Analysis of the UBV light curves of TT hydrae by Kopal's frequency domain method

The light curves of the totally eclipsing system TT Hya in UBV colours observed by Kulkarni and Abhyankar during 1973-77 have been analysed by Kopal's frequency domain method with slight modification. We find rs (primary) = 0.104 ± 0.005, rg (secondary) = 0.215 ± 0.008 and i = 89° ± 1°. The value of rg obtained in this study is smaller than that determined earlier by Kulkarni and Abhyankar by the method of Russell and Merrill; this confirms the undersized nature of the secondary component. The ultraviolet colour excess of the secondary is also confirmed

Development of a Nomogram to Evaluate the Usefulness of Sonographic Measurement of Placental Thickness for the Estimation of Fetal Gestational Age

Background: An accurate assessment of gestational age (GA) and evaluation of fetal growth is fundamental to prenatal care. Aim: To evaluate placental thickness (PT) as an indicator of GA. Subjects and Methods: A prospective study was carried out on 300 antenatal patients with known last menstrual period (LMP), 100 each in first, second, and third trimester, respectively, with GA more than 10 weeks till term in a study period of one year. Patients with GA more than 20 weeks detected with pregnancy‑induced hypertension (PIH) and/or diabetes mellitus (DM) and/or intrauterine growth retardation (IUGR) and/or hydrops fetalis and/or congenital malformation were excluded from the study. Twin pregnancy of any gestation was excluded from the study. The PT was measured at the level of insertion of the cord and the values thus measured in millimeters was correlated with GA as ascertained vis a vis the LMP. GA and PT were represented as mean and standard deviation. Correlation between them was evaluated using Pearson’s product moment correlation coefficient. Results: The study showed a positive correlation between GA and PT. PT in millimeter accurately matched the GA in weeks from 14 to 21 weeks of gestation after which it was seen to be lesser than GA by 1-4 mm. Conclusions: PT promises to be an accurate parameter for estimating fetal GA in singleton pregnancies.Keywords: Fetal Gestational age, nomogram, placental thicknes

Very High Energy gamma-ray observations of Mrk 501 using TACTIC imaging gamma-ray telescope during 2005-06

In this paper we report on the Markarian 501 results obtained during our TeV $\gamma$-ray observations from March 11 to May 12, 2005 and February 28 to May 7, 2006 for 112.5 hours with the TACTIC $\gamma$-ray telescope. During 2005 observations for 45.7 hours, the source was found to be in a low state and we have placed an upper limit of 4.62 $\times$ 10$^{-12}$ photons cm$^{-2}$ s$^{-1}$ at 3$\sigma$ level on the integrated TeV $\gamma$-ray flux above 1 TeV from the source direction. However, during the 2006 observations for 66.8h, detailed data analysis revealed the presence of a TeV $\gamma$-ray signal from the source with a statistical significance of 7.5$\sigma$ above $E_{\gamma}\geq$ 1 TeV. The time averaged differential energy spectrum of the source in the energy range 1-11 TeV is found to match well with the power law function of the form ($d\Phi/dE=f_0 E^{-\Gamma}$) with $f_0=(1.66\pm0.52)\times 10^{-11}cm^{-2}s^{-1}TeV^{-1}$ and $\Gamma=2.80\pm0.27$.Comment: 16 pages and 8 Figures Accepted for publication in the Journal of Physics

Probing the Interaction of the Diarylquinoline TMC207 with Its Target Mycobacterial ATP Synthase

Infections with Mycobacterium tuberculosis are substantially increasing on a worldwide scale and new antibiotics are urgently needed to combat concomitantly emerging drug-resistant mycobacterial strains. The diarylquinoline TMC207 is a highly promising drug candidate for treatment of tuberculosis. This compound kills M. tuberculosis by binding to a new target, mycobacterial ATP synthase. In this study we used biochemical assays and binding studies to characterize the interaction between TMC207 and ATP synthase. We show that TMC207 acts independent of the proton motive force and does not compete with protons for a common binding site. The drug is active on mycobacterial ATP synthesis at neutral and acidic pH with no significant change in affinity between pH 5.25 and pH 7.5, indicating that the protonated form of TMC207 is the active drug entity. The interaction of TMC207 with ATP synthase can be explained by a one-site binding mechanism, the drug molecule thus binds to a defined binding site on ATP synthase. TMC207 affinity for its target decreases with increasing ionic strength, suggesting that electrostatic forces play a significant role in drug binding. Our results are consistent with previous docking studies and provide experimental support for a predicted function of TMC207 in mimicking key residues in the proton transfer chain and blocking rotary movement of subunit c during catalysis. Furthermore, the high affinity of TMC207 at low proton motive force and low pH values may in part explain the exceptional ability of this compound to efficiently kill mycobacteria in different microenvironments

Current concepts in diastolic heart failure

Heart failure is a highly prevalent condition, particularly among elderly adults and women. In diastolic heart failureor heart failure with normal ejection fraction-left ventricular systolic function is preserved. Although diastolic heart failure is clinically and radiographically indistinguishable from systolic heart failure, echocardiography can reveal a preserved ejection fraction with abnormal diastolic function. The present article reviews current medical concepts related to diastolic heart failure for medical practitioners, particularly primary care physicians, who play a vital role in the care of patients with heart failure. Treatment options, focusing on calcium channel blockers and angiotensin receptor blockers, are discussed. With early diagnosis and proper management, the prognosis of diastolic heart failure can be more favorable than that of systolic heart failure. J Am Osteopath Assoc. 2008;108:203-209 I ncreasingly, left ventricular (LV) diastolic dysfunction is being recognized as a pathophysiologic entity which predisposes certain patients to a distinct form of heart failure called diastolic heart failure (DHF)-or heart failure with normal ejection fraction (HFNEF). The term diastolic dysfunction indicates abnormal diastolic distensibility, filling, or LV relaxation, regardless of whether the ejection fraction is preserved or abnormal or whether the patient is symptomatic or asymptomatic. Thus, diastolic dysfunction refers to abnormal mechanical (diastolic) properties of the left ventricle and is present in virtually all patients with heart failure. The terms DHF and HFNEF are used to describe patients with the signs and symptoms of heart failure, a preserved ejection fraction, and LV diastolic dysfunction. Epidemiology Epidemiologic studies have suggested that 30% to 50% of patients with active congestive heart failure (CHF) have adequate LV systolic function. 6-10 Kitzman et al 10 found that 8% of patients older than 65 years have heart failure, 55% of whom have a preserved LV ejection fraction (LVEF). In addition, diastolic dysfunction has been shown to affect elderly women more than any other population subgroup. 6,7, Pathophysiology Pressure-Volume Relationships Studies related to pressure and volume changes during ventricular function provide unique insights into the diastolic, systolic, and overall pumping characteristics of the heart. Although a detailed discussion of such pressure and volume changes is beyond the scope of this article, a brief review of common principles is helpful. Patients with DHF have a preserved ejection fraction despite increased LV diastolic pressure and pulmonary venous pressure. These patients have both increased passive stiffness and abnormal active relaxation of the left ventricle, which may work independently to cause abnormal diastolic physiology

Ticagrelor versus clopidogrel in patients with acute coronary syndromes and chronic obstructive pulmonary disease: An analysis from the platelet inhibition and patient outcomes (PLATO) trial

Background Patients with chronic obstructive pulmonary disease (COPD) experiencing acute coronary syndromes (ACS) are at high risk for clinical events. In the Platelet Inhibition and Patient Outcomes (PLATO) trial, ticagrelor versus clopidogrel reduced the primary endpoint of death from vascular causes, myocardial infarction, or stroke after ACS, but increased the incidence of dyspnea, which may lead clinicians to withhold ticagrelor from COPD patients. Methods and Results In 18 624 patients with ACS randomized to treatment with ticagrelor or clopidogrel, history of COPD was recorded in 1085 (5.8%). At 1 year, the primary endpoint occurred in 17.7% of patients with COPD versus 10.4% in those without COPD (P<0.001). The 1‐year event rate for the primary endpoint in COPD patients treated with ticagrelor versus clopidogrel was 14.8% versus 20.6% (hazard ratio [HR]=0.72; 95% confidence interval [CI]: 0.54 to 0.97), for death from any cause 8.4% versus 12.4% (HR=0.70; 95% CI: 0.47 to 1.04), and for PLATO‐defined major bleeding rates at 1 year 14.6% versus 16.6% (HR=0.85; 95% CI: 0.61 to 1.17). Dyspnea occurred more frequently with ticagrelor (26.1% vs. 16.3%; HR=1.71; 95% CI: 1.28 to 2.30). There was no differential increase in the relative risk of dyspnea compared to non‐COPD patients (HR=1.85). No COPD status‐by‐treatment interactions were found, showing consistency with the main trial results. Conclusions In this post‐hoc analysis, COPD patients experienced high rates of ischemic events. Ticagrelor versus clopidogrel reduced and substantially decreased the absolute risk of ischemic events (5.8%) in COPD patients, without increasing overall major bleeding events. The benefit‐risk profile supports the use of ticagrelor in patients with ACS and concomitant COPD. Clinical Trial Registration URL: http://www.clinicaltrials.gov. Unique identifier: NCT00391872