4,053 research outputs found
A simple method of treating seromas involving modified Blalock-Taussig shunts
We treated seromas developing in two patients in relation to left-sided modified Blalock-Taussig shunts by reattaching the original graft to the descending aorta. We postulate that seromas may develop because of the large area of contact between the graft and blood. Shortening the length of the Gore-Tex graft may therefore be a feasible treatment.published_or_final_versio
Heating performance improvement and field study of the induction cooker
Author name used in this publication: K. W. E. ChengAuthor name used in this publication: K. W. ChanRefereed conference paper2008-2009 > Academic research: refereed > Refereed conference paperVersion of RecordPublishe
Lack of structural rearrangement in c-kit and stem cell factor genes in Hong Kong Chinese patients with myelodysplastic syndromes or acute myeloid leukaemia
Stem cell factor is a haemopoietic growth factor that interacts with the c-kit--encoded transmembrane tyrosine kinase receptor during signal transduction in haemopoietic progenitor stem cells. We have screened 127 Chinese patients with myelodysplastic syndromes or acute myeloid leukaemia for structural rearrangements in the stem cell factor and c-kit genes using Southern blot analysis. No structural rearrangements were detected in any of the bone marrow samples that were tested. It seems that structural rearrangements in the stem cell factor and c-kit genes are rare in Hong Kong patients who have a haematological malignancy.published_or_final_versio
Physics at International Linear Collider (ILC)
International Linear Collider (ILC) is an electron-positron collider with the
initial center-of-mass energy of 500 GeV which is upgradable to about 1 TeV
later on. Its goal is to study the physics at TeV scale with unprecedented high
sensitivities. The main topics include precision measurements of the Higgs
particle properties, studies of supersymmtric particles and the underlying
theoretical structure if supersymmetry turns out to be realized in nature,
probing alternative possibilities for the origin of mass, and the cosmological
connections thereof. In many channels, Higgs and leptonic sector in particular,
ILC is substantially more sensitive than LHC, and is complementary to LHC
overall. In this short article, we will have a quick look at the capabilities
of ILC.Comment: To appear in JPSJ Vol76 No1
Analysis of Kelly-optimal portfolios
We investigate the use of Kelly's strategy in the construction of an optimal
portfolio of assets. For lognormally distributed asset returns, we derive
approximate analytical results for the optimal investment fractions in various
settings. We show that when mean returns and volatilities of the assets are
small and there is no risk-free asset, the Kelly-optimal portfolio lies on
Markowitz Efficient Frontier. Since in the investigated case the Kelly approach
forbids short positions and borrowing, often only a small fraction of the
available assets is included in the Kelly-optimal portfolio. This phenomenon,
that we call condensation, is studied analytically in various model scenarios.Comment: 15 pages, 7 figures; extended list of references and some minor
modification
Modulation of human cardiac transient outward potassium current by EGFR tyrosine kinase and Src-family kinases
Aims: The human cardiac transient outward K + current Ito (encoded by Kv4.3 or KCND3) plays an important role in phase 1 rapid repolarization of cardiac action potentials in the heart. However, modulation of I to by intracellular signal transduction is not fully understood. The present study was therefore designed to determine whether/how human atrial I to and hKv4.3 channels stably expressed in HEK 293 cells are regulated by protein tyrosine kinases (PTKs). Methods and results: Whole-cell patch voltage-clamp, immunoprecipitation, western blotting, and site-directed mutagenesis approaches were employed in the present study. We found that human atrial I to was inhibited by the broad-spectrum PTK inhibitor genistein, the selective epidermal growth factor receptor (EGFR) kinase inhibitor AG556, and the Src-family kinases inhibitor PP2. The inhibitory effect was countered by the protein tyrosine phosphatase inhibitor orthovanadate. In HEK 293 cells stably expressing human KCND3, genistein, AG556, and PP2 significantly reduced the hKv4.3 current, and the reduction was antagonized by orthovanadate. Interestingly, orthovanadate also reversed the reduced tyrosine phosphorylation level of hKv4.3 channels by genistein, AG556, or PP2. Mutagenesis revealed that the hKv4.3 mutant Y136F lost the inhibitory response to AG556, while Y108F lost response to PP2. The double-mutant Y108FY136F hKv4.3 channels showed no response to either AG556 or PP2. Conclusion: Our results demonstrate that human atrial Ito and cloned hKv4.3 channels are modulated by EGFR kinase via phosphorylation of the Y136 residue and by Src-family kinases via phosphorylation of the Y108 residue; tyrosine phosphorylation of the channel may be involved in regulating cardiac electrophysiology. Β© The Author 2011.postprin
A contextualização como estruturante curricular na educação em ciΓͺncias : uma discussΓ£o a partir dos documentos oficiaisbra sileiros e artigos especializados
As Diretrizes e Bases da Educação Nacional desencadearam polΓticas educacionais para a redefinição do Ensino MΓ©dio no Brasil. Como parte dessa polΓtica, os ParΓ’metros Curriculares Nacionais incorporam a contextualização como princΓpio curricular central. Empregando anΓ‘lise de conteΓΊdo,analisamos artigos de periΓ³dicos que atribuem diferentes sentidos para a contextualização no Ensino de CiΓͺncias. Com a construção de categorias inspiradas na anΓ‘lise vigotskiana, dimensionamos o conteΓΊdo da contextualização como sentido epistemolΓ³gico/cognitivo, Γ©tico e hΓbridos destes dois.Encontramos a preponderΓ’ncia de um hibridismo entre uma contextualização que busca dar um sentido cognitivo ao conhecimento e uma contextualização que busca um sentido Γ©tico, articulação nem sempre presentes de forma explicita nos documentos oficiais
Scallop swimming kinematics and muscle performance: modelling the effects of "within-animal" variation in temperature sensitivity
Escape behaviour was investigated in Queen scallops (Aequipecten opercularis) acclimated to 5, 10 or 15 degrees C and tested at their acclimation temperature. Scallops are active molluscs, able to escape from predators by jet-propelled swimming using a striated muscle working in opposition to an elastic hinge ligament. The first cycle of the escape response was recorded using high-speed video ( 250 Hz) and whole-animal velocity and acceleration determined. Muscle shortening velocity, force and power output were calculated using measurements of valve movement and jet area, and a simple biomechanical model. The average shortening speed of the adductor muscle had a Q(10) of 2.04, significantly reducing the duration of the jetting phase of the cycle with increased temperature. Muscle lengthening velocity and the overall duration of the clap cycle were changed little over the range 5 - 15 degrees C, as these parameters were controlled by the relatively temperature-insensitive, hinge ligament. Improvements in the average power output of the adductor muscle over the first clap cycle ( 222 vs. 139 W kg(-1) wet mass at 15 and 5 degrees C respectively) were not translated into proportional increases in overall swimming velocity, which was only 32% higher at 15 degrees C ( 0.37m s(-1)) than 5 degrees C (0.28 m s(-1))
Supersymmetry and the LHC Inverse Problem
Given experimental evidence at the LHC for physics beyond the standard model,
how can we determine the nature of the underlying theory? We initiate an
approach to studying the "inverse map" from the space of LHC signatures to the
parameter space of theoretical models within the context of low-energy
supersymmetry, using 1808 LHC observables including essentially all those
suggested in the literature and a 15 dimensional parametrization of the
supersymmetric standard model. We show that the inverse map of a point in
signature space consists of a number of isolated islands in parameter space,
indicating the existence of "degeneracies"--qualitatively different models with
the same LHC signatures. The degeneracies have simple physical
characterizations, largely reflecting discrete ambiguities in electroweak-ino
spectrum, accompanied by small adjustments for the remaining soft parameters.
The number of degeneracies falls in the range 1<d<100, depending on whether or
not sleptons are copiously produced in cascade decays. This number is large
enough to represent a clear challenge but small enough to encourage looking for
new observables that can further break the degeneracies and determine at the
LHC most of the SUSY physics we care about. Degeneracies occur because
signatures are not independent, and our approach allows testing of any new
signature for its independence. Our methods can also be applied to any other
theory of physics beyond the standard model, allowing one to study how model
footprints differ in signature space and to test ways of distinguishing
qualitatively different possibilities for new physics at the LHC.Comment: 55 pages, 30 figure
Self-rated health in middle-aged and elderly Chinese : distribution, determinants and associations with cardio-metabolic risk factors
Background: Self-rated health (SRH) has been demonstrated to be an accurate reflection of a person's health and a valid predictor of incident mortality and chronic morbidity. We aimed to evaluate the distribution and factors associated with SRH and its association with biomarkers of cardio-metabolic diseases among middle-aged and elderly Chinese.
Methods: Survey of 1,458 men and 1,831 women aged 50 to 70 years, conducted in one urban and two rural areas of Beijing and Shanghai in 2005. SRH status was measured and categorized as good (very good and good) vs. not good (fair, poor and very poor). Determinants of SRH and associations with biomarkers of cardio-metabolic diseases were evaluated using logistic regression.
Results: Thirty two percent of participants reported good SRH. Males and rural residents tended to report good SRH. After adjusting for potential confounders, residence, physical activity, employment status, sleep quality and presence of diabetes, cardiovascular disease, and depression were the main determinants of SRH. Those free from cardiovascular disease (OR 3.68; 95%CI 2.39; 5.66), rural residents (OR 1.89; 95% CI 1.47; 2.43), non-depressed participants (OR 2.50; 95% CI 1.67; 3.73) and those with good sleep quality (OR 2.95; 95% CI 2.22; 3.91) had almost twice or over the chance of reporting good SRH compared to their counterparts. There were significant associations -and trend- between SRH and levels of inflammatory markers, insulin levels and insulin resistance.
Conclusion: Only one third of middle-aged and elderly Chinese assessed their health status as good or very good. Although further longitudinal studies are required to confirm our findings, interventions targeting social inequalities, lifestyle patterns might not only contribute to prevent chronic morbidity but as well to improve populations' perceived health
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