upward shifts in the underlying MIC distributions. Ceftriaxone had <52% CFR for all regimens in all periods, with no significant trend. Against P. aeruginosa, significant declines in CFR were seen for (range, p-value): imipenem 1 g q8h (82%–79%, p < 0.01), cefepime 1 g q12h (70%–67%, p < 0.01), cefepime 2 g q12h (84%–82%, p < 0.05), piperacillin-tazobactam 3.375 g q6h (76%–73%, p < 0.01), piperacillin-tazobactam 4.5 g q8h (71%–68%, p < 0.01), and piperacillin-tazobactam 4.5 g q6h (80%–77%, p < .01). Against Acinetobacter spp., all regimens of imipenem, cefepime and piperacillin-tazobactam showed significant declines in CFR over time (p < 0.01).

Conclusion

Our observations suggest that as a result of increasing antimicrobial resistance among ICU pathogens in the US, drug effectiveness, assessed as a function of individual agents' ability to attain pharmacodynamic targets, has declined, especially with P. aeruginosa and Acinetobacter spp. Cefepime 2 g q8h and imipenem were the most potent agents against these species, respectively. More aggressive dosing of all of the agents characterized could preserve their clinical utility, but this must be balanced with safety and tolerability issues by the physician.
Activities contributing to energy expenditure among Guatemalan adults
Authors: Gregory Cria O , Ramirez-Zea Manuel , Martorell Reynaldo , Stein Aryeh D
Published: October 2007

Background

Guatemala has experienced a substantial increase in overweight and obesity in recent years, yet physical activity patterns and consequent energy expenditure are largely unexplored in this population.

Methods

To describe overall physical activity levels (PAL) and activities contributing to daily energy expenditure, we analyzed time spent in daily activities as reported by 985 women and 819 men, living in rural and urban areas of Guatemala in 2002–04.

Results

Physical activity levels recommended to prevent obesity (PAL ≥ 1.70) differed by residence/occupation among men (agricultural-rural: 77%; nonagricultural-rural: 36%; urban: 24%; P < 0.01), but not women (rural: 2%; urban: 3%; P = 0.5). Median energy expenditure was higher among agricultural-rural men (44 MET*h/d; MET = metabolic equivalent) compared to nonagricultural-rural (37 MET*h/d) and urban men (35 MET*h/d; P < 0.01); energy expenditure was slightly lower among rural compared to urban women (34 MET*h/d vs. 35 MET*h/d; P < 0.01). Occupation was the largest contributor to energy expenditure (19–24 MET*h/d); among women and nonagricultural-rural and urban men this was primarily of a light intensity. Energy expenditure in sedentary activities ranged from 2 MET*h/d among rural women to 6 MET*h/d among agricultural-rural men. Any sports/exercise time was reported by 35% and 5% of men and women, respectively. Nevertheless, the majority of participants believed they were significantly active to stay healthy.

Conclusion

Overall, energy expenditure was low in the population not dedicated to agricultural occupations; an increased focus on active leisure-time behaviors may be needed to counterbalance reductions in energy expenditure consequent to sedentarization of primary occupations.