1,577 research outputs found
QCD sum rules with finite masses
The concept of QCD sum rules is extended to bound states composed of
particles with finite mass such as scalar quarks or strange quarks. It turns
out that mass corrections become important in this context. The number of
relevant corrections is analyzed in a systematic discussion of the IR- and
UV-divergencies, leading in general to a finite number of corrections. The
results are demonstrated for a system of two massless quarks and two heavy
scalar quarks.Comment: 15 pages, including two pictures to be found in an extra file. Latex
neads epsf.st
Localisation and colocalisation of KK-theory at sets of primes
Given a set of prime numbers S, we localise equivariant bivariant Kasparov
theory at S and compare this localisation with Kasparov theory by an exact
sequence. More precisely, we define the localisation at S to be KK^G(A,B)
tensored with the ring of S-integers Z[S^-1]. We study the properties of the
resulting variants of Kasparov theory.Comment: 16 page
Non-invasive laminar inference with MEG: comparison of methods and source inversion algorithms
Magnetoencephalography (MEG) is a direct measure of neuronal current flow; its anatomical resolution is therefore not constrained by physiology but rather by data quality and the models used to explain these data. Recent simulation work has shown that it is possible to distinguish between signals arising in the deep and superficial cortical laminae given accurate knowledge of these surfaces with respect to the MEG sensors. This previous work has focused around a single inversion scheme (multiple sparse priors) and a single global parametric fit metric (free energy). In this paper we use several different source inversion algorithms and both local and global, as well as parametric and non-parametric fit metrics in order to demonstrate the robustness of the discrimination between layers. We find that only algorithms with some sparsity constraint can successfully be used to make laminar discrimination. Importantly, local t-statistics, global cross-validation and free energy all provide robust and mutually corroborating metrics of fit. We show that discrimination accuracy is affected by patch size estimates, cortical surface features, and lead field strength, which suggests several possible future improvements to this technique. This study demonstrates the possibility of determining the laminar origin of MEG sensor activity, and thus directly testing theories of human cognition that involve laminar- and frequency-specific mechanisms. This possibility can now be achieved using recent developments in high precision MEG, most notably the use of subject-specific head-casts, which allow for significant increases in data quality and therefore anatomically precise MEG recordings
On the speed of convergence to stationarity of the Erlang loss system
We consider the Erlang loss system, characterized by servers, Poisson arrivals and exponential service times, and allow the arrival rate to be a function of We discuss representations and bounds for the rate of convergence to stationarity of the number of customers in the system, and display some bounds for the total variation distance between the time-dependent and stationary distributions. We also pay attention to time-dependent rates
Effect of surface temperature on quantum dynamics of H2 on Cu(111) using a chemically accurate potential energy surface
NWOTheoretical Chemistr
External Fluctuations in a Pattern-Forming Instability
The effect of external fluctuations on the formation of spatial patterns is
analysed by means of a stochastic Swift-Hohenberg model with multiplicative
space-correlated noise. Numerical simulations in two dimensions show a shift of
the bifurcation point controlled by the intensity of the multiplicative noise.
This shift takes place in the ordering direction (i.e. produces patterns), but
its magnitude decreases with that of the noise correlation length. Analytical
arguments are presented to explain these facts.Comment: 11 pages, Revtex, 10 Postscript figures added with psfig style
(included). To appear in Physical Review
Synthesis And Evaluation Of New β-carboline-3-(4-benzylidene)- 4h-oxazol-5-one Derivatives As Antitumor Agents
In the present work, we report the synthesis and in vitro anticancer and antimicrobial activity evaluation of a new series of 1-substituted-β- carboline derivatives bearing a 4-benzylidene-4H-oxazol-5-one unity at C-3. The compound 2-[1-(4- methoxyphenyl)-9H-β-carbolin-3-yl]-4-(benzylidene)-4H- oxazol-5-one (11) was the most active derivative, exhibiting a potent cytotoxic activity against glioma (U251), prostate (PC-3) and ovarian (OVCAR-03) cancer cell lines with IC 50 values of 0.48, 1.50 and 1.07 μM, respectively. An in silico study of the ADME properties of the novel synthesized β-carboline derivatives was also performed. © 2012 by the Authors.17561006113Cao, R., Peng, W., Wang, Z., Xu, A., B-carboline alkaloids: Biochemical and pharmacological functions (2007) Curr. Med. Chem., 14, pp. 479-500Yao, K., Zhao, M., Zhang, X., Wang, Y., Li, L., Zheng, M., Peng, S., A class of oral n-[(1s,3s)-1- methyl-1,2,3,4-tetrahydro-β-carboline- 3-carbonyl]-n-(amino-acid-acyl) hydrazine: Discovery, synthesis, in vitro anti-platelet aggregation/in vivo anti-thrombotic evaluation and 3d qsar analysis (2011) Eur. J. Med. Chem., 46, pp. 3237-3249Bi, W., Bi, Y., Xue, P., Zhang, Y., Gao, X., Wang, Z., Li, M., Gibson, M.K., A new class of β-carboline alkaloid-peptide conjugates with therapeutic efficacy in acute limb ischemia/reperfusion injury (2011) Eur. J. Med. Chem., 46, pp. 1453-1462Liu, J., Jiang, X., Zhao, M., Zhang, X., Zheng, M., Peng, L., Peng, S., A class of 3s-2- aminoacyltetrahydro-b-carboline-3-carboxylic acids: Their facile synthesis, inhibition for platelet activation, and high in vivo anti-thrombotic potency (2010) J. Med. Chem., 53, pp. 3106-3116Costa, E.V., Pinheiro, M.L.B., De Souza, A.D.L., Barison, A., Campos, F.R., Valdez, R.H., Ueda-Nakamura, T., Nakamura, C.V., Trypanocidal activity of oxoaporphine and pyrimidine-b-carboline alkaloids from the branches of annona foetida mart. (annonaceae (2011) Molecules, 16, pp. 9714-9720Polanski, W., Reichmann, H., Gille, G., Stimulation protection and regeneration of dopaminergic neurons by 9-methyl-b-carboline: A new anti-parkinson drug? (2011) Expert Rev. Neurother., 11, pp. 845-860Valdez, R.H., Tonin, L.T.D., Ueda-Nakamura, T., Silva, S.O., Dias, B.P., Kaneshima, E.N., Yamada-Ogatta, S.F., Nakamura, C.V., In vitro and in vivo trypanocidal synergistic activity of n-butyl-1-(4-dimethylamino)phenyl-1,2,3,4-tetrahydro-b- carboline-3-carboxamide) associated with benznidazole (2012) Antimicrob. Agents Chemother., 56, pp. 507-512Ikeda, R., Kurosawa, M., Okabayashi, T., Takei, A., Yoshiwara, M., Kumakura, T., Sakai, N., Ikekita, M., 3-(3-phenoxybenzyl)amino-b-carboline: A novel antitumor drug targeting a-tubulin (2011) Bioorg. Med. Chem. Lett., 21, pp. 4784-4787Shen, L., Park, E.-J., Kondratyuk, P., Guendisch, D., Marler, L., Pezzuto, J.M., Wright, A.D., Sun, D., Design synthesis, and biological evaluation of callophycin a and analogues as potential chemopreventive and anticancer agents (2011) Bioorg. Med. Chem., 19, pp. 6182-6195Chen, Z., Cao, R., Shi, B., Guo, L., Sun, J., Ma, Q., Fan, W., Song, H., Synthesis and biological evaluation of 1,9-disubstituted b-carbolines as potent dna intercalating and cytotoxic agents (2011) Eur. J. Med. Chem., 46, pp. 5127-5137Zhang, X., Yang, Y., Zhao, M., Liu, L., Zheng, M., Wang, Y., Wu, J., Peng, S., A class of trp-trp-aa-obzl: Synthesis, in vitro anti-proliferation/in vivo anti-tumor evaluation, intercalationmechanism investigation and 3d qsar analysis (2011) Eur. J. Med. Chem., 46, pp. 3410-3419Chen, Z., Cao, R., Shi, B., Yi, W., Yu, L., Song, H., Ren, Z., Synthesis and biological evaluation of novel b-carbolines as potent cytotoxic and dna intercalating agents (2010) Chem. Pharm. Bull., 58, pp. 901-907Ma, C., Cao, R., Shi, B., Zhou, X., Ma, Q., Sun, J., Guo, L., Song, H., Synthesis and cytotoxic evaluation of 1-carboxamide and 1-amino side chain substituted b-carbolines (2010) Eur. J. Med. Chem., 45, pp. 5513-5519Chen, Z., Cao, R., Yu, L., Shi, B., Sun, J., Guo, L., Ma, Q., Song, H., Synthesis, cytotoxic activities and dna binding properties of b-carboline derivatives (2010) Eur. J. Med. Chem., 45, pp. 4740-4745Cao, R., Guan, X., Shi, B., Chen, Z., Ren, Z., Peng, W., Song, H., Design synthesis and 3d-qsar of b-carboline derivatives as potent antitumor agents (2010) Eur. J. Med. Chem., 45, pp. 2503-2515Wu, J., Li, C., Zhao, M., Wang, W., Wang, Y., Peng, S., A class of novel carboline intercalators: Their synthesis, in vitro anti-proliferation, in vivo anti-tumor action, and 3d qsar analysis (2010) Bioorg. Med. Chem., 18, pp. 6220-6229Formagio, A.S.N., Tonin, L.T.D., Foglio, M.A., Madjarof, C., De Carvalho, J.E., Da Costa, W.F., Cardoso, F.P., Sarragiotto, M.H., Synthesis and antitumoral activity of novel 3-(2-substituted- 1,3,4-oxadiazol-5-yl) and 3-(5-substituted-1,2,4-triazol-3-yl) b-carboline derivatives (2008) Bioorg. Med. Chem., 16, pp. 9660-9667Savariz, F.C., Formagio, A.S.N., Barbosa, V.A., Foglio, M.A., De Carvalho, J.E., Duarte, M.C.T., Filho, B.P.D., Sarragiotto, M.H., Synthesis, antitumor and antimicrobial activity of novel 1-substituted phenyl-3-[3-alkylamino(methyl)-2-thioxo-1,3,4-oxadiazol-5-yl] b-carboline derivatives (2010) J. Braz. Chem. Soc., 21, pp. 288-298Barbosa, V.A., Formagio, A.S.N., Savariz, F.C., Foglio, M.A., Spindola, H.M., De Carvalho, J.E., Meyer, E., Sarragiotto, M.H., Synthesis and antitumor activity of b-carboline 3- (substitutedcarbohydrazide) derivatives (2011) Bioorg. Med. Chem., 19, pp. 6400-6408Wu, S., Fu, Y., Yan, R., Wu, Y., Lei, X., Ye, S., Synthesis of neamine-carboline conjugates for rna binding and their antibacterial activities (2010) Tetrahedron, 66, pp. 3433-3440Schupp, P., Poehner, T., Edrada, R., Ebel, R., Berg, A., Wray, V., Proksch, P., Eudistomins w and x, two new b-carbolines from the micronesian tunicate eudistoma sp (2003) J. Nat. 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Chem., 49 B, pp. 512-520Perron-Sierra, F.M., Pierré, A., Burbridge, M., Guilbaud, N., Novel bicyclic oxazolone derivatives as anti-angiogenic agents (2002) Bioorg. Med. Chem. Lett., 12, pp. 1463-1466Khan, K.M., Mughal, U.R., Khan, M.T.H., Zia-Ullah, Perveen, S., Choudhary, M.I., Oxazolones new tyrosinase inhibitorssynthesis and their structure-activity relationships (2006) Bioorg. Med. Chem., 14, pp. 6027-6033Mesaik, M.A., Rahat, S., Khan, K.M., Zia-Ullah Choudhary, M.I., Murad, S., Ismail, Z., Atta-Ur-Rahman Ahmad, A., Synthesis and immunomodulatory properties of selected oxazolone derivatives (2004) Bioorg. Med. Chem., 12, pp. 2049-2057Bala, S., Saini, M., Kamboj, S., Methods for synthesis of oxazolones: A review (2011) Int. J. 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Electron Rearrangement Dynamics in Dissociating I 2 n Molecules Accessed by Extreme Ultraviolet Pump Probe Experiments
The charge rearrangement in dissociating In 2 molecules is measured as a function of the internuclear distance R using extreme ultraviolet pulses delivered by the free electron laser in Hamburg. Within an extreme ultraviolet pump probe scheme, the first pulse initiates dissociation by multiply ionizing I2, and the delayed probe pulse further ionizes one of the two fragments at a given time, thus triggering charge rearrangement at a well defined R. The electron transfer between the fragments is monitored by analyzing the delay dependent ion kinetic energies and charge states. The experimental results are in very good agreement with predictions of the classical over the barrier model demonstrating its validity in a thus far unexplored quasimolecular regime relevant for free electron laser, plasma, and chemistry application
Accuracy of the electronic health record’s problem list in describing multimorbidity in patients with heart failure in the emergency department
Patients with heart failure (HF) often suffer from multimorbidity. Rapid assessment of multimorbidity is important for minimizing the risk of harmful drug-disease and drug-drug interactions. We assessed the accuracy of using the electronic health record (EHR) problem list to identify comorbid conditions among patients with chronic HF in the emergency department (ED). A retrospective chart review study was performed on a random sample of 200 patients age ≥65 years with a diagnosis of HF presenting to an academic ED in 2019. We assessed participant chronic conditions using: (1) structured chart review (gold standard) and (2) an EHR-based algorithm using the problem list. Chronic conditions were classified into 37 disease domains using the Agency for Healthcare Research Quality’s Elixhauser Comorbidity Software. For each disease domain, we report the sensitivity, specificity, positive predictive value, and negative predictive of using an EHR-based algorithm. We calculated the intra-class correlation coefficient (ICC) to assess overall agreement on Elixhauser domain count between chart review and problem list. Patients with HF had a mean of 5.4 chronic conditions (SD 2.1) in the chart review and a mean of 4.1 chronic conditions (SD 2.1) in the EHR-based problem list. The five most prevalent domains were uncomplicated hypertension (90%), obesity (42%), chronic pulmonary disease (38%), deficiency anemias (33%), and diabetes with chronic complications (30.5%). The positive predictive value and negative predictive value of using the EHR-based problem list was greater than 90% for 24/37 and 32/37 disease domains, respectively. The EHR-based problem list correctly identified 3.7 domains per patient and misclassified 2.0 domains per patient. Overall, the ICC in comparing Elixhauser domain count was 0.77 (95% CI: 0.71-0.82). The EHR-based problem list captures multimorbidity with moderate-to-good accuracy in patient with HF in the ED
Multi-site reproducibility of prefrontal-hippocampal connectivity estimates by stochastic DCM.
This study examined the reproducibility of prefrontal-hippocampal connectivity estimates obtained by stochastic dynamic causal modeling (sDCM). 180 healthy subjects were measured by functional magnetic resonance imaging (fMRI) during a standard working memory N-Back task at three different sites (Mannheim, Bonn, Berlin; each with 60 participants). The reproducibility of regional activations in key regions for working memory (dorsolateral prefrontal cortex, DLPFC; hippocampal formation, HF) was evaluated using conjunction analyses across locations. These analyses showed consistent activation of right DLPFC and deactivation of left HF across all three different sites. The effective connectivity between DLPFC and HF was analyzed using a simple two-region sDCM. For each subject, we evaluated sixty-seven alternative sDCMs and compared their relative plausibility using Bayesian model selection (BMS). Across all locations, BMS consistently revealed the same winning model, with the 2-Back working memory condition as driving input to both DLPFC and HF and with a connection from DLPFC to HF. Statistical tests on the sDCM parameter estimates did not show any significant differences across the three sites. The consistency of both the BMS results and model parameter estimates indicates the reliability of sDCM in our paradigm. This provides a basis for future genetic and clinical studies using this approach
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