bluuebunny/crossref_metadata_2025 huggingface dataset:
Intravascular ADP and soluble nucleotidases contribute to acute prothrombotic state during vigorous exercise in humans
Authors: Yegutkin Gennady G. , Samburski Sergei S. , Mortensen Stefan P. , Jalkanen Sirpa , González‐Alonso José
Published: January 2007

Extracellular ATP and ADP trigger vasodilatatory and prothrombotic signalling events in the vasculature. Here, we tested the hypothesis that nucleotide turnover is activated in the bloodstream of exercising humans thus contributing to the enhanced platelet reactivity and haemostasis. Right atrial, arterial and venous blood samples were collected from endurance‐trained athletes at rest, during submaximal and maximal cycle ergometer exercise, and after early recovery. ATP‐specific bioluminescent assay, together with high‐performance liquid chromatographic analysis, revealed that plasma ATP and ADP concentrations increased up to 2.5‐fold during maximal exercise. Subsequent flow cytometric analysis showed that plasma from exercising subjects significantly up‐regulated the surface expression of P‐selectin in human platelets and these prothrombotic effects were diminished after scavenging plasma nucleotides with exogenous apyrase. Next, using thin layer chromatographic assays with [γ‐32P]ATP and 3H/14C‐labelled nucleotides, we showed that two soluble nucleotide‐inactivating enzymes, nucleotide pyrophosphatase/phosphodiesterase and nucleoside triphosphate diphosphohydrolase, constitutively circulate in human bloodstream. Strikingly, serum nucleotide pyrophosphatase and hydrolase activities rose during maximal exercise by 20–25 and 80–100%, respectively, and then declined after 30 min recovery. Likewise, soluble nucleotidases were transiently up‐regulated in the venous blood of sedentary subjects during exhaustive exercise. Human serum also contains 5′‐nucleotidase, adenylate kinase and nucleoside diphosphate (NDP) kinase; however, these activities remain unchanged during exercise. In conclusion, intravascular ADP significantly augments platelet activity during strenuous exercise and these prothrombotic responses are counteracted by concurrent release of soluble nucleotide‐inactivating enzymes. These findings provide a novel insight into the mechanisms underlying the enhanced risk of occlusive thrombus formation under exercising conditions.
Counting Low-Copy Number Proteins in a Single Cell
Authors: Huang Bo , Wu Hongkai , Bhaya Devaki , Grossman Arthur , Granier Sebastien , Kobilka Brian K. , Zare Richard N.
Published: January 2007

We have designed a microfluidic device in which we can manipulate, lyse, label, separate, and quantify the protein contents of a single cell using single-molecule fluorescence counting. Generic labeling of proteins is achieved through fluorescent-antibody binding. The use of cylindrical optics enables high-efficiency (≈60%) counting of molecules in micrometer-sized channels. We used this microfluidic device to quantify β
2
adrenergic receptors expressed in insect cells (SF9). We also analyzed phycobiliprotein contents in individual cyanobacterial cells (
Synechococcus
sp. PCC 7942) and observed marked differences in the levels of specific complexes in cell populations that were grown under nitrogen-depleted conditions.
Direct Measurements of the Convective Recycling of the Upper Troposphere
Authors: Bertram Timothy H. , Perring Anne E. , Wooldridge Paul J. , Crounse John D. , Kwan Alan J. , Wennberg Paul O. , Scheuer Eric , Dibb Jack , Avery Melody , Sachse Glen , Vay Stephanie A. , Crawford James H. , McNaughton Cameron S. , Clarke Antony , Pickering Kenneth E. , Fuelberg Henry , Huey Greg , Blake Donald R. , Singh Hanwant B. , Hall Samuel R. , Shetter Richard E. , Fried Alan , Heikes Brian G. , Cohen Ronald C.
Published: January 2007

We present a statistical representation of the aggregate effects of deep convection on the chemistry and dynamics of the upper troposphere (UT) based on direct aircraft observations of the chemical composition of the UT over the eastern United States and Canada during summer. These measurements provide unique observational constraints on the chemistry occurring downwind of convection and the rate at which air in the UT is recycled. These results provide quantitative measures that can be used to evaluate global climate and chemistry models.
Differential Transmission of Actin Motion Within Focal Adhesions
Authors: Hu Ke , Ji Lin , Applegate Kathryn T. , Danuser Gaudenz , Waterman-Storer Clare M.
Published: January 2007

Cell migration requires the transmission of motion generated in the actin cytoskeleton to the extracellular environment through a complex assembly of proteins in focal adhesions. We developed correlational fluorescent speckle microscopy to measure the coupling of focal-adhesion proteins to actin filaments. Different classes of focal-adhesion structural and regulatory molecules exhibited varying degrees of correlated motions with actin filaments, indicating hierarchical transmission of actin motion through focal adhesions. Interactions between vinculin, talin, and actin filaments appear to constitute a slippage interface between the cytoskeleton and integrins, generating a molecular clutch that is regulated during the morphodynamic transitions of cell migration.
Climate Change Affects Marine Fishes Through the Oxygen Limitation of Thermal Tolerance
Authors: Pörtner Hans O. , Knust Rainer
Published: January 2007

A cause-and-effect understanding of climate influences on ecosystems requires evaluation of thermal limits of member species and of their ability to cope with changing temperatures. Laboratory data available for marine fish and invertebrates from various climatic regions led to the hypothesis that, as a unifying principle, a mismatch between the demand for oxygen and the capacity of oxygen supply to tissues is the first mechanism to restrict whole-animal tolerance to thermal extremes. We show in the eelpout,
Zoarces viviparus
, a bioindicator fish species for environmental monitoring from North and Baltic Seas (Helcom), that thermally limited oxygen delivery closely matches environmental temperatures beyond which growth performance and abundance decrease. Decrements in aerobic performance in warming seas will thus be the first process to cause extinction or relocation to cooler waters.
Cosmic Rays: The Highest-Energy Messengers
Authors: Olinto Angela V.
Published: January 2007

The origin of the most energetic particles ever observed, cosmic rays, will begin to be revealed in the next few years. Newly constructed ultrahigh-energy cosmic ray observatories together with high-energy gamma-ray and neutrino observatories are well positioned to unveil this mystery before the centenary of their discovery in 2012. Cosmic ray sources are likely to involve the most energetic phenomena ever witnessed in the universe.
Perspectives on ethics
Authors: Parker C
Published: January 2007

In his recent paper about understanding ethical issues, Boyd suggests that traditional approaches based on principles or people are understood better in terms of perspectives, especially the perspective-based approach of hermeneutics, which he uses for conversation rather than controversy. However, we find that Boyd’s undefined contrast between conversation and controversy does not point to any improvement in communication: disputes occur during conversation and controversy may be conducted in gentle tones. We agree with Boyd, that being prepared to listen and learn are excellent attitudes, but his vague attempts to establish these and similar virtues in hermeneutic theory are not plausible. Additionally, the current controversy about the use of human embryos in stem cell therapy research shows Boyd missing the opportunity to illustrate how conversation would improve understanding.
Acupuncture trials and informed consent
Authors: Miller F G , Kaptchuk T J
Published: January 2007

Participants are often not informed by investigators who conduct randomised, placebo-controlled acupuncture trials that they may receive a sham acupuncture intervention. Instead, they are told that one or more forms of acupuncture are being compared in the study. This deceptive disclosure practice lacks a compelling methodological rationale and violates the ethical requirement to obtain informed consent. Participants in placebo-controlled acupuncture trials should be provided an accurate disclosure regarding the use of sham acupuncture, consistent with the practice of placebo-controlled drug trials.
RESPONSE TO FENG HAO'S PAPER "KISH'S KEY EXCHANGE SCHEME IS INSECURE"
Authors: KISH L. B.
Published: January 2007

In a forthcoming paper in IEE Proceedings Information Security, Feng Hao claims that temperature inaccuracies make the key exchange scheme based on Kirchhoff Loop with Johnson-like Noise insecure. First we point out that this claim is irrelevant for the security of the idealized/mathematical communicator because it violates basic assumptions. Furthermore, in general practical applications, as it has been pointed out in the very first paper, the use of thermal noise is disadvantageous therefore the issue of temperature and its accuracy is unimportant even for the security of common practical realizations. It is important to emphasize that any deviation from the idealized scheme can lead to a finite level of security. Thus, if the above-mentioned author had stressed the inaccuracy of the resistor values; his claim would have been practically valid. However the impact of such systematic errors can be kept under control. Here we cite our relevant analysis (Phys. Lett. A359, (2006) 741-744) of 1% voltage inaccuracy along the line due to wire resistance effects, which can be considered as a general result for inaccuracies of this order. The necessity to build a statistics to extract information during the properly chosen clock time leads to extremely poor eavesdropper statistics and this situation provides a good practical raw bit security that can be orders of magnitude beyond the raw bit security of idealized quantum communicators.
FACTOR RINGS OF PSEUDO-FROBENIUS RINGS
Authors: FAITH CARL
Published: January 2007

If R is right pseudo-Frobenius (= PF), and A is an ideal, when is R/A right PF? Our main result, Theorem 3.7, states that this happens iff the ideal A′ of the basic ring B of R corresponding to A has left annihilator F in B generated by a single element on both sides. Moreover, in this case B/A′ ≈ F in mod-B, (see Theorem 3.5), a property that does not extend to R, that is, in general R/A is not isomorphic to the left annihilator of A. (See Example 4.3(2) and Theorem 4.5.) Theorem 4.6 characterizes Frobenius rings among quasi-Frobenius (QF) rings.

As an application of the main theorem, in Theorem 3.9 we prove that if A is generated as a right or left ideal by an idempotent e, then e is central (and R/A is then trivially right PF along with R). This generalizes the result of F. W. Anderson for quasi-Frobenius rings. (See Theorem 2.2 for a new proof.).

In Proposition 1.6, we prove that a generalization of this result holds for finite products R of full matrix rings over local rings; namely, an ideal A is finitely generated as a right or left ideal iff A is generated by a central idempotent.

We also note a theorem going back to Nakayama, Goursaud, and the author that every factor ring of R is right PF iff R is a uniserial ring. (See Theorem 5.1.).
THE CLOSED-POINT ZARISKI TOPOLOGY FOR IRREDUCIBLE REPRESENTATIONS
Authors: GOODEARL K. R. , LETZTER E. S.
Published: January 2007

In previous work, the second author introduced a topology, for spaces of irreducible representations, that reduces to the classical Zariski topology over commutative rings but provides a proper refinement in various noncommutative settings. In this paper, a concise and elementary description of this refined Zariski topology is presented, under certain hypotheses, for the space of simple left modules over a ring R. Namely, if R is left noetherian (or satisfies the ascending chain condition for semiprimitive ideals), and if R is either a countable dimensional algebra (over a field) or a ring whose (Gabriel-Rentschler) Krull dimension is a countable ordinal, then each closed set of the refined Zariski topology is the union of a finite set with a Zariski closed set. The approach requires certain auxiliary results guaranteeing embeddings of factor rings into direct products of simple modules. Analysis of these embeddings mimics earlier work of the first author and Zimmermann-Huisgen on products of torsion modules.
ON PLOTKIN-OPTIMAL CODES OVER FINITE FROBENIUS RINGS
Authors: GREFERATH MARCUS , McGUIRE GARY , O'SULLIVAN MICHAEL E.
Published: January 2007

We study the Plotkin bound for codes over a finite Frobenius ring R equipped with the homogeneous weight. We show that for codes meeting the Plotkin bound, the distribution on R induced by projection onto a coordinate has an interesting property. We present several constructions of codes meeting the Plotkin bound and of Plotkin-optimal codes. We also investigate the relationship between Butson–Hadamard matrices and codes over R meeting the Plotkin bound.
IL-22-mediated liver cell regeneration is abrogated by SOCS-1/3 overexpression in vitro
Authors: Brand Stephan , Dambacher Julia , Beigel Florian , Zitzmann Kathrin , Heeg Malte H. J. , Weiss Thomas S. , Prüfer Thomas , Olszak Torsten , Steib Christian J. , Storr Martin , Göke Burkhard , Diepolder Helmut , Bilzer Manfred , Thasler Wolfgang E. , Auernhammer Christoph J.
Published: January 2007

The IL-10-like cytokine IL-22 is produced by activated T cells. In this study, we analyzed the role of this cytokine system in hepatic cells. Expression studies were performed by RT-PCR and quantitative PCR. Signal transduction was analyzed by Western blot experiments and ELISA. Cell proliferation was measured by MTS and [3H]thymidine incorporation assays. Hepatocyte regeneration was studied in in vitro restitution assays. Binding of IL-22 to its receptor complex expressed on human hepatic cells and primary human hepatocytes resulted in the activation of MAPKs, Akt, and STAT proteins. IL-22 stimulated cell proliferation and migration, which were both significantly inhibited by the phosphatidylinositol 3-kinase inhibitor wortmannin. IL-22 increased the mRNA expression of suppressor of cytokine signaling (SOCS)-3 and the proinflammatory cytokines IL-6, IL-8, and TNF-α. SOCS-1/3 overexpression abrogated IL-22-induced STAT activation and decreased IL-22-mediated liver cell regeneration. Hepatic IL-22 mRNA expression was detectable in different forms of human hepatitis, and hepatic IL-22 mRNA levels were increased in murine T cell-mediated hepatitis in vivo following cytomegalovirus infection, whereas no significant differences were seen in an in vivo model of ischemia-reperfusion injury. In conclusion, IL-22 promotes liver cell regeneration by increasing hepatic cell proliferation and hepatocyte migration through the activation of Akt and STAT signaling, which is abrogated by SOCS-1/3 overexpression.
Presystemic influences on thirst, salt appetite, and vasopressin secretion in the hypovolemic rat
Authors: Smith Carrie A. , Curtis Kathleen S. , Smith James C. , Stricker Edward M.
Published: January 2007

The present studies investigated the influence of presystemic signals on the control of thirst, salt appetite, and vasopressin (VP) secretion in rats during nonhypotensive hypovolemia. Rats were injected with 30% polyethylene glycol (PEG) solution, deprived of food and water overnight, and then allowed to drink water, 0.15 M NaCl, or 0.30 M NaCl. The PEG treatment, which produced 30–40% plasma volume deficits, elicited rapid intakes in an initial bout of drinking, but rats consumed much more 0.15 M NaCl than water or 0.30 M NaCl. In considering why drinking stopped sooner when water or concentrated saline was ingested, it seemed relevant that little or no change in systemic plasma Na+ concentration was observed during the initial bouts and that the partial repair of hypovolemia was comparable, regardless of which fluid was consumed. In rats that drank 0.15 M NaCl, gastric emptying was fastest and the combined volume of ingested fluid in the stomach and small intestine was largest. These and other observations are consistent with the hypothesis that fluid ingestion by hypovolemic rats is inhibited by distension of the stomach and proximal small intestine and that movement of dilute or concentrated fluid into the small intestine provides another presystemic signal that inhibits thirst or salt appetite, respectively. On the other hand, an early effect of water or saline consumption on VP secretion in PEG-treated rats was not observed, in contrast to recent findings in dehydrated rats. Thus the controls of fluid ingestion and VP secretion are similar but not identical during hypovolemia.
Increased duration of simulated childbirth injuries results in increased time to recovery
Authors: Pan H. Q. , Kerns J. M. , Lin D. L. , Liu S. , Esparza N. , Damaser M. S.
Published: January 2007

Stress urinary incontinence (SUI) development is strongly correlated with vaginal childbirth, particularly increased duration of the second stage of labor. However, the mechanisms of pelvic floor injury leading to SUI are largely unknown. The aim of this study was to determine the effects of increased duration of vaginal distension (VD) on voiding cystometry, leak point pressure testing, and histology. Sixty-nine virgin female rats underwent VD with an inflated balloon for either 1 or 4 h, while 33 age-matched rats were sham-VD controls. Conscious cystometry, leak point pressure testing, and histopathology were determined 4 days, 10 days, and 6 wk after VD. The increase in abdominal pressure to leakage (LPP) during leak point pressure testing was significantly decreased in both distension groups 4 days after distension, indicative of short-term decreased urethral resistance. Ten days after VD, LPP was significantly decreased in the 4-h but not the 1-h distension group, indicating that a longer recovery time is needed after longer distension duration. Six weeks after VD, LPP was not significantly different from sham-VD values, indicating a return toward normal urethral resistance. In contrast, 6 wk after VD of either duration, the distended rats had not undergone the same increase in voided volume as the sham-VD group, suggesting that some effects of VD do not resolve within 6 wk. Both VD groups demonstrated histopathological evidence of acute injuries and tissue remodeling. In conclusion, this experiment suggests pressure-induced hypoxia as a possible mechanism of injury in vaginal delivery.
Vasopressin-induced vasoconstriction: two concentration-dependent signaling pathways
Authors: Henderson Kyle K. , Byron Kenneth L.
Published: January 2007

Current scientific literature generally attributes the vasoconstrictor effects of [Arg8]vasopressin (AVP) to the activation of phospholipase C (PLC) and consequent release of Ca2+ from the sarcoplasmic reticulum. However, half-maximal activation of PLC requires nanomolar concentrations of AVP, whereas vasoconstriction occurs when circulating concentrations of AVP are orders of magnitude lower. Using cultured vascular smooth muscle cells, we previously identified a novel Ca2+ signaling pathway activated by 10–100 pM AVP. This pathway is distinguished from the PLC pathway by its dependence on protein kinase C (PKC) and L-type voltage-sensitive Ca2+ channels (VSCC). In the present study, we used isolated, pressurized rat mesenteric arteries to examine the contributions of these different Ca2+ signaling mechanisms to AVP-induced vasoconstriction. AVP (10−14–10−6 M) induced a concentration-dependent constriction of arteries that was reversible with a V1a vasopressin receptor antagonist. Half-maximal vasoconstriction at 30 pM AVP was prevented by blockade of VSCC with verapamil (10 μM) or by PKC inhibition with calphostin-C (250 nM) or Ro-31-8220 (1 μM). In contrast, acute vasoconstriction induced by 10 nM AVP (maximal) was insensitive to blockade of VSCC or PKC inhibition. However, after 30 min, the remaining vasoconstriction induced by 10 nM AVP was partially dependent on PKC activation and almost fully dependent on VSCC. These results suggest that different Ca2+ signaling mechanisms contribute to AVP-induced vasoconstriction over different ranges of AVP concentration. Vasoconstrictor actions of AVP, at concentrations of AVP found within the systemic circulation, utilize a Ca2+ signaling pathway that is dependent on PKC activation and can be inhibited by Ca2+ channel blockers.
Elevated Levels of β-D-Glucan in Bronchoalveolar Lavage Fluid in Patients with Farmer’s Lung in Miyazaki, Japan
Authors: Ashitani Jun-ichi , Kyoraku Yuka , Yanagi Shigehisa , Matsumoto Nobuhiro , Nakazato Masamitsu
Published: January 2007

Background: Farmers may be often exposed to β-D-glucan in moldy hay, since straw for feed can be stored throughout the year. Objectives: The aim of the present study was to clarify whether levels of β-D-glucan, which modifies immune responses, are high in the respiratory tract in farmer’s lung and whether β-D-glucan participates in the pathogenesis of this condition. Methods: We measured β-D-glucan levels in the bronchoalveolar lavage fluid (BALF) of 10 patients with farmer’s lung, 4 with summer-type hypersensitivity pneumonitis (HP) and 10 healthy volunteers. Interleukin (IL)-8 and tumor necrosis factor (TNF)-α levels in BALF were measured by enzyme-linked immunosorbent assay (ELISA). We investigated the effects of β-D-glucan on nuclear factor (NF)-ĸB activation and on the release of IL-8 and TNF-α from small airway epithelial cells (SAECs) in vitro. Results: β-D-Glucan levels in the BALF of farmer’s lung patients were increased compared to those in patients with summer-type HP and in healthy volunteers. Additionally, IL-8 levels in BALF were higher in farmer’s lung than in summer-type HP, and TNF-α levels were equal in the two patient groups but raised compared to those in healthy volunteers. High, but not low, concentrations of β-D-glucan were found to induce NF-ĸB activation in SAECs. IL-8 levels in the supernatant obtained from SAEC cultures were increased following the addition of β-D-glucan in vitro. Conclusion: BALF from farmer’s lung patients showed high β-D-glucan levels, which may enhance the expression and release of cytokines through NF-ĸB activation in respiratory epithelial cells.
Albumin Activation of NAD(P)H Oxidase Activity Is Mediated via Rac1 in Proximal Tubule Cells
Authors: Whaley-Connell Adam T. , Morris E. Matthew , Rehmer Nathan , Yaghoubian J. Cipporah , Wei Yongzhong , Hayden Melvin R. , Habibi Javad , Stump Craig S. , Sowers James R.
Published: January 2007

Background: Rac1 is a Rho-family small GTP-ase, when activated is pivotal in NAD(P)H oxidase (NOX) activation and generation of reactive oxygen species (ROS). Evidence links Rac1 activation to receptor-mediated albumin endocytosis in the proximal tubule cell (PTC). Thus in states of albumin overload, Rac1 activation could lead to NOX activation and ROS formation in the PTC. Furthermore, accumulating evidence supports that HMG-CoA reductase inhibition may reduce oxidative stress and albuminuria. Methods: To investigate the role of HMG-CoA reductase inhibition of Rac1 and oxidative stress we used the opossum kidney PTC. ROS generation in the PTC was confirmed using oxidative fluorescent dihydroethidium staining. Results: We observed time-dependent increases in NOX activity with bovine serum albumin (albumin) stimulation (500 µg/dl, maximum at 20 min, p < 0.05) that was inhibited in a concentration-dependent manner with the HMG-CoA reductase inhibitor rosuvastatin (1 µM, p < 0.05). Additionally, the Rac1 inhibitor NSC23766 (100 ng/ml) attenuated albumin activation of NOX. Western blot analysis confirmed Rac1 translocation to plasma membrane in the PTC following albumin stimulation and subsequent inhibition by rosuvastatin and NSC23766. Conclusions: These data demonstrate that albumin-mediated increases in NOX activity and ROS in PTC are reversed by inhibition of Rac1 signaling with the use of rosuvastatin.
Increased Risk of Cerebral Hemorrhage in Chinese Male Heavy Drinkers with Mild Liver Disorder
Authors: Peng Giia-Sheun , Yin Shih-Jiun , Cheng Chun-An , Chiu Shao-Wen , Lee Jiunn-Tay , Lin Wei-Wen , Lin Jiann-Chyun , Hsu Yaw-Don
Published: January 2007

Background: Epidemiological evidence suggests that heavy alcohol consumption increases the risk for either stroke or liver disease. The goal of this study was to determine whether heavy drinkers with mild liver disorder (MLD) are at risk of hemorrhagic stroke. Methods:All of the 524 patients recruited were males with a first-ever acute stroke and were consecutively admitted to the Tri-Service General Hospital between January 2000 and December 2001. The risk factors, liver function, stroke subtypes, and hemostatic factors were assessed among 68 patients defined as heavy drinker stroke (HDS) and 456 patients as nonheavy drinker stroke (NHDS). Results: HDS patients had a significantly higher incidence of hemorrhagic stroke than NHDS patients. HDS patients were also associated with significantly higher occurrence of cigarette smoking, hyperuricemia, liver dysfunction, and significantly lower platelet counts. HDS patients with MLD were more likely to have hemorrhagic stroke (76.5%) than HDS patients without MLD (33.3%) and NHDS patients with (40.3%) or without (26.7%) MLD. HDS patients with MLD also exhibited a significantly higher glutamic oxaloacetic transaminase/glutamic pyruvic transaminase ratio (2.0 ± 1.2) and lower platelet number (185,000 ± 85,000 per µl) when compared with HDS patients without MLD (1.4 ± 0.5; 206,000 ± 59,000 per µl) and NHDS patients with (1.1 ± 1.0; 256,000 ± 97,000 per µl) or without (1.4 ± 0.7; 216,000 ± 68,000 per µl) MLD. Conclusions: HDS patients with MLD are at higher risk for hemorrhagic stroke in part due to the changes in hemostatic factors, although other factors may also contribute to hemorrhagic stroke.
Endothelial Function and White Matter Hyperintensities in Older Adults With Cardiovascular Disease
Authors: Hoth Karin F. , Tate David F. , Poppas Athena , Forman Daniel E. , Gunstad John , Moser David J. , Paul Robert H. , Jefferson Angela L. , Haley Andreana P. , Cohen Ronald A.
Published: January 2007

Background and Purpose—

The presence of white matter hyperintensities on brain MRI is common among elderly individuals. Previous research suggests that cardiovascular risk factors are associated with increased white matter hyperintensities. Examining the role of direct physiological measures of vascular function will help to clarify the vascular mechanisms related to white matter hyperintensities. The aim of the present study was to examine the association between endothelial-dependent and endothelial-independent vasodilatation and white matter hyperintensity volume.

Methods—

Twenty-five older adults with a range of cardiovascular diseases underwent brain MRI and completed assessments of blood vessel integrity using endothelial-dependent and independent flow-mediated dilation of the brachial artery. A semi-automated pixel-based method was used to quantify total brain volume and white matter hyperintensity volume, with white matter hyperintensity volume corrected for total brain volume. The association between measures of flow-mediated dilation and log-transformed white matter hyperintensities was examined.

Results—

Correlation analysis revealed that endothelial-dependent vasodilatation was significantly and inversely associated with white matter hyperintensity volume. In contrast, endothelial-independent vasodilatation was not associated with white matter hyperintensities. Neither endothelial-dependent nor endothelial-independent vasodilatation was associated with total brain volume.

Conclusions—

These data provide preliminary evidence that the integrity of the vascular endothelium is associated with white matter hyperintensities in older adults with cardiovascular disease. Impaired vascular function may be one mechanism that contributes to the development of white matter hyperintensities in the brain. Additional longitudinal research combining measures of vessel function, neuroimaging and cognition will be helpful in clarifying this potential mechanism.
Predictors of Outcome in Patients With Cerebral Venous Thrombosis and Intracerebral Hemorrhage
Authors: Girot Marie , Ferro José M. , Canhão Patrícia , Stam Jan , Bousser Marie-Germaine , Barinagarrementeria Fernando , Leys Didier
Published: January 2007

Background and Purpose—

Although intracerebral hemorrhages are frequent in patients with cerebral venous thrombosis, and lead to worse outcome, predictors of outcome in cerebral venous thrombosis patients with intracerebral hemorrhages have never been evaluated in adequately powered studies.

Methods—

This study was conducted as a part of the International Study on Cerebral Vein and Dural Sinus Thrombosis. We evaluated predictors of outcome in cerebral venous thrombosis patients who had an “early intracerebral hemorrhage,” ie, intracerebral hemorrhages already present at time of diagnosis of cerebral venous thrombosis by a logistic regression analysis, with a modified Rankin scale 3 to 6 at month 6 as dependent variable. The same analysis was performed with “delayed intracerebral hemorrhages,” ie, intracerebral hemorrhages that occurred after the diagnosis of cerebral venous thrombosis, as dependent variable.

Results—

Of 624 patients recruited in International Study on Cerebral Vein and Dural Sinus Thrombosis, 245 (39%) had an early intracerebral hemorrhage: at month 6, 51 (21%) of them had a modified Rankin Scale 3 to 6. Independent predictors of having modified Rankin scale 3 to 6 at month 6 were older age (adjusted odds ratio for 1-year increase in age, 1.05; 95% CI, 1.02 to 1.08); male gender (adjusted odds ratio, 3.25; 95% CI, 1.29 to 8.16); having a deep cerebral venous system thrombosis (adjusted odds ratio, 5.43; 95% CI, 1.67 to 17.61) or a right lateral sinus thrombosis (adjusted odds ratio, 2.56; 95% CI, 1.03 to 6.40); and having a motor deficit (adjusted odds ratio, 2.94; 95% CI, 1.21 to 7.10). Of the 36 patients who had a delayed intracerebral hemorrhage, those who had a modified Rankin scale 3 to 6 at month 6 were less likely to have received heparin at the acute stage, and more likely to have had early intracerebral hemorrhage.

Conclusion—

Among patients with early intracerebral hemorrhage, those who were older, men, had a thrombosis of the deep cerebral venous system or of the right lateral sinus, and a motor deficit were at higher risk for death or dependency at month 6. This subgroup of patients with predictors of poor outcome can be the target for new therapeutic strategies.
εPKC May Contribute to the Protective Effect of Hypothermia in a Rat Focal Cerebral Ischemia Model
Authors: Shimohata Takayoshi , Zhao Heng , Steinberg Gary K.
Published: January 2007

Background and Purpose—

Protein kinase C epsilon (εPKC) has been implicated as a neuroprotectant in vitro. We studied εPKC activation (by its localization and proteolysis) in a rodent stroke model and correlated the effects of hypothermia with εPKC activity after cerebral ischemia.

Methods—

Rats were subjected to permanent distal middle cerebral artery occlusion plus 1 hour of bilateral common carotid artery occlusion. Body temperatures were maintained at 37°C or 30°C during common carotid artery occlusion. Brains were harvested at 10 minutes, 4 hours, and 24 hours after common carotid artery release, and the cortex corresponding to the ischemic core and penumbra was dissected. εPKC localization after stroke was assessed by Western blot and immunofluorescence microscopy. A caspase-3 inhibitor was used to test whether εPKC cleavage is caspase dependent.

Results—

εPKC in the membrane fraction and whole-protein homogenates decreased moderately in the penumbra but decreased markedly in the ischemic core. Hypothermia blocked this decrease in both the ischemic core and penumbra. Confocal microscopy confirmed that neuronal εPKC expression decreased in the ischemic core at 4 hours after reperfusion, and this loss was prevented by hypothermia. Two carboxyl-terminal cleavage products of εPKC with molecular masses of 43 and 35 kDa were detected. Although the protein band of 43 kDa decreased after stroke, the 35-kDa band increased. Such changes were not dependent on caspase-3. However, hypothermia blocked changes in the cleavage form of 35 kDa but not 43 kDa after stroke.

Conclusions—

Moderate hypothermia preserves εPKC activity after stroke.
Thermodynamically Equivalent Silicon Models of Voltage-Dependent Ion Channels
Authors: Hynna Kai M. , Boahen Kwabena
Published: January 2007

We model ion channels in silicon by exploiting similarities between the thermodynamic principles that govern ion channels and those that govern transistors. Using just eight transistors, we replicate—for the first time in silicon—the sigmoidal voltage dependence of activation (or inactivation) and the bell-shaped voltage-dependence of its time constant. We derive equations describing the dynamics of our silicon analog and explore its flexibility by varying various parameters. In addition, we validate the design by implementing a channel with a single activation variable. The design's compactness allows tens of thousands of copies to be built on a single chip, facilitating the study of biologically realistic models of neural computation at the network level in silicon.
One-Bit-Matching Theorem for ICA, Convex-Concave Programming on Polyhedral Set, and Distribution Approximation for Combinatorics
Authors: Xu Lei
Published: January 2007

According to the proof by Liu, Chiu, and Xu (2004) on the so-called one-bit-matching conjecture (Xu, Cheung, and Amari, 1998a), all the sources can be separated as long as there is an one-to-one same-sign correspondence between the kurtosis signs of all source probability density functions (pdf's) and the kurtosis signs of all model pdf's, which is widely believed and implicitly supported by many empirical studies. However, this proof is made only in a weak sense that the conjecture is true when the global optimal solution of an independent component analysis criterion is reached. Thus, it cannot support the successes of many existing iterative algorithms that usually converge at one of the local optimal solutions. This article presents a new mathematical proof that is obtained in a strong sense that the conjecture is also true when any one of local optimal solutions is reached in helping to investigating convex-concave programming on a polyhedral set. Theorems are also provided not only on partial separation of sources when there is a partial matching between the kurtosis signs, but also on an interesting duality of maximization and minimization on source separation. Moreover, corollaries are obtained on an interesting duality, with supergaussian sources separated by maximization and subgaussian sources separated by minimization. Also, a corollary is obtained to confirm the symmetric orthogonalization implementation of the kurtosis extreme approach for separating multiple sources in parallel, which works empirically but lacks mathematical proof. Furthermore, a linkage has been set up to combinatorial optimization from a distribution approximation perspective and a Stiefel manifold perspective, with algorithms that guarantee convergence as well as satisfaction of constraints.
Emergency Death Meditations for Internal Alchemists
Authors: Eskildsen Stephen
Published: January 2007

An "emergency death meditation" is a psychic technique performed by a religious adept who has yet to attain the desired level of perfection but faces imminent death. This essay examines a few Daoist examples of such techniques endorsed in late Tang or early Song internal alchemical texts, such as the Taibai huandan pian, Zhen longhu jiuxian jing, and Dongyuanzi neidan jue. These texts describe emergency death meditation methods whereby the practitioner hopes to "enter the womb", "change the dwelling", "repel the killer demons" or "flee the numbers". The intended result is that the Spirit either transfers to another womb or body (in the cases of "entering a womb" and "changing the dwelling") or manages to stay on in its accustomed body (in the cases of "expelling the killer demons" and "fleeing the numbers"). In either case, the adept hopes subsequently to resume training and persevere in it until the Spirit is rendered pure yang and the loftiest mode of immortality is attained. The essay also discusses the intriguing parallels and possible connections between these emergency death meditations (especially "entering the womb") and those taught and practiced in Tantric Buddhist circles. Une "méditation d'urgence au moment de la mort" est une technique psychique utilisée par un adepte n'ayant pas encore atteint le niveau désiré de perfection mais confronté à une mort imminente. Cet article examine quelques exemples taoïstes de telles techniques approuvées par des textes d' alchimie interne datant de la fin des Tang ou du début des Song, tels le Taibai huandan pian, le Zhen long – hu jiuxian jing et le Dongyuanzi neidan jue. Ces texts décrivent des méthodes de méditation d' urgence face à la mort grace auxquelles l'adepte espère "entrer dans l'utérus", "changer de résidence", "repousserles démons tueurs" ou "fuir les nombres". Le résultat attendu est soit que l'Esprit émigre vers un autre utérus ou un autre corps, soit (dans les cas "repousser les démons tueurs" et "fuir les nombres") qu'il réussisse à rester dans son corps habituel. Dans un cas comme dans l'autre l'adepte espère reprendre par la suite sa preparation et persévérer jusqu'à ce que son Esprit devienne pur yang et atteigne le niveau suprême d'immortalité. L'article aborde également les parallèles intéressants et les connexions possibles entre ces techniques de méditation d'urgence (en particulier "entrer dans l'utérus") et celles qui étaient enseignées et pratiquées dans les milieux du bouddhisme tantrique.
Sociocultural Problem-Solving Skills in Preschoolers of High Intellectual Ability
Authors: Nellis Leah M. , Gridley Betty E.
Published: January 2007

This study investigated the ability-related differences in planning skill on a sociocultural task, as well as the performance impact of working with a peer. Shopping routes through a model grocery store were planned by 30 average-ability and 20 high-ability preschool children. All subjects planned a total of five shopping trips. The first and last trips were completed alone, while the three middle trips were either completed alone, with a sane-ability peer, or with a peer of different ability.

Data were analyzed With a series of multivariate analyses of variance (MANOVA) with a within-subjects factor representing the measure of planning skill across Lists 2, 3, and 4. Results indicated that preschool-aged children did not differ in planning skill on the basis of cognitive ability. In addition, high-ability preschoolers performed equally we1l when working alone, with a peer of One ability, or with a peer of less ability.
Gifted Children With Asperger's Syndrome
Authors: Neihart Maureen
Published: January 2007

Asperger's Syndrome is a pervasive developmental disorder characterized by deficits in social comnmniunication and by repetitive patterns of behaviors or interests. It is observed in some ifted children. The author proposes that gifted children with Asperger's Syndromie mnay not be identified because their unusual behaviors may be wrongly attributed to either their giftedness or to a learning disability. The article discusses ways in which Asperger's Syndrome might be missed in gifted children and proposes guidelines for differentiating characteristics of giftedness fromn characteristics of Asperger's Syndrone.
Gifted and Gay: A Study of the Adolescent Experience
Authors: Peterson Jean Sunde
Published: January 2007

A retrospective study of the adolescent experience of 18 gay, lesbian, or bisexual young adults with high ability (12 males, 6 females) using a postpositivistic mode of inquiry found significant themes of danger, isolation, depression, and suicidal ideation, together with high achievement and extreme involvement in activities, in their narrative responses to an extended questionnaire. Participants described personal responses to wondering about sexual orientation, being convinced, and eventually coming out, and the effects on school and family relationships. Half reported awareness by the end of elementary school, and almost all were convinced by grade 11. Most participants offered suggestions for educators in general and for those involved in gifted programs, and many of the suggestions have implications for staff development.
Wisdom as a Form of Giftedness
Authors: Sternberg Robert J.
Published: January 2007

This article describes an important, yet largely neglected, kind of giftedness, namely, wisdom. First, the article discusses how giftedness is identified currently. Second, the article presents an alternative view based on a balance theory of wisdom. The theory is described, and it is shown why the theory offers a useful way of conceptualizinig wisdom. Finally, the article concludes that, given the state of the world, we should have a strong incentive to identify and develop wisdom as a form of giftedness.
Heterogeneity Within the Gifted: Higher IQ Boys Exhibit Behaviors Resembling Boys With Learning Disabilities
Authors: Shaywitz Sally E. , Holahan John M. , Freudenheim Daniele A. , Fletcher Jack M. , Makuch Robert W. , Shaywitz Bennett A.
Published: January 2007

Previous studies of the gifted have been inconsistent, portraying them as both more and less well adjusted than the nongifted or less gifted. We examined behavioral, cognitive, attentional, and family history dimensions among four groups of 87 boys: High Gifted (IQ 140-154), Low Gifted (IQ 124-I 39), Learning Disabled, and a Normal control group. Findings indicated that High Gifted boys exhibit levels of behavior problems similar to the Learning Disabled, whereas Low Gifted boys demonstrate significantly lower levels of behavioral problems than do the Learning Disabled boys. These data provide support for the view of the gifted population as heterogeneous, with the High Gifted exhibiting more behavioral problems than the Low Gifted.
Metacognitive Instrument for Tracking Graduate Student Learning in Gifted Education
Authors: Diket Read M.
Published: January 2007

Variously called concept maps and graphic organizers, cognitive maps can be used in program management as effective and reliable documentation for tracking and evaluating development of students' knowledge, skills, and experience relative to National Association for Gifted Children National Standards for Graduate Programs in Gifted Education. Cognitive structuring of information among teachers is generalized in this report to broader and more advanced levels of professional development fostered in gifted education programs at the graduate level. Longitudinal information from map analysis was used to inform both individual advisement and structural changes in a program.
The Influence of Cooperative Problem Solving on Gender Differences in Achievement, Self-Efficacy, and Attitudes Toward Mathematics in Gifted Students
Authors: Gardunio Edna Leticia Hernandez
Published: January 2007

The purpose of this study was to investigate gender differences in self-efficacy, attitudes toward mathematics, and achievement of 48 gifted seventh- and eighth-grade students after participating in a two-week course on probability and statistics that was taught with a mathematical problemn-solving approach using heuristic strategies. A pretest-posttest control group design was used, in which students were randomly assigned to one of two experimental groups or to a control group during a summnier enrichment program offered to talented students. Although the literature suggests that cooperative learning settings, particularly single-gender groups, are more beneficial for females, no statistical differences in achievement or self-efficacy were found among the groups. Statistically significant differences in attitudes toward mathematics were found favoring students in the whole-group instruction, competitive setting.
Gifts and Talents as Sources of Envy in High School Settings
Authors: Massé Line , Gagné Franfoys
Published: January 2007

This article explores a new empirical approach to explaining some social difficulties experienced by talented students: peer envy toward their gifts and talents. A sample of 689 French Canadian high school students completed two questionnaires addressing both the envy they felt anid the envy expressed toward them. The results focus on two themes: (a) the relative intensity and frequency of envy toward gifts and talents as compared to other potential objects of envy, and (b) the influence of various student characteristics or school settings on the students' answers. The results show a large discrepancy between the envious and envied perspectives. In the first perspective, students did manifest more envy toward their peers' social and financial successes than toward their academic achievements or intelligence. On the other hand, when invited to identify, objects for which they were envied, academic talent became the object most frequently reported.
Multiple Creativities? Investigating Domain-Specificity of Creativity in Young Children
Authors: Han Ki-Soon , Marvin Christine
Published: January 2007

One of the most controversial issues in contemporary research on creativity-whether a person's creativity is domain-specific or domain-general-was investigated with 109 second-grade children. The purposes of this study were to (1) provide empirical support for the domain-specific theory of creativity, (2) show relationships among children's creative performances as measured by three product-based assessments in three domains (storytelling, collage making, and math word problems), and (3) explore the relationship between children's creative performances and their general creative thinking skills, as measured by the Wallach-Kogan Creative Thinking Test and the Real-World Divergent Thinking Test. The findings of this study support the position of domain-specificity of creativity. Children exhibited a range of creative abilities across different domains, rather than a uniform creative abilty in diverse domains, indicating there is considerable intra-individual variation in creative ability by domain. Divergent thinking measures in this study did not predict creative performance in at least two of three, if not all, domains assessed in the study. Implications of the study in connection with educational practices for gifted children are discussed.
Examining Perceptions of Challenge and Choice in Classrooms: The Relationship Between Teachers and Their Students and Comparisons Between Gifted Students and Other Students
Authors: Gentry Marcia , Rizza Mary G. , Owen Steven V
Published: January 2007

In this study we investigated the relationship between what teachers report they do in their classrooms and their students' perceptions of classroom activities with respect to the dimensions of challenge and choice. Students and teachers in elementary school classrooms 91 classrooms) were analyzed separately front those in middle schools classrooms (n = 64 classrooms). No relationship existed between what teachers reported they do and what students perceived is done at the elementary or middle school levels concerning the dimension of challenge. Further, concerning choice, a slight positive correlation existed for elementary students and their teachers, whereas. no such relationship existed at the middle school level. These findings suggest that what teachers report may not be what students actually experience in the classroom. Additionally, differences among perceptions of challenge and choice of gifted students in magnet schools, gifted students in regular schools, and other students in regular schools were investigated. Regardmig challenge, magnet school gifted students reported significantly more challenge than their gifted and other peers at the middle school level, whereas no such differences existed at the elementary level. No meaningful difference existed among the groups on the dimension of choice at either the elementary or middle school levels.